Image Contrast Improvement Based on Differential Gray-levels Histogram
When a captured image does not have good contrast, a method for improving its contrast that converts gray-levels based on the distribution of gray-levels included in the image is generally applied. A resultant image with good contrast does not always generated because the conventional method does not use a spatial feature included in an input image. This paper proposes a method for contrast improvement that can enhance differential gray-levels in an image in order to generate a resultant image with clearness and good contrast. The proposed method determines a gray-level of each pixel according to a Look-up-table generated from a histogram to represent a distribution of differential gray-levels. The experimental results show that the resultant images with natural and clear contrast were generated by the proposed method.