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Dissertations / Theses on the topic 'Profilometry'
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1
Fojtík, Tomáš. "Systém pro precizní 3D snímání spojitého povrchu nožní klenby." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220692.
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This thesis deals with the development of the user interface for the application of the method Phase shifting profilometry. First deals with the theoretical approach of this method, and describes the process of image segmentation and data processing using morphological operations. In the practical part of the user interface is designed for acquiring and processing data received in Matlab.
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Aumond, Bernardo Dantas 1972. "High precision profilometry." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46102.
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Clark, Stephan Richard. "Optical reference profilometry." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289168.
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The Optical Reference Profilometer is a new coordinate measurement machine (CMM) configuration that utilizes a special optical referencing frame to provide a highly stable and highly accurate surface measurement. This new referencing frame provides several mechanical advantages that make it possible to use lower precision mechanical components while still maintaining a high measurement accuracy. The Optical Reference Profilometer also provides a reduced measurement sensitivity to thermal variations of the system. With the addition a Super-Invar metering rod network, this CMM system is essentially thermally insensitive to temperature changes on the order of 1°C. This special feature makes the Optical Reference Profilometer functional at a high measurement accuracy level in an open lab environment. For the current dissertation work, two profilometer designs were built: a prototype and a second-generation system. A discussion of both systems will be given where the advantages of the optical reference frame design will be shown, This dissertation will end with a discussion of the overall system performance and plans for future work that would increase the overall system accuracy. The optical reference profilometer has proven to be a viable testing device. It provides a high accuracy surface measurement, 100nm peak-to-valley and 15nm rms for surface slopes up to 20 degrees, with simple mechanical structures while maintaining the versatility to measure a variety of surface shapes.
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Yang, Ho Soon. "Developments in stylus profilometry." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342210.
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Aumond, Bernardo Dantas 1972. "High precision stereo profilometry." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/88892.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (leaves 186-190).
Metrological data from sample surfaces can be obtained by using a variety of profilome try methods. Atomic Force Microscopy (AFM), which relies on contact inter-atomic forces to extract topographical images of a sample, is one such method that can be used on a wide range of surface types, with possible nanometer resolution (both vertical andlateral). However, AFM images are commonly distorted by convolution, which reduces metrological accuracy. This type of distortion is more significant when the sample surface containshigh aspect ratio features such as lines, steps or sharp edges or when probe and sample share similar characteristic dimensions. Therefore, as the size of engineered features arepushed into the micrometer and sub-micrometer range by the development of new high precision fabrication techniques, convolution distortions embedded in the images becomeincreasingly more significant. Aiming at mitigating these distortions and recovering metrology sound ness, we introduce a novel image deconvolution scheme based on the principle of stereo imaging. Multiple images of a sample, taken at different angles, allow for separation ofcon volution artifacts from true topographic data. As a result, accurate samplereconstruction and probe shape estimation can be achieved simultaneously. Additionally, shadow zones, which are areas of the sample that cannot be reached by the AFM probe, are greatly re duced. Most importantly, this technique does not require a priori probe characterizationor any sort of shape assumption. It also reduces the need for slender or sharper probes,which, on one hand, induce less convolution distortion but, on the other hand, are more prone to wear and damage, thus decreasing the overall inspection system reliability.
(cont.) This research project includes a survey of current high precision metrology tools and an in-depthanalysis of the state of the art deconvolution techniques for probe based metrology instruments. Next, the stereo imaging algorithm is introduced, simulation results presented and anerror analysis is conducted. Finally, experimental validations of the technique are carried outfor an industrial inspection application where the characteristic dimensions of the samplesare in the nanometer range. The technique was found to be robust and insensitive to probe or shape geometries. Furthermore, the same framework was deemed to be applicable to other probe based imaging techniques such as mechanical stylus profilometers and scanning tunneling microscopy.
by Bernardo Dantas Aumond.
Ph.D.
6
Chiu, Cheng-Jung. "Data processing in nanoscale profilometry." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36677.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.Includes bibliographical references (p. 176-177).
New developments on the nanoscale are taking place rapidly in many fields. Instrumentation used to measure and understand the geometry and property of the small scale structure is therefore essential. One of the most promising devices to head the measurement science into the nanoscale is the scanning probe microscope. A prototype of a nanoscale profilometer based on the scanning probe microscope has been built in the Laboratory for Manufacturing and Productivity at MIT. A sample is placed on a precision flip stage and different sides of the sample are scanned under the SPM to acquire its separate surface topography. To reconstruct the original three dimensional profile, many techniques like digital filtering, edge identification, and image matching are investigated and implemented in the computer programs to post process the data, and with greater emphasis placed on the nanoscale application. The important programming issues are addressed, too. Finally, this system's error sources are discussed and analyzed.
by Cheng-Jung Chiu.
M.S.
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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.
8
BELL, BERNARD WHITE JR. "DIGITAL HETERODYNE TOPOGRAPHY (MOIRE, CONTOURING, PROFILOMETRY)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187971.
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Digital heterodyne methods are employed in conjunction with periodic fringe projection to produce a fast automated surface relief measurement technique. A method of sampling the image with a solid state detector array which produces a moire fringe image free of the noise terms normally present with moire techniques is presented along with an extension to Whittaker-Shannon sampling theory to cover the moire aliasing phenomena. The limitations imposed on the surface slopes by the requirement that the properly moire sampled image spectra must be confined to a moire interval are given. Moire sampling allows an optical processing step (removal of the reference surface tilt), while classical nonaliased sampling produces the same information with respect to a tilted surface. General additive noise is analyzed as regards both integrating bucket and phase stepping algorithms and yields a signal to noise ratio dependent error with twice the frequency of the fringes for some algorithms. A phase averaging technique which eliminates these oscillatory errors as well as those caused by reference phase shift errors in all the algorithms is demonstrated. Both parallel and divergent geometries are discussed. The feasibility is experimentally demonstrated with results for the parallel case based on a system composed of commercially obtainable components.
