JP2000254121A - Method and device for forming reception signal and method and device for ultrasonic imaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mitigate the operation condition of the addition means for adding a ΔΣ modulating signal by imparting a delay time by means of imparting a drawing signal to a ΔΣ-modulated signal string in a receiving signal creating method where an added signal is filtered. SOLUTION: ΔΣ modulating circuits 611-615 arranged in a wave reception beam former 610 are disposed at every ultrasonic wave transducer of wave reception apparatus. The circuits 611-615 applies ΔΣ-modulation to the echo signal of an RF(radio frequency) frequency area by over-sampling, which is received by each ultrasonic wave transducer, and convert it into a PCM(pulse code modulation) signal. The output signals of the circuits 611-615 are respectively inputted to delay imparting circuits 621-625. The circuits 621-625 impart a delay corresponding to the direction of an echo reception sound ray and to the focus of echo reception to an input signal and the delay is imparted to a previously fixed PCM signal string.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for forming a received signal and an ultrasonic imaging method and apparatus, and more particularly, to an ultrasonic transducer array (transducc).
er array), a plurality of signals received by Δ
受 信 (delta-sigma) modulation and reception beamforming (beamf) using a plurality of ΔΣ modulated signals
The present invention relates to a method and an apparatus for forming a received signal for performing orchestration, and an ultrasonic imaging method and apparatus using a received signal that has been thus received and beamformed.

[0002]

2. Description of the Related Art As one method of digitally performing ultrasonic receiving beam forming,
There is a method of performing reception beamforming using a ΔΣ modulated signal. This method is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-114.
No. 449, a plurality of signals received by the ultrasonic transducer array are respectively ΔΣ-modulated by a plurality of ΔΣ modulators, and the plurality of signals after the ΔΣ modulation are time-shifted and added. , And the addition result is converted to a decimation filter (decimation filter).
er).

The output signal of the decimation filter forms a received signal for one sound ray. The azimuth and focus of the received beam are determined by the amount of time shift applied to each of the plurality of signals. By changing the time shift amount, the azimuth of the reception beam is changed, and scanning in the order of sound rays is performed.

[0004]

In the above-described receiving beam forming, the focus of the receiving beam (focus: foc)
us) is fixed by the amount of time shift given to the signal, so that the so-called dynamic focus (dynam) that changes the reception focus during signal reception in one direction.
ic focus) cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to realize a reception signal forming method and apparatus and an ultrasonic imaging method and apparatus for performing dynamic focus on a ΔΣ modulation signal. is there.

It is another object of the present invention to realize a reception signal forming method and apparatus, and an ultrasonic imaging method and apparatus, which alleviate the operating conditions of an adding means for adding a ΔΣ modulation signal.

[0007]

Means for Solving the Problems (1) A first aspect of the present invention for solving the above-mentioned problems is that a plurality of ultrasonic transducers constituting an array receive ultrasonic waves, and the plurality of ultrasonic transducers receive the ultrasonic waves. A signal is Δ の -modulated, a predetermined delay time is added to the plurality of ΔΣ-modulated signals, a plurality of signals to which the delay time is added are added, and the added signal is filtered. A method of forming a received signal is characterized in that the delay time is given by giving a stretched signal to a ΔΣ modulated signal sequence.

(2) According to a second aspect of the present invention, an ultrasonic wave is received by a plurality of ultrasonic transducers constituting an array, and a plurality of signals received by the plurality of ultrasonic transducers are ΔΣ modulated. Fourier transform each of the plurality of ΔΣ-modulated signals, apply a predetermined amount of phase shift in the frequency domain to the plurality of Fourier-transformed signals, and convert the plurality of signals with the amount of phase shift in the frequency domain. A method of forming a received signal, comprising adding and performing an inverse Fourier transform on the added signal.

(3) According to a third aspect of the present invention, an ultrasonic wave is received by a plurality of ultrasonic transducers constituting an array, and a plurality of signals received by the plurality of ultrasonic transducers are respectively ΔΣ modulated. A predetermined delay time is added to the plurality of ΔΣ-modulated signals, the plurality of signals to which the delay time is added are respectively filtered, the plurality of filtered signals are added, and the added signal is filtered. This is a method for forming a received signal.

