My main interest is in integration of imaging technologies into different research tools and applications, as well as using it for dissemination and sharing of research data.
The main focus of my thesis was on Web visualization technologies that could be applied to visualize archaeological textile data.
Currently I co-run small company called Archaeovison (http://archaeovision.eu) and non-profit, more research oriented, Archaeovision R&D. We are focussed on documentation, archiving and dissemination issues in cultural heritage sector. Supervisors: Graeme Earl
Computational Approaches to Archaeological Spaces, 2016
This volume of original chapters written by experts in the field offers a snapshot of how histori... more This volume of original chapters written by experts in the field offers a snapshot of how historical built spaces, past cultural landscapes, and archaeological distributions are currently being explored through computational social science. It focuses on the continuing importance of spatial and spatio-temporal pattern recognition in the archaeological record, considers more wholly model-based approaches that fix ideas and build theory, and addresses those applications where situated human experience and perception are a core interest. Reflecting the changes in computational technology over the past decade, the authors bring in examples from historic and prehistoric sites in Europe, Asia, and the Americas to demonstrate the variety of applications available to the contemporary researcher.
International Journal of Heritage in the Digital Era, 2012
This paper describes on-going research investigating movement and behaviour patterns of visitors ... more This paper describes on-going research investigating movement and behaviour patterns of visitors in archaeological sites as a way of informing interpretive planning. A critical point of this study was the development of a hybrid methodology for collecting and assessing data on visitor movement around archaeological sites and of the things that visitors value the most during their visit. This paper demonstrates the methodology developed mainly at Gournia, a Minoan archaeological site of eastern Crete in Greece. Apart from recognised forms of observation and the collection of qualitative data, technologies such as Geographical Positioning System body tracking, geo-tagging and applications of Geographical Information Systems were employed. The interpretation of the processed data provided a better insight and an overview of the site's affordances for movement and as well as the weaknesses of the current interpretation infrastructure. Additionally, the methodology extends to a visit...
To compare intermittent treatment (IT) versus continuous treatment (CT) using cyproterone acetate... more To compare intermittent treatment (IT) versus continuous treatment (CT) using cyproterone acetate (CPA) in bone metastatic prostate cancer patients, we conducted an open-label, multicenter randomized trial. Continuous androgen deprivation therapy is the standard treatment in metastatic prostate cancer. Intermittent treatment might maintain efficacy while toxicity and costs are reduced. Patients received CPA 100 mg tid in the prephase. Patients with a PSA decline of ≥ 90 % or PSA <4 ng/ml were randomized. If patients were progressive, LHRH analogues were added. Primary end point was time to PSA progression. A total of 366 patients were recruited; 258 reached a good response after 3 or 6 months and were randomized. A total of 131 patients randomized to IT and 127 to CT. Patients on IT had an average of 1.7 episodes on CPA, before LHRH analogues were started. The mean time without treatment in IT was 463 days versus 422 days on treatment. There were statistical significant differences between IT and CT in 3 of the 5 functional scales of EORTC QLQ C 30; however, the clinical relevance of this finding appears modest. Symptom and potency scales showed significant advantages for IT. There were no differences in time to PSA progression on CPA, time to PSA and/or clinical progression on LHRH analogues and time to cancer-specific and overall survival. IT by CPA is associated with less symptoms and modest advantages in QOL domains. There were no differences in time to PSA progression, clinical progression or survival.
A digital survey, combining photogrammetry and reflectance transformation imaging (RTI), offers s... more A digital survey, combining photogrammetry and reflectance transformation imaging (RTI), offers significant new insights into the British Museum's Easter Island statue called Hoa Hakananai'a. These include the likelihood that it was made with a tapering base to stand in the ground, as seen by the crew of HMS Topaze in 1868, and that a nearby stone described a century ago was a pukau, a stone ‘hat’. Petroglyphs consisting of two komari (stylised female genitalia) were subsequently added. Succeeding these were bas-relief carvings, here interpreted as a single composition that narrates the island's birdman myth as recorded in the nineteenth and early twentieth centuries. This reading is supported by photographs of Hoa Hakananai'a taken in Chile in 1868. A new model is presented for the relationship between the statue and the birdman cult. As it now stands, in a nineteenth-century plinth, Hoa Hakananai'a appears to lean slightly from its intended placing.
ABSTRACT This tutorial summarises our uses of reflectance transformation imaging in archaeologica... more ABSTRACT This tutorial summarises our uses of reflectance transformation imaging in archaeological contexts. It introduces the UK AHRC funded project reflectance Transformation Imaging for Anciant Documentary Artefacts and demonstrates imaging methodologies.
New methods of visualisation offer the potential for a more detailed record of archaeological obj... more New methods of visualisation offer the potential for a more detailed record of archaeological objects and the ability to create virtual 3D models that can be made widely available online. Here, two different techniques are applied to the impressive Easter Island statue on display in the Wellcome Gallery at the British Museum. Of particular importance are the details revealed of the petroglyphs that decorate its surface.
Introduction Digital archaeological analyses of space have proceeded traditionally from two disti... more Introduction Digital archaeological analyses of space have proceeded traditionally from two distinct perspectives. First, there has been a phenomenological appraisal of computer graphic modelled geometry, and second a formal analysis of the surviving spaces and extrapolations from them. The former approach encompasses work on the visualisation of raw geometric data captured through techniques such as laser scanning and photogrammetry. In addition it has considered to be significant the process and interfaces within which extrapolations from these data take place – namely the construction of increasingly sophisticated graphical simulations in software such as 3ds Max, Maya and Vue Infinite. Finally, it draws upon the ability of such software and interactive visualisation tools to stimulate new interpretations through interaction with the visualised geometry. This virtual phenomenology in turn has been seen to be significantly enhanced by an emphasis on physical realism (Chalmers 2002...
This full day tutorial will use lectures and demonstrations from leading researchers and museum p... more This full day tutorial will use lectures and demonstrations from leading researchers and museum practitioners to present the principles and practices for robust photography-based digital techniques in museum contexts. The tutorial will present many examples of existing and cutting-edge uses of photography-based imaging including Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR), camera calibration, and methods of imaged-based generation of textured 3D geometry. The tutorial will also explore a framework for Leading museums are now adopting the more mature members of this family of robust digital imaging practices. These practices are part of the emerging science known as Computational Photography (CP). The imaging family’s common feature is the purpose-driven selective extraction of information from sequences of standard digital photographs. The information is extracted from the photographic sequences by computer algorithms. The extracted information is then integ...
This paper will consider the possibilities for the use of Reflectance Transformation Imaging (RTI... more This paper will consider the possibilities for the use of Reflectance Transformation Imaging (RTI) and specifically Polynomial Texture Mapping (PTM) in the simulation of archaeologically derived materials. PTM was designed to enable complex surface shading of simulated textures, as an enhancement to bump mapping. However, whilst PTM and RTI files cannot be included in the rendering pipeline of standard tools such as Mental Ray we discuss in this paper the opportunities for repurposing RTI data in visualisation work. RTI is unique in allowing for the capture of a high resolution, highly versatile surface record whilst utilising commonly available, highly affordable equipment and software. Consequently RTI has become increasingly ubiquitous as a method for archaeological recording and a large and growing body of data exists. This paper will present some of the techniques which have been developed at the archaeological Computing Research Group at the University of Southampton which all...
Research institutions, funding bodies and researchers themselves are becoming increasingly aware ... more Research institutions, funding bodies and researchers themselves are becoming increasingly aware of the need to manage imaging and 3D data. At an institutional level data management policies are playing an increasingly significant role laying down plans for the provision of infrastructure, policy and guidance. Drawing upon the preliminary results of the University of Southampton’s JISC funded DataPool project, this paper will gauge the extent to which institutional policy development might be supplemented or even enhanced by an increased awareness of localised responses to the challenges of imaging and 3D data management. The paper will review approaches to data management that have been adopted by individuals and research groups and will propose that in many cases these developments might be pivotal in defining the form of institutional data management policy should take
Several thousand incised graffiti adorn the sandstone walls of the Great Enclosure at Musawwarat ... more Several thousand incised graffiti adorn the sandstone walls of the Great Enclosure at Musawwarat es Sufra (Sudan), a unique sacral building complex dating to the Meroitic period (c. 270BC-AD350) of the Kingdom of Kush. The often finely incised informal inscriptions and images – rare evidence of non-official art and ritual practice – are threatened by accelerated weathering and the negative side effects of increased tourism. Several past attempts at documenting the hitherto unpublished graffiti corpus have been hampered by limitations inherent in traditional photographic and other graphic recording techniques. In 2009 white light scanning was tested on some graffiti with good results, but its high cost and the loss of important colour information limited its application. In 2011 low-cost Reflectance Transformation Imaging (RTI), which captures surface details in different lighting conditions, was tested on a large sample of graffiti. RTI is based on traditional raking light photograp...
