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Howlett, Isela D., Wanglei Han, Michael Gordon, Photini Rice, Jennifer K. Barton, and Raymond K. Kostuk. "Volume holographic imaging endoscopic design and construction techniques." SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2017. http://hdl.handle.net/10150/624713.
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A reflectance volume holographic imaging (VHI) endoscope has been designed for simultaneous in vivo imaging of surface and subsurface tissue structures. Prior utilization of VHI systems has been limited to ex vivo tissue imaging. The VHI system presented in this work is designed for laparoscopic use. It consists of a probe section that relays light from the tissue sample to a handheld unit that contains the VHI microscope. The probe section is constructed from gradient index (GRIN) lenses that form a 1: 1 relay for image collection. The probe has an outer diameter of 3.8 mm and is capable of achieving 228.1 lp/mm resolution with 660-nm Kohler illumination. The handheld optical section operates with a magnification of 13.9 and a field of view of 390 mu m x 244 mu m. System performance is assessed through imaging of 1951 USAF resolution targets and soft tissue samples. The system has also passed sterilization procedures required for surgical use and has been used in two laparoscopic surgical procedures. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
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Wolf, Michael Trevor. "Digital holographic imaging of microorganisms." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36684.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 25).
Imaging aquatic microorganisms in 3D space is of interest to biologists and ocean scientists seeking to understand the behavior of these organisms in their natural environments. In this research, digital holographic imaging (DHI), with a 4f system providing transverse magnification of 9.1, is used to study such microorganisms. To test the imaging technique, DHI was used to locate and track 10 micrometer Dunaliella freely swimming in a 30 milliliter tank of artificial ocean water. Multiple holograms were recorded onto one frame with laser pulsing to identify short algae trajectories. An automatic algae locating program was designed, but the signal to noise ratio was too low, and therefore the program could only locate algae reliably with manual confirmation. With refinement to the experimental setup, the signal to noise ratio could be increased, and this imaging technique could be used to analyze many systems of aquatic microorganisms interacting in a 3D space.
by Michael Trevor Wolf.
S.B.
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Sun, Wenyang. "Profilometry with volume holographic imaging." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35631.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 127-133).
High resolution, non-contact object profile measurement (profilometry) at long working distance is important in a number of application areas, such as precise parts manufacturing, optical element grounding and polishing, adversary target identification in military, terrace profiling, etc. The Volume Holographic (VH) lens is a novel optical element which process the incident light field in a 3D fashion. It has been shown with promising applications in object profile acquisition and 3D imaging areas. In this thesis, we propose, design and implemented a number of volume holographic computational imaging systems for profilometry related applications. We show that the rich functionalities of the VH lens can be exploited to process the incident optical field. Some of the unique imaging behavior can not be easily achieved by using conventional optics. We first develop the theoretical framework for investigating the VH lens optical behavior. We concentrate on a simple design: using the VH lens as the spatial spectrum plane filter in a 4F imaging system. We derived the point spread function (PSF), the depth resolution, the diffraction field distribution of the proposed imaging system. Experimental system characterization and profilometry measurements were carried out with our setups.
(cont.) We find the resolution of the volume holographic imaging (VHI) profilometry system degrades quadratically with the increase of working distance. We addressed this problem by two approaches: 1. We discuss the effect of objective optics design on the VHI resolution. We proposed and implemented the use of appropriately designed telephoto objective optics to achieve very good resolution at long working distance. 2. We developed a maximum likelihood estimation based post-processing method to improve the depth resolution by more than 5 times. An important issue on VHI profilometry is the "slit-shaped" limited field of view (FoV). This makes measurement over the entire big object is very time consuming because scanning is necessary. Otherwise hundreds or thousands of VH lenses must be multiplexed on a single crystal to concatenate the slit FoV of each VH lens to form a wide exit window. However the multiplexing method suffers the "M/#" penalty on photon efficiency. We solved this problem by utilizing the wavelength degeneracy of the VH lens and designed a rainbow illumination VHI to expand the FoV.
(cont.) We also extended the application of VHI to hyper-spectral imaging. The experimental implementation of the hyper-spectral imaging system shows it is capable of not only reconstructing the 3D spatial profile but also restoring the spectral information of the object, both at high resolution. Finally, we conclude with some directions for the future work in this emerging field.
by Wenyang Sun.
Ph.D.
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Domínguez-Caballero, José Antonio. "Digital holographic imaging of aquatic species." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35655.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 160-174).
The aim of this thesis is to design, develop and implement a digital holographic imaging (DHI) system, capable of capturing three-dimensional (3D) images of aquatic species. The images produced by this system are used in a non-intrusive manner to characterize the abundance, morphology and 3D location of the aquatic species. The DHI system operates by recording the hologram produced by the interference between a reference wave and the wave scatter by a coherently illuminated object with a charge-couple-device (CCD). The recorded hologram contains information about the amplitude and phase of the optical field as modified by the object. This optical field is retrieved by numerical algorithms, which enable the reconstruction of the field at different distances relative to the detector from a single hologram. The recording of the holograms with the CCD allows the implementation of image post-processing techniques intended to enhance the reconstructed images. A description of the optimization of the reconstruction by means of an auto-scan algorithm and the reconstruction of large holograms are discussed. It is found that the in-line single-beam experimental set-up is the most suitable configuration for underwater imaging of aquatic species.
(cont.) This is experimentally verified by imaging brine shrimp and copepods under various conditions. Small, sub-10um features of the objects were successfully resolved. It is also found that by using configurations with a spherical reference wave, resolutions comparable to those obtained by a conventional optical microscope can be achieved in a "lens-free" approach with larger working distances.
by José Antonio Domínguez-Caballero.
S.M.
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Howlett, Isela Danielle, and Isela Danielle Howlett. "Endoscope Design for Volume Holographic Imaging." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625584.
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Early stage detection of cancerous tissue is critical to increasing the 5-year survival rate for patients. The development of devices capable of accessing and visualizing these tissue sites plays an important role in this process. Many cancer types have existing screening methods however many have proven ineffective in large clinical trials. Since early stages of cancer development often has subtle changes from normal tissue, traditional non-invasive imaging techniques such as ultrasound or magnetic resonance imaging are not able to detect them. The following work evaluates the feasibility of miniaturization of Volume Holographic Imaging (VHI) systems into laparoscopic endoscopes for tissue and cancer screening.
The work is divided into two main sections discussing the design and evaluation of each imaging system. The first system is a Reflectance VHI Endoscope designed for simultaneous imaging of two imaging depths within a tissue sample. The system is evaluated for resolution and contrast through imaging of resolution bar targets and soft tissue samples. The second system is a Wavelength Coded VHI Endoscope which combines the Reflectance VHI Endoscope imaging properties with axial chromatic dispersion effects of Gradient Index (GRIN) optics to improve the volume holographic element performance and reduce excess background light. Both Reflectance and Wavelength Coded VHI systems utilize a sub-4 mm diameter rigid relay probe which has been approved for in-vivo applications.
The sub-4.4 µm/lp resolution produced by both VHI Endoscope systems and tissue depth separations of 50 µm and 100 µm for the Reflectance and Wavelength Coded designs, respectively, make VHI systems a candidate for clinical evaluation of early stage cancer development.
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Liu, Changgeng. "Coherent Digital Holographic Adaptive Optics." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5527.
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A new type of adaptive optics (AO) based on the principles of digital holography (DH) is proposed and developed for the use in wide-field and confocal retinal imaging. Digital holographic adaptive optics (DHAO) dispenses with the wavefront sensor and wavefront corrector of the conventional AO system. DH is an emergent imaging technology that gives direct numerical access to the phase of the optical field, thus allowing precise control and manipulation of the optical field. Incorporation of DH in an ophthalmic imaging system can lead to versatile imaging capabilities at substantially reduced complexity and cost of the instrument. A typical conventional AO system includes several critical hardware pieces: spatial light modulator, lenslet array, and a second CCD camera in addition to the camera for imaging. The proposed DHAO system replaces these hardware components with numerical processing for wavefront measurement and compensation of aberration through the principles of DH.
We first design an image plane DHAO system which is basically simulating the process the conventional AO system and replacing the hardware pieces and complicated control procedures by DH and related numerical processing. In this original DHAO system, CCD is put at the image plane of the pupil plane of the eye lens. The image of the aberration is obtained by a digital hologram or guide star hologram. The full optical field is captured by a second digital hologram. Because CCD is not at the conjugate plane of the sample, a numerical propagation is necessary to find the image of the sample after the numerical aberration compensation at the CCD plane. The theory, simulations and experiments using an eye model have clearly demonstrated the effectiveness of the DHAO. This original DHAO system is described in Chapter 2.
Different from the conventional AO system, DHAO is a coherent imaging modality which gives more access to the optical field and allows more freedom in the optical system design. In fact, CCD does not have to be put at the image plane of the CCD. This idea was first explored by testing a Fourier transform DHAO system (FTDHAO). In the FTDHAO, the CCD can directly record the amplitude point spread function (PSF) of the system, making it easier to determine the correct guide star hologram. CCD is also at the image plane of the target. The signal becomes stronger than the image plane DHAO system, especially for the phase aberration sensing. Also, the numerical propagation is not necessary. In the FTDHAO imaging system, the phase aberration at the eye pupil can be retrieved by an inverse Fourier transform (FT) of the guide star hologram and the complex amplitude of the full field optical field at the eye pupil can be obtained by an inverse FT of the full field hologram. The correction takes place at the eye pupil, instead of the CCD plane. Taking FT of the corrected field at the eye pupil, the corrected image can be obtained. The theory, simulations, and experiments on FTDHAO are detailed in chapter 3.
The successful demonstration of FTDHAO encourages us to test the feasibility of putting CCD at an arbitrary diffraction plane in the DHAO system. Through theoretical formulation by use of paraxial optical theory, we developed a correction method by correlation for the general optical system to perform the DHAO. In this method, a global quadratic phase term has to be removed before the correction operation. In the formulation, it is quite surprising to find that the defocus term can be eliminated in the correlation operation. The detailed formulations, related simulations, and experimental demonstrations are presented in Chapter 4.
