Papers › Part-based Pseudo Label Refinement for Unsupervised Person Re-identification

Part-based Pseudo Label Refinement for Unsupervised Person Re-identification

28 Mar 2022CVPR 2022 1arXiv:2203.14675archive 2025-07-28

Yoonki Cho, Woo Jae Kim, Seunghoon Hong, Sung-Eui Yoon

Unsupervised person re-identification (re-ID) aims at learning discriminative representations for person retrieval from unlabeled data. Recent techniques accomplish this task by using pseudo-labels, but these labels are inherently noisy and deteriorate the accuracy. To overcome this problem, several pseudo-label refinement methods have been proposed, but they neglect the fine-grained local context essential for person re-ID. In this paper, we propose a novel Part-based Pseudo Label Refinement (PPLR) framework that reduces the label noise by employing the complementary relationship between global and part features. Specifically, we design a cross agreement score as the similarity of k-nearest neighbors between feature spaces to exploit the reliable complementary relationship. Based on the cross agreement, we refine pseudo-labels of global features by ensembling the predictions of part features, which collectively alleviate the noise in global feature clustering. We further refine pseudo-labels of part features by applying label smoothing according to the suitability of given labels for each part. Thanks to the reliable complementary information provided by the cross agreement score, our PPLR effectively reduces the influence of noisy labels and learns discriminative representations with rich local contexts. Extensive experimental results on Market-1501 and MSMT17 demonstrate the effectiveness of the proposed method over the state-of-the-art performance. The code is available at https://github.com/yoonkicho/PPLR.

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AALS yoonkicho/pplr/pplr/trainers.py official repository ran MIT (permissive) · 9067438cb7c2950b · report
CrossEntropyLabelSmooth yoonkicho/pplr/pplr/trainers.py official repository ran · metamorphic tier: invariant MIT (permissive) · 0cf8fe3e43a36de3 · report
PGLR yoonkicho/pplr/pplr/trainers.py official repository ran MIT (permissive) · 378959d40ec771be · report
SoftTripletLoss yoonkicho/pplr/pplr/trainers.py official repository ran · metamorphic tier: invariant fingerprinted MIT (permissive) · 35bbbe24da4c2536 · report
PPLRTrainer yoonkicho/pplr/pplr/trainers.py official repository unverified MIT (permissive) · 9714571b1913309a · report

Tasks

Person Re-IdentificationPerson RetrievalPseudo LabelRetrievalUnsupervised Person Re-IdentificationUnsupervised Vehicle Re-Identification

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Unsupervised Person Re-Identification MSMT17 PPLR Rank-1 73.3 #7 of 12 Archive leaderboard report
Unsupervised Person Re-Identification MSMT17 PPLR Rank-10 86.5 #7 of 12 Archive leaderboard report
Unsupervised Person Re-Identification MSMT17 PPLR Rank-5 83.5 #7 of 12 Archive leaderboard report
Unsupervised Person Re-Identification MSMT17 PPLR mAP 42.2 #7 of 12 Archive leaderboard report
Unsupervised Person Re-Identification Market-1501 PPLR MAP 84.4 #8 of 23 Archive leaderboard report
Unsupervised Person Re-Identification Market-1501 PPLR Rank-1 94.3 #8 of 23 Archive leaderboard report
Unsupervised Person Re-Identification Market-1501 PPLR Rank-10 98.6 #8 of 23 Archive leaderboard report
Unsupervised Person Re-Identification Market-1501 PPLR Rank-5 97.8 #8 of 23 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

Methods

Label Smoothing

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