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All-frequency shadows using non-linear wavelet lighting approximation

Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
2003 ACM Transactions on Graphics  
For accurate rendering, using non-linear wavelets is an order of magnitude faster than using linear spherical harmonics, the current best technique.  ...  Our main contribution is to approximate the environment map in a wavelet basis, keeping only the largest terms (this is known as a non-linear approximation).  ...  Acknowledgments We would like to thank Henrik Wann Jensen for helping compute transport matrices and for discussions; Paul Debevec for the lighting environments (http://www.debevec.org/probes/); Mike Houston  ... 
doi:10.1145/882262.882280 fatcat:td7n6zwl2rg5zlsd5pdtqf3isy

All-frequency shadows using non-linear wavelet lighting approximation

Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
2003 ACM SIGGRAPH 2003 Papers on - SIGGRAPH '03  
For accurate rendering, using non-linear wavelets is an order of magnitude faster than using linear spherical harmonics, the current best technique.  ...  Our main contribution is to approximate the environment map in a wavelet basis, keeping only the largest terms (this is known as a non-linear approximation).  ...  Acknowledgments We would like to thank Henrik Wann Jensen for helping compute transport matrices and for discussions; Paul Debevec for the lighting environments (http://www.debevec.org/probes/); Mike Houston  ... 
doi:10.1145/1201775.882280 fatcat:onagab3hnfgmffpnh3xrybcxlu

All-Frequency Relighting of Non-Diffuse Objects using Separable BRDF Approximation [article]

Rui Wang, John Tran, David Luebke
2004 Symposium on Rendering  
Non-linear wavelet lighting approximation is able to capture all-frequency illumination and shadows for geometry relighting, but interactive rendering is currently limited to diffuse objects.  ...  We then pre-compute light transport matrices corresponding to each BRDF light map, and compress the data with a non-linear wavelet approximation.  ...  Acknowledgements The models used are courtesy of the Stanford 3D Scanning Repository. We would like to thank Nolan Goodnight for advice on our work.  ... 
doi:10.2312/egwr/egsr04/345-354 fatcat:ywwmm6h6erfkvjqz5udkw2n4ge

4D compression and relighting with high-resolution light transport matrices

Ewen Cheslack-Postava, Nolan Goodnight, Ren Ng, Ravi Ramamoorthi, Greg Humphreys
2007 Proceedings of the 2007 symposium on Interactive 3D graphics and games - I3D '07  
We show that a standard 4D wavelet transform can actually inflate portions of the matrix, because highfrequency lights lead to high-frequency images that cannot easily be compressed.  ...  We accomplish this using a 4D wavelet transform, transforming the columns of the transport matrix, in addition to the 2D row transform used in previous work.  ...  The running time for this relighting algorithm is linear in the number of lights used for the non-linear approximation.  ... 
doi:10.1145/1230100.1230115 dblp:conf/si3d/Cheslack-PostavaGNRH07 fatcat:ez3xd23t7zdnjhwjam4w4sqe4i

All-frequency relighting of glossy objects

Rui Wang, John Tran, David Luebke
2006 ACM Transactions on Graphics  
We use modern graphics hardware to accelerate this step, and further compress the data using a non-linear wavelet approximation.  ...  We present a technique for interactive rendering of glossy objects in complex and dynamic lighting environments that captures interreflections and all-frequency shadows.  ...  The models used in this paper are courtesy of the Stanford University Computer Graphics Laboratory.  ... 
doi:10.1145/1138450.1138456 fatcat:f3z65guzf5f2nc4brrvsqfate4

Exploiting Temporal Coherence for Incremental All-Frequency Relighting [article]

Ryan Overbeck, Aner Ben-Artzi, Ravi Ramamoorthi, Eitan Grinspun
2006 Symposium on Rendering  
Precomputed radiance transfer (PRT) enables all-frequency relighting with complex illumination, materials and shadows.  ...  Exploiting temporal coherence of dynamic lighting yields a 3×-4× performance improvement, e.g., all-frequency effects are achieved with 30 wavelet coefficients per frame for the lighting, about the same  ...  We thank Ren Ng for making available his code frameworks and scenes for all-frequency relighting.  ... 
doi:10.2312/egwr/egsr06/151-160 fatcat:2apxsxap6bggxm6rvyhhlx3ata

Smooth Reconstruction and Compact Representation of Reflectance Functions for Image-based Relighting [article]

Vincent Masselus, Pieter Peers, Philip Dutré, Yves D. Willemsy
2004 Symposium on Rendering  
We use a non-linear approximation of higher order wavelets to preserve the smoothness of the reconstructed signal while maintaining good relit image quality.  ...  The presented method maintains important high frequency features such as highlights and self-shadowing and ensures visually pleasing relit images, computed with incident illumination containing high and  ...  We propose to use a non-linear approximation of the reflectance functions using higher order wavelets for this set of common basis functions.  ... 
doi:10.2312/egwr/egsr04/287-298 fatcat:4r3xjd3sr5g37o5glotm6j3mue

