Quality enhancement based on retinex and pseudo-HDR synthesis algorithms for endoscopic images

In this paper, we present a quality enhancement scheme for endoscopic images. Traditional algorithms might be able to enhance the image contrast, but possible over-enhancement also lead to bad overall visual quality which prevents surgeons from accurate examination or operations of instruments in Minimal Invasive Surgery (MIS). Our proposed scheme integrates the well-known retinex algorithm with a pseudo-HDR (High Dynamic Range) synthesis process, designed to compose of three parts: multiscale retinex with gamma correction (MSR-G), local brightness range expansion (brightness diversity), and bilateral-filter-based HDR image fusion. Experiment results demonstrate that the proposed scheme is able to enhance image details and keep the overall visual quality good as well, with respect to other existing methods.