Documenting carved stones from 3D models

Paper on the documentation of carved stones was published in the Journal of Cultural Heritages.

Abstract: Revealing carved parts in rock art is of primary importance and remains a major challenge for archaeo-logical documentation. Computational geometry applied to 3D imaging provides a unique opportunity todocument rock art. This study evaluates five algorithms and derivatives used to compute ambient occlu-sion and sky visibility on 3D models of Mongolian stelae, also known as deer stones. By contrast withthe previous companion work, models are processed directly in 3D, without preliminary projection. Vol-umetric obscurance gives the best results for the identification of carved figures. The effects of modelresolution and parameters specific to ambient occlusion are then evaluated. Keeping tridimensionalinformation intact allows accurate measurement of distance, volume, and depth. Objects augmentedby ambient occlusion can easily be manipulated in 3D viewers, for seamless and effortless access tothe overall organization of the figures, at the scale of the entire object. Qualitatively speaking, the 2D projected outputs are equivalent to, or even better than, existing archaeological documentation. Theproposed workflow should be easily applicable in many situations, particularly as the functions providedfor the free R programming software are fully configurable.

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A computer tool to identify best matches for pottery fragments

Paper on the semi-automatic classification of pottery fragments was published in the Journal of Archaeological Science: Reports.

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Abstract: Archaeologists working with pottery spend a considerable amount of time on a fundamental task – providing precise descriptions of pottery fragments. This study presents a survey of existing computational solutions to identify the best matches for a given fragment, based on its shape. Four methods (ICP, DCT, RDP, and RTC) are compared, using a pottery dataset from Graufesenque (southern France), dated to the Roman Period. The first three methods produced successful and very similar results for rim fragments (within the five best candidates for 95% of the dataset). The ICP algorithm produced the best overall results for rim fragments, and can also be used for non-rim fragments. A practical computer application, including all the above methods, was developed in R programming language, with an easy-to-use graphical interface, and is now made freely available to the archaeological community for future studies, and further development.

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3D scanning and modelling in archaeology

Presentations for the course of “3D scanning and modelling in archaeology” which will be held this spring at the University of Hradec Kralove have been added to teaching materials.

The aim of the course is to present basic methods, principles and devices used for 3D acquisition of archaeological artefacts and ecofacts. The course will consist of both theoretical and practical parts. The theoretical part will focus on a brief presentation of 3D acquisition methods (e.g. laser triangulation scanners, structured light, computed tomography, photogrammetry). The practical part will consist of scanning of real-world artefacts.

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DACORD updated

The DACORD application, originally published in Journal on Computing and Cultural Heritage, has been updated. The recent version is available here. The original version of the application, along with the article can be found on the official pages of ACM (link).

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Course “Iron Age in Europe” at the Departement of archaeology UHK

The new course – Iron Age in Europe – an extension to one given by Tomáš Mangel, will take place at the Departement of archaeology at the University of Hradec Králové in spring 2019.

The aim of this course is to present and discuss new discoveries and current research topics in the Iron Age archaeology in the European context. Students will be introduced into the issues linked with the emergence of European archaeological/cultural entities, throughout their social and economic development and long-distance relations, until their final destabilisation and/or transformations. The main part of the course will deal with issues linked with the complexity and biases of existing methodological approaches of funerary and settlement areas and will point out to some new methodologies and perspectives of their application for the modern archaeological inquiries. This theoretical background will be complemented by the presentation of several recent case-studies intended to investigate the problematics.

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Course “Statistics and geometric morphometrics” at the Departement of archaeology UHK

The new course – Modern quantitative methods and shape analysis in archaeology – will take place at the Departement of archaeology at the University of Hradec Králové in spring 2019 and 2020.

cours_morphometrics.PNGThe aim of the course is to apprehend to quantitatively express and process the information about the shape of archaeological artefacts. Students will be familiarised with the traditional and modern geometric morphometrics methods (2D/3D landmark analysis, analyses of open or closed contours, etc.). An essential part of the course will be devoted to the recent shape acquisition techniques (3D scanning, photogrammetry, etc.), followed the statistical treatment of the morphometric data. At the end of the course, students should be able to choose an appropriate method to solve variety of archaeological questions concerning various artefact productions (stone, ceramic, metal), dated to diverse chronological periods.

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DACORD published

A paper named Computer-Assisted Orientation and Drawing of Archaeological Pottery, written by Wilczek, J., Monna, F., Jébrane, A., Labruère Chazal, C., Navarro, N., Couette, S. and Chateau, C., whose aim is to simplify the routine work of ceramic documentation has been recently published in Journal on Computing and Cultural Heritage.

ceram3.PNGArchaeologists spend considerable time orienting and drawing ceramic fragments by hand for documentation, to infer their manufacture, the nature of the discovery site and its chronology, and to develop hypotheses about commercial and cultural exchanges, social organisation, resource exploitation, and taphonomic processes. This study presents a survey of existing solutions to the time-consuming problem of orienting and drawing pottery fragments. Orientation is based on the 3D geometry of pottery models, which can now be acquired in minutes with low-cost 3D scanners. Several methods are presented: they are based on normal vectors, or circle fittings, or profile fittings. All these methods seek to determine the optimal position of the rotation axis. We also present and discuss new approaches and improvements to existing methods. We have developed a suite of functions for the computer-assisted orientation and drawing of archaeological pottery. The profile and contours of the fragment, as well as any possible decoration, can be depicted in various ways: photorealistic rendering or dotted patterns, calculated by ambient occlusion, combined or not with artificial light. The general workflow, evaluated using both synthetic and real-world fragments, is rapid, accurate, and reproducible. It drastically reduces the amount of routine work required to document ceramic artefacts. The information produced, together with the 3D representation of the fragments, can easily be archived and/or exchanged within the archaeological community for further research. The source code (built in the R environment), together with an installation notice and examples, is freely downloadable.

See here for more information.