To apply the DHAO to the confocal retinal imaging system, we first transformed the conventional line-scanning confocal imaging system into a digital form. That means each line scan is turned into a digital hologram. The complex amplitude of the optical field from each slice of the sample and aberration of the optical system can be retrieved by digital holographic process. In Chapter 5, we report our experiments on this digital line-scanning confocal imaging system. This digital line-scanning confocal image absorbs the merits of the conventional line-scanning confocal imaging system and DH. High-contrast intensity images with low coherent noise, and the optical sectioning capability are made available due to the confocality. Phase profiles of the samples become accessible thanks to DH. The quantitative phase map is even better than that from the wide field DH.
We then explore the possibility of applying DHAO to this newly developed digital line-scanning confocal imaging system. Since optical field of each line scan can be achieved by the DH, the aberration contained in this field can be eliminated if we are able to obtain the phase aberration. We have demonstrated that the phase aberration can be obtained by a guide star hologram in the wide field DHAO systems. We then apply this technique to acquire the aberration at the eye pupil, remove this aberration from the optical fields of the line scans and recover the confocal image. To circumvent the effect of phase aberration on the line illumination, a small collimated laser beam is shone on the cylindrical lens. Thus the image is solely blurred by the second passage through the aberrator. This way, we can clearly demonstrate the effect of DHAO on the digital line-scanning confocal image system. Simulations and experiments are presented in chapter 6, which clearly demonstrates the validity of this idea. Since line-scanning confocal imaging system using spatially coherent light sources has proven an effective imaging tool for retinal imaging, the presented digital adaptive optics line-scanning confocal imaging system is quite promising to become a compact digital adaptive optics laser scanning confocal ophthalmoscope.
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Lin, Haibo Yu Ping. "Speckle mechanism in holographic optical coherence imaging." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6184.
Full textAbstract:
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 15, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Ping Yu. Vita. Includes bibliographical references.
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de, Leon Erich Ernesto. "Optical Design of Volume Holographic Imaging Systems for Microscopy." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/242357.
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Confocal microscopy rejects out of focus light from the object by scanning a pinhole through the object and constructing the image point by point. Volume holographic imaging (VHI) systems with bright-field illumination have been proposed as an alternative to conventional confocal type microscopes. VHI systems are an imaging modality that does not require scanning of a pinhole or a slit and thus provides video rate imaging of 3-dimensional objects. However, due to the wavelength-position degeneracy of the hologram, these systems produce less than optimal optical sectioning because the high selectivity of the volume hologram is not utilized. In this dissertation a generalized method for the design of VHI systems applied to microscopy is developed. Discussion includes the inter-relationships between the dispersive, degenerate, and depth axes of the system. Novel designs to remove the wavelength-position degeneracy and improve optical sectioning in these systems are also considered. Optimization of a fluorescence imaging system and of dual-grating confocal-rainbow designs are investigated. A ray-trace simulation that integrates the hologram diffraction efficiency and imaging results is constructed and an experimental system evaluated to demonstrate the optimization method. This results in an empirical relation between depth resolution and design tolerances. The dispersion and construction tolerances of a confocal-rainbow volume holographic imaging system are defined by the Bragg selectivity of the holograms. It is found that a broad diffraction efficiency profile of the illumination hologram with a narrow imaging hologram profile is an optimal balance between field of view, construction alignment, and depth resolution. The approach in this research is directly applicable towards imaging ovarian cells for the detection of cancer. Modeling methods, illumination design, eliminating the wavelength degeneracy of the hologram, and incorporating florescence imaging capability are emphasized in this dissertation. Results from this research may be used not only for biomedical imaging, but also for the design of volume holographic systems for both imaging and sensor applications in other fields including manufacturing (e.g. pharmaceutical), aerospace (e.g. LIDAR), and the physical sciences (e.g. climate change).
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Domínguez-Caballero, José Antonio. "Optimization of the holographic process for imaging and lithography." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57696.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 272-297).
Since their invention in 1948 by Dennis Gabor, holograms have demonstrated to be important components of a variety of optical systems and their implementation in new fields and methods is expected to continue growing. Their ability to encode 3D optical fields on a 2D plane opened the possibility of novel applications for imaging and lithography. In the traditional form, holograms are produced by the interference of a reference and object waves recording the phase and amplitude of the complex field. The holographic process has been extended to include different recording materials and methods. The increasing demand for holographic-based systems is followed by a need for efficient optimization tools designed for maximizing the performance of the optical system. In this thesis, a variety of multi-domain optimization tools designed to improve the performance of holographic optical systems are proposed. These tools are designed to be robust, computationally efficient and sufficiently general to be applied when designing various holographic systems. All the major forms of holographic elements are studied: computer generated holograms, thin and thick conventional holograms, numerically simulated holograms and digital holograms. Novel holographic optical systems for imaging and lithography are proposed. In the case of lithography, a high-resolution system based on Fresnel domain computer generated holograms (CGHs) is presented. The holograms are numerically designed using a reduced complexity hybrid optimization algorithm (HOA) based on genetic algorithms (GAs) and the modified error reduction (MER) method. The algorithm is efficiently implemented on a graphic processing unit. Simulations as well as experimental results for CGHs fabricated using electron-beam lithography are presented. A method for extending the system's depth of focus is proposed. The HOA is extended for the design and optimization of multispectral CGHs applied for high efficiency solar concentration and spectral splitting. A second lithographic system based on optically recorded total internal reflection (TIR) holograms is studied. A comparative analysis between scalar and (cont.) vector diffraction theories for the modeling and simulation of the system is performed.
A complete numerical model of the system is conducted including the photoresist response and first order models for shrinkage of the holographic emulsion. A novel block-stitching algorithm is introduced for the calculation of large diffraction patterns that allows overcoming current computational limitations of memory and processing time. The numerical model is implemented for optimizing the system's performance as well as redesigning the mask to account for potential fabrication errors. The simulation results are compared to experimentally measured data. In the case of imaging, a segmented aperture thin imager based on holographically corrected gradient index lenses (GRIN) is proposed. The compound system is constrained to a maximum thickness of 5mm and utilizes an optically recorded hologram for correcting high-order optical aberrations of the GRIN lens array. The imager is analyzed using system and information theories. A multi-domain optimization approach is implemented based on GAs for maximizing the system's channel capacity and hence improving the information extraction or encoding process. A decoding or reconstruction strategy is implemented using the superresolution algorithm. Experimental results for the optimization of the hologram's recording process and the tomographic measurement of the system's space-variant point spread function are presented. A second imaging system for the measurement of complex fluid flows by tracking micron sized particles using digital holography is studied. A stochastic theoretical model based on a stability metric similar to the channel capacity for a Gaussian channel is presented and used to optimize the system. The theoretical model is first derived for the extreme case of point source particles using Rayleigh scattering and scalar diffraction theory formulations. The model is then extended to account for particles of variable sizes using Mie theory for the scattering of homogeneous dielectric spherical particles. The influence and statistics of the particle density dependent cross-talk noise are studied. Simulation and experimental results for finding the optimum particle density based on the stability metric are presented. For all the studied systems, a sensitivity analysis is performed to predict and assist in the correction of potential fabrication or calibration errors.
by José Antonio Domínguez-Caballero.
Ph.D.
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Hubel, Paul Matthew. "Colour reflection holography." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257949.
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El, Mallahi Ahmed. "Automated 3D object analysis by digital holographic microscopy." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209489.
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The main objective of this thesis is the development of new processing techniques for digital holograms. The present work is part of the HoloFlow project that intends to integrate the DHM technology for the monitoring of water quality. Different tools for an automated analysis of digital holograms have been developed to detect, refocus and classify particles in continuous fluid flows. A detailed study of the refocusing criterion permits to determine its dependencies and to quantify its robustness. An automated detection procedure has been developed to determine automatically the 3D positions of organisms flowing in the experiment volume. Two detection techniques are proposed: a usual method based on a global threshold and a new robust and generic method based on propagation matrices, allowing to considerably increase the amount of detected organisms (up to 95 %) and the reliability of the detection. To handle the case of aggregates of particles commonly encountered when working with large concentrations, a new separation procedure, based on a complete analysis of the evolution of the focus planes, has been proposed. This method allows the separation aggregates up to an overlapping area of around 80 %. These processing tools have been used to classify organisms where the use of the full interferometric information of species enables high classifier performances to be reached (higher than 93 %).Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Shih, Tina 1982. "Three dimensional imaging of translucent objects using volume holographic techniques." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32786.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 25-26).
Plankton is a primitive form of one or several-celled organism that lives in the sea. Its behavior, its formation, and the various life patterns, when monitored, reveals a wealth of information about the sea. Three dimensional in-situ images of these semi-translucent organisms are therefore of great interest. To better understand how volume holographic imaging works on a translucent object like plankton, this project explores the three dimensional imaging of a gummy bear. Tomographic experiments were performed both with monochromatic laser light illumination and broadband white-light illumination. It was found that unexpectedly, the white light illumination, though not a perfect tomographic setup because of the inclusion of a lot of scattered and refracted light, images better in three dimensions than the monochromatic laser illumination.
by Tina Shih.
S.B.
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Feng, Z. "A signal processing method for the acoustic image reconstruction of planar objects." Thesis, University of Portsmouth, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234728.
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Blasiak, Thomas C. "Modeling holographic grating imaging systems using the angular spectrum propagation method /." Link to online version, 2006. https://ritdml.rit.edu/dspace/handle/1850/2294.
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Chen, Jhen-Si. "Holographic 3D image display : layer-based method and coarse integrated holograms." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708806.
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Watson, Jonathan M. "Evaluation of spatial-spectral filtering in non-paraxial volume holographic imaging systems." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44854.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 144-148).
In this thesis, the properties of transmission-mode volume phase holograms as spatial-spectral filters in optical systems for microscopic medical imaging are evaluated. In experiment, the relationship between the angle of incidence and diffraction efficiency are invesitgated for wavelength-detuned multiplex holograms to establish the limits of the narrow bandwidth lateral field of view. The depth selectivity of the microscope with a volume hologram pupil is also measured and found to vary significantly with recording parameters and lateral shift of the probe point source in object space. This experiment is modified to incorporate controlled levels of spherical aberration, where the effect on the depth selectivity is evaluated. A novel resolution target designed specifically for the evaluation of this imaging system is described and imaged. A flexible approach based on the 1st-order Born approximation is implemented to simulate all aspects of the imaging system with a multiplex volume hologram pupil. The simulation is then used to verify and expand upon the experimental results. A mathematical treatment of the nature of the anomalous apparent curvature of the diffraction image is performed, showing that a volume grating recorded in plane has weak out-of-plane spatial filtering behavior.
by Jonathan M. Watson.
