Volumetric ambient occlusion for volumetric models

Ruiz, M.; Szirmay‐Kalos, László; Umenhoffer, Tamás; Boada, Imma; Feixas, Miquel; Sbert, Mateu

doi:10.1007/s00371-010-0497-z

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…The technique aims at physical representation of diffuse illumination. Ambient occlusion, which is a simplified version of the obscurances, provides more control of the appearance and has been widely used in recent years (e.g., [26][27][28]). Diffuse illumination has also been considered in cartography and GIS.…”

Section: Relief Shadingmentioning

confidence: 99%

Sky-View Factor as a Relief Visualization Technique

2011

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Abstract:Remote sensing has become the most important data source for the digital elevation model (DEM) generation. DEM analyses can be applied in various fields and many of them require appropriate DEM visualization support. Analytical hill-shading is the most frequently used relief visualization technique. Although widely accepted, this method has two major drawbacks: identifying details in deep shades and inability to properly represent linear features lying parallel to the light beam. Several authors have tried to overcome these limitations by changing the position of the light source or by filtering. This paper proposes a new relief visualization technique based on diffuse, rather than direct, illumination. It utilizes the sky-view factor-a parameter corresponding to the portion of visible sky limited by relief. Sky-view factor can be used as a general relief visualization technique to show relief characteristics. In particular, we show that this visualization is a very useful tool in archaeology as it improves the recognition of small scale features from high resolution DEMs.

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Section: Relief Shadingmentioning

confidence: 99%

Sky-View Factor as a Relief Visualization Technique

2011

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“…While some approaches simplify AO to count the number of blockers, horizon‐based AO [BS08], finds the horizon line, that allows to compute a more accurate occlusion. Volumetric approaches use a slightly different definition of AO, where occlusion is the ratio of blocked and unblocked volume in a sphere around a sample [LS10, PMP10, SKUT*10, RSKU*10]. Doing so achieves a more stable result which is less prone to several screen‐space artefacts.…”

Section: Phenomenamentioning

confidence: 99%

The State of the Art in Interactive Global Illumination

Ritschel

Dachsbacher

Grosch³

et al. 2012

Computer Graphics Forum

133

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The interaction of light and matter in the world surrounding us is of striking complexity and beauty. Since the very beginning of computer graphics, adequate modelling of these processes and efficient computation is an intensively studied research topic and still not a solved problem. The inherent complexity stems from the underlying physical processes as well as the global nature of the interactions that let light travel within a scene. This paper reviews the state of the art in interactive global illumination (GI) computation, i.e., methods that generate an image of a virtual scene in less than 1 s with an as exact as possible, or plausible, solution to the light transport. Additionally, the theoretical background and attempts to classify the broad field of methods are described. The strengths and weaknesses of different approaches, when applied to the different visual phenomena, arising from light interaction are compared and discussed. Finally, the paper concludes by highlighting design patterns for interactive GI and a list of open problems.

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“…Due to their simplicity and speed, they are still widely used in practice today, despite having undergone many upgrades. However, their simplicity is also the reason why they are mostly inadequate for more advanced visualizations, as they do not enable a good perception of the depths and shapes of individual structures in the data due to the lack of global illumination or its approximations such as volumetric ambient occlusion [41].…”

Section: Related Workmentioning

confidence: 99%

Combined volume and surface rendering with global illumination caching

et al. 2023

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We present a combined volume and surface rendering technique with global illumination caching. Our approach uses volumetric path tracing to compute the global illumination volume and local shading models for rendering the isosurface. By joining both visualization approaches, we have enhanced the display and illumination of the surfaces while preserving physically realistic illumination of the participating media. To achieve real-time performance and avoid recomputing the image when the camera view changes, we compute the global illumination volume incrementally and defer the projection to a later step. We evaluated our technique by comparing different local shading models for isosurface rendering with the result of full volumetric path tracing and with the non-caching variant of our technique. Results show that the caching and non-caching variants perform comparably well, while the caching variant has the added benefit of being camera-view-independent. Additionally, we show that our approach emphasizes the surfaces within volumes better than volumetric path tracing.

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Volumetric ambient occlusion for volumetric models

Cited by 8 publications

References 9 publications

Sky-View Factor as a Relief Visualization Technique

Sky-View Factor as a Relief Visualization Technique

The State of the Art in Interactive Global Illumination

Combined volume and surface rendering with global illumination caching

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