钻孔图像展开与拼接方法研究
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中图分类号：TD67 文献标志码：A
Research on unwrappingand stitchingmethods for borehole images
DENG Libo，WANG Xiaolong （CCTEGXi'anResearch Institute （Group） Co.，Ltd.，Xi'an 710077，China）
Abstract： Generating panoramic borehole wallimages and "virtual cores" through image unwrapping and stitchingis thebasis forquantitativeanalysisof geological structures andisalsoanurgent need in borehole investigation.Toaddress the problems of blurred image contours and discontinuous stitching in existing borehole image unwrapping and stitching methods，an image unwrapping method based on the Random Sample Consensus （RANSAC） algorithm and an image stitching method based on the Speeded Up Robust Features （SURF） plus Maximum Likelihood Estimation Sample Consensus （MLESAC）algorithm were proposed.The RANSAC algorithm was used to perform circle fiting onborehole edge datato obtain the borehole centerand borehole nner diameter，thereby determining theefective annular image region.Bycombining thecoordinate transformation algorithm and bilinear interpolation method，the effective annular region was then unwrapped into arectangular image，which effectivelycompensated forgeometric distortioncaused byprobe jiterandachieved high-precision unwrapping of borehole images.The SURF algorithm was used to rapidly extract feature pointsof adjacent imagesand perform coarse matching while maintaining feature stability under image rotation and scale transformation.The MLESAC algorithm was then used to perform precise matching of the extracted feature points，remove mismatched points，and select the optimal matching pairs，thereby estimating horizontal and vertical offset parametersandachievingglobal high-precision stitching ofvideo images.Comparativeanalysis results showed that，compared with the image unwrappng and stitching methods used in existing devices，the proposed method produced panoramic borehole wallimages that were continuous and uninterrupted， with highresolution detail， and significantly improved both stitching quality and visual quality.
Key Words： borehole image; image unwrapping; image stitching; RANSAC; SURF; MLESAC
0引言
岩体中裂隙、断层、节理、破碎区等结构面的属性、分布及发育特征，是决定岩体结构稳定性、力学特性与工程适用性的关键要素。（剩余11289字）
