JPH0824258A - Ultrasonic transmitting and receiving method and apparatus using dispersion compression method - Google Patents

Abstract

PURPOSE:To obtain an accurate ultrasonic image by transmitting a pulse with a frequency being changable with time to an object to be examined and obtaining an ultrasonic image prepd. by phase adjusting and adding a compressed signal of a received echo signal. CONSTITUTION:A pulse with a frequency being changable with time is given to an ultrasonic probe 10 and it is transmitted to an object to be examined. An echo generated from an echo source is received by the ultrasonic probe 10 and is entered into an array synthesis part 11 through a transmitter/receiver circuit. The array synthesis part 11 synthesizes signals received by four pieces of elements and outputs it and in each compression filter 12, folding operation is performed and a pulse with a short time width is respectively output from each compression filter 12. A variable delay lens 13a performs time delay for focusing in accordance with the echo source and a directional angle setting part 13b performs a delay in accordance with the number of sound line and adjusts the phase to determine the directional angle in accordance with sector scanning. In addition, echo data are mapped on a video memory to display an ultrasonic image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave transmitting / receiving method and an ultrasonic wave transmitting / receiving apparatus using a dispersion compression method.

[0002]

2. Description of the Related Art In recent years, ultrasonic diagnostic equipment has been used in the field of medical diagnosis. This ultrasonic diagnostic apparatus transmits ultrasonic waves to a subject, receives echoes reflected from boundaries of the subject having different acoustic impedances, processes the signals, and displays them on a display device. A dynamic focus method is used as a technique for displaying the echo image on a display device in real time at high speed.

In the dynamic focus method, ultrasonic waves are transmitted from a wave transmitter / receiver (ultrasonic probe) to a subject, and echoes reflected from the subject are adjusted in focal length for each of a plurality of echo sources. It is then collected and displayed on the display device. FIG. 8 is an explanatory diagram of the dynamic focus method. When an ultrasonic wave is transmitted from an ultrasonic probe (not shown) to the subject, an echo is generated from the boundary where the acoustic impedance of the subject is different as shown in the figure.

Therefore, an electronic lens 1 as shown in the figure is arranged at the rear stage of the transmitter / receiver, and the echoes reflected from the echo sources A, B, C, and D are dynamically focused, and the processing circuit at the rear stage is processed. Take in. Electronic lens 1
Is composed of a plurality of delay elements, and performs focus adjustment by matching the phases of the outputs of the ultrasonic transducers (elements) of the wave transmitter / receiver. First, the echo from the echo source A is captured by the electronic lens 1, and then the echo source B
The echoes from the above are taken in, and hereinafter, the echo source C and the echo source D are taken in order. In such a series of processing, the electronic lens 1 electrically adjusts the delay amount of the element of each transducer according to the position of each echo source, and
The operation of converging to a point and adding the output of each element is performed.

As another technique of the ultrasonic diagnostic apparatus,
A method of transmitting an ultrasonic pulse whose frequency has changed with time from a transmitter / receiver, obtaining the correlation between the transmitted signal and the received signal during reception, and obtaining a signal that is shortened (that is, compressed) on the time axis ( The distributed compression method) has come to be used.

FIG. 9 is a diagram for explaining the operation of the distributed compression method. When a pulse having a frequency changed with time is transmitted from the pulse transmitter / receiver, its echo (received signal) also has a frequency changed with time. (A) of the figure shows the echo signal waveform received at this time. τ is the echo signal s (t)
Is the time width of. This echo signal s (t) enters the compression filter 2 and is filtered.

The compression filter 2 has the same waveform as the transmitted pulse as a coefficient, and performs a convolution operation (convolution operation) with the input signal s (t). Let the transfer function of this compression filter 2 be h (t). As a result of the convolution operation, a short pulse as shown in FIG.
Obtained as (t).

In the dispersion compression method as described above, the frequency is temporally adjusted so that the total energy is the same as one large-amplitude pulse transmission without performing one large-amplitude pulse transmission. By transmitting the changed pulse,
Since the transmitted energy to the subject is the same, the reach distance of the transmitted pulse can be extended. When the pulse reaching distance is not extended, the transmission frequency can be increased, so that the spatial resolution is improved and the focused transmission can be performed. Therefore, the resolution can be improved, and therefore, it has been used in recent years.

