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50
Importance Driven Construction of Photon Maps
 In Rendering Techniques ’98 (Proceedings of the 9th Eurographics Workshop on Rendering
, 1998
"... . Particle tracing allows physically correct simulation of all kinds of light interaction in a scene, but can be a computationally expensive task. Use of visual importance is a powerful technique to improve the efficiency of global illumination calculations. We describe a three pass solution for glo ..."
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Cited by 31 (0 self)
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. Particle tracing allows physically correct simulation of all kinds of light interaction in a scene, but can be a computationally expensive task. Use of visual importance is a powerful technique to improve the efficiency of global illumination calculations. We describe a three pass solution for global illumination calculation extending the two pass approach proposed by Jensen. In the first pass particle tracing of importance is performed to create a global data structure, called importance map. Based on this data structure importance driven photon tracing is used in the second pass to construct a photon map containing information about the global illumination in the scene. In the last pass the image is rendered by distributed ray tracing using the photon map. The photon tracing process, improved by the use of importance information, creates photon maps with an up to 8times higher photon density in important regions of the scene. This allows a better use of memory and computation time...
Efficient Importance Sampling Techniques for the Photon Map
, 2000
"... In global illumination computations the photon map is a powerful tool for approximating the irradiance, which is stored independent from scene geometry. By presenting a new algorithm, which uses novel importance sampling techniques, we improve the memory footprint of the photon map, simplify the cau ..."
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Cited by 30 (5 self)
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In global illumination computations the photon map is a powerful tool for approximating the irradiance, which is stored independent from scene geometry. By presenting a new algorithm, which uses novel importance sampling techniques, we improve the memory footprint of the photon map, simplify the caustic generation, and allow for a much faster sampling of direct illumination in complicated models as they arise in a production environment.
Density Control for Photon Maps
 In Rendering Techniques 2000: 11th Eurographics Workshop on Rendering
, 2000
"... The photon map method allows efficient computation of global illumination in general scenes. Individual photon hits, generated using Monte Carlo particle tracing, are stored in the maps and form a geometry independent representation of the illumination. Two important issues with the photon map ar ..."
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Cited by 22 (0 self)
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The photon map method allows efficient computation of global illumination in general scenes. Individual photon hits, generated using Monte Carlo particle tracing, are stored in the maps and form a geometry independent representation of the illumination. Two important issues with the photon map are memory requirements to store the photons and the question how many photons are needed for an accurate representation of illumination in a certain scene. In this paper we introduce a method to control the density of photon maps by storing photons selectively based on a local required density criterion. This reduces memory usage significantly since in unimportant or overdense regions less photons are stored. Results for caustic photon maps and global photon maps representing full illumination show a decrease in number of photons of a factor of 2 to 5. The required density states how accurate the photon map should be at a certain location and determines how many photons are needed in total. We also derive such a criterion based on a novel pathimportancebased first pass, taking some steps towards solving the difficult 'how many photons' question.
Interactive ScreenSpace Accurate Photon Tracing on GPUs
 EUROGRAPHICS SYMPOSIUM ON RENDERING, TOMAS AKENINEMÖLLER AND WOLFGANG HEIDRICH (EDITORS)
, 2006
"... Recent advances in algorithms and graphics hardware have opened the possibility to render caustics at interactive rates on commodity PCs. This paper extends on this work in that it presents a new method to directly render caustics on complex objects, to compute one or several refractions at such obj ..."
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Cited by 21 (2 self)
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Recent advances in algorithms and graphics hardware have opened the possibility to render caustics at interactive rates on commodity PCs. This paper extends on this work in that it presents a new method to directly render caustics on complex objects, to compute one or several refractions at such objects and to simulate caustics shadowing. At the core of our method is the idea to avoid the construction of photon maps by tracing photons in screenspace on programmable graphics hardware. Our algorithm is based on the rasterization of photon paths into texture maps. Intersection events are then resolved on a perfragment basis using layered depth images. To correctly spread photon energy in screenspace we render aligned point sprites at the diffuse receivers where photons terminate. As our method does neither require any preprocessing nor an intermediate radiance representation it can efficiently deal with dynamic scenery and scenery that is modified, or even created on the GPU.
MonteCarlo Methods In Global Illumination
, 2000
"... lightsources, such as point or directional lightsources are preferred here, since their radiance is a Diracdelta like function, which simplifies the integral of equation (2.50) to a sum. These methods take into account only a single reflection of the light coming from the abstract lightsources. Ide ..."
