JP6579231B2 - Ultrasonic image generation method and ultrasonic diagnostic apparatus - Google Patents

Description

  The present disclosure relates to an ultrasonic signal processing apparatus and an ultrasonic diagnostic apparatus using the same, and more particularly, to a beam forming process in the ultrasonic signal processing apparatus.

  The ultrasonic diagnostic apparatus transmits an ultrasonic wave inside a subject using an ultrasonic probe (hereinafter referred to as “probe”), and receives an ultrasonic reflected wave (echo) generated by a difference in acoustic impedance of the subject tissue. Furthermore, an ultrasonic tomographic image showing the structure of the internal tissue of the subject is generated based on the electrical signal obtained from this reception, and displayed on a monitor (hereinafter referred to as “display unit”). An ultrasonic diagnostic apparatus is widely used for morphological diagnosis of a living body because it hardly invades a subject and can observe a state of a body tissue in real time with a tomographic image or the like.

In a conventional ultrasonic diagnostic apparatus, a method generally called a phasing addition method is used as a reception beam forming method of a signal based on a received reflected ultrasonic wave (echo signal) (for example, Non-Patent Document 1). .
FIG. 16 is a schematic diagram showing a reception beamforming method in a conventional ultrasonic diagnostic apparatus. The conventional ultrasonic diagnostic apparatus includes a probe 201 including a plurality of ultrasonic transducers 201a (hereinafter referred to as “vibrators”) that receive reflected ultrasonic waves from the body of a subject, and a reflected ultrasonic wave received by the transducers 201a. A reception beamformer unit 202 is provided that performs phasing addition processing after a sound wave is electrically converted into an electric signal, the analog electric signal is amplified and A / D converted into a digital signal. The reception beamformer unit 202 is associated with each transducer 201a, and apodizes the output signals from the delay unit 2021 and the delay units 2021 that perform amplification processing, A / D conversion processing, and delay processing on the electric signal. And an adding unit 2022 for adding by multiplying the weights. The reception beamformer unit 202 performs the delay process by the delay unit 2021 for each transducer 201a on the electrical signal based on the reflected ultrasonic wave obtained by the transducer 201a, and adds the result obtained by the addition unit 2022 as an acoustic line signal. Output. At this time, the delay amount applied by the delay unit 2022 is generally calculated based on the distance between the observation point located on the central axis of the transmission ultrasonic beam and each transducer 201a.

Specifically, P is an arbitrary observation point located on the central axis of the transmitted ultrasonic beam in the subject, d _c is the distance between the transducer C closest to the observation point P and the observation point P, and the observation point P If the distance from the other transducer m is d _m , and the sound velocity of the ultrasonic wave is cs, it is delayed (d _m / cs−d _c / cs) from the time when the reflected wave from the observation point P reaches the transducer c. At the same time, the reflected wave from the observation point P reaches the vibrator m. The arrival time of the reflected wave to the transducer c can be calculated for the observation point P having an arbitrary depth, and the arrival time of the reflected wave at the transducer m can be derived from the arrival time difference between the transducers. The delay unit 2021 identifies reception signals in each transducer taking the arrival time difference into account, and the addition unit 2022 adds the identified reception signals to generate an acoustic line signal.

Masatoshi Ito and Tsuyoshi Mochizuki, “Ultrasound Diagnostic Device”, Corona Publishing, August 26, 2002 (P42-P45) "Virtual ultrasound sources in high resolution ultrasound imaging", S.I.Nikolov and J.A.Jensen, in Proc, SPIE − Progress in biomedical optics and imaging, vol. 3, 2002, P. 395-405

  However, in the reception beamforming method described in Non-Patent Document 1, the resolution is high and the image quality is high and the noise is further suppressed in the vicinity of the transmission focus point where the radiated ultrasonic waves gather at a certain depth in the subject. An ultrasonic image can be obtained. On the other hand, there has been a problem that it is difficult to obtain a high-quality image in the ultrasonic irradiation region away from the vicinity of the transmission focus point.

  The present invention has been made in view of the above problems, and an ultrasonic signal processing apparatus capable of generating a high-quality ultrasonic image with high resolution and reduced noise over the entire ultrasonic irradiation region, and ultrasonic waves using the same An object is to provide a diagnostic apparatus.

An ultrasonic diagnostic apparatus according to an aspect of the present invention includes an ultrasonic probe having a plurality of transducers, and a transmission unit that performs ultrasonic transmission from a first transducer array that corresponds to all or part of the plurality of transducers. And a reception signal sequence for each transducer of the second transducer array is generated according to a signal based on the reflected ultrasonic wave obtained by the second transducer array corresponding to all or part of the plurality of transducers. A receiving unit, a delay amount generating unit that generates a plurality of delay amounts corresponding to the plurality of transducers, a delay processing unit that delays a received signal sequence for each transducer based on the plurality of delay amounts, has the delay amount generation unit, in one transmission event, for one observation point you located within the ultrasonic wave transmitted arrives, the transmitted ultrasonic wave is before Symbol one observation A transmission that generates a transmission time until the point is reached Comprising as between generating unit, and a reception time generation unit for generating a reception time reflected ultrasonic wave to reach each of the transducers in the second oscillator column from the previous SL one observation point, generating the transmission time said transmission time generated by parts, based on said reception time of each transducer of said second oscillator string generated by the reception time generation unit, each vibration Doko of the second oscillator column The transmission time generation unit generates the transmission time as data shared between the transducers of the second transducer array.

  According to the ultrasonic signal processing apparatus and the ultrasonic diagnostic apparatus using the ultrasonic signal processing apparatus according to one aspect of the present invention, a high-quality ultrasonic image with higher resolution and lower noise than the conventional one is generated over the entire ultrasonic irradiation region. it can.

1 is a functional block diagram illustrating a configuration of an ultrasound diagnostic apparatus 100 according to Embodiment 1. FIG. 3 is a schematic diagram illustrating a propagation path of an ultrasonic transmission wave by a transmission beam former unit 103 in the ultrasonic diagnostic apparatus 100. FIG. 3 is a functional block diagram showing a configuration of a reception beamformer unit 104 in the ultrasonic diagnostic apparatus 100. FIG. FIG. 6 is a schematic diagram illustrating a relationship between a reception aperture Rx and a transmission aperture Tx set by the reception beamformer unit 104. It is a schematic diagram for explaining a propagation path of an ultrasonic wave radiated from a transmission aperture Tx, reflected at an observation point Pij at an arbitrary position in the ultrasonic wave irradiation area Ax, and reaching a transducer in the reception aperture Rx. 5 is a flowchart showing a beamforming process operation of the reception beamformer unit 104. 5 is a flowchart showing an acoustic line signal generation operation for an observation point Pij in the reception beamformer unit 104. 6 is a schematic diagram for explaining an acoustic line signal generation operation for an observation point Pij in the reception beamformer unit 104. FIG. 6 is a functional block diagram showing a configuration of a reception beamformer unit 104A of an ultrasonic diagnostic apparatus 100A according to Embodiment 2. FIG. It is a schematic diagram which shows the relationship between the receiving aperture Rx set by 104 A of receiving beam former parts, and the transmission aperture Tx. It is a flowchart which shows the beam forming process operation | movement of 104 A of reception beam former parts. It is a schematic diagram for demonstrating the acoustic line signal production | generation operation | movement about the observation point Pij in 104 A of reception beam former parts. FIG. 10 is a functional block diagram of a main part of a reception beamformer unit 104B of an ultrasonic diagnostic apparatus 100B according to Embodiment 3. FIG. 10 is a functional block diagram of a main part of a reception beamformer unit 104C of an ultrasonic diagnostic apparatus 100C according to Modification 1. FIG. 10 is a schematic diagram for explaining an input signal of a Tx / Rx weight signal calculation unit 701A in a reception beamformer unit of an ultrasonic diagnostic apparatus according to Modification 2. It is a schematic diagram for demonstrating operation | movement of the reception beam former part 202 in the conventional ultrasonic signal processing apparatus.

≪Background to the form for carrying out the invention≫
The inventor has conducted various studies on an ultrasonic diagnostic apparatus in order to improve resolution and signal S / N ratio in an ultrasonic image.
In the conventional ultrasonic diagnostic apparatus described in Non-Patent Document 1, in general, when ultrasonic transmission to a subject is performed by a plurality of transducers, the ultrasonic beam is focused at a certain depth of the subject. Transmission beam forming is performed so as to tie. At this time, when the observation point P is in the vicinity of the transmission focus point, the ultrasonic beam is narrowed in the vicinity of the transmission focus point, so that the resolution of the ultrasonic beam is increased and the spatial energy density is high. The signal S / N ratio of reflected ultrasonic waves (S is an echo signal radiated from the target observation point P, and N is a signal from other areas). As a result, it is possible to obtain an ultrasonic image with high resolution and signal S / N ratio of the obtained acoustic line signal and high image quality. On the other hand, even when the observation point P is located on the central axis of the transmission ultrasonic beam, if the observation point P is located away from the vicinity of the transmission focus point, the resolution of the obtained acoustic line signal and the signal S / N ratio are obtained. It is difficult to obtain a low-quality and high-quality ultrasonic image.

  Further, in the conventional ultrasonic diagnostic apparatus, in order to set the observation point P on the central axis of the transmission ultrasonic beam, the observation point P from the observation point P located on the central axis of the transmission ultrasonic beam in the ultrasonic irradiation range. Reception beam forming is performed based only on the reflected ultrasonic waves. Therefore, only one acoustic line signal on the central axis of the transmission ultrasonic beam can be generated from one ultrasonic transmission event, and there is a problem that the use efficiency of ultrasonic waves is poor.

  On the other hand, a receiving beamforming method has been devised that obtains a high-resolution and high-quality image even in a region other than the vicinity of the transmission focus point by a synthetic aperture method (for example, Non-Patent Document 2). ). According to this method, by performing delay control that takes into account both the propagation path of the ultrasonic transmission wave and the arrival time of the reflected wave to the transducer through the propagation path, the ultrasonic wave located outside the vicinity of the transmission focus point Reception beam forming that reflects reflected ultrasonic waves from the irradiation region can be performed. As a result, an acoustic line signal can be generated for the entire ultrasonic irradiation region from a single ultrasonic transmission event. Further, in the synthetic aperture method, the transmission focus is virtually adjusted based on a plurality of reception signals for the same observation point P obtained from a plurality of transmission events, thereby comparing with the reception beamforming method described in Non-Patent Document 1. Thus, an ultrasonic image having a high resolution and a high signal S / N ratio can be obtained.

  However, even in the receive beamforming method using the synthetic aperture method, the examination site of the subject to be examined, the type of the disease, the characteristics of the examination site, the degree of the disease, etc. ) May not provide sufficient image quality. In that case, it is necessary to select and adjust the reception beamforming method or change the reception beamforming method in accordance with the characteristics of the examination region, which causes a reduction in examination efficiency.