S.M.
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Flewellen, James Lewis. "Digital holographic microscopy for three-dimensional studies of bacteria." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:94ff344b-51ec-41c5-a5f8-c579e16dccd7.
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Holography has the ability to render three-dimensional information of a recorded scene by capturing both the amplitude and phase of light incident on the recording medium. The application of digital camera technology and high-speed computing means digital holograms can be analysed numerically and novel applications can be found for this technology. This thesis explores the potential for both inline and off-axis digital holographic microscopy to study the three-dimensional swimming behaviour of bacteria. A high-magnification (225x) digital holographic microscope was designed and constructed with the ability to switch easily between inline and off-axis imaging modalities. Hardware aspects, in particular the illumination source, the choice of camera and data transfer rates, were considered. Novel strategies for off-axis holography combining dark field microscopy were designed and implemented. The localisation accuracy of the inline imaging modality was assessed by studying samples of polystyrene microspheres. The microscope is sensitive to stage drift on the order of angstroms per second and can successfully localise microspheres in dilute suspensions at least 100μm from the objective specimen plane. As a simple test of the capabilities of the microscope, the diffusion coefficient of a 0.5μm microsphere was found to be isotropic and consistent with the theoretical value. Amplitude and phase image reconstructions from the off-axis modality are demonstrated. High-magnification dark field off-axis holographic microscopy is shown to be superior to inline microscopy in localising 100nm gold nanoparticles. An artifact from our method of dark-field imaging, however, restricts the depth range to 15μm. A lower-magnification (45x) configuration of the microscope was used to study the 3D swimming behaviour of wild type Escherichia coli as a qualitative demonstration of the potential for this instrument in microbiological applications.
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Magalhães, Daniel Souza Ferreira. "Construção de telas holográficas e aplicações." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278163.
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Orientador: Jose Joaquín LunazziTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: A Tela holográfica é um elemento óptico difrativo gerado pela interferência de dois feixes de maneira a redistribuir convenientemente para um observador a luz que recebe com o objetivo de visualização de imagens sem óculos e com paralaxe. Neste trabalho descrevemos alguns métodos de obtenção de telas holográficas para aplicações em projeções com luz branca. As fundamentamos, analisamos os resultados obtidos, assim como descrevemos suas aplicações.
Abstract: Holographic screen is a difractive optical element generated by the interference of two beams in order to properly distribute to an observer the light it receives with the purpose of viewing parallax images without glasses. This work describes some methods for obtaining holographic screens looking forward applications with white light. We substantiate, analyze the results and describe their applications.
Doutorado
Ótica
Doutor em Ciências
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Nguyen, Krzysztof Quoc Khanh. "Characterisation of holographic projection as structured illumination in a Time-of-Flight based 3D imaging system." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9953.
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This thesis describes work on a novel 3D imaging system that successfully implements optical feedback and noise rejection mechanisms. The system is a combination of three relatively new technologies, namely, holographic projection, Time of Flight (ToF) ranging and Single Photon Avalanche Diode (SPAD) sensors. Holographic projection is used to provide structured illumination with optical feedback instead of more commonly used uniform illumination in similar imaging systems. It is obtained using a Ferro-electric Liquid Crystal on Silicon Spatial Light Modulator (FLCoS SLM). The structured illumination with optical feedback can be operated at up to 60 Hz with the current device, and has been shown to provide an average gain of about 1.56 in useful light levels. Alternatively, a gain over a limited area of up to a factor of 9 is possible with the current system. Time of Flight ranging is a method of choice for the system when depth estimation is concerned. It works even at very low light levels and allows for sub-centimetre depth resolution. ToF method was implemented using 20 MHz laser diode with 50 ps pulse duration and 200 mW peak power, as well as a SPAD sensor. The SPAD sensor consisted of a 32 32 array of 50 μm pixels, each with 10 bit Time to Digital Converter (TDC) with 50 ps timing resolution. Sensor pixels feature 100 Hz mean Dark Count Rate (DCR). The use of SPAD sensors with an adaptive sensing algorithm presented in this work has been demonstrated to reduce effective noise levels as seen by the sensor by a factor of 16. As a result, a significant gain in depth resolution can be achieved. The quantification of this gain is explained in more detail within this work. Furthermore, the work describes in detail system design, methodology of experimental procedure as well as different algorithms essential to the correct operation of the system. Significant amount of time is dedicated to diffraction pattern generation for the use in holographic projection, as well as modelling of photon detection in SPAD sensors and associated peak detection necessary to extract depth information from histograms of timed of photons. Moreover, the thesis discusses potential applications for the system based on the results of system characterisation presented in this work. The current state of the system suggests best suitability for gaming and machine vision applications. Finally, the work offers potential solutions to the practical issues that remain unresolved in the current system, alternatives for components used and paths for potential future development of the system proposed.
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Tian, Lei Ph D. Massachusetts Institute of Technology. "Phase-space representation of digital holographic and light field imaging with application to two-phase flows." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57789.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 125-133).
In this thesis, two computational imaging techniques used for underwater research, in particular, two-phase flows measurements, are presented. The techniques under study, digital holographic imaging and light field imaging, are targeted at different flow conditions. In low-density flows, particles and air bubbles in water can be imaged by a digital holographic imaging system to provide 3D flow information. In the high density case, both occlusions and scattering become significant, imaging through these partial occlusions to achieve object detection is possible by integrating views from multiple perspectives, which is the principle of light field imaging. The analyses on the digital holographic and light field imaging systems are carried out under the framework of phase-space optics. In the holographic imaging system, it is seen that, by tracking the Space bandwidth transfer, the information transformation through a digital holographic imaging system can be traced. The inverse source problem of holography can be solved in certain cases by posing proper priori constraints. As is in the application to two-phase flows, 3D positions of bubbles can be computed by well tuned focus metrics. Size statistical distribution of the bubbles can also be obtained from the reconstructed images.
(cont.) Light field is related to the Wigner distribution through the generalized radiance function. One practical way to sample the Wigner distribution is to take intensity measurements behind an aperture which is moving laterally in the field. Two types of imaging systems, the light field imaging and the integral imaging, realize this Wigner sampling scheme. In the light field imaging, the aperture function is a rect function; while a sinc aperture function in the integral imaging. Axial ranging through the object space can be realized by digital refocusing. In addition, imaging through partial occlusion is possible by integrating properly selected Wigner samples.
by Lei Tian.
S.M.
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Subramani, Dinesh. "The Diode Laser Source and the Spatial Light Modulator's Driver Electronics for Miniaturized Holographic 3D Imaging." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36409.
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The purpose of this thesis is to develop a low-cost, high power laser diode/fiber illumination system and to design the driver electronics of the spatial light modulator (SLM) for holographic, three dimensional (3D) imaging. A miniaturized laser diode/fiber/polarizing illumination system capable of 15mW of output at a wavelength of 690nm is designed, fabricated, and tested. The size limitations of various commercially available SLM drivers are described and the design to overcome them is suggested. The design describes in detail the timing considerations of the hardware interface and the psuedocode of the software interface between the host computer and the SLM. Experiments carried out to study the spatial uniformity of the SLM and the distortion due to the beam splitter on the structured output from the LIM are explained.Master of Science
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Crotty, Maureen. "Signal to Noise Ratio Effects on Aperture Synthesis for Digital Holographic Ladar." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1355245759.
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Clark, David C. "Digital Holographic Measurement of Nanometric Optical Excitation on Soft Matter by Optical Pressure and Photothermal Interactions." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4299.
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In this dissertation we use digital holographic quantitative phase microscopy to observe and measure phase-only structures due to induced photothermal interactions and nanoscopic structures produced by photomechanical interactions. Our use of the angular spectrum method combined with off-axis digital holography allows for the successful hologram acquisition and processing necessary to view these phenomena with nanometric and, in many cases, subnanometric precision. We show through applications that this has significance in metrology of bulk fluid and interfacial properties.
Our accurate quantitative phase mapping of the optically induced thermal lens in media leads to improved measurement of the absorption coefficient over existing methods. By combining a mathematical model describing the thermal lens with that describing the surface deformation effect of optical radiation pressure, we simulate the ability to temporally decouple the two phenomena. We then demonstrate this ability experimentally as well as the ability of digital holography to clearly distinguish the phase signatures of the two effects. Finally, we devise a pulsed excitation method to completely isolate the optical pressure effect from the thermal lensing effect.
We then develop a noncontact purely optical approach to measuring the localized surface properties of an interface within a system using a single optical pressure pulse and a time-resolved digital holographic quantitative phase imaging technique to track a propagating nanometric capillary disturbance. We demonstrate the method's ability to accurately measure the surface energy of pure media and chemical monolayers formed by surfactants with good agreement to published values. We discuss the possible adaptation of this technique to applications for living biological cell membranes.
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Brown, Andrew, and Hua Lee. "SYNTHETIC APERTURE GROUND PENETRATING RADAR IMAGING FOR NONDESTRUCTIVE EVALUATION OF CIVIL AND GEOPHYSICAL STRUCTURES." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607690.
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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaSynthetic-aperture microwave imaging with ground penetrating radar systems has become a research topic of great importance for the potential applications in sensing and profiling of civil and geophysical structures. It allows us to visualize subsurface structures for nondestructive evaluation with microwave tomographic images. This paper provides an overview of the research program, ranging from the formation of the concepts, physical and mathematical modeling, formulation and development of the image reconstruction algorithms, laboratory experiments, and full-scale field tests.
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Perfetti, Claire. "Particle manipulation in minichannels for enhanced digital holographic microscopy observation." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209283.
