Mobile Visual Search with Word-HOG Descriptors

Visual text information is a descriptive part of many images that can be used to perform mobile visual search (MVS) with particularly small queries. In this paper, we propose a system that uses word patch descriptors for retrieving images containing visual text. A random sampling method is used to find duplicate word patches in the database and reduce the database size. The system achieves comparable retrieval performance to state-of-the-art image feature-based systems for images of book covers, and performs better than state-of-the-art text-based retrieval systems for images of book pages. Using visual text to provide distinctive features, our system achieves more than 10-to-1 query size reduction for images of book covers and more than 16-to-1 query size reduction for images of book pages.