A modified H.264 intra-frame video encoder for capsule endoscope
The objective of this paper is to develop an ultra-low-power video compression processor for capsule endoscope to lower the RF transmitter bandwidth. In applications of capsule endoscope, it is imperative to consider battery life and performance trade-offs. Applying state-of-the-art video compression techniques may significantly reduce the image bit rate by their high compression ratio, but they all require intensive computation and consume much power from battery. There are also many fast video compression algorithms for reducing computation load; however, they may result in distortion of original image. A new video compression algorithm for gastrointestinal image based on H.264 Intra-frame encoder and its corresponding VLSI architecture are both proposed for low-power, high bite-rate wireless capsule endoscope. The algorithm exploits the characteristic of gastrointestinal image and H.264 intra-frame prediction technique to reduce computing complexity and save battery power consumption. As the result of implementation, the developed video compressor for 512-by-512 image sensor and 2 Mbits/sec RF transmitter costs 60 k gates and consumes 0.9161 mW power at 2 frames/sec while the average compression rate can be as low as 82%.