Eiji Atsumi

Digital camera system built on JPEG2000 compression and decompression

Processing architecture for digital camera has been built on JPEG2000 compression system. Concerns are to minimize processing power and data traffic inside (data-bandwidth at interface) and out-side (compression efficiency) of camera system. Key idea is to decompose Bayer matrix data given from image sensor into four half-resolution planes instead of interpolating to three full-resolution planes. With a new compression standard, JPEG2000, capable of handling multi-component image, the four-plane representation can be encoded into a single bit-stream. The representation saves data traffic between image reconstruction stage and compression stage by 1/3 to 1/2 compared to the Bayer-interpolated data. Not only reduced processing power prior to and during compression but also competitive or superior compression efficiency is achieved. On reconstruction to full resolution is Bayer-interpolation and/or edge-enhancement required as a post-processing to a standard decoder, while half or smaller resolution image is reconstructed without a post-processing. For mobile terminals with an integrated camera (image reconstruction in camera h/w and compression in terminal processor), this scheme helps to accommodate increased resolution with all the limited data-bandwidth from camera to terminal processor and limited processing capability.