Triple product wavelet integrals for all-frequency relighting

Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
2004 ACM SIGGRAPH 2004 Papers on - SIGGRAPH '04  
We then give efficient linear and sublinear-time algorithms for Haar wavelets, incorporating non-linear wavelet approximation of lighting and BRDFs.  ...  This paper focuses on efficient rendering based on pre-computed light transport, with realistic materials and shadows under allfrequency direct lighting such as environment maps.  ...  Moser for allowing us to copy the likeness of their Continuous Arm Chair.  ... 
doi:10.1145/1186562.1015749 fatcat:t4dgu5dlznf5xceheswyzw2sci

Triple product wavelet integrals for all-frequency relighting

Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
2004 ACM Transactions on Graphics  
We then give efficient linear and sublinear-time algorithms for Haar wavelets, incorporating non-linear wavelet approximation of lighting and BRDFs.  ...  This paper focuses on efficient rendering based on pre-computed light transport, with realistic materials and shadows under allfrequency direct lighting such as environment maps.  ...  Moser for allowing us to copy the likeness of their Continuous Arm Chair.  ... 
doi:10.1145/1015706.1015749 fatcat:4a4hd4lylbgiff3liygl4urvpa

Rendering of Translucent Objects Based upon PRT

Jin Zhou, Zhang Jiawan, Sun Jizhou
2007 Fourth International Conference on Image and Graphics (ICIG 2007)  
First, the complete BSSRDF model is considered and the two-pass hierarchical technique by [5] in the space of non-linearly approximated transport vectors is applied, which efficiently evaluate transport  ...  Single scattering is also incorporated by considering [16]'s approximation.  ...  And we choose a subset of wavelet basis lights to use for the current frame for non-linear approximation.  ... 
doi:10.1109/icig.2007.87 fatcat:ak6e62sku5f6bhtenhveqtzl6y

Sparse representation of cast shadows via ℓ1-regularized least squares

Xue Mei, Haibin Ling, David W Jacobs
2009 2009 IEEE 12th International Conference on Computer Vision  
Scenes with cast shadows can produce complex sets of images. These images cannot be well approximated by lowdimensional linear subspaces.  ...  However, in this paper we show that the set of images produced by a Lambertian scene with cast shadows can be efficiently represented by a sparse set of images generated by directional light sources.  ...  absence of cast shadows, this lighting can be approximated using low frequency spherical harmonics [2, 21] .  ... 
doi:10.1109/iccv.2009.5459185 dblp:conf/iccv/MeiLJ09 fatcat:cq5gqdpienbjxihvzfli3fpqpm

Generalized wavelet product integral for rendering dynamic glossy objects

Weifeng Sun, Amar Mukherjee
2006 ACM SIGGRAPH 2006 Papers on - SIGGRAPH '06  
We consider real-time rendering of dynamic glossy objects with realistic shadows under distant all-frequency environment lighting.  ...  We demonstrate JRT technique in the interactive lighting design system to provide realistic all-frequency shadows in real-time.  ...  A natural approach to accelerating computation is to apply non-linear approximation to all operand functions. For this purpose, we use the augmented quadtree as the underlying data structure.  ... 
doi:10.1145/1179352.1141980 fatcat:vpjiv4cnprevlpd26eekeym5bq

Generalized wavelet product integral for rendering dynamic glossy objects

Weifeng Sun, Amar Mukherjee
2006 ACM Transactions on Graphics  
We consider real-time rendering of dynamic glossy objects with realistic shadows under distant all-frequency environment lighting.  ...  We demonstrate JRT technique in the interactive lighting design system to provide realistic all-frequency shadows in real-time.  ...  A natural approach to accelerating computation is to apply non-linear approximation to all operand functions. For this purpose, we use the augmented quadtree as the underlying data structure.  ... 
doi:10.1145/1141911.1141980 fatcat:tis47scm5vdspbox4vbt3cvux4

Precomputation-Based Rendering

Ravi Ramamoorthi
2007 Foundations and Trends in Computer Graphics and Vision  
In these cases, the final image or rendering is a linear combination of basis images or radiance distributions due to individual lights.  ...  Complex lighting, reflection, shadow and global illumination effects can be rendered with modern image synthesis algorithms, but those methods are focused on offline computation of a single image.  ...  My first PRT papers were in collaboration with Ren Ng, who coined the term "all-frequency" and provided the main motivation towards reaching that goal.  ... 
doi:10.1561/0600000021 fatcat:lruiwpvi75bevf5ietum5cn33q

Efficient Wavelet Rotation for Environment Map Rendering [article]

Rui Wang, Ren Ng, David Luebke, Greg Humphreys
2006 Symposium on Rendering  
We show that using these matrices allows us to evaluate the integral of dynamic lighting with dynamic BRDFs at interactive rates, incorporating efficient non-linear approximation of both illumination and  ...  Wavelets are superior at approximating high frequency signals such as detailed high dynamic range lighting and very shiny BRDFs, but present difficulties for interactive rendering due to the lack of an  ...  The primary error in the rotated lighting comes from the non-linear wavelet approximation of the source lighting.  ... 
doi:10.2312/egwr/egsr06/173-182 fatcat:t7tr73ahuzd2vhc7ekfbsecxpa
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