Application Research of Fast UAV Aerial Photography Object Detection and Recognition Based on Improved YOLOv3

Abstract

UAV aerial photography is affected by weather, altitude, illumination, occlusion and other factors resulting in the objective fact that the object has many variations in scale and perspective. This paper proposes an improved YOLOv3 algorithm which achieve object detection and recognition in view of the above complex working conditions quickly and accurately. Firstly, the network framework of YOLOv3 is altered and the BN layer is integrated into the convolution layer. The network structure is simplified and the speed of model detection is greatly accelerated but the detection accuracy is almost the same as original. Secondly, GIOU is adopted as the loss function for bounding box regression to prevent the existence of zero gradient and improve mean average precision (mAP) of the detection model. Finally, the network combines predictions from multiple feature maps with different resolutions to naturally handle objects of various sizes independently. The results of a large number of comparative experiments show that the improved YOLOv3 algorithm can achieve object detection for the UAV aerial photography faster and more accurately. The detection speed is increased by 27%, the mAP is increased by 2.32% and the detection performance is also improved for small object significantly compared with YOLOv3.