Virtual Rephotography: Novel View Prediction Error for 3D Reconstruction

The ultimate goal of many image-based modeling systems is to render photo-realistic novel views of a scene without visible artifacts. Existing evaluation metrics and benchmarks focus mainly on the geometric accuracy of the reconstructed model, which is, however, a poor predictor of visual accuracy. Furthermore, using only geometric accuracy by itself does not allow evaluating systems that either lack a geometric scene representation or utilize coarse proxy geometry. Examples include light field or image-based rendering systems. We propose a unified evaluation approach based on novel view prediction error that is able to analyze the visual quality of any method that can render novel views from input images. One of the key advantages of this approach is that it does not require ground truth geometry. This dramatically simplifies the creation of test datasets and benchmarks. It also allows us to evaluate the quality of an unknown scene during the acquisition and reconstruction process, which is useful for acquisition planning. We evaluate our approach on a range of methods including standard geometry-plus-texture pipelines as well as image-based rendering techniques, compare it to existing geometry-based benchmarks, and demonstrate its utility for a range of use cases.Comment: 10 pages, 12 figures, paper was submitted to ACM Transactions on Graphics for revie

Repetition, movement and the visual ontographies of urban rephotography: learning from Smoke (1995)

none2noEngaging with a scene of the iconic movie Smoke (by Wayne Wang, 1995) in which a rephotographic project is sensitively elicited, this paper addresses the technique of repeat photography to contribute to methodological debates that have arisen within the nascent ‘Mobility and Humanities’ subfield. Through a humanistic perspective, the paper reviews and expands the nexus between mobility, photography and the urban by comparing the technique with three methodological issues: the blurring of supposed binaries, such as traditional/innovative, static/moving and fast/slow; the possibility of grasping the mobilities of the world in a post-human vein; and the opportunity to also consider techniques as sites for reflection. To address these issues, the paper draws from philosophies of movement, post-phenomenological and object-oriented stances and visual and urban cultural geographies. With reference to the urban realm, this paper proposes three perspectives on rephotography, namely (1) rephotography as a practice of slow and rhythmic attunement with circumstantial spacetimes moving backwards and forwards; (2) rephotography as a visual ontography that displaces the human and opens up space for the apprehension of the agency and mobility of things; and (3) rephotography as a continual process of activation of moving gazes on cities and their imaginaries.noneTania Rossetto; Alberto VanoloRossetto, Tania; Vanolo, Albert

Exegesis : photographs and place

Photographs are used to reinforce arguments about our history, our culture, and our identity. With billions of photographs now available online, growing numbers of cameras capturing every moment, and people sharing the resulting images in an instant across the globe, what is the connection between even a single photograph and the basic truth of the reality it purports to represent? Focusing on geographic location, my research interest for my creative practice is in how photographs document and represent place. Place helps to define who we are. Place informs us about our past and about the foundations of our community and our culture. Photographs help to define place because they provide evidence for what is there, what was there, and what happened there. In my studio practice I explore the use of rephotography to highlight the differences in material form of place over time. The exhibition explores the place of the photograph in the modern world by comparing photographs taken in the past with those taken in the same places almost forty years later with a series of photographs taken in 1973 in and around Cronulla Street, south of Sydney, and rephotographs of the same scenes in 2011. They show sometimes subtle, sometimes clear, changes in our environment and behaviour that go unnoticed without photographic evidence. To better understand what the photographs in my exhibition are actually saying to us, and to explore what photographs from the past actually tell us, for my dissertation I examined a number of photographs from a more distant, nineteenth or early twentieth century past that proved to be ambiguous. On the basis of my research, I argue that the model of the nineteenth century photograph as an indexical truth, modulated by cultural interpretation, is more complex than is generally thought. Online access to substantially expanded resources through more sophisticated digital tools today shows clearly that the staged photographs should not be considered as 'false' simply because they are not documents of true events. They give us access to the way people then constructed their reality. This offers us useful information about the way they thought about themselves and their society. I also argue that online digital tools, the resources they allow us to access easily, and the opportunities provided by the internet to interact with each other change the rules significantly for Australian institutions of photographic history - galleries, libraries, archives and museums. These institutions are yet to realise the implications of these changed rules, and to embrace the opportunities provided by them to engage actively with individual researchers

