Overlap classification mechanism for skeletal bone age assessment

The bone development is a continuous process, however, discrete labels are usually used to represent bone ages. This inevitably causes a semantic gap between actual situation and label representation scope. In this paper, we present a novel method named as overlap classification network to narrow the semantic gap in bone age assessment. In the proposed network, discrete bone age labels (such as 0-228 month) are considered as a sequence that is used to generate a series of subsequences. Then the proposed network makes use of the overlapping information between adjacent subsequences and output several bone age ranges at the same time for one case. The overlapping part of these age ranges is considered as the final predicted bone age. The proposed method without any preprocessing can achieve a much smaller mean absolute error compared with state-of-the-art methods on a public dataset.