Real Time 3d Surface Shape Measurement Using Fringe Projection And System Geometry Constraints
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Real Time 3d Surface Shape Measurement Using Fringe Projection And System Geometry Constraints
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Author : Xinran Liu
language : en
Publisher:
Release Date : 2019
Real Time 3d Surface Shape Measurement Using Fringe Projection And System Geometry Constraints written by Xinran Liu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Three-dimensional imaging categories.
Optical three-dimensional (3D) surface-shape measurement has diverse applications in engineering, computer vision and medical science. Fringe projection profilometry (FPP), uses a camera-projector system to permit high-accuracy full-field 3D surface-shape measurement by projecting fringe patterns onto an object surface, capturing images of the deformed patterns, and computing the 3D surface geometry. A wrapped phase map can be computed from the camera images by phase analysis techniques. Phase-unwrapping can solve the phase ambiguity of the wrapped phase map and permit determination of camera-projector correspondences. The object surface geometry can then be reconstructed by stereovision techniques after system calibration. For real-time 3D measurement, geometry-constraint based methods may be a preferred technique over other phase-unwrapping methods, since geometry-constraint methods can handle surface discontinuities, which are problematic for spatial phase unwrapping, and they do not require additional patterns, which are needed in temporal phase unwrapping. However, the fringe patterns used in geometry-constraint based methods are usually designed with a low frequency in order to maximize the reliability of correspondence determination. Although using high-frequency fringe patterns have proven to be effective in increasing the measurement accuracy by suppressing the phase error, high-frequency fringe patterns may reduce the reliability and thus are not commonly used. To address the limitations of current geometry-constraint based methods, a new fringe projection method for surface-shape measurement was developed using modulation of background and amplitude intensities of the fringe patterns to permit identification of the fringe order, and thus unwrap the phase, for high-frequency fringe patterns. Another method was developed with background modulation only, using four high-frequency phase-shifted fringe patterns. The pattern frequency is determined using a new fringe-wavelength geometry-constraint model that allows only two point candidates in the measurement volume. The correct corresponding point is selected with high reliability using a binary pattern computed from the background intensity. Equations of geometry-constraint parameters permit parameter calculation prior to measurement, thus reducing computational cost during measurement. In a further development, a new real-time 3D measurement method was devised using new background-modulated modified Fourier transform profilometry (FTP) fringe patterns and geometry constraints. The new method reduced the number of fringe patterns required for 3D surface reconstruction to two. A short camera-projector baseline allows reliable corresponding-point selection, even with high-frequency fringe patterns, and a new calibration approach reduces error induced by the short baseline. Experiments demonstrated the ability of the methods to perform real-time 3D measurement for a surface with geometric discontinuity, and for spatially isolated objects. Although multi-image FPP techniques can achieve higher accuracy than single-image methods, they suffer from motion artifacts when measuring dynamic object surfaces that are either moving or deforming. To reduce the motion-induced measurement error for multi-image FPP techniques, a new method was developed to first estimate the motion-induced phase shift errors by computing the differences between phase maps over a multiple measurement sequence. Then, a phase map with reduced motion-induced error is computed using the estimated phase shift errors. This motion-induced error compensation is computed pixel-wise for non-homogeneous surface motion. Experiments demonstrated the ability of the method to reduce motion-induced error in real-time, for real-time shape measurement of surfaces with high depth variation, and moving and deforming surfaces.
