A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System
A light pen coordinate measuring system (LPCMS) is a kind of vision-based portable coordinate measuring technique. It implements coordinate measurement by analyzing the image of a light pen, which has several control points and a probe. The relative positions of control points need to be determined...
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| Format: | Article |
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MDPI AG
2020-09-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/20/19/5592 |
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| author | Sen Wang Shugui Liu Qing Mao |
| author_facet | Sen Wang Shugui Liu Qing Mao |
| author_sort | Sen Wang |
| collection | DOAJ |
| description | A light pen coordinate measuring system (LPCMS) is a kind of vision-based portable coordinate measuring technique. It implements coordinate measurement by analyzing the image of a light pen, which has several control points and a probe. The relative positions of control points need to be determined before measurement and serve as the measuring basis in LPCMS. How to accurately calibrate the relative positions of control points is the most important issue in system calibration. In this paper, a new method of control point position calibration based on a traditional coordinate measuring machine (CMM) is proposed. A light pen is fastened to the measuring arm of a CMM and performs accurate translational movement driven by the CMM. A camera is used to capture the images of control points at different positions, and the corresponding readings of the CMM are recorded at the same time. By establishing a separate coordinate system for each control point, the relative positions of the control points can be transformed to the differences of a series of translation vectors. Experiments show that the calibration repeatability of control point positions can reach 10 μm and the standard deviation of measurement of the whole LPCMS can reach 30 μm. A CMM is used to generate accurate translation, which provides a high accuracy basis of calibration. Through certain mathematical treatment, tremendous data acquired by moving the light pen to tens of thousands of different positions can be processed in a simple way, which can reduce the influence of random error. Therefore, the proposed method provides a high-accuracy solution of control point position calibration for LPCMS. |
| first_indexed | 2024-03-10T15:58:17Z |
| format | Article |
| id | doaj.art-d8b685b7bac44e668f7d9314f5ffbed5 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T15:58:17Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-d8b685b7bac44e668f7d9314f5ffbed52023-11-20T15:32:25ZengMDPI AGSensors1424-82202020-09-012019559210.3390/s20195592A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring SystemSen Wang0Shugui Liu1Qing Mao2State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, ChinaState Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, ChinaState Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, ChinaA light pen coordinate measuring system (LPCMS) is a kind of vision-based portable coordinate measuring technique. It implements coordinate measurement by analyzing the image of a light pen, which has several control points and a probe. The relative positions of control points need to be determined before measurement and serve as the measuring basis in LPCMS. How to accurately calibrate the relative positions of control points is the most important issue in system calibration. In this paper, a new method of control point position calibration based on a traditional coordinate measuring machine (CMM) is proposed. A light pen is fastened to the measuring arm of a CMM and performs accurate translational movement driven by the CMM. A camera is used to capture the images of control points at different positions, and the corresponding readings of the CMM are recorded at the same time. By establishing a separate coordinate system for each control point, the relative positions of the control points can be transformed to the differences of a series of translation vectors. Experiments show that the calibration repeatability of control point positions can reach 10 μm and the standard deviation of measurement of the whole LPCMS can reach 30 μm. A CMM is used to generate accurate translation, which provides a high accuracy basis of calibration. Through certain mathematical treatment, tremendous data acquired by moving the light pen to tens of thousands of different positions can be processed in a simple way, which can reduce the influence of random error. Therefore, the proposed method provides a high-accuracy solution of control point position calibration for LPCMS.https://www.mdpi.com/1424-8220/20/19/5592coordinate measuringvision metrologylight pencontrol point position calibrationCMMPnP problem |
| spellingShingle | Sen Wang Shugui Liu Qing Mao A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System Sensors coordinate measuring vision metrology light pen control point position calibration CMM PnP problem |
| title | A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System |
| title_full | A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System |
| title_fullStr | A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System |
| title_full_unstemmed | A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System |
| title_short | A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System |
| title_sort | cmm based method of control point position calibration for light pen coordinate measuring system |
| topic | coordinate measuring vision metrology light pen control point position calibration CMM PnP problem |
| url | https://www.mdpi.com/1424-8220/20/19/5592 |
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