基于四元小波与对数极坐标的不变纹理检索

为提高旋转与缩放情况下纹理图像的检索准确率，提出一种基于四元小波与对数极坐标的不变纹理图像检索方法。通过对数极坐标变换使旋转与缩放变化的图像产生水平或垂直移位，利用四元小波变换对移位图像进行分解，从而获得图像旋转与缩放的不变特征。使用Rayleigh分布对QWT高频子带进行建模，并将Kullback-Leibler距离作为图像特征的相似度量。在Brodatz数据库上的实验结果表明，该方法的检索准确率较高。

Invariant Texture Retrieval Based on Quaternion Wavelet and Log-polar

To overcome the problem of low retrieval rate for scaled and rotated texture image,this paper proposes an effective Rotation and Scale(RS) invariant features extraction method based on quaternion wavelet and Log-polar.It uses Log-polar transformation to make the rotated and scaled image shift along horizontal and vertical directions.Quaternion Wavelet Transform(QWT) is employed to decompose the image transformed by Log-polar and the RS invariant feature of the image is obtained.The proposed method computes Rayleigh distribution as the invariant feature based on the coefficients of QWT high frequency subbands and uses Kullback-Leibler Distance(KLD) as the similarity measure of features.Experimental results show that the proposed method can improve the retrieval accuracy of image.