ADAPTIVE PATTERN-RECOGNITION WITH ROTATION, SCALE, AND SHIFT INVARIANCE

Mutually orthogonal pattern distortions are handled by an adaptive opt ical recognition system. A double-channel system is presented that imp lements pattern recognition with rotation, scale, and shift invariance . The recognition process is based on a two-stage operation: An object -independent determination of one distortion parameter (the scale, in the example presented here) is performed, and then the recognition is completed by a shift- and rotation-invariant optical correlator that i s adapted to the measured parameter. Thus, complete invariance to thre e distortion parameters is achieved by the combination of two channels . The overall process is performed efficiently and can be executed in real time.