Real Time Full Field Range Sensing For Three Dimensional Surface Shape Measurement
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Author : Peirong Jia
language : en
Publisher:
Release Date : 2007
Real Time Full Field Range Sensing For Three Dimensional Surface Shape Measurement written by Peirong Jia and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
Three-dimensional (3-D) surface-geometry measurement using structured light is commonly used for digital modeling of an object or environment when the geometry is unknown. Digital fringe projection with phase-shifting has become an increasingly common measurement method as it is a full-field method to improve acquisition speed over point-by-point and line-by-line methods, and it encodes all lines in the pattern to reduce the ambiguity problem that occurs with multiple-line projection methods. However, fringe-projection phase-shifting techniques are still limited in the speed of measurement, partly due to the use of projected light patterns that require complex computation, or that require several steps of repeated measurements with several images in order to reconstruct the 3-D object surface. This doctoral dissertation addresses the development of new methods for real-time full-field range sensing by fringe-projection phase-shifting techniques, to use more efficient algorithms. It also addresses the design, calibration, and measurement-accuracy testing of a new full-field real-time range-sensing system based on the developed methods. A novel 3-D shape measurement technique, called triangular-pattern phase-shifting profilometry, is developed in this research. The proposed method utilizes triangular gray-level-coded fringe patterns and newly developed intensity-ratio generation algorithms, essential to reconstruct a 3-D object surface. The minimum number of measurements required to reconstruct an unknown 3-D object is two, which is less than the minimum number of measurements required for the traditional sinusoidal-pattern and trapezoidal-pattern phase-shifting methods. Compared with the sinusoidal-pattern and trapezoidal-pattern phase-shifting methods, the new method involves less processing because of the simple intensity-ratio computation used and because fewer images or measurement steps are required to reconstruct the 3-D object. Extension of the method by increasing the number of phase-shifting steps was found to increase measurement accuracy. An optimal value of pitch of the projected triangular fringe pattern was found for each extended method. Two error compensation methods, repeated phase-offset and intensity-ratio error compensation, are proposed to reduce the measurement error, mainly caused by fringe projection non-linearity and image defocus. Error reductions of 24.0% and 28.5% were achieved, respectively. An off-line 3-D shape measurement system and a real-time 3-D shape measurement system have been developed with the proposed triangular-pattern phase-shifting method.
A Real Time Multi Sensor 3d Surface Shape Measurement System
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Author : Mohammad Al Sa'd
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2011-10
A Real Time Multi Sensor 3d Surface Shape Measurement System written by Mohammad Al Sa'd and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-10 with categories.
This book presents a state-of-the-art multi-sensor, 3D surface shape measurement system that is based upon fringe projection/analysis and which operates at speeds approaching real-time. The system provides the flexibility to choose from amongst several different fringe profilometry methods and the ability to manipulate their settings interactively. The system has a wide variety of potential applications, including Metrology Guided Radiotherapy, 3D modelling and visualisation, verbatim replication, and reverse engineering. This book provides a comprehensive framework for producing such a novel optical profilometry system, including the associated hardware and software structures, camera synchronisation, crosstalk reduction, and complete system integration. Also, it presents and illustrates the specific techniques that were developed to fulfil the requirements of various optical profilometry applications.
Advanced Concepts For Intelligent Vision Systems
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Author : Salah Bourennane
language : en
Publisher: Springer
Release Date : 2008-10-05
Advanced Concepts For Intelligent Vision Systems written by Salah Bourennane and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-10-05 with Computers categories.
This book constitutes the refereed proceedings of the 10th International Conference on Advanced Concepts for Intelligent Vision Systems, ACIVS 2008, held in Juan-les-Pins, France, in October 2008. The 33 revised full papers and 69 posters presented were carefully reviewed and selected from 179 submissions. The papers are organized in topical sections on image and video coding; systems and applications; video processing; filtering and restoration; segmentation and feature extraction; tracking, scene understanding and computer vision; medical imaging; and biometrics and surveillance.
A Real Time Multi Sensor 3d Surface Shape Measurement System Using Fringe Analysis
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Author : Mohammad Saleh Al Sa'd
language : en
Publisher:
Release Date : 2011
A Real Time Multi Sensor 3d Surface Shape Measurement System Using Fringe Analysis written by Mohammad Saleh Al Sa'd and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Coded Optical Imaging
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Author : Jinyang Liang
language : en
Publisher: Springer Nature
Release Date :
Coded Optical Imaging written by Jinyang Liang and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
High Speed 3d Imaging With Digital Fringe Projection Techniques
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Author : Song Zhang
language : en
Publisher: CRC Press
Release Date : 2018-09-03
High Speed 3d Imaging With Digital Fringe Projection Techniques written by Song Zhang and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-09-03 with Computers categories.
Digital fringe projection (DFP) techniques are used for non-contact shape measurement of 3D images. In the rapidly expanding field of 3D high-speed imaging, the demand for DFP continues to grow due to the technology’s fast speed, flexibility, low cost, and high accuracy. High-Speed 3D Imaging with Digital Fringe Projection Techniques discusses the generation of digital fringe with digital video projection devices, covering a variety of core technical aspects. The book begins by establishing the theoretical foundations of fringe pattern analysis, reviewing various 3D imaging techniques while highlighting the advantages of DFP. The author then: Describes the differences between digital light processing (DLP), liquid crystal display (LCD), and liquid crystal on silicon (LCoS) Explains how to unwrap phase maps temporally and spatially Shows how to generate fringe patterns with video projectors Demonstrates how to convert phase to coordinates through system calibrations Provides a detailed example of a built-from-scratch 3D imaging system Incorporating valuable insights gained during the author’s 15+ years of 3D imaging research, High-Speed 3D Imaging with Digital Fringe Projection Techniques illuminates the pathway to advancement in high-speed 3D optical imaging using DFP.
