JP3502700B2 - Ultrasound diagnostic imaging equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic echo (ech).
The present invention relates to an ultrasonic diagnostic image forming method and apparatus for forming an image of a subject by using o). For more details,
An ultrasonic diagnostic image forming method and apparatus for performing various kinds of signal processing for image formation in a transform domain such as a frequency domain on an echo reception signal.

[0002]

2. Description of the Related Art Conventionally, signal processing in an ultrasonic diagnostic apparatus has been digitized. In recent years, digitization has been thoroughly implemented, and an "all digital" ultrasonic diagnostic apparatus in which all signal processing systems are digitized except for an ultrasonic transmission / reception system which must be analog has also appeared.

Since an array of a plurality of ultrasonic transducer elements is generally used for transmitting and receiving ultrasonic waves, a plurality of channels obtained by such an array are used.
In order to form an image from the echo reception signal of (channel), for example, beam forming or beam forming
(pulse) compression (range compr
array signal processing, which is typified by ession)).

Beam forming is performed by delaying and adding an echo reception signal group in a time domain or a phase domain, and pulse compression is performed by convolution.
It is calculated.

Since it is conventional for ultrasonic diagnostic equipment to display diagnostic images in real time, the digital processing of the array signals must be fast enough to allow it.

Such high-speed array signal processing is currently carried out by commercially available DSP (digital signal processor) and MPU (micro).
The signal processing units such as beam forming and pulse compression are each configured with a dedicated LSI (large scale integrated circuit) because the capability of the processor is not reached.

[0007]

[Problem to be Solved by the Invention] Producing a dedicated LSI means that the signal processing unit is a so-called silicon.
In general, the design trial of equipment including siliconization has a very long cycle time and enormous man-hours and cost, so trial and error at the final fine adjustment stage of design is required. The degree of freedom is greatly limited, and
There is a problem that there is almost no flexibility on the side of the device that immediately responds to new applications.

In order to avoid such a problem, in order to avoid trial and error at the final stage, a perfect simulation and design examination based on the know-how of the analog age are performed. Becomes essential,
In addition, it is necessary to incorporate preliminary resources into the design from the beginning in consideration of the possibility of adding a new application, but in reality it is not easy to implement.

Originally, the advantage of fully digitizing the apparatus is that the contents of the processing (software) and the hardware of the processing apparatus (hardware) can be completely separated and separately developed in parallel. That is, the degree of freedom in development should be dramatically improved, but the problem is that digitization by a dedicated LSI cannot produce such an advantage.

The present invention has been made to solve the above problems, and an object thereof is an ultrasonic diagnostic image forming method in which the contents of processing and the metal of the processing apparatus can be completely separated and separately developed in parallel. And to realize the device.

[0011]

According to a first aspect of the present invention, an ultrasonic wave is transmitted to a subject to receive an echo of the ultrasonic wave, and a received signal of the echo is converted into a digital signal. The digitally converted echo reception signal is converted into a signal in the transform domain, processing is performed on the echo reception signal in the transform domain to form a diagnostic image, and the processed signal is processed from the signal in the transform domain. It is an ultrasonic diagnostic image forming method characterized by inversely converting into a domain signal.

In the first aspect of the present invention, the transform domain is a signal domain in which the linearity of the operation with respect to the signal is maintained even when the signals are mutually converted between the transform domain and the real domain. That is.

An example of such a transform domain is a frequency domain by Fourier transform. It should be noted that the category of the transform domain includes not only the frequency domain but also other signal domains that are equivalent in operational effect.

Further, in the first aspect of the present invention, at least the following is included in the category of processing for forming the diagnostic image. Of course, the following are examples and are not meant to be limiting.

(1) Beam forming (2) Electronic focus (3) Aperture adjustment (4) Pulse compression (or range compression) (5) Filter processing (6) Doppler (or MTI (moving target indicatio)
n)) Processing (7) According to the first invention for solving the problem of total addition, the processing for forming the diagnostic image in the transform domain is performed on the digitally converted echo reception signal. The hardware of the processing device can be composed of general-purpose parts such as DSP, and the processing contents and the hardware of the processing device can be completely separated and separately developed in parallel.

