CA1123504A - Ultrasonic scanner - Google Patents
Ultrasonic scannerInfo
- Publication number
- CA1123504A CA1123504A CA326,733A CA326733A CA1123504A CA 1123504 A CA1123504 A CA 1123504A CA 326733 A CA326733 A CA 326733A CA 1123504 A CA1123504 A CA 1123504A
- Authority
- CA
- Canada
- Prior art keywords
- signals
- ultrasonic
- predetermined
- path
- display
- 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
- G01S15/8993—Three dimensional imaging systems
-
- 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
- A61B8/42—Details of probe positioning or probe attachment to the patient
- A61B8/4209—Details of probe positioning or probe attachment to the patient by using holders, e.g. positioning frames
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/48—Diagnostic techniques
- A61B8/483—Diagnostic techniques involving the acquisition of a 3D volume of data
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/06—Visualisation of the interior, e.g. acoustic microscopy
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/06—Visualisation of the interior, e.g. acoustic microscopy
- G01N29/0609—Display arrangements, e.g. colour displays
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S128/00—Surgery
- Y10S128/916—Ultrasound 3-D imaging
Abstract
ULTRASONIC SCANNER
ABSTRACT OF THE DISCLOSURE
An ultrasonic pulse is directed into a body and electrical representations of pulse reflections from body interfaces along its path are generated. The ultrasonic signal path is scanned through a volume of the body and position signals indicative of the instantaneous path disposition are generated. The reflection signals are selectively gated in accordance with a predetermined function of the path disposition to provide a display selectively representing desired interfaces situated within a selected contoured portion of the volume. By varying the predetermined function, a specific desired interface surface may he displayed. Provisions for developing a three dimensional display of the selected surface are described.
ABSTRACT OF THE DISCLOSURE
An ultrasonic pulse is directed into a body and electrical representations of pulse reflections from body interfaces along its path are generated. The ultrasonic signal path is scanned through a volume of the body and position signals indicative of the instantaneous path disposition are generated. The reflection signals are selectively gated in accordance with a predetermined function of the path disposition to provide a display selectively representing desired interfaces situated within a selected contoured portion of the volume. By varying the predetermined function, a specific desired interface surface may he displayed. Provisions for developing a three dimensional display of the selected surface are described.
Description
ULTRASONIC SCANNER
SPE~IPICATION
. The present invention is directed to an ultra-- sonic scanning system ~or displaying an interface or surface located within a body, and particularly to such an ultrasonic scanner for use as a medical inst~ment.
Ultrasonic scanning systems of various types are well known in the prior art, ~or example, most prior art medical ultrasonic scanning systems ge~era].ly utiliæed may be classiC ed as A-type or B-~ype. In an A-type scanner, a rixed transducer pro~ides an ul~rasonic pulse 10 which is directed along a fixed path into the body. The time-of-return ~or reflections from internal orga~ic i~ter-faces are detected to provide an indication o~ the distance to such interfaces. In a B~type scanner, a pulsed ultra-sonic beam is swept in a single direction~ and, as in the lS A-~ype scanner, the successive distances (range~ to refl~cting organic inter~aces are determined by stan~ard lntervalometer m~thods. These B type scanners typically provide an indicia of the interface by, in e~fect, pl~tting the detected distances acJainsk the position of the beam 20 path. Various B-type scanners have included a real time display and have ef~ected scanning electrically, for example, by use of a phased transducer array.
In the present i~vention~ a volume is scanned in two dimensions and the three-di~ensional conkours of an ~.
, ~
~2351D4 interface surface are depicted on a two-dimensional display. Selective range gating, in accordance with a predetermined and/or variable function of the instantane-ous scan position, is utilized to select and contour the 5 volume actually depicted within the display. Such selective contouring eliminates "hash" or "clutter"
reflections from interfaces other than that of interest.
For example, in te~ms of a Cartesian coordinate system, assuming th~ Z axis to be pointed into the body and the 1~ scan performed in the X, Y plane, the gating circuits selectively pass reflections from interfaces located within a range of Z coordinates determined as a function of the X and Y position of the signal path.
It is noted that in the human body, most organs are roughly spherical in shape. Accordingly, it has been ~, found more conve~ient in a medical environment to operate in a polar e~&~ system, in effect, raster-scanning a solid angle within the body. The sc~nning operation is then described in terms of the angular disposition of the signal path defined by the angles ~ (with respect to the X
direction) and 3 ~with respect to the Y direction) and the radial distance R from the transducer. The gating ~unction is perrormed in the radial direction.
Such selective gating allows for a display show-25 ing onl~ the surface of a desired interface. Further, the~canning unction can be varied by an operator to fit the shape o~ a particular surface.
It has now been recognized by the present inventor that the maynitude (intensity) of th~ reflection 30 from an interface is a function of the angle of the beam with respect to a tangent plane or normal line to the re~lecting surface~ When the angle of incidence between the beam and a ~ormal line is small, the intensity of retro-reflection is high. Conver~ely, when the angle 35 ~etween the be~m and a normal lir~e is lar~e, the retro-reflection is of low intensity. Thus, after compensating for normal attenuation of the ultrasonic signals due to transmission within the body, the resultant varying intensity of reflection can be displayed in a raster scan manner to provide an actual molded or varying grey level "picture" of the surface in question.
This invention relates to an ultrasonic scanner system developing a two-dimensional display oE multi-valued signals representative of the varying in~ensities of ultrasonic signals reflected from three dimensional interfaces within a body, which intensities vary as a function of the angle of incidence of incident ultrasonic signals, said system comprising:
an ultrasonic transceiver for generating ultrasonic signals, directing said ultrasonic signals into said body along a path of predetermined disposition, and generating electrical output signals indicative of ultrasonic signals reflected back to said transceiver from said reflective interfaces;
said transceiver including scanning means for scanning said path of predetermined disposition and thus said ultrasonic signals through a predetermined volume within said body;
position means generating position signals indicative of the relative instantaneous dispositions of said ultrasonic signal path;
gating means 9 responsive to said position signals and to said transceiver output signals, for selectively passing only output signals representative of reflections from interEaces located within a substantial range of distances varying within predetermined minimum and maximum distances from said transceiver, which distanc~s at any given time are a function of the instantaneous relative disposition of said ultrasonic signal path thereby generating gated output signals representative of reflections from interfaces within a selected volume having a predetermined contour; and display means, responsive to said gated output signals and to said pOSitiOtl signals providing a two-dimensional display of multi-valued signals having more than 2 values and directly representative of and correlated to the corresponding varying intensities of ultrasonic signals reflected from the three-dimensional interface surfaces in said contourecl volume so as to dlrectly present a shaded two-dimensional depiction of said three-dimensional interface surfaces.
This invention also relates to an improvement in an ultrasonic scanning system of the type comprising (a) an ultrasonic transceiver for transmitting ultrasonic signals into a body along a given path direction and for developing electri.cal output signals representative of ultrasonic signals reflected back to the transceiver from interfaces located along said path, (b) gating means for passing only the electrical output signals representative of reflections from interfaces within a predetermined range of distances along said path, and (c) display means responsive to output signals passed by said gating means for providing indicia representative of said interfacesa the improvement wherein:
said transceiver includes means adapted for scanning said ultrasonic signals through a predetermined volume and said system further includes position means for generating position signals indicative of the instantaneous direction of said ultrasonic signal path; and said gating means includes range control means for varying said predetermined range of distances in accordance with a predetermined function of said position signals, such that the output signals passed thereby are representative of reflections from interfaces within a selected predetermined contoured portion of the scanned volume.
An exemplary embodiment of the present invention will hereinafter be described in conjunction with the following drawings, wherein like numerals denote like elements and:
FIGU~E 1 is a pictorial schematic of a transducer scanning mechanism and the solid angle of volume scanned thereby;
FIGURE 2 is a schematic block diagram of a scanner system in accordance -3a-*
with the present invention;
FI&URE 3 is a schematic diag-ram of a suitable gate control circuit;
FIGURE 4 is a schematic diagram of another suitable gating control circuit for effecting contour gating; and FIGURES 5a, 5b and 5c are exemplary plots versus time of various voltages Vl~ V and V3 associated with the circuit of FIGURE 4.
-3b-. . .
~35~
DETAILED DESCRIPTION_OF AN EXEMPLARY EMBODIMENT
Properly controlled phased arrays of fixed transducers may be used for scanning the ultrasonic beam.
On the other har.d, a mechanically scanned beam may also be employed~ The particular mechanism employed for the 5 scanning function per se is considered to be conventional, although one possible arrangement is depicted in the drawings.
Referring now to FIGURE 1, a con~entional ultra-sonic transducer 10 is mounted in a gimbal like mechanism 10 which provides two scanning degrees of freedom. The transducer can thus be scanned through an angle of 2~ with respPct to, for example, the X-direction and through an angle of 2~ with respect to, for example~ the Y-direction.
