Three-dimensional object recognition by use of digital holography

We present a technique for performing three-dimensional (3D) pattern recogn ition by use of in-line digital holography. The complex amplitude distribut ion generated by a 3D object at an arbitrary plane located in the Fresnel d iffraction region is recorded by phase-shifting interferometry. The digital hologram contains information about the 3D object's shape, location, and o rientation. This information allows us to perform 3D pattern-recognition te chniques with high discrimination and to measure 3D orientation changes. Ex perimental results are presented. (C) 2000 Optical Society of America.