JP3154271B2 - Acquisition and display method of waveform of ultrasonic survey imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for acquiring and displaying a waveform of an ultrasonic exploration imaging apparatus, and more particularly to a method of accurately capturing the waveform of an ultrasonic wave reflected from a subject, including positive and negative peak values. The present invention relates to a method for acquiring and displaying a waveform of an ultrasonic survey imaging device that can be displayed.

[0002]

2. Description of the Related Art In an ultrasonic exploration imaging apparatus, an ultrasonic wave is emitted from an acoustic lens of a probe to a subject, and an echo of the ultrasonic wave which is reflected and returned by hitting the subject is transmitted through the acoustic lens. Make it incident. The incident ultrasonic echo is converted into an electric signal and input to the signal processing circuit. The electric signal representing the waveform of the ultrasonic echo input to the signal processing circuit unit is preferably acquired such that the waveform shape of the ultrasonic echo is accurately maintained, and stored in the memory. The data stored in the memory is read from the memory as necessary and displayed on a display. Accurately maintaining and acquiring and storing the waveform shape of the ultrasonic echo is important because the waveform shape itself often contains information on the subject. The acquisition of the waveform of the ultrasonic echo is performed by converting the voltage signal state in the analog format into data in the digital format by sampling.

As a method of storing a waveform signal of an ultrasonic echo, first, a high-speed A / D converter is used to convert an analog signal at a high speed, as represented by a digital storage oscilloscope, for example. There is a method of sampling and storing. FIG. 5 shows a conceptual diagram of sampling.
FIG. 5A shows an original waveform 101, which is a voltage signal representing a waveform of an ultrasonic echo. FIG. 5B shows an arrangement state of data obtained by sampling, and data obtained by sampling is indicated by a black point 102. When these black spots 102 are connected by broken lines 103, the obtained overall shape becomes a waveform similar to the original waveform 101. The sampling pitch is constant. This method includes an equivalent sampling method that achieves a fine sampling pitch with higher accuracy than the resolution accuracy of the A / D converter by utilizing the repeatability of the ultrasonic waveform.

As another method for acquiring a waveform signal of an ultrasonic echo, there is a method for acquiring A-scope data disclosed in Japanese Patent Application Laid-Open No. 2-140661, for example. In this method, the probe is one-dimensionally scanned, the position of a gate (a certain time range) is sequentially changed in accordance with this scanning, and the height of the ultrasonic echo at each gate position is used as data. It is configured to capture. At the time of display, on the two-dimensional display screen, one axis is a probe position and the other axis is a gate position, and the height of the ultrasonic echo is displayed in a shade of an image or a pseudo color.

[0005]

In the above first method,
In order to acquire the original waveform 101 with discrete values, if the sampling pitch is not sufficiently small compared to the wavelength of the original waveform 101, the plus (+) or minus (-) peak value of the original waveform 101 is reduced. I can't catch it enough. That is, when the sampling time does not coincide with the generation time of the peak of the original waveform, the peak value cannot be obtained. One example will be described with reference to FIG.
FIG. 6 shows an example in which the sampling is performed at the sampling frequency fs and the sampling pitch ts with respect to the original waveform 201 of the half sine wave of the ultrasonic wave having the frequency f (wavelength λ). The worst state where the peak P1 of the waveform comes at the point is shown. In this case, the error e1, that is, the difference between the true peak value K1 and the sampling value becomes maximum, and is given by the following (Equation 1).

[0006]

E1 = 1-cos (180 ° × f / fs)

As described above, according to the first method, the peak value of the ultrasonic wave having the frequency f may not be accurately detected, and a large error may occur. On the other hand, in an ultrasonic exploration imaging apparatus, it is important to accurately capture the peak value of an ultrasonic echo in order to obtain the acoustic characteristics of a subject as a reflection source. In addition, when displaying a waveform as a monitor of a focusing operation when using a focusing probe, it is difficult to use the waveform unless a peak value is always displayed at each sampling.

In the case where the first method is used, the sampling frequency fs is about 22 times or more the frequency of the ultrasonic wave in order to keep the error e1 given by the above equation (Equation 1) within, for example, 1%. Must. Therefore, in an ultrasonic exploration imaging apparatus, usually, 1 to 100 MHz
Since ultrasonic waves having a frequency of the order of magnitude are used, sampling at a very high frequency of 2.2 GHz is required for the sampling frequency fs.

