EGSR11: 22th Eurographics Symposium on Rendering
https://diglib.eg.org:443/handle/10.2312/390
2024-03-29T11:31:46ZGuided Image Filtering for Interactive High-quality Global Illumination
https://diglib.eg.org:443/handle/10.1111/v30i4pp1361-1368
Guided Image Filtering for Interactive High-quality Global Illumination
Bauszat, Pablo; Eisemann, Martin; Magnor, Marcus
Ravi Ramamoorthi and Erik Reinhard
Interactive computation of global illumination is a major challenge in current computer graphics research. Global illumination heavily affects the visual quality of generated images. It is therefore a key attribute for the perception of photo-realistic images. Path tracing is able to simulate the physical behaviour of light using Monte Carlo techniques. However, the computational burden of this technique prohibits interactive rendering times on standard commodity hardware in high-quality. Trying to solve the Monte Carlo integration with fewer samples results in characteristic noisy images. Global illumination filtering methods take advantage of the fact that the integral for neighbouring pixels may be very similar. Averaging samples of similar characteristics in screen-space may approximate the correct integral, but may result in visible outliers. In this paper, we present a novel path tracing pipeline based on an edge-aware filtering method for the indirect illumination which produces visually more pleasing results without noticeable outliers. The key idea is not to filter the noisy path traced images but to use it as a guidance to filter a second image composed from characteristic scene attributes that do not contain noise by default. We show that our approach better approximates the Monte Carlo integral compared to previous methods. Since the computation is carried out completely in screen-space it is therefore applicable to fully dynamic scenes, arbitrary lighting and allows for high-quality path tracing at interactive frame rates on commodity hardware.
2011-01-01T00:00:00ZCoherent Out-of-Core Point-Based Global Illumination
https://diglib.eg.org:443/handle/10.1111/v30i4pp1353-1360
Coherent Out-of-Core Point-Based Global Illumination
Kontkanen, Janne; Tabellion, Eric; Overbeck, Ryan S.
Ravi Ramamoorthi and Erik Reinhard
We describe a new technique for coherent out-of-core point-based global illumination and ambient occlusion. Point-based global illumination (PBGI) is used in production to render tremendously complex scenes, so in-core storage of point and octree data structures quickly becomes a problem. However, a simple out-of-core extension of a classical top-down octree building algorithm would be extremely inefficient due to large amount of I/O required. Our method extends previous PBGI algorithms with an out-of-core technique that uses minimal I/O and stores data on disk compactly and in coherent chunks for later access during shading. Using properties of a space-filling Z-curve, we are able to preprocess the data in two passes: an external 1D-sort and an octree construction pass.
2011-01-01T00:00:00ZA Ray Tracing Approach to Diffusion Curves
https://diglib.eg.org:443/handle/10.1111/v30i4pp1345-1352
A Ray Tracing Approach to Diffusion Curves
Bowers, John C.; Leahey, Jonathan; Wang, Rui
Ravi Ramamoorthi and Erik Reinhard
Diffusion curves [OBW*08] provide a flexible tool to create smooth-shaded images from curves defined with colors. The resulting image is typically computed by solving a Poisson equation that diffuses the curve colors to the interior of the image. In this paper we present a new method for solving diffusion curves by using ray tracing. Our approach is analogous to final gathering in global illumination, where the curves define source radiance whose visible contribution will be integrated at a shading pixel to produce a color using stochastic ray tracing. Compared to previous work, the main benefit of our method is that it provides artists with extended flexibility in achieving desired image effects. Specifically, we introduce generalized curve colors called shaders that allow for the seamless integration of diffusion curves with classic 2D graphics including vector graphics (e.g. gradient fills) and raster graphics (e.g. patterns and textures). We also introduce several extended curve attributes to customize the contribution of each curve. In addition, our method allows any pixel in the image to be independently evaluated, without having to solve the entire image globally (as required by a Poisson-based approach). Finally, we present a GPU-based implementation that generates solution images at interactive rates, enabling dynamic curve editing. Results show that our method can easily produce a variety of desirable image effects.
2011-01-01T00:00:00ZDirect Ray Tracing of Phong Tessellation
https://diglib.eg.org:443/handle/10.1111/v30i4pp1337-1344
Direct Ray Tracing of Phong Tessellation
Ogaki, Shinji; Tokuyoshi, Yusuke
Ravi Ramamoorthi and Erik Reinhard
There are two major ways of calculating ray and parametric surface intersections in rendering. The first is through the use of tessellated triangles, and the second is to use parametric surfaces together with numerical methods such as Newton's method. Both methods are computationally expensive and complicated to implement. In this paper, we focus on Phong Tessellation and introduce a simple direct ray tracing method for Phong Tessellation. Our method enables rendering smooth surfaces in a computationally inexpensive yet robust way.
2011-01-01T00:00:00Z