Multi-focus image fusion via boundary finding and multi-scale morphological focus-measure

Multi-focus image fusion is to extract the focused regions from the multiple images of the same scene and combine them together to produce one fully focused image. The key is to find the focused regions from the source images. In this paper, we transform the problem of finding the focused regions to find the boundaries between the focused and defocused regions in the source images, and propose a novel image fusion method via boundary finding and a multi-scale morphological focus-measure. Firstly, a morphological focus-measure, consisted of multi- scale morphological gradients, is proposed to measure the focus of the images. Secondly, a novel boundary finding method is presented, which utilizes the relations of the focus information of the source images. Thirdly, the found boundaries naturally segment the source images into regions with the same focus condition and the focused regions can be simply selected by comparing the focus-measures of the corresponding regions. Fourthly, the detected focused regions are reconstructed to obtain the decision map for the multi-focus image fusion. Finally, the fused image is produced according to the decision map and the given fusion rule. Experimental results demonstrate the proposed algorithm outperforms other spatial domain fusion algorithms.