Instance-Based Color Restoration Algorithm for Still/Dynamic Images taken under Low Illumination

Abstract

An instance-based algorithm to restore the color information of both still and dynamic images with high gradation is proposed. The 175 pairs of the color information (L^*a^*b^* colorimetric system) in color scheme cards under low and standard illumination are used as the instances. The color information of a pixel in the input image is restored with the most relevant instance to the color information of the pixel, by adding the difference between the low and the standard color information of the instance. The relevancy of an instance to the input pixel is determined by the color-difference based score, which is modified by considering its neighborhood pixels within a frame and the pixels calculated by optical flow between the previous frame and the processed frame. Experimental results using the surveillance system with CCD camera show that the proposed algorithm attains better performance in terms of the noise removal and color difference (about 10% shorter) compared with the conventional instancebased algorithm. The proposed algorithm gives the foundation for a surveillance camera system.