CA1075354A - Multiple line of sight ultrasonic apparatus - Google Patents
Multiple line of sight ultrasonic apparatusInfo
- Publication number
- CA1075354A CA1075354A CA222,428A CA222428A CA1075354A CA 1075354 A CA1075354 A CA 1075354A CA 222428 A CA222428 A CA 222428A CA 1075354 A CA1075354 A CA 1075354A
- Authority
- CA
- Canada
- Prior art keywords
- echoes
- transducer elements
- region
- beams
- pulses
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
- G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
- G01S15/8909—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration
- G01S15/8915—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration using a transducer array
- G01S15/8918—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration using a transducer array the array being linear
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
- A61B8/4483—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device characterised by features of the ultrasound transducer
- A61B8/4494—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device characterised by features of the ultrasound transducer characterised by the arrangement of the transducer elements
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for the pulse-echo ultrasonic examination, parti-cularly in a medical diagnostic examination is comprised of a linear array of discrete transducer elements; means to energize at least one element of the array to transmit pulses of the ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object; and means for receiving echoes of the pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the region of the object, the means for receiving echoes comprising means to activate the transducer elements to receive echoes of each transmitted pulse along a plurality of the substantially parallel received beams.
An apparatus for the pulse-echo ultrasonic examination, parti-cularly in a medical diagnostic examination is comprised of a linear array of discrete transducer elements; means to energize at least one element of the array to transmit pulses of the ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object; and means for receiving echoes of the pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the region of the object, the means for receiving echoes comprising means to activate the transducer elements to receive echoes of each transmitted pulse along a plurality of the substantially parallel received beams.
Description
~ - ~ ~
753S~
This invention relates to the technique of ultra sonic echoscopy of objects and in particular to an extension of known techni~ues of ultrasonic echoscopy to provide more useful information concerning the examined objects. It is particularly, but not solely, directed to the more effective acquisition of data in medical diagnosis utilising this technique.
Ultrasonic echoscopy provides information about an examined object which may be displayed ln the form of an ultra-sonic echogram. Such an echogram consists of a display of acoustic impedance discontinuities or reflecting surfaces in the object. It is obtained by directing a short pulse of ultrasonic energy, typically in the 1-30 MHz frequency range, along a line called the beam axis into the examined object where any acoustic impedance discontinuities in the object reflect and return some of the energy along the same beam axis in the form of an echo. This echo is received, converted into i an electric signal and displayed as an echogram on a cathode ray oscilloscope, a film, a chart or the like.
The echogram may constitute either a one dimensional or a two dimensional representation and in both cases the in-formation is contained in the position and magnitude of the ": .
echo displayed. In a one dimenslonal display, the positlon along a base llne is used to indicate the distance to the reflecting surface whilst the magnitude of the echo is .. . .
., .
~LC375354 displayed, for example, as a deflection of the base line or as an intensity change. In a two dimensional display, the posi-tion along a base line is used to indicate the distance to the reflecting surface as in a one dimensional display, and the direction of the base line is used to represent the direction of propagation of the acoustic energy which is the beam axis.
The two dimensional display is obtained by changing this direc-tion of propagation of the acoustic energy and by instituting a similar but not necessarily identical movement of the base line of the display~ The magnitude of the echo is displayed -~ as for a one dimensional display; for example, as a deflection of the base line or as an intensity change.
The technique of ultrasonic echoscopy is used in medical diagnosis to obtain information about the anatomy of patients. The application of this technique is now widely in-vestigated and is described, for example, by D.E. Robinson in Proceeding of the Institution of Radio and Electronics ~ Engineers Australia, Vol.31, No.ll, pages 385-392, November, ; 1970: "The Application of Ultrasound in Medical Diagnosis".
As pointed out in this article, ultrasonic echoscopy may be used to produce displays resembling anatomical cross-sections . , which have proved clinically useful when the desired informa-tion concerns physical dimensions, shapes of organs or structures or the like. Ultrasonic echography has proved of particular value as a diagnostic aid in the abdomen and , . ,. . . ~ , .
