画像技術を用いた陶磁器の形状計測・下絵描画システム

Despite the availability of various Process Analytical Technologies (PAT) for measuring other particle properties, their inherit limitations for the measurement of crystal shape have been restricted. This has impacted, in turn, on the development and implementation of optimisation, monitoring and control of crystal shape and size distributions within particle formulation and processing systems In recent years, imaging systems have shown to be a very promising PAT technique for the measurement of crystal growth, but still essentially limited as a technique only to provide two-dimensional information. The idea of using two synchronized cameras to obtain 3D crystal shape was mentioned previously (Chem Eng Sci 63(5) 1171–1184, 2008) but no quantitative results were reported. In this paper, a methodology which can directly image the full three-dimensional shape of crystals has been developed. It is based on the mathematical principle that if the two-dimensional images of an object are obtained from two different angles, the full three-dimensional crystal shape can be reconstructed. A proof of concept study has been carried out to demonstrate the potentials in using the system for the three-dimensional measurement of crystals.

Nano-level 3-D measurement is one of the key technologies for the current and next generation of production systems for semi-conductors, LCDs and nano-devices. To meet with these applications, “Wide range nano-level 3-D shape measurement method using combination of RGB laser lights” has been developed. It measures the height of nano-objects from the combination of RGB LED lights combinations. To analyze the combination of RGB lights, the color analysis method on xy-color plane has been introduced. In this method, the color changes on xy-color plane means the height changes. Experimental system to measure the micro-meter heights using RGB lightings has been developed, and succeeded to measure the 50 nm step and 500 nm step samples.

Confocal 3-D imaging technique is a newly developed technique and widely used in many fields of research and development. It is to utilize light intensity sensitive measuring technique. Confocal 3-D profile measurement system is widely used in high resolution inspection. For high precision 3-D imaging inspection in confocal measuring system, light source acts a very important role in system resolution and accuracy. In order to improve measuring repeatability and stability, to reduce measurement error, and to lower the light source stability requirement and cost, this paper studied light source fluctuation effect to confocal imaging measurement; deduced depth response model function; analyzed system error caused by light source fluctuation; and presented a new scheme to reduce the affection of light source fluctuation. Theoretical analysis and experiment result verified that light source fluctuation should be considered and eliminated in very high resolution confocal 3-D shape measurement system.

This paper presents a patented three-dimensional (3D) shape measurement system, ReCreator, which is mainly composed of two CCD cameras and a random pattern projector with fixed geometry. It can work in the binocular mode, where the stereo image pair is utilized to reconstruct the 3D point cloud in the common field of view of the two cameras; while in the monocular mode, each single camera and the random pattern projector constitute a measuring unit respectively to alleviate the highlight and occlusion effect. The design and the calibration of the random pattern projector, which is the key ingredient for enabling the system, are discussed in detail. The system algorithms are partially implemented with NVIDIA Graphics Processing Units (GPU) in the Compute Unified Device Architecture (CUDA) programming environment, which proves effective to accelerate the computation. Experiments are conducted to validate the precision, rapidity and data integrity of the measurement system.

Visualization of 3D variable in time object based on data gathered by active measurement system

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 established. The calibration method is fast, robust, and accurate. It significantly simplifies the calibration and recalibration procedures of structured light systems. This work describes the principle of the proposed method and presents some experimental results that demonstrate its performance.

We present a system for 360-deg shape measurement based on three-dimensional (3-D) orientation target. The measurement system mainly includes a CCD camera, digital light projector, 3-D orientation target, and the measured object. The global coordinates for all chessboard corners of the target are calculated based on close-range photogrammetry, for which the relative orientation between camera stations is discussed in detail. According to the homography matrix between the checkerboard and its image plane, the position and orientation of the measuring camera relative to the target are determined. A dot-matrix structured light is designed and projected onto the measured object surface. In each image of the structured light deformed by the object shape, the pixel coordinates of the dot-centers are accurately calculated by the ellipse-fitting algorithm, and then they are all sorted in the same order by the beads-stringing matching method. In the experiment, the designated front, rear, left, and right surfaces of a reference object are measured, and their separate point clouds are automatically stitched together by the 3-D orientation target. Compared with coordinate measurement machine data, the accuracy of the system is demonstrated; the maximum deviations are +1.257 / − 0.977 mm, and the standard deviation is 0.124 mm.

