JP5091556B2 - Ultrasonic diagnostic apparatus and ultrasonic image generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic device for performing reception delay processing by performing geometry transformation by using a GPU. <P>SOLUTION: The ultrasonic diagnostic device includes: a transmission and reception means 003 for transmitting and receiving an ultrasonic signal via an ultrasonic probe 001 having a plurality of vibrators 002; an A/D converting means 004 for converting ultrasonic signals received from the plurality of vibrators 002 into digital data respectively; a delay means which comprises the GPU 100 and grants delay to the respective digital data; an addition means 102 for adding up respective data with delay granted; a coordinate conversion means 010 for converting data added up into data of an orthogonal coordinate system from a coordinate system when transmitted and received; and a display control means 011 for displaying data coordinate converted to a display means 012. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic image generation method that generate ultrasonic images by transmitting and receiving ultrasonic waves. More specifically, the present invention relates to a reception beamformer that performs a delay addition process on a reception signal.

  The ultrasonic diagnostic apparatus transmits a focused ultrasonic wave at a certain point by changing the transmission pulse time for each element of the array transducer in the probe. After receiving the reflection echo by the transmission pulse for each element of the array transducer and performing delay control so that all the elements are focused, the received signals from each element are added. A block that performs the delay control and the addition of the reception signal is called a reception beamformer.

  Here, a conventional receive beamformer will be described with reference to FIGS. FIG. 11 is a diagram for explaining the delay distance and delay time in each array transducer. FIG. 12 is a diagram showing the delay distance of each array transducer on an equiwave surface with an ultrasonic wave deflection angle θ = 30 ° (angle from the center of the array transducer to reflect the ultrasonic wave) and a depth of 10 mm. It is.

A description will be given of a case where a reception echo is obtained from a point P having a depth d deflected to an angle θ (hereinafter sometimes referred to as “reception focus point d”) in the array transducer 70 arranged on a straight line. The distance to the point P is the distance between the center 71 of the array transducer and the transducer 72 at a position x apart.
δ = d−d ′ + d ₀
= D-{(dsinθ-x) ² + (dcosθ) ² } ^1/2 + d ₀ (Formula 1)
d ₀ : There is a difference in bias value for preventing the delay from becoming negative.

  Therefore, with respect to the reflected echo from the transducer 72, the signal received by the transducer 72 needs to be delayed by the distance of Equation 1 in order to adjust the timing of the reflected echo at the array transducer center 71. .

When the distance of (Equation 1) is converted into time,
τ = δ / C
= (D − {(dsinθ−x) ² + (dcosθ) ² } ^1/2 + d ₀ ) / C (Formula 2)
C: Corresponds to the speed of sound.

In FIG. 12, the bias value d ₀ = 10 mm is added. The white circles in the drawing represent the positions of the respective transducers on the equiwavefront corresponding to the array transducer center 71. Here, the vibrators are arranged at every element position of 4 mm. The transducer 80 shown in FIG. 12 is located 14 mm from the center 71 of the array transducer. And based on Formula 2, the delay distance in each depth for every vibrator | oscillator is calculated | required from this figure. For example, a case where the far distance of the white circle 81 is calculated will be described. As shown in FIG. 12, the depth from the transducer 80 with respect to the point where the depth from the array transducer center 71 is d1 = 10 mm is measured as d ₂ mm. The angle is θ = 30 °, and the delay distance between the vibrator center 71 and the vibrator 80 is expressed by (Equation 1):
δ = 10 − {(10 sin 30 ° −14) ² + (10 cos 30 °) ² } ^1/2 +10
≒ 6.8
It is.

Therefore, (this value far distance is subtracted from the measured depth. That is, d ₂ −6.8 is obtained.) The transducer 80 is given the measured depth d ₂ and the calculated delay distance 6.8. Find the echo signal at.

  The above is performed for a point on the equiwavefront corresponding to a depth of 10 mm from the array transducer center 71, signals corresponding to the respective transducers are obtained, and those signals are added to obtain a signal from the array transducer center 71. A signal at a depth of 10 mm is obtained.

  The operation for obtaining the above signals is performed corresponding to each depth from the array transducer center 71, and an echo signal corresponding to each depth is obtained.

  By doing so, it is possible to generate scan line data at a certain angle (30 ° in the above description) from the array vibration center 71. The above operation is called reception beam forming.

  In the prior art, this delay and addition are performed by hardware. In the past, this hardware was realized by an analog circuit using an analog delay line. However, in recent years, the received signal of each element is A / D converted and the digital circuit performs delay and addition. At this time, since the delay accuracy is not good at a normal sampling frequency (for example, 40 MHz), the signals from all elements (vibrators) are added by upsampling several times to give a delay. After addition, downsampling to the original sampling frequency. For example, the number of sampling points is the number of white circles in FIG. 12, but the number of transducers is fixed, and is determined by the number of vertical points shown in FIG. For example, in the state of FIG. 12, the number of sampling points is 80. Then, for example, upsampling to double is to double the number of vertical points, and the sampling points in FIG. 12 are interpolated between the vertical points and below the bottom point. The total number of points is 160. The above-described delay and addition are performed on the 160 points to generate data on one scanning line.

  When the above operations are realized by hardware, the depth, that is, the reception focus point d continuously changes, and the hardware configuration becomes complicated.

  Further, in the ultrasonic image generating apparatus, after receiving beam forming, quadrature detection is performed, and data generated by receiving beam forming is converted to an in-phase component (hereinafter referred to as “I signal”) and quadrature (Quadrature−). phase) component (hereinafter referred to as “Q signal”). This converted signal is called an IQ signal. Next, decimation is performed to thin out sampling points, and envelope detection, which is a trace operation for a short time maximum value, is performed. Then, the envelope-detected data is logarithmically compressed to obtain a wide dynamic range. Further, the raster data obtained as described above is coordinate-converted into an orthogonal coordinate system. Then, the ultrasonic image generating apparatus displays the ultrasonic image on the display means based on the data obtained above.

  In the above description, the method of beam forming with the received RF (Radio Frequency) signal is explained. However, other than that, the received RF signal is orthogonally detected and converted into the baseline IQ signal, or the Hilbert transform is performed. There is also a method of performing reception beam forming after conversion to the analysis signal IQ signal.

Specifically, the received RF signal is A (t−τ) cos {ω (t−τ) + φ} (Formula 3)
A (t): envelope, ω: frequency, φ: initial phase, τ: time delay.

