Curvature-Driven Deformable Convolutional Networks for End-To-End Object Detection

Recently, deformable convolution networks have shown the superior performance in object detection due to its ability to adapt to the geometric variations of object. These methods learn the offset fields under the supervision of localization and recognition. Nevertheless, the spatial support of these networks may be inexact because the offsets are learned implicitly via extra convolutional layer. In this work, we present curvature-driven deformable convolutional networks (C-DCNets) that adopt explicit geometric property of the preceding feature maps to enhance the deformability of convolution operation and make the networks easier to focus on pertinent image region. To be consistent with postprocessing technology of object detection, we multiply the class prediction probability by the similarity of predicted boxes and ground truth boxes as the final class prediction probability and substitute it into the binary cross entropy loss function. The obtained loss function correlates the bounding box regression and classification. Experimental results on PASCAL VOC and COCO data set show that C-DCNets-based YOLOv4 with the proposed loss function outperforms state-of-the-art algorithms.