说明：  为提高基于内容的图像检索系统中纹理特征提取的有效性,提出了又一种纹理图像检索方法。该方法 利用非下采样 Contourlet变换对图像进行分解, 提取不同子带和不同方向变换系数矩阵的均值和方差为特征向量, 作 为数据库中纹理图像的索引,并利用两种不同的相似度函数计算图像之间的相似度,建立了一套基于示例查询图像 的纹理图像检索系统。实验结果表明,与小波包等特征提取方法相比, 该方法不仅能降低特征向量维数,而且能取得 更高的检索准确率和检索速度。
(To i ncrease t he vali d ity o f tex t ure feature ex tracti on in conten t-based i mage retrieva l syste m, a nove l approach for tex ture i m age retr ieva lw as proposed . Th i s approach w as based on theNonSubsamp l ed Con t our l et T ransform ( NSCT). The m eans and variab l es of NSCT co efficien tsm a trix i n d ifferen t s ubbands and var i ous directi ons were ex tracted to for m the feature vectors wh ich we re reg arded as i ndexes of tex t ure i mages i n i m age da tabase . Two s i m il ar ity functi ons were used to compute the si m ilar i ty bet w een i m ages . A tex ture re trieval sy stem based on query i m age w as deve l oped . Co m pared to the w ave let packag e transform, th i s approach can no t on l y reduce the di m ension o f feature vectors , but a l so get higher accu racy and speed of retr i eva. l)