Computational Re-Photography

Rephotographers aim to recapture an existing photograph from the same viewpoint. A historical photograph paired with a well-aligned modern rephotograph can serve as a remarkable visualization of the passage of time. However, the task of rephotography is tedious and often imprecise, because reproducing the viewpoint of the original photograph is challenging. The rephotographer must disambiguate between the six degrees of freedom of 3D translation and rotation, and the confounding similarity between the effects of camera zoom and dolly. We present a real-time estimation and visualization technique for rephotography that helps users reach a desired viewpoint during capture. The input to our technique is a reference image taken from the desired viewpoint. The user moves through the scene with a camera and follows our visualization to reach the desired viewpoint. We employ computer vision techniques to compute the relative viewpoint difference. We guide 3D movement using two 2D arrows. We demonstrate the success of our technique by rephotographing historical images and conducting user studies

The John Muir Newsletter, Spring/Summer 2012

Page 1 transcription missing PAGE 2 \u27Women as History-Makers In California Symposium The 59th California History Institute was held this past March at University of the Pacific. This year\u27s theme was Women as History-Makers in California. The event was planned and co- organized by Edith Sparks (Senior Associate Dean of the College), Jennifer Hel- gren, Assistant Professor of History, Corrie Martin, Director of the Women\u27s Resource Center, and W. Swa- gerty, Director of the John Muir Center. On Friday, March 23, twenty students and faculty motored to Sacramento to tour the California Museum. Exhibits on California\u27s Remarkable Women, Women and the Vote, and permanent exhibits including California\u27s Hall of Fame provided individual biographical introductions to around 120 women in the state\u27s history. A moment at the Constitutional Wall also reminded all of the importance of California\u27s beginnings and its continued promise to native born and immigrants alike. Historians, students, environmental activists, and community organizers came together in Grace Covell Hall on Saturday, March 24, to hear presentations. Edie Sparks and coauthor Jessica Weiss of California State, East Bay, opened the symposium with Placing Women in California History, emphasizing how women have remained in the background in most texts on the state\u27s history, despite their achievements as shapers of social, economic, political and legal themes unique to California. Alice Van Ommeren, a local Stockton historian, provided case studies of leaders among women during Stockton\u27s Golden Age, 1890-1940. Her case studies ranged from Lottie Gunsky, a career teacher (1853-1922), to Lilla Miller Lomax (1859-1941), Stockton\u27s first female medical doctor, to Laura DeForce Gordon (1838- 1907), suffragette and attorney who was the first woman in the U.S. to own a newspaper, to EdnaGleason (1914- 1961), the first woman to serve on the Stockton City Council and President of the California Pharmaceutical Association. Dawn Bohulano Mabalon of San Francisco State University connected her own family\u27s history with Stockton\u27s large Filipino community, noting that within the city, Little Manila once housed the largest community of Filipinos outside of Manila itself. After an Asian- theme luncheon, Professor Emerita of American Studies, Judy Yung (U.C. Santa Cruz) provided the key note on the theme of Chinese women in the state\u27s history giving examples from the era of the Gold Rush to the twentieth century of Chinese women who broke the stereotype of those who came to Gold Mountain. These include Au Toy, one of San Francisco\u27s most successful business women who owned houses of prostitution and gambling, Ana May Wong, the most famous Chinese- American actress in the state\u27s history; Jay Snow Wong, the celebrated Bay-area ce- ramicist; March Fong Eu, first Asian- American Secretary of State; and Betty Suan Chen, who received the Presidential Citizen Medal in 2010 for her social work among the homeless. Student papers by Pacific\u27s own Christiana Oatman and Devon Clayton focused on women and campus life and organizations. Clayton traced the history of women\u27s literary societies going back to the San Jose campus (1871-1924) and con nected these with modern sororities on the Stockton campus. Michelle Khoury from Santa Clara University