WO2007039972A1 - Ultrasonograph - Google Patents
Ultrasonograph Download PDFInfo
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- WO2007039972A1 WO2007039972A1 PCT/JP2006/313578 JP2006313578W WO2007039972A1 WO 2007039972 A1 WO2007039972 A1 WO 2007039972A1 JP 2006313578 W JP2006313578 W JP 2006313578W WO 2007039972 A1 WO2007039972 A1 WO 2007039972A1
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- Prior art keywords
- reception
- beamformer
- depth
- delay amount
- ultrasonic
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Classifications
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- 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
-
- 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
- G01S15/8927—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration using a transducer array using simultaneously or sequentially two or more subarrays or subapertures
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- 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
- G01S7/52046—Techniques for image enhancement involving transmitter or receiver
- G01S7/52047—Techniques for image enhancement involving transmitter or receiver for elimination of side lobes or of grating lobes; for increasing resolving power
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
- G10K11/34—Sound-focusing or directing, e.g. scanning using electrical steering of transducer arrays, e.g. beam steering
- G10K11/341—Circuits therefor
- G10K11/346—Circuits therefor using phase variation
Definitions
- the present invention relates to an ultrasonic diagnostic apparatus including an ultrasonic array including a large number of electroacoustic transducers, and more particularly to an ultrasonic diagnostic apparatus having a first reception beamformer and a second reception beamformer.
- Electroacoustic transducers are two-dimensional arrays to measure spatial and temporal four-dimensional ultrasonic echoes, such as measuring three-dimensional blood flow in the coronary arteries of the heart
- a two-dimensional array in which thousands of electroacoustic transducers are arranged.
- the signal obtained from each electroacoustic transducer is subjected to a phasing process for focusing on a certain point in the imaging space by the reception beamformer.
- a receiving beamformer with inputs of several thousand channels is not realistic in terms of equipment scale and cost, it is necessary to reduce the number of channels to about 100 to 200 channels. In this case, it is desirable to use as many electroacoustic transducer signals as possible in order to obtain sufficient received signal power.
- the delay line in the in-group receiving processor is a charge coupled device, analog RAM, sample and hold circuit, active filter, LC filter, and switched capacitor.
- Each of the filters is configured to include one element, and a delay value is provided by a system controller having a digital control circuit.
- Patent Document 1 paragraph 0113, FIG. 3
- the digital data generated by loading the delayed data is Since the weak received signal is buried by the noise, the delay data is loaded only once for each scanning line.
- Patent Document 1 Japanese Patent Laid-Open No. 2000-33087
- the delay amount that can be set in the in-group receiving processor is one set for one scanning line, so depending on the depth of the imaging region
- a large delay amount error occurs with respect to the ideal focus delay amount, and when the grating lobe occurs and the acoustic SZN deteriorates, there is a problem.
- an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of obtaining an ultrasonic image with little deterioration in acoustic SZN with a small delay amount error at each depth of an imaging region!
- An ultrasonic diagnostic apparatus delays reception signals from a plurality of subarrays composed of electroacoustic transducer elements constituting an ultrasonic array and electroacoustic transducers constituting the subarray.
- the fixed delay amount ⁇ ⁇ is determined by the amount of delay ⁇ ⁇ in the first receive beamformer and the delay amount ⁇ in the second mm receive beamformer. It is set so that a clear reception focus beam is formed.
- Depth F is a single ultrasonic transmission m
- reception focus with the smallest delay amount error is possible for the entire imaging region, and deterioration of the acoustic SZN can be minimized and a high-quality ultrasonic image can be obtained.
- FIG. 1 is an apparatus configuration block diagram showing an embodiment of an ultrasonic diagnostic apparatus of the present invention.
- FIG. 2 is a delay amount profile diagram for explaining a delay amount determination method in the first reception beamformer of the present invention.
- FIG. 4 is an apparatus configuration block diagram showing the configuration of the receiving system up to the second receiving beamformer.
- FIG. 5 is an apparatus configuration block diagram showing another embodiment of the first reception beamformer of the present invention.
- FIG. 6 is a configuration diagram of a one-dimensional ultrasonic array.
- FIG. 7 is a beam profile diagram of a one-dimensional ultrasonic array.
- FIG. 8 Envelope extraction of the beam profile of a one-dimensional ultrasonic array.
- FIG. 10 is an operation conceptual diagram showing an example of an ultrasonic diagnostic apparatus according to the present invention. Explanation of symbols
- Transmission amplifier Signal processor
- Second receive beamformer 600 Control unit
- FIG. 1 is an apparatus configuration block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.
- the ultrasonic diagnostic apparatus 1 includes an ultrasonic probe 10 and an apparatus main body 20.
- the ultrasonic probe 10 includes an ultrasonic array 100, a transmission / reception separation switch 21, and a reception amplifier 200 each having a plurality of array element forces.
- the first receiving beamformer 300 and the crosspoint switch 22 are included!
- the ultrasonic array 100 is connected to the transmission / reception separation switch 21, and the transmission / reception separation switch 21 connects the ultrasonic array 100 and the crosspoint switch 22 when transmitting ultrasonic waves, and the ultrasonic array when receiving ultrasonic waves. 100 and receiving amplifier 200 are connected.
- the cross point switch 22 is used as means for selecting which array element the transmission signal from one channel of the transmission beam former 23 is transmitted to.
- the signal from the transmit beamformer 23 during transmission is amplified by the transmission amplifier 24 so as to obtain the desired ultrasonic radiation energy, and transmitted to the ultrasonic array 100 via the crosspoint switch 22 and the transmission / reception separation switch 21. Is done.
- the cross point switch 22 play the role of the transmission / reception separation switch 21.
- a signal received by the ultrasonic array 100 is output to the reception amplifier 200 through the transmission / reception separation switch 21.
- the receiving amplifier 200 may have a TGC (Time Gain Control) function.
- the signal from the reception amplifier 200 is sent to the first reception beamformer 300, and the signal is delayed and added for each subarray obtained by dividing the aperture of the ultrasonic array 100.
- the signal delay in the first receive beamformer is fixed.
- the output of the first receive beamformer 300 is converted into a digital signal by the AD converter 400 and output to the second receive beamformer 500.
- the AD converter 400 may be included in the ultrasonic probe 10.
- second reception beamformer 500 dynamic focus processing is performed, and signals are delayed and added so that reception beams corresponding to the respective depths of the imaging region are formed.
- the input signal is split into a plurality of different delays. In this way, a plurality of reception beams may be formed at the same time, thereby improving the imaging frame rate.
- the output of the second reception beamformer 500 is subjected to desired signal processing by the signal processing unit 25, converted to image information by the display unit 26, and displayed.
- the control unit 600 controls the transmission beam direction, the reception beam direction, the delay amount, the display, and the like.
- the control unit 600 includes an interface for designating the range of the imaging area. For example, when the depth of the imaging area is designated by the user, the control unit 600 gives the first receiving beamformer 300 and the second receiving beamformer 500. An appropriate delay amount is determined and transferred to the first receiving beamformer 300 and the second receiving beamformer 500.
- FIG. 4 is a block diagram showing the configuration of the receiving system from the ultrasound probe 10 to the second receiving beamformer 500 of the ultrasound diagnostic apparatus 1.
- the ultrasonic array 100 includes subarrays 101 to 104, each of which includes four array elements.
- the subarrays 101 to 104 are configured by array elements 111 to 114, 121 to 124, 131 to 134, and 141 to 144, respectively. It is made.
- a signal from the ultrasonic array 100 is output to the reception amplifier 200 by a transmission / reception separation switch 21 (not shown).
- the signals of all the array elements 111 to 144 are amplified by the individual receiving amplifiers 211 to 244, respectively, and output to the first receiving beam former 300.
- the first reception beamformer 300 includes a delay line group 350 including delay lines 311 to 344, a delay amount buffer memory 310 for the delay line group 350, and addition means 301 to 304. ing.
- the outputs of the receiving amplifiers 211 to 244 are given different delay amounts, added for each subarray, AD converted by the AD converters 401 to 404 for each subarray, and output to the second receiving beamformer 500. Is done.
- the signals of the array elements 111 to 114 constituting the subarray 101 are amplified by the receiving amplifiers 211 to 214, given a desired delay by the delay lines 311 to 314, and added by the adding means 301.
- the output signal from the adding means 301 is converted into a digital signal by the AD converter 401 and becomes an input signal per channel of the second reception beamformer 500. Also for subarrays 102-104 Similarly, it becomes an input signal per channel of the second receiving beamformer 500.
- the second reception beamformer 500 includes a delay line group 550 composed of digital delay lines 511 to 514, a delay amount buffer memory 510 for the delay line group 550, and an adding unit 501. ing.
- the control unit 600 calculates an optimal delay amount corresponding to the range of the imaging area, and uses this to calculate the delay amount buffer memory 310 of the first reception beamformer 300 and Transfer to the delay amount buffer memory 510 of the second receive beamformer 500.
- Delay data from the delay amount buffer memory 310 is fixed during reception for one scan line or one transmission, and the delay data is loaded into the delay line group 350 before reception.
- the second reception beamformer dynamic focus processing is performed, and appropriate delays are given by digital delay lines 511 to 514 for each depth.
- FIG. 2 is a delay amount profile of the one-dimensional ultrasonic array showing the relationship between the fixed delay amount in the first receive beamformer and the dynamic delay amount in the second receive beamformer.
- the one-dimensional ultrasonic array 100 is divided into n subarrays 10 n, and each ultrasonic array element of the subarray 10 ⁇ located at X to x is
- the signal is processed by the first receive beamformer 300 and provided to one channel of the second receive beamformer 500. To determine the fixed delay data in the first receive beamformer 300, it is assumed that an ideal receive focus beam is formed at depth F.
- the delay amount ⁇ to be given by the second receive beamformer is determined from the phase center of the subarray 10 ⁇ as follows.
- Equation (2) The amount of delay ⁇ to be given by the form former is as shown in Equation (2).
- the amount of extension is ⁇ + ⁇ ⁇ , and the delay amount profile is shown as curve 12 in FIG. did
- ⁇ is set for all subarrays 10 ⁇ and the depths F to F of the imaging region.
- the integrated function ⁇ of depth F as in the following equation (3) is evaluated for error.
- the depth of the imaging area is F to F, depth F (F ⁇
- al c c is approximated as follows.
- Equation 4 [0027] Substituting equation (4) into equation (3) and executing integration for x and F, the following equation (5) is obtained.
- the aperture L of the one-dimensional ultrasonic array is 19.2 mm
- the number of elements is 64 (element pitch 0.3 mm)
- the frequency is 2.5 MHz
- the sound speed is 1500 mZs
- Figure 3 shows the fixed depth characteristics of the error evaluation function E under the above conditions.
- the horizontal axis is the F number F ZL corresponding to the depth F, and the vertical axis is the error evaluation m m.
- function E is shown on the logarithmic axis.
