Concentric Spherical Representation for Omnidirectional Soft Shadow

Xiao, Yi; Leung, Chi-Sing; Ho, Tze Yui; Wan, Liang; Wong, Tien Tsing

doi:10.1111/cgf.12085

Cited by 6 publications

(4 citation statements)

References 29 publications

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“…In omnidirectional soft shadow generation, we use directly the omnidirectional form of CSS [XLH∗ 13] mentioned in Section 2.2. The soft shadow generation follows the flowchart Fig.…”

Section: Methodsmentioning

confidence: 99%

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Seamless Mipmap Filtering for Dual Paraboloid Maps

Wang

Leung

et al. 2019

Computer Graphics Forum

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Dual paraboloid mapping is an approach for environment mapping. Its major advantage is its fast map generation speed. For graphics applications, when filtering is needed, the filtering tool would naturally be mipmapping. However, directly applying mipmapping to dual paraboloid mapping would give us three problems. They are the discontinuity across the dual paraboloid map boundary, the non‐uniform sampling problem and the depth testing issue. We propose three approaches to solve these problems. Our approaches are based on some closed form equations derived via theoretical analysis. Using these equations, we modify the coordinates involved during the rendering process. In other words, these problems are handled just by using dual paraboloid maps and mipmaps differently, instead of fundamentally altering their data structures. Consequently, we are fixing the problems without damaging the map generation speed advantage. Applying all three approaches, we improve the rendering quality of dual paraboloid map mipmaps to a level equivalent to that of cubemap mipmaps, while preserving its fast map generation speed advantage. This gives dual paraboloid map mipmaps the potential to be a better choice than cubemap mipmaps for the devices with less computational power. The effectiveness and the efficiency of the proposed approaches are demonstrated using a glossy reflection application and an omnidirectional soft shadow generation application.

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“…In omnidirectional soft shadow generation, we use directly the omnidirectional form of CSS [XLH∗ 13] mentioned in Section 2.2. The soft shadow generation follows the flowchart Fig.…”

Section: Methodsmentioning

confidence: 99%

“…CSM and CSM‐Z) for the average blocker depth and the soft shadow factors. [XLH∗ 13] extends CSS from planar light sources to omnidirectional light sources. Compared with CSS, its major difference is that it uses the environment mapping tools (e.g.…”

Section: Introductionmentioning

confidence: 99%

Seamless Mipmap Filtering for Dual Paraboloid Maps

Wang

Leung

et al. 2019

Computer Graphics Forum

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“…Based on convolution shadow maps [24], convolution soft shadows (CSS) [25] can work with animated models and render distal direct illumination with all frequency soft shadows. It is later extended to omnidirectional scenarios [26,27] to handle local light sources.…”

Section: Prt Algorithmsmentioning

confidence: 99%

Temporal vectorized visibility for direct illumination of animated models

Wang,

Ho,

Xiao

et al. 2024

Comp. Visual Media

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Direct illumination rendering is an important technique in computer graphics. Precomputed radiance transfer algorithms can provide high quality rendering results in real time, but they can only support rigid models. On the other hand, ray tracing algorithms are flexible and can gracefully handle animated models. With NVIDIA RTX and the AI denoiser, we can use ray tracing algorithms to render visually appealing results in real time. Visually appealing though, they can deviate from the actual one considerably. We propose a visibility-boundary edge oriented infinite triangle bounding volume hierarchy (BVH) traversal algorithm to dynamically generate visibility in vector form. Our algorithm utilizes the properties of visibility-boundary edges and infinite triangle BVH traversal to maximize the efficiency of the vector form visibility generation. A novel data structure, temporal vectorized visibility, is proposed, which allows visibility in vector form to be shared across time and further increases the generation efficiency. Our algorithm can efficiently render close-to-reference direct illumination results. With the similar processing time, it provides a visual quality improvement around 10 dB in terms of peak signal-to-noise ratio (PSNR) w.r.t. the ray tracing algorithm reservoir-based spatiotemporal importance resampling (ReSTIR).

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“…Based on above observation, Shor et al [7] applied the illumination transfer approach [8] for shadow removal. The lit intensity at x can be expressed as an affine function between the illuminated and shadowed intensities :…”

Section: Paired Regions and Shadow Removalmentioning

confidence: 99%

Image Shadow Removal Using Paired Region Illumination Transfer

Chen

Yang

Jin

2015

AMM

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In this paper we present a novel method for shadow detection and removal in single images. Instead of a single Gaussian distribution in the shadow detection stage, it is assumed as a Gaussian Mixture Shadow Model (GMSM) which parameters are estimated by model learning. In addition to considering individual regions separately, we predict relative illumination conditions between the shadow regions and non-shadow regions. The shadow image is recovered by relighting each pixel based on our paired lighting model. The experiment results confirm the effectiveness of our proposed method.

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Concentric Spherical Representation for Omnidirectional Soft Shadow

Cited by 6 publications

References 29 publications

Seamless Mipmap Filtering for Dual Paraboloid Maps

Seamless Mipmap Filtering for Dual Paraboloid Maps

Temporal vectorized visibility for direct illumination of animated models

Image Shadow Removal Using Paired Region Illumination Transfer

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