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Johnson, Max LeGrand Jr. "Characterization of geotechnical surfaces via stylus profilometry." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20705.
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Coggrave, Charles Russell. "Temporal phase unwrapping : development and application of real-time systems for surface profile and surface displacement measurement." Thesis, Loughborough University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251061.
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Pennington, Timothy L. "Miniaturized 3--D Mapping System Using a Fiber Optic Coupler as a Young's Double Pinhole Interferometer." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27993.
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Three--dimensional mapping has many applications including robot navigation, medical diagnosis and industrial inspection. However, many applications remain unfilled due to the large size and complex nature of typical 3--D mapping systems. The use of fiber optics allows the miniaturization and simplification of many optical systems.
This research used a fiber optic coupler to project a fringe pattern onto an object to be profiled. The two outputs fibers of the coupler were brought close together to form the pinholes of a Young's Double Pinhole Interferometer. This provides the advantages of this simple interferometer without the disadvantage of power loss by the customary method of spatially filtering a collimated laser beam with a pair of pinholes. The shape of the object is determined by analyzing the fringe pattern. The system developed has a resolution of 0.1mm and a measurement error less than 1.5\% of the object's depth.
The use of fiber optics provides many advantages including: remote location of the laser source (which also means remote location of heat sources, a critical requirement for many applications); easy accommodation of several laser sources, including gas lasers and high--power, low--cost fiber pigtailed laser diodes; and variation of source wavelength without disturbing the pinholes. The principal advantages of this mapping system over existing methods are its small size, minimum number of critically aligned components, and remote location of the laser sources.Ph. D.
12
Hui, Tak-wai. "Solder paste inspection based on phase shift profilometry." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39558411.
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Hui, Tak-wai, and 許德唯. "Solder paste inspection based on phase shift profilometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39558411.
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Deng, Fuqin, and 鄧輔秦. "Computational surface profilometry and its applications in semiconductor inspection." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206340.
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Non-contact surface profilometry techniques, especially the phase-measuring profilometry, have been evolved dramatically over recent years. Besides the simple triangulation configuration with a fringe pattern projection system and digital imaging system, efficient computational surface profilometry techniques have also drawn tremendous attention from both academia and a wide range of applications. In the semiconductor industry, high-precision and high-speed, automated optical inspection systems are urgently needed to ensure high quality of semiconductor devices and yield improvement on the production and assembly line. However, by assuming the measured object to be stationary, conventional approaches are not suitable for surface profilometry of moving objects. Moreover, different sources of error such as the low contrast fringe patterns on the measured object, the unevenness in the illumination and the perspective projection effect from the optics will decrease the performance of surface profilometry.
To meet these challenges, we have built fringe pattern projection prototypes with projector and camera arrays for surface profilometry of moving objects along the conveyor belt. This design helps to enlarge the field of view with parallel processing. In addition, we have presented an optimization framework to investigate the sources of the error for surface profilometry and generalize various computational surface profilometry approaches under different scenarios.
Under this framework, first, we investigate two important factors determining the precision of surface profilometry, namely, the condition number of the phaseshift matrix and the fringe contrast within the images of the projected fringe patterns. Then, a regularized phase-shift algorithm has been proposed to improve the reconstruction results at the low contrast regions such as on the substrate of the semiconductor devices. Second, we study the intensity fluctuation caused by the uneven illumination for surface profilometry of moving objects. After that, an illumination-reflectivity-focus model has been suggested to describe the unevenness and an illumination-invariant phase-shift algorithm has been developed to handle this uneven illumination effect. Third, the perspective projection effect from the optics also affects the accurate phase-shift estimation for a moving object. Therefore, we propose a general polynomial phase-measuring profilometry model to establish the relationship between the phase-shift and height variation for each measured point. Accordingly, a polynomial phase-shift algorithm with error compensation technique has been put forward to improve the performance of the surface profilometry for moving objects.
Both simulation and real experiments from the prototype have been conducted to verify the improvement on the performance of the proposed methodologies. Furthermore, these research results have demonstrated the effectiveness and efficiency of the presented optimization framework for investigating the sources of error for surface profilometry. Moreover, the proposed computational surface profilometry techniques and the corresponding fringe pattern projection systems have been used in automated optical inspection systems for yield improvement on the production line in the semiconductor industry.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
15
Berryman, Fiona. "Fourier transform profilometry for measuring back shape in scoliosis." Thesis, University of Wolverhampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430997.
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Lindström, Tomas. "Characterization of interfaces by elastic light scattering and profilometry /." Uppsala : Acta universitatis upsaliensis, 1999. http://catalogue.bnf.fr/ark:/12148/cb392991128.
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Schwerdtfeger, Jan Vladimir. "Statistical heterogeneities of plastic deformation : an investigation based on surface profilometry." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/14363.
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In this Thesis we use atomic force microscopy (AFM) and scanning white light interferometry (Zygo) to investigate the spatial heterogeneity of plastic flow in crystalline materials. To this end we analyze one-dimensional surface profiles obtained from surface maps of deformed Alkali Halide single crystals. The Alkali Halides investigated were potassium chloride (KCI) and lithium fluoride (LiF), both of high purity. In the case of LiF also irradiation hardened LiF was investigated. For the deformed surfaces of the pure Alkali Halides we find self-affine behaviour with an exponent of about ζ=0.7..0.8 indicating long-range correlated patterns in the underlying strain field. No intrinsic limit to the scaling is found and the combination of AFM and Zygo allow us to assess the exponent over almost 6 orders of magnitude, from the mm down to the nm scale. We also find power-law behaviour for the probability density function of the step height p(s) and the exponent found to describe the power-law best over about 3 orders of magnitude is about T=-1.5. For p(s) an intrinsic limit is found towards larger surface step sizes. For irradiated LiF a different behaviour is observed for low deformations where strain softening leads to the emerging of characteristic step heights rather than scale-free behaviour. Towards larger strains the scale free behaviour with an exponent of T=-1.5 is recovered.
