Late Fusion of Compact Composite Descriptors for Retrieval from Heterogeneous Image Databases

Compact composite descriptors (CCDs) are global image features, capturing more than one types of information at the same time in a very compact representation. Their quality has so far been evaluated in retrieval from several homogeneous databases containing images of only the type that each CCD is intended for, and has been found better than other descriptors in the literature such as the MPEG-7 descriptors. In this study, we consider heterogeneous databases and investigate query-time fusion techniques for CCDs. The results show that fusion is beneficial, even with simple score normalization and combination methods due to the compatibility of the score distributions produced by the CCDs considered.