When (Equation 3) is quadrature detected (converted to a baseline IQ signal),
A (t−τ) e ^{j (−ωτ + φ)} (Formula 4)
It becomes. From (Equation 4), the baseline IQ signal requires a time delay of τ and a phase delay of ωτ.

Further, when (Equation 3) is converted to Hilbert transform (converted into analysis signal IQ signal),
A (t−τ) e ^{j {ω (t−τ) + φ}} (Formula 5)
It becomes. (Equation 5) requires only a time delay of τ for the analysis signal IQ signal.

  Here, in (Expression 4) and (Expression 5), the envelope A (t) can be derived simply by taking an absolute value.

  Beam forming is performed based on (Equation 4) or (Equation 5) thus obtained. Even in such a method, the hardware configuration is complicated when beamforming is performed by hardware. Even if the number of sampling points is increased, it is only possible to acquire sampling points several times the original sampling points.

  Therefore, recently, a technique for realizing reception beam forming by software (for example, see Patent Document 1) has also been proposed. In this method, the above-mentioned reception beamforming is performed by processing a program in which delay addition processing is defined by a DSP (Digital Signal Processor) or a CPU (Central Processing Unit).

JP 2003-180688 A

  However, when the above-mentioned reception beamforming is realized by software of a CPU or DSP, the processing algorithm is complicated and a long processing time is required, so that it is difficult to display an ultrasonic image almost simultaneously with the inspection. .

  This invention is made in view of such a situation, and it aims at providing the ultrasonic diagnosing device which performs a reception delay process using geometry conversion.

  It is another object of the present invention to provide an ultrasonic diagnostic imaging apparatus that allows a general-purpose GPU (Graphics Processing Unit) to process this geometry conversion.

In order to achieve the above object, the ultrasonic diagnostic apparatus according to claim 1 is a transmission / reception unit that transmits / receives an ultrasonic signal via a transducer, and an A / D conversion that converts the received ultrasonic signal into digital data. The digital data for each focus point depth corresponding to each of the ultrasonic beam having a predetermined deflection angle in the depth direction is acquired, and a plurality of polygons consisting of polygons are set for the plurality of digital data and a delay means to digital data of the plurality of by collectively performing geometry converted into a plurality of said polygons delaying and adding means for adding data to which the delay is given to the summed data And a display control unit that generates an ultrasonic image based on the display unit and displays the image on the display unit.

The ultrasonic image generation method according to claim 17 includes a transmission / reception step of transmitting / receiving an ultrasonic signal via a transducer, an A / D conversion step of converting the received ultrasonic signal into digital data, and a plurality of the digital signals A delay stage for converting data into a plurality of polygons and adding a delay by performing geometry conversion on the plurality of polygons; an addition stage for adding the digital data to which the delay is given; And a display control step of generating an ultrasonic image based on the digital data and displaying it on a display means.

According to the ultrasonic diagnostic method according to the ultrasonic diagnostic apparatus and claim 17 according to claim 1, it is possible to perform delay processing by the geometry transformation. Since geometry conversion is performed by floating point arithmetic, it is possible to improve delay accuracy in receive beamforming. In addition, since reception beam forming can be performed on data corresponding to the point to be displayed, the resolution can be improved as compared with the case of generating data corresponding to the point to be displayed by interpolation.

[First Embodiment]
Hereinafter, an ultrasonic diagnostic apparatus according to a first embodiment of the present invention will be described. FIG. 1 is a block diagram showing functions of the ultrasonic diagnostic apparatus according to this embodiment.

  The ultrasonic probe 001 is composed of N transducers 002. The vibrator 002 receives a pulse signal (pulser) from the transmission unit 003, converts it into an ultrasonic wave, and transmits the ultrasonic wave to the subject. Here, the ultrasonic wave is focused at one specific point by one transmission. Hereinafter, this point is referred to as a focus point. Further, the vibrator 002 receives the ultrasonic echo reflected by the subject, converts the received ultrasonic echo into an electrical signal, and outputs the electrical signal to the transmission / reception means 003.

  The transmission / reception means 003 responds to the distance from each transducer 002 to the focus point (hereinafter, sometimes referred to as “depth”) so that the ultrasonic waves transmitted from the transducers 002 simultaneously strike the focus point. A transmission delay circuit (not shown) for providing a delay, a pulsar (not shown) for transmitting a pulse signal, and a preamplifier (not shown) for amplifying a voltage are included. The transmission / reception means 003 gives a transmission delay to the pulse signal that drives the vibrator 002 by the built-in transmission delay circuit, and outputs the pulse signal to the ultrasonic probe 001. Further, the transmission / reception unit 003 amplifies the signal received from the ultrasonic probe 001 by a preamplifier (not shown), and then outputs the amplified signal to the A / D conversion unit 004.

  The A / D conversion unit 004 converts the signal received from the transmission / reception unit 003 into a digital signal. Then, the A / D conversion unit 004 stores the digital signal in the storage unit 005.

  The storage unit 005 is configured by a storage medium such as a memory. The storage unit 005 receives the digital data corresponding to the digital data received from the A / D conversion unit 004, the deflection angle of the ultrasonic beam when the data is acquired, the distance (depth) to the focus point, and the digital data. The position of the transducer 002 and the value of digital data (brightness in B-mode processing and power in Doppler processing) are stored. Here, as the value of the digital data, a value of data assumed to be reflected at the focus point of the transmitted ultrasonic wave is used. Further, the distance to the focus point is obtained by measuring the time taken to acquire data assumed to be the reflection.

  The three-point selection unit 111 and the target point setting unit 112 are constituted by the CPU 110.

  The three-point selection unit 111 receives data from the storage unit 005 whose scanning direction is an angle θ from the array transducer center. When this data is represented by a graph, it becomes a graph representing the digital data values of points corresponding to the coordinate system of the depth and the position of the transducer 002 as shown in FIG. Here, FIG. 2 is a graph of data arrangement before geometry conversion in the scanning direction θ. The vertical axis of the graph shown in FIG. 2 is the distance (depth) to the focus point, and the depth increases as it goes down in the figure. Also, the horizontal axis of the graph shown in FIG. 2 is the position of the transducer 002 and is represented by the distance from the array transducer center 201. In FIG. 2, the vibrator 002 is schematically represented by assuming that the vibrator 002 is configured by the vibrator 202 every 4 mm. However, the vibrator 002 is actually smaller, for example, the interval between the vibrators 002 is 0. In the case of .5 mm, every 4 mm of the vibrator 202 of the present embodiment means every eight vibrators 002. Further, in FIG. 2, the sample points are represented by white circles 203 as the points corresponding to the equiwavefront 204 at a distance of 10 mm from the array transducer center 201 and the transducers every 4 mm on the equiwavefront 204. Actually, more detailed sample points are taken. For example, if the sampling frequency of the A / D converter 004 is 40 MHz, 261 sample points are included in 10 mm.

