After the image lifting wavelet transformation, its coefficients have some characteristics, for example : the frequency compression characteristic, namely the primitive image energy majority of gathers to the low frequency sub-belt; spatial compression characteristic, namely high frequency sub-belt energy majority of centralisms in primitive corresponding and so on image edge, outline position; the coefficient distribution similarity, namely in the 经提升小波变换后,其系数具有如下特性:频率压缩特性,即原始图像的能量大部分聚集到低频子带;空间压缩特性,即高频子带的能量大部分集中在原始图像的边缘、轮廓等对应的位置;系数分布相似性,即同一方向上各级子带系数幅值分布大体一致。