  The inventor diligently studied the factors in the case where sufficient image quality cannot be obtained due to the characteristics of the examination site. As a result, it was found that the signal S / N ratio is not necessarily proportional to the spatial resolution, although the spatial resolution of the entire image can be improved by setting the reception aperture wider. And knowledge that it is necessary to ensure uniform spatial resolution in a wide observation area while maintaining high local spatial resolution to obtain sufficient image quality regardless of the characteristics of the examination site It came to. Therefore, the inventor has developed a technology that achieves both high local spatial resolution and uniform spatial resolution in a wide observation area, or high local spatial resolution and uniform spatial resolution in a wide observation area. As a result, the inventors have intensively studied a technique for achieving both a reception apodization and an ultrasonic image processing method according to an embodiment of the present invention and an ultrasonic diagnostic apparatus using the ultrasonic image processing method.

Hereinafter, an ultrasonic image processing method according to an embodiment and an ultrasonic diagnostic apparatus using the same will be described in detail with reference to the drawings.
<< Outline of Embodiment for Implementing the Present Invention >>
The ultrasonic signal processing apparatus according to the present embodiment is an ultrasonic signal processing apparatus that transmits an ultrasonic wave from an ultrasonic probe to a subject and generates an acoustic line signal from a received signal based on the obtained reflected ultrasonic wave. An ultrasonic signal processing circuit, and the ultrasonic signal processing circuit transmits ultrasonic waves from a first transducer array corresponding to all or a part of the plurality of transducers in the ultrasonic probe; A receiving unit that generates a reception signal sequence for each transducer based on reflected ultrasound from the subject obtained by the plurality of transducers, and a center of the column corresponds to a part of the plurality of transducers. A transmission aperture setting unit that selects a second transducer array that matches the column center of one transducer array, and a plurality of observation points that are located within a range in which a transmitted ultrasound wave reaches the subject. Each ultrasound in the subject A transmission time calculation unit for calculating a transmission time until the point is reached, and reception for calculating a reception time for a reflected wave from each observation point to reach each reception transducer included in the second transducer array From the sum of the time calculation unit and the transmission time and the reception time, a total propagation time until the transmitted ultrasonic wave is reflected at each observation point and reaches each reception transducer is calculated, and the total propagation is calculated. A delay amount calculation unit that calculates a delay amount for each reception transducer based on time; a delay processing unit that identifies a reception signal value corresponding to the delay amount from the reception signal sequence for each reception transducer; And an addition unit that generates an acoustic line signal for each observation point based on the reception signal value identified corresponding to each reception transducer. Moreover, the structure which adds the received signal value identified corresponding to each said receiving vibrator | oscillator may be sufficient as the said addition part.

In another aspect, the method further includes a weight calculation unit that calculates a weight sequence for each of the receiving transducers so that the weight for the transducer located at the column center of the second transducer sequence is maximized. The unit may be configured to multiply the received signal value identified corresponding to each receiving transducer by a weight for each receiving transducer and add.
In another aspect, the reception aperture setting unit is a first reception aperture setting unit, the reception time calculation unit is a first reception time calculation unit, the delay amount calculation unit is a first delay amount calculation unit, When the delay processing unit is a first delay processing unit, the adding unit is a first adding unit, the receiving transducer is a first receiving transducer, and the acoustic line signal is a first acoustic line signal, A second receiving aperture setting unit that selects a third transducer array so that the center of the column matches the transducer that is spatially closest to the observation point; and a reflected wave from the observation point From the sum of the second reception time calculation unit that calculates the reception time to reach each of the second reception transducers included in the transducer array, and the transmission time and the reception time, the transmitted ultrasonic waves are The total propagation time from the observation point to the arrival at each second receiving transducer is calculated, and the total propagation time is calculated. A second delay amount calculation unit that calculates a delay amount for each of the second reception transducers based on time, and a reception signal corresponding to the delay amount from the reception signal sequence for each of the second reception transducers A second delay processing unit for identifying a value, and a second addition unit for generating a second acoustic line signal for the observation point based on the received signal value identified corresponding to each of the second receiving transducers The structure provided with may be sufficient.

According to another aspect, a weight calculation unit is further provided for calculating a weight number sequence for each of the second receiving transducers so that the weight for the transducer located at the column center of the third transducer sequence is maximized. The second adder may be configured to add the received signal value identified corresponding to each second receiving transducer by multiplying the weight for each second receiving transducer by the weight. .
In another aspect, a Tx / Rx selection signal calculating unit that selects either the first acoustic line signal or the second acoustic line signal, and the first acoustic line signal based on a selection result. Or the structure provided with the selection output part which outputs either of the said 2nd acoustic line signal may be sufficient. The second addition unit may be configured to add reception signal values identified corresponding to the second reception transducers.

In another aspect, the Tx / Rx selection signal calculation unit calculates either the first acoustic line signal or the second acoustic line signal based on an operation input from an operator or a preset condition. The structure to select may be sufficient.
According to another aspect, the Tx / Rx selection signal calculation unit is configured to select either the first acoustic line signal or the second acoustic line signal based on a feature amount of a received signal. Also good.

In another aspect, the Tx / Rx selection signal calculation unit determines the presence or absence of a puncture needle based on the received signal, and selects the first acoustic line signal when determining that the puncture needle is present. It may be configured to.
In another aspect, the Tx / Rx selection signal calculation unit determines the presence or absence of a puncture needle based on whether or not a mirror surface structure is detected based on a received signal, and the mirror surface structure is detected and the puncture is detected. When it is determined that there is a needle, the first acoustic line signal may be selected.

In another aspect, the Tx / Rx selection signal calculation unit is configured to use the first acoustic line signal or the second acoustic line based on the first acoustic line signal and / or the second acoustic line signal. It may be configured to select any one of the line signals.
In another aspect, a Tx / Rx weight calculating unit that calculates a weight for each of the first acoustic line signal and the second acoustic line signal, and the first acoustic line using the weight. A configuration including a mixed output unit that outputs a result obtained by multiplying the signal and the second acoustic line signal by a weight for each of the signals and the second acoustic line signal may be used.

In another aspect, the Tx / Rx weight calculation unit is configured to input the first acoustic line signal and the second acoustic line to the observation point based on an operation input from an operator or a preset condition. It may be configured to calculate the weight for each of the signals.
In another aspect, the Tx / Rx weight calculation unit calculates a weight for each of the first acoustic line signal and the second acoustic line signal for the observation point based on a feature amount of the received signal. It may be a configuration.

In another aspect, the Tx / Rx weight calculation unit is configured to use the first acoustic line signal for the observation point and the first acoustic line signal for the observation point based on the first acoustic line signal and the second acoustic line signal for the observation point. The configuration may be such that a weight for each of the second acoustic line signals is calculated.
In another aspect, the feature amount includes a reception signal based on a reflected ultrasonic wave from the observation point identified corresponding to the first reception transducer having the smallest delay amount, and the smallest delay amount. The configuration may be calculated based on the received signal value identified corresponding to the second receiving transducer.

  In another aspect, when the transducer included in the first transducer array is a part of a plurality of transducers in the ultrasonic probe, the transmission unit further includes the plurality of transducers. The ultrasonic transducer is sequentially transmitted from a transducer array different from the first transducer array by using a different transducer array for each ultrasonic transmission, and the adding unit is based on a different ultrasonic transmission. A configuration may be used in which a plurality of acoustic line signals for the generated observation point at the same position are combined to generate an acoustic line signal for the observation point.

In another aspect, the transmission unit is configured to perform ultrasonic transmission from all of the plurality of transducers in the ultrasonic probe by sequentially performing ultrasonic transmission with different transducer rows to be used. Also good.
In another aspect, an ultrasonic diagnostic apparatus configured to be connectable with the ultrasonic probe may be used.

<< Embodiment 1 >>
<Overall configuration>
Hereinafter, an ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 1 is a functional block diagram of an ultrasonic diagnostic system 1000 according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic system 1000 transmits and receives ultrasonic waves to a probe 101 having a plurality of transducers 101a that transmit ultrasonic waves toward a subject and receive reflected waves. It has an ultrasonic diagnostic apparatus 100 that generates an ultrasonic image based on an output signal from the probe 101, and a display unit 106 that displays the ultrasonic image on a screen. The probe 101 and the display unit 106 are each configured to be connectable to the ultrasonic diagnostic apparatus 100. FIG. 1 shows a state in which a probe 101 and a display unit 106 are connected to the ultrasonic diagnostic apparatus 100. The probe 101 and the display unit 106 may be inside the ultrasonic diagnostic apparatus 100.

<Configuration of ultrasonic diagnostic apparatus 100>
The ultrasonic diagnostic apparatus 100 selects a transducer to be used for transmission or reception from a plurality of transducers 101a of the probe 101, and secures input / output for the selected transducer. Obtained by a plurality of transducers 101a based on a transmission beamformer unit 103 that controls the timing of applying a high voltage to each transducer 101a of the probe 101 and a reflected wave of ultrasonic waves received by the probe 101. A reception beam former 104 that amplifies the electrical signal, performs A / D conversion, and performs reception beam forming to generate an acoustic line signal. In addition, an ultrasonic image generation unit 105 that generates an ultrasonic image based on an output signal from the reception beamformer unit 104, an acoustic line signal output from the reception beamformer unit 104, and an ultrasonic wave output from the ultrasonic image generation unit 105 A data storage unit 107 that stores an image and a control unit 108 that controls each component are provided.

Among these, the multiplexer unit 102, the transmission beamformer unit 103, the reception beamformer unit 104, and the ultrasonic image generation unit 105 constitute an ultrasonic signal processing circuit 151, and the ultrasonic signal processing circuit 151 performs ultrasonic signal processing. The apparatus 150 is configured.
Each element constituting the ultrasonic diagnostic apparatus 100, for example, the multiplexer unit 102, the transmission beamformer unit 103, the reception beamformer unit 104, the ultrasonic image generation unit 105, and the control unit 108, for example, is an FPGA (Field Programmable Gate). Array) and an ASIC (Application Specific Integrated Circuit). Or the structure implement | achieved by programmable devices and software, such as CPU (Central Processing Unit) and a processor, may be sufficient. These components can be a single circuit component or an assembly of a plurality of circuit components. In addition, a plurality of components can be combined into one circuit component, or a plurality of circuit components can be assembled.

The data storage unit 107 is a computer-readable recording medium. For example, a flexible disk, a hard disk, an MO, a DVD, a DVD-RAM, a semiconductor memory, or the like can be used. The data storage unit 107 may be a storage device connected to the ultrasonic diagnostic apparatus 100 from the outside.
The ultrasonic diagnostic apparatus 100 according to the present embodiment is not limited to the ultrasonic diagnostic apparatus having the configuration shown in FIG. For example, there is a configuration in which the multiplexer unit 102 is unnecessary, and a configuration in which the probe 101 includes the transmission beamformer unit 103, the reception beamformer unit 104, or a part thereof may be employed.