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Cited by 12 (7 self)
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lightsources, such as point or directional lightsources are preferred here, since their radiance is a Diracdelta like function, which simplifies the integral of equation (2.50) to a sum. These methods take into account only a single reflection of the light coming from the abstract lightsources. Ideal mirrors and refracting objects cannot be rendered with these methods. 2. Recursive raytracing Another alternative is to eliminate from the rendering equation those energy contributions which cause the difficulties, and thus give ourselves a simpler problem to solve. For example, if limited level, say n, coupling caused by ideal reflection and refraction were allowed, and we were to ignore the other nonideal components coming from nonabstract lightsources, then the number of surface points which would need to be evaluated to calculate a pixel color can be kept under control. Since the illumination formula contains two terms regarding the coherent components (reflective and refracting l...
Into the blue: Better caustics through photon relaxation
 Eurographics 2009, Computer Graphics Forum
, 2009
"... Abstract The photon mapping method is one of the most popular algorithms employed in computer graphics today. However, obtaining good results is dependent on several variables including kernel shape and bandwidth, as well as the properties of the initial photon distribution. While the photon densit ..."
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Cited by 10 (1 self)
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Abstract The photon mapping method is one of the most popular algorithms employed in computer graphics today. However, obtaining good results is dependent on several variables including kernel shape and bandwidth, as well as the properties of the initial photon distribution. While the photon density estimation problem has been the target of extensive research, most algorithms focus on new methods of optimising the kernel to minimise noise and bias. In this paper we break from convention and propose a new approach that directly redistributes the underlying photons. We show that by relaxing the initial distribution into one with a blue noise spectral signature we can dramatically reduce background noise, particularly in areas of uniform illumination. In addition, we propose an efficient heuristic to detect and preserve features and discontinuities. We then go on to demonstrate how reconfiguration also permits the use of very low bandwidth kernels, greatly improving render times whilst reducing bias.
Sonel mapping: A stochastic acoustical modeling system
 Proceedings of the IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP) 2006
, 2007
"... Modeling the acoustics of an environment is a complex and challenging task. Here we describe the sonel mapping approach to acoustical rendering. Sonel mapping is a MonteCarlobased approach to modeling diffuse, specular, absorption and diffraction effects in an efficient manner. The approach mode ..."
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Cited by 6 (4 self)
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Modeling the acoustics of an environment is a complex and challenging task. Here we describe the sonel mapping approach to acoustical rendering. Sonel mapping is a MonteCarlobased approach to modeling diffuse, specular, absorption and diffraction effects in an efficient manner. The approach models many of the subtle interaction effects required for realistic acoustical modeling, and the approach is computationally efficient allowing it to be used to acoustically model interactive virtual environments. 1.
Photorealistic Image Synthesis Using RayBundles
, 2000
"... lightsources, such as point or directional lightsources are preferred here, since their radiance is a Diracdelta like function, which simplifies the integral of equation (2.50) to a sum. These methods take into account only a single reflection of the light coming from the abstract lightsources. Ide ..."
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Cited by 6 (4 self)
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lightsources, such as point or directional lightsources are preferred here, since their radiance is a Diracdelta like function, which simplifies the integral of equation (2.50) to a sum. These methods take into account only a single reflection of the light coming from the abstract lightsources. Ideal mirrors and refracting objects cannot be rendered with these methods. 2. Recursive raytracing Another alternative is to eliminate from the rendering equation those energy contributions which cause the difficulties, and thus give ourselves a simpler problem to solve. For example, if limited level, say n, coupling caused by ideal reflection and refraction were allowed, and we were to ignore the other nonideal components coming from nonabstract lightsources, then the number of surface points which would need to be evaluated to calculate a pixel color can be kept under control. Since the illumination formula contains two terms regarding the coherent components (reflective and refracting l...
A Rendering Equation for Specular Transfers and Its Integration into Global Illumination
, 1997
"... In this paper, we presenta rigoroustheoretical formulation of the fundamental problemindirectillumination from area sources via curved ideal specular surfaces. Intensity and area factors are introduced to clarify this problem and to rectify the radiance from these specular surfaces. They take sur ..."
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Cited by 6 (5 self)
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In this paper, we presenta rigoroustheoretical formulation of the fundamental problemindirectillumination from area sources via curved ideal specular surfaces. Intensity and area factors are introduced to clarify this problem and to rectify the radiance from these specular surfaces. They take surface geometry, such as Gaussian curvature, into account. Based on this formulation, an algorithm for integrating ideal specular transfers into global illumination is also presented. This algorithm can deal with curved specular reflectorsand transmitters. An implementation is described based on wavefront tracing and progressive radiosity. Sample images generated by this method are presented. Keywords:Rendering equation; Global illumination; Specular transfer; Wavefront tracing; Radiosity; Ray tracing; Meshing 1. Introduction Computing solutions to the global illumination problem is an essential part of photorealistic image synthesis. Global illumination effects produced by multiple surface ...