Complexity constrained rate-distortion optimization of sign language video using an objective intelligibility metric

Frank M. Ciaramello; Sheila S. Hemami

doi:10.1117/12.768053

28 January 2008 Complexity constrained rate-distortion optimization of sign language video using an objective intelligibility metric

Frank M. Ciaramello, Sheila S. Hemami

Author Affiliations +

Proceedings Volume 6822, Visual Communications and Image Processing 2008; 682213 (2008) https://doi.org/10.1117/12.768053
Event: Electronic Imaging, 2008, San Jose, California, United States

Abstract

Sign language users are eager for the freedom and convenience of video communication over cellular devices. Compression of sign language video in this setting offers unique challenges. The low bitrates available make encoding decisions extremely important, while the power constraints of the device limit the encoder complexity. The ultimate goal is to maximize the intelligibility of the conversation given the rate-constrained cellular channel and power constrained encoding device. This paper uses an objective measure of intelligibility, based on subjective testing with members of the Deaf community, for rate-distortion optimization of sign language video within the H.264 framework. Performance bounds are established by using the intelligibility metric in a Lagrangian cost function along with a trellis search to make optimal mode and quantizer decisions for each macroblock. The optimal QP values are analyzed and the unique structure of sign language is exploited in order to reduce complexity by three orders of magnitude relative to the trellis search technique with no loss in rate-distortion performance. Further reductions in complexity are made by eliminating rarely occuring modes in the encoding process. The low complexity SL optimization technique increases the measured intelligibility up to 3.5 dB, at fixed rates, and reduces rate by as much as 60% at fixed levels of intelligibility with respect to a rate control algorithm designed for aesthetic distortion as measured by MSE.

Citation Download Citation

Frank M. Ciaramello and Sheila S. Hemami "Complexity constrained rate-distortion optimization of sign language video using an objective intelligibility metric", Proc. SPIE 6822, Visual Communications and Image Processing 2008, 682213 (28 January 2008); https://doi.org/10.1117/12.768053

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available