Perceptual coding for 3D reconstruction

A primary issue in 3D reconstruction is the realtime efficacy of different coding methods for the multiple decisions among competing 3D solutions. A common model framework making such coding decisions is the boundary limited drift-diffusion model, which has been developed in parallel in various branches of science from quantum physics to economics. A common property of all such models is the linear increase in variance of the diffusion processes over time, implying an inability to focus on the current information in the environment, and the inevitability of a forced random decision in the absence of any reliable evidence. We have developed an alternative, more plausible model framework for Bayesian information accumulation that solves both problems and provides an accurate account of many features of context effects in human 3D reconstruction performance. © 2011 IEEE

Printing with tonalli: Reproducing featherwork from precolonial Mexico using structural colorants

Two of the most significant cases of extant 16th-century featherwork from Mexico are the so-called Moctezuma’s headdress and the Ahuizotl shield. While the feathers used in these artworks exhibit lightfast colors, their assembly comprises mainly organic materials, which makes them extremely fragile. Printed media, including books, catalogs, educational materials, and fine copies, offer an accessible means for audiences to document and disseminate visual aspects of delicate cultural artifacts without risking their integrity. Nevertheless, the singular brightness and iridescent colors of feathers are difficult to communicate to the viewer in printed reproductions when traditional pigments are used. This research explores the use of effect pigments (multilayered reflective structures) and improved halftoning techniques for additive printing, with the objective of enhancing the reproduction of featherwork by capturing its changing color and improving texture representation via a screen printing process. The reproduced images of featherwork exhibit significant perceptual resemblances to the originals, primarily owing to the shared presence of structural coloration. We applied structure-aware halftoning to better represent the textural qualities of feathers without compromising the performance of effect pigments in the screen printing method. Our prints show angle-dependent color, although their gamut is reduced. The novelty of this work lies in the refinement of techniques for printing full-color images by additive printing, which can enhance the 2D representation of the appearance of culturally significant artifact

A Multidisciplinary Study of the Tongerlo Last Supper and its Attribution to Leonardo Da Vinci’s Second Milanese Studio

This article presents the findings from a two-year study of the Last Supper canvas in the Abbey of Tongerlo, Belgium, including a detailed review of its provenance as well as a multispectral study conducted by IMEC and IPARC. The study used a composite multidisciplinary approach, with traditional connoisseurship and literary research augmented by scientific examination, including IRR (Infrared Reflectography). The article argues that based on the available evidence, the Tongerlo Last Supper was produced in Leonardo’s Milanese workshop between 1507 and 1509, as a collaborative project involving the Leonardeschi Giampietrino, Andrea Solario, and Marco d’Oggiono under Leonardo’s supervision. Furthermore, the infrared spectography scans suggest that the face of John in the painting was painted by Leonardo himself.Questo articolo presenta i risultati di uno studio durato due anni della tela raffigurante l'Ultima Cena nell'Abbazia di Tongerlo, in Belgio. Vi è cui una revisione dettagliata della sua provenienza e uno studio multispettrale condotto da IMEC e IPARC. Lo studio ha utilizzato un approccio multidisciplinare, in cui conoscenza tradizionale e ricerca letteraria sono integrate dall'esame scientifico, in particolare dall'IRR (Riflettografia a infrarossi). Nell'articolo si sostiene che, sulla base delle prove disponibili, l'Ultima Cena di Tongerlo fu prodotta nella bottega milanese di Leonardo tra il 1507 e il 1509, come progetto collaborativo che coinvolse Leonardeschi Giampietrino, Andrea Solario e Marco d'Oggiono sotto la supervisione di Leonardo. Le scansioni effettuate con spettrografia a infrarossi, inoltre, suggeriscono che il volto di Giovanni nel dipinto sia stato dipinto da Leonardo stesso

On the use of in-situ spectroscopic techniques for the study of the provenance of historic ivories