  For example, as shown in FIG. 3, the three-point selection unit 111 selects three points such as a point 300a, a point 300b, and a point 300c. FIG. 3 is a diagram for explaining selection of three points by the three-point selection unit 111. Here, for convenience of explanation, three points are selected on the same point as the white circle 203 which is the sample point shown in FIG. 2, but the point 300a and the point 300b exist on the same equiwavefront. The point 300c may be two points, and the point 300c may be a point in the same horizontal axis direction as the point 300a or the point 300b, and the point 300c may be a point other than the points 300a and 300b. That is, the points 300a, 300b, and 300c do not have to be on the sample points in FIG. 2, and a point between the sample points may be selected. In that case, it is necessary to obtain a point to be the point 300a, 300b, or 300c by using interpolation such as bilinear interpolation from surrounding points. This bilinear interpolation is performed by the GPU 100.

  Here, a GPU (Graphics Processing Unit) is a programmable processor that can perform operations by parallel processing and performs geometry conversion that converts a shape into another shape using the operations by the parallel processing. It is a possible processor. Further, the geometry conversion function of the GPU generally indicates the following functions. For example, as shown in FIG. 13, from a rectangle formed by points 131, 132, 133, and 134 to a rectangle formed by points 135, 136, 137, and 138 that are rectangles of different shapes. To convert. FIG. 13 is a schematic diagram for explaining the geometry conversion. In order to convert this rectangle, it is only necessary to set the movement destinations of the four vertices. Actually, the triangular polygon formed by the points 131, 132, and 133 is converted into a triangular polygon formed by the points 135, 136, and 137. Further, the triangular polygon formed by the points 132, 133, and 134 is converted into a triangular polygon formed by the points 136, 137, and 138. In this case, the rectangle 330 is converted into a rectangle 331 and the circle 332 is transformed into an ellipse 333. Further, there may be a case where there is no sample point in the coordinates of the conversion source corresponding to the conversion destination, and in this case, an image after conversion is created by interpolation from several points around the conversion source. The GPU can execute bilinear interpolation using four neighboring points at high speed. Furthermore, the GPU is equipped with a large number of arithmetic circuits (circuits called vertex shaders and pixel shaders) in parallel, and can perform high-speed computation by parallel processing. Their processing is programmable. Thus, the GPU is a processor capable of high-speed processing specialized for application in the field of computer graphics. Here, the polygon refers to a conversion source area for geometry conversion. Hereinafter, a region that is a conversion source for geometry conversion may be referred to as a “polygon”.

  The three-point selection unit 111 repeats the selection of the above three points so that all sample points are included in the range surrounded by the three points created, and the ranges surrounded by the created three points do not overlap each other. Arrange as follows. For example, in the present embodiment, the minimum region surrounded by three points corresponding to the intersection of the lines shown in FIG. 4, that is, the same region as that represented by the three points of points 300a, 300b, and 300c in FIG. Cover all the graphs. FIG. 4 is a diagram for explaining the arrangement of data after geometry conversion. Here, the point 300a and the point 300b are base points, and the point 300c is a vertex. In the present embodiment, the area formed by the base point and the vertex all cover the entire graph with the same triangle.

  In this respect, the size and shape of the area covering this graph (here, “size” refers to the distance between the vibrator 002 and the distance from the base point to the apex) need not be the same shape. The graph may be covered with different areas. For example, FIG. 6 is a diagram illustrating an example in which the entire graph is covered using regions of different sizes and shapes. As shown in FIG. 6, since the distortion of the iso-wave surface 204 is large at a shallow place, a fine dot is taken to reduce the area to improve the accuracy of graphic conversion, and at a deep place (the distance from the array transducer center 201 is long). Since the distortion of the equiwave front is small, there is little deterioration in accuracy even if a large area is used with coarse points, so that a large area may be used to speed up the processing. Here, when receiving at a frequency of 5 MHz, the interval between the base points and the base points to the apexes necessary to maintain the accuracy of 1/100 of the wavelength by linear interpolation with the vibrator 002 at the end 14 mm away from the center. The interval is sufficient to be 1.2 mm when focusing at a depth of 10 mm, and 12.0 mm is sufficient when focusing to a depth of 100 mm. In this way, it is possible to increase the interval between sample points in a deep place, and by doing so, it is possible to increase the processing speed of graphic conversion.

  The target point setting unit 112 receives the three points selected by the three-point selection unit 111, the lengths of two sides sandwiching the right angle are the distances in the horizontal axis direction of the points 300a and 300b, and the points 300a and 300c. A right triangle that forms a distance is created. Here, points corresponding to the points 300a, 300b, and 300c are point 400a, point 400b, and point 400c, respectively. The point 400a, the point 400b, and the point 400c are target stores that are conversion targets. Then, as shown in FIG. 4, the sides sandwiching the right angle, that is, the sides formed by the points 400a and 400b and the sides formed by the points 300a and 300c are arranged so as to be parallel to the respective axes.

  Similarly, the target point setting unit 112 arranges target points for all three points selected by the three-point selection unit 111. At this time, the sides adjacent to the two points on the same wavefront in FIG. 3 that are adjacent on the wavefront are arranged so as to be continuous. Specifically, in FIG. 3, sides 401a formed by points 400a and 400b which are sides corresponding to points 300a and 300b, and sides corresponding to points 300b and 300d which are sides adjacent to points 300a and 300b. Each target point is set such that the side 401b formed by the points 400b and 400d is continuous as shown in FIG. By doing so, the equal wavefront 201 in FIG. 3 is converted into an equal wavefront 402 represented by a straight line in FIG.

  The GPU 100 is a processor capable of performing graphic processing by hardware. The GPU 100 includes a geometry conversion unit 101 and an addition unit 102 as shown in FIG. The GPU 100 corresponds to the “delay unit” in the present invention, and the ultrasonic diagnostic apparatus according to the present embodiment includes the “adder unit” in the present invention in the GPU 100.