.
~53S~
pregnant uterus, eye, breast, brain, lung, kidney, liver and heart, these being areas of soft tissue with little bone and air. In general, the technique is considered to complement other techniques to provide a more complete picture of the S patients condition, however particularly in pregnancies, ultra-sonic echoscopy may be useful in place of X-rays where the lat-ter may not give sufficient information or may be dangerous.
In medical use, a pulse of ultrasonic energy is transmitted into a patient in a known direction and echoes are received from reflecting surfaces within the body. The time delay between a transmitted pulse and the received echo depends o~
the distance from the transmitter to the reflecting surface and the distance information so obtained may be displayed in a suitable way for interpretation and clinical use as a one lS dimensional range reading or as a two dimensional cross section as previously described.
This known system suffers from a disadvantage due to the time required to obtain a cross-section. The cross-section ;~ is made up of a multiplicity of lines of information corres-ponding to each beam axis position at which a pulse was trans-mi~ted and echoes received. The time required to obtain each line of information is fixed by the depth of the tissues of interest and the velocity of propagation of sound in the tis-sues to be examined. For a particular area of interest neither of these parameters is under the control of the `'~' .
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-~7~3~i~
operator and they form a basic limitation on the time requixed to obtain an echogram. Consider as an example the visualisation of the heart, with a resolution of one millimetre over an examination area of ten centimetres square with a maximum depth below the sur-face of fifteen centimetres. For each cross-sectional picture, one hundred lines, or beam axis positions are required and the minimum time required for each position is two hundred microseconds, making a minimum time of twenty milliseconds. Thus the absolute maximum rate of obtaining complete pictures is fifty times per second, which may be only twenty five times per heart cycle and is insufficient for some diagnostic situations.
, ;~ It is a prlmary object of the present invention to provide an improved apparatus and method for the ultrasonic echoscopic examination whereby the time required to obtain each cross-sectional picture is reduced allowing the examination of moving structures with greater resolution and accuracy.
According to this invention, there is provided a linear array of discrete transducer elements; means to energize at least one element of the array to transmit pulses of ultrasonic energy into : ~ 20 the object in the form of a diverging beam of transmltted energy which ensonifies a region within the object; and means for receiv-ing echoes of the pulses of ultrasonic energy reflected by acous-tic impedance discontinuities within the region of the object, the means for receiving echoes comprising means to activate the trans-ducer elements to receive echoes of each transmitted pulse along a plurality of substantially parallel received beams.
In the apparatus of the present invention, it is preferred that the means for receiving echoes comprises a plurality of the txansducer elements and beam forming circuits arranged to provide a plurality of substantially parallel received beams with beam ,~, ~7535~
; axes corresponding to ~ach position required for a display line on a resulting intensity-modulated cross-sectional visualisation of the object; and the means for transmitting pulses comprises a num-ber of thP transducer elements less in number than the number of received beams and arranged to provide the diverging beam of trans-mitted energy to ensonify the region within the object covered by the plurality of received beams.
In another aspect, this invention provides a method of ultra-- sonic examination of an object comprising the steps of; transmitt-ing pulses of ultrasonic energy into the object by eneryizing at least one elementof a linear array of discrete transducer elements to form a diverging beam of transmitted energy which ensonifies a region within the object; and receiving echoes of the pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the object by activating a plu;rality of the transducer elements to receive echoes of each transmitted pulse along a plurality of ~ubstantially parallel received beams.
In order to display the echo information from each xeceived beam axis it is necessary to switch rapidly from one to the next many times during the period in which echoes are returning and to cause the deflected spot on the display to move likewise~ In this way a plurality of lines of echo data are rece~ved for each pulse transmitted and hence the absolute minimum time required for a cross-sectional picture is reduced, with a proportionally grea-ter reduction as the number of reviewed beam axis positions used for each transmitted pulse is increased. The apparatus of the present invention thus also includes display means including switch means for operating the display means to display echo in-- formation from the received beams.
