US3952186A
Expired / Lapsed
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Apparatus for the generation of a two-dimensional discrete fourier transform
Assignee: United States Department of the Navy
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Filing: 1975-02-10
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Granted: 1976-04-20
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Expires: 1995-02-10
Abstract
Abstract An apparatus for the generation of a two-dimensional discrete Fourier transform of an input signal developed from data within a data block, or field, having a size of N1 by N2 data points, N1 and N2 being relatively prime with respect to each other, the transforms being in a form suitable for subsequent electronic processing. The apparatus comprises an input scan apparatus connectable to the N1 by N2 two-dimensional data field comprising the input signal, such as a television viewing field. The apparatus receives and scans in proper order, or sequence, the N1 by N2 input data so that the subsequently generated one-dimensional Fourier transform of the length N1 N2 serial data string is identical to an N1 by N2 two-dimensional discrete Fourier transform of the N1 by N2 input data samples. A serial-access one-dimensional discrete Fourier transform (DFT) device, connected to the input scan generator, generates a one-dimensional discrete Fourier transform of the length N1 N2 serial data string.
Inventors
- 👤 Jeffrey M. Speiser
- 👤 Harper John Whitehouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:30
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10; G06F17/14; G06F17/147; H; H04; H04N; H04N19/00; H04N19/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
157 words
An apparatus for the generation of two-dimensional discrete Fourier transforms of an input signal developed from a data field having a size of N 1 by N 2 , N 1 and N 2 being relatively prime with respect to each other, comprising: an input scan apparatus for scanning the N 1 by N 2 two-dimensional data field comprising the input signal, which receives and scans in such an order, or sequence, the N 1 by N 2 input data samples in the field so that a subsequently generated one-dimensional Fourier transform of a length N 1 N 2 serial data string is identical to an N 1 by N 2 two-dimensional discrete Fourier transform of the N 1 by N 2 input data samples; and a serial-access one-dimensional discrete Fourier transform (DFT) device, connected to the input scan generator, for generating a one-dimensional discrete Fourier transform of the length N 1 N 2 serial data string.
Claim 2
Independent Claim
157 words
An apparatus for the generation of two-dimensional discrete Fourier transforms of an input signal developed from a data field having a size of N 1 by N 2 , N 1 and N 2 being relatively prime with respect to each other, comprising: an input scan apparatus for scanning the N 1 by N 2 two-dimensional data field comprising the input signal, which receives and scans in such an order, or sequence, the N 1 by N 2 input data samples in the field so that a subsequently generated one-dimensional Fourier transform of a length N 1 N 2 serial data string is identical to an N 1 by N 2 two-dimensional discrete Fourier transform of the N 1 by N 2 input data samples; and a serial-access one-dimensional discrete Fourier transform (DFT) device, connected to the input scan generator, for generating a one-dimensional discrete Fourier transform of the length N 1 N 2 serial data string.
Claim 3
Dependent Claim
24 words
The apparatus according to claim 1, wherein: the input scan apparatus scans selectively according to any one of the sequences shown in Table 1.
Claim 4
Dependent Claim
67 words
The apparatus according to claim 1, wherein the input scan apparatus comprises: an imaging device which receives and stores the data from the two-dimensional data field; and an input scan generator which scans the stored data in the imaging device, the stored data being scanned at discrete data points having coordinate values j 1 and j 2 , j 1 and j 2 forming a coordinate system.
Claim 5
Dependent Claim
39 words
The apparatus according to claim 3, wherein the input scan generator scans the stored data at discrete data points j 1 and j 2 , the system of coordinates j 1 and j 2 comprising an orthogonal coordinate system.
Claim 6
Dependent Claim
39 words
The apparatus according to claim 3, wherein the input scan apparatus further comprises: a pair of digital-to-analog (D/A) converters connected between the input scan generator and the imaging device, to supply analog scanning voltages for scanning the imaging device.
Claim 7
Dependent Claim
13 words
The apparatus according to claim 5, wherein the imaging device is a vidicon.
Claim 8
Dependent Claim
177 words
The apparatus according to claim 1, wherein the input scan apparatus includes an input scan generator which comprises: a first recursive filter; the recursion relationship being j 1 (k+1)=j 1 (k) + j 1 (1), (Mod N 1 ), k=0, . . . , N 1 N 2 , the output of the filter comprising a j 1 -coordinate scan output; a second recursive filter, the recursion relationship being j 2 (k+1)=j 2 (k)+j 2 (1), (Mod N 2 ), the output of this filter comprising a j 2 -coordinate scan output, j 1 and j 2 forming a coordinate system; and a double-pole double-throw initialization switch, which switches in a manner so that at one position of the switch, at a first sample time of the data field, the j 1 - and j 2 -coordinate scan outputs are zero, but at the succeeding N-1 sample times the scan outputs are the outputs of the modulo N 1 and modulo N 2 recursive filters, the two outputs comprising the input to the discrete Fourier transform device.
Claim 9
Dependent Claim
17 words
The apparatus according to claim 7, further comprising: a timing source, connected to the input scan generator.
Claim 10
Dependent Claim
126 words
The apparatus according to claim 8, further comprising: means connected to the timing source for delaying the signals from the timing source; an output scan generator whose input is connected to the output of the delay means, which keep track of the specific two-dimensional transform point which is currently being produced by the one-dimensional transform device; a selection gate, which has one input connected to the output of the DFT device and another input connected to the output of the output scan generator, the gate selecting the specific frequencies, corresponding to specific coordinate values, which are to be transmitted; and a read-only memory (ROM), serving as a selection table, whose output is connected to the selection gate, which stores information as to which frequencies are rejected.
Claim 11
Dependent Claim
24 words
The apparatus according to claim 9, wherein the read-only memory stores information as to which higher frequencies of the selected specific frequencies are rejected.
Claim 12
Dependent Claim
22 words
The apparatus according to claim 9, wherein the selection table also stores information as to required quantization for various frequencies of interest.
Claim 13
Dependent Claim
112 words
The image transmission system according to claim 11 further comprising: a first modem, functioning as a modulator, whose input is connected to the output of the selection gate, which modulates the input signal; a signal channel, whose input is connected to the output of the first modem, for transmitting the modulated signal; a second modem, functioning as a demodulator, whose input is connected to the output of the signal channel, for demodulating the modulated signal; an inverse transform device whose input is connected to the output of the second modem; and a display device, whose input is connected to the output of the inverse transform device, which displays the reduced redundancy image.
References Cited (Backward Citations)
US3686490A
Cited
US3775602A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-20 | 1979-10-20 | 1980-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-20 | 1983-10-20 | 1984-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-20 | 1987-10-20 | 1988-04-20 | $7700.00 | Window Closed / Lapsed |