To overcome the well-known shape deficiencies of bi-cubic subdivision surfaces, Evolving Guide subdivision (EG subdivision) generalizes C-2 bi-quartic (bi-4) splines that approximate a sequence of piecewise polynomial...
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To overcome the well-known shape deficiencies of bi-cubic subdivision surfaces, Evolving Guide subdivision (EG subdivision) generalizes C-2 bi-quartic (bi-4) splines that approximate a sequence of piecewise polynomial surface pieces near extraordinary points. Unlike guided subdivision, which achieves good shape by following a guide surface in a two-stage, geometry-dependent process, EG subdivision is defined by five new explicit subdivision rules. While formally only C-1 at extraordinary points, EG subdivision applied to an obstacle course of inputs generates surfaces without the oscillations and pinched highlight lines typical for Catmull-Clark subdivision. EG subdivision surfaces join C-2 with bi-3 surface pieces obtained by interpreting regular sub-nets as bi-cubic tensor-product splines and C-2 with adjacent EG surfaces. The EG subdivision control net surrounding an extraordinary node can have the same structure as Catmull-Clark subdivision: two rings of 4-sided facets around each extraordinary nodes so that extraordinary nodes are separated by at least one regular node.
Wearable antennas can suffer from a variety of mechanical deformations that are induced by the body dynamic. The article analyses how these complex deformations impact the performance of a flexible antenna operating i...
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Wearable antennas can suffer from a variety of mechanical deformations that are induced by the body dynamic. The article analyses how these complex deformations impact the performance of a flexible antenna operating in the 5-6 GHz band. The Green Coordinates (GC) spatial manipulation technique is used to generate a range of complex 2-D deformations, namely spherical, saddle, and twisting deformation. Generating full geometries is a key enabler in this study. The results offer valuable insight into the stability of antenna performance under in situ deformations.
computer graphics research frequently evaluates research outputs with user studies, often through online crowdworking platforms. When performed carefully and thoughtfully, studies on human behavior and preferences pro...
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computer graphics research frequently evaluates research outputs with user studies, often through online crowdworking platforms. When performed carefully and thoughtfully, studies on human behavior and preferences provide valuable insights, useful for both developing and evaluating new tools. Yet, I argue that many of the current studies are performative: they result from reviewers' expectation that "papers should have some evaluation," not from careful thought about the value and usefulness of the studies themselves. These casually done studies are often uninformative or misleading, while putting undue burden on authors and reviewers. The expectation of positive user evaluation results can also inhibit creative new work. I call for reviewers to be more thoughtful about asking for user studies, for authors to be more thoughtful when they perform studies, and for our field to conduct new research and create new guidelines on when and how user studies are genuinely useful.
Digital color restitution aims to digitally restore the original colors of a painting. Existing image editing applications can be used for this purpose, but they require a select-and-edit workflow and thus they do not...
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Digital color restitution aims to digitally restore the original colors of a painting. Existing image editing applications can be used for this purpose, but they require a select-and-edit workflow and thus they do not scale well to large collections of paintings or different regions of the same painting. To address this issue, we propose an automated workflow that requires only a few representative source colors and associated target colors as input from art historians. The system then creates a control grid to model a deformation of the CIELAB color space. Such deformation can be applied to arbitrary images of the same painting. The proposed approach is suitable for restituting the color of images from a large photographic campaign, as well as for the textures of 3D reconstructions of a monument. We demonstrate the benefits of our method on a collection of mural paintings from a medieval monument. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://***/licenses/by/4.0/).
Curve approximation is a challenging issue to precisely depict exquisite shapes of natural phenomena, in which the piecewise Bezier curve is one of the most widely utilized tools due to its beneficial properties. It i...
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Curve approximation is a challenging issue to precisely depict exquisite shapes of natural phenomena, in which the piecewise Bezier curve is one of the most widely utilized tools due to its beneficial properties. It is essential to determine the quantity and location of control points through the process of generating the mathematical representation of desired objects. This paper presents a new algorithm called adaptive extension fitting scheme (AEFS) to determine a piecewise Bezier curve that best fits a given sequence of data points as well as locate the coordinates of the connecting points between the pieces adaptively. Taking full advantage of the scalability of the Bezier curve segment, AEFS is effective in sequential knot searching within an impressively small computational consumption. The capability of the proposed stepwise extension strategy is deduced from rigorous theoretical proof, resulting in proper connecting points together with well-fitted Bezier curves. The proposed algorithm is evaluated by some popular benchmarks for curve fitting, and compared with several state-of-the-art approaches. Experimental results indicate that AEFS outperforms other models involved in terms of execution time, fitting accuracy, number of segments, and the authenticity of shape contours.
Diffusion magnetic resonance imaging quantifies the diffusion of water molecules. It is unique in showing white matter fiber structures and connectivity in-vivo, relying on the fact that the water molecules' displ...
