Papers › Parametric Classification for Generalized Category Discovery: A Baseline Study

Parametric Classification for Generalized Category Discovery: A Baseline Study

21 Nov 2022ICCV 2023 1arXiv:2211.11727archive 2025-07-28

Xin Wen, Bingchen Zhao, Xiaojuan Qi

Generalized Category Discovery (GCD) aims to discover novel categories in unlabelled datasets using knowledge learned from labelled samples. Previous studies argued that parametric classifiers are prone to overfitting to seen categories, and endorsed using a non-parametric classifier formed with semi-supervised k-means. However, in this study, we investigate the failure of parametric classifiers, verify the effectiveness of previous design choices when high-quality supervision is available, and identify unreliable pseudo-labels as a key problem. We demonstrate that two prediction biases exist: the classifier tends to predict seen classes more often, and produces an imbalanced distribution across seen and novel categories. Based on these findings, we propose a simple yet effective parametric classification method that benefits from entropy regularisation, achieves state-of-the-art performance on multiple GCD benchmarks and shows strong robustness to unknown class numbers. We hope the investigation and proposed simple framework can serve as a strong baseline to facilitate future studies in this field. Our code is available at: https://github.com/CVMI-Lab/SimGCD.

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Tasks

ClassificationNovel Class DiscoveryOpen-World Semi-Supervised LearningRepresentation Learning

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Open-World Semi-Supervised Learning CIFAR-10 SimGCD (ViT-B-16) All accuracy (50% Labeled) 97.0 #4 of 5 Archive leaderboard report
Open-World Semi-Supervised Learning CIFAR-10 SimGCD (ViT-B-16) Novel accuracy (50% Labeled) 98.5 #4 of 5 Archive leaderboard report
Open-World Semi-Supervised Learning CIFAR-10 SimGCD (ViT-B-16) Seen accuracy (50% Labeled) 93.9 #4 of 5 Archive leaderboard report
Open-World Semi-Supervised Learning ImageNet-100 (TEMI Split) SimGCD (ViT-B-16) All accuracy (50% Labeled) 83.6 #1 of 5 Archive leaderboard report
Open-World Semi-Supervised Learning ImageNet-100 (TEMI Split) SimGCD (ViT-B-16) Novel accuracy (50% Labeled) 79.1 #1 of 5 Archive leaderboard report
Open-World Semi-Supervised Learning ImageNet-100 (TEMI Split) SimGCD (ViT-B-16) Seen accuracy (50% Labeled) 92.4 #1 of 5 Archive leaderboard report

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