<Configuration of Main Part of Ultrasonic Diagnostic Apparatus 100>
The ultrasonic diagnostic apparatus 100 according to the present embodiment is obtained from a transmission beam former 103 that performs ultrasonic transmission from each transducer 101 a of the probe 101 and reception of an ultrasonic reflected wave (echo signal) at the probe 101. The reception beamformer unit 104 generates an acoustic line signal for generating an ultrasonic image by calculating an electrical signal. Therefore, in this specification, the configuration and functions of the transmission beamformer unit 103 and the reception beamformer unit 104 will be mainly described. The configurations other than the transmission beamformer unit 103 and the reception beamformer unit 104 can be the same as those used in a known ultrasonic diagnostic apparatus. It is possible to replace and use the beamformer unit according to the embodiment.

Hereinafter, configurations of the transmission beamformer unit 103 and the reception beamformer unit 104 will be described.
1. Transmit beam former 103
The transmission beamformer unit 103 is connected to the probe 101 via the multiplexer unit 102, and in order to transmit ultrasonic waves from the probe 101, the transducer array (first array) corresponding to all or a part of the plurality of transducers 101a in the probe 101 is transmitted. The timing of applying a high voltage to each transducer included in the transmission aperture Tx comprising one transducer array) is controlled. The transmission beamformer unit 103 includes a transmission unit 1031.

  Based on the transmission control signal from the control unit 108, the transmission unit 1031 is a pulsed transmission signal for transmitting an ultrasonic beam to each transducer included in the transmission aperture Tx among the plurality of transducers 101 a in the probe 101. The transmission process for supplying is performed. Specifically, the transmission unit 1031 includes, for example, a clock generation circuit, a pulse generation circuit, and a delay circuit. The clock generation circuit is a circuit that generates a clock signal that determines the transmission timing of the ultrasonic beam. The pulse generation circuit is a circuit for generating a pulse signal for driving each vibrator. The delay circuit is a circuit for setting the ultrasonic beam transmission timing by setting a delay time for each transducer and delaying the transmission of the ultrasonic beam by the delay time.

  The transmission unit 1031 repeats ultrasonic transmission while gradually moving the transmission aperture Tx in the column direction for each ultrasonic transmission, and performs ultrasonic transmission from all the transducers 101 a in the probe 101. Information indicating the position of the transducer included in the transmission aperture Tx is output to the data storage unit 107 via the control unit 108. For example, when the total number of transducers 101a existing in the probe 101 is 192, for example, 20 to 100 may be selected as the number of transducer arrays constituting the transmission aperture Tx. Also good. Hereinafter, ultrasonic transmission performed from the same transmission opening Tx by the transmission unit 1031 is referred to as a transmission event.

FIG. 2 is a schematic diagram illustrating a propagation path of an ultrasonic transmission wave by the transmission beam former 103 in the ultrasonic diagnostic apparatus 100. In a certain transmission event, a row of transducers 101a arranged in an array contributing to ultrasonic transmission (first transducer row) is illustrated as a transmission aperture Tx. The column length of the transmission aperture Tx is referred to as the transmission aperture length.
In the transmission beamformer unit 103, the ultrasonic wave transmitted from the transducer array in the transmission aperture Tx is controlled by controlling the transmission timing of each transducer so that the transducer is positioned at the center of the transmission aperture Tx. The transmission wave is in a state where the transmission focus point F (Focal point) is met at one point where the wavefront exists at a certain depth (Focal depth) of the subject. The depth of the transmission focus point F can be arbitrarily set. The wavefront focused at the transmission focus point F is diffused again, and the ultrasonic wave is transmitted through an hourglass-shaped space defined by two intersecting straight lines with the transmission aperture Tx as the bottom and the transmission focus point F as a node. Is propagated. That is, the ultrasonic wave radiated from the transmission aperture Tx is gradually reduced in width in the space (horizontal axis direction in the figure), minimized at the transmission focus point F, and deeper than that (see FIG. As it progresses to the upper part, it diffuses and propagates again while increasing its width. This hourglass-shaped region (the region indicated by hatching) is referred to as an ultrasonic irradiation region Ax.

2. Configuration of Reception Beamformer Unit 104 The reception beamformer unit 104 generates an acoustic line signal from the electrical signals obtained by the plurality of transducers 101a based on the reflected ultrasonic wave received by the probe 101. FIG. 3 is a functional block diagram showing the configuration of the reception beamformer unit 104. As shown in FIG. 3, the reception beamformer unit 104 includes a reception unit 1041, a reception aperture setting unit 1042, a transmission time calculation unit 1043, a reception time calculation unit 1044, a delay amount calculation unit 1045, a delay processing unit 1046, and a weight calculation unit. 1047 and an adder 1048.

Hereinafter, the configuration of each unit constituting the reception beamformer unit 104 will be described. (1) Reception unit 1041
The receiving unit 1041 is connected to the probe 101 via the multiplexer unit 102, amplifies the electrical signal obtained from the reception of the ultrasonic reflected wave at the probe 101 for each transmission event, and then AD-converts the received signal (RF signal). This is a circuit to be generated. Received signals are generated in time series in the order of transmission events, output to the data storage unit 107, and stored in the data storage unit 107.

Here, the received signal (RF signal) is a digital signal obtained by A / D-converting an electrical signal converted from the reflected ultrasonic wave received by each transducer, and the ultrasonic wave received by each transducer. The signal sequence connected in the transmission direction (depth direction of the subject) is formed.
In the transmission event, as described above, the transmission unit 1031 transmits the ultrasonic beam to each transducer included in the transmission aperture Tx among the plurality of transducers 101a in the probe 101. On the other hand, the receiving unit 1041 receives a received signal for each transducer based on the reflected ultrasonic wave obtained by each transducer corresponding to some or all of the plurality of transducers 101a existing in the probe 101 for each transmission event. Generate a column. Here, it is preferable that the number of transducers that receive the reflected ultrasonic waves is larger than the number of transducers included in the transmission aperture Tx. Further, the number of the transducers may be the total number of transducers 101a existing in the probe 101.

The transmission unit 1031 repeats ultrasonic transmission while gradually moving the transmission aperture Tx in the column direction for each transmission event, and performs ultrasonic transmission from the entire plurality of transducers 101 a in the probe 101. The reception unit 1041 generates a sequence of reception signals for each transducer for each transmission event, and the generated reception signals are stored in the data storage unit 107.
(2) Reception aperture setting unit 1042
Based on the control signal from the control unit 108, the reception aperture setting unit 1042 hits a part of a plurality of transducers existing in the probe 101, and a transducer whose column center matches the column center of the transducer array included in the transmission aperture Tx This is a circuit that sets a reception aperture Rx by selecting a column (second transducer column) as a reception transducer.

  FIG. 4 is a schematic diagram showing the relationship between the reception aperture Rx and the transmission aperture Tx set by the reception beamformer unit 104. As shown in FIG. 4, in the present embodiment, the position of the central axis Rxo of the reception aperture Rx is the same as the position of the central axis Txo of the transmission aperture Tx, and the reception aperture Rx is centered on the transmission focus point F. Symmetric opening. Therefore, the position of the reception aperture Rx also moves in synchronization with the change in the position of the transmission aperture Tx that moves in the column direction for each transmission event.

Further, in order to receive the reflected wave from the entire ultrasonic irradiation region, the number of transducers included in the reception aperture Rx may be set to be equal to or greater than the number of transducers included in the transmission aperture Tx in the corresponding transmission event. preferable. The number of transducer arrays that form the reception aperture Rx may be, for example, 32, 64, 96, 128, 192, or the like.
The reception aperture Rx is set as many times as the transmission event corresponding to the transmission event. The setting of the reception aperture Rx may be performed gradually in synchronization with the transmission event, or after all the transmission events are finished, the setting of the reception aperture Rx corresponding to each transmission event is the transmission event. The number of times may be collectively performed.

Information indicating the position of the selected reception aperture Rx is output to the data storage unit 107 via the control unit 108.
The data storage unit 107 to which the information indicating the position of the reception aperture Rx is output includes the transmission time calculation unit 1043, the reception time calculation unit 1044, the information indicating the position of the reception aperture Rx and the reception signal corresponding to the reception transducer. The data is output to the delay processing unit 1046.

(3) Transmission time calculation unit 1043
The transmission time calculation unit 1043 is a circuit that calculates the transmission time for the transmitted ultrasonic waves to reach the observation point P in the subject. Corresponding to the transmission event, an arbitrary observation point Pij existing in the ultrasonic irradiation region Ax is transmitted based on the information obtained from the data storage unit 107 and indicating the position of the transducer included in the transmission aperture Tx. A transmission time for the ultrasonic wave to reach the observation point Pij in the subject is calculated.

  FIG. 5 illustrates the propagation path of the ultrasonic wave radiated from the transmission aperture Tx, reflected at the observation point Pij at an arbitrary position in the ultrasonic irradiation region Ax, and reaching the reception transducer Rk positioned in the reception aperture Rx. It is a schematic diagram for doing. The transmitted wave radiated from the transmission aperture Tx gathers at the transmission focus point F through the path 401, reaches the observation point Pij while spreading again, and if the acoustic impedance changes at the observation point Pij. A reflected wave is generated, and the reflected wave returns to the reception transducer Rk in the reception opening Rx of the probe 101. Since the transmission focus point F is defined as a design value of the transmission beamformer unit 103, the length of the path 402 from the transmission focus point F to an arbitrary observation point Pij can be calculated geometrically.

The transmission time calculation unit 1043 sets the transmission time for the transmitted ultrasonic waves to reach the observation points Pij in the subject for all the observation points Pij existing in the ultrasonic irradiation region Ax for one transmission event. Calculate and output to the delay amount calculation unit 1045.
(4) Reception time calculation unit 1044
The reception time calculation unit 1044 is a circuit that calculates the reception time when the reflected wave from the observation point P reaches each of the reception transducers Rk included in the reception opening Rx. Corresponding to the transmission event, based on the information indicating the position of the receiving transducer Rk acquired from the data storage unit 107, the transmitted ultrasonic wave is detected at any observation point Pij existing in the ultrasonic irradiation region Ax. The reception time that is reflected at the central observation point Pij and reaches each reception transducer Rk in the reception aperture Rx is calculated.

  As described above, the transmitted wave that has reached the observation point Pij generates a reflected wave if the acoustic impedance changes at the observation point Pij, and the reflected wave returns to each reception transducer Rk in the reception aperture Rx of the probe 101. To go. Since the position information of each reception transducer Rk within the reception aperture Rx is acquired from the data storage unit 107, the length of the path 403 from any observation point Pij to each reception transducer Rk should be calculated geometrically. Can do.