(4) A fourth aspect of the present invention for solving the above-mentioned problems is a plurality of ultrasonic transducers which form an array and receive ultrasonic waves, and a plurality of signals which are received by the plural ultrasonic transducers are ΔΣ modulated. .DELTA..SIGMA. Modulating means, delay time providing means for providing a predetermined delay time to the plurality of .DELTA..SIGMA. Modulated signals, adding means for adding the plurality of signals provided with the delay time, and filtering the added signals. A reception signal forming apparatus having filtering means, wherein the delay time providing means applies a stretched signal to the ΔΣ modulated signal sequence.

(5) A fifth aspect of the present invention for solving the above-mentioned problems is a plurality of ultrasonic transducers that form an array and receive ultrasonic waves, and a plurality of signals received by the plural ultrasonic transducers are ΔΣ modulated. ΔΣ modulating means, Fourier transform means for Fourier transforming each of the plurality of Δ 信号 modulated signals, and a phase shift amount giving means for giving a predetermined phase shift amount in the frequency domain to the Fourier transformed signals, A reception signal forming apparatus comprising: an adding unit that adds a plurality of signals to which the phase shift amount is added in a frequency domain; and an inverse Fourier transform unit that performs an inverse Fourier transform on the added signal.

(6) A sixth aspect of the present invention for solving the above-mentioned problems is a plurality of ultrasonic transducers that form an array and receive ultrasonic waves, and a plurality of signals received by the plural ultrasonic transducers are ΔΣ modulated. .DELTA..SIGMA. Modulating means, delay time means for providing a predetermined delay time to the plurality of .DELTA..SIGMA. Modulated signals, first filtering means for respectively filtering the plurality of signals provided with the delay time, A reception signal forming apparatus comprising: an adding unit that adds a plurality of signals; and a second filtering unit that filters the added signal.

(7) A seventh aspect of the present invention for solving the above-mentioned problems is to transmit an ultrasonic wave, receive an echo of the ultrasonic wave, and form a reception signal along a predetermined sound ray based on the received signal. An ultrasonic imaging method for generating an image based on the formed reception signal, wherein the reception signal is formed by a method according to any one of (1) to (3). This is an ultrasonic imaging method.

(8) According to an eighth aspect of the present invention, there is provided an ultrasonic wave transmitting means for transmitting an ultrasonic wave, a reception signal forming means for forming a reception signal related to the transmitted ultrasonic wave, An ultrasonic imaging apparatus comprising: an image generation unit configured to generate an image based on a signal, wherein the reception signal forming unit according to any one of (4) to (6) is used as the reception signal forming unit. Is an ultrasonic imaging apparatus characterized by using.

In the first invention or the fourth invention, the extended signal is a logical value 1 of the ΔΣ modulated signal.
It is preferable that the signal be a signal of an intermediate level between the signal level corresponding to the logical value 0 and the signal level corresponding to the logical value 0 in order to provide a substantially continuous delay time.

In the first invention or the fourth invention, it is preferable that the extended signal is added to a position in the ΔΣ modulation signal corresponding to a time point at which the signal before modulation becomes 0 level, which is accompanied by filtering. This is preferable in that generation of noise is prevented. In this case, it is preferable that the stretching signal is a signal in which the signal level corresponding to the logical value 1 and the signal level corresponding to the logical value 0 are repeated at the same duty ratio, from the viewpoint of more thorough noise prevention.

(Operation) In the present invention, the signal delay time is adjusted by adjusting the length of the stretched signal to be applied to the ΔΣ-modulated signal sequence, and dynamic focusing is performed. Also, dynamic focus is performed by adjusting the amount of phase shift given in the frequency domain. Further, by filtering in advance before adding a plurality of signals whose delay times have been adjusted, the requirement for increasing the operating speed of the adding means is reduced.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiment. FIG. 1 shows a block diagram of the ultrasonic imaging apparatus. This apparatus is an example of an embodiment of the ultrasonic imaging apparatus of the present invention. The configuration of the present apparatus shows an example of an embodiment relating to the apparatus of the present invention. An example of an embodiment of the method of the present invention is shown by the operation of the present apparatus.

