High-speed 3D shape measurement by one pitch phase analysis method using brightness values in small square area of single-shot image

The authors have previously proposed one pitch phase analysis (OPPA) method in which the phase of a grating at a pixel point is analyzed using brightness values of one pitch of a projected grating of a single-shot image. Conventional phase-shifting method which uses several images during one-cycle shifting, cannot analyze moving objects. The OPPA method is useful to measure a 3D shape of moving objects in motion capture and vibration. However, since the method uses the brightness values in the oblong rectangular area of N × 1 pixels of the recording camera, the results are anisotropic and a wide area near the edge of an object has error. In this paper, a new phase analysis method using N brightness values in a small square area is proposed. The area with large error at the edge is reduced and the anisotropy is improved. The theory and the applications for motion capture are shown.