基于改进 YOLOv7 的煤矿带式输送机异物识别

Foreign object recognition of belt conveyor in coal mine based on improved YOLOv7

带式输送机煤流中会掺杂锚杆、角铁、木条、矸石、大块煤等异物,易导致输送带撕裂、转接处堵塞甚至断带。针对带式输送机巡检机器人难以在井下光照不均及带式输送机高速运行环境中高效、准确识别异物及模型部署不便等问题,以及YOLOv7模型对目标特征提取能力高,但识别速度较慢的特点,提出了一种基于改进YOLOv7的煤矿带式输送机异物识别方法。运用限制对比度自适应直方图均衡化方法对采集的带式输送机监控图像进行增强,提高图像中物体轮廓的清晰度;对YOLOv7模型进行改进,通过在主干提取网络引入轻量化无参注意力机制,提高模型对图像复杂背景的抗干扰能力和对异物特征的提取能力,同时引入深度可分离卷积代替主干特征提取网络中的普通卷积,提高异物识别速度;使用TensorRT引擎将训练后的改进YOLOv7模型进行转换并部署在NVIDIA Jetson Xavier NX上,实现了模型的加速。对煤矿井下分辨率为1920×1080的带式输送机监控视频进行识别,实验结果表明:改进YOLOv7模型的识别效果优于YOLOv5L和YOLOv7模型,识别精确率达92.8%,识别速度为25.64帧/s,满足精确、高效识别带式输送机异物的要求。

The coal flow of the belt conveyor will be mixed with anchor rod,angle iron,wood,gangue,and lump coal.This will easily lead to the tearing of the conveyor belt,the blockage of the transition and even the breakage of the belt.It is difficult for the inspection robot of the belt conveyor to efficiently and accurately recognize foreign objects in the environment of uneven lighting and high-speed running of the belt conveyor.The model deployment is inconvenient.The YOLOv7 model has a high capability to extract target features,but its recognition speed is slow.In order to solve the above problems,a foreign object recognition method of belt conveyor in coal mine based on improved YOLOv7 is proposed.The method of adaptive histogram equalization with limited contrast is used to enhance the collected monitoring image of the belt conveyor to improve the clarity of object contour in the image.The YOLOv7 model is improved by introducing a simple and parameter-free attention module into the backbone extraction network.The improved model can improve the model's antiinterference capability against the complex background of the image and the capability to extract foreign object features.The depthwise separable convolution is introduced to replace the ordinary convolution in the backbone feature extraction network to improve the speed of foreign object recognition.TensorRT engine is used to convert the improved YOLOv7 model after training and deploy it on NVIDIA Jetson Xavier NX,realizing the acceleration of the model.The video of the belt conveyor with the resolution of 1920×1080 in the underground coal mine is recognized.The experimental results show that the recognition effect of improved YOLOv7 is better than YOLOv5L and YOLOv7.The recognition accuracy rate is 92.8%,and the recognition speed is 25.64 frames/s,meeting the requirements of accurate and efficient recognition of foreign objects in the belt conveyor.