Reduction of measurement error induced by laser speckles in scanning operations by using a triangulation-based laser displacement sensor   Soichi Ibaraki, Yoshitomo Kitagawa, Yoshihiro Kimura, Shizuo Nishikawa       Abstract   A triangulation-based laser displacement sensor, using the diffuse reflection light, has a strong advantage in its robustness against the tilting of the object surface to the sensor’s sensitive direction. On the other hand, it is often subject to higher-frequency noise-like measurement error in high-speed scanning operations. This paper first reviews that it is caused by the speckle in the reflected laser beam spot. Then, a scheme to reduce this speckle-induced scanning error is proposed by using two CCD image sensors aligned symmetrically about the laser beam axis. Its effectiveness is verified by preliminary experimentation.   Key words: Triangulation-based laser displacement sensor, Speckle noise, Scanning, On-machine measurement         >> Back to Home