CA1168346A - Apparatus for ultrasonic scanning - Google Patents
Apparatus for ultrasonic scanningInfo
- Publication number
- CA1168346A CA1168346A CA000362599A CA362599A CA1168346A CA 1168346 A CA1168346 A CA 1168346A CA 000362599 A CA000362599 A CA 000362599A CA 362599 A CA362599 A CA 362599A CA 1168346 A CA1168346 A CA 1168346A
- Authority
- CA
- Canada
- Prior art keywords
- partial
- line
- ultrasonic scanning
- scanning apparatus
- stores
- 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
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
- G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
- G01S7/52023—Details of receivers
- G01S7/52025—Details of receivers for pulse systems
- G01S7/52026—Extracting wanted echo signals
- G01S7/52028—Extracting wanted echo signals using digital techniques
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Acoustics & Sound (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Ultra Sonic Daignosis Equipment (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
ABSTRACT
Ultrasonic scanning apparatus is disclosed. The apparatus includes electronic delay circuitry for delaying echo signals produced in use by a multi-plicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained. The circuitry comprises a multiplicity of partial-line stores; each partial-line store being adapted for storing data corresponding to a part of an ultrasonic scanning line, asso-ciated in groups of at least three with respective ones of the transducers and control means arranged such that, in use, data corresponding to echo signals is sequentially written in to the partial-line stores of the group for each of the transducers, beginning with the first such transducer to receive an echo signal, until at least the first partial-line store of the group for the last such transducer to receive an echo signal has been supplied with data, after which, data can be simultaneously read out from all of the partial-line stores.
Ultrasonic scanning apparatus is disclosed. The apparatus includes electronic delay circuitry for delaying echo signals produced in use by a multi-plicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained. The circuitry comprises a multiplicity of partial-line stores; each partial-line store being adapted for storing data corresponding to a part of an ultrasonic scanning line, asso-ciated in groups of at least three with respective ones of the transducers and control means arranged such that, in use, data corresponding to echo signals is sequentially written in to the partial-line stores of the group for each of the transducers, beginning with the first such transducer to receive an echo signal, until at least the first partial-line store of the group for the last such transducer to receive an echo signal has been supplied with data, after which, data can be simultaneously read out from all of the partial-line stores.
Description
Thls invention relates to ultrasonic scanning apparatus.
Ultrasonic apparatus is disclosed in Ultrasonics Symposium Proceedings, IEEE Cat. 1977, pages 250 to 25~, which apparatus is provided with storage members as part of a delay device, the individual stores being whole-line stores, that is to say, they store an entire ultra-sound line. The write-in and read-out of a line takes place according to the so-called alternating buffer store principle, that is to say, data ls read into one of two line stores just as data is being read out of the associated second store. The principle of such an alternating buffer store is a:Lso described inter alia in German Patent Specification No. 26 29 895. The use of whole-line stores, however, has the disadvantage that, where a relatively large number of transducer ele-ments is present, an unnecessarily large amount of storage capacity is required.
According to the present invention there is provided ultrasonic scanning apparatus including electronic delay circuitry for delaying echo sig-nals produced in use by a multiplicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained for each of a succession of ultrasonic scanning lines, the circuitry comprising a multiplicity of partial-line digital stores, each partial-line digital store being adapted for storing data in digital form corresponding to a part of an ultrasonic scanning line, a group of partial-line digital stores being associated with each of the transducers such that the total number of partial-line digital stores available for association with each transducer has a total storage capacity substantially less than that required for storing the data from the transducer which is to be stored during the generation of an ultrasonic scanning line, each group comprising at least three partial-line digital stores and being operated such that readout of part of the data of one ultrasonic scanning line makes room for the storage of a further part of the data of the same ultrasonic scanning line, and control means arranged such 3~j that, in use~ data corresponding to echo s:Lgnals :i9 sequentiall-y wrltten in to the partial-line digital stores oE the group for each of the transducers, be-ginning with the Eirst such transducer to receive an echo signal, until at least the Eirst partial-line digital store of the group for the last such trans-ducer to receive an echo signal has been supplied with data, said control means being operative for simultaneously reading out stored data from all of the groups of partial-line digital stores after the time when the group of partial-line digital stores for the last such transducer to receive an echo signal has been supplied w:Lth data and before the group of part:Lal-line digital stores associated with the first such transducer to receive an echo signal has exceed-ed its storage capacity.
The control means is preferably arranged to produce a signal to ~la-~6~
enable the said simultaneous reading~out of data from all the partial-line stores. This signal could be in the form of a pulse.
The storage capacity of each partial-line store could correspond at least to a maximum delay time before the said last such transducer receives an echo signal in use. In this caseJ the storage capacity oE each partial-line store is preEerably matched to the said maximum delay time, for scanning by pivoting of a beam produced by the ultrasonic scanning apparatus.
Alternatively, the minimum storage capacity of each partial-line store could be determined by a focus setting time of the ultrasonic scanning appara-tus, for dynamic focusing of the apparatus. In this case, the storage capacityof each partial~line store, with a delay time of substantially zero before the said last such transducer receives an echo signal in use, could be adapted to set the value of the said :Eocus setting time, :Eor purely dynamic Eocusing oE
the apparatus. Alternatively, the minimum storage capacity o:E each partial-line store could also be determined by a maximum delay time before the said last transducer receives an echo signal in use.