Polynomial Texture Mapping (PTM; Malzbender et al 2001) uses multiple images to capture the refle... more Polynomial Texture Mapping (PTM; Malzbender et al 2001) uses multiple images to capture the reflectance properties of a given surface. Multiple captures may be combined in order to produce interactive, relit records of the material recorded. In addition recent research enables the capture and rendition of interactive PTMs for detailed examination of surface details. Cultural heritage examples of the technology include work on Cuneiform tablets, numismatic archives and lithic artefacts. This paper will describe the PTM data capture and processing technologies developed by the University of Southampton, with support from Hewlett Packard Labs Palo Alto. It will also identify the perceived archaeological potential of additional recording to supplement the standard PTM datasets, including the recording of the surface BRDF (bi-directional reflectance distribution function) and accurate extraction of surface normals. Such data offer considerable, under-exploited value in production of comp...
Reflectance Transformation Imaging (RTI) is a technology that uses conventional digital photograp... more Reflectance Transformation Imaging (RTI) is a technology that uses conventional digital photographs to derive detailed surface shape information (Figure 1). It is a digital, interactive version of the raking light photography commonly used in finds photography and (with the sun) on site to represent subtle changes in surface morphology. The University of Southampton is currently leading a project in collaboration with Oxford University funded by the AHRC further to develop and promote the RTI technology. We recently provided a demonstration of the available tools at the IfA conference on April 11th 2011.
Computational Approaches to Archaeological Spaces, 2016
This volume of original chapters written by experts in the field offers a snapshot of how histori... more This volume of original chapters written by experts in the field offers a snapshot of how historical built spaces, past cultural landscapes, and archaeological distributions are currently being explored through computational social science. It focuses on the continuing importance of spatial and spatio-temporal pattern recognition in the archaeological record, considers more wholly model-based approaches that fix ideas and build theory, and addresses those applications where situated human experience and perception are a core interest. Reflecting the changes in computational technology over the past decade, the authors bring in examples from historic and prehistoric sites in Europe, Asia, and the Americas to demonstrate the variety of applications available to the contemporary researcher.
International Journal of Heritage in the Digital Era, 2012
This paper describes on-going research investigating movement and behaviour patterns of visitors ... more This paper describes on-going research investigating movement and behaviour patterns of visitors in archaeological sites as a way of informing interpretive planning. A critical point of this study was the development of a hybrid methodology for collecting and assessing data on visitor movement around archaeological sites and of the things that visitors value the most during their visit. This paper demonstrates the methodology developed mainly at Gournia, a Minoan archaeological site of eastern Crete in Greece. Apart from recognised forms of observation and the collection of qualitative data, technologies such as Geographical Positioning System body tracking, geo-tagging and applications of Geographical Information Systems were employed. The interpretation of the processed data provided a better insight and an overview of the site's affordances for movement and as well as the weaknesses of the current interpretation infrastructure. Additionally, the methodology extends to a visit...
To compare intermittent treatment (IT) versus continuous treatment (CT) using cyproterone acetate... more To compare intermittent treatment (IT) versus continuous treatment (CT) using cyproterone acetate (CPA) in bone metastatic prostate cancer patients, we conducted an open-label, multicenter randomized trial. Continuous androgen deprivation therapy is the standard treatment in metastatic prostate cancer. Intermittent treatment might maintain efficacy while toxicity and costs are reduced. Patients received CPA 100 mg tid in the prephase. Patients with a PSA decline of ≥ 90 % or PSA <4 ng/ml were randomized. If patients were progressive, LHRH analogues were added. Primary end point was time to PSA progression. A total of 366 patients were recruited; 258 reached a good response after 3 or 6 months and were randomized. A total of 131 patients randomized to IT and 127 to CT. Patients on IT had an average of 1.7 episodes on CPA, before LHRH analogues were started. The mean time without treatment in IT was 463 days versus 422 days on treatment. There were statistical significant differences between IT and CT in 3 of the 5 functional scales of EORTC QLQ C 30; however, the clinical relevance of this finding appears modest. Symptom and potency scales showed significant advantages for IT. There were no differences in time to PSA progression on CPA, time to PSA and/or clinical progression on LHRH analogues and time to cancer-specific and overall survival. IT by CPA is associated with less symptoms and modest advantages in QOL domains. There were no differences in time to PSA progression, clinical progression or survival.
