A Real-Time Hardware System for Digital Processing of Wide-Band Video Images

A high-fidelity video digitizer/processor extracts spatial and gray-scale information from high resolution dynamic video imagery. The 15-MHz bandwidth 60/s images (fields) are low pass filtered to minimize aliasing and digitized in real-time at 20 million samples pe second (MS/s), 9 bits/sample; sequential fields are transferred to memory, retrieved from memory after computer image processing, and reconstituted at up to 40 MS/s into 60 field/s video of 525, 875, or 1225 lines/frame (two interlaced fields). A/D and D/A converters are synchronized with memory by a high-speed interface, composed of a central data interchange (DI), and 8 radially connected I/O ports. The DI connects the data paths of one or more ports, each communicating with one or more external devices. Separate 16-bit, 40 megawords/s, input and output data buses between each port and the DI allow data entry through any port to the DI and output from the DI through any port(s), even the same port from which the input originated. The A/D and D/A are served by a single port. Two other ports communicate with CDC 3500 and CDC 1700 computers. Yet another port controls up to two mega-words of core/solid-state memory, of which 358K word may be accessed at the full data rate. Storage rates into existing memory of 40 MS/s are achieved for 16–32 ms. The D1 has dual data buses and throughput processing capability (a binary scalar, high-speed RAM, and ALU) which allow simultaneous input of two digitized fields from separate sources, gray-scale processing, logarithmic conversion, subtraction of one field from the other, and storage of the difference image, all in real time. The device is programmed on-line by either computer via 64 microcoded commands.