The ultrasonic scanning apparatus could Eurther comprise means for processing digital signals. In this case, the partial-line stores could com-prise random access memories. Also, the control means could then comprise a programmed device. In this case, the scanning apparatus could further comprise an address co~mter associated with the programmed device. A control pulse gen-erator could be associated with the progranmled device also. The control means could also comprise a further programmed device and a further address counter associated with such a further programmed device. The apparatus could also comprise an address adder associated with the further programmed device. This address adder could be arranged to control the partial-line stores via an ad-dress multiplexer.
The invention will now be described, by way of example, with refer-ence to the accompanyIng drawings, in which~
Figure 1 is a diagrammatic illustration of the manner of operation o'c ultrasonic apparatus using pure beam pivoting with or without dynamic focusing;
Figure 2 is a diagram corresponding to the diagram of Figure 1 for apparatus using only dynamic focusing;
Figure 3 shows a block circui-t diagram of part of ultrasonic scan-ning apparatus associated with an inclividual transducer element; and Figure ~ shows a block circuit diagram of the same ultrasonic scan-ning apparatus :Eor a whole array of transducer elements.
Referring to Figure 1, on the leEt-hand side of the diagram a trans-ducer element array Wl to Wn is schematically indicated. Beam pivoting move-ment of the ultrasonic scanning apparatus in question is so chosen (as indi-cated by the chain delay line 1~ that echo signals, received back after emis-sion of transmitted signals, first arrive as data at the transducer element Wl, whereas succeeding transducer elements W2, W3, etc. receive echo data only with increasing delay times. The last element Wn o:E the array of transducer elements receives, last of all the elements, echo data with a maximum time delay ~ max The scanning direction of the ultrasonic beam can be varied as desired (for example by programming). By appropriate pre-selection of dif-ferent delay times, the angle of the chain delay line 1 is also varied, the main direction of radiation of the ultrasonic scanning rays being, of course, substantially perpendicular to this delay line 1. However, the whole arrange-ment is always such that the maximum delay time of that transducer element which is always the last *o be reached in each instance ~in the present case Wn, or Wl in the case of reflection of the direction of radiation at the axis of symmetry of the transducer element array Wl to Wn) does not exceed the pre-selected value ~ x 3 ..~ 3~
There is associated with each -transducer element Wl to Wn of the transducer element array Wl to Wn a set of three partial-line stores of which each store only ever dynamically stores a prede-termined fraction oE a whole line ~for example, one-sixteenth of a whole line). In Figure 1, the partial-line stores of a set of three are respectively denoted by I, II and [II. All of the partial-line stores of a set of three can be continuously and success-ively filled with data. The entry of data into the set of three is thus such that, commencing with the transducer element which is always the first to be reached by data in each instance (in the present case Wl), the data of this element is sequentially read into the individual partial-line stores I, II and III until at least the first partial-line store I of the transducer element which is always the last to be reached by data (in the present case Wn) is filled with this data. In this case, a read-start pulse is produced as a re-sult of which the data which has entered all of the partial-line stores is simultaneously read out.
In the diagram of Figure 1) a start instant STE for writing-in S of data is indicated by the arrival of the first data at the first transducer element Wl of the transducer element array Wl to Wn. For each successive trans-ducer element Wi, the writing-in S takes place with a delay in relation to the start instant STE corresponding to the delay time with which further data ar-rives. Finally, with regard to the last transducer element lYn, data is writ-ten into its first partial-line store I with a delay equal to the time ~ max However~ when this first partial-line-store I of the transducer element Wn has been filled, a read-start pulse for the simultaneous read-out L of data in al]
of the partial-line stores of all of the transducer elements Wl to Wn can be emitted. In Figure 1, the start instant STL for the read-start pulse is some-what delayedJ because a setting time L~F for the ultrasonic beam focus is included i.n the storage -time. This additional time interval is always taken into consideration when dynamic focusing is performed simultaneously with piv-oting movement of the ultrasonic beam.
Referring to Figure 2, which relates to ultrasonic apparatus which uses merely dynamic focusing without pivoting movement of the ultrasonic beam~
in this case the delay time ~ is O and only the aforesai.d focus setting time ~ FmaX becomes operative. This focus setting time ~ FmaX varies in depen-dence upon the depth ~ of the object being examined from which echo signals are to be sharply received (in focused form). The variation diagram for the focus setting time ~ F x is diagrammatically shown as ~ F (~) in Figure 2.
On the basis of purely dynamic. focusing, there is obtained for each difference in focus a di.fferent delay variation, for example in accordance with the curvedchain line 2.
In Figure 3, a transmission pulse generator for generating ultrasonic transmission pulses A is denoted by the reference numeral 3. This transmission pulse generator 3 generates pulses A in step with trigger pulses produced by a master generator 4 which, in turn, is controlled by a programming unit 5 in which a transmission program is stored on demand in accordance with the relation~
ship ATQ ~ ~ J P), where: A denotes the case of transmission; T denotes the respective transmission delay time; Q indicates that quantised values are pre-sent; ~ is the pivoting angle of the ultrasonic radiation; and ~ is the loca~
tion of an activated transducer element in the transducer element array Wl to Wn. Ultrasonic echo signals in an object under examination produced as a re-sult of the emission of a transmission pulse A from a transducer element or a group of transducer elements, and received back, are directed by a respective transducer element to a high-frequency amplifier 6 (80 dB ampli~ier) after hav-ing been reconverted into corresponding electrical signals E ~t). The result-~ f~3 ing amplified echo signals are then rectified by a full-wave rectifier 7 and the rectified signal is thereafter supplied, via an anolog-to-digital converter 8, to a unit consisting of a combination ot a data multiplexer 9 and a two's complement forming device lO. At the output of the combined unit 9 and 10 there is finally connected a set 11 of three partial-line stores I, II, III coJn-prising three RAM stores which have a capac.ity of, for example, 256 x ~ bits.