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Trail, Nicholas. "Imaging Profilometry For In Situ Measurement of Plasma Spray Coating Thickness." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/560844.
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Thermal Barrier Coatings (TBCs), and plasma spray coatings in general, require critical control over the deposited thickness to achieve reliable coating performance. Currently, the plasma spray industry quantifies thickness by sampling the part before and after TBC deposition. Approximate thickness is thus inferred from previous runs. However, process variability can allow errors to propagate in this result that leads to wasted time and resources, and can ultimately lead to non-reliant coatings. To this end, an in situ optical fringe profilometer is developed that enables coating thickness measurements across a 2-dimensional surface. The initial profilometer concept is explored through requirements and trade studies, leading to a hardware and algorithm design family and prototype build to capture and compare real-world data to simulation and model predictions. This initial result shows a viable path-forward and the ability to achieve micrometer-scale depth resolution. Modifications and alterations to the in situ profilometer are then explored to improve the performance limits achievable. In specific, industrial spray coatings operate by dropping fine-grain media into a high pressure gas line aimed through a plasma torch to impart enough thermal and kinetic energy to stick to the part surface. This presents a challenging operational environment for an optical depth measurement sensor, working with a variable high-temperature blackbody stray light source; constant part rotation and plasma gun movement; and a non-isolated vibration environment. As such, the concept of the profilometer is further adapted specific to this end-purpose, by developing and reviewing both dual-fringe projection and plenoptic imaging. These techniques allow an improvement to both the system micro- and macroscopic depth retrieval limits, allowing a method to solve for an extended range of phase ambiguities and relax object focus requirements (respectively). The end result is a system concept and algorithm design that presents a feasible manner for automated in situ geometry and depth measurements in the plasma spray industry. The in situ fringe profilometer work described herein allows a flexible path to recover object depth information remotely, and is especially relevant for asymmetric and complex non-planar geometries, which are experiencing renewed interest with additive manufacturing processes and generally quite common to the thermal spray industry.
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Watts, Richard Adrian. "The optical response of metallic diffraction gratings." Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361343.
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Yalla, Veeraganesh. "OPTIMAL PHASE MEASURING PROFILOMETRY TECHNIQUES FOR STATIC AND DYNAMIC 3D DATA ACQUISITION." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/348.
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Phase measuring Profilometry (PMP) is an important technique used in 3D data acquisition. Many variations of the PMP technique exist in the research world. The technique involves projecting phase shifted versions of sinusoidal patterns with known frequency. The 3D information is obtained from the amount of phase deviation that the target object introduces in the captured patterns. Using patterns based on single frequency result in projecting a large number of patterns necessary to achieve minimal reconstruction errors. By using more than one frequency, that is multi-frequency, the error is reduced with the same number of total patterns projected as in the single frequency case. The first major goal of our research work is to minimize the error in 3D reconstruction for a given scan time using multiple frequency sine wave patterns. A mathematical model to estimate the optimal frequency values and the number of phase shift patterns based on stochastic analysis is given. Experiments are conducted by implementing the mathematical model to estimate the optimal frequencies and the number of patterns projected for each frequency level used. The reduction in 3D reconstruction errors and the quality of the 3D data obtained shows the validity of the proposed mathematical model.
The second major goal of our research work is the implementation of a post-processing algorithm based on stereo correspondence matching adapted to structured light illumination. Composite pattern is created by combining multiple phase shift patterns and using principles from communication theory. Composite pattern is a novel technique for obtaining real time 3D depth information. The depth obtained by the demodulation of captured composite patterns is generally noisy compared to the multi-pattern approach.
In order to obtain realistic 3D depth information, we propose a post-processing algorithm based on dynamic programming. Two different communication theory principles namely, Amplitude Modulation (AM) and Double Side Band Suppressed Carrier (DSBSC) are used to create the composite patterns. As a result of this research work, we developed a series of low-cost structured light scanners based on the multi-frequency PMP technique and tested them for their accuracy in different 3D applications. Three such scanners with different camera systems have been delivered to Toyota for vehicle assembly line inspection. All the scanners use off the shelf components. Two more scanners namely, the single fingerprint and the palmprint scanner developed as part of the Department of Homeland Security grant are in prototype and testing stages.
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Widjanarko, Taufiq. "Hyperspectral interferometry for single-shot profilometry and depth-resolved displacement field measurement." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8349.
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A new approach to the absolute measurement of two-dimensional optical path differences is presented in this thesis. The method, which incorporates a white light interferometer and a hyperspectral imaging system, is referred to as Hyperspectral Interferometry. A prototype of the Hyperspectral Interferometry (HSI) system has been designed, constructed and tested for two types of measurement: for surface profilometry and for depth-resolved displacement measurement, both of which have been implemented so as to achieve single shot data acquisition. The prototype has been shown to be capable of performing a single-shot 3-D shape measurement of an optically-flat step-height sample, with less than 5% difference from the result obtained by a standard optical (microscope) based method. The HSI prototype has been demonstrated to be able to perform single-shot measurement with an unambiguous 352 (m depth range and a rms measurement error of around 80 nm. The prototype has also been tested to perform measurements on optically rough surfaces. The rms error of these measurements was found to increase to around 4× that of the smooth surface. For the depth-resolved displacement field measurements, an experimental setup was designed and constructed in which a weakly-scattering sample underwent simple compression with a PZT actuator. Depth-resolved displacement fields were reconstructed from pairs of hyperspectral interferograms. However, the experimental results did not show the expected result of linear phase variation with depth. Analysis of several possible causes has been carried out with the most plausible reasons being excessive scattering particle density inside the sample and the possibility of insignificant deformation of the sample due to insufficient physical contact between the transducer and the sample.
