Salience Preserving Image Fusion with Dynamic Range Compression

Gradient conveys important salient features in images. Traditional fusion methods based on gradient generally treat gradients from multichannels as a multi-valued vector, and compute its global statistics under the assumption of identical distribution. However, different source channels may reflect different important salient features, and their gradients are basically non-identically distributed. This prevents existing methods from successful salience preservation. In this paper, we propose to fuse the gradients from multi-channels in the concept of saliency. We first measure the salience map of each channel´s gradient, and then use their saliency to weight their contribution in computing the global statistics. Gradients with high saliency are properly highlighted in the target gradient, and thereby salient features in the sources are well preserved. Furthermore, we handle the dynamic range problem by applying range compression on the target gradient, and thereby halo effect is effectively reduced.