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Marc Walton - IEEE Xplore Author Profile

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X-ray fluorescence (XRF) analysis of art objects has rapidly gained popularity since the late 2000s due to its increased accessibility to scientists. This introduced an imaging component whereby the XRF image volume provides clues as to which chemical elements are present and where they are located spatially in the object. However, as is the nature of collecting measurements, there are limitations...Show More
Computational photography has become a valuable field of interest for dermatologists. Current telemedical approaches mainly use two-dimensional (2D) color imagery, which cannot always capture sufficient information for the physician. In clinical practice dedicated imaging systems can acquire valuable three-dimensional (3D) data to improve the patients outcome [1], [2]. The major drawback of clinic...Show More
The utilization of computational photography becomes increasingly essential in the medical field. Today, imaging techniques for dermatology range from two-dimensional (2D) color imagery with a mobile device to professional clinical imaging systems measuring additional detailed three-dimensional (3D) data. The latter are commonly expensive and not accessible to a broad audience. In this work, we pr...Show More
In this manuscript, we address the problem of studying layer structure in X-ray Fluorescence (XRF) elemental maps of paintings through the incorporation of reflectance imaging spectral data in the visible or near IR range. We propose a conceptually flexible approach, which involves an initial clustering step for the visible hyperspectral reflectance data (RIS) and the formation of a synthetic surf...Show More
In this paper, we present recent results on our effort to develop low-budget, high precision 3D scanning solutions for art museum conservators. There is a real need for this in cultural heritage applications where the potential to detect and monitor degradations is of critical importance, but financial resources for high-quality 3D scanning devices is limited to a select few larger institutions. T...Show More
This paper presents an adaptive image sampling algorithm based on Deep Learning (DL). It consists of an adaptive sampling mask generation network which is jointly trained with an image inpainting network. The sampling rate is controlled by the mask generation network, and a binarization strategy is investigated to make the sampling mask binary. In addition to the image sampling and reconstruction ...Show More
Surface shape metrology encompasses broad topics within cultural heritage science. However, most existing surface shape measurement systems are bulky and restricted to lab environments. As most are not practical for large, delicate or fixed works of art, such as stained-glass windows or oil-painted murals, we develop methods to measure matte and specular surfaces using hand-held mobile devices. In...Show More
In this paper, the problem of automatic nonlinear unmixing of hyperspectral reflectance data using works of art as test cases is described. We use a deep neural network to decompose a given spectrum quantitatively to the abundance values of pure pigments. We show that adding another step to identify the constituent pigments of a given spectrum leads to more accurate unmixing results. Towards this,...Show More
Surface shape scanning techniques, such as laser scanning and photometric stereo, are widespread analytical tools used in the field of cultural heritage. Compared to regular 2D RGB photos, 3D surface scans provide higher fidelity of an object's surface shape which assist conservators, art historians, and archaeologists in understanding how these artworks and artifacts are made and to digitally doc...Show More
X-ray fluorescence (XRF) scanning of works of art is becoming an increasing popular nondestructive analytical method. The high quality XRF spectra is necessary to obtain significant information on both major and minor elements used for characterization and provenance analysis. However, there is a tradeoff between the spatial resolution of an XRF scan and the signal-to-noise ratio (SNR) of each pix...Show More
In this paper, we study the problem of automatic identification of pigments applied to paintings using hyperspectral reflectance data. Here, we cast the problem of pigment identification in a novel way by decomposing the spectrum into pure pigments. The pure pigment exemplars, chosen and prepared in our laboratory based on historic sources and archaeological examples, closely resemble the material...Show More
Because art is inherently visual, the use of imaging has long been an important way to understand its structure, form, and history. Recently, new ways of engaging with objects from our shared cultural heritage are possible with advances in computation and imaging that allow scientists to analyze art noninvasively, historians to pose new social questions about the art, and the public to explore and...Show More
X-Ray fluorescence (XRF) scanning of works of art is becoming an increasingly popular non-destructive analytical method. The high quality XRF spectra is necessary to obtain significant information on both major and minor elements used for characterization and provenance analysis. However, there is a trade-off between the spatial resolution of an XRF scan and the Signal-to-Noise Ratio (SNR) of each...Show More
This talk will discuss (from the viewpoint of a physicist with background in optical engineering and information) how much imaging and how much computing is (or should be) in computational imaging, aiming for high information efficiency. For an opticist the order of the keywords “computational imaging” is inverted: imaging is the first operation in the sequence, as optics does the encoding for red...Show More
Starting in the 1890s the artist Paul Gauguin (1848-1903) created a series of prints and transfer drawings using techniques that are not entirely understood. To better understand the artist's production methods, photometric stereo was used to assess the surface shape of a number of these graphic works that are now in the collection of the Art Institute of Chicago. Photometric stereo uses multiple ...Show More
We propose quantifying color in crowd-sourced images from mobile phones to monitor built heritage over time. Time-lapse color movies in CIE color space can provide information on a large range of deterioration mechanisms, including soiling, biofilm growth, weathering and vandalism. Citizen science can create large-scale geographical coverage of sites difficult to obtain any other way. We show that...Show More
In this paper, we propose a near-light illumination model for image relighting and 3D shape recovery. Classic methods such as used by the popular RTI software from Cultural Heritage Imaging assume that lighting is infinitely far away from the scene. However, this constraint is impossible to achieve in practice: light sources cannot be too far away from the scene due to space and power constraints....Show More