Дисертації з теми "Optical head"
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1
Ma, Jiantao. "Optical design for a head-mounted display." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56799.
Повний текст джерелаАнотація:
This thesis reports on the design of an optical relay for use in a color, stereo Head-Mounted Display (HMD) system.Based on reviews and discussions of the requirements of the human visual system, major factors affecting the visual acuity, the aberration tolerances of the human eye, and optical design limitations, we derive the design criteria for the optical relay. A survey of alternate approaches to the three components of HMDs is presented.
A brief review of first order optics, aberration theory, general design principles, and computer aided lens design is also given.
Two multi-spherical lens systems, a straight structure and a folded layout, are presented. Their aberrations (distortion, coma, lateral color, field curvature and astigmatism) have been well corrected. Each of them has a 20 mm eye relief and an instantaneous field-of-view greater than 60$ sp circ.$
2
Partow, Sepehr 1965. "An extended cavity, self focussing laser optical head." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/291342.
Повний текст джерелаАнотація:
A feasibility study of an "Extended Cavity, Self Focussing Laser Optical Head" for optical data storage applications is presented. A general description of the proposed device is discussed followed by a prediction of its dynamic operation. This is verified by a one dimensional computer model, simulating dynamic laser head behavior. Transient laser phenomena such as longitudinal mode competition and laser frequency modulation are investigated as applicable to the device operation. The self-focussing concept is confirmed by the passive cavity experiment and a geometrical computer model of the cold cavity (i.e. no gain medium).
3
Kondreddy, Mahendra. "Image Recognition Techniques for Optical Head Mounted Displays." Master's thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-218600.
Повний текст джерелаАнотація:
The evolution of technology has led the research into new emerging wearable devices such as the Smart Glasses. This technology provides with new visualization techniques. Augmented Reality is an advanced technology that could significantly ease the execution of much complex operations. Augmented Reality is a combination of both Virtual and Actual Reality, making accessible to the user new tools to safeguard in the transfer of knowledge in several environments and for several processes.
This thesis explores the development of an android based image recognition application. The feature point detectors and descriptors are used as they can deal great with the correspondence problems. The selection of best image recognition technique on the smart glasses is chosen based on the time taken to retrieve the results and the amount of power consumed in the process. As the smart glasses are equipped with the limited resources, the selected approach should use low computation on it by making the device operations uninterruptable. The effective and efficient method for detection and recognition of the safety signs from images is selected. The ubiquitous SIFT and SURF feature detectors consume more time and are computationally complex and require very high-level hardware components for processing. The binary descriptors are taken into account as they are light weight and can support low power devices in a much effective style. A comparative analysis is being done on the working of binary descriptors like BRIEF, ORB, AKAZE, FREAK, etc., on the smart glasses based on their performance and the requirements. ORB is the most efficient among the binary descriptors and has been more effective for the smart glasses in terms of time measurements and low power consumption.
4
Branco, Gilberto. "The development and evaluation of head probes for optical imaging of the infant head." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1446225/.
Повний текст джерелаАнотація:
The objective of this thesis was to develop and evaluate optical imaging probes for mapping oxygenation and haemodynamic changes in the newborn infant brain. Two imaging approaches are being developed at University College London (UCL): optical topography (surface mapping of the cortex) and optical tomography (volume imaging). Both have the potential to provide information about the function of the normal brain and about a variety of neurophysiologies! abnormalities. Both techniques require an array of optical fibres/fibre bundles to be held in contact with the head, for periods of time from tens of seconds to an hour or more. The design of suitable probes must ensure the comfort and safety of the subject, and provide measurements minimally sensitive to external sources of light and patient motion. A series of prototype adaptable helmets were developed for optical tomography of the premature infant brain using the UCL 32-channel time-resolved system. They were required to attach 32 optical fibre bundles over the infant scalp, and were designed to accommodate infants with a variety of head shapes and sizes, aged between 24-weeks gestational age and term. Continual improvements to the helmet design were introduced following the evaluation of each prototype on infants in the hospital. Data were acquired to generate images revealing the concentration and oxygenation of blood in the brain, and the response of the brain to sensory stimulation. This part of the project also involved designing and testing new methods of acquiring calibration data using reference phantoms. The second focus of the project was the development of probes for use with the UCL frequency-multiplexed near-infrared topography system. This is being used to image functional activation in the infant cortex. A series of probes were developed and experiments were conducted to evaluate their sensitivity to patient motion and to compression of the probe. The probes have been used for a variety of functional activation studies.
5
Bushroe, Frederick Nicholas 1964. "An optical head for a magneto-optic disk test system." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277154.
Повний текст джерелаАнотація:
Design and operation of modular optical head for a magneto-optic test system are described. Alternate solutions to design problems are discussed. A 30mW semiconductor laser with an integrated 250MHz oscillator is selected. The oscillator is used to modulate laser read current for a reduction in laser feedback noise. A collimating lens with an appropriate focal length is chosen so the beam's truncation at the objective yields the maximum write power density. Astigmatism associated with the laser diode is reduced to 0.125 waves by defocusing the collimating lens and circularizing with an anamorphic prism pair. Head components are aligned within several minutes of arc by using alignment apertures and an autocollimator. Aberrations due to tilt between the disk and beam are examined and coma is found to be the major contributor.
6
Cakmakci, Ozan. "MESHFREE APPROXIMATION METHODS FOR FREE-FORM OPTICAL SURFACES WITH APPLICATIONS TO HEAD-WORN DISPLAYS." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3420.
Повний текст джерелаАнотація:
Compact and lightweight optical designs achieving acceptable image quality, field of view, eye clearance, eyebox size, operating across the visible spectrum, are the key to the success of next generation head-worn displays. The first part of this thesis reports on the design, fabrication, and analysis of off-axis magnifier designs. The first design is catadioptric and consists of two elements. The lens utilizes a diffractive optical element and the mirror has a free-form surface described with an x-y polynomial. A comparison of color correction between doublets and single layer diffractive optical elements in an eyepiece as a function of eye clearance is provided to justify the use of a diffractive optical element. The dual-element design has an 8 mm diameter eyebox, 15 mm eye clearance, 20 degree diagonal full field, and is designed to operate across the visible spectrum between 450-650 nm. 20% MTF at the Nyquist frequency with less than 3% distortion has been achieved in the dual-element head-worn display. An ideal solution for a head-worn display would be a single free-form surface mirror design. A single surface mirror does not have dispersion; therefore, color correction is not required. A single surface mirror can be made see-through by machining the appropriate surface shape on the opposite side to form a zero power shell. The second design consists of a single off-axis free-form mirror described with an x-y polynomial, which achieves a 3 mm diameter exit pupil, 15 mm eye relief, and a 24 degree diagonal full field of view. The second design achieves 10% MTF at the Nyquist frequency set by the pixel spacing of the VGA microdisplay with less than 3% distortion. Both designs have been fabricated using diamond turning techniques. Finally, this thesis addresses the question of what is the optimal surface shape for a single mirror constrained in an off-axis magnifier configuration with multiple fields? Typical optical surfaces implemented in raytrace codes today are functions mapping two dimensional vectors to real numbers. The majority of optical designs to-date have relied on conic sections and polynomials as the functions of choice. The choice of conic sections is justified since conic sections are stigmatic surfaces under certain imaging geometries. The choice of polynomials from the point of view of surface description can be challenged. A polynomial surface description may link a designer s understanding of the wavefront aberrations and the surface description. The limitations of using multivariate polynomials are described by a theorem due to Mairhuber and Curtis from approximation theory. This thesis proposes and applies radial basis functions to represent free-form optical surfaces as an alternative to multivariate polynomials. We compare the polynomial descriptions to radial basis functions using the MTF criteria. The benefits of using radial basis functions for surface description are summarized in the context of specific head-worn displays. The benefits include, for example, the performance increase measured by the MTF, or the ability to increase the field of view or pupil size. Even though Zernike polynomials are a complete and orthogonal set of basis over the unit circle and they can be orthogonalized for rectangular or hexagonal pupils using Gram-Schmidt, taking practical considerations into account, such as optimization time and the maximum number of variables available in current raytrace codes, for the specific case of the single off-axis magnifier with a 3 mm pupil, 15 mm eye relief, 24 degree diagonal full field of view, we found the Gaussian radial basis functions to yield a 20% gain in the average MTF at 17 field points compared to a Zernike (using 66 terms) and an x-y polynomial up to and including 10th order. The linear combination of radial basis function representation is not limited to circular apertures. Visualization tools such as field map plots provided by nodal aberration theory have been applied during the analysis of the off-axis systems discussed in this thesis. Full-field displays are used to establish node locations within the field of view for the dual-element head-worn display. The judicious separation of the nodes along the x-direction in the field of view results in well-behaved MTF plots. This is in contrast to an expectation of achieving better performance through restoring symmetry via collapsing the nodes to yield field-quadratic astigmatism.Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
7
Strouthidis, N. G. "Three-dimensional optical coherence tomography imaging of the optic nerve head." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1344086/.
