A 0.2 b/pixel 16 mW real-time analog image encoder in 0.8 /spl mu/m CMOS

Portable video-camera applications require image compression with high compression ratio and extremely low power consumption. This real-time image encoder chip for such applications, fabricated in 0.8 /spl mu/m CMOS technology, processes analog image data from a B/W image sensor without ADCs and consumes 16 mW at 3 V supply to encode images that are 192 pixels wide and 228 lines at 60 Frame/s. For ordinary DCT-based digital processing schemes such as JPEG, 10 mW or more is consumed by only the core digital DCT processor in 0.3 /spl mu/m CMOS technology. This analog encoder uses switched capacitor techniques for analog arithmetic processing. By taking advantage of the compact nature of the processing units, massively parallel implementation makes it possible to decrease operating speed of each unit. The units use vector quantization for subband image compression. The encoder six-line parallel analog input decreases the input data rate and reduces the number of analog sample-holds. A CMOS imager that outputs data in parallel to directly interface with this encoder LSI is to be integrated with the encoder by reducing the layout size of the encoder.