WO2021176618A1 - Ultrasound image generation device, ultrasound image generation device operating method, ultrasound image generation device operating program, and ultrasound image generation circuit - Google Patents

Ultrasound image generation device, ultrasound image generation device operating method, ultrasound image generation device operating program, and ultrasound image generation circuit Download PDF

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Publication number
WO2021176618A1
WO2021176618A1 PCT/JP2020/009262 JP2020009262W WO2021176618A1 WO 2021176618 A1 WO2021176618 A1 WO 2021176618A1 JP 2020009262 W JP2020009262 W JP 2020009262W WO 2021176618 A1 WO2021176618 A1 WO 2021176618A1
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ultrasonic
data
spectrum data
frequency
frequency spectrum
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PCT/JP2020/009262
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French (fr)
Japanese (ja)
Inventor
川島　知直
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オリンパス株式会社
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Priority to PCT/JP2020/009262 priority Critical patent/WO2021176618A1/en
Publication of WO2021176618A1 publication Critical patent/WO2021176618A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters

Definitions

  • the present invention relates to an ultrasonic image generator for observing tissues such as patients and animals as a subject using ultrasonic waves, an operation method of the ultrasonic image generator, an operation program of the ultrasonic image generator, and an ultrasonic image generation circuit. Regarding.
  • an ultrasonic echo echoed backward by the observation target is received by an ultrasonic vibrator and converted into an ultrasonic signal, and the converted ultrasonic signal is used.
  • a technique of calculating a feature amount from a frequency spectrum and imaging the calculated feature amount is known (see, for example, Patent Document 1).
  • Scattering of sound waves is a physical phenomenon in which sound waves can change their traveling direction by colliding with particles in a medium and exerting forces on each other (this is called interaction).
  • backscattering is a phenomenon or a component thereof that returns to the direction of the sound source in the scattering.
  • the sound source at this time is an ultrasonic vibrator.
  • the feature amount of the frequency spectrum is extracted as an analysis value representing the texture of the observation target.
  • a feature amount image to which visual information corresponding to this feature amount, for example, color information is added is generated.
  • the feature amount image is superimposed on the ultrasonic image based on the ultrasonic signal, and the superimposed image is generated and displayed.
  • a surgeon such as a doctor can diagnose the tissue properties of the observation target by looking at the displayed superimposed image.
  • Patent Document 1 a frequency band for calculating a feature amount is set for each frequency spectrum, and the feature amount is calculated from an ultrasonic signal in the set frequency band. According to Patent Document 1, the accuracy of the feature amount is improved by setting the frequency band individually.
  • Patent Document 2 uses a small-diameter ultrasonic probe provided with an ultrasonic transmitter / receiver for transmitting / receiving ultrasonic waves having different frequency characteristics, and receives a signal from each ultrasonic transmitter / receiver from the ultrasonic transmitter / receiver.
  • An ultrasonic image is generated by weighting according to the depth.
  • Patent Document 2 composites and displays a plurality of ultrasonic images having different frequency characteristics as smooth images on the same image.
  • the ultrasonic transducer to be arranged must be made smaller.
  • the frequency band cannot be widened, and the calculation accuracy of the feature amount may decrease.
  • the high-frequency component of the ultrasonic wave is attenuated, and the effective band of the originally narrow spectrum is further narrowed. Therefore, the feature amount calculation accuracy is significantly reduced.
  • the effective band is a frequency component having a level higher than the noise level in the frequency band.
  • Patent Document 1 since the frequency band for calculating the feature amount is changed to another effective band with respect to the frequency spectrum already obtained, the feature amount can be calculated with high accuracy in the changed effective band.
  • the bandwidth is originally narrow even if all the effective bands are combined, and it is difficult to change the bandwidth. Therefore, it is necessary to devise a method for further improving the accuracy of feature calculation.
  • the reception intensity of the image based on the ultrasonic signal for example, the ultrasonic echo is measured.
  • the resolution of the B-mode image expressed in terms of brightness, also decreases.
  • the present invention has been made in view of the above, and is an ultrasonic image generator, an ultrasonic image generator capable of obtaining an image based on an ultrasonic signal and expressing the properties of a tissue with high accuracy. It is an object of the present invention to provide an operation method of an apparatus, an operation program of an ultrasonic image generator, and an ultrasonic image generation circuit.
  • the ultrasonic image generator has frequency characteristics different from those of the first ultrasonic signal and the first ultrasonic signal from the ultrasonic echo.
  • a first frequency analysis unit that generates first frequency spectrum data for the first ultrasonic signal and the first frequency analysis unit.
  • a second frequency analysis unit that generates a second frequency spectrum data for the ultrasonic signal of 2
  • a synthesis unit that synthesizes the first frequency spectrum data and the second frequency spectrum data to generate a composite spectrum data. It is characterized by including a display image data generation unit that generates display image data to be displayed on the display device based on the composite spectrum data.
  • the ultrasonic image generator generates a feature amount calculation unit that calculates a feature amount based on the composite spectrum data, and a feature amount image data to which color information is added according to the feature amount. It is characterized by further including a feature amount image data generation unit.
  • the ultrasonic image generator according to the present invention is characterized in that, in the above invention, the feature amount calculation unit calculates the feature amount based on a regression line calculated from the composite spectrum data.
  • the ultrasonic image generator uses at least one of the first ultrasonic signal and the second ultrasonic signal to generate B-mode image data. It is characterized by further providing a part.
  • the synthesis unit adds the first frequency spectrum data of the linear representation and the second frequency spectrum data of the linear representation to the composite spectrum. It is characterized by generating data.
  • the ultrasonic image generator uses at least one of the first ultrasonic signal and the second ultrasonic signal to generate B-mode image data.
  • the image data generation unit further comprises a unit, and the image data generation unit associates the coordinates of the feature amount image data with the coordinates of the B mode image data, and provides color information according to the feature amount on the B mode image data. It is characterized by being placed in.
  • the ultrasonic image generator according to the present invention is characterized in that, in the above invention, the B-mode image data generation unit generates the B-mode image data using the synthetic spectrum data.
  • the ultrasonic image generator according to the present invention is characterized in that, in the above invention, further includes a position correction unit for correcting the acquisition position of the first frequency spectrum data and the second frequency spectrum data.
  • the B mode image data generation unit mixes the first frequency spectrum data and the second frequency spectrum data according to a set mixing ratio.
  • the B-mode image data is generated by mixing the data.
  • the display image data generation unit converts the feature amount image data into the B mode image data according to a set superposition ratio of the feature amount image data. It is characterized by superimposing.
  • the ultrasonic image generator according to the present invention is characterized in that, in the above invention, further includes a log amplifier for logarithmically transforming the synthesized spectrum data.
  • the operating method of the ultrasonic image generator receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo.
  • a method of operating an ultrasonic image generator that generates an ultrasonic image, in which a first frequency analysis unit generates first frequency spectrum data for the first ultrasonic signal, and a second frequency analysis unit generates first frequency spectrum data.
  • the second frequency spectrum data is generated for the second ultrasonic signal, and the synthesizer synthesizes the first frequency spectrum data and the second frequency spectrum data to generate the composite spectrum data, and the image
  • the data generation unit is characterized in that the display image data to be displayed on the display device is generated based on the composite spectrum data.
  • the operation program of the ultrasonic image generator receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo.
  • An operation program executed by an ultrasonic image generator that generates an ultrasonic image, which generates first frequency spectrum data for the first ultrasonic signal and a second frequency for the second ultrasonic signal.
  • Spectral data is generated, the first frequency spectrum data and the second frequency spectrum data are combined to generate synthetic spectrum data, and based on the synthetic spectrum data, display image data to be displayed on a display device is generated. It is characterized by generating.
  • the ultrasonic image generation circuit receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo, and receives the first ultrasonic signal.
  • a first frequency spectrum data is generated for the ultrasonic signal of the above, a second frequency spectrum data is generated for the second ultrasonic signal, and the first frequency spectrum data and the second frequency spectrum data are combined. It is characterized in that a process of generating synthetic spectrum data by synthesizing and generating display image data to be displayed on a display device based on the synthetic spectrum data is executed.
  • FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a first embodiment of the present invention.
  • FIG. 2 is a diagram illustrating a configuration of an ultrasonic vibrator in an ultrasonic probe.
  • FIG. 3 is a diagram schematically showing the scanning region of the ultrasonic vibrator and the sound line data.
  • FIG. 4 is a diagram schematically showing a data arrangement in RF data on one sound line of an ultrasonic signal.
  • FIG. 5 is a diagram illustrating spectrum data used in the ultrasonic observation device according to the first embodiment of the present invention.
  • FIG. 6A is a diagram (No. 1) for explaining the calculation of the frequency feature amount using the frequency spectrum.
  • FIG. 6B is a diagram (No.
  • FIG. 7 is a flowchart showing an outline of the processing performed by the ultrasonic observation apparatus according to the first embodiment of the present invention.
  • FIG. 8 is a flowchart showing an outline of the processing executed by the frequency analysis unit of the ultrasonic observation apparatus according to the first embodiment of the present invention.
  • FIG. 9 is a diagram showing a display example of an image based on an ultrasonic signal.
  • FIG. 10 is a diagram (No. 1) for explaining the setting of the position correction data stored in the ultrasonic probe.
  • FIG. 11 is a diagram (No.
  • FIG. 12 is a diagram (No. 3) for explaining the setting of the position correction data stored in the ultrasonic probe.
  • FIG. 13 is a diagram illustrating a configuration of a main part of the ultrasonic probe according to the second embodiment of the present invention.
  • FIG. 14 is a diagram illustrating a configuration of a main part of an ultrasonic probe according to a modified example of the second embodiment of the present invention.
  • FIG. 15 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a third embodiment of the present invention.
  • FIG. 16 is a flowchart showing an outline of processing performed by the ultrasonic observation apparatus according to the third embodiment of the present invention.
  • FIG. 17 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a fourth embodiment of the present invention.
  • FIG. 18 is a flowchart showing an outline of the processing performed by the ultrasonic observation apparatus according to the fourth embodiment of the present invention.
  • FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic system 1 provided with an ultrasonic observation device 3 according to a first embodiment of the present invention.
  • the ultrasonic diagnostic system 1 shown in the figure is an ultrasonic probe 2 that transmits ultrasonic waves to a subject and receives ultrasonic waves back-scattered by the subject, and an ultrasonic probe 2 acquired by the connected ultrasonic probe 2.
  • An ultrasonic observation device 3 that generates an ultrasonic image based on an ultrasonic signal, a display device 4 that displays an ultrasonic image generated by the ultrasonic observation device 3, and a control panel 5 that inputs various information related to the generation of image data.
  • a control panel 5 that inputs various information related to the generation of image data.
  • an intraluminal ultrasonic probe is used as the ultrasonic probe 2.
  • the solid line arrow indicates the transmission of electrical signals related to the frequency spectrum and feature quantities
  • the dotted line arrow indicates the transmission of electrical signals and data related to the B-mode image
  • the single-point chain line arrow indicates control and others.
  • the transmission of electrical signals and data is indicated
  • the double-lined arrows indicate the transmission of electrical signals and data related to the image finally displayed on the display device 4.
  • the circuit configuration of the ultrasonic transmission system has been omitted for convenience of explanation.
  • the ultrasonic probe 2 is an example of a small-diameter ultrasonic probe, and has a flexible insertion portion 21 inserted into a subject and an operation portion 22 connected to the proximal end side of the insertion portion 21. ..
  • the electrical pulse signal received from the ultrasonic observation device 3 is converted into an ultrasonic pulse (acoustic pulse) and irradiated to the subject, and the subject is backscattered by the subject.
