A Study on the Imaging Method for the Channel Wave Dispersion Curve Variability Function

When the channel wave passes through the abnormal body, the dispersion curve appears interval, dislocation, and discontinuity, resulting in the non-standard and large error of the “velocity-frequency” pickup result of the transmitted channel wave dispersion curve, which directly leads to the inaccurate tomography. Therefore, aiming at this problem, the imaging method of dispersion curve variability function is proposed: (1) count the breakpoints of dispersion curve according to three types; (2) set the weighting factor for the breakpoint according to the spectrum curve; (3) the variability function is constructed for the dispersion curve, and the corresponding variation value is obtained; and (4) the variability value is back projected into the imaging grid space to obtain the abnormal body information in the detection area. The example verification results show that the imaging results of this method are accurate and stable, and non-convergence is caused by cyclic iteration, which provides a new imaging mode for the detection of complex structures in coal seams.