Even if the maximum sampling rate satisfies the above condition, sampling is not always performed at that sampling rate. The reason is that if the time span used for display becomes long, a large capacity of a memory for temporarily storing sampling data is required. For example, when the water distance is about 30 mm, the time from when the transmission wave is emitted to when the surface echo is received is about 40 μs. In this time span, in order to sample at a sampling frequency of 2.2 GHz and store and display the obtained data,
A memory capacity of 88000 words is required.

In order to manufacture a digital storage oscilloscope satisfying the above-mentioned specifications, very high-level circuit technology is required, and the manufacturing cost of the device is increased.
There is a problem that the apparatus becomes expensive.

In the above second method, if the maximum value in the gate is set so as to be captured, the gate is set regardless of the frequency of the ultrasonic wave within the range of the analog circuit constituting the device. During this time, the peak value of the original waveform of the ultrasonic echo can be captured. However, when the time span to be displayed is long, a gap may occur on the time axis between the gate corresponding to one scanning section and the gate corresponding to the next scanning section, and the peak value may not be captured. is there. In order to avoid such a situation, it is required that an operator manually and appropriately set the width of the gate so that the peak value is not missed. Further, in the second method, since only a + peak value can be captured for one gate due to the characteristics of the circuit, there is a problem that the difference (absolute amplitude) between the + peak value and the −peak value cannot be known. Furthermore, when the phase inversion occurs in the ultrasonic echo due to the acoustic characteristics of the subject, there is a problem that the true reflection intensity cannot be known.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and when extracting the waveform of an ultrasonic echo from a subject by sampling, regardless of the frequency, sampling pitch, and sampling position of the ultrasonic wave, An object of the present invention is to provide a method of acquiring and displaying an ultrasonic exploration image apparatus which can acquire a peak value and an absolute amplitude, and does not require high technology in circuit configuration, and can be manufactured at low cost. .

[0013]

A first aspect of the present invention (corresponding to claim 1) is to provide a method for acquiring and displaying a waveform of an ultrasonic exploration imaging apparatus, in which Periodically emits ultrasonic waves, enters the reflected wave from the subject, sets the gate, extracts the waveform portion in the gate from the reflected wave waveform, holds the peak value of the waveform portion, and converts the peak value to a digital value. And storing the digital value of the peak value and the position of the gate corresponding to the peak value. Further, as a characteristic step, the width of the gate is set to a value equal to or larger than the sampling pitch determined by the time span and the number of sampling points, The gates are set by synchronizing with each of the repetition pulses for firing and shifting the gate position by the sampling pitch sequentially for each of the repetition pulses. Thus removed part of the reflected wave of the waveform, holds the part of the waveform +/- peak value, and configured to store the position of the gate and the corresponding +/- peak value of the sampling points min.

In the first aspect of the present invention, a gate having a gate width equal to or larger than the sampling pitch is formed, and the gate is shifted and set by the sampling pitch at each sampling time, and adjacent gates preferably have overlapping portions. At the same time, the waveform portion of the ultrasonic echo included in the gate is extracted, and both the positive peak value and the negative peak value or both of them and 0 are extracted and held in the waveform portion. I made it. By setting such a gate position, a waveform portion including a positive peak or a negative peak in the ultrasonic echo waveform can be taken out without fail, so that a failure to capture the waveform peak does not occur. Also, since a + peak value (equivalent value) and / or a -peak value (equivalent value) can be acquired and held from the waveform portion included in the gate,
Absolute amplitude can be obtained.

According to a second aspect of the present invention (corresponding to claim 2), in the method of acquiring and displaying a waveform of an ultrasonic survey imaging apparatus according to the first aspect of the present invention, preferably, the gate corresponding to the number of sampling points is set in the method according to the first aspect. At the same time, a gate corresponding to each sampling point is prepared by shifting the gate position by the sampling pitch in advance.

