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1.
This work faces the problem of detecting decay zones from color images of stone materials. In Cultural Heritage, the extraction of degradation regions from images of ancient monuments represents an important step forward in studying and analyzing the state of preservation of historical buildings. Generally the decay diagnosis is provided by “naked eye” analysis done by expert scientists “walking around” the artifact and recording the conservation state of each individual element they observe. In addition to this kind of investigation, the application of an image segmentation strategy to color images of stony materials can be used in order to extract regions characterized by a visible chromatic alteration, changes in color, for example, as oxidation or concretion. This paper features a color image segmentation approach founded on the fast marching numerical method. We have applied this technique for its possibility to work locally, that is, only the contour of the region under study is processed. In addition to this method, we present a global approach, that is, the possibility to extract decay regions from the entire image; these regions are spatially disconnected but with similar colorimeter value. The main aim of the present work is to provide a tool that helps the expert to contour the degraded regions. In this sense even if the results of the proposed procedure depend on the expert evaluation, the approach can be a contribution to improve the efficiency of the boundary detection process. The study case concerns the impressive remains of the Roman Theatre in the city of Aosta (Italy). In the image segmentation process the color space L*a*b* is utilized.  相似文献   

2.
To create photorealistic three-dimensional (3D) models of real scenes and objects is a challenging problem that demands advanced knowledge of computer vision and computer graphics. Systems that can reconstruct the 3D model of cultural artefacts have found many applications such as virtual museum and historical archiving. While there are methods for 3D digitization of cultural artefacts with high geometric resolution, there are still limitations in achieving high textural resolution for virtual exhibition. One major problem is that the object surface exhibits specular reflection of illuminated light during the acquisition of surface texture. The shading of the target object does not match to other objects or pictures in the virtual scene. Also, if texture of the object must be composed of multiple images, the mismatch of shading (radiometric difference) among the images can be very prominent. In order to create high visual quality exhibition, the specular reflections must be eliminated and then the virtual scene is relit by a synthetic light source. Most existing methods for the identification and removal of specular reflection component demand special device or rely on information obtained in a single image. In order to reconstruct a complete 3D model, we need to acquire a multi-view image sequence. We therefore propose a new method that is applicable for the separation of diffuse and specular reflection components in multi-view image sequence. Also, our method can tackle the specular reflection across the texture boundary. The image sequence is first normalized by the estimated illumination color. Based on the dichromatic reflection model, the specular chromaticity is replaced by the corresponding diffuse chromaticity, which can always be found in neighboring views with the highlights already faded away. We test the new method in modeling Yixing ceramic teapots. The shape model of the teapot is obtained by a laser scanner. The diffuse image sequence is then used to generate the texture map. We create the virtual scene with the photorealistic 3D teapot model, some synthetic 3D models and still pictures. Interactive exhibition of the artefact is achieved with the control of the mouse and simple keyboard commands. This paper gives an account of the procedures for the creation of interactive virtual exhibition of ceramic artefacts.  相似文献   

3.
In the field of Cultural Heritage, image analysis represents an indispensable practice for restorers to collect information about the state of preservation of monuments and artifacts and plan restoration interventions. In addition, during the last two decades, the wide spread of remote sensing technologies and the possibility to build 3D reality-based models of artifacts allow the extension of image analysis to 3D environments. In this context, the purpose of this contribution is to show the results of investigations held in order to provide a methodology for the automatic detection of deteriorated areas within architectures and artifacts using colour images as a field of examination. Using both 2D and 3D segmentation approaches, our methodology aims at speeding and efficiently performing the automatic detection of deteriorated zones within Cultural Heritage and therefore segment 3D digital models acquired using different survey technologies. Within our investigations, we selected case studies concerning recurrent deteriorations, such as, for example, detachments, cracks and chromatic alterations; we run them both to manual and to automatic recognition and selection tests, in order to compare the results obtained using these approaches and evaluate the reliability of the automatic one. Results comparison included computational and user time, quantification of the deteriorated area error between manual and automatically detected zones. Additional parameters characterizing the specific type of deteriorations were also computed for each case study. Comparison between the automatic and the manual procedure showed that the automatic detection is faster and reliable in all our selected case studies, with evident improvements in the efficient evaluation of the entity and extension of deteriorated areas on 3D geometry.  相似文献   

