US4456982A
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Imaging system with multiple, simultaneous transmissions
Assignee: Thales SA
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Filing: 1981-10-08
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Granted: 1984-06-26
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Expires: 2001-10-08
Abstract
Abstract A bidimensional imaging system by echoes including a transmitting array and a receiving array. The transmitting array includes a row of transmitters (E 1 , E 2 , . . . , E i , E N ) parallel to a direction Oz and the receiving array includes a row of receivers in a direction Ox. All the transmitters simultaneously transmit signals with different codes. The signals received are demodulated and the real and imaginary components of these signals are applied to two multiplexing circuits (61.1, 61.2). After modulation the multiplexed signals are applied to a Fourier transformation circuit (63), which sequentially supplies reception channels V k (θ k ) for the direction referenced by angle θ k and which are stored in memories (66.1, 66.2). Other memories (70.1, 70.2) contain signals S i (φ i ) transmitted in an angular direction referenced by φ i . The two pairs of memories (66.1, 66.2 and 70.1, 70.2) are connected and the signals are applied after modulation to a convolver (61), which supplies signals of the bidimensional image. The imaging system has application to ultrasonic submarine cameras, submarine target classifiers, medical acoustic imaging and non-destructive tests.
Inventors
- 👤 Pierre Tournois
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:09
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/52017; G01S7/52085; G01S7/5209; G01S7/52093; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/8959; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/34; G10K11/341
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
283 words
An imaging system comprising: a transmiting array including plural omnidirectional transducers each simultaneously transmitting respective differently coded signals; a receiving array including plural tranducers each adapted to receive signals transmitted by said transmitting array and reflected off a target, each said receiving array tranducer producing a respective output signal; and means for processing the output signals produced by said receiving array tranducers, comprising, means for forming P reception channels and generating respective reception signals V 1 (θ), V 2 (θ 2 ), . . . V k (θ k ), . . . V p (θ p ) corresponding respectively to predetermined increments θ 1 , θ 2 , . . . θ k , . . . θ p along a predetermined angular coordinate θ, means for forming Q transmission channels along a second angular coordinate φ and for generating respective signals S i ,k (φ i , θ k ) corresponding respectively to predetermined increments φ 1 , φ 2 , . . . , φ i . . . φ q along a predetermined angular coordinate φ for each of said reception channels, wherein the signals S i ,k (φ i , θ k ) are the sum in amplitude and phase of the coded signals transmitted by said transmitting array in the direction referenced by angular coordinates φ i and θ k , means for performing matched filtering of each of said signals V k (θ k ) with a respective set of said signals S i ,k (φ i , θ k ) and for producing respective output signals, and means for forming P×Q image points based on the output signals produced by said matched filtering performing means.
Claim 2
Dependent Claim
283 words
An imaging system comprising: a transmiting array including plural omnidirectional transducers each simultaneously transmitting respective differently coded signals; a receiving array including plural tranducers each adapted to receive signals transmitted by said transmitting array and reflected off a target, each said receiving array tranducer producing a respective output signal; and means for processing the output signals produced by said receiving array tranducers, comprising, means for forming P reception channels and generating respective reception signals V 1 (θ), V 2 (θ 2 ), . . . V k (θ k ), . . . V p (θ p ) corresponding respectively to predetermined increments θ 1 , θ 2 , . . . θ k , . . . θ p along a predetermined angular coordinate θ, means for forming Q transmission channels along a second angular coordinate φ and for generating respective signals S i ,k (φ i , θ k ) corresponding respectively to predetermined increments φ 1 , φ 2 , . . . , φ i . . . φ q along a predetermined angular coordinate φ for each of said reception channels, wherein the signals S i ,k (φ i , θ k ) are the sum in amplitude and phase of the coded signals transmitted by said transmitting array in the direction referenced by angular coordinates φ i and θ k , means for performing matched filtering of each of said signals V k (θ k ) with a respective set of said signals S i ,k (φ i , θ k ) and for producing respective output signals, and means for forming P×Q image points based on the output signals produced by said matched filtering performing means.
Claim 3
Dependent Claim
28 words
An imaging system according to claim 1, wherein the matched filtering performing means comprises: Q filters in parallel for each signal of channel V k (θ k ).
Claim 4
Dependent Claim
43 words
An imaging system according to claim 1, wherein the matched filtering performing means comprises: means for performing the convolution of each signal of channel V k (θ k ) with Q time reversed signals S i ,k (φ i , θ k ).
Claim 5
Dependent Claim
101 words
An imaging system according to claim 3, wherein the convolution performing means comprises: an analog convolver using the propagation of elastic waves in solids, means for modulating the signals V k (θ k ) and S i ,k (φ i , θ k ), about a center frequency and in a band permitting the use of such a convolver, and means for sequentially convoluting channel V k (θ k ) Q times with the Q time-reverse signal S i ,k (φ i , θ k ) in a time less than 1/B, B being the frequency band of the signals received.
