3D geometrical modeling of excavation units at the archaeological site of Tell ‘Acharneh (Syria)

3D geometric modeling consists of representing geometric and spatial relationships of volumetric objects. We think it could be helpful in the context of archaeological excavation units representation and analysis. This article presents a procedure developed to generate 3D models from GPS positions taken at the top and the bottom of the excavation units boundaries on the archaeological site of Tell ‘Acharneh (Syria). It shows and discusses two geometrical modeling approaches (voxel and tetrahedral) used in the Gocad 3D modeling tool. Once excavation units are geometrically modeled, it is possible to refer them within a trench or the entire archaeological site, to handle them in various ways (zoom, rotation, translation), to perform on them 3D spatial analysis such as volumetric calculus or intersection computation, to make various kinds of queries such as to find out excavation units that have a certain number of artefacts, to generate sections anywhere in the 3D model, and finally to publish it with VRML (Virtual Reality Modular Language). As well as improving data analysis techniques, we think that if this 3D modeling operation can be done during the excavation, it could greatly help archaeologists to plan more efficiently their daily excavation strategy.     

Developing a documentation system for desert palaces in Jordan using 3D laser scanning and digital photogrammetry

Desert palaces in Jordan are unique pieces of art scattered in the desert as standing symbols of ancient civilizations. Due to their location, these palaces witness different environmental conditions which affect their status and sustainability. This raises the need to have a 3D documentation system reporting all spatial information for each palace, which can be used later for monitoring purposes. Digital photogrammetry is a generally accepted technique for the collection of 3D representations of the environment. For this reason, this image-based technique has been extensively used to produce high quality 3D models of heritage sites and historical buildings for documentation and presentation purposes. Additionally, terrestrial laser scanners are used, which directly measure 3D surface coordinates based on the run-time of reflected light pulses. These systems feature high data acquisition rates, good accuracy and high spatial data density. Despite the potential of each single approach, in our opinion, maximum benefit is to be expected by a combination of data from both digital cameras and terrestrial laser scanners. By these means the efficiency of data collection as well as the geometric accuracy and visual quality of the collected textured 3D models can be optimized. Within the paper, a 3D documentation system for Umayyad desert palaces in the Jordan desert will be presented using digital photogrammetry and laser scanning. The approach is demonstrated by generating high realistic 3D textured models for Amra and Kharanah palaces.     

3D reality-based artefact models for the management of archaeological sites using 3D Gis: a framework starting from the case study of the Pompeii Archaeological area

This work describes the procedures, the different techniques and the pipeline used for creating a digital framework that should assist the Superintendence of Pompeii in the digital reconstruction, classification, management and visualisation of archaeological finds inside an advanced 3D web-based repository of reality-based data. Specific topics have been focused on the quality assessment procedures adopted to ensure consistency and reliability of data throughout the whole 3D models acquisition and pipeline creation, as well as on the particular semantic reality-based structure adopted to develop an information system into a knowledge one. The main purposes of our framework have been the usage of 3D digital models as a restitution of the real object and as a metaphor for navigating through the data; 3D models were used as archaeological cognitive systems and developed as a collection of structured objects, identified through a precise terminology that allows to easily extend the concept of 2D GIS to 3D GIS. In addition, the system was developed as a scalable application that allows the use of the same database by different users, simply filtering the data according to the specific requirements, and can operate both as standalone and web-based application.     

3D modelling of magnetic data from an archaeological site in north-western Tlaxcala state,Mexico

In Archaeology, geophysical methods had been applied usually in a qualitative form, limited only to the use of filters that enhance the data display. The main objective in this work is the implementation of a modelling technique that allows us to reconstruct the geometry of buried bodies and the determination of their depths. This is done by means of the estimation of the magnetic moments of archaeological objects using a three-dimensional mesh of individual magnetic dipoles using the least squares method and the singular value decomposition of a weighted matrix to solve the linear problem. The distribution and shape of the underlying archaeological remains can be inferred. This methodology was applied to an archaeological site called Los Teteles de Ocotitla, in the state of Tlaxcala, Mexico. A high-resolution magnetic prospection was carried out in three selected areas (terraces). The most important total field anomalies found on each area were inverted, obtaining results that were corroborated by archaeological excavations. This investigation demonstrates the potential of quantitative geophysical methods for the characterization of archaeological structures, in extension and in depth.     

