KR20090057837A - Ultrasound synthetic aperture beamformer and ultrasound image apparatus using the beamformer - Google Patents

Abstract

An ultrasound synthetic aperture beamformer and ultrasound image apparatus using the same are provided to display a clean ultrasonic image in real time by using SAFT(Synthetic Aperture Focusing Technique). A synthetic aperture beamformer(1) has N channels and M synthetic transmit apertures. The synthetic aperture beamformer comprises the beamformer with n single-channels. The single channel beamformer outputs M data. A channel selection switch unit(100), a plurality of interpolators(110), a plurality of memories(120), a plurality of time delay calculators(130), a plurality of demultiplexers(140), and plurality of apodization calculators(150).

Description

Ultrasound Synthetic Aperture Beamformer and Ultrasound image apparatus using the beamformer

The present invention relates to a composite aperture beamformer of an ultrasonic imaging apparatus. More specifically, the composite aperture beamformer enables a commercialization by applying a synthetic aperture focusing technique to display a real-time image while simplifying hardware. The present invention relates to an applied ultrasonic imaging apparatus.

The ultrasound imaging apparatus converts an electric signal into an ultrasonic wave by using a piezoelectric transducer, receives an ultrasonic signal reflected from an object to be observed, converts it into an electric signal, and then processes the signal into an image. To pass.

FIG. 1 is a block diagram of an overall B-mode imaging apparatus in a general ultrasound imaging apparatus. Referring to FIG. 1, the ultrasonic transducer receives an electrical signal from a transmitter and transmits ultrasonic waves, converts the received ultrasonic waves into electrical signals, and transmits the ultrasonic signals to the receiver. Using the received signal, the reception focusing unit generates a scan line, and a plurality of scan lines obtained through this method form a 2D cross-sectional image in real time through an echo signal processing unit and a digital scan line converter.

In an ultrasound imaging apparatus, a reception dynamic focusing technique is generally used as a method of focusing an ultrasound transducer using an array transducer arranged in an array. FIG. 2 is a block diagram illustrating a structure of a reception dynamic beamformer having an N channel as a reception dynamic beamformer using a conventional reception dynamic focusing technique. FIG. 3 is a channel diagram of the reception dynamic beamformer of FIG. 2. This is a block diagram showing the beamformer in detail. 4 is a diagram exemplarily illustrating a scanning process for 10 scan lines of the aforementioned reception dynamic beamformer. Referring to FIG. 4, the reception dynamic beamformer transmits an ultrasonic signal once to generate one scan line, and the generated scan lines are all positioned at the center of each array transducer. In this case, the frame rate is shown in Equation 1.

Where FR, D _MAX , L and c represent the frame rate, the maximum depth of the image, the number of scan lines in one section and the ultrasound velocity in the human body. Since the reception dynamic focusing technique can focus on a fixed point at the time of transmission, the resolution of the image outside the transmission focusing point is deteriorated.

In order to overcome this drawback, a synthetic aperture focusing technique capable of bidirectional dynamic focusing has been proposed. The basic principle of the general synthetic aperture focusing technique is to focus on the transmission time delay and the reception time delay by receiving the reflected signal after transmitting the unfocused ultrasonic signal. In other words, the synthetic aperture focusing technique transmits ultrasonic waves once and receives them with N transducers and focuses them, but transmits these processes M times and synthesizes the focused signals to form a single scan line. N is the number of channels and M is the number of synthesized transmission apertures.

5A and 5B are diagrams illustrating input and output states of a reception dynamic beamformer using a reception dynamic focusing technique and a composite aperture beamformer using a composite aperture focusing technique, respectively. Such synthetic aperture beamformers have not been commercialized yet because they require higher hardware complexity than receive dynamic beamformers.

When the composite aperture beamformer is implemented by the above-described reception dynamic beamformer, transmission and reception should be performed as shown in FIG.

Here, M denotes the number of transmissions synthesized to generate one scan line, that is, the number of synthesized transmission apertures, and L denotes the number of scan lines. When transmitting and receiving according to the synthetic aperture technique as shown in FIG. 6, since the frame rate is M times lower than that of the conventional beam focusing method, it is difficult to display an image in real time. By the way, referring to FIG. 6, when the scan line numbers are 2-3, 3-2, and 4-1, it can be seen that different scan lines are generated with the same transmit / receive data. Therefore, as shown in FIG. 7, if a plurality of conventional reception dynamic beamformers are used to beam-focus on several scan lines simultaneously, the frame rate is expressed by Equation 3 below.

