Compact combination of MPEG-7 color and texture descriptors for image retrieval

Multimedia databases are meaningfully indexed and retrieved with content based image retrieval (CBIR) systems. MPEG-7 standard describes visual descriptors and performance metrics for CBIR systems. Amongst all image features, color and texture are more visually expressive and hence are attractive for image retrieval descriptors enhances image retrieval and efficiency of a multimedia database. Further, combination of features makes image retrieval more relevant and robust. This paper proposes efficient methods for compactly representing color and texture features and combining them for image retrieval. The proposed methods use MPEG-7 visual descriptors namely, scalable color descriptor (SCD) for color and, homogeneous texture descriptor (HTD) for texture representation respectively. This paper investigates how compactly a descriptor could be defined and yet be used as a metric for image retrieval. If the descriptor is compact and yet performs meaningful image retrieval, then it is computationally efficient. Image classification, clustering and hierarchical modeling of image databases will benefit with such a representation. The performance of retrieval based on compact descriptors obtained by proposed techniques is analyzed with MPEG-7 metrics.