` 30 ,., -~7~3S4 One embodiment of the invention is illustrated in the accompanying drawings in which:
Fig. 1 illustrates an arrangement of transducer elements which may be used in accordance with this invention;
- Fig. 2 shows the transmitted and received beams and the processing system utilising the principles of the present invention;
Fig. 3 illustrates a method of echo display in ac-cordance with this invention; and Fig. 4 illustrates the incorporation of the arrange- -ment of elements according to the present invention into an ultrasonic examination system.
The transducer array depicted in Fig. 1 consists of a plurality of active transducer elements, and by way of example thirty rectangular elements 1-30 are shown mounted on the flat rectangular strip 31. The width of each rectangular element is made equal to the actual spacing required between received beams. This will normally be sufficiently small with respect to the wavelength that the transmitted pulse beam diverges to ensonify the region above a number of receiver elements. For example, referring to Fig. 2, assume that element 5 is used to transmit as shown in Fig. 2 and its beam 32 ensonifies the region above elements 1 to 10. To obtain a narrow received beam a plurality of transducer elements may be used together with appropriate time delays being utilised to obtain focusing, for example using elements 1-5 a beam 33 may be formed with its axis above element 3; similarly using elements 2-6 a beam 34 , may be formed above element 4 and so on.
The display of Fig. 3 is generated by knowledge of - 30 the values x, y, ~x shown on the Flgure. The value x is given . .
., .
~L ,., 53S~
by the distance along the transducer to the centre of the transmitting transducer element. The value y is given by a constant multiplied by time and represents the depth into the examined object. The value ~x is the offset from the centre of the transmitting transducer element to the centre of the forrned receive beam. This display is more complex than displays obtained by the prior art methods because it comprises a display of a plurality of received beams concurrently. Thus the dis-played point must traverse a locus across all the received beams at a similar time delay of received echo before going onto greater time delays and thus greater ranges. The curve 73-75-80 represents the position of reflectors which give rise to echoes at constant time delay. Thus the path lengths 65-73-63, 65-75-65, 65-80-70 are all equal. The direct path length 65-75-65 given by 2y must equal any inclined path length such as 65-78-68 which is given by ~x) + (y-~y) + (y-~y); i.e., 2y=
, (~x) + (y-~y) + Y ~
From this relationship the required value for ~y can be found to be ;y = ~x Also shown in Fig. 2 is a scheme for processing the returned echo data in which beam forming circuits 43, 44, 45 produce signals representing echoes received along beams in beam axis positions 33, 34, 35 etc., respectively and these are fed to -the beam selector switch 51. During the time ~the echoes are returning, the beam selector 51 and the position of the dot on the display screen are switched rapidly to obtain and dis-~';
~C~753~ii4 play all the data. For instance Fig. 3 shows a diagram of a number of positions 73-80 on a number of beams from which echoes return at the same delay time, the said positions lying on a parabolic curve. Each of the said beams must be sampled and the results displayed during the time available until echoes are returning from the next set of .sample points 83-90. Therefore in this case a complete set of information on eight beam axis positions is obtained for one transmitted pulse. The procedure is then repeated using another transmitting element, such as 7.
An ultrasonic examination system incorporating this invention is shown in Fig. 4. In this system, timing is derived from the main clock 46 which is the most rapid timing interval in the system. A sample is taken from one of the received beams for each pulse of the main cloc~c. The received beam to be used is selected by the beam address counter 47 whose output goes to the beam selector switch 51. The output from the beam address counter 47 also provides information on the value of x for use in the x scan generator 48 and y scan generator 49.
; The master clock signal 46 is divided down by transmitter clock divider 50 and used to trigger the transmitter address counter 52 and the y time base generator 53. The transmitter address counter 52 output is fed to the transducer switch 60 which selects the appropriate transducer elements from transducer 30 for transmitting and receiving. The transmitting element is pulsed by transmitter 54 and receive elements are connected to beam forming circuits 43, 44, 45. The transmitter address counter 52 is also fed to the x deflection generator 55, the outpu'c x of which is added to theoutput ~x of X scan generator 48 in adder 56 and fed to the X deflection of the display 58.
