Panoramic Image Mosaic By Multiple Side-view Cameras In The Simulated Borehole

At present, many accidents in coal mine occur in the development zone of rock cracks. The geological conditions in this area are complicated. Therefore, it is very important to carry out geological exploration ahead of schedule. The digital panoramic borehole imaging technique can acquire panoramic images of borehole walls and perform geological analysis. However, the existing methods of panoramic image acquisition have many shortcomings, such as high cost of the equipment,low resolution expansion plan, etc. Therefore, this paper presents a camera model for horizontal annular uniform distribution of multiple CCD (Charge, coupled, Device) cameras. The image is obtained by lateral shooting of the 360 degree of the borehole wall, and then the panoramic image is obtained by image stitching technique. The method improves the resolution of the unfolded planar image, which is a new method for borehole inner wall imaging, and has a certain practicability.According to the theory and technology of distortion correction and image stitching process, this paper uses the C++ language in the OpenCV (Open Source Computer Vision Library) based library realizes multi camera side drilling panoramic image stitching, the work has been done as follows:1. In the phase of distortion correction, this paper uses Zhang Zhengyou checkerboard calibration method to eliminate the optical distortion caused by the wide-angle lens. This paper presents a method to non uniform interpolation which cans make image information loss caused by the curvature of boreholes restore, and achieved ideal results for the next step of image stitching of panoramic image get prepared.2. In the image mosaic stage, the image feature points of the corrected image are extracted by the SIFT algorithm, and the matching points of the image are selected by using the BBF (Best Bin First)algorithm based on the k-d tree, then the RANSAC(Random Sample Consensus) algorithm is used to eliminate the mismatches and obtain the transform moments. In the process of image fusion, weighted average method is used to finally obtain smooth and seamless panoramic images with borehole wall texture information.