Research On Measuring Speed Of Belt Conveyor Based On Machine Vision

In mining industry,belt conveyor is used extensively as transportation equipment.It has the advantages of high production efficiency and long transportation distance.Because belt conveyor plays the key role in industrial production,its running condition will immediate impact the efficiency of whole industrial production.Especially,the running speed is the core part of its running condition.In the process of monitoring speed,the measuring method and measuring effect should meet the requirements of industrial production.At present,the speed measurement of belt conveyor usually adopts the traditional contact method,which cannot avoid some potential problems and hidden dangers in the operation of belt conveyor.Firstly,the sliding phenomenon between the measuring instrument and the conveyor belt surface is a potential problem during continuous operation.Secondly,the wear of the measuring instrument may occur due to the long-term friction of the contact surface.Thirdly,the contact surface of belt can be scratched when the measuring instrument is damaged.The scratch problem can prevent the safe operation of the belt conveyor.Our research group has done a lot of research work around the belt conveyor,and has always been committed to surmount the drawbacks of the contact measuring speed method.With the dedication of the theory of machine vision,a new contactless speed measurement method based on optical flow technology is designed.The contactless method mainly relies on an optical camera placed under the lower surface of a belt conveyor.During the operation of belt conveyor,it can be found that most regions of the images are similar when the camera is set to high-speed continuous shooting mode.These similar image regions have a certain displacement change in the moving direction of the belt conveyor due to the time difference of its shooting,and can be described in a simplified way which is the image feature keypoint.The machine vision algorithm extracts image feature keypoints and acquires the optical flow information of image feature keypoints.In this method,an optical camera system is used to collect the images of the conveyor belt and a visual algorithm is used for real-time analysis,so as to obtain the motion displacement information to calculate the running speed.The entire design of the method includes visual algorithm programming and hardware platf-orm design.Finally,it is equipped with an experimental platform and verified.In the light of a large number of experiments,the effect of speed measuring results show that the contactless speed measuring method in this paper,the design method can overcome the limitation of existing contact speed measuring system,at the same time,the speed measurement method based on optical flow technology with the speed measurement precision of meeting the required standards.Therefore,it has the excellent ability of measuring precision about proposed contactless speed measurement target.It has a certain contribution to the development of contactless speed measurement technology of belt conveyor.