More specifically, transducer 10 is mounted in an inner 15 ring 14 having shaft-like projections 16 and 18. Projec-tions 16 and 18 are rotatably mounted in an outer ring 20, and respectively cooperate with a motor 22 of a conven-tional type and a sine~cosine generator 24. Sine/cosine generator 24 may be of any conventional type, but is 20 preferably of the type comprising a light and detector system cooperating with a template affixed to projection 18. The rota~ion of projection 18 causes a shaped aperture in the template to progressi~ely move into or out of a light passing relation~hip with the detector to ~5 produce a signal indicative of the sine or cosine of tha rotational angle of projection 18. Outer ring 20 has affixed thereto shaft projections 26 and 28, which are xotatably mounte~d in frame or housing 30. Projections 26 and 28 r respectively coopexate with a conventional 30 motor 32 and sine/cosine generator 34.
Motor 22 provides an oscillatory motion in ~ of txansducer 10, while motor 32.~ sweeps transducer 10 in ar to provide a raster scan of a solid angle in the body.
The scanning mechanism is suitably handheld and manually 35 positioned againsk the body~ although mechanical position~
.
.
~3~3~
ing apparatus can, of coursel be u~ilized. It should be appreciated that the sweeping action of transducer 10 in ~ could be manually effected by the operator rather than by use of motor 32. A water bag or gel 36 may be used to 5 reduce attenuation in air gaps otherwise present between the transducer and body.
Referring now to ~IGURE 2, motors 22 and 32 are driven by suitable conventional motor drive circuitry 38, cooperating with suita~le conv ntional timing logic 40~
10 Cosine ~ and cosine ~ sianals from sine/cosine generators 23 and 34 may be utilized as feedback signals, in accor-dance with conventional techniqu~s, for motor drive circuitry 38 and are also ~pplied to timing logic 40.
Timing logic 40 may be special hardwired logic 15 or a conventional programmed mi roprocessor or mini-computer. Responsive to the position signals~ that is, the cosine ~ and the cosine ~ signals, timing logic 40 operates to generate trigger pulses to a con~entional pulser 42 such as Metrotek MP ~0 type pulser. Signals 20 from pulser 42 are applied, through a conventional T-coupler or cir~ulator 44 to transducer 10 to effect genera~ion of an ultrasonic pulse~ Timing logic 40 generates a first trigger pulse to pulser 42 when trans-ducer 10 is in the far upper portion of the scan as 25 determined by the position signals, and thereafter provides trigger signals in accordance with a prede~er-mined an~ular displacement within the scan. The time period between pulses is chosen in accordance with the depth of the selected interface within the body so as to 30 permit reception of corresponding re~lected signals priox to generation of the nexk pulse.
As is well known in the art, the distance to a xeflecting interface i.s directly proportional to time required for the roundtrip of a pulse between the txans-35 ducer and the interface. More ~pecifically, the rangedistance R is equal to one-half the roundtrip transit period multiplied by the velocity of sound in the body~
, ~2^3~
~owever, a por~ion of the ultrasonic pulse is reflected back to the transducer from each interfa~e along its path. Reflections from the interfaces othex than the interface of interest (hash) are thus â potential source 5 of confusion in the display. In order to provide selectivity between the various interfa~es, a range gating system is utilized. In general, range gating systems se are well known in the radar and sonar arts. Reflec~
tions from the various interfaces are received by trans-10 ducer 10 and applied through T-coupler 44 and a variable gain amplifier 4h to a gating device 48 such as an FET~
Gate 48 is selectively rendered conductive for a predeter-mined second time period after a first time period which corresponds to the roundtrip transit time for a selected 15 location on the near side of the area of interest. The gate is thus opened for a time period corresponding to a range R to ~ ~ ~R o~ distances from the transducerO Re-flections from interfaces outside o~ that range are blocked to insure a display o only those interfaces 20 located within the selected range.
Gate device 48 is controlled by a gate control circuit S0. A simple delay circuit for providing a range gate corresponding to a spherical surface section is shown in FIGURE 3. This circuit (50a) comprises two 25 serially connected one-shots 52 and 54~ suitably Texas Instruments SN 74123 type chips~ One-shot 52 is triggered by the timing logic trigger pulse used in generating the u`ltrasonic pulse. The duration of the output signal of one-shot 52 is made to correspond to the roundtrip 30 distance between transducer 10 aIld the near side of ~he selected area of interest. The negative_going transition at the output of one-shot 52 is uti~iæed to trigger one-shot 54, which produces a pulse having a duration corxesponding to the thickne~s ~R of the selected volume.
35 The xespective durations of the one-shot output signals may ~e suitably controlled by the operator through poten-tiometexs 56 and 58.
Such a gate control circuit 50a will, during the course of the scan, gate reflection signals corres-ponding to a portion ~R of the solid angle such as shown in FIGURE lo Referring again to ~IGURE 2, the gated output signals are applied to a display means 6S. Display 68 comprises a scan converter 70 and conventional CRT display 72. Scan converter 70 operates to reeord the gated data at the scan rate of the ultrasonic system, and then to 10 apply such data to CRT display 72 at rates compatible with the CRT raster scan.
In accordance with one aspect of the present invention, the grey level or beam intensity of the CRT
display is controlled in accordance with the amplitude 15 of the gated signals to provide a molded or three dimensional pictorial depiction of interface surfaces wiihin ~he selected portion of the scanned volume. The retro-reflection of the ultrasonic signals from the reflecting inter~ace are proportional to the angle of 20 incidence between the path of the ultrasonic pulse and a normal to the surface. Where the angle between the beam path and normal is small, the in~ensity of r~otro-refle~tiOn is high. When such angle of incidenc~ is large, the retro-reflection i5 of low intensity. Thus, by control-25 li~g beam intensity in the CRT in accordance with theintensity of retro reflection, an actual grey level "picture" of the in~erface surface is developed. The varying grey level depiction shades the otherwise two dimensional displa~ so as to provide a three~dimen~ional 30 visual effect much like the usual photograph of thr~e-dimensional articles.
~ owever, the ultrasonic signal naturally decreases exponentially in int~n~ity as it passes *hrough body tissue due to the usual attenuation. Accordingly, 35 it is ~esirable to provide compensation for such attenua-tion. Such compensat-on is accomplished in the p~eferred - emhodiment by varia~le gain amplifier 46. Variable gain i ~3~
amplifier 46 may be a Motorola MC 1350 video IF amplifier which provides a predetermined gain reduction characteris-tic. The gain decreases from a maximum by amounts in accordance with a predetermined function beginning at an 5 input voltage determined by a reference voltage applied to the amplifier. A voltage Vr~ indicative of the desired displacement R o~ the selected vol~me is utilized as the reference voltage. The gated signal or data corresponding thereto is stoxed in locations in the 10 scan converter in accordance with the angles ~ and a .
The scan converter generally stores the information in accordance with a Cartesian coordinate system (X, Y) wherein the X and Y position~ for the data ~re determined as follows:
lS X = S Tan ~
L = S/Cos ~ istance from center of raster scan area to a given data point) Y = L Tan u = S ~an Cos ~
The value 5 is an arhitrary value acl~usted such that the 20 display on the CRT s~reen, fxom left: to right, will be near the edge o~ the screen when the transducer is in its maximum angle ~. For example, if the maximum angle for the transd~cer is +20~, ~hen ~he gain of the scan con~er-ter is adiusted such that the maximum value of X is equal 2S to S Tan 20~ Such an adjustment will provide 1 to 1 c~rrespondence between .the transmitted ultrasonic pulses and the poin~s on the scan converter ~and, ul~imately, the CRT) raster. It should ~e appreciated that the roundtrip txansit time of the ultransonic pulses is 30 negligible with respect to the mechanical scanning o the transducer 10 and the display raster scanning~
It should be appreciated that the data can be digitized and stored in a high speed mass data storage or.
m~mory rather than.in a scan converter. The data can then 35 be read out of storage through an appropriate D~A convexter and displayed on the CRT.
It should also be appreciated, however~ that when the ln~erface surface to be observed does no~ readily fit into a spherical section, the simple gate control circuit 40a may not be sufficient to adequately block unwanted xeflections. ~or example, if spherical section 5 60 is considered to be a concave section and the surface of the interface to be observed were convex~ the thickness of spherical section 60 would have to be relatively thick in order to encompass the interface surface. Accordingly, the display could be cluttered with indicia of interfaces 10 other than the interface of interest but within the gated range. It is therefore desirable to contour the range gate in accoxdance with the particular surface to be viewed.
Assuming the range gate to begin at a distanc2 R from the transducer, the range gate can be contoured 15 by varying R during the couxse of the scan. Noting that the distance R at any instance during tha scan can be expressed as a function of the cosines of ~ and ~, gate control circuit 50 can be made, in accordance with one aspect of the present invention, to contour the range sate 20 by activating gate devices at times corresponding to differing distances ~ in ac~ordance with the relative disposition of the path of the ultrasonic pulses within the scanned volume.
A suitable circuit 50b ~or g~nerating control 25 signals to gate 48 to effect a ranye gate that can be .
adjusted by the operator to foll~w a concave, ~lat, or convex surface~either the X or Y d.ir~ction is shown in FIGURE 4~ The respective cosine ~ignals are applied to respective amplifiers Al and A2, toge~her with voltages 30 to adjust the respective output voltages V1 and V2 of amplifiers Al and A2 to provide a zer~ voltage at ~~ An example of a typi,cal cosine ~ voltage function ~ver ~20~
~can is shown in ~IGURE 5~a), along with the correspQnding adjusted voltage Vl. Voltages V~ and V2 are respectively 35 applied to one input terminal of suitable multiplier modules Ml and M2, such as Burr Brown BB 4295 type multipliers. Multipliers Ml and M2 also receive at the other input terminals, X contour voltages and Y contour voltages respectively. The X and Y contour ~oltages generated at levels between a positive maximum and negative minimum in accordance with potentiometers P3 and P4. The 5 output voltages Vx and Vy of multipliers Ml and M2 are respectively equal to the product of the input signals divided by 10. Vx and Vy, together with voltage Vr developed by potentiometer P5 (indicative of a desired R displacement)~ are summed by summing amplifier A3. The 10 resulting voltage V3 is thus a curve, varying in accordance with ~ and ~.
