%0 Journal Article
%T On the Usage of a Wavelet Coefficient Model in Noise Variance Estimation of Image<br>一种小波系数模型在图像噪声参数估计中的应用
%A Xie Jie-cheng
%A Zhang Da-li
%A Xu Wen-li
%A <br>谢志成
%A 张大力
%A 徐文立
%J 电子与信息学报
%D 2004
%I 
%X During wavelet image processing, the variance of Gaussian white noise is usually estimated in the finest HH subband. A popular method, proposed by Donoho and Johnstone, is often found to provide too large an estimate. To tackle this problem, this paper presents a new method. The new method takes the rude estimate from Donoho's method as the starting point, and then a subband more dominated by noise is produced with the signal filtered out by a filter derived from statistics theory and a newly-proposed coefficient model, the doubly stochastic process. Thus a finer estimate is possible by using Donoho's method on the filtered HH subband. Through employing EM algorithm, the new method can be straightly extended to the case of non-Gaussian noise. Experimontal results show that the new method can improve the estimate quite much when compared to Donoho's method.
%K Coefficient model
%K EM algorithm
%K Wavelet transformation<br>系数模型
%K EM算法
%K 小波变换
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=1319827C0C74AAE8D654BEA21B7F54D3&jid=EFC0377B03BD8D0EF4BBB548AC5F739A&aid=C3BBBC8235D3D441&yid=D0E58B75BFD8E51C&vid=96C778EE049EE47D&iid=94C357A881DFC066&sid=B28C697BC3A1BA62&eid=DA280A426E11FC95&journal_id=1009-5896&journal_name=电子与信息学报&referenced_num=5&reference_num=8