  The geometry conversion unit 101 has the three points selected by the three-point selection unit 111, the three points set by the target point setting unit 112, which are points included in the region formed by the points 300a, 300b, and 300c (sample points). , The point 400a, the point 400b, and the point 400c are converted into points on the region formed. This conversion is performed so that the point 300a is converted to the point 400a, the point 300b is converted to the point 400b, and the point 300c is converted to the point 400c. Further, in the entire graph, the point 300a is converted to the point 400a, the point 300s to the point 400s, the point 300t to the point 400t, and the point 300u to the point 400u, respectively. Further, in this embodiment, the geometry conversion is performed in the state where the graph is covered with the same triangle, but for example, the size and shape of the region covering the graph are changed by changing the interval of the sample points as shown in FIG. Even in this case, by performing geometry conversion on each region, it is possible to convert so that the equiwavefront becomes a straight line as shown in FIG. 7 and adjacent sides are continuous on the equiwavefront. FIG. 7 is an example of an arrangement of data after geometry conversion when the entire graph is covered using regions of different sizes and shapes. 6, the point 600a in FIG. 6 corresponds to the point 700a, the point 600s to the point 700s, the point 600t to the point 700t, and the point 600u to the point 700u, respectively. Converted. This geometry conversion corresponds to “adding delay” in the present invention.

Here, when there is no sample point in the coordinates of the conversion source corresponding to the conversion destination, the geometry conversion unit 101 creates the conversion source point from a plurality of sample points around the conversion source by interpolation such as bilinear interpolation. Then, a necessary conversion destination point is generated by converting the point. By this interpolation, it is possible to improve the accuracy of arranging the data on the equiwavefront in a straight line (hereinafter referred to as “wavefront alignment”) as compared with the interpolation of sampling points used in the conventional delay processing. Become. All processing of the GPU 100 including these interpolation calculations is performed by floating point calculations. In other words, it can be said that the wavefront fitting accuracy is only the accuracy of floating point arithmetic. Specifically, in the conventional delay processing, as shown in FIG. 8A, interpolation points indicated by small white circles are generated between original sampling points indicated by black circles in order to increase the accuracy of wavefront alignment. As a result, the output data is generated from the points, and the wave front is adjusted. Here, FIG. 8A is a diagram for explaining conventional interpolation of sampling points. In this method, a delay system that exceeds the original sampling point and interpolation point cannot be obtained. On the other hand, in the case of sampling point interpolation using the floating point in the present invention, for example, when performing a floating point calculation up to 3 digits after the decimal point, the wavefront is adjusted with an accuracy that uses a point that is 10 ³ times the sample point. It can be carried out. For example, as shown in FIG. 8B, the input data (interpolation point of the sampling point) corresponding to the required output data is interpolated using a floating point up to 3 digits after the decimal point. As shown, an arbitrary interpolation point can be generated with an accuracy of three digits after the decimal point. As a result, the ultrasonic diagnostic apparatus according to the present embodiment can have a delay accuracy of floating-point arithmetic with 3 digits after the decimal point. FIG. 8B is a diagram for explaining sampling point interpolation using a floating point. Here, the sampling point interpolation is a process similar to the “upsampling” described in the background art.

  As the interpolation of the conversion source point, bilinear interpolation may be insufficient in accuracy in terms of frequency characteristics. In that case, higher-order interpolation can be performed by creating a shader program that is a program for deforming the shape. Furthermore, since the GPU 100 has a large number of arithmetic circuits (128 or more in the higher-order chip) in parallel for performing shader processing, the above-described shader program can be calculated at high speed by parallel processing. These processes in the GPU 100 are programmable.

  The addition processing unit 102 adds the data (brightness and power) of the points on the equiwavefront 402 converted into a straight line in the direction of the vibrator 002. In this embodiment, this addition is simply performed. However, the addition may be performed in combination with a variable aperture or a process such as apodization as shown in FIG. FIG. 5 is a diagram for explaining apodization. FIG. 5A is a graph of sampling points to which a delay due to geometry conversion is given. The vertical axis represents the depth, and the horizontal axis represents the distance from the array transducer center 201 of each transducer 002. 5 (B-1), (B-2), and (B-3) are graphs of functions used for weighting in the corresponding equiwavefront, the vertical axis is the weighting value, and the horizontal axis is This is the distance of each transducer 002 from the array transducer center 201. The variable aperture is a process for reducing the aperture used at a short distance and increasing the aperture at a deep portion. Apodization is a process of changing the weight according to the channel (CH) of each vibrator 002. That is, in the equiwave surface 500a where the depth of the focus point is shallow, the transmission / reception of ultrasonic waves in the transducer 002 distant from the array transducer center 201 increases the deflection angle, resulting in a large data distortion. Therefore, it is preferable to use a lot of data near the center 201 of the array transducer. Therefore, a function for strongly weighting data near the array transducer center 201 shown in FIG. 5B-1 is used for the equiwave surface 500a. As the focus point becomes deeper, the deflection angle becomes gentler, so that the distortion of data at a remote location can be suppressed. Therefore, the function shown in FIG. (B-2) is used for the equiwave surface 500b, and data at a location away from the array transducer center 201 as shown in FIG. (B-3) is also used for the equiwave surface 500c. Use a function that This function is expressed by a Gaussian function, for example. In this case, the adding means 102 adds the data weighted by the apodization as described above.

  Here, in this embodiment, the addition processing means 102 is arranged in the GPU 100 and the addition processing is performed by the GPU 100. However, since the load of the addition processing for convolving the data after geometry conversion between the transducers is not large, Processing may not be performed by the GPU 100. In this case, the addition processing means 102 is arranged in the CPU 110, and the CPU 110 performs addition processing on the data after geometry conversion input from the GPU 100.

  The quadrature detection means 006 performs quadrature detection on the RF data corresponding to the deflection angle of the angle θ obtained by beam forming from the GPU 100 and converts it into an IQ signal.

  The decimation means 007 performs downsampling called decimation by thinning out a certain number from the sampling points converted into IQ signals. This requires a very large number of sample points to determine the delay because the delay system is determined by the sample interval, but since the delay processing has already been completed here, an ultrasonic image is actually generated. Decimation is performed to extract the required amount of sample points. For example, the decimation means 007 reduces the sampling points of 2000 points to 500 points.

  The envelope detection means 008 performs envelope detection on the IQ signal thinned out by decimation.

  The logarithmic compression unit 009 applies a number of compressions to the obtained envelope in order to increase the dynamic range. Thereby, for example, 16-bit data is compressed to 8 bits.

  The coordinate conversion unit 010 converts data received from the logarithmic compression unit 009 represented as raster data on the coordinate system at the time of transmission / reception into data represented on the orthogonal coordinate system.