When implementing a composite aperture beamformer having a composite transmission aperture M using M conventional reception dynamic beamformers, the memory structure for the input / output data is required. When an input terminal of a conventional receiving dynamic beamformer is called a raw data (RD) stage and an output terminal is a BD (beamformed data) stage, a memory structure may be located at an RD stage or a BD stage.

The RD stage memory structure may be configured as shown in FIG. 8. In this case, in order to generate one scan line by using the synthetic aperture technique, it is necessary to have all data transmitted and received M times. Therefore, data transmitted and received M times must be processed simultaneously using M different beam focusing units. When the processed data is added to the end, it becomes the output of the composite diameter beam focusing unit in which the bidirectional dynamic focusing is performed.

The BD stage memory structure can be configured as shown in FIG. The data beam-focused with the received data obtained after transmitting with one transducer can be added by the number of synthetic transmission apertures M to complete one scan line. Therefore, the received data generated in one transmission becomes the input of M reception dynamic beamformers. Receiving dynamic beamformers receiving the data output the focused data, and the data is stored in the FIFO connected to each receiving dynamic beamformer, and then stored in the FIFO in addition to the next beamformer output data. The completed scanning line data are generated at different times, so outputting them sequentially produces the composite diameter beam focusing unit.

The RD stage memory structure requires N times as many FIFOs as the BD stage memory structure. Therefore, in the present invention, since raw data acquisition is not required, a BD stage memory structure capable of reducing hardware may be used.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a synthetic aperture beamformer that can be commercialized by simplifying the structure of hardware.

Another object of the present invention is to provide a synthetic aperture beamformer capable of providing a clear ultrasound image in real time.

Still another object of the present invention is to provide a synthetic aperture beamformer that can be applied to commercially available ultrasonic equipment as it is.

A feature of the present invention for achieving the above-described technical problem relates to a composite aperture beamformer having a number of channels N and a composite transmission aperture number M, wherein the composite aperture beamformer has a one-channel beamformer in parallel by the number of channels (N). Characterized in that connected,

The one-channel beamformer outputs data equal to the number of synthetic transmission apertures (M),

A channel selection switch unit for selecting a corresponding channel;

A plurality of interpolators connected in parallel to the channel select switch;

A plurality of memories connected in parallel to the output terminals of each interpolator;

A plurality of time delay calculators for calculating time delay values for data stored in memories connected to the interpolator and providing them to respective memories;

A plurality of demultiplexers for demultiplexing and outputting data of memories included in the same synthesized aperture;

And a plurality of window coefficient calculators for multiplying and outputting window coefficients for the output signal of the demultiplexer.

The time delay calculator of the composite aperture beamformer having the above-described characteristics sets and registers the case where the transmission delay time and the reception delay time are the same in advance, and determines whether the reception delay time is the same as the transmission delay time when calculating the time delay. If the reception delay time is the same as the transmission delay time, it is preferable to use the transmission delay time as it is without calculating the reception delay time.

The window coefficient calculator of the composite aperture beamformer having the above-described characteristics is preferably provided with a table of the window coefficients for the channel from one end to the center along the transmission aperture direction and used repeatedly according to the symmetry of the window coefficients. .

Preferably, four interpolators are provided in the one-channel beamformer having the above-described characteristics.

According to another aspect of the present invention, an ultrasound imaging apparatus includes the aforementioned synthetic aperture beamformer and provides an ultrasound image of an inspection area.

An array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to the inspection area and receiving an ultrasonic signal reflected from the inspection area;

A composite aperture beamformer for beamforming a scanning line by controlling transmission and reception of an ultrasonic signal to the array transducer;

A display unit;

A controller which controls the synthesized aperture beamformer to provide an ultrasound image of the inspection area to the display unit; And

And a user input unit configured to receive information about an ROI of a test area from a user, wherein the controller drives the composite aperture beamformer by a reception dynamic focusing method when information about the ROI is input through the user input unit. Display an ultrasound image of the entire inspection area on the display unit, and then drive the composite aperture beamformer with a synthetic aperture focusing technique on the ROI to obtain an ultrasound image of the ROI of the inspection area. Display on the image.