4.
Driven by the pressure to permanently release a large number of books, publishers have to allocate limited advertising budgets across the wide range of newly released books. As in many creative industries, publishers often focus their advertising activities on potential top sellers written by recent bestselling authors. Considering potential selection effects in choosing the “right” books for advertising, this paper investigates (1) whether selection effects exist and to what extent potential selection effects influence the relation between book advertising and book sales and (2) the boundary conditions under which book advertising leads to higher sales by focusing on the “star power” effects of authors. By applying propensity score matching to a dataset of 598 fiction books from the German book market, we identify substantial selection effects that lead to a serious overestimation of advertising effectiveness by up to 41 % (10,000 copies sold). Using group analyses, we find that sales of books written by recent bestselling authors are not significantly influenced by advertising activities of publishers; however, the sales of books written by lesser-known authors can be increased significantly if they are advertised. Our findings are highly relevant for publishers, indicating that a shift in the allocation of advertising budgets toward promising books by lesser-known authors is recommended to improve the overall advertising effectiveness.  相似文献   

5.
In this article we present our global approach to the problem of accurate 3D measurement and reconstruction of 3D works of art using a calibrated multi-camera system. In particular, we illustrate a simple and effective adaptive technique for the self-calibration of CCD-based multi-camera acquisition systems with minimum a-prior information. We also propose a general and robust approach to the problem of close-range partial 3D reconstruction of objects from stereo-correspondences. Finally, we introduce a method for performing an accurate patchworking of the partial reconstructions, based on 3D curve matching.  相似文献   

6.
Virtual restoration of cultural heritage (CH) artefacts is an important task that aims to digitally recreate the original appearance of damaged items. In this paper, a method that can be used for virtual restoration of faces appearing in damaged Byzantine icons is presented. Given a damaged face, the complete three-dimensional (3D) geometry of the face is reconstructed using data from the non-damaged facial parts and the texture of the damaged areas is restored. A key aspect of the proposed method is the use of a customized 3D deformable face model suitable for representing the geometry of Byzantine faces, the so-called Byzantine Style Specific Model (BSSM). A BSSM is generated by enforcing rule-based constraints on a deformable model trained using 3D scans of human faces. The use of a BSSM ensures that the Byzantine style is preserved during the process of shape restoration.  相似文献   

7.
Terrestrial laser scanning technique has represented one of the more advances occurred in the last years in the field of data acquisition. Time-of-Flight (TOF) systems provide a fast and reliable tool to measure millions of 3D points allowing a very effective and dense measurement of the surface geometry. Nowadays, the generation of high quality 3D models is a practice applied to different kind of objects: small or medium size artworks, parts of human body, cars, buildings, civil infrastructures (like dams, bridges, plants, etc.) and whole archaeological sites as well. In most cases, in order to capture the whole object geometry a number of single scans need to be acquired from different positions and then stitched together (i.e. registered each other) to generate the full 3D model. The automatization of the registration of multiple scans acquired from a terrestrial laser scanner (TLS) still represents a very attractive research field. The chance to automatically align several point clouds would reduce processing costs in terms of time and human resources. In addition it would allow even non-specialist users to produce 3D models with good quality. This paper contributes to this research area by presenting a method for the automatic registration of very dense point clouds acquired by TLS systems. The proposed solution is an extension to large datasets of an automatic range data registration procedure we developed a few years ago for the modelling of point clouds acquired with close-range laser scanners. Such procedure, based on the spin-images (SIs) algorithm, has been then improved with the introduction of a multi-resolution method that generates a pyramid of spin-images in order to speed up the matching between adjacent scans. The results we present show that this method can be successfully applied for the automatic registration of high density laser scans of complex and large structures of Cultural Heritage.  相似文献   

8.
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9.
Several new tools to obtain three-dimensional information from unorganized image sets are now available for the public use. The main advantage of this software, which is based on dense stereo matching, is the possibility to generate 3D content without the need of high-cost hardware (e.g. 3D scanning devices). Nevertheless, their use in real-world application domains (like cultural heritage) is still not very diffused, due to the non-straightforward usability of the raw data produced. In this paper, we investigate the use of automatic dense stereo reconstruction tools for the monitoring of an excavation site. A methodology for the effective acquisition and processing of data is presented. In addition, the results of the data assessment demonstrate the repeatability of the data acquisition process, which is a key factor when qualitative analysis is performed. The use of three-dimensional data is integrated in an open source mesh processing tool, thus showing that a spatio-temporal analysis can be performed in a very intuitive way using off-the-shelf or free/open digital tools. Moreover, the use of peculiar rendering and the creation of snapshots from arbitrary points of view increase the amount of documentation data, and suggest a perfect integration of data produced with dense stereo matching in the future standard documentation for excavation monitoring.  相似文献   

