Kernel Self-Attention in Deep Multiple Instance Learning

Multiple Instance Learning (MIL) is weakly supervised learning, which assumes that there is only one label provided for the entire bag of instances. As such, it appears in many problems of medical image analysis, like the whole-slide images classification of biopsy. Most recently, MIL was also applied to deep architectures by introducing the aggregation operator, which focuses on crucial instances of a bag. In this paper, we enrich this idea with the self-attention mechanism to take into account dependencies across the instances. We conduct several experiments and show that our method with various types of kernels increases the accuracy, especially in the case of non-standard MIL assumptions. This is of importance for real-word medical problems, which usually satisfy presence-based or threshold-based assumptions.