In this research, we focused low illumination video image of “below 1 lux” obtained by normal type video camera, and we have considered the method of image correction for moving-object detection by inter-frame differencing. The method of this research is the combination of gamma correction and denoising as the preparation of inter-frame differencing. In this paper, F-measure was introduced as objective value, and the number of denoising was estimated by using k-means clustering. As the result, we had the feeling that the estimation using F-measure is proper. But it was shown that estimation using k-means had to be improved.