Statistical Centroid-based Laser Striped Lighting Method for Surface Profilmetry

• Main Authors: Pai-Yao Chang, 張百耀
• Other Authors: Din-Chang Tseng
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/96952025323145853344

碩士 === 國立中央大學 === 資訊工程研究所 === 98 === In this study, we use striped lighting method to measure the 3-D surface structures. The centroid method was widely used for laser stripe extraction. The other methods such as Catmull-Rom splines interpolation, quadratic curve fitting, cubic curve fitting, and Gaussian curve fitting are also used for laser stripe extraction. In this study, we propose a new method which is modified from centroid method to extract laser stripes. We analyze the distribution of intensity variance of stripe profiles. Based on the distribution of intensity variance, we build up a table to give every location a weight value which can compensate the random error of laser stripe. We also propose a method to estimate the orientation of laser plane. Because the laser emitter is not always perfectly in a desired angle, it is hard to adjust the angle around the axis of rotation of the laser emitter. We analyze the relationship between the laser stripe from the image and the angle around the axis of rotation of the laser emitter. A formula is proposed to compensate the angle in every location of laser stripe. In the experiment, we compared the stability and performance of different laser stripe extraction methods. The resolution of the CCD camera is 1536×512. The FOV of the camera is about 16.45×5.48mm2. The laser emitter has 50mW diode power, 660nm wavelength, and 30° fan angle. The experimental results show that the statistical centroid method has high stability and good performance in laser extraction.