Refined modeling and protection of grotto monastery based on ICP algorithm and Poisson algorithm

Cultural relics carry the precious heritage of historical culture and contemporary civilization, and their importance cannot be replaced. However, as a non renewable cultural heritage, grotto temples are facing many value threats and crises of rapid extinction. Due to the unique environment, diverse volume, and complex geometric structure of the cave temples, the protection of cultural relics faces enormous challenges, and digitization has become the most important and effective preventive protection method. In this study, a perfect modeling method is proposed, that is, using 3 D laser scanning technology to obtain the point cloud data of grottoes relics, near-up photogrammetry to obtain multi-angle and high-resolution two-dimensional image data, and obtaining the complete geometric model of grottoes through the fusion modeling of laser point cloud and image dense matching point cloud. In addition, according to the texture mapping problem of complex models, the high resolution mapping of the texture image is realized by using the weighted thin plate spline function, so as to obtain the high quality and high precision three-dimensional cultural relic model. The improved algorithm’s registration method performs better in terms of Euclidean distance residuals, with residuals mainly distributed in the range of 0.02 to 0.03 millimeters. In terms of texture mapping, the model mapping accuracy is adjusted by adjusting the constraints of control points. The grayscale values of 50 pixels around the control point show significant gradient changes in the X direction, while the changes in the Y direction are relatively small. These methods and technologies provide practical and effective means for the protection and preservation of cultural relics in cave temples, and will provide important references for future cultural relic protection work.