Повний текст джерелаАнотація:
Background: the primary site of injury in glaucoma is likely to be at the lamina cribrosa (LC), deep within the optic nerve head (ONH). Optical coherence tomography (OCT) in glaucoma has, to date, focused on the detection of nerve fibre loss. Spectral domain OCT (SDOCT) has improved speed and axial resolution, allowing acquisition of three-dimensional ONH volumes and may capture targets deep within the ONH. This thesis explores the capabilities and potential of deep SDOCT imaging in the monkey ONH. Plan of research: an investigation was conducted into the detection of key landmarks that would be necessary for future quantification strategies. In particular, detection of the neural canal opening (NCO) was assessed and how the NCO relates to what is clinically identified as the disc margin. The next phase involved clarifying the anatomical and histological basis of ONH structures observed within SDCOT volumes, by comparison with histological sections and disc photographs. Finally, quantification strategies for novel parameters based on deep targets were developed and used to detect chronic longitudinal changes in experimental glaucoma and acute changes following IOP manipulation. Results: SDOCT reliably detects the NCO, which can be used as an anchoring structure for reference planes. Usually the NCO equates to the disc margin but disc margin architecture can be complex and highly variable. SDOCT captures the prelaminar tissue and anterior LC surface. Prelaminar thinning and posterior LC displacement were both detected longitudinally in experimental glaucoma. Prelaminar thinning was observed with acute IOP elevation; posterior LC movement was rare. Significance: deep ONH structures, including the LC, are realistic targets for clinical imaging. These imaging targets may be useful in the detection of glaucoma progression and in the verification of ex-vivo models of ONH biomechanical behaviour.
8
Hamadouche, I. (Ilyas). "Augmented reality X-ray vision on optical see-through head mounted displays." Master's thesis, University of Oulu, 2018. http://jultika.oulu.fi/Record/nbnfioulu-201806062540.
Повний текст джерелаАнотація:
Abstract. In this thesis, we present the development and evaluation of an augmented reality X-ray system on optical see-through head-mounted displays. Augmented reality X-ray vision allows users to see through solid surfaces such as walls and facades, by augmenting the real view with virtual images representing the hidden objects. Our system is developed based on the optical see-through mixed reality headset Microsoft Hololens. We have developed an X-ray cutout algorithm that uses the geometric data of the environment and enables seeing through surfaces. We have developed four different visualizations as well based on the algorithm. The first visualization renders simply the X-ray cutout without displaying any information about the occluding surface. The other three visualizations display features extracted from the occluder surface to help the user to get better depth perception of the virtual objects. We have used Sobel edge detection to extract the information. The three visualizations differ in the way to render the extracted features. A subjective experiment is conducted to test and evaluate the visualizations and to compare them with each other. The experiment consists of two parts; depth estimation task and a questionnaire. Both the experiment and its results are presented in the thesis.
9
Šeda, Jan. "Detekce optického disku ve snímcích optické koherentní tomografie." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220025.
Повний текст джерелаАнотація:
The main target of this work is a design of the program for border localization of the optic disc in OCT data. Part of this program is also localization of the „optic cup“ and calculation of several values that characterize optic disc. The work is also dealing with a description of the optical coherence tomography principle which is used in ophthalmology. One chapter describes some published methods of optic cup localization. Success of the program and its comparison with OCT Zeiss Stratus 3000 is evaluated at the end of the work.
10
Hu, Xinda. "Development Of The Depth-Fused Multi-Focal-Plane Display Technology." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338957.
Повний текст джерелаАнотація:
Conventional stereoscopic displays present a pair of stereoscopic images on a single and fixed image plane. In consequence, these displays lack the capability of correctly rendering focus cues (i.e. accommodation and retinal blur) and may induce the discrepancy between accommodation and convergence. A number of visual artifacts associated with incorrect focus cues in stereoscopic displays have been reported, limiting the applicability of these displays for demanding applications and daily usage. Depth-fused multi-focal-plane display was proposed to create a fixed-viewpoint volumetric display capable of rendering correct or nearly-correct focus cues in a stereoscopic display through a small number of discretely placed focal planes. It effectively addresses the negative effects of conventional stereoscopic displays on depth perception accuracy and visual fatigue. In this dissertation, the fundamental design methods and considerations of depth-fused displays were refined and extended based on previous works and a high-resolution optical see-through multi-focal-plane head-mounted display enabled by state-of-the-art freeform optics was developed. The prototype system is capable of rendering nearly-correct focus cues for a large volume of 3D space extending into a depth range from 0 to 3 diopters at flicker-free speed. By incorporating freeform optics, the prototype not only achieves high quality imagery across a large 3D volume for the virtual display path but it also maintains better than 0.5 arcminutes visual resolution of the see-through view. The optical design, implementation and experimental validation of the display are presented and discussed in detail.
11
LI, HANG. "DESIGN OF A 32 BY 32 BIT READ HEAD DEVICE FOR PAGE-ORIENTED OPTICAL MEMORY." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1037304111.
Повний текст джерела
12
Hamdoon, Z. G. "The clinical application of optical coherence tomography for head and neck premalignant/malignant lesions." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1402413/.
