Specialised parallel hardware for flash recognition of windowed images in a television frame

Parallel flash comparators are widely employed for digitising television images in real-time and the parallel flash recognition hardware (FRH) described maintains the same speed for image recognition by operating at the same pixel sampling rate, typically 5-10 MHz. The image processing time is thus at most 200 ns and recognition results obtained at the currently digitised pixel are available for display at the next pixel on the same TV line. The speed is thus the theoretical maximum for conventional scanning and the hardware is designed by CAD methods for defined windows up to 16×16 pixels, located at all possible pixel positions in the TV image. Preprocessing of the flash ADC grey scale binary coded output includes gradient detection and threshold