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The development of techniques targeting the manipulation of particles of differentsizes - mostly in the nano to millimeter scale - when dispersed in a carrier medium, is an increasingly important topic in many fields such as biotechnology,nanotechnology, medicine, biophysics and environmental monitoring and remediation. The underlying rationale for using such techniques stands in the sometimes compelling requirements of avoiding clogging as in micro/nano channel flows, of limiting sedimentation and wall interactions in particle/cell counting, of enhancing particle-surface interaction as in bio-sensing or of facilitating characterization and sorting as in bio-physical applications. Being developed in the frame of a Belgian national project devoted to the characterization and counting of pollutant in water media by digital holographic microscopy, this thesis tackles a peculiar class of particle manipulation techniques, commonly known as Focusing. The main goal of focusing is to avoid at best wall particle interactions and sedimentation, prevalent issues for dispersions owing in micro/mini-channels especially for applications such as optical characterization and counting.
The main attention was given to two flow focusing techniques - Hydrodynamic and Acoustic Focusing - for their wide range applicability and cost effectiveness. Hydrodynamic Focusing consists in controlling the position and spreading of the sample under investigation by means of a so-called sheath flow. A low-cost, nevertheless effective, prototype has been conceived, designed, manufactured and tested. It allowed for controlling the spreading of the sample stream and achieving a focusing ratio accounting for only 4% of the original stream width.
Acoustic Focusing takes advantage of the time-averaged pressure fields induced by the creation of standing waves in channels to manipulate and focus the dispersed particles. In the frame of this thesis, several devices have been developed using square cross section glass mini-channels. Aside from the cost-effectiveness, particles where focused in a somehow unexpected but high reproducible 3D matrix-like structure. A novel numerical model has also been implemented in order to study the conditions leading to the 3D structure formation. A good agreement between experimental and numerical results was found./Ce projet de thèse portant sur la manipulation de micro-particules dans des minicanaux s'inscrit dans le développement de cellules de flux pour des applications biologiques, qui est l'une des problématiques du projet HOLOFLOW, soutenu par
la région de Bruxelles Capitale. Les cellules de flux doivent permettre l'observation et la reconnaissance des micro-organismes vivants dans une large gamme de dimensions (de quelques microns à 1mm) avec la microscopie holographie digitale.
La problématique d'observation et de manipulation des microorganismes en flux est liée au clogging (bouchage) et à la sédimentation qui limitent la durée de vie des cellules d'observation. Ce projet de thèse s'inscrit dans cette problématique et propose deux axes d'étude pour limiter l'interaction entre organismes et canaux, la focalisation hydrodynamique, basée sur le guidage de flux, et la focalisation acoustique, basée sur la manipulation des particules.
La focalisation hydrodynamique est une technique basée sur l'injection différentiée de l'échantillon à observer et d'un fluide support. La différence des vitesses d'injection des flux permet de contrôler la dispersion des particules afin d'optimiser leur observation. Dans le cadre de cette thèse, un prototype à bas-coût a été développé et construit, permettant de focaliser les particules dans un faisceau jusqu'à 4% de leur faisceau incident.
La focalisation acoustique utilise la création d'une onde acoustique stationnaire afin de regrouper les particules en suspension au centre du canal. Au cours de cette thèse, plusieurs prototypes ont été réalisés, mettant en évidence la formation de motifs tridimensionnaux. Un model numérique a été spécialement développé afin d'étudier les conditions de génération de ces motifs, et de nombreuses expériences ont été menées afin de s'assurer de leur reproductibilité. Une bonne adéquation entre la position des particules mesurée et calculée numériquement a été démontrée.
Doctorat en Sciences de l'ingénieur
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Schaffert, Stefan [Verfasser], Stefan [Akademischer Betreuer] Eisebitt, and Christian [Akademischer Betreuer] Gutt. "Holographic imaging and time-resolved X-ray scattering on magnetic-domain systems / Stefan Schaffert. Gutachter: Stefan Eisebitt ; Christian Gutt. Betreuer: Stefan Eisebitt." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067387188/34.
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Blocher, Garth M. "Development of an Infrared Direct Viewer Based on a MEMS Focal Plane Array." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/901.
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"Thermal infrared (IR) imaging systems are widely used in medical, industrial, and defense applications. IR imaging systems utilize a lens to focus IR radiation onto a focal plane array (FPA) of IR detectors, which transduce the IR radiation from the scene into signals that can be further processed. In conventional IR imaging systems, electronic readout integrated circuitry (ROIC) is used to read out the information from the FPA, and computer signal processing allows for an IR image to be displayed on an electronic screen. However, the ROIC decreases the thermal isolation and sensitivity of the IR detectors in the FPA, and the computer processing and electronic display increase the cost, weight, and complexity of the IR imaging system. This thesis focuses on the development of an IR direct viewing system that does not require any ROIC, computer signal processing, or electronic display. This is accomplished through the use of microelectromechanical systems (MEMS) uncooled IR imaging detectors, which consist of arrays of bimaterial thermomechanical cantilever structures that tilt as a function of IR radiation from a scene. Other members of the WPI-ME/CHSLT group have previously shown that an interferometric optical readout mechanism based on digital holography and computer processing can eliminate the need for ROIC and be used to measure the nanometer scale tilt of the structures in a MEMS-based IR imaging system that was found to have a responsivity of 1.5 nm/K. However, these previously demonstrated results required significant computer processing and an electronic display. The hypothesis of the current work is that an optomechanical readout mechanism can be used to realize an IR direct viewer without the use of ROIC, computer signal processing, or an electronic display. Three optical readout mechanisms were identified for transducing the nanometer scale deformations of the MEMS structures in the FPA into a directly observable visible light image. Two of these, one using live holography and the other using Nomarski differential interference contrast (DIC), were based on interferometry, while the third, using reflectometry, was based on geometrical optics. The identified optical readout mechanisms were analytically evaluated based on the performance and perception of the human vision system (HVS), and preliminary experimental results were obtained using optical setups constructed for all three readout mechanisms. Based on the analytical and experimental investigations, reflectometry was selected as the most suitable readout mechanism for a direct viewer. A visible light camera was used with custom software to determine a temperature sensitivity of 137 mK for the reflectometry readout, and thermal images of scenes at human body temperature were demonstrated using limited computer processing. A false color, direct view, live IR imaging system was then demonstrated based on a two color reflectometry readout and the output was characterized with respect to the color differentiation sensitivity of the HVS. The system temperature sensitivity, based on the theoretical color differentiation sensitivity of a human observer, was found to be on the order of 10 K across a measuring range of roughly 400 °C, and objects with a temperature as low as approximately 150 °C were distinguishable. The advantages and limitations of the developed IR imaging system are identified and recommendations for further developments and future work are provided."
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Barszczak, Sardinha Anna Luiza. "Coherent imaging of nano-objects with ultra-short X-ray pulses." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX006/document.
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L'utilisation des rayons X est indispensable pour obtenir la résolution spatiale de la dizaine de nanomètres. La durée de ces flashs va de la dizaine de femtosecondes (1 fs =10-15 s) à la centaine d'attosecondes (1as=10-18 s). Durant ce laps de temps, les nano-objets n'ont pas le temps d'évoluer, assurant l'obtention d'une image précise. En excitant les nano-objets entre deux flashs de rayons X, il est alors possible de suivre sont évolution temporelle et ainsi de réaliser un « film » de son évolution suite à une excitation. Cette information est extrêmement importante car elle permettra d'identifier les états structuraux intermédiaires des nano-objets qui sont connus comme étant les plus importants pour comprendre leur pouvoir réactionnel.Ce genre d'études vient uniquement de débuter dans le monde en raison de l'apparition très récente des sources de rayons X suffisamment brèves et intenses pour réaliser ce genre d'images. La source de référence est un laser dit à « électrons libres » (LEL) dont il existe trois exemplaires au monde, en Allemagne, aux USA et au Japon. Le faible nombre d'exemplaires provient du coût extrêmement élevé de cette machine. Depuis plusieurs années, nous avons montré au LOA que les lasers pouvaient produire un rayonnement X femtoseconde et suffisamment intense pour réaliser des images de nano-objets avec des résolutions spatiales et temporelles équivalentes à celles obtenues sur LEL.La présente thèse a etait construite autour de trois phases : réalisation d'une source de rayons X polarisés circulairement, réalisation d'un nouveau système plus performant d'imagerie, et test sur des échantillons possédants des nano-structures dont la vitesse d'évolution après excitation est prévue aux environs de 100 fs. Ces études ont eu lieu ao LOA, LCLS, Laboratoire de Chimie-Physique, Matière et Rayonnement (LCPMR) et le CEA de Saclay et BESSY-II en Alemagne. Ils ont permis de acquérir une forte expertise en imagerie nanométrique basée sur la nouvelle technique que nous avons développéThe use of X-rays is fundamental to obtain a spatial resolution in the order of the dozen of nanometers. The duration of the flashes of radiation is placed between the dozen of femtoseconds (1 fs =10-15 s) to the hundreds of attoseconds (1as=10-18 s). During this time frame nano-objects are static in time, image wise it translates as a precise image. Exciting these nano-objects with flashes of X-ray beams it is possible to follow its temporal evolution and record a "movie" of the evolution due to excitation. This type of information is extremely important since it can allow the identification of intermediary structural states and therefore attaining a better understanding of their reactional power.This type of studies it is making its debut in the scientific community due to the recent development of ultra-fast and intense X-ray sources needed to perform this type of imaging. The referenced source is a free electron laser (FEL) and there are only tree of them in the world nowadays. One in Germany, one in the USA and one in Japan. The small amount of FELs is mainly due to its elevated costs. From some years the LOA has shown that lasers can also provide an X-ray beam in the femtosecond region and intense enough to produce images of nano-objects with equivalent temporal and spatial resolutions.This present thesis was built in tree phases: realization of an X-ray laser source, circularly polarized; realization of a new improved imaging system and testing of the nano-samples possessing nano-structures. These nano-structures have a velocity of evolution after excitation in the range of 100 fs. These studies have had place at LOA, LCLS, Laboratoire de Chimie-Physique, Matière et Rayonnement (LCPMR), the CEA de Saclay, BESSY-II in Germany. These cooperations have insured a specific training and expertise in the world of nanometric imaging based on the new technique developed during this work
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Sorensen, Thomas J. "Inverse Scattering Image Quality with Noisy Forward Data." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2541.pdf.
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Ďuriš, Miroslav. "Zobrazení objektu v rozptylujícím prostředí kombinací signálu balistických a rozptýlených fotonů v koherencí řízeném holografickém mikroskopu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-392845.
