Adaptive Calculation of Division Points for Piecewise Linear Transformation and Application in Image Enhancement

Piecewise linear transformation is usually used to increase the contrast of image efficiently. It is most important to select division points during the processing course of piecewise linear transformation because these division points can decide the quality and efficiency of image enhancement. But the proper division points are usually selected after several experiments which take a lot of time. In this paper, division points are automatically computed based on minimum error threshold which can increase the efficiency greatly. The whole image is divided into three sections based on the gray level. Different procession methods such as extension, maintenance and compression are carried on to these different sections. Experiments show that piecewise linear transformation is more valid to improve image quality comparing with other methods such as histogram equalization, linear transformation.