Hierarchical Image Fusion Based on Wavelet Transform

Wavelet transform has the feature of multi-difference and has been used in image fusion. After image decomposed by wavelet, different entropy of low and high frequency parts are obtained in different decomposed layers. The emphases of image fusion can be obtained by analyzing the entropy of low and high frequency parts in different wavelet decomposed layers, and fusion methods can be accordingly used. The fusion of low frequency parts use improved energy fusion method in different wavelet decomposed layers, the fusion of high frequency parts use different computing expressions of grads on different detail directions. Satisfied vision and evaluation results are obtained by fusing two images using this method