A simple methodology for recording petroglyphs using low-cost digital image correlation photogrammetry and consumer-grade digital cameras

In the present study a simple method is described for obtaining 3D digital models of petroglyphs of different sizes and characteristics and its usefulness, in the study of this cultural heritage, is evaluated. For this research we used low-cost photogrammetric software and consumer-grade digital cameras, without any other surveying techniques. In order to test this methodology, three field research studies were carried out in Galicia (Spain).     

Structured light scanning for high-resolution documentation of in situ archaeological finds

Archaeologists strive to document the process of excavation and discovery as completely as possible. Over the past several decades archaeologists have incorporated a growing number of computerized techniques for documenting archaeological finds. Scanning is one such technique. There are a number of technologies that now allow archaeologists to scan structures, excavation surfaces and in situ artifacts to create high-resolution, 3D data sets. We report here on a trial application of one of these, a structured-light scanner, to create 3D representations of excavated surfaces and associated artifacts at two Middle Paleolithic sites in southwest France. In each instance, surfaces of approximately 2.5 m² were scanned in approximately 1 day. The resulting data sets are very good representations of the originals in terms of colors and spatial details, and as such provided an important piece of archaeological documentation. To use this equipment successfully in the field, however, required solving a number of logistical issues, and the amount of time required to learn to use this equipment was significant. Once these issues are addressed, this technology is appropriate for documenting extraordinary, unique finds where time and costs are offset by the importance of good documentation.     

Investigation of past archaeological landscapes using remote sensing and GIS: a multi-method case study from Mount Ida,Crete

Spatial analysis in geoarchaeological applications can be improved by implementing a wider set of geoecological parameters, in order to provide more precise results. The aim of the paper is to show how geoscientific ground-truth and techniques can be adopted for detailed archaeological studies using a comprehensive set of environmental variables that might have influenced ancient settlement patterns. The project focuses on spatial patterns of archaeological sites as well as Bronze Age communication paths in Central Crete by applying a multi-method approach (surveying, remote sensing, DEM analysis, least-cost analysis, candidate site detection, predictive modelling, etc.). In contrast to conventional archaeological GIS applications this enhanced strategy offers promising prospects regarding landscape and settlement modelling.     

3D model of the Can Sadurní cave

Graphic and metric information about the site and its environment and about the different structures and artefacts located are indispensable for the optimal management of an archaeological excavation. A Geographic Information System (GIS) proves useful in managing and analysing information and data obtained from different sources. Two techniques of data capture, Terrestrial Laser Scanning (TLS) and close range photogrammetry, are used to generate accurate and high-resolution 3D models of a cave, the silos and a combustion structure at the Can Sadurní site (Begues, NE Spain). This site is especially noteworthy on account of its complete stratigraphy of the Catalonian Holocene. The capture and processing of the photogrammetric and TLS data used to generate 3D models are discussed in detail. These models cannot be obtained by classic archaeological techniques since the record is made layer by layer, approximately one decimetre apart, with the result that the information between the layers is lost. Our findings highlight the potential of these techniques for obtaining accurate and photorealistic models that facilitate a complete analysis of the available information at an archaeological site.     

