A novel angle position detector for application to pattern recognition

Simulating the function of biological retina using electronic hardware is the future trend for intelligent electronics. It is believed that the first three features that a biological visual system extracts from an object image are edge position, edge orientation and angle position. The contrast edge position of an object and its orientation with respect to the horizontal line can be measured from the active hollow FOur QUadrant Orientation Detector (FOQUOD). Based on this device, a double FOQUOD device which can extract the angle position is proposed for the first time and has been fabricated successfully. The a-Si:H angle position detector is composed of two hollow FOQUODs packed in a concentric fashion and each FOQUOD consists of four a-Si:H p-i-n solar cells.