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Zhang, Hong. "The phase shifting technique and its application in 3-D fringe projection profilometry." Thesis, Liverpool John Moores University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310141.
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Eisenburger, Michael Gregor Walter. "Studies on dental erosion and attrition using a new ultrasonication and profilometry technique." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247553.
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Neeley, Alexandra. "Characterizing the Localized Corrosion of AA7075-T6 and AA2024-T3 by Optical Profilometry." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1330391114.
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Murthy, M. S. Narasimha. "A study of the application of phase mapped profilometry for measuring optic disc topography." Thesis, University of Aberdeen, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484245.
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Taudt, Ch, T. Baselt, B. Nelsen, H. Assmann, A. Greiner, E. Koch, and P. Hartmann. "Evaluation of the thermal stability of a low-coherence interferometer for precision surface profilometry." SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A34883.
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Manufacturing of precise structures in MEMS, semiconductors, optics and other fields requires high standards in manufacturing and quality control. Appropriate surface topography measurement technologies should therefore deliver nm accuracy in the axial dimension under typical industrial conditions. This work shows the characterization of a dispersion-encoded low-coherence interferometer for the purpose of fast and robust surface topography measurements. The key component of the interferometer is an element with known dispersion. This dispersive element delivers a controlled phase variation in relation to the surface height variation which can be detected in the spectral domain. A laboratory setup equipped with a broadband light source (200 - 1100 nm) was established. Experiments have been carried out on a silicon-based standard with height steps of 100 nm under different thermal conditions such as 293.15 K and 303.15 K. Additionally, the stability of the setup was studied over periods of 5 hours (with constant temperature) and 15 hours (with linear increasing temperature). The analyzed data showed that a height measurement of 97.99 ± 4:9nm for 293.15 K and of 101.43 ± 3:3nm for 303.15 K was possible. The time-resolved measurements revealed that the developed setup is highly stable against small thermal uctuations and shows a linear behaviour under increasing thermal load. Calibration data for the mathmatical corrections under different thermal conditions was obtained.
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Ersvik, Erik, and Roj Khalid. "Milling in hardened steel - a study of tool wear in conventional- and dynamic milling." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255646.
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Milling is a commonly used machining process where a rotating cutter removes material from the workpiece. In recent years, attention has been turned towards so called dynamic milling methods which differ from the conventional way of milling. Dynamic milling normally uses, as opposed to the conventional way, more of the axial cutting edge, smaller radial depth of cut, significantly higher cutting speed and feed per tooth. The method has demonstrated potential to save both time and money under specific circumstances, for manufacturing companies.This thesis was conducted at ISCAR Sverige AB in Uppsala, Sweden. ISCAR Metalworking is a full service supplier of carbide cutting tools. The objective is to establish if there are benefits with dynamic milling methods with regard to material removal rate and lifetime of the tool by experimentally investigating and comparing tool wear that occur with conventional- and dynamic milling methods in hardened steels. Tools used were ISCAR’s MULTI-MASTER end mills, MM A and MM B, and the hardened steels were Hardox 600 and Dievar. Analysis was performed by using a USB-microscope, scanning electron microscope (SEM) and a Wyko-profilometer. The results of this study show that dynamic milling parameters can give several benefits regarding tool life and material removal rate. When machining in Hardox 600 and Dievar, both end mills were able to achieve a higher material removal rate and lifetime with dynamic parameters compared to more conventional ones. MM A outperformed MM B in Dievar, but the results were reversed in Hardox, MM B performed better. Results from the profilometry analysis showed that in Dievar, the dynamic parameters generated a smoother surface while the surface results from Hardox were more equivocal. The main conclusion was that milling with dynamic parameters is generally more advantageous and should be utilised, if possible.
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Vacula, Daniel. "Automatizace metody měření povrchových struktur reflexním digitálním holografickým mikroskopem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228893.
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Reflected-light digital holographic microscope developed at IPE FME BUT uses off-axis holography principle and low spatial and temporal coherence illumination. Microscope allows reconstruction of the image amplitude and the image phase, which can be handled in real time. The only limiting factors are imaging speed of the detector and computer performance when processing holograms. Reconstruction of image phase and amplitude allows high-resolution profilometric measurements in the vertical axis direction. This thesis deals with the automatization of profilometric measurement method proposed in [2]. Proposed method uses the combination of the image phase and the image amplitude for the measurement of specimens with surface structure the vertical size of which cause the uncertainty of the image phase by a factor of 2pí. Futher the thesis deals with the construction design of the illumination system of the microscope and its realization together with experimental verification of functionality of proposed method automatization.
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Bilmont, Marsha F. "FURTHER INVESTIGATIONS INTO SURFACE STRUCTURE AND THE BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION (LIGHT-SCATTER, ROUGHNESS, PROFILOMETRY)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275398.
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Xu, Wu-Xian, and 許武憲. "Optical heterodyne profilometry." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/03673622042849909740.
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碩士國立交通大學
光電工程研究所
84
We utilized the principle which foci are different for parallel polarized beam and vertical polarized beam passing through birefringent lens ;the beamwhich it is focused on the sample surface and acts astest beam ; the other beam which is collimated and illuminates a small area on the sample surface and acts as reference beam . since E-O modulated , there is frequency difference between the two orthogonal linear polarized beams , then it measured phase change by a differential interferometer and is to infer roughness by phase chang . this arrangement is simple and analyze easily ; it do not damage the sample surface and relatively cheap to probe-roughness senor.
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Chen, Yo-Wei, and 陳佑威. "Shadow Moire Profilometry." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51260091131506415658.
