Abstract: The overlapped Z-scan method is presented for two-dimensional discrete wavelet transform (2D-DWT). It can provide an efficient tradeoff between chip area and system power consumption as the internal memory size can be decreased sufficiently with few overheads of the external memory access. An efficient 2D-DWT architecture based on this method is proposed for JPEG2000. In comparison with the line-based scan method, the size of image is set as 256×256 and the scan width is set as 64 lines. Experiment results show that the size of internal memory, based on the proposed method, can be reduced by about 40% with no more than 7.14% overheads of external memory access.

摘要： 提出了二维离散小波变换 (Two-dimensional Discrete Wavelet Transform )的交叠Z形扫描方法，通过增加极少的片外存储器访问次数，大大减小了片内存储器的大小，在系统功耗和芯片面积之间取得了很好的平衡。设计出了基于该方法的JPEG2000小波变换器。试验结果表明，相于基于行扫描的方法，当图像大小为256×256，扫描宽度为64行时，该方法对片外存储器的访问次数增加不超过7.14%，而片内存储器的面积减少了40%左右。