Virtual skeletons: using a structured light scanner to create a 3D faunal comparative collection

Appropriate comparative animal skeletons are not always available to faunal analysts for use in identifying archaeofaunal remains. This is especially pertinent when working in locations where no comparative collections are available locally, and the archaeological assemblage cannot be transported to another facility. In order to fill this gap, we are building a virtual comparative faunal collection using a structured light scanner to scan modern skeletal material in 3D. The resulting high resolution 3D color models are a valuable resource for identifying fossil specimens. Scan data can be converted into a variety of formats for viewing and can be transported on a portable digital device for use at field or laboratory localities. In addition, scans can be printed three dimensionally to produce a replica of the scanned skeletal part. A particular advantage of this digital technology is that we can eventually create a complete 3D representation of a taxon's skeleton from scans of several components of what are incomplete skeletons of one animal taxon in a museum collection. The results of our project thus far are available to other researchers and educators by means of the internet. A variety of interested parties could benefit from such a collection, including zooarchaeologists, paleontologists, biologists, teachers and museum curators.     

Imaging the invisible using modified digital still cameras for straightforward and low-cost archaeological near-infrared photography

Analogue near-infrared (NIR) photography has already been used a lot in both scientific and medical photography, in which cases near-infrared (NIR) radiation was mostly captured by InfraRed (IR) sensitive plates or film emulsions. However, its use in archaeology has remained rather restricted, most likely due to some ignorance and/or lack of knowledge about this kind of photography, while the critical imaging process also severely limited its use. This situation could be, however, changed completely, as the image sensors used in digital still cameras (DSCs) are very sensitive to NIR wavelengths, making the quite lengthy and error-prone film-based NIR imaging process obsolete. Moreover, modifying off-the-shelf DSCs even simplifies this digital acquisition of NIR photographs to a very large extent.By starting with a general outline of the ElectroMagnetic (EM) spectrum and the specificities of NIR radiation, the base is laid out to tackle the possibilities and practicalities of archaeological NIR imaging, subsequently comparing the earlier film-based approach with the digital way of NIR shooting, showing how the latter can greatly benefit from modified compact, hybrid and small-format Single Lens Reflex (SLR) DSCs. Besides in-depth information on the technique of digital NIR photography, examples will illustrate its archaeological potential.     

From Hand Survey to 3D Laser Scanning: A Discussion for Non-Technical Users of Heritage Documentation

Abstract

Digital technology has changed our approaches to cultural heritage documentation radically and promises to continue to bring rapid changes. Photographic and non-photographic (graphic) documentation tools are merging in one process, in which digital photographic technology is the main base. Due to digital technology, there is an increasing gap between specialist technicians and non-technical users involved in heritage documentation. 3D approaches are still not popular among users in cultural heritage. However, in order to build a bridge between the specialist and non-technical users, a dialogue between them needs to be developed, not only to discuss issues of data precision and 3D accuracy, but also visualization production systems, which can now easily be achieved by modern digital photographic technology.

This paper presents a comparative evaluation and synthesis of cultural heritage documentation methods and survey techniques currently available, focusing on the needs and requirements of non-technical users of heritage documentation. It attempts to clarify some new aspects in cultural heritage documentation and to assess the impact of current technology. The paper undertakes a comparative evaluation of the potential application of digital methods in documentation — and examines issues such as quality, accuracy, time, costs and specific skills required — from pre-electronic techniques (hand measurement) to 3D laser scanning, which today represents the most advanced technology available for measuring and documenting objects, structures and landscapes.     

A GIS method for assessing the zone of human-environmental impact around archaeological sites: a test case from the Late Neolithic of Wadi Ziqlâb,Jordan

