Three-Dimensional Inner Surface Inspection System Based on Circle-Structured Light

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Zhu Ye ◽  
Wang Lianpo ◽  
Gu Yonggang ◽  
Bi Songlin ◽  
Zhai Chao ◽  
...  
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Absolute Error ◽  
Surface Measurement ◽  
Laser Triangulation ◽  
Inspection System ◽  
Surface Inspection ◽  
Laser Plane ◽  
Inner Surface

A three-dimensional (3D) inner surface inspection system is developed in this research based on circle-structured light, which is an improved laser triangulation method. A conical reflector is used to reflect the laser and generate radial laser plane that is called circle-structured light, and a CCD camera is used to capture the light stripe on the inner surface. Then, the 3D coordinates of points on the light stripe are calculated through laser triangulation algorithm. Compared with existing inner surface measurement systems, this research takes assembly errors and refraction distortion into consideration and proposes a laser plane mathematical model with four degrees-of-freedom along with corresponding flexible laser plane calibration technique based on binocular vision that is easy to operate. The proposed inspection system calibrated by proposed algorithm performs well in diameter measurement experiment, in which the absolute error is superior to 3 μm, and defect detecting experiment, in which the defect resolution is superior to 0.02 mm. Moreover, the system also performs well in straightness and roundness evaluation. Experiments indicate that this system is applicable in inner surface measurement and inspection, and the calibration method is accurate and easy to operate.

A Laser Triangulation-Based 3D Measurement System for Inner Surface of Deep Holes

2018 ◽  
Author(s):  
Zhu Ye ◽  
Wang Lianpo ◽  
Yonggang Gu ◽  
Zhai Chao ◽  
Baoyang Jiang ◽  
...  
Keyword(s):  
Measurement System ◽  
Absolute Error ◽  
Surface Measurement ◽  
Laser Triangulation ◽  
Inspection System ◽  
Maximum Absolute Error ◽  
Measurement Systems ◽  
Laser Plane ◽  
Inner Surface ◽  
3D Measurement System

Basing on the laser-triangulation principle, a deep hole inner surface inspection system is developed in this research. Compared with existing inner surface measurement systems, this research takes assembly errors and refraction distortion into consideration and proposes a flexible laser plane calibration technique based on binocular vision that is easy to operate. The measurement system calibrated by proposed method performs well in the field test in which the maximum absolute error of the measured ring gauge diameter is 3μm. Experiment indicates that this system is accurate and suitable for inner surface measurement. Point cloud registration may be applied in the future to extend the system’s applicability.

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.

Structured-Light Based Rapid 3D Measurement of Plant Canopy Structure

2014 ◽  
Vol 701-702 ◽  
pp. 549-553 ◽  
Author(s):  
Zhe Chen ◽  
Xu Dong Li ◽  
Shao Guang Shi ◽  
Hong Zhi Jiang ◽  
Hui Jie Zhao
Keyword(s):  
Data Collection ◽  
Structure Data ◽  
Measurement System ◽  
Structured Light ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Plant Canopy ◽  
Laser Stripe ◽  
3D Data

Density three dimensional plant canopy structure data has numerous applications in agriculture, but many existing 3D data collection approaches are time-consuming. In this paper, we present a measurement system based on structured-light for plant canopy structure data collection. The structured-light projector projects laser beam reflected by dual-oscillating mirror, arrives to the plant canopy, which is captured by a camera. We propose a new scanning mode, that is, during one exposure time of CCD camera, one mirror keeps moving in high frequency and small angle, while the other one maintains the same position, so that we can get a laser stripe rather than a spot in each image, from which about 100 sub-pixel centers of laser stripe can be extracted. Experiments show that the measurement system can rapid collect three dimensional information of the plant.

scholarly journals Rail wear inspection based on computer-aided design model and point cloud data

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881678 ◽  
Author(s):  
Peng Chen ◽  
Yong Hu ◽  
Wen-Tao Li ◽  
Pei-Jun Wang
Keyword(s):  
Computer Aided Design ◽  
Point Cloud ◽  
Structured Light ◽  
Three Dimensional ◽  
Point Clouds ◽  
Design Model ◽  
Inspection System ◽  
Rail Wear ◽  
Computer Aided ◽  
Aided Design