The paxameters of the curve are controlled by the operator by adjusting potentiometers P3, P4 and P5.
For example, potentiometers P3 and P4 are respectiv~ly 15 connected between positive and negative voltage sources.
By varying the potentiometer from a center position, the respective contour voltages can be made positive or negative to provide either concave sr convex curvature.
As the magnitude of contour voltage becomes larger, the 20 ~oltage waveform will become more curved with the cosine of the respective associated angle. Such a con~our ad-justment of Vx is illustrated i~ FIGURE 5b.
The R displacement voltage Vr corresponds Lo the estimated distance to the inter~ace of interest. As
SPE~IPICATION
. The present invention is directed to an ultra-- sonic scanning system ~or displaying an interface or surface located within a body, and particularly to such an ultrasonic scanner for use as a medical inst~ment.
Ultrasonic scanning systems of various types are well known in the prior art, ~or example, most prior art medical ultrasonic scanning systems ge~era].ly utiliæed may be classiC ed as A-type or B-~ype. In an A-type scanner, a rixed transducer pro~ides an ul~rasonic pulse 10 which is directed along a fixed path into the body. The time-of-return ~or reflections from internal orga~ic i~ter-faces are detected to provide an indication o~ the distance to such interfaces. In a B~type scanner, a pulsed ultra-sonic beam is swept in a single direction~ and, as in the lS A-~ype scanner, the successive distances (range~ to refl~cting organic inter~aces are determined by stan~ard lntervalometer m~thods. These B type scanners typically provide an indicia of the interface by, in e~fect, pl~tting the detected distances acJainsk the position of the beam 20 path. Various B-type scanners have included a real time display and have ef~ected scanning electrically, for example, by use of a phased transducer array.
In the present i~vention~ a volume is scanned in two dimensions and the three-di~ensional conkours of an ~.
, ~
~2351D4 interface surface are depicted on a two-dimensional display. Selective range gating, in accordance with a predetermined and/or variable function of the instantane-ous scan position, is utilized to select and contour the 5 volume actually depicted within the display. Such selective contouring eliminates "hash" or "clutter"
reflections from interfaces other than that of interest.
For example, in te~ms of a Cartesian coordinate system, assuming th~ Z axis to be pointed into the body and the 1~ scan performed in the X, Y plane, the gating circuits selectively pass reflections from interfaces located within a range of Z coordinates determined as a function of the X and Y position of the signal path.
It is noted that in the human body, most organs are roughly spherical in shape. Accordingly, it has been ~, found more conve~ient in a medical environment to operate in a polar e~&~ system, in effect, raster-scanning a solid angle within the body. The sc~nning operation is then described in terms of the angular disposition of the signal path defined by the angles ~ (with respect to the X
direction) and 3 ~with respect to the Y direction) and the radial distance R from the transducer. The gating ~unction is perrormed in the radial direction.
Such selective gating allows for a display show-25 ing onl~ the surface of a desired interface. Further, the~canning unction can be varied by an operator to fit the shape o~ a particular surface.
It has now been recognized by the present inventor that the maynitude (intensity) of th~ reflection 30 from an interface is a function of the angle of the beam with respect to a tangent plane or normal line to the re~lecting surface~ When the angle of incidence between the beam and a ~ormal line is small, the intensity of retro-reflection is high. Conver~ely, when the angle 35 ~etween the be~m and a normal lir~e is lar~e, the retro-reflection is of low intensity. Thus, after compensating for normal attenuation of the ultrasonic signals due to transmission within the body, the resultant varying intensity of reflection can be displayed in a raster scan manner to provide an actual molded or varying grey level "picture" of the surface in question.
This invention relates to an ultrasonic scanner system developing a two-dimensional display oE multi-valued signals representative of the varying in~ensities of ultrasonic signals reflected from three dimensional interfaces within a body, which intensities vary as a function of the angle of incidence of incident ultrasonic signals, said system comprising:
an ultrasonic transceiver for generating ultrasonic signals, directing said ultrasonic signals into said body along a path of predetermined disposition, and generating electrical output signals indicative of ultrasonic signals reflected back to said transceiver from said reflective interfaces;
said transceiver including scanning means for scanning said path of predetermined disposition and thus said ultrasonic signals through a predetermined volume within said body;
position means generating position signals indicative of the relative instantaneous dispositions of said ultrasonic signal path;
gating means 9 responsive to said position signals and to said transceiver output signals, for selectively passing only output signals representative of reflections from interEaces located within a substantial range of distances varying within predetermined minimum and maximum distances from said transceiver, which distanc~s at any given time are a function of the instantaneous relative disposition of said ultrasonic signal path thereby generating gated output signals representative of reflections from interfaces within a selected volume having a predetermined contour; and display means, responsive to said gated output signals and to said pOSitiOtl signals providing a two-dimensional display of multi-valued signals having more than 2 values and directly representative of and correlated to the corresponding varying intensities of ultrasonic signals reflected from the three-dimensional interface surfaces in said contourecl volume so as to dlrectly present a shaded two-dimensional depiction of said three-dimensional interface surfaces.
This invention also relates to an improvement in an ultrasonic scanning system of the type comprising (a) an ultrasonic transceiver for transmitting ultrasonic signals into a body along a given path direction and for developing electri.cal output signals representative of ultrasonic signals reflected back to the transceiver from interfaces located along said path, (b) gating means for passing only the electrical output signals representative of reflections from interfaces within a predetermined range of distances along said path, and (c) display means responsive to output signals passed by said gating means for providing indicia representative of said interfacesa the improvement wherein:
said transceiver includes means adapted for scanning said ultrasonic signals through a predetermined volume and said system further includes position means for generating position signals indicative of the instantaneous direction of said ultrasonic signal path; and said gating means includes range control means for varying said predetermined range of distances in accordance with a predetermined function of said position signals, such that the output signals passed thereby are representative of reflections from interfaces within a selected predetermined contoured portion of the scanned volume.
An exemplary embodiment of the present invention will hereinafter be described in conjunction with the following drawings, wherein like numerals denote like elements and:
FIGU~E 1 is a pictorial schematic of a transducer scanning mechanism and the solid angle of volume scanned thereby;
FIGURE 2 is a schematic block diagram of a scanner system in accordance -3a-*
with the present invention;
FI&URE 3 is a schematic diag-ram of a suitable gate control circuit;
FIGURE 4 is a schematic diagram of another suitable gating control circuit for effecting contour gating; and FIGURES 5a, 5b and 5c are exemplary plots versus time of various voltages Vl~ V and V3 associated with the circuit of FIGURE 4.
-3b-. . .
~35~
DETAILED DESCRIPTION_OF AN EXEMPLARY EMBODIMENT
Properly controlled phased arrays of fixed transducers may be used for scanning the ultrasonic beam.
On the other har.d, a mechanically scanned beam may also be employed~ The particular mechanism employed for the 5 scanning function per se is considered to be conventional, although one possible arrangement is depicted in the drawings.
Referring now to FIGURE 1, a con~entional ultra-sonic transducer 10 is mounted in a gimbal like mechanism 10 which provides two scanning degrees of freedom. The transducer can thus be scanned through an angle of 2~ with respPct to, for example, the X-direction and through an angle of 2~ with respect to, for example~ the Y-direction.
More specifically, transducer 10 is mounted in an inner 15 ring 14 having shaft-like projections 16 and 18. Projec-tions 16 and 18 are rotatably mounted in an outer ring 20, and respectively cooperate with a motor 22 of a conven-tional type and a sine~cosine generator 24. Sine/cosine generator 24 may be of any conventional type, but is 20 preferably of the type comprising a light and detector system cooperating with a template affixed to projection 18. The rota~ion of projection 18 causes a shaped aperture in the template to progressi~ely move into or out of a light passing relation~hip with the detector to ~5 produce a signal indicative of the sine or cosine of tha rotational angle of projection 18. Outer ring 20 has affixed thereto shaft projections 26 and 28, which are xotatably mounte~d in frame or housing 30. Projections 26 and 28 r respectively coopexate with a conventional 30 motor 32 and sine/cosine generator 34.
Motor 22 provides an oscillatory motion in ~ of txansducer 10, while motor 32.~ sweeps transducer 10 in ar to provide a raster scan of a solid angle in the body.
The scanning mechanism is suitably handheld and manually 35 positioned againsk the body~ although mechanical position~
.
.
~3~3~
ing apparatus can, of coursel be u~ilized. It should be appreciated that the sweeping action of transducer 10 in ~ could be manually effected by the operator rather than by use of motor 32. A water bag or gel 36 may be used to 5 reduce attenuation in air gaps otherwise present between the transducer and body.