Assessing the impact of prehistoric sites on their local environment is difficult to accomplish with standard archaeological methods. Simulation modeling offers a solution to this issue, but it is first necessary to delimit a site catchment, or “zone of impact”, around archaeological sites in which to carry out human–environment interaction modeling. To that end, I have developed a new method for GIS-based catchment reconstruction and distilled it into a custom module (r.catchment) for GRASS GIS, which calculates catchments of a given area based on anisotropic travel costs from a point of origin. One method of applying this new module in exploratory catchment modeling is discussed using the pastoral economy of the Late Neolithic period in Wadi Ziqlâb, Northern Jordan as a test case. A model of Late Neolithic herding economy and ecology is constructed, which combines data from archaeology, phytogeography, range science, agronomy, and ethnohistory. Four sizes of pastoral catchments are then derived using r.catchment, and the herd ecology model is used to estimate the stocking-rate (carrying capacity) of mixed goat and sheep herds for each catchment. The human populations these herd numbers could support (between 3 and 630 people in the Wadi) are then compared with human population estimates derived from household architectural analyses (between 18 and 54 people in the Wadi) to determine the most probable catchment configurations. The results indicate that the most probable zone of impact around the known Late Neolithic sites in Wadi Ziqlâb was somewhere between 9 and 20 square kilometers, delineated by 3 and 4.5 km pasture radii respectively.     

Performance evaluation of a multi-image 3D reconstruction software on a low-feature artefact

Nowadays, multi-image 3D reconstruction is an active research field and a number of commercial and free software tools have been already made available to the public. These provide methods for the 3D reconstruction of real world objects by matching feature points and retrieving depth information from a set of unordered digital images. This is achieved by exploiting computer vision algorithms such as Structure-From-Motion (SFM) and Dense Multi-View 3D Reconstruction (DMVR). In this work, we evaluate the performance of a low-cost commercial SFM–DMVR software by digitising a Cycladic woman figurine. Although the surface properties of the specific artefact are considered 3D laser scanner friendly, its almost featureless white-grey surface composes a challenging digitisation candidate for image based methodologies as no strong feature points are available. We quantify the quality of the 3D data produced by the SFM–DMVR software in relation to the data produced by a high accuracy 3D laser scanner in terms of surface deviation and topological errors. We question the applicability and efficiency of two digitisation pipelines (SFM–DMVR and laser scanner) in relation to hardware requirements, background knowledge and man-hours. This is achieved by producing a complete 3D digital replica of the Cycladic artefact by following both pipelines.     

The Tel Akko Total Archaeology Project (Akko,Israel): Assessing the suitability of multi-scale 3D field recording in archaeology

Abstract

Archaeology is a destructive discipline, and, unfortunately, the majority of methods employed by archaeologists to record and preserve the archaeological record consist of two-dimensional representations of three-dimensional (3D) subjects. Recent breakthroughs in 3D technology, however, have the potential to revolutionize the discipline. In recent years, multiple software suites capable of generating spatially accurate, photorealistic 3D models with a series of digital photographs have become available. Following a successful season of field testing in 2011, the Tel Akko Total Archaeology Project (Akko, Israel) expanded the use of Agisoft’s PhotoScan Pro—one of the commercially available software suites—to test the accuracy and suitability of the program for archaeological applications at multiple scales. After two years of field testing, it is clear that the implementation of PhotoScan Pro in archaeology facilitates unprecedented accuracy in field recording and digital heritage management, and provides a new outlet for the dissemination of archaeological data.     

Estimating original flake mass from 3D scans of platform area

This study confirms the increased capacity to predict flake mass that arises from more accurately measuring surface area in three dimensions using a digital scanner. We also reveal the existence of significantly different relationships between platform area and flake mass for flakes with different platform types and ventral and dorsal morphologies. These different relationships between platform surface area and mass have not been previously identified, and reveal the complexity of platform/mass relationships. Using multivariate regression of 3D platform surface area and external platform angle we improve the accuracy of predictions of original flake mass. We propose a method for studying reduction intensity on retouched flakes, based on comparing predictions of the initial mass of the flake with measurements of the mass following retouching to estimate the amount of mass removed through retouching. We name this approach the Initial-/Terminal-Mass Comparison, or ITMC. Our experiments demonstrate that the capacity of the 3D platform scans to predict flake mass, and by implication the capacity of the ITMC to estimate mass loss, rivals or exceeds the capacity demonstrated for existing reduction measures.     