According to a third aspect of the present invention (corresponding to claim 3), the method for acquiring and displaying a waveform of an ultrasonic exploration imaging apparatus according to the first aspect of the present invention is the method according to the first aspect, wherein Are prepared at the same time, a group of a plurality of gates is treated as a set, and each of the plurality of gates is set by sequentially shifting the gate position by the sampling pitch at the corresponding sampling time in synchronization with the repetitive pulse. It is characterized by the following.

According to a fourth aspect of the present invention (corresponding to claim 4), a method for acquiring and displaying a waveform of an ultrasonic survey imaging apparatus according to the first aspect of the present invention is preferably such that the stored +/-
-The peak value is plotted vertically on the time coordinate axis associated with each gate, and the waveform of the reflected wave is displayed.

[0018]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a signal processing section of an ultrasonic survey imaging apparatus in which a waveform acquisition / display method according to the present invention is implemented, and an apparatus configuration section related thereto. The probe (ultrasonic probe) 11 is attached to the scanning mechanism 12. Scanning mechanism 1
Reference numeral 2 includes an XYZ moving mechanism, and has a function of moving the probe 11 three-dimensionally in each of three orthogonal axes (X, Y, Z). The probe 11 scans the observation region of the subject 13 by the scanning mechanism 12. The scanning mechanism 12 is controlled by a scanning control device 14, and further the scanning control device 14
Receives a command for control from the processing device 15.

The probe 11 is electrically associated with the ultrasonic flaw detector 16. The ultrasonic flaw detector 16 includes at least a pulser / receiver 17 and a detector (detection circuit) 18. The ultrasonic flaw detector 16 transmits a pulse signal to the probe 11 at a predetermined measurement cycle based on the pulsar portion of the pulsar / receiver 17. The probe 11 generates an ultrasonic wave based on the pulse signal given from the ultrasonic flaw detector 16 and emits the ultrasonic wave to the subject 13. On the other hand, the probe 11 receives an ultrasonic echo generated by reflection on the subject 13 and generates an echo signal corresponding to the pulse signal.
Output to the ultrasonic flaw detector 16. The subject 13 is installed in a water tank provided near the scanning mechanism 12. The ultrasonic flaw detector 16 receives an echo signal corresponding to the pulse signal output to the probe 11 based on a receiver portion of the pulser / receiver 17. The received echo signal is amplified, and the detector 18 at the next stage obtains a required peak value (that is, a positive (+) peak value and / or a negative (-) peak value and / or 0) by a method described later. And sends it to the A / D converter 19. A /
The D conversion device 19 converts the obtained peak value from an analog value to a digital value in, for example, 8 bits and 256 stages, and a microprocessor (MPU) 20 of the processing device 15.
Is transmitted to the bus 21 as input data that can be processed.

The detector 18 includes a gate circuit 18a.
And a + peak hold circuit 18b and a -peak hold circuit 18c. The gate circuit 18a is connected to the processing device 1
5 has a function of generating a certain time range set based on the command from 5, that is, a gate set temporally, and cutting out only the portion of the ultrasonic waveform corresponding to the range of this gate. + Peak hold circuit 18b is a gate circuit 18
+ peak value or + of the waveform portion cut out by a
The value corresponding to the peak value is basically held. If there is no + peak value in the cut-out waveform portion, 0 is held. The peak hold circuit 18c basically holds a value corresponding to the -peak value or -peak value of the waveform portion cut out by the gate circuit 18a. 0 if no peak value exists in the cut out waveform portion
Is held. The detailed operation of each of the gate circuit 18a, the + peak hold circuit 18b, and the -peak hold circuit 18c will be described later in the description of the operation.

The bus 21 has, in addition to the microprocessor 20, a keyboard (not shown), a memory 2 having an area for storing various programs and an area for storing data.
2. The image memory 23 and the operation panel 24 are connected. The image memory 23 is connected to a display 25 provided outside the processing device 15 and supplies the image data stored therein to the display 25 to perform a display operation. The operation panel 24 is an interface through which a measurer inputs parameters necessary for a scanning operation such as a visual field, a sampling pitch, and a feed pitch.

In the memory 22, a gate position / gate width calculation program 22a, a waveform display program 22b
Is stored, and a waveform storage area 22c is further provided.
The contents related to the operation by the gate position / gate width calculation program 22a and the waveform display program 22b will be described in the following operation description.