According to another aspect of the present invention, an ultrasound imaging apparatus includes the above-described synthetic aperture beamformer and provides an ultrasound image of an inspection area.

An array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to the inspection area and receiving an ultrasonic signal reflected from the inspection area;

A composite aperture beamformer for beamforming a scanning line by controlling transmission and reception of an ultrasonic signal to the array transducer;

A display unit;

A controller which controls the synthesized aperture beamformer to provide an ultrasound image of the inspection area to the display unit;

The control unit presets a limit position line at a position spaced from the array transducer in the inspection area in advance, and the control unit drives the composite aperture beamformer by a receiving dynamic focusing technique to the entire inspection area. After displaying the ultrasound image on the display unit, the synthesized aperture beamformer is driven by a synthetic aperture focusing technique for the remaining region except the region from the array transducer to the limit position line to obtain an ultrasound image of the corresponding region. Display on the ultrasound image of the display unit.

FIG. 17 is a diagram comparing hardware resources of a conventional synthetic aperture focused beamformer using a conventional N-channel receive dynamic beamformer and M N-channel receive dynamic beamformers. 17, it can be seen that the conventional synthetic aperture focusing beamformer requires M times as much hardware as the N-channel receiving dynamic beamformer.

FIG. 18 is a table comparing the hardware resources of the conventional composite aperture beamformer of N-channel having a composite transmission aperture number M and the composite aperture beamformer according to the present invention. Most of the hardware constituting the beamformer is a memory, a multiplier, and a root operator. Therefore, only three types of hardware are compared. Since most of the hardware is reduced by M times, the larger the number of synthesized transmission diameters, the better the efficiency compared to the conventional method. Currently, a general ultrasonic system commercially available is receiving dynamic focus using 64 or more transducers.

19 compares the hardware resources required for the conventional aperture beamformer according to the present invention with the conventional transmission aperture size of 64. FIG. Compared to the previous method, all hardware complexity is reduced to less than half. The time delay calculator, which takes the largest amount of calculation in the beamformer, can be confirmed to be reduced by more than 98% by sharing the same time delay value. The composite aperture beamformer according to the present invention has a hardware complexity about four times larger than that of the conventional 64-channel receiving dynamic beamformer. Therefore, the composite aperture beamformer according to the present invention can be implemented with the hardware complexity of four conventional reception beamformers.

In order to implement a real-time system to which the composite aperture technique is applied, the frame rate for real-time imaging can be matched using a number of existing reception beam beamformers. In this case, since the input / output data are not used sequentially, a memory for storing the input / output data is required, and the present invention provides a composite diameter beamformer having a BF stage memory structure in order to efficiently use such a memory.

The present invention eliminates unnecessary parallel parts in order to optimize in the required transmission port direction, and puts the position of the interpolator at the front of the input stage, and the time delay calculator calculates the transmission time delay and the reception time delay separately. The window coefficient calculator reduced the number by half using the symmetry of the window coefficient, and the memory could be effectively reduced by suggesting the constraint of the composite image.

 As a result, according to the present invention, the composite channel beamformer can be implemented using only hardware resources of four conventional reception dynamic beamformers. This removes the cause of the price increase, which was the biggest obstacle to commercialization, and can be applied to actual ultrasonic equipment.

Hereinafter, a synthetic aperture beamformer according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

10 is a block diagram schematically illustrating an internal structure of a composite aperture beamformer having a channel number N and a composite transmission aperture number M according to a preferred embodiment of the present invention. Referring to FIG. 10, a composite aperture beamformer 1 having a channel number N and a composite transmission aperture number M according to a preferred embodiment of the present invention is a one-channel beamformer 10 as many as the channel number N. ) Are connected in parallel.

The one-channel beamformer 10 outputs data corresponding to the synthesized transmission aperture number M, and includes a channel select switch unit 100 for selecting a corresponding channel and a plurality of interpolators connected in parallel to the channel select switch unit. 110, a plurality of memories 120 connected in parallel to the output terminal of each interpolator, a plurality of times to calculate the time delay value for the data stored in the memory connected to the interpolator to provide to each memory Delay calculators 130, a plurality of demultiplexers 140 for demultiplexing and outputting data of memories included in the same composite aperture, and a plurality of window coefficient calculators for multiplying and outputting window coefficients for the output signals of the demultiplexer 150).