  • It has an ultrasonic transducer (first ultrasonic transducer 211 and second ultrasonic transducer 212) that converts an ultrasonic echo into an electrical echo signal expressed by a voltage change (see FIG. 2).
  • FIG. 2 is a diagram illustrating a configuration of an ultrasonic vibrator in an ultrasonic probe.
  • the insertion portion 21 has two ultrasonic vibrators (first ultrasonic vibrator 211 and second ultrasonic vibrator 212) and a backing material 213 provided between the ultrasonic vibrators at one end thereof. It has a flexible flexible shaft 214 which is connected to the backing material 213 and the other end extends toward the operation portion 22 side.
  • the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 are ultrasonic vibrators that transmit ultrasonic beams having different frequency characteristics from each other. Each ultrasonic transducer transmits ultrasonic beams E 1 and E 2 on the scanning surface, respectively, and receives the ultrasonic waves returned by backscattering.
  • the first ultrasonic transducer 211 and the second ultrasonic transducer 212 are each scanned scanning plane P S, receives the come ultrasound back through the scanning plane P S.
  • the scanning plane P S shown in FIG. 2 is represented by a rectangle corresponding to the display screen of the display device 4.
  • the frequency of the ultrasonic beam E 1 transmitted by the first ultrasonic vibrator 211 is higher than the frequency of the ultrasonic beam E 2 transmitted by the second ultrasonic vibrator 212. That is, in the first embodiment, the first ultrasonic vibrator 211 is a high frequency type ultrasonic vibrator, and the second ultrasonic vibrator 212 is a low frequency type ultrasonic vibrator.
  • the ultrasonic vibrator is configured by using a piezoelectric element.
  • the backing material 213 is a member that attenuates unnecessary ultrasonic vibration generated by the operation of the piezoelectric element. Specifically, the backing material 213 attenuates unnecessary ultrasonic vibrations generated by the operation of the piezoelectric elements of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212. The backing material 213 can suppress the propagation of unnecessary ultrasonic vibration from one ultrasonic vibrator to the other ultrasonic vibrator.
  • the backing material 13 is formed by using a material having a large damping rate.
  • the flexible shaft 214 is constructed using a flexible material.
  • the flexible shaft 214 rotates about an axis extending in the longitudinal direction under the control of, for example, the ultrasonic observation device 3.
  • the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 also rotate.
  • the rotation of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 changes the positions of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 in the circumferential direction of the tip of the insertion portion 21.
  • NS A high-frequency signal line connected to the first ultrasonic vibrator 211 and a low-frequency signal line connected to the second ultrasonic vibrator 212 are inserted into the flexible shaft 214.
  • the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 transmit a signal to the ultrasonic observation device 3 via each signal line.
  • the operation unit 22 is gripped by an operator such as a doctor.
  • the operation unit 22 has a storage unit 221 inside.
  • the storage unit 221 stores the position correction data for correcting the positional relationship of each ultrasonic vibrator with respect to the positional relationship of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212.
  • the ultrasonic observation device 3 includes a connection unit 300, a first A / D converter 301, a second A / D converter 302, a first frequency analysis unit 303, a second frequency analysis unit 304, a buffer 305, 306, 314, and a synthesis unit 307.
  • 1st log amplifier 308, feature amount calculation unit 309, 1st coordinate conversion unit 310, mixing unit 311, 2nd log amplifier 312, envelope detection unit 313, 2nd coordinate conversion unit 315, superimposition unit 316, display image signal generation A unit 317 and a storage unit 318 are provided.
  • the ultrasonic observation device 3 corresponds to an ultrasonic image generator.
  • the connection portion 300 has a high-frequency connection pin 300a for connecting to the high-frequency signal line and a low-frequency connection pin 300b for connecting to the low-frequency signal line, and is fixed to the housing of the ultrasonic observation device 3. ..
  • the operation unit 22 is removable from the connection unit 300. That is, the operation unit 22 is removable from the ultrasonic observation device 3.
  • the connection unit 300 electrically connects the ultrasonic probe 2 and the ultrasonic observation device 3 via the high-frequency signal line and the low-frequency signal line.
  • the first A / D converter 301 receives an echo signal, which is an electric radio frequency (RF: Radio Frequency) signal, from the ultrasonic probe 2 via a high frequency signal line, and converts it into an echo signal by A / D. It is processed to generate and output digital data (hereinafter referred to as RF data).
  • RF radio frequency
  • the second A / D converter 302 receives an electrical echo signal from the ultrasonic probe 2 via a low-frequency signal line, performs A / D conversion processing on the echo signal, and generates and outputs RF data. ..
  • the first A / D converter 301 and the second A / D converter 302 first amplify the received echo signal.
  • the first A / D converter 301 and the second A / D converter 302 perform processing such as filtering on the amplified echo signal, and then sample at an appropriate sampling frequency (for example, 50 MHz) and discretize (so-called A / D). Conversion processing).
  • the first A / D converter 301 and the second A / D converter 302 generate discretized RF data from the amplified echo signal.
  • the first A / D converter 301 outputs RF data to the first frequency analysis unit 303 and the mixing unit 311.
  • the second A / D converter 302 outputs RF data to the second frequency analysis unit 304 and the mixing unit 311.
  • the ultrasonic observation device 3 is electrically connected to the ultrasonic probe 2 and transmits a transmission signal (pulse signal) composed of a high voltage pulse based on a predetermined waveform and transmission timing to the ultrasonic vibrator.
  • a transmission signal pulse signal
  • Two circuits are provided.
  • One of the transmission circuits is connected to the first ultrasonic transducer 211.
  • the frequency band of the pulse signal to be transmitted substantially covers the linear response frequency band of the first ultrasonic vibrator 211 when the first ultrasonic vibrator 211 converts the pulse signal into an ultrasonic pulse. Make it wideband.
  • another one of the transmission circuits is connected to the second ultrasonic vibrator 212.
  • the frequency band of the pulse signal to be transmitted substantially covers the linear response frequency band of the second ultrasonic vibrator 212 when the second ultrasonic vibrator 212 converts the pulse signal into an ultrasonic pulse. Make it wideband.
  • the various processing frequency bands of the echo signal in the first A / D converter 301 and the second A / D converter 302 are the linear shape of the ultrasonic transducer when the ultrasonic transducer acoustically converts the ultrasonic echo into an echo signal. Make the wide band almost cover the response frequency band. As a result, it is possible to perform an accurate approximation when executing the frequency spectrum approximation processing described later.
  • the first frequency analysis unit 303 performs frequency analysis by performing a fast Fourier transform (FFT) on the RF data generated by the first A / D converter 301 to perform frequency spectrum data (hereinafter, first spectrum data). ) Is calculated. Specifically, the first frequency analysis unit 303 divides the RF data (line data) of each sound line generated by the first A / D converter 301 into a plurality of pieces at relatively short predetermined time intervals, and divides each part. By applying FFT processing to RF data (hereinafter referred to as "RF data string”), the frequency spectrum in each part of the sound line is calculated.
  • the "frequency spectrum” here means the frequency distribution of the intensity and voltage amplitude of the echo signal obtained from the "certain reception depth z (that is, a certain round-trip distance L)" obtained by subjecting the RF data string to FFT processing. Means.
  • the case where the frequency distribution of the voltage amplitude of the echo signal is adopted as the frequency spectrum will be described.
  • the case where the first frequency analysis unit 303 generates the data of the first spectrum based on the frequency component V (f) of the voltage amplitude will be described as an example.
  • f is a frequency.
  • the first frequency analysis unit 303 divides the frequency component V (f) of the amplitude of the RF data (in effect, the voltage amplitude of the echo signal) by the reference voltage V c , takes the common logarithm (log), and expresses it in decibel units.
  • the first spectrum data S (f) of the subject given by the following equation (1) is generated by multiplying by an appropriate positive constant ⁇ .
  • the frequency spectrum of the echo signal tends to differ depending on the properties of the human tissue scanned by the ultrasonic waves. This is because the frequency spectrum has a correlation with the size, number density, acoustic impedance, etc. of the scatterer that scatters ultrasonic waves.
  • the "characteristics of human tissue” here refers to the characteristics of tissues such as malignant tumors (cancers), benign tumors, endocrine tumors, mucinous tumors, normal tissues, cysts, and vessels.
  • FIG. 3 is a diagram schematically showing a scanning region (hereinafter, may be simply referred to as a scanning region) of the ultrasonic vibrator and sound line data.
  • the scanning area S shown in FIG. 3 has a circular shape.
  • the ultrasonic transducer expresses the path (sound line) through which the ultrasonic waves reciprocate as a straight line, and the sound line data as points arranged on each sound line.
  • each sound line is numbered 1, 2, 3, ... In order from the start of scanning (right in FIG. 3), and the first sound line is SR 1 , 2.
  • the third sound line is defined as SR 2
  • the third sound line is defined as SR 3
  • ...
  • the kth sound line is defined as SR k.
  • the reception depth of the sound line data is described as z.
  • FIG. 4 is a diagram schematically showing a data arrangement in RF data on one sound line SR k of an ultrasonic signal.
  • the white or black rectangle on the sound line SR k means the data at one sample point.
  • the data located on the right side is the RF data from the deeper part when measured from the ultrasonic transducer along the sound line SR k (see the arrow in FIG. 4). ).
  • the RF data on the sound line SR k is the RF data sampled from the echo signal by the A / D conversion process in the A / D converter and discretized.
  • FIG. 4 there is shown a case of setting the initial value Z (k) 0 in the direction of the eighth data position reception depth z of the RF data on sound ray SR k of number k, the position of the initial value It can be set arbitrarily.
  • the calculation result by the first frequency analysis unit 303 is stored in the storage unit 318.
  • the maximum value Z (k) max of the data position is a data position representing the deepest RF data string in the analysis range on the sound line SR k. This maximum value k max is the number of the leftmost sound line in the analysis range in FIG.
  • the RF data string needs to have a power of 2 data number.
  • the RF data string F K is an abnormal RF data string because the number of data is 12.
  • the first frequency analysis unit 303 executes the FFT process as described above, calculates the frequency component V (f) of the voltage amplitude, and obtains the first spectrum data S (f) based on the above equation (1). ) Is calculated.
  • the first frequency analysis unit 303 changes the data position Z (k) with the step width D to calculate the first spectrum data S (f) at each position.
  • the first frequency analysis unit 303 further repeats this action on all the sound lines shown in FIG. 3, calculates the first spectrum data S (f) in all directions, and outputs the first spectrum data S (f) to the buffer 305. (Hereinafter, the "direction" will be described as an ultrasonic transmission / reception direction over all scanning directions in FIG. 3).
  • the second frequency analysis unit 304 described above performs frequency analysis by applying FFT to the RF data generated by the second A / D converter 302 in the same manner as the first frequency analysis unit 303, thereby performing frequency spectrum data. (Hereinafter referred to as second spectrum data) is calculated.
  • the buffer 305 temporarily stores the first spectrum data input from the first frequency analysis unit 303 and outputs it to the synthesis unit 307.
  • the buffer 306 temporarily stores the second spectrum data input from the second frequency analysis unit 304 and outputs it to the synthesis unit 307.
  • the synthesis unit 307 synthesizes the first spectrum data and the second spectrum data.
  • the synthesis unit 307 includes a position correction unit 307a for correcting the positions of the first spectrum data and the second spectrum data on the subject.
  • the position correction unit 307a corrects the positional deviation caused by the rotation angle of the flexible shaft 214 between the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 based on the position correction data acquired from the ultrasonic probe 2. do.
  • the synthesizing unit 307 synthesizes the first spectrum data and the second spectrum data whose position has been corrected by the position correction unit 307a. Specifically, the synthesis unit 307 adds the linear representations of the first and second spectrum data after the position correction.
