JPS62192146A - Ultrasonic medium measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to an apparatus for measuring a medium using ultrasonic waves, and particularly for measuring signal waveforms and spectral shapes caused by the superposition of signals in transmitted waves and reflected waves in a heterogeneous medium such as a cow's body. The present invention relates to a method for reducing distortion by nonlinear averaging including a fluctuation signal generated by adding delayed fluctuation to a signal.

[Prior art]

When ultrasonic waves are transmitted or reflected through a heterogeneous medium such as a beam, distortion occurs due to the inhomogeneity.During transmission, multiple refraction occurs due to local sound speed differences, which results in multiple refraction. Even if the same ultrasonic beam is received, the difference in the sound speed of the path partially passed through is integrated.
An advanced portion and a delayed portion coexist on the beam wavefront.

These phenomena Vi [Multi-path
) effect or phase cancellation effect, and in the case of continuous waves, the amplitude and phase of the transmitted received signal vary greatly depending on the path, even in the same inhomogeneous medium.

In the case of pulses, the time waveform, spectrum amplitude, and phase of the received signal similarly vary greatly.

In reflection, a pulse is sent to a specific region of interest (RO
It is reflected at I) and received again, but on this round-trip path, it is subject to varying distortions exactly the same as when it is transmitted. In addition, the scatterers that cause reflection within the region of interest are usually arranged randomly and at intervals shorter than the pulse length, so the echo pulses reflected from each scatterer overlap with each other.
Mutual interference causes waveform and spectrum fluctuation distortion of the received signal to be greater than in the case of transmission.

This phenomenon is idealized when the envelope of the high-frequency echo signal in the rlA mode image of a medical echo tomography device is viewed as a time waveform, and the measurement system can be regarded as a one-dimensional model, and the attenuation can be ignored, although it is heterogeneous. In this case, the amplitude should originally be constant regardless of the depth, but it exhibits irregular periodic fluctuations due to the distortion caused by the interference caused by the M tatami. Furthermore, when viewed as a B-mode image, the current pattern (SPECKLE pattern) is
appears. Hereinafter, the above-mentioned phenomenon in the time domain will be referred to as a "speckle phenomenon."

When the reflected pulse waveform from a single reflector is frequency-analyzed by Fourier transform, it generally has a frequency spectrum shape that approximates a smooth Gaussian distribution, but the reflected pulses from multiple reflectors are superimposed on each other. The spectral shape of an echo signal with a scallop has irregular irregularities, similar to the cross section of a scallop shell, and this distortion phenomenon in the frequency domain is called the scallop phenomenon. do.

Speckle extremely degrades the quality of B-mode images, making it impossible to discover local lesions that are equal to or smaller than speckle t1''i.In addition, scallop affects frequency characteristic parameters such as attenuation and reflection scattering. This causes an extremely large error in the determination of .

First, the cause of phase cancellation is that in a phase-sensitive transducer such as PZT, which faithfully follows the phase (positive and negative polarity) of the sound pressure as a receiving transducer, the leading wavefront part and the delayed wavefront part are the same on the PZT. It has been proposed to use phase Φ insensitive transducers such as CdS which are sensitive to power rather than backpressure because of the canceling effect of producing signals of opposite polarity. In this case, since positive power is output regardless of whether the polarity is positive or negative, the cancellation phenomenon does not appear in the sum. However, it is not put into practical use because of its low sensitivity, slow time response, and lack of reception directivity due to power sensitivity.

A further improvement has been proposed in which the receiving transducer aperture is mosaiced into a large number of small-area elements, each element's output is squared, all converted to positive power outputs, and then summed. . Compared to CdS, this is expected to improve sensitivity and time response, and effectively reduce phase cancellation in the time domain, but it is not practical due to the lack of receiving directivity and the complexity of the circuit. Not yet. In the frequency domain, the outputs of each element are all individually Fourier transformed,
A method was proposed in which the scallop caused by phase cancellation is completely reduced by converting the power spectra into power spectra and then adding the respective power spectra. Although this is effective, it suffers from the same omnidirectionality and complexity as the time domain case.

Furthermore, the above-mentioned phase cancellation measures have the following essential problems and are completely ineffective. That is, the wavefront reaching the receiving transducer aperture is at the transducer plane (X-
This is effective against wavefront distortion that locally leads and lags on the Y plane), but even if the element dimensions are so small that they can be considered to have the same phase, the received signal are already superimposed in the pulse sending/receiving direction (z-axis direction), so distortion due to weight cannot be removed. That is, although superimposition in the lateral direction (X-Y plane) can be removed, superimposition in the depth direction (two axes) cannot be removed. If the depth direction superimposed strain is removed, the lateral direction superimposed strain will be solved at the same time, so from now on we will consider the depth direction superimposed strain as a representative.

