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. 25, 1997
Filed:
Apr. 24, 1996
Applicant:
Inventors:
Assignee:
U.S. Philips Corporation, NY, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04N / ; H04N / ;
U.S. Cl.
CPC ...
348405 ; 348419 ;
Abstract
The picture quality of an MPEG-coded video signal can be improved considerably by modifying selected coefficients after conventional quantization, for example by rendering them zero. The modification is such that the Lagrangian cost D+.lambda.R (D is distortion, R is bitrate) is minimal for a given value of a Lagrange multiplier .lambda.. A relatively simple process is disclosed in which the value of .lambda. is calculated by means of statistical analysis (6) of the picture to be coded. The statistical analysis comprises the estimation of the RD curve on the basis of the amplitude distribution of the coefficients. The searched .lambda. is the derivative of this curve at the desired bitrate.