The output y of the Y time base 53 is combined with the output 7' ,..,r,j~
~ ~ i ~0753~i4 of the beam address counter 47 in Y scan generator 49 according to the formula ~Y = 4y - and the output ~y of Y scan generator 49 combined with the output y of Y time base generator -53 in subtractor 57 and fed into the Y deflection of the display 58.
Signal processing and time gain control amplifier 59 is as well known in the current art and processes the signals from the beam selector switch 51 for the Z axis input of display The method may be modified in detail to optimise its performance. For instance a plurality of transducer elements may be employed on transmission to control the amount of diver-gence of the transmitted beam. The beam forming circuits 43, ~4, 45 etc., may include adding circuits and delay circuits to shape the received beam patternsO Such circuits are well known and reference is made to U.S. Patents 3,166,731 to Joy and 3,086,195 to Halliday which disclose electronic steering, focusing and reception of ultrasonics beams.
The method may also be extended in a straight forward fashion to operate on a three-dimensional basis, rather than , two-dimensionally as herein described. In this extension it is necessary to have a two-dimensional array of transducer elements and to receive along many lines of sight both within the plane of section before described and also in adjacent planes. In this case means are required to store the information from adjacent planes for subsequent display.
','' ',:
. ~, ! "
.
753S~
This invention relates to the technique of ultra sonic echoscopy of objects and in particular to an extension of known techni~ues of ultrasonic echoscopy to provide more useful information concerning the examined objects. It is particularly, but not solely, directed to the more effective acquisition of data in medical diagnosis utilising this technique.
Ultrasonic echoscopy provides information about an examined object which may be displayed ln the form of an ultra-sonic echogram. Such an echogram consists of a display of acoustic impedance discontinuities or reflecting surfaces in the object. It is obtained by directing a short pulse of ultrasonic energy, typically in the 1-30 MHz frequency range, along a line called the beam axis into the examined object where any acoustic impedance discontinuities in the object reflect and return some of the energy along the same beam axis in the form of an echo. This echo is received, converted into i an electric signal and displayed as an echogram on a cathode ray oscilloscope, a film, a chart or the like.
The echogram may constitute either a one dimensional or a two dimensional representation and in both cases the in-formation is contained in the position and magnitude of the ": .
echo displayed. In a one dimenslonal display, the positlon along a base llne is used to indicate the distance to the reflecting surface whilst the magnitude of the echo is .. . .
., .
~LC375354 displayed, for example, as a deflection of the base line or as an intensity change. In a two dimensional display, the posi-tion along a base line is used to indicate the distance to the reflecting surface as in a one dimensional display, and the direction of the base line is used to represent the direction of propagation of the acoustic energy which is the beam axis.
The two dimensional display is obtained by changing this direc-tion of propagation of the acoustic energy and by instituting a similar but not necessarily identical movement of the base line of the display~ The magnitude of the echo is displayed -~ as for a one dimensional display; for example, as a deflection of the base line or as an intensity change.
The technique of ultrasonic echoscopy is used in medical diagnosis to obtain information about the anatomy of patients. The application of this technique is now widely in-vestigated and is described, for example, by D.E. Robinson in Proceeding of the Institution of Radio and Electronics ~ Engineers Australia, Vol.31, No.ll, pages 385-392, November, ; 1970: "The Application of Ultrasound in Medical Diagnosis".
As pointed out in this article, ultrasonic echoscopy may be used to produce displays resembling anatomical cross-sections . , which have proved clinically useful when the desired informa-tion concerns physical dimensions, shapes of organs or structures or the like. Ultrasonic echography has proved of particular value as a diagnostic aid in the abdomen and , . ,. . . ~ , .
.
~53S~
pregnant uterus, eye, breast, brain, lung, kidney, liver and heart, these being areas of soft tissue with little bone and air. In general, the technique is considered to complement other techniques to provide a more complete picture of the S patients condition, however particularly in pregnancies, ultra-sonic echoscopy may be useful in place of X-rays where the lat-ter may not give sufficient information or may be dangerous.