In order to remove superimposed distortion (speckles or scallops), methods are being pursued to perform theoretically accurate and deterministic methods for one received signal using signal processing. Because the attenuation coefficient has a frequency characteristic in the medium and the phase characteristic caused by it is unknown, it is difficult to determine the pulse waveform until it reaches a certain depth, is reflected there, and then is transmitted back in the opposite direction. It is not possible to detect changes and is not active in either the time domain or the frequency domain.

Next, for the echo signal from Δ2 (spatial window) near a specific depth 2 on a specific scanning line, the speckles and scallops are moving averaged in the time domain and frequency domain, or the least square error is fitted to the true value model. Attempts were made to reduce the This takes advantage of the fact that when heterogeneity is completely random, the average value approaches the true value. However, the time average adaptation range cannot be made long due to attenuation and the local structure of the living body, and the frequency average adaptation range is also limited by the frequency bandwidth that can be realized by the ultrasonic transducer. It has been found that there is a limit to distortion removal with moving average and least square error fitting.For example, in a living body, the attenuation coefficient α is
When determining the proportionality coefficient (attenuation coefficient slope) β from the echo signal in a proportional medium (α = βf), the error due to the above-mentioned scallop distortion is clarified. This error is β
When trying to use this to identify biological lesions, the β
It has been found that the difference is similar to or larger than the difference in

Therefore, we further set mutually independent measurement unit regions of length △2, that is, spatial windows, on as many mutually independent scanning lines as possible within a spatial region that is considered to be the same lesion site (tissue property). Then, the moving average value or the least squares error fitting value of f'i in the above-mentioned time domain or frequency domain of the echo signal from each, or the total fat conduction amount from them, and the large number of spatial windows set spatially. (measurement unit area) is averaged. When measuring β in the liver using currently available ultrasound transducers, the thickness of the area required for spatial averaging is approximately 2 cm if the shape is a square.
rIL is reported to be minimal. 44 [Problems to be Solved by the Invention] Such spatial averaging significantly reduces the spatial resolution of measured values (for example, induced quantities such as β). For example, if the diameter of liver cancer exceeds about 1 clt, there is a very high probability that it has already metastasized to other parts of the body. It would be totally unsuitable for the purpose. In addition, averaging scanning over a large number of scanning lines requires a significant amount of time for measurement and processing, and requires storage of multiple scanning signals, impairing real-time performance and increasing the size of the hardware. .

The present invention eliminates these drawbacks, provides a method for reducing errors caused by superimposed distortion, increasing spatial resolution, and improving real-time performance.

[Means to solve the problem]

The purpose of the present invention is to apply delayed fluctuation to the received signal output of the transducer element (single or plural) constituting an ultrasonic probe, to generate a plurality of processing fluctuation outputs, and to generate a nonlinear signal in this and normal signals. Ultrasonic medium measuring device 1- which reduces distortion caused by superimposition of ultrasonic signals by performing averaging (addition) after processing and has high accuracy, high spatial resolution, and excellent real-time performance. It is on offer.

[Effect]

In addition to the delay normally used for deflection and focusing of ultrasound beams, there is no intentional fluctuation in the received signal of an element of an ultrasound probe from one or more elements or their composite signal. A plurality of swing outputs for processing are created in addition to the normal output signal by applying a delay, and the processing that is the same as processing all of the normal output signals and that includes at least one nonlinear process is applied to each swing signal. By averaging (adding W-) the processed output including the normal output signal, distortion and errors caused by superimposition of the ultrasonic signal are reduced.

〔Example〕

The present invention will be explained below with reference to Examples.

To simplify the explanation, the zero-transmission type will be explained as the gold side of a reflection-type medium measuring device that transmits pulses and receives them with the same probe.The superimposed distortion is lower in the case of the zero-transmission type, and the exact same concept can be applied. Although this is omitted from the example because the distortion can be reduced by this, it does not deviate from the application of the present invention.

The explanation will proceed from simple configuration examples to more and more complex configuration examples.

First, an example of the configuration of the first embodiment is shown in FIG. In FIG. 1, an element XI l which forms an aperture during reception in the device
Deflection connected to xz l...Xj...Xn, respectively.

