A Contactless Measuring Speed System of Belt Conveyor Based on Optical Flow Techniques

Abstract

In mining operation, measuring the speed of a belt conveyor is important for safe and efficient production. The contact measurement system is the mainstream choice for existing measuring speed systems, but the contact method cannot avoid some potential problems and hidden dangers in the running process of belt conveyor. A novel contactless measurement system based on optical flow techniques is designed in this study, which can calculate running speed of belt conveyor in real time. During the operation of belt conveyor, it can be found that most regions of the images are similar when the camera is set to highspeed 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. Motion displacement information including the displacement change can be extracted by analyzing of optical flow information about captured images to calculate the running speed. The contactless measuring speed system is verified by experiments. Experimental results show that the measuring accuracy can be presented by indicators with RMSE of 0.042 m/s and MAE of 0.029 m/s.

Tests of Belt Linear Speed for Identification of Frictional Contact Phenomena

“…They are successfully employed in monitoring the operation of, e.g., belt transmission systems [ 6 ] or evaluating in small-scale the slippage and transverse vibration in belt drives [ 7 , 8 ]. Despite their high measurement accuracy declared by the manufacturers to be ≤0.01 m/s, a note should be made that the unsteady motion of the belt (lateral wandering) and transverse vibration which occur during the continuous recording of belt speed may disturb the signal and lead to permanent changes in the geometry of the rotators [ 9 ].…”

“…Publication [ 9 ] presents the results of speed tests with the use of a CCD camera pointed at the bottom side of the conveyor belt marked with special measurement marks. During the tests, the camera was switched to a high-speed multi-series photography mode.…”

Wide-area Operation Monitoring of Conveyors Using a Panoramic Vibration Camera

“…When monitoring a wide-area facility such as a material handling conveyor in ironworks, not only installation and measurement time but also maintenance and management costs, such as sensor replacement, become large bottlenecks that make it difficult to improve their efficiency. To realize the measurement of dynamic structural properties using high spatial resolution images, many video analysis methods such as digital image correlation, 17,18) sampling moiré pattern method, 19,20) and optical flow 21,22) have been reported. They perform video analysis based on the frame rate of a commercially available video camera, which enables the simultaneous monitoring of multiple objects.…”

Prospects of in-belt IMU sensors application for fault detection in mining conveyors

“…An automatic procedure for overheated idler detection in belt conveyors exploiting combined RGB and IR images was proposed in [11]. Another topic that was studied for diagnostics purposes using image processing methods is belt speed measurement [12]. In the recent research [13], the contact-less method of idlers diagnostics is proposed by the rotation speed deviation, which is detected with the image data from a standard video camera.…”