[0009]

When the dispersion compression method described above is combined with the dynamic focus method and applied to an ultrasonic diagnostic apparatus, there are the following problems. That is, since beam forming is performed for each echo source of the dynamic focus, if the compression is performed after the beam forming, an accurate output cannot be obtained. During compression (that is, during the convolution operation), time must not be extended (change the time axis; hereinafter the same). However, when the dynamic focus method is used, it is necessary to extend the time axis of the signal because it is necessary to perform variable focus adjustment. If a convolution operation is performed with a signal companding time as an input, a correct result cannot be obtained.

The present invention has been made in view of the above problems, and an object thereof is to provide an ultrasonic transmitting / receiving method and a transmitting / receiving apparatus using a dispersion compression method capable of obtaining an accurate ultrasonic image. There is.

[0011]

A first invention for solving the above-mentioned problems is to transmit a pulse whose frequency is changed with time toward a subject and compress the received echo signal,
It is characterized in that an ultrasonic image is obtained by phasing and adding the compressed signals.

Further, it is preferable to perform the compression for each array in which a plurality of ultrasonic transducers of the ultrasonic probe are put together, because the hardware circuit in the subsequent stage can be reduced.

Further, the received echo signal is temporarily stored in an echo memory, the echo data is sequentially read out from the echo memory, and the compression and phasing / addition processing is performed by using a digital signal processor to perform super-processing. Obtaining a sound wave image is preferable because the number of hardware circuits can be reduced.

A second invention for solving the above-mentioned problems, means for transmitting a pulse whose frequency is changed with time toward a subject, and means for compressing the received echo signal,
It is characterized by comprising means for phasing and adding the compressed signals to obtain an ultrasonic image.

Further, an ultrasonic probe for transmitting and receiving ultrasonic waves is divided into an array grouped by a plurality of ultrasonic transducers, and the compression means is provided for each divided array. It is preferable because the number of hardware circuits can be reduced.

Further, an echo memory for storing the received echo signal and a digital signal processor are provided, and the digital signal processor sequentially reads out the echo data from the echo memory for compression and phasing / addition processing. Is preferable to obtain an ultrasonic image because it is possible to reduce the number of hardware circuits.

A third invention for solving the above-mentioned problems is a means for transmitting a pulse whose frequency is changed with time toward a subject, and a plurality of means for adjusting the phase of the received echo signal for focusing. Of the fixed delay lens, a compression filter for compressing the outputs of the fixed delay lenses, and a changeover switch for selecting one of the outputs of the compression filters.

[0018]

[Action]

(First invention) When the dispersion compression method is used, time must not be extended until the echo from the echo source is received and the echo is applied to the compression filter. However, when the dynamic focus method is used, it is necessary to extend the time because it is necessary to perform variable focus adjustment. Therefore, after applying the compression filter, the dynamic focus is performed.
That is, the received echo signal is first compressed, and then the compressed signal is phased and added. In this way, when compressing, the input signal is not companded in time and an accurate compressed output is obtained. Accurate ultrasonic images (echo images) can be obtained because the correctly compressed signals are phased and added.

(Second invention) The means for compressing the received echo signal is brought before the means for phasing / adding the echo signals. Therefore, as in the case of the first aspect of the invention, it is possible to compress an input signal that has no time companding, and then perform phasing and addition, and the obtained ultrasonic image is also accurate.

Further, if the ultrasonic probe is divided into an array for each of a plurality of ultrasonic transducers, the hardware circuit in the subsequent stage can be reduced. Furthermore, if compression processing and phasing / addition processing are performed by a digital signal processor,
Hardware circuits such as compression filters and beamformers are not needed.

(Third invention) When a fixed delay lens having a fixed delay time for the dynamic focus delay lens is used, there is no time companding inside the fixed delay lens, so a compression filter is provided after the fixed delay lens. Even if you bring it, you can get accurate output.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flow chart showing the principle of the method of the present invention, and FIG. 2 is a configuration block diagram showing an embodiment of the present invention. According to the method of the present invention, a pulse whose frequency is changed with time is transmitted toward a subject (S1), the received echo signal is compressed (S2), and the compressed signal is phased / added to obtain a supersonic signal. The feature is that a sound wave image is obtained (S3).

