Accuracy Improvement of Semi-Supervised Segmentation Using Supervised ClassMix and Sup-Unsup Feature Discriminator

arXiv cs.CV / 4/9/2026

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Key Points

  • The paper proposes improving semi-supervised semantic segmentation by reducing the harm caused by noisy pseudo-labels generated from unlabeled images in the ClassMix-style framework.
  • It introduces a labeling strategy that pastes class labels (and regions) taken from labeled images onto unlabeled images, including their pseudo-labeled versions, to improve training signal quality.
  • It also adds a discriminator-based feature alignment approach that encourages predictions on unlabeled images to become more similar to those produced on labeled images.
  • Experiments on the Chase and COVID-19 datasets show an average 2.07% mIoU improvement over conventional semi-supervised learning methods, indicating practical effectiveness for segmentation tasks with costly pixel-level labeling.

Abstract

In semantic segmentation, the creation of pixel-level labels for training data incurs significant costs. To address this problem, semi-supervised learning, which utilizes a small number of labeled images alongside unlabeled images to enhance the performance, has gained attention. A conventional semi-supervised learning method, ClassMix, pastes class labels predicted from unlabeled images onto other images. However, since ClassMix performs operations using pseudo-labels obtained from unlabeled images, there is a risk of handling inaccurate labels. Additionally, there is a gap in data quality between labeled and unlabeled images, which can impact the feature maps. This study addresses these two issues. First, we propose a method where class labels from labeled images, along with the corresponding image regions, are pasted onto unlabeled images and their pseudo-labeled images. Second, we introduce a method that trains the model to make predictions on unlabeled images more similar to those on labeled images. Experiments on the Chase and COVID-19 datasets demonstrated an average improvement of 2.07% in mIoU compared to conventional semi-supervised learning methods.