Next, a method of acquiring and displaying the waveform of an ultrasonic echo from the subject 13 in the ultrasonic exploration imaging apparatus having the above configuration will be described.

First, the sampling pitch ts is determined. Usually, the measurer operates the operation panel 24 to set the range of the waveform to be acquired and displayed, that is, the time span, and the number of points (sampling points or display points) from which the waveform data is to be acquired. Microprocessor 2
0 calculates the sampling pitch ts by equally dividing the time span by the number of acquisition points using the data of the time span and the number of acquisition points input on the operation panel 24 (see the following equation (1)). Microprocessor 20
Further obtains a value obtained by adding α determined by the accuracy of the gate circuit 18a to the sampling pitch ts (see the following equation (2)), and determines this value as the gate width t _G. A gate having this gate width is set in the gate circuit 18a of the detector 18. The value of α is usually about 0 to Ts / 2. The above calculation of the gate width is executed by the gate position / gate width calculation program 22a in the memory 22.

[0026]

## EQU1 ## Sampling pitch (ts) = time span / number of acquisition points (1) Gate width (t _G ) = ts + α (2)

An electric pulse is repeatedly transmitted from the pulsar / receiver 17 to the probe 11 at a constant period in accordance with a normal measuring operation. The timing at which an electrical pulse is output from the pulser / receiver 17 is given by the microprocessor 20. The timing at which the waveform value is sampled from the waveform of the ultrasonic echo returned from the subject (sampling time) is determined by the timing at which the electric pulse is repeatedly transmitted. The probe 11
When an electric pulse is supplied, the vibrating element emits an ultrasonic wave. When the ultrasonic wave strikes the subject 13 and is reflected and returns to the probe 11, the probe 11 converts the ultrasonic echo into an electric signal, and converts the ultrasonic echo into an electric signal.
Send to 7. When the pulsar / receiver 17 receives the electric signal of the ultrasonic echo sent from the probe 11, the pulsar / receiver 17 amplifies the electric signal and sends it to the detector 18. The waveform of the electric signal is the same as the waveform of the ultrasonic echo.

The detector 18 to which the electric signal sent from the pulsar / receiver 17 is inputted is synchronized with the above-mentioned timing at which the above-mentioned electric pulse is repeatedly transmitted, and the gate set by the above-mentioned gate circuit 18a (the gate width is t) _G ), the + peak hold circuit 18b and the -peak hold circuit 18c extract and hold the + peak value and the -peak value of the waveform of the electric signal included in the gate. At this time, when a + peak value (or a value corresponding to the + peak value) and a -peak value (or a value corresponding to the -peak value) exist in the waveform in the gate, both of them are taken out, and only one of them is taken out. If not, the one and 0 are extracted. The retained + peak value and −peak value or either one and 0 (hereinafter referred to as “+/− peak value”) are converted to digital values by the A / D converter 19 and then sent to the processor 15. Sent,
It is stored in the waveform storage area 22c of the memory 22. When storing a +/- peak value or the like in the waveform storage area 22c,
-The peak value and the position of the gate at that time are stored as a set.

In the detector 18, the pulsar / receiver 1
7, the gate circuit 18a sets the gate in synchronization with the timing at which the electric pulse is repeatedly transmitted, and sets the gate to +/- peak from the electric signal waveform within the range of the gate. Retrieves and holds a value. At this time, each time the gate set by the gate circuit 18a of the detector 18 is set, the gate position is shifted by the sampling pitch ts.

The above-described waveform acquisition operation will be described in more detail with reference to FIGS. In FIG. 2, the above α is set to 0 for convenience of explanation.

