In this paper, an efficient patch-based image fusion approach for raw images of single-chip imaging devices incorporated with the Bayer CFA pattern is presented. The multi-source raw Bayer pattern images are firstly parted into half overlapped patches. Then, the patches with maximum clarity measurement defined for raw Bayer pattern image are selected as the fused patches. Next, all the fused local patches are merged with weighted average method in order to reduce the blockness effect of fused raw Bayer pattern image. Finally, the real color fused image is obtained by gradient based demosaicing...