The one-channel beamformer is preferably provided with four interpolators. The lowpass filter used in the interpolator is a 64tap FIR filter.

The interolators are connected in parallel by the synthetic transmission aperture number M, and four interpolators are preferably provided for one channel. Time delay resolution is required in an ultrasound system, because it is the center frequency of the ultrasound f ₀ when 16f _0, in the present invention, input data sampled by by having four an interpolation for a single channel, the Nyquist rate (4f ₀₎ 4 times interpolation.

The time delay calculator 130 is for giving a different time delay to each transducer at the time of transmission and reception for beam focusing. Since the time delay calculator 130 is originally provided with M for one channel, N composite beam beamformers should exist in the receiving channel direction and M in the transmission aperture direction, and as a whole, N ㅧ M pieces will be provided. . 11 illustrates a time delay calculation model between a focal point and a transformer. In order to calculate another time delay in the transmission / reception direction, operations such as Equations 4, 5 and 6 are performed in the situation as shown in FIG.

Where t _{TX in} equation (4) Is the transmission time delay, T _dy is the distance in the y-axis direction from the center point to the transmitting array element, and T _dx Is the distance in the x-axis direction from the center point to the transmission array element, R ₀ is the distance from the center point to the focal point, and θ is the deflection angle. T _RX in Equation 5 represents a reception time delay, R _dy represents a distance in the y-axis direction from the center point to the receiving array element, and R _dx represents a distance in the x axis direction from the center point to the receiving array element. The total time delay value to be calculated is t _TOT of Equation 6. One time delay calculator requires six multipliers and two root operators. The calculations performed at this time are R ₀ ㅧ sinθ, R ₀ ㅧ cosθ, (Tdy + R ₀ sinθ) ㅧ (Tdy + R ₀ sinθ), (Tdx + R ₀ cosθ) ㅧ (Tdx + R ₀ cosθ), (Rdy + R ₀ sinθ) ㅧ (Rdy + R ₀ sinθ) and (Rdx + R ₀ cosθ) ㅧ (Rdx + R ₀ cosθ). Since the N 줄이기 M time delay calculations are required to apply the composite aperture technique, the transmission time delay and the reception time delay are calculated separately and the overlapping delay values are unified.

On the other hand, a delay calculator according to another embodiment of the present invention sets and registers the case where the transmission delay time and the reception delay time are the same in advance, and at the time of calculating the time delay, the reception delay time is equal to the transmission delay time. If the reception delay time is the same as the transmission delay time, the transmission delay time is used as it is without calculating the reception delay time. As a result, in the case of the present embodiment, the time delay calculator requires less than M number of time delay calculators.

The scanning lines, which the composite aperture beamformer must construct at the same time, are located in the reception aperture at any time. FIG. 12 exemplarily shows transmission and reception time delay values to be simultaneously calculated by a four-channel composite aperture beamformer having a composite transmission aperture number of four. Where T0, T1, T2, and T3 are the transmission time delay values from the transmission array transducer to the image point, and R0, R1, R2, and R3 are reception time delay values from the image point to each reception array transformer. At this time, since T0 = R0, T1 = R1, T2 = R2, and T3 = R3, only four unidirectional time delay values can simultaneously transmit and receive to four different image points. Four multipliers and one root operator are required to calculate one unidirectional time delay, but multiplication for R ₀ ㅧ sinθ and R ₀ ㅧ cosθ is a common factor to obtain four unidirectional time delay values. In total, we need a total of 2+ (2 ㅧ 4) = 10 multipliers and 4 root operators. On the other hand, when calculating the time delay according to the conventional method, it is necessary to calculate the 16 transmission and reception delay times separately and require 96 multipliers and 32 root operators.

In the time delay calculator according to the present invention, the hardware increases in proportion to the number of channels irrespective of the size of the synthesized transmit aperture, so that the efficiency increases as the size of the synthesized transmit aperture increases.

The receiving aperture window reduces the side lobe size of the ultrasonic beam pattern formed on the field during reception, thereby improving image resolution. The receiving dynamic diameter for f-number adjustment, which is the relationship between the focusing point and the size of the receiving diameter, serves to make the resolution of the entire area uniform. The reception dynamic diameter changes with the depth of the image around the scan line to be constructed as shown in FIG. 13 and gradually increases in size. In this case, in order to apply the receiving aperture window, each receiving transformer must be multiplied by a different window coefficient according to the depth. Each window coefficient calculator contains one SRAM to store the coefficient values, and one ROM for the LUT for the division operation required for the calculation process, and two multipliers.