  The display control unit 011 causes the display unit 012 to display the data converted into the data on the orthogonal coordinate system by the coordinate conversion unit 010. Here, the display unit 012 is a monitor or the like.

  Next, the flow of generating an ultrasonic image by the ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to FIG. FIG. 9 is a diagram showing a flowchart of ultrasonic image creation by the ultrasonic diagnostic apparatus according to the present embodiment.

  Step S001: The transmission / reception means 003 transmits / receives an ultrasonic wave to / from the subject via the transducer 002 of the ultrasonic probe 001 and acquires a reception signal.

  Step S002: The A / D conversion means 004 converts the received signal received from the transmission means 003 into digital data and stores it in the storage means 005.

  Step S003: The three-point selection unit 111 acquires data for each depth of the focus point in an ultrasonic beam having a predetermined deflection angle, obtains an equal wavefront, and obtains two points on the equal wavefront from the storage unit 005, and One point other than the two points having the same position from the center of the array transducer as any one of the two points is selected.

  Step S004: The target setting means 112 forms a target point that is the target of conversion of the three points selected by the three-point selecting means 111, forms a right triangle whose target points are parallel to both axes, and the equiwave front becomes a straight line. The adjacent sides of the sides formed by the two points on the equiwavefront are set to be continuous.

  Step S005: The geometry converting unit 101 maps and converts the region formed by the three points so as to correspond to the right triangle formed by the target point so that the three points selected by the three-point selecting unit 111 move to the target point. .

  Step S006: The adding means 102 adds the converted data on the equiwavefront received from the geometry converting means 101.

  Step S007: The quadrature detection means 006 performs quadrature detection on the added data received from the GPU 100 and converts it into an IQ signal.

  Step S008: The decimation means 007 decimates the IQ signal received from the quadrature detection means 006.

  Step S009: The envelope detection unit 008 performs envelope detection of the IQ signal received from the decimation unit 007 and obtains an envelope.

  Step S010: The logarithmic compression unit 009 performs logarithmic compression on the envelope received from the envelope detection unit 008.

  Step S011: The coordinate conversion unit 010 converts the data received from the logarithmic compression unit 009 from the rough data on the coordinate system at the time of transmission / reception to the data on the orthogonal coordinate system.

  Step S012: The display control unit 011 causes the display unit 012 to display data on the orthogonal coordinate system received from the coordinate conversion unit 010.

  The ultrasonic diagnostic apparatus according to the present embodiment is configured by a program that defines the operation as described above.

  As described above, the ultrasonic diagnostic apparatus according to the present embodiment can obtain the delay of the received signal using geometry conversion. As a result, it is possible to improve the accuracy of matching of the equiwavefronts up to the accuracy of floating point arithmetic. Further, by causing the GPU to perform geometry conversion, an operation that gives a delay by hardware can be performed. As a result, the processing speed can be increased as compared with the case where the CPU executes the program and calculates the delay. Furthermore, by using a general-purpose GPU, it is not necessary to develop dedicated hardware for performing delay processing, and it becomes easy to manufacture an ultrasonic diagnostic apparatus that performs delay processing. This makes it possible to reduce the manufacturing cost of the ultrasonic diagnostic apparatus.

  In this embodiment, the three-point selection unit 111 and the target point selection unit 112 are configured as a part of the function of the CPU 110. However, this is configured as a part of the function of the GPU 100, and the GPU 100 can select three points. A target point may be set.

  Furthermore, in the present embodiment, only the received beamforming such as delay processing by geometry transformation and addition processing is performed by the GPU 100, but the orthogonal detection means 006, decimation means 007, envelope detection means 008, logarithmic compression means 009, and coordinates All or a part of the conversion unit 010 may be configured as a part of the function of the GPU 100, and the GPU 100 may be caused to execute all or a part of the processes from the orthogonal detection to the coordinate conversion after the reception beam forming.

  Further, in this embodiment, the geometry conversion is performed as it is with the RF signal to give a delay, but this is performed by direct detection to convert to a baseline IQ signal, or Hilbert conversion to convert to an analysis signal IQ signal. Later, geometry conversion may be performed to give a delay.

  Furthermore, in the present embodiment, three points are selected for geometry conversion, and the area formed by the three points is converted into a right triangle. However, the area to be converted is not limited to the area formed by the three points. It is also possible to perform beam forming by selecting a point above the point and performing geometry conversion. Specifically, when geometric transformation is performed on an area formed by three or more selected points, the equiwavefront becomes a straight line and a plurality of sample points arranged on the equiwavefront are transformed. Are converted so that they are arranged in the same order, and beam forming can be performed if the converted region includes all sample points.

  Further, in this embodiment, in order to perform more accurate beam forming, an equiwavefront is obtained and geometry conversion is performed every time beam forming is performed. However, the equiwavefront is uniquely determined by the deflection angle, and the number of rasters forming the equiwavefront is rarely changed during scanning. Therefore, it is also possible to store polygons for each raster in advance in a storage unit (not shown) in the GPU 100 and perform geometry conversion on the stored polygons. In this case, it is not necessary to calculate the equal wavefront and set the polygon every time, so that it is possible to reduce the load in the beam forming process.

[Second Embodiment]
An ultrasonic diagnostic apparatus according to the second embodiment of the present invention will be described below. The ultrasonic diagnostic apparatus according to the present embodiment has a configuration in which corresponding point extraction means 013 is added to the ultrasonic diagnostic apparatus according to the first embodiment. A dotted line arrow in FIG. 1 represents a data flow in the present embodiment.

