Abstract
For PTV measurement in water, it is very impotant to correct the distortion of images due to refraction at the water-air boundary. The issue becomes more serious for three-dimensional PTV in which the optical axes of cameras are set diagonal to a air-water boundary. The correction becomes, though, more difficult in the condition, more precise correction is requested. In this paper, the new method, which enables the strict correction, is proposed. And it is adapted for the stereo-matching analysis.