  • the first log amplifier 308 performs logarithmic conversion on the input voltage amplitude and outputs the converted voltage amplitude.
  • logarithmic conversion data representing the amplitude or intensity of an echo signal is divided by a specific voltage V c called a reference voltage, and the common logarithm is taken for conversion.
  • the converted data is represented by a decibel value (see equation (1)).
  • values proportional to the digit of the amplitude or intensity of the echo signal indicating the intensity of backward scattering of the ultrasonic pulse expressed in decimal numbers are arranged along the transmission / reception direction (depth direction) of the ultrasonic pulse. It is data.
  • FIG. 5 is a diagram illustrating spectrum data used in the ultrasonic observation device according to the first embodiment of the present invention.
  • the combination unit 307 outputs the data.
  • the linear representation of the composite spectral data to be obtained is represented by V HO (f) + V LO (f).
  • the synthetic spectrum data that has passed through the first log amplifier 308 is represented by 20 log ⁇ (V HO (f) + V LO (f)) / V c ⁇ as a db representation.
  • the linear representation of the spectral data represents the frequency distribution of the amplitude of the received signal
  • the dB representation represents the signal level of the frequency distribution of the linear representation.
  • the feature amount calculation unit 309 approximates the composite spectrum data output from the first log amplifier 308 with a straight line, and calculates the feature amount of the spectrum data using the straight line.
  • the feature amount calculation unit 309 outputs the feature amount to the first coordinate conversion unit 310.
  • the feature amount calculation unit 309 performs a simple regression analysis of the composite spectrum data in a predetermined frequency band and approximates the composite spectrum data with a linear equation (regression line) to characterize the approximated linear equation. Calculate the amount.
  • the simple regression analysis is a regression analysis when there is only one type of independent variable.
  • the independent variable of the simple regression analysis in this embodiment corresponds to the frequency f.
  • 6A to 6C are diagrams for explaining the calculation of the frequency feature amount using the frequency spectrum.
  • the feature amount calculation unit 309 performs a simple regression analysis in the frequency band U to obtain a regression line L S of the composite spectrum data S S (see FIG. 6A).
  • the feature amount calculating unit 309, the gradient a 1 of the regression line L S, the center frequency (i.e., "mid band") of the intercept b 1, and the frequency band U f M the (f L + f H) / 2
  • the midband fit c 1 provides the voltage amplitude and intensity of the echo signal at the center of the valid frequency band. Therefore, it is considered that the mid-band fit c 1 has a certain degree of correlation with the brightness of the B-mode image in addition to the size of the scatterer, the scattering intensity of the scatterer, and the number density of the scatterer.
  • the feature amount calculation unit 309 may approximate the frequency spectrum data with a polynomial of degree 2 or higher by regression analysis.
  • the first frequency analysis unit 303, the second frequency analysis unit 304, the feature amount calculation unit 309, and the first coordinate conversion unit 310 process the entire scanning region S as the analysis range.
  • the analysis range is limited to the region of interest (Region of Interest: ROI) divided by a specific depth width and azimuth width (that is, the width in the scanning direction) in the scanning area S shown in FIG. Each process may be performed.
  • ROI region of interest
  • azimuth width that is, the width in the scanning direction
  • the mixing unit 311 mixes RF data input from the first A / D converter 301 and the second A / D converter 302, respectively, based on the mixing ratio data input from the control panel 5.
  • the mixing unit 311 outputs the mixed RF data to the second log amplifier 312.
  • the second log amplifier 312 performs logarithmic conversion on the input voltage amplitude in the same manner as the first log amplifier 308, and outputs the converted voltage amplitude.
  • the envelope detection unit 313 applies a bandpass filter and an envelope detection to the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
  • the second coordinate conversion unit 315 performs coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly, and then performs interpolation processing between the sound line data to produce sound.
  • B-mode image data is generated by filling the gaps between the line data.
  • the B-mode image is a grayscale image in which the values of R (red), G (green), and B (blue), which are variables when the RGB color system is adopted as the color space, are matched.
  • the second coordinate conversion unit 315 outputs the generated B-mode image data to the superimposition unit 316.
  • the second coordinate conversion unit 315 may perform STC (Sensitivity Time Control) correction that amplifies RF data having a larger reception depth with a higher amplification factor. Further, the second coordinate conversion unit 315 may perform signal processing on the sound line data using known techniques such as gain processing and contrast processing.
  • the superimposition unit 316 superimposes the feature amount image data generated by the first coordinate conversion unit 310 on the B mode image data generated by the second coordinate conversion unit 315, and generates display image data to be displayed on the display device 4. do.
  • the superimposition unit 316 superimposes the feature amount image data on the B mode image data by adjusting the brightness of the B mode image and the brightness of the feature amount based on the superimposition ratio data input from the control panel 5. ..
  • the superimposing unit 316 corresponds to a display image data generation unit.
  • the display image signal generation unit 317 arranges an image corresponding to the display image data (superimposed image described later) at a predetermined position on the display screen, thins out the data according to the display range of the image on the display device 4, and performs the data thinning.
  • a display image signal to be displayed on the display device 4 is generated by performing a predetermined process such as a gradation process.
  • the display image signal generation unit 317 outputs the generated display image signal to the display device 4 for display.
  • the storage unit 318 stores calculation parameters, data, etc. of each process.
  • the storage unit 318 acquires and stores position correction data from the connected ultrasonic probe 2.
  • the storage unit 318 may store the generated B-mode image data, frequency spectrum data, feature amount image data, and the like.
  • the frequency spectrum data includes at least one of the first spectrum data, the second spectrum data, and the composite spectrum data.
  • the storage unit 318 is configured by using, for example, an HDD (Hard Disk Drive) or an SDRAM (Synchronous Dynamic Random Access Memory).
  • the storage unit 318 includes, for example, information required for various processes, information required for logarithmic conversion processing (see equation (1), for example, values of ⁇ and V c ), and a window required for frequency analysis processing. Stores information such as functions (Hamming, Hanning, Blackman, etc.).
  • the storage unit 318 is a non-temporary computer-readable recording medium in which an operation program for executing the operation method of the ultrasonic observation device 3 is pre-installed, for example, a ROM (Read Only Memory) (not shown). ) Is provided.
  • the operation program can also be recorded on a computer-readable recording medium such as a portable hard disk, flash memory, CD-ROM, DVD-ROM, or flexible disk and widely distributed.
  • the various programs described above can also be acquired by downloading them via a communication network.
  • the communication network referred to here is realized by, for example, an existing public line network, LAN, WAN, etc., and may be wired or wireless.
  • the ultrasonic observation device 3 reads information such as an operation program stored and stored in the storage unit 318, calculation parameters of each process, data, etc. from the storage unit 318, and causes each unit to execute various calculation processes related to the operation method. As a result, the ultrasonic observation device 3 is controlled in an integrated manner.
  • the display image signal generation unit 317 is dedicated to executing a general-purpose processor such as a CPU (Central Processing Unit) having arithmetic and control functions, or a specific function such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). It is realized by using the integrated circuit of. It is also possible to configure a plurality of parts including at least a part of the above by using a common general-purpose processor, a dedicated integrated circuit, or the like.
  • a general-purpose processor such as a CPU (Central Processing Unit) having arithmetic and control functions, or a specific function such as an ASIC (Application
  • the control panel 5 is configured by using a plurality of buttons capable of inputting various information, and accepts input from the operator.
  • the control panel 5 is provided with a first knob 51 and a second knob 52.
  • Each of the first knob 51 and the second knob 52 is rotatable and outputs an operation signal according to the rotation position.
  • the first knob 51 inputs the mixing ratio of RF data in the mixing unit 311.
  • the ratio (H: L) of the RF data (H) from the first A / D converter 301 to the RF data (L) from the second A / D converter 302 is set according to the rotation position of the first knob 51.
  • H: L is set to 100: 0, 0: 100, 50:50, 70:30, ..., Depending on the ratio that can be mixed.
  • the second knob 52 inputs the superposition ratio of the feature amount image data in the superimposition unit 316.
  • the ratio (A: B) of the feature amount image data (A) from the first coordinate conversion unit 310 to the B mode image data (B) from the second coordinate conversion unit 315. ) Is set.
  • A: B 100: 0, 0: 100, 50:50, 70:30, ... are set according to the ratio that can be superimposed.
  • the control panel 5 may be further provided with a touch panel provided with a display screen.
  • the touch panel functions as a graphical user interface (GUI) by displaying ultrasonic images and various information.
  • GUI graphical user interface
  • the touch panel includes a resistive film method, a capacitance method, an optical method, and the like, and any type of touch panel can be applied.
  • FIG. 7 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3 having the above configuration.
  • the ultrasonic observation device 3 acquires position correction data from the ultrasonic probe 2 (step S101). Further, in this process, it is assumed that various ratio data are input from the first knob 51 and the second knob 52.
  • step S102 when the observation of the subject such as the tissue inside the human body is started, the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 scan the subject and electrically transmit the echo received from the subject. Convert to echo signal.
  • the first A / D converter 301 receives an echo signal via the first ultrasonic vibrator 211.
  • the second A / D converter 302 receives the echo signal via the second ultrasonic transducer 212.
  • Each A / D converter amplifies the echo signal as needed, samples the amplified echo signal at an appropriate sampling frequency (for example, 50 MHz), and disperses it to generate RF data.
  • the first A / D converter 301 outputs the generated RF data to the first frequency analysis unit 303.
  • the second A / D converter 302 outputs the generated RF data to the second frequency analysis unit 304.
  • Steps S103 to S107 are the flow of the feature amount image data generation process.
  • the first frequency analysis unit 303 and the second frequency analysis unit 304 calculate frequency spectrum data from the RF data generated in step S102, respectively.
  • the first frequency analysis unit 303 divides the RF data (line data) of each sound line into a plurality of pieces at relatively short predetermined time intervals, and performs frequency analysis by FFT calculation on the RF data of each divided part. Calculate the frequency spectrum data for the RF data string.
  • FIG. 8 is a flowchart showing an outline of the processing executed by the first frequency analysis unit 303 and the second frequency analysis unit 304 in step S103.
  • the frequency analysis process will be described in detail with reference to the flowchart shown in FIG. It should be noted that this process is a flow based on the process described in FIG. In the following description, the frequency analysis process performed by the first frequency analysis unit 303 will be described, but the same applies to the second frequency analysis unit 304.
  • step S201 the first frequency analysis unit 303 sets the counter k for identifying the sound line to be analyzed as k 0 .
  • This initial value k 0 is the number of the rightmost sound line in the analysis range in FIG.
  • step S202 the first frequency analysis unit 303 sets the initial value Z (k) 0 of the data position (corresponding to the reception depth) Z (k) representing a series of RF data strings acquired for the FFT calculation.
  • the first frequency analysis unit 303 acquires the RF data string (step S203), and causes the window function stored by the storage unit 318 to act on the acquired RF data string (step S204).
  • the window function stored by the storage unit 318 By acting a window function on the RF data string, it is possible to prevent the RF data string from becoming discontinuous at the boundary and prevent the occurrence of artifacts.
  • the first frequency analysis unit 303 determines whether or not the RF data string at the data position Z (k) is a normal RF data string (step S205).
  • the number of data in the normal RF data string is 2 n (n is a positive integer).
  • step S205 when the RF data string at the data position Z (k) is normal (step S205: Yes), the first frequency analysis unit 303 shifts to step S207 described later.
  • step S205 when the RF data string at the data position Z (k) is not normal (step S205: No), the first frequency analysis unit 303 inserts zero data for the shortage to obtain normal RF data. Generate a string (step S206). After step S206, the first frequency analysis unit 303 shifts to step S207, which will be described later.
