Stereo Visualisation of Historical Aerial Photos - a Valuable Digital Heritage Research Tool

We demonstrate with several examples how historical aerial photos can benefit from being viewed in stereo and how this can be useful as tool in digital heritage research. The main reason why stereo images are important is that they give a much better understanding of what is actually in the scene than single photos can. The important factor is the depth cue that helps understanding the content and adds the ability to distinguish between objects such as houses and trees and the ground as well as estimating heights of objects. There are however still challenges but also possibilities that will be discussed

Determining estuarine seagrass density measures from low altitude multispectral imagery flown by remotely piloted aircraft

Seagrass is the subject of significant conservation research. Seagrass is ecologically important and of significant value to human interests. Many seagrass species are thought to be in decline. Degradation of seagrass populations are linked to anthropogenic environmental issues. Effective management requires robust monitoring that is affordable at large scale. Remote sensing methods using satellite and aircraft imagery enable mapping of seagrass populations at landscape scale. Aerial monitoring of a seagrass population can require imagery of high spatial and/or spectral resolution for successful feature extraction across all levels of seagrass density. Remotely piloted aircraft (RPA) can operate close to the ground under precise flight control enabling repeated surveys in high detail with accurate revisit-positioning. This study evaluates a method for assessing intertidal estuarine seagrass (Zostera muelleri) presence/absence and coverage density using multispectral imagery collected by a remotely piloted aircraft (RPA) flying at 30 m above the estuary surface (2.7 cm ground sampling distance). The research was conducted at Wharekawa Harbour on the eastern coast of the Coromandel Peninsula, North Island, New Zealand. Differential drainage of residual ebb waters from the surface of an estuary at low tide creates a mosaic of drying sediment, draining surface and static shallow pooling that has potential to interfere with spectral observations. The field surveys demonstrated that despite minor shifts in the spectral coordinates of seagrass and other surface material, there was no apparent difference in image classification outcome from the time of bulk tidal water clearance to the time of returning tidal flood. For the survey specification tested, classification accuracy increased with decreasing segmentation scale. Pixel-based image analysis (PBIA) achieved higher classification accuracy than object-based image analysis (OBIA) assessed at a range of segmentation scales. Contaminating objects such as shells and detritus can become aggregated within polygon objects when OBIA is applied but remain as isolated objects under PBIA at this image resolution. There was clear separability of spectra for seagrass and sediment, but shell and detritus confounded the classification of seagrass density in some situations. High density seagrass was distinct from sediment, but classification error arose for sparse seagrass. Three classifiers (linear discriminant analysis, support vector machine and random forest) and three feature selection options (no selection, collinearity reduction and recursive feature elimination) were assessed for effect on classification performance. The random forest classifier yielded the highest classification accuracy, with no accuracy benefit gained from collinearity reduction or recursive feature elimination. Spectral vegetation indices and texture layers substantially improved classification accuracy. Object geometry made a negligible contribution to classification accuracy using mean-shift segmentation at this image-scale. The method achieved classification of seagrass density with up to 84% accuracy on a three-tier end-member class scale (low, medium, and high density) when using training data formed using visual interpretation of ground reference photography, and up to 93% accuracy using precisely measured seagrass leaf-area. Visual interpretation agreed with precisely measured seagrass leaf area 88% of the time with some misattribution at mid-density. Visual interpretation was substantially faster to apply than measuring the leaf area. A decile class scale for seagrass density correlated with actual leaf area measures more than the three-tier scale, however, was less accurate for absolute class attribution. The research demonstrates that seagrass feature extraction from RPA-flown imagery is a feasible and repeatable option for seagrass population monitoring and environmental reporting. Further calibration is required for whole- and multi-estuary application

The development of methods for the reproduction in continuous tone of digitally printed colour artworks

Advances in printing technologies in the late 19th century led to the development of half-toning techniques enabling the economical reproduction of photographic images in print. Whilst undoubtedly successful in low cost high volume image reproduction, half-toning representations are less faithful in detail when compared to continuous tone photomechanical methods in use at that time. This thesis asks the question: can the creative application of 21st century digital fabrication technologies enable the qualities of continuous tone imaging to be regained? In the 21st-century, printmaking may be seen as the interchange of ideas, experimental practice and interdisciplinary thinking. Printmaking has always been a means of combining modern technology and methods with existing traditional and commercial imaging processes. Technological advancement in print however does not always provide a finer quality of print. Qualities often attributed to pre-digital continuous tone printing can be lost in the transition to a digital half tone print workflow. This research project examines a near obsolete 19th century print process, the continuous tone Woodburytype, developed to address the issue of permanence in photography. Through a methodological approach analyses of the Woodburytype an empirical reconstruction of the process provides a comprehensive critique of its method. The Woodburytype’s surface qualities are not found in other photomechanical printing methods capable of rendering finely detailed photographic images. Its method of image translation results in the printed tonal range being directly proportional to the deposition thickness of the printing ink, however it never successfully developed into a colour process. By examining and evaluating digital imaging technology this study identifies, current computer aided design and manufacturing techniques and extends upon known models of Woodburytype printing through the development of this deposition height quality enabling a new digital polychromatic colour printing process