Повний текст джерелаАнотація:
The principle of Optical Coherence Tomography (OCT) is based on the property of light coherence. OCT generates cross-sectional images of two-dimensional objects to obtain in-vitro and in-vivo images of tissues. Non–commercially available OCT systems, which have a higher resolution and scanning rate, have been previously reported. However, some clinical research has already been conducted using the first commercially available OCT device (Niris system) to image the larynx; but applications on oral and skin tissue have not been tested yet. This thesis aims to explore, compare and validate three specific types of commercially available OCT equipment for imaging head and neck tissue. An animal cancer model has been used to verify the feasibility of one system (Niris) to differentiate normal from malignant oral tissue, using in-vivo tissue samples. Since images of oral tissue samples didn’t show much structure using the Niris system, a different machine (Michelson Diagnostic bench based) with different specifications and resolution was employed. Great emphasis has been put on validating OCT structurally and histomorphometrically in comparison to the gold standard of pathology. This was tested and validated with ex-vivo oral and skin tissues using the lab based version of the machine. Use of an upgraded system (Michelson vivo sight with probe) has been tested on abnormal oral and skin biopsy tissue but with different timing for the scan (instant ex- vivo). One original study evaluated and classified tongue papilla atrophy from patients having their suspicious tongue lesions biopsied. In conclusion, this thesis concludes that the new version of this commercially approved OCT system can be applied to the diagnosis of superficial premalignant and malignant oral and skin lesions in-vitro. Furthermore, OCT holds the promise of complementing surgery to eradicate tumors and monitor the consequences.
13
Antony, Bhavna Josephine Garvin Mona K. "Automated 3-D segmentation of intraretinal surfaces from optical coherence tomography images centered on the optic nerve head." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/330.
Повний текст джерела
14
Zhang, Rui. "DEVELOPMENT AND ASSESSMENT OF POLARIZED HEAD MOUNTED PROJECTION DISPLAYS." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195289.
Повний текст джерелаАнотація:
Head mounted projection display (HMPD) technology, as an alternative to conventional head mounted displays (HMD), offers a potential of designing wide field-of-view (FOV), low distortion optical see-through HMDs (OST-HMDs). Existing HMPD designs, however, suffer from problems of low luminance and low image resolution, which limits the applications of such information displays for the scenarios which require high luminance and high image fidelity. The design of a polarized head mounted projection display (p-HMPD) was recently proposed to overcome the challenge of low luminous efficiency in existing HMPD designs. Polarization management was employed to reduce the light loss caused by beamsplitting in an HMPD.The work in this dissertation focuses on the development and evaluation of an SXGA resolution, high efficiency p-HMPD system. The main contributions are as follows. First, the key elements in the polarization management scheme of a p-HMPD were selected and their polarization performances were characterized by measuring their Mueller matrices, based on which the overall display performance of a p-HMPD was analyzed.Second, based on a pair of ferroelectric liquid-crystal-on-silicon (FLCoS) microdisplays, a compact illumination unit and a light-weight projection system were designed, from which a p-HMPD prototype was built. Following the prototype implementation, a series of calibrations were performed to obtain correct color presentation, desired focusing setting, and optical system characteristics necessary for achieving accurate registration between virtual objects and their counterparts in the real world.Third, the imaging properties of a retroreflective screen which is an essential part of a p-HMPD or HMPD were studied and its effects on the image resolution of an HMPD system were further characterized.Finally, the performance of the system was evaluated through two objective user experiments, including a visual acuity assessment and a depth perception accuracy assessment.
15
Khaeim, Hussein M. "MASS SELECTION WITH AN OPTICAL SORTER FOR HEAD SCAB RESISTANCE IN SOFT RED WINTER WHEAT." UKnowledge, 2013. http://uknowledge.uky.edu/pss_etds/32.
Повний текст джерелаАнотація:
Fusarium head blight (FHB) or head scab, caused by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)], is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Numerous strategies for scab resistance breeding are in use, including phenotypic selection for low severity and marker-assisted selection for resistance QTL. The most destructive consequences of scab are evidenced through a reduction in grain quality, and the presence of mycotoxins, the most common of which is deoxynivalenol (DON). Thus, there is great interest among breeders in selecting for resistance to both of these traits. To this end, a study was devised as follows. In 2010, 20 bulk F3 SRW wheat populations with scab resistant parents in their pedigrees were harvested by population from unreplicated plots near Lexington, KY. The plots were affected by a naturally occurring mild-moderate scab epidemic. The grain was sorted on a USDA/ARS and National Manufacturing Seed Sorter System with color camera according to a calibration that reflected visual differences between asymptomatic grain and grain showing FHB symptoms. This process was repeated in 2011 using grain from plots that had conidial suspension applied at anthesis. In 2012, an unreplicated plot study of the C0, C1 and C2 cycles of selection, inoculated with grain spawn and conidial suspension, was evaluated for Fusarium damaged kernels (FDK) and DON concentration. An additional cycle of selection was conducted by running the bulk grain through the sorter. In October 2012, 4 selection cycles of the 20 populations were planted in a RCB experiment at Lexington and Princeton, KY. Bulk populations were planted in both scab nursery and plots, and C3 accepted and rejected of all populations and derived lines of 2 populations were planted in the scab nursery in Lexington, KY. Some populations had FDK and DON reduction with selection, and some derived lines had either numerical or significant reduction with selection. Although the accepted fraction had non-significant reduction compared with the rejected fraction over the populations, FDK and DON means were obviously lower in accepted than in rejected fractions.
16
Gibson, David. "Novel detection method of a pseudostatic CD ROM optical head using position sensitive detector arrays." Thesis, Keele University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337165.
Повний текст джерела
17
Hua, Hong. "Optical methods for enabling focus cues in head-mounted displays for virtual and augmented reality." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/626496.
Повний текст джерелаАнотація:
Developing head-mounted displays (HMD) that offer uncompromised optical pathways to both digital and physical worlds without encumbrance and discomfort confronts many grand challenges, both from technological perspectives and human factors. Among the many challenges, minimizing visual discomfort is one of the key obstacles. One of the key contributing factors to visual discomfort is the lack of the ability to render proper focus cues in HMDs to stimulate natural eye accommodation responses, which leads to the well-known accommodation-convergence cue discrepancy problem. In this paper, I will provide a summary on the various optical methods approaches toward enabling focus cues in HMDs for both virtual reality (VR) and augmented reality (AR).
18
Bauer, Mitchell D. "Characterization and Correction of Spatial Misalignment in Head-Mounted Displays." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1510943954851583.
Повний текст джерела
19
Kuhn, Jason William. "Measurement and Analysis of Wavefront Deviations and Distortions by Freeform Optical See-through Head Mounted Displays." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613396.
Повний текст джерелаАнотація:
A head-mounted-display with an optical combiner may introduce significant amount of distortion to the real world scene. The ability to accurately model the effects of both 2-dimensional and 3-dimensional distortion introduced by thick optical elements has many uses in the development of head-mounted display systems and applications. For instance, the computer rendering system must be able to accurately model this distortion and provide accurate compensation in the virtual path in order to provide a seamless overlay between the virtual and real world scenes. In this paper, we present a ray tracing method that determines the ray shifts and deviations introduced by a thick optical element giving us the ability to generate correct computation models for rendering a virtual object in 3D space with the appropriate amount of distortion. We also demonstrate how a Hartmann wavefront sensor approach can be used to evaluate the manufacturing errors in a freeform optical element to better predict wavefront distortion. A classic Hartmann mask is used as an inexpensive and easily manufacturable solution for accurate wavefront measurements. This paper further suggests two techniques; by scanning the Hartmann mask laterally to obtain dense sampling and by increasing the view screen distance to the testing aperture, for improving the slope measurement accuracy and resolution. The paper quantifies the improvements of these techniques on measuring both the high and low sloped wavefronts often seen in freeform optical-see-through head-mounted displays. By comparing the measured wavefront to theoretical wavefronts constructed with ray tracing software, we determine the sources of error within the freeform prism. We also present a testing setup capable of measuring off-axis viewing angles to replicate how the system would perform when worn by its user.