  First, the principle of processing performed by the ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to FIGS. 14A is a graph of data arrangement based on the received ultrasonic echoes before geometry conversion, FIG. 14B is a graph after polygon setting, and FIG. 14C is a display means. The figure of the ultrasonic tomogram displayed on the. FIG. 14D illustrates the arrangement of data after performing geometry conversion. FIG. 14E shows the data after the addition processing is performed on the data that has undergone the geometry conversion. The processes performed by the ultrasonic diagnostic apparatus according to the present embodiment are shown in FIGS. 14A to 14C. However, for easy understanding, the flow of the processes performed by the ultrasonic diagnostic apparatus according to the first embodiment is described. Figures 14 (D) and 14 (E) are also shown. In the ultrasonic diagnostic apparatus according to the first embodiment, polygon setting is performed on the data arranged in the graph shown in FIG. 14A as shown in FIG. All the data is converted as shown in FIG. 14D by performing geometry conversion on some of them. Then, the data after geometry conversion is added to all the channels to generate data after beam forming as shown in FIG. Then, coordinate conversion is performed to convert the generated data after beam forming from scan coordinates to orthogonal coordinates, and an ultrasonic tomographic image as shown in FIG. And when converting into this orthogonal coordinate, since there is not necessarily the data after the beam forming of the position corresponding to the display pixel of the display means 012, the data is created by interpolation. In contrast, the ultrasonic diagnostic apparatus according to the present embodiment is configured to create post-beamforming data corresponding to the position of the pixel to be displayed. For example, the display pixel 142 in FIG. Let the pixel position of the display pixel 142 be (x, y). The position of the sample point corresponding to the pixel position (x, y) can be uniquely determined from the center of the array transducer by the deflection angle θ and the depth d. Then, based on the deflection angle θ and the depth d from the center of the array transducer corresponding to the pixel position (x, y), a necessary beam forming pattern is determined, and a polygon including the sample is determined. This determined polygon is an area 141 shown in FIG. Then, geometry conversion is performed on the region 141 determined based on θ and d. As described above, this geometry conversion is to convert one shape into another shape using computation by parallel processing as schematically shown in FIG. At this time, it is necessary to calculate in advance information on which transmission beam the received signal is used for. It is necessary to give not only time delay but also phase delay to the signal after quadrature detection. The phase delay can be realized by complex multiplication. Since the phase delay value can be determined by θ, d, and the channel position, the phase delay value corresponding to the pixel position (x, y) is calculated in advance based on θ, d, and the channel position. This value and the value of each channel after geometry conversion (after time delay) are complex multiplied. By adding the results for all channels, a complex signal after beam forming corresponding to the pixel 142 having the coordinates of the pixel position (x, y) is obtained. When the complex signal is obtained, envelope detection is performed by taking the amplitude, logarithmic compression is performed, and the result is displayed on the display unit 012. Hereinafter, the configuration of the ultrasonic diagnostic apparatus according to the present embodiment will be described.

  The ultrasonic probe 001, the transmission / reception unit 003, and the A / D conversion unit configured by a plurality of transducers 002 have the same configuration as that of the first embodiment, and the operation up to transmission / reception of ultrasonic waves by the transmission / reception unit 003 This is the same as in the first embodiment.

  The quadrature detection unit 006 performs quadrature detection on the data of the RF signal received from the transmission / reception unit 003 and converts it into a baseline IQ signal. In the present embodiment, the quadrature detection means 006 converts the signal into a baseline IQ signal, but this may be converted into an analysis signal IQ signal, which is an analysis signal, by performing a Hilbert transform.

  The A / D conversion unit 004 converts the analog signal received from the direct detection unit 006 into digital data. Further, the A / D conversion unit 004 stores the baseline IQ signal converted into digital data in the storage unit 005.

  The corresponding point extraction unit 013 stores the orthogonal coordinate system used by the coordinate conversion unit 010, and extracts display pixels on which the ultrasonic image in the orthogonal coordinate system is displayed. Then, the corresponding point extracting unit 013 obtains an envelope that is raster data corresponding to the extracted display pixel. Further, the corresponding point extraction unit 013 extracts a baseline IQ signal having the envelope from the obtained envelope. The extracted baseline IQ signal is correspondence data corresponding to the extracted display pixel on the orthogonal coordinate system. Here, since the envelope is obtained by taking the absolute value of the baseline IQ signal, the original baseline IQ signal can be obtained from the envelope. This is also possible with the analytic signal IQ signal subjected to Hilbert transform. Thereby, the data on the graph shown in FIG. 14B corresponding to the display pixels on the image shown in FIG. 14C, that is, the above-described corresponding data is obtained. For example, the area 141 shown in FIG. 14B is obtained for the display pixel 142 in FIG.

  The three-point selecting unit 111 extracts three points from the corresponding data received from the corresponding point extracting unit 013 as in the first embodiment.

  The target point setting unit 112 sets the target point that is the conversion target of the three points selected by the three-point selection unit 111 in the corresponding data, as in the first embodiment.

  The geometry conversion unit 101 receives the selected three points in the corresponding data and the target points from the three-point selection unit 111 and the target point setting unit 112, respectively, so that the selected three points move to the target points. The region formed by the three selected points in the corresponding data is mapped and converted into the region formed by the target point.

  As described above, the data corresponding to the display pixel of the display unit 012 shown in FIG. 14C is directly generated from the data on the graph shown in FIG. 14B by extracting the three points, setting the target point, and converting the geometry. Is done. For example, the data value of the display pixel 142 in FIG. 14C is directly obtained from only the data in the region 141 in FIG. This eliminates the steps of geometric conversion of all sample points as shown in FIG. 14D and creation of raster data as shown in FIG. 14E, which are required in the first embodiment. Can do.

  The adding unit 102 adds the data given the delay by the geometry converting unit 101 in the direction of the vibrator 002.

  The envelope detection unit 008 obtains an envelope of the added data received from the addition unit 102.

  The logarithmic compression unit 009 performs logarithmic compression on the envelope received from the envelope detection unit 008.

  The display control unit 011 displays an ultrasonic image on the display unit 012 based on the data received from the logarithmic compression unit 009.

  In this embodiment, since the ultrasonic image data corresponding to the display pixel extracted by the corresponding point extracting unit 013 is generated, the data generated on the display pixel extracted by the corresponding point extracting unit 013 is used. They need only be arranged, and there is no need to convert them into data represented on the orthogonal coordinate system by the coordinate conversion means 010.

  Next, a flow of ultrasonic image creation in the ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to FIG. FIG. 10 is a flowchart of ultrasonic image creation in the ultrasonic diagnostic apparatus according to this embodiment.

  Step S101: The transmission / reception means 003 transmits / receives an ultrasonic wave to / from the subject via the transducer 002 of the ultrasonic probe 001 and acquires a reception signal.

  Step S102: The quadrature detection unit 006 performs quadrature detection on the data received from the transmission / reception unit 003 and converts it into a baseline IQ signal.

  Step S103: The A / D conversion means 004 converts the baseline IQ signal received from the direct detection means 006 into digital data and stores it in the storage means 005.

  Step S104: The corresponding point extraction unit 013 obtains an envelope corresponding to the extracted display pixel, and obtains correspondence data that is a baseline IQ signal having the envelope.