Extraction of +/- peak value based on FIG.
The method of holding will be described in principle. In FIG. 2, reference numeral 41 denotes a signal waveform corresponding to the electric signal. However, for convenience of explanation, it is shown by a half sine wave. Gates 42 a to 42 whose gate width is the sampling pitch (ts) in the time axis direction
d (that is, α = 0) is set. Since the gate is shifted by the sampling width ts when the gate width is ts, no overlap occurs between the gates. Waveform 41
For the gate 42a, the left end value 51b (corresponding to the -peak value) and the right end value 51a (corresponding to the + peak value), and the gate 42b has 0 (52b:-peak value does not exist) and the right end value 52a (+ peak value). ), The left end value 53a (corresponding to the + peak value) and 0 (53b:-peak value does not exist) in the gate 42c, and the left end value 54a (corresponding to the + peak value) and the right end value 54b (- (Corresponding to the peak value) are respectively taken out and held. According to the extraction and holding of such a waveform, for example, the + peak value K at the gate 42b
2 is substantially retained. Similarly, the peak value can be retained. In this manner, the +/- peak value can be extracted from each gate, and therefore, the peak value of the waveform can be obtained regardless of the frequency of the ultrasonic wave and the sampling position. In addition, each gate 42a-4
In 2d, the positive peak value and the negative peak value, or any one and zero are obtained, so that the absolute amplitude of the waveform can be obtained. In the display position of the waveform value data obtained by sampling, for example, the center position of each gate is used as a representative value of the sampling position.

FIG. 3 shows the gate width t _G (= ts +
The step of taking out and holding the waveform value while sequentially shifting the gate 43 having α) at the time of taking out and holding the waveform value is illustrated. In FIG. 3, reference numeral 44 denotes the original waveform of the electric signal, which corresponds to the waveform of the ultrasonic echo. As the time elapses along the time axis with respect to the original waveform 44, the gate 43, that is, for example, the gate (1) to the gate (5) are set while being sequentially temporally shifted. Each of the gates (1) to (5) is set in synchronization with transmission of an electric pulse. In the setting of the gate in this case, the gate is shifted by the sampling width ts at a gate width of t _G , so that an overlapping portion is formed between adjacent gates. In each of such gates (1) to (5), the +/- peak value 45, that is, for example, +/- peak (1) to ++ is obtained by the above-described waveform data acquisition method described with reference to FIG. // peak (5) is retrieved and retained. The above acquisition of the waveform value is the same in the subsequent acquisition and holding of the waveform value in the other gates.

The setting of the gate position of the gate 43 is as follows.
This is executed by the gate position / program width calculation program 22a stored in the memory 22.

As described above, the +/- peak values at each gate extracted by the above-described method of extracting and holding the +/- peak values in the detector 18 are all converted into digital values as described above. Waveform storage area 22
c is stored together with the corresponding gate position.

Next, a waveform can be displayed on the display 25 using the +/- peak value at each gate stored in the waveform storage area 22c and based on the waveform display program 22b stored in the memory 22. And image memory 2
3 stores the position of each gate and the corresponding +/- peak value. In the storage of data based on the waveform display program 22b in the image memory 22, +/- peak values are plotted by regarding the intermediate position of each gate as a sampling position and the horizontal or vertical direction of the image memory 22 as a time axis. The content of the data stored in the image memory 22 is
It is displayed on the display 25 as it is. FIG. 4 shows an example of the +/- peak display drawn by the +/- peak value 45 obtained as described above. FIG.
In the example of +/- peak display in the above, if a waveform line is drawn with reference to the description of FIG. 2, a waveform in which the + peak value and the -peak value are accurately captured can be displayed.

The above-described waveform acquisition / display method uses the configuration of the gate circuit and the A / D conversion circuit of the electric circuit portion in the conventional ultrasonic survey imaging apparatus, or uses a relatively small change or This can be achieved only by adding, and a high-precision peak value can be obtained with an inexpensive configuration, and a waveform display with high peak-value accuracy can be performed.

In the above waveform acquisition / display method, when the sampling pitch ts becomes relatively large with respect to the frequency f of the ultrasonic wave, the actual peak position on the time axis and the display position are shifted. There is a problem that it occurs. However, the above method can accurately capture the peak value representing the acoustic characteristic of the reflection source, and can be used as a monitor while adjusting the water distance during focusing.
It becomes an important technology as an ultrasonic exploration imaging device and enhances usability.

In the above-described method of extracting and holding the waveform, when the detector 18 holds the peak value while shifting the gate position by the sampling pitch every time in synchronization with the repetition of the electric pulse, in other words, the repetition of the ultrasonic emission Has been described in which one gate is sequentially shifted. As another method, the same number of gates as the number of sampling points can be simultaneously generated in a circuit. That is, it is possible to simultaneously prepare gates corresponding to the number of sampling points, and set the gates corresponding to each sampling point by shifting the gate position by the sampling pitch in advance. Further, as still another method, a plurality of gates whose number is smaller than the number of sampling points can be simultaneously generated in a circuit, and the gates can be sequentially combined with each other. That is, a plurality of gates with a number smaller than the number of sampling points are prepared at the same time,
A group of a plurality of gates can be treated as a set, and each of the plurality of gates can be set by sequentially shifting the gate position by the sampling pitch at the corresponding sampling time in synchronization with the repetitive pulse.