For one transmission event, the reception time calculation unit 1044 reflects the transmitted ultrasonic waves at the observation points Pij for all the observation points Pij existing in the ultrasonic irradiation region Ax, and then receives them at each reception transducer Rk. The arrival time for arrival is calculated and output to the delay amount calculation unit 1045.
(5) Delay amount calculation unit 1045
The delay amount calculation unit 1045 calculates the total propagation time to each reception transducer Rk in the reception aperture Rx from the transmission time and the reception time, and based on the total propagation time, the received signal of each reception transducer Rk This is a circuit for calculating a delay amount applied to a column. The delay amount calculation unit 1045 obtains the transmission time when the ultrasonic wave transmitted from the transmission time calculation unit 1043 reaches the observation point Pij and the reception time reflected at the observation point Pij and reaching each receiving transducer Rk. Then, the total propagation time until the transmitted ultrasonic wave reaches each reception transducer Rk is calculated, and the delay amount for each reception transducer Rk is calculated based on the difference in the total propagation time for each reception transducer Rk. The delay amount calculation unit 1045 calculates the delay amount to be applied to the train of received signals for each reception transducer Rk for all observation points Pij existing in the ultrasonic irradiation region Ax, and outputs the delay amount to the delay processing unit 1046.

(6) Delay processing unit 1046
The delay processing unit 1046 receives each reception vibration based on the reflected ultrasonic wave from the observation point Pij, from the sequence of reception signals for the reception transducer Rk in the reception aperture Rx, and corresponding to the delay amount for each reception transducer Rk. It is a circuit that identifies the received signal corresponding to the child Rk. In response to the transmission event, the delay processing unit 1046 receives information indicating the position of the reception transducer Rk from the data storage unit 107 and a reception signal corresponding to the reception transducer Rk from the delay amount calculation unit 1045 to each reception transducer. The delay amount applied to the received signal sequence for Rk is acquired as an input. Then, the reception signal corresponding to the time obtained by subtracting the delay amount for each reception transducer Rk from the sequence of reception signals corresponding to each reception transducer Rk is identified as the reception signal based on the reflected wave from the observation point Pij and added. Output to the unit 1048.

(7) Weight calculation unit 1047
The weight calculation unit 1047 is a circuit that calculates a weight sequence (reception apodization) for each reception transducer Rk so that the weight for the transducer located at the center in the column direction of the reception aperture Rx is maximized.
As shown in FIG. 4, the weight sequence is a sequence of weight coefficients applied to the reception signal corresponding to each transducer in the reception aperture Rx. The weight sequence has a symmetric distribution around the transmission focus point F. As the distribution shape of the weight sequence, a Hamming window, Hanning window, rectangular window, or the like can be used, and the distribution shape is not particularly limited. The weight sequence is set so that the weight for the transducer located at the center in the column direction of the reception aperture Rx is maximized, and the central axis of the distribution of the weights coincides with the reception aperture central axis Rxo. The weight calculation unit 1047 receives the information indicating the position of the reception transducer Rk output from the data storage unit 107 as an input, calculates a weight sequence for each reception transducer Rk, and outputs it to the addition unit 1048.

(8) Adder 1048
The adder 1048 receives the received signals identified corresponding to the respective receiving transducers Rk output from the delay processor 1046, adds them, and outputs the phasing-added acoustic line signal for the observation point Pij. This is a circuit to be generated. Alternatively, the weight signal for each reception transducer Rk output from the weight calculation unit 1047 is used as an input, and the received signal identified corresponding to each reception transducer Rk is multiplied by the weight for each reception transducer Rk. It is good also as a structure which adds and produces | generates the acoustic line signal with respect to the observation point Pij. Here, the “acoustic ray signal” refers to a reception signal for the observation point Pij after the phasing addition process. In the delay processing 1046, the phase of the reception signal detected by each reception transducer Rk located in the reception aperture Rx is adjusted and the addition unit 1048 performs addition processing, whereby each reception is performed based on the reflected wave from the observation point Pij. It is possible to extract the reception signal from the observation point Pij by superimposing reception signals received by the transducer Rk and increasing the signal S / N ratio.

  An acoustic line signal can be generated for all the observation points Pij existing in the ultrasonic irradiation area Ax from one transmission event and the processing associated therewith. Then, for each transmission event, ultrasonic transmission is repeated while gradually moving the transmission aperture Tx in the column direction, and ultrasonic transmission is performed from all the transducers 101a in the probe 101, thereby generating an acoustic line signal of one frame. A “frame” refers to a unit of a single signal necessary for constructing one ultrasonic image. In addition, the acoustic line signals for all the observation points Pij existing in the ultrasonic irradiation region Ax generated from one transmission event are referred to as sub-frame acoustic line signals.

The adder 1048 generates sub-frame acoustic line signals for all observation points Pij existing in the ultrasonic irradiation region Ax for each transmission event. The generated subframe acoustic line signal is output and stored in the data storage unit 107.
<About operation>
The operation of the ultrasonic diagnostic apparatus 100 having the above configuration will be described. FIG. 6 is a flowchart showing the beamforming processing operation of the reception beamformer unit 104 in the ultrasonic diagnostic apparatus 100.

First, in step S101, the transmission unit 1031 transmits a transmission signal (transmission event) for transmitting an ultrasonic beam to each transducer included in the transmission aperture Tx in the plurality of transducers 101a in the probe 101. I do.
Next, in step S <b> 102, the reception unit 1041 generates a reception signal based on the electrical signal obtained from reception of the ultrasonic reflected wave by the probe 101, outputs the reception signal to the data storage unit 107, and outputs the reception signal to the data storage unit 107. save. It is determined whether or not ultrasonic transmission has been completed from all transducers 101a in the probe 101 (step S103). If not completed, the process returns to step S101 to perform a transmission event while gradually moving the transmission opening Tx in the column direction. If completed, the process proceeds to step S104.

Next, in step S104, the reception aperture setting unit 1042 selects, as a reception transducer Rk, a transducer array whose column center matches the column center of the transducer array included in the transmission aperture Tx corresponding to the transmission event. A reception aperture Rx is set.
Next, the coordinates ij indicating the position of the observation point Pij in the ultrasonic irradiation area Ax obtained from the transmission opening Tx and the reception opening Rx are initialized to the minimum value in the ultrasonic irradiation area Ax (steps S105 and S106) and observed. An acoustic line signal is generated for the point Pij (step S107).

Next, an operation of generating an acoustic line signal for the observation point Pij in step S107 will be described. FIG. 7 is a flowchart showing an acoustic line signal generation operation for the observation point Pij in the reception beamformer unit 104. FIG. 8 is a schematic diagram for explaining an acoustic line signal generation operation for the observation point Pij in the reception beamformer unit 104.
First, in step S1071, the transmission time calculation unit 1043 calculates the transmission time at which the transmitted ultrasonic wave reaches the observation point Pij in the subject for any observation point Pij existing in the ultrasonic irradiation region Ax. . The transmission time is calculated by dividing the length of the path (401 + 402) from the receiving transducer within the geometrically determined receiving aperture Rx via the transmission focus point F to the observation point Pij by the ultrasonic sound velocity cs. it can.

  Next, the coordinate k indicating the position of the reception transducer Rk in the reception aperture Rx is initialized to the minimum value in the reception aperture Rx (step S1072), and the transmitted ultrasonic wave is reflected by the observation point Pij in the subject and received. The reception time for reaching the receiving transducer Rk in the opening Rx is calculated (step S1073). The reception time can be calculated by dividing the length of the path 403 from the geometrically determined observation point Pij to the reception transducer Rk by the ultrasonic velocity cs. Further, from the total of the transmission time and the reception time, the total propagation time until the ultrasonic wave transmitted from the transmission aperture Tx is reflected at the observation point Pij and reaches the reception transducer Rk is calculated (step S1074), and the reception aperture is calculated. Based on the difference in the total propagation time for each receiving transducer Rk in Rx, a delay amount for each receiving transducer Rk is calculated (step S1075).

  It is determined whether or not the calculation of the delay amount has been completed for all the reception transducers Rk existing in the reception aperture Rx (step S1076). If not completed, the coordinate k is incremented (step S1077). Further, a delay amount is calculated for the receiving transducer Rk (step S1073), and if completed, the process proceeds to step S1078. At this stage, the delay amount of the reflected wave arrival from the observation point Pij is calculated for all the reception transducers Rk existing in the reception opening Rx.

In step S1078, the delay processing unit 1046 obtains a reception signal corresponding to the time obtained by subtracting the delay amount for each reception transducer Rk from the observation point Pij from the sequence of reception signals corresponding to the reception transducer Rk in the reception aperture Rx. The received signal is identified based on the reflected wave.
Next, the weight calculation unit 1047 calculates a weight sequence for each reception transducer Rk so that the weight for the transducer located at the center of the reception aperture Rx in the column direction is maximized (step S1079). The adder 1048 multiplies the reception signal identified corresponding to each reception transducer Rk by the weight for each reception transducer Rk, and generates an acoustic line signal for the observation point Pij (step S1170). For the generated observation point Pij, the acoustic line signal is output and stored in the data storage unit 107 (step S1171).

  Next, returning to FIG. 6, the coordinate ij is incremented and the step S107 is repeated, so that the acoustic lines for all the observation points Pij (“·” in FIG. 8) located at the coordinates ij in the ultrasound irradiation region Ax. A signal is generated. It is determined whether or not the generation of the acoustic line signal has been completed for all the observation points Pij existing in the ultrasonic illumination region Ax (steps S108 and S110). If not, the coordinates ij are incremented (step S109). , S111), an acoustic line signal is generated for the observation point Pij (step S107), and if completed, the process proceeds to step S112. In this stage, sub-frame acoustic line signals for all observation points Pij existing in the ultrasound irradiation area Ax associated with one transmission event are generated and output to the data storage unit 107 and stored.

  Next, in step S112, the presence / absence of the acoustic line signal generated in step S107 and the acoustic line signal already generated by a different transmission event for the observation point P at the same position and stored in the data storage unit 107 Determine. If present, the adding unit 1048 synthesizes the acoustic line signal generated in step S <b> 107 and the acoustic line signal stored in the data storage unit 107. For all transmission events, it is determined whether or not the generation of the acoustic line signal of the subframe has been completed (step S113). If not completed, the process returns to step S104, and the transmission aperture Tx in the next transmission event is determined. A reception aperture Rx corresponding to is set (step S104).

<Effect>
In the ultrasonic diagnostic apparatus 100 according to the present embodiment described above, with the above-described configuration, the reception aperture setting unit 1042 corresponds to the column center of the transducer array whose column center is included in the transmission aperture Tx corresponding to the transmission event. A matching transducer array is selected as a reception transducer and a reception aperture Rx is set. Therefore, the position of the central axis Rxo of the reception aperture Rx is the same as the position of the central axis Txo of the transmission aperture Tx, and the reception aperture is synchronized with the position change of the transmission aperture Tx that moves in the column direction for each transmission event. The position of Rx also changes (moves). Alternatively, the reception beam former is further performed using reception apodization that is symmetrical in the column direction with the position of the central axis Txo of the transmission aperture Tx as the center. Therefore, phasing addition can be performed at different reception apertures (or reception apertures and reception apodization) for each transmission event, and although reception times are different over a plurality of transmission events, as a result, a wider reception aperture (or , Reception aperture and reception apodization) can be obtained, and the spatial resolution can be made uniform over a wide observation area.

