Active Learning With Task Consistency and Diversity in Multi-Task Networks

Aral Hekimoglu, Michael Schmidt, Alvaro Marcos-Ramiro; Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), 2024, pp. 2503-2512

Multi-task networks demonstrate state-of-the-art performance across various vision tasks. However, their performance relies on large-scale annotated datasets, demanding extensive labeling efforts, especially as the number of tasks to label increases. In this paper, we introduce an active learning framework consisting of a data selection strategy that identifies the most informative unlabeled samples and a training strategy that ensures balanced training across multiple tasks. Our selection strategy leverages the inconsistency between initial and refined task predictions generated by recent two-stage multi-task networks. We further enhance our selection by incorporating task-specific sample diversity through a novel feature extraction mechanism. Our method captures task features for all tasks and distills them into a unified representation, which is used to curate a training set encapsulating diverse task-specific scenarios. In our training strategy, we introduce a sample-specific loss weighting mechanism based on the individual task selection scores. This facilitates the individual prioritization of samples for each task, effectively simulating the sample ordering process inherent in single-task active learning. Extensive experimentation on the PASCAL and NYUD-v2 datasets demonstrates that our approach outperforms existing state-of-the-art methods. Our approach reaches the loss of the network trained with all the available data using only 50% of the data, corresponding to 10% fewer labels compared to the state-of-the-art selection strategy. Our code is available at https://github.com/aralhekimoglu/mtal.