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Diffusion magnetic resonance imaging quantifies the diffusion of water molecules. It is unique in showing white matter fiber structures and connectivity in-vivo, relying on the fact that the water molecules' displacements are more significant along with the fiber orientation than in other directions due to biological barriers. High angular resolution diffusion imaging (HARDI) acquisition enables the differentiation of multiple fiber signals passing through a voxel. Advanced methods for processing diffusion data were developed to synthesize the HARDI data of each voxel into an orientation distribution function (ODF) that relates each direction sample to its probability of water diffusion. Visualizing ODFs through glyphs helps gain insight into the local structure of the brain white matter. Because of the high dimensionality of the data, interactive glyph exploration remains a challenge for a volume containing millions of voxels. This work presents a 3D triangle-based multi-resolution rendering scheme for the ODF glyph. We explored data properties and GPU features to make the triangle-based rendering interactive. Linear performance relative to some fixed-resolution rendered glyphs was assessed using NVIDIA (R) Nsight Visual StudioTM. A control volume, available in the Retest dataset of the WU-Minn Human Connectome Project, was used to assess the effectiveness of interactive 3D visualization over a multiplanar and curvilinear reformatted volume of ODF glyphs in voxels with multiple fibers, namely the triple crossing at the centrum semiovale, the fanning at the corona radiata, and the crossing of the cingulum and corpus callosum fiber bundles.(c) 2023 Elsevier Ltd. All rights reserved.
The perception of realism in computer-generated images can be significantly enhanced by subtle visual cues. Among those, one can highlight the presence of dust on synthetic objects, which is often subject to temporal ...
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The perception of realism in computer-generated images can be significantly enhanced by subtle visual cues. Among those, one can highlight the presence of dust on synthetic objects, which is often subject to temporal variations in real settings. In this paper, we present a framework for the generation of textures representing the accumulation of this ubiquitous material over time in indoor settings. It employs a physically inspired approach to portray the effects of different levels of accumulated dust roughness on the appearance of substrate surfaces and to modulate these effects according to the different illumination and viewing geometries. The development of its core algorithms was guided by empirical insights and data obtained from observational experiments which are also described. To illustrate its applicability to the rendering of visually plausible depictions of time-dependent changes in dusty scenes, we provide sequences of images obtained considering distinct dust accumulation scenarios.
Immersive Virtual Reality (IVR) provides a platform where the real world can be replicated to a point where users can act and react in the virtual world as they would in reality. However, rendering visual stimuli is c...
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Immersive Virtual Reality (IVR) provides a platform where the real world can be replicated to a point where users can act and react in the virtual world as they would in reality. However, rendering visual stimuli is computationally heavy. Thus, optimizations must be done to take advantage of computational systems by studying our perception of reality. This study investigated parameters related to light rendering (Global Illumination, Ambient Occlusion, Screen Space Reflections (SSR) and Direct Shadows) in real-time in a virtual replica of a real place using IVR. Participants experienced both virtual and real rooms with only one flashlight and changed the quality settings of the considered parameters so that their sense of reality would be the closest to the one they felt when they experienced the real room. Participants were given a budget to drive them to prioritize what parameters, and their level of quality, are the most important for their sense of reality. Results indicated that participants considered Global Illumination the most important factor, closely followed by Direct Shadows. Ambient Occlusion and Reflections (Screen Space Reflections) were the less prioritized parameters. We conclude that in a lighting setting where only dynamic lights are used, Global Illumination and Direct Shadows should be prioritized over SSR Reflections and Ambient Occlusion when computational power is limited.
During the last decades, innovative aircraft health management systems have been receiving increasing interest from original equipment manufacturers (OEMs) and aircraft operators. Their implementation could lead to su...
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During the last decades, innovative aircraft health management systems have been receiving increasing interest from original equipment manufacturers (OEMs) and aircraft operators. Their implementation could lead to substantial benefits: drastic cuts in turnaround time, operation costs, and life cycle costs (LCCs) as well as sharp increases in system availability, safety, and reliability. An interconnectivity step-up is, hence, needed to guarantee a seamless data transfer. In this article, an integrated open-source solution for reliable data transmission and near real-time graphical visualization is proposed. After a comprehensive calibration and verification campaign performed on a test stand, the overall system has been successfully validated on structural data measured using a network of fiber Bragg gratings (FBGs) mounted on a radio-controlled model aircraft. The result is an effective and robust system able to monitor near real-time critical parameters and health status of structures. With this system, the temperature and displacements of the structure can be displayed on a heat map arranged on a 3-D model and visualized through a computer application on the ground. The proposed methodology can be applied to heterogeneous scenarios, ranging from maintenance planning activities to performance checks, providing an all-in-one solution for flight data management as well as other applications in the structural monitoring domain.
Motion graphics authoring is a time-intensive endeavor, demanding proficiency in various feature-rich software. Automated, example-based solutions are now being explored to simplify the motion graphics creation proces...
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ISBN:
(纸本)9798400704857
Motion graphics authoring is a time-intensive endeavor, demanding proficiency in various feature-rich software. Automated, example-based solutions are now being explored to simplify the motion graphics creation process. To investigate how such streamlined authoring tools impact motion designers' workflows and perceptions of creativity, we deployed an end-to-end motion graphics authoring tool to 14 users, spanning casual to professional design expertise. Our key findings reveal a dichotomy: casual designers embraced the tool's automation, finding empowerment in its simplicity, even at the expense of losing narrative control. Conversely, professionals expressed reservations and raised concerns about the trade-offs between efficiency and creative autonomy. Notably, the level of automation in animation emerged as a point of contention, under-scoring differing expectations between the two groups. Our work contributes insights into such nuances, offering implications for designing the next generation of motion graphics authoring tools that cater to a broad spectrum of creative aspirations and abilities.
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