Electronically focused acoustic imaging system and method

Claim 3

A system in accordance with claim 1 wherein said delay line comprises an acoustic delay line.

Claim 4

A system in accordance with claim 2 wherein said signal generating means generates a delay line signal having a spatial extent along said acoustic delay line less than the spacing between taps on said delay line so that the delay line signal is applied to only one of the delay line taps at a time.

Claim 5

A system in accordance with claim 2 wherein said signal generating means generates a delay line signal having a spatial extent along said acoustic delay line such that the delay line signal is simultaneously applied to all the taps thereof.

Claim 6

A system in accordance with claim 4 in which said taps of said acoustic delay line are evenly spaced therealong so that there is a linear variation in phase of the delay line signal from tap to tap.

Claim 7

A system in accordance with claim 4 in which said taps of said acoustic delay line are non-uniformly spaced according to a linear variation along the acoustic delay line so that there is a quadratic variation in phase of the delay line signal from tap to tap.

Claim 10

A method in accordance with claim 7 wherein the delay line signal propagated down the delay line is an acoustic delay line signal and is formed to have a spatial extent along the delay line less than the spacing between taps on the delay line so that the delay line signal is sequentially applied to each of the delay line taps, one at a time, whereby a succession of the output signals are generated at the output terminal corresponding to and indicative of the presence of electrical transducer signals at the mixers.

Claim 11

A method in accordance with claim 7 wherein the delay line signal propagated down the delay line is an acoustic delay line signal and is formed to have a spatial extent along the delay line such that it simultaneously is applied to all the delay line taps, and including the step of applying a uniform plane wave energetic signal to the transducers so that a particular linear phase relationship is produced among the transducers which is coupled to the mixers, and including the further step of adjusting the frequency of the acoustic delay line signal applied to the delay line taps until a singLe large output signal is generated at the output terminal, the large output signal being indicative of phase correspondence between the transducer signal phase relationship and the phase relationship existing at the delay line taps for the acoustic delay line signal.

Claim 12

A method in accordance with claim 7 wherein the delay line signal propagated down the delay line is an acoustic delay line signal and is formed to have a spatial extent along the delay line such that it simultaneously is applied to all the delay line taps, and including the step of non-uniformly spacing the delay line taps with respect to each other in accordance with a linear relationship so that the phase relationship between the acoustic delay line signal as applied to the delay line taps varies quadratically, with the particular quadratic phase relationship varying with time as the delay line signal propagates down the delay line, with their being a large output at the output terminal whenever the quadratic phase relationship of the delay line signals at the delay line taps correspond to a quadratic phase relationship among the transducer signals.

Claim 13

A method in accordance with claim 7 wherein the delay line signal propagated down the delay line is an acoustic delay line signal and is formed to have spatial extent along the delay line such that it simultaneously is applied to all the delay line taps, and wherein the acoustic delay line signal has a varying frequency of the type omega omega 0 + Mu t, so that the phase relationship between the acoustic delay line signal as applied to the delay line tap varies quadratically, with the particular quadratic phase relationship varying with time as the delay line signal propagates down the delay line, with their being a large output at the output terminal whenever the quadratic phase relationship of the delay line signals at the delay line taps correspond to a quadratic phase relationship among the transducer signal.

Claim 14

An electronically focused lens useful for scanning an energetic image and generating electrical signals descriptive of the energetic images position in space or for generating a focused energetic image in response to electrical signals comprising an array of transducer elements of the type which can convert impinging energy into corresponding electrical transducer signals or which can convert electrical transducer signals into radiating energy, a plurality of mixers, one for each of the transducer elements, means coupling each of said transducer elements to its corresponding mixer, a delay line having a plurality of taps, one for each of said mixers, means coupling each of said delay line taps to a corresponding mixer, propagation means for propagating a delay line signal down said delay line with the delay line signal having a spatial extent along said delay line so that it simultaneously is applied to all the taps, with said propagation means producing a quadratic phase distribution in the delay line signal from tap to tap with the particular quadratic phase distribution changing with time as the delay line signal propagates down the delay line, and means coupling said mixers at a common terminal.