Latest developments in rock art recording: towards an integral documentation of Levantine rock art sites combining 2D and 3D recording techniques

This paper presents a further step in the integral documentation of prehistoric rock art, combining 2D and 3D digital recording techniques. Image processing and digital enhancement techniques are an invaluable aid to obtain high quality and accurate 2D recordings, especially when working with faint motifs or complex superimpositions. But what constitutes a real breakthrough is the possibility of combining 2D digital tracings with metric 3D models, providing a whole set of metric outputs that improve our understanding of the motifs in their context and, at the same time, can be used to deliver accurate metric reproductions.     

ASSESSING WHAT LIES BENEATH THE SPATIAL DISTRIBUTION OF A ZOOARCHAEOLOGICAL RECORD: THE USE OF GIS AND SPATIAL CORRELATIONS AT EL MIRÓN CAVE (SPAIN)*

Geographical Information Systems (GIS) are being incorporated into archaeology as a technique to improve the understanding of spatial organization and the relationships among finds within specific areas. Although their use as a basic tool in predicting the location of archaeological sites or in assessing the extent of their catchment areas is relatively common, in general, they have less often been applied to the study of the spatial distribution of archaeological remains within individual deposits, and in particular to faunal assemblages. Despite this, they can prove essential to understanding dispersion and grouping patterns within deposits fully, and, together with various correlation analytical techniques, they provide valuable information about the economic organization of settlements and inhabitant lifeways. To demonstrate the potential of this methodology, a zooarchaeological GIS has been prepared for the Middle and Late Magdalenian and Azilian layers in El Mirón Cave (eastern Cantabria, Spain), and the spatial distribution patterns of various attributes of the archaeological record have been analysed. Significant conclusions in terms of type and duration of human occupation have been drawn.     

3D Digital Documentation,Assessment, and Damage Quantifi cation of the Al-Deir Monument in the Ancient City of Petra,Jordan

Abstract

The rock-cut monuments in the ancient city of Petra in Jordan form an outstanding tangible heritage site. Unfortunately, this important part of the world's cultural heritage is gradually being diminished due to weathering and erosion problems. In this research, an approach combining in situ surveying and laboratory analysis is applied in order to provide sufficient and comprehensive data regarding the documentation and evaluation of the status of the Al-Deir monument in Petra. The purpose was not only to quantify the damage, but also to make a first step towards creating a 3D monitoring programme of the deterioration rate. The approach presents a correlation study between the environmental condition and the surface weathering damage, using 2D mapping of the weathering form and accurate 3D realistic modelling from laser scanning and digital photogrammetry. The 2D mapping provides detailed weathering damage information for the entire stone surface of the monument, whereas the 3D modelling provides information on the spatial distribution and texture of the damage. Additionally, the 3D digital model can provide reference data as an exact guide to the restoration needed. In order to support the visual presentation of 3D surface details, a hybrid approach combining data from laser scanning and digital imagery was developed.

Studies of stone texture and spatial distribution of soluble salts were carried out at the monument in order to explain the mechanism of the weathering problem. Relative humidity, temperature, and wind are the main factors in the salt damage process. In order to study the effect of these conditions in the salt crystallization process a series of fieldwork investigations and laboratory work were undertaken. The results show that visible zoning of weathering damage is correlated to different salt concentrations.     

Using 3D scanning in the investigation of Upper Palaeolithic engravings: first results of a pilot study

This paper deals with the reinvestigation of selected engravings on slate plaquettes from the Late Upper Palaeolithic site of Gönnersdorf, Germany, by applying new 3D scanning methods for the first time. The aim of this method is to obtain further information about stylistic aspects of the depictions as well as to identify an inner chronology and interrelationship of the lines. In addition new options of 3D photography are tested as a further visual support of investigation and documentation. Previously analyses were subjective whereas the new interpretation uses impartial metric methods. In the future the more objective results will allow the comparison of engravings and their details, with the aim of discerning different artists as well as obtaining a better understanding of the art of former hunter- gatherer societies.