Evaluation of the region-specific risks of accidental radioactive releases from the European Spallation Source

The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range ofradionuclides that could be released into the environment. Some radionuclides are of particular concern such as the rare earth gadolinium-148. In this article, the local environment was investigated in terms of food production and rare earth element concentration in soil. The collected data will later be used to model thetransfer of radioactive contaminations from the ESS

Digital Light

Light symbolises the highest good, it enables all visual art, and today it lies at the heart of billion-dollar industries. The control of light forms the foundation of contemporary vision. Digital Light brings together artists, curators, technologists and media archaeologists to study the historical evolution of digital light-based technologies. Digital Light provides a critical account of the capacities and limitations of contemporary digital light-based technologies and techniques by tracing their genealogies and comparing them with their predecessor media. As digital light remediates multiple historical forms (photography, print, film, video, projection, paint), the collection draws from all of these histories, connecting them to the digital present and placing them in dialogue with one another. Light is at once universal and deeply historical. The invention of mechanical media (including photography and cinematography) allied with changing print technologies (half-tone, lithography) helped structure the emerging electronic media of television and video, which in turn shaped the bitmap processing and raster display of digital visual media. Digital light is, as Stephen Jones points out in his contribution, an oxymoron: light is photons, particulate and discrete, and therefore always digital. But photons are also waveforms, subject to manipulation in myriad ways. From Fourier transforms to chip design, colour management to the translation of vector graphics into arithmetic displays, light is constantly disciplined to human purposes. In the form of fibre optics, light is now the infrastructure of all our media; in urban plazas and handheld devices, screens have become ubiquitous, and also standardised. This collection addresses how this occurred, what it means, and how artists, curators and engineers confront and challenge the constraints of increasingly normalised digital visual media. While various art pieces and other content are considered throughout the collection, the focus is specifically on what such pieces suggest about the intersection of technique and technology. Including accounts by prominent artists and professionals, the collection emphasises the centrality of use and experimentation in the shaping of technological platforms. Indeed, a recurring theme is how techniques of previous media become technologies, inscribed in both digital software and hardware. Contributions include considerations of image-oriented software and file formats; screen technologies; projection and urban screen surfaces; histories of computer graphics, 2D and 3D image editing software, photography and cinematic art; and transformations of light-based art resulting from the distributed architectures of the internet and the logic of the database. Digital Light brings together high profile figures in diverse but increasingly convergent fields, from academy award-winner and co-founder of Pixar, Alvy Ray Smith to feminist philosopher Cathryn Vasseleu

Digital light

Light symbolises the highest good, it enables all visual art, and today it lies at the heart of billion-dollar industries. The control of light forms the foundation of contemporary vision. Digital Light brings together artists, curators, technologists and media archaeologists to study the historical evolution of digital light-based technologies. Digital Light provides a critical account of the capacities and limitations of contemporary digital light-based technologies and techniques by tracing their genealogies and comparing them with their predecessor media. As digital light remediates multiple historical forms (photography, print, film, video, projection, paint), the collection draws from all of these histories, connecting them to the digital present and placing them in dialogue with one another.Light is at once universal and deeply historical. The invention of mechanical media (including photography and cinematography) allied with changing print technologies (half-tone, lithography) helped structure the emerging electronic media of television and video, which in turn shaped the bitmap processing and raster display of digital visual media. Digital light is, as Stephen Jones points out in his contribution, an oxymoron: light is photons, particulate and discrete, and therefore always digital. But photons are also waveforms, subject to manipulation in myriad ways. From Fourier transforms to chip design, colour management to the translation of vector graphics into arithmetic displays, light is constantly disciplined to human purposes. In the form of fibre optics, light is now the infrastructure of all our media; in urban plazas and handheld devices, screens have become ubiquitous, and also standardised. This collection addresses how this occurred, what it means, and how artists, curators and engineers confront and challenge the constraints of increasingly normalised digital visual media.While various art pieces and other content are considered throughout the collection, the focus is specifically on what such pieces suggest about the intersection of technique and technology. Including accounts by prominent artists and professionals, the collection emphasises the centrality of use and experimentation in the shaping of technological platforms. Indeed, a recurring theme is how techniques of previous media become technologies, inscribed in both digital software and hardware. Contributions include considerations of image-oriented software and file formats; screen technologies; projection and urban screen surfaces; histories of computer graphics, 2D and 3D image editing software, photography and cinematic art; and transformations of light-based art resulting from the distributed architectures of the internet and the logic of the database.Digital Light brings together high profile figures in diverse but increasingly convergent fields, from academy award-winner and co-founder of Pixar, Alvy Ray Smith to feminist philosopher Cathryn Vasseleu