Claim 15

An electronically focused lens useful for scanning an energetic image and generating electrical signals descriptive of the energetic images position in space or for generating a focused energetic image in response to electrical signals comprising an array of transducer elements of the type which can convert impinging energy into corresponding electrical transducer signals or which can convert electrical transducer signals into radiating energy, a plurality of mixers, one for each of the transducer elements, means coupling each of said transducer elements to its corresponding mixer, a delay line having a plurality of taps, one for each of said mixers, means coupling each of said delay line taps to a corresponding mixer, propagation means for propagating a delay line signal down said delay line with the delay line signal having a spatial extent along said delay line so that it simultaneously is applied to all the taps, with said propagation means producing a quadratic phase distribution in the delay line signal from tap to tap with the particular quadratic phase distribution changing with time as the delay line signal propagates down the delay line, and means coupling said mixers at a common terminal.

Claim 16

An electronically focused lens in accordance with claim 12 wherein said delay line is an acoustic delay line and said propagation means includes means for coupling a constant frequency signal into said delay line and wherein said delay line taps are non-uniformly spaced with respect to each other in accordance with a linear relationship so that a quadratic phase distribution is produced in the delay line signal from tap to tap.

Claim 17

An electronically focused lens in accordance with claim 12 wherein said delay line is an acoustic delay line and said delay line taps are evenly spaced and said propagation means includes means for coupling a signal into said delay line having a frequency of the type omega omega 0 + Mu t so that a quadratic phase distribution is produced in the delay line Signal from tap to tap.

Claim 18

An electronically focused lens in accordance with claim 12 used for generating a focused energetic image in response to electrical signals and including a selectively energizable signal source coupled to said common terminal for said mixers whereby a transmitting signal can be coupled to all the mixers at a predetermined time with respect to the varying quadratic phase distribution of the delay line signals at the delay line taps so that the mixers generate electrical signals having a predetermined quadratic phase distribution from mixer to mixer which are respectively applied to said transducer elements for radiating energy focused at a particular point in space.

Claim 19

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a plurality of transducer elements of the type which convert impinging energy into corresponding electrical transducer signals, a plurality of mixers, one for each of the transducer elements, means coupling each of said transducer elements to its corresponding mixer, an acoustic delay line having a plurality of evenly spaced delay line taps, one for each of said mixers, means coupling each of said delay line taps to a corresponding mixer, propagation means for propagating a delay line signal down said acoustic delay line with the delay line signal having a varying frequency of the type omega omega o + Mu t and having a spatial extent along said acoustic delay line so that it simultaneously is applied to all the delay line taps whereby a quadratic phase distribution is produced in the delay line signal from tap to tap, with the quadratic phase distribution changing with time as the delay line signal propagates down the acoustic delay line, means commonly coupling the mixers at an output terminal so that signals appearing across the mixers are summed, with output signals being generated by the mixers at the sum and difference frequencies of the transducer signals and the signals applied to the mixers from the delay line taps, whereby a substantially large output at said output terminal is produced only when the quadratic phase distribution of the delay line signals applied to the mixers by the delay line taps corresponds to a quadratic phase distribution of the electrical transducer signals applied to the mixers from said transducer elements.

Claim 20

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a plurality of transducer elements of the type which convert impinging energy into corresponding electrical transducer signals, a plurality of mixers, one for each of the transducer elements, means coupling each of said transducer elements to its corresponding mixer, an acoustic delay line having a plurality of evenly spaced delay line taps, one for each of said mixers, means coupling each of said delay line taps to a corresponding mixer, propagation means for propagating a delay line signal down said acoustic delay line with the delay line signal having a varying frequency of the type omega omega o + Mu t and having a spatial extent along said acoustic delay line so that it simultaneously is applied to all the delay line taps whereby a quadratic phase distribution is produced in the delay line signal from tap to tap, with the quadratic phase distribution changing with time as the delay line signal propagates down the acoustic delay line, means commonly coupling the mixers at an output terminal so that signals appearing across the mixers are summed, with output signals being generated by the mixers at the sum and difference frequencies of the transducer signals and the signals applied to the mixers from the delay line taps, whereby a substantially large output at said output terminal is produced only when the quadratic phase distribution of the delay line signals applied to the mixers by the delay line taps corresponds to a quadratic phase distribution of the electrical transducer signals applied to the mixers from said transducer elements.

Claim 21

An electronically focused lens in accordance with claim 16 wherein the focal length of the lens is varied by varying the delay line signal which is of the form omega omega O + Mu t by varying the quantity Mu .

Claim 22

An electronically focused lens in accordance with claim 16 wherein said transducer elements are acoustic transducer elements.