The configuration of the present apparatus will be described. As shown in the figure, the present apparatus has an ultrasonic probe (probe) 2. The ultrasonic probe 2 is used for transmitting and receiving ultrasonic waves while being in contact with the subject 100. The ultrasonic probe 2 has an ultrasonic transducer array (not shown). The ultrasonic transducer array is composed of a plurality of ultrasonic transducers. Each ultrasonic transducer is made of a piezoelectric material such as PZT (lead zirconate titanate (Zr) (Pb)) ceramics.

The ultrasonic probe 2 is connected to a transmitting / receiving unit 6. The transmitting / receiving unit 6 drives the ultrasonic transducer array of the ultrasonic probe 2 to transmit an ultrasonic beam,
Further, the ultrasonic transducer array receives an echo received by the ultrasonic transducer array. FIG. 2 is a block diagram of the transmitting / receiving unit 6.
Shown in As shown in the figure, the transmission / reception unit 6 has a signal generation circuit 602. The signal generation circuit 602 outputs a pulse (pu)
1se) A signal is repeatedly generated at a predetermined cycle and input to the transmission beamformer 606. Transmission beamformer 60
6 generates a transmission beamforming signal based on the input signal. The transmission beam forming signal is a plurality of drive signals applied to a plurality of ultrasound transducers constituting a transmission aperture in the ultrasound transducer array, and each drive signal has a delay time corresponding to the azimuth and focus of the ultrasound beam. Granted. Hereinafter, the transmission aperture is referred to as a transmission aperture.

The transmission beam forming signal is supplied to a plurality of ultrasonic transducers constituting a transmission aperture through a transmission / reception switching circuit 608. Each of the plurality of ultrasonic transducers to which the drive signal is applied generates an ultrasonic wave, and a transmitted ultrasonic beam in a predetermined direction is formed by wavefront synthesis of the ultrasonic waves. The transmitted ultrasonic beam converges on a focal point set at a predetermined distance. Signal generation circuit 6
02, transmission beamformer 606, transmission / reception switching circuit 608
The portion including the ultrasonic probe 2 is an example of the embodiment of the ultrasonic transmitting means in the present invention.

The echo of the transmitted ultrasonic wave is transmitted to the ultrasonic probe 2.
Are received by a plurality of ultrasonic transducers constituting the receiving aperture of the second. Hereinafter, the reception aperture is referred to as a reception aperture. A plurality of echo reception signals received by the plurality of ultrasonic transducers are transmitted and received by a transmission / reception switching circuit 608.
Is input to the receiving beamformer 610 through The reception beamformer 610 adds a delay corresponding to the azimuth of the echo reception sound ray and the focus of the echo reception to each echo reception signal and adds them to form an echo reception signal that matches the predetermined sound ray and focus. I do.

The portion including the ultrasonic probe 2, the transmission / reception switching circuit 608 and the reception beamformer 610 is an example of the embodiment of the reception signal forming apparatus of the present invention. The configuration of this portion shows an example of an embodiment relating to the device of the present invention. The operation of this part shows an example of an embodiment relating to the method of the present invention. Ultrasonic probe 2, transmission / reception switching circuit 608, and reception beam former 61
The portion consisting of zero is also an example of the embodiment of the received signal forming means in the present invention. Receive beamformer 6
10 will be described later.

The transmitting beam former 606 performs sound ray sequential scanning by sequentially switching the direction of the transmitting ultrasonic beam. The receiving beamformer 610 sequentially scans the received sound ray by sequentially switching the direction of the received sound ray. Thereby, the transmission / reception unit 6 performs a scan as shown in FIG. 3, for example. That is, the ultrasonic beam 202 extending in the z direction from the radiation point 200 divides the fan-shaped two-dimensional region 206 by θ.
Scan in the direction, so-called sector scan (sector).
scan).