In medical use, a pulse of ultrasonic energy is transmitted into a patient in a known direction and echoes are received from reflecting surfaces within the body. The time delay between a transmitted pulse and the received echo depends o~
the distance from the transmitter to the reflecting surface and the distance information so obtained may be displayed in a suitable way for interpretation and clinical use as a one lS dimensional range reading or as a two dimensional cross section as previously described.
This known system suffers from a disadvantage due to the time required to obtain a cross-section. The cross-section ;~ is made up of a multiplicity of lines of information corres-ponding to each beam axis position at which a pulse was trans-mi~ted and echoes received. The time required to obtain each line of information is fixed by the depth of the tissues of interest and the velocity of propagation of sound in the tis-sues to be examined. For a particular area of interest neither of these parameters is under the control of the `'~' .
'''' , .
-~7~3~i~
operator and they form a basic limitation on the time requixed to obtain an echogram. Consider as an example the visualisation of the heart, with a resolution of one millimetre over an examination area of ten centimetres square with a maximum depth below the sur-face of fifteen centimetres. For each cross-sectional picture, one hundred lines, or beam axis positions are required and the minimum time required for each position is two hundred microseconds, making a minimum time of twenty milliseconds. Thus the absolute maximum rate of obtaining complete pictures is fifty times per second, which may be only twenty five times per heart cycle and is insufficient for some diagnostic situations.
, ;~ It is a prlmary object of the present invention to provide an improved apparatus and method for the ultrasonic echoscopic examination whereby the time required to obtain each cross-sectional picture is reduced allowing the examination of moving structures with greater resolution and accuracy.
According to this invention, there is provided a linear array of discrete transducer elements; means to energize at least one element of the array to transmit pulses of ultrasonic energy into : ~ 20 the object in the form of a diverging beam of transmltted energy which ensonifies a region within the object; and means for receiv-ing echoes of the pulses of ultrasonic energy reflected by acous-tic impedance discontinuities within the region of the object, the means for receiving echoes comprising means to activate the trans-ducer elements to receive echoes of each transmitted pulse along a plurality of substantially parallel received beams.
In the apparatus of the present invention, it is preferred that the means for receiving echoes comprises a plurality of the txansducer elements and beam forming circuits arranged to provide a plurality of substantially parallel received beams with beam ,~, ~7535~
; axes corresponding to ~ach position required for a display line on a resulting intensity-modulated cross-sectional visualisation of the object; and the means for transmitting pulses comprises a num-ber of thP transducer elements less in number than the number of received beams and arranged to provide the diverging beam of trans-mitted energy to ensonify the region within the object covered by the plurality of received beams.
In another aspect, this invention provides a method of ultra-- sonic examination of an object comprising the steps of; transmitt-ing pulses of ultrasonic energy into the object by eneryizing at least one elementof a linear array of discrete transducer elements to form a diverging beam of transmitted energy which ensonifies a region within the object; and receiving echoes of the pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the object by activating a plu;rality of the transducer elements to receive echoes of each transmitted pulse along a plurality of ~ubstantially parallel received beams.
In order to display the echo information from each xeceived beam axis it is necessary to switch rapidly from one to the next many times during the period in which echoes are returning and to cause the deflected spot on the display to move likewise~ In this way a plurality of lines of echo data are rece~ved for each pulse transmitted and hence the absolute minimum time required for a cross-sectional picture is reduced, with a proportionally grea-ter reduction as the number of reviewed beam axis positions used for each transmitted pulse is increased. The apparatus of the present invention thus also includes display means including switch means for operating the display means to display echo in-- formation from the received beams.
` 30 ,., -~7~3S4 One embodiment of the invention is illustrated in the accompanying drawings in which:
Fig. 1 illustrates an arrangement of transducer elements which may be used in accordance with this invention;
- Fig. 2 shows the transmitted and received beams and the processing system utilising the principles of the present invention;
Fig. 3 illustrates a method of echo display in ac-cordance with this invention; and Fig. 4 illustrates the incorporation of the arrange- -ment of elements according to the present invention into an ultrasonic examination system.
