Application background The code is using stationary wavelet transform for multi focus image fusion, to obtain a clear image, prepared using MATLAB, can be directly run, with a pair of example images, experimental results. Key Technology First of all, SWT, SWT level stationary wavelet transform is a multi-scale, multi direction, frequency of local image sparse representation method, widely used in the field of image processing, but also has translation invariance, is very suitable for image fusion. SWT transform of the original image, the low frequency sub band and high frequency sub band, and then for different frequency bands, using different fusion rules to fuse.