A digital survey, combining photogrammetry and reflectance transformation imaging (RTI), offers s... more A digital survey, combining photogrammetry and reflectance transformation imaging (RTI), offers significant new insights into the British Museum's Easter Island statue called Hoa Hakananai'a. These include the likelihood that it was made with a tapering base to stand in the ground, as seen by the crew of HMS Topaze in 1868, and that a nearby stone described a century ago was a pukau, a stone ‘hat’. Petroglyphs consisting of two komari (stylised female genitalia) were subsequently added. Succeeding these were bas-relief carvings, here interpreted as a single composition that narrates the island's birdman myth as recorded in the nineteenth and early twentieth centuries. This reading is supported by photographs of Hoa Hakananai'a taken in Chile in 1868. A new model is presented for the relationship between the statue and the birdman cult. As it now stands, in a nineteenth-century plinth, Hoa Hakananai'a appears to lean slightly from its intended placing.
ABSTRACT This tutorial summarises our uses of reflectance transformation imaging in archaeologica... more ABSTRACT This tutorial summarises our uses of reflectance transformation imaging in archaeological contexts. It introduces the UK AHRC funded project reflectance Transformation Imaging for Anciant Documentary Artefacts and demonstrates imaging methodologies.
New methods of visualisation offer the potential for a more detailed record of archaeological obj... more New methods of visualisation offer the potential for a more detailed record of archaeological objects and the ability to create virtual 3D models that can be made widely available online. Here, two different techniques are applied to the impressive Easter Island statue on display in the Wellcome Gallery at the British Museum. Of particular importance are the details revealed of the petroglyphs that decorate its surface.
Introduction Digital archaeological analyses of space have proceeded traditionally from two disti... more Introduction Digital archaeological analyses of space have proceeded traditionally from two distinct perspectives. First, there has been a phenomenological appraisal of computer graphic modelled geometry, and second a formal analysis of the surviving spaces and extrapolations from them. The former approach encompasses work on the visualisation of raw geometric data captured through techniques such as laser scanning and photogrammetry. In addition it has considered to be significant the process and interfaces within which extrapolations from these data take place – namely the construction of increasingly sophisticated graphical simulations in software such as 3ds Max, Maya and Vue Infinite. Finally, it draws upon the ability of such software and interactive visualisation tools to stimulate new interpretations through interaction with the visualised geometry. This virtual phenomenology in turn has been seen to be significantly enhanced by an emphasis on physical realism (Chalmers 2002...
This full day tutorial will use lectures and demonstrations from leading researchers and museum p... more This full day tutorial will use lectures and demonstrations from leading researchers and museum practitioners to present the principles and practices for robust photography-based digital techniques in museum contexts. The tutorial will present many examples of existing and cutting-edge uses of photography-based imaging including Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR), camera calibration, and methods of imaged-based generation of textured 3D geometry. The tutorial will also explore a framework for Leading museums are now adopting the more mature members of this family of robust digital imaging practices. These practices are part of the emerging science known as Computational Photography (CP). The imaging family’s common feature is the purpose-driven selective extraction of information from sequences of standard digital photographs. The information is extracted from the photographic sequences by computer algorithms. The extracted information is then integ...
This paper will consider the possibilities for the use of Reflectance Transformation Imaging (RTI... more This paper will consider the possibilities for the use of Reflectance Transformation Imaging (RTI) and specifically Polynomial Texture Mapping (PTM) in the simulation of archaeologically derived materials. PTM was designed to enable complex surface shading of simulated textures, as an enhancement to bump mapping. However, whilst PTM and RTI files cannot be included in the rendering pipeline of standard tools such as Mental Ray we discuss in this paper the opportunities for repurposing RTI data in visualisation work. RTI is unique in allowing for the capture of a high resolution, highly versatile surface record whilst utilising commonly available, highly affordable equipment and software. Consequently RTI has become increasingly ubiquitous as a method for archaeological recording and a large and growing body of data exists. This paper will present some of the techniques which have been developed at the archaeological Computing Research Group at the University of Southampton which all...
