高级检索

    基于基元相关性描述子的图像检索

    Image Retrieval Based on Texton Correlation Descriptor

    • 摘要: 图像检索系统性能很大程度上取决于提取的图像描述子,其中颜色差分直方图(color difference histogram, CDH)已经在图像检索中显示出了较好的性能.但是这种描述子仍然有一定的局限性:1)只考虑到了像素间颜色差分的整体分布;2)忽略像素间的空间位置分布.因此提出了1种新的基元相关性描述子(texton correlation descriptor, TCD)提取图像特征,并将其应用于图像检索系统中.具体提取过程分为3个步骤:1)利用图像底层特征(颜色和局部二值模式)检测一致性区域,选择图像中包含区分性信息的局部区域;2)提出颜色差分特征和基元频率特征分别描述图像像素间的对比度和空间位置信息,其中颜色差分特征融合了描述局部邻域的颜色差分相关性统计和全局颜色差分直方图,基元频率特征也融合了描述局部邻域的基元频率相关性和基元频率直方图;3)联合一致性区域中的这2种特征得到最后的TCD描述子.这种特征描述了图像中2种互相独立并互相补充的特性:对比度和空间位置关系,并同时考虑到了这2种特性在局部和全局区域中的描述,因此在图像检索实验中会有更好的性能.在图像数据集中的实验结果显示了TCD描述子的检索效果明显优于其他几种特征描述子,证实了TCD描述子在图像检索中的有效性和稳定性.

       

      Abstract: The performance of content-based image retrieval (CBIR) depends to a great extent on the image feature descriptor. Among these descriptors, color difference histogram (CDH) has showed the great discriminative performance in CBIR. However, there are still some limitations in it: 1)only taking color difference of pixels in global region into account; 2)not considering the spatial structure among pixels. In this paper, to solve these problems, we propose a novel image representation, called texton correlation descriptor (TCD), which is applied to CBIR. First, we define uniform regions which contain discriminative information of images and then detect them by analyzing the relationship among low-level features (color value and local binary patterns) of pixels. Second, in order to character contrast and spatial structure information in uniform regions respectively, we propose the color difference feature which fuses color difference correlation and global color difference histogram, and texton frequency feature which fuses texton frequency correlation and texton frequency histogram. Finally, by combining these feature vectors, TCD not only characters two orthogonal properties: spatial structure and contrast, but also takes these properties in local and global uniform regions into account simultaneously so that TCD has better performance in CBIR. The experimental results show that the retrieval results of TCD is higher than that of other descriptors in image datasets, and thus demonstrate that TCD is more robust and discriminative in CBIR.

       

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