1,721,150 research outputs found
A Modified Look-up Table for Implicit Disambiguation of Marching Cubes
No full textA new triangulation scheme for the Marching Cubes algorithm is proposed. The scheme allows the extraction of continuous isosurfaces from volumetric data without the need to use disambiguation techniques
Fast and simple automatic alignment of large sets of range maps
No full textWe present a very fast and simple-to-implement algorithm for the automatic registration of a large number of range maps. The proposed algorithm exploits a compact and GPU-friendly descriptor specifically designed for the alignment of this type of data. This pairwise registration algorithm, which also includes a simple mechanism to avoid to get false positives, is part of a system capable to align a sequence of up to hundreds of range maps in few minutes. In order to reduce the number of pairs to align in the case of unordered range maps we use a prioritization strategy based on the fast computation of the correlation between range maps through FFT. The proposed system does not need any user input and it was tested successfully on a large variety of datasets coming from real acquisition campaigns
CAA 2015 Keep the Revolution Going. Proceedings of the 43rd Conference on Computer Application in Archaeology
Full text linkThis volume brings together all the successful peer-reviewed papers that have been submitted for the proceedings of the 43rd conference on Computer Applications and Quantitative Methods in Archaeology that took place in Siena (Italy) from March 31st to April 2nd 2015.
The number of people who signed on for CAA 2015 really took us by surprise: 550 delegates registered for the conference, from many more places than we would ever have anticipated. Altogether, within the four days of the conference 280 papers were presented in 48 sections divided into ten macro topics, 113 posters, 7 roundtables and 12 workshops.
That number, in itself, has prompted a thought or two. Above all it says to us that CAA is very much alive and kicking, that it is in robust good health, and that it remains a wholly relevant force in the scientific community, fully engaged with the questions of the day, and a continuing focal point for the profession. All of that speaks well for the motto of CAA 2015: KEEP THE REVOLUTION GOING!
archaeology are deeply embedded within our universities. This is all good, of course, but we must not assume that the task has been completed. An intrinsic revolutionary instinct towards technological development has been awakened. But it will only survive by virtue of the results that it brings about. Or using the words of our Chairman Prof Gary Lock: ‘Computers not only change the way we do things, but more importantly they change the way we think about what we do and why we do it’. The general thrust of this statement can be summed up and reinforced by recalling a quote from the philosopher Don Ihde, who has argued we should never forget that all technologies should be regarded as ‘cultural instruments’, which as well as strategies and methodologies implemented in our researches are also ‘non-neutral’.
So KEEP THE REVOLUTION GOING! is a motto that lays stress on the need to maintain innovation in archaeology through technological advances. But innovation must have at its root the fostering of critical thought and the framing of new archaeological questions. So there is much work still to be done, and fresh challenges to be faced in the months, years and decades ahead.
One final thought. The date of this conference, and most of all the opening ceremony, has not come about by chance. The 30th of March, for the University of Siena and in particular for the human sciences and archaeology, represents a sad but enduring anniversary. Eight years ago on this day we lost a key figure in the Italian archaeological community of the last 50 years; a man who had an extraordinary influence on many aspects of medieval and archaeological studies. Not least we call to mind his role in the promotion and development of digital archaeology. Our thoughts and memories go therefore to our friend and mentor Professor Riccardo Francovich. He always inspired us to seek new horizons and without him we doubt that this conference would have found its way to Siena.
Although the significance of our motto is obvious, we think it is worth some thoughts. Few would deny that in the past 30 years or so, digital technologies have profoundly revolutionised archaeology – in the office and laboratory, in the field and in the classroom. The progressive introduction of digital techniques in the archaeological process has of course led to a general increase in efficiency. But perhaps more importantly it has provided a spur to the discussion of methodology and through that has strongly influenced not only the way we go about things but also the outcomes that we have been able to achieve.
The pioneering phase in the application of digital techniques in archaeological research has clearly been fruitful and today computer applications such as GIS, databases, remote sensing and spatial analysis as well as virtual and cyber task has been completed. An intrinsic revolutionary instinct towards technological development has been awakened. But it will only survive by virtue of the results that it brings about. Or using the words of our Chairman Prof Gary Lock: ‘Computers not only change the way we do things, but more importantly they change the way we think about what we do and why we do it’. The general thrust of this statement can be summed up and reinforced by recalling a quote from the philosopher Don Ihde, who has argued we should never forget that all technologies should be regarded as ‘cultural instruments’, which as well as strategies and methodologies implemented in our researches are also ‘non-neutral’.
