Contrast limited adaptive histogram equalization (CLAHE) is used for improve the visibility level of foggy image or video. In this paper we used CLAHE enhancement method for improving the video quality in real time system. Adaptive histogram equalization (AHE) is different from normal histogram equalization because AHE use several methods each corresponding to different parts of image and used them to redistribute the lightness value of the image and in case of CLAHE ‘Distribution’ parameter are used to define the shape of histogram which produce the better quality result compare then adaptive histogram equalization (AHE). In this algorithm rayleigh distribution parameter are used which create bell shaped histogram. The drawback of AHE is work over homogeneous fog but CLAHE applied over both homogeneous and heterogeneous fog and single image and video system. And the second drawback of AHE is used ‘cumulation function’ which applied over only gray level image but CLAHE used both images colored and graylevel.