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碩士國立中興大學
機械工程學系所
98
When the specimen was examined through the grating, the lines of the grating were observed, as well as the changes of the grating’s shadow according to the specimen’s profilometry. The lines and shadows from the grating together produced a moire fringe pattern; it is called a shadow moire pattern. The method of calculating the profilometry using the moire is called the shadow moire. This research was to measure a specimen’s profilometry using the phase shift technique according to shadow moire. This research proposes that using the flatbed scanner to record shadow moire pattern will reduce the noise on the recorded images. A flatbed scanner is an inexpensive and easily obtained high quality digital image recorder that records images. Furthermore, the entire specimen’s profilometry can be calculated by the phase shift technique and the phase-unwrap technique. The ±137μm white board was chosen to be specimen in order to let grating’s shadow to fall on specimen in this research. The last research results were compared by the measurements of Profilometry from CMM and Laser probe. The uncertainty was claculated from this result.
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Tsai, Cheng-Yu, and 蔡政育. "Profilometry Using Depth from Defocus." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29267095306990575864.
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碩士國立中興大學
機械工程學系所
99
In this paper, three dimension shape is recovered by blurring images, the blurring images can be adjusted by three camera parameters, namely focal length, aperture diameter, distance between the lens and the image detector plane, in this study, we get the defocusing images by adjusting the image detector plane, and then calculate the wavelet coefficient power spectrum of two different defocusing images recover three dimension shape, the relationship with differences in size of the power spectrum and the degree of blur, the fluctuation of surface will affect the value of this difference. The algorithm of this paper will use the wavelet function, wavelet function in the frequency domain can be regarded as a bandpass filter, the purpose of the use of wavelet transform is to reduce the calculation of Fourier transform producing the border effect, the focus image through the point spread function can produce the defocusing blur images, the power spectrum of two images in the frequency domain differences in the form of exponential decay, the experimental results show that using a high magnification lens and shooting a small object can be a complete reconstruction of the object morphology.
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Chen, Shang-Fang, and 陳聖芳. "THE STUDY OF HETERODYNE PROFILOMETRY." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/73557680103167163553.
Full textAbstract:
碩士中原大學
機械工程研究所
81
Measuring surface profile can not only know the smoothness of surface ，but also know the surface roughness if sampling points are more enough and sensitivity is high enough．There are many applications such as mirrors coatings、polishing、 friction、 lubrication and so on． Heterodyne profilometry has the advantages of high sensitivity and excellent spatial resolution and non-contact measurement．This paper uses heterodyne profilometry to measure surface profile．The ideal hight sensitivity of system is ±35 angstrom at present，which can be improved to angstrom sensitivity and a lateral resolution of 0.5mm，which can be improved to 1∼3μm ．The system is insensitive to the reflectance of the sample，and no separate reference surface is needed．Heterodyne interferometry makes high frequency optical wave bringing with low frequency signal ． The optical path difference (OPD)concept is used to determind the hight variations of surface．
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Wu, Zhong-Ying, and 吳忠穎. "Phase-measuring profilometry of 3D objects." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/92162403252672758663.
Full textAbstract:
碩士國立交通大學
顯示科技研究所
94
The application of surface profile measurement is very extensive, such as product testing, reverse engineering, and so on, while how to make the measurement fast and accurate has been crucial. In this paper, we deduce the surface profile of a 3D diffuse object by measurement of the phase distribution across the image of a projected grating deformed by the surface. As a detailed evaluation, we first simulated the experimental structure by using MATLAB software, and explored possible error produced by the corresponding approach. Finally, we have built up the system, tested over different object forms, and compared the results with simulation. An effective phase-measuring profilometry of 3D objects has been realized through this thesis study.
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Chen, Wei-jen, and 陳煒仁. "Projected Fringe Profilometry using Diffractive Elements." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/82055859832032318124.
Full textAbstract:
碩士國立中山大學
材料科學研究所
94
A technique using diffractive elements for finding the absolute shape of a large-scale object is proposed. An accurate projected fringe profilometry can be built by applying the holographic technique in this system. The advantages of using the presented technique for projected fringe profilemetry are : (1) a large depth of field ; (2) very low fringe distortion ; (3) a compact design for the measurement system ; (4) high accuracy ; (5) fast measurement speed.
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HSU, CHIA-YU, and 許嘉佑. "Mask optimization for fringe projection profilometry." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/22y48v.
Full textAbstract:
碩士國立高雄應用科技大學
光電與通訊工程研究所
106
In this paper, a mask using image processing is proposed to extract the fringe region in the depth of field of the system in the fringe projection profilometry. This mask can more accurately obtain the edge of the object in the image. This mask algorithm is used to explore the help of fringe message control for various fringe projection profilometry. It is also proposed to use the fringe mask to search for fringe information in the near-focus area. A fringe mask that matches the fringe depth of field to increase measurement speed. The range of the focal length of the object to be tested in the reconstructed image can be screened by the design of the mask. The scope of the screening is used to find two reconstruction methods. The first method is to use the curve with a wide range of fringe before and after the depth of field. The original shape of the object to be tested is reconstructed in a combined manner. The difference between this method and Fourier transform profilometry is that the range of filtered depth of field is done in the time domain. The second way is to find the data point of the object to be tested that is very close to the focal length, and find out the depth information of the object to be tested by scanning to superimpose the shape of the object to be tested.
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Helg, Tina Louise. "Novel Interferometric Techniques in Profilometry and Spectrometry." 2000. http://hdl.handle.net/2292/603.
