Coal mine rock burst and coal and gas outburst image perception alarm method based on depth characteristics

Rock burst and coal and gas outburst are easy to cause serious accidents in coal mines. In view of the current coal mine rock burst and coal and gas outburst accidents occurring by manual discovery, combined with the color and depth characteristics of mining face and roadway space cause by the disaster that are different from normal working conditions, a coal mine rock burst and coal and gas outburst image perception alarm method based on depth characteristics is proposed. Firstly, visible light binocular cameras with supplementary light lamps are arranged at multiple points in the roof of the roadway, near the roof of the laneway's side and in or near the top of the hydraulic support of the mining face to collect real-time color and depth images of working face and roadway; Secondly, the production equipment in coal mines with distinct color differences to the coal rocks thrown out by disasters is used as the background equipment to monitor and identify whether there is a significant change in the color of the color image; Third, when the end, the middle and the entrance of the driving roadway, or the mining face, or the entrance and the middle of the air inlet roadway, or the entrance and the middle of the return air roadway, or the main transportation and auxiliary transportation roadway and other positions of the visible light binocular camera to monitor the image color changes greatly, then monitor whether the average brightness of the color image is less than the set brightness threshold; Fourthly, when the average brightness is less than the set brightness threshold, the depth image is monitored with the production equipment that has a distinct color difference from the coal rocks thrown by the disaster as the background. Fifth, when the depth image changes greatly, whether the moving speed of the object resulting in a large change in the depth image is greater than the set speed threshold(v>13 m/s) is monitored; Sixth, When the moving speed is greater than the set speed threshold, methane sensors arranged at multiple points are used to monitor the methane concentration in the monitoring area, and when the methane concentration of coal mining face, driving face, inlet roadway, return roadway, total return roadway and other different locations were detected increased significantly or reached the alarm value, then the coal and gas outburst alarm is carried out, otherwise, the rock burst alarm is carried out. A method to determine the optimum dip angle of visible light binocular camera is proposed, and a method to determine the moving speed of objects that cause great changes in depth image is proposed. On the premise of ensuring security, simplifying the disaster simulation experiment, a set of experimental equipment to simulate the color and depth characteristics of rock burst and coal and gas outburst is designed: the 10 mm rubber balls with similar color and specific gravity of coal rock is used to replace the disaster throwing coal rocks; and the 315 mmPVC tubes is used to simulate the confined space of the roadway and the background equipment with distinct color difference from the coal rock thrown from the coal mine; and the axial flow high pressure blower is used as the power device to simulate the abnormal characteristics of color and depth of mining face and roadway caused by a large number of coal and rock during the occurrence of rock burst and coal and gas outburst; and the visible binocular camera with focal length of 3.4 mm, 30FPS and field of view angle of 71°×55° is used to complete the whole disaster simulation process monitoring and visible binocular image acquisition. Research and analysis show that the proposed method can identify the color and depth characteristics when the disaster occurs, and verify the feasibility and effectiveness of the image perception alarm method of rock burst and coal and gas outburst based on depth characteristics. © 2024 China Coal Society. All rights reserved.