When the transmitting and receiving apertures are formed by using a part of the ultrasonic transducer array, the apertures are sequentially moved along the array to perform a scanning as shown in FIG. 4, for example. Can be.
That is, as the ultrasonic beam 202 emitted from the radiation point 200 in the z direction moves on the linear trajectory 204, the rectangular two-dimensional area 206 is scanned in the x direction, and a so-called linear scan is performed. Will be

Incidentally, the ultrasonic transducer array is
A so-called convex array (convex array) formed along an arc extending in the ultrasonic wave transmission direction.
In the case of y), the radiation point 200 of the ultrasonic beam 202 moves on an arc-shaped trajectory 204 as shown in FIG. 5, for example, as shown in FIG. Is scanned in the θ direction, so that a so-called convex scan can be performed.

The transmitting / receiving unit 6 includes a data processing unit 8
It is connected to the. In the data processing unit 8, the echo reception signal from the transmission / reception unit 6 is converted into digital data (digital
ldata). The data processing unit 8 processes the input echo data to generate an image. The data processing unit 8 is an example of an embodiment of an image generating unit according to the present invention.

As shown in FIG. 6, the data processing section 8 includes a data processor (processor) 80, an echo memory (echo memory) 82, a data memory 84, and an image memory 86. These are connected by a bus (bus) 88. Transceiver 6
Is input to the echo memory 82. The data processor 80 generates an image based on the echo data.

A display unit 10 is connected to the data processing unit 8. The display unit 10 includes, for example, a graphic display, and the like.
A visible image is displayed based on the image data input from the image memory 86 of the data processing unit 8.

The transmitting / receiving unit 6, the data processing unit 8 and the display unit 10 are connected to the control unit 12. Control unit 12
Supplies a control signal to each of these sections to control the operation thereof. Further, a state notification signal, a response signal, and the like are transmitted from the controlled units to the control unit 12. Ultrasonic imaging is performed under the control of the control unit 12.

An operation unit 14 is connected to the control unit 12. The operation unit 14 is operated by an operator, and the control unit 12
A desired command or information is input to the device. The operation unit 14 includes, for example, an operation panel (panel) including a keyboard and other operation tools.

FIG. 7 is a block diagram showing an example of the receiving beam former 610. As shown in FIG. As shown in the figure, the reception beam former 610 has ΔΣ modulation circuits 611 to 615. Δ
The Σ modulation circuits 611 to 615 are an example of an embodiment of the ΔΣ modulation means in the present invention. ΔΣ modulation circuit 611-
615 is provided for each ultrasonic transducer of the receiving aperture. Here, for convenience of explanation, an example in which the receiving aperture is constituted by five ultrasonic transducers is shown. However, in an actual apparatus, it is usual to constitute about 64 to 128 ultrasonic transducers.

The ΔΣ modulation circuits 611 to 615 transmit RF (radio) signals received by the respective ultrasonic transducers.
frequency) The Δ 信号 modulation of the echo signal in the frequency domain is performed by oversampling, and PCM (pulse code mod)
conversion) signal. ΔΣ modulation circuit 611
615 are input to delay applying circuits 621 to 625, respectively.

The delay giving circuits 621 to 625 give a delay corresponding to the direction of the echo reception sound ray and the focus of the echo reception to the input signal. The delay applying circuits 621 to 625
It is an example of embodiment of the delay time provision means in this invention. To add a delay, a predetermined extended signal
This is performed by adding to the M signal sequence.

Referring to FIG. 8, assuming that a PCM signal as shown in FIG. 8A is obtained, for example, at time A in this signal sequence, as shown in FIG. A signal that does not correspond to either the logical value 1 or the logical value 0, for example, a signal having an intermediate level (level) between the logical value 1 and the logical value 0, that is, a stretching signal is provided. The extension signal may be a signal in which the level of the logical value 1 and the level of the logical value 0 alternate at an appropriate number of times with the same duty ratio as shown in FIG.

As a result, the PCM signal after time A is delayed by the length τ of the stretched signal. The amount of delay can be adjusted by adjusting the length τ of the stretched signal, and an appropriate portion of the PCM signal can be stretched by selecting the point at which the stretched signal is applied.

When the extension signal is given,
As shown in FIG. 9, the input signal of the ΔΣ modulation circuit, that is, the signal before conversion is added to a point corresponding to the time when the 0 level crosses, but the noise (nois) when the signal is filtered by a decimation filter later.
This is preferable in that the occurrence of e) is prevented.