Full textAbstract:
The work in this thesis is in the fields of profilometry and Fourier transform spectrometry. Deformation measurement of diffuse objects by phase stepping was achieved by thermal frequency drift in a HeNe laser. The system was easy to construct, required no specialised components, was immune to the effects of piezo-actuator hysteresis, and was capable of producing phase maps in which noise was less than 1/20λ. A method was proposed for measuring absolute surface profile by scanning frequency over the range of a white light source. The coincidence technique of coherence radar was used to measure surface profiles in three dimensions to micron accuracy. Spatial techniques were developed to process the large data set quickly and efficiently. A novel Fourier transform spectrometer was developed to measure the spectrum of narrowband light sources. Heterodyning techniques gave a resolution of 0.01nm with a free spectral range of =2.5nm. The Sagnac common path design afforded immunity to vibration. The mode structure and mode hopping characteristics of a typical laser diode were measured as a function of diode injection current. An improved Fourier transform spectrometer was developed. Based on a Michelson interferometer. The instrument could resolve to 0.013nm over a =3nm free spectral range. Instrument operation was simplified and functionality was extended to non point sources.
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李勇民. "Microscopic surface profilometry by fringe projection method." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/34740978605374358701.
Full textAbstract:
碩士國立中興大學
機械工程學系
92
This paper describes the usage of fringe projection method and triangulation principle for three dimension surface profile measurement of micro component. In this method, Gray-code and Phase-shifting cosinusoidal pattern are projected onto micro-component surface by a programmable liquid crystal display (LCD) and a stereo microscope. The Gray-code method is exploited to detect discontinuities of the surface, whereas Phase-shifting technique allows the measurement of fine surface details. This system use mathematical model of mapping function to compensate various systematic error and evaluate 3D profile of micro-component.
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Wang, Chun-Chieh, and 王俊杰. "Noninterferometric Widefield Optical Profilometry and Its Applications." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/37172490109641910506.
Full textAbstract:
博士國立中正大學
物理所
95
This thesis introduces the study of membrane dynamics of living cells by using “non-inteferometric widefield optical profilometry (NIWOP).” NIWOP obtains surface topography without contacting and scanning the sample surface. It is also compatible to fluorescence labeling techniques. Therefore, it is very suitable for the study on cell membrane dynamics and cell physiology. The principle of NIWOP is based on widefield optical sectioning microscopy (WOSM) and differential confocal microscopy (DCM). The former achieves optical sectioning ability by projecting a high-spatial-frequency grid pattern onto the focal plane. When three images with the grid pattern at spatial phases 0, 2p/3, and 4p/3, are captured and processed with the homodyne detection principle, the grid pattern is removed and the out-of-focus images are eliminated. Therefore an optically sectioned image similar to that provided by a confocal microscope is obtained. Because the axial response curve of WOSM is very closed to that of confocal microscopy, one can apply the principle of DCM to obtain nanometer depth resolution on sample surface. That is, to place the sample surface into the linear region of the axial response curve of the sectioning microscopy. In the linear region, the optical signal is very sensitive to surface height variations. NIWOP has following advantages: first is the nanometer depth resolution. The optimal depth resolution of NIWOP was 10-nm by current experimental setup. Second is the micrometer dynamic range. For example, if we use an objective with a 1.2 numerical aperture and project a periodic grid pattern with a 0.5 mm-1 spatial frequency onto the sample surface, the dynamic range is about 1.3 mm. Third is high image acquisition speed. The image acquisition speed is 20 frame/min at 1002×1004 pixels image format. It is restricted by the mechanical shift speed of grid pattern and computer processing speed. This acquisition speed is fast enough for the study of cell membrane dynamics. The most important advantage is that all components of NIWOP can be added outside a conventional microscope. Therefore, it is compatible with other optical contrast mechanism, such as fluorescence and polarization microscopy, etc. In this thesis, I will introduce the observation of membrane ripples by using NIWOP, and the study on the correlation between membrane ripples and underlying cytoskeletons by combining NIWOP with fluorescence microscopy. Besides, we also use a drug called cytochalasin D, an actin-polymerization inhibitor, to confirm that the membrane ripples confine the structure of underlying actin filaments. According to the observation, we propose a model to describe the formation of this membrane ripple structure. We also use a fibronectin-coated latex bead to study the correlation between the motion of extra-cellular proteins and underlying cytoskeletons. According to the three-dimensional motion of the fibronectin-coated bead on the membrane, we can estimate the treadmill speed of actin monomers on the actin filament and the elongation rate of the actin filament branch. With the nanometer depth sensitivity of NIWOP, we also observe the surface variation during endocytosis. This surface variation is just within tens or hundreds of nanometers, therefore it is not possible for conventional optical microscopy to identify the site or to observe the process. By the simultaneous and quantitative measurements of the axial movement of endocytic bovine serum album coated gold nano-particle and membrane height variations, we are sure that the endocytosis occurs. Combing fluorescence microscopy, we also study the role of actin aggregation around the endocytic vesicle during the endocytosis process. In addition to the studies on membrane dynamics, we also employ super-resolution NIWOP to study the dynamics of cancer-cell filopodia. The principle of super-resolution NIWOP is based on the excellent height sensitivity of NIWOP that can obtain extra image contrast by the topography of sample surface. It has been demonstrate that the lateral resolution can be improved to l/7, if the image restored by a maximum likelihood estimation (MLE) algorithm. By using this technique, we clearly observe small filopodia that cannot be identified by conventional bright-field microscope. We also measure the elongation and shrinkage rates of cancer-cell filopodia without using exogenous contrast agents. Besides, combining the principles of differential measurement and Fabry-Parot interferometry, we also invent a novel technique “differential optical sectioning interference microscopy (DOSIM)” that can simultaneously obtain thickness and refractive index of transparent thin films with diffraction-limited lateral resolution. Because this work is over the issue of this thesis, it will be discussed in the appendix.
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Song, Chun-Hung, and 宋俊宏. "Profilometry of spherical lens using flash interferometry." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26452047685312807509.