  • step S207 the first frequency analysis unit 303 calculates V (f) corresponding to the frequency distribution of the voltage amplitude of the echo signal by performing an FFT calculation on the RF data string. After that, the first frequency analysis unit 303 performs logarithmic conversion processing on V (f) to obtain frequency spectrum data S (f) (step S207).
  • step S208 the first frequency analysis unit 303 changes the data position Z (k) with the step width D.
  • the first frequency analysis unit 303 determines whether or not the data position Z (k) is larger than the maximum value Z (k) max in the sound line SR k (step S209).
  • the first frequency analysis unit 303 increments the counter k by 1 (step S210). This means that the processing is transferred to the next sound line.
  • the first frequency analysis unit 303 returns to step S203.
  • the first frequency analysis unit 303 determines whether or not the counter k is larger than the maximum value k max (step S211). When the counter k is larger than k max (step S211: Yes), the first frequency analysis unit 303 ends a series of frequency analysis processes. On the other hand, when the counter k is k max or less (step S211: No), the first frequency analysis unit 303 returns to step S202.
  • the first frequency analysis unit 303 performs a plurality of FFT calculations for each of the (k max ⁇ k 0 + 1) sound lines in the analysis target region for each depth.
  • the result of the FFT calculation is stored in the storage unit 318 together with the reception depth and the reception direction.
  • k 0 , k max , Z (k) 0 , and Z (k) max default values including the entire scanning range of FIG. 3 are stored in advance in the storage unit 318.
  • the first frequency analysis unit 303 appropriately reads these values and performs the processing of FIG. When the default value is read, the first frequency analysis unit 303 performs frequency analysis processing on the entire scanning range.
  • these four values, k 0 , k max , Z (k) 0 , and Z (k) max can be changed by inputting an instruction of the region of interest by the operator via the control panel 5. If it has been changed, the first frequency analysis unit 303 performs the frequency analysis process only in the region of interest in which the instruction is input.
  • step S104 the synthesis unit 307 synthesizes the first spectrum data and the second spectrum data. Specifically, the synthesis unit 307 is corrected by the position correction unit 307a to match the positions of the first spectrum data and the second spectrum data on the subject, and the position-corrected first spectrum data and the second spectrum data are present. Synthesize spectral data.
  • step S105 the first log amplifier 308 performs logarithmic conversion with respect to the input voltage amplitude.
  • the first log amplifier 308 outputs the converted voltage amplitude to the feature amount calculation unit 309.
  • the feature amount calculation unit 309 approximates the composite spectrum data output from the first log amplifier 308 with a straight line, and calculates the feature amount of the spectrum data using the straight line.
  • Feature amount calculation unit 309 for example, the gradient a 1 of the regression line L S described above, the intercept b 1, and of the mid-band fit c 1, calculates the specified characteristic quantity.
  • step S107 the first coordinate conversion unit 310 generates feature image data to which visual information is added according to the feature calculated by the feature calculation unit 309.
  • the mixing unit 311 mixes the RF data input from the first A / D converter 301 and the second A / D converter 302, respectively, based on the mixing ratio data input from the first knob 51. (Step S108).
  • step S108 to S111 are flows of B-mode image generation processing.
  • the second log amplifier 312 performs logarithmic conversion with respect to the input voltage amplitude in the same manner as the first log amplifier 308.
  • the second log amplifier 312 outputs the converted voltage amplitude to the envelope detection unit 313.
  • step S110 the envelope detection unit 313 performs envelope detection or the like on the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
  • step S111 the second coordinate conversion unit 315 performs coordinate conversion to rearrange the sound line data so that the generated sound line data can express the scanning range spatially correctly, and generates B mode image data.
  • the feature amount image data generation processing in steps S103 to S107 and the B-mode image generation processing in steps S108 to S111 may be performed at the same time, or one of them may be performed first.
  • step S112 the superimposition unit 316 superimposes the feature amount image data on the B mode image data based on the superimposition ratio data input from the second knob 52, and generates display image data to be displayed on the display device 4. do. Further, the superimposition unit 316 outputs the B mode image data to the display image signal generation unit 317.
  • step S113 the display image signal generation unit 317 thins out the display image data generated by the superimposition unit 316 and the B-mode image data according to the display range of the image in the display device 4, and performs gradation processing.
  • a display image signal is generated by performing a predetermined process such as, and is output to the display device 4 for display.
  • FIG. 9 shows a display example of an image corresponding to the display image data generated based on the ultrasonic signal.
  • the display screen W of the display device 4 a B-mode image W 1 to the feature amount image is not superimposed, the feature quantity image and superposed image W 2 superimposed is displayed on the B-mode image.
  • FIGS. 10 to 12 are views for explaining the setting of the position correction data stored in the ultrasonic probe 2.
  • the position correction data is acquired, for example, at the time of shipment of the ultrasonic probe 2 in the factory.
  • the position correction data is generated by acquiring an ultrasonic image (B mode image) of the Tegs 100 shown in FIG.
  • the echo signal causes the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 while rotating the flexible shaft 214 and simultaneously rotating and driving the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212. Scan to obtain each echo signal.
  • the first ultrasonic transducer 211 and the second ultrasonic transducer 212 to obtain the B-mode image including the image of the gut 100 at the scanning plane P S.
  • the ultrasonic probe 2 When setting the position correction data, the ultrasonic probe 2 is connected to the ultrasonic observation device 6 for a factory (see FIG. 11).
  • the ultrasonic observation device 6 generates a B-mode image based on the acquired echo signal.
  • the generated B-mode image is displayed on the monitor 61.
  • the image is displayed.
  • control panel 7 is connected to the ultrasonic observation device 6.
  • the control panel 7 is provided with a writing instruction button 71 for instructing writing of position correction data to the storage unit 221 and rotation instruction buttons 72 and 73 for inputting rotation instructions in opposite directions.
  • the B-mode image based on the first echo signal by the ultrasonic transducer 211 has acquired W BH, the gut image in the B-mode image W BH and Q H. Further, the B mode image based on the echo signal acquired by the second ultrasonic vibrator 212 is referred to as W BL , and the Tegs image in this B mode image W BL is referred to as Q L.
  • first ultrasonic transducer 211 and the second ultrasonic transducer 212 is bonded to the opposite side each other with respect to the backing material 213, in the B-mode superimposed image W BS, and guts image Q H and gut image Q L is positioned on the opposite side with respect to the center echo Q 0 (see B-mode superimposed image W BS in FIG. 11 for example).
  • the user in the B-mode superimposed image W BS, upon depression of the rotation instruction buttons 72 and 73, about the center echoes Q 0 by rotating the B-mode image W BH, to match the gut image Q H and gut image Q L (See FIG. 12).
  • the rotation angle ⁇ of the B mode image W BH when the Tegs image Q H and the Tegs image Q L match is set as the position correction data.
  • the ultrasonic observation device 6 uses the rotation angle at that time as position correction data for the ultrasonic probe 2. Write to the storage unit 221 of.
  • the feature amount is calculated using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal.
  • the feature amount calculation unit 309 can obtain a regression line in a sufficient frequency band. This makes it possible to calculate the feature amount more accurately than in the case of obtaining the regression line using only the high-frequency echo signal or only the low-frequency echo signal. According to the first embodiment, by calculating the feature amount with high accuracy, it becomes easy to distinguish a subtle difference between tissues.
  • the absolute value of the obtained feature amount is different between the first spectrum data S 1 and the second spectrum data S 2 and the synthetic spectrum data S S.
  • blue is often assigned as the reference color for normal tissues, and an appropriate color is often assigned to the relative value, which is the difference between the target tissue and the reference, rather than the absolute value. ..
  • the first ultrasonic vibrator 211 and the second ultrasonic transducer 211 are used. It is possible to correct the deviation that occurs when the ultrasonic vibrator 212 is attached to the backing material 213.
  • position correction unit 307a has been described as being provided in the synthesis unit 307 in the first embodiment, it may be provided separately from the composition unit 307.
  • the position correction data may be, for example, a deviation of the ultrasonic vibrator in the sound line direction from the central echo (distance (difference) from the flexible shaft 214).
  • FIG. 13 is a diagram illustrating a configuration of a main part of an ultrasonic endoscope according to a second embodiment of the present invention.
  • the second embodiment is different from the first embodiment described above in that the insertion portion 21 of the ultrasonic endoscope is configured.
  • the configuration of the insertion portion 21A of the ultrasonic endoscope according to the second embodiment will be described.
  • the insertion portion 21A converts an electrical pulse signal received from the ultrasonic observation device 3 into an ultrasonic pulse (acoustic pulse) and irradiates the subject with the tip portion thereof, and at the same time, the ultrasonic pulse is scattered backward by the subject. It has an ultrasonic vibrator 215 that converts an ultrasonic echo into an electrical echo signal expressed by a voltage change, an optical lens 216, and an image pickup element (not shown).
  • an ultrasonic endoscope is used as the ultrasonic probe.
  • the ultrasonic endoscope further has an optical lens for imaging and an image pickup element at the tip portion of the insertion portion 21A.
  • the ultrasonic vibrator 215 has a plurality of first vibrators 215a and a plurality of second vibrators 215b.
  • the first vibrator unit 215a and the second vibrator unit 215b are composed of piezoelectric elements that transmit ultrasonic beams having different frequency characteristics from each other.
  • the first vibrator portion 215a and the second vibrator portion 215b are alternately arranged in the circumferential direction of the insertion portion 21A. In FIG. 13, the second vibrator portion 215b is hatched to distinguish it from the first vibrator portion 215a.
  • the ultrasonic vibrator 215 is a radial type electronic ultrasonic vibrator in which the first vibrator portion 215a and the second vibrator portion 215b are alternately driven under the control of the ultrasonic observation device 3. For example, when acquiring a high-frequency echo signal, each first oscillator unit 215a is driven, and when acquiring a low-frequency echo signal, each second oscillator unit 215b is driven.
  • the received echo signal is output to the ultrasonic observation device 3 and processed in the same manner as in the first embodiment. Further, the image signal captured by the image sensor is output to an image processing device (not shown), and the captured image data is generated and displayed by an image processing circuit (not shown) in the image processing device.
  • the switching of the ultrasonic vibrator is different from each other in the ultrasonic probe (ultrasonic endoscope) which does not require a mechanical drive mechanism, as in the first embodiment.
  • the feature amount can be calculated accurately by using the high-frequency echo signal received from the ultrasonic vibrator having the frequency characteristics and the low-frequency echo signal. According to the second embodiment, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
  • FIG. 14 is a diagram illustrating a configuration of a main part of an ultrasonic probe according to a modified example of the second embodiment of the present invention.
  • the insertion portion 21B converts an electrical pulse signal received from the ultrasonic observation device 3 into an ultrasonic pulse (acoustic pulse) and irradiates the subject at the tip thereof, and at the same time, rearward the subject. It includes an ultrasonic vibrator 217 that converts scattered ultrasonic echoes into an electrical echo signal expressed by a voltage change, an optical lens 218, and an image pickup element (not shown).
  • the ultrasonic vibrator 217 has a plurality of first vibrators 217a and a plurality of second vibrators 217b.
  • the first vibrator unit 217a and the second vibrator unit 217b are composed of piezoelectric elements that transmit ultrasonic beams having different frequency characteristics from each other.
  • the first vibrator portion 217a and the second vibrator portion 217b are alternately arranged in the longitudinal direction of the insertion portion 21B to form a curved outer surface.
  • the second vibrator portion 217b is hatched to distinguish it from the first vibrator portion 217a.
