A low-power subsample-based image compression algorithm for capsule endoscopy

This paper presents an efficient sub-sample based image compression algorithm targeted to the endoscopic application. Endoscopic images are converted from RGB to YCgCo plane; the non-significant color components are then sub-sampled to obtain better compression ratio without heavily affecting the reconstruction quality. The algorithm uses simple integer-based Discrete Cosine Transform followed by a division-free quantization stage that results in low-cost implementation. The scheme is applied to both the traditional wide band images (WBI), as well as the narrow band images (NBI) for the performance assessment. The overall compression ratio and PSNR for the WBI and NBI are 84.53% and 82.36%, and 40.64 dB and 41.24 dB respectively. The hardware implementation is also presented that shows that the proposed scheme results in longer battery life compared to other existing schemes.