[0038] The extension signal is applied, for example, by temporarily storing the PCM signal in a buffer memory (buffe).
r memory), and an extended signal of an appropriate length is applied to an appropriate portion of the stored signal.

The length [tau] of the stretched signal given by the delay adding circuits 621 to 625 and the time of the addition are determined by the control unit 12 in the direction of the echo reception (steering:
g) and the focal length. Even during the reception of the echo in one direction, the position and the length of the stretched signal can be adjusted, so that the focal length can be changed substantially continuously. That is, continuous dynamic focus can be performed.

The output signals of the delay applying circuits 621 to 625 are input to the adding circuit 630. The addition circuit 630 is an example of an embodiment of an addition unit in the present invention. The adder circuit 630 adds all the input signals. The adder circuit 630 uses P
It is composed of, for example, a digital addition circuit or the like adapted to the CM signal. The output signal of the adding circuit 630 is filtered by the decimation filter 640 to form an echo reception signal for one sound ray.

The decimation filter 640 is an example of the embodiment of the filtering means in the present invention. As the decimation filter 640, a digital decimation filter or an analog (anal)
og) decimation filter is used. When a digital decimation filter is used, an echo reception signal is obtained as digital data. When an analog decimation filter is used, an echo reception signal is obtained as an analog signal.

The extended signal used to add a delay to the PCM signal in the delay applying circuits 621 to 625 is a PCM signal.
Since the signal does not correspond to either the logical value 1 or the logical value 0 of the signal, there is no inconsistency in the filtering performed by the decimation filter 640. Further, setting the position to which the signal is added to the zero cross position of the original signal also contributes to preventing noise generation.

On the other hand, a stretching signal in which a logical value 1 and a logical value 0 alternate at the same duty ratio is a DC (dir)
Since the (ct current) component is 0, there is no inconsistency in the filtering performed by the decimation filter 640, and no noise is generated in combination with the addition of the original signal to the 0 cross position.

As described above, the delay applying circuits 621 to 625
Instead of having both functions of steering and focusing, as shown in FIG.
To 625 are connected in series with shift registers 651 to 655, respectively, and the provision of delay time for steering may be performed by the shift registers 651 to 655.
The delay time is adjusted by switching the output extraction digits in the shift registers 651 to 655. The shift registers 651 to 655 are an example of an embodiment of the time shift means in the present invention.

In this manner, the delay control circuits 621 to 625 can be dedicated to the dynamic focus and the delay control can be simplified. Note that the shift registers 651 to 655 may be placed before the delay applying circuits 621 to 625.

By preliminarily filtering the PCM signal input to the addition circuit 630 to remove high-frequency components to some extent, the high-speed operation required of the addition circuit 630 can be reduced. FIG. 11 shows such an example. As shown in the figure, delay applying circuits 621 to 625
Are input to the adder circuit 630 through the filters 661 to 665, respectively. Filters 661 to 665
Is an example of an embodiment of the first filtering means in the present invention. The addition circuit 630 is an example of an embodiment of the addition means in the present invention. Filter 661-
665 removes the high-frequency component of the signal to the extent that it is compatible with the operation speed of the addition circuit 630. Used.

When the filters 661 to 665 are provided in the preceding stage as described above, the adding circuit 630 can be realized by an analog adding circuit, and the configuration of the adding circuit can be simplified. Of course, even when a digital addition circuit is used, there is an advantage of simplification of the configuration accompanying relaxation of high-speed operation requirements. Also, the decimation filter 640 at the final stage may perform decimation lighter than that shown in FIG. 7 or FIG. The decimation filter 640 is
It is an example of embodiment of the 2nd filtering means in this invention.

When the reception sound ray is steered by a shift register, the filters 661 to 665 are connected to the shift registers 651 to 651, as shown in FIG.
655 output side. FIG. 13 shows a case where the shift registers 651 to 655 are used without performing dynamic focus.
Is an example in which the steering of the reception sound ray is performed.