In the apparatus shown in FIG. 2, the wave transmission system is omitted. Actually a beamformer for transmission,
A transmitter / receiver circuit is provided which applies ultrasonic pulses to the ultrasonic probe and receives echoes. Then, a pulse whose frequency is changed with time is applied from the transmitter to the ultrasonic probe, and is transmitted from the ultrasonic probe toward the subject. In the figure, 10 is an ultrasonic probe that transmits an ultrasonic wave and receives an echo.
As shown in the figure, it is composed of a plurality of elements (ultrasonic transducers). Reference numeral 11 is an array combining unit that receives and combines echoes in units of four elements. Practically, even if the wave is received / combined for each of the four elements and processed, the wave is received for each element alone, and an image comparable to that obtained by the image processing can be obtained. In this way, by collectively receiving and synthesizing a plurality of elements, it is possible to reduce the number of subsequent hardware circuits. Note that the unit of wave reception / combination is not limited to four, and any number of elements capable of obtaining an ultrasonic image comparable to that received by each element even if wave reception / combination is used. It can be a unit.

Reference numeral 12 is a compression filter that receives the output of each array synthesizing unit 11 to perform a convolution operation to obtain a pulse with a short time width. It is composed of a lens 13a and an azimuth angle setting unit 13b. Reference numeral 13a is a variable delay lens (electronic lens) for dynamic focus which receives the output of each compression filter 12. The variable delay lens 13a is composed of variable delay elements D as many as the compression filters 12, and the time delay amount can be varied for each echo source. 13b
Is an azimuth angle setting unit that receives the output of each variable delay lens 13a, delays the sound ray number given from a controller (not shown), adjusts the phase, and determines the azimuth angle according to the sector scan. . The azimuth setting unit 1
A post-processing circuit (not shown) for image processing is provided at the subsequent stage of 3b to display the processed echo image on the display device. The operation of the apparatus configured as described above will be described below.

First, a pulse whose frequency is changed with time is given to the ultrasonic probe 10 from a transmission system (not shown),
The ultrasonic probe 10 transmits a wave toward a subject (not shown). As a result, an echo is generated from the boundary where the acoustic impedance of the subject is different, as shown in FIG. The echo generated from each echo source is received by the ultrasonic probe 10. The received echoes are transmitted to the array synthesizing unit 1 via a transmitter / receiver circuit (not shown).
Enter 1.

The array synthesizing section 11 synthesizes the received signals of the four elements and outputs them. The output of each array synthesizer 11 enters a respective compression filter 12. A convolution operation is performed in each compression filter 12, and a pulse with a short time width is output from each compression filter 12. In the present invention, since the signal input to the compression filter 12 is a signal that is not time-compressed, correct compression processing can be performed. Each variable delay lens 13a receives the output of each compression filter 12 and delays the time for focusing according to the distance of the echo source. The echo signals focused by the variable delay lens 13a enter the azimuth angle setting unit 13b. The azimuth setting unit 1
3b performs a delay according to a sound ray number given from a controller (not shown), adjusts the phase, and determines an azimuth angle according to a sector scan.

FIG. 3 is an operation explanatory view of the variable delay lens 13a and the azimuth angle setting section 13b. The variable delay lens 13a is for adjusting the phase of the echo that does not include the azimuth component, as shown in FIG. FIG. 6A shows a state of phase adjustment of an echo that does not include an azimuth component. In FIG. 3A, 30 is an echo source existing on the sound ray 31, and 32 is a wavefront perpendicular to the sound ray 31. The variable delay lens 13a delays the phase of each echo so that the echoes from the echo source 30 are aligned on the wavefront 32.

For example, of the echoes from the echo source 30,
The echo along the innermost ray 30 is the fastest wavefront 32
And the echo outside of it reaches the wavefront 32 toward the outside.
Reach late. In order to make the phases of such echoes uniform on the wavefront 32, the variable delay lens 13a makes the delay time of the middle echo the longest, and shortens the delay time toward the outside. By such phase adjustment, the wavefront 3
The phases of the echoes are aligned on 2. The delay amount in this case becomes a quadratic curve as shown in the figure. In the case of dynamic focus, the echo source 30 is not limited to the position shown in the figure, and there are a plurality of echo sources as shown in FIG. Therefore, the variable delay lens 13a is
It is necessary to perform an operation for promptly aligning the phases on the wavefront 32 with respect to the echoes from a plurality of echo sources existing on one sound ray, and a high speed operation is required.

