In this work, a model based method is applied to phase measuring deflectometry, named modal deflectometry. The height and slopes of the surface under test are represented by mathematical models updated optimizing coefficients minimize discrepancy between reprojection in ray tracing actual measurement. pose screen relative camera pre-calibrated further optimized together with shape test. Simulations experiments conducted demonstrate feasibility proposed approach.

There are wide applications for zonal reconstruction methods in slope-based metrology due to its good capability of reconstructing the local details on surface profile. It was noticed literature that large errors occur when using designed rectangular geometry process slopes a quadrilateral geometry, which is more general with phase measuring deflectometry. In this work, we present new idea geometry. Instead employing intermediate set up height-slope equations, consider height increment as...

Structured light 3D shape metrology has become a very important technique and one of the hot research topics in face recognition. However, it is still challenging to use digital projector (DLP) scanner achieve high-speed, low-cost, small-size, infrared-illuminated measurements. Instead using DLP, this paper proposes galvanometer project phase-shifted fringes with projection speed infrared up 500 fps. Moreover, measurement accuracy multi-frequency (hierarchical) multi-wavelength (heterodyne)...

In this Letter, the periodical errors, which are caused by nonlinear effect of commercial projector and camera, analyzed as a more generic single-coefficient model. The probability density function wrapped phase distributions is used tool to find compensation coefficient. When coefficient detected, on premise ensuring accuracy, correlation algorithm process replace traditional iterative process. Therefore, proposed improves efficiency detection dramatically. Both computer simulation...

This paper presents a method for camera calibration based on the orthogonal vanishing point using concentric circles grating and wedge grating. method, which we believe is new, uses high-precision characteristics of phase extraction to obtain feature points, thus decreasing errors caused by traditional marker gray pattern. According simulation experiment analysis results, was designed with seven periods four periods. In real measuring experiment, target similar were used calibrate camera,...

In this work, we proposed for stitching interferometry to use a triple-beam interferometer measure both the distance and tilt all sub-apertures before process. The relative piston between two neighboring is then calculated by using data in overlapping area. Comparisons are made our method, classical least-squares principle method. Our method can improve accuracy repeatability of when large number sub-aperture topographies taken into account. simulations experiments on flat spherical mirrors...

Three-dimensional measurement with fringe projection sensor has been commonly researched. However, the accuracy and efficiency of most sensors are still seriously affected by image saturation non-linear effects projector. In order to solve challenge, in conjunction advantages stereo vision technology technology, an adaptive binocular dynamic method is proposed. The proposed can avoid adaptively adjusting intensity. Firstly, flowchart explained. Then, optimal intensity based on...

In this work, we present one-dimensional stitching interferometry based on the angular measurement for high-precision mirror metrology. The tilt error introduced by stage motion during process is measured an extra device. local profile interferometer in a single field of view corrected using angle before piston adjustment process. Comparing to classical software technique, measuring technique more reliable and accurate profiling surface at nanometer level. Experimental results demonstrate...

The correspondence residuals due to the discrepancy between reality and shape model in use are analyzed for modal phase measuring deflectometry. Slope calculated from these discrepancies estimation practical acquisition. Since mismatch mainly occurs locally, zonal integration methods which good at dealing with local variations used reconstruct height residual compensation. Results of both simulation experiment indicate proposed compensation method is effective, can be as a post-complement

Benefiting from the characteristics of full field scanning, high resolution and precision, digital fringe projection measurement technology has been widely used in three-dimensional measurement. For cylinder pose detection, due to influence occlusion noise, obtained point cloud information is usually incomplete, resulting unreliable object parameters after fitting. In view above problems, a fitting method with incomplete data based on cutting plane proposed. Firstly, processed by bilateral...

Binocular structured light systems are widely used in 3D measurements. In the condition of complex and local highly reflective scenes, to obtain more information, binocular usually divided into two pairs devices, each having a Single Camera Projector (SCP). this case, system can be seen as Dual Cameras-Projector (DCP) system. DCP calibration, Left-SCP Right-SCP need calibrated separately, which leads inconsistent parameters for same projector, thus reducing measurement accuracy. To solve...

