US5222080A
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Method and apparatus for signal reconstruction
Assignee: Qwest Communications International Inc
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Filing: 1991-03-20
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Granted: 1993-06-22
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Expires: 2011-03-20
Abstract
Abstract A method for reconstructing an incomplete signal in a sub-band transmission system is disclosed. Signal degradation from signal loss in a sub-band transmission system may be avoided by formulating an error function, and finding an optimal signal which minimizes the error between the sub-band signals interpolated from received sub-band signals and the sub-band signals obtained by convolving an optimal reconstructed signal with the original analysis filters. The minimized system equation is solved to provide an optimal reconstructed output signal.
Inventors
- 👤 Yao Wang
- 👤 V. Ramamoorthy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:42
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L2025/03433; H04L2025/03439; H04L2025/03528
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
303 words
A method of constructing an output signal approximating an original signal from a set of sub-band signals, said method using a system having a system controller, a signal reconstruction system, and synthesis filters, wherein the set of sub-band signals is produced by inputting the original signal into a set of analysis filters, each of the filters having a known impulse response, and decimating the output from the set of analysis filters to produce the set of sub-band signals, wherein said original signal has a good segment and a bad segment, said good segment being a portion of the original signal where all sub-band signals in the set of sub-band signals are received by said system, said bad segment being a portion of the original signal where the set of sub-band signals is incomplete, the method comprising the steps of: (a) constructing a good region of an output signal corresponding to the good segment by inputting the sub-band signals of said good segment into said synthesis filters which are matched to the analysis filters; and (b) constructing a bad region of said output signal corresponding to the bad segment by: (i) receiving at least one sub-band signal from the set of sub-bands signals in said bad segment; and (ii) identifying an output signal ##EQU12## where i is the index identifying said received sub-band signals, B r are the indices of the received sub-band signals. H i is a matrix defining the impulse response of the analysis filters, w i are weighting coefficients, t is the operation of matrix transposition followed by complex conjugation, and f i B are the interpolated received sub-band signals, whereby f opt is said output signal; and (c) combining the good region of said output signal with the bad region of said output signal to form a complete output signal.
Claim 2
Independent Claim
303 words
A method of constructing an output signal approximating an original signal from a set of sub-band signals, said method using a system having a system controller, a signal reconstruction system, and synthesis filters, wherein the set of sub-band signals is produced by inputting the original signal into a set of analysis filters, each of the filters having a known impulse response, and decimating the output from the set of analysis filters to produce the set of sub-band signals, wherein said original signal has a good segment and a bad segment, said good segment being a portion of the original signal where all sub-band signals in the set of sub-band signals are received by said system, said bad segment being a portion of the original signal where the set of sub-band signals is incomplete, the method comprising the steps of: (a) constructing a good region of an output signal corresponding to the good segment by inputting the sub-band signals of said good segment into said synthesis filters which are matched to the analysis filters; and (b) constructing a bad region of said output signal corresponding to the bad segment by: (i) receiving at least one sub-band signal from the set of sub-bands signals in said bad segment; and (ii) identifying an output signal ##EQU12## where i is the index identifying said received sub-band signals, B r are the indices of the received sub-band signals. H i is a matrix defining the impulse response of the analysis filters, w i are weighting coefficients, t is the operation of matrix transposition followed by complex conjugation, and f i B are the interpolated received sub-band signals, whereby f opt is said output signal; and (c) combining the good region of said output signal with the bad region of said output signal to form a complete output signal.
Claim 3
Dependent Claim
29 words
The method of claim 1, wherein the weighting coefficients w i are equal to one (1) for the received sub-band signals and zero (0) for all other sub-band signals.
Claim 4
Dependent Claim
31 words
The method of claim 1, further including the step of transmitting the set of sub-band signals over a transmission network prior to receiving the set of sub-band signals by said system.
Claim 5
Dependent Claim
26 words
The method of claim 1, further including the step of parsing said sub-band signals into packets, and wherein the transmission network is a packet switched network.
Claim 6
Dependent Claim
14 words
The method of claim 1, wherein the original signal is a two-dimensional video image.
Claim 7
Dependent Claim
23 words
The method of claim 1, further including the step of interpolating the received sub-band signals f i by averaging the received sub-band signals.
Claim 8
Dependent Claim
32 words
The method of claim 1, wherein f opt is found by a gradient descent method by iteratively updating variable f k (x,y) by ##EQU13## where τ(f) is a nonlinear threshold function: ##EQU14##
Claim 9
Dependent Claim
284 words
A receiver for constructing an output signal which approximates an original signal from a set of sub-band signals, said set of sub-band signals produced by inputting the original signal into a set of analysis filters and decimated, each analysis filter having a known impulse response, the set of sub-band signals being transmitted over a packet switched network to the receiver, the original signal having a good segment and a bad segment, the good segment being a portion of the original signal of which the receiver receives all sub-band signals of the set, the bad segment being a portion of the original signal of which the receiver receives at least one of the sub-band signals from the set of sub-band signals, the receiver including: (a) means for determining the portions of the original signal which are good segments and bad segments; (b) means for constructing a good region of an output signal corresponding to a good segment by inputting said good segment into a set of synthesis filters matched to the analysis filters; (c) means for constructing a bad region of said output signal corresponding to a bad segment by identifying an output signal ##EQU15## where i is the index identifying said received sub-band signals, B r are the indices of the received sub-band signals, H i is a matrix defining the impulse response of the analysis filters, w i are weighting coefficients, t is the operation of matrix transposition followed by complex conjugation, and f i B are the interpolated received sub-band signals, whereby f opt is said output signal; and (d) combining said good region of said output signal with said bad region of said output signal to form a complete output signal.