informed all of the struggle of Native American women after the Gold Rush as they faced discrimination, stereotyping, and graphic ridicule for traditional lifestyles and attempts to survive in the hostile environment of Anglo-California. Women and Environmental Justice was the theme of the final panel, which included an overview by Professor Nancy C. Unger of Santa Clara University on women as Nature\u27s Housekeepers, and case studies by Tracy Perkins, U.C. Santa Cruz and Teresa DeAnda, Director of the Committee for Well Being of Earlimart on citizen action in policy and pesticide reform (respectively). Jennifer Helgren closed the symposium with remarks on what we have learned, tying the exhibits in Sacramento at the California Museum with the papers and presentations given on campus. Page 3 Archivist\u27s Corner Cruising in Muir\u27s Footsteps By Michael Wurtz Holt-Atherton Special Collections University of the Pacific Library Years ago as a history graduate student at Northern Arizona University in Flagstaff, I worked closely with the geography and geology departments. One of the geology grad students was involved with a project to re- photograph the Grand Canyon 100 years after Robert Brewster Stanton had surveyed and photographed a possible route for a railroad along the banks of the Colorado River in 1890 (Grand Canyon, A Century of Change: Rephotography of the 1889-1890 Stanton Expedition by Robert H. Webb 1996). The notes and markers that Stanton left made it possible to set up cameras in 1990 for precise re- photography. The grad student had told me that in one case they found Stanton\u27s footprints encased in petrified mud and knew exactly where he stood when he made the photo! This sense of place in history has been captivating to me ever since. In 2010, I traveled to Alaska for the first time, and I wanted to find John Muir\u27s footprints. Muir\u27s trips focused on Southeast Alaska, and I was going mostly into the interior. Fortunately, Muir and I did cross paths - albeit 111 years apart - in Prince William Sound and Cook Inlet. Muir was with the Harriman expedition in 1899, and I was on the Wurtz-Cosper trip of 2010. Dan Cosper\u27s father was stationed at Whittier in the 1950s, and there are many glacier cruises that embark from there. I gathered information on the cruise routes and compared them to Muir\u27s drawings and journals and notebooks. I harvested scans of the journals from the John Muir Papers website (go.pacific.edu/specialcollections), transcribed the text I could read, printed them out, and stuck them in Ziploc bags. Our initial trip to the Port Wells glaciers was to include a half-dozen more glaciers on the College Fjord, but our mighty boat the Klondike Express broke down, leaving us narrating stories and songs of that fateful cruise. The next day brought clearer skies and another glacier cruise to complete the mission. I could never triangulate most of the drawings as precisely as I was hoping, but the following were the best rephotography and they helped me to see Alaska as Muir saw it. — Muir\u27s notes indicate that he had drawn this opp[osite] Homer P.O. [Post Office] . The Post Office had moved many times, and the local museum could not clarify its location in 1899.1 went to an overlook behind town and snapped this photo from the about the same angle, but not the same aspect. (continued on page 8) Page 4 vihlcn ooaaAal cani^imJCe^, lo CtrWiiuurv =)Luvcotrva- t\u3eXoJt\inxu27u. in^AalaJoXe-, XJnuA aa/iincu -true Mkuj- Lew Vtvu. JLatumal Jo^tc tiAitiX&m, (continued from page 1) single photograph in my life. 2 Photographers such as, Carleton Watkins, George Fiske, Edward Curtis, Theodore Lukens, and C. H. Mer- riam stand out within the collection because of their thorough survey of western landscapes or their contribution to conserving or restoring them. Carleton Watkins is known as one of the great photographers of the West. In the summer of 1861, Watkins took his mammoth plate camera (18 x 22 glass plate negatives) to Yosemite to create highly detailed images of the Valley. According to the Getty Museum, he created a comprehensive photographic survey, which partly contributed to Abraham Lincoln\u27s signing of the 1864 bill that declared the valley inviolable, thus paving the way for the National Park system. 