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108
Precomputed Radiance Transfer for RealTime Rendering in Dynamic, LowFrequency Lighting Environments
 ACM Transactions on Graphics
, 2002
"... We present a new, realtime method for rendering diffuse and glossy objects in lowfrequency lighting environments that captures soft shadows, interreflections, and caustics. As a preprocess, a novel global transport simulator creates functions over the object's surface representing transfer of arbi ..."
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Cited by 358 (23 self)
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We present a new, realtime method for rendering diffuse and glossy objects in lowfrequency lighting environments that captures soft shadows, interreflections, and caustics. As a preprocess, a novel global transport simulator creates functions over the object's surface representing transfer of arbitrary, lowfrequency incident lighting into transferred radiance which includes global effects like shadows and interreflections from the object onto itself. At runtime, these transfer functions are applied to actual incident lighting. Dynamic, local lighting is handled by sampling it close to the object every frame; the object can also be rigidly rotated with respect to the lighting and vice versa. Lighting and transfer functions are represented using loworder spherical harmonics. This avoids aliasing and evaluates efficiently on graphics hardware by reducing the shading integral to a dot product of 9 to 25 element vectors for diffuse receivers. Glossy objects are handled using matrices rather than vectors. We further introduce functions for radiance transfer from a dynamic lighting environment through a preprocessed object to neighboring points in space. These allow soft shadows and caustics from rigidly moving objects to be cast onto arbitrary, dynamic receivers. We demonstrate realtime global lighting effects with this approach.
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 229 (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.
Global Illumination using Photon Maps
, 1996
"... This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy ..."
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Cited by 217 (9 self)
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This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy (photons) from the light sources and storing these as they hit surfaces within the scene. We use one high resolution caustics photon map to render caustics that are visualized directly and one low resolution photon map that is used during the rendering step. The scene is rendered using a distribution ray tracing algorithm optimized by using the information in the photon maps. Shadow photons are used to render shadows more efficiently and the directional information in the photon map is used to generate optimized sampling directions and to limit the recursion in the distribution ray tracer by providing an estimate of the radiance on all surfaces with the exception of specular...
A SignalProcessing Framework for Inverse Rendering
 In SIGGRAPH 01
, 2001
"... Realism in computergenerated images requires accurate input models for lighting, textures and BRDFs. One of the best ways of obtaining highquality data is through measurements of scene attributes from real photographs by inverse rendering. However, inverse rendering methods have been largely limit ..."
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Cited by 189 (18 self)
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Realism in computergenerated images requires accurate input models for lighting, textures and BRDFs. One of the best ways of obtaining highquality data is through measurements of scene attributes from real photographs by inverse rendering. However, inverse rendering methods have been largely limited to settings with highly controlled lighting. One of the reasons for this is the lack of a coherent mathematical framework for inverse rendering under general illumination conditions. Our main contribution is the introduction of a signalprocessing framework which describes the reflected light field as a convolution of the lighting and BRDF, and expresses it mathematically as a product of spherical harmonic coefficients of the BRDF and the lighting. Inverse rendering can then be viewed as deconvolution. We apply this theory to a variety of problems in inverse rendering, explaining a number of previous empirical results. We will show why certain problems are illposed or numerically illconditioned, and why other problems are more amenable to solution. The theory developed here also leads to new practical representations and algorithms. For instance, we present a method to factor the lighting and BRDF from a small number of views, i.e. to estimate both simultaneously when neither is known.
An Efficient Representation for Irradiance Environment Maps
, 2001
"... We consider the rendering of diffuse objects under distant illumination, as specified by an environment map. Using an analytic expression for the irradiance in terms of spherical harmonic coefficients of the lighting, we show that one needs to compute and use only 9 coefficients, corresponding to th ..."
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Cited by 160 (10 self)
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We consider the rendering of diffuse objects under distant illumination, as specified by an environment map. Using an analytic expression for the irradiance in terms of spherical harmonic coefficients of the lighting, we show that one needs to compute and use only 9 coefficients, corresponding to the lowestfrequency modes of the illumination, in order to achieve average errors of only 1%. In other words, the irradiance is insensitive to high frequencies in the lighting, and is well approximated using only 9 parameters. In fact, we show that the irradiance can be procedurally represented simply as a quadratic polynomial in the cartesian components of the surface normal, and give explicit formulae. These observations lead to a simple and efficient procedural rendering algorithm amenable to hardware implementation, a prefiltering method up to three orders of magnitude faster than previous techniques, and new representations for lighting design and imagebased rendering.