- Each of the subarrays 801 to 816 is a first receive beamformer that is delayed and added, and the 16 outputs of the first receive beamformer are delayed and added by the second receive beamformer. Processing is performed. The delay given by the first receive beamformer is fixed, and the second receive beamformer performs receive dynamic focus according to the depth.
- the frequency was 2.5 MHz and the sound velocity of the acoustic medium was 1500 mZs.
- FIG. 7 shows a two-dimensional beam profile of the angle and depth of the central force of the one-dimensional array formed by the one-dimensional ultrasonic array 700 of FIG.
- the depth of the imaging area is set to 20 mm to 180 mm
- the delay amount in the first receive beamformer is fixed so that optimum beamforming is performed at a depth of 68 mm
- the scanning line direction is a one-dimensional ultrasonic array. 700 front direction (0 degree direction). From Fig. 7, it can be seen that there are grating lobes in the ⁇ 30 ° and ⁇ 90 ° directions when the depth is shallower and deeper than 68mm.
- the envelope surface of the beam profile as shown in FIG. 7 is extracted.
- the envelope surface of FIG. 7 is shown in FIG. Below, the total acoustic energy P of the envelope as shown in Fig. 8 and the ideal m at each depth
- the acoustic energy difference N P — S from the acoustic energy S of the envelope surface of the beam profile when a smooth focus is performed, and N is defined as acoustic noise.
- FIG. 9 shows a fixed depth F at which the same optimum focus beam as the ideal state is formed by the delay amounts given by the first receive beamformer and the second receive beamformer, It is the fixed depth characteristic figure of the acoustic noise which showed the relationship with noise Nm.
- curves 34 to 38 indicate the depth range F to F (F and F) of the imaging area, 20 mm to 180 mm, respectively.
- the fixed delay amount in the first receive beamformer is such that the depth F force (F + F) / 3 ⁇ F ⁇ (F + F M 1 2 m 1 2) Z2
- the sound velocity setting value is c
- the actual sound of the object to be measured is
- the speed be c + Ac. Also, when the sound speed is c, the focus distance is F.
- the focus distance at 0 0 0 is F + AF.
- the depth F can be finely adjusted within a range of ⁇ 5% of the value.
- the method of determining the delay amount to be given by the second reception beamformer 500 will be described by taking the subarray 101 as an example.
- the first receiving beamformer 300 First, from the minimum value F and the maximum value F of the depth of the imaging range, the first receiving beamformer 300
- the ultrasonic probe is given information on the boundary between the depth that can be regarded as a short distance and the depth that can be regarded as a far distance, and D is the depth of these boundaries.
- the boundary depth D should be chosen so that arcT an (L / 2D) LZ2D is established with an error of 2%, with LZ2 being the half length LZ2 of the ultrasound probe as a representative dimension. ! ⁇ .
- F (F + F) (D ⁇ L) Z (3D ⁇ 2L ⁇ F)
- the optimum depth F is obtained from m 1 2 1 m.
- the received beam is focused at the depth F, and the subarray 101
- the delay amounts ⁇ and ⁇ ′ to be given by the first reception beamformer 300 and the second reception beamformer 500 are obtained.
- an appropriate fixed depth F is selected as described above, and the grating 'lobe' is selected.
- F is transmitted by m times of transmission.
- two delay line groups in the first reception beamformer are connected in series. , First delay line group 360, second delay line group 370, addition means 380, and delay amount buffer memory 310. If the delay amount is fixed for all scanning line directions, and the second delay line group 370 is given a delay amount for changing only the beam direction, the direction for each scanning line is set. The size of delay data to be reduced is reduced, and high-speed imaging and memory saving can be realized.
- the delay line groups 360 and 370 in the first reception beamformer described above are at least one of a charge coupled device, an LC filter, a sample-and-hold circuit, a switched capacitor circuit, and an analog RAM. Consists of two elements.
- the apparatus configuration including the first and second receiving beamformers is 2000 to 3000 like a reception signal having a two-dimensional ultrasonic array power. This is a particularly effective configuration for reducing the number of signals received from the element to 100-200 channels.
- the idea of the present invention and the above-described reception sequence and control are not limited to application to a one-dimensional ultrasonic array, but are also applied to a two-dimensional ultrasonic array.
- FIG. 10 is an operation conceptual diagram showing an example of an ultrasonic diagnostic apparatus according to the present invention.
- the ultrasonic diagnostic apparatus 2 includes an apparatus main body 41, a cable 42, an ultrasonic probe 43, a display 40, and an operation panel 45 for a user to input imaging conditions.
- the ultrasonic probe 43 is applied to the subject 3
- the captured image 50 is displayed on the display screen 44 of the display 40.
- the depth information of the imaging region of the captured image 50 is displayed on the display screen 44 in the imaging depth numerical value display unit 51 and the imaging depth image display unit 52.
- the imaging depth numerical value display section 51 includes a minimum value F and a maximum value F of the depth of the imaging area, and an ultrasonic profile.
- Numerical information of the fixed depth F that determines the delay amount of the first receiving beamformer (not shown) contained in the first 43 beam 43 is displayed.
- the imaging depth image display unit 52 for example, fixed m
- This depth information is displayed graphically, for example, depth information is represented by a fixed depth marker 53.
- the range of the imaging area is, for example, an imaging area selection box 54 displayed on the display screen 44. Can be selected by operating the imaging region selection operation unit 62 or the trackball 63 provided on the operation panel 45.
- the optimal fixed depth F is calculated from the minimum depth F and maximum value F of the imaging area obtained from this, and the ultrasonic wave is calculated.
- the fixed depth F is the fixed depth selection m provided on the operation panel 45.
- the operation unit 61 can be set arbitrarily by the user in a continuous or stepwise manner, thereby setting the delay amount in the first reception beamformer included in the ultrasonic probe 43 and the display screen.
- the depth information represented by the imaging depth numerical display unit 51 and the imaging depth image display unit 52 in 44 is changed following real time.
- the operation of the ultrasonic diagnostic apparatus as described above performs optimum reception focus with respect to the depth of the imaging region, and a high-quality diagnostic image can be obtained with an inexpensive apparatus configuration, and at any depth. It is also possible to display clear images with high resolution.
Abstract
The number of signal channels of an ultrasonic array probe is reduced, and a high-quality image is acquired. An ultrasonic array (100) is divided into sub-arrays. A first reception beamformer (300) delays and adds the reception signals from electro-acoustic conversion elements constituting the sub-arrays . A second reception beamformer (500) delays and adds the output signal of the first reception beamformer by using the output of the first reception beamformer as one channel. During reception for one ultrasonic sound transmission, the delay amount Δτm by the first reception beamformer is fixed, and the second reception beamformer carries out dynamic focus reception. By using the delay amount Δτm by the first reception beamformer and the delay amount τc by the second reception beamformer, an optimal reception focus beam of when the depth of the imaged region is Fm is formed. If the depths of the imaged region for one transmission are F1 to F2, (F1+F2)/3≤Fm≤(F1+F2)/2.
Description
明 細 書 Specification
超音波診断装置 Ultrasonic diagnostic equipment
技術分野 Technical field
[0001] 本発明は、多数の電気音響変換素子から成る超音波アレイを具備する超音波診断 装置に関し、特に第 1の受信ビームフォーマと第 2の受信ビームフォーマとを有する 超音波診断装置に関する。 The present invention relates to an ultrasonic diagnostic apparatus including an ultrasonic array including a large number of electroacoustic transducers, and more particularly to an ultrasonic diagnostic apparatus having a first reception beamformer and a second reception beamformer.
背景技術 Background art
[0002] 心臓の冠状動脈などの 3次元的な血流計測ゃ拍出量の計測など、空間と時間の 4 次元的な超音波エコーを計測するためには、電気音響変換素子を 2次元アレイ状に 配置した探触子が必要であり、所望の分解能を得るために数千個の電気音響変換 素子を配列した 2次元アレイを用いる必要がある。各電気音響変換素子から得られた 信号は、受信ビームフォーマによって撮像空間のある一点にフォーカスするための整 相処理が施される。しかし、数千チャンネルの入力を有する受信ビームフォーマは装 置規模、コスト共に現実的ではないため、 100〜200チャンネル程度にチャンネル数 を低減する必要がある。この場合、十分な受信信号パワーを得るためになるべく多く の電気音響変換素子の信号を用いることが望まし 、。 [0002] Electroacoustic transducers are two-dimensional arrays to measure spatial and temporal four-dimensional ultrasonic echoes, such as measuring three-dimensional blood flow in the coronary arteries of the heart In order to obtain the desired resolution, it is necessary to use a two-dimensional array in which thousands of electroacoustic transducers are arranged. The signal obtained from each electroacoustic transducer is subjected to a phasing process for focusing on a certain point in the imaging space by the reception beamformer. However, since a receiving beamformer with inputs of several thousand channels is not realistic in terms of equipment scale and cost, it is necessary to reduce the number of channels to about 100 to 200 channels. In this case, it is desirable to use as many electroacoustic transducer signals as possible in order to obtain sufficient received signal power.
[0003] そこで、従来、 3000個の超音波アレイ素子を、各々のグループが 25個の素子を含 む 120個のサブアレイにまとめ、グループ内受信プロセッサにより個々の超音波ァレ ィ素子信号を遅延して加算し、加算された信号を受信ビームフォーマのチャンネルの 1つに提供する「グループ内プロセッサを有するフェーズドアレイ音響装置」が提案さ れている(例えば、特許文献 1参照)。 [0003] Therefore, conventionally, 3000 ultrasonic array elements are grouped into 120 subarrays, each group containing 25 elements, and the individual ultrasonic array element signals are delayed by the intra-group receiving processor. In other words, a “phased array acoustic apparatus having an in-group processor” is proposed (see, for example, Patent Document 1) that provides the added signal to one of the channels of the receiving beamformer.
[0004] この「グループ内プロセッサを有するフェーズドアレイ音響装置」では、グループ内 受信プロセッサにおける遅延線は電荷結合素子、アナログ RAM、サンプルアンドホ 一ルド回路、能動フィルタ、 L— Cフィルタ、スィッチドキャパシタフィルタのうち、いず れカ 1つの素子を含んで構成されており、デジタル制御回路を有するシステムコント ローラによって遅延値が提供される。特許文献 1 (段落 0113、図 3)に記載されている ように、遅延データがロードされている間は、遅延データのロードにより生じるデジタ
ルノイズによって微弱な受信信号が埋もれてしまうため、遅延データのロードはそれ ぞれの走査線に対して 1回だけ行っている。 [0004] In this "phased array acoustic device having an in-group processor", the delay line in the in-group receiving processor is a charge coupled device, analog RAM, sample and hold circuit, active filter, LC filter, and switched capacitor. Each of the filters is configured to include one element, and a delay value is provided by a system controller having a digital control circuit. As described in Patent Document 1 (paragraph 0113, FIG. 3), while the delayed data is being loaded, the digital data generated by loading the delayed data is Since the weak received signal is buried by the noise, the delay data is loaded only once for each scanning line.
特許文献 1:特開 2000— 33087号公報 Patent Document 1: Japanese Patent Laid-Open No. 2000-33087
発明の開示 Disclosure of the invention
発明が解決しょうとする課題 Problems to be solved by the invention
[0005] 従来の「グループ内プロセッサを有するフェーズドアレイ音響装置」では、 1つの走 查線に対して、グループ内受信プロセッサにセットできる遅延量が 1組であるため、撮 像領域の深度によっては、理想的なフォーカス遅延量に対して大きな遅延量誤差が 生じるようになり、グレーティング ·ローブが発生して音響 SZNが劣化すると 、う問題 かあつた。 [0005] In the conventional "phased array acoustic apparatus having an in-group processor", the delay amount that can be set in the in-group receiving processor is one set for one scanning line, so depending on the depth of the imaging region However, a large delay amount error occurs with respect to the ideal focus delay amount, and when the grating lobe occurs and the acoustic SZN deteriorates, there is a problem.
[0006] そこで本発明は、撮像領域の各深度において遅延量誤差が小さぐ音響 SZNの 劣化が少な!/、超音波画像を得ることのできる超音波診断装置を提供することを目的 とする。 [0006] Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of obtaining an ultrasonic image with little deterioration in acoustic SZN with a small delay amount error at each depth of an imaging region!
課題を解決するための手段 Means for solving the problem
[0007] 本発明による超音波診断装置は、超音波アレイを構成する電気音響変換素子群か ら構成される複数のサブアレイと、サブアレイを構成する電気音響変換素子からの受 信信号を遅延して加算する第 1の受信ビームフォーマと、第 1の受信ビームフォーマ の出力を 1チャンネルとして、第 1の受信ビームフォーマの出力信号を遅延して加算 する第 2の受信ビームフォーマと、第 1の受信ビームフォーマ及び第 2の受信ビーム フォーマの遅延量を制御する制御部とを具備し、 1回の超音波送信に対する超音波 受信中は第 1の受信ビームフォーマにおける遅延量 Δ τ を固定し、第 2の受信ビー m [0007] An ultrasonic diagnostic apparatus according to the present invention delays reception signals from a plurality of subarrays composed of electroacoustic transducer elements constituting an ultrasonic array and electroacoustic transducers constituting the subarray. The first receive beamformer to add, the second receive beamformer to delay and add the output signal of the first receive beamformer, with the output of the first receive beamformer as one channel, and the first receive A control unit that controls the delay amount of the beamformer and the second reception beamformer, and during the ultrasonic reception for one ultrasonic transmission, the delay amount Δτ in the first reception beamformer is fixed, 2 receiving beam m
ムフォーマでダイナミックフォーカス受信を行う。 Perform dynamic focus reception with a muformer.
[0008] 固定の遅延量 Δ τ は、第 1の受信ビームフォーマにおける遅延量 Δ τ と、第 2の m m 受信ビームフォーマにおける遅延量 τ とによって、撮像領域の深度が Fのときに最 c m 適な受信フォーカスビームが形成されるように設定する。深度 Fは、 1回の超音波送 m [0008] The fixed delay amount Δ τ is determined by the amount of delay Δ τ in the first receive beamformer and the delay amount τ in the second mm receive beamformer. It is set so that a clear reception focus beam is formed. Depth F is a single ultrasonic transmission m
信に対する撮像領域の深度を F〜Fとして、 (F +F ) /3≤F ≤(F +F ) Z2であ (F + F) / 3≤F ≤ (F + F) Z2
1 2 1 2 m 1 2 る。
発明の効果 1 2 1 2 m 1 2 The invention's effect
[0009] 本発明によると、撮像領域全体に対して最も遅延量誤差の小さい受信フォーカスが 可能となり、音響 SZNの劣化を最小限にして、高画質な超音波画像を得ることがで きる。 [0009] According to the present invention, reception focus with the smallest delay amount error is possible for the entire imaging region, and deterioration of the acoustic SZN can be minimized and a high-quality ultrasonic image can be obtained.
図面の簡単な説明 Brief Description of Drawings
[0010] [図 1]本発明の超音波診断装置の一実施例を示す装置構成ブロック図。 FIG. 1 is an apparatus configuration block diagram showing an embodiment of an ultrasonic diagnostic apparatus of the present invention.
[図 2]本発明の第 1受信ビームフォーマにおける遅延量決定方法を説明するための 遅延量プロファイル図。 FIG. 2 is a delay amount profile diagram for explaining a delay amount determination method in the first reception beamformer of the present invention.
[図 3]誤差評価関数の固定深度特性図。 [Fig. 3] Fixed depth characteristics of error evaluation function.
[図 4]超音波探触子力 第 2受信ビームフォーマまでの受信系の構成を示した装置 構成ブロック図。 FIG. 4 is an apparatus configuration block diagram showing the configuration of the receiving system up to the second receiving beamformer.
[図 5]本発明の第 1受信ビームフォーマの別の一実施例を示す装置構成ブロック図。 FIG. 5 is an apparatus configuration block diagram showing another embodiment of the first reception beamformer of the present invention.
[図 6] 1次元超音波アレイの構成図。 FIG. 6 is a configuration diagram of a one-dimensional ultrasonic array.
[図 7] 1次元超音波アレイのビームプロファイル図。 FIG. 7 is a beam profile diagram of a one-dimensional ultrasonic array.
[図 8]1次元超音波アレイのビームプロファイルの包絡面抽出図。 [Fig. 8] Envelope extraction of the beam profile of a one-dimensional ultrasonic array.
[図 9]音響ノイズの固定深度特性図。 [Figure 9] Fixed depth characteristic diagram of acoustic noise.
[図 10]本発明による超音波診断装置の一実施例を示したオペレーション概念図。 符号の説明 FIG. 10 is an operation conceptual diagram showing an example of an ultrasonic diagnostic apparatus according to the present invention. Explanation of symbols
[0011] 1, 2:超音波診断装置 [0011] 1, 2: Ultrasound diagnostic device
3 :被検体 3: Subject
10 :超音波探触子 10: Ultrasonic probe
11〜 13:遅延量プロファイル曲線 11-13: Delay amount profile curve
14 :遅延量誤差面積 14: Delay amount error area
20 :装置本体 20: Main unit
21 :送受分離スィッチ 21: Transmission / reception separation switch
22:クロスポイントスィッチ 22: Crosspoint switch
23 :送信ビームフォーマ 23: Transmitting beamformer
24 :送信アンプ
:信号処理部24: Transmission amplifier : Signal processor
:表示部 : Display section
〜33:誤差評価関数曲線 ~ 33: Error evaluation function curve
:ディスプレイ:display
:装置本体: Main unit
:ケーブル:cable
:超音波プローブ: Ultrasonic probe
:表示画面: Display screen
:操作パネル:control panel
:撮影画像: Image taken
:撮像深度数値表示部: Image depth display
:撮像深度画像表示部: Imaging depth image display
:固定深度マーカー : Fixed depth marker
:撮像領域選択ボックス: Imaging area selection box
:固定深度選択操作部: Fixed depth selection operation section
:撮像領域選択操作部: Imaging area selection operation section
:トラックボール: Trackball
, 700 :超音波アレイ , 700: Ultrasonic array
1〜; 104, 10η, 801〜816:サブアレイ1 to 104, 10η, 801 to 816: Subarray
1〜114, 121〜124, 131〜134, 141〜144, 701〜764:アレイ素子 , 211〜214, 221〜224, 231—234, 241〜244:受信アンプ , 390 :第 1受信ビームフォーマ1-114, 121-124, 131-134, 141-144, 701-764: Array element, 211-214, 221-224, 231-234, 241-244: Receive amplifier, 390: First receive beamformer
, 360, 370, 550:遅延線群 , 360, 370, 550: Delay line group
1〜314, 321〜324, 331〜334, 341〜344, 511〜514:遅延線1〜304, 380, 501 :カロ算手段 1 to 314, 321 to 324, 331 to 334, 341 to 344, 511 to 514: Delay line 1 to 304, 380, 501: Calorie calculation means
, 510 :遅延量バッファメモリ 510: Delay buffer memory
〜404 :AD変換器 ~ 404: AD converter
:第 2受信ビームフォーマ
600 :制御部 : Second receive beamformer 600: Control unit
発明を実施するための最良の形態 BEST MODE FOR CARRYING OUT THE INVENTION
[0012] 以下、図面を参照して本発明の実施の形態を説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013] まず、本発明の超音波診断装置の構成について説明する。図 1は、本発明による 超音波診断装置の一実施例を示す、装置構成ブロック図である。超音波診断装置 1 は、超音波探触子 10と装置本体 20とから構成され、超音波探触子 10は、複数のァ レイ素子力も成る超音波アレイ 100、送受分離スィッチ 21、受信アンプ 200、第 1受 信ビームフォーマ 300、クロスポイントスィッチ 22を含む構成となって!/、る。 First, the configuration of the ultrasonic diagnostic apparatus of the present invention will be described. FIG. 1 is an apparatus configuration block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. The ultrasonic diagnostic apparatus 1 includes an ultrasonic probe 10 and an apparatus main body 20. The ultrasonic probe 10 includes an ultrasonic array 100, a transmission / reception separation switch 21, and a reception amplifier 200 each having a plurality of array element forces. The first receiving beamformer 300 and the crosspoint switch 22 are included!
[0014] 超音波アレイ 100は送受分離スィッチ 21に連結されており、送受分離スィッチ 21は 、超音波送信時には超音波アレイ 100とクロスポイントスィッチ 22とを連結し、超音波 受信時には、超音波アレイ 100と受信アンプ 200とを連結する。クロスポイントスイツ チ 22は、送信ビームフォーマ 23の 1チャンネルからの送信信号を、どのアレイ素子に 伝送するかを選択する手段として用いられる。送信時における送信ビームフォーマ 2 3からの信号は、所望の超音波放射エネルギーが得られるように、送信アンプ 24で 増幅され、クロスポイントスィッチ 22、送受分離スィッチ 21を介して超音波アレイ 100 に伝送される。なお、送受分離スィッチ 21の役割をクロスポイントスィッチ 22で兼ねて ちょい。 [0014] The ultrasonic array 100 is connected to the transmission / reception separation switch 21, and the transmission / reception separation switch 21 connects the ultrasonic array 100 and the crosspoint switch 22 when transmitting ultrasonic waves, and the ultrasonic array when receiving ultrasonic waves. 100 and receiving amplifier 200 are connected. The cross point switch 22 is used as means for selecting which array element the transmission signal from one channel of the transmission beam former 23 is transmitted to. The signal from the transmit beamformer 23 during transmission is amplified by the transmission amplifier 24 so as to obtain the desired ultrasonic radiation energy, and transmitted to the ultrasonic array 100 via the crosspoint switch 22 and the transmission / reception separation switch 21. Is done. In addition, let the cross point switch 22 play the role of the transmission / reception separation switch 21.
[0015] 超音波アレイ 100で受信された信号は、送受分離スィッチ 21を介して受信アンプ 2 00へ出力される。受信アンプ 200は TGC (Time Gain Control)の機能を備えていて もよい。受信アンプ 200からの信号は第 1受信ビームフォーマ 300へ送られ、超音波 アレイ 100の口径を分割してなるサブアレイ毎に、信号が遅延、加算される。 1つの走 查線、あるいは 1回の送信に対する受信中は、第 1受信ビームフォーマでの信号の遅 延量は固定される。第 1受信ビームフォーマ 300の出力は AD変翻 400でデジタル 信号に変換され、第 2受信ビームフォーマ 500に出力される。なお、 AD変換器 400 は、超音波探触子 10の中に含んでもよい。 A signal received by the ultrasonic array 100 is output to the reception amplifier 200 through the transmission / reception separation switch 21. The receiving amplifier 200 may have a TGC (Time Gain Control) function. The signal from the reception amplifier 200 is sent to the first reception beamformer 300, and the signal is delayed and added for each subarray obtained by dividing the aperture of the ultrasonic array 100. During reception for one transmission line or one transmission, the signal delay in the first receive beamformer is fixed. The output of the first receive beamformer 300 is converted into a digital signal by the AD converter 400 and output to the second receive beamformer 500. The AD converter 400 may be included in the ultrasonic probe 10.
[0016] 第 2受信ビームフォーマ 500では、ダイナミックフォーカス処理が行われて、撮像領 域の各深度に応じた受信ビームが形成されるように信号を遅延し、加算する。ここで 第 2受信ビームフォーマでは、入力信号を複数に分岐させて、それぞれ異なる遅延
を与え、同時に複数の受信ビームを形成してもよぐこれによつて撮像のフレームレー トを向上させることができる。 [0016] In second reception beamformer 500, dynamic focus processing is performed, and signals are delayed and added so that reception beams corresponding to the respective depths of the imaging region are formed. Here, in the second receive beamformer, the input signal is split into a plurality of different delays. In this way, a plurality of reception beams may be formed at the same time, thereby improving the imaging frame rate.
[0017] 第 2受信ビームフォーマ 500の出力は、信号処理部 25で所望の信号処理が施され 、表示部 26で画像情報に変換され表示される。送信ビーム方向、受信ビーム方向、 遅延量、表示などの制御は、制御部 600によって行われる。制御部 600は、撮像領 域の範囲を指定するためのインターフェイスを含んでおり、例えばユーザーによって 撮像領域の深度が指定されると、第 1受信ビームフォーマ 300や第 2受信ビームフォ 一マ 500で与えるべき適切な遅延量を決定し、第 1受信ビームフォーマ 300や第 2受 信ビームフォーマ 500に転送する。 The output of the second reception beamformer 500 is subjected to desired signal processing by the signal processing unit 25, converted to image information by the display unit 26, and displayed. The control unit 600 controls the transmission beam direction, the reception beam direction, the delay amount, the display, and the like. The control unit 600 includes an interface for designating the range of the imaging area. For example, when the depth of the imaging area is designated by the user, the control unit 600 gives the first receiving beamformer 300 and the second receiving beamformer 500. An appropriate delay amount is determined and transferred to the first receiving beamformer 300 and the second receiving beamformer 500.
[0018] 次に、本発明の超音波診断装置の受信系について、図面を用いて詳細に説明す る。図 4は、超音波診断装置 1の超音波探触子 10から第 2受信ビームフォーマ 500ま での受信系の構成を示した装置構成ブロック図である。以下では、超音波アレイ 100 を構成するアレイ素子が 16個であるものとする。超音波アレイ 100は、それぞれがァ レイ素子 4個力も構成されるサブアレイ 101〜104からなり、サブアレイ 101〜104は 、それぞれアレイ素子 111〜114、 121~124, 131〜134、 141〜144によって構 成されている。受信時においては、図示しない送受分離スィッチ 21によって、超音波 アレイ 100の信号が受信アンプ 200へ出力される。すべてのアレイ素子 111〜144 の信号は、個別の受信アンプ 211〜244でそれぞれ増幅され、第 1受信ビームフォ 一マ 300へ出力される。 Next, the reception system of the ultrasonic diagnostic apparatus of the present invention will be described in detail with reference to the drawings. FIG. 4 is a block diagram showing the configuration of the receiving system from the ultrasound probe 10 to the second receiving beamformer 500 of the ultrasound diagnostic apparatus 1. In the following, it is assumed that there are 16 array elements constituting the ultrasonic array 100. The ultrasonic array 100 includes subarrays 101 to 104, each of which includes four array elements. The subarrays 101 to 104 are configured by array elements 111 to 114, 121 to 124, 131 to 134, and 141 to 144, respectively. It is made. At the time of reception, a signal from the ultrasonic array 100 is output to the reception amplifier 200 by a transmission / reception separation switch 21 (not shown). The signals of all the array elements 111 to 144 are amplified by the individual receiving amplifiers 211 to 244, respectively, and output to the first receiving beam former 300.
[0019] 第 1受信ビームフォーマ 300は、遅延線 311〜344を含む遅延線群 350と、遅延線 群 350のための遅延量バッファメモリ 310と、加算手段 301〜304とを含んで構成さ れている。受信アンプ 211〜244の各出力は、それぞれ異なる遅延量が与えられて 、サブアレイ毎に加算され、 AD変換器 401〜404によって各サブアレイ毎に AD変 換されて、第 2受信ビームフォーマ 500へ出力される。例えば、サブアレイ 101を構成 するアレイ素子 111〜114の信号は、受信アンプ 211〜214で増幅された後、遅延 線 311〜314で所望の遅延が与えられ、加算手段 301で加算される。加算手段 301 からの出力信号は、 AD変換器 401でデジタル信号に変換されて、第 2受信ビームフ ォーマ 500の 1チャンネルあたりの入力信号となる。サブアレイ 102〜104に関しても
同様にして、第 2受信ビームフォーマ 500の 1チャンネルあたりの入力信号となる。 The first reception beamformer 300 includes a delay line group 350 including delay lines 311 to 344, a delay amount buffer memory 310 for the delay line group 350, and addition means 301 to 304. ing. The outputs of the receiving amplifiers 211 to 244 are given different delay amounts, added for each subarray, AD converted by the AD converters 401 to 404 for each subarray, and output to the second receiving beamformer 500. Is done. For example, the signals of the array elements 111 to 114 constituting the subarray 101 are amplified by the receiving amplifiers 211 to 214, given a desired delay by the delay lines 311 to 314, and added by the adding means 301. The output signal from the adding means 301 is converted into a digital signal by the AD converter 401 and becomes an input signal per channel of the second reception beamformer 500. Also for subarrays 102-104 Similarly, it becomes an input signal per channel of the second receiving beamformer 500.
[0020] 第 2受信ビームフォーマ 500は、デジタル遅延線 511〜514で構成される遅延線群 550と、遅延線群 550のための遅延量バッファメモリ 510と、加算手段 501とを含んで 構成されている。 The second reception beamformer 500 includes a delay line group 550 composed of digital delay lines 511 to 514, a delay amount buffer memory 510 for the delay line group 550, and an adding unit 501. ing.
[0021] 撮像領域の範囲が設定されると、制御部 600は、その撮像領域の範囲に応じた最 適な遅延量を計算し、これを第 1受信ビームフォーマ 300の遅延量バッファメモリ 310 と第 2受信ビームフォーマ 500の遅延量バッファメモリ 510に転送する。遅延量バッフ ァメモリ 310からの遅延データは 1つの走査線あるいは 1回の送信に対する受信中は 固定されており、受信前に遅延線群 350に遅延データがロードされる。第 2受信ビー ムフォーマでは、ダイナミックフォーカス処理が施され、深度毎に適切な遅延がデジタ ル遅延線 511〜514で与えられる。 [0021] When the range of the imaging area is set, the control unit 600 calculates an optimal delay amount corresponding to the range of the imaging area, and uses this to calculate the delay amount buffer memory 310 of the first reception beamformer 300 and Transfer to the delay amount buffer memory 510 of the second receive beamformer 500. Delay data from the delay amount buffer memory 310 is fixed during reception for one scan line or one transmission, and the delay data is loaded into the delay line group 350 before reception. In the second reception beamformer, dynamic focus processing is performed, and appropriate delays are given by digital delay lines 511 to 514 for each depth.
[0022] 次に、撮像領域の深度とグループ内受信プロセッサに与える遅延量との最適条件 について検討する。図 2は、第 1の受信ビームフォーマにおける固定遅延量と、第 2 の受信ビームフォーマにおけるダイナミック遅延量との関係を示した、 1次元超音波 アレイの遅延量プロファイルである。 1次元超音波アレイ 100は、 n個のサブアレイ 10 nに分割されており、 X 〜x に位置するサブアレイ 10ηの各超音波アレイ素子からの Next, the optimum condition between the depth of the imaging area and the amount of delay given to the intra-group reception processor will be examined. FIG. 2 is a delay amount profile of the one-dimensional ultrasonic array showing the relationship between the fixed delay amount in the first receive beamformer and the dynamic delay amount in the second receive beamformer. The one-dimensional ultrasonic array 100 is divided into n subarrays 10 n, and each ultrasonic array element of the subarray 10η located at X to x is
nl n2 nl n2
信号は、第 1の受信ビームフォーマ 300で処理されて、第 2の受信ビームフォーマ 50 0の 1チャンネルに提供される。第 1の受信ビームフォーマ 300における固定の遅延 データを決定するために、深度 Fで理想的な受信フォーカスビームを形成すると仮 The signal is processed by the first receive beamformer 300 and provided to one channel of the second receive beamformer 500. To determine the fixed delay data in the first receive beamformer 300, it is assumed that an ideal receive focus beam is formed at depth F.
m m
定すると、その遅延量 Δ τ のプロファイルは曲線 11のようになる。深度 Fに対して As a result, the profile of the delay amount Δ τ is as shown in curve 11. For depth F
ideal m ideal m
、第 2の受信ビームフォーマで与えるべき遅延量 Δ τ は、サブアレイ 10ηの位相中 心から次のように求められる。 The delay amount ∆τ to be given by the second receive beamformer is determined from the phase center of the subarray 10η as follows.
[数 1] [Number 1]
Arc = arg[ I &χρ[~ ίωΑτί(ΐ6αΙ]ώ ここで、 iは虚数単位、 ωは超音波の角周波数である。したがって、第 1の受信ビー ムフォーマで与えるべき固定の遅延量 Δ τ は、 Δ τ = Δ τ - Δ τ と求められる
[0024] 次に、深度 Fで理想的な受信フォーカスビームを形成することを考えると、その遅延 量 τ のプロファイルは曲線 13のようになる。深度 Fの場合と同様に、第 2の受信ビ ideal m Ar c = arg [I & χρ [~ ίωΑτ ί (ΐ6αΙ ] ώ where i is the imaginary unit and ω is the angular frequency of the ultrasound. Therefore, the fixed delay amount to be given by the first receiving beamformer Δ τ Is obtained as Δ τ = Δ τ-Δ τ Next, considering that an ideal reception focus beam is formed at a depth F, the profile of the delay amount τ is as shown by a curve 13. As with depth F, the second receiver
ームフォーマで与えるべき遅延量 τ は、式 (2)のようになる。 The amount of delay τ to be given by the form former is as shown in Equation (2).
[数 2] ー(2) [Equation 2] ー (2)
[0025] 先に求めた第 1の受信ビームフォーマにおける遅延量 Δ τ とあわせて、実際の遅 [0025] In addition to the delay amount Δτ in the first receive beamformer obtained earlier, the actual delay
m m
延量は τ + Δ τ となり、遅延量プロファイルは図 2の曲線 12のように示される。した The amount of extension is τ + Δ τ, and the delay amount profile is shown as curve 12 in FIG. did
c m cm
がって、理想的な遅延量との誤差は Therefore, the error from the ideal delay amount is
τ ~ { τ + Δ τ ) = ( τ Δ τ )— ( τ — Δ τ ) τ ~ (τ + Δ τ) = (τ Δ τ) — (τ — Δ τ)
ideal c m ideal ideal c c ideal c m ideal ideal c c
となり、この誤差が大きいとサブアレイ間の誤差も大きぐグレーティング 'ローブ発生 の原因になる。そこで、図 2の斜線で示される Δ Θ領域 14の面積の大きさを音響 SZ Νの劣化に影響を与えるパラメータとして、全てのサブアレイ 10η、及び撮像領域の 深度 F 〜Fに対して Δ Θを積分した、次式 (3)のような深度 Fの関数 Εを、誤差評価 Therefore, if this error is large, the error between subarrays is large, which causes the generation of grating lobes. Therefore, using the size of the area of the ΔΘ region 14 shown by the diagonal lines in FIG. 2 as a parameter that affects the degradation of the acoustic SZΝ, ΔΘ is set for all subarrays 10η and the depths F to F of the imaging region. The integrated function の of depth F as in the following equation (3) is evaluated for error.
1 2 n m 1 2 n m
関数として定義する。 Define as a function.
[数 3] [Equation 3]
= L l f Ί (て ' - AT^OI ) - {TC - ATC ) \dxdF … (3) [0026] 音響 SZNの劣化を最小にする深度 Fを求めるには、 dE/dF =0となる深度 Fを = L lf Ί (Te '- AT ^ OI) - { T C - The AT C) \ dxdF ... (3 ) [0026] obtaining depth F to minimize the degradation of the acoustic SZN, and dE / dF = 0 Depth F
m m m 求めればよい。問題を簡単にするために、撮像領域の深度を F 〜F、深度 F (F < m m m To simplify the problem, the depth of the imaging area is F to F, depth F (F <
1 2 m l 1 2 ml
F < F )が十分遠方にあるとして、いずれの深度に対しても位相中心の値に対する m 2 M 2 for the value of the phase center at any depth, assuming that F <F) is far enough
座標 Xが X (X < x < x )にあると仮定する。音速を cとすれば、遅延量て , Δ τ Suppose the coordinate X is in X (X <x <x). If the speed of sound is c, the amount of delay is ∆τ
c nl c n2 0 ideal me c nl c n2 0 ideal me
, τ , Δ τ , τ, Δ τ
al c cはそれぞれ以下のように近似される。 al c c is approximated as follows.
[数 4]
[0027] 式 (4)を式 (3)に代入し、 x, Fについての積分を実行すると次式 (5)が得られる。 [Equation 4] [0027] Substituting equation (4) into equation (3) and executing integration for x and F, the following equation (5) is obtained.
[数 5] ,,)= ^ , , ) '∑g( > ^nl, Xc ) f{Fm, ) = 2 (log Fm - \)+ - log F、 F2 [Equation 5] ,,) = ^,,) '∑g (> ^ nl, X c) f {F m ,) = 2 (log F m- \) + -log F, F 2
r m r m
,ズ ,,2 , x ) = ~- {(^i ÷ )(3 ~ xn 2 l + xnlx„2 } … ,, ,, 2 , x ) = ~-{(^ i ÷) (3 ~ x n 2 l + x nl x „ 2 }…
[0028] 次に、式 (5)で表される深度 Fと誤差評価関数 Eとの関係を調べるために行ったシミ m [0028] Next, a stain m performed to examine the relationship between the depth F represented by Equation (5) and the error evaluation function E
ユレーシヨン結果について、図 3を用いて説明する。シミュレーションは、 1次元超音 波アレイの口径 Lを 19. 2mm、素子数を 64 (素子ピッチ 0. 3mm)、周波数を 2. 5M Hz、音速を 1500mZs、撮像領域の深度 F〜Fを Fナンバーで 1〜9 (F = 19. 2m The results of the urasion will be described with reference to FIG. In the simulation, the aperture L of the one-dimensional ultrasonic array is 19.2 mm, the number of elements is 64 (element pitch 0.3 mm), the frequency is 2.5 MHz, the sound speed is 1500 mZs, and the imaging area depth F to F is F number. 1 ~ 9 (F = 19.2m
1 2 1 m、F = 172. 8mm)として、 1次元超音波アレイを 8個、 16個、 32個のサブアレイに 1 2 1 m, F = 172.8 mm), 1D ultrasonic array into 8, 16, 32 subarrays
2 2
それぞれ分割した場合を仮定した。図 3は、上記条件における誤差評価関数 Eの固 定深度特性図であり、横軸は深度 Fに対応する Fナンバー F ZL、縦軸は誤差評価 m m The case where each was divided was assumed. Figure 3 shows the fixed depth characteristics of the error evaluation function E under the above conditions. The horizontal axis is the F number F ZL corresponding to the depth F, and the vertical axis is the error evaluation m m.
関数 Eの値を対数軸上に示している。図中、実線 31〜33はサブアレイが 8個、 16個 、 32個の場合の結果をそれぞれ示している。図 3のシミュレーション結果から、誤差 評価関数 Eの最小値は F ZL = 5付近のときであり、サブアレイの数が少ないと若干 m The value of function E is shown on the logarithmic axis. In the figure, solid lines 31 to 33 show the results when there are 8, 16, and 32 subarrays, respectively. From the simulation results in Fig. 3, the minimum value of the error evaluation function E is around F ZL = 5, and it is slightly m when the number of subarrays is small.
高くなること、 F /L > 3では、誤差評価関数 Eの値は低く抑えられることがわかる。 It can be seen that when F / L> 3, the error evaluation function E can be kept low.
m m
[0029] 以上の結果から、誤差評価関数 Eは深度 Fに関して、下に凸の曲線関係となって m [0029] From the above results, the error evaluation function E becomes a convex curve relationship with respect to the depth F, m
おり、上述の深度 Fの最適値は、式 (5)を用いて、 dEZdF The optimum value of the depth F described above is expressed by dEZdF using equation (5).
m m =0、すなわち dfZdF m m m = 0, ie dfZdF m
=0となる深度 Fを求めればよぐ結果として F = (F +F Finding the depth F at which = 0 results in F = (F + F
m m 1 2 )Z2が最適値として得ら れる。したがって、撮像領域の深度 F〜F (F >F )が超音波アレイよりも充分遠方に m m 1 2) Z2 is obtained as the optimum value. Therefore, the depth F to F (F> F) of the imaging area is far enough from the ultrasonic array.
1 2 2 1 1 2 2 1
ある場合、第 1の受信ビームフォーマにおける固定の遅延量は、 F = (F +F In some cases, the fixed amount of delay in the first receive beamformer is F = (F + F
m 1 2 )Z2と なる深度 Fで最適な受信フォーカスビームが形成されるように決定すればょ 、こと力 S m m 1 2) If it is determined that an optimal receive focus beam is formed at a depth F of Z2, the force S m
明らかになった。 It was revealed.
[0030] 上述の結果は、撮像領域の深度 F〜F (F >F )が超音波アレイよりも充分遠方に [0030] The above results indicate that the depth F to F (F> F) of the imaging region is sufficiently far from the ultrasonic array.
1 2 2 1 1 2 2 1
ある場合の結果であり、また、グレーティング 'ローブの強度を直接評価したものでは ない。そこで以下では、撮像領域の深度が浅いところにある場合も含めて、グレーテ
イング ·ローブを直接評価したシミュレーション結果について、図 6〜図 9を用いて説 明する。 This is a result of some cases and is not a direct evaluation of the intensity of the grating 'lobe. Therefore, in the following, including the case where the depth of the imaging area is shallow, The simulation results of direct evaluation of the ing lobes are explained using Figs.
[0031] シミュレーションにおいては、図 6に示すような、 64個の点音源状の素子 701〜76 4 (素子ピッチ 0. 3mm、アレイ寸法 L= 18. 9mm)からなる 1次元アレイ 700を考え、 隣り合う 4素子で一つのサブアレイを構成し、全 16サブアレイ 801〜816で構成され ているものとした。各サブアレイ 801〜816は、第 1の受信ビームフォーマで、それぞ れ遅延、加算処理が行なわれ、第 1の受信ビームフォーマ力もの 16個の出力は、第 2の受信ビームフォーマで遅延、加算処理が行なわれる。第 1の受信ビームフォーマ で与えられる遅延量は固定とし、第 2の受信ビームフォーマでは深度に応じた受信ダ イナミックフォーカスを行なうものとする。また、周波数を 2. 5MHz,音響媒質の音速 を 1500mZsとした。 In the simulation, a one-dimensional array 700 composed of 64 point sound source-like elements 701 to 76 4 (element pitch 0.3 mm, array dimension L = 18.9 mm) as shown in FIG. It is assumed that one subarray is composed of four adjacent elements, and that all 16 subarrays 801 to 816 are composed. Each of the subarrays 801 to 816 is a first receive beamformer that is delayed and added, and the 16 outputs of the first receive beamformer are delayed and added by the second receive beamformer. Processing is performed. The delay given by the first receive beamformer is fixed, and the second receive beamformer performs receive dynamic focus according to the depth. The frequency was 2.5 MHz and the sound velocity of the acoustic medium was 1500 mZs.
[0032] 図 7は、図 6の 1次元超音波アレイ 700が形成する、 1次元アレイの中央力もの角度 と深度との 2次元ビームプロファイルを示したものである。図 7においては、撮像領域 の深度を 20mm〜180mmとして、深度 68mmにおいて最適なビームフォーミングが なされるように、第 1の受信ビームフォーマにおける遅延量を固定し、走査線方向は 1 次元超音波アレイ 700の正面方向(0度方向)である。図 7から、深度が 68mmより浅 い場合及び深い場合において、 ± 30度方向、 ± 90度方向にグレーティング 'ローブ が生じていることがわかる。 FIG. 7 shows a two-dimensional beam profile of the angle and depth of the central force of the one-dimensional array formed by the one-dimensional ultrasonic array 700 of FIG. In Fig. 7, the depth of the imaging area is set to 20 mm to 180 mm, the delay amount in the first receive beamformer is fixed so that optimum beamforming is performed at a depth of 68 mm, and the scanning line direction is a one-dimensional ultrasonic array. 700 front direction (0 degree direction). From Fig. 7, it can be seen that there are grating lobes in the ± 30 ° and ± 90 ° directions when the depth is shallower and deeper than 68mm.
[0033] 上記グレーティング 'ローブを音響ノイズとして定義するために、まず、図 7で示した ようなビームプロファイルの包絡面を抽出する。図 7の包絡面は図 8のように示される 。以下では、図 8のような包絡面の全音響エネルギー Pと、各深度において理想的 m In order to define the grating lobe as acoustic noise, first, the envelope surface of the beam profile as shown in FIG. 7 is extracted. The envelope surface of FIG. 7 is shown in FIG. Below, the total acoustic energy P of the envelope as shown in Fig. 8 and the ideal m at each depth
なフォーカスが行なわれたときのビームプロファイルの包絡面の音響エネルギー Sと の音響エネルギー差 N =P — Sを計算し、 Nを音響ノイズとして定義する。 The acoustic energy difference N = P — S from the acoustic energy S of the envelope surface of the beam profile when a smooth focus is performed, and N is defined as acoustic noise.
m m m m m m
[0034] 図 9は、第 1の受信ビームフォーマと第 2の受信ビームフォーマとで与えられた遅延 量によって、理想状態と同じ最適なフォーカスビームが形成される固定深度 Fと、上 m 記音響ノイズ Nmとの関係を示した、音響ノイズの固定深度特性図である。図中、曲 線 34〜38は、撮像領域の深度範囲 F〜F (Fく F )を、それぞれ 20mm〜 180mm [0034] FIG. 9 shows a fixed depth F at which the same optimum focus beam as the ideal state is formed by the delay amounts given by the first receive beamformer and the second receive beamformer, It is the fixed depth characteristic figure of the acoustic noise which showed the relationship with noise Nm. In the figure, curves 34 to 38 indicate the depth range F to F (F and F) of the imaging area, 20 mm to 180 mm, respectively.
1 2 1 2 1 2 1 2
、 20mm〜150mm、 40mm〜l20mm、 100mm〜180mm、 160mm〜l80mm
とした場合に相当する。 1次元超音波アレイ力もの距離が充分遠方とみなせる曲線 3 6〜38においては、図 3で示した結果同様、ほぼ F = (F +F 20mm ~ 150mm, 40mm ~ l20mm, 100mm ~ 180mm, 160mm ~ l80mm It corresponds to the case. In the curve 3 6 to 38 where the distance of one-dimensional ultrasonic array force can be regarded as far away, similar to the result shown in Fig. 3, F = (F + F
m 1 2 )Z2が、固定深度の 最適値となっているが、曲線 34, 35のように撮像領域が充分遠方とみなせない領域 を含む場合においては、固定深度の最適値は F = (F +F )Z3程度となる。ここで m 1 2 m 1 2) Z2 is the optimum value for the fixed depth, but when the imaging area includes areas that cannot be considered far away as shown by curves 34 and 35, the optimum value for the fixed depth is F = (F + F) Z3 or so. Where m 1 2
充分遠方とは、 1次元アレイの半分の寸法 LZ2と撮像領域の深度の最小値 Fとの関 Sufficiently far is the relationship between the half dimension LZ2 of the one-dimensional array and the minimum depth F of the imaging area.
1 係が arcTan(LZ2F ) =L/2Fとなることに相当し、図 6に示した 1次元超音波ァレ 1 is equivalent to arcTan (LZ2F) = L / 2F, and the one-dimensional ultrasonic array shown in Fig. 6
1 1 1 1
ィ 700の場合には、 F≥40mmにおいて、約 2%以内の誤差で arcTan(LZ2F ) =L In the case of 700, arcTan (LZ2F) = L with an error of about 2% at F≥40mm
1 1 1 1
/2Fが成り立つ。 / 2F holds.
1 1
[0035] 以上のことから、撮像領域の深度の最小値 Fが充分遠方とみなせない浅いところに [0035] Because of the above, in a shallow place where the minimum depth F of the imaging area cannot be considered far enough
1 1
あり、撮像領域の深度の最小値 Fが充分遠方にあるとみなせる場合には、第 1の受 Yes, if the minimum depth F of the imaging area can be considered far enough, the first receiving
2 2
信ビームフォーマにおける固定の遅延量は、 F = (F +F )Z3となる深度 Fで最適 m 1 2 m な受信フォーカスビームが形成されるように決定すればょ 、。 The fixed amount of delay in the beamformer can be determined so that an optimum focus beam of m 1 2 m is formed at a depth F where F = (F + F) Z3.
[0036] したがって、図 3に示した結果も含めると、第 1の受信ビームフォーマにおける固定 の遅延量は、深度 F力 (F +F)/3≤F ≤ (F +F の範囲となるようにして決 m 1 2 m 1 2 )Z2 [0036] Therefore, including the results shown in Fig. 3, the fixed delay amount in the first receive beamformer is such that the depth F force (F + F) / 3≤F ≤ (F + F M 1 2 m 1 2) Z2
定すればよぐ特に浅いところ力 深いところまで撮像する場合は F = (F +F)/3 m 1 2 If the image is taken to a deep location, F = (F + F) / 3 m 1 2
、充分深いところを撮像する場合は F = (F +F F = (F + F
m 1 2 )Z2とすればよい。 m 1 2) Z2.
[0037] 以上の結果は、被測定物の音速を 1500mZsで一定として得られたものであり、被 測定物が均質で、音速がほぼ一定の場合に適用される。しかし、被測定物が例えば 生体であると、生体組織の種類によって、その音速は(1560 ±70) mZs程度の幅を 持つ。したがって、式 (4)に示したような遅延時間を計算するとき、設定した音速から定 まるフォーカス距離と、実際のフォーカス距離とに誤差を生じることを考慮する必要が ある。 The above results are obtained when the sound speed of the object to be measured is constant at 1500 mZs, and is applied when the object to be measured is homogeneous and the sound speed is substantially constant. However, if the object to be measured is a living body, for example, the speed of sound has a width of about (1560 ± 70) mZs depending on the type of living tissue. Therefore, when calculating the delay time as shown in Equation (4), it is necessary to take into account that an error occurs between the focus distance determined from the set sound speed and the actual focus distance.
[0038] 本発明の超音波診断装置において、音速の設定値を cとし、実際の被測定物の音 [0038] In the ultrasonic diagnostic apparatus of the present invention, the sound velocity setting value is c, and the actual sound of the object to be measured is
0 0
速が c + Acであるとする。また、音速を cとしたときのフォーカス距離を Fとし、実際 Let the speed be c + Ac. Also, when the sound speed is c, the focus distance is F.
0 0 0 のフォーカス距離を F + AFとする。このとき、上記設定値から求まる遅延時間と実際 The focus distance at 0 0 0 is F + AF. At this time, the delay time obtained from the set value and the actual
0 0
の遅延時間は等しいから、 Fc = (F +AF) (c + Ac)の関係式が成り立つ。この関 Since the delay times are equal, the relational expression Fc = (F + AF) (c + Ac) holds. This
0 0 0 0 0 0 0 0
係式から、 AF/F =一(AcZc)Z(l+AcZc)が得られる。上述のように、例え From the equation, AF / F = 1 (AcZc) Z (l + AcZc) is obtained. As mentioned above,
0 0 0 0 0 0
ば生体組織の音速が(1560±70)mZsであるとすれば、 c =1560m/s, Ac二士
70mZsとすると、 I A F/F | ≤4. 3%となる。実際には、異なる組織を音波が伝 For example, if the speed of sound of living tissue is (1560 ± 70) mZs, c = 1560m / s, Ac Assuming 70mZs, IAF / F | ≤4.3.3%. In practice, sound waves propagate through different tissues.
0 0
播する際に生じる屈折などの影響も考慮し、 I A F/F | ≤ 5%程度とすることが望 Considering the effects of refraction, etc. that occur during sowing, it is desirable that I A F / F | ≤ 5%
0 0
ましい。 Good.
[0039] 以上の結果から、上述した第 1の受信ビームフォーマにおける固定の遅延量を決 定するための深度 Fを求めた後、その値の ± 5%の幅で深度 Fを微調整できるよう [0039] From the above results, after obtaining the depth F for determining the fixed delay amount in the first reception beamformer described above, the depth F can be finely adjusted within a range of ± 5% of the value.
m m m m
にすることが、実用上望ましい。 It is desirable for practical use.
[0040] 次に、撮像範囲の深度 F〜Fが与えられた場合に、第 1受信ビームフォーマ 300 [0040] Next, when the imaging range depths F to F are given, the first reception beamformer 300
1 2 1 2
及び第 2受信ビームフォーマ 500で与えるべき遅延量の決定方法につ 、て、サブァ レイ 101を例に述べる。 The method of determining the delay amount to be given by the second reception beamformer 500 will be described by taking the subarray 101 as an example.
[0041] まず、撮像範囲の深度の最小値 Fと最大値 Fとから、第 1受信ビームフォーマ 300 First, from the minimum value F and the maximum value F of the depth of the imaging range, the first receiving beamformer 300
1 2 1 2
で与えられる固定の遅延量を決定するための深度 Fを、(F +F ) /3≤F ≤(F + Depth F to determine the fixed delay given by (F + F) / 3 ≤ F ≤ (F +
m 1 2 m l m 1 2 m l
F )Z2の範囲で求める。ここで、深度 Fを求める際のアルゴリズムについて説明するF) Calculated within the range of Z2. Here, I will explain the algorithm for finding the depth F
2 m 2 m
。まず、超音波探触子には、近距離とみなせる深度と充分遠方とみなせる深度との境 界の情報が与えられており、これらの境界の深度を Dとする。境界の深度 Dは、例え ば、超音波探触子の口径 Lの半分の長さ LZ2を代表寸法として、 2%の誤差で arcT an (L/2D) LZ2Dが成り立つような値を選べば良!ヽ。 . First, the ultrasonic probe is given information on the boundary between the depth that can be regarded as a short distance and the depth that can be regarded as a far distance, and D is the depth of these boundaries. For example, the boundary depth D should be chosen so that arcT an (L / 2D) LZ2D is established with an error of 2%, with LZ2 being the half length LZ2 of the ultrasound probe as a representative dimension. !ヽ.
[0042] まず、撮像領域の深度 F〜Fの最小値 Fが F≥Dである場合には、 F = (F +F [0042] First, when the minimum value F of the imaging region depth F to F is F≥D, F = (F + F
1 2 1 1 m 1 2 1 2 1 1 m 1 2
)Z2とする。撮像領域の深度 F〜Fの最小値 Fが口径と等しく(Fナンバーが ) Let Z2. Depth of imaging area F to F Minimum value F is equal to aperture (F number is
1 2 1 1)、 F 1 2 1 1), F
1 1
=Lである場合には、 F = (F +F ) Z3とする。 Lく Fく Dの範囲にある場合には、 When = L, F = (F + F) Z3. If it is in the range of L く F く D,
m 1 2 1 m 1 2 1
例えば、 L< F < Dの間で (F +F ) /3< F < (F +F ) For example, between L <F <D (F + F) / 3 <F <(F + F)
1 1 2 m 1 2 Z2の関係式を直線補間し 1 1 2 m 1 2 Z2
、F = (F +F ) (D— L)Z(3D— 2L— F )の関係式から、最適な深度 Fが求められ m 1 2 1 m る。 F = (F + F) (D−L) Z (3D−2L−F) The optimum depth F is obtained from m 1 2 1 m.
[0043] 次に、アレイ素子 111〜 114について、深度 Fで理想的な受信フォーカスビームが [0043] Next, with respect to the array elements 111 to 114, an ideal reception focus beam is obtained at the depth F.
m m
形成されるとした場合の遅延量 Δ τ を求め、その中で最も小さい遅延量を Δ τ ideal min とする。これより、第 1受信ビームフォーマ 300内の遅延線 311〜314に与えるべき遅 延量 Δ τ は、 Δ τ = Δ τ —Δ τ として求まる。 The amount of delay Δτ when it is formed is obtained, and the smallest amount of delay is Δτ ideal min. From this, the delay amount Δτ to be given to the delay lines 311 to 314 in the first reception beamformer 300 is obtained as Δτ = Δτ−Δτ.
m m ideal min m m ideal min
[0044] 次に、サブアレイ 101を構成するアレイ素子 111〜114に同じ遅延量 Δ τ を与え て加算したときに、深度 Fで受信ビームがフォーカスされるものとし、サブアレイ 101 Next, when the same delay amount Δ τ is given to the array elements 111 to 114 constituting the subarray 101 and added, the received beam is focused at the depth F, and the subarray 101
m
に関して式 (1)を用いて遅延量 Δ τ を求める。さらに、 Δ τ と Δ τ との差 Δ τ = Δ m For Eq. (1), the delay amount Δ τ is obtained. Furthermore, the difference between Δ τ and Δ τ Δ τ = Δ
c c min a τ - Δ τ を求める。 c c min a τ-Δ τ is obtained.
c min c min
[0045] 撮像領域の深度 Fのデータを取得する場合、第 2受信ビームフォーマ 500ではダイ ナミックフォーカス処理が行われる。すなわち、第 2受信ビームフォーマ 500内の遅延 線 511で与える遅延量は次のようにして求められる。まず、サブアレイ 101を構成す るアレイ素子 111〜114に同じ遅延量 τ を与えて加算したときに、深度 Fで受信ビー ムがフォーカスされるものとし、サブアレイ 101に関して式 (2)を用いて遅延量 τ を求 める。遅延量 τ と前記 Δ τ から、遅延線 511で与えるべき遅延量 τ 'が τ ' = τ — Δ τ として求まる。他の全てのサブアレイ 102〜104についても同様の計算方法 d [0045] When acquiring data of depth F of the imaging region, the second reception beamformer 500 performs a dynamic focus process. That is, the delay amount given by the delay line 511 in the second reception beamformer 500 is obtained as follows. First, when the same delay amount τ is given to the array elements 111 to 114 constituting the subarray 101 and added, the received beam is focused at the depth F, and the delay for the subarray 101 is calculated using Equation (2). Find the quantity τ. From the delay amount τ and Δτ, the delay amount τ ′ to be given by the delay line 511 is obtained as τ ′ = τ−Δτ. Similar calculation method for all other subarrays 102-104 d
によって、第 1受信ビームフォーマ 300及び第 2受信ビームフォーマ 500で与えるベ き遅延量 Δ τ 及び τ 'を求める。 Thus, the delay amounts Δτ and τ ′ to be given by the first reception beamformer 300 and the second reception beamformer 500 are obtained.
m c m c
[0046] 以上のようにして、深度 Fに受信ビームを形成すると、撮像領域の深度が充分遠方 にある場合には、図 2における曲線 12のような遅延データが与えられたことになる。 曲線 12は深度 F = (F +F ) Z2として求められているので、前述したように深度 Fに As described above, when the reception beam is formed at the depth F, when the depth of the imaging region is sufficiently far away, the delay data as shown by the curve 12 in FIG. 2 is given. Curve 12 is determined as depth F = (F + F) Z2, so we have
m 1 2 m 1 2
理想的な受信フォーカスビームが形成される遅延データの曲線 13との差異が最も小 さく抑えられている。したがって、撮像領域の深度 F〜Fにおいてグレーティング '口 The difference from the curve 13 of the delay data that forms the ideal receive focus beam is minimized. Therefore, at the depth F to F of the imaging area, the grating 'mouth
1 2 1 2
ーブの影響を最小限に抑えることができる。同様に、撮像領域の深度が浅いところも 含む場合にも、上述のように適切な固定深度 Fが選択され、グレーティング 'ローブ The influence of the probe can be minimized. Similarly, even when the imaging area includes a shallow depth, an appropriate fixed depth F is selected as described above, and the grating 'lobe' is selected.
m m
の影響を最小限に抑えることができる。 Can be minimized.
[0047] また、撮像領域の深度の最小値 F と最大値 F に対して、 m回の送信によって F [0047] Further, for the minimum value F and the maximum value F of the depth of the imaging region, F is transmitted by m times of transmission.
min max min min max min
〜F のデータを収集する場合には、例えば m回の送信で F 〜F 全体が撮像で max min max When collecting data of ~ F, for example, when F is sent m times, the whole image of F ~ F is max min max
きるように、 1回の送信における撮像領域の深度 F〜Fを決定し、上述の方法により To determine the depth F to F of the imaging area in one transmission and
1 2 1 2
、 m組の F〜Fに対して遅延線群 350で固定する遅延量 Δ て をそれぞれ求めれば If the delay amount Δ fixed by the delay line group 350 is obtained for m sets of F to F, respectively,
1 2 m 1 2 m
よい。 Good.
[0048] また、上記 m組の各組において発生するグレーティング 'ローブの方向は異なるた め、 1組の F〜Fに対して固定される Δ τ を用いて F 〜F までのデータを収集し [0048] Further, since the direction of the grating lobe generated in each of the m sets is different, data from F to F is collected using Δτ fixed to one set of F to F.
1 2 m min max 1 2 m min max
、これを全ての組の F〜Fに対して行って、全ての収集データをカ卩算してもよい。 This may be done for all sets of FF to count all collected data.
1 2 1 2
[0049] また、図 5に示すように、第 1受信ビームフォーマ内の遅延線群を 2段直列に連結し
、第 1の遅延線群 360、第 2の遅延線群 370、加算手段 380、遅延量バッファメモリ 3 10とから構成した第 1受信ビームフォーマ 390を用い、第 1の遅延線群 360で与える べき遅延量は、全ての走査線方向に対して固定とし、第 2の遅延線群 370ではビー ム方向のみを変化させるための遅延量を与えるようにすれば、各走査線に対して口 ードすべき遅延データの大きさが小さくなり、高速な撮像と省メモリ化が実現できる。 In addition, as shown in FIG. 5, two delay line groups in the first reception beamformer are connected in series. , First delay line group 360, second delay line group 370, addition means 380, and delay amount buffer memory 310. If the delay amount is fixed for all scanning line directions, and the second delay line group 370 is given a delay amount for changing only the beam direction, the direction for each scanning line is set. The size of delay data to be reduced is reduced, and high-speed imaging and memory saving can be realized.
[0050] なお、上述の第 1受信ビームフォーマにおける遅延線群 360, 370は、電荷結合素 子、 L—Cフィルタ、サンプルアンドホールド回路、スィッチドキャパシタ回路、アナ口 グ RAMのうち、少なくとも 1つの素子を含んで構成する。 [0050] Note that the delay line groups 360 and 370 in the first reception beamformer described above are at least one of a charge coupled device, an LC filter, a sample-and-hold circuit, a switched capacitor circuit, and an analog RAM. Consists of two elements.
[0051] 上述の実施例は、 1次元超音波アレイを対象としていたが、第 1及び第 2受信ビー ムフォーマを有する装置構成は、 2次元超音波アレイ力もの受信信号のように、 2000 〜3000素子からの受信信号数を、 100〜200チャンネルの信号数に低減するため に特に有効な構成である。本発明の思想や上述の受信シーケンス、制御についても 、 1次元超音波アレイへの適用に限定されるものではなぐ 2次元超音波アレイにも適 用される。 [0051] Although the above-described embodiment is intended for a one-dimensional ultrasonic array, the apparatus configuration including the first and second receiving beamformers is 2000 to 3000 like a reception signal having a two-dimensional ultrasonic array power. This is a particularly effective configuration for reducing the number of signals received from the element to 100-200 channels. The idea of the present invention and the above-described reception sequence and control are not limited to application to a one-dimensional ultrasonic array, but are also applied to a two-dimensional ultrasonic array.
[0052] 以上のような構成および制御のもと行なわれる超音波診断時のオペレーションの具 体例について、図面を用いて説明する。 A specific example of the operation at the time of ultrasonic diagnosis performed under the configuration and control as described above will be described with reference to the drawings.
[0053] 図 10は、本発明による超音波診断装置の一実施例を示したオペレーション概念図 である。超音波診断装置 2は装置本体 41と、ケーブル 42と、超音波プローブ 43と、 ディスプレイ 40と、ユーザーが撮像条件を入力するための操作パネル 45とから構成 されている。被検体 3に超音波プローブ 43を当てると、ディスプレイ 40の表示画面 44 に撮影画像 50が映し出される。この時、表示画面 44には、撮像画像 50の撮像領域 の深度情報が撮像深度数値表示部 51と撮像深度画像表示部 52に表示される。撮 像深度数値表示部 51には、撮像領域の深度の最小値 F、最大値 F、超音波プロ FIG. 10 is an operation conceptual diagram showing an example of an ultrasonic diagnostic apparatus according to the present invention. The ultrasonic diagnostic apparatus 2 includes an apparatus main body 41, a cable 42, an ultrasonic probe 43, a display 40, and an operation panel 45 for a user to input imaging conditions. When the ultrasonic probe 43 is applied to the subject 3, the captured image 50 is displayed on the display screen 44 of the display 40. At this time, the depth information of the imaging region of the captured image 50 is displayed on the display screen 44 in the imaging depth numerical value display unit 51 and the imaging depth image display unit 52. The imaging depth numerical value display section 51 includes a minimum value F and a maximum value F of the depth of the imaging area, and an ultrasonic profile.
1 2 一 ブ 43に内包された図示しない前記第 1の受信ビームフォーマの遅延量を決定する固 定深度 Fの数値情報が表示されており、撮像深度画像表示部 52では、例えば固定 m Numerical information of the fixed depth F that determines the delay amount of the first receiving beamformer (not shown) contained in the first 43 beam 43 is displayed. In the imaging depth image display unit 52, for example, fixed m
深度の情報を固定深度マーカー 53によって表すなど、これらの深度情報がグラフィ カルに表示される。 This depth information is displayed graphically, for example, depth information is represented by a fixed depth marker 53.
[0054] 撮像領域の範囲は、例えば、表示画面 44に映し出された撮像領域選択ボックス 54
を、操作パネル 45に設けられた撮像領域選択操作部 62やトラックボール 63によって 操作して選択することができる。撮像領域の範囲が指定されると、これより得られる撮 像領域の深度の最小値 F、最大値 Fから、最適な固定深度 Fが計算され、超音波 [0054] The range of the imaging area is, for example, an imaging area selection box 54 displayed on the display screen 44. Can be selected by operating the imaging region selection operation unit 62 or the trackball 63 provided on the operation panel 45. When the range of the imaging area is specified, the optimal fixed depth F is calculated from the minimum depth F and maximum value F of the imaging area obtained from this, and the ultrasonic wave is calculated.
1 2 m 1 2 m
プローブ 43に内包された第 1の受信ビームフォーマにおける遅延量が設定されて、 撮像が行われる。また、固定深度 Fは、操作パネル 45に設けられた固定深度選択 m A delay amount in the first reception beamformer included in the probe 43 is set, and imaging is performed. The fixed depth F is the fixed depth selection m provided on the operation panel 45.
操作部 61によって、ユーザーが連続的あるいはステップ的に任意に設定することも でき、これによつて超音波プローブ 43に内包された第 1の受信ビームフォーマにおけ る遅延量の設定や、表示画面 44内の撮像深度数値表示部 51と撮像深度画像表示 部 52で表される深度情報は、リアルタイムに追随して変更される。 The operation unit 61 can be set arbitrarily by the user in a continuous or stepwise manner, thereby setting the delay amount in the first reception beamformer included in the ultrasonic probe 43 and the display screen. The depth information represented by the imaging depth numerical display unit 51 and the imaging depth image display unit 52 in 44 is changed following real time.
以上のような、超音波診断装置のオペレーションによって、撮像領域の深度に対し て最適な受信フォーカスが行われ、安価な装置構成で、高画質な診断画像が得られ ると共に、任意の深度に対して分解能の高い鮮明な画像を表示することも可能にな る。
The operation of the ultrasonic diagnostic apparatus as described above performs optimum reception focus with respect to the depth of the imaging region, and a high-quality diagnostic image can be obtained with an inexpensive apparatus configuration, and at any depth. It is also possible to display clear images with high resolution.
Claims
[1] 電気音響変換素子群から構成される複数のサブアレイと、 [1] A plurality of subarrays composed of electroacoustic transducer elements,
前記サブアレイを構成する複数の電気音響変換素子力 の受信信号を遅延してカロ 算する第 1の受信ビームフォーマと、 A first receive beamformer that delays and calorizes received signals of a plurality of electroacoustic transducer elements constituting the sub-array;
前記第 1の受信ビームフォーマの出力を 1チャンネルとして、前記第 1の受信ビーム フォーマの出力信号を遅延して加算する第 2の受信ビームフォーマと、 A second receive beamformer that delays and adds the output signal of the first receive beamformer with the output of the first receive beamformer as one channel;
前記第 1の受信ビームフォーマ及び前記第 2の受信ビームフォーマの遅延量を制 御する制御部とを具備し、 A control unit that controls a delay amount of the first reception beamformer and the second reception beamformer;
1回の超音波送信に対する超音波受信中は前記第 1の受信ビームフォーマにおけ る遅延量 Δ τ を固定して前記第 2の受信ビームフォーマでダイナミックフォーカス受 During ultrasonic reception for one ultrasonic transmission, the delay amount Δτ in the first reception beamformer is fixed and dynamic focus reception is performed by the second reception beamformer.
m m
信を行うことを特徴とする超音波診断装置。 An ultrasonic diagnostic apparatus characterized by performing communication.
[2] 請求項 1に記載の超音波診断装置において、前記第 1の受信ビームフォーマにお ける遅延量 Δ τ と、前記第 2の受信ビームフォーマにおける遅延量 τ とによって、 [2] In the ultrasonic diagnostic apparatus according to claim 1, the delay amount Δτ in the first reception beamformer and the delay amount τ in the second reception beamformer,
m c m c
撮像領域の深度が Fのときに最適な受信フォーカスビームが形成されるように前記 In order to form an optimal receive focus beam when the depth of the imaging area is F
m m
遅延量 Δ τ を設定することを特徴とする超音波診断装置。 An ultrasonic diagnostic apparatus characterized by setting a delay amount Δτ.
m m
[3] 請求項 1に記載の超音波診断装置において、 1回の超音波送信に対する撮像領 域の深度を F〜F (F >F )として、 (F +F ) /3≤F ≤ (F +F ) Z2であることを特 [3] The ultrasonic diagnostic apparatus according to claim 1, wherein the depth of the imaging area for one ultrasonic transmission is F to F (F> F), and (F + F) / 3≤F ≤ (F + F) Z2
1 2 2 1 1 2 m 1 2 1 2 2 1 1 2 m 1 2
徴とする超音波診断装置。 Ultrasound diagnostic device to be a sign.
[4] 請求項 1に記載の超音波診断装置にお!、て、前記システム制御部は、撮像領域の 深度の最小値 F及び最大値 F、あるいは撮像領域の入力を受けて、前記第 1の受 [4] In the ultrasonic diagnostic apparatus according to claim 1, the system control unit receives the input of the minimum value F and maximum value F of the depth of the imaging region or the imaging region, and Receipt of
1 2 1 2
信ビームフォーマにおける遅延量 Δ τ を計算することを特徴とする超音波診断装置 An ultrasonic diagnostic apparatus characterized by calculating a delay amount Δτ in a transmission beamformer
m m
[5] 請求項 1に記載の超音波診断装置において、 1つの走査線における全撮像領域の 深度 F 〜F に対して複数回 (m回)の超音波ビームを送信し、各送信に対する撮 min max [5] The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic beam is transmitted a plurality of times (m times) to the depths F to F of the entire imaging region in one scanning line, and the imaging min is performed for each transmission. max
像領域の深度 F 〜F を変化させ、各深度 F 〜F に対する前記遅延量 Δ τ を変 By changing the depth F to F of the image area, the delay amount Δτ for each depth F to F is changed.
lm 2m lm 2m m 化させて撮像することを特徴とする超音波診断装置。 lm 2m lm 2m m Ultrasonic diagnostic equipment characterized by imaging.
[6] 請求項 1に記載の超音波診断装置において、 1つの走査線における全撮像領域の 深度 F 〜F に対して複数回 (m回)の超音波ビームを送信し、各送信に対して前
記遅延量 Δ τ を変化させて撮像し、前記第 1の受信ビームフォーマと前記第 2の受 m [6] The ultrasonic diagnostic apparatus according to claim 1, wherein an ultrasonic beam is transmitted a plurality of times (m times) to the depths F to F of the entire imaging region in one scanning line, and for each transmission in front The delay time Δ τ is changed for imaging, and the first reception beamformer and the second reception m
信ビームフォーマとによって、前記全撮像領域の深度 F 〜F に対する受信ビーム Receive beam for the depths F to F of the entire imaging area
min max min max
を各送信に対して形成し、 1つの走査線に対する m個の前記受信ビームを加算して 、前記走査線上の前記全撮像領域の深度 F 〜F に対する受信ビームを形成する Is formed for each transmission, and the m received beams for one scan line are added to form a receive beam for the depths F to F of the entire imaging region on the scan line.
min max min max
ことを特徴とする超音波診断装置。 An ultrasonic diagnostic apparatus.
請求項 1に記載の超音波診断装置において、前記第 1の受信ビームフォーマは、 全走査線に対し固定の遅延量を与える第 1の遅延線と、 1つの走査線に対して、角 度成分のみを与える第 2の遅延線とを含んで構成されることを特徴とする超音波診断 装置。
2. The ultrasonic diagnostic apparatus according to claim 1, wherein the first reception beamformer includes: a first delay line that gives a fixed delay amount to all scanning lines; and an angular component for one scanning line. And a second delay line for providing only an ultrasonic diagnostic apparatus.
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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DK200800633A (en) * | 2008-05-02 | 2009-05-23 | Bk Medical Aps | Method and apparatus for processing ultrasonic signals |
WO2014182567A1 (en) * | 2013-05-08 | 2014-11-13 | General Electric Company | Ultrasound probe with dynamic focus and associated systems and methods |
US9134419B2 (en) | 2010-06-23 | 2015-09-15 | Kabushiki Kaisha Toshiba | Ultrasonic diagnosis apparatus |
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JPH01195844A (en) * | 1988-01-29 | 1989-08-07 | Yokogawa Medical Syst Ltd | Ultrasonic wave receiving phasing circuit |
JPH07313509A (en) * | 1994-05-24 | 1995-12-05 | Fujitsu Ltd | Ultrasonic wave receiving method and device therefor |
JP2001104303A (en) * | 1999-10-04 | 2001-04-17 | Aloka Co Ltd | Ultrasonograph |
-
2006
- 2006-07-07 WO PCT/JP2006/313578 patent/WO2007039972A1/en active Application Filing
- 2006-07-07 JP JP2007538647A patent/JP4599408B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH01195844A (en) * | 1988-01-29 | 1989-08-07 | Yokogawa Medical Syst Ltd | Ultrasonic wave receiving phasing circuit |
JPH07313509A (en) * | 1994-05-24 | 1995-12-05 | Fujitsu Ltd | Ultrasonic wave receiving method and device therefor |
JP2001104303A (en) * | 1999-10-04 | 2001-04-17 | Aloka Co Ltd | Ultrasonograph |
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Publication number | Priority date | Publication date | Assignee | Title |
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DK200800633A (en) * | 2008-05-02 | 2009-05-23 | Bk Medical Aps | Method and apparatus for processing ultrasonic signals |
US9134419B2 (en) | 2010-06-23 | 2015-09-15 | Kabushiki Kaisha Toshiba | Ultrasonic diagnosis apparatus |
WO2014182567A1 (en) * | 2013-05-08 | 2014-11-13 | General Electric Company | Ultrasound probe with dynamic focus and associated systems and methods |
US9239375B2 (en) | 2013-05-08 | 2016-01-19 | General Electric Company | Ultrasound probe with dynamic focus and associated systems and methods |
CN105339808A (en) * | 2013-05-08 | 2016-02-17 | 通用电气公司 | Ultrasound probe with dynamic focus and associated systems and methods |
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