10.
This paper describes how some innovative methodologies have been designed and employed to support the restoration of the Madonna of Pietranico, a terracotta statue severely damaged in the 2009 earthquake. The statue, fragmented in many pieces, has undergone a complex restoration performed by a multidisciplinary working group. The contribution of digital technologies was planned from the very beginning, since the complexity of this restoration originated the design of innovative procedures for managing the reassembly and restoration process. The Madonna test bed was therefore an example of how technology innovation could be pushed by clear application needs. A first important contribution was the study of the recombination hypothesis of the fragments. This initial phase was performed on digitized 3D models of the statue fragments, with the aim of reducing fragments manipulation, preventing further damages and increasing the capabilities to rehearse and evaluate different reassembly options. The accuracy of the 3D scanned models and the new recombination procedure introduced in this paper allowed to manage this phase in the digital domain with successful results. The digital 3D models were also used to design and produce an innovative supporting structure, constructed with a rapid prototyping device. Another important contribution concerned the study and virtual restoration of the polychrome decoration of the statue; our aim was to reproduce and restore in the virtual 3D domain the very complex original polychrome decoration, on the base of the remaining traces. Consequently, new virtual painting functionalities have been designed on the MeshLab platform (an open-source tool for 3D models visualization and manipulation) for reproducing pictorial decorations over digital 3D models and have been assessed on this specific test bed. This allowed us also to investigate the complexity of the virtual repainting process and to identify further technology enhancements. Finally, computer graphics technologies have been also used to produce a video that tells the story of the restoration.  相似文献   

11.
We offer four theses about how intercultural communication is altered in a digitally networked era. Digital media shape intercultural communication by (1) producing new public fora capable of (2) hosting rich, multimodal “spaces” of contact on (3) a scale of many-to-many communication that (4) challenges traditional modes of representation.  相似文献   

12.
In the present paper, we analyse the allocation process for cultural services in Norwegian municipalities. The cultural sector at this administrative level is decomposed into the following eight subcategories: children’s and youth activities, libraries, cinemas, museums, arts dissemination, cultural heritage, cultural schools, and other cultural services. By means of budget shares for these eight cultural services and a residual sector consisting of all other municipal services, we estimate a system of demand relations which are interdependently linked to each other by a budget restriction. Our analyses are based on data from 409 out of 429 Norwegian municipalities during the period 2002–2010. In the empirical analyses, we mainly focus on the effects of income variation for the cultural services. We estimate effects of free income, matching grants to each sector, and user fees and other sector-specific income for each sector. We also estimate crowding-out effects for the cultural sectors of demographic variables indicating higher demand for services such as education, childcare, and health services. Our results confirm previous results. There are interesting differences within the group of cultural services, and these are partly related to different levels of national standardisation and regulation among the cultural services.  相似文献   

13.
This paper examines Duchenne de Boulogne's Mécanisme de la physionomie humaine (1862) as a limit case between Foucauldian epistemes of signification. Electrically inducing ‘expression’ in his subject's face, Duchenne, a neuro-physiologist, claimed to have discovered the true ‘orthography’ of the passions. He photographed and published his experiments to offer the art world a positivist corrective to the historically ‘arbitrary’ representation of emotion. The narrative accompanying the photographs provides the basis for this analysis which focuses on how Duchenne used the image/text idea of an ’orthography‘ to shape his technologically mediated expressions with a Renaissance and Classical poetics of resemblance and representation. Making an analogy with linguistic ‘units’, Duchenne located a scene of writing under the facial flesh where action was ‘transfigured’ into passion. The Classical debate on the origin of language and the Renaissance physiognomic tradition inspired his discourse, which failed to grasp the modernity of his technologically mediated passions.  相似文献   

14.
This paper deals with a possible application of computer vision techniques in the field of Cultural Heritage. These techniques allow an effective integration of data from different sources. Particular consideration will be given to an accurate geometric analysis of the zone under study in order to detect degradation damage in historical building-stone materials. To this end, we employ a computer vision technique, known as the Shape from Shading method, for which a photographic image of the stone material under consideration is the only input data required. By using this method, it is possible to recover, under some constraints, the shape of the three-dimensional surface of the object from the photographic image. In order to improve the results, in this paper, we implement this technique by using an optimization approach which allows a suitable integration of photographic and spatial data, the latter of which is obtained by a topographical device. We outline the potentialities of the method which mainly consist of two relevant capabilities. The first one is the geometric shape reconstruction of the surface material at a resolution much higher than the one allowed by topographical acquisition. The second one is the correction of the lighting-induced distortions in the photographic image. Such a correction is relevant for further image-based analysis of the degradation of the stone material. Experimental results, obtained by using both photographic and spatial data relative to a pudding stone with degradation, are presented and discussed.  相似文献   

