基于块位长的小波嵌入零块编码算法

针对小波编码算法在编码过程需要占用大量内存的问题,提出了一种基于块位长的小波嵌入零块编码算法.该算法通过以下几项措施来减少编码过程的内存占用,同时提高编码的工作效率:(1)LLn子带单独编码;(2)提出位长定义,建立块位长位图;(3)通过位长位图代替排序,细化链表,减少内存占用;(4)通过位长位图的树结构来快速搜索重要块,克服重复扫描,加快编码速度.软件测试结果表明,对一幅512 pixel×512 pixel×8 bit的图像,该算法占用的内存空间为SPECK算法的1/27;硬件实现结果显示,雷达图像质量测试完全达到国际标准;该算法在保持高信噪比的同时,有效地减少了编码过程的内存占用,易于硬件实现.

Embedded block wavelet coding method based on block bit-length

An embedded block wavelet coding method based on block bit-length is put forward for resolving the problem of occupying a large amount of memory in coding process for a wavelet coder.The memory occupancy can be reduced and coding efficiency can be improved through four measurements in the coding process.The four measurements mentioned above are:(1) LLn sub-band is separately coded;(2) Block bit-length chart in terms of bit-length defined by the author is established;(3) The space of memory is saved by employing bit-length chart instead of fining lists and ranking processes;(4) The key blocks are searched by constructing bit-length chart to overcome the repeat scan and to improve the coding speed.The software experimental results show that for a piece of 512 pixel×512 pixel×8 bit image,occuping memory space by proposed method is 1/27 that of SPECK,the performance of radar image derived from hardware test can satisfiy the international standard.Meanwhile,proposed method can keep the high quality of PSNR and can be implemented through hardware easily.