Fractured Object Reassembly via Robust Surface Registration

Proceedings of the 35th International Symposium on Automation and Robotics in Construction (ISARC)

A major bottleneck activity in the process of restoration of Heritage Structures is the reassembly of its fragments. Computer-aided reassembly could assist in finding the relation between them thereby reducing time, manpower and potential degradation to fragile fragments. Using geometric compatibility between the adjacent fragments as the central idea, a reassembly framework for a three-dimensional shell is proposed as a logical extension of the twodimensional framework. Edges are extracted as polygons and relevant features are computed at each of its vertices. Sequences of the match for two fragments in the feature space are found using a modified version of Smith-Waterman Algorithm. Each match is assessed using a connectivity score. The final choice of best match is left to the user by displaying the resultant assembled fragments of prospective candidates along with the score. After pairwise matching, the global reassembly is done through a clustering-based method. This framework can handle fragments even with curved edges which can be reasonably approximated by a set of edges. We verify the methodology using a simulated dataset for both 2D pieces and a shattered 3D surface object.

2003 Conference on Computer Vision and Pattern Recognition Workshop, 2003

In the recent past, fragment matching has been treated in two different approaches, one using curve matching methods and one that compares whole surfaces or volumes, depending on the nature of the broken artefacts. Presented here is a fast, unified method that combines curve matching techniques with a surface matching algorithm to estimate the positioning and respective matching error for the joining of three-dimensional fragmented objects. Combining both aspects of fragment matching, essentially eliminates most of the ambiguities present in each one of the matching problem categories and helps provide more accurate results with low computational cost.

Lecture Notes in Computer Science, 2004

This paper proposes an efficient pairwise surface matching approach for the automatic assembly of 3d fragments or industrial components. The method rapidly scans through the space of all possible solutions by a special kind of random sample consensus (RANSAC) scheme. By using surface normals and optionally simple features like surface curvatures, we can highly constrain the initial 6 degrees of freedom search space of all relative transformations between two fragments. The suggested approach is robust, very time and memory efficient, easy to implement and applicable to all kinds of surface data where surface normals are available (e.g. range images, polygonal object representations, point clouds with neighbor connectivity, etc.).

2012

This paper, introduces a new approach for the automated reconstructionreassembly of fragmented objects having one surface near to plane, on the basis of the 3D representation of their constituent fragments. The whole process starts by 3D scanning of the available fragments. The obtained representations are properly processed so that they can be tested for possible matches. Next, four novel criteria are introduced, that lead to the determination of pairs of matching fragments. These criteria have been chosen so as the whole process imitates the instinctive reassembling method dedicated scholars apply. The first criterion exploits the volume of the gap between two properly placed fragments. The second one considers the fragments" overlapping in each possible matching position. Criteria 3, 4 employ principles from calculus of variations to obtain bounds for the area and the mean curvature of the contact surfaces and the length of contact curves, which must hold if the two fragments match. The method has been applied, with great success, both in the reconstruction of objects artificially broken by the authors and, most important, in the 2 virtual reassembling of parts of wall-paintings belonging to the Mycenaic civilization (c.1300 BC.), excavated highly fragmented in Tyrins, Greece.

British Machine Vision Conference, 2000

We describe here an efficient algorithm for re-assembling one or more un- known objects that have been broken or torn into a large number of ir- regular fragments—a problem that often arises in achaeology, art restora- tion, forensics, and other disciplines. The algorithm compares the curvature- encoded fragment outlines, using a modified dynamic programming sequence- matching algorithm, at progressively increasing

International Journal of Computer Vision, 2008

We propose a novel and efficient surface matching approach for reassembling broken solids as well as for matching assembly components using cluster trees of oriented points. The method rapidly scans through the space of all possible contact poses of the fragments to be (re)assembled using a tree search strategy, which neither relies on any surface features nor requires an initial solution. The new method first decomposes each point set into a binary tree structure using a hierarchical clustering algorithm. Subsequently the fragments are matched pairwise by descending the cluster trees simultaneously in a depth-first fashion. In contrast to the reassemblage of pottery and thin walled artifacts, this paper addresses the problem of matching broken 3D solids on the basis of their 2.5D fracture surfaces, which are assumed to be reasonable large. Our proposed contact area maximization is a powerful common basis for most surface matching tasks, which can be adapted to numerous special applications. The suggested approach is very robust and offers an outstanding efficiency.

1999

The problem of reconstruction of broken surface objects embedded in 3-D space is handled. A coordinate independent representation for the crack curves is developed. A new robust matching algorithm is proposed which serves for finding matching pieces even when some brittle pieces are missing. A prototype system having an X based GUI has been developed. This system generates artifical wire-frame data of broken pieces (with some noise) for a potshaped 3-D object and then recombines it using the proposed algorithms. 1 Introduction The handled problem appears heavily in field archeology where reconstruction of hollow objects becomes a tedious and laborious task. It is the problem of jigsaw puzzle assembling of 3-D surfaces with no texture or color hints provided. Previous work of [1, 2, 3] and the work of Wolfson [4] attack the 2-D problem and propose appropriate matching algorithms. Although Wolfson's algorithm is not the most efficient (O(n log n ffln)) it is especially well desig...

2011

IEEE Transactions on Pattern Analysis and Machine Intelligence, 2002

The problem of reassembling an object from its parts or fragments has never been addressed with a unified computational approach, which depends on the pure geometric form of the parts and not application-specific features. We propose a method for the automatic reconstruction of a model based on the geometry of its parts, which may be computer-generated models or range-scanned models. The matching process can benefit from any other external constraint imposed by the specific application.

IEEE Transactions on Pattern Analysis and Machine Intelligence, 2002

AbstractÐWe describe here an efficient procedure for reassembling unknown two-dimensional objects that have been broken or torn into a large number of irregular fragmentsÐa problem that often arises in archaeology, art restoration, forensics, and other disciplines. The procedure compares the curvature-encoded fragment outlines, at progressively increasing scales of resolution, using an incremental dynamic programming sequence-matching algorithm. The total cost gets reduced by a factor proportional to the mean number of samples per segment, which makes the method viable for problems of practical size (thousands of fragments). The performance of our method is illustrated with an artificial but realistic example.