A fast multi-focus image fusion algorithm by DWT and focused region decision map

To comprise the advantages of both the spatial domain and transform domain methods, this paper presents a novel hybrid algorithm for multi-focus images fusion, which reduces the error rate of sub-band coefficients selection in the transform domain and reduce the artificial discontinuities created in the spatial domain algorithms. In this method, wavelet transforms are firstly performed on each input image, and a focused region decision map is established based on the high-frequency sub-bands extraction. The fusion rules are then guided by this map, and the fused coefficients are transformed back to form the fused image. Experimental results demonstrate that the proposed method is better than various existing methods, in term of fusion quality benchmarks. In addition, the proposed algorithm has a complexity proportional to the total number of pixels in the image, which is lower than some other algorithm which may produce similar fusion quality with the proposed algorithm. Furthermore, the proposed algorithm only requires one level wavelet decomposition, again reducing the processing time. With the proposed method, high quality and fast multi-focus image fusion is made possible.