The use of the combined unit comprising the data multiplexer 9 and the two's complement forming device 10 has the purpose that, in the visual-isation of echo signals, there exists on the one hand a need for high image resolution. Ilowever, on the other hand, there are generally required for this purpose analog-to-digital converters having a high bit number, which are expen-sive. Optimum phase co-ordination of received echo signals after the delay has occurred is also required. A summing arrangement required for this purpose should be of simplest possible construction. These problems are solved in a surprisingly simple manner by the circuit arrangemeDt 6 to 10. The solution proceeds from the fact that the echo signals produced contain both positive and negative components related to zero line potential. ~ccordingly, an analog-to-digital converter would have to convert the whole dynamic range from maximum negative amplitude to maximum positive amplitude, but for this purpose analog-to-digital converters having a relatively high bit number would be required to make it possible to achieve an acceptable image resolution value. However, very much more favourable conditions arise if an echo signcal produced is rec-tified before conversion to digital form. After rectifica~ion, the resolution is concentrated only on signal components of a single polarity. With an equal-ly good degree of image resolution, one less bit is thereby required. In this way, the bit number which the analog-to-digital converter requires for the same image resolution is also reduced by one bit and the converter thus becomes cheaper. Since recti.fication at the same time also involves loss of sign, how-ever, it must be ensured that a sign signal is formed, which sign signal must appear throughout further signal processing as :Ear as a swmning device as an accompaniment to the signal components to be processed and which finally re-unites the components with the correct sign before image display. There can be utilised as the carrier of the sign information in a simple, optimum and sur-prising manner, the one bit which now need not be generated by the analog-to-digital converter, but instead is directly formed by a sign detector and can be utilised to carry the sign information. In the circuit diagram of Figure 3, the amplifier 6 is accordingly simultaneously constructed as a sign detector for positive and negative components of the echo signals E(t) produced. Depend-ing upon the sign detected, there is generated a signal which controls, via a sign signal line, the combination of the multiplexer 9 and the two's complement forming device 10 in the sense of a routing device for the signal produced by the analog-to-digital converter 8. The amplifier 6 operates to generate a sign signal in the form of a sign bit only in the presence of negati~e components of the echo signals E ~t) and then supplies the s7gn bit via the sign signal line to the multiplexer 9 and the two's complement forming device 10. The two devices 9 and 10 are then operated in dependence upon the sign signal in such manner that, when there is no signal in the sign signal line, i.e. in th:e pres~
ence of positive signal components, the output information of the analog-to-digital converter 8 is directly passed on, with the sign bit, to the set of three partial-line stores 11 via the data multiplexer 9. On the other hand, when negative components are detected, the output information of the analog-to-digital converter 8 is switched-over to the input of the two's complement forming device 10 by means of the signal which is then present on the sign sig-nal Iine in each instance. The two's complement forming devi~e 10 then forms two's coMplement in formation 2~K to the output information of the analog-to-digital converter 8 and passes on the two's complement information 2-K together with the sign bit to the set of three partial-line stores 11. The delay here takes place in the modes of operation already described in the foregoing with reference to Figures 1 and 2. The respective function is again controlled by program stores 12 and/or 13 which separately control each set of three partial-line stores 11 in combination with address counters and release (enabling) de-vices. In the circ~lit diagram of Figure 3, the block 1~ represents a linear address counter for writing-in S and the block 15 represents a generator for producing writing enable pulses. Correspondingly, the block 16 represents an address counter for reading-out, the block 17 represents an address adder, and the block 18 represen~s an address multiplexer for seeking the addresses for writing-in S and reading-out L. The program store 12 specifically supplies data for the setting of delay times in accordance with the relationship: TRQ
~ = m); where: T is again the delay time; R represents the case of reception; Q again means that quantised values are present; ~ is again the pivoting angle; and ~ is the location of the activated transducer element on the row of transducer elements Wl to Wn. The parameter ~ defines the depth of penetration and m, the last of a given number 0 to m of focusing ranges which can be set stepwise throughout the range of examination depths. The program store 13, on the other hand, makes available control programs for dynamic focus-ing when these are required. The program for dynamic focusing is built-up in accordance with the relationship: ~m { TRQ (~ S ,) - TRQ ~ = m)}.
It is possible to either use both programming stores 12 and 13 in combination, or to use only one of them without activation of the other.
The basic circuit for the further processing of signals emanating from each individual transducer element Wl to Wn, in such a manner that they are united in correct phase, is illustrated in l;igure ~. In this figure, the whole row of all the tTansducer elements is again indicated by Wl to Wn. Each transducer element is succeeded by a block Bl to Bn, each of which is built-up in accordance with the circuitry shown in the circuit diagram of ~igure 3. Thc outputs of all of the blocks Bl to Bn are connected with a digital adder 19 for adding their output signals. On the basis of the previously explained selection of the combination of the multiplexer 9 with the two's complement :Eorming dev;ce lO, the digital adder 19 can be designed in a particularly simple manner as a simple sumlming circuit. Without the use of the two's complement forming device 10, on the other hand, it would be necessary to form both sums aJId differences, whereby ~he cost of the adder 19 would be considerably increased. A pure summa-tion is possible because~ as already explained, each negative component of the echo signals E(t) carries with it the information of the minus sign as a result of the two's complement formation. After a simple addition has been performed, the resulting signal is supplied to a succeeding network comprising a digital equalisation amplifier 20 and a digital demodulator 21. The resulting demod~
ulated digital signals are then finally directed via a digital filter 22 to a rounding device 23 for bit number reduction. The data-reduced signal obtained at the output of the rounding device 23, which converts ll~bit data into 8-bit data, is then passed in the direction of the arrow 24, for example via image stores (not shown) or the like, to an image display tube (not shown) for dis~
play. The control of the blocks Bl to Bn and 19 to 23 in Figure 4 takes place by means of a microprogram control unit 25, which also permits variations of the program for the operation of the blocks Bl to Bn. The central clock is an oscillator 26.