Referring now to ~IGURE 2, motors 22 and 32 are driven by suitable conventional motor drive circuitry 38, cooperating with suita~le conv ntional timing logic 40~
10 Cosine ~ and cosine ~ sianals from sine/cosine generators 23 and 34 may be utilized as feedback signals, in accor-dance with conventional techniqu~s, for motor drive circuitry 38 and are also ~pplied to timing logic 40.
Timing logic 40 may be special hardwired logic 15 or a conventional programmed mi roprocessor or mini-computer. Responsive to the position signals~ that is, the cosine ~ and the cosine ~ signals, timing logic 40 operates to generate trigger pulses to a con~entional pulser 42 such as Metrotek MP ~0 type pulser. Signals 20 from pulser 42 are applied, through a conventional T-coupler or cir~ulator 44 to transducer 10 to effect genera~ion of an ultrasonic pulse~ Timing logic 40 generates a first trigger pulse to pulser 42 when trans-ducer 10 is in the far upper portion of the scan as 25 determined by the position signals, and thereafter provides trigger signals in accordance with a prede~er-mined an~ular displacement within the scan. The time period between pulses is chosen in accordance with the depth of the selected interface within the body so as to 30 permit reception of corresponding re~lected signals priox to generation of the nexk pulse.
As is well known in the art, the distance to a xeflecting interface i.s directly proportional to time required for the roundtrip of a pulse between the txans-35 ducer and the interface. More ~pecifically, the rangedistance R is equal to one-half the roundtrip transit period multiplied by the velocity of sound in the body~
, ~2^3~
~owever, a por~ion of the ultrasonic pulse is reflected back to the transducer from each interfa~e along its path. Reflections from the interfaces othex than the interface of interest (hash) are thus â potential source 5 of confusion in the display. In order to provide selectivity between the various interfa~es, a range gating system is utilized. In general, range gating systems se are well known in the radar and sonar arts. Reflec~
tions from the various interfaces are received by trans-10 ducer 10 and applied through T-coupler 44 and a variable gain amplifier 4h to a gating device 48 such as an FET~
Gate 48 is selectively rendered conductive for a predeter-mined second time period after a first time period which corresponds to the roundtrip transit time for a selected 15 location on the near side of the area of interest. The gate is thus opened for a time period corresponding to a range R to ~ ~ ~R o~ distances from the transducerO Re-flections from interfaces outside o~ that range are blocked to insure a display o only those interfaces 20 located within the selected range.
Gate device 48 is controlled by a gate control circuit S0. A simple delay circuit for providing a range gate corresponding to a spherical surface section is shown in FIGURE 3. This circuit (50a) comprises two 25 serially connected one-shots 52 and 54~ suitably Texas Instruments SN 74123 type chips~ One-shot 52 is triggered by the timing logic trigger pulse used in generating the u`ltrasonic pulse. The duration of the output signal of one-shot 52 is made to correspond to the roundtrip 30 distance between transducer 10 aIld the near side of ~he selected area of interest. The negative_going transition at the output of one-shot 52 is uti~iæed to trigger one-shot 54, which produces a pulse having a duration corxesponding to the thickne~s ~R of the selected volume.
35 The xespective durations of the one-shot output signals may ~e suitably controlled by the operator through poten-tiometexs 56 and 58.
Such a gate control circuit 50a will, during the course of the scan, gate reflection signals corres-ponding to a portion ~R of the solid angle such as shown in FIGURE lo Referring again to ~IGURE 2, the gated output signals are applied to a display means 6S. Display 68 comprises a scan converter 70 and conventional CRT display 72. Scan converter 70 operates to reeord the gated data at the scan rate of the ultrasonic system, and then to 10 apply such data to CRT display 72 at rates compatible with the CRT raster scan.
In accordance with one aspect of the present invention, the grey level or beam intensity of the CRT
display is controlled in accordance with the amplitude 15 of the gated signals to provide a molded or three dimensional pictorial depiction of interface surfaces wiihin ~he selected portion of the scanned volume. The retro-reflection of the ultrasonic signals from the reflecting inter~ace are proportional to the angle of 20 incidence between the path of the ultrasonic pulse and a normal to the surface. Where the angle between the beam path and normal is small, the in~ensity of r~otro-refle~tiOn is high. When such angle of incidenc~ is large, the retro-reflection i5 of low intensity. Thus, by control-25 li~g beam intensity in the CRT in accordance with theintensity of retro reflection, an actual grey level "picture" of the in~erface surface is developed. The varying grey level depiction shades the otherwise two dimensional displa~ so as to provide a three~dimen~ional 30 visual effect much like the usual photograph of thr~e-dimensional articles.
~ owever, the ultrasonic signal naturally decreases exponentially in int~n~ity as it passes *hrough body tissue due to the usual attenuation. Accordingly, 35 it is ~esirable to provide compensation for such attenua-tion. Such compensat-on is accomplished in the p~eferred - emhodiment by varia~le gain amplifier 46. Variable gain i ~3~
amplifier 46 may be a Motorola MC 1350 video IF amplifier which provides a predetermined gain reduction characteris-tic. The gain decreases from a maximum by amounts in accordance with a predetermined function beginning at an 5 input voltage determined by a reference voltage applied to the amplifier. A voltage Vr~ indicative of the desired displacement R o~ the selected vol~me is utilized as the reference voltage. The gated signal or data corresponding thereto is stoxed in locations in the 10 scan converter in accordance with the angles ~ and a .
The scan converter generally stores the information in accordance with a Cartesian coordinate system (X, Y) wherein the X and Y position~ for the data ~re determined as follows:
lS X = S Tan ~
L = S/Cos ~ istance from center of raster scan area to a given data point) Y = L Tan u = S ~an Cos ~
The value 5 is an arhitrary value acl~usted such that the 20 display on the CRT s~reen, fxom left: to right, will be near the edge o~ the screen when the transducer is in its maximum angle ~. For example, if the maximum angle for the transd~cer is +20~, ~hen ~he gain of the scan con~er-ter is adiusted such that the maximum value of X is equal 2S to S Tan 20~ Such an adjustment will provide 1 to 1 c~rrespondence between .the transmitted ultrasonic pulses and the poin~s on the scan converter ~and, ul~imately, the CRT) raster. It should ~e appreciated that the roundtrip txansit time of the ultransonic pulses is 30 negligible with respect to the mechanical scanning o the transducer 10 and the display raster scanning~
It should be appreciated that the data can be digitized and stored in a high speed mass data storage or.
m~mory rather than.in a scan converter. The data can then 35 be read out of storage through an appropriate D~A convexter and displayed on the CRT.
It should also be appreciated, however~ that when the ln~erface surface to be observed does no~ readily fit into a spherical section, the simple gate control circuit 40a may not be sufficient to adequately block unwanted xeflections. ~or example, if spherical section 5 60 is considered to be a concave section and the surface of the interface to be observed were convex~ the thickness of spherical section 60 would have to be relatively thick in order to encompass the interface surface. Accordingly, the display could be cluttered with indicia of interfaces 10 other than the interface of interest but within the gated range. It is therefore desirable to contour the range gate in accoxdance with the particular surface to be viewed.
Assuming the range gate to begin at a distanc2 R from the transducer, the range gate can be contoured 15 by varying R during the couxse of the scan. Noting that the distance R at any instance during tha scan can be expressed as a function of the cosines of ~ and ~, gate control circuit 50 can be made, in accordance with one aspect of the present invention, to contour the range sate 20 by activating gate devices at times corresponding to differing distances ~ in ac~ordance with the relative disposition of the path of the ultrasonic pulses within the scanned volume.
A suitable circuit 50b ~or g~nerating control 25 signals to gate 48 to effect a ranye gate that can be .
adjusted by the operator to foll~w a concave, ~lat, or convex surface~either the X or Y d.ir~ction is shown in FIGURE 4~ The respective cosine ~ignals are applied to respective amplifiers Al and A2, toge~her with voltages 30 to adjust the respective output voltages V1 and V2 of amplifiers Al and A2 to provide a zer~ voltage at ~~ An example of a typi,cal cosine ~ voltage function ~ver ~20~
~can is shown in ~IGURE 5~a), along with the correspQnding adjusted voltage Vl. Voltages V~ and V2 are respectively 35 applied to one input terminal of suitable multiplier modules Ml and M2, such as Burr Brown BB 4295 type multipliers. Multipliers Ml and M2 also receive at the other input terminals, X contour voltages and Y contour voltages respectively. The X and Y contour ~oltages generated at levels between a positive maximum and negative minimum in accordance with potentiometers P3 and P4. The 5 output voltages Vx and Vy of multipliers Ml and M2 are respectively equal to the product of the input signals divided by 10. Vx and Vy, together with voltage Vr developed by potentiometer P5 (indicative of a desired R displacement)~ are summed by summing amplifier A3. The 10 resulting voltage V3 is thus a curve, varying in accordance with ~ and ~.
The paxameters of the curve are controlled by the operator by adjusting potentiometers P3, P4 and P5.
For example, potentiometers P3 and P4 are respectiv~ly 15 connected between positive and negative voltage sources.
By varying the potentiometer from a center position, the respective contour voltages can be made positive or negative to provide either concave sr convex curvature.
As the magnitude of contour voltage becomes larger, the 20 ~oltage waveform will become more curved with the cosine of the respective associated angle. Such a con~our ad-justment of Vx is illustrated i~ FIGURE 5b.