Switches and delay elements SD for focusing and aperture control.

SDt,...SDj...SDn, and delay fluctuation element ψ
Only the nonlinear averaging (NLA) circuit after h is shown in full, including a transmitting section, an amplifying section, a scan open control section, and a storage section 1 display control section.

Other parts necessary for functioning as a single device, such as a light display, are omitted.

Aperture constituent element groups X r , X t...X in FIG.
When n is collectively expressed as <Xj>, <Xj> represents n elements used to scan one scanning line among all elements in a linear self-array. In a seven aided array, all elements are typically used as apertures for all scan lines. The display example is a linear array that is always (dynamically) electronically focused on the scanning line direction (Z-axis) perpendicular to the aperture plane.

At a short distance (distance where 2 is close to the aperture size), the formed ultrasonic beam diameter cannot be smaller than the aperture size, so a switch is used to separate the elements around the aperture and make the aperture smaller. The aperture is also dynamically varied depending on the depth. If the ultrasonic pulse transmitted at time 0 has a sound speed of C, then
Depth zK is reached after 2IG time, where the pulses that were just reflected in the opposite direction travel in the opposite direction and are again received respectively at the transducer <Xj> after z/C time. Therefore, among the received echo signals, what is received at time t after transmission is a reflected signal at depth z=Ct/2.

Therefore, all quantities that are functions of depth 2) can be read as functions of time, and as mentioned above, controlling the focusing and aperture according to the depth is also called dynamic itt control. be.

Therefore, in order to focus and receive at depth 2, each element Xj
Point □c on the axis with digit t (x=Xj, z=o) and depth 2
= o , z = z ) distance (Xj2+z'')2'
If a delay element (including the aperture control switch at the same time) <SDj>t- is provided to correct the difference in propagation time depending on j so that they are all the same, then the point (X=O, z=z
) are all emphatically added in the same phase at the addition point (Σ) of the output of <SDj> in FIG. 1, resulting in high receiving sensitivity. The phases of signals from points other than the point (x=0, z=z) are not all the same at the addition point, but are
There is a delay component, which cancels each other out and reduces reception sensitivity.
This is the principle of focusing using a delay element. The same applies to deflection. Usually, the value of each delay of <SDj> is dynamically controlled according to the progress of the pulse, ie, according to the depth, so as to temporally satisfy the focusing (deflection) condition.

The above is the purpose and operation of the conventional delay element <SDj>. This composite signal is used as a composite signal (ORD, 5IG) for B-mode video, Doppler analysis, etc., and further for biological tissue characterization.

In the present invention, the addition output is provided with p branches, each branch is provided with a swinging delay element <Dzi>', and each delay time τ is
Zl is configured to take different pm values.

In □□□, p types of delay times are provided separately and in parallel, but in the actual configuration, they are arranged in order from the smallest τgift to the longest one, and each adjacent delay time is It is more compact and inexpensive to connect delay elements having different delay times in series and take out the output from each intermediate connection point. The illustrated example is a parallel connection for simplicity of illustration and explanation. The same applies to examples below 0. Even when a pulse is transmitted, the reflector continuously Because of the directional distribution, the received echo signal exhibits a continuous series of waveforms in which the echo pulses from each reflector are superimposed on each other. Therefore, when the normal signal (ORD, 5IG) receives an echo corresponding to depth 2, each signal subjected to delayed oscillation @ is at a position shifted by Δzi before and after 2 on the Z axis. Respond to signals. In other words, such oscillation is a serial delay oscillation, and the physical 1c is equivalent to oscillating the measurement unit area, ie, the spatial window, in the depth direction. In other words, this is equivalent to spatial averaging in the depth direction.

Generally, the time width (time window) on the echo signal corresponding to the measurement unit area (spatial window) is required to be several times the pulse length, which is approximately 10
It is said to be about μ3. The corresponding measurement unit area (spatial window) is approximately 7.5n when the sound speed is 1.5iIi/llS.
becomes. Two oscillation outputs with a difference in oscillation delay time that is sufficiently smaller than 10 μsK become approximate signals with large cross-correlation because their respective spatial windows overlap for the most part, and there is no point in averaging them. On the other hand, two oscillation outputs whose oscillation delay time difference is close to or larger than 10μB become independent from each other,
Although this increases the averaging effect, it also reduces the spatial resolution. Therefore, from the target spatial resolution, the spatial window length, and the independence of data, there is a limit to the maximum value of the swing delay τi, and it is desirable that each is arithmetic, and the value of p is optimal. You can see that it has value. It is often sufficient for p to be 16 or less.
explain. In this example, the output of each element Xj passes through a switch delay circuit SDj and is then branched into q parts. For the i-th (i=1°2,...q) branch among each of the q branches, the swing delay amount τrij (j=1, 2...n
) Delay circuit Drlj (j=1.2°..., n)
are provided, and the outputs of each Drij from 1=1 to j=n are added and combined to obtain the oscillation output Ol. 11 equal j=
Determine the delay swing times from 1 to n and the set of circuits τ, 1j〉
Expressed as In this way, a swing output <01> is obtained for 1=1 to q. The total (1+q) signals of the normal signals (ORD, 5IG) and these q swing outputs are NLA.
is nonlinearly averaged to obtain an output O with reduced distortion due to superimposition.