  • the ultrasonic vibrator 217 is shown as an image of a model in which the thickness of the vibrator is emphasized for explanation, unlike the actual thickness of the vibrator and the structure in the thickness direction.
  • the ultrasonic vibrator 217 is a convex type electronic ultrasonic vibrator in which the first vibrator portion 217a and the second vibrator portion 217b are alternately driven under the control of the ultrasonic observation device 3. For example, when acquiring a high-frequency echo signal, each first oscillator unit 217a is driven, and when acquiring a low-frequency echo signal, each second oscillator unit 217b is driven. The received echo signal is output to the ultrasonic observation device 3 and processed in the same manner as in the first embodiment.
  • the feature amount is determined by using the high frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low frequency echo signal as in the first and second embodiments. Since it is calculated, the feature amount can be calculated accurately. According to this modified example, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
  • FIG. 15 is a block diagram showing a configuration of an ultrasonic diagnostic system 1A including the ultrasonic observation device 3A according to the third embodiment of the present invention.
  • the same configurations as those described in the first embodiment are designated by the same reference numerals and have the same functions as those described in the first embodiment.
  • the ultrasonic diagnostic system 1A includes an ultrasonic observation device 3A instead of the ultrasonic observation device 3 for the configuration of the ultrasonic diagnostic system 1 according to the first embodiment described above, and is a control panel.
  • a control panel 5A is provided instead of 5.
  • the third frequency analysis unit 319 performs an inverse FFT on the composite spectrum data from the synthesis unit 307.
  • the data generated by the processing of the third frequency analysis unit 319 corresponds to the composite data of the RF data whose composite spectrum data is output from the first A / D converter 301 and the second A / D converter 302.
  • the first log amplifier 320 performs logarithmic conversion on the input voltage amplitude in the same manner as the first log amplifier 308, and outputs the converted voltage amplitude.
  • the first envelope detection unit 321 applies a bandpass filter and an envelope detector to the data after passing through the first log amplifier 320, and generates digital sound line data representing the amplitude or intensity of the echo signal.
  • the first coordinate conversion unit 323 performs coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly, and then performs interpolation processing between the sound line data to produce sound.
  • the gap between the line data is filled, and new B-mode image data (new B-mode image data) after synthesizing two RF data having different frequency characteristics is generated.
  • the first coordinate conversion unit 323 may perform STC (Sensitivity Time Control) correction that amplifies RF data having a larger reception depth with a higher amplification factor. Further, the first coordinate conversion unit 323 may perform signal processing on the sound line data using known techniques such as gain processing and contrast processing.
  • the changeover switch 324 selects the RF data to be input from the RF data of the first A / D converter 301 and the RF data of the second A / D converter 302 based on the changeover signal input from the control panel 5A.
  • the changeover switch 324 outputs the selected RF data to the second log amplifier 312.
  • the second envelope detection unit 325 applies a bandpass filter and an envelope detector to the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
  • the B-mode image data generated by the second coordinate conversion unit 315 is used as the old B-mode image data.
  • the display image data generation unit 326 displays the new B-mode image data generated by the first coordinate conversion unit 323 and the old B-mode image data generated by the second coordinate conversion unit 315 on the display device 4. Generate image data.
  • the display image data generation unit 326 generates display image data in which the new B mode image data and the old B mode image data are arranged side by side.
  • the control panel 5A is provided with a switching selection knob 53.
  • the switching selection knob 53 is rotatable and outputs a switching signal according to the rotation position.
  • the control panel 5A has either RF data of the first A / D converter 301, RF data of the second A / D converter 302, or no RF data selection (no parallel display) according to the rotation position of the switching selection knob 53.
  • the changeover signal of is output to the changeover switch 324.
  • FIG. 16 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3A having the above configuration.
  • the ultrasonic observation device 3A connected to the ultrasonic probe executes the same processing as in steps S101 to S104 described above (steps S301 to S304).
  • step S305 the third frequency analysis unit 319 applies an inverse FFT to the composite spectrum data to generate RF data.
  • the third frequency analysis unit 319 outputs the generated RF data to the first log amplifier 320.
  • step S306 the first log amplifier 320 performs logarithmic conversion on the input voltage amplitude.
  • the first log amplifier 320 outputs the converted voltage amplitude to the first envelope detection unit 321.
  • step S307 the first envelope detection unit 321 performs a bandpass filter and an envelope detection on the data after passing through the first log amplifier 320, and generates digital sound line data indicating the amplitude or intensity of the echo signal. do.
  • step S308 the first coordinate conversion unit 323 generates new B-mode image data by performing coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly.
  • the second log amplifier 312 performs logarithmic conversion on the voltage amplitude input from the changeover switch 324 (step S309).
  • the second log amplifier 312 outputs the converted voltage amplitude to the second envelope detection unit 325.
  • step S310 the second envelope detection unit 325 performs envelope detection or the like on the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
  • step S311 the second coordinate conversion unit 315 performs coordinate conversion to rearrange the sound line data so that the generated sound line data can express the scanning range spatially correctly, and generates the old B mode image data.
  • the new B-mode image data generation processing in steps S303 to S308 and the old B-mode image generation processing in steps S309 to S311 may be performed at the same time, or one of them may be performed first. If there is no RF data selected by the switching selection knob 53, the old B-mode image generation processing in steps S309 to S311 is not performed.
  • step S312 the display image data generation unit 326 generates display image data in which the new B mode image data and the old B mode image data are arranged side by side.
  • step S313 the display image signal generation unit 317 thins out the display image data generated by the superimposition unit 316 and the B-mode image data according to the display range of the image in the display device 4, and performs gradation processing.
  • a display image signal is generated by performing a predetermined process such as, and is output to the display device 4 for display.
  • the B-mode image data to be displayed is generated by using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal. .. Since the display image data generation unit 326 generates a new B-mode image in a sufficient frequency band, it is possible to obtain B-mode image data with high resolution. According to the third embodiment, it becomes easy to discriminate subtle differences between tissues in the B mode image.
  • FIG. 17 is a block diagram showing a configuration of an ultrasonic diagnostic system 1B including the ultrasonic observation device 3B according to the fourth embodiment of the present invention.
  • the same configurations as those described in the first embodiment are designated by the same reference numerals and have the same functions as those described in the first embodiment.
  • the ultrasonic diagnostic system 1B according to the fourth embodiment includes an ultrasonic observation device 3B instead of the ultrasonic observation device 3 for the configuration of the ultrasonic diagnostic system 1 according to the first embodiment described above, and is a control panel.
  • a control panel 5B is provided instead of 5.
  • the ultrasonic observation apparatus 3B includes a fourth frequency analysis unit 327 and a superposition ratio setting knob 54.
  • the fourth frequency analysis unit 327 performs an inverse FFT on the composite spectrum data from the synthesis unit 307.
  • the data generated by the processing of the fourth frequency analysis unit 327 corresponds to the composite data of the RF data output from the first A / D converter 301 and the second A / D converter 302.
  • the fourth frequency analysis unit 327 outputs the generated RF data to the second log amplifier 312.
  • the control panel 5B is provided with a superposition ratio setting knob 54.
  • the superposition ratio setting knob 54 is rotatable and outputs a setting signal according to the rotation position.
  • the superimposition ratio setting knob 54 inputs the superimposition ratio of the feature amount image data in the superimposition unit 316.
  • B) is set.
  • ratios such as 100: 0, 0: 100, 50:50, and 70:30 are set according to the ratio that can be superimposed.
  • FIG. 18 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3B having the above configuration.
  • the ultrasonic observation device 3B executes the same processing as in steps S101 to S107 described above (steps S401 to S407).
  • the process of the fourth frequency analysis unit 327 is performed in parallel with the logarithmic conversion process of step S405.
  • the fourth frequency analysis unit 327 applies an inverse FFT to the synthesized spectrum data to generate RF data (step S408).
  • the fourth frequency analysis unit 327 outputs the generated RF data to the second log amplifier 312.
  • step S409 the second log amplifier 312 performs logarithmic conversion on the voltage amplitude input from the fourth frequency analysis unit 327 (step S309).
  • the second log amplifier 312 outputs the converted voltage amplitude to the second envelope detection unit 325.
  • the ultrasonic observation device 3B executes the same processing as in steps S110 to S113 described above (steps S410 to S413).
  • the superimposition unit 316 superimposes the feature amount image data on the B mode image data based on the superimposition ratio data input from the superimposition ratio setting knob 54, and displays the display image data displayed on the display device 4. Generate.
  • the feature amount is calculated using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal.
  • the feature amount calculation unit 309 can obtain a regression line in a sufficient frequency band. This makes it possible to calculate the feature amount more accurately than in the case of obtaining the regression line using only the high-frequency echo signal or only the low-frequency echo signal. According to the fourth embodiment, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
  • the B mode image data to be displayed is generated by using the RF data obtained by synthesizing the high frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low frequency echo signal. do. Since the new B-mode image is generated in a sufficient frequency band in the second coordinate conversion unit 315, B-mode image data having high resolution can be obtained. According to the fourth embodiment, it becomes easy to discriminate subtle differences between tissues in the B mode image.
  • circuits having each function may be connected by a bus, or some functions may be incorporated in a circuit structure of another function.
  • ultrasonic probe an intraluminal ultrasonic probe having no optical lens and an imaging element and an ultrasonic endoscope having an imaging optical system have been described.
  • a small-diameter ultrasonic miniature probe without an optical system may be applied.
  • Ultrasonic miniature probes are usually inserted into the biliary tract, bile ducts, pancreatic ducts, trachea, bronchi, urethra, and ureters and used to observe surrounding organs (pancreas, lungs, prostate, bladder, lymph nodes, etc.).
  • an extracorporeal ultrasonic probe that irradiates ultrasonic waves from the body surface of the subject may be applied.
  • Extracorporeal ultrasound probes are typically used in direct contact with the body surface when observing abdominal organs (liver, gallbladder, bladder), breasts (particularly mammary glands), and thyroid glands.
  • the ultrasonic vibrator may be a linear type vibrator, a radial type vibrator, or a convex vibrator.
  • its scanning area is rectangular (rectangular, square)
  • the ultrasonic oscillator is a radial oscillator or convex oscillator
  • its scanning area is fan-shaped or annular. Rectangle.
  • the ultrasonic vibrator may have a piezoelectric element arranged two-dimensionally.
  • the ultrasonic endoscope may be one that mechanically scans the ultrasonic vibrator, or a plurality of elements are provided in an array as the ultrasonic vibrator, and the elements involved in transmission / reception are electronically switched. Alternatively, it may be electronically scanned by delaying the transmission and reception of each element.
  • the ultrasonic observation device is not limited to the stationary type, and may be a portable or wearable device.
  • the ultrasonic observation device is required to be miniaturized.
  • the diameter of the ultrasonic probe itself is required to be reduced, there is no space for arranging the ultrasonic vibrator, and the frequency band tends to be narrowed.
  • the present invention may include various embodiments within a range that does not deviate from the technical idea described in the claims.
  • the ultrasonic image generator, the operation method of the ultrasonic image generator, the operation program of the ultrasonic image generator, and the ultrasonic image generation circuit according to the present invention are images based on the ultrasonic signal. It is useful for obtaining an image that expresses the properties of the tissue with high accuracy.

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Abstract

The ultrasound image generation device according to the present invention generates an ultrasound image by receiving a first ultrasound signal and a second ultrasound signal having frequency characteristics that are different from those of the first ultrasound signal from ultrasound echoes, and comprises: a first frequency analysis unit generating a first frequency spectrum data for a first ultrasound signal; a second frequency analysis unit generating a second frequency spectrum data for a second ultrasound signal; a combining unit for combining the first frequency spectrum data and the second frequency spectrum data to generate a combined spectrum data; and a display image data generation unit generating, on the basis of the combined spectrum data, display image data to be displayed by a display device.

Description

超音波画像生成装置、超音波画像生成装置の作動方法、超音波画像生成装置の作動プログラムおよび超音波画像生成回路Ultrasound image generator, ultrasonic image generator operating method, ultrasonic image generator operating program and ultrasonic image generation circuit
　本発明は、超音波を用いて患者や動物等の組織を被検体として観測する超音波画像生成装置、超音波画像生成装置の作動方法、超音波画像生成装置の作動プログラムおよび超音波画像生成回路に関する。 The present invention relates to an ultrasonic image generator for observing tissues such as patients and animals as a subject using ultrasonic waves, an operation method of the ultrasonic image generator, an operation program of the ultrasonic image generator, and an ultrasonic image generation circuit. Regarding.
　従来、超音波を用いた観測対象の組織性状を表す技術として、観測対象で後方散乱された超音波エコーを超音波振動子で受信して超音波信号へ変換し、変換された超音波信号の周波数スペクトルから特徴量を算出し、算出された特徴量を画像化する技術が知られている（例えば、特許文献１を参照）。なお、音波の散乱とは、音波が媒体中で粒子と衝突したりして力を及ぼしあうこと（これを相互作用という）によって、音波がその進行方向を変えられる物理現象である。さらに、後方散乱とは、散乱のうち音源の方向に戻ってくる現象またはその成分のことである。この現象は一般に反射とも言われるが、本願では以下、後方散乱の語を用いる。このときの音源は超音波振動子である。この技術では、観測対象の組織性状を表す解析値として周波数スペクトルの特徴量を抽出する。その後、この特徴量に対応する視覚的な情報、例えば色情報を付与した特徴量画像を生成する。そして、超音波信号に基づく超音波画像に特徴量画像を重畳し、重畳画像を生成して表示する。医師等の術者は、表示された重畳画像を見ることによって観測対象の組織性状を診断することができる。 Conventionally, as a technique for expressing the texture of an observation target using ultrasonic waves, an ultrasonic echo echoed backward by the observation target is received by an ultrasonic vibrator and converted into an ultrasonic signal, and the converted ultrasonic signal is used. A technique of calculating a feature amount from a frequency spectrum and imaging the calculated feature amount is known (see, for example, Patent Document 1). Scattering of sound waves is a physical phenomenon in which sound waves can change their traveling direction by colliding with particles in a medium and exerting forces on each other (this is called interaction). Further, backscattering is a phenomenon or a component thereof that returns to the direction of the sound source in the scattering. This phenomenon is also generally referred to as reflection, but in the present application, the term backscattering will be used. The sound source at this time is an ultrasonic vibrator. In this technique, the feature amount of the frequency spectrum is extracted as an analysis value representing the texture of the observation target. After that, a feature amount image to which visual information corresponding to this feature amount, for example, color information is added is generated. Then, the feature amount image is superimposed on the ultrasonic image based on the ultrasonic signal, and the superimposed image is generated and displayed. A surgeon such as a doctor can diagnose the tissue properties of the observation target by looking at the displayed superimposed image.
　特許文献１は、周波数スペクトルごとに特徴量算出用の周波数帯域を設定し、設定した周波数帯域の超音波信号から特徴量を算出する。特許文献１によれば、周波数帯域を個別に設定することによって特徴量の精度を高くしている。 In Patent Document 1, a frequency band for calculating a feature amount is set for each frequency spectrum, and the feature amount is calculated from an ultrasonic signal in the set frequency band. According to Patent Document 1, the accuracy of the feature amount is improved by setting the frequency band individually.
　ところで、上述した超音波振動子を備える超音波プローブとして、細径の超音波プローブが知られている（例えば、特許文献２を参照）。この細径の超音波プローブは、胆膵管、尿管、気管支（特に末梢）等の比較的細い管腔の観察に用いられる。特許文献２は、互いに異なる周波数特性を有する超音波を送受信する超音波送受信部を備える細径の超音波プローブを用いて、各超音波送受信部から受信した信号に対し、超音波送受信部からの深度に応じた重み付けを行って超音波画像を生成する。特許文献２は、周波数特性の異なる複数の超音波画像を同一の画像上で滑らかな画像として合成表示する。 By the way, as an ultrasonic probe provided with the above-mentioned ultrasonic vibrator, a small-diameter ultrasonic probe is known (see, for example, Patent Document 2). This small-diameter ultrasonic probe is used for observing relatively small lumens such as the biliary pancreatic duct, ureter, and bronchi (particularly peripheral). Patent Document 2 uses a small-diameter ultrasonic probe provided with an ultrasonic transmitter / receiver for transmitting / receiving ultrasonic waves having different frequency characteristics, and receives a signal from each ultrasonic transmitter / receiver from the ultrasonic transmitter / receiver. An ultrasonic image is generated by weighting according to the depth. Patent Document 2 composites and displays a plurality of ultrasonic images having different frequency characteristics as smooth images on the same image.
特許第５９３２１８４号公報Japanese Patent No. 5932184 特開平８－１７３４２０号公報Japanese Unexamined Patent Publication No. 8-173420
　こうした細径の超音波プローブでは、配設する超音波振動子を小さくせざるを得ない。超音波振動子が小さくなると、周波数帯域を広く取れなくなり、特徴量の算出精度が低下する場合があった。特に、超音波振動子から遠い深度では、超音波の高周波成分が減衰し、もともと狭いスペクトルの有効帯域がさらに狭くなってしまう。そのため、特徴量算出精度の低下が顕著になる。ここで、有効帯域とは、周波数帯域のうちの、ノイズレベルよりも高いレベルの周波数成分のことである。特許文献１では、既に得られている周波数スペクトルに対して特徴量算出用の周波数帯域を他の有効帯域に変えているため、変えた後の有効帯域においては特徴量を高い精度で算出できる。しかしながら、超音波振動子が小さい場合には、もともと有効帯域を全て合わせても帯域幅が狭く、変えることが難しいため、特徴量算出の精度をさらに高くする工夫が求められる。 With such a small-diameter ultrasonic probe, the ultrasonic transducer to be arranged must be made smaller. When the ultrasonic vibrator becomes small, the frequency band cannot be widened, and the calculation accuracy of the feature amount may decrease. In particular, at a depth far from the ultrasonic transducer, the high-frequency component of the ultrasonic wave is attenuated, and the effective band of the originally narrow spectrum is further narrowed. Therefore, the feature amount calculation accuracy is significantly reduced. Here, the effective band is a frequency component having a level higher than the noise level in the frequency band. In Patent Document 1, since the frequency band for calculating the feature amount is changed to another effective band with respect to the frequency spectrum already obtained, the feature amount can be calculated with high accuracy in the changed effective band. However, when the ultrasonic vibrator is small, the bandwidth is originally narrow even if all the effective bands are combined, and it is difficult to change the bandwidth. Therefore, it is necessary to devise a method for further improving the accuracy of feature calculation.
　また、超音波の高周波成分が減衰したり、周波数成分の有効領域が狭くなったりして、スペクトルの乱れが顕著になると、超音波信号に基づく画像、例えば、超音波エコーの受信強度を画像の輝度で表した、Ｂモード画像の分解能も低下する。 Further, when the high frequency component of the ultrasonic wave is attenuated or the effective region of the frequency component is narrowed and the spectral disturbance becomes remarkable, the reception intensity of the image based on the ultrasonic signal, for example, the ultrasonic echo is measured. The resolution of the B-mode image, expressed in terms of brightness, also decreases.
　本発明は、上記に鑑みてなされたものであって、超音波信号に基づく画像であって、組織の性状を高精度に表現する画像を得ることができる超音波画像生成装置、超音波画像生成装置の作動方法、超音波画像生成装置の作動プログラムおよび超音波画像生成回路を提供することを目的とする。 The present invention has been made in view of the above, and is an ultrasonic image generator, an ultrasonic image generator capable of obtaining an image based on an ultrasonic signal and expressing the properties of a tissue with high accuracy. It is an object of the present invention to provide an operation method of an apparatus, an operation program of an ultrasonic image generator, and an ultrasonic image generation circuit.
　上述した課題を解決し、目的を達成するために、本発明に係る超音波画像生成装置は、超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する超音波画像生成装置において、前記第１の超音波信号について第１の周波数スペクトルデータを生成する第１周波数解析部と、前記第２の超音波信号について第２の周波数スペクトルデータを生成する第２周波数解析部と、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成する合成部と、前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する表示画像データ生成部と、を備えることを特徴とする。 In order to solve the above-mentioned problems and achieve the object, the ultrasonic image generator according to the present invention has frequency characteristics different from those of the first ultrasonic signal and the first ultrasonic signal from the ultrasonic echo. In an ultrasonic image generator that receives different second ultrasonic signals and generates an ultrasonic image, a first frequency analysis unit that generates first frequency spectrum data for the first ultrasonic signal and the first frequency analysis unit. A second frequency analysis unit that generates a second frequency spectrum data for the ultrasonic signal of 2, and a synthesis unit that synthesizes the first frequency spectrum data and the second frequency spectrum data to generate a composite spectrum data. It is characterized by including a display image data generation unit that generates display image data to be displayed on the display device based on the composite spectrum data.
　本発明に係る超音波画像生成装置は、上記発明において、前記合成スペクトルデータに基づいて特徴量を算出する特徴量算出部、前記特徴量に応じて色情報を付与した特徴量画像データを生成する特徴量画像データ生成部と、をさらに備えることを特徴とする。 In the above invention, the ultrasonic image generator according to the present invention generates a feature amount calculation unit that calculates a feature amount based on the composite spectrum data, and a feature amount image data to which color information is added according to the feature amount. It is characterized by further including a feature amount image data generation unit.
　本発明に係る超音波画像生成装置は、上記発明において、前記特徴量算出部は、前記合成スペクトルデータから算出した回帰直線に基づいて前記特徴量を算出することを特徴とする。 The ultrasonic image generator according to the present invention is characterized in that, in the above invention, the feature amount calculation unit calculates the feature amount based on a regression line calculated from the composite spectrum data.
　本発明に係る超音波画像生成装置は、上記発明において、前記第１の超音波信号および前記第２の超音波信号のうちの少なくとも一方を用いてＢモード画像データを生成するＢモード画像データ生成部、をさらに備えることを特徴とする。 In the above invention, the ultrasonic image generator according to the present invention uses at least one of the first ultrasonic signal and the second ultrasonic signal to generate B-mode image data. It is characterized by further providing a part.
　本発明に係る超音波画像生成装置は、上記発明において、前記合成部は、線形表現の前記第１の周波数スペクトルデータと、線形表現の前記第２の周波数スペクトルデータとを加算して前記合成スペクトルデータを生成することを特徴とする。 In the ultrasonic image generator according to the present invention, in the above invention, the synthesis unit adds the first frequency spectrum data of the linear representation and the second frequency spectrum data of the linear representation to the composite spectrum. It is characterized by generating data.
　本発明に係る超音波画像生成装置は、上記発明において、前記第１の超音波信号および前記第２の超音波信号のうちの少なくとも一方を用いてＢモード画像データを生成するＢモード画像データ生成部、をさらに備え、前記画像データ生成部は、前記特徴量画像データの座標と、前記Ｂモード画像データの座標とを対応させて、前記特徴量に応じた色情報を前記Ｂモード画像データ上に配置することを特徴とする。 In the above invention, the ultrasonic image generator according to the present invention uses at least one of the first ultrasonic signal and the second ultrasonic signal to generate B-mode image data. The image data generation unit further comprises a unit, and the image data generation unit associates the coordinates of the feature amount image data with the coordinates of the B mode image data, and provides color information according to the feature amount on the B mode image data. It is characterized by being placed in.