The transducer array depicted in Fig. 1 consists of a plurality of active transducer elements, and by way of example thirty rectangular elements 1-30 are shown mounted on the flat rectangular strip 31. The width of each rectangular element is made equal to the actual spacing required between received beams. This will normally be sufficiently small with respect to the wavelength that the transmitted pulse beam diverges to ensonify the region above a number of receiver elements. For example, referring to Fig. 2, assume that element 5 is used to transmit as shown in Fig. 2 and its beam 32 ensonifies the region above elements 1 to 10. To obtain a narrow received beam a plurality of transducer elements may be used together with appropriate time delays being utilised to obtain focusing, for example using elements 1-5 a beam 33 may be formed with its axis above element 3; similarly using elements 2-6 a beam 34 , may be formed above element 4 and so on.
The display of Fig. 3 is generated by knowledge of - 30 the values x, y, ~x shown on the Flgure. The value x is given . .
., .
~L ,., 53S~
by the distance along the transducer to the centre of the transmitting transducer element. The value y is given by a constant multiplied by time and represents the depth into the examined object. The value ~x is the offset from the centre of the transmitting transducer element to the centre of the forrned receive beam. This display is more complex than displays obtained by the prior art methods because it comprises a display of a plurality of received beams concurrently. Thus the dis-played point must traverse a locus across all the received beams at a similar time delay of received echo before going onto greater time delays and thus greater ranges. The curve 73-75-80 represents the position of reflectors which give rise to echoes at constant time delay. Thus the path lengths 65-73-63, 65-75-65, 65-80-70 are all equal. The direct path length 65-75-65 given by 2y must equal any inclined path length such as 65-78-68 which is given by ~x) + (y-~y) + (y-~y); i.e., 2y=
, (~x) + (y-~y) + Y ~
From this relationship the required value for ~y can be found to be ;y = ~x Also shown in Fig. 2 is a scheme for processing the returned echo data in which beam forming circuits 43, 44, 45 produce signals representing echoes received along beams in beam axis positions 33, 34, 35 etc., respectively and these are fed to -the beam selector switch 51. During the time ~the echoes are returning, the beam selector 51 and the position of the dot on the display screen are switched rapidly to obtain and dis-~';
~C~753~ii4 play all the data. For instance Fig. 3 shows a diagram of a number of positions 73-80 on a number of beams from which echoes return at the same delay time, the said positions lying on a parabolic curve. Each of the said beams must be sampled and the results displayed during the time available until echoes are returning from the next set of .sample points 83-90. Therefore in this case a complete set of information on eight beam axis positions is obtained for one transmitted pulse. The procedure is then repeated using another transmitting element, such as 7.
An ultrasonic examination system incorporating this invention is shown in Fig. 4. In this system, timing is derived from the main clock 46 which is the most rapid timing interval in the system. A sample is taken from one of the received beams for each pulse of the main cloc~c. The received beam to be used is selected by the beam address counter 47 whose output goes to the beam selector switch 51. The output from the beam address counter 47 also provides information on the value of x for use in the x scan generator 48 and y scan generator 49.
; The master clock signal 46 is divided down by transmitter clock divider 50 and used to trigger the transmitter address counter 52 and the y time base generator 53. The transmitter address counter 52 output is fed to the transducer switch 60 which selects the appropriate transducer elements from transducer 30 for transmitting and receiving. The transmitting element is pulsed by transmitter 54 and receive elements are connected to beam forming circuits 43, 44, 45. The transmitter address counter 52 is also fed to the x deflection generator 55, the outpu'c x of which is added to theoutput ~x of X scan generator 48 in adder 56 and fed to the X deflection of the display 58.
The output y of the Y time base 53 is combined with the output 7' ,..,r,j~
~ ~ i ~0753~i4 of the beam address counter 47 in Y scan generator 49 according to the formula ~Y = 4y - and the output ~y of Y scan generator 49 combined with the output y of Y time base generator -53 in subtractor 57 and fed into the Y deflection of the display 58.