In this embodiment, delay fluctuation is performed in parallel for each element, so it is called parallel delay fluctuation.

We describe the physical correspondence of parallel delay fluctuations. Consider an arbitrary, ie, first, fluctuation delay set τrij >. This winter Motoko is <
SDj>, reception is focused on point Q (x=0.z:=2) on two axes. Therefore, the focus is blurred near the point (0, z) by τ, 1j. In other words, the spatial range of the blur is Crr1j/
2, that is, physically the normal signal is at the convergence point (0, z)
, whereas the fluctuation signal receives information in the surrounding range Cτr4j/2 with different spatial weighting patterns. As in the previous example, the maximum value of rij (more precisely, the difference between the maximum and minimum values in τrtj) is limited by the index value of the spatial resolution.

Suppose that an arbitrary set of oscillation delay times τri
If a certain law is established between each element τ and ijO of j〉, when a swing delay is included in the delay for normal signal formation, the signal is received at a point (ΔXi, Z+Δzi) near the point (0, z). It can be made to focus. The reception focal points corresponding to the set of i = 1 to qOq τrij > are distributed at a mutual distance equal to y without overlapping each other in the spatial resolution around the point (0, z). It is desirable to design in a similar manner to minimize the cross-correlation of the oscillating output and increase the overall average effect. Of course, from the relationship between spatial resolution and cross-correlation, there is an optimal value for q, as in the previous example, and 16 or less is sufficient.

Fig. 3 shows an example in which series rocking and parallel rocking are combined. In this case, the element group <Xj> is divided into four groups a, b, c, and d, and each group is a PDW similar to the PDW in FIG.
s , P DWt , . . 4 respectively by PDW4
The seeds are subjected to parallel oscillations, and the output of each oscillation is further expressed as S in Figure 1.
This figure shows an example in which four kinds of series swings are applied by an SDW similar to a DW. Although not shown, it is also possible to take any one of the rocking outputs of each of the four groups and perform the four additions 1γ.

When moving in the conventional scanning line t-X direction and taking a spatial average, the received signal of each element is different for each scanning line, but
Since the fluctuation averaging is performed for a specific scanning line at once, the reception (M signal) of each element has a specific shape and does not change with fluctuation.For this reason, spatial averaging due to fluctuation and conventional spatial averaging are will be different and will not lead to the same result. Therefore,
The swinging average and the conventional spatial average can be used synergistically, and the number of element regions of the conventional spatial average can be reduced and the spatial resolution can be increased. In addition, since a swinging average is performed by signal processing for multiple scans, real-time performance is excellent.

Furthermore, it is possible to dynamically change the swing delay amount according to depth 2, that is, according to the time after pulse transmission, and all 2
It is also possible to keep the oscillation space, that is, the spatial resolution, within a certain range in the measurement range of , or to keep the oscillation focal point during focused parallel oscillation parallel to the scanning line at a constant distance for changes in 2. .

That is, if the swing delay amount τrij is kept constant, the displacement ΔX from the Z-axis becomes large where 2 is large, resulting in a decrease in spatial resolution. In order to prevent this, it is preferable to change τrij t- according to Z as described above.

Next, FIG. 4 shows a typical embodiment of the above-mentioned nonlinear averaging (NLA). In FIG. 4, the prisoner signal and the swing signal are treated equally, and the illustration is made assuming that there are mai type input signals.

FIG. 4(a) is an example in the frequency domain, in which a process of converting a spectrum into a power spectrum is used as a nonlinear process.