3 Watkins\u27 stereo cards of southern California landscapes depicting agricultural practices are also commonly found in the John Muir Papers. Carlton Watkins captured landscapes of the West. Muir may have used this photograph of an irrigated orange grove in San Gabriel as a guide to tending his own orchards. (f 15-764 John Muir Papers Holt-Atherton Special Collections©1984 Muir Hanna Trust) The extent of Muir and Watkins relationship is relatively indefinable, but in a letter from William Keith to Muir in 1909, Keith tells of Watkins\u27 son selling photographs from his father\u27s collection because Watkins was approaching blindness and financial hardship had left the family in need. Keith suggests, I gave him 50.00 and I think you ought to do something. 4 George Fiske is prominent in John Muir\u27s photo collection too, and was a principal photographer of the Yosemite Valley. He began in San Francisco and soon was working with Watkins and Eadweard Muybridge in Yosemite. In 1879 Fiske moved to the Yosemite Valley and was the first full-time resident photographer.5 Fiske was able to photograph the valley during every season. Muir responded to a threat to Fiske\u27s residency in the valley in 1905, I don\u27t believe there is the slightest danger of your being turned out of Yosemite Valley. If only one photographer should be left in the Valley, I think every right-minded person in the country would agree that you were that one. 6 George Fiske took A Glimpse of El Capitan in the summer and winter of 1880. His photographs of the Yosemite are very comprehensive and document the valley well. (f47 2722, f47-2723 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) The self-taught photographer Theodore Lukens used photography for his extensive research of trees. As a member of the Sierra Club, he was page 5 a friend of John Muir\u27s and an active conservationist and forester. In a letter written to John Muir from Lukens in 1897 about a stand of especially large oak trees near Santa Barbara, he states, Don\u27t you think I had better go up and measure the trees accurately, photograph them, and collect acorns and sprays of the foliage to send to you and Mr. Sargent. 7 Muir and Theodore Lukens corresponded about what was probably this large Oak that Lukens found near Santa Barbara. The photograph was taken by Lukens and probably sent to Muir along with some acorns and branches. (f 18-940 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) C. Hart Merriam, another amateur photographer, focused on zoology, ornithology, and later ethnography. Muir wrote letters to Merriam requesting photographs of varying subject matter for his books, Can you let me have a few telling photos of Sierra birds and beasts? bears, squirrels, chipmunks, neotoma, quail, grouse, woodpeckers etc. etc. etc. for illustrations? 8 Merriam\u27s lack of skill is evident throughout. His portrait of a porcupine is not compositionally balanced and shows someone\u27s boots and legs in the upper left corner. Bronzing, usually due to poor quality paper and improper developing method, can be found among Merriam\u27s images. C. Hart Merriam must have taken this photograph of a porcupine in Tuolumne Meadows in 1901 strictly for documentation as it is not aesthetically pleasing. (f45-2559 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) As the appointed photographer of the 1899 Harriman Expedition, Edward Curtis expansively documented the trip to Alaska. While on the expedition, Curtis began to gain an interest in the native peoples of the region and devoted the rest of his career to studying and documenting Native American tribes. Edward Curtis captured this image of Inuit children in Alaska on the Harriman Expedition of 1899. (f9 426 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) Looking through the John Muir Papers photography collection, one will observe many patterns. Landscapes, trees, animals, glaciers, botanical images, and family are among the frequent subjects that emerge in the collection, while less common subjects such as native peoples, land exploitation, and farming practices intermittently appear. Although Muir\u27s photographic collection included images from all over the world, California and Alaska are the dominant subjects in the collection. The images of California including Kings Canyon, Sequoia, and Pasadena, make up almost half of the entire eFL imoaed. L^ti|Wnl Page 6 (m\u3e, a, natwuui&t, a^aiaakeX, uatani&X, and. i&wLeA,, J\(maa, u&ed. pMataoAaaJluv la ejxamAnz. liAlina. ininaA aL true lacaXionA ne, -OxAileo. collection. As may be expected, roughly 575 images, the vast majority of California views, are of Yosem- ite\u27s vistas, trees, waterfalls, and more. A surprising amount of images of native peoples, their dwellings, and hieroglyphics