Dynamic Scenes (dynamic + scene)

Distribution by Scientific Domains


Selected Abstracts


Generalized minimum-norm perspective shadow maps

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 5 2008
Fan Zhang
Abstract Shadow mapping has been extensively used for real-time shadow rendering in 3D computer games, though it suffers from the inherent aliasing problems due to its image-based nature. This paper presents an enhanced variant of light space perspective shadow maps to optimize perspective aliasing distribution in possible general cases where the light and view directions are not orthogonal. To be mathematically sound, the generalized representation of perspective aliasing errors has been derived in detail. Our experiments have shown the enhanced shadow quality using our algorithm in dynamic scenes. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Video completion and synthesis

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008
Chunxia Xiao
Abstract This paper presents a new exemplar-based framework for video completion, allowing aesthetically pleasing completion of large space-time holes. We regard video completion as a discrete global optimization on a 3D graph embedded in the space-time video volume. We introduce a new objective function which enforces global spatio-temporal consistency among patches that fill the hole and surrounding it, in terms of both color similarity and motion similarity. The optimization is solved by a novel algorithm, called weighted priority belief propagation (BP), which alleviates the problems of slow convergence and intolerable storage size when using the standard BP. This objective function can also handle video texture synthesis by extending an input video texture to a larger texture region. Experiments on a wide variety of video examples with complex dynamic scenes demonstrate the advantages of our method over existing techniques: salient structures and motion information are much better restored. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Hierarchical Image-Space Radiosity for Interactive Global Illumination

COMPUTER GRAPHICS FORUM, Issue 4 2009
Greg Nichols
Abstract We introduce image-space radiosity and a hierarchical variant as a method for interactively approximating diffuse indirect illumination in fully dynamic scenes. As oft observed, diffuse indirect illumination contains mainly low-frequency details that do not require independent computations at every pixel. Prior work leverages this to reduce computation costs by clustering and caching samples in world or object space. This often involves scene preprocessing, complex data structures for caching, or wasted computations outside the view frustum. We instead propose clustering computations in image space, allowing the use of cheap hardware mipmapping and implicit quadtrees to allow coarser illumination computations. We build on a recently introduced multiresolution splatting technique combined with an image-space lightcut algorithm to intelligently choose virtual point lights for an interactive, one-bounce instant radiosity solution. Intelligently selecting point lights from our reflective shadow map enables temporally coherent illumination similar to results using more than 4096 regularly-sampled VPLs. [source]


Occlusion Textures for Plausible Soft Shadows,

COMPUTER GRAPHICS FORUM, Issue 1 2008
E. Eisemann
Abstract This paper presents a new approach to compute plausible soft shadows for complex dynamic scenes and rectangular light sources. We estimate the occlusion at each point of the scene using prefiltered occlusion textures, which dynamically approximate the scene geometry. The algorithm is fast and its performance independent of the light's size. Being image-based, it is mostly independent of the scene complexity and type. No a priori information is needed, and there is no caster/receiver separation. This makes the method appealing and easy to use. [source]


High-Quality Adaptive Soft Shadow Mapping

COMPUTER GRAPHICS FORUM, Issue 3 2007
GaŽl Guennebaud
Abstract The recent soft shadow mapping technique [GBP06] allows the rendering in real-time of convincing soft shadows on complex and dynamic scenes using a single shadow map. While attractive, this method suffers from shadow overestimation and becomes both expensive and approximate when dealing with large penumbrae. This paper proposes new solutions removing these limitations and hence providing an efficient and practical technique for soft shadow generation. First, we propose a new visibility computation procedure based on the detection of occluder contours, that is more accurate and faster while reducing aliasing. Secondly, we present a shadow map multi-resolution strategy keeping the computation complexity almost independent on the light size while maintaining high-quality rendering. Finally, we propose a view-dependent adaptive strategy, that automatically reduces the screen resolution in the region of large penumbrae, thus allowing us to keep very high frame rates in any situation. [source]


Perceiving patterns in dynamic action sequences: Investigating the processes underpinning stimulus recognition and anticipation skill

APPLIED COGNITIVE PSYCHOLOGY, Issue 6 2009
Jamie S. North
We examined whether skilled and less-skilled participants process dynamic sequences comprised of numerous elements using relational information or specific display features. Moreover, the processes underpinning anticipation and recognition judgments were compared. Participants viewed dynamic film sequences showing multiple display features and anticipated what would happen next. New and previously viewed action sequences were then presented in film or point-light display format. Participants attempted to recognize previously viewed sequences. Skilled participants demonstrated superior anticipation skill and were more sensitive in discriminating previously viewed and novel clips than their less-skilled counterparts. Skilled participants fixated more locations than less-skilled participants, implying that they process dynamic scenes as a series of relations between display features. The patterns of eye fixation measures differed between the anticipation and recognition tasks suggesting that different processes underpin these two types of judgments. Copyright © 2009 John Wiley & Sons, Ltd. [source]