Biomechanical and Perceptual Constraints on the Bandwidth Requirements of Sign Language

Document Type

Article

Publication Date

3-1-2004

Abstract

Access to telecommunication systems by deaf users of sign language can be greatly enhanced with the incorporation of video conferencing in addition to text-based adaptations. However, the communication channel bandwidth is often challenged by the spatial requirements to represent the image in each frame and temporal demands to preserve the movement trajectory with a sufficiently high frame rate. Effective systems must balance the portion of a limited channel bandwidth devoted to the quality of the individual frames and the frame rate in order to meet their intended needs. Conventional video conferencing technology generally addresses the limitations of channel capacity by drastically reducing the frame rate, while preserving image quality. This produces a jerky image that disturbs the trajectories of the hands and arms, which are essential in sign language. In contrast, a sign language communication system must provide a frame rate that is capable of representing the kinematic bandwidth of human movement. Prototype sign language communication systems often attempt to maintain a high frame rate by reducing the quality of the image with lossy spatial compression. Unfortunately, this still requires a combined spatial and temporal data rate, which exceeds the limited channel of residential and wireless telephony. While spatial compression techniques have been effective in reducing the data, there has been no comparable compression of sign language in the temporal domain. Even modest reductions in the frame rate introduce perceptually disturbing flicker that decreases intelligibility. This paper introduces a method through which temporal compression on the order of 5 :1 can be achieved. This is accomplished by decoupling the biomechanical or kinematic bandwidth necessary to represent continuous movements in sign language from the perceptually determined critical flicker frequency.

Identifier

1542618489 (Scopus)

Publication Title

IEEE Transactions on Neural Systems and Rehabilitation Engineering

External Full Text Location

https://doi.org/10.1109/TNSRE.2003.821371

ISSN

15344320

PubMed ID

15068189

First Page

65

Last Page

72

Issue

1

Volume

12

Grant

IIS-9804707

Fund Ref

National Science Foundation

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