scholarly journals Adaptive Fringe Projection for 3D Shape Measurement with Large Reflectivity Variations by Using Image Fusion and Predicted Search

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Wei Feng ◽  
Shaojing Tang ◽  
Xiaodong Zhao ◽  
Guodong Sun ◽  
Daxing Zhao
Keyword(s):  
Image Fusion ◽  
Search Algorithm ◽  
Specular Reflection ◽  
Structured Light ◽  
Fringe Projection ◽  
Hardware Complexity ◽  
Digital Fringe Projection ◽  
Optimal Projection ◽  
Phase Calculation ◽  
Unsaturated Condition

There is always a great challenge for the structured light technique that it is difficult to deal with the surface with large reflectivity variations or specular reflection. This paper proposes a flexible and adaptive digital fringe projection method based on image fusion and interpolated prediction search algorithm. The multiple mask images are fused to obtain the required saturation threshold, and the interpolated prediction search algorithm is used to calculate the optimal projection gray-level intensity. Then, the projection intensity is reduced to achieve coordinate matching in the unsaturated condition, and the adaptive digital fringes with the optimal projection intensity are subsequently projected for phase calculation by using the heterodyne multifrequency phase-shifted method. The experiments demonstrate that the proposed method is effective for measuring the high-reflective surface and unwrapping the phase in the local overexposure region completely. Compared with the traditional structured light measurement methods, our method can decrease the number of projected and captured images with higher modulation and better contrast. In addition, the measurement process only needs two prior steps and avoids hardware complexity, which is more convenient to apply to the industry.

A New Three-Dimensional Profilometer for Surface Profile Measurement Using Digital Fringe Projection and Phase Shifting

2005 ◽  
Vol 295-296 ◽  
pp. 471-476
Author(s):  
Liang Chia Chen ◽  
S.H. Tsai ◽  
Kuang Chao Fan
Keyword(s):  
High Speed ◽  
Structured Light ◽  
Three Dimensional ◽  
Surface Profile ◽  
Phase Shifting ◽  
Fringe Projection ◽  
Surface Measurement ◽  
Profile Measurement ◽  
Digital Fringe Projection ◽  
Fringe Patterns

The development of a three-dimensional surface profilometer using digital fringe projection technology and phase-shifting principle is presented. Accurate and high-speed three-dimensional profile measurement plays a key role in determining the success of process automation and productivity. By integrating a digital micromirror device (DMD) with the developed system, exclusive advantages in projecting flexible and accurate structured-light patterns onto the object surface to be measured can be obtained. Furthermore, the developed system consists of a specially designed micro-projecting optical unit for generating flexibly optimal structured-light to accommodate requirements in terms of measurement range and resolution. Its wide angle image detection design also improves measurement resolution for detecting deformed fringe patterns. This resolves the problem in capturing effective deformed fringe patterns for phase shifting, especially when a coaxial optical layout of a stereomicroscope is employed. Experimental results verified that the maximum error was within a reasonable range of the measured depth. The developed system and the method can provide a useful and effective tool for 3D full field surface measurement ranging from µm up to cm scale.

Dynamics range enhancement in digital fringe projection technique

2015 ◽  
Vol 39 ◽  
pp. 243-251 ◽  
Author(s):  
Gelareh Babaie ◽  
Mehrdad Abolbashari ◽  
Faramarz Farahi
Keyword(s):  
Fringe Projection ◽  
Projection Technique ◽  
Digital Fringe Projection

scholarly journals Adaptive Binocular Fringe Dynamic Projection Method for High Dynamic Range Measurement

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4023 ◽  
Author(s):  
Changzhi Yu ◽  
Fang Ji ◽  
Junpeng Xue ◽  
Yajun Wang
Keyword(s):  
Projection Method ◽  
Dynamic Range ◽  
Three Dimensional ◽  
High Dynamic Range ◽  
Fringe Projection ◽  
Range Measurement ◽  
Optimal Projection ◽  
Three Dimensional Measurement ◽  
High Dynamic ◽  
Adaptively Adjusting

Three-dimensional measurement with fringe projection sensor has been commonly researched. However, the measurement accuracy and efficiency of most fringe projection sensors are still seriously affected by image saturation and the non-linear effects of the projector. In order to solve the challenge, in conjunction with the advantages of stereo vision technology and fringe projection technology, an adaptive binocular fringe dynamic projection method is proposed. The proposed method can avoid image saturation by adaptively adjusting the projection intensity. Firstly, the flowchart of the proposed method is explained. Then, an adaptive optimal projection intensity method based on multi-threshold segmentation is introduced to adjust the projection illumination. Finally, the mapping relationship of binocular saturation point and projection point is established by binocular transformation and left camera–projector mapping. Experiments demonstrate that the proposed method can achieve higher accuracy for high dynamic range measurement.

Algorithms for Generating Adaptive Projection Patterns for 3-D Shape Measurement

2007 ◽  
Author(s):  
Tao Peng ◽  
Satyandra K. Gupta
Keyword(s):  
Point Cloud ◽  
Measurement Accuracy ◽  
Point Clouds ◽  
Fringe Projection ◽  
Shape Measurement ◽  
Digital Fringe Projection ◽  
Physical Experiments ◽  
Dense Point ◽  
Improved Performance ◽  
Fringe Patterns

Point cloud acquisition using digital fringe projection (PCCDFP) is a non-contact technique for acquiring dense point clouds to represent the 3-D shapes of objects. Most existing PCCDFP systems use projection patterns consisting of straight fringes with fixed fringe pitches. In certain situations, such patterns do not give the best results. In our earlier work, we have shown that in some situations, patterns that use curved fringes with spatial pitch variation can significantly improve the process of constructing point clouds. This paper describes algorithms for automatically generating adaptive projection patterns that use curved fringes with spatial pitch variation to provide improved results for an object being measured. In addition, we also describe the supporting algorithms that are needed for utilizing adaptive projection patterns. Both simulation and physical experiments show that, adaptive patterns are able to achieve improved performance, in terms of measurement accuracy and coverage, than fixed-pitch straight fringe patterns.

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