{"title":"Perceptually based tone mapping of high dynamic range image streams","authors":"P. Irawan, J. Ferwerda, Steve Marschner","doi":"10.2312/EGWR/EGSR05/231-242","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/231-242","url":null,"abstract":"This paper presents a new perceptually based tone mapping operator that represents scene visibility under timevarying, high dynamic range conditions. The operator is based on a new generalized threshold model that extends the conventional threshold-versus-intensity (TVI) function to account for the viewer's adaptation state, and a new temporal adaptation model that includes fast and slow neural mechanisms as well as photopigment bleaching. These new visual models allow the operator to produce tone-mapped image streams that represent the loss of visibility experienced under changing illumination conditions and in high dynamic range scenes. By varying the psychophysical data that the models use, we simulate the differences in scene visibility experienced by normal and visually impaired observers.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"450 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134435293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inferring reflectance functions from wavelet noise","authors":"Pieter Peers, P. Dutré","doi":"10.2312/EGWR/EGSR05/173-182","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/173-182","url":null,"abstract":"This paper presents a novel method for acquiring a wavelet representation of the reflectance field of real objects. Key to our method is the use of wavelet noise illumination to infer a reflectance function for each pixel. Due to their stochastic nature, these wavelet noise patterns enable to trade off the number of recorded photographs for the quality of the computed reflectance functions. Additionally, each wavelet noise pattern affects all pixels in a recorded photograph, independently of the underlying material properties in the scene. Consequently, each recorded photograph contributes additional information to the reflectance field computation.\u0000 The presented method consists of three steps. First, a fixed number of photographs are recorded of the scene lit by a series of wavelet noise patterns emitted from a CRT monitor. Next, for each pixel a reflectance function is computed offline, by identifying the important wavelet coefficients for the pixel's reflectance function. The coefficients are computed by solving a linear least squares problem. Finally, once all reflectance functions are computed, a novel image of the scene can be composited with arbitrary incident illumination.\u0000 The method can be used for both image-based relighting and environment matting.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134560012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spherical Q2-tree for sampling dynamic environment sequences","authors":"Liang Wan, T. Wong, A. Leung","doi":"10.2312/EGWR/EGSR05/021-030","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/021-030","url":null,"abstract":"Previous methods in environment map sampling seldom consider a sequence of dynamic environment maps. The generated sampling patterns of the sequence may not maintain the temporal illumination consistency and result in choppy animation. In this paper, we propose a novel approach, spherical Q2-tree, to address this consistency problem. The local adaptive nature of the proposed method suppresses the abrupt change in the generated sampling patterns over time, hence ensures a smooth and consistent illumination. By partitioning the spherical surface with simple curvilinear equations, we construct a quadrilateral-based quadtree over the sphere. This Q2-tree allows us to adaptively sample the environment based on an importance metric and generates low-discrepancy sampling patterns. No time-consuming relaxation is required. The sampling patterns of a dynamic sequence are rapidly generated by making use of the summed area table and exploiting the coherence of consecutive frames. From our experiments, the rendering quality of our sampling pattern for a static environment map is comparable to previous methods. However, our method produces smooth and consistent animation for a sequence of dynamic environment maps, even the number of samples is kept constant over time.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126499263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Importance resampling for global illumination","authors":"Justin Talbot, David Cline, P. Egbert","doi":"10.2312/EGWR/EGSR05/139-146","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/139-146","url":null,"abstract":"This paper develops importance resampling into a variance reduction technique for Monte Carlo integration. Importance resampling is a sample generation technique that can be used to generate more equally weighted samples for importance sampling. This can lead to significant variance reduction over standard importance sampling for common rendering problems. We show how to select the importance resampling parameters for near optimal variance reduction. We demonstrate the robustness of this technique on common global illumination problems and achieve a 10%-70% variance reduction over standard importance sampling for direct lighting. We conclude that further variance reduction could be achieved with cheaper sampling methods.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122879756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Metropolis photon sampling with optional user guidance","authors":"Shaohua Fan, Stephen Chenney, Yu-Chi Lai","doi":"10.2312/EGWR/EGSR05/127-138","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/127-138","url":null,"abstract":"We present Metropolis Photon Sampling (MPS), a visual importance-driven algorithm for populating photon maps. Photon Mapping and other particle tracing algorithms fail if the photons are poorly distributed. Our approach samples light transport paths that join a light to the eye, which accounts for the viewer in the sampling process and provides information to improve photon storage. Paths are sampled with a Metropolis-Hastings algorithm that exploits coherence among important light paths. We also present a technique for including user selected paths in the sampling process without introducing bias. This allows a user to provide hints about important paths or reduce variance in specific parts of the image. We demonstrate MPS with a range of scenes and show quantitative improvements in error over standard Photon Mapping and Metropolis Light Transport.