G in the figure is a time gate, and as mentioned above, it has a time length of NIO/zs, and a type such as Hamming or Hanning is used. FFT is a Fourier transform circuit, and S (f) is a circuit for converting into a power 〇 spectrum, which squares the magnitude of each Fourier-transformed frequency to obtain a power φ spectrum. Σ is an addition (averaging) circuit, which adds (averages) m power m-spectrums for each same frequency component to obtain the average value Φ spectrum 5(f)t-0 focused parallel fluctuation. So, the number of delay elements is 1, 2, 4,
In the worst case, where the received signal of each element has exactly the same waveform, that is, each element has a mutual phase rjA'c of 100, the waveform is a random scatterer with a Gaussian envelope. The logarithmic power spectrum (dB
) is shown in the fifth factor. The horizontal axis shows the number of elements, the length of one measurement window is 256 points, and the delay swing range is ±64 points, within which the case of equidistant swing is (a), and the case of random swing is (a).
b) The decrease due to an increase in the number of elements (average number) of each 0 is for a single waveform obtained by chance,
In general, it is not intended to compare the quality of (a) and (b).Originally, (a) and (b) are statistically compared to many waveforms.
(b) should be compared. However, as the average number m increases, the iW standard deviation is attenuated by several tens of degrees compared to m=1. If the signals of each element are completely independent, the signal should be c) in proportion to (m)2. In reality, it seems to be between this 100-chi correlation and completely independent non-correlation, and it can be seen that the present invention is effective. In Fig. 4(b), the input signal is split into two, and each signal is 2cxs2πνt. 2Sif1
The reference signal is multiplied by 2πνt to generate sum and difference signals between the input signal frequency band and the frequency ν, and the sum signal is removed by a low-pass filter LPF to provide outputs kI and Q, respectively.

These I and Q are respectively called in-phase components and quadrature components of the orthogonal detection output. This orthogonal detection is a linear calculation process. This I
Using and Q, each moment of the spectrum is calculated in the time domain. For example, if we take Mife's first moment, M0 = <I + Q > M, = < IQ - IQ> where 〈〉 represents the time differential of 〈〉, and <> represents the average within a certain time window. In the figure, Me and Ml are circuits that perform this calculation. Each of these order moments is a quantity obtained from I and Q by nonlinear calculation, and the result of adding (averaging) each of them using Σ becomes Mo and Ml with less superimposed distortion. From this Mo, Ml, the center frequency f is Ml f==M.

, and the error due to superimposed distortion is reduced compared to the center frequency found only from the normal signal. The differentiation of f by 2 gives the damping coefficient slope β described above.

@4 Figure (c) is performed by logarithmic transformation of the input signal 'i LOG, and its envelope detection is performed by t-ED. LOG is a nonlinear process. Average the output by Σ,
Furthermore, time differentiation is performed with respect to π. FV is a nonlinear processing circuit such as frequency detection that converts frequency into a voltage signal, and its output is similarly averaged by Σ. ÷ is a divider circuit whose output gives an attenuation slope β in a medium with a frequency proportional attenuation constant such as a living body. The error due to the superimposed distortion of β is reduced by the swinging average compared to when only the normal signal is obtained by the same processing.

Alternatively, non-linear processing for calculating the square of the sound pressure may be included in place of the oscillation, which smooths out so-called speckles by means of a swinging average and is useful for improving the image quality of B-mode video. Generally, the B mode is often logarithmically compressed, and in this case, the speckle tm can be reduced by simply averaging the ED ratio output fluctuation after logarithmization.

Nonlinear processing is not limited to the above example.

In the above description, the delay is caused by a delay element, but other means having the same function may be used instead.

For example, all output signals of each element are A/D converted and stored,
By extracting and processing the A/D converted signal at the corresponding swing delay position at the corresponding time from the memory, all the delay elements can be replaced.

Instead of the above-mentioned electronic delay, acoustic lenses, prisms, plates with various thicknesses, etc. made of materials with a sound speed different from that of biological media can be mechanically distorted, moved, or vibrated. Sound can also be used as a means of doing so.

