Abstract

An automatic reconstruction of ancient artifact fragments is of great interest in archaeology, and is considered important because it helps archaeologists make inferences about past cultures and civilizations. Therefore, numerous researches proposed various methods to put together and restore the fragments of a piece of pottery to its original form. The aim of this paper is to present an in-depth review of the most important available publications in computer applications related to the area of the classifying and reconstruction of three-dimensional model for archaeological pottery objects over the epoch in the early eighties until the end of 2013. This task classified according to the feature extraction, the classification process and the matching techniques implemented for the purpose of restoration of the fragments of pottery object to its original form. Moreover, this paper focused on review and analyze the results that they have achieved.


1- INTRODUCTION

Archaeology is the scientific study of the last remnants of humanitarian civilization, which means exploring the lives of ancient peoples by examining their waste, and discovering human activity in the past through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture and cultural landscapes. Incidentally, it should be mentioned that the area of ceramics is one of the most common in archaeology in terms of ancient fragments (Kampel & Sablatnig 2004). Hence, the reconstruction of unknown objects from a large number of smaller pieces may involve thousands of irregular fragments, and is a tedious task, especially in case of the loss some pieces. It sometimes requires laborious effort, and may take years of tedious work and may involve a great number of laborers and experienced archaeologists. The laborers and archaeologists involved must deal with the artifacts cautiously to avoid further damage, especially with the edges of fragments, when they attempt to assemble the fragments manually, because assemble the fragments are similar to assemble the pieces of a jigsaw puzzle (Casta?eda et al. 2011; Funkhouser et al. 2011). Numerous archaeologists challenged the task of achieving the accurate reassembly of the archaeological fragments and returning them to their original form because of the high value in information that represents past civilizations and cultures. This paper will carry out a review to the studies that were performed using computers to retrieval archaeological excavation fragments into their original form. The main objective of the review of previous studies is to facilitate the task of subsequent studies by proposing new algorithms in order to achieve better results than the previous algorithms.
This paper is structured into several sections. An overview of the reconstruction of fragmented objects is presented in Section 2, the structure search is drawn in Section 3, and Section 4 provides studies performed during the period eighties until the end of 2013. An important analysis is presented in Section 5. Finally, Section 6 summarizes and highlights the most important conclusions.


2- Reconstruction of Fragmented Objects

The world has witnessed great development in the performance of computers as the use of image processing and pattern recognition techniques, which encouraged researchers to attempt to solve the problem of reconstruction of fractured objects from a large collection of randomly mixed fragments via proposed systems instead of manually assembling them, which is a tedious and time consuming task. To overcome this problem, several authors have worked on the automated reconstruction of fragmented objects, and the core concept of this problem is finding a solution for many applications. One application is reconstructing torn documents (Richter et al. 2011; Lin & Chiang 2012) that are assembled for the purpose of extracting the text in the torn documents, which it is an important process in the field of forensics.
Another application is the restoration of the fragments of archaeological objects, specifically ceramic and pottery fragments, which has been presented by several researchers (Leitao & Stolfi 2005; Smith et al. 2010; Oxholm & Nishino 2012) who were interested to find the solutions to broken fragmented pottery. Furthermore, numerous researchers (Toler-Franklin et al. 2010; Shin et al. 2010; 2012) have worked on the reconstruction historical wall paintings, which are usually scattered into many hundreds or even thousands of fragments, located in many sites, such as the seventeenth century BC fragmented wall paintings, excavated in Akrotiri, Santorini, Greece. In terms of the restoration of broken glass plates, the study carried out by Stanco et al. (2011) about the virtual restoration of the fragments of glass plate photographs of archaeological repertoires. This study focused on the methods that aimed to reconstruct the fragments of ancient pottery artifacts.

3- The Structure Search

In order to review previous studies, this paper concentrates on matching and reconstructing three-dimensional of historical pottery fragments. It divides the previous studies into four groups according to the period that the study has been prepared. For each group, all studies are classified based on the extracted features, the classification technique that was used, and the results achieved, as shown in Figure 1.