FIG. 3B shows how the phase of the echo including the azimuth component is adjusted. 32 in the figure is (a) in FIG.
Is the same as the wavefront 32 shown in FIG. Variable delay lens 13
Even if the wavefront 32 has the same phase at a, it will be incident on the ultrasonic probe 10 at an angle θ depending on the azimuth angle. In this case, the upper echo reaches the ultrasonic probe 10 faster, and the lower echo reaches the ultrasonic probe 10 later. Therefore, the azimuth angle setting unit 13b uses the ultrasonic probe 10
In order to adjust the phase in terms of, the time is delayed for each echo and the phase is adjusted. The delay amount in this case is
It becomes a linear curve as shown in the figure. The phase adjustment amount of the azimuth angle setting unit 13b is fixed by the sound ray number. If the sound ray number is different, the angle θ in the figure changes, so the amount of phase adjustment also changes. Since the phase adjustment amount is fixed for one sound ray number, the azimuth angle setting unit 13b includes the variable delay lens 13
The high speed operation as a is not required.

The azimuth angle setting unit 13b phases and adds the outputs of the variable delay lens 13a, and then passes them to the processing circuit in the subsequent stage. In the subsequent processing circuit, after processing the echo signals (for example, logarithmic compression and detection), each echo data processed by the DSC (dynamic scan converter) is mapped to a predetermined position on the video memory and scanned. An ultrasonic image (echo image) is displayed on the display device by changing the direction.

According to the present invention, an accurate echo image can be obtained even in the case of using the dispersion compression method in an ultrasonic diagnostic apparatus using dynamic focus. That is, according to the present invention, as a result of using the dispersion compression method, an echo image of a deep portion of the subject can be displayed at high speed in real time.

FIG. 4 is a block diagram showing the configuration of another embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals. Also in this embodiment, the transmission system is omitted.
In this embodiment, the echo data is once stored in the echo memory, and then the echo data is sequentially read from the echo memory using a digital signal processor (DSP) to perform compression processing, dynamic focus processing, phasing / phasing. The addition processing is performed. Figure 2
The embodiment shown in (3) is a real-time processing system without a portion for temporarily storing echo data. On the other hand, the present embodiment is a system in which the echo data is temporarily stored in the echo memory and then processed. As a result, it takes some time to display the received echo data on the display device. However, the time delay is the frame rate 1
/ 30 seconds or less, which is practically no problem.

In FIG. 4, reference numeral 10 denotes an ultrasonic probe for transmitting and receiving ultrasonic waves, which is composed of a plurality of elements as shown in the figure. Reference numeral 11 is an array synthesizing unit provided in units of groups of four elements. In practical use, there is no problem even if the four elements are received, combined, and processed. Note that the unit of wave reception / combination is not limited to four, and an arbitrary number of elements can be used as a unit within a range in which the quality of an image signal is not deteriorated even if wave reception / combination is performed. . Reference numeral 16 is an A / D converter that converts the output of each array synthesis unit 11 into digital data.

Reference numeral 17 is an echo memory for temporarily storing the output of each A / D converter 16. Reference numeral 18 is a digital signal / signal for sequentially reading data from the echo memory 17 for compression filter processing, dynamic focus processing and beam forming processing. Processor (DSP) group (array)
Is. Specifically, the DSP array 18 is composed of a plurality of DSPs, and the respective DSPs share the processing to execute the above processing. An image memory 19 stores the output of the DSP array 18. The operation of the apparatus configured as described above will be described below.

The operation of transmitting a pulse whose frequency is changed from the ultrasonic probe 10 to the subject, receiving the echo by the ultrasonic probe 10, and synthesizing the echo by the array synthesizing unit 11 is as shown in the figure. This is the same as the second embodiment. The output of each array synthesizer 11 is converted into digital data by the A / D converter 16 and then stored in the echo memory 17.

In the DSP array 18, each internal DSP sequentially reads the echo data of its own portion from the echo memory 17 by its own program, and first performs a compression filter operation by a convolution operation. Next, local time axis compression is performed for the adjustment operation (dynamic focus) that causes the focus to follow the data compressed by the convolution calculation according to the distance from the echo source. Next, after the time alignment (and phase adjustment if necessary) corresponding to the azimuth angle is performed on the data for which the time axis alignment for the focus tracking adjustment is completed, echoes corresponding to all the arrays are obtained. Add the data.

The above-described operation is performed by the DSP for the phasing / addition procedure.
This is an outline of execution as a processing procedure described in software by using time division and space division together in the array 18. In this case, as is common sense, the accommodation form of the echo data in the echo memory 17 has a one-to-one correspondence between the address and the arrival time. And all the time adjustment work is a procedure description in the form of which address (time) of data is transferred from the software by what kind of weight and where, or cumulative addition is performed.