Full textAbstract:
碩士國立中興大學
機械工程學系所
99
The spherical lens elements have played an important role in the applications of current optical products up to now. Therefore, it is significant for the performance of the entire optical systems to enhance the detection of the surface profile of the spherical lens and to improve the manufacturing precision of the optical systems. After several years’ development in techniques for the measurement of the surface profile of the spherical lens, the phase shifting methods have commonly been used in high precision measurement. However, there are some obstacles to the methods because environmental noise prohibits conventional phase shifting methods. Therefore, I adopted the instantaneous interference methods to measure the surface profile of the spherical lens and to accomplish the objectives of making high precision measurement of the surface profile of the spherical lens. Used the Fizeau interferometry to capture single interference fringes and used the Fourier interferometer techniques to reconstruct the surface topography contours. By comparing the results with the results I got by using the ZYGO interferometer, I found that the first results are similar to the second results. As a result, the feasibility of the experimental architecture was verified.
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Huang, Jun-shan, and 黃俊善. "Projected Fringe Profilometry for dynamic micro-scale measurements." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/2dgpz5.
Full textAbstract:
碩士國立中山大學
材料科學研究所
95
A novel technique using projected fringe profilometry with pulsed illuminations for finding the absolute shape of a dynamic object, which is vibrating with high frequency, is proposed. The proposed method can accurately describe the observed 3D shape at a sequence of time. Even though the tested object vibrates up to 10K-Hz, the proposed method can accurately describe the observed 3D shape at any specific time. Depth accuracy better than one part in ten thousandths of the field of view can be achieved even with excessive image noises. Furthermore, the light source is temporally incoherent and spatially coherent, providing a speckle-free and a large depth-of-focus illumination. Thus, a highly accurate, non-scanning projected fringe profilometer with large depth measuring range for dynamic measurements can be realized.
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Chang, Yi-Wei, and 張奕威. "Research on Multi-wavelength Differential Confocal Surface Profilometry." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/52nj68.
Full textAbstract:
博士國立臺北科技大學
機電科技研究所
101
This study presents a novel Multi-wavelength Differential Confocal surface profilometer using broadband light source, dispersion chromatic objective and two color line CCD devices. Optical confocal microscopy for surface profilometry has become extremely important due to its high longitudinal measurability range and excellent vertical resolution. In this study, the system was developed to establish a multi-wavelength line chromatic confocal mathematical model and generate accurate wavelength-to-depth conversion for in-situ 3-D profile measurement without the need for time-consuming vertical scanning. In this method, two CCD are configured at two different designated focusing positions, which are controlled by CCD focus position. A depth-focus response curve can be established by two colors CCD with Red, Green and Blue ratio curve. In addition, using the principle of differential confocal, an output function is reestablished as the ratio of subtraction and sum values of the two color detectors’ responses to reduce the surface reflectance influence. To test the performance of the developed system, an accurate step-height target and some industrial micro semiconductor components were measured to verify measurement accuracy and repeatability. The depth measurement resolution can reach up to 0.3 µm and the maximum measurement error was verified to be within 0.6% of the overall measuring range without vertical scan.
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Huang, Bo-Chin, and 黃柏欽. "Projected Fringe Profilometry Techniques Using for Specular Surfacess." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/ftzh38.
Full textAbstract:
碩士國立中山大學
材料與光電科學學系研究所
103
A fringe projection method for specular is presented. For specular objects, only part of the refracted light can be detected by a CCD camera. Thus, the typical projected fringe profilometry cannot be used for specular surfaces. In the proposed method, a fringe pattern is posited in front of the specular surface. A virtual image therefore is produced behind the specular surface. Fringes on the virtual image are deformed by topography of the specular place the object. Thus, phase of the deformed fringes is desirable to retrieve the profile of the specular surface. The measurement setup is simple and robotic, and the computation cost is low. Its one-shot measurement property also makes it possible to inspect dynamic objects.
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Liao, Chu-Chin, and 廖至欽. "Calibration of a Digital Fringe 3-D Profilometry." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/67448594469344297003.
Full textAbstract:
碩士國立臺北科技大學
自動化科技研究所
92
An effective calibration method has been successfully developed to significantly increase the accuracy of 3-D surface measurement using digital fringe projection and phase-shifting method. In digital fringe projection, the image intensity and distribution of the sinusoidal fringe patterns projected on the measured surface may be affected by lens distortions and image aberrations. The phase difference calculated by the phase shift principle can be influenced by this problem and become nonlinear to the optical phase difference (OPD) existing between the surface profiles. This research has deployed a 3-D calibration method to obtain accurate system parameters for 3-D surface measurement. The calibration method utilizes a known accurate 3-D calibrating block and projection mathematical models for identification of the system parameters. Accurate clouds of 3-D data points can be obtained by a 3-D mapping method between object space and image coordinates in cooperating the phase difference. The 3-D measurement accuracy can be significantly enhanced by 2.1 times in comparison with un-calibrated cases while the measuremnet repeatability can be maintained within 25μm micrometers.
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Lee, Cheng-He, and 李承和. "The Application of Homography in Line Laser Profilometry." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/87436853005040559394.
Full textAbstract:
碩士國立中興大學
機械工程學系所
103
The purposeof this studydevelop a novel non-contact measurement system of three-dimensional and calibration.Line laser triangulation measurement method which architecture is line lasers, cameras, measurement.This method can utilize thetriangular geometry, through digital images to measure the objects in space coordinate information.First, we set up a camera calibration model to get the cameracoordinates and image coordinates and world coordinates betweenrelationship of coordinate conversion.Again we have to make line laser tothin and filtering, finally, we directly use the intersecting planes of measuring object planeand the line laser projection plane betweenthe digital image plane geometry translation relationship,to obtain projection relationship of the two planesbyHomography, complete a simple and efficient calibration procedures to measure the contours of three-dimensional objects.