Signal processing and time gain control amplifier 59 is as well known in the current art and processes the signals from the beam selector switch 51 for the Z axis input of display The method may be modified in detail to optimise its performance. For instance a plurality of transducer elements may be employed on transmission to control the amount of diver-gence of the transmitted beam. The beam forming circuits 43, ~4, 45 etc., may include adding circuits and delay circuits to shape the received beam patternsO Such circuits are well known and reference is made to U.S. Patents 3,166,731 to Joy and 3,086,195 to Halliday which disclose electronic steering, focusing and reception of ultrasonics beams.
The method may also be extended in a straight forward fashion to operate on a three-dimensional basis, rather than , two-dimensionally as herein described. In this extension it is necessary to have a two-dimensional array of transducer elements and to receive along many lines of sight both within the plane of section before described and also in adjacent planes. In this case means are required to store the information from adjacent planes for subsequent display.
','' ',:
. ~, ! "
.
Claims (9)
1. Apparatus for the ultrasonic examination of an object comprising a linear array of discrete transducer elements;
means to energize at least one element of said array to transmit pulses of ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object;
means for receiving echoes of said pulses of ultra-sonic energy reflected by acoustic impedance discontinuities within said region of the object, said means for receiving echoes comprising means to activate said transducer elements to receive echoes of each transmitted pulse along a plurality of received beams; and means for concurrently displaying information based on the echoes received along each one of said plurality of beams.
means to energize at least one element of said array to transmit pulses of ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object;
means for receiving echoes of said pulses of ultra-sonic energy reflected by acoustic impedance discontinuities within said region of the object, said means for receiving echoes comprising means to activate said transducer elements to receive echoes of each transmitted pulse along a plurality of received beams; and means for concurrently displaying information based on the echoes received along each one of said plurality of beams.
2. Apparatus as claimed in claim 1, wherein:
said means for receiving echoes comprises a plurality of said transducer elements and beam forming circuits arranged to provide a plurality of substantially parallel received beams with beam axes corresponding to each position required for a display line on a resulting intensity-modulated cross-sectional visualisation of the object; and said means for transmitting pulses comprises a number of said transducer elements less in number than the number of received beams and arranged to provide said diverging beam of transmitted energy to ensonify the region within the object covered by the plurality of received beams.
said means for receiving echoes comprises a plurality of said transducer elements and beam forming circuits arranged to provide a plurality of substantially parallel received beams with beam axes corresponding to each position required for a display line on a resulting intensity-modulated cross-sectional visualisation of the object; and said means for transmitting pulses comprises a number of said transducer elements less in number than the number of received beams and arranged to provide said diverging beam of transmitted energy to ensonify the region within the object covered by the plurality of received beams.
3. Apparatus as claimed in claim 1, wherein said means for transmitting pulses comprises a single element of said array and said means for receiving echoes comprises a plurality of groups of elements of said array providing said plurality of substantially parallel received beams, and further including means for repeatedly sampling the echo information of each of said received beams during the period while echoes are being received.
4. Apparatus as claimed in claim 3, wherein said means for transmitting pulses comprises a plurality of said transducer elements.
5. Apparatus as claimed in claim 3, wherein the active faces of said transducer elements of said linear array are of rectangular shape.
6. Apparatus as claimed in claim 3, wherein said linear array of transducer elements is a planar array.
7. A method of ultrasonic examination of an object comprising the steps of:
transmitting pulses of ultrasonic energy into the object by energizing at least one element of a linear array of discrete transducer elements to form a diverging beam of trans-mitted energy which ensonifies a region within the object;
receiving echoes of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the object by activating a plurality of said transducer elements to receive echoes of each transmitted pulse along a plurality of received beams; and concurrently displaying information based on the echoes received along each one of said plurality of beams.
transmitting pulses of ultrasonic energy into the object by energizing at least one element of a linear array of discrete transducer elements to form a diverging beam of trans-mitted energy which ensonifies a region within the object;
receiving echoes of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within the object by activating a plurality of said transducer elements to receive echoes of each transmitted pulse along a plurality of received beams; and concurrently displaying information based on the echoes received along each one of said plurality of beams.