Claim 23

An electronically focused lens in accordance with claim 16 including filter means connected to said output terminal for separating signals of a particular frequency range at said output terminal from other signals present at said output terminal.

Claim 24

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a transducer of the type which converts impinging energy into co-responding electrical transducer signals, said transducer extending along an x axis and a y axis so that it is two dimensional, said transducer having a first set of spaced parallel electrical contacts extending across the transducer parallel to the x axis and a second set of spaced parallel electrical contacts extending across the transducer parallel to the y axis, a first acoustic delay line having a plurality of spaced taps, means coupling each of the first acoustic delay line taps to one of the spaced parallel electrical contacts parallel to the x axis, a second acoustic delay line having a plurality of spaced taps, means coupling each of the second acoustic deLay line taps to one of the spaced parallel electrical contacts parallel to the y axis, means for propagating a first acoustic delay line signal down said first acoustic delay line, means for propagating a second acoustic delay line signal down said second acoustic delay line, both said first and second acoustic delay line signals having a spatial extent along their respective delay lines so as to be simultaneously present at all the taps of their respective delay lines, and both said first and second delay line signals having a frequency of the form omega omega O + Mu t so that a quadratic phase distribution is produced along the taps at their respective delay lines, one of said means coupling either each of the first acoustic delay line taps or the second acoustic delay line taps to the corresponding spaced parallel electrical contacts including a plurality of mixers, one for each of the delay line taps being so coupled, each of said first and second acoustic delay lines having means coupling the delay line taps thereon to a common terminal with the scanned output of the electronically focused lens appearing between the common terminals.

Claim 25

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a transducer of the type which converts impinging energy into co-responding electrical transducer signals, said transducer extending along an x axis and a y axis so that it is two dimensional, said transducer having a first set of spaced parallel electrical contacts extending across the transducer parallel to the x axis and a second set of spaced parallel electrical contacts extending across the transducer parallel to the y axis, a first acoustic delay line having a plurality of spaced taps, means coupling each of the first acoustic delay line taps to one of the spaced parallel electrical contacts parallel to the x axis, a second acoustic delay line having a plurality of spaced taps, means coupling each of the second acoustic deLay line taps to one of the spaced parallel electrical contacts parallel to the y axis, means for propagating a first acoustic delay line signal down said first acoustic delay line, means for propagating a second acoustic delay line signal down said second acoustic delay line, both said first and second acoustic delay line signals having a spatial extent along their respective delay lines so as to be simultaneously present at all the taps of their respective delay lines, and both said first and second delay line signals having a frequency of the form omega omega O + Mu t so that a quadratic phase distribution is produced along the taps at their respective delay lines, one of said means coupling either each of the first acoustic delay line taps or the second acoustic delay line taps to the corresponding spaced parallel electrical contacts including a plurality of mixers, one for each of the delay line taps being so coupled, each of said first and second acoustic delay lines having means coupling the delay line taps thereon to a common terminal with the scanned output of the electronically focused lens appearing between the common terminals.

Claim 26

An electronically focused lens in accordance with claim 20 wherein said transducer is an acoustic transducer.

Claim 27

An electronically focused lens in accordance with claim 20 wherein both said first and second acoustic delay line signals have a signal width greater than the length of their respective acoustic delay line so as to produce time varying quadratic phase distributions at the taps of the respective delay lines which sequentially correspond to quadratic phase distributions on said transducer due to energetic image sources at a succession of spatial points.

Claim 28

An electronically focused lens in accordance with claim 22 wherein both said first and second delay line signals are propagated down their respective delay lines at the same time so that a raster scan of the energetic image impinging on the transducer is generated.

Claim 29

An electronically focused lens in accordance with claim 23 wherein one of said first and second acoustic delay line signals is initially propagated at a time t t1 and other of said delay line signals is propagated at a later time t t1 + Tau .

Claim 30

An electronically focused lens in accordance with claim 24 including means for sequentially generating a plurality of pairs of first and second delay line signals and including means for sequentially varying the time relationship Tau between the sequentially generated pairs so that a two dimensional raster scan of the energetic image impinging upon said transducer is generated.