  In the ultrasonic diagnostic apparatus 100, the ultrasonic wave transmitted from the transmission aperture Tx is reflected at the observation point Pij in the ultrasonic irradiation area Ax via the transmission focus point F and reaches the reception transducer Rk of the reception aperture Rx. By performing delay control based on the total propagation path by calculating the total propagation time until the time is reached, phasing addition focused on each point is performed for all observation points Pij located in the ultrasonic irradiation region Ax, and the point An acoustic line signal is generated for. As a result, an acoustic line signal can be generated from a single ultrasonic transmission event based on reflected ultrasonic waves from a range other than on the central axis of the transmitted ultrasonic beam in the ultrasonic irradiation range. The spatial resolution and the signal S / N ratio can be improved by improving the use efficiency of sound waves.

  Furthermore, the ultrasonic diagnostic apparatus 100 synthesizes by superimposing the acoustic line signal on the observation point P at the same position generated by different transmission events by the synthetic aperture method. As a result, even at the observation point P at a depth other than the transmission focus point F with respect to a plurality of transmission events, the effect of performing the virtual transmission focus is obtained, and the spatial resolution and the signal S / N ratio are further improved. be able to.

<< Embodiment 2 >>
In the ultrasonic diagnostic apparatus 100 according to Embodiment 1, the reception aperture setting unit 1042 is configured to select a reception aperture Rx transducer array whose column center matches the column center of the transmission aperture Tx transducer array. However, the configuration of the reception aperture Rx is such that the ultrasonic wave transmitted from the transmission aperture Tx is reflected at the observation point Pij in the ultrasonic illumination region Ax via the transmission focus point F and reaches the reception transducer Rk in the reception aperture Rx. It is only necessary to calculate the total propagation time up to and perform delay control based on the total propagation path so as to generate acoustic line signals for all observation points Pij located in the ultrasonic irradiation region Ax. The configuration of the reception aperture Rx can be changed as appropriate.

  In the second embodiment, the reception aperture setting unit 1042A in the reception beamformer unit 104A is configured to select the reception aperture Rx so that the column center matches the transducer that is spatially closest to the observation point P. The configuration other than the reception aperture setting unit 1042A is the same as each element shown in the first embodiment, and the description of the same part is omitted. The ultrasonic diagnostic apparatus 100A includes an ultrasonic signal processing circuit including the same multiplexer unit 102, transmission beamformer unit 103, and ultrasonic image generation unit 105 as in the first embodiment, in addition to the reception beamformer unit 104A. A sonic signal processing device is provided.

<Configuration>
Hereinafter, an ultrasonic diagnostic apparatus 100A according to Embodiment 2 will be described with reference to the drawings. FIG. 9 is a functional block diagram showing the configuration of the reception beamformer unit 104A of the ultrasonic diagnostic apparatus 100A. The ultrasonic diagnostic apparatus 100A is different from the ultrasonic diagnostic apparatus 100 in that a reception aperture setting unit 1042A is provided instead of the reception aperture setting unit 1042 in the ultrasonic diagnostic device 100. The configuration other than the reception aperture setting unit 1042A is the same as that of the ultrasonic diagnostic apparatus 100, and the description of the same part is omitted.

  As described above, the reception aperture setting unit 1042A selects the reception aperture Rx transducer array so that the column center matches the transducer that is spatially closest to the observation point P. FIG. 10 is a schematic diagram showing the relationship between the reception aperture Rx and the transmission aperture Tx set by the reception beamformer unit 104A. As shown in FIG. 10, in the second embodiment, the reception aperture Rx transducer array is selected so that the column center of the reception aperture Rx transducer array matches the transducer Xk spatially closest to the observation point Pij. Is done. Further, a weight sequence (reception apodization) for each reception transducer Rk in the reception aperture Rx is calculated so that the weight for the transducer Xk located at the center of the reception aperture Rx in the column direction is maximized. The weight sequence has a symmetric distribution around the transducer Xk. As the distribution shape of the weight sequence, a Hamming window, Hanning window, rectangular window, or the like can be used, and the distribution shape is not particularly limited.

  Therefore, the position of the reception aperture Rx is determined by the position of the observation point Pij and does not change based on the position of the transmission aperture Tx that varies for each transmission event. That is, even in different transmission events, in the process of generating the acoustic line signal for the observation point Pij at the same position, the phasing is performed based on the reception signals acquired by the reception transducers Rk in the same reception opening Rx. Addition is performed.

<About operation>
FIG. 11 is a flowchart showing the beamforming processing operation of the reception beamformer unit 104A. This flowchart is different in that the observation point synchronous beamforming process (steps S20 (S204 to S211)) is performed instead of the transmission synchronous beamforming process (steps S10 (S104 to S111)) in FIG. The processes other than step S20 are the same as those in FIG. 6, and the description of the same parts is omitted.

First, the coordinates ij indicating the position of the observation point Pij are initialized to the minimum value in the ultrasound irradiation area Ax obtained from the transmission aperture Tx in the first transmission event (steps S205 and S206), and the reception aperture setting unit 1042A is set in the column The receiving aperture Rx transducer array is selected so that the center coincides with the transducer Xk that is spatially closest to the observation point Pij (step S204).
Next, an acoustic line signal is generated for the observation point Pij (step S207).

  FIG. 12 is a schematic diagram for explaining an acoustic line signal generation operation for the observation point Pij in the reception beamformer unit 104A. The processing method in step S207 is the same as step S107 in FIG. 6 (steps S1071 to S1171 in FIG. 7). By incrementing the coordinate ij and repeating step S207, acoustic line signals are generated for all observation points Pij (“·” in FIG. 12) located at the coordinate ij in the ultrasonic irradiation region Ax. It is determined whether or not the generation of the acoustic line signal has been completed for all the observation points Pij existing in the ultrasonic illumination region Ax (steps S208 and S210). If not, the coordinates ij are incremented (step S209). S211), an acoustic line signal is generated for the observation point Pij (step S207), and if completed, the process proceeds to step S112. In this stage, sub-frame acoustic line signals for all observation points Pij existing in the ultrasound irradiation area Ax associated with one transmission event are generated and output to the data storage unit 107 and stored.

  Next, in step S112, there is an acoustic line signal that is already generated by a different transmission event for the observation point P at the same position and stored in the data storage unit 107, with respect to the acoustic point signal generated in step S207. If so, the adding unit 1048 synthesizes the acoustic line signal generated in step S207 and the acoustic line signal stored in the data storage unit 107.

  Next, for all transmission events, it is determined whether or not the generation of the acoustic line signal of the subframe is completed (step S113). If not completed, the process returns to step S205, and the position of the observation point Pij is set. The indicated coordinates ij are initialized to the minimum value in the ultrasound irradiation area Ax obtained from the transmission aperture Tx in the next transmission event (steps S205 and S206), the reception aperture Rx is set (step S204), and the process ends. If yes, the process ends.

<Effect>
As described above, in the ultrasonic diagnostic apparatus 100A according to the present embodiment, the reception aperture setting unit 1042A has the reception aperture Rx transducer so that the column center matches the transducer that is spatially closest to the observation point P. Based on the position of the observation point P without depending on the transmission event, a reception beamformer is performed using a reception aperture symmetric about the observation point P in the column direction. Alternatively, a reception beamformer is further performed using reception apodization that is symmetric about the observation point P in the column direction. For this reason, the position of the reception aperture (or reception aperture and reception apodization) is not synchronized with the transmission event that changes (moves) the transmission focus point F in the horizontal axis direction, and the same observation point P is obtained even in different transmission events. The phasing addition can be performed at the same reception aperture (or reception aperture and reception apodization). In addition, since a larger weight sequence can be applied to the reflected wave from the observation point P as the transducer has a smaller distance from the observation point P, the ultrasonic wave is attenuated depending on the propagation distance. The reflected wave can be received with the highest sensitivity to the observation point P. As a result, high spatial resolution and signal S / N ratio can be realized locally.

<< Embodiment 3 >>
In the ultrasonic diagnostic apparatus 100 according to the first embodiment, the reception aperture setting unit 1042 selects the reception aperture Rx transducer array whose column center matches the column center of the transmission aperture Tx transducer array ( A transmission synchronization type reception aperture (Tx)) is provided. In the ultrasound diagnostic apparatus 100A according to the second embodiment, the reception aperture setting unit 1042A selects the reception aperture Rx transducer array so that the column center matches the transducer that is spatially closest to the observation point P. The receiving beam former 104A (observation point synchronization type receiving aperture (Rx)) is provided.

However, in the configuration having the beam forming units 104 and 104A, both beam former units are used at the same time, and one of the beam formers is selected by a predetermined method or selection by an operator, or the beam former unit 104, The output of 104A may be mixed.
The ultrasonic diagnostic apparatus 100B according to the third embodiment replaces the reception beamformer unit 104 according to the first embodiment (or the reception beamformer unit 104A according to the second embodiment) with the reception beamformer units 104 and 104A. It is characterized in that it includes a selective output receiving beamformer unit 104B to be included. The configuration other than the selective output receiving beamformer unit 104B is the same as each element shown in the first embodiment, and the description of the same part is omitted. The ultrasonic diagnostic apparatus 100B includes an ultrasonic signal processing circuit including the same multiplexer unit 102, transmission beamformer unit 103, and ultrasonic image generation unit 105 as in the first embodiment, in addition to the reception beamformer unit 104B. A signal processing device is provided.

  FIG. 13 is a functional block diagram showing the configuration of the selective output reception beamformer unit 104B of the ultrasonic diagnostic apparatus 100B. As shown in FIG. 13, the selective output reception beamformer unit 104B calculates a selection signal for both outputs based on the outputs of the reception beamformer unit 104, the reception beamformer unit 104A, and both beamformer units. A selection signal calculation unit 701 and a selection output unit 704 that selects and outputs one of the outputs of the reception beamformer unit 104 and the reception beamformer unit 104A based on the selection signal.

  The Tx / Rx selection signal calculation unit 701 is an acoustic line signal output from the reception beamformer unit 104 (hereinafter referred to as a “first acoustic line signal”) and / or an acoustic line signal output from the reception beamformer unit 104A ( (Hereinafter referred to as “second acoustic line signal”) as an input, for example, a selection signal is calculated based on the value indicated by both signals, for example, the magnitude of the luminance value, and is output to the selection output unit 704. The selection signal is a signal indicating which of the first or second acoustic line signal is selected. The output from each beamformer unit input to the Tx / Rx selection signal calculation unit 701 is a phasing addition with respect to the observation point P in the hourglass type ultrasonic irradiation region Ax in the subject synthesized by the synthetic aperture method. Acoustic line signal. The selection output unit 704 receives the selection signal from the Tx / Rx selection signal calculation unit 701 and outputs the signal indicated by the selection signal among the first acoustic line signal and the second acoustic line signal to the ultrasonic image generation unit 105. Output to. Alternatively, the Tx / Rx selection signal calculation unit 701 may receive, as an input, a reception signal obtained by A / D converting an electrical signal based on an ultrasonic reflected wave acquired by a plurality of transducers of the probe 101. Here, the operation for switching the output signal of the selection output unit 704 is preferably performed for each frame. However, the configuration may be performed for each observation point or for each transmission event.

