孔壁全景图获取中的图像拼接技术研究

Image mosaic techniques in catching panorama image of hole wall

采用钻井后数字摄像获取具有真实感的孔壁全景图以进行地质分析已成为地质勘测的重要方法之一。已有的全景图获取方法存在设备成本高或图像拼接效果不理想等不足。通过控制测井深度,对井下孔壁四周360度的柱面空间投影到像面上得到序列环带图像,并对图像进行展开,运用中值滤波算法对图像进行预处理,通过差值图像匹配原理找出图像的重叠部分进行配准,然后采用贝塞尔曲线的逼近算法对图像进行融合,实现图像间的平滑过渡,最后得到具有真实感的孔壁全景图。实际地质勘测应用表明,该图像拼接技术简单,处理灵活高效,所获取的孔壁全景图具有理想的效果。

Using borehole digital camera technique to obtain the realistic panorama image of the hole wall has become one of the major ways to conduct geological analysis in geological survey. The existing methods of getting panorama image have such shortcomings as high cost of the equipment, unsatisfactory result of image splicing, etc. In this paper, a new method of acquiring the realistic panorama image of hole wall was proposed. By controlling the well depth and projecting the 360-degree cylindrical space of hole wall under the well onto plane, the authors could get the sequence ring images of hole wall, then unfolded the images and preprocessed them through median filtering algorithm, found out the overlapping parts of the image by the difference image matching principle, and blended them using Bezier curves approximation algorithm to achieve a smooth transition between images. Practical application on geological survey shows that the image mosaic technique presented in this paper is simple, flexible, efficient, and can provide ideal result of the panorama images of the hole wall.