　本発明に係る超音波画像生成装置は、上記発明において、前記Ｂモード画像データ生成部は、前記合成スペクトルデータを用いて前記Ｂモード画像データを生成することを特徴とする。 The ultrasonic image generator according to the present invention is characterized in that, in the above invention, the B-mode image data generation unit generates the B-mode image data using the synthetic spectrum data.
　本発明に係る超音波画像生成装置は、上記発明において、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとの取得位置を補正する位置補正部、をさらに備えることを特徴とする。 The ultrasonic image generator according to the present invention is characterized in that, in the above invention, further includes a position correction unit for correcting the acquisition position of the first frequency spectrum data and the second frequency spectrum data.
　本発明に係る超音波画像生成装置は、上記発明において、前記Ｂモード画像データ生成部は、前記第１の周波数スペクトルデータと、前記第２の周波数スペクトルデータとを、設定される混合割合に応じて混合して前記Ｂモード画像データを生成することを特徴とする。 In the ultrasonic image generation device according to the present invention, in the above invention, the B mode image data generation unit mixes the first frequency spectrum data and the second frequency spectrum data according to a set mixing ratio. The B-mode image data is generated by mixing the data.
　本発明に係る超音波画像生成装置は、上記発明において、前記表示画像データ生成部は、設定される前記特徴量画像データの重畳割合に応じて、前記特徴量画像データを前記Ｂモード画像データに重畳することを特徴とする。 In the ultrasonic image generation device according to the present invention, in the above invention, the display image data generation unit converts the feature amount image data into the B mode image data according to a set superposition ratio of the feature amount image data. It is characterized by superimposing.
　本発明に係る超音波画像生成装置は、上記発明において、前記合成スペクトルデータを対数変換するログアンプ、をさらに備えることを特徴とする。 The ultrasonic image generator according to the present invention is characterized in that, in the above invention, further includes a log amplifier for logarithmically transforming the synthesized spectrum data.
　本発明に係る超音波画像生成装置の作動方法は、超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する超音波画像生成装置の作動方法であって、第１周波数解析部が、前記第１の超音波信号について第１の周波数スペクトルデータを生成し、第２周波数解析部が、前記第２の超音波信号について第２の周波数スペクトルデータを生成し、合成部が、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、画像データ生成部が、前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成することを特徴とする。 The operating method of the ultrasonic image generator according to the present invention receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo. A method of operating an ultrasonic image generator that generates an ultrasonic image, in which a first frequency analysis unit generates first frequency spectrum data for the first ultrasonic signal, and a second frequency analysis unit generates first frequency spectrum data. The second frequency spectrum data is generated for the second ultrasonic signal, and the synthesizer synthesizes the first frequency spectrum data and the second frequency spectrum data to generate the composite spectrum data, and the image The data generation unit is characterized in that the display image data to be displayed on the display device is generated based on the composite spectrum data.
　本発明に係る超音波画像生成装置の作動プログラムは、超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する超音波画像生成装置に実行させる作動プログラムであって、前記第１の超音波信号について第１の周波数スペクトルデータを生成し、前記第２の超音波信号について第２の周波数スペクトルデータを生成し、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成することを特徴とする。 The operation program of the ultrasonic image generator according to the present invention receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo. An operation program executed by an ultrasonic image generator that generates an ultrasonic image, which generates first frequency spectrum data for the first ultrasonic signal and a second frequency for the second ultrasonic signal. Spectral data is generated, the first frequency spectrum data and the second frequency spectrum data are combined to generate synthetic spectrum data, and based on the synthetic spectrum data, display image data to be displayed on a display device is generated. It is characterized by generating.
　本発明に係る超音波画像生成回路は、超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信し、前記第１の超音波信号について第１の周波数スペクトルデータを生成し、前記第２の超音波信号について第２の周波数スペクトルデータを生成し、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する、処理を実行することを特徴とする。 The ultrasonic image generation circuit according to the present invention receives a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal from the ultrasonic echo, and receives the first ultrasonic signal. A first frequency spectrum data is generated for the ultrasonic signal of the above, a second frequency spectrum data is generated for the second ultrasonic signal, and the first frequency spectrum data and the second frequency spectrum data are combined. It is characterized in that a process of generating synthetic spectrum data by synthesizing and generating display image data to be displayed on a display device based on the synthetic spectrum data is executed.
　本発明によれば、超音波信号に基づく画像であって、組織の性状を高精度に表現する画像を得ることができるという効果を奏する。 According to the present invention, it is possible to obtain an image based on an ultrasonic signal that expresses the properties of a tissue with high accuracy.
図１は、本発明の実施の形態１に係る超音波観測装置を備えた超音波診断システムの構成を示すブロック図である。FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a first embodiment of the present invention. 図２は、超音波プローブにおける超音波振動子の構成を説明する図である。FIG. 2 is a diagram illustrating a configuration of an ultrasonic vibrator in an ultrasonic probe. 図３は、超音波振動子の走査領域と音線データとを模式的に示す図である。FIG. 3 is a diagram schematically showing the scanning region of the ultrasonic vibrator and the sound line data. 図４は、超音波信号の１つの音線上のＲＦデータにおけるデータ配列を模式的に示す図である。FIG. 4 is a diagram schematically showing a data arrangement in RF data on one sound line of an ultrasonic signal. 図５は、本発明の実施の形態１に係る超音波観測装置において用いられるスペクトルデータについて説明する図である。FIG. 5 is a diagram illustrating spectrum data used in the ultrasonic observation device according to the first embodiment of the present invention. 図６Ａは、周波数スペクトルを用いた周波数特徴量の算出を説明するための図（その１）である。FIG. 6A is a diagram (No. 1) for explaining the calculation of the frequency feature amount using the frequency spectrum. 図６Ｂは、周波数スペクトルを用いた周波数特徴量の算出を説明するための図（その２）である。FIG. 6B is a diagram (No. 2) for explaining the calculation of the frequency feature amount using the frequency spectrum. 図６Ｃは、周波数スペクトルを用いた周波数特徴量の算出を説明するための図（その３）である。FIG. 6C is a diagram (No. 3) for explaining the calculation of the frequency feature amount using the frequency spectrum. 図７は、本発明の実施の形態１に係る超音波観測装置が行う処理の概要を示すフローチャートである。FIG. 7 is a flowchart showing an outline of the processing performed by the ultrasonic observation apparatus according to the first embodiment of the present invention. 図８は、本発明の実施の形態１に係る超音波観測装置の周波数解析部が実行する処理の概要を示すフローチャートである。FIG. 8 is a flowchart showing an outline of the processing executed by the frequency analysis unit of the ultrasonic observation apparatus according to the first embodiment of the present invention. 図９は、超音波信号に基づく画像の表示例を示す図である。FIG. 9 is a diagram showing a display example of an image based on an ultrasonic signal. 図１０は、超音波プローブが記憶する位置補正データの設定について説明する図（その１）である。FIG. 10 is a diagram (No. 1) for explaining the setting of the position correction data stored in the ultrasonic probe. 図１１は、超音波プローブが記憶する位置補正データの設定について説明する図（その２）である。FIG. 11 is a diagram (No. 2) for explaining the setting of the position correction data stored in the ultrasonic probe. 図１２は、超音波プローブが記憶する位置補正データの設定について説明する図（その３）である。FIG. 12 is a diagram (No. 3) for explaining the setting of the position correction data stored in the ultrasonic probe. 図１３は、本発明の実施の形態２に係る超音波プローブの要部の構成を説明する図である。FIG. 13 is a diagram illustrating a configuration of a main part of the ultrasonic probe according to the second embodiment of the present invention. 図１４は、本発明の実施の形態２の変形例に係る超音波プローブの要部の構成を説明する図である。FIG. 14 is a diagram illustrating a configuration of a main part of an ultrasonic probe according to a modified example of the second embodiment of the present invention. 図１５は、本発明の実施の形態３に係る超音波観測装置を備えた超音波診断システムの構成を示すブロック図である。FIG. 15 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a third embodiment of the present invention. 図１６は、本発明の実施の形態３に係る超音波観測装置が行う処理の概要を示すフローチャートである。FIG. 16 is a flowchart showing an outline of processing performed by the ultrasonic observation apparatus according to the third embodiment of the present invention. 図１７は、本発明の実施の形態４に係る超音波観測装置を備えた超音波診断システムの構成を示すブロック図である。FIG. 17 is a block diagram showing a configuration of an ultrasonic diagnostic system including an ultrasonic observation device according to a fourth embodiment of the present invention. 図１８は、本発明の実施の形態４に係る超音波観測装置が行う処理の概要を示すフローチャートである。FIG. 18 is a flowchart showing an outline of the processing performed by the ultrasonic observation apparatus according to the fourth embodiment of the present invention.
　以下、添付図面を参照して、本発明を実施するための形態（以下、「実施の形態」という）を説明する。 Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings.
（実施の形態１）
　図１は、本発明の実施の形態１に係る超音波観測装置３を備えた超音波診断システム１の構成を示すブロック図である。同図に示す超音波診断システム１は、被検体へ超音波を送信し、該被検体で後方散乱された超音波を受信する超音波プローブ２と、接続された超音波プローブ２が取得した超音波信号に基づいて超音波画像を生成する超音波観測装置３と、超音波観測装置３が生成した超音波画像を表示する表示装置４と、画像データの生成に関する各種情報を入力するコントロールパネル５とを備える。本実施の形態では、超音波プローブ２として、管腔内超音波プローブが用いられる。ブロック図では、実線の矢印が周波数スペクトルや特徴量に係る電気信号の伝送を示し、点線の矢印がＢモード画像に係る電気信号やデータの伝送を示し、一点鎖線の矢印が制御やその他に係る電気信号やデータの伝送を示し、二重線の矢印が最終的に表示装置４に表示する画像に係る電気信号やデータの伝送を示している。なお、超音波送信系の回路構成については説明の都合上、省略した。 (Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic system 1 provided with an ultrasonic observation device 3 according to a first embodiment of the present invention. The ultrasonic diagnostic system 1 shown in the figure is an ultrasonic probe 2 that transmits ultrasonic waves to a subject and receives ultrasonic waves back-scattered by the subject, and an ultrasonic probe 2 acquired by the connected ultrasonic probe 2. An ultrasonic observation device 3 that generates an ultrasonic image based on an ultrasonic signal, a display device 4 that displays an ultrasonic image generated by the ultrasonic observation device 3, and a control panel 5 that inputs various information related to the generation of image data. And. In the present embodiment, an intraluminal ultrasonic probe is used as the ultrasonic probe 2. In the block diagram, the solid line arrow indicates the transmission of electrical signals related to the frequency spectrum and feature quantities, the dotted line arrow indicates the transmission of electrical signals and data related to the B-mode image, and the single-point chain line arrow indicates control and others. The transmission of electrical signals and data is indicated, and the double-lined arrows indicate the transmission of electrical signals and data related to the image finally displayed on the display device 4. The circuit configuration of the ultrasonic transmission system has been omitted for convenience of explanation.
　超音波プローブ２は、細径の超音波プローブの１例であり、被検体内に挿入される可撓性の挿入部２１と、挿入部２１の基端側に接続する操作部２２とを有する。挿入部２１には、その先端部に、超音波観測装置３から受信した電気的なパルス信号を超音波パルス（音響パルス）に変換して被検体へ照射するとともに、被検体で後方散乱された超音波エコーを電圧変化で表現する電気的なエコー信号に変換する超音波振動子（第１超音波振動子２１１および第２超音波振動子２１２）を有する（図２参照）。 The ultrasonic probe 2 is an example of a small-diameter ultrasonic probe, and has a flexible insertion portion 21 inserted into a subject and an operation portion 22 connected to the proximal end side of the insertion portion 21. .. At the tip of the insertion portion 21, the electrical pulse signal received from the ultrasonic observation device 3 is converted into an ultrasonic pulse (acoustic pulse) and irradiated to the subject, and the subject is backscattered by the subject. It has an ultrasonic transducer (first ultrasonic transducer 211 and second ultrasonic transducer 212) that converts an ultrasonic echo into an electrical echo signal expressed by a voltage change (see FIG. 2).
