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75
Spherical Wavelets: Efficiently Representing Functions on the Sphere
, 1995
"... Wavelets have proven to be powerful bases for use in numerical analysis and signal processing. Their power lies in the fact that they only require a small number of coefficients to represent general functions and large data sets accurately. This allows compression and efficient computations. Classic ..."
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Cited by 286 (14 self)
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Wavelets have proven to be powerful bases for use in numerical analysis and signal processing. Their power lies in the fact that they only require a small number of coefficients to represent general functions and large data sets accurately. This allows compression and efficient computations. Classical constructions have been limited to simple domains such as intervals and rectangles. In this paper we present a wavelet construction for scalar functions defined on the sphere. We show how biorthogonal wavelets with custom properties can be constructed with the lifting scheme. The bases are extremely easy to implement and allow fully adaptive subdivisions. We give examples of functions defined on the sphere, such as topographic data, bidirectional reflection distribution functions, and illumination, and show how they can be efficiently represented with spherical wavelets.
NonLinear Approximation of Reflectance Functions
, 1997
"... We introduce a new class of primitive functions with nonlinear parameters for representing light reflectance functions. The functions are reciprocal, energyconserving and expressive. They can capture important phenomena such as offspecular reflection, increasing reflectance and retroreflection. ..."
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Cited by 269 (10 self)
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We introduce a new class of primitive functions with nonlinear parameters for representing light reflectance functions. The functions are reciprocal, energyconserving and expressive. They can capture important phenomena such as offspecular reflection, increasing reflectance and retroreflection. We demonstrate this by fitting sums of primitive functions to a physicallybased model and to actual measurements. The resulting representation is simple, compact and uniform. It can be applied efficiently in analytical and Monte Carlo computations. CR Categories: I.3.7 [Computer Graphics]: ThreeDimensional Graphics and Realism; I.3.3 [Computer Graphics]: Picture/Image Generation Keywords: Reflectance function, BRDF representation 1 INTRODUCTION The bidirectional reflectance distribution function (BRDF) of a material describes how light is scattered at its surface. It determines the appearance of objects in a scene, through direct illumination and global interreflection effects. Local r...
Computergenerated watercolor,”
 in Proceedings of the 24th annual conference on Computer graphics and interactive techniques (SIGGRAPH ’97),
, 1997
"... Abstract This paper describes the various artistic effects of watercolor and shows how they can be simulated automatically. Our watercolor model is based on an ordered set of translucent glazes, which are created independently using a shallowwater fluid simulation. We use a KubelkaMunk compositin ..."
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Cited by 145 (2 self)
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Abstract This paper describes the various artistic effects of watercolor and shows how they can be simulated automatically. Our watercolor model is based on an ordered set of translucent glazes, which are created independently using a shallowwater fluid simulation. We use a KubelkaMunk compositing model for simulating the optical effect of the superimposed glazes. We demonstrate how computergenerated watercolor can be used in three different applications: as part of an interactive watercolor paint system, as a method for automatic image "watercolorization,"and as a mechanism for nonphotorealistic rendering of threedimensional scenes.
Interactive Rendering with Arbitrary BRDFs using Separable Approximations
 IN EUROGRAPHICS RENDERING WORKSHOP
, 1999
"... A separable decomposition of bidirectional reflectance distributions (BRDFs) is used to implement arbitrary reflectances from point sources on existing graphics hardware. Twodimensional texture mapping and compositing operations are used to reconstruct samples of the BRDF at every pixel at interact ..."
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Cited by 133 (19 self)
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A separable decomposition of bidirectional reflectance distributions (BRDFs) is used to implement arbitrary reflectances from point sources on existing graphics hardware. Twodimensional texture mapping and compositing operations are used to reconstruct samples of the BRDF at every pixel at interactive rates. A change of variables, the GramSchmidt halfangle/difference vector parameterization, improves separability. Two decomposition algorithms are also presented. The singular value decomposition (SVD) minimizes RMS error. The normalized decomposition is fast and simple, using no more space than what is required for the final representation.
Homomorphic factorization of brdfs for highperformance rendering
, 2001
"... Figure 1: A model rendered at realtime rates (approximately half the performance of the standard pervertex lighting model on an NVIDIA GeForce 3) with several BRDFs approximated using the technique in this paper. From left to right: satin (anisotropic PoulinFournier model), krylon blue, garnet re ..."
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Cited by 101 (7 self)
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Figure 1: A model rendered at realtime rates (approximately half the performance of the standard pervertex lighting model on an NVIDIA GeForce 3) with several BRDFs approximated using the technique in this paper. From left to right: satin (anisotropic PoulinFournier model), krylon blue, garnet red, cayman, mystique (Cornell measured data), leather, and velvet (CURET measured data). A bidirectional reflectance distribution function (BRDF) describes how a material reflects light from its surface. To use arbitrary BRDFs in realtime rendering, a compression technique must be used to represent BRDFs using the available texturemapping and computational capabilities of an accelerated graphics pipeline. We present a numerical technique, homomorphic factorization, that can decompose arbitrary BRDFs into products of two or more factors of lower dimensionality, each factor dependent on a different interpolated geometric parameter. Compared to an earlier factorization technique based on the singular value decomposition, this new technique generates a factorization with only positive factors (which makes it more suitable for current graphics hardware accelerators), provides control over the smoothness of the result, minimizes relative rather than absolute error, and can deal with scattered, sparse data without a separate resampling and interpolation algorithm.
A Microfacetbased BRDF Generator
, 2000
"... A method is presented that takes as an input a 2D microfacet orientation distribution and produces a 4D bidirectional reflectance distribution function (BRDF). This method differs from previous microfacetbased BRDF models in that it uses a simple shadowing term which allows it to handle very genera ..."
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Cited by 95 (3 self)
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A method is presented that takes as an input a 2D microfacet orientation distribution and produces a 4D bidirectional reflectance distribution function (BRDF). This method differs from previous microfacetbased BRDF models in that it uses a simple shadowing term which allows it to handle very general microfacet distributions while maintaining reciprocity and energy conservation. The generator is shown on a variety of material types.
Reflection Space Image Based Rendering
, 1999
"... High quality, physically accurate rendering at interactive rates has widespread application, but is a daunting task. We attempt to bridge the gap between highquality offline and interactive rendering by using existing environment mapping hardware in combination with a novel Image Based Rendering (I ..."
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Cited by 87 (1 self)
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High quality, physically accurate rendering at interactive rates has widespread application, but is a daunting task. We attempt to bridge the gap between highquality offline and interactive rendering by using existing environment mapping hardware in combination with a novel Image Based Rendering (IBR) algorithm. The primary contribution lies in performing IBR in reflection space. This method can be applied to ordinary environment maps, but for more physically accurate rendering, we apply reflection space IBR to radiance environment maps. A radiance environment map preintegrates a Bidirectional Reflection Distribution Function (BRDF) with a lighting environment. Using the reflectionspace IBR algorithm on radiance environment maps allows interactive rendering of arbitrary objects with a large class of complex BRDFs in arbitrary lighting environments. The ultimate simplicity of the final algorithm suggests that it will be widely and immediately valuable given the ready availability of hardware assisted environment mapping.
Diffraction Shaders
, 1999
"... The reflection of light from surfaces is a fundamental problem in computer graphics. Although many reflection models have been proposed, few take into account the wave nature of light. In this paper, we derive a new class of reflection models for metallic surfaces that handle the effects of diffract ..."
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Cited by 58 (0 self)
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The reflection of light from surfaces is a fundamental problem in computer graphics. Although many reflection models have been proposed, few take into account the wave nature of light. In this paper, we derive a new class of reflection models for metallic surfaces that handle the effects of diffraction. Diffraction is a purely wavelike phenomenon and cannot be properly modeled using the ray theory of light alone. A common example of a surface which exhibits diffraction is the compact disk. A characteristic of such surfaces is that they reflect light in a very colorful manner. Our model is also a generalization of most reflection models encountered in computer graphics. In particular, we extend the HeTorrance model to handle anisotropic reflections. This is achieved by rederiving, in a more general setting, results from surface wave physics which were taken for granted by other researchers. Specifically, our use of Fourier analysis has enabled us to tackle the difficult task of analytically computing the Kirchhoff integral of surface scattering.
Uniformly Sampled Light Fields
, 1998
"... Imagebased or light field rendering has received much recent attention as an alternative to traditional geometric methods for modeling and rendering complex objects. A light field represents the radiance flowing through all the points in a scene in all possible directions. We explore two new techni ..."
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Cited by 50 (4 self)
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Imagebased or light field rendering has received much recent attention as an alternative to traditional geometric methods for modeling and rendering complex objects. A light field represents the radiance flowing through all the points in a scene in all possible directions. We explore two new techniques for efficiently acquiring, storing, and reconstructing light fields in a (nearly) uniform fashion. Both techniques sample the light field by sampling the set of lines that intersect a sphere tightly fit around a given object. Our first approach relies on uniformly subdividing the sphere and representing this subdivision in a compact data structure which allows efficient mapping of image pixels or rays to sphere points and then to subdivision elements. We sample a light field by joining pairs of subdivision elements and store the resulting samples in a multiresolution, highly compressed fashion that allows efficient rendering. Our second method allows a uniform sampling of all five dime...
Tone reproduction and physically based spectral rendering
 in [State of the Art Reports, Eurographics 2002
, 2002
"... ..."