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Diplomová práca sa zaoberá kvantitatívnym fázovým zobrazovaním objektov umiestnených za rozptyľujúcim prostredím v koherenciou riadenom holografickom mikroskope. Tento mikroskop umožnuje zobrazovať s úplne nekoherentným osvetlením vzorky, čo vyvoláva efekt koherenčnej brány. Koherenčná brána je veľmi dôležitá vlastnosť zobrazovacieho systému umožňujúca separáciu balistických a rozptýlených fotónov, jej dôkladnému vysvetleniu je venovaná značná časť práce. Ďalej sú prezentované základy teórie zobrazenia v koherenciou riadenom holografickom mikroskope. Tie sú využité v závere práce pri interpretácii experimentálnych výsledkov. Cieľom práce je navrhnúť metódu pre pozorovanie fázových objektov v rozptyľujúcich prostrediach a experimentálne túto metódu overiť. Na základe analytických výsledkov a predchádzajúceho výskumu je navrhnutá nová metóda, ktorá je ďalej overovaná pomocou rôzne komplexných vzoriek. Je založená na zázname viacerých obrazov s rôznym posunutím referenčného poľa. Každý posun korešponduje so zobrazovaním pomocou inej skupiny fotónov. Je možné vytvoriť syntetický obraz so zlepšenou kvalitou sčítaním jednotlivých obrazov získaných z interferencie balistických alebo rozptýlených fotónov. Experimenty s rôzne komplexnými vzorkami poskytujú náhľad na obmedzenia prezentovanej metódy.
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Čolláková, Jana. "Průtokové komůrky pro mikroskopii živých buněk." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229859.
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The perfusion chamber for long term observing of live cells by the means the Coherence-Controlled Holographic Microscope (CCHM) was designed. CCHM was built and designed at the Laboratory of the optical microscopy at the Institute of Physical Engineering, Brno University of Technology. CCHM can quantitatively evaluate dynamical changes inside live cells thanks to the quantitative information about phase shift in each pixel of the image. In order to demonstrate advantages of CCHM experimentally, it is important to keep the live cells in the good conditions. This is made by adding the fresh cultivation medium for studied cells directly in the microscope. In contrast to the stationary chamber the perfusion chamber allows both the cultivation medium exchange and the application of biological reagents without the necessity of removing the chamber from the microscope. Therefore we can study the vital signs of cells before and after the application of reagents. An original perfusion system with accessories compatible with CCHM was designed. The design is based on the previously published perfusion system solutions that are referred to in this thesis. The flow characteristics and medium exchange process was discussed and a modification of the internal geometry, based on numerical simulations, was introduced. The applicability of this perfusion chamber has been proven for the CCHM and even for different types of microscopes. The reactions of tumor and epithelial cells during the change of the environment from the cultivation medium to the physiologically solution were studied.
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Slabý, Tomáš. "Koherencí řízený holografický mikroskop nové generace." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234255.
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This doctoral thesis deals with design of a new generation of coherence-controlled holographic microscope (CCHM). The microscope is based on off-axis holographic configuration using diffraction grating and allows the use of temporally and spatially incoherent illumination. In the theoretical section a new optical configuration of the microscope is proposed and conditions for different parameters of the microscope and its optical components are derived. The influence of different sources of noise on phase detection sensitivity is studied. In the next section design of experimental setup is described and automatable adjustment procedure is proposed. Last section describes experimental verification of the most important optical parameters of the experimental setup. When compared to previous generation of CCHM, the newly proposed configuration uses infinity-corrected objectives and common microscope condensers, allows more space for the specimens, eliminates the limitation of spectral transmittance and significantly simplifies the adjustment procedure so that automation of this procedure is possible.
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Brasiliense, Vitor. "Opto-Electrochemical Methods for Imaging the Reactivity of Individual Nanoparticles." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC283/document.
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Dans ce travail, plusieurs méthodes opto-électrochimiques ont été développées et appliquées à l’étude de systèmes chimiques à l’échelle de l’objet individuel. Du coté optique,l’holographie et la spectroscopie visible ont été associées à la super localisation pour pousser l’applicabilité de ces techniques au-delà de la limité imposée par la diffraction.Des techniques nanoélectrochimiques, comme les impacts stochastiques et l’utilisation de nanoelectrodes, complètent cette étude en renseignant sur la réactivité et sur les étapes de transfert d’électrons. Ces études couplées caractérisent ainsi les phénomènes chimiques de façon bien plus complète. Il est montré que cette caractérisation à la fois chimique et optique est en fait essentielle pour pouvoir comprendre le fonctionnement des systèmes nano chimiques in loco.En démarrant par des réactions modèle, comme l’oxydation de l’argent, la complexité des systèmes étudiés est progressivement augmentée, éclairant des phénomènes de transport,d’agrégation, ainsi que des transformation redox et de catalyse sur des matériaux complexes et mal définis tel que les oxydes de métaux de transition (cobalt)A number of coupled optical and electrochemical single particle techniques are employed for investigating a variety of chemical systems at the level of individual objects.On the optical side, holography and visible spectroscopy are imbued with superlocalization principles pushing the applicability of these techniques down to sub-diffraction levels. Nanoelectrochemical techniques such as stochastic impacts and nanoelectrodes are used to complement this information, providing a much more complete characterization of the phenomena.It is shown that this dual optical and electrochemical single particle characterizationis actually crucial to understand complex nano chemical systems in loco. Starting frommodel reactions, such as Ag oxidation, the complexity of the studied phenomena and systems is progressively increased, as light is shed on transport phenomena, aggregation,as well as redox transformations and catalysis on complicated materials such as ill-defined transition metal (cobalt) oxides
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Flasseur, Olivier. "Object detection and characterization from faint signals in images : applications in astronomy and microscopy." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSES042.
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La détection et la caractérisation d’objets dans des images à faible rapport signal sur bruit est un problème courant dans de nombreux domaines tels que l’astronomie ou la microscopie. En astronomie, la détection des exoplanètes et leur caractérisation par imagerie directe depuis la Terre sont des sujets de recherche très actifs. Une étoile cible et son environnement proche (abritant potentiellement des exoplanètes) sont observés sur de courtes poses. En microscopie, l’holographie en ligne est une méthode de choix pour caractériser à faibles coûts les objets microscopiques. Basée sur l’enregistrement d’un hologramme, elle permet une mise au point numérique dans n’importe quel plan du volume 3-D imagé. Dans ces deux applications cibles, le problème est rendu difficile par le faible contraste entre les objets et le fond non stationnaire des images enregistrées.Dans cette thèse, nous proposons un algorithme non-supervisé dédié à la détection et à la caractérisation d’exoplanètes par une modélisation statistique des fluctuations du fond. Cette méthode est basée sur une modélisation de la distribution statistique des données à une échelle locale de patchs, capturant ainsi leur covariances spatiales. Testé sur plusieurs jeux de données de l’imageur haut-contraste SPHERE opérant au Très Grand Télescope Européen, cet algorithme atteint de meilleures performances que les méthodes de l’état de l’art. En particulier, les cartes de détection produites sont stationnaires et statistiquement fondées. La détection des exoplanètes peut ainsi être effectuée à probabilité de fausse alarme contrôlée. L’estimation de la distribution d’énergie spectrale des sources détectées est également non biaisée. L’utilisation d’un modèle statistique permet également de déduire des précisions photométriques et astrométriques fiables. Ce cadre méthodologique est ensuite adapté pour la détection de motifs spatialement étendus tels que les motifs de diffraction rencontrés en microscopie holographique qui sont également dominés par un fond non-stationnaire. Nous proposons aussi des approches robustes basées sur des stratégies de pondération afin de réduire l’influence des nombreuses valeurs aberrantes présentes sur les données réelles. Nous montrons sur des vidéos holographiques que les méthodes de pondération proposées permettent d’atteindre un compromis biais/variance. En astronomie, la robustesse améliore les performances de détection, en particulier à courtes séparations angulaires, où les fuites stellaires dominent. Les algorithmes développés sont également adaptés pour tirer parti de la diversité spectrale des données en plus de leur diversité temporelle, améliorant ainsi leurs performances de détection et de caractérisation. Tous les algorithmes développés sont totalement non-supervisés: les paramètres de pondération et/ou de régularisation sont estimés directement à partir des données. Au-delà des applications considérées en astronomie et en microscopie, les méthodes de traitement du signal introduites dans cette thèse sont générales et pourraient être appliquées à d’autres problèmes de détection et d’estimationDetecting and characterizing objects in images in the low signal-to-noise ratio regime is a critical issue in many areas such as astronomy or microscopy. In astronomy, the detection of exoplanets and their characterization by direct imaging from the Earth is a hot topic. A target star and its close environment (hosting potential exoplanets) are observed on short exposures. In microscopy, in-line holography is a cost-effective method for characterizing microscopic objects. Based on the recording of a hologram, it allows a digital focusing in any plane of the imaged 3-D volume. In these two fields, the object detection problem is made difficult by the low contrast between the objects and the nonstationary background of the recorded images.In this thesis, we propose an unsupervised exoplanet detection and characterization algorithm based on the statistical modeling of background fluctuations. The method, based on a modeling of the statistical distribution of patches, captures their spatial covariances. It reaches a performance superior to state-of-the-art techniques on several datasets of the European high-contrast imager SPHERE operating at the Very Large Telescope. It produces statistically grounded and spatially-stationary detection maps in which detections can be performed at a constant probability of false alarm. It also produces photometrically unbiased spectral energy distributions of the detected sources. The use of a statistical model of the data leads to reliable photometric and astrometric accuracies. This methodological framework can be adapted to the detection of spatially-extended patterns in strong structured background, such as the diffraction patterns in holographic microscopy. We also propose robust approaches based on weighting strategies to reduce the influence of the numerous outliers present in real data. We show on holographic videos that the proposed weighting approach achieves a bias/variance tradeoff. In astronomy, the robustness improves the performance of our detection method in particular at close separations where the stellar residuals dominate. Our algorithms are adapted to benefit from the possible spectral diversity of the data, which improves the detection and characterization performance. All the algorithms developed are unsupervised: weighting and/or regularization parameters are estimated in a data-driven fashion. Beyond the applications in astronomy and microscopy, the signal processing methodologies introduced are general and could be applied to other detection and estimation problems
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Corman, Ramona. "2D/3D lensless imaging : prototype and applications." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS042.
