A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

From the Publisher: 
The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

A morphable model for the synthesis of 3D faces

We first provide an overview of 3-D shape measurement us- ing various optical methods. Then we focus on structured light tech- niques where various optical configurations, image acquisition tech- niques, data postprocessing and analysis methods and advantages and limitations are presented. Several industrial application examples are presented. Important areas requiring further R&D are discussed. Finally, a comprehensive bibliography on 3-D shape measurement is included, although it is not intended to be exhaustive. © 2000 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(00)00101-X)

Overview of three-dimensional shape measurement using optical methods

We provide a review of recent advances in 3D surface imaging technologies. We focus particularly on noncontact 3D surface measurement techniques based on structured illumination. The high-speed and high-resolution pattern projection capability offered by the digital light projection technology, together with the recent advances in imaging sensor technologies, may enable new generation systems for 3D surface measurement applications that will provide much better functionality and performance than existing ones in terms of speed, accuracy, resolution, modularization, and ease of use. Performance indexes of 3D imaging system are discussed, and various 3D surface imaging schemes are categorized, illustrated, and compared. Calibration techniques are also discussed, since they play critical roles in achieving the required precision. Numerous applications of 3D surface imaging technologies are discussed with several examples.

Structured-light 3D surface imaging: a tutorial

System calibration, which usually involves complicated and time-consuming procedures, is crucial for any 3-D shape measurement system. In this work, a novel systematic method is proposed for accurate and quick calibration of a 3-D shape measurement system we developed based on a structured light technique. The key concept is to enable the projector to "capture" images like a camera, thus making the calibration of a projector the same as that of a camera. With this new concept, the calibration of structured light systems becomes essentially the same as the calibration of traditional stereovision systems, which is well estab- lished. The calibration method is fast, robust, and accurate. It signifi- cantly simplifies the calibration and recalibration procedures of struc- tured light systems. This work describes the principle of the proposed method and presents some experimental results that demonstrate its performance. © 2006 Society of Photo-Optical Instrumentation Engineers.

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Novel method for structured light system calibration

A high-speed 3-D shape measurement technique based on digital fringe projection has been developed and experimented. This technique uses a computer-generated color fringe pattern whose red, green, and blue channels are sinusoidal fringe patterns with a 120-deg phase shift between neighboring channels. When this color fringe pat- tern is sent to a digital-micromirror-device (DMD) based video projector with no color filter, three gray-scale fringe patterns are repeatedly pro- jected to an object surface in sequence with a cycle time of approxi- mately 10 ms. The three phase-shifted fringe patterns deformed by the object surface are captured by a CCD camera with proper synchroniza- tion between the camera and the projector. The 3-D shape of the object surface is reconstructed by using a phase wrapping and unwrapping algorithm and a phase-coordinate conversion algorithm. Experimental results demonstrated the feasibility of this technique for high-speed 3-D shape measurement with a potential measurement speed up to 100 Hz. © 2003 Society of Photo-Optical Instrumentation Engineers. (DOI: 10.1117/1.1525272) Subject terms: fringe projection; phase shifting; digital micromirror device; 3-D shape measurement.

High-speed 3-D shape measurement based on digital fringe projection

We describe a high-resolution, real-time 3-D shape measurement system based on a digital fringe projection and phase-shifting technique. It utilizes a single-chip digital light processing projector to project computer-generated fringe patterns onto the object, and a high-speed CCD camera synchronized with the projector to acquire the fringe images at a frame rate of 120 frames/s. A color CCD camera is also used to capture images for texture mapping. Based on a three-step phase-shifting technique, each frame of the 3-D shape is reconstructed using three consecutive fringe images. Therefore the 3-D data acquisition speed of the system is 40 frames/s. With this system, together with the fast three-step phase-shifting algorithm and parallel processing software we developed, high-resolution, real-time 3-D shape measurement is realized at a frame rate of up to 40 frames/s and a resolution of 532×500 points per frame.

/pdf/high-resolution-real-time-three-dimensional-shape-2isdwm8ks6.pdf

High-resolution, real-time three-dimensional shape measurement

A color-encoded digital fringe projection technique is proposed for high-speed 3-D surface contouring applications. in this technique, a color fringe pattern whose RGB components comprise three phase-shifted fringe patterns is created by software on a computer screen and then projected to an object by a novel computer-controlled digital projection system. The image of the object is captured by a digital camera positioned at an angle different from that of the projection system. The image is then separated into its RGB components, creating three phase-shifted images of the object. These three images are used to retrieve the 3-D surface contour of the object through the use of a phase wrapping and unwrapping algorithm. Only one image of the object is required to obtain the 3-D surface contour of the object. Thus contouring speed, limited only by the frame rate of the camera, can be dramatically increased as compared to that of the traditional phase-shifting techniques. The technique is especially useful in applications where the object being contoured is going through quasi-static or dynamic changes. The principle of the technique is described and some preliminary experimental results are presented.

Color-encoded digital fringe projection technique for high-speed three-dimensional surface contouring

We propose a new three-step phase-shifting algorithm, which is much faster than the traditional three-step algorithm. We achieve the speed advantage by using a simple intensity ratio function to replace the arctangent function in the traditional algorithm. The phase error caused by this new algorithm is compensated for by use of a look-up-table (LUT). Our experimental results show that both the new algorithm and the traditional algorithm generate similar results, but the new algorithm is 3.4 times faster. By implementing this new algorithm in a high-resolution, real-time 3D shape measurement system, we were able to achieve a measurement speed of 40 frames per second (fps) at a resolution of 532 × 500 pixels, all with an ordinary personal computer.

/pdf/fast-three-step-phase-shifting-algorithm-4gd3op85mi.pdf

Peisen S. Huang

Papers

Novel method for structured light system calibration

High-speed 3-D shape measurement based on digital fringe projection

High-resolution, real-time three-dimensional shape measurement

Color-encoded digital fringe projection technique for high-speed three-dimensional surface contouring

Fast three-step phase-shifting algorithm