| 1. | 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。 |