论文标题
如何信任未标记的数据?实例可信度推断了几次学习
How to trust unlabeled data? Instance Credibility Inference for Few-Shot Learning
论文作者
论文摘要
基于深度学习的模型在许多计算机视觉任务中都表现出色,并且似乎超过了人类的表现。但是,这些模型需要大量昂贵的人类标记的培训数据和许多迭代来训练大量参数。这严重限制了其可扩展性到现实世界的长尾分布类别,其中一些类别具有大量实例,但只有少数手动注释。从如此有限的标签示例中学习被称为少数学习(FSL)。与利用元学习或数据增强策略以减轻这一极为数据筛选问题的先前艺术不同,本文提出了一种统计方法,称为实例可信度推断(ICI),以利用未标记实例的支持来支持几次射击视觉识别。通常,我们将自学成才的学习范式重新利用,以预测未标记的实例的伪标签,并通过从少数拍摄中训练的初始分类器,然后选择最自信的训练,以增强培训设置以重新培训分类器。这是通过构建具有偶然参数的(广义)线性模型(LM/GLM)来实现的,以模拟从(未标记的特征到其(伪)标签的映射,偶然参数的稀疏表示相应的伪标记实例的可信度。我们将伪标记实例的可信度沿其相应的附带参数的正则化路径进行排名,并保留了最值得信赖的伪标记的示例作为增强标记的实例。从理论上讲,在限制特征值,无竞争性和较大误差的轻度条件下,我们的方法可以保证从嘈杂的伪标记集中收集所有正确预测的实例。
Deep learning based models have excelled in many computer vision tasks and appear to surpass humans' performance. However, these models require an avalanche of expensive human labeled training data and many iterations to train their large number of parameters. This severely limits their scalability to the real-world long-tail distributed categories, some of which are with a large number of instances, but with only a few manually annotated. Learning from such extremely limited labeled examples is known as Few-shot learning (FSL). Different to prior arts that leverage meta-learning or data augmentation strategies to alleviate this extremely data-scarce problem, this paper presents a statistical approach, dubbed Instance Credibility Inference (ICI) to exploit the support of unlabeled instances for few-shot visual recognition. Typically, we repurpose the self-taught learning paradigm to predict pseudo-labels of unlabeled instances with an initial classifier trained from the few shot and then select the most confident ones to augment the training set to re-train the classifier. This is achieved by constructing a (Generalized) Linear Model (LM/GLM) with incidental parameters to model the mapping from (un-)labeled features to their (pseudo-)labels, in which the sparsity of the incidental parameters indicates the credibility of the corresponding pseudo-labeled instance. We rank the credibility of pseudo-labeled instances along the regularization path of their corresponding incidental parameters, and the most trustworthy pseudo-labeled examples are preserved as the augmented labeled instances. Theoretically, under mild conditions of restricted eigenvalue, irrepresentability, and large error, our approach is guaranteed to collect all the correctly-predicted instances from the noisy pseudo-labeled set.