Shift-invariant three-dimensional object recognition by means of digital holography

We present an optoelectronic method to analyze three-dimensional (3D) scene s that is able to detect the presence, and also the position and orientatio n, of a reference 3D object. The data-acquisition procedure is based on dig ital holography. A phase-shifting interferometer records a single digital F resnel hologram of the 3D scene with an intensity-recording device. Hologra phic information of the 3D reference object is also obtained with the same method. Correlation techniques are then applied to recognize the presence a nd position of the 3D reference object in the 3D scene. The technique also allows us to detect the 3D reference with a small out-of-plane rotation. Pr eliminary experimental results are presented that demonstrate the theory. ( C) 2001 Optical Society of America.