FIG. 14 is a block diagram showing another example of the receiving beam former 610. As shown in FIG. 7, the same components as those shown in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.
The receiving beamformer 610 is a Fourier (Fourier)
r) It has conversion circuits 711 to 715. The Fourier transform circuits 711 to 715 are an example of an embodiment of the Fourier transform means in the present invention. Fourier transform circuit 711-
Output signals from the ΔΣ modulation circuits 611 to 615 are input to 715.

The Fourier transform circuits 711 to 715 perform Fourier transform on the input signals, respectively, and perform frequency domain (do).
(main) signal. Such a Fourier transform circuit converts, for example, a PCM signal into a digital signal using a decimation filter and converts the signal into an FFT (Fast Fo) signal.
uri Transform circuit, multiple band pass filters
r) a filter bank consisting of parallel circuits
bank), or an FFT circuit specialized for PCM signals.

Output signals of the Fourier transform circuits 711 to 715 are input to phase shift circuits 721 to 725, respectively. The phase shift circuits 721 to 725 are an example of an embodiment of the phase shift amount providing means in the present invention. The phase shift circuits 721 to 725 each apply a phase shift (delay) amount corresponding to the reception sound ray steering and reception focus to the frequency domain signal which is the input signal.

The phase shift amount is controlled by the control unit 12, and the steering of the reception sound ray and the focus of reception are adjusted. By continuously adjusting the amount of phase shift for focus during reception of one sound ray echo, continuous dynamic focus can be performed.

The output signals of the phase shift circuits 721 to 725 are input to the adder 730. The addition circuit 730 is an example of an embodiment of an addition unit in the present invention. The adder circuit 730 performs full addition on the plurality of input signals for each frequency bin in the frequency domain.

The output signal of the adding circuit 730 is input to the inverse Fourier transform circuit 740. Inverse Fourier transform circuit 7
Reference numeral 40 denotes an example of an embodiment of an inverse Fourier transform unit according to the present invention. The inverse Fourier transform circuit 740 includes, for example, iFFT (inverse Fourier Trans)
form) circuit. Inverse Fourier transform circuit 7
40 performs an inverse Fourier transform of the input signal to return to a time-domain signal. The output signal of the inverse Fourier transform circuit 740 is 1
An echo reception signal for a sound ray is formed.

The operation of the present apparatus will be described. The operator contacts the ultrasonic probe 2 with a desired part of the subject 100 and operates the operation unit 14 to perform ultrasonic imaging. Imaging is performed under the control of the control unit 12 based on an instruction from the operator. The transmission / reception unit 6 performs, for example, the sector scan shown in FIG. At that time, the reception focus is continuously adjusted, and echo reception by continuous dynamic focusing is performed.

The data processing section 8 generates, for example, a B-mode image based on the received echo data. Since the echo is received by continuous dynamic focusing, the generated image clearly shows details from the shallow part to the deep part in the body. The generated image is displayed on the display unit 10. Since the display image has a high resolution, accurate diagnosis can be performed.

[0057]

As described above in detail, according to the present invention, it is possible to realize a reception signal forming method and apparatus and an ultrasonic imaging method and apparatus for performing dynamic focusing on a ΔΣ modulation signal. Further, it is possible to realize a reception signal forming method and apparatus, and an ultrasonic imaging method and apparatus, which alleviate the operation conditions of the adding means for adding the ΔΣ modulation signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of a device according to an example of an embodiment of the present invention.

FIG. 2 is a block diagram of a transmission / reception unit in the device shown in FIG.

FIG. 3 is a conceptual diagram of sound ray scanning by the transmission / reception unit shown in FIG. 2;

FIG. 4 is a conceptual diagram of sound ray scanning by the transmission / reception unit shown in FIG. 2;

FIG. 5 is a conceptual diagram of sound ray scanning by the transmission / reception unit shown in FIG. 2;

FIG. 6 is a block diagram of a data processing unit in the device shown in FIG.