Claim 31

A method in accordance with claim 7 wherein the delay line signal propagated down the delay line is an acoustic delay line signal and is formed to have a spatial extent along the delay line such that it simultaneously is applied to all the delay line taps, and wherein the acoustic delay line signal has a varying frequency of the type given by two or more terms of the expansion

Claim 32

An electRonically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a two dimensional array of transducers of the type which convert impinging energy into corresponding electrical transducer signals, said two dimensional array comprising N contiguous one dimensional arrays each having the same number of discrete transducer elements, a plurality of sets of mixers, one for each of the N one dimensional arrays, each set of mixers comprising a plurality of mixers, one for each individual transducer element in the associated array with the output of each transducer element coupled across its corresponding mixer, a plurality of tapped delay lines, one for each of the N one dimensional arrays, each of said delay lines having a plurality of taps, one for each of the individual transducer elements in its associated array with each of said taps being coupled across the mixer for its individual transducer element, signal generating means for simultaneously applying a signal to all of the delay lines associated with the N one dimensional arrays, summing means associated with each of the sets of mixers for developing sum signals of the signals across the individual mixers in each of the sets; an additional distinct set of mixers having a plurality of mixers, one for each of the one dimensional transducer arrays, with the sum signal of the signals across the individual mixers in the set of mixers associated with each array being coupled across the corresponding mixers of said additional distinct set, an additional distinct tapped delay line having a plurality of taps, one for each of the mixers in said additional distinct set of mixers, with each of said taps being coupled across its corresponding mixer in said additional distinct set, additional signal generating means for applying a signal to said additional distinct delay line, and output means for summing the signals present at the plurality of mixers of said additional distinct set of mixers.

Claim 33

An electRonically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a two dimensional array of transducers of the type which convert impinging energy into corresponding electrical transducer signals, said two dimensional array comprising N contiguous one dimensional arrays each having the same number of discrete transducer elements, a plurality of sets of mixers, one for each of the N one dimensional arrays, each set of mixers comprising a plurality of mixers, one for each individual transducer element in the associated array with the output of each transducer element coupled across its corresponding mixer, a plurality of tapped delay lines, one for each of the N one dimensional arrays, each of said delay lines having a plurality of taps, one for each of the individual transducer elements in its associated array with each of said taps being coupled across the mixer for its individual transducer element, signal generating means for simultaneously applying a signal to all of the delay lines associated with the N one dimensional arrays, summing means associated with each of the sets of mixers for developing sum signals of the signals across the individual mixers in each of the sets; an additional distinct set of mixers having a plurality of mixers, one for each of the one dimensional transducer arrays, with the sum signal of the signals across the individual mixers in the set of mixers associated with each array being coupled across the corresponding mixers of said additional distinct set, an additional distinct tapped delay line having a plurality of taps, one for each of the mixers in said additional distinct set of mixers, with each of said taps being coupled across its corresponding mixer in said additional distinct set, additional signal generating means for applying a signal to said additional distinct delay line, and output means for summing the signals present at the plurality of mixers of said additional distinct set of mixers.

Claim 34

An electronically focused lens in accordance with claim 27 including timing means coupled to said signal generating means and said additional signal generating means for successively varying the time relationship between the signal generated by said signal generating means and the signal generated by said additional signal generating means.

Claim 35

An electronically focused lens in accordance with claim 27 wherein said tapped delay lines comprise acoustic delay lines and wherein the signals applied to said tapped delay lines have a frequency varied in such a manner that the phase distribution of the signals among the taps of said delay lines is of the same form as the phase distribution among the plurality of transducer elements.

Claim 36

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a twodimensional array of transducers of the type which convert impinging energy into corresponding electrical transducer signals, said two dimensional array comprising N contiguous one dimensional arrays each having the same number of discrete transducer elements, a plurality of sets of mixers, one for each of the N one dimensional arrays, each set of mixers comprising a plurality of mixers, one for each individual transducer element in the associated array with the output of each transducer element coupled across its corresponding mixer, a tapped delay line having a plurality of taps, one for each of the individual transducer elements in a one dimensional array, each of the delay line taps being coupled to one of the mixers in every one of the sets of mixers, signal generating means for applying a signal to said tapped delay line, summing means associated with each of the sets of mixers for developing sum signals of the signals across the individual mixers in each of the sets; an additional distinct set of mixers having a plurality of mixers, one For each of the one dimensional arrays, with the sum signal of the signals across the individual mixers in the set of mixers associated with each array being coupled across the corresponding mixer of said additional distinct set, an additional distinct tapped delay line having a plurality of taps, one for each of the mixers in said additional distinct set of mixers, with each of said taps being coupled across its corresponding mixer in said additional distinct set, additional signal generating means for applying a signal to said additional distinct delay line, and output means for summing the signals present at the plurality of mixers of said additional distinct set of mixers.

