Development of a Laser Structured Fringes 3D Profile Measurement System

• Main Authors: Chien-Yuan Chen, 陳建元
• Other Authors: Fang-Jung Shiou
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/25002587692482051076

碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === This study aims to develop a prototype of a non-contact 3D measurement system using structured laser fringes projection method. The developed system mainly consists of five modules, namely, the laser structured fringes projection module, the image acquisition module, mechanism module, the software module, and the conveyer. The developed system is capable of measuring 3-D object profile. The system utilizes the laser structured fringes generated by a diffraction mask as active light source. The deformed fringes projected on the object were captured by a CCD camera. Some image processing, such as noise filtering, binarization, and thinning were executed. The workpiece profile were calculated by the developed software, based on the height vs. fringe-offset calibration results. The developed system can be applied to do the on-line measurement and the reverse engineering measurement. In order to verify the accuracy of the developed system, a semi-sphere of a table tennis ball was put on the conveyer to do the measurement. After doing the image acquisition and image processing, the 3D profile of the object has been calculated. The least square sphereness error of the partial spherical surface was about 0.0489 mm compared with the measurement using a coordinate measuring machine (CMM). A freeform surface part with four-convex-one-concave has also been tested. The measured result is quite consistent with the measurement using a CMM. The profile deviation was about 0.064 mm for the freeform surface part. The dynamic measurement tests have also been investigated for multi-fringes projection. The moving speed of 100 mm/s is achievable and the profile deviation was about -0.224 mm according to the test results.