arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2201.07200cs.CV
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针对低注释预算优化主动学习

Optimizing Active Learning for Low Annotation Budgets

Université Paris-Saclay(巴黎-萨克雷大学);CEA(法国原子能与可替代能源委员会);CentraleSupélec(中央理工-高等电力学院)

Umang Aggarwal, Adrian Popescu, Céline Hudelot

摘要:

当我们不能假设大量的注释数据时,主动学习是一个很好的策略。它包括在少量注释数据(注释预算)上学习模型,并选择最佳点集进行注释,以改进先前的模型并获得泛化。在深度学习中,主动学习通常被实现为一个迭代过程,其中通过微调来更新连续的深度模型,但它仍然带来了一些问题。首先,最初一批带注释的图像必须足够大,以训练深度模型。这样的假设是强有力的,特别是当总注释预算减少时。我们通过使用受迁移学习启发的方法来解决这个问题。使用预先训练的模型作为特征提取器,并且在活动迭代期间仅学习浅分类器。第二个问题是概率或特征估计的早期模型AL任务的有效性。通常仅基于最后学习的模型使用采集函数来选择用于注释的样本。我们引入了一种新的采集函数,它利用AL过程的迭代性质以更稳健的方式选择样本。在最后两个学习模型预测之间存在最大不确定性偏移的样本是有利的。一个多样化的步骤被添加到选择样本的分类空间的不同区域,从而在我们的方法中引入了代表性的组成部分。评估是针对竞争力的方法与三个平衡和不平衡的数据集,并优于他们。

英文摘要:

When we can not assume a large amount of annotated data , active learning is a good strategy. It consists in learning a model on a small amount of annotated data (annotation budget) and in choosing the best set of points to annotate in order to improve the previous model and gain in generalization. In deep learning, active learning is usually implemented as an iterative process in which successive deep models are updated via fine tuning, but it still poses some issues. First, the initial batch of annotated images has to be sufficiently large to train a deep model. Such an assumption is strong, especially when the total annotation budget is reduced. We tackle this issue by using an approach inspired by transfer learning. A pre-trained model is used as a feature extractor and only shallow classifiers are learned during the active iterations. The second issue is the effectiveness of probability or feature estimates of early models for AL task. Samples are generally selected for annotation using acquisition functions based only on the last learned model. We introduce a novel acquisition function which exploits the iterative nature of AL process to select samples in a more robust fashion. Samples for which there is a maximum shift towards uncertainty between the last two learned models predictions are favored. A diversification step is added to select samples from different regions of the classification space and thus introduces a representativeness component in our approach. Evaluation is done against competitive methods with three balanced and imbalanced datasets and outperforms them.

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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