Study on coal-rock interface characteristics change law and recognition based on active thermal excitation

For recognizing the coal-rock interface efficiently, the infrared thermal images of coal-rock interface excited by active thermal excitation are tested and extracted which results in rise of coal and rock with different spatiotemporal characteristics and the infrared temperature attenuation law of coal and rock surface are analysed. The coal-rock infrared image is segmented and denoised to recognize the coal-rock interface with different ratio. The experimental results show that: (1) Under the active thermal excitation, the infrared temperatures of coal, rock and transition layer increase at different rates with a faster temperature growth of coal and the growth of rock temperature is relatively gentle. With the increase of excitation distance, the temperature decreases gradually and fluctuation of surface temperature occurs due to closer distance;(2) No matter the coal seam or the rock stratum, the temperature decreases linearly during the cooling process; (3) The results of image recognition technology based on local optimization and adaptive radius constrained principal curve algorithm are consistent with the actual test samples of coal rock ratio and the maximum error is 0.56%. The analysis results in coal-rock interface recognition for improving the cutting efficiency of shearer and realizing intelligent drum height adjustment control.