Based on HSV Space Real-color Image Enhanced by Multi-scale Homomorphic

Digital image enhancement provides good dynamic range compression in each red, green and blue (RGB)channel, but it fails in color rendition. In this letter, we propose to transform a real-color image from RGB space to HSV space at first.Then, saturation channel is enhanced by Butterworth high-pass homomorphic filter and value channel is enhanced by multi-scale Gaussian high-pass homomorphic filters. In addition , we propose anew method to fix on the cut-off frequency of high-pass filter in homomorphic enhancement algorithm and explain the ratio coefficient of high-pass filter.Experiments show the compression of real-color image dynamic range is obviously effective, and it successes in color rendition.