20
Wong, Kevin Winata. "HandsOn : a portable system for collaboration on virtual 3D objects using binocular optical head-mounted display." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100616.
Повний текст джерелаАнотація:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Title as it appears in the MIT Commencement Exercises program, June 5, 2015: HandsOn: a portable system AR-based remote collaboration Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 61-62).
In this increasingly globalized and technological world, professionals often have to collaborate remotely on 3D content, especially in fields such as urban planning or architectural design. We propose HandOn, a portable system for collaboration on virtual 3D objects. HandsOn leverages the recent advances in optical head-mounted display and finger tracking technology, allowing users to view digital content as if it were merged with the physical reality, while being able to manipulate the objects using simple hand gestures. Supporting both co-located and remote collaboration, this proof-of-concept system is designed to be portable and easy-to-setup, in contrast with many previous systems that require elaborate setup. Our findings suggests that HandsOn greatly increases awareness of remote collaborators and their actions by displaying the remote user'-s hands while interacting with the virtual objects, and that gestural hand-based interactions felt natural to the users. We also found that the illusion of the physical and the virtual being merged improved the overall experience, even though this aspect could be further improved by using better hardware.
by Kevin Winata Wong.
M. Eng.
21
Wissel, Tobias [Verfasser]. "Tissue thickness estimation from backscattered light : a novel concept for optical head tracking in radiotherapy / Tobias Wissel." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2017. http://d-nb.info/1125057858/34.
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22
Dong, Lixin. "DIFFUSE OPTICAL MEASUREMENTS OF HEAD AND NECK TUMOR HEMODYNAMICS FOR EARLY PREDICTION OF CHEMO-RADIATION THERAPY OUTCOMES." UKnowledge, 2015. http://uknowledge.uky.edu/cbme_etds/35.
Повний текст джерелаАнотація:
Chemo-radiation therapy is a principal modality for the treatment of head and neck cancers, and its efficacy depends on the interaction of tumor oxygen with free radicals. In this study, we adopted a novel hybrid diffuse optical instrument combining a commercial frequency-domain tissue oximeter (Imagent) and a custom-made diffuse correlation spectroscopy (DCS) flowmeter, which allowed for simultaneous measurements of tumor blood flow and blood oxygenation. Using this hybrid instrument we continually measured tumor hemodynamic responses to chemo-radiation therapy over the treatment period of 7 weeks. We also explored monitoring dynamic tumor hemodynamic changes during radiation delivery. Blood flow data analysis was improved by simultaneously extracting multiple parameters from one single autocorrelation function curve measured by DCS. Patients were classified into two groups based on clinical outcomes: a complete response (CR) group and an incomplete response (IR) group with remote metastasis and/or local recurrence within one year. Interestingly, we found human papilloma virus (HPV-16) status largely affected tumor homodynamic responses to therapy. Significant differences in tumor blood flow index (BFI) and reduced scattering coefficient (μs’) between the IR and CR groups were observed in HPV-16 negative patients at Week 3. Significant differences in oxygenated hemoglobin concentration ([HbO2]) and blood oxygen saturation (StO2) between the two groups were found in HPV-16 positive patients at Week 1 and Week 3, respectively. Receiver operating characteristic curves were constructed and results indicated high sensitivities and specificities of these hemodynamic parameters for early (within the first three weeks of the treatment) prediction of one-year treatment outcomes. Measurement of tumor hemodynamics may serve as a predictive tool allowing treatment selection based on biologic tumor characteristics. Ultimately, reduction of side effects in patients not benefiting from radiation treatment may be feasible.
23
Chang, Yu-Cheng, and 張育誠. "Optical Element of Micro-Optical Pickup Head." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/97208650079957687607.
Повний текст джерелаАнотація:
碩士國立中央大學
光電科學研究所
91
A new optical pickup head is introduced, with its optical components fabricated by the microoptoelectromechanical (MOEMS) technology. Optical elements, such as grating, holographic optical element and Fresnel lens, are made on the SiN membrane. The SiN film was deposited on the silicon wafer by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD). Its advantages include the high transmission efficiency, light weight, and easy packaging for this new proposed optical pickup head.
24
ke, Yu-Fu, and 柯育甫. "Free Space Stacked Micro Optical System and Optical Pickup head." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/85951769356612254379.
Повний текст джерела
25
Hsieh, Guan-Chung, and 謝冠群. "Novel small form factor optical head design with the holographic optical element." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/60171454203937218039.
Повний текст джерелаАнотація:
碩士中興大學
機械工程學系所
95
In this study, we demonstrate a novel small form factor optical pickup head and use the optical simulation software to design the optical system. We adopt a holographic optical element(HOE) to reduce the number of components and simplify the system configuration. Afterward, we approximate and realize the holographic optical element by the method of binary optics. In fabrication, we use lithography and etch process to accomplish it and to verify its optical efficiency for being consistent with the design values. After finishing all components of the system, we use the virtual image principle to adjust the holographic optical element for compensating the error caused by the assembly process. Finally, we carry out the practical optical head system.
26
Fu, Li-Min, and 傅麗敏. "The Near-Field Recording by Flying Optical Head." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/50607143360537392651.
Повний текст джерелаАнотація:
碩士國立交通大學
光電工程研究所
86
Most of the commercial optical storage media today use substrate - incidence recording technique which has restrictions in using high numerical aperture objective lens to achieve higher recording density. The newly contrived technique of surface - incidence recording, where the read / write beam does not have to penetrate through the substrate, can utilize objective lens of high numerical aperture for ultra - high density optical recording. The flying optical head further reduce the size of diffration - limited spot by using solid immersion lens (SIL) ,the effective NA of which can be designed to be larger than unity. Because the optical head in this method must fly near the disk surface within the range of wavelength to couple the optical energy onto the recording layer, the nearfield effect emerges. Therefore, the process of near - field recording was modeled by near - field optics because far - field theorem is no longer applicable in this case. This thesis is devoted to establish a near - field model for the flying optical head recording system. We simulate the dependence of laser power and effective spot size on various parameters of the system. Consequently, in order to achieve the effect of nearfield recording, the flying height should be less than 0.4λ and the dielectric - layer thickness be smaller than 180 nm. The storage density as high as 40 GB / side is achieved with flying height of 0.2λ, dielectric - layer thickness of 100 nm, and effective spot size of 0.15 μm.
27
Hsiung, Hsin-Chang, and 熊信昌. "Optical system design in combo pick-up head." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/28729757910924147007.
