Evaluation and improvement of the workflow of digital imaging of fine art reproduction in museums

Fine arts refer to a broad spectrum of art formats, ie~painting, calligraphy, photography, architecture, and so forth. Fine art reproductions are to create surrogates of the original artwork that are able to faithfully deliver the aesthetics and feelings of the original. Traditionally, reproductions of fine art are made in the form of catalogs, postcards or books by museums, libraries, archives, and so on (hereafter called museums for simplicity). With the widespread adoption of digital archiving in museums, more and more artwork is reproduced to be viewed on a display. For example, artwork collections are made available through museum websites and Google Art Project for art lovers to view on their own displays. In the thesis, we study the fine art reproduction of paintings in the form of soft copy viewed on displays by answering four questions: (1) what is the impact of the viewing condition and original on image quality evaluation? (2) can image quality be improved by avoiding visual editing in current workflows of fine art reproduction? (3) can lightweight spectral imaging be used for fine art reproduction? and (4) what is the performance of spectral reproductions compared with reproductions by current workflows? We started with evaluating the perceived image quality of fine art reproduction created by representative museums in the United States under controlled and uncontrolled environments with and without the presence of the original artwork. The experimental results suggest that the image quality is highly correlated with the color accuracy of the reproduction only when the original is present and the reproduction is evaluated on a characterized display. We then examined the workflows to create these reproductions, and found that current workflows rely heavily on visual editing and retouching (global and local color adjustments on the digital reproduction) to improve the color accuracy of the reproduction. Visual editing and retouching can be both time-consuming and subjective in nature (depending on experts\u27 own experience and understanding of the artwork) lowering the efficiency of artwork digitization considerably. We therefore propose to improve the workflow of fine art reproduction by (1) automating the process of visual editing and retouching in current workflows based on RGB acquisition systems and by (2) recovering the spectral reflectance of the painting with off-the-shelf equipment under commonly available lighting conditions. Finally, we studied the perceived image quality of reproductions created by current three-channel (RGB) workflows with those by spectral imaging and those based on an exemplar-based method

Implementation of Wiener Algorithm for Spectral Reflectance Reconstruction of 3 and 6 Channel Images

Wiener estimation is a widely used technique for the spectral reflectance reconstruction of colored objects. In our study the reflectance estimation of 3-channel images acquired using traditional RGB camera was compared with that of 6-channel images captured by a modified 6-channel camera. 240 patches of ColorChecker DC Chart were used for training and testing of the models.Their performance was assessed via quality metrics PSNR, RMSE and CIE DE2000 based on the reconstructed and spectrophotometrically measured reflectance values. Compared to the 3-channel models, 6-channel models in general provided better results. Lowest color difference CIE DE2000 was obtained when using 10 calculation terms in the 3-channel algorithm and 13 terms in the 6-channel. Best reconstruction models, i.e. lowest CIE DE2000 and RMSE and highest PSNR values, were found for the skin and neutral tones while the performance was the poorest with the saturated color patches. The obtained results can be of use in various practical applications, such as in a printing workflow with high precision color rendering or for accurate digitization of paintings and other works of art

Systems evaluation for computer graphics rendering of the total appearance of paintings

One of the challenges when imaging paintings is recording total appearance, that is, the object\u27s color, surface microstructure (gloss), and surface macrostructure (topography). In this thesis, various systems were used to achieve this task, and a psychophysical paired comparison experiment was conducted to evaluate their performance. A pair of strobe lights arranged at 60° from the normal on either side of the painting captured color information where the strobes produced either directional or diffuse illumination geometry. By adding a third strobe, arranging them 120° apart annularly, and cross polarizing, diffuse color and surface normal maps were measured. A fourth strobe was added and the four lights were rearranged 90° apart annularly, capturing similar data. This system was augmented by two scanning linear light sources arranged perpendicularly, facilitating the measurement of spatially varying BRDF and specular maps. A laser scanner was used to capture surface macrostructure and was combined with the diffuse color maps from the four-light configuration. Finally, a dome illumination system was used with software developed by Conservation Heritage Imaging to produce color maps. In all, eight different configurations were achieved and used to image three small paintings with a range of appearance attributes. Twenty-five naive observers compared computer-graphic renderings to the actual painting and judged similarity in terms of total appearance, gloss/shininess, texture, and color. Although the rankings varied with painting, two general trends emerged. First, the four-light configuration with or without the independent laser scanning produced images visually equivalent to conventional strobe illumination. Second, diffuse illumination was always ranked lowest

MetaSpace II: Object and full-body tracking for interaction and navigation in social VR

MetaSpace II (MS2) is a social Virtual Reality (VR) system where multiple users can not only see and hear but also interact with each other, grasp and manipulate objects, walk around in space, and get tactile feedback. MS2 allows walking in physical space by tracking each user's skeleton in real-time and allows users to feel by employing passive haptics i.e., when users touch or manipulate an object in the virtual world, they simultaneously also touch or manipulate a corresponding object in the physical world. To enable these elements in VR, MS2 creates a correspondence in spatial layout and object placement by building the virtual world on top of a 3D scan of the real world. Through the association between the real and virtual world, users are able to walk freely while wearing a head-mounted device, avoid obstacles like walls and furniture, and interact with people and objects. Most current virtual reality (VR) environments are designed for a single user experience where interactions with virtual objects are mediated by hand-held input devices or hand gestures. Additionally, users are only shown a representation of their hands in VR floating in front of the camera as seen from a first person perspective. We believe, representing each user as a full-body avatar that is controlled by natural movements of the person in the real world (see Figure 1d), can greatly enhance believability and a user's sense immersion in VR.Comment: 10 pages, 9 figures. Video: http://living.media.mit.edu/projects/metaspace-ii