The window coefficient calculator provided in the 1-channel beamformer multiplies and outputs the window coefficient with respect to the output signal of the demultiplexer provided in the 1-channel beamformer. desirable. Synthetic aperture beamformers apply only to linear scan, curved scan and microcurve scan.

On the other hand, the window coefficient to which the reception dynamic aperture and the reception aperture window are applied shows symmetry according to the position of the scan line to be constructed. Therefore, the window coefficient calculator of the composite aperture beamformer according to another embodiment of the present invention sets only a table of window coefficients for transmission apertures from one end to the center in the transmission aperture direction, and the window coefficients having symmetry are repeatedly It is preferable to use. As a result, since the window coefficient calculator according to the present embodiment is used repeatedly according to symmetry, M / 2 can be provided.

The demultiplexer for demultiplexing and outputting data of memories included in the same synthesized aperture included in the 1-channel beamformer is preferably M.

According to the present invention, the memory required for the input stage is increased by four times. In order to effectively reduce this, it is preferable to limit the ultrasound image to which the synthetic aperture technique is applied. Therefore, first, the image is applied by applying the conventional reception dynamic focusing technique to the entire region, and the bidirectional dynamic focusing is performed by applying the synthetic aperture technique only in the region of interest.

14 is a block diagram illustrating a relationship between an input and an output of a general beamformer. Referring to FIG. 14, the beamformer's role is to pinpoint the signal returned from the desired focal point by applying a time delay to the input x (t) signal expressed as τ (t). Therefore, as shown in FIG. 14, a buffer may be provided at an input terminal to output the output after a predetermined time to enable real-time processing.

In this case, the minimum size of the input buffer required to store the maximum time difference between the signals reflected from one image point and the input to different transducers is stored. On the other hand, it is preferable to use two-port SRAM because the memory must be able to access different data according to the time delay value changed every time.

The two-port SRAM paralleled in the transmission diameter direction of the composite diameter beamformer stores the same input data, but the data required for different scan lines (M) are different, so that two different data can be read at the same time. M port SRAM had to be used. Equation 7 shows the maximum time difference by setting θ = 0 in order to examine the case where the synthetic diameter technique is applicable in Equation 5.

Where Rdy _MAX and Rdx _MAX are values for the position of the transducer furthest from the focal point. In general, since Rdx _MAX is 0 or a very small value, it can be approximated as shown in Equation 8.

In general, a high performance ultrasound system uses 64 channels and the maximum value of Rdy _MAX is about 2 cm, considering that the width between the transducers of the linear transducer is about 0.3 mm (0.3 ㅧ 64 = 19.2mm). When Rdy _MAX is 2cm at the speed c = 1540m / sec, it shows the difference of reception time between transducers according to the image depth (R ₀ ). On the other hand, Figure 16 is a graph showing the size of the RF data buffer required in the case of a system operating at 40MHz.

The 64 channel composite diameter beamformer according to the conventional method had to use 64 ㅧ 64 2-port SRAMs, but the composite diameter beamformer according to the present invention increased four times by arranging the position of the interpolator right behind the input terminal. It became 4 ㅧ 64 ㅧ 64. Basically, with 4x64 2-port SRAMs, no problem occurs when performing fixed transmit / receive beam focusing. Therefore, in one embodiment of the present invention, 4 × 64 2-port SRAMs are used as they are, but instead of the remaining 4 × 64 × 63 2-port SRAMs, 64 additional small capacity multi-output memories are designed.

<Ultrasound imaging device>

Hereinafter, an embodiment of an ultrasound imaging apparatus according to another feature of the present invention will be described in detail. The ultrasonic imaging apparatus according to the present invention includes the above-described synthetic aperture beamformer to provide an ultrasound image of an inspection area. The ultrasonic imaging apparatus includes (1) an array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to an inspection region and receiving an ultrasonic signal reflected from the inspection region, and (2) an ultrasonic signal to the array transducer. (3) a display unit, (4) a control unit for controlling the composite aperture beamformer to provide an ultrasound image of the inspection area to the display unit, and (5) a user. And a user input unit configured to receive information about an ROI from the inspection area.