Повний текст джерелаАнотація:
碩士中原大學
應用物理研究所
92
Abstract The progression of our civilization has increased the demand for storing material day by day. People seek for those storing materials with higher storing densities. Thus, the storing media has been developed from CD and DVD to the latest HD-DVD. In order to increase the storing density, the wavelength of the pick-up head is shortened with increased NA (numerical aperture) and narrower spot size. Therefore, the aberration tolerance degree will certainly be much tighter. AS the demand for thinner and lighten storing materials grows higher, researchers must reduce the size and the weight of pick-up head. That is why optical pick-up head design becomes a crucial technology. This paper will discuss the optical system design and optimization of the lens base on the view of optical design, and mass produced DVD pick-up head, enables researchers to know the optical system structures and design process. Then we combine CD with DVD pick-up head to form so-called ‘‘combo pick-up head’’. This thesis regardes Blue Ray HD-DVD as the systematic specification. Base on DVD system, the researcher redesign HD-DVD pick-up head. To reduce the size of the pick-up head, this study uses the special character that light travels longer distance in prism than in air and proposes four kinds of different optical system. This paper hopes to know batter bout next generation optical pick-up head and to help future researchers in the field of optical design.
28
Wang, Chih-Ming, and 王智明. "Micro and Nano Optoelectronics in Optical Head Applications." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/g4rnh3.
Повний текст джерелаАнотація:
博士國立中央大學
光電科學研究所
94
This thesis investigates the optics of micro and nano scaled structures, called microoptics and nanooptics. Microoptics and nanooptics continue to advance and diversify due to rising demands for miniaturization, cost reduction, functional integration, and increased performance in optical and photonic systems. Micro- and nano-optics are playing increasing roles in a wide range of applications, including sensors, communications, biomedical, data storage, and other consumer-driven and technology-driven areas. This thesis focuses on the microoptical and nanooptical devices which can be used in optical pickup head system. The main content of this thesis can be separated into two parts: A part of this dissertation presents the realization of a miniaturizing optical head using microoptical and micromachining techniques. Another part of this dissertation presents the near-field properties of a nano aperture which has high potential for optical storage applications. By using the microoptical technology, we have developed a novel stacked silicon-based microoptical system, which is optical-on-axis and transmissible in both visible and infrared ranges. By using this new microoptical system technique, we fabricated a miniaturized optical pickup head module. This optical pickup head consisted of a 650-nm laser diode, a 45o silicon reflector, a grating, a holographic optical element, and some aspherical Fresnel lenses. These optical phase elements fabricated on a SiNx membrane were suspended on Si chips. Each element was then stacked by chip bonding. The integrated optical head had an area of 10x10x5 mm3. The total weight was about 1.25g. The optical performance was successfully characterized. The tracking servo signal pattern on optical disc was measured and a focal spot with an FWHM diameter of 3.1�慆 was obtained, while the diffraction-limited spot size was 0.7�慆. The optical phase elements are made on free-standing SiNx membranes which provide versatile optical functions, such as focusing, splitting, and so on. Since the fabrication process is based on silicon micromachining technology, the optical element is easily integrated with other active and passive devices on a silicon substrate. As mentioned, the other part of this dissertation presents the near-field properties of a nano aperture. The spatial resolution of a small aperture is not limited by diffraction but generally determined by the aperture size, beyond the diffraction limit can be achieved using a nano aperture. Unfortunately, a conventional small aperture has a devastating problem of extremely low transmission. For a small circular aperture, calculations and experiments show that power throughput decays as the fourth power of the aperture size. This low transmission problem greatly hinders the application of a nano aperture for solving significant problems. It has been shown that a large transmission enhancement can be obtained when a nano-scaled slit is surrounded by periodic trenches on the entrance plane of a metallic film. However, until now, the transmission through the nanostructure-surrounded nano-scaled slit is still too low for practical applications. In this thesis, two new methods for further transmission enhancement are proposed: 1. Metallic bumps are used for recycling the surface waves; 2. Tapered substrate is used for propagating constant matching and efficiently exciting surface waves. In this thesis, a very large transmission, 20%, of light through a nano metallic slit bordered by both nano trenches and bumps has been demonstrated theoretically. To the best of our knowledge, this is the first time that a bump structure is proposed for transmission enhancement. The trenches bordering the nano slit are used to excite free-space light into surface waves, while the bumps bordering the trenches are used to confine surface wave leakage. Over 50% of the escaping surface waves can be reclaimed by using a pair of bumps with a reflectivity larger than 99%. As a result, the transmission of a trench-surrounded slit bordered by a pair of bumps can be enhanced 1.5 fold. Furthermore, a nano slit on a tapered metallic substrate was also investigated. By using a 45o tapered structure rather than a traditional metallic plate, a 6-fold transmission enhancement could be achieved, due to the asymmetrical excitation of surface waves and the matching of propagation constants between the surface waves and slit waveguide.
29
Chang, Po-Kuang, and 張伯光. "Optical design of head up display for helmet." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/20957266331726657443.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
光電科技研究所
101
This research focuses on designing an optical system of head-up display (HUD).We use an eyepiece system to design the optical system. When head-up display provide us image information, we can see an enlarged virtual image which is in front of our eyes at a certain distance. It has see-through effects. In other words, we can see the display of information and information from the background at the same time. We also use lens to eliminate optical aberrations and we can get the image quality which is better. Finally, we set up the optical system to verify optical system. And we check HUD system for commercial applications.
30
Huang, Dai-Tin, and 黃戴廷. "Design of a Novel Optical Pickup Head Actuator." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/04437687537038474090.
Повний текст джерелаАнотація:
碩士國立清華大學
動力機械工程學系
87
This research presents a novel design of the optical pickup head actuator for improving the performance deficiencies due to its heavy mass and large volume. Different from the pickup head of current optical disc drives, the coils and magnets are arranged along the axial direction for the purpose of space saving. The proposed prototype possesses the advantages, such as lighter, smaller, thinner, and less components. Furthermore, by integrating micro-electromechanical processes with electric circuits to produce much smaller actuators can meet the future trend of the optical storage technology because of their quasi-plane arrangement. This paper summarizes relative literatures and introduces working principles for the required performance of optical pickup head actuators. From conceptual design to prototype implementation, magnetic theories, such as equivalent magnetic circuit method, equivalent magnetic charge method, and equivalent current method are used to analyze the characteristics of the actuator. Finite element analysis software, ANSYS, is also applied to predict structural vibration. Finally, the dynamic characteristics of the actuator are tested by using a laser doppler vibrometer. In comparison with an existing optical pickup head, SPU3200, manufactured by Sankyo Seiki Mfg. Co., about one-third moving mass of the actuator is reduced. In addition, six and half times higher in stiffness, three and half times higher in open-loop bandwidth are achieved.
31
Chen, B. H., and 陳炳宏. "Vibration of Actuator of Optical Pick-up Head." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/70239444347365024978.
Повний текст джерелаАнотація:
碩士國立成功大學
機械工程學系
87
An optical pickup actuator is an objective lens movingmechanism that provides a means to accurately follow the disk (DVD) and high-speed CD-ROM drive have become popular. Since drive speed and physical density of the optical disc have become higher, better performance and higher precision are required of the actuator. Moreover, since it is used in very thin design for portable personal computers, small and thin become desirable. In addition, a CD/DVD-compatible pickup may require different actuator design.
32
Tsai, Hung-Chang, and 蔡宏昌. "Single sensor of combo optical pick-up head." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/2v835y.