FIG. 7 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

FIG. 8 is a graph for explaining delay addition in the receiving beamformer shown in FIG. 7;

FIG. 9 is a graph for explaining delay addition in the receiving beamformer shown in FIG. 7;

FIG. 10 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

FIG. 11 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

FIG. 12 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

FIG. 13 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

FIG. 14 is a block diagram illustrating an example of a reception beam former in the transmission / reception unit illustrated in FIG. 2;

[Explanation of symbols]

 2 ultrasonic probe 6 transmitting / receiving section 8 data processing section 10 display section 12 control section 14 operation section 100 subject 606 transmission beamformer 610 reception beamformer 611-615 ΔΣ modulation circuit 621-625 delay providing circuit 630 addition circuit 640 decimation Filters 651-655 Shift registers 661-665 Filters 711-715 Fourier transform circuits 721-725 Phase shift circuits 730 Adder circuits 740 Inverse Fourier transform circuits

Claims (8)

[Claims] An ultrasonic wave is received by a plurality of ultrasonic transducers constituting an array, a plurality of signals received by the plurality of ultrasonic transducers are respectively ΔΣ-modulated, and a plurality of ΔΣ-modulated signals are predetermined. A reception signal forming method for adding a delay time, adding a plurality of signals to which the delay time has been added, and filtering the added signal, wherein the addition of the delay time extends the signal in the ΔΣ modulated signal sequence. A method for forming a received signal, the method being performed by providing the received signal. 2. An ultrasonic wave is received by a plurality of ultrasonic transducers constituting an array, a plurality of signals received by the plurality of ultrasonic transducers are respectively ΔΣ-modulated, and the plurality of ΔΣ-modulated signals are respectively Fourier-transformed. And applying a predetermined phase shift amount in the frequency domain to the plurality of Fourier-transformed signals, adding the plurality of signals to which the phase shift amount is added in the frequency domain, and performing an inverse Fourier transform on the added signal. A method for forming a received signal. 3. An ultrasonic wave is received by a plurality of ultrasonic transducers constituting an array, a plurality of signals received by the plurality of ultrasonic transducers are respectively ΔΣ-modulated, and the plurality of ΔΣ-modulated signals are predetermined. A method of forming a received signal, comprising: adding a delay time; filtering a plurality of signals to which the delay time is added; adding the plurality of filtered signals; and filtering the added signal. 4. A plurality of ultrasonic transducers forming an array and receiving ultrasonic waves, ΔΣ modulating means for ΔΣ modulating a plurality of signals received by the ultrasonic transducers, and a plurality of ΔΣ modulated signals, respectively. A reception signal forming apparatus, comprising: a delay time providing means for providing a predetermined delay time to, and an adding means for adding a plurality of signals provided with the delay time, and a filtering means for filtering the added signal. The reception signal forming apparatus according to claim 1, wherein the delay time providing means adds a stretched signal to the ΔΣ modulated signal sequence. 5. A plurality of ultrasonic transducers forming an array and receiving ultrasonic waves, ΔΣ modulation means for ΔΣ-modulating a plurality of signals received by the ultrasonic transducers, and a plurality of ΔΣ-modulated signals, respectively. Fourier transform means for respectively performing Fourier transform, a phase shift amount providing means for giving a predetermined phase shift amount in a frequency domain to the plurality of Fourier-transformed signals, and a plurality of signals to which the phase shift amount is given in a frequency domain. And a reverse Fourier transform unit for performing an inverse Fourier transform on the added signal. 6. A plurality of ultrasonic transducers forming an array and receiving ultrasonic waves, ΔΣ modulation means for ΔΣ modulating a plurality of signals received by the ultrasonic transducers, and a plurality of ΔΣ modulated signals, respectively. Delay time means for providing a predetermined delay time to the first, first filtering means for respectively filtering the plurality of signals provided with the delay time, addition means for adding the plurality of filtered signals, And a second filtering means for filtering the signal. 7. An ultrasonic wave transmitting and receiving an echo, forming a received signal along a predetermined sound ray based on the received signal, and generating an image based on the formed received signal. An ultrasonic imaging method, wherein the reception signal is formed by the method according to any one of claims 1 to 3. 8. An ultrasonic transmitting unit for transmitting an ultrasonic wave, a receiving signal forming unit for forming a receiving signal related to the transmitted ultrasonic wave, and an image generating unit for generating an image based on the formed receiving signal. 7. An ultrasonic imaging apparatus comprising: the reception signal forming unit;
An ultrasonic imaging apparatus using the reception signal forming apparatus according to any one of the above.