from places like Yosemite, Alaska, Arizona, Utah, Africa, South East Asia, and Japan also surface in the collection. As a naturalist, geologist, botanist, and writer, Muir used photography to examine all living things at the locations he visited. He sent himself photographic postcards with flowers, landscapes, and native peoples to add to his collection. Muir also received photographs from his friends - especially images of trees. Many people sent him specimens and photographs of trees to identify or learn about new species. Lukens again sent Muir a letter in 1897, On my way home I met Mr. C. Knapp..., and he has promised to send me [a] branch and photo of an oak tree at his place 32 feet in cir. And he thinks it is the largest in this country. He went on to note, I will go up and photo it and get branches and acorns and send you some photos. 9 gg. POST CARD is- Muirwould purchase postcards to document botanical specimens that he found on his travels. (f20-1084 Pillsbury Picture Co. John Muir Papers Holt- Atherton Special Collections ©1984 Muir Hanna Trust) In another letter Muir expressed his gratitude for a photograph of a sugar pine sent by George King. Muir was very interested in the pine and wanted to know more about it. Where did you find that magnificent sugar pine? The finest specimen I have ever seen in a photograph. How tall is it, and how large in diameter 4 feet from the ground? 10 In addition to using photography for research, Muir used photographs in his conservation efforts. The collection consists of many photographs of logging, mining, railroads, and Hetch Hetchy. Muir expresses his joy of receiving some photographs from King again, I have received with many thanks your magnificent Hetch Hetchy photographs, a very telling lot. He went on to express, We are having a hard fight for Hetch Hetchy but think we will win. Help all you can. 11 Muir seems to have also collected photographs that document the exploitation of the land and the abuse of natural resources. This one is titled, Culling timber in Oregon and was planned to be used in a book. (f34-1933 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) Despite John Muir\u27s focus on nature, he collected nearly 800 images of his family and friends throughout his life. During the 19th and 20th centuries photography became a popular device for sharing one\u27s life. Nicole Hudgins claims that, the photo album of the 1890\u27s was a sort of Victorian Facebook, in the sense that dozens or even hundreds of portraits were preserved, displayed, and circulated among social and family networks. 12 In Muir\u27s correspondence it was not uncommon that a PAGE 7 portrait was either mailed to or from him. Although known for being alone in nature, many photographs reveal his good disposition and love of people. In one of the most touching of images of the collection, one can see the joy and love that Muir feels when surrounded by his grandchildren. A large number of images that are included in the Muir Papers illustrate the importance of people in his life. :.\u3c -- ■w-O V t **i\u3e*i W . ^M [uy_2 John Muir plays with his grandchildren Richard, John, and Strenzel Hanna in Martinez shortly before his death in 1914. (f24-1352 John Muir Papers Holt-Atherton Special Collections ©1984 Muir Hanna Trust) After analyzing the entire photography collection of John Muir, it seems that he used photographs for many diverse purposes. It is obvious that he used these images for research and to get a well rounded understanding of the areas in which he was interested. He also utilized the photographs to provide evidence to support his conservationist efforts, and he included images in association with his writing to provide readers with a view into his experiences. The collection also shows that he acquired photographs from numerous people including some of the most famous photographers of the West. In a letter to C. H. Merriam in December of 1900 Muir almost sums up his thoughts of photography in general when he says, Many thanks for the two fine lots of photographs. How well most of them have come out. The trees especially. They will be very useful to me besides bringing forward our fine trip last summer. 13 ENDNOTES 1. Ron and Maureen Willis, Photography as a Tool in Genealogy. Retyped by Ted Swift (Mountain View, CA). 2. Letter from John Muir to C. Hart Merriam 1901 Dec 31. John Muir Papers, Holt-Atherton Special Collections ©1984 Muir Hanna Trust. 3. Carleton Watkins. Getty Museum. http://www.getty.edu/art/gettyguide/ artMakerDetails?maker= 1989&page= 1 Accessed April 02, 2012. 