  A novel multi-focus image fusion algorithm performed in spatial domain based
on similarity characteristics is proposed incorporating with region
segmentation. In this paper, a new similarity measure is developed based on the
structural similarity (SSIM) index, which is more suitable for multi-focus
image segmentation. Firstly, the SSNSIM map is calculated between two input
images. Then we segment the SSNSIM map using watershed method, and merge the
small homogeneous regions with fuzzy c-means clustering algorithm (FCM). For
three source images, a joint region segmentation method based on segmentation
of two images is used to obtain the final segmentation result. Finally, the
corresponding segmented regions of the source images are fused according to
their average gradient. The performance of the image fusion method is evaluated
by several criteria including spatial frequency, average gradient, entropy,
edge retention etc. The evaluation results indicate that the proposed method is
effective and has good visual perception.