The R displacement voltage Vr corresponds Lo the estimated distance to the inter~ace of interest. As
2~ illustrated in FIGURE 5c, the R displacement voltage V~, in effect, sets the DC level of voltage V3 where ~ and axe both zero, i.e., the maxi~num or minimum of V3.
The voltage V3 is applied to an integrator 62 comprising an amplifier A4, resistor R18 and capacitor C1O
30 the output of integrator 62, V4, is given by the following equation: V 1 ~3 4 Cl J R18 dt.
However, the controlled integration period is very short such that V3 varies oniy slightly during the ~5 integration and can be considered a constant. Accordingly, V4 may be expressed:
c~
v 4 ClR t where t is the integration timeO
Voltage V4 is applied to a suitable comparator 64, which also receives a variable reference voltage V6 5 generated at potentiometer P6. The voltage V~ i~ set in accordance with the approximate distance of the interface to b2 viewed. Potentiometer P6 can, if desixed, be replaced by a switch to select various approximate starting ranges, such as 2cm, 4cm, etc. Comparator 64 genexates a transis-10 tor or pulse when V4 xeaches the level of V6, to triggera one-shot 66, and thereby produce a range gate pulse~
The duration of the one-shot output pulse is controlled by a potentiometer P7.
The in~egration period is initiated in 15 accordance with the trigger pulses f.rom timi~g logic 40O
The trigger pulses are applied to a :Elip flop F~l to set the flip flop and render nonconductive a switching device Ql shunted across integrating capacitor Cl. Flip flop FFl is reset in accordance with the firing of one-shot 20 66 to end the integration period, di,scharge capacitor C
and inhibit integrator 62 until the next trig~er pulse.
Thus, the length of time it takes integrator A~ to reach threshold level V6 is generally in accordance with the equation, Ax ~ B~ t C where Ax i~ the x contour voltage, 25 By is the y contour voltage and C is Vr.
Thus, circuit 50b effects conduction in gate device 48 for varying time period~, corresponding to varying range gates, in accordance with the scanning motion of the transducer~
It should be appreciated that circuit 50b is only one example of many suitable contour gating control circuits. Suitably programmed digita~ circuits could also be used. In practice, the predetermined function provided by the co~tour gating control circuit is shosen in 35 acco.rdance with the gene:ral expected shape of the objects ~o be viewed.
It should be noted that while the various conductors shown interconnecting the elements of the drawings are shown in single lines, they are not shown in a limiting sense and may comprise plural connections as 5 is understood in the art. Further, it will be understood that the above description of one exemplary embodiment G~
the present invention is for illustrative purposes only.
The invention is not limited to the specific form shown, and many modifications may be made in the specific design 10 and arrangement of elements without departing from the spirit or scope of the invention a~ defined in the appended claims.
The voltage V3 is applied to an integrator 62 comprising an amplifier A4, resistor R18 and capacitor C1O
30 the output of integrator 62, V4, is given by the following equation: V 1 ~3 4 Cl J R18 dt.
However, the controlled integration period is very short such that V3 varies oniy slightly during the ~5 integration and can be considered a constant. Accordingly, V4 may be expressed:
c~
v 4 ClR t where t is the integration timeO
Voltage V4 is applied to a suitable comparator 64, which also receives a variable reference voltage V6 5 generated at potentiometer P6. The voltage V~ i~ set in accordance with the approximate distance of the interface to b2 viewed. Potentiometer P6 can, if desixed, be replaced by a switch to select various approximate starting ranges, such as 2cm, 4cm, etc. Comparator 64 genexates a transis-10 tor or pulse when V4 xeaches the level of V6, to triggera one-shot 66, and thereby produce a range gate pulse~
The duration of the one-shot output pulse is controlled by a potentiometer P7.
The in~egration period is initiated in 15 accordance with the trigger pulses f.rom timi~g logic 40O
The trigger pulses are applied to a :Elip flop F~l to set the flip flop and render nonconductive a switching device Ql shunted across integrating capacitor Cl. Flip flop FFl is reset in accordance with the firing of one-shot 20 66 to end the integration period, di,scharge capacitor C
and inhibit integrator 62 until the next trig~er pulse.
Thus, the length of time it takes integrator A~ to reach threshold level V6 is generally in accordance with the equation, Ax ~ B~ t C where Ax i~ the x contour voltage, 25 By is the y contour voltage and C is Vr.
Thus, circuit 50b effects conduction in gate device 48 for varying time period~, corresponding to varying range gates, in accordance with the scanning motion of the transducer~
It should be appreciated that circuit 50b is only one example of many suitable contour gating control circuits. Suitably programmed digita~ circuits could also be used. In practice, the predetermined function provided by the co~tour gating control circuit is shosen in 35 acco.rdance with the gene:ral expected shape of the objects ~o be viewed.
It should be noted that while the various conductors shown interconnecting the elements of the drawings are shown in single lines, they are not shown in a limiting sense and may comprise plural connections as 5 is understood in the art. Further, it will be understood that the above description of one exemplary embodiment G~
the present invention is for illustrative purposes only.
The invention is not limited to the specific form shown, and many modifications may be made in the specific design 10 and arrangement of elements without departing from the spirit or scope of the invention a~ defined in the appended claims.
Claims (25)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An ultrasonic scanner system developing a two-dimensional display of multi-valued signals representative of the varying intensities of ultrasonic signals reflected from three dimensional interfaces within a body, which intensities vary as a function of the angle of incidence of incident ultrasonic signals, said system comprising:
an ultrasonic transceiver for generating ultrasonic signals, directing said ultrasonic signals into said body along a path of predetermined disposition, and generating electrical output signals indicative of ultrasonic signals reflected back to said transceiver from said reflective interfaces;
said transceiver including scanning means for scanning said path of predetermined disposition and thus said ultrasonic signals through a predetermined volume within said body;
position means generating position signals indicative of the relative instantaneous dispositions of said ultrasonic signal path;
gating means, responsive to said position signals and to said transceiver output signals, for selectively passing only output signals representative of reflections from interfaces located within a substantial range of distances varying within predetermined minimum and maximum distances from said transceiver, which distances at any given time are a function of the instantaneous relative disposition of said ultrasonic signal path thereby generating gated output signals representative of reflections from interfaces within a selected volume having a predetermined contour; and display means, responsive to said gated output signals and to said position signals providing a two-dimensional display of multi-valued signals having more than 2 values and directly representative of and correlated to the corresponding varying intensities of ultrasonic signals reflected from the three-dimensional interface surfaces in said contoured volume so as to directly present a shaded two-dimensional depiction of said three-dimensional interface surfaces.
an ultrasonic transceiver for generating ultrasonic signals, directing said ultrasonic signals into said body along a path of predetermined disposition, and generating electrical output signals indicative of ultrasonic signals reflected back to said transceiver from said reflective interfaces;
said transceiver including scanning means for scanning said path of predetermined disposition and thus said ultrasonic signals through a predetermined volume within said body;
position means generating position signals indicative of the relative instantaneous dispositions of said ultrasonic signal path;
gating means, responsive to said position signals and to said transceiver output signals, for selectively passing only output signals representative of reflections from interfaces located within a substantial range of distances varying within predetermined minimum and maximum distances from said transceiver, which distances at any given time are a function of the instantaneous relative disposition of said ultrasonic signal path thereby generating gated output signals representative of reflections from interfaces within a selected volume having a predetermined contour; and display means, responsive to said gated output signals and to said position signals providing a two-dimensional display of multi-valued signals having more than 2 values and directly representative of and correlated to the corresponding varying intensities of ultrasonic signals reflected from the three-dimensional interface surfaces in said contoured volume so as to directly present a shaded two-dimensional depiction of said three-dimensional interface surfaces.
2. The system of claim 1 wherein said display means includes a cathode ray tube responsive to said position signals in deflecting an electron beam onto a display screen and responsive to said gated signals in modulating the intensity of said electron beam.
3. The system of claims 1 or 2 further including compensation means, connected between said transceiver and said display means, which adjusts the level of said output signals in accordance with the approximate distance traveled by the ultrasonic signals within said body thereby compensating for the attenuation of said ultrasonic signals in said body.
4. The system of claim 1, wherein said gating means comprises:
a gate device for selectively passing said output signals in response to a control signal;
first timing means generating a first timing signal representing the end of a first time period occurring after transmission of an ultrasonic signal into said body, said first time period varying in accordance with a predetermined function of said position signals;
and second timing means for generating a second timing signal of predetermined duration in response to said first timing signal, said second timing signal being applied to said gate device as said control signal.
a gate device for selectively passing said output signals in response to a control signal;
first timing means generating a first timing signal representing the end of a first time period occurring after transmission of an ultrasonic signal into said body, said first time period varying in accordance with a predetermined function of said position signals;
and second timing means for generating a second timing signal of predetermined duration in response to said first timing signal, said second timing signal being applied to said gate device as said control signal.
5. The system of claim 4 further comprising range control means for selectively varying said predeter-mined function whereby said contoured volume can be changed to accommodate a particular desired interface surface.
6. The system of claim 5 further including compensation means, connected between said transceiver and said display means, which adjusts the level of said output signals in accordance with the approximate distance traveled by the ultrasonic signals within said body thereby compensating for the attenuation of said ultra-sonic signals in said body.