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L’imagerie biologique a réalisé des progrès significatifs durant les dernières décennies. Les récentes innovations portent sur la manipulation et la visualisation de cellules uniques avec une résolution spatiale de l’ordre du nanomètre. Une technologie d’imagerie récente, l’imagerie «sans lentille », est particulièrement prometteuse car elle combine une bonne résolution spatiale, un champ de vision étendu, une simplicité d’utilisation, un coût abordable et la possibilité de travailler sur des échantillons exempts de marqueurs spécifiques. En imagerie sans lentille, le système optique classiquement utilisé pour constituer l’image de l’échantillon est remplacé par des algorithmes informatiques qui s’appuient sur les propriétés de cohérence spatiale de la lumière. Dans cette thèse, deux approches différentes de microscopie sans lentille sont considérées : l’holographie numérique en ligne et l’holographie par transformée de Fourier.Deux prototypes d’imagerie, construits selon ces principes, sont présentés. Ils offrent une résolution de l’ordre du micron, ainsi que la possibilité de retrouver les informations relatives à l’amplitude spatiale et à la phase du champ optique. Cela permet la réalisation de reconstructions pseudo-3D d’objets volumétriques à partir d’un unique hologramme. Les deux dispositifs ont d’abord été caractérisés avec des échantillons de référence. Par la suite, des expériences d’applications ont été testées pour estimer la capacité des dispositifs à répondre à des problématiques concrètes dans le domaine de la biologie, grâce à la haute résolution, l’imagerie en temps réel et la reconstruction 3D.L’objectif de cette thèse est également de développer une nouvelle plateforme qui intègre, dans une puce microfluidique, d’une part un système permettant la manipulation de cellules par diélectrophorèse, et d’autre part un masque optique pour la visualisation des cellules par imagerie sans lentille. Le principe de fonctionnement est basé sur le déplacement des cellules en milieu liquide et la séparation des cellules dans le champ de vision du microscope en utilisant un champ électrique induit par des électrodes spécifiques. Le masque optique permet de définir le champ de vision du microscope et de créer les faisceaux de référence nécessaires pour l’imagerie par holographie par transformée de Fourier. Le principal avantage de ce système électro-optique pour l’imagerie cellulaire réside dans sa capacité à fournir une plateforme d’imagerie compacte qui regroupe précision et sensibilité. Les champs d’applications de cette plateforme sont variés. Une application concrète qui découle immédiatement des premières expériences présentées dans ce manuscrit serait l’analyse du comportement des cellules et de leurs modifications morphologiques lors d’un processus électrochimique de diélectrophorèse.L’un des challenges majeurs dans le domaine de la microscopie est de réduire les coûts de fabrication. Les deux types de microscopes sans lentille présentés dans cette thèse visent à introduire dans le monde scientifique des outils d’imagerie permettant d’obtenir une haute résolution à un faible coût et sans marquage. Par ailleurs, la puce microfluidique est une première démonstration de plateforme intégrée pour l’analyse des cellules en temps réel dans un dispositif de type « Lab-on-a-chip »Biological imaging has made tremendous progresses these last decades. The latest developments concern manipulating and imaging single cells with nanometer spatial resolutions. A recent category of imaging techniques, called lensless microscopy, are very promising because they combine very good spatial resolutions in a large field-of-view, simplicity of use and low cost, while operating on label free samples. In this thesis two different lensless approaches are considered: digital in-line holography (DILH) and Fourier transform holography (FTH). In lensless imaging, the usual optical system used to form the sample’s image are remove and replace by numerical algorithms using the light spatial coherence properties.Two imaging prototypes, built on these principles, are presented. They offer (sub ) micrometer scale resolutions, and offer the possibility to retrieve both spatial amplitude and phase information of the optical field. This allows to achieve pseudo-3D reconstruction of volumetric objects from a single 2D hologram. Both devices were first characterized with reference samples. In a second step, real applications, relevant to selected biological problems, were performed to assess the devices’ performances towards high resolution, real time imaging and 3D.This thesis objective is also to develop a new platform directly integrating in a single chip a microfluidics system for biological cell handling by dielectrophoresis and an optical mask for cell visualization by lensless microscopy. Its working principle is based on cell transport in a liquid media by microfluidics, cell separation in the microscope field of view by the electric field induced by specific electrodes, and simultaneous cell imaging by Fourier Transform Holography. The main advantage of such coupled electro-optical system for cell imaging and analysis are the improved control, the precision and sensitivity regarding cell morphology all together merged in a compact imaging platform. The capability of the platform can be extended to analysis of cells’ behavior and morphologic deviation during the electrochemical processes of DEP.A major challenge in microscopy field is to reduce the production costs. The two types of lensless microscopy presented in this thesis aims to introduce new imaging tools that allows scientists to obtain low-cost high-resolution images in label-free conditions. Additionally, the microfluidics chip is a first demonstration of a new integrated platform for cell live analysis into a single Lab-on-a-chip device
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Laudereau, Jean-Baptiste. "Acousto-optic imaging : challenges of in vivo imaging." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066414/document.
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Les tissus biologiques sont des milieux fortement diffusant pour la lumière. En conséquence, les techniques d'imagerie actuelles ne permettent pas d'obtenir un contraste optique en profondeur à moins d'user d'approches invasives. L'imagerie acousto-optique (AO) est une approche couplant lumière et ultrasons (US) qui utilise les US afin de localiser l'information optique en profondeur avec une résolution millimétrique. Couplée à un échographe commercial, cette technique pourrait apporter une information complémentaire permettant d'augmenter la spécificité des US. Grâce à une détection basée sur l'holographie photoréfractive, une plateforme multi-modale AO/US a pu être développée. Dans ce manuscrit, les premiers tests de faisabilité ex vivo sont détaillés en tant que premier jalon de l'imagerie clinique. Des métastases de mélanomes dans le foie ont par exemple été détectées alors que le contraste acoustique n'était pas significatif. En revanche, ces premiers résultats ont souligné deux obstacles majeurs à la mise en place d'applications cliniques.Le premier concerne la cadence d'imagerie de l'imagerie AO très limitée à cause des séquences US prenant jusqu'à plusieurs dizaines de secondes. Le second concerne le speckle qui se décorrèle en milieu vivant sur des temps inférieurs à 1 ms, trop rapide pour les cristaux photorefractif actuellement en palce. Dans ce manuscrit, je propose une nouvelle séquence US permettant d'augmenter la cadence d'imagerie d'un ordre de grandeur au moins ainsi qu'une détection alternative basée sur le creusement de trous spectraux dans des cristaux dopés avec des terres rares qui permet de s'affranchir de la décorrélation du speckleBiological tissues are very strong light-scattering media. As a consequence, current medical imaging devices do not allow deep optical imaging unless invasive techniques are used. Acousto-optic (AO) imaging is a light-ultrasound coupling technique that takes advantage of the ballistic propagation of ultrasound in biological tissues to access optical contrast with a millimeter resolution. Coupled to commercial ultrasound (US) scanners, it could add useful information to increase US specificity. Thanks to photorefractive crystals, a bimodal AO/US imaging setup based on wave-front adaptive holography was developed and recently showed promising ex vivo results. In this thesis, the very first ones of them are described such as melanoma metastases in liver samples that were detected through AO imaging despite acoustical contrast was not significant. These results highlighted two major difficulties regarding in vivo imaging that have to be addressed before any clinical applications can be thought of.The first one concerns current AO sequences that take several tens of seconds to form an image, far too slow for clinical imaging. The second issue concerns in vivo speckle decorrelation that occurs over less than 1 ms, too fast for photorefractive crystals. In this thesis, I present a new US sequence that allows increasing the framerate of at least one order of magnitude and an alternative light detection scheme based on spectral holeburning in rare-earth doped crystals that allows overcoming speckle decorrelation as first steps toward in vivo imaging
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Maršíková, Barbora. "Trojrozměrné zobrazování v holografickém mikroskopu pomocí koherenční brány." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-392840.
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Tato diplomová práce se zabývá výzkumem na téma vlivu prostorové koherence osvětlení. Účelem je určit schopnost osové lokalizace při zobrazení Koherencí řízeným holografickým mikroskopem (CCHM) v závislosti na různé prostorové koherenci světelného zdroje. Osová lokalizace je v tomto případě zkoumána jako kvalita rozlišení drobných detailů trojrozměrného vzorku, umístěných nad sebou. Teorie zobrazení holografickým mikroskopem a teorie rozptylu v nehomogenních prostředích je shrnuta v první části práce, v rozsahu nutném pro pochopení části praktické. Základní princip fungování mikroskopu a přesný popis jeho uspořádání je zde podrobně popsán. Proběhl mechanický návrh stavební úpravy mikroskopu tak, aby bylo možno využívat kondenzorovou optiku s vysokou numerickou aperturou a omezenými optickými vadami. Několik různých přístupů, které by mohly vést ke zlepšení zobrazovacích vlastností mikroskopu, bylo navrženo a vyzkoušeno a jsou zde popsány i s jejich výhodami a nevýhodami. Pro experimentální část práce byl vyroben modelový vzorek. Závislost osové lokalizace na prostorové koherenci osvětlení byla demonstrována pomocí simulace a následně ověřena experimentálně, pozorováním vyrobeného modelového vzorku. Experimentální výsledky potvrzují základní principy vycházející ze zmíněné teorie. Na závěr jsou navržena možná vylepšení, pro budoucí zpřesnění výsledků.
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Vašíček, David. "Fluorescenční zobrazovací techniky v multimodálním holografickém mikroskopu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231466.
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The diploma thesis deals with the registration of images taken with the multimodal holographic microscope (MHM). The summary covers the fluorescent and holographic microscopy, and the multimodal holographic microscope combining both these microscopy types. Every pair of the images needs to be aligned in order to gain new information by combining both image types. The thesis contains an algorithm that registers images by phase correlation as well as a process created in MATLAB in accordance with the algorithm. The most important procedure parameters’ influence on the registration success is described and the results are annotated.
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Křížová, Aneta. "Koherencí řízený holografický mikroskop ve výzkumu životního cyklu buňky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230277.
