DCT压缩域中基于纹理和形状的图像检索算法

在对以往DCT压缩域的图像检索算法研究的基础上，将DCT块及其系数的空间分布信息引入特征提取算法，提出了一种压缩域中结合纹理和形状信息的图像检索算法．根据DCT块的复杂度及块内系数的空间分布，构造了加权复杂度直方图来表述图像的纹理信息;同时，根据DCT块系数的取值将其划分为不同的边缘类型，并采用边缘空间分布特征来描述图像的形状信息．该算法不仅考虑了DCT块的统计分布，又考虑了块内系数的空间分布，在一定程度上避免了由于DCT块统计分布信息相同而空间分布信息不同而造成的误检漏检情况．实验结果表明，该算法具有较好的检索结果．

Image retrieval based on the texture and shape in the DCT compressed domain

Image retrieval based on the texture and shape in the DCT compressed domain is proposed by introducing the spatial information of DCT blocks and DCT coefficients into the feature extraction. First, the definition of complex is introduced. Then, according to the complex of the DCT blocks and distribution of DCT coefficients, a weighted complex histogram is presented to extract the texture information. At the same time, DCT blocks are classified into different edges using the DCT coefficients directly and the edge-spatial distribution feature is adopted to describe the image shape. The statistical distribution of DCT blocks and the spatial distribution of DCT coefficients are taken into account in this paper, thus avoiding the wrong retrieval and missing retrieval. Experimental results show that the new method has a good performance in both retrieval efficiency and effectiveness.