Research on error analysis and elimination technology of non-contact measurement technology in anti-vignetting glass detection

Author(s):  
Kaiyu Li ◽  
Xueliang Lv ◽  
Zijin Li ◽  
Jingming Zheng ◽  
Yong Sun ◽  
...  
2017 ◽  
Vol 870 ◽  
pp. 271-276
Author(s):  
Zhong Yu Wang ◽  
Zhen Jian Yao ◽  
Qi Yue Wang

The visual measurement technology is prerequisite to implement high accuracy pose measurement tasks for space manipulator. Firstly, a Newton Downhill-Least Square (ND-LS) algorithm is presented to optimize the object’s pose in this paper. Secondly, the pose measurement error caused by the focal ratio, the principal point, image coordinates and world coordinates is analyzed separately. Finally, the performance of suggested algorithm and the results of pose error analysis are evaluated respectively by re-projection error (RPE) and mean absolute of pose error (MAPE). Experimental results validate that the ND-LS algorithm is superior than Newton method or Least Square (LS) method in pose optimization. In general, solved by ND-LS algorithm, the RPE reduces nearly 3 times contrasted to initial value, and it also reduces to half of that obtained by both Newton method and LS method. On the other hand, the results of pose error analysis indicates that the error influenced by the principal point approximately equals to the one caused by image coordinates, about 2 and 15 times higher than what caused by both focal ratio and world coordinates, respectively, to orientation error with MAPE. Moreover, the relationships above are about 2 and 20 times separately as for the position error.


Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4680
Author(s):  
Xin Wen ◽  
Jingpeng Wang ◽  
Guangyu Zhang ◽  
Lianqiang Niu

The three-dimensional (3D) size and morphology of high-temperature metal components need to be measured in real time during manufacturing processes, such as forging and rolling. Since the surface temperature of a metal component is very high during the forming and manufacturing process, manually measuring the size of a metal component at a close distance is difficult; hence, a non-contact measurement technology is required to complete the measurement. Recently, machine vision technology has been developed, which is a non-contact measurement technology that only needs to capture multiple images of a measured object to obtain the 3D size and morphology information, and this technology can be used in some extreme conditions. Machine vision technology has been widely used in industrial, agricultural, military and other fields, especially fields involving various high-temperature metal components. This paper provides a comprehensive review of the application of machine vision technology in measuring the 3D size and morphology of high-temperature metal components. Furthermore, according to the principle and method of measuring equipment structures, this review highlights two aspects in detail: laser scanning measurement and multi-view stereo vision technology. Special attention is paid to each method through comparisons and analyses to provide essential technical references for subsequent researchers.


2021 ◽  
Vol 11 (2) ◽  
pp. 488
Author(s):  
Linshen Yao ◽  
Haibo Liu

Non-contact measurement technology based on triangulation with cameras is extensively applied to the development of computer vision. However, the accuracy of the technology is generally not satisfactory enough. The application of telecentric lenses can significantly improve the accuracy, but the view of telecentric lenses is limited due to their structure. To address these challenges, a telecentric surface reconstruction system is designed for surface detection, which consists of a single camera with a telecentric lens, line laser generator and one-dimensional displacement platform. The designed system can reconstruct the surface with high accuracy. The measured region is expanded with the used of the displacement platform. To achieve high-accuracy surface reconstruction, we propose a method based on a checkerboard to calibrate the designed system, including line laser plane and motor direction of the displacement platform. Based on the calibrated system, the object under the line laser is measured, and the results of lines are assembled to make the final surface reconstruction. The results show that the designed system can reconstruct a region of 20×40 mm2, up to the accuracy of micron order.


2021 ◽  
Vol 233 ◽  
pp. 04014
Author(s):  
Chang’an Hu ◽  
Linghui Kong ◽  
Fei Lv

With the continuous progress of computer and laser measurement technology, non-contact measurement based on laser scanning technology has been more and more applied in the industrial production process. Since the 1990s, 3D laser scanning technology used as a new technology has been developed rapidly. The 3D laser scanning technology, also known as High Definition Surveying (HDS), was based on the principle of laser ranging. The technology on the surface of a measured object can record some features of large dense points, including 3d coordinates, reflectance and texture information, so as to rapidly reconstruct 3D models of a measured target and various map data such as the line, the surface and the body. Meanwhile, it is a revolutionary leap that the technology improves the traditional single point measurement to the surface measurement, and realizes the digital reconstruction of the objects. Especially, for some conditions such as contact measurement and complex component detection that cannot be measured, 3D laser scanning technology has a natural advantage in the field of industrial design and measurement .


1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.


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