This PDF file contains the front matter associated with SPIE Proceedings Volume 8084, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

In 1964 a human skeleton was discovered in the sediments of the Columbia River near Kennewick, Washington (the extreme northwest portion of the United States). Subsequently, these bones were analyzed in several scientific laboratories and dated at more than 6000 years BP. Now known as "Kennewick Man", the remains are associated with the "Clovis Period" and, indeed, a Clovis spear point was discovered imbedded in the bone of the pelvis. Equally significant were DNA results indicating the individual was of Caucasian racial origin. Consequently, this sensational archaeological discovery stimulated widespread debates concerning the populating of the Western Hemisphere: the migration routes, the eras of the waves of migration, and the peoples involved. In spite of the enormous historical and cultural significance of the Kennewick find, contemporary Native American Indian Tribes (Nez Perce, Umatilla, Yakima, Wannapum, Colville) prevailed in the courts and were awarded the bones for a "dignified" and "sacred" reburial on the Columbia River bank at the discovery location. Whereas this reburial may have been culturally sensitive, it was both dangerous and imprudent. The internment site is only a short distance downriver from one of the most contaminated nuclear repositories in the world. The Hanford Nuclear Reservation has twelve shutdown atomic reactors that were constructed almost seventy years ago and built for the production of plutonium. The facility also encompasses five chemical-processing complexes for the extraction and refining of plutonium. During the past few decades many of the reactors, as well as their single-wall waste storage tanks and ponds, have deteriorated and have been leaking radioactive and toxic-chemical waste into the local aquifer. This contaminated ground water has been seeping ever closer to the banks of the Columbia River and the resting place of Kennewick Man and other associated (yet to be found) artifacts. Without remediative steps the toxic flow will continue past Kennewick to threaten cities such as Portland with a Chernobyl-like tragedy. Consequently, a remediation program was initiated to drain the leaking tanks and ponds so that the toxic wastes could be buried elsewhere and/or transferred to more secure double-shell reservoirs. Unfortunately, hazardous substances adhere to pores and corrosion on the vessel walls after draining. This poses problems when disposing of refuse materials and hardware from the site. It has been experimentally determined that this hazardous surface contamination may be ejected by means of radiation ablation. It was concluded that this is most effectively accomplished with underwater flashlamp irradiation. In this manner the dislodged surface contamination is freed to float in the water and is then captured and concentrated by the filters of the fluid circulation systems. The final phase of the project was assistance in designing a Stonehenge-like monument to celebrate the cleanup of the Hanford Reservation and the removal of the radioactive threat to the final resting place of Kennewick Man ("The Ancient One").

In this paper a new compact and portable instrument for combined reflectance, time-resolved and steady-state fluorescence is presented. All the optical parts of the apparatus, carefully described in the text, were chosen after an extensive market survey in order to obtain the best performances coupled with the smallest dimensions. This instrument through the use of a dedicated multiple fiber optic probe, allows the complete photophysical behaviors of investigated materials to be collected from the same point of the analyzed surface. In this way, the resultant instrumental setup is a portable device, usable in situ for non destructive and non invasive diagnostic purposes in the field of cultural heritage. Preliminary results concerning organic dyes characterization, which is the main application of luminescence-based diagnostic techniques in artworks, are presented and compared with those previously obtained using separate devices. Concerning reflectance data, improvements in the deep detectable UV spectral range have been achieved switching from the integrating sphere of the old instrument to bifurcated optical fibers used as probe in the new one. Special attention was devoted to test the instrument capability in order to obtain the true emission spectrum, corrected for the selfabsorption effect, for which good results were found. This particular experimental procedure is strongly recommended, by a diagnostic point of view, to avoid distortions in the instrumental responses, namely the spectral shape and emission maximum wavelength of a fluorophore as function of the color saturation.