A second invention for solving the problem is to transmit an ultrasonic wave to a subject, receive an echo thereof, convert a received signal of the echo into a digital signal, and receive the digitally converted echo. The signal is transformed into a signal in the frequency domain by Fourier transform, processing for forming a diagnostic image is performed on the echo reception signal in the frequency domain, and the processed signal is transformed from the signal in the frequency domain to the real domain by the inverse Fourier transform. It is an ultrasonic diagnostic image forming method characterized by performing inverse conversion into a signal.

The meaning of the process for forming the diagnostic image in the second aspect of the invention is as described above.
According to the second invention for solving the problem, since the processing for forming the diagnostic image in the frequency domain by the Fourier transform is performed on the digitally received echo reception signal, the hardware of the processing device is a DSP or the like. It can be composed of general-purpose parts, and the contents of processing and the hardware of the processing equipment can be completely separated and separately developed in parallel.

A third invention for solving the problem is a transmitting / receiving means for transmitting an ultrasonic wave to a subject and receiving an echo thereof, and an echo reception signal obtained by the transmitting / receiving means is converted into a digital signal. A first conversion means, and the first
Second converting means for converting the echo reception signal digitally converted by the converting means into a transform domain signal, and processing means for performing processing for forming a diagnostic image on the echo reception signal in the transform domain, An ultrasonic diagnostic image forming apparatus comprising: a third conversion unit configured to inversely convert the signal processed by the processing unit from the transform domain signal to the real domain signal.

The meaning of the transform domain and the meaning of the process for forming the diagnostic image in the third invention are as described above. According to the third invention for solving the problem, since the processing for forming the diagnostic image in the transform domain is performed on the echo-received signal which is digitally converted, the hardware of the processing device is a general-purpose device such as DSP. It can be composed of parts, and the contents of processing and the hardware of the processing equipment can be completely separated and separately developed in parallel.

A fourth aspect of the present invention for solving the problem is a transmitting / receiving means for transmitting an ultrasonic wave to a subject and receiving an echo thereof, and an echo reception signal obtained by the transmitting / receiving means is converted into a digital signal. A first conversion means, and the first
Second conversion means for converting the echo reception signal digitally converted by the conversion means into a frequency domain signal by Fourier transform, and processing means for performing a process for forming a diagnostic image on the echo reception signal in the frequency domain. An ultrasonic diagnostic image forming apparatus comprising: a third conversion unit that reverse-converts the signal processed by the processing unit from the frequency domain signal to the real domain signal by an inverse Fourier transform. .

The meaning of the processing for forming the diagnostic image in the fourth aspect of the invention is as described above.
According to the fourth invention for solving the problem, since the processing for forming the diagnostic image in the frequency domain by the Fourier transform is performed on the digitally received echo reception signal, the hardware of the processing device is a DSP or the like. It can be composed of general-purpose parts, and the contents of processing and the hardware of the processing equipment can be completely separated and separately developed in parallel.

A fifth aspect of the invention for solving the problem is a transmitting / receiving means for transmitting an ultrasonic wave to a subject and receiving an echo thereof, and an echo reception signal obtained by the transmitting / receiving means is converted into a digital signal. A first conversion means, and the first
Second transforming means for transforming the echo reception signal digitally converted by the transforming means into a frequency domain signal by Fourier transforming the signal divided into a plurality of zones on the time axis, and the frequency. Processing means for performing processing for forming a diagnostic image on the echo received signal in the domain; and third processing for inversely transforming the signal processed by the processing means from the frequency domain signal to the real domain signal by inverse Fourier transform. An ultrasonic diagnostic image forming apparatus comprising: a converting unit.

The meaning of the process for forming the diagnostic image in the fifth aspect of the invention is as described above.
According to a fifth aspect of the invention for solving the problem, a signal obtained by dividing a digitally converted echo reception signal into a plurality of sections on the time axis is converted into frequency signals by Fourier transform, and the echo reception signal is obtained in the frequency domain. Since the processing for forming the diagnostic image is performed, the dynamic focusing of the ultrasonic beam can be realized.