Повний текст джерелаАнотація:
碩士國立中央大學
光電科學研究所碩士在職專班
97
The traditional design of a combination of Blu-ray and DVD was needed to use a number of objective lens, photo-electricity sensors and optical axes for a combo optical pick-up head, the disadvantage of this design is that higher cost occurred, a complicated construction, a time-consuming process and optical axis checking, and the entire optical path is large. This research proposes a design of a combo-optical pick-up head with a single photo-electricity sensor, its uses prisms and coatings to divide the light on the forward path, and uses the holographic optical element (HOE) on the returning path. For this design, it presents that we can use an objective lens, a collimating lens and a wavelength selector for two different wavelength light sources of Blur-ray and DVD. Because it uses less elements of an optical pick-up head, it can help cost down, processes simplified, and easy to produce. With such a design, the whole optical path will be shorter than traditional ones, it will be significant help for a miniaturized combo-optical pick-up head in the future.
33
Hsieh, Min-sheng, and 謝敏生. "Highly Efficient Optical Pickup Head for Blu-ray Disc." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/50724321566424895509.
Повний текст джерелаАнотація:
碩士國立中央大學
光電科學研究所碩士在職專班
95
The low efficiency of traditional pickup head is limited by the difference of vertical divergent angle and horizontal divergent angle. The vertical divergent angle is much larger than the horizontal one. To get the circular laser beam, the collimating lens is designed with the divergent angle which intensity is in the horizontal direction. Therefore there is a lot of energy wasted. This thesis uses the cylindrical afocal system and the prismatic system to expand the beam separately in the horizontal direction. The expander makes the beam size which intensity is in the horizontal direction as large as the beam size which intensity is in the vertical direction. Then the highly efficient collimating lens is designed with the divergent angle in the vertical direction. First, this thesis designs traditional Blu-ray Disc pickup head. It covers the design of its objective lens, the design of its collimating lens, tolerance analysis and the focusing error signal, and then simulates the total efficiency. This thesis introduces the concept of beam expanded in the horizontal direction to improve the total efficiency. This thesis designs the cylindrical expander and prismatic expander. It also covers the design of the collimating lens, tolerance analysis and the focusing error signal, and then simulates the total efficiency. At last summarize all of the new designs which are proposed by the thesis.
34
Li, Yu-Lin, and 李育霖. "Nanometer Aperture Probe Array of Optical Pickup Head Design." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46643151217492383399.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
電機工程學系
97
In the optical storage technology, in order to get the higher density of storage, we must be narrow recording spot size for overcome diffraction limit. So savants propose near field theory to improve it. In near field theory, nanometer aperture probe and solid immersion lens (SIL) can overcome diffraction limit and narrow recording spot size. But power of light through nanometer aperture probe is very low. If we combine nanometer aperture and solid immersion lens, the power will increase. But the nanometer aperture probe and solid immersion lens size are different too much, the alignment is difficult, so we propose use cylindrical solid immersion lens scanning on the nanometer aperture probe, this method can improve misalignment. If we calculate total internal reflection of solid immersion lens produce evanescent wave distance, and design length of nanometer aperture probe, we can get better power for nanometer aperture probe so we optimize size and length of nanometer aperture probe. And then we add micro lens and micro cylindrical lens on the nanometer aperture probe, the power will increase.Our using type neural network analyzes the deviation angle of light source, with the lens structure of revision.
35
Wang, Yeong-Feng, and 王湧鋒. "Study of Nanoimprint Fabrication Method for Nanowriter Optical Head." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/20538128824793856662.
Повний текст джерелаАнотація:
碩士國立臺灣大學
應用力學研究所
92
The objective of this thesis is on the fabrication of optical heads for nanowriters using nanoimprint lithography. Nanowriters focus light by sub-wavelength periodic structures, in which extraordinary optical transmission and directional beaming phenomena occur. The phenomena exhibit high energy transmission and small divergence angle so that nanometer light beams can be induced without using optical lens. Consequently nanowriters can provide better exposure resolution than conventional laser writers. Because the cost for optical heads is high with conventional fabrication methods, nanoimprint lithography, a high-throughput, low-cost method, is chosen to make nanowriter optical heads. Let is hoped that such a fabrication process can provider an economical alternative for mass production of optical head. The quality of a mold greatly affects the results of nanoimprint lithography. This work uses e-beam writer to define nano-patterns and then manipulates ICP to transfer structures to 3-inch silicon wafers. Finally hot embossing machine is utilized to imprint nano-pattern arrays on 3-inch wafer. The related details are discussed in this work. The discussions include: some conception of e-beam lithography patterning design and parameters of exposure and develop, the problems during ICP etching, adjusting imprint status by material properties and hot embossing equipment.
36
Yu, Yi-Chun, and 余逸群. "Two-Wavelength Microscopic Interferometry Using the Optical Pickup Head." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/28373294397033769983.
Повний текст джерелаАнотація:
碩士國立中興大學
機械工程學系所
94
The study is based on the structure of the two-wavelength DVD optical pickup head to accomplish the technology of two-wavelength microscopic interferometry. We modified the optical system of a commercial DVD optical pickup head as our measuring apparatus. By using the phase-shifting technique, we can improve the limitation of measurement on the vertical depth for the single-wavelength phase-shifting interferometry. A two-wavelength microscopic interferometer with lower cost and compact size can be achieved. There were two types of microscopic interferometry, Linnik and Mirau, adopted in our experiments, respectively. Optical elements in the pickup head were used as the light sources and beam-splitting elements for the proposed two-wavelength microscopic system. The key idea was to use the two laser wavelengths in a DVD pickup head for calculating an equivalent wavelength using the theory of two-wavelength interferometry. It could extend the depth limitation between adjacent pixels which was originally confined to be less than a quarter wavelength. In the real operation, the measuring surface was shifted by using the computer to control the piezoelectric transducer (PZT) for obtaining the interference image. This image then returned to the charge couple device (CCD) along the original path of the pickup head. We calculated the captured image by the five-step phase-shifting technique to get the wrapped phase. Finally, the surface profile and height were unwrapped by applying the reliability analysis method. The experimental results show that a two-wavelength microscopic interferometer, which is based on a two-wavelength DVD optical pickup head, can not only improve the measuring limitation on the vertical depth for the single-wavelength phase-shifting interferometry but also reduce the size of the system. Besides, the purpose of lower cost and simple structure can be possibly achieved for the two-wavelength microscopic interferometer.
37
溫亦謙. "Gray Scale Mask Produced by Optical Pick-up Head." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/86124091007715272730.
Повний текст джерелаАнотація:
碩士國立交通大學
電機與控制工程系所
95
There are many different gray scale mask fabrication processes in gray scale mask, such as half tone mask, high energy beam sensitive (HEBS) glass gray scale mask, and laser direct write (LDW) glass gray scale mask. They are attractive recently due to the simple photolithography process. Because the price of the HEBS glass and LDW glass is too expensive, the professional film is used to produce the gray levels by a DVD optical pick-up head. The DVD optical pick-up head in this thesis is composed of the tracking actuator, the focusing actuator, the objective lens, the photo detector, the laser diode, and so on. The focusing actuator can drive the objective lens in the vertical direction. When the distance is not in focus, the focusing error signal is produced by the photo detector and the PI controller compensates the error. Then, the distance is focused. The tracking actuator driven by the driving circuit actuates the objective lens in the horizontal direction. Because there is no data track in the film, there is no tracking error. Therefore, the movement of the objective just can be controlled by the driving circuit, and the smallest movement is 4.68 μm. The laser diode driven by the driving circuit can emit the different intensity of the laser. Because the numerical aperture of the objective lens is 0.67, the smallest spot size in the film is 0.617 μm. The tracking actuator moves the objective lens to a specific position, and the specific emitting time and power of the laser is emitted by the laser diode. Then, the laser passes through the objective lens, and the spot is focused on the film. The above steps are repeated, and the different value of exposure is received in every position of the film. Gray scale levels are produced in the exposed film through the processing. The target of the thesis is to produce the gray scale film mask within a 500μm range. the gray scale view can be analyzed by the optical microscope and Matlab.