A variety of optical investigation methods applied to paintings are, by now, an integral part of the repair process, both to plan the restoration intervention and to monitor its various phases. Among them infrared reflectography in wide-band modality is traditionally employed in non-invasive diagnostics of ancient paintings to reveal features underlying the pictorial layer thanks to transparency characteristics to NIR radiation of most of the materials composing the paints. This technique was improved with the introduction of the multi-spectral modality that consists in acquiring the radiation back scattered from the painting into narrow spectral bands. The technology, widely used in remote sensing applications such as satellite or radar imaging, has only recently gained importance in the field of artwork conservation thanks to the varied reflectance and transmittance of pigments over this spectral region. In this work we present a scanning device for multi-NIR spectral imaging of paintings, based on contact-less and singlepoint measurement of the reflectance of painted surfaces. The back-scattered radiation is focused on square-shaped fiber bundle that carries the light to an array of 16 photodiodes equipped with pass-band filters so to cover the NIR spectral range from 900 to 2500 nm. In particular, we describe the last instrument upgrade that consists in the addition of an autofocus system that keeps the optical head perfectly focused during the scanning. The output of the autofocus system can be used as a raw map of the painting shape.

Imaging methods offer several advantages in the field of conservation allowing to perform non-invasive inspection of works of art. In particular, non-invasive techniques based on imaging in different infrared (IR) regions are widely used for the investigation of paintings. Using radiation beyond the visible range, different characteristics of the inspected artwork may be revealed according to the bandwidth acquired. In this paper we present the recent results of a joint project among the two research institutes DIMEG and CNR-INO, and the restoration facility Opificio delle Pietre Dure, concerning the wide-band integration of IR imaging techniques, in the spectral ranges NIR 0.8-2.5 μm, MIR 3-5 μm, and FIR 8-12 μm, for in situ analysis of artworks. A joint, multi-mode use of reflection and thermal bands is proposed for the diagnostics of mural paintings, and it is demonstrated to be an effective tool in inspecting the layered structure. High resolution IR reflectography and, to a greater extent, IR imaging in the 3-5 μm band, are effectively used to characterize the superficial layer of the fresco and to analyze the stratigraphy of different pictorial layers. IR thermography in the 8-12 μm band is used to characterize the support deep structure. The integration of all the data provides a multi- layered and multi-spectral representation of the fresco that yields a comprehensive analysis.

Imaging spectroscopy (IS) extends the measurement of one-dimensional UV-VIS-NIR spectroscopy to two-dimensional domain providing material characterization and localization. The technique is gaining importance for the study of cultural heritage but its application is mainly focused on the analysis of pigments in paintings. An IS device has been developed and then applied to the study of chromophores in glassy objects. It consists of a visible imaging spectrograph, mounted on a rotation stage, which captures monochromatic images of the sample within a wavelength range from 420 nm to 850 nm. The system has been used for the characterization and mapping of chromophores of hundreds of coloured glass tesserae of the stained glass windows from the Scrovegni Chapel (Padua, Italy). Two measurement methodologies have been performed: transmission and double-transmission modes. In the first case, lamps used to illuminate the sample and the spectrograph are placed on the opposite side of the window, to acquire directly the signal transmitted from the glass. In the latter case, the lamps and the spectrograph are placed on the same side of the window, that is placed on a white scattering screen. The acquired signal comes from the light of the lamps transmitted through the glass, then diffused back by the opaque white screen and finally transmitted again through the glass. Results are discussed comparing both modalities in terms of signal-to-noise ratio and spectral contrast. Visible spectra acquired allow the clear identification of several chromophores, e.g. Co(II), Cr(III) or Mn(III). The IS device acquires numerous spectra in relatively short time in a non-invasive way. According to the authors knowledge, this is the first time in which visible imaging spectroscopy technique has been applied for the study of stained glass windows. As the results show, it could represent a powerful and innovative tool to map chromophores of this kind of artefact, particularly when integrated with other non-invasive techniques as X-ray fluorescence.