Research institutions, funding bodies and researchers themselves are becoming increasingly aware ... more Research institutions, funding bodies and researchers themselves are becoming increasingly aware of the need to manage imaging and 3D data. At an institutional level data management policies are playing an increasingly significant role laying down plans for the provision of infrastructure, policy and guidance. Drawing upon the preliminary results of the University of Southampton’s JISC funded DataPool project, this paper will gauge the extent to which institutional policy development might be supplemented or even enhanced by an increased awareness of localised responses to the challenges of imaging and 3D data management. The paper will review approaches to data management that have been adopted by individuals and research groups and will propose that in many cases these developments might be pivotal in defining the form of institutional data management policy should take
Several thousand incised graffiti adorn the sandstone walls of the Great Enclosure at Musawwarat ... more Several thousand incised graffiti adorn the sandstone walls of the Great Enclosure at Musawwarat es Sufra (Sudan), a unique sacral building complex dating to the Meroitic period (c. 270BC-AD350) of the Kingdom of Kush. The often finely incised informal inscriptions and images – rare evidence of non-official art and ritual practice – are threatened by accelerated weathering and the negative side effects of increased tourism. Several past attempts at documenting the hitherto unpublished graffiti corpus have been hampered by limitations inherent in traditional photographic and other graphic recording techniques. In 2009 white light scanning was tested on some graffiti with good results, but its high cost and the loss of important colour information limited its application. In 2011 low-cost Reflectance Transformation Imaging (RTI), which captures surface details in different lighting conditions, was tested on a large sample of graffiti. RTI is based on traditional raking light photograp...
Polynomial Texture Mapping (PTM; Malzbender et al 2001) uses multiple images to capture the refle... more Polynomial Texture Mapping (PTM; Malzbender et al 2001) uses multiple images to capture the reflectance properties of a given surface. Multiple captures may be combined in order to produce interactive, relit records of the material recorded. In addition recent research enables the capture and rendition of interactive PTMs for detailed examination of surface details. Cultural heritage examples of the technology include work on Cuneiform tablets, numismatic archives and lithic artefacts. This paper will describe the PTM data capture and processing technologies developed by the University of Southampton, with support from Hewlett Packard Labs Palo Alto. It will also identify the perceived archaeological potential of additional recording to supplement the standard PTM datasets, including the recording of the surface BRDF (bi-directional reflectance distribution function) and accurate extraction of surface normals. Such data offer considerable, under-exploited value in production of comp...
Reflectance Transformation Imaging (RTI) is a technology that uses conventional digital photograp... more Reflectance Transformation Imaging (RTI) is a technology that uses conventional digital photographs to derive detailed surface shape information (Figure 1). It is a digital, interactive version of the raking light photography commonly used in finds photography and (with the sun) on site to represent subtle changes in surface morphology. The University of Southampton is currently leading a project in collaboration with Oxford University funded by the AHRC further to develop and promote the RTI technology. We recently provided a demonstration of the available tools at the IfA conference on April 11th 2011.
The analysis of surface bone changes is an essential aspect of the paleopathological examination ... more The analysis of surface bone changes is an essential aspect of the paleopathological examination of skeletal remains from archaeological and forensic contexts, and proper digital imaging is an indispensable aspect of the documentation of bone modifications. This paper evaluates the applicability of Reflectance Transformation Imaging (RTI) to the study of pathological bone surface changes in human remains. Forty-five samples of human bones and teeth from medieval and early modern Estonian cemeteries were photographed and subjected to RTI imaging to document the pathological conditions that typically result in subtle surface modifications. Subperiosteal Bone Production (SBP), abnormal porosity, cribra orbitalia, endocranial lesions and lytic lesions in bone, as well as enamel hypoplasia and dental calculus in teeth were successfully represented with this technique. The results indicate that RTI allows visualization of shallow and discrete bone changes that are otherwise unnoticed. In some cases, this technique provides a better understanding of the nature and development of particular pathological processes than possible with conventional imaging. Although it cannot entirely replace microscopic and radiological techniques, RTI can be successfully performed in a reasonably short time by non-specialist operators with limited funding and resources, thus enabling identification of specimens that should be subject to more expensive or time-consuming analyses. Hence, RTI constitutes a valuable tool for the representation of subtle surface details in pathological bone, and can successfully support standard photography in paleopathological studies, museum display and scientific communication.
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Papers by Hembo Pagi