The storage capacity of a partial~line store depends substantially only upon the maximum delay time ~ max of the transducer element array Wl to Wn.
t,~P~
Since the delay time'l~n!ax is generally yery small e-ven with large pivoting angles - it amounts to a fraction, :For example 1/16 or even lessl of the total storage time of a whole-line store; the storage time required is always rela-tively small and hence the storage capacity of the partial-line store involved is always optimally low. Consequently, with a large number of transducer ele-ments in the transducer element array Wl to Wn, ~he total requirement o:f stor-age capacity is optimally low.
The arrangement described may be applied to so-called phased arrays, for example for carryi.ng out sector scanning by beam pivoting on the basis of difEering signal delay. Application in combination with dynamic focusing or to linear arrays witllout beam pivoting, but with clynamic focusing, is equally possible as described. - ~
Using digital techniques has the advantage that the whole arrangement can be controlled on a software basis. This not only renders possible trouble-free and rapidly variable control, but since no analog ultrasonic signals have to be dealt with anywhere in the control circuitry (as, for example, in the LC
technique), no small switching clicks occur which act as disturbing echoes in the image. Also, stability is further enhanced in comparison with CCD stores ~charge coupled devices) or BBD stores (bucket brigade devices or bucket chain stores).
- 10 ~
;
Ultrasonic apparatus is disclosed in Ultrasonics Symposium Proceedings, IEEE Cat. 1977, pages 250 to 25~, which apparatus is provided with storage members as part of a delay device, the individual stores being whole-line stores, that is to say, they store an entire ultra-sound line. The write-in and read-out of a line takes place according to the so-called alternating buffer store principle, that is to say, data ls read into one of two line stores just as data is being read out of the associated second store. The principle of such an alternating buffer store is a:Lso described inter alia in German Patent Specification No. 26 29 895. The use of whole-line stores, however, has the disadvantage that, where a relatively large number of transducer ele-ments is present, an unnecessarily large amount of storage capacity is required.
According to the present invention there is provided ultrasonic scanning apparatus including electronic delay circuitry for delaying echo sig-nals produced in use by a multiplicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained for each of a succession of ultrasonic scanning lines, the circuitry comprising a multiplicity of partial-line digital stores, each partial-line digital store being adapted for storing data in digital form corresponding to a part of an ultrasonic scanning line, a group of partial-line digital stores being associated with each of the transducers such that the total number of partial-line digital stores available for association with each transducer has a total storage capacity substantially less than that required for storing the data from the transducer which is to be stored during the generation of an ultrasonic scanning line, each group comprising at least three partial-line digital stores and being operated such that readout of part of the data of one ultrasonic scanning line makes room for the storage of a further part of the data of the same ultrasonic scanning line, and control means arranged such 3~j that, in use~ data corresponding to echo s:Lgnals :i9 sequentiall-y wrltten in to the partial-line digital stores oE the group for each of the transducers, be-ginning with the Eirst such transducer to receive an echo signal, until at least the Eirst partial-line digital store of the group for the last such trans-ducer to receive an echo signal has been supplied with data, said control means being operative for simultaneously reading out stored data from all of the groups of partial-line digital stores after the time when the group of partial-line digital stores for the last such transducer to receive an echo signal has been supplied w:Lth data and before the group of part:Lal-line digital stores associated with the first such transducer to receive an echo signal has exceed-ed its storage capacity.
The control means is preferably arranged to produce a signal to ~la-~6~
enable the said simultaneous reading~out of data from all the partial-line stores. This signal could be in the form of a pulse.
The storage capacity of each partial-line store could correspond at least to a maximum delay time before the said last such transducer receives an echo signal in use. In this caseJ the storage capacity oE each partial-line store is preEerably matched to the said maximum delay time, for scanning by pivoting of a beam produced by the ultrasonic scanning apparatus.
Alternatively, the minimum storage capacity of each partial-line store could be determined by a focus setting time of the ultrasonic scanning appara-tus, for dynamic focusing of the apparatus. In this case, the storage capacityof each partial~line store, with a delay time of substantially zero before the said last such transducer receives an echo signal in use, could be adapted to set the value of the said :Eocus setting time, :Eor purely dynamic Eocusing oE
the apparatus. Alternatively, the minimum storage capacity o:E each partial-line store could also be determined by a maximum delay time before the said last transducer receives an echo signal in use.
The ultrasonic scanning apparatus could Eurther comprise means for processing digital signals. In this case, the partial-line stores could com-prise random access memories. Also, the control means could then comprise a programmed device. In this case, the scanning apparatus could further comprise an address co~mter associated with the programmed device. A control pulse gen-erator could be associated with the progranmled device also. The control means could also comprise a further programmed device and a further address counter associated with such a further programmed device. The apparatus could also comprise an address adder associated with the further programmed device. This address adder could be arranged to control the partial-line stores via an ad-dress multiplexer.
