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arXiv 2306.08751cs.CV
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通过向同伴学习改进选择性视觉问答

Improving Selective Visual Question Answering by Learning from Your Peers

FAIR, Meta AI(Meta人工智能基础研究院);Reality Labs Research, Meta(Meta现实实验室研究院);Sorbonne Université(索邦大学)

Corentin Dancette, Spencer Whitehead, Rishabh Maheshwary, Ramakrishna Vedantam, Stefan Scherer, Xinlei Chen, Matthieu Cord, Marcus Rohrbach

AI总结:

针对视觉问答模型难以自主判断答案正确性、弃权决策效果不佳的问题,提出“向同伴学习(LYP)”方法训练多模态选择函数,无需额外标注,在分布内和混合分布场景下均大幅提升了选择性预测的覆盖率。

摘要:

尽管视觉问答(Visual Question Answering, VQA)领域已取得诸多进展,但模型评估自身答案正确性的能力仍未得到充分研究。近期研究表明,现成的VQA模型在答错时很难做到弃权(不执行)作答。弃权选项也被称为选择性预测,在向必须信任系统输出的用户(例如为视障用户提供服务的VQA助手)部署系统时极具实用价值。在这类场景中,弃权功能尤为重要,因为用户可能提供分布外(out-of-distribution, OOD)输入或对抗性输入,导致模型给出错误答案的概率升高。\n在本研究中,我们在分布内(in-distribution, ID)和分布外两种场景下探索选择性VQA任务,实验中模型会接收分布内与分布外混合的数据。该任务的目标是在最小化已答题目错误风险的前提下,尽可能提升可回答的问题数量。我们提出了一种简单却有效的“向同伴学习(Learning from Your Peers, LYP)”方法,用于训练多模态选择函数以做出弃权决策。该方法利用在训练数据不同子集上训练得到的模型的预测结果,作为优化选择性VQA模型的目标。它无需额外人工标注或留出数据,还能提供信号,用于识别容易/难以泛化的样本。\n在大量评估实验中,我们证明该方法能为不同架构、不同规模的多种模型带来性能提升。总体而言,在分布内场景下,我们的方法在1%错误风险下的选择性预测指标覆盖率(C@1%)达到32.92%,是该任务此前最佳覆盖率15.79%的两倍。在分布内/分布外混合场景下,利用模型的softmax置信度做弃权决策的效果极差,即便仅面对10%的分布外样本,在1%错误风险下能回答的问题占比还不到5%,但使用LYP方法训练得到的选择函数可将该指标提升至25.38% C@1%。

英文摘要:

Despite advances in Visual Question Answering (VQA), the ability of models to assess their own correctness remains underexplored. Recent work has shown that VQA models, out-of-the-box, can have difficulties abstaining from answering when they are wrong. The option to abstain, also called Selective Prediction, is highly relevant when deploying systems to users who must trust the system's output (e.g., VQA assistants for users with visual impairments). For such scenarios, abstention can be especially important as users may provide out-of-distribution (OOD) or adversarial inputs that make incorrect answers more likely. In this work, we explore Selective VQA in both in-distribution (ID) and OOD scenarios, where models are presented with mixtures of ID and OOD data. The goal is to maximize the number of questions answered while minimizing the risk of error on those questions. We propose a simple yet effective Learning from Your Peers (LYP) approach for training multimodal selection functions for making abstention decisions. Our approach uses predictions from models trained on distinct subsets of the training data as targets for optimizing a Selective VQA model. It does not require additional manual labels or held-out data and provides a signal for identifying examples that are easy/difficult to generalize to. In our extensive evaluations, we show this benefits a number of models across different architectures and scales. Overall, for ID, we reach 32.92% in the selective prediction metric coverage at 1% risk of error (C@1%) which doubles the previous best coverage of 15.79% on this task. For mixed ID/OOD, using models' softmax confidences for abstention decisions performs very poorly, answering <5% of questions at 1% risk of error even when faced with only 10% OOD examples, but a learned selection function with LYP can increase that to 25.38% C@1%.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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