For point cloud data obtained from 3D scanning devices, excessively large storage and long postprocessing time are required. Due to this, it is very important to simplify the point cloud to reduce calculation cost. In this paper, we propose a new point cloud simplification method that can maintain the characteristics of surface shape for unstructured point clouds. In our method, a segmentation range based on mean curvature of point cloud can be controlled. The simplification process is completed by maintaining the position of the representative point and removing the represented points using the range. Our method can simplify results with highly simplified rate with preserving the form feature. Applying the proposed method to 3D stone tool models, the method is evaluated precisely and effectively.

In Japan, lithic materials are very important evidences of human activity research in the Palaeolithic and Jomon periods, while refitting lithic materials is a complex and hard task. In our previous research, it is possible to refit lithic materials from a single stone core, while it is impossible to refit them from multiple stone cores. This paper proposes a new method for refitting mixture lithic materials by matching flake surfaces. Each of the input point clouds of lithic materials is segmented and simplified to obtain flake surfaces. Then, according to several refitting principles in archeology, the lithic materials are matched starting from a stone core by searching the best matching flake surface. The flake surfaces of matched lithic materials are reconstructed, and the matching process is repeated until all data are matched. The implementation of the new method can obtain good refitting results for experimental examples.