Holography 3d Imaging And 3d Display
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Author : Ting-Chung Poon
language : en
Publisher: MDPI
Release Date : 2021-02-19
Holography 3d Imaging And 3d Display written by Ting-Chung Poon and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-02-19 with Technology & Engineering categories.
Modern holographic techniques have been successfully applied in many important areas, such as 3-D inspection, 3-D microscopy, metrology, and profilometry, augmented reality, and industrial informatics. This Special Issue covers selected pieces of cutting-edge research works, ranging from low-level acquisition, to high-level analysis, processing, and manipulation of holographic information. The Special Issue also serves as a comprehensive review of existing state-of-the-art techniques in 3-D imaging and 3-D display, as well as broad insights into the future development of these disciplines. The Special Issue contains 25 papers in the field of holography, 3-D imaging, and 3-D display. All the papers underwent substantial peer review under the guidelines of Applied Sciences.
Development Of A High Speed Robust System For Full Field Of View 3d Shape Measurements
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Author : Michael Jay Zervas
language : en
Publisher:
Release Date : 2011
Development Of A High Speed Robust System For Full Field Of View 3d Shape Measurements written by Michael Jay Zervas and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Abstract: 3D shape measurements are critical in a range of fields, from manufacturing for quality measurements to art conservation for the everlasting archival of ancient sculptures. The most important factor is to gather quantitative 3D information from measurement devices. Currently, there are limitations of existing systems. Many of the techniques are contact methods, proving to be time consuming and invasive to materials. While non-contact methods provide opportunities, many of the current systems are limited in versatility. This project focuses on the development of a fringe projection based system for 3D shape measurements. The critical advantage of the fringe projection optical technique is the ability to provide full field-of-view (FOV) information on the order from several square millimeters to several square meters. In the past, limitations in speed and difficulties achieving sinusoidal projection patterns have restricted the development of this particular type of system and limited its potential applications. For this reason, direct coding techniques have been incorporated to the developed system that modulate the intensity of each pixel to form a sinusoidal pattern using a 624 nm wavelength MEMS based spatial light modulator. Recovered phase data containing shape information is obtained using varying algorithms that range from a single image FFT analysis to a sixteen image, phase stepping algorithm. Reconstruction of 3D information is achievable through several image unwrapping techniques. The first is a spatial unwrapping technique for high speed applications. Additionally, the system uses an optimized Temporal Phase Unwrapping (TPU) algorithm that utilizes varying fringe frequencies ranging from 4 to 512 pixels per fringe to recover shape information in the time domain. This algorithm was chosen based on its robustness and accuracy for high resolution applications [Burke et al., 2002]. Also, unwrapping errors are minimized by approximately 90% as the number of images used is increased from the minimum to maximum fringe density. Contrary to other systems, the 3D shape measurement system developed in the CHSLT laboratories has unprecedented versatility to accommodate a variety of applications with the z-depth resolution of up to 25.4 [mu]m (0.001 inches) and speeds close to 200 frames per second. Hardware systems are integrated into user-friendly software that has been customized for fringe projection. The system has been tested in two extreme environments. The first is for quantification of cracks and potholes in the surface of roads under dynamic conditions. The second application was digitization of an art sculpture under static conditions. The system shows promising results and the potential for high quality images via algorithm optimization. Most importantly, there is potential to present real time 3D information at video speeds.
Image And Graphics
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Author : Yao Zhao
language : en
Publisher: Springer Nature
Release Date : 2019-11-27
Image And Graphics written by Yao Zhao and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-11-27 with Computers categories.
This three-volume set LNCS 11901, 11902, and 11903 constitutes the refereed conference proceedings of the 10thth International Conference on Image and Graphics, ICIG 2019, held in Beijing, China, in August 2019. The 183 full papers presented were selected from 384 submissions and focus on advances of theory, techniques and algorithms as well as innovative technologies of image, video and graphics processing and fostering innovation, entrepreneurship, and networking.