Hyper-Spectral Imaging (HSI) has emerged in the last decade as one of the most promising technologies for diagnostics and documentation of polychrome surfaces. Despite the fact that presently HSI is a well-established technique for non-invasive investigations on paintings, a number of technological issues remain open and are still topics for on-going studies. In particular, it is known that high spatial resolution is a crucial parameter for obtaining high quality images, whereas the possibility to identify pictorial materials strictly depends on the spectral resolution and on the extent of the spectral region investigated. At the same time, by increasing the sampling rates in both the spatial and spectral dimensions, the size of the data-set will be enlarged and the acquisition times will be lengthened. As a consequence, a good compromise between the acquisition of highquality data and their application should always be reached, taking into account the specific purposes of the HSI application. The above questions are discussed in the present work, which illustrates two applications of the latest version of a hyperspectral scanner designed at IFAC-CNR for the digitization of artworks. The prototype has recently been upgraded, with new visualization software as well as mechanical and optical improvements. This high performance system operates in the 400-1000nm spectral range, with a spectral resolution of about 2-3 nm and a spatial sampling of 0.1 mm over areas of about 1 m². Three case-studies are presented, which highlight the importance of both high spatial and high spectral sampling rate in hyperspectral imaging. Two of the examples reported focus on the full exploitation of the spatial resolution: the first one is a study performed on a small painting, dated from the eighteenth century and belonging to the Uffizi Gallery in Florence; the second case-study refers to the valuable "Carrand diptych" (14^th century) from the Bargello Museum in Florence. The last application, instead, shows the crucial importance of a high spectral resolution to identify selected pigments in the oil-painting "Ritratto di Maffeo Barberini", dated around 1596-1600, which has recently been attributed to Caravaggio.

Terahertz pulse imaging (TPI) is a novel noncontact, nondestructive technique for the examination of cultural heritage artifacts. It has the advantage of broadband spectral range, time-of-flight depth resolution, and penetration through optically opaque materials. Fiber-coupled, portable, time-domain terahertz systems have enabled this technique to move out of the laboratory and into the field. Much like the rings of a tree, stratified architectural materials give the chronology of their environmental and aesthetic history. This work concentrates on laboratory models of stratified mosaics and fresco paintings, specimens extracted from a neolithic excavation site in Catalhoyuk, Turkey, and specimens measured at the medieval Eglise de Saint Jean-Baptiste in Vif, France. Preparatory spectroscopic studies of various composite materials, including lime, gypsum and clay plasters are presented to enhance the interpretation of results and with the intent to aid future computer simulations of the TPI of stratified architectural material. The breadth of the sample range is a demonstration of the cultural demand and public interest in the life history of buildings. The results are an illustration of the potential role of TPI in providing both a chronological history of buildings and in the visualization of obscured wall paintings and mosaics.

Digital treatment of images has been widely used in many different fields, including astrophysical, medical, geographical and military research. In the last years, digital elaboration of the images has also been used in the field of the Cultural Heritage conservation. Many paintings, especially old ones, suffer from breaks in substrate, paint, or varnish. These patterns are usually called cracks or craquelure and can be caused by aging, drying, and mechanical factors. The appearance of cracks on paintings deteriorates the perceived image quality. However, one can use digital image processing techniques to detect and eliminate the cracks on digitized paintings. Such a "virtual" restoration can provide clues to art historians, museum curators and the general public on how the painting would look like in its initial state, i.e., without the cracks. An integrated methodology for the detection and removal of cracks on digitized paintings is presented in this paper.

Starting from the standard colorimetry, as defined by the International Commission on Illumination - CIE, we propose an enhanced approach to add near UV and near IR sides to the usual visible electromagnetic spectrum, extending standard XYZ colorimetric coordinate to 7 values, calculated with a revision of the Color Matching Functions (CMF) that we called Hypercolor Matching Functions (HMF). We used a modified digital reflex camera and a set of optical filters to realize such a system and we measured 7 band based colorimetric distances among several pigments, that, compared to distances calculated in the XYZ space, resulted into a better and more reliable separation among reflectance spectra.

The non-destructive analysis of works of art and more specifically the paintings with the aim of a non-ambiguous identification of their components and the understanding of the techniques of the artists still remains a challenge. The aim of our research is to elaborate a purely optical way for this identification, based on the exclusive use of the intrinsic characteristic optical parameters of the components, instead the derived parameters presently commonly used, depending on several other parameters (morphology, environment...). The approach we propose is based on the resolution of the RTE using the 4-Flux approximation, combined with the Mie theory, allowing the identification of the pigments via the spectrum of their complex optical index entered into the model via a database. The key point of this approach is the index data bank. We report in this communication one the method's crucial steps: the determination of the intrinsic optical index of pigments under the form of grains of micrometric size. This step is far from trivial and presents many difficulties that are not completely solved. This is one of the reasons why a more rigorous analysis of the paintings has not been up to now developed. We illustrate this problem with a red pigment: vermillion randomly dispersed at low concentration in a transparent polymer. The morphology of the sample is well characterized (thickness, concentration, size and dispersion of the pigments, surface roughness) as well as the index of the matrix. We use the same approach and model as presented above, applied this time to the calculation of the complex index of the pigments. The model is supposed to account for the diffuse flux and the specular flux, both measured on our samples, by spectrophotometry with an integrating sphere in the visible spectral range 400-800 nm. This resolution allows determining independently the coefficients of scattering and absorption of the pigment, which are finally related to the complex index of refraction through Mie's Theory.

Multispectral and hyperspectral imaging are efficient methods of measuring spectral reflectance at high spatial resolution. This non-invasive technique has been applied to the imaging of paintings over the last 20 years. PRISMS (Portable Remote Imaging System for Multispectral Scanning) was designed specifically for imaging wall paintings. Optical Coherence Tomography (OCT) is a low coherence interferometric technique capable of fast non-invasive imaging of subsurface microstructure. This paper shows the first application of in situ OCT imaging of a wall painting. The combination of PRISMS and OCT gives information on the varnish and paint layer structure, pigment identification, the state of degradation of the paint and varnish layers and informing curators on the painting schemes and techniques.

Optical coherence tomography (OCT) is a fast non-contact and non-invasive technique for examination of objects consisting of transparent or semitransparent layers. Since it is a useful tool for inspection of Hinterglasmalerei paintings, the aim of the experiment was to explore its feasibility for monitoring of the consolidation process, which plays the most important role in the conservation treatment of such artefacts.

This paper will introduce a new application of Optical Coherence Tomography (OCT) to the monitoring of vulnerability of rock art monuments in-situ. The porosity of the host rock is an important factor affecting the susceptibility of rock art monuments to decay. Pore characteristics of rocks are one of the main factors that control the intensity of physical deterioration. OCT has successfully been applied to paintings and archaeological objects, including geological materials, to produce cross sectional images non-invasively. The stack of cross sectional images can be rendered as a volume to visualise the structure in depth over an extended area. Preliminary studies show that it can directly image the pores and subsurface structure to within 500microns of the surface depending on lithology. This study aims to analyse this stack of cross sectional images computationally to enable the description of the pore space distribution which will be compared with spatially resolved NMR porosity measurement for the samples.

We present the application of the shape-from-silhouette algorithm to reconstruct the 3D profile of handworks from a set of X-ray absorption images taken at different angles around the object. The acquisition technique is similar to tomography, but the number of images that are required to reconstruct the 3D appearance is very low compared to tomography, therefore the acquisition time is substantially reduced. Some reference points are placed on a structure corotating with the object and are acquired on the images for calibration and registration. The shape-from-silhouette algorithm gives finally the 3D appearance of the object. We present the analysis of a tin pendant from the Venetic area, VI century b.C., that was completely hidden by corrosion products and solid ground at the moment of the retrieval. The 3D reconstruction shows that the pendant is a very elaborated piece, with two embraced figures that were completely invisible before restoration.

A preliminary investigation has taken place employing Digital Holographic Speckle Pattern Interferometry (DHSPI) in order to assess the effect of handling and transportation on canvas paintings. Canvas dummies were used on a series of measurements on a transport simulator which allows reproducible simulation of any transport logs in the laboratory. A number of cycles of controlled vibrations were applied on the samples and after each cycle a measurement with DHSPI was taken to monitor the behavior of the samples while increasing the vibration loading and also to record the conditions under which the first crack appears. The transport simulations in combination with DHSPI monitoring revealed the amplitude of oscillation where the first cracks appear on new canvas paintings and also the way these cracks grow. During the tests it was also feasible to locate areas at risk of future deterioration.

