Anchor-free YOLOv3 for mass detection in mammogram

Abstract

Automatic detection of mass in mammograms is a big challenge and plays a crucial role in assisting radiologists for accurate diagnosis. Applying excellent deep learning based detection networks to medical image is a direction. In this paper, an anchor-free YOLOv3 network is proposed for mass detection in mammogram. The main improvements are as follows. Anchor-based (AB) detection scheme may involve too many negative boxes, which may aggravate the unbalance between positive boxes and negative boxes. Aiming at this problem, a novel anchor-free (AF) detection scheme is developed for box regression. To alleviate the problem caused by using mean square error (MSE) as box regression loss, generalized intersection over union (GIoU) loss is adopted to train bounding box regression. Focal loss is adopted as the objectness prediction loss, which can prevent the network degradation caused by the vast number of easy negatives. Moreover, a new feature aggregation manner by summing is designed and employed in the up to down pathway. Comparative experiments are performed on two databases (publicly available dataset INbreast and private dataset TXMD). For INbreast dataset, the proposed method achieved 0.95 true positive rate (TPR) with 1.7 false positives per image (FPs/I). For TXMD dataset, the proposed method achieved 0.94 TPR with 5.75 FPs/I. Experimental results demonstrate that the proposed method outperforms YOLOv3 network and gets a promising result compared with existing mass detection methods.