17,498 research outputs found
A Survey of Ocean Simulation and Rendering Techniques in Computer Graphics
This paper presents a survey of ocean simulation and rendering methods in
computer graphics. To model and animate the ocean's surface, these methods
mainly rely on two main approaches: on the one hand, those which approximate
ocean dynamics with parametric, spectral or hybrid models and use empirical
laws from oceanographic research. We will see that this type of methods
essentially allows the simulation of ocean scenes in the deep water domain,
without breaking waves. On the other hand, physically-based methods use
Navier-Stokes Equations (NSE) to represent breaking waves and more generally
ocean surface near the shore. We also describe ocean rendering methods in
computer graphics, with a special interest in the simulation of phenomena such
as foam and spray, and light's interaction with the ocean surface
TöRF: Time-of-Flight Radiance Fields for Dynamic Scene View Synthesis
Neural networks can represent and accurately reconstruct radiance fields for
static 3D scenes (e.g., NeRF). Several works extend these to dynamic scenes
captured with monocular video, with promising performance. However, the
monocular setting is known to be an under-constrained problem, and so methods
rely on data-driven priors for reconstructing dynamic content. We replace these
priors with measurements from a time-of-flight (ToF) camera, and introduce a
neural representation based on an image formation model for continuous-wave ToF
cameras. Instead of working with processed depth maps, we model the raw ToF
sensor measurements to improve reconstruction quality and avoid issues with low
reflectance regions, multi-path interference, and a sensor's limited
unambiguous depth range. We show that this approach improves robustness of
dynamic scene reconstruction to erroneous calibration and large motions, and
discuss the benefits and limitations of integrating RGB+ToF sensors that are
now available on modern smartphones.Comment: Accepted to NeurIPS 2021. Web page: https://imaging.cs.cmu.edu/torf/
NeurIPS camera ready updates -- added quantitative comparisons to new
methods, visual side-by-side comparisons performed on larger baseline camera
sequence
Spatial Sound Rendering – A Survey
Simulating propagation of sound and audio rendering can improve the sense of realism and the immersion both in complex acoustic environments and dynamic virtual scenes. In studies of sound auralization, the focus has always been on room acoustics modeling, but most of the same methods are also applicable in the construction of virtual environments such as those developed to facilitate computer gaming, cognitive research, and simulated training scenarios. This paper is a review of state-of-the-art techniques that are based on acoustic principles that apply not only to real rooms but also in 3D virtual environments. The paper also highlights the need to expand the field of immersive sound in a web based browsing environment, because, despite the interest and many benefits, few developments seem to have taken place within this context. Moreover, the paper includes a list of the most effective algorithms used for modelling spatial sound propagation and reports their advantages and disadvantages. Finally, the paper emphasizes in the evaluation of these proposed works
SLM simulation and MonteCarlo path tracing for computer-generated holograms
Computer holography is a growing research field that must pay attention to two main issues concerning computing effort: the visualization of a 3D virtual scene with photo-realistic quality and the bottleneck related to hologram digitizalition and visualization limits. This work shows a computational approach based on a Monte Carlo path-tracing algorithm, which accounts for both geometrical and physical phenomena involved in hologram generation, and, therefore, makes a feasible estimation of computing time costs. As these holograms also require yet unavailable visualization devices, their behavior needs to be simulated by computer techniques
Life-Sized Audiovisual Spatial Social Scenes with Multiple Characters: MARC & SMART-I²
International audienceWith the increasing use of virtual characters in virtual and mixed reality settings, the coordination of realism in audiovisual rendering and expressive virtual characters becomes a key issue. In this paper we introduce a new system combining two systems for tackling the issue of realism and high quality in audiovisual rendering and life-sized expressive characters. The goal of the resulting SMART-MARC platform is to investigate the impact of realism on multiple levels: spatial audiovisual rendering of a scene, appearance and expressive behaviors of virtual characters. Potential interactive applications include mediated communication in virtual worlds, therapy, game, arts and elearning. Future experimental studies will focus on 3D audio/visual coherence, social perception and ecologically valid interaction scenes
Perceptually Driven Interactive Sound Propagation for Virtual Environments
Sound simulation and rendering can significantly augment a user‘s sense of presence in virtual environments. Many techniques for sound propagation have been proposed that predict the behavior of sound as it interacts with the environment and is received by the user. At a broad level, the propagation algorithms can be classified into reverberation filters, geometric methods, and wave-based methods. In practice, heuristic methods based on reverberation filters are simple to implement and have a low computational overhead, while wave-based algorithms are limited to static scenes and involve extensive precomputation. However, relatively little work has been done on the psychoacoustic characterization of different propagation algorithms, and evaluating the relationship between scientific accuracy and perceptual benefits.In this dissertation, we present perceptual evaluations of sound propagation methods and their ability to model complex acoustic effects for virtual environments. Our results indicate that scientifically accurate methods for reverberation and diffraction do result in increased perceptual differentiation. Based on these evaluations, we present two novel hybrid sound propagation methods that combine the accuracy of wave-based methods with the speed of geometric methods for interactive sound propagation in dynamic scenes.Our first algorithm couples modal sound synthesis with geometric sound propagation using wave-based sound radiation to perform mode-aware sound propagation. We introduce diffraction kernels of rigid objects,which encapsulate the sound diffraction behaviors of individual objects in the free space and are then used to simulate plausible diffraction effects using an interactive path tracing algorithm. Finally, we present a novel perceptual driven metric that can be used to accelerate the computation of late reverberation to enable plausible simulation of reverberation with a low runtime overhead. We highlight the benefits of our novel propagation algorithms in different scenarios.Doctor of Philosoph
Feeling crowded yet?: Crowd simulations for VR
With advances in virtual reality technology and its multiple applications, the need for believable, immersive virtual environments is increasing. Even though current computer graphics methods allow us to develop highly realistic virtual worlds, the main element failing to enhance presence is autonomous groups of human inhabitants. A great
number of crowd simulation techniques have emerged in the last decade, but critical details in the crowd's movements and appearance do not meet the standards necessary to convince VR participants that they are present in a real crowd. In this paper, we review recent advances in the creation of immersive virtual crowds and discuss areas that require further work to turn these simulations into more fully immersive and believable experiences.Peer ReviewedPostprint (author's final draft
Object-based audio reproduction and the audio scene description format
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The introduction of new techniques for audio reproduction such as HRTF-based technology, wave field synthesis and higher-order Ambisonics is accompanied by a paradigm shift from channel-based to object-based transmission and storage of spatial audio. Not only is the separate coding of source signal and source location more efficient considering the number of channels used for reproduction by large loudspeaker arrays, it also opens up new options for a user-controlled interactive sound field design. This article describes the need for a common exchange format for object-based audio scenes, reviews some existing formats with potential to meet some of the requirements and finally introduces a new format called Audio Scene Description Format (ASDF) and presents the SoundScape Renderer, an audio reproduction software which implements a draft version of the ASDF
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