Railway transportation demands more efficient and accurate rail wear inspection systems to ensure the train operation safety. To obtain continuous three-dimensional data, a structured light rail wear inspection system is developed in this article, and the data processing method for aligning the point cloud from structured light scanning to the nominal computer-aided design model of the rail is investigated. For further data registration, the point cloud of the computer-aided design model is generated and the normal vectors of these points are calculated. In the coarse registration, conformal geometric algebra is applied to align the segmented point clouds by intuitive geometric calculations to those from the computer-aided design model. In the fine registration, the accurate alignment of the point clouds is implemented by the iterative closest point algorithm. The vertical and lateral wear amounts are obtained on the cross section by slicing the aligned three-dimensional point clouds data. Finally, the proposed system and method are validated by comparing the vertical wear amounts with the two-dimensional laser scanning and contact measurement results.

The Measurement of Three-Dimensional Road Roughness Based on Laser Triangulation

2011 ◽  
Vol 346 ◽  
pp. 812-816 ◽  
Author(s):  
Xiao Qin Li ◽  
Zhi Xiong Lu ◽  
Lan Ying Zhao ◽  
Zheng Hao Li ◽  
Bing Guo ◽  
...  
Keyword(s):  
Measurement Method ◽  
Three Dimensional ◽  
Measurement Range ◽  
Surface Measurement ◽  
Laser Triangulation ◽  
Roughness Measurement ◽  
Ccd Imaging ◽  
Road Roughness ◽  
Dimensional Surface ◽  
Standard Range

This article did some non-contact measurement by laser triangulation principle on the A level hard road roughness, based on CCD imaging principle,used scanning galvanometer, which improved the measurement speed and surface measurement range, , drew the three-dimensional surface roughness profile curve by interpolation and fitting,It was in accordance with the standard range of A-road height spectrum. This measurement method have important guiding significance on the hard road roughness measurement and practice of the design of the relatively flat three-dimensional contours.

Study on Stereo Vision for 3D Reconstruction of Welding Seam

2013 ◽  
Vol 850-851 ◽  
pp. 212-216 ◽  
Author(s):  
Jun Du ◽  
Ling Yu Yong ◽  
Mei Sun ◽  
Jia Sheng Ge
Keyword(s):  
Stereo Vision ◽  
Vision System ◽  
Structured Light ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Detection Accuracy ◽  
Matching Problem ◽  
Welding Seam ◽  
Algorithm Performance ◽  
Three Dimensional Coordinate

The Monocular stereo vision sensor based on structured light is designed and invented for the detection of the weld seam. By incorporating the structured light, the corresponding points matching problem in the stereo vision has been solved effectively. Firstly, the built monocular stereo vision system is used to obtain the image information of seam surface. Then the image coordinate of the seam feature points in the two-dimensional plane can be identified and extracted, through the responding image processing and feature analysis of the seam image collected. After that, the three-dimensional coordinates are calculated by using the theory of projective geometry according to the positional relation between the CCD camera and structured light projected in the seam surface. By this way, the seam feature information such as the three-dimensional geometry sizes, the groove type, the angle, and the interval can be obtained. Finally, the algorithm performance is tested by the experiment of obtaining the three-dimensional coordinate for seams center points, and the results have proved the detection accuracy and reliability of the visual collection system.

Design of an oil pipe inner surface inspection system

2011 ◽  
Author(s):  
Abdellatif Bouchalkha ◽  
Mohammed Sabri Hamad ◽  
Khaled Al-Beloushi ◽  
Mana Al-Qayedi ◽  
Khalid Al-Hammadi
Keyword(s):  
Inspection System ◽  
Surface Inspection ◽  
Inner Surface

High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

1994 ◽  
Vol 52 ◽  
pp. 218-219
Author(s):  
Robert W. Mackin
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Ccd Camera ◽  
Objective Lens ◽  
Array Processor ◽  
Vaginal Smears ◽  
Low Contrast ◽  
Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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