1,721,025 research outputs found
Tre documenti inediti su Spirito Benedetto Nicolis di Robilant: la produzione del blu di cobalto e la separazione dell'argento dal rame per liquazione nel ‘700
No full textSpectral-based segmentation for functional shape-matching
No full textIn Computer Graphics and Computer Vision, shape co-segmentation and shape-matching are fundamental tasks with diverse ap-
plications, from statistical shape analysis to human-robot interaction. These problems respectively target establishing segment-
to-segment and point-to-point correspondences between shapes, which are crucial task for numerous practical scenarios. No-
tably, co-segmentation can aid in point-wise correspondence estimation in shape-matching pipelines like the functional maps
framework. Our paper introduces an innovative shape segmentation pipeline which provides coherent segmentation for shapes
within the same class. Through comprehensive evaluation on a diverse test set comprising shapes from various datasets and
classes, we demonstrate the coherence of our segmentation approach. Moreover, our method significantly improves accuracy
in shape matching scenarios, as evidenced by comparisons with the original functional maps approach. Importantly, these en-
hancements come with minimal computational overhead. Our work not only introduces a novel coherent segmentation method
and a valuable tool for improving correspondence accuracy within functional maps, but also contributes to the theoretical
foundations of this impactful field, inspiring further research
Vector graphics on surfaces using straightedge and compass constructions
No full textWe port classical straightedge and compass constructions to manifold surfaces under the geodesic metric. We propose two complementary approaches: one working on the tangent plane; and another working directly on the surface. In both cases, many constructions lack some of the geometric properties they have in the Euclidean case. We devise alternative constructions that guarantee at least a subset of such properties. We integrate our constructions in the context of a prototype system supporting the interactive drawing of primitives of vector graphics
Non-uniform interpolatory subdivision schemes with improved smoothness
No full textSubdivision schemes are used to generate smooth curves or surfaces by iteratively refining an initial control polygon or mesh. We focus on univariate, linear, binary subdivision schemes, where the vertices of the refined polygon are computed as linear combinations of the current neighbouring vertices. In the classical stationary setting, there are just two such subdivision rules, which are used throughout all subdivision steps to construct the new vertices with even and odd indices, respectively. These schemes are well understood and many tools have been developed for deriving their properties, including the smoothness of the limit curves. For non-stationary schemes, the subdivision rules are not fixed and can be different in each subdivision step. Non-uniform schemes are even more general, as they allow the subdivision rules to be different for every new vertex that is generated by the scheme. The properties of non-stationary and non-uniform schemes are usually derived by relating the scheme to a corresponding stationary scheme and then exploiting the fact that the properties of the stationary scheme carry over under certain proximity conditions. In particular, this approach can be used to show that the limit curves of a non-stationary or non-uniform scheme are as smooth as those of a corresponding stationary scheme. In this paper we show that non-uniform subdivision schemes have the potential to generate limit curves that are smoother than those of stationary schemes with the same support size of the subdivision rule. For that, we derive interpolatory 2-point and 4-point schemes that generate C-1 and C-2 limit curves, respectively. These values of smoothness exceed the smoothness of classical interpolating schemes with the same support size by one. (C) 2022 The Author(s). Published by Elsevier B.V
Practical Computation of the Cut Locus on Discrete Surfaces
No full textWe present a novel method to compute the cut locus of a distance function encoded on a polygonal mesh. Our method exploits theoretical findings about the cut locus and – with a combination of analytic, geometric and topological tools – it is able to compute a topologically correct and geometrically accurate approximation of it. Our result can be either restricted to the mesh edges, or aligned with the real cut locus. Both outputs may be useful for practical applications. We also provide a convenient tool to optionally prune the weak branches of the cut locus, simplifying its structure. Our approach supersedes prior art, in that it is easier to use and also orders of magnitude faster. In fact, it depends on just one parameter, and it flawlessly operates on meshes with high genus and very high element count at interactive rates. We experiment with different datasets and methods for geodesic distance estimation. We also present applications to local and global surface parameterization
A comparison of methods for gradient field estimation on simplicial meshes
No full textThe estimation of the differential properties of a function sampled at the vertices of a discrete domain is at the basis of many applied sciences. In this paper, we focus on the computation of function gradients on triangle and tetrahedral meshes. We study one cell-based method (the standard the facto), plus three vertex-based methods. Comparisons regard accuracy, ability to perform on different domain discretizations, and efficiency. We performed extensive tests and provide an in-depth analysis of our results. Besides some common behaviour, we found that some methods perform better than others, considering both accuracy and efficiency. This directly translates to useful suggestions for the implementation of gradient estimators in research and industrial code
Da Gutemberg a Google Print: l'Accademia delle Scienze di Torino e l'evoluzione dell'ICT del patrimonio culturale.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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