Another example of selection of the reception beamformer unit 104 and the reception beamformer unit 104A will be further described. They relate to the operation of the Tx / Rx selection signal calculation unit 701 and the selection output unit 704.
When a biopsy is performed by inserting a puncture needle into a living body to collect tissue or body fluid and diagnosing it, the puncture needle is inserted into the living body while checking the position of the puncture needle. At this time, the puncture needle may be inserted while attaching the puncture needle to an ultrasonic probe provided with an attachment or a guide and confirming the position of the puncture needle by an ultrasonic image. Then, when the puncture needle is inserted into the living body in this way, for example, the Tx / Rx selection signal calculation unit 701 determines the presence or absence of the puncture needle based on the first acoustic line signal or the second acoustic line signal. When it is determined that there is a puncture needle, the beam former unit 104 may be selected. In the determination of the presence or absence of the puncture needle, when the obtained acoustic line signal has a high-brightness linear reflection part, and a part of the linear reflection part is also observed from the body surface of the subject, It can be determined that there is a puncture needle.

  The reflected wave from the puncture needle is different from the echo image due to the scattering reflection seen in a general biological tissue, and the reflection of the ultrasonic wave is strongly influenced by the specular reflection. Therefore, since a strong reflected wave is generated in a direction determined based on the needle insertion angle to the living body and the positional relationship between the probe and the reflected wave from the puncture needle, the reflected wave from that specific direction is detected. It is essential to receive. On the other hand, the beamformer unit 104 according to the present embodiment uses a synthetic aperture technique, so that the reception aperture can be set wide, so that the configuration is suitable for receiving a reflected wave from a specific direction. It can be said. That is, it is preferable to use the beam former unit 104 for detection of the reflected wave from the puncture needle.

Note that the same configuration can be applied not only to the puncture needle but also when another mirror surface structure is inserted into the living body.
Further, the Tx / Rx selection signal calculation unit 701 may be configured to select either the first acoustic line signal or the second acoustic line signal based on an operation input from the operator or a preset condition. Here, the operation input from the operator may be an operation input for directly selecting either the first acoustic line signal or the second acoustic line signal. Alternatively, it may be an operation input for instructing another operation different from the operation of selecting either the first acoustic line signal or the second acoustic line signal. The operation input for instructing another operation may be an operation input for selecting a puncture needle mode for inserting a puncture needle, for example. The puncture needle mode is a mode in which the operator can grasp the positional relationship between the biological image and the puncture needle by drawing both the biological image and the puncture needle. In the puncture needle mode, for example, the needle tip may be highlighted. In the selection of the puncture needle mode, for example, the mode may be selected by an input unit such as a keyboard or a key connected to the ultrasonic diagnostic apparatus, or a predetermined ultrasonic probe registered in advance may be used. The mode may be selected based on the fact that the child is connected to the ultrasonic diagnostic apparatus.

When the Tx / Rx selection signal calculation unit 701 adopts the output of one of the beamformer units as the output of the selection output reception beamformer unit 104B in advance, the selection output unit 704 outputs a predetermined beamformer. The output of the unit is directly used as the output of the selective output reception beamformer unit 104B.
<Modification 1>
The ultrasonic diagnostic apparatus 100C according to the first modification of the third embodiment is characterized in that a mixed output reception beamformer unit 104C is provided instead of the selective output reception beamformer unit 104B according to the third embodiment. The configuration other than the mixed output reception beamformer unit 104C is the same as each element shown in the first embodiment, and the description of the same part is omitted. The ultrasonic diagnostic apparatus 100C includes an ultrasonic signal processing circuit including the same multiplexer unit 102, transmission beamformer unit 103, and ultrasonic image generation unit 105 as in the first embodiment, in addition to the reception beamformer unit 104C. A signal processing device is provided.

  FIG. 14 is a functional block diagram showing the configuration of the mixed output reception beamformer unit 104C of the ultrasonic diagnostic apparatus 100C. As shown in FIG. 13, the mixed output reception beamformer unit 104C calculates a weight signal for both outputs based on the outputs of the reception beamformer unit 104, the reception beamformer unit 104A, and both beamformer units. A weight signal calculation unit 701A and a mixed output unit 704A that outputs a result obtained by multiplying the outputs of the reception beamformer unit 104 and the reception beamformer unit 104A based on the weight signal by multiplying the respective weights.

  The Tx / Rx weight signal calculation unit 701A outputs the acoustic line signal (first acoustic line signal) output from the reception beamformer unit 104 and the acoustic line signal (second acoustic line signal) output from the reception beamformer unit 104A. As an input, for example, a weight signal indicating a mixing ratio of both signals is calculated according to a value indicated by both signals, for example, a ratio such as average luminance, and is output to the mixing output unit 704A. The mixed output unit 704A receives the weight signal from the Tx / Rx weight signal calculation unit 701A as input, and multiplies the weights for each of the first acoustic line signal and the second acoustic line signal to generate an ultrasonic image. Output to the unit 105. Further, the Tx / Rx weight signal calculation unit 701A may receive, as an input, a reception signal obtained by A / D converting an electrical signal based on the reflected wave of an ultrasonic wave acquired by a plurality of transducers of the probe 101. Here, it is preferable to perform the operation for changing the mixing ratio in the output signal of the mixing output unit 704A for each frame. However, the configuration may be performed for each observation point or for each transmission event.

  Further, the Tx / Rx weight signal calculation unit 701A may be configured to mix the first acoustic line signal and the second acoustic line signal based on an operation input from the operator or a preset condition. When the mixing ratio for the outputs of the two beamformers is determined in advance by the Tx / Rx weight signal calculation unit 701A4 (for example, 0.6: 0.4), the output of the mixed output reception beamformer unit 104C is The output of each beamformer multiplied by a predetermined mixing ratio is added to obtain the output of the mixed output reception beamformer unit 104C. These mixing ratios may be specified by the operator. Only one of them may be output according to the operator's designation.

<Effect>
In the ultrasonic diagnostic apparatus 100B according to the third embodiment and the ultrasonic diagnostic apparatus 100C according to the first modification, the setting method of the reception aperture Rx is adaptively or appropriately set with respect to the characteristics of the examination region. By configuring the reception beamformer so as to be able to adapt, it is possible to ensure uniform spatial resolution even in a wide observation region while maintaining high spatial resolution locally in accordance with the characteristics of the examination site.

  In the ultrasonic diagnostic apparatus 100 according to the first embodiment described above, the reception aperture Rx is expanded by using the transmission-synchronized reception beamformer 104, and the reflected wave reflected from the observation point P toward a wide angle is picked up. Can be reflected in the image to qualitatively improve the spatial resolution. Therefore, in the ultrasonic diagnostic apparatus 100, the spatial resolution can be made uniform in a wide observation region by a virtual wide receiving aperture. Therefore, for example, it is effective for an examination site such as an organ where the intensity of reflected waves is relatively uniform and there is no extreme intensity distribution. By expanding the receiving aperture Rx, spatial resolution uniformity can be improved in a wide observation area, and high image quality can be obtained in a wide observation area. Therefore, when searching for a diseased part in a subject, a specific examination target is predetermined. It is because it adapts by the inspection which is not. On the other hand, the ultrasonic diagnostic apparatus 100 may pick up a wide range of noise signals from other than the observation point P depending on the characteristics of the examination site and the like.

  On the other hand, in the ultrasonic diagnostic apparatus 100A according to the second embodiment, the position of the reception aperture Rx varies in the horizontal axis direction with respect to the observation point P by using the observation point synchronization type reception beamformer 104A. do not do. Therefore, compared to the configuration of the ultrasonic diagnostic apparatus 100, reception beam forming can be performed with respect to the same observation point P using a narrow reception aperture Rx. As a result, high spatial resolution and signal S / N ratio can be realized locally. For example, a reflected wave having a high local intensity such as a polyp is generated, and the applicability is high with respect to an examination site where an examination target is clear. This is because if the reception aperture Rx is not enlarged, a high spatial resolution and a signal S / N ratio can be realized locally, and high image quality can be obtained. On the other hand, in the ultrasonic diagnostic apparatus 100A, when the reception aperture Rx and the transmission focus point F are separated in the horizontal axis direction, the reception aperture Rx receives compared to the case where the transmission focus point F is close to the horizontal axis direction. Since the sum of the received signal energy of the reflected waves is reduced, the reception sensitivity and the signal S / N ratio may be deteriorated depending on the characteristics of the examination site or the like.

  On the other hand, in the ultrasonic diagnostic apparatus 100B according to the third embodiment and the ultrasonic diagnostic apparatus 100C according to the first modification, the optimal reception aperture Rx setting method is adapted to the characteristics of the examination region and the like. The reception beamformer unit is configured so that it can be set according to the selection by the user or the characteristics of the reception signal. Therefore, it is possible to secure uniform spatial resolution even in a wide observation area while maintaining high spatial resolution in some places, adapting to the characteristics of the examination site, etc., and higher resolution than before in the entire ultrasonic irradiation area It is possible to generate a high-quality ultrasonic image in which noise is further suppressed.

<Modification 2>
The ultrasonic diagnostic apparatus according to Modification 2 further uses a reception signal obtained by A / D converting an electrical signal based on the reflected ultrasound received by the probe as an input in the mixed output reception beamformer unit 104C according to Modification 1. It is characterized by that. The Tx / Rx weight signal calculation unit 701A performs feature extraction from the received signal, and adopts a configuration in which the weight signal is adaptively changed based on the feature.

  FIG. 15 is a schematic diagram for explaining an input signal of the Tx / Rx weight signal calculation unit 701A in the reception beamformer unit of the ultrasonic diagnostic apparatus according to the second modification. The mixed output reception beamformer unit of this example is radiated from the transmission aperture Tx, reflected at the observation point Pij at an arbitrary position in the ultrasonic irradiation region Ax, and the reception aperture Rx at the position closest to the observation point Pij. The received signal based on the reflected ultrasonic wave reaching the transducer Rp is used as the input signal. The inventors have found that the received signal values for the transducers Rp represented as propagation paths 801, 802, and 803 in FIG. 15 have a high correlation with the signal after the received beamformer. For example, based on the sum of the paths 801, 802, and 803, when the reception signal value for the delayed transducer Rp is a large value, the signal after the reception beamformer often has a large value. Therefore, the control of the Tx / Rx weight calculation unit 701A can be easily performed using this feature.

  As shown in the first modification, both the transmission synchronization type reception beamformer 104 and the observation point synchronization type reception beamformer 104A are operated, and the Tx / Rx weights are output using the output results after phasing addition. The weight can also be calculated by the calculation unit 701A. However, in that case, it is necessary to operate two beam formers, and a high calculation capability is required for the equipment. As a simpler embodiment with less calculation load, the received signal value before phasing addition for the transducer Rp that has been delayed based on the sum of the propagation paths 801, 802, and 803 is used as a determination value, and based on the determination value. Weights can be calculated.

