Assessing the Viability of Complex Electrical Impedance Tomography (EIT) with a Spatially Distributed Sensor Array for Imaging of River Bed Morphology: a Proof of Concept (Study)

This report was produced as part of a NERC funded ‘Connect A’ project to establish a new collaborative partnership between the University of Worcester (UW) and Q-par Angus Ltd. The project aim was to assess the potential of using complex Electrical Impedance Tomography (EIT) to image river bed morphology. An assessment of the viability of sensors inserted vertically into the channel margins to provide real-time or near real-time monitoring of bed morphology is reported. Funding has enabled UW to carry out a literature review of the use of EIT and existing methods used for river bed surveys, and outline the requirements of potential end-users. Q-par Angus has led technical developments and assessed the viability of EIT for this purpose. EIT is one of a suite of tomographic imaging techniques and has already been used as an imaging tool for medical analysis, industrial processing and geophysical site survey work. The method uses electrodes placed on the margins or boundary of the entity being imaged, and a current is applied to some and measured on the remaining ones. Tomographic reconstruction uses algorithms to estimate the distribution of conductivity within the object and produce an image of this distribution from impedance measurements. The advantages of the use of EIT lie with the inherent simplicity, low cost and portability of the hardware, the high speed of data acquisition for real-time or near real-time monitoring, robust sensors, and the object being monitored is done so in a non-invasive manner. The need for sophisticated image reconstruction algorithms, and providing images with adequate spatial resolution are key challenges. A literature review of the use of EIT suggests that to date, despite its many other applications, to the best of our knowledge only one study has utilised EIT for river survey work (Sambuelli et al 2002). The Sambuelli (2002) study supported the notion that EIT may provide an innovative way of describing river bed morphology in a cost effective way. However this study used an invasive sensor array, and therefore the potential for using EIT in a non-invasive way in a river environment is still to be tested. A review of existing methods to monitor river bed morphology indicates that a plethora of techniques have been applied by a range of disciplines including fluvial geomorphology, ecology and engineering. However, none provide non-invasive, low costs assessments in real-time or near real-time. Therefore, EIT has the potential to meet the requirements of end users that no existing technique can accomplish. Work led by Q-par Angus Ltd. has assessed the technical requirements of the proposed approach, including probe design and deployment, sensor array parameters, data acquisition, image reconstruction and test procedure. Consequently, the success of this collaboration, literature review, identification of the proposed approach and potential applications of this technique have encouraged the authors to seek further funding to test, develop and market this approach through the development of a new environmental sensor

DEVELOPMENT OF AN EFFICIENT APPROACH OF ARCHAEOLOGICAL HERITAGE IN THE INTERTIDAL ZONE OF THE BELGIAN NORTH SEA

[EN] The knowledge of the submerged cultural heritage in the North Sea is rather limited. The Belgian North Sea is being used for a lot of different purposes, such as fishing, aggregate extraction, wind farms, dredging, etc. Due to these increasing economic activities, the underwater archive is in danger. In the context of the UNESCO Convention on the Protection of the Underwater Cultural Heritage of 2001, gathering more information about the submerged cultural heritage in the intertidal zones of the North Sea is one of the main objectives of the Belgian scientific project ‘SeArch’. It will give a clearer picture of the broader cultural and archaeological heritage in the region and it can be used as a basis for a sustainable management by government agencies. The Department of Geography (Ghent University, Belgium) contributes to the SeArch project in two ways. First, an innovative survey methodology has been developed which allows an accurate and cost-efficient evaluation of the archaeological potential in the intertidal zones of the Belgian beaches. Secondly, the Department of Geography is developing an interactive webGIS platform, which makes it possible to share, integrate and visualize the gathered archaeological and environmental data and information in a user-friendly way. Hereby, the total potential of this project is fully exploited in a time-efficient manner. To create an interactive webGIS platform, a good structured spatial database is needed. It enables manipulation of a wide variety of georeferenced information in both raster and vector formats. This paper provides more information about the configuration and application of the spatial database. Moreover, it focusses on the development of a fully functional Spatial Data Infrastructure (SDI) using the most reliable, powerful and state-of-the-art technological components. Besides, a new way of collecting geomatic data in a fast and accurate manner will be discussed. Some processing results will show the possibilities for detecting and visualizing underground structures and archaeological objects.Decock, M.; Stal, C.; Van Ackere, S.; Vandenbulcke, A.; De Maeyer, P.; De Wulf, A. (2016). DEVELOPMENT OF AN EFFICIENT APPROACH OF ARCHAEOLOGICAL HERITAGE IN THE INTERTIDAL ZONE OF THE BELGIAN NORTH SEA. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 138-145. https://doi.org/10.4995/arqueologica8.2015.3554OCS13814

Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean

This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features

Preparing for the future: A reappraisal of archaeo-geophysical surveying on Irish National Road Schemes 2001-2010

yesThis document reviews Legacy Data generated from 10 years’ worth of road scheme activity in Ireland to determine how archaeological geophysical surveys could be carried out on national roads in the future. The geophysical surveys were carried out by several different contractors across a range of challenging field conditions, geologies, weather and seasons. The research is based upon the results of linear schemes but also has validity for wider approaches. The findings of this research are based upon the compilation of all terrestrial archaeological geophysical surveys carried out on behalf of the National Roads Authority (NRA), a review of the success or otherwise of those surveys in comparison with ground-observed excavations and in combination with experimental surveys that tested previously held assumptions or knowledge to determine best practice methods for the future. The use and success of geophysical surveys in Ireland differ quite significantly from those in the UK, from where many of the methods of assessment were derived or adapted. Many of these differences can be attributed to geology. Ireland has a very high percentage of Carboniferous limestone geology, overlain mostly by tills and frequent occurrences of peat. These soils can reduce, to some extent, the effectiveness of magnetometer surveys; the most frequently used geophysical technique in Ireland. However, magnetometer data can be maximised in these cases by increasing the spatial resolution to produce effective results. An increase in spatial resolution is also effective generally, for enhancing the chances of identifying archaeological features by discriminating between archaeological and geological anomalies as well as increasing anomaly definition and visualisation of small and subtle archaeological features. Seasonal tests have determined that Irish soils are generally suitable for year round earth resistance assessments although some counties in the southeast of the country may experience very dry soils at the surface during some periods of the year. A variety of sampling strategies were used in the past, however it is now apparent that detailed assessments across the full length and width of a proposed road corridor are the most appropriate form of geophysical investigation. Magnetometer surveys are generally suitable for most Irish soils and geologies, although exceptions apply in areas of near-surface igneous deposits, deep peat and alluvial soils; however magnetometer surveys are not capable of identifying all types of archaeological features and other methods will be required for a full evaluation. Analysis of the Legacy Data has determined that in general the NRA archaeological geophysical surveys were historically used in a very positive way on road schemes. The range of features assessed or identified account for most types of archaeological sites in Ireland. These have provided a significant archive of case studies that will be of benefit to future archaeological geophysical research and will help to protect the globally dwindling archaeological resource that is threatened by development-led or commercially driven projects

Helium balloons for 3D modelling : off to a flying start?

Currently, the use of unmanned aerial vehicles (UAV) as a platform for aerial photography is becoming more and more common practice for 3D photo modelling applications. However, the use of these platforms has several drawbacks. Firstly, to recharge the UAV’s batteries a nearby electricity source is needed. This might cause problems when performing research in remote areas. Secondly, a skilled operator is required to control the UAV. Thirdly, there might be legal restrictions to the use of such an aerial platform in several countries. Finally, purchasing a UAV can form a big cost when performing a small project. To address these issues, the use of helium balloons as an alternative and low cost platform for aerial photography is proposed. To assess its efficiency, effectiveness and accuracy, several case studies are elaborated. In the first case study the accuracy of a 3D model created by laser scanning is compared with a 3D model created by helium balloon imagery (Ghent, Belgium). The second case study comprises a test of the performance of the system used at the lake of Vassivière (France). Finally, the helium balloons are deployed on the archaeological site of Edzna (Mexico). Here, a comparison is made between the accuracy of 3D models generated by UAV and helium balloon imagery. In conclusion, the advantages and drawbacks of the use of helium balloons as platform for aerial photography are listed. This allows potential users to make an informed choice between this and other platforms

Rock Art Pilot Project Main Report

A report on the results of a pilot project to investigate the current state of research, conservation, management and presentation of prehistoric rock art in England commissioned by English Heritage from Archaeology Group, School of Conservation Sciences, Bournemouth Unviersity and the Institute of Archaeology, University College Londo

Remote spectral imaging with simultaneous extraction of 3D topography for historical wall paintings

PRISMS (Portable Remote Imaging System for Multispectral Scanning) is designed for in situ, simultaneous high resolution spectral and 3D topographic imaging of wall paintings and other large surfaces. In particular, it can image at transverse resolutions of tens of microns remotely from distances of tens of metres, making high resolution imaging possible from a fixed position on the ground for areas at heights that is difficult to access. The spectral imaging system is fully automated giving 3D topographic mapping at millimetre accuracy as a by-product of the image focusing process. PRISMS is the first imaging device capable of both 3D mapping and spectral imaging simultaneously without additional distance measuring devices. Examples from applications of PRISMS to wall paintings at a UNESCO site in the Gobi desert are presented to demonstrate the potential of the instrument for large scale 3D spectral imaging, revealing faded writing and material identification

Assessment of the CORONA series of satellite imagery for landscape archaeology: a case study from the Orontes valley, Syria

In 1995, a large database of satellite imagery with worldwide coverage taken from 1960 until 1972 was declassified. The main advantages of this imagery known as CORONA that made it attractive for archaeology were its moderate cost and its historical value. The main disadvantages were its unknown quality, format, geometry and the limited base of known applications. This thesis has sought to explore the properties and potential of CORONA imagery and thus enhance its value for applications in landscape archaeology. In order to ground these investigations in a real dataset, the properties and characteristics of CORONA imagery were explored through the case study of a landscape archaeology project working in the Orontes Valley, Syria. Present-day high-resolution IKONOS imagery was integrated within the study and assessed alongside CORONA imagery. The combination of these two image datasets was shown to provide a powerful set of tools for investigating past archaeological landscape in the Middle East. The imagery was assessed qualitatively through photointerpretation for its ability to detect archaeological remains, and quantitatively through the extraction of height information after the creation of stereomodels. The imagery was also assessed spectrally through fieldwork and spectroradiometric analysis, and for its Multiple View Angle (MVA) capability through visual and statistical analysis. Landscape archaeology requires a variety of data to be gathered from a large area, in an effective and inexpensive way. This study demonstrates an effective methodology for the deployment of CORONA and IKONOS imagery and raises a number of technical points of which the archaeological researcher community need to be aware of. Simultaneously, it identified certain limitations of the data and suggested solutions for the more effective exploitation of the strengths of CORONA imagery