Reassembly of broken objects using surface signatures

Abstract

As 3D object acquisition techniques and computational powers have been improved, research into the virtual reassembly of broken 3D objects has been actively conducted and techniques have been applied to various fields. However, the complicated and uneven shape of the fractured surfaces of broken objects makes it difficult to extract features for reassembling the object and forces us to use high-dimensional complex shape information. In addition, deformation of the fractured surface due to the small debris particles generated when the object is broken is one of the difficulties in this field. In this paper, we propose a surface signature descriptor that can easily and effectively represent the complicated fracture surface of a broken object. This descriptor is inspired by the human reassembly mechanism, which matches a convex region of a fractured surface to a concave region with a similar shape of another fractured surface. This descriptor is not dependent on the local geometry of fractured surfaces, so it has the advantage of being insensitive to the small noise that may exist in the fractured surface. In addition, it is simple and easy to calculate compared with the existing high-dimensional shape information. In the process of reassembling the actual broken object using the proposed surface signature descriptor, we propose and improve the segmentation, calculation of surface roughness and similarity measures, definition of the surface roughness, and similarity measurement technique between the fractured surfaces so that the complex fractured surface can be processed. The effectiveness of the proposed method is demonstrated through the realization of reassembly using actual broken objects. In addition, we propose a verification method through the creation of hypothetical fractured surfaces as a solution to the problem of the difficulty of the quantitative evaluation of reassembly technology due to the absence of verification data before a break. The virtual fractured surface is arbitrarily generated by several factors, and it can be evaluated in various aspects, such as accuracy, efficiency, and robustness against noise of the reassembly algorithm. The reassembly method proposed in this study is also evaluated. This study is meaningful, in that it developed and improved the techniques suitable for reassembly from the beginning of the reassembly, by defining a descriptor of the 3D fractured surface, to the qualitative evaluation of the methods. It could also be expanded to other research fields related with reassembly.