利用经过小波变换后的图像数据的能量大部分聚集在低频子带这一特点,针对小卫星星载计算机处理能力有限的客观情况,提出一种将预测编码和EZW编码相结合的图像压缩编码方法.通过有限的扫描次数,提取高频系数的重要系数。同时结合预测编码的方案,实现对低频系数几乎无损的压缩.实验证明,该方法能够使遥感图像的压缩同时具有较快的压缩速度和较好的压缩效果.
The good spatial-frequencial localization characteristic of wavelet transform make the energy of image congregate mostly in lower frequency subimage. Based on this characteristic, a coding algorithm which combines embedded zerotree wavelet (EZW) coding method with predicting coding method is presented to fit the limited computer resources in small-satellites. Heavyweight higher frequency coefficients are selected and coded by EZW coding algorithm and lower frequency coefficients are coded by predicting coding algorithm. The result indicates that with this coding algorithm the speed of image compression can be increased with good compression effect.