[0039]

As is apparent from the above description, according to the present invention, the gate is determined based on the sampling pitch determined from the time span and the number of data acquisition points and the value α to be added, and the gate is preferably determined. Since it is set so as to be shifted while forming an overlapping portion, the sampling time is determined in this gate, and the +/- peak value can be taken out and held in each gate, so that the ultrasonic frequency, sampling pitch, The + peak value and the -peak value of the ultrasonic echo waveform and the absolute amplitude can be acquired and displayed without depending on the sampling position and the like. Therefore, a peak value representing the acoustic characteristic of the reflection source can be accurately captured, and a highly accurate image display can be performed. Also, by simply creating and setting a specific gate and holding the peak value in that gate, an ultrasonic echo waveform including a highly accurate peak value can be acquired. In addition, an ultra-high-speed A / D conversion circuit or the like is not required, and a waveform acquisition / display method can be realized with an inexpensive device configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of an ultrasonic survey imaging apparatus according to the present invention.

FIG. 2 is a waveform explanatory diagram for explaining in principle the method of sampling the +/− peak values employed in the waveform acquisition / display method according to the present invention.

FIG. 3 is a diagram specifically showing an example of sampling of +/− peak values in the waveform acquisition / display method according to the present invention.

FIG. 4 shows + obtained by the waveform acquisition / display method according to the present invention.
FIG. 9 is a diagram showing a display of a peak value.

FIG. 5 is a diagram showing an example of waveform acquisition by a conventional digital storage oscilloscope.

FIG. 6 is a waveform explanatory diagram for explaining peak value sampling by a conventional digital storage oscilloscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Probe 12 Scanning mechanism 13 Subject 15 Processing device 16 Ultrasonic flaw detector 17 Pulser / receiver 18 Detector 43 Gate 45 +/- peak value

Continuation of the front page (56) References JP-A-2-140661 (JP, A) JP-A 1-248053 (JP, A) JP-A 4-160359 (JP, A) JP-A 4-127705 (JP, A) , A) (58) Fields studied (Int. Cl. ⁷ , DB name) G01N 29/00-29/28

Claims (4)

(57) [Claims] An ultrasonic wave is periodically emitted to a subject, a reflected wave from the subject is incident thereon, a gate is set, and a waveform portion in the gate is extracted from a waveform of the reflected wave. A waveform acquisition / display method for an ultrasonic sounding image apparatus that retains a peak value of a waveform portion, converts the peak value into a digital value, and stores a position of a gate corresponding to the digital value of the peak value. The width is set to a value equal to or greater than the sampling pitch determined by the time span and the number of sampling points, and the gate position is shifted by the sampling pitch sequentially for each repetition pulse in synchronization with each of the repetition pulses for emitting the ultrasonic waves. Setting a part of the waveform of the reflected wave by each of the gates, and calculating a +/- peak value from the part of the waveform. Lifting, and stores the position of the gate and the corresponding +/- peak value of the sampling points worth, ultrasonic inspection waveform acquisition and display method of the image and wherein the. 2. A gate corresponding to the number of sampling points is prepared at the same time, and the gate corresponding to each sampling point is set by previously shifting the gate position by the sampling pitch. Acquisition and display method for ultrasonic survey imaging equipment. 3. A plurality of gates having a number smaller than the number of sampling points are prepared at the same time, a group of the plurality of gates is treated as a set, and each of the plurality of gates is synchronized with the repetition pulse to perform a corresponding sampling. At the time,
2. The method according to claim 1, wherein the gate position is sequentially shifted and set by the sampling pitch. 4. The reflected wave waveform is displayed by plotting the stored +/− peak values vertically on a time coordinate axis associated with each of the gates. Acquisition of the waveform of the ultrasonic survey imaging device described
Display method.