38
Chiang, Po-Jung, and 江柏融. "Micro Optical Pickup Head Design and Analysis Based on Single Mode Optical Fiber System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18772864599450405777.
Повний текст джерелаАнотація:
碩士國立交通大學
機械工程系所
97
Blu-ray Disc drive systems become the mainstream on optical data storage products market because of its high storage capacity. However, the BD optical pickup head is quite bulky because it has to be backward compatible with CD and DVD discs caused the BD optical pickup system needs to equip different laser light sources. So, the important subject for research and development of BD pickup head is how to reduce the size and weight. This article introduces the system structure of micro optical pickup head design and analysis based on single mode optical fiber system to separate the laser diode optics modules and driving circuit board from optical pickup head for reducing the size and weight of traditional optical pickup head. Keywords: Single mode fiber, objective lens, optical fiber pickup head.
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Cheng, Hao-Der, and 鄭浩德. "Integrated Tracking and Focusing Micro-Optical-System for the Application of Optical Pickup Head." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/02184200268768190520.
Повний текст джерела
40
周學良. "Development of optical head combined with micro aperture, solid immersion lens, and optical fiber socket." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/45372131253343535161.
Повний текст джерелаАнотація:
碩士國立交通大學
機械工程系
90
The research describes the fabrication processes of an integrated optical pick-up head for near field recording that combines a tiny aperture, a smooth microlens, and a insertion socket for optical fiber. Conventionally, micro apertures and microlenses in optical pick-up head are fabricated separately, and then are assembled together. Here a fabrication process without bonding to combine all the desired components on a single substrate is proposed. The cone-shape aperture is fabricated by reflow and an improved electroplating method. Then a thermal reflow process is used to form the smooth microlens made of AZP 4620 with the refractive index from 1.63 to 1.82. The diameter ranges from 50 μm to 110μm. After that, SU-8 support is fabricated to act as the insertion socket of the optical fiber and to enforce the device strength.
41
Lin, Chun-Cheng. "Study of SOI Devices Applied to Optical Pickup Head Systems." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0021-2004200710364777.
Повний текст джерела
42
Yen, Chih-Wei, and 顏志偉. "Fabrication Process of Hologrphic Optical Elements for Head Mounted Display." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/11294425969188396881.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
光電科技研究所
100
In this study, our propose is to fabrication process of holographic optical elements for head mounted display. We provide PDLC and PQ/PMMA to be the HOEs for HMDs which we design. For PDLC, We stirred these five materials in our proportion to be PDLCs whose cell gap are 20 μm(3cm*3cm*20μm),and seal it up. It’s PDLC we need. For PQ/PMMA, We stirred these three materials in our proportion to be PD/PMMAs whose cell gap are 2 mm (7cm*7cm*20μm). We use the silicone to seal it up. The viscous solution was finally poured into a glass cell and baked at 40℃ for 3 days. The yellowish bulk photopolymer with 2 mm thickness was obtained. We use two materials to prove whose can be HOEs for HMD application. PQ/PMMA needs high power to reconstruction. We design two kind of HMD. The design principle of these systems is that the Holographic Optical Element will diffract a virtual image locating at infinity for the observer’s eye. These solutions show the original image and the projection virtual images observed via the reflection-type HOE. Due to the diffraction efficiency and angle of view are not good enough, so our pictures after reconstructing are some fuzzy in the corner. Both these still provide enough information to recognize. It proves that we provide two materials to be HOEs for HMDs.
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Chang, Ming-Wen, and 林建憲. "Spot Check and Image Analysis for the Optical Pickup Head." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/77249075041573002005.
Повний текст джерелаАнотація:
碩士元智大學
電機工程研究所
89
Abstract The first part focuses on the Optical Pickup Beam Pattern Evaluation System. It describes that the characteristics of the Optional Pickup Head, the optional magnifying properties’ analyses, and what the digital signal deals with. The second part is the focal point of my study. From the beginning Optical Lens Designs, first I analyzed the reasons of the aberration of the Spot Size and the properties of the laser illuminant. And then I took a traditional microscope as an example to rebuild its optical path. Process of the changing into evaluation system for DVD Pickup System, I found that besides the ideal optical terms, the stability of this system and the accuracy of the move on the plate are also the important mechanical factors. In the image process of access，the main idea is that how to prevent the image from lose and making the whole Evaluation System Real-Work, have high accuracy and repetition. And then we used the Zemax simulating different tilts of the optical system to compare the differences of the coma. Hope that we can get a better performance on the adjustment .The last one is the whole Optional System’s testing and the final results; we can get to the best situation by the simplest way. Besides, we also can demonstrate that the design can work normally and the accuracy can fit the needs.
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Falcão, João Pedro Silva. "Surgical Navigation using an Optical See-Through Head Mounted Display." Master's thesis, 2019. http://hdl.handle.net/10316/88100.
Повний текст джерелаАнотація:
Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e TecnologiaSurgical navigation consists in guiding the surgeon during medical procedures, having important benefits such as the improvement of the clinical outcome and the decrease in the surgeon's learning curve. Recently, Perceive3D developed in.nav, which is a system for intra-operative navigation based in video that makes use of augmented reality to safely guide the medical procedures. By using only a monocular camera and small fiducial markers, in.nav overcomes the two main drawbacks inherent to the common Optical Tracking systems: the required high capital investment and the difficulty in preserving lines-of-sight in the Operating Room.The in.nav system currently runs in standard PCs and tablets. This thesis focuses on implementing in.nav in an Head Mounted Display (HMD). This brings important advantages that include the improvement of the visibility of the screen by the surgeon, enabling him/her not to move sight from anatomy, and the fact that it removes the need for an extra pair of hands for holding the screen.This implementation consists in the development of an application to serve as interface between in.nav and the HMD, through which all the necessary information is transmitted. This interface presents two different modes: one where the HMD serves to virtualize a conventional 2D display and another where the rendering of guidance information is done directly over the patient's anatomy. In order to provide a pleasant and useful user experience, the latter approach requires an accurate calibration of the HMD. This is accomplished in the last part of this thesis, as demonstrated by the thorough experimental validation.Although the technology of HMDs still presents some problems, such as the vergence-accommodation conflict, the work developed in this thesis yielded a simple, accurate and easy to use AR headset for surgical navigation.