The DSP is good at such a product-sum operation or convolution operation. Therefore, in such a configuration using the DSP array 18, a large number of inexpensive DSPs are individually operated in parallel, so that the dynamic focus can be used without using any dedicated ICs or LSIs that are expensive and time-consuming to develop. The point is that wave beamforming can be performed.

The data thus phased / added is stored in the subsequent image memory 19. Image memory 19
The data stored in is sequentially read out, sent to the processing circuit in the subsequent stage, subjected to predetermined signal processing, and then displayed on the display unit.

According to the embodiment shown in FIG. 4, after the echo data is temporarily stored in the echo memory 17, the echo data is sequentially read out to obtain the DS.
Since the P array 18 is processed, a time delay occurs. However, this time delay is 1/30 as described above.
It can be set within a second and there is no problem in practical use. According to this embodiment, since the DSP array 18 can be made to perform a series of processes of the compression filter process, the dynamic focus process, and the phasing / addition process, the compression filter,
An inexpensive device can be provided without needing a variable delay lens or a beam former. In the ultrasonic diagnostic apparatus using the dynamic focus, the effect that an accurate echo image can be obtained even when the dispersion compression method is used is the same as in the embodiment of FIG.

FIG. 5 is a block diagram showing the configuration of another embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals. Also in this embodiment, the configuration of the transmission system is omitted. In the figure, the ultrasonic probe 10 is assumed to be composed of 64 elements. 20 is an amplifier for amplifying the output of each element, 21 is an amplifier 20 64
It is a fixed delay lens that receives each output simultaneously and performs dynamic focusing and phasing (beamforming). In the figure, the focal lengths are f1, f2 and f3, respectively.
However, the number is not limited to three.

A compression filter 22 receives the output of each fixed delay lens 21 and performs compression. Reference numeral 23 denotes a changeover switch which receives the output of each compression filter 22 and gives it to the circuit in the subsequent stage in the order of echo time. The operation of the apparatus configured as described above will be described below.

In the same manner as in the embodiment shown in FIG. 2, the ultrasonic probe 10 transmits a pulse whose frequency is changed with time to the subject, and the ultrasonic probe 10 receives an echo. The received echo signal is amplified by the amplifier 20 for each element and output. The output of the amplifier 20 enters the three fixed delay lenses 21 at the same time.

Each of the fixed delay lenses 21 applies a focus adjustment delay to the input signal of each element and then performs beam forming (phase adjustment). Then, the phased echo signals are added and output from each fixed delay lens 21. The output of each fixed delay lens 21 enters the subsequent compression filter 22 and the convolution operation is performed. As a result, an echo pulse having a shorter time width is obtained from each compression filter 22.

By the way, the outputs of the respective fixed delay lenses 21 are properly focus-adjusted, phased and added, only those corresponding to the distance of the echo source. Therefore, the change-over switch 23 switches the output of each compression filter 22 so that the correct echo signal is taken into the subsequent circuit in the order of echo time. As a result, the output of the change-over switch 23 is sent to the processing circuit in the subsequent stage, predetermined signal processing is performed, and an echo image is displayed on the display device.

In the system in which an electron lens having a fixed focal length is provided in advance as in this embodiment, the image of the echo source corresponding to the focal length can be focused.
If there is another echo source between the first echo source and the second echo source, and there is no electron lens having a focal length corresponding to the echo source, the echo at that point cannot be focused. . However, since it is a fixed focus method,
No time is stretched inside the electron lens. Therefore, in this embodiment, an accurate output can be obtained even if the compression filter is provided after the electron lens. That is, in an ultrasonic diagnostic apparatus using dynamic focus, an accurate echo image can be obtained even when the dispersion compression method is used.

When the combination focusing is performed together with the wave transmission, the time width τ of the wave transmission (see FIG. 9)
May be variable according to the zone. For example,
Large-amplitude transmission is not necessary for short-distance zones, so 1
In the case of a medium-distance zone, τ transmits a short width, and in the case of a long-distance zone, τ corresponds to a large amplitude transmission, and τ transmits a long width. To

In the present invention, as the ultrasonic probe, in addition to a normal array, an annular array (annular array) as shown in FIG. 6 can be used. Unlike ordinary arrays, the annular array cannot perform sector scan by phase adjustment, but its direction is fixed, but its annular element arrangement has excellent dynamic focus characteristics.

