BFE-Net: Bidirectional Multi-Scale Feature Enhancement for Small Object Detection

Small object detection becomes a challenging problem in computer vision due to low resolution and less feature information. Making full use of high-resolution features is an important factor in improving small object detection. In this paper, to improve the utilization of high-resolution features, this work proposes the Bidirectional Multi-scale Feature Enhancement Network (BFE-Net) based on RetinaNet. First, this work introduces a bidirectional feature pyramid structure to shorten the propagation path of high-resolution features. Then, this work utilizes residually connected dilated convolutional blocks to fully extract high-resolution features of low-feature layers. Finally, this work supplements the high-resolution features lost in the high-level feature propagation process by leveraging the high-level guided lower-level features. Experiments show that our proposed BFE-Net achieves stable performance gains in the object detection task. Specifically, the improved method improves RetinaNet from 34.4 AP to 36.3 AP on the challenging MS COCO dataset and especially achieves excellent results in small object detection with an improvement of 2.8%.