7. In an ultrasonic scanning system of the type comprising (a) an ultrasonic transceiver for transmitting ultrasonic signals into a body along a given path direction and for developing electrical output signals representative of ultrasonic signals reflected back to the transceiver from interfaces located along said path, (b) gating means for passing only the electrical output signals representative of reflections from interfaces within a predetermined range of distances along said path, and (c) display means responsive to output signals passed by said gating means for providing indicia representative of said interfaces, the improvement wherein:
said transceiver includes means adapted for scanning said ultrasonic signals through a predetermined volume and said system further includes position means for generating position signals indicative of the instantaneous direction of said ultrasonic signal path; and said gating means includes range control means for varying said predetermined range of distances in accordance with a predetermined function of said position signals, such that the output signals passed thereby are representative of reflections from interfaces within a selected predetermined contoured portion of the scanned volume.
said transceiver includes means adapted for scanning said ultrasonic signals through a predetermined volume and said system further includes position means for generating position signals indicative of the instantaneous direction of said ultrasonic signal path; and said gating means includes range control means for varying said predetermined range of distances in accordance with a predetermined function of said position signals, such that the output signals passed thereby are representative of reflections from interfaces within a selected predetermined contoured portion of the scanned volume.
8. The improved ultrasonic scanning system of claim 7 wherein said display means comprises means for generating two-dimensional pictorial representations of three-dimensional interface surfaces contained within said contoured portion of the scanned volume by displaying multi-valued visual signals representing the varying intensities of ultrasonic signals reflected from respectively corresponding portions of said surfaces.
9. The improved ultrasonic scanning system of claims 7 or 8 wherein said gating means further comprises means for selectively varying said predetermined function whereby said contoured volumed portion can be varied to accommodate a particular desired interface surface in said body.
10. The improved ultrasonic scanning system of claims 1, 7 or 8 further including means for automatically effecting said scanning.
11. In an ultrasonic scanning system of the type comprising (a) an ultrasonic transducer for transmitting ultrasonic signals into a body along a given path direction and developing electrical output signals representative of ultrasonic signals reflected back to the transducer from interfaces located along said path, (b) gating means for passing only the electrical output signals representative of reflections from interfaces within a predetermined range of distances along said path, and (c) display means responsive to output signals passed by said gating means for providing indicia representative of said interfaces, the improvement wherein:
said transducer includes means adapted to scan said ultrasonic signals through a predetermined volume encompassing a predetermined interface and said system further includes position means for providing position signals indicative of the instantaneous disposition of said ultrasonic signal path within the predetermined volume;
said gating means includes means connected to receive said position signals and to change said predetermined range as a function thereof whereby only reflections from interfaces having corresponding contours are passed through said gating means; and compensation means which compensates for attenuation of said ultrasonic signals such that the amplitude of said gated signals is substantially independent of the distance to said predetermined interface whereby the signal amplitude of output signals passed by said gating means is indicative of the relative angle between the reflecting predetermined interface and said ultrasonic signal path;
and said display means includes means for generating multi-valued display signals respectively corresponding to the varying amplitude of output signals passed by said gating means, and means responsive to said position signals for visually displaying said multi-valued display signals on a two-dimensional display at locations thereon respectively corresponding to the disposition of the ultrasonic signal path which caused such display signal to occur.
said transducer includes means adapted to scan said ultrasonic signals through a predetermined volume encompassing a predetermined interface and said system further includes position means for providing position signals indicative of the instantaneous disposition of said ultrasonic signal path within the predetermined volume;
said gating means includes means connected to receive said position signals and to change said predetermined range as a function thereof whereby only reflections from interfaces having corresponding contours are passed through said gating means; and compensation means which compensates for attenuation of said ultrasonic signals such that the amplitude of said gated signals is substantially independent of the distance to said predetermined interface whereby the signal amplitude of output signals passed by said gating means is indicative of the relative angle between the reflecting predetermined interface and said ultrasonic signal path;
and said display means includes means for generating multi-valued display signals respectively corresponding to the varying amplitude of output signals passed by said gating means, and means responsive to said position signals for visually displaying said multi-valued display signals on a two-dimensional display at locations thereon respectively corresponding to the disposition of the ultrasonic signal path which caused such display signal to occur.
12. The improved ultrasonic scanning system of claim 11 wherein said display means generates shaded two-dimensional pictorial-like representations of the three-dimensional interface surfaces within the selected contoured volumed portion.
13. The system of claims 11 or 12 wherein said display means comprises a cathode ray tube with its electron beam deflected in response to said posi-tion signals and the intensity of its electron beam varied in response to the amplitude of output signals passed by said gating means.
14. In the system of claim 11, the further improvement wherein:
said gating means includes range means for varying said predeter-mined range of distances in accordance with a predetermined function of said position signals such that output signals passed by the gating means repre-sent reflections from interfaces within a variably selected portion of said scanned volume.
said gating means includes range means for varying said predeter-mined range of distances in accordance with a predetermined function of said position signals such that output signals passed by the gating means repre-sent reflections from interfaces within a variably selected portion of said scanned volume.
15. The system of claims 12 and 14 wherein said display means com-prises a cathode ray tube with its electron beam deflected in response to said position signals and the intensity of its electron beam varied in re-sponse to the amplitude of output signals passed by said gating means.
16. The system of claims 12 and 14 wherein said gating means further comprises means for selectively varying said predetermined function whereby the contour of the selected volume can be varied to accommodate a particular desired interface surface.
17. The system of claims 11 or 12 further including means for automatically effecting said scanning.
18. Apparatus for developing a visual represen-tation of a predetermined internal surface in a body, said apparatus comprising:
means for transmitting an ultrasonic signal into said body along a predetermined path and for receiving ultrasonic signals retro-reflected back from surfaces encountered in said body along said path;
said means for transmitting being adapted for scanning said path throughout a predetermined volume with-in said body and encompassing said predetermined surface;
gating means responsive to a control signal for selectively passing signals derived from said retro-reflected ultrasonic signals to produce a gated signal representative of reflections from surfaces encountered within a predetermined range of distances located a specific distance from said means for transmitting and receiving;
means for generating position signals indica-tive of the instantaneous disposition of the ultrasonic signal path within said volume;
means for generating said control signal in accordance with a predetermined function of the position signals such that said gated signal represents reflec-tions from said surfaces within a contoured portion of the scanned volume, said contoured portion being approximately fitted to the expected shape of said particular internal surface; and display means responsive to said gated signal for providing a visual representation of said predeter-mined internal surfaces.
means for transmitting an ultrasonic signal into said body along a predetermined path and for receiving ultrasonic signals retro-reflected back from surfaces encountered in said body along said path;
said means for transmitting being adapted for scanning said path throughout a predetermined volume with-in said body and encompassing said predetermined surface;
gating means responsive to a control signal for selectively passing signals derived from said retro-reflected ultrasonic signals to produce a gated signal representative of reflections from surfaces encountered within a predetermined range of distances located a specific distance from said means for transmitting and receiving;
means for generating position signals indica-tive of the instantaneous disposition of the ultrasonic signal path within said volume;
means for generating said control signal in accordance with a predetermined function of the position signals such that said gated signal represents reflec-tions from said surfaces within a contoured portion of the scanned volume, said contoured portion being approximately fitted to the expected shape of said particular internal surface; and display means responsive to said gated signal for providing a visual representation of said predeter-mined internal surfaces.
19. The apparatus of claim 18 further including:
means for varying said predetermined function whereby said contoured portion can be approximately matched to a particular surface.
means for varying said predetermined function whereby said contoured portion can be approximately matched to a particular surface.
20. The apparatus of claim 18 wherein said display means comprises means compensating for attenuation of said ultrasonic signals in accordance with the approximate distance traveled by the ultrasonic signals;
means generating multi-valued display signals indicative of the varying amplitude of the compensated and gated signals representing retro-reflected ultrasonic signals; and means relating the multi-valued display signals to the position signals and producing a visual display depicting the three-dimensional inter-nal surface being scanned.
means generating multi-valued display signals indicative of the varying amplitude of the compensated and gated signals representing retro-reflected ultrasonic signals; and means relating the multi-valued display signals to the position signals and producing a visual display depicting the three-dimensional inter-nal surface being scanned.
21. The apparatus of claims 19 and 20 wherein said display means com-prises a cathode ray tube connected to deflect an electron beam in response to said position signals and to vary the intensity of such electron beam in response to said multi-valued display signals.
22. A method providing a visual representation of a selected internal surface in a body comprising the steps of:
directing an ultrasonic signal into said body along a predeter-mined path and generating electrical reflection signals indicative of ultra-sonic signals retro-reflected back from internal surfaces encountered along said path;
scanning said path through a predetermined volume of said body encompassing said selected internal surface;
generating position signals indicative of the instantaneous dis-position of said ultrasonic signal path within said volume;
selectively passing said reflection signals through a gate to generate a gated signal representing retro-reflections from internal surfaces within a predetermined range of distances;
varying said predetermined range of distances in accordance with a predetermined function of the position signals such that said gated signal represents retro-reflections from selected internal surfaces within a select-ed contoured portion of said scanned volume; and generating and displaying visual indicia of said selected inter-nal surfaces within said selected contoured portion from said gated signal.
directing an ultrasonic signal into said body along a predeter-mined path and generating electrical reflection signals indicative of ultra-sonic signals retro-reflected back from internal surfaces encountered along said path;
scanning said path through a predetermined volume of said body encompassing said selected internal surface;
generating position signals indicative of the instantaneous dis-position of said ultrasonic signal path within said volume;
selectively passing said reflection signals through a gate to generate a gated signal representing retro-reflections from internal surfaces within a predetermined range of distances;
varying said predetermined range of distances in accordance with a predetermined function of the position signals such that said gated signal represents retro-reflections from selected internal surfaces within a select-ed contoured portion of said scanned volume; and generating and displaying visual indicia of said selected inter-nal surfaces within said selected contoured portion from said gated signal.
