US5387946A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring noise in video signals
Assignee: Vantiva SA
•
Filing: 1993-03-22
•
Granted: 1995-02-07
•
Expires: 2013-03-22
Abstract
Abstract A method of measuring noise in a television signal includes the steps of storing an estimated noise value N. The activity values A of blocks of pixels are measured and periodically compared with the estimated noise value N. A first correction value C v1 is added to the estimated value when A>N and a second correction value C v2 is subtracted from the noise value N when A≦N. The second correction value C v2 is substantially greater than the first correction value C v1 .
Inventors
- 👤 Michael Knee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:11
CPC Classifications
H; H04; H04N; H04N17/00; G; G01; G01R; G01R29/00; G01R29/26
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
A method of applying a low noise signal to a television display by measuring noise in a television signal comprising the steps of: storing an estimated noise value N; measuring the activity values A of blocks of pixels; periodically comparing said activity value A with said estimated noise value N; adding a first correction value C v1 to said estimated value when A>N and subtracting a second correction value C v2 when A≦N, said second correction value C v2 being in the order of 10 to 100 times greater than said first correction value C v1 ; and determining said activity values A by subtracting the value of each pixel from the mean value of all pixels within the block.
Claim 2
Independent Claim
120 words
A method of applying a low noise signal to a television display by measuring noise in a television signal comprising the steps of: storing an estimated noise value N; measuring the activity values A of blocks of pixels; periodically comparing said activity value A with said estimated noise value N; adding a first correction value C v1 to said estimated value when A>N and subtracting a second correction value C v2 when A≦N, said second correction value C v2 being in the order of 10 to 100 times greater than said first correction value C v1 ; and determining said activity values A by subtracting the value of each pixel from the mean value of all pixels within the block.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein said activity values are determined by filtering said television signal and taking the difference between the filtered signal and a predicted value.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein said activity values are determined by filtering said television signal with a one-dimensional analog high pass filter.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein said activity values are determined by summing the absolute values of the differences obtained by said subtraction.
Claim 6
Dependent Claim
34 words
The method of claim 1 wherein said activity values A are determined at a first period and said noise values N are accumulated and change at a second period less than said first period.
Claim 7
Dependent Claim
39 words
The method of claim 5 further including the step of taking the logarithm of said activity value A before comparing said activity value to said noise value N, and adding a fixed correction value to said noise value N.
Claim 8
Dependent Claim
164 words
Apparatus for measuring noise in a video signal comprising: a pseudorandom noise generator; means responsive to said noise generator for receiving blocks of data representative of activity in said video signal at intervals determined by said noise generator; means for calculating the mean values of for each block of data; means for subtracting said mean values from values of the current block to establish difference values; means for calculating absolute values of said difference values; means for summing said absolute values for each block and providing activity values for each block; means for storing estimated noise values; means for comparing said activity values with said noise values; and means responsive to said means for comparing for adding a first correction value to said estimated noise value when said activity value exceeds said noise value and for subtracting a second correction value from said value when said noise value exceeds said activity value, said second correction value being substantially greater than said first correction value.
Claim 9
Dependent Claim
164 words
Apparatus for measuring noise in a video signal comprising: a pseudorandom noise generator; means responsive to said noise generator for receiving blocks of data representative of activity in said video signal at intervals determined by said noise generator; means for calculating the mean values of for each block of data; means for subtracting said mean values from values of the current block to establish difference values; means for calculating absolute values of said difference values; means for summing said absolute values for each block and providing activity values for each block; means for storing estimated noise values; means for comparing said activity values with said noise values; and means responsive to said means for comparing for adding a first correction value to said estimated noise value when said activity value exceeds said noise value and for subtracting a second correction value from said value when said noise value exceeds said activity value, said second correction value being substantially greater than said first correction value.
References Cited (Backward Citations)
US4074201A
Cited
US4249209A
Cited
EP0109037A1
Cited
US4442454A
Cited
US4873574A
Cited
US5161018A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-06 | 1998-08-08 | 1999-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-06 | 2002-08-08 | 2003-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-06 | 2006-08-08 | 2007-02-07 | $7700.00 | Window Closed / Lapsed |