Specular surface measurement by using a moving diffusive structured light source

2007 ◽  
Author(s):  
Hongwei Guo ◽  
Tao Tao
Keyword(s):  
Light Source ◽  
Structured Light ◽  
Surface Measurement ◽  
Specular Surface

Calibration of Endoscopic Systems Coupled to a Camera and a Structured Light Source

MAPAN ◽  
2018 ◽  
Vol 34 (2) ◽  
pp. 143-157 ◽  
Author(s):  
Octavio Icasio-Hernández ◽  
Juan B. Hurtado-Ramos ◽  
José-Joel Gonzalez-Barbosa
Keyword(s):  
Light Source ◽  
Structured Light

scholarly journals Accurate and Robust Surface Measurement Using Optimal Structured Light Tracking Method

2010 ◽  
Vol E93-D (2) ◽  
pp. 293-299 ◽  
Author(s):  
Shi WANG ◽  
Hyongsuk KIM ◽  
Chun-Shin LIN ◽  
Hongxin CHEN
Keyword(s):  
Structured Light ◽  
Surface Measurement ◽  
Tracking Method

3D Imaging for Nondestructive Testing

NDT World ◽  
2019 ◽  
pp. 30-34
Author(s):  
Мэтт Беллис ◽  
Matt Bellis
Keyword(s):  
Nondestructive Testing ◽  
Optical Imaging ◽  
Light Source ◽  
3D Imaging ◽  
Structured Light ◽  
Maximum Amount ◽  
Metal Loss ◽  
Imaging Technologies ◽  
Line Scanning ◽  
River Bottom

The article focuses on two 3D optical imaging technologies and the application of these technologies to nondestructive testing: laser line scanning and structured light. Both technologies determine depth based on triangulation between a light source, the object under inspection, and a camera sensor. Both technologies have demonstrated accuracy, precision, and probabilities of detection sufficient to meet the demands of nondestructive testing. The second part of the article focuses on the application of 3D imaging in the assessment of corrosion on pipelines. In this application, 3D imaging is used to identify areas of corrosion, determine the maximum amount of metal loss, extract the river bottom profile, and calculate the remaining strength of a pipeline.

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.

Improved system calibration for specular surface measurement by using reflections from a plane mirror

2016 ◽  
Vol 55 (25) ◽  
pp. 7018 ◽  
Author(s):  
Tian Zhou ◽  
Kun Chen ◽  
Haoyun Wei ◽  
Yan Li
Keyword(s):  
Surface Measurement ◽  
Plane Mirror ◽  
System Calibration ◽  
Specular Surface

scholarly journals STRUCTURED LIGHT BASED 3D SCANNING FOR SPECULAR SURFACE BY THE COMBINATION OF GRAY CODE AND PHASE SHIFTING

2016 ◽  
Vol XLI-B3 ◽  
pp. 137-142
Author(s):  
Yujia Zhang ◽  
Alper Yilmaz
Keyword(s):  
High Frequency ◽  
Structured Light ◽  
Gray Code ◽  
3D Scanning ◽  
Phase Shifting ◽  
Scanning System ◽  
High Quality ◽  
Specular Surface ◽  
Combination Technique ◽  
Indirect Illumination

Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new combined coding method.

Influence of Coating Spray on Surface Measurement Using 3D Optical Scanning Systems

2019 ◽  
Author(s):  
Yuhang Yang ◽  
Siyuan Chen ◽  
Letao Wang ◽  
Jingying He ◽  
Shang-Ming Wang ◽  
...  
Keyword(s):  
Structured Light ◽  
Spray Coating ◽  
Surface Measurement ◽  
Scanning System ◽  
3D Measurement ◽  
Optical Scanning ◽  
Wide Range ◽  
Structured Light Scanning ◽  
3D Measurement System ◽  
Scanning Systems

Abstract High-resolution 3D measurement is crucial for a wide range of applications in manufacturing. With the recent development of optical technologies, the performance of many 3D scanning systems has entered the practical range for object digitizing, reverse engineering, quality control, and many other manufacturing applications. In order to extend the measurement capability to reflective or transparent surfaces, a common practice for reducing the unwanted reflection and refraction is to coat the surfaces with micro-particle spray. There is, however, limited discussion about the influence of coating spray on the resulted measurement precision of 3D optical scanning systems, and due to lack of standardized procedure for spray coating, the variability caused by different operators in surface measurement remains to be examined. This paper investigates the 3D data acquisition of spray-coated surfaces with a structured-light scanning system through experiments and statistical analysis. Both surface roughness and spatial statistics are used to quantitatively evaluate the characteristics of the 3D measurement system. Gauge R&R study is conducted to determine measurement repeatability and reproducibility. The results demonstrate that both the number of spray pass and the skill of the individual operator can significantly affect the performance of the structured-light scanning system. Other pertinent suggestions for the operation of 3D optical scanning systems with spray coating are also provided.

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