23. A method as in claim 22 further comprising the step of compensat-ing for the approximate distance traveled by the ultrasonic signals so that the selectively passed reflection signals are substantially independent of such distance.
24. A method as in claim 22 wherein said visual indicia are poten-tially multi-valued for any given location on a two-dimensional visual dis-play and where the value of such indicia for any given location-is a function of the amplitude of retro-reflected ultrasonic signals emanating from a re-spectively corresponding location on the selected internal surface.
25. A method as in claims 23 and 24 wherein said predetermined func-tion is selectively varied so as to change the contoured volume to accommo-date a particular desired interface surface.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/902,740 US4271706A (en) | 1978-05-03 | 1978-05-03 | Ultrasonic scanner |
| US902,740 | 1986-09-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1123504A true CA1123504A (en) | 1982-05-11 |
Family
ID=25416339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA326,733A Expired CA1123504A (en) | 1978-05-03 | 1979-05-01 | Ultrasonic scanner |
Country Status (14)
| Country | Link |
|---|---|
| US (1) | US4271706A (en) |
| JP (1) | JPS54144786A (en) |
| BE (1) | BE875980A (en) |
| CA (1) | CA1123504A (en) |
| DE (1) | DE2911957B2 (en) |
| DK (1) | DK152154B (en) |
| ES (1) | ES480125A0 (en) |
| FR (1) | FR2425081A1 (en) |
| GB (1) | GB2020428B (en) |
| IE (1) | IE48106B1 (en) |
| IT (1) | IT1113927B (en) |
| LU (1) | LU81205A1 (en) |
| MX (1) | MX146784A (en) |
| NL (1) | NL187035C (en) |
Families Citing this family (55)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2063474B (en) * | 1979-10-24 | 1984-06-06 | Olympus Optical Co | Coeliac cavity ultrasonic diagnosis apparatus |
| US4485819A (en) * | 1980-01-21 | 1984-12-04 | Wolfgang Igl | Mechanical accessory for commercially available compound apparatuses for echo mammography |
| US4399704A (en) * | 1981-06-03 | 1983-08-23 | Technicare Corporation | Ultrasound scanner having compound transceiver for multiple optimal focus |
| US5262628A (en) * | 1982-01-25 | 1993-11-16 | Symbol Technologies, Inc. | Narrow-bodied, single- and twin-windowed portable laser scanning head for reading bar code symbols |
| DE3224453A1 (en) * | 1982-06-30 | 1984-01-05 | Siemens AG, 1000 Berlin und 8000 München | ULTRASONIC TOMOGRAPHER |
| DE3224412A1 (en) * | 1982-06-30 | 1984-01-05 | Siemens AG, 1000 Berlin und 8000 München | ULTRASONIC TOMOGRAPHER |
| US4454764A (en) * | 1982-09-03 | 1984-06-19 | Medtronic, Inc. | Roller-ball ultrasonic imaging module |
| US4476873A (en) * | 1982-09-03 | 1984-10-16 | Medtronic, Inc. | Ultrasound scanning system for skeletal imaging |
| US4458689A (en) * | 1982-09-03 | 1984-07-10 | Medtronic, Inc. | Ultrasound scanner with mapped data storage |
| US4457311A (en) * | 1982-09-03 | 1984-07-03 | Medtronic, Inc. | Ultrasound imaging system for scanning the human back |
| US4489729A (en) * | 1982-09-03 | 1984-12-25 | Medtronic, Inc. | Ultrasound imaging system |
| US4637256A (en) * | 1983-06-23 | 1987-01-20 | Matsushita Electric Industrial Co., Ltd. | Ultrasonic probe having dual-motion transducer |
| US4747411A (en) * | 1984-03-28 | 1988-05-31 | National Biochemical Research Foundation | Three-dimensional imaging system |
| US4798210A (en) * | 1984-03-28 | 1989-01-17 | National Biomedical Research Foundation | Three-dimensional imaging system |
| DE3585218D1 (en) * | 1984-11-09 | 1992-02-27 | Matsushita Electric Ind Co Ltd | ULTRASONIC IMAGING SYSTEM FOR THE SIMULTANEOUS DISPLAY OF SECTOR SCANNED MULTIPLE IMAGES. |
| JPS62170563U (en) * | 1986-04-18 | 1987-10-29 | ||
| DE3783281T2 (en) * | 1986-07-07 | 1993-07-22 | Matsushita Electric Ind Co Ltd | ULTRASONIC PROBE. |
| US4757722A (en) * | 1986-10-27 | 1988-07-19 | Glover Marvin J | Motion conversion apparatus |
| US4757823A (en) * | 1987-01-27 | 1988-07-19 | Hofmeister John F | Method and apparatus for measuring uterine blood flow |
| DE8717504U1 (en) * | 1987-10-19 | 1989-01-05 | Siemens Ag, 1000 Berlin Und 8000 Muenchen, De | |
| US4932414A (en) * | 1987-11-02 | 1990-06-12 | Cornell Research Foundation, Inc. | System of therapeutic ultrasound and real-time ultrasonic scanning |
| GB2212267B (en) * | 1987-11-11 | 1992-07-29 | Circulation Res Ltd | Methods and apparatus for the examination and treatment of internal organs |
| ATE128841T1 (en) * | 1987-11-13 | 1995-10-15 | Advanced Diagnostic Med Syst | ULTRASONIC PROBE. |
| US4841979A (en) * | 1988-01-25 | 1989-06-27 | Capistrano Labs, Inc. | Ultrasonic prostate probe assembly |
| US4896672A (en) * | 1988-03-28 | 1990-01-30 | Hewlett-Packard Company | Hardware corection scheme for inter-frame image jitter in a scanning probe ultrasound imaging system |
| US5107844A (en) * | 1989-04-06 | 1992-04-28 | Olympus Optical Co., Ltd. | Ultrasonic observing apparatus |
| FR2651990A1 (en) * | 1989-09-15 | 1991-03-22 | Philips Electronique Lab | Probe for echography in three dimensions |
| US5552592A (en) * | 1989-10-30 | 1996-09-03 | Symbol Technologies, Inc. | Slim scan module with dual detectors |
| DE69027284T2 (en) * | 1989-12-14 | 1996-12-05 | Aloka Co Ltd | Three-dimensional ultrasound scanner |
| JPH0773576B2 (en) * | 1992-05-27 | 1995-08-09 | アロカ株式会社 | Ultrasonic probe for 3D data acquisition |
| US5329194A (en) * | 1992-11-23 | 1994-07-12 | Capistrano Labs, Inc. | Ultrasonic peripheral vascular probe assembly |
| US5402789A (en) * | 1992-11-23 | 1995-04-04 | Capistrano Labs, Inc. | Ultrasonic peripheral vascular probe assembly |
| US5351692A (en) * | 1993-06-09 | 1994-10-04 | Capistrano Labs Inc. | Laparoscopic ultrasonic probe |
| US5445154A (en) * | 1993-08-26 | 1995-08-29 | Interspec, Inc. | Ultrasonic probe assembly with linear actuator |
| US5396890A (en) * | 1993-09-30 | 1995-03-14 | Siemens Medical Systems, Inc. | Three-dimensional scan converter for ultrasound imaging |
| US5842473A (en) * | 1993-11-29 | 1998-12-01 | Life Imaging Systems | Three-dimensional imaging system |
| US5531119A (en) * | 1994-04-19 | 1996-07-02 | Capistrano Labs, Inc. | Ultrasound probe with bubble trap |
| EP0754957B1 (en) * | 1995-07-17 | 2001-03-21 | Aloka Co. Ltd. | Ultrasound image processing apparatus and method for producing an ultrasound image |
| US6099474A (en) * | 1998-05-27 | 2000-08-08 | Solek; Roman | Ultrasound system for displaying real time simultaneous multiplane image |
| EP1034742A1 (en) * | 1999-03-09 | 2000-09-13 | Kreztechnik Aktiengesellschaft | Method for investigating objects with ultrasound |
| US6537219B2 (en) * | 2001-04-04 | 2003-03-25 | Koninklijke Philips Electronics N.V. | Static focus ultrasound apparatus and method |
| US6780153B2 (en) * | 2001-06-25 | 2004-08-24 | Angelsen Bjoern A. J. | Mechanism and system for 3-dimensional scanning of an ultrasound beam |
| AU2002335589A1 (en) * | 2002-07-15 | 2004-02-02 | Eagle Ultrasound As | A mechanism and system for 3-dimentional scanning of an ultrasound beam |
| US7396574B2 (en) | 2003-05-28 | 2008-07-08 | Robert C. Bogert | Self-inflating cushion and footwear including same |
| US7299806B2 (en) * | 2003-11-25 | 2007-11-27 | General Electric Company | Compliant probe interface assembly |
| US7905835B2 (en) * | 2008-01-15 | 2011-03-15 | General Electric Company | Method for assessing mechanical properties of an elastic material |