  For example, when the determination value is larger than a predetermined threshold A, the mixed output reception beamformer unit directly uses the output of the observation point synchronization type reception beamformer 104A as the output of the reception beamformer unit. On the other hand, when the determination value is smaller than the predetermined threshold B, the mixed output reception beamformer unit uses the output of the transmission synchronization type reception beamformer 104 as it is as the output of the reception beamformer unit. When the determination value is between the threshold value A and the threshold value B, the mixing ratio is derived by a predetermined method, the mixing output unit 704A performs output mixing based on the mixing ratio, and the mixing output reception beamformer unit Can be output.

If the threshold A and the threshold B are set to the same value, the Tx / Rx weight calculation unit 701A operates as a switch, and the mixed output unit 704A outputs the output of one of the selected beamformers as a mixed output reception beamformer. Output as part. In this case, the same operation as that of the selective output reception beamformer unit according to the actual form 3 can be performed.
If the mixed output reception beamformer configured as described above is used, a simpler processing method with less calculation load can be adopted, so that a simple circuit configuration can be selected according to the selection by the operator or the characteristics of the reception signal. It is possible to set an optimal receive beamforming method. Therefore, it is possible to generate a high-quality ultrasonic image with higher resolution and lower noise than the conventional ultrasonic irradiation region.

<Other variations>
Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and the following cases are also included in the present invention.
For example, the present invention may be a computer system including a microprocessor and a memory, the memory storing the computer program, and the microprocessor operating according to the computer program. For example, it may be a computer system that has a computer program of the diagnostic method of the ultrasonic diagnostic apparatus of the present invention and operates according to this program (or instructs the connected parts to operate).

  In addition, all or part of the above-described ultrasonic diagnostic apparatus and all or part of the beam forming unit may be configured by a computer system including a recording medium such as a microprocessor, ROM, RAM, and a hard disk unit. It is included in the present invention. The RAM or hard disk unit stores a computer program that achieves the same operation as each of the above devices. Each device achieves its function by the microprocessor operating according to the computer program.

  In addition, some or all of the constituent elements constituting each of the above-described devices may be configured by one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip, and specifically, a computer system including a microprocessor, ROM, RAM, and the like. . These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. Note that an LSI may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. The RAM stores a computer program that achieves the same operation as each of the above devices. The system LSI achieves its functions by the microprocessor operating according to the computer program. For example, the present invention includes a case where the beam forming method of the present invention is stored as an LSI program, and the LSI is inserted into a computer to execute a predetermined program (beam forming method).

  Note that the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable GateArray) that can be programmed after manufacturing the LSI or a reconfigurable processor (ReConfigurable Processor) that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology.
Moreover, you may implement | achieve part or all of the function of the ultrasound diagnosing device based on each embodiment, when processors, such as CPU, run a program. It may be a non-transitory computer-readable recording medium in which a program for executing the diagnostic method of the ultrasonic diagnostic apparatus or the beam forming method is recorded. By recording and transferring a program or signal on a recording medium, the program may be executed by another independent computer system, or the program can be distributed via a transmission medium such as the Internet. Needless to say.

In the ultrasonic diagnostic apparatus according to the above embodiment, the data storage unit that is a storage device is included in the ultrasonic diagnostic apparatus. However, the storage apparatus is not limited to this, and the semiconductor memory, hard disk drive, optical disk drive, magnetic A configuration in which a storage device or the like is externally connected to the ultrasonic diagnostic apparatus may be employed.
In addition, division of functional blocks in the block diagram is an example, and a plurality of functional blocks can be realized as one functional block, a single functional block can be divided into a plurality of functions, or some functions can be transferred to other functional blocks. May be. In addition, functions of a plurality of functional blocks having similar functions may be processed in parallel or time-division by a single hardware or software.

In addition, the order in which the above steps are executed is for illustration in order to specifically describe the present invention, and may be in an order other than the above. Also, some of the above steps may be executed simultaneously (in parallel) with other steps.
In addition, the probe and the display unit are connected to the ultrasound diagnostic apparatus from the outside, but these may be integrated in the ultrasound diagnostic apparatus.

  Moreover, in the said embodiment, the probe showed the probe structure with which the several piezoelectric element was arranged in the one-dimensional direction. However, the configuration of the probe is not limited to this, and for example, a two-dimensional array transducer in which a plurality of piezoelectric transducer elements are arranged in a two-dimensional direction or a plurality of transducers arranged in a one-dimensional direction are mechanically Alternatively, an oscillating ultrasonic probe that oscillates and acquires a three-dimensional tomographic image may be used, and can be appropriately used depending on the measurement. For example, when using a two-dimensionally arranged probe, the irradiation position and direction of the ultrasonic beam to be transmitted can be controlled by individually changing the timing of applying voltage to the piezoelectric transducer and the value of the voltage. .

  The probe may include a part of functions of the transmission beamformer unit and the reception beamformer unit. For example, a transmission electric signal is generated in the probe based on a control signal for generating a transmission electric signal output from the transmission beamformer unit, and the transmission electric signal is converted into an ultrasonic wave. In addition, it is possible to adopt a configuration in which the reflected ultrasonic wave received by the reception beamformer unit is converted into a reception electric signal, and the reception signal is generated based on the reception electric signal in the probe.

Moreover, you may combine at least one part among the functions of the ultrasound diagnosing device which concerns on each embodiment, and its modification. Furthermore, all the numbers used above are exemplified for specifically explaining the present invention, and the present invention is not limited to the illustrated numbers.
Furthermore, various modifications in which the present embodiment is modified within the range conceivable by those skilled in the art are also included in the present invention.

≪Summary≫
As described above, the ultrasonic signal processing apparatus according to the present embodiment transmits an ultrasonic wave from the ultrasonic probe 101 to the subject, and generates an acoustic line signal from the received signal based on the obtained reflected ultrasonic wave. The ultrasonic signal processing device 150 includes an ultrasonic signal processing circuit 151, and the ultrasonic signal processing circuit 151 is a first transducer array that corresponds to all or part of the plurality of transducers in the ultrasonic probe 101. A transmission unit 1031 that performs ultrasonic transmission from a receiver, a reception unit 1041 that generates a reception signal sequence for each transducer based on reflected ultrasound from a subject obtained by the plurality of transducers, and a plurality of transducers The receiving aperture setting unit 1042 that selects the second transducer array whose column center coincides with the column center of the first transducer array, and within a range where the ultrasonic wave transmitted in the subject reaches Located A transmission time calculation unit 1043 for calculating a transmission time until the transmitted ultrasonic wave reaches the observation point P in the subject, and a reflected wave from the observation point P is the second transducer array. The received ultrasonic wave is reflected at the observation point P from the sum of the transmission time and the reception time, and the reception time calculation unit 1044 for calculating the reception time to reach each of the reception vibrators included in the reception vibrator. It corresponds to the delay amount from the delay amount calculation unit 1045 that calculates the total propagation time to reach and calculates the delay amount for each reception transducer based on the total propagation time, and the received signal string for each reception transducer. A delay processing unit 1046 for identifying a reception signal value and an addition unit 1048 for generating an acoustic line signal for the observation point P based on the reception signal value identified corresponding to each reception transducer are provided. . Further, the adding unit 1048 may be configured to add received signal values identified corresponding to each receiving transducer.

With this configuration, it is possible to generate a high-quality ultrasonic image with higher resolution and lower noise than the conventional ultrasonic irradiation region.
Further, in another aspect, there is further provided a weight calculation unit 1047 for calculating a weight sequence for each receiving transducer so that the weight for the transducer located at the center of the second transducer column is maximized, and an addition unit 1048. The configuration may be such that the received signal value identified corresponding to each receiving transducer is multiplied by the weight for each receiving transducer and added.

With this configuration, phasing and addition can be performed at different reception apertures for each transmission event, and the effect of reception processing using a wider reception aperture can be obtained, and spatial resolution can be made uniform over a wide observation area. Can do.
In another aspect, the reception aperture setting unit is the first reception aperture setting unit 1042, the reception time calculation unit is the first reception time calculation unit 1044, the delay amount calculation unit is the first delay amount calculation unit 1045, the delay When the processing unit is the first delay processing unit 1046, the addition unit is the first addition unit 1048, the reception transducer is the first reception transducer, and the acoustic line signal is the first acoustic line signal, the subject The third transducer array is selected so that the column center coincides with the transducer most spatially close to the observation point P for a plurality of observation points located within the reach of the transmitted ultrasonic wave. Second reception aperture setting unit 1042A and a second reception time calculation unit that calculates a reception time when the reflected wave from the observation point P reaches each of the second reception transducers included in the third transducer array 1044 and the sum of transmission time and reception time. A total propagation time until the sound wave is reflected at the observation point P and reaches each second receiving transducer is calculated, and a delay amount for each second receiving transducer is calculated based on the total propagation time. Corresponding to the delay amount calculation unit 1045, the second delay processing unit 1046 for identifying the reception signal value corresponding to the delay amount from the reception signal sequence for each second reception transducer, and each second reception transducer. And a second addition unit 1048 that generates a second acoustic line signal for the observation point P based on the received signal value identified in this way. Further, the second adder 1048 may be configured to add received signal values identified corresponding to the respective second receiving transducers.

With such a configuration, the position of the reception aperture is not synchronized with the transmission event that changes (moves) the transmission focus point F in the horizontal axis direction, and the same reception aperture with respect to the same observation point P even in different transmission events. The phasing addition can be performed at.
Further, in another aspect, a weight calculation unit 1047 is further provided that calculates a weight sequence for each second receiving transducer so that the weight for the transducer located at the center of the third transducer column is maximized, The second adding unit 1048 may be configured to add the received signal value identified corresponding to each second receiving transducer by multiplying the weight for each second receiving transducer.

