Camera Calibration with Phase-Shifting Wedge Grating Array

Planar targets with known features have been widely used for camera calibration in various vision systems. This paper utilizes phase-shifting wedge grating (PWG) arrays as an active calibration target. Features points are encoded into the carrier phase, which can be accurately calculated using the phase-shifting algorithm. The 2 pi-phase points are roughly extracted with edge detection and then optimized by windowed bicubic fitting with sub-pixel accuracy. Two 2 pi-phase lines for each PWG are obtained using linear fitting method. The PWG centers that are used as feature points are detected through computing the intersections of 2 pi-phase lines. Experiment results indicate that the proposed method is accurate and reliable.