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US5473384A
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Method of and system for enhancing distorted graphical information
Assignee: AT&T Inc
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Filing: 1993-12-16
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Granted: 1995-12-05
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Expires: 2013-12-16
Abstract
Abstract A system for and method of enhancing image/video signals to be decoded is disclosed. The system for and method of post-filtering uses, preferably, a temporal filter and a spatial filter, both of which are adaptive but neither is required to be adaptive. However, the system for and method of post-filtering may also be used with only an adaptive spatial post-filter. In this case, the performance is upper-bounded by the performance of systems using both the adaptive temporal and adaptive spatial post-filter.
Inventors
- 👤 Nuggehally S. Jayant
- 👤 Tsann-Shyong Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:23
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/90; H04N19/50; H04N19/503; H04N19/51; H04N19/527; H04N19/60; H04N19/61; H04N19/63; H04N19/85; H04N19/86
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
283 words
A method of enhancing a distorted video signal, the distorted video signal comprising a set of image matrices adapted to be transmitted over a transmission medium of a digital communications setup, the digital communications setup comprising a coder, a decoder, and the transmission medium, the method comprising the steps of: (a) filtering the set of image matrices with a first post-filter to generate a set of image intensity matrices; and (b) filtering the set of image intensity matrices with a second post-filter to generate a set of enhanced image signals, the filtering comprising: (1) classifying an image intensity matrix in the set of image intensity matrices into a set of edge pixels and a set of non-edge pixels; (2) filtering the set of edge pixels with a first sub-filter of the second filter to generate a first portion of an enhanced image matrix in the set of enhanced image signals; (3) classifying the non-edge pixels into a set of smooth pixels and non-smooth pixels; (4) filtering the smooth pixels with a second sub-filter of the second filter to generate a second portion of the enhanced image matrix; (5) classifying the non-smooth pixels into a set of moving pixels and a set of non-moving pixels, the set of non-moving pixels comprising a third portion of the enhanced image matrix; (6) filtering the set of moving pixels with a third sub-filter of the second filter to generate a fourth portion of the enhanced image matrix; (7) combining the first portion, the second portion, the third portion, and the fourth portion to form the enhanced image matrix; and (8) repeating steps (b)(1) through (b)(7) for other enhanced image matrices in the set of enhanced image signals.
Claim 2
Independent Claim
283 words
A method of enhancing a distorted video signal, the distorted video signal comprising a set of image matrices adapted to be transmitted over a transmission medium of a digital communications setup, the digital communications setup comprising a coder, a decoder, and the transmission medium, the method comprising the steps of: (a) filtering the set of image matrices with a first post-filter to generate a set of image intensity matrices; and (b) filtering the set of image intensity matrices with a second post-filter to generate a set of enhanced image signals, the filtering comprising: (1) classifying an image intensity matrix in the set of image intensity matrices into a set of edge pixels and a set of non-edge pixels; (2) filtering the set of edge pixels with a first sub-filter of the second filter to generate a first portion of an enhanced image matrix in the set of enhanced image signals; (3) classifying the non-edge pixels into a set of smooth pixels and non-smooth pixels; (4) filtering the smooth pixels with a second sub-filter of the second filter to generate a second portion of the enhanced image matrix; (5) classifying the non-smooth pixels into a set of moving pixels and a set of non-moving pixels, the set of non-moving pixels comprising a third portion of the enhanced image matrix; (6) filtering the set of moving pixels with a third sub-filter of the second filter to generate a fourth portion of the enhanced image matrix; (7) combining the first portion, the second portion, the third portion, and the fourth portion to form the enhanced image matrix; and (8) repeating steps (b)(1) through (b)(7) for other enhanced image matrices in the set of enhanced image signals.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the step of classifying the matrix comprises determining if an input image sequence is static, (d i (x,j)=0).
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein the first sub-filter is a multi-level median filter, the second sub-filter is a double median filter and the third sub-filter is a median filter.
Claim 5
Dependent Claim
25 words
The method of claim 1 wherein the first post-filter is comprised of a temporal post-filter and the second post-filter is comprised of a spatial post-filter.
Claim 6
Dependent Claim
16 words
The method of claim 4 wherein both the temporal post-filter and the spatial post-filter are adaptive.
Claim 7
Dependent Claim
18 words
The method of claim 1 further comprising the step of visually displaying the set of enhanced image matrices.
Claim 8
Dependent Claim
119 words
The method of claim 1 wherein the step of filtering the set of image matrices with the first post-filter comprises: (a) classifying an image matrix in the set of image matrices into a set of static pixels and a set of dynamic pixels, the set of static pixels comprising a first portion of an image intensity matrix in the set of image intensity matrices; (b) filtering the set of dynamic pixels with a motion compensating temporal filter to generate a second portion of the image intensity matrix; (c) combining the first portion with the second portion to form an image intensity matrix; and (d) repeating steps (a) through (c) for other image matrices in the set of image matrices.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-04 | 1999-06-05 | 1999-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-04 | 2003-06-05 | 2003-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-04 | 2007-06-05 | 2007-12-05 | $7700.00 | Window Closed / Lapsed |