A sixth aspect of the invention for solving the problem is a transmitting / receiving means for transmitting an ultrasonic wave to a subject and receiving its echo, and an echo reception signal obtained by the transmitting / receiving means is converted into a digital signal. A first conversion means, and the first
Second conversion means for converting the echo reception signal digitally converted by the conversion means into a frequency domain signal by Fourier transform, and processing for forming a B-mode diagnostic image for the echo reception signal in the frequency domain. A first processing means, a second processing means for performing processing for forming a dynamic mode diagnostic image on the echo reception signal in the frequency domain; and an inverse Fourier transform of the signal processed by the first processing means. Fourth transforming means for inversely transforming the frequency domain signal into a real domain signal by means of the above, and inversely Fourier transforming the signal processed by the second processing means into a real domain signal from the frequency domain signal. An ultrasonic diagnostic image forming apparatus comprising: a fifth converting unit for converting.

The meaning of the process for forming the diagnostic image in the sixth aspect of the invention is as described above.
Further, in the sixth aspect, the category of the dynamic mode includes at least the following. Of course, the following are examples and are not meant to be limiting.

(1) Doppler (or MTI) mode (3) CFM (color flow mapping) mode According to the sixth invention for solving the problem, a digitally converted echo reception signal is subjected to Fourier transform in the frequency domain. Since the process for forming the B-mode diagnostic image and the process for forming the dynamic mode diagnostic image are separately performed, it is easy to optimize each process.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a block diagram of the ultrasonic diagnostic apparatus. This device is an embodiment of the present invention. It should be noted that the configuration of the present apparatus shows an embodiment relating to the apparatus of the present invention. Also, the operation of the apparatus shows an embodiment relating to the method of the present invention.

2 and 3 are block diagrams showing the flow of signal processing in this apparatus. In FIG. 1, an ultrasonic probe 1 has an array of a plurality of transducer elements and transmits an ultrasonic beam to a subject (not shown) and detects an echo from the subject. The subject is scanned with an ultrasonic beam by the ultrasonic probe 1.

The transmitting / receiving array 2 drives the ultrasonic probe 1 to transmit an ultrasonic beam, receives an echo detection signal from the ultrasonic probe 1, and outputs an echo reception signal for each element as an analog / digital (A / D) signal. Convert to RF
(radio frequency) Write to echo memory 3.

The ultrasonic probe 1 and the transmitting / receiving array 2 are an embodiment of the transmitting / receiving means in the present invention. The transmitting / receiving array 2 is an embodiment of the first converting means of the present invention.

The echo echo signal waveform for each transducer element is digitally converted and stored in the RF echo memory 3. The echo reception signal per ultrasonic wave transmission is stored in one memory plane. A plurality of memory planes are provided and echo reception signals for a plurality of ultrasonic wave transmissions are stored. As a result, the hologram of the echo reception signal is stored in the RF echo memory 3.

That is, the processing of the processing block 11 of FIG. 2 is performed by the ultrasonic probe 1, the transmission / reception array 2 and the RF echo memory 3. The echo reception signal stored in the RF echo memory 3 is processed by the DSP array 4. The DSP array 4 is composed of a plurality of DSPs. In the DSP array 3, one DSP is provided for each sound ray, for example.

The DSP array 4 performs the processing of the processing blocks 12 to 14 among the processing blocks shown in FIG. That is, FFT for each channel and zone is performed on the echo reception data, and processing such as phase gradient addition, aperture weighting, filter processing, convolution, Doppler / MTI processing and total addition is performed on the FFT data for each channel / zone. Finally, iFFT is performed.

These processes by the DSP array 4 are performed by R
The echo data group stored in the F echo memory 3 is simultaneously executed in parallel or time division multiplex by a plurality of DSPs.

The DSP array 4 implements the second conversion means, the third conversion means, the fourth conversion means, the fifth conversion means, the first processing means, the second processing means and the processing means in the present invention. Is one form.

The phase tilting for each channel zone is related to beam forming and electronic focusing. Aperture weighting is related to beamforming. Convolution is related to pulse compression (range compression). Doppler / MTI processing is related to dynamic image processing such as CFM. The total addition is related to the formation of sound ray image data.

Upon convolution, the DSP array 4 processes the processing block 2 among the processing blocks shown in FIG.
Processes 3 to 26 are performed. That is, the FFT is performed on the echo reception data and the predetermined convolution kernel data, the two data are multiplied by the corresponding bins, and finally the iFFT is performed.

The convolution kernel data can be stored in advance by utilizing a part of the RF echo memory 3, for example. Of course, it may be written in a general-purpose memory.

