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:
Nov. 14, 1978
Filed:
Aug. 18, 1977
Frank W Mounts, Colts Neck, NJ (US);
Arun N Netravali, Matawan, NJ (US);
Birendra Prasada, Nun's Island, CA;
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
When a video signal is encoded using differential pulse code modulation (DPCM) techniques, the frequency of occurrence of the various quantizer output or representative levels is non-uniform; usually, low levels occur more frequently than high levels, and this characteristic can be used to advantage by applying the DPCM output to a variable length encoder before transmission. The present invention increases this advantage by intentionally forcing the quantizer output to particular levels when doing so is not harmful to the picture fidelity. By so doing, the entropy of the encoded signal is reduced by as much as 25 percent.