The Dual-field Measurement Method Of Material Flow On Conveyor Belt Based On Machine Vision

Belt conveyors are the predominant mode of materials transport in production of mines.Knowing the material quantity transported by conveyors is important with reference to economics and workers,it is the core technology of production statistics,and it is an important basis for speed control.Belt conveyors are high energy consumption equipment,the efficiency is not low due to frequent half-load or empty operation.In order to achieve speed regulation in transient operations,the material flow on the belt needs to be monitored in real –time,as the basic input of a speed control system.In this paper,according to the actual demand for measurement of material flow,the existing material flow measurement methods were studied.After analyzing the principle and disadvantages of each measurement method,paper mainly solves the problems that the machine vision method requires precollection,and has low precision and limited installation position.A two-viewpoint measurement method based on machine vision for conveying material of the conveyor belt is proposed.This paper summarizes the structure and material characteristics of the belt conveyor.Based on the non-contact visual inspection theory,the optimization algorithm for the instantaneous cross-sectional area of the material is studied.The method uses two linear light sources mounted on the supports at the detection positions on both sides of the conveyor belt to form two laser lines perpendicular to the running direction of the conveyor belt on the upper and lower surfaces of the material and the conveyor belt.Using the cameras of the two upper and lower viewpoints to collect the contour images of the upper surface of the conveyor belt at the same detection position and the surface of the material and the lower surface of the carrier side conveyor belt,Image processing is performed on the acquired image,and the contour depth is obtained by camera calibration,image correction,and feature matching,so that the instantaneous cross-sectional area of the material flow is calculated and the measurement of the material flow rate of the conveyor belt is realized.In order to verify the measurement method,after analyzing the measurement requirements,the equipment and device were selected and designed.The dual-field measurement system based on machine vision of material flow on conveyor belt was established as an experimental platform for testing the measurement method.Several sets of measurement models were designed and static measurements were made and dynamic measurements were taken at different tape speeds.After the measurement,the factors affecting the results were analyzed.The results show that the accuracy of the system can reach more than 94.1%.The system is not constrained by the installation location and does not cause any damage to the operator.The research prospect is broad and it is easy to promote and apply.