Research On Coal Mine Roadway Deformation Measurement System Based On Line Scanning Principle

With the rapid development of coal industry,the modern coal mine safety mining puts forward higher requirements on the monitoring of coal mine roadway deformation safety.The traditional coal mine roadway deformation monitoring methods have defects such as small measurement area,discontinuous measurement interval and difficult to guarantee the stability and accuracy of measurement under the harsh coal mine environment,which have gradually failed to meet the demand of coal mine roadway deformation monitoring in the coal mining process.At present,the visual measurement technology is widely used in the field of industrial intelligent inspection because of its characteristics of high real-time and non-contact measurement,among which the visual measurement system based on line scan has gradually become a research hotspot because of its simple structure,high accuracy,wide measurement range and high efficiency.In order to solve the problems of small measurement range,low measurement accuracy and efficiency in traditional coal mine roadway deformation measurement,this paper designs a coal mine roadway deformation measurement system based on line scan principle to realize online real-time monitoring of coal mine roadway deformation and help modern coal mine safety mining.Firstly,based on the actual working conditions and measurement requirements of coal mine roadway environment,this paper proposes the performance parameters of coal mine roadway deformation measurement system,designs the overall structure of the line scan coal mine roadway deformation measurement system,explains the working principle of the measurement system,analyzes in detail the transfer relationship between multiple coordinate systems in the measurement system and deduces its coordinate conversion model.Secondly,the hardware parameters such as camera,line scan laser and rotating motor are analyzed in detail and reasonably selected according to the actual performance index of the measurement system.Then,a tessellated camera calibration method is used to obtain the specific camera parameters of the measurement system,and an optical plane calibration method based on the tessellated target is adopted to study the optical plane calibration of the measurement system,which is completed by constantly changing the tessellated target attitude to obtain the pixel coordinates of the optical plane under the corresponding attitude.The optical stripe center extraction problem is studied,and an improved optical stripe center extraction algorithm with skeleton refinement and weighted gray center of gravity is proposed based on the traditional extraction method,which successfully solves the problem of difficult optical stripe center extraction due to the influence of uneven optical stripe,small optical stripe occupation and noise and diffuse reflection light interference.Finally,the hardware experimental platform of the line scan coal mine roadway surface deformation measurement system was built,and the calibration experiment of the experimental platform of the measurement system was completed,based on which the 3D reconstruction experiment of the coal mine simulation roadway was conducted.The measurement error characteristics of the system were obtained by comparing the set deformation and the measured deformation of the experimental platform.The results show that the coal mine roadway deformation measurement system designed in this paper can realize the non-contact measurement of roadway deformation,and its measurement accuracy is better than 7 mm.