The invention will now be described, by way of example, with refer-ence to the accompanyIng drawings, in which~
Figure 1 is a diagrammatic illustration of the manner of operation o'c ultrasonic apparatus using pure beam pivoting with or without dynamic focusing;
Figure 2 is a diagram corresponding to the diagram of Figure 1 for apparatus using only dynamic focusing;
Figure 3 shows a block circui-t diagram of part of ultrasonic scan-ning apparatus associated with an inclividual transducer element; and Figure ~ shows a block circuit diagram of the same ultrasonic scan-ning apparatus :Eor a whole array of transducer elements.
Referring to Figure 1, on the leEt-hand side of the diagram a trans-ducer element array Wl to Wn is schematically indicated. Beam pivoting move-ment of the ultrasonic scanning apparatus in question is so chosen (as indi-cated by the chain delay line 1~ that echo signals, received back after emis-sion of transmitted signals, first arrive as data at the transducer element Wl, whereas succeeding transducer elements W2, W3, etc. receive echo data only with increasing delay times. The last element Wn o:E the array of transducer elements receives, last of all the elements, echo data with a maximum time delay ~ max The scanning direction of the ultrasonic beam can be varied as desired (for example by programming). By appropriate pre-selection of dif-ferent delay times, the angle of the chain delay line 1 is also varied, the main direction of radiation of the ultrasonic scanning rays being, of course, substantially perpendicular to this delay line 1. However, the whole arrange-ment is always such that the maximum delay time of that transducer element which is always the last *o be reached in each instance ~in the present case Wn, or Wl in the case of reflection of the direction of radiation at the axis of symmetry of the transducer element array Wl to Wn) does not exceed the pre-selected value ~ x 3 ..~ 3~
There is associated with each -transducer element Wl to Wn of the transducer element array Wl to Wn a set of three partial-line stores of which each store only ever dynamically stores a prede-termined fraction oE a whole line ~for example, one-sixteenth of a whole line). In Figure 1, the partial-line stores of a set of three are respectively denoted by I, II and [II. All of the partial-line stores of a set of three can be continuously and success-ively filled with data. The entry of data into the set of three is thus such that, commencing with the transducer element which is always the first to be reached by data in each instance (in the present case Wl), the data of this element is sequentially read into the individual partial-line stores I, II and III until at least the first partial-line store I of the transducer element which is always the last to be reached by data (in the present case Wn) is filled with this data. In this case, a read-start pulse is produced as a re-sult of which the data which has entered all of the partial-line stores is simultaneously read out.
In the diagram of Figure 1) a start instant STE for writing-in S of data is indicated by the arrival of the first data at the first transducer element Wl of the transducer element array Wl to Wn. For each successive trans-ducer element Wi, the writing-in S takes place with a delay in relation to the start instant STE corresponding to the delay time with which further data ar-rives. Finally, with regard to the last transducer element lYn, data is writ-ten into its first partial-line store I with a delay equal to the time ~ max However~ when this first partial-line-store I of the transducer element Wn has been filled, a read-start pulse for the simultaneous read-out L of data in al]
of the partial-line stores of all of the transducer elements Wl to Wn can be emitted. In Figure 1, the start instant STL for the read-start pulse is some-what delayedJ because a setting time L~F for the ultrasonic beam focus is included i.n the storage -time. This additional time interval is always taken into consideration when dynamic focusing is performed simultaneously with piv-oting movement of the ultrasonic beam.
Referring to Figure 2, which relates to ultrasonic apparatus which uses merely dynamic focusing without pivoting movement of the ultrasonic beam~
in this case the delay time ~ is O and only the aforesai.d focus setting time ~ FmaX becomes operative. This focus setting time ~ FmaX varies in depen-dence upon the depth ~ of the object being examined from which echo signals are to be sharply received (in focused form). The variation diagram for the focus setting time ~ F x is diagrammatically shown as ~ F (~) in Figure 2.
On the basis of purely dynamic. focusing, there is obtained for each difference in focus a di.fferent delay variation, for example in accordance with the curvedchain line 2.
In Figure 3, a transmission pulse generator for generating ultrasonic transmission pulses A is denoted by the reference numeral 3. This transmission pulse generator 3 generates pulses A in step with trigger pulses produced by a master generator 4 which, in turn, is controlled by a programming unit 5 in which a transmission program is stored on demand in accordance with the relation~
ship ATQ ~ ~ J P), where: A denotes the case of transmission; T denotes the respective transmission delay time; Q indicates that quantised values are pre-sent; ~ is the pivoting angle of the ultrasonic radiation; and ~ is the loca~
tion of an activated transducer element in the transducer element array Wl to Wn. Ultrasonic echo signals in an object under examination produced as a re-sult of the emission of a transmission pulse A from a transducer element or a group of transducer elements, and received back, are directed by a respective transducer element to a high-frequency amplifier 6 (80 dB ampli~ier) after hav-ing been reconverted into corresponding electrical signals E ~t). The result-~ f~3 ing amplified echo signals are then rectified by a full-wave rectifier 7 and the rectified signal is thereafter supplied, via an anolog-to-digital converter 8, to a unit consisting of a combination ot a data multiplexer 9 and a two's complement forming device lO. At the output of the combined unit 9 and 10 there is finally connected a set 11 of three partial-line stores I, II, III coJn-prising three RAM stores which have a capac.ity of, for example, 256 x ~ bits.