Infrared digital holograms of different statuettes are acquired. For each object, a sequence of holograms is recorded rotating the statuette with an angular step of few degrees. The holograms of the moving objects are used to compose dynamic 3D scenes that, then, are optically reconstructed by means of spatial light modulators (SLMs) using an illumination wavelength of 532 nm. This kind of reconstruction allows to obtain a 3D imaging of the statuettes that could be exploited for virtual museums.

A non-invasive and non-contact optical method for tracking overall and local deformations of canvas painting is presented. The technique was tested on a model painting on canvas with inhomogeneities introduced by infilling gaps, mending tears, and applying patches on the reverse of the canvas. The deformation of the sample was induced by changes of relative humidity. The feasibility of 3D Digital Image Correlation technique for evaluation of conservation methods is discussed.

In this paper a new 3D measurement system along with the study on 3D printing technology is presented from the perspective of quality of reproduction. In the first part of the paper the 3DMADMAC SPECTRAL system which integrates 3D shape with additional color and angular reflectance measurement capabilities is presented. The shape measurement system is based on structured light projection with the use of a DLP projector. The 3D shape measurement method is based on sinusoidal fringes and Gray codes projection. Color is being measured using multispectral images with a set of interference filters to separate spectral channels. Additionally the set up includes an array of compact light sources for measuring angular reflectance based on image analysis and 3D data processing. All three components of the integrated system use the same grayscale camera as a detector. The purpose of the system is to obtain complete information about shape, color and reflectance characteristic of measured surface, especially for cultural heritage objects - in order to use their models in 3D copying application. In the second part of the paper the 3D printing technology will be tested on artificial objects as well as on real measured cultural heritage ones. Testing on artificial objects allows to assess measurement and color accuracy of reproduction by selected 3D printing technology. Testing on real objects sheds some light on how current 3D printing technology can be applied into cultural heritage.

Since several years our laboratory in ENEA Frascati Research Center is involved in development of laser scanners for Cultural Heritage investigation problems. Actually the best result obtained in this field by our laboratory is a 3D Red Green Blue Laser scanner, called RGB-ITR: the main feature of this scanner, further then measuring distances (up to 20m with a sub-millimetric resolution), is the ability to capture remotely color information by three calibrated laser sources: this information is collected for each point sampled by the instrument and is not affected by external light sources' influence. Moreover the ability to acquire color and distance information at the same time and for each point decrease drastically the post-production pipeline of a complete mesh. In this work the results of a complete scan of S. Peter Martyr in Rieti are shown, highlighting the efficiency and robustness of color calibration algorithms introduced for a correct color representation.

The design of a compact spectrometer for analysis of artworks is presented. Its operation is based on the use of a variable transmission filter associated with an array detector. The instrument allows the measurement of the spectral reflectance factor and combines the acquisition of data in a continuous spectrum with the small dimension that is of primary importance for in-situ spectral imaging.

In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (▵E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

The increasing deterioration of panel paintings can be due to physical processes that take place during exhibition or transit, or as a result of temperature and humidity fluctuations within a building, church or museum. In response to environmental alterations, a panel painting can expand or contract and a new equilibrium state is eventually reached. These adjustments though, are usually accompanied by a change in shape in order to accommodate to the new conditions. In this work, a holographic method for detecting detached regions and micro-cracks is described. Some of these defects are confirmed by Thermographic Signal Reconstruction (TSR) technique. In addition, Pulsed Phase Thermography (PPT) and Principal Component Thermography (PCT) allow to identify with greater contrast two artificial defects in Mylar which are crucial to understand the topic of interest: the discrimination between defect materials. Finally, traditional contact ultrasounds applications, are widely applied for the evaluation of the wood quality in several characterization procedures. Inspecting the specimen from the front side, the natural and artificial defects of the specimen are confirmed. Experimental results derived by the application of the integrated methods on an Italian panel painting reproduction, called The Angel specimen, are presented. The main advantages that these techniques can offer to the conservation and restoration of artworks are emphasized.

When we buy an artwork object a certificate of authenticity contain specific details about the artwork. Unfortunately, these certificates are often exchanged between similar artworks: the same document is supplied by the seller to certificate the originality. In this way the buyer will have a copy of an original certificate to attest that the "not original artwork" is an original one. A solution for this problem would be to insert a system that links together the certificate and a specific artwork. To do this it is necessary, for a single artwork, to find unique, unrepeatable, and unchangeable characteristics. In this paper we propose a new lithography certification based on the color spots distribution, which compose the lithography itself. Due to the high resolution acquisition media available today, it is possible using analysis method typical of speckle metrology. In particular, in verification phase it is only necessary acquiring the same portion of lithography, extracting the verification information, using the private key to obtain the same information from the certificate and confronting the two information using a comparison threshold. Due to the possible rotation and translation it is applied image correlation solutions, used in speckle metrology, to determine translation and rotation error and correct allow to verifying extracted and acquired images in the best situation, for granting correct originality verification.

A mobile hand held battery powered sensor based on fringe projection technique for preservation of fossil traces and archaeological excavations was developed. It consists of a projector and two cameras and covers a measuring field of about 240 mm x 175 mm x 160 mm. The core time for data acquisition is 0.34 s and the final result of a 3D point cloud is obtained in less than five seconds. Errors due to movements of the sensor are detected and can be swept out. The sensor allows the capturing of 3D data of the observed surface together with colour information. It was successfully applied at fossil find of traces of a dinosaur at rock layers from Triassic. 3D reconstruction of a part of the excavation was realized including the determination of the depth of traces.

A new portable spectral imaging system is herein presented capable of acquiring images of high resolution (2MPixels) ranging from 380 nm up to 950 nm. The system consists of a digital color CCD camera, 15 interference filters covering all the sensitivity range of the detector and a robust filter changing system. The acquisition software has been developed in "LabView" programming language allowing easy handling and modification by end-users. The system has been tested and evaluated on a series of objects of Cultural Heritage (CH) value including paintings, encrusted stonework, ceramics etc. This paper aims to present the system, as well as, its application and advantages in the analysis of artworks with emphasis on the detailed compositional and structural information of layered surfaces based on reflection & fluorescence spectroscopy. Specific examples will be presented and discussed on the basis of system improvements.

3D optical techniques are proven to be useful for the study of the artwork's surface morphology because they allow noncontact and noninvasive measurements. Detailed topographic analysis of the surface including a quantitative evaluation of defects related to the painting layers can be performed by means of holographic conoscopy on a micron scale. Moreover, artwork surfaces can be examined with suitable 2D optical techniques in the IR range to investigate defects at a subsurface level. In particular, thermography in the Mid-IR band 3-5 micron allows the detection and spatial mapping at a suitable resolution of the delamination of painted layers. An integrated model of the surface-subsurface defect distribution can be obtained by superimposing the results of the two above techniques, for a more effective analysis and monitoring of the delamination decay typology according to the specific case study. The delamination of organic paint layers from inorganic support is a decay that affects many wall paintings based on both traditional (oil and tempera) and synthetic media (acrylic and vinyl copolymers). Defining the factors that cause delamination, finding out strategies to restore the adhesion between paint layers and support, and monitoring the restoration intervention are fundamental conservation objectives. This paper investigates the feasibility of a joint use of holographic conoscopy and IR thermography for exploring the delamination decay typology of ad hoc laboratory samples. Set up includes a scanning micro-profilometer, and a thermal PtSi camera with a controlled IR source to provide heating stimulation.

PRISMS (Portable Remote Imaging System for Multispectral Scanning) is a multispectral/hyperspectral imaging system designed for flexible in situ imaging of wall paintings at high resolution (tens of microns) over a large range of distances (less than a meter to over ten meters). This paper demonstrates a trial run of the VIS/NIR (400-880nm) component of the instrument for non-invasive imaging of wall paintings in situ. Wall painting panels from excavated Tang dynasty (618- 907AD) tombs near Xi'an were examined by PRISMS. Pigment identifications were carried out using the spectral reflectance obtained from multispectral imaging coupled with non-invasive elemental analysis using a portable XRF.