Low-complexity near-lossless image coder for efficient bus traffic in very large size multimedia SoC

With dramatic development of image sensor technology, an image resolution of a digital camera has significantly increased recently. However, frequent memory access of such large-size images often brings out huge bus traffic in image processing chips or SoC´s embedded in digital cameras. Bus traffic is a critical issue in real-time image processing. This paper presents a computationally efficient near-lossless image coder to mitigate the bus traffic problem. First, the coder can encode a large image data of up to 6K×4K to write to the memory in near-lossless or lossless form with a desired compression ratio. Second, the operating speed of the coder is extremely fast so that it can be easily applied to real-time AV applications with large image resolution. Third, the coder provides much less complexity than typical standard near-lossless coders such as JPEG-LS. So, the proposed coder may cause only a negligible area overhead in SoC implementation. Finally, the coder can adaptively change its compression ratio adaptively with the bus traffic. Simulation results show that the proposed coder provides reasonable coding performance with much less complexity than the existing coders.