The use of the combined unit comprising the data multiplexer 9 and the two's complement forming device 10 has the purpose that, in the visual-isation of echo signals, there exists on the one hand a need for high image resolution. Ilowever, on the other hand, there are generally required for this purpose analog-to-digital converters having a high bit number, which are expen-sive. Optimum phase co-ordination of received echo signals after the delay has occurred is also required. A summing arrangement required for this purpose should be of simplest possible construction. These problems are solved in a surprisingly simple manner by the circuit arrangemeDt 6 to 10. The solution proceeds from the fact that the echo signals produced contain both positive and negative components related to zero line potential. ~ccordingly, an analog-to-digital converter would have to convert the whole dynamic range from maximum negative amplitude to maximum positive amplitude, but for this purpose analog-to-digital converters having a relatively high bit number would be required to make it possible to achieve an acceptable image resolution value. However, very much more favourable conditions arise if an echo signcal produced is rec-tified before conversion to digital form. After rectifica~ion, the resolution is concentrated only on signal components of a single polarity. With an equal-ly good degree of image resolution, one less bit is thereby required. In this way, the bit number which the analog-to-digital converter requires for the same image resolution is also reduced by one bit and the converter thus becomes cheaper. Since recti.fication at the same time also involves loss of sign, how-ever, it must be ensured that a sign signal is formed, which sign signal must appear throughout further signal processing as :Ear as a swmning device as an accompaniment to the signal components to be processed and which finally re-unites the components with the correct sign before image display. There can be utilised as the carrier of the sign information in a simple, optimum and sur-prising manner, the one bit which now need not be generated by the analog-to-digital converter, but instead is directly formed by a sign detector and can be utilised to carry the sign information. In the circuit diagram of Figure 3, the amplifier 6 is accordingly simultaneously constructed as a sign detector for positive and negative components of the echo signals E(t) produced. Depend-ing upon the sign detected, there is generated a signal which controls, via a sign signal line, the combination of the multiplexer 9 and the two's complement forming device 10 in the sense of a routing device for the signal produced by the analog-to-digital converter 8. The amplifier 6 operates to generate a sign signal in the form of a sign bit only in the presence of negati~e components of the echo signals E ~t) and then supplies the s7gn bit via the sign signal line to the multiplexer 9 and the two's complement forming device 10. The two devices 9 and 10 are then operated in dependence upon the sign signal in such manner that, when there is no signal in the sign signal line, i.e. in th:e pres~
ence of positive signal components, the output information of the analog-to-digital converter 8 is directly passed on, with the sign bit, to the set of three partial-line stores 11 via the data multiplexer 9. On the other hand, when negative components are detected, the output information of the analog-to-digital converter 8 is switched-over to the input of the two's complement forming device 10 by means of the signal which is then present on the sign sig-nal Iine in each instance. The two's complement forming devi~e 10 then forms two's coMplement in formation 2~K to the output information of the analog-to-digital converter 8 and passes on the two's complement information 2-K together with the sign bit to the set of three partial-line stores 11. The delay here takes place in the modes of operation already described in the foregoing with reference to Figures 1 and 2. The respective function is again controlled by program stores 12 and/or 13 which separately control each set of three partial-line stores 11 in combination with address counters and release (enabling) de-vices. In the circ~lit diagram of Figure 3, the block 1~ represents a linear address counter for writing-in S and the block 15 represents a generator for producing writing enable pulses. Correspondingly, the block 16 represents an address counter for reading-out, the block 17 represents an address adder, and the block 18 represen~s an address multiplexer for seeking the addresses for writing-in S and reading-out L. The program store 12 specifically supplies data for the setting of delay times in accordance with the relationship: TRQ
~ = m); where: T is again the delay time; R represents the case of reception; Q again means that quantised values are present; ~ is again the pivoting angle; and ~ is the location of the activated transducer element on the row of transducer elements Wl to Wn. The parameter ~ defines the depth of penetration and m, the last of a given number 0 to m of focusing ranges which can be set stepwise throughout the range of examination depths. The program store 13, on the other hand, makes available control programs for dynamic focus-ing when these are required. The program for dynamic focusing is built-up in accordance with the relationship: ~m { TRQ (~ S ,) - TRQ ~ = m)}.
It is possible to either use both programming stores 12 and 13 in combination, or to use only one of them without activation of the other.
The basic circuit for the further processing of signals emanating from each individual transducer element Wl to Wn, in such a manner that they are united in correct phase, is illustrated in l;igure ~. In this figure, the whole row of all the tTansducer elements is again indicated by Wl to Wn. Each transducer element is succeeded by a block Bl to Bn, each of which is built-up in accordance with the circuitry shown in the circuit diagram of ~igure 3. Thc outputs of all of the blocks Bl to Bn are connected with a digital adder 19 for adding their output signals. On the basis of the previously explained selection of the combination of the multiplexer 9 with the two's complement :Eorming dev;ce lO, the digital adder 19 can be designed in a particularly simple manner as a simple sumlming circuit. Without the use of the two's complement forming device 10, on the other hand, it would be necessary to form both sums aJId differences, whereby ~he cost of the adder 19 would be considerably increased. A pure summa-tion is possible because~ as already explained, each negative component of the echo signals E(t) carries with it the information of the minus sign as a result of the two's complement formation. After a simple addition has been performed, the resulting signal is supplied to a succeeding network comprising a digital equalisation amplifier 20 and a digital demodulator 21. The resulting demod~
ulated digital signals are then finally directed via a digital filter 22 to a rounding device 23 for bit number reduction. The data-reduced signal obtained at the output of the rounding device 23, which converts ll~bit data into 8-bit data, is then passed in the direction of the arrow 24, for example via image stores (not shown) or the like, to an image display tube (not shown) for dis~
play. The control of the blocks Bl to Bn and 19 to 23 in Figure 4 takes place by means of a microprogram control unit 25, which also permits variations of the program for the operation of the blocks Bl to Bn. The central clock is an oscillator 26.