  Step S105: The three-point selection unit 111 obtains data for each depth of the focus point in the ultrasonic beam having a predetermined deflection angle from the corresponding data, obtains an equiwave surface, and obtains the equiwave surface from the storage unit 005. 2 points and one point other than the two points having the same position from the center of the array transducer as any one of the two points.

  Step S106: The target setting unit 112 forms a target point that is the target of conversion of the three points selected by the three-point selecting unit 111, forms a right triangle with the target point parallel to both axes, and the equiwave front is a straight line. The adjacent sides of the sides formed by the two points on the equiwavefront are set to be continuous.

  Step S107: The geometry conversion unit 101 maps and converts the region formed by the three points so as to correspond to the right triangle formed by the target point so that the three points selected by the three-point selection unit 111 move to the target point. .

  Step S108: The adding means 102 adds the converted data on the equiwavefront received from the geometry converting means 101.

  Step S109: The envelope detection unit 008 performs envelope detection on the data received from the addition unit 102 to obtain an envelope.

  Step S110: The logarithmic compression unit 009 applies logarithmic compression to the envelope received from the envelope detection unit 008.

  Step S111: The display control unit 011 causes the display unit 012 to display the data on the orthogonal coordinate system received from the coordinate conversion unit 010.

  As described above, only data corresponding to display pixels extracted by performing delay processing, addition processing, envelope detection, logarithmic compression, and coordinate conversion on the corresponding data corresponding to the display pixels extracted on the orthogonal coordinate system. Can be requested. As a result, only data necessary for displaying the ultrasonic image is processed, so that unnecessary data need not be processed, and the processing load can be reduced. Further, the resolution can be improved as compared with a method of calculating data necessary for displaying on a display pixel by interpolating the obtained data as in a conventional ultrasonic diagnostic apparatus.

  In the present embodiment, three points are selected for geometry conversion, and the area formed by the three points is converted into a right triangle. However, the area to be converted is not limited to the area formed by the three points. It is also possible to perform beam forming by selecting a point above the point and performing geometry conversion. Specifically, when geometric transformation is performed on an area formed by three or more selected points, the equiwavefront becomes a straight line and a plurality of sample points arranged on the equiwavefront are transformed. Can be formed if they are converted so that they are arranged in the same order.

  Further, in this embodiment, in order to perform more accurate beam forming, an equiwavefront is obtained and geometry conversion is performed every time beam forming is performed. However, it is also possible to store a polygon for each raster in advance in a storage unit (not shown) in the GPU 100 and perform geometry conversion on the stored polygon. In this case, it is not necessary to calculate the equal wavefront and set the polygon every time, so that it is possible to reduce the load in the beam forming process.

The block diagram showing the function of the ultrasonic diagnostic equipment concerning the present invention Graph of data arrangement before geometry conversion in scan direction θ The figure for demonstrating selection of 3 points | pieces by a 3 point | piece selection means Diagram for explaining data layout after geometry conversion (A) Graphs of sampling points given delays due to geometry conversion (B-1), (B-2), (B-3) Graphs of functions used for weighting in corresponding equal wavefronts Illustration of an example of covering the entire graph using areas of different sizes and shapes An example of the layout of data after geometry conversion when the entire graph is covered using areas of different sizes and shapes (A) Diagram for explaining conventional interpolation of sampling points (B) Diagram for explaining interpolation of sampling points using floating point The figure showing the flowchart of ultrasonic image creation by the ultrasonic diagnostic apparatus which concerns on this embodiment FIG. 6 is a flowchart of ultrasonic image creation in the ultrasonic diagnostic apparatus according to the present embodiment. The figure for demonstrating the delay distance and delay time in each array vibrator The figure which showed the delay distance of each array vibrator | oscillator in the equal wave front for every 10 mm in the deflection angle (theta) = 30 degree of an ultrasonic beam. Schematic diagram for explaining geometry conversion (A) Graph of data arrangement based on received ultrasonic echo before geometry conversion, (B) Graph after polygon setting for sample points, (C) Ultra displayed on display means The figure of an acoustic tomogram, (D) The figure which shows arrangement | positioning of the data after performing geometry conversion, (E) The figure which represents the data after performing addition processing to the data which performed geometry conversion

Explanation of symbols

001 Ultrasonic probe 002 Transducer 003 Transmission / reception means 004 A / D conversion means 005 Storage means 006 Orthogonal detection means 007 Decimation means 008 Envelope detection means 009 Logarithmic compression means 010 Coordinate conversion means 011 Display control means 012 Display means 013 Corresponding point extraction Means 100 GPU (delay means)
101 Geometry conversion means 102 Addition means 110 CPU
111 Three-point selection means 112 Target point setting means

Claims (22)

Transmitting and receiving means for transmitting and receiving an ultrasonic signal via a vibrator;
A / D conversion means for converting the received ultrasonic signal into digital data;
Obtaining the digital data for each depth of the focus point corresponding to each ultrasonic beam having a predetermined deflection angle in the depth direction, setting a plurality of polygons consisting of polygons for the plurality of digital data ,
A delay unit that delays the plurality of digital data by collectively performing geometry conversion on the plurality of polygons ;
Adding means for adding the data given the delay;
An ultrasonic diagnostic apparatus comprising: a display control unit that generates an ultrasonic image based on the added data and displays the ultrasonic image on a display unit. The ultrasonic diagnostic apparatus according to claim 1 , wherein a GPU is used as the delay unit. The ultrasonic diagnostic apparatus according to claim 2 , wherein the GPU is a programmable processor that performs geometry conversion for converting a shape into another shape using an operation based on parallel processing. Coordinate conversion means for converting the added data from a coordinate system at the time of transmission / reception to data of an orthogonal coordinate system,
The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic image is generated based on data of the orthogonal coordinate system. The vertices forming the polygon include points calculated by bilinear interpolation with the previous GPU,
The ultrasonic diagnostic apparatus according to any one of claims 2 to 4, wherein the ultrasonic diagnostic apparatus is characterized in that The interval between the vertices of the previous period that forms the previous period polygon is roughened in a deep area compared to a shallow area.
The ultrasonic diagnostic apparatus according to claim 4 or claim 5, wherein The position of the first vertex that forms the first polygon is moved to the position of the target point determined by the depth of the focus point, thereby performing geometry conversion.
The ultrasonic diagnostic apparatus according to any one of claims 4 to 6, wherein The delay means is
Receiving the digital data for each depth of the focus point corresponding to each ultrasonic beam having a predetermined deflection angle in the depth direction, the distance in the depth direction to the focus point is the vertical axis, and the position of the transducer is An equal wavefront represented by an ultrasonic signal received by each transducer from a focus point of the same depth, which is expressed at a position including a delay time, is obtained in the coordinate system on the horizontal axis, and the same on the coordinate system. A plurality of points on the equiwavefront and at least one point on the equiwavefront with different depths are selected, and the equiwavefront on the coordinate system is formed without overlapping regions formed by the selected points. Point selection means for repeating the selection so that all the points representing are included in any of the regions;
And a geometric conversion means for converting a region formed by the selected points so that the equiwavefront is a straight line, and adjacent points on the same equiwavefront are also adjacent on the straight line. The ultrasonic diagnostic apparatus according to any one of claims 4 to 7 . The delay means is
The digital data is acquired for each depth of the focus point corresponding to each ultrasonic beam having a predetermined deflection angle in the depth direction, and the ultrasonic signal received by each transducer corresponding to the focus point of the same depth An equal wavefront that is a plane is obtained, and two points on the equal wavefront and one point that is not on the equal wavefront corresponding to one of the two points are selected in total, and the digital data up to the focus point is selected. When represented by a point on the delay coordinate system represented by the distance and the position of the transducer, the area formed by the three points does not overlap with each other, and the digital data is all in one of the areas. Three-point selection means for repeating the selection to be included;
In the coordinate system, the two points and the one point are right-angled triangles, the equiwave front is a straight line, and the straight line formed by the two points is continuous with the straight line formed by the two adjacent points. Target point setting means for setting a target point as a target of the conversion of the three points;
Geometric conversion means for converting each of the equiwavefronts into a straight line by geometrically converting the region so that the three points coincide with the corresponding target points;
The ultrasonic diagnostic apparatus according to claim 4, further comprising: The delay means is
Receiving the digital data for each depth of the focus point corresponding to each ultrasonic beam having a predetermined deflection angle in the depth direction, the distance in the depth direction to the focus point is the vertical axis, and the position of the transducer is An equal wavefront represented by an ultrasonic signal received by each transducer from a focus point of the same depth, which is expressed at a position including a delay time, is obtained in the coordinate system on the horizontal axis, and the same on the coordinate system. A plurality of points on the equiwavefront and at least one point on the equiwavefront with different depths are selected, and the equiwavefront on the coordinate system is formed without overlapping regions formed by the selected points. Selecting points so that all points representing are included in any of the regions, and storing the selected points;
An area formed by the selected points such that the equiwavefront is a straight line with respect to the stored selected points and the adjacent points on the same equiwavefront are also adjacent on the straight line. The ultrasonic diagnostic apparatus according to claim 4, further comprising a geometry conversion unit that converts The delay means is
The digital data is acquired for each depth of the focus point corresponding to each ultrasonic beam having a predetermined deflection angle in the depth direction, and the ultrasonic signal received by each transducer corresponding to the focus point of the same depth An equal wavefront that is a plane is obtained, and two points on the equal wavefront and one point that is not on the equal wavefront corresponding to one of the two points are selected in total, and the digital data up to the focus point is selected. When represented by a point on the delay coordinate system represented by the distance and the position of the transducer, the area formed by the three points does not overlap with each other, and the digital data is all in one of the areas. Select the points to be included, store the selected points in advance, and further, the two points and the one point will be a right triangle, the equiwave front will be a straight line, and the two points will be formed The two points adjacent to each other are So as to be continuous with the straight line formed, and stores set a target point which is a target of the three-point transform on the coordinate system,
Each of the iso-wave fronts is straightened by geometrically transforming the region so that the three points at the stored selected point coincide with the corresponding stored target point. The ultrasonic diagnostic apparatus according to any one of claims 4 to 7, further comprising a geometry conversion means for conversion. Further comprising correspondence data extraction means for obtaining correspondence data that is the digital data corresponding to the points on the orthogonal coordinate system;
The delay means gives the delay to the corresponding data;
The adding means adds the corresponding data given a delay,
Wherein the display control unit ultrasonic diagnostic apparatus according to any one of claims 4 to 7, characterized in that for displaying the corresponding data is added to the point of the display of said display means. The ultrasonic diagnostic apparatus according to claim 12 , wherein the points on the orthogonal coordinate system correspond to pixel units of the display unit. The corresponding delay for data, and an ultrasonic diagnostic apparatus according to the process of the addition of the corresponding data to which the delay is given in claim 12 or claim 13, characterized in that to process at GPU. Further comprising quadrature detection means for quadrature detection of the received ultrasonic signal and converting it to a baseband signal,
The ultrasonic diagnostic apparatus according to any one of claims 4 to 10 , wherein the A / D conversion unit converts the baseband signal into digital data. Further comprising a Hilbert transforming means for transforming the received ultrasonic signal into a Hilbert transform,
The ultrasonic diagnostic apparatus according to any one of claims 4 to 10 , wherein the A / D conversion unit converts the Hilbert-transformed signal into digital data. A transmission and reception stage for transmitting and receiving an ultrasonic signal via a transducer;
An A / D conversion stage for converting the received ultrasonic signal into digital data;
Converting a plurality of said digital data into a plurality of polygons comprised of a polygon,
A delay stage that gives a delay by performing geometric transformation on the plurality of polygons ;
An adding step of adding the digital data given the delay;
A display control step of generating an ultrasonic image based on the added digital data and displaying the ultrasonic image on a display means. Coordinate conversion means for converting the added data from a coordinate system at the time of transmission / reception to data of an orthogonal coordinate system,
The ultrasonic image generating method according to claim 17, wherein the ultrasonic image is generated based on data of the orthogonal coordinate system. The vertices forming the polygon include points calculated by bilinear interpolation with the GPU,
The ultrasonic image generation method according to claim 18. The interval between the vertices of the previous period that forms the previous period polygon is roughened in a deep area compared to a shallow area.
The ultrasonic image generation method according to claim 18 or claim 19, wherein The position of the first vertex that forms the first polygon is moved to the position of the target point determined by the depth of the focus point, thereby performing geometry conversion.
21. The ultrasonic image generating method according to claim 18, wherein the ultrasonic image generating method is any one of the above. A correspondence data extraction step for obtaining correspondence data that is digital data corresponding to the points on the orthogonal coordinate system;
The delay stage gives the delay to the corresponding data;
The adding step adds the corresponding data given a delay,
The ultrasonic image generation method according to any one of claims 18 to 21, wherein the display control step displays the added correspondence data on the display point of the display means.

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