Re-Ranking Person Re-Identification With k-Reciprocal Encoding

Zhun Zhong, Liang Zheng, Donglin Cao, Shaozi Li; The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2017, pp. 1318-1327


When considering person re-identification (re-ID) as a retrieval process, re-ranking is a critical step to improve its accuracy. Yet in the re-ID community, limited effort has been devoted to re-ranking, especially those fully automatic, unsupervised solutions. In this paper, we propose a k-reciprocal encoding method to re-rank the re-ID results. Our hypothesis is that if a gallery image is similar to the probe in the k-reciprocal nearest neighbors, it is more likely to be a true match. Specifically, given an image, a k-reciprocal feature is calculated by encoding its k-reciprocal nearest neighbors into a single vector, which is used for re-ranking under the Jaccard distance. The final distance is computed as the combination of the original distance and the Jaccard distance. Our re-ranking method does not require any human interaction or any labeled data, so it is applicable to large-scale datasets. Experiments on the large-scale Market-1501, CUHK03, MARS, and PRW datasets confirm the effectiveness of our method.

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[pdf] [arXiv] [poster]
author = {Zhong, Zhun and Zheng, Liang and Cao, Donglin and Li, Shaozi},
title = {Re-Ranking Person Re-Identification With k-Reciprocal Encoding},
booktitle = {The IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
month = {July},
year = {2017}