The storage capacity of a partial~line store depends substantially only upon the maximum delay time ~ max of the transducer element array Wl to Wn.
t,~P~
Since the delay time'l~n!ax is generally yery small e-ven with large pivoting angles - it amounts to a fraction, :For example 1/16 or even lessl of the total storage time of a whole-line store; the storage time required is always rela-tively small and hence the storage capacity of the partial-line store involved is always optimally low. Consequently, with a large number of transducer ele-ments in the transducer element array Wl to Wn, ~he total requirement o:f stor-age capacity is optimally low.
The arrangement described may be applied to so-called phased arrays, for example for carryi.ng out sector scanning by beam pivoting on the basis of difEering signal delay. Application in combination with dynamic focusing or to linear arrays witllout beam pivoting, but with clynamic focusing, is equally possible as described. - ~
Using digital techniques has the advantage that the whole arrangement can be controlled on a software basis. This not only renders possible trouble-free and rapidly variable control, but since no analog ultrasonic signals have to be dealt with anywhere in the control circuitry (as, for example, in the LC
technique), no small switching clicks occur which act as disturbing echoes in the image. Also, stability is further enhanced in comparison with CCD stores ~charge coupled devices) or BBD stores (bucket brigade devices or bucket chain stores).
- 10 ~
;
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED A E DEFINED AS FOLLOWS:
1. Ultrasonic scanning apparatus including electronic delay circuitry for delaying echo signals produced in use by a multiplicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained for each of a succession of ultrasonic scanning lines, the circuitry comprising a multiplicity of partial-line digital stores, each partial-line digital store being adapted for storing data in digital form corresponding to a part of an ultrasonic scanning line, a group of partial-line digital stores being associated with each of the transducers such that the total number of partial-line digital stores available for association with each transducer has a total storage capacity substantially less than that required for storing the data from the transducer which is to be stored during the generation of an ultrasonic scanning line, each group comprising at least three partial-line digital stores and being operated such that readout of part of the data of one ultrasonic scanning line makes room for the storage of a further part of the data of the same ultrasonic scanning line, and control means ar-ranged such that, in use, data corresponding to echo signals is sequentially written in to the partial-line digital stores of the group for each of the transducers, beginning with the first such transducer to receive an echo signal, until at least the first partial-line digital store of the group for the last such transducer to receive an echo signal has been supplied with data, said control means being operative for simultaneously reading out stored data from all of the groups of partial-line digital stores after the time when the group of partial-line digital stores for the last such transducer to receive an echo signal has been supplied with data and before the group of partial line digital stores associated with the first such transducer to receive an echo signal has exceeded its storage capacity.
2. Ultrasonic scanning apparatus according to claim 1, wherein the control means is arranged to produce a signal to enable the said simultaneous reading-out of data from all of the partial-line stores.
3. Ultrasonic scanning apparatus according to claim 2, wherein the said signal is in the form of a pulse.
4. Ultrasonic scanning apparatus according to claim 1, wherein the storage capacity of each partial line store corresponds at least to a maximum delay time before the said last transducer receives an echo signal in use.
5. Ultrasonic scanning apparatus according to claim 4, wherein the storage capacity of each partial-line store is matched to the said maximum delay time, for scanning by pivoting of a beam produced by the ultrasonic scanning apparatus.
6. Ultrasonic scanning apparatus according to claim 1, wherein the minimum storage capacity of each partial-line store is determined by a focus setting time of the ultrasonic scanning apparatus, for dynamic focusing of the apparatus.
7. Ultrasonic scanning apparatus according to claim 6, wherein the storage capacity of each partial-line store, with a delay time of substantially zero before the said last transducer receives an echo signal in use, can be adapted to set the value of the said focus setting time, for purely dynamic focusing of the apparatus.
8. Ultrasonic scanning apparatus according to claim 6, wherein the minimum storage capacity of each partial-line store is also determined by a maximum delay time before the said last transducer receives an echo signal in use.
9. Ultrasonic scanning apparatus according to claim 1, comprising means for processing digital signals.
10. Ultrasonic scanning apparatus according to claim 9, wherein the partial-line stores comprise random access memories.
11. Ultrasonic scanning apparatus according to claim 9, wherein the control means comprises a programmed device.
12. Ultrasonic scanning apparatus according to claim 11, further comprising an address counter associated with the programmed device.
13. Ultrasonic scanning apparatus according to claim 11, further comprising a control pulse generator associated with the programmed device.
14. Ultrasonic scanning apparatus according to claim 11, wherein the control means comprises a further programmed device.
15. Ultrasonic scanning apparatus according to claim 14, with an address counter, associated with each programmed device.
16. Ultrasonic scanning apparatus according to claim 14, further comprising an address adder associated with the further programmed device.
