Class–Domain Discriminability Guided Representation Enhancement for Domain Generalization

Domain Generalization (DG) aims to leverage multiple source domains to train models that can generalize to unseen target domains, thereby mitigating the performance degradation caused by domain shifts. Most existing approaches impose unified alignment or suppression constraints in the global feature space, overlooking the heterogeneity of feature channels in terms of class discriminativeness and domain stability. Such coarse-grained constraints may lead to the loss of discriminative information or the retention of domain-sensitive features. To address this issue, we propose a novel DG framework consisting of two core modules: Channel Sensitivity Decomposition (CSD), which employs channel-wise response variances along the class and domain dimensions as empirical proxy signals to partition feature channels into four functional subspaces via a continuous and differentiable soft decomposition mechanism; and Subspace-Specific Feature Augmentation (SSA), which implements tailored augmentation and regularization strategies for different subspaces to suppress environment-related spurious correlations while preserving cross-domain stable discriminative features. Additionally, a KL-divergence-based prediction consistency constraint is introduced to stabilize the training process and enhance model robustness. Extensive experiments on multiple standard DG benchmarks demonstrate that our framework consistently outperforms state-of-the-art methods.