Beamforming is a processing block 13
Is performed by adding a phase gradient for each channel / zone and total addition. That is, the delay addition including the precise interpolation of the signal waveform of the echo reception signal for each channel in the real domain is changed to the frequency domain by the FFT so that the complex amplitude of each bin has an inclined frequency phase characteristic. This is achieved by imposing different phase rotations and then adding the bins corresponding to the channel direction (space axis direction of the transducer array). This is because the expression in the frequency domain of the distortion-free delay has a linear frequency-phase characteristic.

The electronic focusing of the beam, in particular the dynamic focusing, is performed by applying the above-mentioned phase inclination to the echo data which has been FFT for each zone and editing the result.

Processing other than beamforming can be simultaneously executed in parallel by modifying the complex data string of the frequency domain bin. That is, weighted addition on the aperture plane of the array, fixed or adaptive filter processing and pulse compression processing for each channel, each distance, and each sound ray can be performed at the stage of the data string of this frequency domain bin.

In the convolution processing for the pulse compression processing, as shown in FIG. 3, the kernel or replica of the convolution partner is FFT'ed.
Therefore, if it is put up in the frequency domain in advance, the complex multiplication between the corresponding bins can be performed only once, and the repetition of the shift and the sum of products as in the real domain is unnecessary.

Also, the MTI process, that is, the Doppler extraction process, should be performed by the change extraction process between the pulses of the data string of the bin in the frequency domain, between the packets, between the fields, or between the frames. You can

Since it is necessary to return the above processing result to the time-axis waveform to finally obtain an image, the inverse Fourier transform (iFFT) is performed only once at the end. The iFFT-processed data is written in the coherent B / CFM memory 5 for each sound ray (direction). The data written in the coherent B / CFM memory 5 is, for example, B mode image data or C depending on the content of data processing in the DSP array 4.
It becomes FM image data.

In this case, different processing may be performed on the same array data in accordance with the request of the image to be obtained, and finally (corresponding sound ray data) of the corresponding image may be obtained by each iFFT. it can. Thereby, for example, a B-mode image and a CFM (color MTI) image can be processed simultaneously in parallel.

Since such data processing is suitable for being carried out by a DSP or MPU, the hardware of the processing device can be realized by general-purpose parts instead of a dedicated LSI. Therefore, complete separation of hardware and software and independent parallel development are possible.

Also, a design with a short cycle time using only general-purpose parts and a modular design that enables adaptation to expansion and contraction of the scale of the apparatus are possible. Further, it is not necessary to redesign the other generation of hardware or software, and improvement in the final stage of design can be dealt with in a short time by reworking software.

Further, since the improvement by software is easy to describe as know-how, it is convenient to accumulate and transmit it across generations. Coherent B / C
The image data written in the FM memory 5 is given to the display unit 7 through the display manager 6 and displayed as an image. At that time, the display manager 6 performs the processing of the processing block 15 in FIG. 2, that is, the processing such as logarithmic compression, video processing, measurement, and display.

[0049]

As described in detail above, according to the first invention for solving the problem, the processing for forming the diagnostic image is performed in the transform domain, so that the processing apparatus is a metal item. Can be constituted by general-purpose components such as DSP, and the effect that an ultrasonic diagnostic image forming method can be realized in which the processing contents and the metal parts of the processing device are completely separated and can be separately developed in parallel can be obtained.

Further, according to the second invention for solving the problem, since the processing for forming the diagnostic image is performed by frequency main, the hardware of the processing apparatus can be constituted by general-purpose parts such as DSP. The effect that the ultrasonic diagnostic image forming method can be realized in which the processing contents and the hardware of the processing device are completely separated and can be separately developed in parallel can be obtained.

Further, according to the third invention for solving the problems, the processing for forming the diagnostic image is performed in the transform domain, so that the hardware of the processing apparatus is composed of general-purpose parts such as DSP. Therefore, it is possible to realize an ultrasonic diagnostic image forming apparatus in which the processing contents and the hardware of the processing device are completely separated and can be separately developed in parallel.

Further, according to the fourth invention for solving the problem, since the processing for forming the diagnostic image is performed by frequency main, the hardware of the processing apparatus can be constituted by general-purpose parts such as DSP. It is possible to realize an ultrasonic diagnostic image forming apparatus in which the processing contents and the hardware of the processing apparatus are completely separated and can be separately developed in parallel.