P.: A Comprehensive Physical Model for Light Reflection
 In Proc. of SIGGRAPH
, 1991
"... A new general reflectance model for computer graphics is presented. The model is based on physical optics and describes specular, directional diffuse, and uniform diffuse reflection by a surface. The reflected light pattern depends on wavelength, incidence angle, two surface roughness parameters. an ..."
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Cited by 154 (7 self)
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A new general reflectance model for computer graphics is presented. The model is based on physical optics and describes specular, directional diffuse, and uniform diffuse reflection by a surface. The reflected light pattern depends on wavelength, incidence angle, two surface roughness parameters. and surface refractive index. The formulation is self consistent in terms of polarization, surface roughness,
Polynomial texture maps
 In Computer Graphics, SIGGRAPH 2001 Proceedings
, 2001
"... graphics hardware, illumination, image processing, imagebased rendering, reflectance & shading models, texture mapping In this paper we present a new form of texture mapping that produces increased photorealism. Coefficients of a biquadratic polynomial are stored per texel, and used to reconstruct ..."
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Cited by 129 (8 self)
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graphics hardware, illumination, image processing, imagebased rendering, reflectance & shading models, texture mapping In this paper we present a new form of texture mapping that produces increased photorealism. Coefficients of a biquadratic polynomial are stored per texel, and used to reconstruct the surface color under varying lighting conditions. Like bump mapping, this allows the perception of surface deformations. However, our method is image based, and photographs of a surface under varying lighting conditions can be used to construct these maps. Unlike bump maps, these Polynomial Texture Maps (PTMs) also capture variations due to surface selfshadowing and interreflections, which enhance realism. Surface colors can be efficiently reconstructed from polynomial coefficients and light directions with minimal fixedpoint hardware. We have also found PTMs useful for producing a number of other effects such as anisotropic and Fresnel shading models and variable depth of focus. Lastly, we present several reflectance function transformations that act as contrast enhancement operators. We have found these particularly useful in the study of ancient archeological clay and stone writings.
BiDirectional Path Tracing
 PROCEEDINGS OF THIRD INTERNATIONAL CONFERENCE ON COMPUTATIONAL GRAPHICS AND VISUALIZATION TECHNIQUES (COMPUGRAPHICS ’93
, 1993
"... In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of ..."
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Cited by 127 (10 self)
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In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of
On the relationship between radiance and irradiance: determining the illumination from images of a convex Lambertian object
, 2001
"... This paper presents a theoretical analysis of the relationship between incoming radiance and irradiance. Radiance and irradiance are basic optical quantities, and their relationship is of fundamental interest to many fields, including computer vision, radiative transfer, and computer graphics. Physi ..."
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Cited by 117 (10 self)
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This paper presents a theoretical analysis of the relationship between incoming radiance and irradiance. Radiance and irradiance are basic optical quantities, and their relationship is of fundamental interest to many fields, including computer vision, radiative transfer, and computer graphics. Physically, we are interested in analyzing the properties of the light field generated when a homogeneous convex curved Lambertian surface of known geometry reflects a distant illumination field. A Lambertian surface reflects light proportional to the incoming irradiance, so analysis of this physical system is equivalent to a mathematical analysis of the relationship between incoming radiance and irradiance
A unified hierarchical algorithm for global illumination with scattering volumes and object clusters
 IEEE Trans. Vis. Comput. Graph
, 1995
"... Abstract — This paper presents a new radiosity algorithm that allows the simultaneous computation of energy exchanges between surface elements, scattering volume distributions, and groups of surfaces, or object clusters. The new technique is based on a hierarchical formulation of the zonal method, a ..."
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Cited by 106 (22 self)
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Abstract — This paper presents a new radiosity algorithm that allows the simultaneous computation of energy exchanges between surface elements, scattering volume distributions, and groups of surfaces, or object clusters. The new technique is based on a hierarchical formulation of the zonal method, and efficiently integrates volumes and surfaces. In particular no initial linking stage is needed, even for inhomogeneous volumes, thanks to the construction of a global spatial hierarchy. An analogy between object clusters and scattering volumes results in a powerful clustering radiosity algorithm, with no initial linking between surfaces and fast computation of average visibility information through a cluster. We show that the accurate distribution of the energy emitted or received at the cluster level can produce even better results than isotropic clustering at a marginal cost. The resulting algorithm is fast and, more importantly, truly progressive as it allows the quick calculation of approximate solutions with a smooth convergence towards very accurate simulations. I.