Navegação Cirúrgica consiste em guiar o cirurgião durante procedimentos médicos, tendo vários benefícios desde a melhoria de resultados clínicos até à redução do tempo da aprendizagem do cirurgião. Recentemente, a Perceive3D desenvolveu o in.nav que consiste num sistema de navegação cirúrgica baseado em vídeo, com utilização de realidade aumentada para guiar procedimentos médicos. Com a utilização de uma camara monocular e de vários pequenos marcadores, o in.nav supera as duas principais desvantagens inerentes aos sistemas de Optical Tracking: o elevado investimento de capital necessário e a dificuldade de preservar lines-of-sight na sala de operações.O sistema in.nav atualmente funciona em computadores e tablets. Esta tese tem como foco a implementação deste sistema em óculos de realidade aumentada. Com esta implementação, várias vantagens pode ser retiradas que incluem o melhoramento da visibilidade do ecrã pelo cirurgião, permitindo que não seja necessário desviar o foco da anatomia e o facto de já não ser necessário uma pessoa auxiliar para segurar o tablet ou computador. Este trabalho consiste no desenvolvimento de uma aplicação que serve de interface entre o in.nav e os óculos, pela qual toda a informação necessária é transmitida.-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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Chen, Ching-Chung, and 陳慶忠. "Optical design for a compact see-through head-mounted display." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/swsbk8.
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46
Lau, David Pang Cheng. "Raman spectroscopy for optical diagnosis in head and neck tissue." Thesis, 2006. http://hdl.handle.net/2429/18336.
Повний текст джерелаАнотація:
Background and Aims: Raman spectroscopy (RS) uses light to detect vibrational characteristics of molecules and can distinguish different molecular structures. Extrapolating this to a medical setting, it was hypothesized that RS could be used to make a tissue diagnosis if it could detect molecular changes associated with tissue pathology. The main aims of this study were to determine whether: 1. Raman spectra could be obtained rapidly in-vitro from head and neck tissue, and 2. Differences could be detected between benign and malignant tissue in various sites in the head and neck. Methodology: A Raman spectrometer with 785nm excitation laser and a charge-coupled device detector was used to acquire spectra in-vitro from nasopharyngeal, laryngeal and thyroid tissue. Spectral acquisition times ranging from 1 to 30 seconds were studied. Spectra from benign and malignant tissue in the different sites were compared using statistical techniques, with histopathology as the "gold-standard" for diagnosis. Results: Good quality spectra were acquired within 5 seconds. Paired analysis of nasopharyngeal specimens (n=6) showed significant differences between benign and malignant tissue at 1297-1305, 1377-1381, 1436-1442, 1541-1555, and 1614-1626cm⁻¹. Paired thyroid tissue analysis (n=5) showed differences at 1264-1266 and 1477cm⁻¹. Unpaired analysis using multivariate statistical techniques showed sensitivity and specificity values in differentiating benign and malignant tissue of 83.3% and 72.7% for nasopharynx (n=23), 69.2% and 94.1% for larynx (n=47), and 86.7% and 70.0% for thyroid (n=65). In addition in the larynx, squamous papilloma could be distinguished from normal tissue and carcinoma with sensitivity and specificity of 87.5% and 93.5% respectively. Conclusions: The system could acquire spectra rapidly in-vitro and has potential for in-vivo application in the head and neck, although specialized probes will need to be developed for this purpose. Spectral differences were detected between benign and malignant tissue in the nasopharynx, larynx and thyroid. Although diagnostic sensitivity and specificity are currently lower than histopathology, they are sufficiently high to warrant further study of this technique as a means of achieving non-invasive tissue diagnosis. Other areas requiring further development include evaluation of wider spectral ranges and characterization of spectra at cellular and biochemical levels.Surgery, Department of
Medicine, Faculty of
Graduate
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Zheng-YunLiu and 劉政運. "System Identification and Vibration Disturbance Control of Optical Pickup Head." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39497456248834496957.
Повний текст джерелаАнотація:
碩士國立成功大學
機械工程學系
103
In this thesis, the primary objective is to establish a dynamic model of the suspension system of optical pickup head which is built-in the CD-ROM, and to use shaker as input vibration source and laser displacement sensor for the identification of parameters of suspension system model. Since that suspension system use polymer as damping device, it has nonlinear and time-varying properties such as hysteresis, precondition, creep deformation and relaxation. By utilizing creeping experiment, traditional rheological and fractional differential damping models are compared and justified. The parameters of spring constant and mass are obtained through static equilibrium test. In establishing dynamic suspension model, a fractional derivative is employed to model the damping of polymer material and the input sinusoidal vibration to system responses by using approximate analytical solution, numerical solution and experimental test are obtained to compare and validate system model. In addition, simulate an environment with disturbance by shaker, and use the model of system which has been identified combine with feedforward control to finish disturbance response control.
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Lin, Chun-Cheng, and 林俊誠. "Study of SOI Devices Applied to Optical Pickup Head Systems." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/57737602021283767238.
Повний текст джерелаАнотація:
碩士國立臺灣師範大學
光電科技研究所
93
In this thesis, we design optical pickup head system by MMI-based PBG waveguide optical splitter with a square-lattice photonic crystal and Mach-Zehnder structure with a hexagonal-lattice photonic crystal building on SOI wafer. MMI-based PBG waveguide optical splitter with a square-lattice photonic crystal is based on self-image phenomenon. We design the device according to the self-image phenomenon in MMI optical splitter based on SOI rib waveguide. We use the technique of photonic bandgap and line defect to control the direction of the light wave propagation in a waveguide. Besides, Mach-Zehnder structure with a hexagonal-lattice photonic crystal is also used to design as an interferometer.
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Lee, Chia-Wen, and 李家雯. "A Micro-focusing Stage Applied to Optical Pick-up Head." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/54410862058553308093.
Повний текст джерелаАнотація:
碩士國立清華大學
動力機械工程學系
91
As the progress of IT, the need for high speed and high density data storage has become increasingly important. Denser and faster data storage is needed for optical data storage system. However, commercial optical disk pick-up head assembles optical components complex and precisely. The cost and the precision become the issue. By the way, the potential of developing portable optical data storage is high. So, the MEMS technology with batch and self-align property become a way to make faster and more tiny pick-up head. This study proposes a novel design of micro-focusing stage for optical pick-up head application. The stage witch fabricated by MUMPs-like process and backside etching process is make up of several stress-induced beams and a micro-lens plate. The stress-induced beams not only use for self-assembly but actuating stage. By controlling these stress-induced beams, the stage have piston motion to adjusting focal length and tilt motion to compensating the deviation of disk. Making the laser spot always on disk and laser beam always been orthogonal with disk.
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Huang, Po-Chian, and 黃柏蒨. "Design of two-stage optical pick-up head focus servo." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/44429843804519237703.
Повний текст джерелаАнотація:
碩士國立交通大學
機械工程系
87
In this thesis, we design a two-stage focus servo system for the optical pick-up head. According to the native restriction of the focus mechanism, there is a nonlinear effect in the system. We first analyze the system with linear assumption first. Based on the stability criterion, we have specifications for steady state error, and focusing requirements designed the compensators. Taking the simulation tests for a step response and a signal of mixed frequency using the compensator we have examined. The step response is sound, both rising time and overshoot is improved to 0.00005 sec and 1.17%. Although both coarse stage and fine stage yield good response in low and high frequency signals. But the fine stage has difficulty for completing the movement due to the limitation of stroke for the mixed frequency signals expressing the effect of disk warp and axial runout. After a redesign step the compensator that increases the bandwidth of coarse stage yields a better result. The simulation resultant shows the error reduce under 0.23 . In addition, we use MT1105F servo chip to offer a method to implement the controller due to the firmware.