Advances in multispectral and hyperspectral imaging for archaeology and art conservation

Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed

Assessment of multispectral and hyperspectral imaging systems for digitisation of a Russian icon

In a study of multispectral and hyperspectral reflectance imaging, a Round Robin Test assessed the performance of different systems for the spectral digitisation of artworks. A Russian icon, mass-produced in Moscow in 1899, was digitised by ten institutions around Europe. The image quality was assessed by observers, and the reflectance spectra at selected points were reconstructed to characterise the icon’s colourants and to obtain a quantitative estimate of accuracy. The differing spatial resolutions of the systems affected their ability to resolve fine details in the printed pattern. There was a surprisingly wide variation in the quality of imagery, caused by unwanted reflections from both glossy painted and metallic gold areas of the icon’s surface. Specular reflection also degraded the accuracy of the reconstructed reflectance spectrum in some places, indicating the importance of control over the illumination geometry. Some devices that gave excellent results for matte colour charts proved to have poor performance for this demanding test object. There is a need for adoption of standards for digitising cultural heritage objects to achieve greater consistency of system performance and image quality.This article arose out of a Short-Term Scientific Mission (STSM) conducted by Tatiana Vitorino when visiting University College London during a 2-week period in late October 2015. The research was carried out under the auspices of the European COST Action TD1201 Colour and Space in Cultural Heritage (COSCH). The project website is at http://www.cosch.info. Under the COST rules, TV received funding for travel and accommodation expenses, and all coauthors were able to claim travel expenses to attend the subsequent COSCH project meeting. No other funding was received from COSCH for labour or equipment and all work was done on a voluntary pro bono basis.info:eu-repo/semantics/publishedVersio

Pictures in Your Mind: Using Interactive Gesture-Controlled Reliefs to Explore Art

Tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape, and surface textures are directly perceivable. Although often created for blind and visually impaired (BVI) people, a wider range of people may benefit from such multimodal material. However, some reliefs are still difficult to understand without proper guidance or accompanying verbal descriptions, hindering autonomous exploration. In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that can be operated directly with the hands on relief surfaces during tactile exploration. The interactively explorable, location-dependent verbal and captioned descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to online resources, or as a kiosk installation at public places. We present a working prototype, discuss design decisions, and present the results of two evaluation studies: the first with 13 BVI test users and the second follow-up study with 14 test users across a wide range of people with differences and difficulties associated with perception, memory, cognition, and communication. The participant-led research method of this latter study prompted new, significant and innovative developments

An Analysis of the art image interchange cycle within fine art museums

The art image interchange cycle is the procedure carried out by fine art museums in reproducing fine artwork --starting with the imaging of the original work, then digital processing, and lastly, repurposing for output to achieve a high-quality replica in a range of possible media. There are many areas of importance within this process, such as digital image processing, standardization, test targets use, and color management. This research has sought to analyze the fine art image interchange through understanding the background areas and how they apply, as well as benchmarking what museums are already doing with the intention of improving and standardizing the process. Upon completion of an adequate background study of the literature (concentrated on color management theory, test targets use, and fine art reproduction) this research focused on four main areas. First, a review of international standards was established and how they can be used to benefit museums. Second, a review of test targets was conducted and how best they can be implemented in fine art reproduction. Third, a number of museum workflows were benchmarked and documented - a workflow experiment was created and implemented for documentation purposes (and future image quality analysis). Lastly, a case study was conducted of a local fine art museum\u27s process of creating a fine art catalog, to better understand an average museum\u27s fine art image interchange. The research concluded that the practice of standardization could be improved within museums. As far as test targets, there was a large range of understanding and use. The benchmarking of three museums was completed, and it was determined that the process of documenting workflow was a difficult task to have implemented. Lastly, in x the case study, much was gained through the interviews, placing a great importance on communication, planning, and standardization

Imaging at the National Gallery of Art, Washington D.C.

This report provides the description of a recent fine art spectral imaging session at the National Gallery of Art, Washington D. C. This report also includes subsequent evaluation of the performance of our multi-channel visible-spectral imaging (MVSI) system. The multi-band channels analyzed in this report were obtained using a monochrome CCD and a liquid-crystal tunable filter (LCTF) capturing 31 narrow-band channels. The results showed the effectiveness of our designed spectral imaging when used at a museum environment to capture spectral imaging of fine art paintings. Furthermore, we also verified the dependence of the performance on the selection of the characterization target. Various combinations of imaged targets were used to generate the transformation. Among our characterization target combinations, the one that includes GretagMacbeth ColorChecker DC combined with a target of blue pigments was selected considering its impact on spectral estimation performance in reconstructing painting pigments (Gamblin target). This result points directions to a design of a universal target for painting spectral imaging and estimation