The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 09, 2001
Filed:
Oct. 24, 1997
Jelena Kovacevic, New York, NY (US);
Francis Man Lung Ng, Milpitas, CA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A signal transmission system assigns portions of an image or other type of signal to packets so as to provide an approximate equalization of the signal energy across the packets. As a result, the quality of a reconstructed signal in the presence of a given amount of packet loss is substantially the same regardless of the particular packets which are lost. In one possible implementation, the signal is separated into subbands using a cosine-modulated orthonormal filter bank. The subbands are then assigned to packets in accordance with an energy equalization algorithm such that the cumulative energies of the packets are approximately equal. In another implementation, an image signal is scrambled such that pixels in the image are mapped to different spatial positions, thereby producing a whitened image. The whitened image is then separated into subbands, and the subbands are assigned deterministically to the packets. Similar whitening techniques can be also used with non-image signals. These and other implementations of the invention provide graceful degradation in reconstructed signal quality in the presence of packet loss during transmission.