Abstract: Aiming at the problems of scene details being covered up and image information being difficult to obtain in non-uniform illumination images, we proposed a non-uniform illumination image enhancement method based on simulated exposure fusion. Firstly, an improved adaptive Gamma correction algorithm was used in HSV color space to process the brightness component  as a medium exposure image. Secondly, the over-exposure pixel set was divided by dynamic threshold for the brightness component, and the simulated over-exposure image was synthesized by using maximum information entropy estimation and camera response model. Thirdly, the improved quality measurement method and the weight optimization method based on the guided filtering were used to obtain the fused image for the multi-exposure image sequences composed of the original images, the medium-exposure images and the over-exposure images.  Finally, the fusion result was processed by multi-scale detail enhancement to obtain the final image enhancement result. The experimental results show that the proposed algorithm can effectively improve the visual effect of non-uniform illumination images. The comparison of subjective and objective evaluation data shows that the proposed algorithm is superior to similar algorithms.

Key words: non-uniform illumination, adaptive Gamma correction, simulated exposure image, multi-exposure fusion, guided filtering