Curvature depended local illumination approximation of ambient occlusion

Hattori, Tomohito; Kubo, Hiroyuki; Morishima, Shigeo

doi:10.1145/1836845.1836976

Cited by 4 publications

(5 citation statements)

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“…This is an important update from "Curvature depended local illumination approximation of ambient occlusion" (Hattori et al, 2010). In the paper, we have to adopt some look-up table(LUT) or quite rough approximated function which ignore physical property to implement equation(8).…”

Section: Approximation Of Occlusionmentioning

confidence: 99%

Curvature-Approximated Estimation of Real-Time Ambient Occlusion

Hattori¹,

Kubo²,

Morishima³

2012

Proceedings of the International Conference on Computer Graphics Theory and Applications

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We present a novel technique for computing ambient occlusion (Akenine-Möller et al., 2008) on real-time graphics hardware. Our method approximates the occlusion for a local illumination model by introducing curvature-dependent function. Using our method, we are able to acquire occlusion at lower computational cost than conventional methods such as SSAO (Bavoil et al., 2008). Our method requires a multi-pass algorithm with the graphics processing unit (GPU). In the first pass curvature is acquired, and in the second pass the occlusion is computed from the curvature. In the calculating occlusion from the curvature, we approximate the geometric shape by a quadric surface function, and then obtain a curvature dependent function which is an approximation of geometric surface. This function depends only on local variables and we are able to calculate the ambient occlusion for the local illumination model. According to our results, both the computational and storage costs are sufficiently low for the technique to be applied to current graphics hardware supported computer games.

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Section: Approximation Of Occlusionmentioning

confidence: 99%

Curvature-Approximated Estimation of Real-Time Ambient Occlusion

Hattori¹,

Kubo²,

Morishima³

2012

Proceedings of the International Conference on Computer Graphics Theory and Applications

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show abstract

“…Building on Hattori et al [2010], we take a different approach for computing AO on deforming meshes. Using normal curvature, a surface can be approximated with a quadric at each discrete point (Equation 6).…”

Section: Ambient Occlusionmentioning

confidence: 99%

“…Like Hattori et al [2010], we pre-compute ambient occlusion using Equation 11 for values of curvature where the quadric is concave in both directions. We then create a lookup texture indexed by minimum and maximum principal curvatures that can be used directly in a pixel shader.…”

Section: Approximating Ambient Occlusionmentioning

confidence: 99%

“…Hattori et al [2010] use a quadric surface approximation to analytically solve for ambient occlusion. The quadric approximation requires estimated curvature.…”

mentioning

confidence: 99%

“…To demonstrate our algorithm, we implement an ambient occlusion approximation based on Hattori et al [2010], a vertex-blending animation system [Akenine-Möller et al 2008] and a GPU-based isosurface computation system. The specific contributions of this paper are:…”

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confidence: 99%

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GPU curvature estimation on deformable meshes

Griffin

Wang

Berrios

et al. 2011

Symposium on Interactive 3D Graphics and Games

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Figure 1: On the left is one frame of an elephant animation visualizing estimated curvature. Blue indicates concave areas, red indicates convex areas, and green indicates saddle-shape areas. The middle is using surface curvature to approximate ambient occlusion. On the right is an orange volume with ∼1.5 billion vertices with Lambertian shading and ambient occlusion which we estimate curvature on in 39.3 ms. AbstractSurface curvature is used in a number of areas in computer graphics, including texture synthesis and shape representation, mesh simplification, surface modeling, and non-photorealistic line drawing. Most real-time applications must estimate curvature on a triangular mesh. This estimation has been limited to CPU algorithms, forcing object geometry to reside in main memory. However, as more computational work is done directly on the GPU, it is increasingly common for object geometry to exist only in GPU memory. Examples include vertex skinned animations and isosurfaces from GPU-based surface reconstruction algorithms.For static models, curvature can be pre-computed and CPU algorithms are a reasonable choice. For deforming models where the geometry only resides on the GPU, transferring the deformed mesh back to the CPU limits performance. We introduce a GPU algorithm for estimating curvature in real-time on arbitrary triangular meshes. We demonstrate our algorithm with curvature-based NPR feature lines and a curvature-based approximation for ambient occlusion. We show curvature computation on volumetric datasets with a GPU isosurface extraction algorithm and vertex-skinned animations. Our curvature estimation is up to ∼18x faster than a multithreaded CPU benchmark.

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Real-Time GPU Surface Curvature Estimation on Deforming Meshes and Volumetric Data Sets

Griffin

Wang

Berrios

et al. 2012

IEEE Trans. Visual. Comput. Graphics

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Surface curvature is used in a number of areas in computer graphics, including texture synthesis and shape representation, mesh simplification, surface modeling, and nonphotorealistic line drawing. Most real-time applications must estimate curvature on a triangular mesh. This estimation has been limited to CPU algorithms, forcing object geometry to reside in main memory. However, as more computational work is done directly on the GPU, it is increasingly common for object geometry to exist only in GPU memory. Examples include vertex skinned animations and isosurfaces from GPU-based surface reconstruction algorithms. For static models, curvature can be precomputed and CPU algorithms are a reasonable choice. For deforming models where the geometry only resides on the GPU, transferring the deformed mesh back to the CPU limits performance. We introduce a GPU algorithm for estimating curvature in real time on arbitrary triangular meshes. We demonstrate our algorithm with curvature-based NPR feature lines and a curvature-based approximation for an ambient occlusion. We show curvature computation on volumetric data sets with a GPU isosurface extraction algorithm and vertex-skinned animations. We present a graphics pipeline and CUDA implementation. Our curvature estimation is up to ~18x faster than a multithreaded CPU benchmark.

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Curvature depended local illumination approximation of ambient occlusion

Cited by 4 publications

References 1 publication

Curvature-Approximated Estimation of Real-Time Ambient Occlusion

Curvature-Approximated Estimation of Real-Time Ambient Occlusion

GPU curvature estimation on deformable meshes

Real-Time GPU Surface Curvature Estimation on Deforming Meshes and Volumetric Data Sets

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