Further, according to the present invention, distributed compression type transmission / reception is performed for each array of ultrasonic transducers (elements) or a plurality of elements, and compressed data is stored in a memory each time, and all elements are stored. Alternatively, an aperture synthesis method may be adopted in which beamforming is performed after the data of all the arrays are stored in the memory. With such a configuration, the hardware can be reduced and the circuit can be simplified.

When multi-beam forming is applied to the present invention, it is necessary to provide a set of compression filter and beam former for each beam to be combined. FIG. 7 shows a configuration for realizing multi-beam forming (a method in which a plurality of receiving systems with slightly different directivities are prepared to obtain echo data of several sound rays at once in one transmission) Here is an example: The same parts as those in FIG. 2 are designated by the same reference numerals. As shown in the figure, the configuration shown in FIG. 2 is provided for each combined beam (sound ray).

[0051]

As described above in detail, according to the present invention, a pulse whose frequency is changed with time is transmitted toward the subject, the received echo signal is compressed, and the compressed echo signal is compressed. An accurate ultrasonic image can be obtained by phasing and adding the signals to obtain an ultrasonic image.

Further, according to the present invention, means for transmitting a pulse whose frequency is changed with time toward the subject, means for compressing the received echo signal, and phasing / compressing the compressed signal An accurate ultrasonic image can be obtained by providing a means for adding to obtain an ultrasonic image.

Further, the ultrasonic probe for transmitting and receiving ultrasonic waves is divided into an array which is grouped for each of a plurality of ultrasonic transducers, and the compression means is provided for each divided array, thereby providing hardware. The number of circuits can be reduced.

Further, an echo memory for storing the received echo signals and a digital signal processor are provided, and the digital signal processor sequentially reads out the echo data from the echo memory for compression and phasing / addition processing. The hardware circuit can be reduced by performing the above procedure to obtain an ultrasonic image.

Further, according to the present invention, means for transmitting a pulse whose frequency is changed with time toward the subject, and a plurality of fixed delay lenses for adjusting the phase of the received echo signal to focus the echo signal. An accurate ultrasonic image can be obtained by including a compression filter that compresses the outputs of these fixed delay lenses and a changeover switch that selects one of the outputs of these compression filters.

[Brief description of drawings]

FIG. 1 is a flow chart showing the principle of the method of the present invention.

FIG. 2 is a configuration block diagram showing an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of a variable delay lens and an azimuth angle setting unit.

FIG. 4 is a configuration block diagram showing another embodiment of the present invention.

FIG. 5 is a configuration block diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing an appearance of an annular array.

FIG. 7 is a diagram showing a configuration example in the case of realizing multi-beam forming.

FIG. 8 is an explanatory diagram of a dynamic focus method.

FIG. 9 is an operation explanatory diagram of the distributed compression method.

[Explanation of symbols]

 10 Ultrasonic Probe 11 Array Synthesizing Section 12 Compression Filter 13 Beamformer 13a Variable Delay Lens 13b Azimuth Setting Section

Claims (5)

[Claims] 1. An ultrasonic image is obtained by transmitting a pulse whose frequency is changed with time toward a subject, compressing the received echo signal, and phasing and adding the compressed signal. An ultrasonic transmission / reception method using a distributed compression method. 2. A means for transmitting a pulse whose frequency is changed with time toward a subject, a means for compressing a received echo signal, and phasing and adding the compressed signal to obtain an ultrasonic wave. An ultrasonic transmitting / receiving apparatus using a dispersion compression method, which comprises a means for obtaining an image. 3. An ultrasonic probe for transmitting and receiving ultrasonic waves,
The ultrasonic wave using the dispersion compression method according to claim 2, wherein the ultrasonic wave is divided into an array grouped by a plurality of ultrasonic transducers, and the compression means is provided for each divided array. Transceiver. 4. An echo memory for storing received echo signals and a digital signal processor are provided, and the digital signal processor sequentially reads echo data from the echo memory for compression and phasing / addition processing. The ultrasonic transmitting / receiving apparatus using the dispersion compression method according to claim 2, wherein the ultrasonic image is obtained by performing the above. 5. A means for transmitting a pulse whose frequency is changed with time toward a subject, a plurality of fixed delay lenses for adjusting the phase of the received echo signal to focus the same, and these fixed delay lenses. An ultrasonic transmission / reception apparatus using a dispersion compression method, which comprises a compression filter for compressing the output of the compression filter and a changeover switch for selecting one of the outputs of these compression filters.