Patent EP0659019A2 successfully refreshed from Google Patents.
EP0659019A2
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EP
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Method of and system for enhancing distorted graphical information
Assignee: AT&T Inc
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Filing: 1994-12-01
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Granted: —
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Expires: 2014-12-01
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 (e.g., 110) and a spatial filter (e.g., 112), 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 Sampath Jayant
- 👤 Tsann-Shyong Liu
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:02
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: 18
Claim 1
Independent Claim
52 words
A system for enhancing a set of distorted image signals, the set of distorted image signals adapted to be transmitted over a transmission medium of a digital communications setup, the system comprising an adaptive spatial post-filter for filtering the set of distorted image signals to generate a set of enhanced image signals.
Claim 2
Dependent Claim
31 words
The system of claim 1 wherein distortion is due to quantization error introduced in low bit rate coding of a coder, the coder being a portion of the digital communications setup.
Claim 3
Independent Claim
71 words
A system for enhancing a set of distorted image signals, the set of distorted image signals adapted to be transmitted over a transmission medium of a digital communications setup, the system comprising: (a) first post-filter means for filtering the set of distorted image signals to generate a set of first signals; and (b) second post-filter means for filtering the set of first signals to generate a set of enhanced image signals.
Claim 4
Dependent Claim
27 words
The system of claim 3 wherein the first post-filtering means is comprised of a temporal post-filter and the second post-filter means is comprised of a spatial post-filter.
Claim 5
Dependent Claim
16 words
The system of claim 4 wherein both the temporal post-filter and the spatial post-filter are adaptive.
Claim 6
Independent Claim
62 words
A method for enhancing a set of distorted image signals 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 step of post-filtering the set of distorted image signals with an adaptive spatial post-filter to generate a set of enhanced image signals.
Claim 7
Dependent Claim
21 words
The method of claim 6 wherein distortion is due to quantization error introduced in low bit rate coding of the coder.
Claim 8
Independent Claim
71 words
A method for enhancing a set of distorted image signals, the set of distorted image signals adapted to be transmitted over a transmission medium of a digital communications setup, the method comprising: (a) filtering the set of distorted image signals with a first post-filter to generate a set of first signals; and (b) filtering the set of first signals with a second post-filter to generate a set of enhanced image signals.
Claim 9
Dependent Claim
19 words
The method of claim 6 or 8 further comprising the step of displaying the set of enhanced image signals.
Claim 10
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 11
Dependent Claim
24 words
The method of claim 10 wherein the step of classifying the matrix comprises determining if an input image sequence is static, (d i (x,j)=0).
Claim 12
Dependent Claim
30 words
The method of claim 10 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 13
Dependent Claim
27 words
The method of claim 8 or 10 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 14
Dependent Claim
16 words
The method of claim 13 wherein both the temporal post-filter and the spatial post-filter are adaptive.
Claim 15
Dependent Claim
18 words
The method of claim 10 further comprising the step of visually displaying the set of enhanced image matrices.
Claim 16
Dependent Claim
119 words
The method of claim 10 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.
Claim 17
Independent Claim
87 words
A system for enhancing a set of distorted image signals, the set of distorted image signals adapted to be transmitted over a transmission medium of a digital communications setup, the system comprising: (a) first means for post-filtering the set of distorted image signals to generate a set of first signals, the first means for post-filtering being temporal and adaptive; and (b) second means for post-filtering the set of first signals to generate a set of enhanced image signals, the second means for post-filtering being spatial and adaptive.
Claim 18
Dependent Claim
31 words
The system of claim 1, 3 or 17 further comprising a means for visual display, the set of enhanced image signals adapted to be displayed on the means for visual display.
References Cited (Backward Citations)
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