〔Effect of the invention〕

According to the present invention, multiple types of delayed fluctuations are added to the normal output in one scan to obtain one or more fluctuation outputs, and nonlinear averaging processing is performed on the fluctuation outputs including the normal output. In other words, by performing oscillating averaging, it is effective to reduce the superimposed distortion caused by the inhomogeneous medium of the ultrasonic signal and the resulting error in the induced value measurement value, and improve the spatial resolution and real-time performance. s' can be realized.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a series delay swing which is an embodiment of the present invention, Fig. 2 is a block diagram of a parallel delay swing which is another embodiment of the present invention, and Fig. 3 is a block diagram of a series/parallel compound swing. Figure 4 (a)
) or c) are representative examples of nonlinear averaging, as shown in Figure 4(a).
is power spectrum calculation, Fig. 4(b) is calculation of each order spectral moment from quadrature detection output, Fig. 4(c)
is an example using logarithmic calculation and frequency-voltage calculation. In the figure, Xj is a transducer element, SDj is a switch and delay circuit for dynamic aperture φ focusing control, and Σ is an addition (
average) circuit, ORD, SIG are normal signals, NLA is a nonlinear average circuit, τzi, τ, ij are delay times, Dzi,
Delay circuit corresponding to Drij tri, Ol is parallel delay swing output, PDW is parallel delay swing circuit, SDW is series delay swing circuit, G is gate circuit, FFT is Fourier transform circuit, 5 (f) is power spectrum Arithmetic circuit, X is a multiplication circuit, LPF is a low-pass filter, Mo, M. are the 0th and 1st order spectral moment calculation circuits, ÷
is a division circuit, LOG is a logarithmic calculation circuit, ED is an envelope detection circuit, 'FV is a frequency-voltage conversion circuit, and ■ is a differentiation circuit. FIG. 5 is a graph showing the effects of the present invention, in which the vertical axis S shows the standard deviation of fluctuations due to spectral scalloping, and the horizontal axis m shows the total number of elements to be oscillated. NLA's -1911 circuit concave Fig. 4 (α) NLA's concise circuit diagram 4 (21 (b) Singing NLA's -1911 circuit 1 4th concave (C) Rough showing the effect of Keibanro Figure 5'

Claims (7)

[Claims] (1) By adding a plurality of different delay times to a series of ultrasonic reception signals obtained from a set of transducers (Xj) consisting of a single transducer or a plurality of transducers, means (SDW,
What is claimed is: 1. An ultrasonic medium measuring device comprising: (PDW); and means (NLA) for performing nonlinear processing on each of the plurality of signals and then adding the processing results. (2) The above-mentioned vibrator is composed of a plurality of vibrators (X1 to Xn), and includes means (SD1 to SDn, Σ) for giving different delay times to the received signals from each vibrator and adding them, The extraction means (SDW, ) is provided with a plurality of delay means (Dz1 to Dzp) each giving a plurality of different delay times, and by giving the output of the addition means (Σ) to the extraction means (SDW), the normal line The ultrasonic medium measuring device according to claim 1, characterized in that a plurality of signals corresponding to received signals from a plurality of measurement points on a direction (Z-axis) are extracted simultaneously. (3) The above-mentioned transducer consists of a plurality of transducers (X1 to Xn), and the above-mentioned extraction means (PDW) adds a plurality of different combinations of delay times to each set of plural reception signals from the transducer. a plurality of sets of delay means (Drli to Drqi); and
A plurality of adding means (Σ1
~Σq), and simultaneously extracts multiple signals corresponding to received signals from multiple measurement points displaced not only in the normal direction (Z-axis) but also in the direction crossing the normal direction (X-axis). An ultrasonic medium measuring device according to claim 1, characterized in that: (4) further comprising delay means (SD1 to SDn) between the plurality of transducers (X1 to Xn) and the extraction means (PDW) for adding different delay times to the received signals from each transducer; 4. The ultrasonic medium measuring device according to claim 3, wherein the delay time of the delay means (SD1 to SDn) is changed over time to perform dynamic focusing control. (5) The extraction means (PDW) further includes each addition means (Σ
) includes delay means (SDW1 to SDW4) for adding a plurality of different delay times to the output of the nonlinear addition means (NLA), and provides the output to the nonlinear addition means (NLA). Ultrasonic medium measuring device. (6) The vibrator is composed of a plurality of vibrators (X1 to Xn), and the vibrator is divided into a plurality of groups (a to d), and the extraction means extracts each vibration of each group for each group. A plurality of sets of delay means that add a plurality of different combinations of delay times to a set of a plurality of received signals from a child, and a plurality of addition means (PDW1 to
PDW4) and a delay means (PDW4) for adding a plurality of different delay times to each of the plurality of outputs.
4. The ultrasonic medium measuring device according to claim 3, further comprising: SDW1 to SDW4), the output of which is supplied to the nonlinear addition means (NLA). (7) The nonlinear processing according to any one of claims 1 to 6, wherein the nonlinear processing includes any one of Fourier transform, orthogonal detection, logarithmic calculation, envelope extraction, or square calculation. Ultrasonic medium measuring device.