Abstract
In recent years, contrast improvement methods have been important image processing according to the spread of the products with camera. When the contrast of an image of photography is not good, a method to improve contrast by software is effective. The histogram equalization has been proposed as the typical conventional contrast improvement methods. This method generates an output image with a higher contrast because the output image has the maximum entropy. However, noises and intensive improvement may occur, and a resultant image may become unnatural. The purpose of this research is to propose a contrast improvement method that uses the feature analysis of an input image. Two image features are used in this method. First, the detail variance and the background variance are used to reduce noises and to set a clipping level. Second, the sharpness factor by the delta histogram is used to adjust improvement effect and to generate good contrast images. The experimental results show that the images that had good and natural contrast were generated by the proposed method.
