Improvement of accuracy of shape measurement using DMD reflection-type CCD camera

摘要

We previously developed a DMD(Digital Micro-mirror Device) reflection-type CCD camera that we call 'DMD camera' and we applied the DMD camera to shape measurement. In this former method, the integral values at a point are obtained by the averaging with the surrounding 9 pixels. This method, therefore, causes a problem that errors are caused by misalignment between the CCD pixel and the DMD pixel. In this paper, we propose a method to improve the algorithm to obtain the phase of a projected grating by phase-shifting method using correlation. The transferred on/off pattern to the DMD are modified and the integral values at a point are obtained by the averaging with the vertical 4 pixels. The accuracy of the shape measurement is improved using the proposed method. The principle, an experimental result, and a comparison of the accuracy between the former method and the proposed method are shown.