This paper introduces the basic principles of image fusion, the structure models and applications, the brief image of the Mallat wavelet decomposition and reconstruction algorithms. The Matlab7.0 environment, the use of Daubechies wavelet (dB4) filter treatment of fusion images of the three orthogonal wavelet decomposition, using edge-preserving low-frequency coefficients, high-frequency coefficients of the largest energy, based on the rules of regional integration, and integration of image quality evaluati...