%0 Journal Article
%T Research on Symmetric Extension in Subband Image Coding Systems<br>子带图象编码系统中对称扩展方法的研究
%A LU Xi
%A qun
%A CHEN Chun
%A <br>陆系群
%A 陈纯
%J 中国图象图形学报
%D 2001
%I 
%X In a subband image coding system, due to the non ideal characteristics of the analysis/synthesis filters and the decimation/interpolation operations, the reconstructed signal, in general, suffers from magnitude/phase distortions and aliasing errors. For finite length sequences (e.g. the image signals), besides the above errors, there is an additional error--the expansive effect around the borders due to linear convolution. Though the conventional symmetric extension and circular convolution are applied, the experiments show that the border distortion still exists in the reconstructed signal. The symmetric extension method is further studied in this paper and extended to the M channel linear phase perfect reconstruction filter banks. In this paper, different symmetric sequences are formulated in a unified form based on the circular symmetry framework. According to the period and the symmetric center of symmetric periodic sequences, four permissible types of symmetric extension are derived. The experiment shows that the reconstructed signal is free from distortion.
%K Subband image coding
%K Linear
%K phase perfect
%K reconstruction analysis/synthesis filter banks
%K Symmetric extension<br>图象子带编码
%K 综合滤波阵列
%K 对称扩展
%K 边界扩展效应
%K 滤波器
%K 线性卷积
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=8240383F08CE46C8B05036380D75B607&jid=D06194629680C940ACE75262F54B9D85&aid=1EA7F6DC775A8A3F&yid=14E7EF987E4155E6&vid=B31275AF3241DB2D&iid=59906B3B2830C2C5&sid=75AB4EF959CC4ED9&eid=CA21EE48F5BB8E19&journal_id=1006-8961&journal_name=中国图象图形学报&referenced_num=0&reference_num=8