Current protocols for ivory identification are destructive and resource-consuming. The current investigation aimed to develop a classification model based on insitu spectroscopic techniques combined with chemometrics to discriminate between Asian and African ivory on the field. The spectroscopic techniques utilized were Fourier-transform Infrared Spectroscopy (FT-IR) and Fiber Optics Reflectance Spectroscopy (FORS) in the near-infrared region (NIR) combined with chemometric methods of Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA). Historic ivories were successfully classified through FT-IR with PCA, and FORS-NIR with PLS-DA, resulting in a True Prediction Rate from 93.028% to 99.020% in African samples and 93.333% to 100.000% in Asian samples. The study demonstrated the potential of FORS-NIR as an investigative tool for ivory investigations. It also illumined the possibility of ivory trade networks of African ivory with the East, and a scientific perspective of the more desirable mechanical properties of African ivory over Asian ivory; Resumo: Os protocolos atuais para identificação de marfim são destrutivos e consomem muitos recursos. A presente investigação teve como objetivo desenvolver um modelo de classificação baseado em técnicas espectroscópicas in situ combinadas com quimiometria para discriminar entre marfim asiático e africano no campo. As técnicas espectroscópicas utilizadas foram a espectroscopia de infravermelho com transformada de Fourier (FT-IR) e espectroscopia de reflectância de fibra óptica (FORS) na região do infravermelho próximo (NIR) combinada com métodos quimiométricos de análise de componentes principais (PCA) e análise discriminante de quadrados mínimos parciais (PLS-DA). Marfins históricos foram classificados com sucesso através de FT-IR com PCA e FORSNIR com PLS-DA, resultando em uma Taxa de Previsão Verdadeira de 93,028% a 99,020% em amostras africanas e 93,333% a 100,000% em amostras asiáticas. O estudo demonstrou o potencial do FORS-NIR como uma ferramenta investigativa para investigações de marfim. Também iluminou a possibilidade de redes de comércio de marfim africano com o Oriente e uma perspectiva científica das propriedades mecânicas mais desejáveis do marfim africano sobre o marfim asiático

The English Landscapes in the Seventeenth Century

Relatively few critical studies have been written concerning the English landscape genre in the seventeenth century, not due to a lack of production or interest in the genre, but rather as a result of an anachronistic definition that is the product of eighteenth century artistic discourse. In contrast, I explore landscape as it was defined in contemporaneous seventeenth-century works and literature. Rather than a singular definition, I propose that the genre in the seventeenth century was marked by multiple iterations, each of which corresponded to shifting perceptions concerning the role of land in the culture, economy and politics of England. As such, the iterations explored herein range from the highly symbolic to the topographic, the ideal and combinations of the three, each representing different aspects of the discursive relationship to the English land over the century. Much like the English language, the landscapes of this period incorporated not only native traditions and values but also translated established variations of the genre from Northern and Southern European artistic discourses into the English context. Given the iterability of the genre, I explore landscape within a pre-determined set of limits: temporal (late sixteenth to late seventeenth century), geographic (England), thematic (symbolic, topographic, ideal and estate landscapes) and formal (painting, drawing and printmaking). Unlike other explorations of the English landscape that apply strict, often anachronistic definitions of the genre, I explore landscape from a broad perspective, one that not only seeks out the aesthetic frameworks that shaped it, but the economic, social and political discourses that gave the genre significance in the period

Image, Knife, and Gluepot

"In this ingenious study, Kathryn Rudy takes the reader on a journey to trace the birth, life and afterlife of a Netherlandish book of hours made in 1500. Image, Knife, and Gluepot painstakingly reconstructs the process by which this manuscript was created and discusses its significance as a text at the forefront of fifteenth-century book production, when the invention of mechanically-produced images led to the creation of new multimedia objects. Rudy then travels to the nineteenth century to examine the phenomenon of manuscript books being pillaged for their prints and drawings: she has diligently tracked down the dismembered parts of this book of hours for the first time. Image, Knife, and Gluepot also documents Rudy’s twenty-first-century research process, as she hunts through archives while grappling with the logistics and occasionally the limits of academic research. This is a timely volume, focusing on questions of materiality at the forefront of medieval and literary studies. Beautifully illustrated throughout, its use of original material and its striking interdisciplinary approach, combining book and art history, make it a significant academic achievement. Image, Knife, and Gluepot is a valuable text for any scholar in the fields of medieval studies, the history of early books and publishing, cultural history or material culture. Written in Rudy’s inimitable style, it will also be rewarding for any student enrolled in a course on manuscript production, as well as non-specialists interested in the afterlives of manuscripts and prints. The Royal Society of Edinburgh has generously contributed to this Open Access publication. Due to the number and quality of the images in this book, we have provided the option of a more expensive hardback edition, printed on the best quality paper available, in order to present the images as clearly and beautifully as possible. We hope this range of options — the freely available PDF, HTML and XML editions; the economically priced EPUB, MOBI and paperback editions; and the more expensively printed hardback — will satisfy everyone. Furthermore the HTML edition allows readers to magnify the images of the manuscripts displayed in the book.