| US8820164B2 (en) * | 2012-01-31 | 2014-09-02 | Sikorsky Aircraft Corporation | Retroreflector for ultrasonic inspection |
| USD728849S1 (en) | 2012-05-03 | 2015-05-05 | Lumenpulse Lighting Inc. | LED projection fixture |
| USD741539S1 (en) * | 2014-02-28 | 2015-10-20 | Leeo, Inc. | Nightlight and air sensor |
| USD742059S1 (en) * | 2014-02-28 | 2015-10-27 | Leeo, Inc. | Nightlight and air sensor |
| USD741728S1 (en) * | 2014-02-28 | 2015-10-27 | Leeo, Inc. | Nightlight and air sensor |
| US10805775B2 (en) | 2015-11-06 | 2020-10-13 | Jon Castor | Electronic-device detection and activity association |
| US10945706B2 (en) | 2017-05-05 | 2021-03-16 | Biim Ultrasound As | Hand held ultrasound probe |
| CN111885960B (en) | 2018-03-13 | 2023-10-13 | 韦拉索恩股份有限公司 | Universal interlacing of ultrasound probes |
| GB2597995A (en) * | 2020-08-14 | 2022-02-16 | Dolphitech As | Ultrasound scanning system with adaptive gating |
Family Cites Families (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3334622A (en) * | 1964-12-15 | 1967-08-08 | Branson Instr | Method and apparatus for electroacoustic exploration |
| FR1497496A (en) * | 1966-05-06 | 1967-10-13 | Massiot Philips Sa | Ultrasonic analysis method and apparatus |
| US3454923A (en) * | 1968-02-01 | 1969-07-08 | Honeywell Inc | Transducer control apparatus |
| NO120353B (en) * | 1968-05-02 | 1970-10-05 | Simonsen & Mustad As | |
| US3832887A (en) * | 1969-06-25 | 1974-09-03 | Automation Ind Inc | Ultrasonic inspection apparatus |
| DE2060269C3 (en) * | 1970-12-08 | 1979-05-03 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Ultrasound device for medical diagnostics that works according to the pulse-echo method |
| US3792423A (en) * | 1972-05-24 | 1974-02-12 | Atomic Energy Commission | Isometric imaging system |
| US3751976A (en) * | 1972-07-24 | 1973-08-14 | Gen Electric | Ultrasonic inspection system with pseudo isometric display |
| US3802253A (en) * | 1972-08-18 | 1974-04-09 | Nasa | Ultrasonic biomedical measuring and recording apparatus |
| US3778757A (en) * | 1972-09-01 | 1973-12-11 | Gen Electric | Method and apparatus for visual imaging ultrasonic echo signals utilizing multiple transmitters for reduced specular reflection effects |
| US4031743A (en) * | 1973-05-03 | 1977-06-28 | The Commonwealth Of Australia, C/O Dept. Of Health | Ultrasonic echogram display |
| US3881466A (en) * | 1973-08-20 | 1975-05-06 | Advanced Diagnostic Res | Ultrasonic cross-sectional imaging system |
| JPS50135885A (en) * | 1974-04-05 | 1975-10-28 | ||
| US3979711A (en) * | 1974-06-17 | 1976-09-07 | The Board Of Trustees Of Leland Stanford Junior University | Ultrasonic transducer array and imaging system |
| JPS5122292A (en) * | 1974-08-16 | 1976-02-21 | Tokyo Shibaura Electric Co | CHOONPASHINDANSOCHI |
| US3918297A (en) * | 1974-10-03 | 1975-11-11 | Gen Electric | Acoustic imaging apparatus with gray scale display |
| GB1539512A (en) * | 1975-01-17 | 1979-01-31 | Greater Glasgow Health Board | Ultrasonic scanning apparatus |
| GB1532218A (en) * | 1975-06-26 | 1978-11-15 | Nat Res Dev | Acoustic holography apparatus |
| US4021771A (en) * | 1975-07-07 | 1977-05-03 | Holosonics, Inc. | Scan acoustical holographic imaging apparatus |
| US4131022A (en) * | 1976-03-04 | 1978-12-26 | Rca Corporation | Pulse-echo ultrasonic-imaging display system |
| AT358155B (en) * | 1976-04-08 | 1980-08-25 | Kretztechnik Gmbh | METHOD FOR EXAMINING OBJECTS WITH ULTRASOUND AFTER THE IMPULSE ECHO METHOD |
| DE2743485C3 (en) * | 1977-09-28 | 1980-09-04 | Hoechst Ag, 6000 Frankfurt | Process for the production of biologically effective granulates |
-
1978
- 1978-05-03 US US05/902,740 patent/US4271706A/en not_active Expired - Lifetime
-
1979
- 1979-03-27 DE DE2911957A patent/DE2911957B2/en not_active Withdrawn
- 1979-04-30 LU LU81205A patent/LU81205A1/en unknown
- 1979-04-30 ES ES480125A patent/ES480125A0/en active Granted
- 1979-05-01 GB GB7915168A patent/GB2020428B/en not_active Expired
- 1979-05-01 JP JP5398379A patent/JPS54144786A/en active Granted
- 1979-05-01 CA CA326,733A patent/CA1123504A/en not_active Expired
- 1979-05-02 IT IT22313/79A patent/IT1113927B/en active
- 1979-05-02 NL NLAANVRAGE7903435,A patent/NL187035C/en not_active IP Right Cessation
- 1979-05-02 MX MX177501A patent/MX146784A/en unknown
- 1979-05-02 DK DK180779AA patent/DK152154B/en not_active Application Discontinuation
- 1979-05-02 BE BE0/194941A patent/BE875980A/en not_active IP Right Cessation
- 1979-05-02 FR FR7911006A patent/FR2425081A1/en active Granted
- 1979-08-08 IE IE879/79A patent/IE48106B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ES8200555A1 (en) | 1981-11-16 |
| US4271706A (en) | 1981-06-09 |
| DK180779A (en) | 1979-11-04 |
| IE48106B1 (en) | 1984-10-03 |
| NL7903435A (en) | 1979-11-06 |
| JPS54144786A (en) | 1979-11-12 |
| GB2020428B (en) | 1982-12-22 |
| DE2911957B2 (en) | 1981-07-16 |
| NL187035C (en) | 1991-05-01 |
| DK152154B (en) | 1988-02-01 |
| MX146784A (en) | 1982-08-12 |
| GB2020428A (en) | 1979-11-14 |
| NL187035B (en) | 1990-12-03 |
| FR2425081B1 (en) | 1985-03-22 |
| FR2425081A1 (en) | 1979-11-30 |
| IE790879L (en) | 1979-11-03 |
| ES480125A0 (en) | 1981-11-16 |
| DE2911957A1 (en) | 1979-11-08 |
| BE875980A (en) | 1979-11-05 |
| JPS6221536B2 (en) | 1987-05-13 |
| IT7922313A0 (en) | 1979-05-02 |
| LU81205A1 (en) | 1979-11-07 |
| IT1113927B (en) | 1986-01-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1123504A (en) | Ultrasonic scanner | |
| CA1275322C (en) | Three-dimensional imaging system | |
| US4667199A (en) | Simulator | |
| US7456779B2 (en) | System and method for 3D radar image rendering | |
| Dutt et al. | Ultrasound echo envelope analysis using a homodyned K distribution signal model | |
| US6315724B1 (en) | 3-dimensional ultrasonic imaging | |
| Mitchell et al. | Quantitative backscatter measurements with a long-range side-scan sonar | |
| US4530077A (en) | Efficient low cost transducer system | |
| GB2048476A (en) | Method and apparatus for ultrasonic imaging using a line source and a linear receiver array | |
| US4688430A (en) | Device for imaging three dimensions with a single pulse transmission | |
| US3618007A (en) | Vertical obstacle profiling sonar | |
| Wong et al. | Characterization and decomposition of waveforms for LARSEN 500 airborne system | |
| US4145680A (en) | Acoustic imaging system | |
| US4472972A (en) | Ultrasound imaging system employing operator controlled filter for reflected signal attenuation compensation | |
| US4281661A (en) | Medical echo sounding apparatus with a wide sector scanning angle | |
| CA1162285A (en) | Ultrasonic apparatus for sector scanning | |
| US4361043A (en) | Reference voltage generation means for controlling a display | |
| Schock et al. | Buried object scanning sonar for AUVs | |
| From | Sporadic E movement followed with a pencil beam high frequency radar | |
| US4512196A (en) | Ultrasound imaging with FM detection | |
| Sutton et al. | Description of a Navy Holographic Underwater Acoustic Imaging System (AIS) | |
| Axelsson et al. | Programmable scanner for laser bathymetry | |
| Guenther et al. | Laser Bathymetry for Near Shore Charting Application (Preliminary Field Text Results) | |
| Lhermitte et al. | Multi‐beam Doppler sonar observation of tidal flow turbulence | |
| Dixon | Wideband imaging of distributed objects using wavelet transforms and generalized inverse theory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |