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 經(jīng)提升小波變換后,其系數(shù)具有如下特性:頻率壓縮特性,即原始圖像的能量大部分聚集到低頻子帶;空間壓縮特性,即高頻子帶的能量大部分集中在原始圖像的邊緣、輪廓等對應(yīng)的位置;系數(shù)分布相似性,即同一方向上各級(jí)子帶系數(shù)幅值分布大體一致。