POSITIONING OF NONCOOPERATIVE OBJECTS BY USE OF JOINT TRANSFORM CORRELATION COMBINED WITH FRINGE PROJECTION

Automated assembly and quality control require reliable systems for th e detection of the position and the orientation of complicated objects . Correlation methods are well suited, but they are affected by struct ured backgrounds, varying illumination conditions, and textured or dir ty object surfaces. Using fringe projection to exploit the three-dimen sional topography of objects, we improve the performance of a nonlinea r joint transform correlator. Positioning of noncooperative objects wi th subpixel accuracy is demonstrated. Additionally, the tilt angle of an arbitrarily shaped object is measured by projection of object-adapt ed fringes that produce a homogeneous fringe pattern in the image plan e. An accuracy of better than 1 degrees is achieved. (C) 1998 Optical Society of America.