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Hou, Cheng-Cheng, and 侯政呈. "Single interference fringe image phase retrieval in profilometry." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/91289977709934925358.
Full textAbstract:
碩士國立中興大學
機械工程學系所
102
The present study employs a single interference pattern phase retrieval to collect data on surface profilometry. Since single im- ages have fewer environmental constraints than a multi-step phase shift method, it is possible to glean phase data from the interfer- ence pattern generated by this method using phase measurement techniques. This data can subsequently be converted into a surface profilometry of an object. However, calculating the phase through the Fourier transform method results in frequency leakage, if the edges of the interference pattern lack sufficient continuity or pe- riodicity. This diminishes the resolution of the surface edge profilometry data and leads to differences from the actual profilometry. This study aims to alleviate the loss of resolution problems caused by frequency leakage, by reconstructing the edge fringes using the Papoulis Gerchberg algorithm. By improving the algorithm and comparing the efficiencies of various filters, re- constructions to the initial interference pattern were found to smooth out the edge and increase the speed of convergence, al- lowing for an analysis of different pattern densities. The first portion of the design involved the use of a fringe projection method to project simulated interference patterns, using a five step phase shift method to verify the results of Papoulis Gerchberg calculations and improve the effectiveness of P-G on a single image. The second portion consisted of acquiring surface profilometry by creating interference patterns with green mono- chromatic light, and deriving the phase using a Fourier transform.
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Chang, Chia-Yuan, and 張家源. "White Light Phase Shifting Interferometry for Surface Profilometry." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/72572170054195677152.
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TSAI, YU-NAN, and 蔡佑男. "Three-Dimension Profilometry of a Plaster Tooth-Model." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/59227992653725981789.
Full textAbstract:
碩士中原大學
機械工程研究所
90
Abstract The application of the three dimensional measurement has been widely used in the industry. Currently, three-dimensional digital scanning technique has shown different faces and significance in various fields, such as multimedia model construction, digital preservation of cultural art etc. But, the application in the medical field is still waiting to be developed. In this research, using non-contact optical measurement, along with high-order polynomial three-dimension space mapping function technique, five-axial movement, 3-D coordinates conversion, and seven scanning modes have been developed to measure tooth plaster-models with highly complex shapes. The scanned data can be used in medical treatment, personal medical record etc. This measurement system with a 30mm 40mm 60mm -measurement space uses crosshair laser diode generator matching platform movement to accomplish measurement space calibration. As suggested denture mold articles, the error margin should be within 0.025mm~0.05mm. In this research, the data from measuring standard objects was measured with CMM measurement platform to have accuracy of 0.04mm, which satisfies the requirement of practical applications. Currently, this kind of systems is developed only by German Seimens. But, this system emphasizes on oral chamber scanning, therefore, can only be used in single-tooth small range scan, which makes the scanning of the whole tooth-plaster-model mold structure impossible. Also, this system from overseas is expensive, which prevents it to be widely used. I am anxious to see our countrymen develop our own systems to lower the production cost for it to be widely used in all fields and levels.
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LIN, YI-AN, and 林奕安. "Amplitude extraction method for 2D pattern projection profilometry." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/d4a739.
Full textAbstract:
碩士國立高雄應用科技大學
光電與通訊工程研究所
106
In this paper, Amplitude extraction method is proposed. Projection and capture of images using a common optical axis path with a shallow depth of field lens. The object is sampled at each separation distance. Use filtered background image and fringe phase. The curve of the fringe changes with the depth of field of the lens. Then use the smoothing filter on the image to smooth the curve, obtain the amplitude without noise, and then use the amplitude of all the sampled images of the object to be tested, and use the quadratic function to find the maximum amplitude position. Then convert this position to the original height to restore the original image position. However, this method will not encounter the problems of the Fast Fourier Transform method, because the leakage problem caused by the Fast Fourier Transform has a problem of amplitude expansion after band-pass filter uses a narrow bandwidth limited bandwidth range, and the error edge is judged as the high frequency fringe. Then restore the edges together. In the new way, the amplitude of the image can be captured more quickly, and the surface topography of the object can be converted using all amplitudes.
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Chen, Chao-nan, and 陳昭男. "Research of Chromatic Confocal Three-dimensional Surface Profilometry." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/7ndgd6.
Full textAbstract:
碩士國立臺北科技大學
自動化科技研究所
97
An on-line 3-D surface profilometer for micro surface profiles with a long range and high resolution measurement was successfully developed using innovative slit-scan multi-wavelength confocal microscopy. In conventional confocal microscopy, vertical scanning of the object’s surface by either stage depth movement or shifting of the objective lens is extremely time consuming, thus resulting in unacceptable efficiency for on-line inspection. To overcome this, in this research, a multi-wavelength confocal microscope employing a broadband light source in combination with a chromatic dispersion objective was developed to generate an accurate wavelength-to-depth conversion for 3-D profile measurement. A specially designed objective is capable of modulating a broadband light to produce the axial chromatic dispersion and various focus on a series of continuous depths along the z-axis and then obtain the corresponding reflected light spectrum from the object’s surface. The reflective spectrum is spatially filtered by a slit and then a peak position with respect to the filtered spectrum for every measuring point along the scanning line is detected by a spectral image sensing unit for generating the sectional profile of the measured surface efficiently and accurately. By doing this, the vertical scanning operation can be completely avoided and its measurement time can be greatly shortened. By designing the objective, the depth measurement range can be ranged between few to several hundred micrometers and the depth measurement resolution can reach to 0.11% of the overall detection range. From the experimental test, it was confirmed that the maximum measurement error and repeatability can be controlled well within 0.3% of the overall measurement range. The measurement efficiency can be significantly improved for on-line automatic optical inspection (AOI).