Claim 6
Dependent Claim
55 words
An imaging system according to claim 1, wherein the receiving array comprises: a linear array of N equidistant receivers wherein the depth of the receiving array tranducers in the most inclined direction is less than C/B, C being the propagation velocity of the signals received and B being the frequency band of the signals received.
Claim 7
Dependent Claim
70 words
An imaging system according to claim 5, comprising: a demodulation circuit, having applied thereto the signals received by each of said receiving array transducers, for supplying respective real and imaginary components of the corresponding receiving array transducer signal, and first and second multiplexers respectively having applied thereto real and imaginary components supplied by said demodulation circuit, the period T H of the multiplexing operations being such that NT H <1/B.
Claim 8
Dependent Claim
28 words
An imaging system according to claim 6, comprising: a Fourier transform circuit having the two multiplexed signals applied thereto for supplying the Fourier transform of these multiplexed signals.
Claim 9
Dependent Claim
60 words
An imaging system according to claim 7, comprising: analog means for performing the Fourier transform in an analog manner, including, a system of dispersive filters using the propagation of the elastic waves in solids supplying N signals of channels V k (θ k ) sequentially in time for a duration equal to NT H and which is well below 1/B.
Claim 10
Dependent Claim
33 words
An imaging system according to claim 8, comprising: means for demodulating the two multiplexed real and imaginary components about a center frequency and in a band permitting the use of said dispersive filters.
Claim 11
Dependent Claim
34 words
An imaging system according to claim 8, comprising: means for demodulating, the signals of channels V k (θ k ), and means for converting the demodulated real and imaginary components obtained into digital form.
Claim 12
Dependent Claim
23 words
An imaging system according to claim 10, comprising: a digital memory for storing the real and imaginary components of the N channel signals.
Claim 13
Dependent Claim
31 words
An imaging system according to claim 6, comprising: means for sampling the signal from each receiver at frequency 1/B such that N channel signals are supplied in the time interval 1/B.
Claim 14
Dependent Claim
52 words
An imaging system according to claims 11 or 12, comprising: means for writing data into the digital memory line by line, each line storing N channel signals corresponding to N directions θ 1 to θ N , wherein the memory is filled at the end of time T and has BT lines.
Claim 15
Dependent Claim
59 words
An imaging system according to claim 13, comprising: means for reading the digital memory column by column at speed 1/B and successively supplying the signals of channels V k (θ k ) for the duration T in the form of two real and imaginary components having BT samples, wherein the BT samples are read at period T H .
Claim 16
Dependent Claim
46 words
An imaging system according to claim 14, comprising: means for converting the two components of each signal of channel V k (θ k ) into analog form, and means for modulating the converted analog signals about the center frequency and in the band of the convolver.
Claim 17
Dependent Claim
94 words
An imaging system according to claim 15, comprising: another digital memory for storing the N×Q copies of the signals S i ,k (φ i , θ k ) of two real and imaginary components, each signal having BT samples, including, means for reading in each signal in the memory at speed 1/B and the BT samples of each signal at T H , means for converting the two components into analog form, and means for modulating the two components converted into analog form about the center frequency and in the band of the convolver.
Claim 18
Dependent Claim
52 words
An imaging system according to claim 16, comprising: the elastic wave convolver having applied thereto in synchronism the two modulated signals V k (θ k ) and S i ,k (φ i , θ k ), their duration being equal to BTT H , wherein QBTT H is chosen lower than 1/B.
Claim 19
Dependent Claim
23 words
An imaging system according to claim 29, wherein the transmitting array comprises: a linear array of transmitters positioned orthogonally to the receiving array.
Claim 20
Dependent Claim
45 words
An imaging system according to claims 2 or 14, comprising: means for transmitting each signal V k (θ k ) to said set of Q filters matched to signals S i ,k (φ i , θ k ) whose pulse response has a duration T.
Claim 21
Dependent Claim
46 words
An imaging system according to claim 19, comprising: means for modulating each signal V k (θ k ) about the center frequency and in the band of the matched filters, and said matched filters comprising analog filters based on the propagation of elastic waves in solids.
Claim 22
Dependent Claim
34 words
An imaging system according to claim 1, comprising: means for controlling said transducers to successively fulfil the functions of transmitters and receivers, and at least one of the transducers arrays arranged in ring-like manner.
Claim 23
Dependent Claim
25 words
An imaging system according to claim 1, comprising: said transmitting array transducers arranged in linear manner, and the receiving array transducers arranged in ring-like manner.
Claim 24
Dependent Claim
25 words
An imaging system according to claim 1, comprising: said receiving array transducers arranged in ring-like manner, and the transmitting array transducers arranged in linear manner.
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) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |