摘要

Existing feature dimensionality reduction algorithms are inherently designed for the case of classification, clustering and retrieval, but not for ranking applications such as visual search reranking. This is a serious limitation which restricts the applicability of existing dimensionality reduction methods as well as the generalization ability of ranking applications. Therefore, it is important to design a kind of special methods to be effectively employed for ranking applications. Fisher discriminant analysis (FDA) is one of the most popular dimensionality reduction methods. Thus, we propose a novel dimensionality reduction algorithm based on FDA to solve this kind of problem in this paper. Specifically, relevance degree information-the data label in ranking applications, is introduced to a semi-supervised form of FDA, in which both local information and unlabeled data are employed. We name the proposed method as ranking Fisher discriminant analysis (RFDA). To verify the effectiveness of