Deformation information extraction of similar material model based on image intelligent processing

Similar material model experiment is an important means to study mining subsidence and damage, and it is very important to obtain high-precision model deformation information in the experiment. There are still some limitations in the accuracy and efficiency of data acquisition in many existing model deformation measurement methods. In this paper, the simulation experiment of similar materials is carried out by taking the circular mining and filling mining of multiple coal seams in a mine in northern Shaanxi as models, and the high-resolution sequence images are obtained by using the non-measurement camera at close range. Through image distortion correction, automatic stitching and feature recognition, the deformation of similar material models can be obtained with high precision. Firstly, the influence of model measuring point marks and camera parameters on deformation measurement accuracy is analyzed, and the best model shooting scheme is determined, that is, the non-measurement camera is used to take an orthographic photo at a distance of 1.5−2.0 m from the model, forming an image sequence with a horizontal overlap of more than 55% and a vertical overlap of more than 30%; Furthermore, the bilinear interpolation method is used to correct the distortion of the obtained image, the automatic and robust image mosaic algorithm is used, the Harris corner detection operator is used to extract the feature points, the RANSAC algorithm is used to classify the pseudo-matching points, and a series of automatic processing processes such as color transition and smoothing at the butt edges are used to mosaic the image sequence. The resolution of the generated panoramic image of the model is about 10 times higher than that of the conventional fixed camera. In the process of image processing, the measuring point mark is used as the training network, the confidence level is added based on Faster R-CNN algorithm, and the appropriate sliding template is selected for region analysis, which significantly improves the recognition rate and accuracy of the measuring point mark. The results show that the precision of measuring point coordinate extraction in model experiment is better than 0.027 mm, which is equivalent to the field measurement precision of 5.4 mm, which fully meets the requirements of mine similar material model experiment. By making an experimental model with a scale of 1∶200, the deformation and failure characteristics of overlying strata caused by cyclic mining of multiple coal seams are simulated and analyzed, and the maximum surface subsidence reaches −18.937 mm; When the mined-out area is filled, the lower part of overlying rock is slightly deformed, and the surface subsidence is not more than 2 mm. The experimental results provide an effective technical means for the efficient and accurate collection of experimental data of similar material models in mines.