Question Type-Aware Debiasing for Test-Time Visual Question Answering Model Adaptation

In Visual Question Answering (VQA), addressing language prior bias, where models excessively rely on superficial correlations between questions and answers, is crucial. This issue becomes more pronounced in real-world applications with diverse domains and varied question-answer distributions during testing. To tackle this challenge, Test-time Adaptation (TTA) has emerged, allowing pre-trained VQA models to adapt using unlabeled test samples. Current state-of-the-art models select reliable test samples based on fixed entropy thresholds and employ self-supervised debiasing techniques. However, these methods struggle with diverse answer spaces linked to different question types and may fail to identify biased samples that still leverage relevant visual context. In this paper, we propose Question type-guided Entropy Minimization and Debiasing (QED) as a solution for test-time VQA model adaptation. Our approach involves adaptive entropy minimization based on question types to improve the identification of fine-grained and unreliable samples. Additionally, we generate negative samples for each test sample and label them as biased if their answer entropy change rate significantly differs from positive test samples, subsequently removing them. We evaluate our approach on two public benchmarks, VQA-CP v2, and VQA-CP v1, and achieve new state-of-the-art results, with overall accuracy rates of 48.13% and 46.18%, respectively.