Animated Impostors for Real-Time Display of Numerous Virtual Humans

Aubel, Amaury; Boulic, Ronan; Thalmann, Daniel

doi:10.1007/3-540-68686-x_2

Cited by 22 publications

(19 citation statements)

References 13 publications

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“…Giacomo et al [14] present methods for adapting a virtual human's representation and the resulting animation stream, and provide practical details for the integration of these methods into MPEG-4 and MPEG-21 architectures. Aubel et al [15] present a technique for using impostors to improve the display rate of animated characters by acting solely on the geometric and rendering information.…”

Section: Introductionmentioning

confidence: 99%

Model-Based Power Aware Compression Algorithms for MPEG-4 Virtual Human Animation in Mobile Environments

Chattopadhyay¹,

Bhandarkar²,

2007

IEEE Trans. Multimedia

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Abstract-MPEG-4 body animation parameters (BAP) are used for animation of MPEG-4 compliant virtual human-like characters. Distributed virtual reality applications and networked games on mobile computers require access to locally stored or streamed compressed BAP data. Existing MPEG-4 BAP compression techniques are inefficient for streaming, or storing, BAP data on mobile computers, because: 1) MPEG-4 compressed BAP data entails a significant number of CPU cycles, hence significant, unacceptable power consumption, for the purpose of decompression; 2) the lossy MPEG-4 technique of frame dropping to reduce network throughput during streaming leads to unacceptable animation degradation; and 3) lossy MPEG-4 compression does not exploit structural information in the virtual human model. In this article, we propose two novel algorithms for lossy compression of BAP data, termed as BAP-Indexing and BAP-Sparsing. We demonstrate how an efficient combination of the two algorithms results in a lower network bandwidth requirement and reduced power for data decompression at the client end when compared to MPEG-4 compression. The algorithm exploits the structural information in the virtual human model, thus maintaining visually acceptable quality of the resulting animation upon decompression. Consequently, the hybrid algorithm for BAP data compression is ideal for streaming of motion animation data to power-and network-constrained mobile computers.

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Section: Introductionmentioning

confidence: 99%

Model-Based Power Aware Compression Algorithms for MPEG-4 Virtual Human Animation in Mobile Environments

Chattopadhyay¹,

Bhandarkar²,

2007

IEEE Trans. Multimedia

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show abstract

“…Giacomo et al [14] present methods for adapting a virtual human's representation and the resulting animation stream, and practical details for the integration of these methods into MPEG-2 and MPEG-4 architectures. Aubel et al [15] present a technique of using imposters to improve the display rate of animated characters by acting solely on the geometric and rendering information.…”

Section: Introductionmentioning

confidence: 99%

Compression by indexing: an improvement over MPEG-4 body animation parameter compression

Chattopadhyay

Bhandarkar

2006

SPIE Proceedings

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Body Animation Parameters (BAPs) are used to animate MPEG-4 compliant virtual human-like characters. In order to stream BAPs in real time interactive environments, the BAPs are compressed for low bitrate representation using a standard MPEG-4 compression pipeline. However, the standard MPEG-4 compression is inefficient for streaming to power-constrained devices, since the streamed data requires extra power in terms of CPU cycles for decompression. In this paper, we have proposed and implemented an indexing technique for a BAP data stream, resulting in a compressed representation of the motion data. The resulting compressed representation of the BAPs is superior to the MPEG-4-based BAP compression in terms of both, required network throughput and power consumption at the client end to receive the compressed data stream and extract the original BAP data from the compressed representation. Although the resulting motion after decompression at the client end is lossy, the motion distortion is minimized by intelligent use of the hierarchical structure of the skeletal avatar model. Consequently, the proposed indexing method is ideal for streaming of motion data to power-and network-constrained devices such as PDAs, Pocket PCs and Laptop PCs operating in battery mode and other cellular devices in a mobile network environment.

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“…Giacomo et al [14] present methods for adapting a virtual human's representation and animation stream, and practical details for the integration of these methods into MPEG-4 and MPEG-21 architectures. Aubel et al [15] explain the technique of using imposters to improve the display rate of animated characters by acting solely on the geometric and rendering information.…”

Section: Introductionmentioning

confidence: 99%

Efficient compression and delivery of stored motion data for avatar animation in resource constrained devices

Chattopadhyay

Bhandarkar

2005

Proceedings of the ACM Symposium on Virtual Reality Software and Technology

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Animation of Virtual Humans (avatars) is done typically using motion data files that are stored on a client or streaming motion data from a server. Several modern applications require avatar animation in mobile networked virtual environments comprising of power constrained clients such as PDAs, Pocket-PCs and notebook PCs operating in battery mode. These applications call for efficient compression of the motion animation data in order to conserve network bandwidth, and save power at the client side during data reception and motion data reconstruction from the compressed file. In this paper, we have proposed and implemented a novel file format, termed the Quantized Motion Data (QMD) format, which enables significant, though lossy, compression of the motion data. The motion distortion resulting from the reconstructed motion from the QMD file is minimized by intelligent use of the hierarchical structure of the skeletal avatar model. The compression gained by using the QMD files for the motion data is more than twice achieved via standard MPEG-4 compression using a pipeline comprising of quantization, predictive encoding and arithmetic coding. In addition, considerably fewer CPU cycles are needed to reconstruct the motion data from the QMD files compared to motion data compressed using the MPEG-4 standard.

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Animated Impostors for Real-Time Display of Numerous Virtual Humans

Cited by 22 publications

References 13 publications

Model-Based Power Aware Compression Algorithms for MPEG-4 Virtual Human Animation in Mobile Environments

Model-Based Power Aware Compression Algorithms for MPEG-4 Virtual Human Animation in Mobile Environments

Compression by indexing: an improvement over MPEG-4 body animation parameter compression

Efficient compression and delivery of stored motion data for avatar animation in resource constrained devices

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