Effective hybrid processor to compute image moments for pattern recognition.

A hybrid optical-digital processor is presented for computing the invariant moments of images in real time, which consists of a holographic mask, two lenses, a charge-coupled-device detector, and a microcomputer. The processor is tested by inputting some roman letters, and the produced results show that the invariant moments of a letter are approximately independent of shift and rotation and that the moments are distinct with different letters.