基于边界极限点特征的改进YOLOv3目标检测

目标数量多、尺度较小与高度重叠等问题导致目标检测精度低、难度大。为提升目标检测精度，尽可能避免漏检、误检情况，提出一种基于边界极限点特征的改进YOLOv3目标检测算法。首先，引入边界增强算子Border，从边界的极限点中自适应地提取边界特征来增强已有点特征，提高目标定位准确度；然后，增加目标检测尺度，细化特征图，增强特征图深、浅层语义信息的融合，提高目标检测精度；最后，基于目标检测中目标实例特性及改进网络模型，引入完全交并比（CIoU）函数对原YOLOv3损失函数进行改进，提高检测框收敛速度以及检测框召回率。实验结果表明，相较于原YOLOv3目标检测算法，改进后的YOLOv3目标检测算法的平均精度提高了3.9个百分点，且检测速度与原算法相近，能有效提高模型对目标的检测能力。

Improved YOLOv3 target detection based on boundary limit point features

The problems of large number of targets， small scale and high-overlapping lead to low accuracy and difficulty in target detection. In order to improve the precision of target detection and avoid missed detection and false detection as much as possible， an improved YOLOv3 target detection algorithm based on boundary limit point features was proposed. Firstly， a boundary enhancement operator Border was introduced to adaptively extract boundary features from the limit points of the boundary to enhance the features of the existing points and improve the accuracy of target positioning. Then， the precision of target detection was further improved by increasing the target detection scale， refining the feature map， and enhancing the fusion of the feature image deep and shallow semantic information. Finally， based on the target instance characteristics in target detection and the improved network model， the Complete Intersection over Union （CIoU） function was introduced to improve the original YOLOv3 loss function， thereby improving the convergence speed and recall of the detection box. Experimental results show that compared with the original YOLOv3 target detection algorithm， the improved YOLOv3 target detection algorithm has the Average Precision increased by 3.9 percentage points， and has the detection speed similar to the original algorithm， verifying that it can effectively improve the target detection ability of models.