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The goal of this diploma thesis was using of a coherence-controlled holographic microscope in cell’s life research. A brief history of interference microscopy and it’s applications in biology is described. Also other microscopy techniques routinely used for transparent objects imaging are mentioned and the biology of cell’s life cycle briefly explained. Characteristics describing the shape of a cell were proposed and tested with respect to identification of particular phases of its life cycle. The method of dynamic phase differences was modified in order to distinguish the internal motion of cell’s mass from the movement of the whole cell. Selected characteristics were used to evaluate observations carried out with the holographic microscope and the possibilities of their further applications were depicted. In conclusion, obtained findings were summarized and modifications of microscope construction as well as data-processing software were suggested.
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Škrabalová, Denisa. "Holografický modul pro světelnou mikroskopii." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402635.
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The new arrangement of the off-axis holographic module, which is using polarizationactive diffraction grating divides signal into reference and subject wave of an interferometer based on their polarization. However, current design of the module does not have a possibility to tune a length of the optical paths. Thus the inability to tune optical paths leads to a reduced quality of interference structure during observation of biological samples. The current module is only suitable for technical applicating due to this limitation. Possibility of tuning branches is key step in biological applications. Therefore a new computer-controlled module is created in order to enable use for biological samples.
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Pratsch, Christoph. "New methods for high resolution 3D imaging with X-rays." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19238.
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In der Arbeit haben wir die Grenzen der weit verbreiteten tomographischen
Rekonstruktion von 3D-Proben mittels Transmissionsröntgenmikroskopie charakterisiert.
Wir zeigen, dass die 3D-Auflösung mit diesem Ansatz durch die Schärfentiefe
begrenzt ist. Zur Untersuchung von Alternativen führten wir Simulationen
zur Bildentstehung in einem konfokalen Röntgenmikroskop und einem FIB-SXM
durch. Wir zeigen, dass FIB-SXM ein vielversprechender Ansatz ist, der eine isotrope
3D-Aulösung um die 10 nm erreichen kann und zusätzlich ein drastisch
verbessertes Signal-Rausch-Verhältnis bieten könnte. Wir stellen auch eine neue
Holographiemethode vor, die sich für Vollfeldabbildungen mit kurzen kohärenten
Röntgenpulsen als vorteilhaft erweisen und neue Einsichten in die ultraschnelle
Physik liefern könnte.We have characterized the limitations of the most powerful and widely used 3D X-ray imaging approach, transmission X-ray microscopy with tomographic reconstruction. We show that 3D resolution in this approach is limited by the depth of field. To investigate alternatives, we perform simulations of a confocal transmission X-ray microscope and a FIB-SXM. We show that FIB-SXM is a very promising approach that could o er 3D isotropic resolution at 10 nm with dramatically improved signal to noise. We also introduce a new holography method that could prove bene cial for full eld imaging with short coherent X-ray pulses and yield new insights into ultrafast physics.
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Whitcombe, Michael James. "Red-sensitive imaging systems for holography." Thesis, Royal Holloway, University of London, 1987. http://repository.royalholloway.ac.uk/items/93c5198a-27d2-4c1d-ba1b-744bdc04fac0/1/.
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The primary objective of the work described in this thesis was to devise a red-sensitive photoresist imaging process for use in the replication of diffraction optics. In the introduction the chemistry of conventional photopolymer systems and photoresists used for holographic recording and the fabrication of diffraction gratings and diffracting optical elements is reviewed. The limitations of commercially available photoresist systems, particularly for applications requiring the use of red light are discussed. A polymer system has been investigated which could be imaged by photochemically generated free radicals, followed by a simple aqueous development procedure as required by the original specification. The polymer chosen for study was a copolymer of methyl methacrylate, methacrylic acid and 2-hydroxyethyl methacrylate. This was derivatized using methacryloyl chloride or methacrylic anhydride in order to introduce cross-linkable units to the polymer backbone. Polymers have been characterized by a number of techniques and the effect of varying composition on aqueous base solubility has been thoroughly studied. Various methods of derivatization have been employed. The ease of imaging has been found to be very sensitive to both the composition of the polymer and the extent of functionalization. High quality images have been obtained from this polymer using an organic solvent developer. Imaging experiments have been carried out on thin films of the photopolymer coated on glass using phenylazotriphenylmethane (PATM) as photoinitiator. Good images of 100 lines permillimetre (1 mm-1) have been recorded by contact printing. Interferometry has been used to demonstrate that interference patterns having 600 and 1200 1 mm-1 can be recorded using this polymer with PATM as initiator, exposed to an argon ion laser operating at 458nm. A number of two component photoredox initiator systems have been investigated, the light absorbing species of such systems being a dye such as methylene blue or certain cyanine dyes. The second component of these initiators may be an aryl sulphinate salt, a 1,3-diketone or some alkyl sulphides. The red light-initiated phatopolymerization of acrylamide has been demonstrated using some of these initiators and a low resolution photopolymer image has been recorded using Azure A and perinaphth-1,3-indandione as the photoinitiator system. This polymer can, in principle, produce images over a wide range of wavelengths depending on the nature of the initiator used.
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Duckworth, Thomas Andrew. "Fourier transform holography for magnetic imaging." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/16152.
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State-of-the art Fourier transform holography (FTH) techniques use x-ray magnetic circular dichroism (XMCD) as a contrast mechanism for element-specfi c imaging of magnetic domains. With the soft x-ray Nanoscience beamline at Diamond Light Source in the UK, and the Dragon beamline at the European Synchrotron Radiation Facility (ESRF) in France, the possibility of new methods to study nanostructured magnetic systems has been demonstrated. The ability to record images without the use of lenses, in varying magnetic fi elds and with high spatial resolution down to 30 nm has been used to study in-plane magnetism of 50 nm thin permalloy (NiFe alloy) nanoelements. The holographic technique used extended reference objects rather than conventional pinhole references, which allowed a high flexibility on the direction of magnetisation that is probed. The element specific nature of the imaging, with the additional choice in the directions of magnetisation that are probed has been used to study dipolar interactions in a hard/Ta/soft [Co/Pt]30/Ta/Py multi-layered system. Images of the out-of-plane magnetised domains of [Co/Pt]30 were found to bare strong spatial resemblance to the in-plane domains of the permalloy. The domain structure is thought to be magnetostatically imprinted into permalloy during the growth stage of the lm, where stray elds generated by the adjacent Co/Pt multilayer influence the formation of domains in the permalloy. Strong resemblance between the two layers could be found at remanence within a pristine sample, however the similarities disappear after the sample was exposed to a saturating magnetic field. This disagreed with micromagnetic simulations performed in The Object Oriented MicroMagnetic Framework (OOMMF) program, and an explanation for the observations has been sought in the growth process of the multi-layered fi lm, with conditions that are diffi cult to recreate in the model. Optical holography has been used for preliminary insight into implementing a method of FTH in a reflective geometry at soft x-rays wavelength. With scattering chambers at BESSY II in Germany and at the Stanford Synchrotron Radiation Lightsource (SSRL) in California the possibility of reducing scattered noise in a hologram recorded in a reflective geometry has been investigated. Studies into specular and dif use reflections have been performed optically however the use of extended references alone may alleviate the current problem at x-ray wavelengths which lie in the weak signal given by a reflective point-like reference source.
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Marín, Garcia Jordi. "Off-axis holography in microwave imaging systems." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/285129.
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En las pasadas décadas, la investigación en tecnología de terahercios fue únicamente motivada por instrumentación para los campos de astrofísica y ciencias de la tierra. La principal línea de investigación de estos campos comprende la detección, identificación y mapeo mediante espectroscopia molecular de bandas de emisión y absorción de gases a baja presión. Este campo fue el mayor foco de desarrollo que permitió en primer lugar el desarrollo de instrumentación y tecnología a bandas de terahercios. En contraposición con su uso en campos científicos, la radiación de terahercios es una de las bandas de radio-frecuencia menos usadas en el ámbito comercial. La escasez de fuentes, sensores, sub-sistemas e instrumentos ha dificultado en los últimos años la proliferación de aplicaciones para un mayor público de consumo. La combinación de los últimos avances tecnológicos provenientes del campo científico, así como el descubrimiento de nuevas aplicaciones ha despertado de nuevo el interés por este campo, lo que ha supuesto un nuevo impulso económico para el desarrollo a estas frecuencias tanto a nivel público como privado.
Además del mencionado interés científico, la radiación de terahercios tiene características muy atractivas como por ejemplo una buena resolución espacial (comparada con menores frecuencias), penetración en materiales, capacidades espectroscópicas, absorción por humedad y niveles bajos de energía.
El trabajo desarrollado en esta tesis es parte de un proyecto de investigación a nivel nacional Español denominado Terasense. El interés principal de este proyecto es equipar las instituciones de investigación académicas con un nuevo conjunto de instrumentación y capacidades para poder desarrollar proyectos en el estado del arte en el campo de ondas milimétricas y sub-milimétricas.
El objetivo principal de esta tesis es explorar la viabilidad de sistemas de imagen en microondas y ondas milimétricas basados en técnicas holográficas mediante medidas de intensidad. En este documenta se estudia principalmente el uso de la técnica holográfica con referencia desplazada. No solo desde un punto de vista teórico sino especialmente desde un punto de vista experimental y práctico. En la tesis, diferentes experimentos y dispositivos son simulados, diseñados e implementados. La ida y vuelta entre software y hardware ha permitido la creación de un marco de desarrollo para el test de las diferentes técnicas de imagen estudiadas. El rango de frecuencia escogido como meta para este proyecto es la banda de frecuencia W (75-110 GHz). Sin embargo, muchos experimentos han sido desarrollados primero en banda X (8-12 GHz) para desarrollar la experiencia necesaria requerida para trabajar a frecuencias superiores en el rango de las ondas milimétricas.In past decades research in terahertz technology was solely motivated by instruments for topics such as astrophysics, planetary and earth sciences. Molecular line spectroscopy detection, identification and mapping of thermal emission and absorption signatures from low pressure gases comprised the main focus for most scientific requirements and motivated the development of terahertz instrumentation and technology. In spite of the scientific contributions of terahertz radiation, its spectrum is still one of the least used electromagnetics bands in commercial use. The unavailability of sources, sensors, sub-systems and instruments has been a cumbersome issue over the past years for its wide-spread use in commercial instrumentation. The combination of technological advances coming from the space-based community, along with the emergence of new applications, have managed to drive again the interest from both public and private sectors which has renown and skyrocketed the funding and research in terahertz applications. Aside from the aforementioned scientific interest, terahertz radiation has appealing characteristics such as good imaging resolution (as compared to lower frequencies), material penetration, spectroscopic capabilities, water absorption and low energy levels. The work of this thesis is part of a Spanish national research project called Terasense. The main focus of the project is to equip national academic research institutions with a completely new set of instrumentations and capabilities in order to advance towards the current state of the art in millimeter and sub-millimeter wave technologies. The main objective of this thesis is to explore the viability of microwave and millimeter-wave imaging systems based on intensity-only holographic techniques. This dissertation is mostly focused on the Off-Axis Holography technique. Not only from a theoretical perspective but specially from an actual implementation standpoint. In order to do so, different experimental setups and devices have been designed and manufactured. Iteration between hardware and software has created a framework for devising and testing different imaging techniques under consideration. The frequency range W-Band (75-110 GHz) has been chosen as the main goal for all systems under study, however different setups will first be constructed, characterized and tested at X-Band (8-12 GHz) in order to build up the expertise required to work at millimeter-wave frequencies.