According to the fifth aspect of the invention for solving the problems, the signals obtained by dividing the digitally converted echo reception signal into a plurality of sections on the time axis are converted into frequency signals by Fourier transform, and the frequency signals are converted into frequency signals. Since the processing for forming the diagnostic image is performed on the echo reception signal in the domain, the hardware of the processing device can be composed of general-purpose parts such as DSP, and the contents of the processing and the hardware of the processing device are completely separated. The effect that an ultrasonic diagnostic image forming apparatus having a dynamic focus function that can be separately developed in parallel can be realized is obtained.

Further, according to the sixth invention for solving the problem, the processing for forming the B-mode diagnostic image in the frequency domain by the Fourier transform of the digitally converted echo reception signal and the dynamic mode diagnostic image. Since the processing for forming
The hardware of the processing equipment can be composed of general-purpose parts such as DSP, the content of the processing and the hardware of the processing equipment can be completely separated and separately developed in parallel, and each processing of B mode and dynamic mode can be optimized. The effect that an ultrasonic diagnostic image forming apparatus that is easy to implement can be realized is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a flow of signal processing in the device according to the exemplary embodiment of the present invention.

FIG. 3 is a block diagram of a flow of convolution processing in the device according to the embodiment of the present invention.

[Explanation of symbols]

1 Ultrasonic probe 2 transceiver array 3 RF echo memory 4 DSP array 5 Coherent B / CFM memory 6 Display manager 7 Display

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) A61B 8/00-8/15

Claims (4)

(57) [Claims] 1. A transmitting / receiving unit for transmitting an ultrasonic wave to a subject to receive an echo thereof, a first converting unit for converting an echo reception signal obtained by the transmitting / receiving unit into a digital signal, and the first unit. Second conversion means for converting the echo reception signal digitally converted by the conversion means into a signal in the transform domain, and a beamforming and electronic focusing process for the echo reception signal in the transform domain and forming a diagnostic image. Ultrasonic wave comprising: a processing unit that performs processing for performing the processing; and a third conversion unit that reversely converts the signal processed by the processing unit from the transform domain signal to the real domain signal. Diagnostic image forming apparatus. 2. A transmitting / receiving unit for transmitting an ultrasonic wave to a subject and receiving an echo thereof, a first converting unit for converting an echo reception signal obtained by the transmitting / receiving unit into a digital signal, and the first unit. Second conversion means for converting the echo reception signal digitally converted by the conversion means into a frequency domain signal by Fourier transform, and beam forming and electronic focus processing for the echo reception signal in the frequency domain, and a diagnostic image It comprises: processing means for performing processing for forming; and third conversion means for inversely converting the signal processed by the processing means from the signal in the frequency domain into a signal in the real domain by inverse Fourier transform. And an ultrasonic diagnostic image forming apparatus. 3. A transmission / reception unit for transmitting an ultrasonic wave to a subject and receiving an echo thereof, a first conversion unit for converting an echo reception signal obtained by the transmission / reception unit into a digital signal, and the first conversion unit. Second conversion means for converting a signal obtained by digitally converting the echo reception signal digitally converted by the conversion means into a plurality of sections on the time axis into frequency domain signals by Fourier transform, and echo reception signals in the frequency domain. Processing means for performing processing for forming a diagnostic image, including processing of beam forming and electronic focusing, and inverse conversion of the signal processed by the processing means from the frequency domain signal to the real domain signal by inverse Fourier transform An ultrasonic diagnostic image forming apparatus, comprising: 4. A transmitting / receiving unit for transmitting an ultrasonic wave to a subject and receiving an echo thereof, a first converting unit for converting an echo reception signal obtained by the transmitting / receiving unit into a digital signal, and the first unit. Second conversion means for converting the echo reception signal digitally converted by the conversion means into a frequency domain signal by Fourier transform; and beam forming and electronic focus processing for the echo reception signal in the frequency domain, and a B mode First to perform a process for forming a diagnostic image
The second processing means for performing beam forming and electronic focusing processing on the echo reception signal in the frequency domain, and performing processing for forming a dynamic mode diagnostic image, and the first processing means. Fourth transforming means for inversely transforming the processed signal from the signal in the frequency domain into a signal in the real domain by an inverse Fourier transform; and a signal processed by the second processing means in the frequency domain by an inverse Fourier transform. An ultrasonic diagnostic image forming apparatus comprising: a fifth conversion unit that reversely converts a signal into a signal in the real domain.