People Re-Identification with Local Distance Comparison Using Learned Metric

Guanwen ZHANG  Jien KATO  Yu WANG  Kenji MASE  

IEICE TRANSACTIONS on Information and Systems   Vol.E97-D   No.9   pp.2461-2472
Publication Date: 2014/09/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2013EDP7424
Type of Manuscript: PAPER
Category: Image Processing and Video Processing
multiple-shot re-identification,  local distance comparison,  multimodal distribution,  

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In this paper, we propose a novel approach for multiple-shot people re-identification. Due to high variance in camera view, light illumination, non-rigid deformation of posture and so on, there exists a crucial inter-/intra- variance issue, i.e., the same people may look considerably different, whereas different people may look extremely similar. This issue leads to an intractable, multimodal distribution of people appearance in feature space. To deal with such multimodal properties of data, we solve the re-identification problem under a local distance comparison framework, which significantly alleviates the difficulty induced by varying appearance of each individual. Furthermore, we build an energy-based loss function to measure the similarity between appearance instances, by calculating the distance between corresponding subsets in feature space. This loss function not only favors small distances that indicate high similarity between appearances of the same people, but also penalizes small distances or undesirable overlaps between subsets, which reflect high similarity between appearances of different people. In this way, effective people re-identification can be achieved in a robust manner against the inter-/intra- variance issue. The performance of our approach has been evaluated by applying it to the public benchmark datasets ETHZ and CAVIAR4REID. Experimental results show significant improvements over previous reports.