Improving object retrieval quality by integration of similarity propagation and query expansion

Re-ranking is an essential step for accurate image retrieval, due to its well-known power in performance improvement. Although numerous works have been proposed for re-ranking, many of them are only customized for a certain image representation model. In contrast to most existing techniques, we develop generalized re-ranking algorithms that are applicable to different kinds of image encodings in this paper. We first employ a quite successful theory of similarity propagation to reconstruct vectors of a query and its top ranked images and, subsequently, get a re-ranked list by comparing the new image vectors. Furthermore, considering that the just mentioned strategy is directly compatible with query expansion and, thus, in order to leverage advantages of this milestone, we then propose integrating them into a unified framework for maximizing reranking benefits. Our re-ranking algorithms are memory and computation efficient, and experimental results on benchmark datasets demonstrate that they compare favorably with the state of the art. Our code is available at https://github.com/MaJinWakeUp/rerank.