Spatial Verification via Compact Words for Mobile Instance Search

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• 关键词：Mobile instance search ; Multiple photos ; Spatial verification
• 刊名：Lecture Notes in Computer Science
• 出版年：2017
• 出版时间：2017
• 年：2017
• 卷：10133
• 期：1
• 页码：356-367
• 丛书名：MultiMedia Modeling
• ISBN：978-3-319-51814-5
• 卷排序：10133

文摘

Instance search is a retrieval task that searches video segments or images relevant to a certain specific instance (object, person, or location). Selecting more representative visual words is a significant challenge for the problem of instance search, since spatial relations between features are leveraged in many state-of-the-art methods. However, with the popularity of mobile devices it is now feasible to adopt multiple similar photos from mobile devices as a query to extract representative visual words. This paper proposes a novel approach for mobile instance search, by spatial analysis with a few representative visual words extracted from multi-photos. We develop a scheme that applies three criteria, including BM25 with exponential IDF (EBM25), significance in multi-photos and separability to rank visual words. Then, a spatial verification method about position relations is applied to a few visual words to obtain the weight of each photo selected. In consideration of the limited bandwidth and instability of wireless channel, our approach only transmits a few visual words from mobile client to server and the number of visual words varies with bandwidth. We evaluate our approach on Oxford building dataset, and the experimental results demonstrate a notable improvement on average precision over several state-of-the-art methods including spatial coding, query expansion and multiple photos.