8. Apparatus for the ultrasonic examination of an object comprising:
a linear array of discrete transducer elements; means to energize at least one element of said array to transmit pulses of ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object;
means for receiving echoes of each of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within a respective region of predetermined width and depth of the object, said means for receiving echoes comprising means to activate said transducer elements to receive echoes of each transmitted pulse along a plurality of substantially parallel received beams; and means for substantially concurrently displaying in-formation based on the echoes received along each one of said plurality of beams, such that information representative of the acoustic impedance discontinuities within said region is dis-played within the time period following the transmission of a single pulse and preceding the transmission of the next pulse.
a linear array of discrete transducer elements; means to energize at least one element of said array to transmit pulses of ultrasonic energy into the object in the form of a diverging beam of transmitted energy which ensonifies a region within the object;
means for receiving echoes of each of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within a respective region of predetermined width and depth of the object, said means for receiving echoes comprising means to activate said transducer elements to receive echoes of each transmitted pulse along a plurality of substantially parallel received beams; and means for substantially concurrently displaying in-formation based on the echoes received along each one of said plurality of beams, such that information representative of the acoustic impedance discontinuities within said region is dis-played within the time period following the transmission of a single pulse and preceding the transmission of the next pulse.
9. A method of ultrasonic examination of an object comprising the steps of:
transmitting pulses of ultrasonic energy into the object by energizing at least one element of a linear array of discrete transducer elements to form a diverging beam of trans-mitted energy which ensonofies a region within the object, receiving echoes of each of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within a respective region of predetermined width and depth of the object by activating a plurality of said transducer elements to receive echoes of each transmitted pulse along a plurality of substan-tially parallel received beams, and substantially concurrently displaying information based on the echoes received along each one of said plurality of beams, such that information representa-tive of the acoustic impedance discontinuities within said region is displayed within the time period following the transmission of a single pulse and preceding the transmission of the next pulse.
transmitting pulses of ultrasonic energy into the object by energizing at least one element of a linear array of discrete transducer elements to form a diverging beam of trans-mitted energy which ensonofies a region within the object, receiving echoes of each of said pulses of ultrasonic energy reflected by acoustic impedance discontinuities within a respective region of predetermined width and depth of the object by activating a plurality of said transducer elements to receive echoes of each transmitted pulse along a plurality of substan-tially parallel received beams, and substantially concurrently displaying information based on the echoes received along each one of said plurality of beams, such that information representa-tive of the acoustic impedance discontinuities within said region is displayed within the time period following the transmission of a single pulse and preceding the transmission of the next pulse.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU694674 | 1974-03-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075354A true CA1075354A (en) | 1980-04-08 |
Family
ID=3697552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA222,428A Expired CA1075354A (en) | 1974-03-18 | 1975-03-18 | Multiple line of sight ultrasonic apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS50136087A (en) |
| AU (1) | AU7924075A (en) |
| CA (1) | CA1075354A (en) |
| DE (1) | DE2511709A1 (en) |
| GB (1) | GB1486066A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2412177A1 (en) * | 1977-12-16 | 1979-07-13 | Thomson Csf | HIGH SEPARATOR-POWERED ANTENNA SYSTEM |
-
1974
- 1974-03-18 AU AU79240/75A patent/AU7924075A/en not_active Expired
-
1975
- 1975-03-17 GB GB10944/75A patent/GB1486066A/en not_active Expired
- 1975-03-18 DE DE19752511709 patent/DE2511709A1/en not_active Withdrawn
- 1975-03-18 JP JP50032869A patent/JPS50136087A/ja active Pending
- 1975-03-18 CA CA222,428A patent/CA1075354A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS50136087A (en) | 1975-10-28 |
| AU7924075A (en) | 1976-09-23 |
| GB1486066A (en) | 1977-09-14 |
| DE2511709A1 (en) | 1975-10-02 |
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