17. Ultrasonic scanning apparatus according to claim 16, wherein the address adder is arranged to control the partial-line stores via an address multiplexer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792942049 DE2942049A1 (en) | 1979-10-17 | 1979-10-17 | DEVICE FOR ULTRASONIC SCANNING |
| DEP2942049.3 | 1979-10-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1168346A true CA1168346A (en) | 1984-05-29 |
Family
ID=6083713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000362599A Expired CA1168346A (en) | 1979-10-17 | 1980-10-16 | Apparatus for ultrasonic scanning |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4373395A (en) |
| EP (1) | EP0027618B1 (en) |
| JP (1) | JPS5673370A (en) |
| AT (1) | ATE4276T1 (en) |
| AU (1) | AU6342280A (en) |
| CA (1) | CA1168346A (en) |
| DE (2) | DE2942049A1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5670758A (en) * | 1979-11-16 | 1981-06-12 | Matsushita Electric Ind Co Ltd | Ultrasonic diagnosis apparatus |
| DE3017027A1 (en) * | 1980-05-02 | 1983-01-20 | Siemens AG, 1000 Berlin und 8000 München | DEVICE FOR STORING SIGNALS |
| DE3020872A1 (en) | 1980-06-02 | 1981-12-10 | Siemens AG, 1000 Berlin und 8000 München | DEVICE FOR ULTRASONIC SCANNING |
| DE3219282C2 (en) * | 1982-05-21 | 1986-09-25 | Siemens AG, 1000 Berlin und 8000 München | Device for ultrasonic scanning according to the pulse-echo method |
| US5143073A (en) * | 1983-12-14 | 1992-09-01 | Edap International, S.A. | Wave apparatus system |
| US5150712A (en) * | 1983-12-14 | 1992-09-29 | Edap International, S.A. | Apparatus for examining and localizing tumors using ultra sounds, comprising a device for localized hyperthermia treatment |
| USRE33590E (en) * | 1983-12-14 | 1991-05-21 | Edap International, S.A. | Method for examining, localizing and treating with ultrasound |
| DE3425705A1 (en) * | 1984-07-12 | 1986-01-16 | Siemens AG, 1000 Berlin und 8000 München | PHASED ARRAY DEVICE |
| DE3428046A1 (en) * | 1984-07-30 | 1986-01-30 | Siemens AG, 1000 Berlin und 8000 München | METHOD AND DEVICE FOR DELAYING AN ULTRASONIC SIGNAL |
| US4799177A (en) * | 1985-12-31 | 1989-01-17 | The Boeing Company | Ultrasonic instrumentation for examination of variable-thickness objects |
| US4799167A (en) * | 1985-12-31 | 1989-01-17 | The Boeing Company | Ultrasonic 64 channel inspection system with multigate/multimode selection software configurability |
| US4809184A (en) * | 1986-10-22 | 1989-02-28 | General Electric Company | Method and apparatus for fully digital beam formation in a phased array coherent imaging system |
| DE8812400U1 (en) * | 1988-09-30 | 1989-04-06 | Siemens Ag, 1000 Berlin Und 8000 Muenchen, De | |
| US5063780A (en) * | 1990-02-15 | 1991-11-12 | General Electric Company | Ultrasonic dimensional and flaw inspection of thin-walled tubular elements |
| US11614890B2 (en) * | 2019-07-30 | 2023-03-28 | Micron Technology, Inc. | Handling of host-initiated requests in memory sub-systems |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4267584A (en) * | 1977-07-01 | 1981-05-12 | Siemens Gammasonics, Inc. | Permutating analog shift register variable delay system |
| US4173007A (en) * | 1977-07-01 | 1979-10-30 | G. D. Searle & Co. | Dynamically variable electronic delay lines for real time ultrasonic imaging systems |
| US4167753A (en) * | 1977-08-18 | 1979-09-11 | General Electric Company | Peak detecting digital scan converter |
| US4159462A (en) * | 1977-08-18 | 1979-06-26 | General Electric Company | Ultrasonic multi-sector scanner |
| EP0002061B2 (en) * | 1977-11-21 | 1986-11-26 | General Electric Company | Scan converter for ultrasonic sector scanner and method |
| US4127034A (en) * | 1977-12-23 | 1978-11-28 | General Electric Company | Digital rectilinear ultrasonic imaging system |
| JPS5499379A (en) * | 1978-01-23 | 1979-08-06 | Tokyo Shibaura Electric Co | Ultrasonic video device |
| US4236221A (en) * | 1978-11-13 | 1980-11-25 | Litton Industrial Products, Inc. | Scan converter |
| US4290310A (en) * | 1979-07-09 | 1981-09-22 | Varian Associates, Inc. | Ultrasonic imaging system using digital control |
| US4245250A (en) * | 1979-09-13 | 1981-01-13 | General Electric Company | Scan converter for ultrasonic sector scanner |
-
1979
- 1979-10-17 DE DE19792942049 patent/DE2942049A1/en not_active Withdrawn
-
1980
- 1980-09-29 US US06/191,779 patent/US4373395A/en not_active Expired - Lifetime
- 1980-10-10 EP EP80106184A patent/EP0027618B1/en not_active Expired
- 1980-10-10 DE DE8080106184T patent/DE3064435D1/en not_active Expired
- 1980-10-10 AT AT80106184T patent/ATE4276T1/en active
- 1980-10-16 JP JP14505480A patent/JPS5673370A/en active Pending
- 1980-10-16 CA CA000362599A patent/CA1168346A/en not_active Expired
- 1980-10-16 AU AU63422/80A patent/AU6342280A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US4373395A (en) | 1983-02-15 |
| ATE4276T1 (en) | 1983-08-15 |
| EP0027618A2 (en) | 1981-04-29 |
| DE3064435D1 (en) | 1983-09-01 |
| EP0027618B1 (en) | 1983-07-27 |
| JPS5673370A (en) | 1981-06-18 |
| AU6342280A (en) | 1981-08-20 |
| DE2942049A1 (en) | 1981-05-21 |
| EP0027618A3 (en) | 1981-10-14 |
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