A layered tone-mapping operator based on contrast enhanced adaptive histogram equalization

Nowadays, high dynamic range (HDR) images have been widely used in photography, video processing and visual reality. In order to display HDR image on the ordinary low dynamic range devices, a technique named tone-mapping is introduced to reform its intensity value and produce a low dynamic range (LDR) image while keeping high contrast and rich detail. According to the work [1–5], the operators are always divided to two kinds of tone-mapping operators: spatially varying and spatially uniform. In the paper, we propose a new spatially varying operator based on the layered iCAM06 model and contrast enhanced adaptive histogram equalization. We first decompose the HDR image into base layer and detail layer, and then apply the contrast enhanced operator to both layers. Last, we experiment the operator on a series of HDR luminance image, and get satisfactory result with improved contrast and visual sensation, as well as lowered time cost with respect the original iCAM06 operator. The results are illustrated in detail and evaluated with contrast and entropy. It shows that our operator improves the contrast and details, as well as the visual sensation of all the LDR images comparing to the original operator.