Claim 10
Dependent Claim
284 words
A receiver for constructing an output signal which approximates an original signal from a set of sub-band signals, said set of sub-band signals produced by inputting the original signal into a set of analysis filters and decimated, each analysis filter having a known impulse response, the set of sub-band signals being transmitted over a packet switched network to the receiver, the original signal having a good segment and a bad segment, the good segment being a portion of the original signal of which the receiver receives all sub-band signals of the set, the bad segment being a portion of the original signal of which the receiver receives at least one of the sub-band signals from the set of sub-band signals, the receiver including: (a) means for determining the portions of the original signal which are good segments and bad segments; (b) means for constructing a good region of an output signal corresponding to a good segment by inputting said good segment into a set of synthesis filters matched to the analysis filters; (c) means for constructing a bad region of said output signal corresponding to a bad segment by identifying an output signal ##EQU15## where i is the index identifying said received sub-band signals, B r are the indices of the received sub-band signals, H i is a matrix defining the impulse response of the analysis filters, w i are weighting coefficients, t is the operation of matrix transposition followed by complex conjugation, and f i B are the interpolated received sub-band signals, whereby f opt is said output signal; and (d) combining said good region of said output signal with said bad region of said output signal to form a complete output signal.
Claim 11
Dependent Claim
29 words
The apparatus of claim 8, wherein the weighting coefficients w i are equal to one (1) for the received sub-band signals and zero (0) for all other sub-band signals.
Claim 12
Dependent Claim
20 words
The apparatus of claim 8, further including a transmission network for transmitting the set of sub-band signals to the receiver.
Claim 13
Dependent Claim
27 words
The apparatus of claim 8, wherein said transmission network is a packet switched network, said apparatus further including parsing means for parsing said sub-band signals into packets.
Claim 14
Dependent Claim
14 words
The apparatus of claim 11, wherein the original signal is a two-dimensional video image.
Claim 15
Independent Claim
296 words
A method of constructing an output signal approximating an original signal from a set of sub-band signals, said method using a system having a system controller, a signal reconstruction system, and synthesis filters, wherein the set of sub-band signals is produced by inputting the original signal into a set of analysis filters, each of the filters having a known impulse response, and decimating the output from the set of analysis filters to produce the set of sub-band signals, wherein said original signal has a good segment and a bad segment, said good segment being a portion of the original signal where all sub-band signals in the set of sub-band signals are received by said system, said bad segment being a portion of the original signal where the set of sub-band signals is incomplete, the method comprising the steps of: (a) constructing a good region of an output signal corresponding to the good segment by inputting the sub-band signals of said good segment into said synthesis filters which are matched to the analysis filters; and (b) constructing a bad region of said output signal corresponding to the bad segment by: (i) receiving at least one sub-band signal from the set of sub-band signals in said bad segment; and (ii) identifying an output signal f opt (x,y) which minimizes the following error: ##EQU16## where i is the index identifying a sub-signal, B r is a set of indices for said received sub-band signals, L is a set of points in said bad segment, h i (x,y) is an impulse response to an i-th analysis filter, f i B (x,y) is an interpolated sub-band signal from said received sub-band signals, modified at boundary points of set L in accordance with said good region, and w i are weighting coefficients.
Claim 16
Independent Claim
296 words
A method of constructing an output signal approximating an original signal from a set of sub-band signals, said method using a system having a system controller, a signal reconstruction system, and synthesis filters, wherein the set of sub-band signals is produced by inputting the original signal into a set of analysis filters, each of the filters having a known impulse response, and decimating the output from the set of analysis filters to produce the set of sub-band signals, wherein said original signal has a good segment and a bad segment, said good segment being a portion of the original signal where all sub-band signals in the set of sub-band signals are received by said system, said bad segment being a portion of the original signal where the set of sub-band signals is incomplete, the method comprising the steps of: (a) constructing a good region of an output signal corresponding to the good segment by inputting the sub-band signals of said good segment into said synthesis filters which are matched to the analysis filters; and (b) constructing a bad region of said output signal corresponding to the bad segment by: (i) receiving at least one sub-band signal from the set of sub-band signals in said bad segment; and (ii) identifying an output signal f opt (x,y) which minimizes the following error: ##EQU16## where i is the index identifying a sub-signal, B r is a set of indices for said received sub-band signals, L is a set of points in said bad segment, h i (x,y) is an impulse response to an i-th analysis filter, f i B (x,y) is an interpolated sub-band signal from said received sub-band signals, modified at boundary points of set L in accordance with said good region, and w i are weighting coefficients.
Claim 17
Dependent Claim
16 words
The method of claim 13, wherein said interpolated sub-band signal is acquired by an averaging operation.
Claim 18
Dependent Claim
23 words
The method of claim 13, wherein w i is chosen to be one for all i ε B r , and zero otherwise.
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) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-21 | 2004-12-21 | 2005-06-22 | $7700.00 | Window Closed / Lapsed |