Support System for 3D Shape Measurement of Relics

Research and application on shape meter are introduced, especially in China. A self-made MPIBPST (multi-roll-piece inner bore piezomagnetic sensor type) shape meter roll for cold-rolled steel strip was applied in to the industrial test. MPIBPST means that one shape meter roll is made up of some roll-picesce, there are two bores in each roll picesce, and each inner bore contains one piezomagnetic sensor. In order to combine with the work of the shape meter roll and display the real-time shape, a shape measurement system based on TMS320F2812 is designed and developed. Measurement principle on shape, hardware and software design are described in detail. The running in the industrial field for about six months shows that shape meter has the advantages of signal stability and credibility, stronger anti-interference ability, high-precision, and meets the measuring requirements on the industrial field. The successful application of the MPIBPST shape meter lays a solid foundation for the further research on AFC (Automatic Flatness Control System) in China. The design on this system also has a reference value for similar work.

In this paper, we discuss the performance of a 3-D shape measurement system in aim of applying the system for improving the cosmesis of the prosthetic hand gloves and covers. The human hand shape is a complex continued closed shell that requires multi dimensional shots to be united for reproducing precise full surface model in 3-D CG and CAD software. The building process requires visual observation of the model and manual operation, which involves skill, to create high precision model in limited time. This paper reports the experimental consideration of the effect of marker properties (color, thickness, background color) that upsets the surface configuration. The characteristic and evaluation method of the deformation and the experimental results are shown.

Non-sinusoidal phase error is common in structured light three-dimensional (3D) shape measurement system, thus we perform theoretical and experimental analyses of such error. The number of non-sinusoidal waveform errors in a 2\pi phase period is the same as the number of steps of the phase-shifting algorithm; no errors occur within the one-phase period. Based on our findings, a new structured light method, the linear sinusoidal phase-shifting method (LSPS), that is resistant to non-sinusoidal phase error is proposed. Experiments show that the non-sinusoidal waveform error is reduced to an almost negligible level (0.001 rad) using the proposed LSPS.

System calibration is crucial for any 3-D shape measurement system. An accurate method is proposed to calibrate a 3-D shape measurement system based on a structured light technique. The projector is treated as a camera to unify the calibration procedures of a structured light system and a well-established stereo vision system. The key to realizing this method is to establish a highly accurate correspondence between camera pixels and projector pixels and generate digital micromirror device (DMD) image sets for projector calibration. A phase-shifting method is used to accomplish this task. A precalibrated lookup table and a linear interpolation algorithm are proposed to improve the accuracy of the generated DMD image, and accordingly improve the accuracy of the projector calibration and the 3-D measurement. Some experimental results are presented to demonstrate the performance of the system calibration.

3-D shape measurement systems by contactless method are required in the quality inspections of metal molds and electronic parts in industrial fields. A grating projection method with phase-shifting method has advantages of high precision and high speed. Recently, the size of a BGA (ball grid array) becomes smaller. So the pitch of a grating pattern projected onto the specimen should be smaller. In conventional method, fringe pattern is projected using an imaging lens. The focal depth becomes smaller in the case of reduced projection. It is therefore difficult to project a grating pattern with small pitch onto an object with large incident angles. Authors recently proposed a light source stepping method using a linear LED device. It is easy to shrink the projected grating pitch with a lens because this projection method does not use an imaging lens. The pitch of the projected grating depends on the width of the light source. There is a limit to shrink the projected grating pitch according to the size of the LED chip. In this paper, a small pitch fringe projection method with multiple linear fiber arrays for 3D shape measurement is proposed. The width of the fiber array is 30μm. It is one digit smaller than the width of the LED chip. The experimental result of 3-D shape measurement with small pitch projection with large incident angles is shown.

A method for measuring 3-D objects with surfaces composed of various reflective regions is developed in which the 3-D coordinates of the object sections are obtained by triangulation with the light-section method by using a slit-light source and a TV camera. A slit-light source in which the lighting intensity is controllable and a TV camera with an expanded dynamic range are employed to reduce the influence of uneven reflective surfaces. The TV camera expands its dynamic range by combining multiple images captured at different shutter speeds. A trial 3-D shape measurement system is produced using this method, and its effectiveness is confirmed by experiments.

Three-dimensional (3D) shape measurement system with binary defocusing technique can perform high-speed and flexible measurements if binary fringe patterns are defocused by projector properly. However, the actual defocusing degree is difficult to set, and the fringe period is difficult to determine accordingly. In this study, we present a square-binary defocusing parameter selection framework. First, we analyze the fringe formation process mathematically. The defocusing degree is quantified and manipulated by using the focusing distance of projector, which is calibrated by point spread function measurement. To optimize parameter selection, single-point sinusoidal error is modeled as the objective function for the evaluation of the defocusing effect. We verify the correctness by using different parameter combinations and object measurements in our experiments. The appropriate defocusing parameters can be easily obtained according to the analysis of practical system setup, which improves the quality and robustness of the system.