When the information on the ROI is input through the user input unit, the controller drives the synthesized aperture beamformer by a reception dynamic focusing method to display an ultrasound image of the entire inspection area on a display unit and then displays the ROI. The synthesized aperture beamformer is driven by a synthetic aperture focusing technique to obtain an ultrasound image of a region of interest in the inspection area, and to display the image on the ultrasound image of the display unit.

Hereinafter, another embodiment of the ultrasound imaging apparatus of the present invention will be described. The ultrasonic imaging apparatus according to the present invention includes the above-described synthetic aperture beamformer to provide an ultrasound image of an inspection area. The ultrasonic imaging apparatus includes (1) an array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to an inspection region and receiving an ultrasonic signal reflected from the inspection region, and (2) an ultrasonic signal to the array transducer. And a control unit configured to control transmission and reception of the composite aperture beamformer to beamform the scan line, (3) a display unit, and (4) to control the composite aperture beamformer to provide an ultrasound image of the inspection area to the display unit.

The controller presets a limit position line at a predetermined distance from the array transducer in the inspection region, and the controller drives the synthesized aperture beamformer by a reception dynamic focusing technique to generate an ultrasound image of the entire inspection region. After displaying on the display unit, the synthesized aperture beamformer is driven by a synthetic aperture focusing technique for the remaining regions other than the region from the array transducer to the limit position line to obtain an ultrasound image of the corresponding region. It is displayed in duplicate on the ultrasound image.

The ultrasound imaging apparatus according to the present invention displays a ultrasound image by driving a composite aperture beamformer according to a synthesis aperture focusing technique only in a region of interest set by a user or in a region above a predetermined limit position line, and receives dynamic focus for the remaining regions. By displaying the ultrasound image according to the technique, it is possible to reduce the capacity of the memory.

Although the present invention has been described above with reference to preferred embodiments thereof, this is merely an example and is not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. And differences relating to such modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

Synthetic aperture beamformer according to the present invention can be widely used in ultrasonic diagnostic equipment and the like.

FIG. 1 is a block diagram showing the overall configuration of a B-mode imaging apparatus in a typical ultrasound imaging apparatus.

FIG. 2 is a block diagram illustrating a structure of a reception dynamic beamformer having an N channel as a reception dynamic beamformer using a conventional reception dynamic focusing technique. FIG. 3 is a channel diagram of the reception dynamic beamformer of FIG. 2. This is a block diagram showing the beamformer in detail.

4 is a diagram illustrating a scanning process for 10 scan lines of a conventional receiving dynamic beamformer.

5A and 5B are diagrams illustrating input and output states of a reception dynamic beamformer using a reception dynamic focusing technique and a composite aperture beamformer using a composite aperture focusing technique, respectively.

6 is a diagram illustrating a scanning process for beam focusing using a conventional synthetic aperture beamformer implemented using a reception dynamic beamformer.

7 is a diagram exemplarily illustrating a scanning process for beam focusing on multiple scan lines at the same time using a plurality of conventional reception dynamic beamformers.

8 is a block diagram exemplarily illustrating a structure of a composite aperture beamformer using an RD stage memory structure.

9 is a block diagram illustrating a structure of a composite aperture beamformer using a BD stage memory structure.

10 is a block diagram schematically illustrating an internal structure of a composite aperture beamformer having a channel number N and a composite transmission aperture number M according to a preferred embodiment of the present invention.

11 illustrates a time delay calculation model between a focal point and a transformer.

12 exemplarily shows transmission and reception time delay values to be simultaneously calculated by a four-channel composite aperture beamformer having a composite transmission aperture number of four.

FIG. 13 exemplarily shows a reception dynamic aperture for each scan line. The scan line changes with depth of an image around a scan line to be configured and gradually increases in size.

14 is a block diagram illustrating a relationship between an input and an output of a general beamformer.

FIG. 15 illustrates the difference in arrival time between transducers according to the depth R ₀ of an image when Rdy _MAX is 2cm at an ultrasonic speed c = 1540m / sec.

FIG. 16 is a graph showing the size of an RF data buffer required in a system operating at 40 MHz.

FIG. 17 is a diagram comparing hardware resources of a conventional synthetic aperture focused beamformer using a conventional N-channel receive dynamic beamformer and M N-channel receive dynamic beamformers.

