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:
May. 19, 1981
Filed:
Sep. 18, 1978
Applicant:
Inventors:
William F Schreiber, Cambridge, MA (US);
Donald E Troxel, Belmont, MA (US);
Assignee:
Massachusetts Institute of Technology, Cambridge, MA (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
358138 ; 375-1 ;
Abstract
Processing of digitally-coded pictures to improve perceived quality without increasing transmission channel capacity, featuring dividing the video signal into a low, middle and high frequency signals (16, 26), finely quantizing the low frequency signal (18), adding pseudo-random noise (33) to the middle frequency signal prior to quantizing (28), enhancing (36) and adding pseudo-random noise (48) prior to coarsely quantizing (50) the high frequency signal. The pseudo-random signals are subtracted (37, 52) from the respective signals at the receiver.