Lossless CFA Image Compression Chip Design for Wireless Capsule Endoscopy

Abstract

This paper presents a hardware-oriented lossless color filter array (CFA) image compression algorithm for very-large-scale integration (VLSI) circuit design. In order to achieve high performance, low complexity and low memory requirement, a novel lossless CFA image compression algorithm based on JPEG-LS is proposed for the VLSI implementation. A previous study showed the usage of a context table with its memory consuming more than 81% of the chip area for a JPEG-LS encoder design. The proposed algorithm implements a JPEG-LS-based lossless image compression algorithm that eliminates the use of the context technique and its memory in order to reduce the chip area while still maintaining its high performance. The proposed algorithm includes a pixel restoration, an adaptive Golomb-Rice parameter prediction and an improved Golomb-Rice coding technique. This paper was realized using a 0.18μ m CMOS process with synthesized gate counts and core area of 4.8 k and 57,625μm 2 , respectively. The synthesized operating frequency of this design reached 200 MHz by using a pipeline scheduling technique. Compared with the previous JPEG-LS-based designs, this paper reduced the gate count to at least 28% and increased the average compression ratio by over 17.15% using the video endoscopy images from the Gastro Gastroenterologist Hospital.