Combined non-contact coordinate measurement system and calibration method

2015 ◽  
Vol 70 ◽  
pp. 100-105 ◽  
Author(s):  
Yiyan Fan ◽  
Bin Zhao
2017 ◽  
Vol 870 ◽  
pp. 147-152
Author(s):  
Ling Hui Yang ◽  
Li Jun Wang ◽  
Hai Qing Liu ◽  
Yong Jie Ren ◽  
Jia Rui Lin ◽  
...  

This paper presents a high-resolution real-time 3D coordinate measurement system based on multi-angle intersection and cylindrical imaging. The measuring angle is detected by the linear camera equipped with cylindrical lenses, whose field of view is a 3D space rather than 2D plane. This camera has prominent advantages in precise coordinate measurement and dynamic position tracking due to the high resolution and outstanding frame rate of linear CCD. Each camera is a 1D angle measuring unit which confirms an angle thereby a plane passing through the light spot. With three cameras arrangement in front of the measurement field, the 3D coordinate of the light spot can be reconstructed by multi-angle intersection. An accurate and generic calibration method is introduced to calibrate this camera. The proposed calibration method is based on nonparametric ideas to find the mapping from incoming scene rays to photo-sensitive elements, and this method (black box calibration) is still effective even if the lens distortion is high and asymmetric. It is applicable to a central (single viewpoint) camera equipped with any lenses. The proposed calibration method is applied to the 3D coordinate measurement system. The coordinate measurement accuracy of the designed system is better than 0.49mm.


Author(s):  
Dongri Shan ◽  
Chenglong Zhang ◽  
Peng Zhang ◽  
Xiaofang Wang ◽  
Dongmei He ◽  
...  

Light pen 3D vision coordinate measurement systems are increasingly widely used due to their advantages, such as small size, convenient carrying and wide applicability. The posture of the light pen is an important factor affecting accuracy. The pose domain of the pen needs to be given so that the measurement system has a suitable measurement range to obtain more qualified parameters. The advantage of the self-calibration method is that the entire self-calibration process can be completed at the measurement site without any auxiliary equipment. After the system camera calibration is completed, we take several pictures of the same measurement point with different poses to obtain the conversion matrix of the picture, and then use spherical fitting, the generalized inverse method of least squares, and the principle of position invariance within the pose domain range. The combined stylus tip center self-calibration method calculates the actual position of the light pen probe. The experimental results show that the absolute error is stable below 0.0737 mm and that the relative error is stable below 0.0025 mm. The experimental results verify the effectiveness of the method; the measurement accuracy of the system can meet the basic industrial measurement requirements.


2011 ◽  
Vol 19 (4) ◽  
pp. 870-877 ◽  
Author(s):  
劳达宝 LAO Da-bao ◽  
杨学友 YANG Xue-you ◽  
邾继贵 ZHU Ji-gui ◽  
叶声华 YE Sheng-hua

2014 ◽  
Vol 989-994 ◽  
pp. 3266-3269
Author(s):  
Zi Miao Zhang ◽  
Shi Hai Zhang ◽  
Ya Nan Yu

For a coordinate measurement system based on binocular vision, system calibration is an important factor for measurement accuracy. In this paper we present a flexible calibration method for the axis calibration of rotation stage which is installed in front of the binocular vision system to increase the system measurement range. By putting a standard ball in front of the binocular vision system, a sequence of pictures is taken by the two cameras with a few different rotation angles of the rotation stage. With the method of space intersection of two straight lines, the reference points (the ball centers at each rotation angles) for axis calibration are figured out. The trail of standard ball is a circle. Since all ball centers of rotation are on a plane perpendicular to the axis, the center of circle is on the axis of rotation stage. The rotation axis of stage is then calibrated according to the calibration model.


1999 ◽  
Author(s):  
Chunhe Gong ◽  
Jingxia Yuan ◽  
Jun Ni

Abstract Robot calibration plays an increasingly important role in manufacturing. For robot calibration on the manufacturing floor, it is desirable that the calibration technique be easy and convenient to implement. This paper presents a new self-calibration method to calibrate and compensate for robot system kinematic errors. Compared with the traditional calibration methods, this calibration method has several unique features. First, it is not necessary to apply an external measurement system to measure the robot end-effector position for the purpose of kinematic identification since the robot measurement system has a sensor as its integral part. Second, this self-calibration is based on distance measurement rather than absolute position measurement for kinematic identification; therefore the calibration of the transformation from the world coordinate system to the robot base coordinate system, known as base calibration, is not necessary. These features not only greatly facilitate the robot system calibration but also shorten the error propagation chain, therefore, increase the accuracy of parameter estimation. An integrated calibration system is designed to validate the effectiveness of this calibration method. Experimental results show that after calibration there is a significant improvement of robot accuracy over a typical robot workspace.


2007 ◽  
Author(s):  
Liwen Wang ◽  
Lei Zhang ◽  
Zhijing Yu ◽  
Fei Chen ◽  
Xiayan Si ◽  
...  

2008 ◽  
Vol 28 (11) ◽  
pp. 2181-2186
Author(s):  
徐巧玉 Xu Qiaoyu ◽  
车仁生 Che Rensheng

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