15.
A number of software solutions based on the Structure-From-Motion (SFM) and Dense Multi-View 3D Reconstruction (DMVR) algorithms have been made recently available. They allow the production of high quality 3D models by using unordered image collections that depict a scene or an object from different viewpoints. In this work, we question the quality of the data produced by a commercial SFM-DMVR software. An Ottoman monument located in the region of Xanthi, Greece has been selected as a case study. We attempted to quantify the quality of the SFM-DMVR data in relation to the data produced by a Time-of-Flight terrestrial 3D range scanner. We have implemented a number of comparisons between different parts of the monument in order to assess the mesh deviations and the reconstruction's accuracy. In order to further ensure the validity of our evaluation phase, we performed additional distance measurements between feature points on the monument's surface by using a total station and empirical measurements. The applicability of the SFM-DMVR method was questioned by creating a complete 3D digital replica of the monument.  相似文献   

16.
The evolution of real time 3D graphics technologies in combination with high bandwidth Internet connections and modern Web browsers enable users to explore complex 3D scenes. As a rule, a virtual visitor has to manually explore the geometrically complex 3D model in order to discover points of interest. This manual exploration is a time consuming process that, in some cases, can be assisted by sets of predefined points of interest. In this paper, we propose the annotation of 3D scenes in order to equip the user with a text based 3D scene search engine. The search engine provides a query mechanism that unburdens the user from the time consuming process of manually exploring vast 3D scenes. It responds to queries by exploiting the metadata of each 3D model and returns textual and visual information along with a group of links that correspond to relative points of interest within the 3D scene. The search engine allows the virtual visitor to automatically be transferred to a specific point of interest. We have built a Web accessible prototype system that is able to handle queries related to historical data, topological relationships and architectural properties of buildings. A number of 3D reconstructions covering urban areas of cultural importance located in Northern Greece have been annotated and used in the search engine as case studies. The prototype system is based on open source technologies and on a hybrid metadata schema that is derived from the MIDAS Heritage and MACE schemas.  相似文献   

17.
The need of inspecting a masterpiece of fine art without affecting it led to develop non destructive methods of investigation. In the field of art conservation, several diagnostic techniques are being widely used to inspect works of art, giving different but complementary results. The present work deals with two of these methods, reflectography and thermography, both techniques examining objects in the infrared spectrum but in different wavelength bands. Their integrated data potentially provide a powerful tool for mapping hidden features and alterations of artworks. This was confirmed during the inspections of a 13th century panel painting under restoration at the Opificio delle Pietre Dure laboratories (Florence, Italy). A graphical user interface was also designed to aid operators in the field of conservation dealing with the results of the two IR methods. Many options such as image adjustment, comparison, overlaying and transparency variation, in addition to thermographic elaborations, have been made available to users. Imaging data integration provides a multi-layered and multi-spectral representation of the painting that yields a comprehensive diagnosis confirms the anomalies individuation and reduces the ambiguities of information coming from a single diagnostic method.  相似文献   

18.
ABSTRACT

Analyses of the relationship between economy and sentiment tend to focus on connection rather than separation. Scholars recognize that individuals sometimes identify moral conflicts between economy and sentiment, but primarily focus their research on the boundary or relational work performed to mitigate or disappear the conflict. Instead, I analyze how individuals talk about the relationship between economy and sentiment as separate or hostile, comparing two theoretically distinct groups: non-religious individuals and practicing evangelicals. The comparison allows me to analyze patterns of discourse and boundary-making based on access to institutionalized culture. I find that both groups articulate perceptions of hostile worlds by: (1) maintaining the taboo against talking about money, (2) recommending neutral separation, and (3) demarcating areas of life as too sacred for money. Through comparison, I find that non-religious respondents describe a less permeable vertical boundary line, whereby economy and sentiment are separated into separate spheres, as if side-by-side, while evangelicals describe a more permeable horizontal boundary line, where separation is maintained through the use of consistent hierarchical discourses that assert the moral importance of sentiment over economy. My findings underscore how unequal access to cultural schema differentially shape how individuals connect economy and sentiment, if at all.  相似文献   

19.
Although languages and cultural boundaries circumscribe the reach of news, global news regularly flows across geographical boundaries at high velocity, particularly on social media. This research explores the role multicultural individuals play in global news flows on the Twitter social media platform. We examine the case of a Chinese documentary film about pollution. Through a quantitative network analysis, we identify the key opinion leaders in the Chinese and English language discussion of the film on Twitter. An in-depth qualitative analysis was then conducted on the opinion leaders to understand their different strategies and practices for constructing and disseminating global news.  相似文献   

20.
This paper investigates how video game publishers’ choice of game release date is affected by the expected level of competition within the game’s product niche. We identify game niches by genre, age-appropriateness, console system, a release cohort, and publisher. First, we show that games are more likely to be released so as to avoid weeks when their niche already faces competition. Next, we show that consumer substitution across games is stronger within most of the dimensions describing product niches. Sales volumes decay quickly after the opening weekend, so at any point in time, a niche will typically be served by few current titles. From this, we calculate that delaying game release 1 week yields substantial increase in revenue for a video game facing higher-than-average competition.  相似文献   

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