Claim 37

An electronically focused lens for scanning an energetic image and generating electrical signals descriptive of the spatial position of the energetic image comprising a twodimensional array of transducers of the type which convert impinging energy into corresponding electrical transducer signals, said two dimensional array comprising N contiguous one dimensional arrays each having the same number of discrete transducer elements, a plurality of sets of mixers, one for each of the N one dimensional arrays, each set of mixers comprising a plurality of mixers, one for each individual transducer element in the associated array with the output of each transducer element coupled across its corresponding mixer, a tapped delay line having a plurality of taps, one for each of the individual transducer elements in a one dimensional array, each of the delay line taps being coupled to one of the mixers in every one of the sets of mixers, signal generating means for applying a signal to said tapped delay line, summing means associated with each of the sets of mixers for developing sum signals of the signals across the individual mixers in each of the sets; an additional distinct set of mixers having a plurality of mixers, one For each of the one dimensional arrays, with the sum signal of the signals across the individual mixers in the set of mixers associated with each array being coupled across the corresponding mixer of said additional distinct set, an additional distinct tapped delay line having a plurality of taps, one for each of the mixers in said additional distinct set of mixers, with each of said taps being coupled across its corresponding mixer in said additional distinct set, additional signal generating means for applying a signal to said additional distinct delay line, and output means for summing the signals present at the plurality of mixers of said additional distinct set of mixers.

Claim 38

An electronically focused lens in accordance with claim 30 including timing means coupled to said signal generating means and said additional signal generating means for successively varying the time relationship between the signal generated by said signal generating means and the signal generated by said additional signal generating means.

Claim 39

An electronically focused lens in accordance with claim 30 wherein said tapped delay line and said additional tapped delay line comprise acoustic delay lines and wherein the signals applied to said tapped delay lines have a frequency varied in such a manner that the phase distribution of the signals among the taps of said delay lines is of the same form as the phase distribution among the plurality of transducer elements.

Claim 42

A method in accordance with claim 33 in which the signal propagated along the delay line has its frequency time varied in an approximately linear fashion from an initial frequency through a center frequency fo to a final frequency to perform a scan along a line of the object.

Claim 43

A method in accordance with claim 34 wherein only a relatively small proportion of the energy incident on the object is scattered by the object and including the step of reducing image information in the output signal corresponding to unscattered energy from the object by suppressing that portion of the signal propagated along the delay line which functions to image unscattered energy.

Claim 44

A method in accordance with claim 35 wherein a portion of the delay line signal is suppressed by reducing the amplitude of the delay line signal for a relatively narrow frequency band adjacent to both sides of and including the center frequency fo.

Claim 45

A method in accordance with claim 35 wherein a portion of the delay line signal is suppressed by reducing the amplitude of the delay line signal to zero for all frequencies between the center frequency fo and the final frequency and also for a narrow band of frequency adjacent the center frequency between the center frequency and the initial frequency.

Claim 46

A method in accordance with claim 35 wherein a portion of the deLay line signal is suppressed by phase shifting a narrow frequency band of the delay line signal adjacent to either side of and including the center frequency fo.

Claim 47

A method in accordance with claim 38 wherein the narrow frequency band is phase shifted by pi 12.

Claim 48

A method in accordance with claim 38 wherein the narrow frequency band is phase shifted by 3 pi /2.

Claim 49

A method in accordance with claim 34 wherein only a relatively small proportion of the energy incident on the object is scattered by the object and including the step of reducing image information in the output signal corresponding to unscattered energy from the object by mixing the output signal with a reference signal having the same frequency as the output signal so that the difference frequency resulting from the mixing comprises phase variation information corresponding to energy scattered by the object.

Claim 50

A method in accordance with claim 34 including the step of interlacing successive scans of lines of the object by modulating the illuminating energy for the object and correspondingly modulating the signal propagated along the delay line.

Claim 51

A method in accordance with claim 42 wherein the modulation of the signal propagated along the delay line and the illuminating energy comprises a corresponding step change in frequency for both from scan to scan.

Claim 52

A method in accordance with claim 42 wherein the modulation of the signal propagated along the delay line and the illuminating energy comprises corresponding changes in frequency of both during a scan.