Abstract
In a digital still camera (DSC) system, in most cases, a dynamic range is compressed linearly in logarithmic space. Therefore, an image taken by DSC tends to be low contrast, and gives us a flat impression without liveliness in comparison with silver halide photography.
In this study, we propose a new digital image enhancement method by using sigmoid functions. In the proposed method, parameters of sigmoid functions are decided by local information of the input image for each pixel. Further, multiscale image enhancement is carried out by setting some scales of local regions, and the resultant image, that is visually good and high contrast, is provided by synthesizing enhanced images obtained by changing scale.