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"1 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131861786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bayesian relighting","authors":"M. Fuchs, V. Blanz, H. Seidel","doi":"10.2312/EGWR/EGSR05/157-164","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/157-164","url":null,"abstract":"We present a simple method for relighting real objects viewed from a fixed camera position. Instead of setting up a calibrated measurement device, such as a light stage, we manually sweep a spotlight over the walls of a white room, illuminating the object indirectly. In contrast to previous methods, we use arbitrary and unknown angular distributions of incoming light. Neither the incident light nor the reflectance function need to be represented explicitly in our approach.\u0000 The new method relies on images of a probe object, for instance a black snooker ball, placed near the target object. Pictures of the probe in a novel illumination are decomposed into a linear combination of measured images of the probe. Then, a linear combination of images of the target object with the same coefficients produces a synthetic image with the new illumination. We use a simple Bayesian approach to find the most plausible output image, given the picture of the probe and the statistics observed in the dataset of samples.\u0000 Our results for a variety of novel illuminations, including synthetic lighting by relatively narrow light sources as well as natural illuminations, demonstrate that the new technique is a useful, low cost alternative to existing techniques for a broad range of objects and materials.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121048479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adaptive numerical cumulative distribution functions for efficient importance sampling","authors":"Jason Lawrence, S. Rusinkiewicz, R. Ramamoorthi","doi":"10.2312/EGWR/EGSR05/011-020","DOIUrl":"https://doi.org/10.2312/EGWR/EGSR05/011-020","url":null,"abstract":"As image-based surface reflectance and illumination gain wider use in physically-based rendering systems, it is becoming more critical to provide representations that allow sampling light paths according to the distribution of energy in these high-dimensional measured functions. In this paper, we apply algorithms traditionally used for curve approximation to reduce the size of a multidimensional tabulated Cumulative Distribution Function (CDF) by one to three orders of magnitude without compromising its fidelity. These adaptive representations enable new algorithms for sampling environment maps according to the local orientation of the surface and for multiple importance sampling of image-based lighting and measured BRDFs.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126769421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"sLayer: a System for Multi-Layered Material Sculpting","authors":"Claudio Calabrese, M. Fratarcangeli, F. Pellacini","doi":"10.2312/sre.20171199","DOIUrl":"https://doi.org/10.2312/sre.20171199","url":null,"abstract":"Many real world materials have a stratified structure, composed by the proximity and the interaction of multiple highly-detailed layers. Example of these materials are peeling paint, old tree bark and rusted metals. While digital sculpting is particularly well-suited to model these aged surfaces, the interaction between layers is not accounted for. We present a system for sculpting multi-layers materials where collision between layers are handled interactively while brushing meshes that scales up to the million of polygons necessary to model aged surfaces. We do so by observing that if the average mean edge length is maintained constant throughout the modeling session, we can use a single data structure, namely a uniform grid, to accelerate all the sculpting operations.We present a brush rasterization pipeline that uses this data structure for multi-layer editing.We also show that by adding a few interface tools for layer creation and selection, we can create detailed surface similar to real-world ones. To the best of our knowledge, our work is the first to show sculpting of highly-detailed, multi-layered materials in real-time.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127435096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-Scale Appearance Modeling of Granular Materials with Continuously Varying Grain Properties","authors":"Cheng Zhang, Shuang Zhao","doi":"10.2312/sr.20201134","DOIUrl":"https://doi.org/10.2312/sr.20201134","url":null,"abstract":"Many real-world materials such as sand, snow, salt, and rice are comprised of large collections of grains. Previously, multiscale rendering of granular materials requires precomputing light transport per grain and has difficulty in handling materials with continuously varying grain properties. Further, existing methods usually describe granular materials by explicitly storing individual grains, which becomes hugely data-intensive to describe large objects, or replicating small blocks of grains, which lacks the flexibility to describe materials with grains distributed in nonuniform manners. We introduce a new method to render granular materials with continuously varying grain optical properties efficiently. This is achieved using a novel symbolic and differentiable simulation of light transport during precomputation. Additionally, we introduce a new representation to depict large-scale granular materials with complex grain distributions. After constructing a template tile as preprocessing, we adapt it at render time to generate large quantities of grains with user-specified distributions. We demonstrate the effectiveness of our techniques using a few examples with a variety of grain properties and distributions. CCS Concepts • Computing methodologies → Rendering; Ray tracing;","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127534466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Planetary Shadow-Aware Distance Sampling","authors":"Carl Breyer, Tobias Zirr","doi":"10.2312/sr.20221152","DOIUrl":"https://doi.org/10.2312/sr.20221152","url":null,"abstract":"Dusk and dawn scenes have been difficult for brute force path tracers to handle. We identify that a major source of the inefficiency in explicitly path tracing the atmosphere in such conditions stems from wasting samples on the denser lower parts of atmosphere that get shadowed by the planet before the upper, thinner parts when the star sets below the horizon. We present a technique that overcomes this issue by sampling the star only from the unshadowed segments along rays based on boundaries found by intersecting a cylinder fit to the planet’s shadow. We also sample the transmittance by mapping the distances of the boundaries to opacities and sampling the visible segments uniformly in opacity space. Our technique can achieve similar quality compared to brute-force path tracing at around a 60th of the time in such conditions.","PeriodicalId":363391,"journal":{"name":"Eurographics Symposium on Rendering","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126091263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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