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/).
This article presents information on how to solve cubic equations. The conventional version of the problem is to find the roots of the equation. Four things can happen with cubic polynomial roots. These consists of th...
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This article presents information on how to solve cubic equations. The conventional version of the problem is to find the roots of the equation. Four things can happen with cubic polynomial roots. These consists of the various permutations of multiple roots and imaginary roots. Therefore, the notation for the type code is a concatenation of the multiplicity counts for the various roots. Some computer graphics intuition about homogeneous coordinates can be used to project the homogeneous 4D space into a 3D space that includes a plane at infinity.
The paper presents a new shadow testing acceleration scheme for ray tracing called hybrid shadow testing (HST) based on conditional switching between the conventional shadow testing method and Crow's shadow volume...
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The paper presents a new shadow testing acceleration scheme for ray tracing called hybrid shadow testing (HST) based on conditional switching between the conventional shadow testing method and Crow's shadow volume method, where the shadow polygons as well as the object polygons are registered onto the corresponding cells under the 3D space subdivision environment. Despite the preprocessing time needed for the generation and registration of the shadow polygons, the total shadow testing time of HST was approximately 50% of that of conventional shadow testing for several examples, while the total ray tracing time was typically reduced by 30%. This is due to the selective use of the shadow volume method, with a compromise between maximizing use of the shadow's spatial coherency and minimizing the computational overhead for checking ray intersections with the shadow polygons. A parameter N th , denoting the critical number of shadow polygons between successive reflection points, was used as a guideline for switching the shadow testing scheme between the conventional method and shadow volume method. A method for calculating N th from statistical data such as the number of object polygons, average polygon size, and average peripheral length of the polygons was proposed, resulting in good agreement with the experimental results.
Two decades have passed since the introduction of Markov chain Monte Carlo (MCMC) into light transport simulation by Veach and Guibas, and numerous follow-up works have been published since then. However, up until now...
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Two decades have passed since the introduction of Markov chain Monte Carlo (MCMC) into light transport simulation by Veach and Guibas, and numerous follow-up works have been published since then. However, up until now no survey has attempted to cover the majority of these methods. The aim of this paper is therefore to offer a first comprehensive survey of MCMC algorithms for light transport simulation. The methods presented in this paper are categorized by their objectives and properties, while we point out their strengths and weaknesses. We discuss how the methods handle the main issues of MCMC and how they could be combined or improved in the near future. To make the paper suitable for readers unacquainted with MCMC methods, we include an introduction to general MCMC and its demonstration on a simple example.
This approach uses a focused plenoptic camera to capture the plenoptic function's rich 'non 3D' structure. It employs two techniques. The first simultaneously captures multiple exposures (or other aspects)...
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This approach uses a focused plenoptic camera to capture the plenoptic function's rich 'non 3D' structure. It employs two techniques. The first simultaneously captures multiple exposures (or other aspects) based on a microlens array having an interleaved set of different filters. The second places multiple filters at the main lens aperture.
作者：
Hart, JCSchool of EECS
Washington State University Pullman WA 99164-2752 hart@eecs.wsu.edu
Implicit surface techniques provide useful tools for modeling and rendering smooth surfaces. Deriving implicit formulations for fractal representations extends the scope of implicit surface techniques to rough surface...
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Implicit surface techniques provide useful tools for modeling and rendering smooth surfaces. Deriving implicit formulations for fractal representations extends the scope of implicit surface techniques to rough surfaces. Linear fractals modeled by recurrent iterated function systems may be defined implicitly using either geometric distance or escape time. Random fractals modeled using Pel lin's noise function are already defined implicitly when described as ''hypertexture.'' Deriving new implicit formulae is only the first step. Unlike their smooth counterparts, rough implicit surfaces require special rendering techniques that do not rely on continuous differentiation of the defining function. Preliminary experiments applying blending operations to rough surfaces have succeeded in an initial attempt to overcome current challenges in natural modeling. The grafting of a stem onto the base of a linear fractal leaf continuously blends smooth detail into rough detail. The blend of two textured cylinders interpolates geometric bark across branching points in a tree.
Interactive performance is one of the most innovative ways computers can beused in music, and it leads to new ways of thinking about music composition and *** performance also poses many technical challenges, resultin...
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Interactive performance is one of the most innovative ways computers can beused in music, and it leads to new ways of thinking about music composition and *** performance also poses many technical challenges, resulting in new languages and specialhardware including sensors, synthesis methods, and software techniques. As if there are not alreadyenough problems to tackle, many composers and artists have explored the combination of computeranimation and music within interactive performances. In this article, I describe my own work in thisarea, dating from around 1987, including discussions of artistic and technical challenges as theyhave evolved. I also describe the Aura system, which I now use to create interactive music,animation, and video. My main interest in composing and developing systems is to approach music andvideo as expressions of the same underlying musical 'deep structure.' Thus, images are not aninterpretation or accompaniment to audio but rather an integral part of the music and thelistener/viewer experience. From a systems perspective, I have always felt that timing andresponsiveness are critical if images and music are to work together. I have focused on softwareorganizations that afford precise timing and flexible interaction, sometimes at the expense of richimagery or more convenient tools for image-making.
Starlike surfaces can be defined in spherical coordinates by a function r( theta , phi ) on the unit sphere, which can be expanded in spherical harmonics to give a consequence of smooth approximations to the surface. ...
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Starlike surfaces can be defined in spherical coordinates by a function r( theta , phi ) on the unit sphere, which can be expanded in spherical harmonics to give a consequence of smooth approximations to the surface. This method has been used to approximate the solvent-accessible surface of a molecule. The coefficients in the expansion provide a small collection of numbers that characterize the molecular shape. The resulting smooth surfaces can be rendered with random dots or smooth shading. These spherical harmonic surfaces have advantages for modeling overall molecular shape, particularly time-averaged shapes relevant to electrostatic and other intermolecular interactions.
Perceptually based colour spaces, colour order systems and colour naming systems based on natural language categories are being increasingly applied to the specification of colour appearance of colour VDUs. Since the ...
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Perceptually based colour spaces, colour order systems and colour naming systems based on natural language categories are being increasingly applied to the specification of colour appearance of colour VDUs. Since the Natural Colour System (NCS) is defined according to fundamental attributes of colour perception and the NCS colour notations agree well with cognitive and linguistic aspects of colour, the NCS is very convenient for colour selection in human-computer interaction. However, VDU colours have not earlier been visually presented as a virtual NCS colour atlas with coloured patches occupying the appropriate positions in the NCS colour space. In this paper, the NCS is illustrated by displaying the colour stimuli of 4 096 digital RGB combinations into NCS colour triangles representing 80 different NCS hues.
This paper reviews an approach which is becoming increasing common for Operational Research applications. The approach is known as Visual Interactive Modelling. It consists of first developing suitable visually animat...
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This paper reviews an approach which is becoming increasing common for Operational Research applications. The approach is known as Visual Interactive Modelling. It consists of first developing suitable visually animated graphics displays for the application under investigation. These displays supported by appropriate man-machine dialogues and models allow both analysts and users to explore dynamics of the application and thus gain an insight into its likely operational characteristics. This paper reviews the types of model, interactive dialogue and animated displays found in current visual interactive modelling applications. [ABSTRACT FROM AUTHOR]
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