The Functions of Portolan Maps: An evaluation of the utility of manuscript nautical cartography from the thirteenth through sixteenth centuries

In the thirteenth century, following the expansion of seafaring city-states and kingdoms in the Mediterranean, a new form of cartography emerged, known as portolan charts. These maps, more secular and scientific than earlier cartographic genres, were produced between the thirteenth and seventeenth centuries, primarily in the western Mediterranean. While portolan charts and atlases have been studied since the nineteenth century, they remain enigmatic. One of the most important questions about them has been: ‘what was their function’? Most scholars have argued that they were fundamentally utilitarian maps, used for navigation. This thesis challenges that theory, and proposes that portolan maps were not navigational. To critically assess the function of portolan maps, the first chapter evaluates their methods of construction, as determined through an analysis of primary sources, and an original archaeological reconstruction of a portolan chart. The second chapter presents seven case studies of charts, atlases, and their makers, to explore the cartographers’ output, the specific functions of their maps, and how they relate to the genre as a whole. The third chapter analyses the contemporary documentary and literary evidence to gain a better understanding of the economic market for portolan maps. The fourth chapter evaluates their functions, in two parts: the first discusses how the maps could have been used on ships, how they changed over time, and investigates the practical utility of their toponymy and hydrography. The second part explores their alternative functions, which were as administrative and encyclopaedic maps, spiritual and scholarly maps, and aesthetic objets d’art. Although some evidence suggests portolan maps were used at sea, it is largely circumstantial and unspecific. The evaluation of their construction, specific functions, the output of cartographers, and their practical utility, instead indicates that portolan maps were not navigationally useful, but embodied number of other purposes

Heritage in the Clouds: Englishness in the Dolomites

Guided by the romantic compass of Byron, Ruskin and Turner, Victorian travellers to the Dolomites sketched through their wanderings in the mountainous backdrop of Venice a cultural ‘Petit Tour’ of global significance. As they zigzagged across a debatable land consumed by competing frontiers, Victorians discovered a unique geography characterized by untrodden peaks and unfrequented valleys. This landscape blended aesthetic, scientific and cultural values utterly different from those engendered by the bombastic conquests of the Western Alps achieved during the ‘Golden Age of Mountaineering’. Filtered through the cultivated lens of the Venetian Grand Tour, their encounter with the Dolomites is marked by a series of distinct cultural practices that paradigmatically define what I call the ‘Silver Age of Mountaineering’. These cultural practices, magnetized by symbols of Englishness, reveal a range of geographic concerns that are more ethnographic than imperialistic, more feminine than masculine, more artistic than sportive – rather than racing to summits, the Silver Age is about rambling, rather than conquering peaks, it is about sketching them in fully articulated interaction with the Dolomite landscape. Through these practices, the Dolomite Mountains came to be known in England as ‘Titian Country’, spurring among Victorian travellers the sentimental drive to ramble in the backgrounds of Titian’s paintings. Freed from their historical conditions and rehashed in different discursive patterns, these symbols of Englishness re-emerge through a history collapsed through geography: a heritage that is subtly, if controversially, exploited today in the wake of the recent inscription of the Dolomites onto the UNESCO World Heritage List

Alessandro Moretto and the Decomposition of the Painter\u27s Art in Renaissance Brescia

The religious paintings of Alessandro Moretto, also known as Moretto da Brescia, have endured a mixed reception from modern art historians. Certain of his paintings are routinely praised for their supposedly unaffected naturalism and their attention to the mundane details of lived experience, while many more of his altarpieces, chapel laterals, and domestic religious images have been criticized for their compositional incoherence and their overly obvious references to other artworks. Through four focused case studies covering the full extent of his career and including both domestic and liturgical images, this dissertation interrogates the relationship between Moretto’s compositional disintegration and the subject matter of the pictures where this lack of integrity is most pronounced. Moretto’s images concerning Christ’s body frequently pursued a strategy of pictorial incoherence that forcefully separated the recognition and interpretation of Christ’s physical form from a painting’s perceived ability to make absent bodies present for a beholder. In each of the cases examined, Moretto is shown to have set his pictures in opposition to one or more images—often well-known monuments of High Renaissance art—in which pictorial integrity signaled a potentially problematic relationship between the image and its maker. Contemporary publications that encouraged the discontinuous reorganization of an authored text are also identified as having encouraged the piecemeal appearance of Moretto’s highly referential pictures. Moretto’s fractured compositions distanced his paintings from the creative activities of nature and of God, making the works unsuitable as proxies for bodies but allowing them to facilitate a more complex contemplation of Christ’s body and its meaning in the era of pre-Tridentine Catholic reform