The accuracy of phase demodulation has significant impact on the fringe projection 3D measurement. Currently, researches based deep learning methods for extracting wrapped mostly use U-Net as subject network. connection method between its hierarchies certain shortcomings in global information transmission, which hinders improvement prediction accuracy. We propose a single-shot novel full-scale network SE-FSCNet. encoder and decoder SE-FSCNet have same number but are not completely...

The rotational speed vectors of the bearing balls affect their service life and running performance. Observing actual ball is a prerequisite for revealing its true motion law conducting sliding behavior simulation analysis. To address need accuracy real-time measurement spin angular velocity, which also under high-frequency high-speed conditions, new method rotation based on binocular vision system proposed. Firstly, marker points are laid balls, three-dimensional (3D) coordinates in camera...

Commonly, fringe-projection photogrammetry involves two independent stages: system calibration and measurement. The measurement accuracy largely depends on the procedure. However, results of may be unstable in different occasions. In this Letter, we propose a robust self-calibration 3D shape by combining control points. points with known coordinates are provided checkerboard, identified absolute phase information deformed fringes. introduction nonlinear collinearity equations can regarded as...

This paper considers the three-dimensional (3D) shape measurement of metal parts during an additive manufacturing process in a direct energy deposition (DED) printing system with high temperature and strong light; binocular based on ultraviolet light source projection is built using fringe Fourier analysis. Firstly, optical filter are used to obtain high-quality patterns environment thermal radiation. Then, analysis carried out by single deformed fringe, spatial phase unwrapping algorithm...

The paper deals with the process tolerance allocation problem for manufacturing a product angular features in two-dimensional charting. First, discrete interval cost–tolerance model is investigated to represent relationship between cost and tolerance. Then multichoice knapsack formulated allocate systematically best each individual machining dimension both radial axial directions objective of minimizing total cost. Furthermore, genetic algorithm developed obtain optimal solution model....

The X-ray deformable mirror (XDM) is becoming widely used in the present synchrotron/free-electron laser facilities because of its flexibility correcting wavefront errors or modification beam size at sample location. Owing to coupling among N actuators an XDM, ( + 1) (2 scans are required learn response each actuator one by one. When has important number ) and time including stabilization necessary metrology long, learning process can be consuming. In this work, a fast accurate method...

Phase Measuring Deflectometry (PMD) is a powerful tool to measure the three-dimensional shape for freeform specular surfaces. In this work, model based method applied PMD, called as Modal (MPMD). The surface height and slopes are represented in mathematical models updated by optimizing coefficients, order minimize discrepancy between reprojection ray tracing actual measurement. pose of screen relative camera pre-calibrated then optimized together with coefficients. Moreover, correspondence...

Traditional filtering methods only focused on improving the peak signal-to-noise ratio of single fringe pattern, which ignore effect phase extraction. Fringe phase-shifting field based fuzzy quotient space-oriented partial differential equations method is proposed to reduce error caused by Gaussian noise while filtering. First, distribution that analyzed. Furthermore, introducing and theory space, modified direction can be adaptively obtained, transforms traditional image into multi-image...

Ellipse center extraction is the important basis of camera calibration with circle arrays board, which directly affects measurement accuracy machine vision system. Aiming at problem high noise sensitivity most ellipse methods, a robust multi-ellipse method proposed. The idea to transform into problems sub-pixel edge segmentation and based clustering. Firstly, flowchart proposed introduced. Then, theory fuzzy quotient space introduced establish dynamic granularity matrix model, describes...

Synchrotron Radiation Workshop (SRW) is a powerful synchrotron radiation simulation tool and has been widely used at facilities all over the world. During last decade, many types of X-ray wavefront sensors have developed used. In this work, we present our recent effort on development at-wavelength metrology based SRW mainly focused Hartmann Wavefront Sensor (HWS). Various conditions studied to verify that simulated HWS performing as expected in terms accuracy. This then align KB mirrors by...