US6018753A
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Interpolating filter banks in arbitrary dimensions
Assignee: Nokia of America Corp
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Filing: 1997-07-29
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Granted: 2000-01-25
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Expires: 2017-07-29
Abstract
Abstract Interpolating filter banks are constructed for use with signals which may be represented as a lattice of arbitrary dimension d. The filter banks include M channels, where M is greater than or equal to two. A given filter bank is built by first computing a set of shifts tau i as D-1 ti, i=1,2, . . . M-1, where ti is a set of coset representatives taken from a unit cell of the input signal lattice, and D is a dilation matrix having a determinant equal to M. A polynomial interpolation algorithm is then applied to determine weights for a set of M-1 predict filters Pi having the shifts tau i. A corresponding set of update filters Ui are then selected as Ui=Pi*/M, where Pi* is the adjoint of the predict filter Pi. The resulting predict and update filters are arranged in a lifting structure such that each of the predict and update filters are associated with a pair of the M channels of the filter bank. The input signal applied to the filter bank is downsampled in each of the M channels, and then interpolated using the M-1 predict filters and the M-1 update filters. The downsampled and interpolated signal may be reconstructed using complementary interpolation and upsampling operations.
Inventors
- 👤 Jelena Kovacevic
- 👤 Wim Sweldens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:34
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/4007; G06T3/4084
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
109 words
A method of filtering an input signal in a filter bank, the method comprising the steps of: downsampling the input signal in each of M channels of the filter bank, where M is greater than two; and processing downsampled versions of the input signal in at least a first predict filter and at least one update filter, wherein the first predict filter and the update filter are associated with a pair of the M channels of the filter bank, and the update filter is selected as the adjoint of a predict filter having an order less than or equal to that of the first predict filter, divided by M.
Claim 2
Independent Claim
109 words
A method of filtering an input signal in a filter bank, the method comprising the steps of: downsampling the input signal in each of M channels of the filter bank, where M is greater than two; and processing downsampled versions of the input signal in at least a first predict filter and at least one update filter, wherein the first predict filter and the update filter are associated with a pair of the M channels of the filter bank, and the update filter is selected as the adjoint of a predict filter having an order less than or equal to that of the first predict filter, divided by M.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein the update filter is selected as the adjoint of the first predict filter divided by M.
Claim 4
Dependent Claim
77 words
The method of claim 1 wherein the processing step further includes processing downsampled versions of the input signal in a set of M-1 predict filters and a corresponding set of M-1 update filters, wherein each of the predict and update filters are associated with a pair of the M channels of the filter bank, and at least a subset of the update filters are each selected as the adjoint of the corresponding predict filter divided by M.
Claim 5
Dependent Claim
54 words
The method of claim 3 further including the step of delaying the input signal in each of the last M-1 of the M channels, such that a delay of t i is applied to the signal in the ith channel, for i=2, . . . M-1, prior to downsampling the signal in that channel.
Claim 6
Dependent Claim
62 words
The method of claim 3 wherein the M-1 predict filters provide shifts τ i which are generated as τ i =D -1 t i , i=1, 2, . . . M-1, where D is a dilation matrix having a determinant equal to M, and the t i are coset representatives taken from a unit cell of a lattice representation of the signal.
Claim 7
Dependent Claim
111 words
The method of claim 3 further including the steps of: processing interpolated downsampled versions of the input signal in a second set of M-1 predict filters and a corresponding second set of M-1 update filters, wherein each of the predict and update filters in the second sets are associated with a pair of the M channels of the filter bank; upsampling portions of the signal in each of the M channels of the filter bank, after processing in the second sets of predict and update filters; and recombining outputs of the M channels of the filter bank to generate an output signal having substantially the same resolution as the input signal.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein the input signal is in the form of a lattice of sample points.
Claim 9
Dependent Claim
28 words
The method of claim 7 wherein the input signal is in the form of a lattice of sample points having dimension d greater than or equal to one.
Claim 10
Dependent Claim
105 words
A filter bank for filtering an input signal, comprising: a downsampler for downsampling the input signal in each of M channels of the filter bank, where M is greater than two; and at least a first predict filter and at least one update filter, for processing resulting downsampled versions of the input signal, wherein the first predict filter and the update filter are associated with a pair of the M channels of the filter bank, and the update filter is selected as the adjoint of a predict filter having an order less than or equal to that of the first predict filter, divided by M.
Claim 11
Dependent Claim
105 words
A filter bank for filtering an input signal, comprising: a downsampler for downsampling the input signal in each of M channels of the filter bank, where M is greater than two; and at least a first predict filter and at least one update filter, for processing resulting downsampled versions of the input signal, wherein the first predict filter and the update filter are associated with a pair of the M channels of the filter bank, and the update filter is selected as the adjoint of a predict filter having an order less than or equal to that of the first predict filter, divided by M.
Claim 12
Dependent Claim
23 words
The filter bank of claim 9 wherein the update filter is selected as the adjoint of the first predict filter divided by M.
Claim 13
Dependent Claim
92 words
The filter bank of claim 9 wherein the at least one predict filter is part of a set of M-1 predict filters and the at least one update filter is part of a corresponding set of M-1 update filters for processing resulting downsampled versions of the input signal, wherein each of the predict and update filters are associated with a pair of the M channels of the filter bank, and at least a subset of the update filters are each selected as the adjoint of the corresponding predict filter divided by M.
Claim 14
Dependent Claim
58 words
The filter bank of claim 11 further including a plurality of delay elements for delaying the input signal in each of the last M-1 of the M channels, such that a delay of t i is applied to the signal in the ith channel, for i=2, . . . M-1, prior to downsampling the signal in that channel.
Claim 15
Dependent Claim
63 words
The filter bank of claim 11 wherein the M-1 predict filters provide shifts τ i which are generated as τ i =D -1 t i , i=1, 2, . . . M1, where D is a dilation matrix having a determinant equal to M, and the t i are coset representatives taken from a unit cell of a lattice representation of the signal.
Claim 16
Dependent Claim
119 words
The filter bank of claim 11 further including: a second set of M-1 predict filters and a corresponding second set of M-1 update filters, for processing interpolated downsampled versions of the input signal, wherein each of the predict and update filters in the second sets are associated with a pair of the M channels of the filter bank; and an upsampler in each of the M channels for upsampling portions of the signal in each of the M channels, after processing in the second sets of predict and update filters; and a signal combiner for recombining outputs of the M channels of the filter bank to generate an output signal having substantially the same resolution as the input signal.
Claim 17
Dependent Claim
20 words
The filter bank of claim 9 wherein the input signal is in the form of a lattice of sample points.
Claim 18
Dependent Claim
29 words
The filter bank of claim 15 wherein the input signal is in the form of a lattice of sample points having dimension d greater than or equal to one.
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) | 2003-01-24 | 2003-07-26 | 2004-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-24 | 2007-07-26 | 2008-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-24 | 2011-07-26 | 2012-01-25 | $7700.00 | Window Closed / Lapsed |