Rendering High Dynamic Range Images by using Block level Processing and Median Filtering

Abstract

We propose new, efficient and effective tone reproduction techniques which preserve visibility, contrast, and natural impression of scenes, when rendering high dynamic range images on conventional low dynamic range display devices. The method is simple and easy to implement. Our new approach uses a modified mapping function which takes into account the block-level log-average, as well as the log-average of the whole image, which gives increased visibility in darker regions. Furthermore, local details of the image are enhanced by using a median filter. Experimental results show that the techniques give satisfactory results for a variety of images avoiding common artefacts, such as halos, gradient reversals, and loss of local contrast. Significantly, our method produces excellent results when an image has both of dark and bright regions owing to the new block-level processing during tone-mapping.