4. Letter from William Keith to John Muir circa 1909. John Muir Papers, Holt- Atherton Special Collections ©1984 Muir Hanna Trust. 5. Views of Yosemite: George Fiske, 1880-1890. Bancroft Library. Online Archive California Library, http:// www.oac.cdlib.org/findaid/ark:/13030/ tf238nb395/. 6. Letter from John Muir to George Fiske, 1905 Mar 13. John Muir Papers, Holt- Atherton Special Collections ©1984 Muir Hanna Trust. 7. Letter from Theodore Lukens to John Muir, 1897 Jun 29. John Muir Papers, Holt-Atherton Special Collections ©1984 Muir Hanna Trust. 8. Letter from John Muir to C. Hart Merriam 1901 Mar 28. John Muir Papers, Holt-Atherton Special Collections ©1984 Muir Hanna Trust. 9. Letter from Theodore P. Lukens to John Muir 1897 Jun 30. John Muir Papers, Holt-Atherton Special Collections ©1984 Muir Hanna Trust. 10. Letter from John Muir to George King Nov 1913. John Muir Papers, Holt- Atherton Special Collections ©1984 Muir Hanna Trust. 11. Letter from John Muir to George King Nov 1913. John Muir Papers, Holt- Atherton Special Collections ©1984 Muir Hanna Trust. 12. Nicole Hudgins, A Historical Approach to Family Photography: Class and Individuality in Manchester and Lille, 1850 - 1914, (Journal of Social History, 2010), 565. 13. Letter from John Muir to C. Hart Merriam 1900 Dec 26. John Muir Papers, Holt-Atherton Special Collections ©1984 Muir Hanna Trust. Page 8 (continued from page 3) Surprise Glacier was an easy one to spot with its distinctive medial moraine. Our tourist boat did not get as close in as Muir, so I was unable to get the exact angle or aspect. The drawings do not capture the detail that a photograph can, but the Catarack Gl[acier] on the left seems to have receded quite a bit. This was on the Harriman Fjord of Port Wells of Prince William Sound. The focus of this drawing and photograph is actually a tributary of the Serpentine Glacier. The Serpentine Glacier itself is the debris-covered glacier that we can only see entering the Fjord in the foreground from the right. It appears that the tributary has receded quite a bit. All drawing pages are from June-July 1899, Harriman Expedition to Alaska, Part II, Reel 29 Journal 3, John Muir Papers, Holt- Atherton Special Collections, University of the Pacific Library. © 1984 Muir-Hanna Trust. Cascade Glacier was one the steepest we saw on our cruise. We did not get close enough to see it quite like Muir on the Harriman expedition in 1899. On many occasions, Muir had the opportunity to get off the boat and hike around. Barry Glacier is on the right. Book Review Page 9 The Making of Yosemite: James Mason Hutchings and the Origin of America\u27s Most Popular National Park. By Jen A. Huntley. (Lawrence: University Press of Kansas, 2011. xi +232 pp. Illustrations, maps, notes, bibliography, index. 34.95.) Occasionally a book alters our general understanding of an individual and that person\u27s place in history. This study is one of those, shedding new light on James Mason Hutchings (1820-1902). Born in Towcester, Northamptonshire, England, Hutchings grew up in the geographic center of England, the sixth child of William, a carpenter, and Barbara, a paper lace maker. Lured to America by George Catlin\u27s touring exhibit of American Indian portraits, Hutchings immigrated to California in 1848 and located himself in Placerville during the height of the Gold Rush. In 1855, after seven years of part-time mining, part-time real estate speculation, and occasional newspaper editing, Hutchings visited Yosemite, a tipping point in his life. Seeing opportunity in promoting California, Hutchings moved to the valley, established himself as an entrepreneur in Yosemite, providing services for tourists and building a hotel, sawmill, and other facilities, some of the earliest infrastructure within the future national park. From 1855 to his death in 1902, Hutchings\u27 life and the Anglo expropriation and promotion of Yosemite were inextricably linked. This is the second recent biography of Hutchings, and goes well beyond Dennis Kruska\u27s James Mason Hutchings of Yo Semite: A Biography and Bibliography (San Francisco: Book Club of California, 2009), which emphasizes his contributions in print, notably letter sheets, almanacs, and Hutchings\u27 California Magazine (1856-1861). Through careful and thorough research, Hundley introduces a man we have not known, a misunderstood businessman, husband, father, and patron of the arts and sciences, who has received mixed treatment by previous scholars more interested in t