With such a configuration, the reflected wave from the observation point P can be applied to a transducer having a smaller distance from the observation point P, so that a larger weight sequence can be applied. However, the reflected wave can be received with the highest sensitivity to the observation point P. As a result, high spatial resolution and signal S / N ratio can be realized locally.
In another aspect, the Tx / Rx selection signal calculation unit 701 further selects either the first acoustic line signal or the second acoustic line signal, and the first acoustic line signal or the second acoustic line signal based on the selection result. The configuration may include a selection output unit 704 that outputs any one of the two acoustic line signals. The Tx / Rx selection signal calculation unit 701 may be configured to select either the first acoustic line signal or the second acoustic line signal based on an operation input from the operator or a preset condition. Good. Further, the Tx / Rx selection signal calculation unit 701 may be configured to select either the first acoustic line signal or the second acoustic line signal based on the feature amount of the received signal. In another aspect, the Tx / Rx selection signal calculation unit determines the presence or absence of a puncture needle based on the received signal, and selects the first acoustic line signal when determining that the puncture needle is present. It may be configured to. At this time, the Tx / Rx selection signal calculation unit 701 determines the presence or absence of the puncture needle based on whether or not the mirror structure is detected based on the received signal, and if the mirror structure is detected and the puncture needle is present. If it is determined, the first acoustic line signal may be selected. In addition, the Tx / Rx selection signal calculation unit 701 selects either the first acoustic line signal or the second acoustic line signal based on the first acoustic line signal and / or the second acoustic line signal. It may be. Furthermore, a Tx / Rx weight calculator 701A that calculates weights for each of the first acoustic line signal and the second acoustic line signal, and the first acoustic line signal and the second acoustic line using the weights. A configuration including a mixed output unit 704 </ b> A that outputs a result obtained by multiplying a signal by a weight for each signal and adding the result may be possible. Further, the Tx / Rx weight calculation unit 701A calculates a weight for each of the first acoustic line signal and the second acoustic line signal with respect to the observation point P based on an operation input from the operator or a preset condition. It may be configured to. Further, the Tx / Rx weight calculation unit 701A may be configured to calculate the weight for each of the first acoustic line signal and the second acoustic line signal with respect to the observation point P based on the feature amount of the received signal. In addition, the Tx / Rx weight calculation unit 701A performs each of the first acoustic line signal and the second acoustic line signal for the observation point P based on the first acoustic line signal and the second acoustic line signal for the observation point P. The structure which calculates the weight with respect to may be sufficient.

  With such a configuration, the reception beamformer unit is configured so that the optimal setting method of the reception aperture Rx can be set according to the selection by the operator or the characteristics of the reception signal in accordance with the characteristics of the examination site. Yes. Therefore, it is possible to secure uniform spatial resolution even in a wide observation area while maintaining high spatial resolution locally, adapting to the characteristics of the examination site, etc., and higher resolution than before in the entire ultrasonic irradiation area It is possible to generate a high-quality ultrasonic image with more suppressed noise.

In another aspect, the feature amount includes a reception signal based on the reflected ultrasonic wave from the observation point P identified corresponding to the first reception transducer having the smallest delay amount, and the first delay amount having the smallest delay amount. The structure calculated based on the received signal value identified corresponding to 2 receiving vibrators may be sufficient.
With such a configuration, by adopting a simpler processing method with less calculation load, it is possible to set an optimal receive beamforming method according to the selection by the operator or the characteristics of the received signal with a simple circuit configuration. .

In another aspect, when the transducer included in the first transducer array is a part of a plurality of transducers in the ultrasonic probe, the transmission unit 1031 further includes a part of the plurality of transducers. In order to perform the ultrasonic transmission sequentially from the transducer array different from the first transducer array, the transducer array used for each ultrasound transmission is different.
The adding unit 1048 may be configured to synthesize a plurality of acoustic line signals for observation points at the same position generated based on different ultrasonic transmissions to generate an acoustic line signal for the observation point.

In another aspect, the transmission unit 1031 may be configured to perform ultrasonic transmission from all of the plurality of transducers in the ultrasonic probe by sequentially performing ultrasonic transmission with different transducer rows to be used. Good.
Moreover, in another aspect, the ultrasonic diagnostic apparatus comprised so that the ultrasonic probe 101 was connectable may be sufficient.

With such a configuration, it is possible to provide an ultrasonic diagnostic apparatus capable of generating a high-quality ultrasonic image having higher resolution and suppressing noise over the entire ultrasonic irradiation region.
<Supplement>
Each of the embodiments described above shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, steps, order of steps, and the like shown in the embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the embodiment, steps that are not described in the independent claims indicating the highest concept of the present invention are described as arbitrary constituent elements constituting a more preferable form.

Further, for easy understanding of the invention, the scales of the components shown in the above-described embodiments may be different from actual ones. The present invention is not limited by the description of each of the above embodiments, and can be appropriately changed without departing from the gist of the present invention.
Furthermore, in the ultrasonic diagnostic apparatus, there are members such as circuit components and lead wires on the substrate, but various modes can be implemented based on ordinary knowledge in the technical field regarding electrical wiring and electrical circuits. Since it is not directly relevant to the description of the present invention, the description is omitted. Each figure shown above is a schematic diagram, and is not necessarily illustrated strictly.

  The ultrasonic signal processing device, the ultrasonic diagnostic device, the ultrasonic signal processing method, and the computer-readable non-transitory recording medium according to the present disclosure are useful for improving the performance of the conventional ultrasonic diagnostic device, particularly for improving the image quality. is there. The present disclosure can be applied not only to ultrasonic waves but also to uses such as sensors using a plurality of array elements.

DESCRIPTION OF SYMBOLS 100 Ultrasonic signal processing circuit 101, 201 Probe 101a, 201a Ultrasonic vibrator 102 Multiplexer part 103 Transmission beam former part 1031 Transmission part 104 Reception beam former part (transmission synchronous beamformer part)
104A Receive beamformer unit (observation point synchronous beamformer unit)
1041 Reception unit 1042 Reception aperture setting unit (first reception aperture setting unit)
1042A Reception aperture setting unit (second reception aperture setting unit)
1043 Transmission time calculation unit (first transmission time calculation unit, second transmission time calculation unit)
1044 Reception time calculation unit (first reception time calculation unit, second reception time calculation unit)
1045 Delay amount calculation unit (first delay amount calculation unit, second delay amount calculation unit)
1046 Delay processing unit (first delay processing unit, second delay processing unit)
1047 Weight calculation unit (first weight calculation unit, second weight calculation unit)
1048 Adder (first adder, second adder)
DESCRIPTION OF SYMBOLS 105 Ultrasonic image generation part 150 Ultrasonic signal processing apparatus 106 Display part 107 Data storage part 202 Reception beamformer part 701 Tx / Rx weight calculation part 704 Selection output part 704A Mixing output part

Claims (16)

An ultrasonic probe having a plurality of transducers;
A transmitter for performing ultrasonic transmission from a first transducer array corresponding to all or part of the plurality of transducers;
A receiving unit that generates a reception signal sequence for each transducer of the second transducer array in accordance with a signal based on the reflected ultrasound obtained by the second transducer array corresponding to all or part of the plurality of transducers When,
A delay amount generating unit that generates a plurality of delay amounts corresponding to the plurality of transducers;
A delay processing unit that delays a received signal sequence for each transducer based on the plurality of delay amounts;
The delay amount generator
In one transmission event, the ultrasonic waves transmitted is about one observation point you located within reaching generates a transmission time until the ultrasonic waves transmitted is reached before Symbol one observation point A transmission time generator;
And a reception time generation unit for generating a reception time reflected ultrasonic wave to reach each of the transducers in the second oscillator column from the previous SL one observation point,
Based on the transmission time generated by the transmission time generation unit and the reception time for each transducer of the second transducer array generated by the reception time generation unit , generating a delay amount for each vibration children of the second oscillator column,
The transmission time generation unit generates the transmission time as data shared between the transducers of the second transducer array.
Ultrasound diagnostic device. The delay processing unit identifies a received signal value corresponding to the delay amount from the received signal sequence for each transducer of the second transducer sequence, and for each observation point based on the identified received signal value Generate acoustic line signals,
The ultrasonic diagnostic apparatus according to claim 1. The transmission time generating unit, the transmission reference point, based on the measurement point focus point and before Symbol view, to generate the transmission time,
The ultrasonic diagnostic apparatus according to claim 1 or 2. The reception time generation unit is based on the distance between the observation point and the transducer of the second transducer array,
Generating the reception time;
The ultrasonic diagnostic apparatus of any one of Claim 1 to 3. The delay generator is between when the transmission generated by the transmission time generating unit, by adding between the time the reception of each transducer of said second oscillator column, the second oscillator Generate a delay for each oscillator in the column ,
The ultrasonic diagnostic apparatus of any one of Claim 1 to 4. The reception unit generates the reception signal sequence in response to a signal based on reflected ultrasound from the subject obtained by the second transducer array,
The observation point is set in the subject;
The ultrasonic diagnostic apparatus of any one of Claim 1 to 5. Ultrasonic transmission is performed from the first transducer array corresponding to all or part of the plurality of transducers of the ultrasonic probe;
In response to a signal based on the reflected ultrasound obtained by the second transducer array corresponding to all or a part of the plurality of transducers, a reception signal sequence for each transducer of the second transducer array is generated,
Generating a plurality of delay amounts corresponding to the plurality of vibrators;
Based on the plurality of delay amounts, the received signal sequence for each transducer is delayed.
An ultrasonic image generation method for generating an ultrasonic image based on the signal after the delay processing,
The generation of the delay amount is
In one transmission event, for one observation point you located within the ultrasonic wave transmitted arrives, the ultrasonic waves transmitted generates a transmission time to reach before Symbol one observation point ,
Generates a reception time reflected ultrasound from the previous SL one observation point reaches each of the transducers in the second oscillator column,
A transmission time said generated every second on the basis of said reception time which is generated for each transducer of the transducer column, said one vibration children of the second oscillator column according to transmission events Generates a delay amount of
The generation of the transmission time generates the transmission time as data shared between the transducers of the second transducer array.
Ultrasonic image generation method. In the delay processing, a received signal value corresponding to the delay amount is identified from the received signal sequence for each transducer of the second transducer sequence, and an acoustic for each observation point is based on the identified received signal value. Generate line signals,
The ultrasonic image generation method according to claim 7. The transmission time, the transmission reference point is generated based on the focus point and measuring point prior Symbol view,
The ultrasonic image generation method according to claim 7 or 8. The reception time is generated based on a distance between the observation point and the transducer of the second transducer array.
The ultrasonic image generation method according to any one of claims 7 to 9. The amount of delay, while the time of transmission of the generated by adding between when the reception of each transducer of said second oscillator columns are generated for each transducer of said second oscillator column The
The ultrasonic image generation method according to claim 7. The received signal sequence is generated according to a signal based on reflected ultrasound from the subject obtained by the second transducer array,
The observation point is set in the subject;
The ultrasonic image generation method according to claim 7. The transmission time generation unit generates the transmission time until the transmitted ultrasonic wave reaches the one observation point only once in the one transmission event.
  The ultrasonic diagnostic apparatus according to claim 1. The transmission time generation unit generates the transmission time only once for each transmission event for the observation point,
The delay processing unit generates an acoustic line signal for the observation point based on the reception signal sequence for each transducer of the second transducer sequence in a plurality of transmission events.
The ultrasonic diagnostic apparatus according to claim 13 . In the generation of the transmission time, the transmission time until the transmitted ultrasonic wave reaches the one observation point is generated only once in the one transmission event.
  The ultrasonic image generation method according to any one of claims 7 to 12. In the generation of the transmission time, for the observation point, the transmission time is generated only once for each transmission event,
In the delay processing, an acoustic line signal for the observation point is generated based on the reception signal sequence for each transducer of the second transducer sequence in a plurality of transmission events.
The ultrasonic image generation method according to claim 15.

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