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Parshall, Daniel. "Phase imaging digital holography for biological microscopy." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000285.
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Puyo, Léo. "Application clinique de l'holographie laser Doppler en ophtalmologie." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLET022.
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Cette thèse porte sur l'introduction de l'holographie laser doppler (LDH) au domaine de l'ophtalmologie afin d'imager le flux sanguin dans le pôle postérieur de l'œil. Les anomalies de perfusion jouent un rôle central dans le développement des pathologies oculaires, ce qui nécessite le développement d'instruments appropriés pour mieux le comprendre. Le LDH avait déjà démontré sa capacité à effectuer une imagerie non invasive et quantitative du flux sanguin, mais uniquement chez les rongeurs. Dans cette thèse, il est montré qu'avec une caméra rapide et une analyse à transformée de Fourier à temps court sur l'élargissement Doppler, le LDH peut imager les changements de flux sanguin dans la rétine humaine au cours du cycle cardiaque avec une résolution de quelques millisecondes. Le LDH permet de mesurer les variations systolodiastoliques propres aux artères et veines rétiniennes et peut être utilisée pour cartographier en plein champ l’indice de résistivité local permettant l’identification sans ambiguïté des artères et des veines de la rétine. Le LDH peut également être utilisé pour révéler la choroïde avec une qualité de contraste similaire à celle d'instruments de pointe basés sur l'angiographie au vert d'indocyanine et la tomographie par cohérence optique, mais contrairement à ces méthodes, le LDH fournit en outre un contraste quantitatif du flux sanguin. Cette capacité a été utilisée pour mettre en évidence de grandes différences de débit sanguin entre les artères et les veines choroïdiennes, une caractéristique qui peut être exploitée pour effectuer une autre différenciation artérioveineuse adaptée aux vaisseaux choroïdiens. Les décalages de fréquence Doppler plus élevés de la lumière diffusée dans les artères choroïdiennes permettent au LDH d'être particulièrement efficace pour les révéler, dans certains cas dès leur formation au niveau des artères ciliaires postérieures jusqu'aux ramifications artériolaires. Globalement, la résolution temporelle incomparable avec laquelle le LDH est capable de mesurer le flux sanguin et les nouveaux contrastes avec lequel il permet d'imager la choroïde en font un instrument prometteur pour la suite des applications cliniquesThis PhD aimed at introducing laser Doppler holography (LDH) into the field of ophthalmology in order to image blood flow in the eye posterior pole. Perfusion abnormalities play a central role in the development of ocular pathologies, which calls for the development of suitable instruments to elucidate it. LDH had previously demonstrated its ability to perform non-invasive and quantitative blood flow imaging with a high temporal resolution, but only in rodents. In this thesis, it is demonstrated that with a fast camera and a short-time Fourier transform analysis of the Doppler broadening, LDH can image blood flow changes in the human retina during cardiac cycles with a resolution of a few milliseconds. LDH is able to measure distinct systolodiastolic variations in retinal arteries and veins, and can be used for a full field mapping of the local resistivity index that allows unambiguous identification of retinal arteries and veins. LDH can also be used to reveal the choroid with a contrast quality similar to that of state of art instruments based on indocyanin-green angiography and optical coherence tomography, but unlike these methods LDH additionally provides a quantitative blood flow contrast. This ability was used to bring to light large differences of blood flow between choroidal arteries and veins, which is a feature that can be exploited to perform another arteriovenous differentiation appropriate for choroidal vessels. The higher Doppler frequency shifts of light scattered in choroidal arteries allows LDH to be especially efficient to reveal them, in some cases from their formation at short posterior ciliary arteries all the way to the arterioles branching. Overall, the unmatched temporal resolution with which LDH is able to measure blood flow and the new insight it provides into the choroid are especially full of promise for further clinical applications
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Brodoline, Alexey. "Holographie numérique appliquée à l’imagerie 3D rapide de la circulation sanguine chez le poisson-zèbre." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS058/document.
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Nous présentons dans ce manuscrit une technique d’imagerie basée sur l’holographie numérique. Elle permet d’imager en 3D et dans le temps la circulation sanguine chez une larve de poisson-zèbre. L’information 3D est acquise en une seule image de la caméra, ce qui permet de suivre le mouvement des globules rouges dans le système vasculaire. Nous évoquerons dans un premier temps les techniques de bio-imagerie et d’imagerie du flux sanguin traditionnelles, puis nous rappellerons les principes de l’holographie. Ensuite, nous décrirons la méthode d’imagerie que nous avons développée et les résultats expérimentaux obtenus. Nous compléterons, en présentant les différentes améliorations que nous avons apportées à la technique. Enfin, nous discuterons brièvement de l’application du compressed sensing à l’imagerie de la circulation sanguine dans le poisson-zèbreIn this manuscript, we present an imaging technique based on digital holography.It enables to image in 3D and in time the blood circulation in a zebrafish larva. The 3D information is acquired in a single frame of the camera, which makes possible to track the movement of red blood cells in the vascular system. We will first discuss the traditional techniques of bio and blood flow imaging, then we will remind the principles of holography. Afterwards, we will describe the imaging method we developed and the experimental results obtained. We will then present the improvements that have been made to the technique. Finally, we will briefly discuss the application of the compressed sensing to the blood flow imaging in zebrafish
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Schockaert, Cédric. "Three dimensional object analysis and tracking by digital holography microscopy." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210718.
Full textAbstract:
Digital Holography Microscopy (DHM) is a new 3D measurement technique that exists since Charge Coupled Devices (or CCD cameras) allow to record numerically high resolution images. That opens a new door to the theory of holography discovered in 1949 by Gabor: the door that masked the world of digital hologram processing. A hologram is a usual image but that contains the complex amplitude of the light coded into intensities recorded by the camera. The complex amplitude of the light can be seen as the combination of the energy information (squared amplitude modulus) with the information of the propagation angle of the light (phase of the amplitude) for each point of the image. When the hologram is digital, this dual information associated with a diffractive model of the light propagation permits to numerically investigate back and front planes to the recorded plane of the imaging system. We understand that 3D information can be recorded by a CCD camera and the acquisition rate of this volume information is only limited by the acquisition rate of the unique camera. For each digital hologram, the numerical investigation of front and back regions to the recorded plane is a tool to numerically refocus objects appearing unfocused in the original plane acquired by the CCD.This thesis aims to develop general and robust algorithms that are devoted to automate the analysis process in the 3D space and in time of objects present in a volume studied by a specific imaging system that permits to record holograms. Indeed, the manual processing of a huge amount of holograms is not realistic and has to be automated by software implementing precise algorithms. In this thesis, the imaging system that records holograms is a Mach-Zehnder interferometer working in transmission and studied objects are either of biological nature (crystals, vesicles, cancer cells) or latex particles. We propose and test focus criteria, based on an identical focus metric, for both amplitude and phase objects. These criteria allow the determination of the best focus plane of an object when the numerical investigation is performed. The precision of the best focus plane is lower than the depth of field of the microscope. From this refocus theory, we develop object detection algorithms that build a synthetic image where objects are bright on a dark background. This detection map of objects is the first step to a fully automatic analysis of objects present in one hologram. The combination of the detection algorithm and the focus criteria allow the precise measurement of the 3D position of the objects, and of other relevant characteristics like the object surface in its focus plane, or its convexity or whatever. These extra relevant measures are carried out with a segmentation algorithm adapted to the studied objects of this thesis (opaque objects, and transparent objects in a uniform refractive index environment). The last algorithm investigated in this research work is the data association in time of objects from hologram to hologram in order to extract 3D trajectories by using the predictive Kalman filtering theory.
These algorithms are the abstract bricks of two software: DHM Object Detection and Analysis software, and Kalman Tracking software. The first software is designed for both opaque and transparent objects. The term object is not defined by one other characteristic in this work, and as a consequence, the developed algorithms are very general and can be applied on various objects studied in transmission by DHM. The tracking software is adapted to the dynamic applications of the thesis, which are flows of objects. Performance and results are exposed in a specific chapter.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
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Dunsby, Christopher William. "Wide-field coherence-gated imaging techniques including photorefractive holography." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407465.
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Docurro, Manuel J. "Three-dimensional autostereoscopic imaging by computer based holography techniques." FIU Digital Commons, 2003. http://digitalcommons.fiu.edu/etd/3069.
Full textAbstract:
The purpose of this thesis is to explore the potential of computer based holography as a means to create autostereoscopic three-dimensional images. The methodology involved research into human three dimensional image perception and the applications of holographic techniques, both conventional and computer based, for achieving threedimensional displays. As part of the research, a physical holography laboratory setup was established, and experimental findings served to validate this approach for threedimensional image visualization. Optical holography experiments were carried out to link the theoretical premise to the practical implementations. The realized computer based approach involved a holographic stereogram technique whereby multiple two dimensional digital images are combined to form a three-dimensional holographic image. The conclusions drawn from the study include a determination of which computer based holography techniques are suited for particular applications, as well as an assessment of the current limitations and challenges experienced in the current technology.