FIG. 18 is a table comparing hardware resources of a conventional composite aperture beamformer of N channels having a synthetic transmission aperture number M and a composite aperture beamformer according to the present invention.

19 compares the hardware resources required for the composite aperture beamformer according to the present invention with the conventional transmission aperture size of 64. FIG.

<Description of Symbols for Main Parts of Drawings>

1: synthetic aperture beamformer

10: 1 channel beamformer

100: channel select switch

110: interpolator

120: memory

130: Time Delay Calculator

140: Demultiplexer

150: Window Coefficient Calculator

Claims (8)

In a composite aperture beamformer having a number of channels N and a composite transmission aperture number M, the composite aperture beamformer includes: 1-channel beamformer is characterized in that connected in parallel by the number of channels (N), The one-channel beamformer outputs data equal to the number of synthetic transmission apertures (M), A channel selection switch unit for selecting a corresponding channel; A plurality of interpolators connected in parallel to the channel select switch; A plurality of memories connected in parallel to the output terminals of each interpolator; A plurality of time delay calculators for calculating time delay values for data stored in memories connected to the interpolator and providing them to respective memories; A plurality of demultiplexers for demultiplexing and outputting data of memories included in the same synthesized aperture; A plurality of window coefficient calculators for multiplying and outputting window coefficients for the output signals of the demultiplexer; Composite aperture beamformer, characterized in that it comprises a. The method of claim 1, wherein the time delay calculator sets and registers a case where the transmission delay time and the reception delay time are the same in advance, and checks whether the reception delay time is the same as the transmission delay time when calculating the time delay. If the reception delay time is the same as the transmission delay time, the synthesized aperture beamformer characterized by using the transmission delay time as it is without calculating the reception delay time. 2. The composite aperture beamformer according to claim 1, wherein the window coefficient calculator sets a table for window coefficients for the channel from one end to the center along the transmission aperture direction. The composite aperture beamformer of claim 1, wherein four interpolators are provided in the one-channel beamformer. The composite aperture beamformer according to claim 1, wherein the demultiplexer for demultiplexing and outputting data of memories included in the same composite aperture included in the one-channel beamformer is M. The synthesized aperture beamformer according to claim 1, wherein the window coefficient calculator for multiplying and outputting a window coefficient with respect to an output signal of the demultiplexer provided in the one-channel beamformer is M / 2. An ultrasound imaging apparatus comprising a composite aperture beamformer according to any one of claims 1 to 6, wherein an ultrasound imaging apparatus provides an ultrasound image of an inspection area. An array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to the inspection area and receiving an ultrasonic signal reflected from the inspection area; A composite aperture beamformer for beamforming a scanning line by controlling transmission and reception of an ultrasonic signal to the array transducer; A display unit; A controller which controls the synthesized aperture beamformer to provide an ultrasound image of the inspection area to the display unit; And A user input unit configured to receive information about an ROI of the inspection area from a user; And when the information on the ROI is input through the user input unit, the controller drives the synthesized aperture beamformer by a reception dynamic focusing method to display an ultrasound image of the entire inspection area on a display unit. And operating the synthesized aperture beamformer with a synthetic aperture focusing technique on the region of interest to obtain an ultrasound image of the region of interest in the inspection region and to display the image on the ultrasound image of the display unit. An ultrasound imaging apparatus comprising a synthetic aperture beamformer according to any one of claims 1 to 6, wherein the ultrasound imaging apparatus provides an ultrasound image of an inspection area. An array transducer comprising a plurality of transducers for transmitting an ultrasonic signal to the inspection area and receiving an ultrasonic signal reflected from the inspection area; A composite aperture beamformer for beamforming a scanning line by controlling transmission and reception of an ultrasonic signal to the array transducer; A display unit; A controller which controls the synthesized aperture beamformer to provide an ultrasound image of the inspection area to the display unit; The control unit presets a limit position line at a position spaced from the array transducer in the inspection area in advance, and the control unit drives the composite aperture beamformer by a receiving dynamic focusing technique to the entire inspection area. After displaying the ultrasound image on the display unit, the synthesized aperture beamformer is driven by a synthetic aperture focusing technique for the remaining regions except for the region from the array transducer to the limit position line to obtain an ultrasound image of the corresponding region. And display on the ultrasound image of the display unit.

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