Crossroads on the Coast: A Preliminary Examination of Bridgetown, Antigua

In 1675, the English government passed a law that established six “trade towns” on Antigua. The law required that all imports, exports, and intra-island trade be conducted in these towns to be assessed for taxes. Of the six original towns – St. John’s, Parham, Falmouth, Carlisle Road, Bridgetown, and Bermudian Valley – all but two survive today: St. John’s, Parham, and Falmouth exist as they were, and Carlisle Road is now called “Old Road.” The remaining two towns were abandoned sometime in the past: Bermudian Valley’s location has been lost, and Bridgetown was abandoned in the 19th century, its inhabitants moving up the hill and establishing the modern town of St. Philip’s – the name of the church at Bridgetown. In 2016 I conducted preliminary archaeological surveys at the Bridgetown site and elsewhere on the island, in cooperation with Antigua National Parks Authority, to begin documenting the deterioration of the town ruins, compared to previous assessments done between 1987 and 1996, assess offshore cultural resources in the associated harbour, and to begin to answer questions about the town’s abandonment and assess the veracity of various local legends surrounding the site. This project serves as a pilot study towards a Ph.D. dissertation research project, which will aim at exploring the influence of Antigua’s sugar economy within the world trade network in the Early Modern Period

Painting-to-3D Model Alignment Via Discriminative Visual Elements

International audienceThis paper describes a technique that can reliably align arbitrary 2D depictions of an architectural site, including drawings, paintings and historical photographs, with a 3D model of the site. This is a tremendously difficult task as the appearance and scene structure in the 2D depictions can be very different from the appearance and geometry of the 3D model, e.g., due to the specific rendering style, drawing error, age, lighting or change of seasons. In addition, we face a hard search problem: the number of possible alignments of the painting to a large 3D model, such as a partial reconstruction of a city, is huge. To address these issues, we develop a new compact representation of complex 3D scenes. The 3D model of the scene is represented by a small set of discriminative visual elements that are automatically learnt from rendered views. Similar to object detection, the set of visual elements, as well as the weights of individual features for each element, are learnt in a discriminative fashion. We show that the learnt visual elements are reliably matched in 2D depictions of the scene despite large variations in rendering style (e.g. watercolor, sketch, historical photograph) and structural changes (e.g. missing scene parts, large occluders) of the scene. We demonstrate an application of the proposed approach to automatic re-photography to find an approximate viewpoint of historical paintings and photographs with respect to a 3D model of the site. The proposed alignment procedure is validated via a human user study on a new database of paintings and sketches spanning several sites. The results demonstrate that our algorithm produces significantly better alignments than several baseline methods