Mixstyle-Entropy: Domain Generalization with Causal Intervention and Perturbation
Luyao Tang, Yuxuan Yuan, Chaoqi Chen, Xinghao Ding, Yue Huang
TL;DR
This work tackles domain generalization by reframing learning through a causal lens. It introduces InPer, a framework that combines entropy-based causal intervention during training (EnIn) with homeostatic-score guided causal perturbation during testing (HoPer), grounded in a structural causal model to disentangle domain-related signals from semantically relevant features. EnIn selectively perturbs high-entropy, domain-informative features to isolate causal content, while HoPer constructs a prototype classifier from causal-stable test samples and uses perturbation-based refinement constrained by HomeoScore. Across multi-source classification and semantic segmentation benchmarks, InPer achieves state-of-the-art results, with ablations confirming the contributions of EnIn and HoPer and practical guidance on patch size and testing protocols. The approach offers a plug-and-play path to robust DG with minimal additional parameters, highlighting the practical impact of incorporating causal interventions into both training and testing pipelines.
Abstract
Despite the considerable advancements achieved by deep neural networks, their performance tends to degenerate when the test environment diverges from the training ones. Domain generalization (DG) solves this issue by learning representations independent of domain-related information, thus facilitating extrapolation to unseen environments. Existing approaches typically focus on formulating tailored training objectives to extract shared features from the source data. However, the disjointed training and testing procedures may compromise robustness, particularly in the face of unforeseen variations during deployment. In this paper, we propose a novel and holistic framework based on causality, named InPer, designed to enhance model generalization by incorporating causal intervention during training and causal perturbation during testing. Specifically, during the training phase, we employ entropy-based causal intervention (EnIn) to refine the selection of causal variables. To identify samples with anti-interference causal variables from the target domain, we propose a novel metric, homeostatic score, through causal perturbation (HoPer) to construct a prototype classifier in test time. Experimental results across multiple cross-domain tasks confirm the efficacy of InPer.