So KEEP THE REVOLUTION GOING! is a motto that lays stress on the need to maintain innovation in archaeology through technological advances. But innovation must have at its root the fostering of critical thought and the framing of new archaeological questions. So there is much work still to be done, and fresh challenges to be faced in the months, years and decades ahead.
One final thought. The date of this conference, and most of all the opening ceremony, has not come about by chance. The 30th of March, for the University of Siena and in particular for the human sciences and archaeology, represents a sad but enduring anniversary. Eight years ago on this day we lost a key figure in the Italian archaeological community of the last 50 years; a man who had an extraordinary influence on many aspects of medieval and archaeological studies. Not least we call to mind his role in the promotion and development of digital archaeology. Our thoughts and memories go therefore to our friend and mentor Professor Riccardo Francovich. He always inspired us to seek new horizons and without him we doubt that this conference would have found its way to Siena
A Low-Memory, Straightforward and Fast Bilateral Filter Through Subsampling in Spatial Domain
No full textGAIL: Geometry-aware Automatic Image Localization
No full textThe access and integration of the massive amount of information, that can be provided by the web, can be of great help in a number of fields, including tourism and advertising of artistic sites. A "virtual visit" of a place can be a valuable experience before, during and after the experience on-site. For this reason, the contribution from the public could be merged to provide a realistic and immersive visit of known places. We propose an automatic image localization system, which is able to recognize the site that has been framed, and calibrate it on a pre-existing 3D representation. The system is characterized by very high accuracy and it is able to validate, in a completely unsupervised manner, the result of the localization. Given an unlocalized image, the system selects a relevant set of pre-localized images, performs a Structure from Motion partial reconstruction of this set and then obtain an accurate camera calibration of the image with respect to the model by minimizing distances between projections on the model surface of corresponding image features. The accuracy reached is enough to seamlessly view the input image correctly super-imposed in the 3D scene
Controlled and adaptive mesh zippering
No full textMerging meshes is a recurrent need in geometry modeling and it is a critical step in the 3D acquisition pipeline, where it is used for building a single mesh from several range scans. A pioneering simple and effective solution to merging is represented by the Zippering algorithm (Turk and Levoy, 1994), which consists of simply stitching the meshes together along their borders. In this paper we propose a new extended version of the zippering algorithm that enables the user to control the resulting mesh by introducing quality criteria in the selection of redundant data, and allows to zip together meshes with different granularity by an ad hoc refinement algorithm
3D reconstruction for featureless scenes with curvature hints
No full textWe present a novel interactive framework for improving 3D reconstruction starting from incomplete or noisy results obtained through image-based reconstruction algorithms. The core idea is to enable the user to provide localized hints on the curvature of the surface, which are turned into constraints during an energy minimization reconstruction. To make this task simple, we propose two algorithms. The first is a multi-view segmentation algorithm that allows the user to propagate the foreground selection of one or more images both to all the images of the input set and to the 3D points, to accurately select the part of the scene to be reconstructed. The second is a fast GPU-based algorithm for the reconstruction of smooth surfaces from multiple views, which incorporates the hints provided by the user. We show that our framework can turn a poor-quality reconstruction produced with state of the art image-based reconstruction methods into a high- quality one
Painting with Bob:Assisted creativity for novices
Full text linkCurrent digital painting tools are primarily targeted at professionals and are often overwhelmingly complex for use by novices. At the same time, simpler tools may not invoke the user creatively, or are limited to plain styles that lack visual sophistication. There are many people who are not art professionals, yet would like to partake in digital creative expression. Challenges and rewards for novices differ greatly from those for professionals. In this paper, we leverage existing works in Creativity and Creativity Support Tools (CST) to formulate design goals specifically for digital art creation tools for novices. We implemented these goals within a digital painting system, called Painting with Bob. We evaluate the efficacy of the design and our prototype with a user study, and we find that users are highly satisfied with the user experience, as well as the paintings created with our system.</p
Decreasing Iso-Surface Complexity via Discrete Fitting
No full textSince the introduction of techniques for isosurface extraction from volumetric datasets, one of the hardest problems has been to reduce the number of generated triangles (or polygons). This paper presents an algorithm that considerably reduces the number of triangles generated by a Marching Cubes algorithm, while presenting very close or shorter running times. The algorithm first assumes discretization of the dataset space and replaces cell edge interpolation by midpoint selection. Under these assumptions the extracted surfaces are composed of polygons lying within a finite number of incidences, thus allowing simple merging of the output facets into large coplanar triangular facets. Lastly, the vertices which survived the decimation process are located on their exact positions and normals are computed
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