　図２は、超音波プローブにおける超音波振動子の構成を説明する図である。挿入部２１は、その先端部に、二つの超音波振動子（第１超音波振動子２１１および第２超音波振動子２１２）と、超音波振動子間に設けられるバッキング材２１３と、一端がバッキング材２１３に接続し、他端が操作部２２側に延びる可撓性のフレキシブルシャフト２１４とを有する。 FIG. 2 is a diagram illustrating a configuration of an ultrasonic vibrator in an ultrasonic probe. The insertion portion 21 has two ultrasonic vibrators (first ultrasonic vibrator 211 and second ultrasonic vibrator 212) and a backing material 213 provided between the ultrasonic vibrators at one end thereof. It has a flexible flexible shaft 214 which is connected to the backing material 213 and the other end extends toward the operation portion 22 side.
　第１超音波振動子２１１および第２超音波振動子２１２は、互いに異なる周波数特性の超音波ビームを送信する超音波振動子である。各超音波振動子は、走査面上で超音波ビームＥ1、Ｅ2をそれぞれ送信し、後方散乱によって戻ってきた超音波を受信する。第１超音波振動子２１１および第２超音波振動子２１２は、それぞれ走査面ＰSを走査して、該走査面ＰSを経て戻ってくる超音波を受信する。なお、図２に示す走査面ＰSは、表示装置４における表示画面に対応する矩形で表現している。
　本実施の形態１において、第１超音波振動子２１１が送信する超音波ビームＥ1の周波数は、第２超音波振動子２１２が送信する超音波ビームＥ2の周波数よりも高い。すなわち、本実施の形態１において、第１超音波振動子２１１は高周波タイプの超音波振動子、第２超音波振動子２１２は低周波タイプの超音波振動子である。超音波振動子は、圧電素子を用いて構成される。 The first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 are ultrasonic vibrators that transmit ultrasonic beams having different frequency characteristics from each other. Each ultrasonic transducer transmits ultrasonic beams E 1 and E 2 on the scanning surface, respectively, and receives the ultrasonic waves returned by backscattering. The first ultrasonic transducer 211 and the second ultrasonic transducer 212 are each scanned scanning plane P S, receives the come ultrasound back through the scanning plane P S. The scanning plane P S shown in FIG. 2 is represented by a rectangle corresponding to the display screen of the display device 4.
In the first embodiment, the frequency of the ultrasonic beam E 1 transmitted by the first ultrasonic vibrator 211 is higher than the frequency of the ultrasonic beam E 2 transmitted by the second ultrasonic vibrator 212. That is, in the first embodiment, the first ultrasonic vibrator 211 is a high frequency type ultrasonic vibrator, and the second ultrasonic vibrator 212 is a low frequency type ultrasonic vibrator. The ultrasonic vibrator is configured by using a piezoelectric element.
　バッキング材２１３は、圧電素子の動作によって生じる不要な超音波振動を減衰させる部材である。具体的に、バッキング材２１３は、第１超音波振動子２１１および第２超音波振動子２１２が有する圧電素子の動作によって生じる不要な超音波振動を減衰させる。バッキング材２１３によって、一方の超音波振動子から他方の超音波振動子への不要な超音波振動の伝搬を抑制できる。バッキング材１３は、減衰率の大きい材料を用いて形成される。 The backing material 213 is a member that attenuates unnecessary ultrasonic vibration generated by the operation of the piezoelectric element. Specifically, the backing material 213 attenuates unnecessary ultrasonic vibrations generated by the operation of the piezoelectric elements of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212. The backing material 213 can suppress the propagation of unnecessary ultrasonic vibration from one ultrasonic vibrator to the other ultrasonic vibrator. The backing material 13 is formed by using a material having a large damping rate.
　フレキシブルシャフト２１４は、屈曲自在な材料を用いて構成される。フレキシブルシャフト２１４は、例えば超音波観測装置３の制御のもと、長手方向に延びる軸を中心に回転する。フレキシブルシャフト２１４が回転すると、第１超音波振動子２１１および第２超音波振動子２１２も回転する。第１超音波振動子２１１および第２超音波振動子２１２の回転によって、挿入部２１の先端部の周方向における、第１超音波振動子２１１および第２超音波振動子２１２の位置が変更される。フレキシブルシャフト２１４内には、第１超音波振動子２１１に接続する高周波用信号線、および第２超音波振動子２１２に接続する低周波用信号線が挿通される。第１超音波振動子２１１および第２超音波振動子２１２は、各信号線を経由して、超音波観測装置３に信号を送信する。 The flexible shaft 214 is constructed using a flexible material. The flexible shaft 214 rotates about an axis extending in the longitudinal direction under the control of, for example, the ultrasonic observation device 3. When the flexible shaft 214 rotates, the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 also rotate. The rotation of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 changes the positions of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 in the circumferential direction of the tip of the insertion portion 21. NS. A high-frequency signal line connected to the first ultrasonic vibrator 211 and a low-frequency signal line connected to the second ultrasonic vibrator 212 are inserted into the flexible shaft 214. The first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 transmit a signal to the ultrasonic observation device 3 via each signal line.
　再び図１に戻り、操作部２２は、例えば医師等の術者によって把持される。操作部２２は、その内部に記憶部２２１を有する。記憶部２２１は、第１超音波振動子２１１および第２超音波振動子２１２の位置関係に関し、各超音波振動子の位置関係を補正する位置補正データを記憶する。 Returning to FIG. 1, the operation unit 22 is gripped by an operator such as a doctor. The operation unit 22 has a storage unit 221 inside. The storage unit 221 stores the position correction data for correcting the positional relationship of each ultrasonic vibrator with respect to the positional relationship of the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212.
　超音波観測装置３は、接続部３００、第１Ａ／Ｄコンバータ３０１、第２Ａ／Ｄコンバータ３０２、第１周波数解析部３０３、第２周波数解析部３０４、バッファ３０５、３０６、３１４、合成部３０７、第１ログアンプ３０８、特徴量算出部３０９、第１座標変換部３１０、混合部３１１、第２ログアンプ３１２、包絡線検波部３１３、第２座標変換部３１５、重畳部３１６、表示画像信号生成部３１７および記憶部３１８を備える。超音波観測装置３は、超音波画像生成装置に相当する。 The ultrasonic observation device 3 includes a connection unit 300, a first A / D converter 301, a second A / D converter 302, a first frequency analysis unit 303, a second frequency analysis unit 304, a buffer 305, 306, 314, and a synthesis unit 307. 1st log amplifier 308, feature amount calculation unit 309, 1st coordinate conversion unit 310, mixing unit 311, 2nd log amplifier 312, envelope detection unit 313, 2nd coordinate conversion unit 315, superimposition unit 316, display image signal generation A unit 317 and a storage unit 318 are provided. The ultrasonic observation device 3 corresponds to an ultrasonic image generator.
　接続部３００は、高周波信号線と接続する高周波用接続ピン３００ａと、低周波用信号線と接続する低周波用接続ピン３００ｂとを有し、超音波観測装置３の筐体に固定されている。操作部２２は接続部３００に対して着脱自在である。すなわち、操作部２２は、超音波観測装置３に対して着脱自在である。接続部３００は、高周波用信号線および低周波用信号線を経由して、超音波プローブ２と超音波観測装置３とを電気的に接続する。 The connection portion 300 has a high-frequency connection pin 300a for connecting to the high-frequency signal line and a low-frequency connection pin 300b for connecting to the low-frequency signal line, and is fixed to the housing of the ultrasonic observation device 3. .. The operation unit 22 is removable from the connection unit 300. That is, the operation unit 22 is removable from the ultrasonic observation device 3. The connection unit 300 electrically connects the ultrasonic probe 2 and the ultrasonic observation device 3 via the high-frequency signal line and the low-frequency signal line.
　第１Ａ／Ｄコンバータ３０１は、超音波プローブ２から電気的なラジオ周波数（ＲＦ：Radio　Frequency）の信号であるエコー信号を、高周波用信号線を経由して受信し、エコー信号にＡ／Ｄ変換処理を施してデジタルデータ（以下、ＲＦデータという）を生成、出力する。 The first A / D converter 301 receives an echo signal, which is an electric radio frequency (RF: Radio Frequency) signal, from the ultrasonic probe 2 via a high frequency signal line, and converts it into an echo signal by A / D. It is processed to generate and output digital data (hereinafter referred to as RF data).
　第２Ａ／Ｄコンバータ３０２は、超音波プローブ２から電気的なエコー信号を、低周波用信号線を経由して受信し、エコー信号にＡ／Ｄ変換処理を施してＲＦデータを生成、出力する。 The second A / D converter 302 receives an electrical echo signal from the ultrasonic probe 2 via a low-frequency signal line, performs A / D conversion processing on the echo signal, and generates and outputs RF data. ..
　具体的には、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２は、まず受信したエコー信号を増幅する。第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２は、増幅したエコー信号に対してフィルタリング等の処理を施した後、適当なサンプリング周波数（例えば５０ＭＨｚ）でサンプリングして離散化（いわゆるＡ／Ｄ変換処理）する。こうして、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２は、増幅後のエコー信号から離散化されたＲＦデータを生成する。第１Ａ／Ｄコンバータ３０１は、第１周波数解析部３０３および混合部３１１へＲＦデータを出力する。第２Ａ／Ｄコンバータ３０２は、第２周波数解析部３０４および混合部３１１へＲＦデータを出力する。 Specifically, the first A / D converter 301 and the second A / D converter 302 first amplify the received echo signal. The first A / D converter 301 and the second A / D converter 302 perform processing such as filtering on the amplified echo signal, and then sample at an appropriate sampling frequency (for example, 50 MHz) and discretize (so-called A / D). Conversion processing). In this way, the first A / D converter 301 and the second A / D converter 302 generate discretized RF data from the amplified echo signal. The first A / D converter 301 outputs RF data to the first frequency analysis unit 303 and the mixing unit 311. The second A / D converter 302 outputs RF data to the second frequency analysis unit 304 and the mixing unit 311.
　なお、超音波観測装置３には、超音波プローブ２と電気的に接続され、所定の波形および送信タイミングに基づいて高電圧パルスからなる送信信号（パルス信号）を超音波振動子へ送信する送信回路（図示せず）が２系統設けられる。この送信回路のうちの一方は、第１超音波振動子２１１と接続する。そして、送信するパルス信号の周波数帯域は、第１超音波振動子２１１がパルス信号を超音波パルスへ電気音響変換をする際の、第１超音波振動子２１１の線型応答周波数帯域をほぼカバーする広帯域にする。また、送信回路のうちの別の一方は、第２超音波振動子２１２と接続する。そして、送信するパルス信号の周波数帯域は、第２超音波振動子２１２がパルス信号を超音波パルスへ電気音響変換をする際の、第２超音波振動子２１２の線型応答周波数帯域をほぼカバーする広帯域にする。さらに、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２におけるエコー信号の各種処理周波数帯域は、超音波振動子が超音波エコーをエコー信号へ音響電気変換する際の、超音波振動子の線型応答周波数帯域をほぼカバーする広帯域にする。これらによって、後述する周波数スペクトルの近似処理を実行する際、精度のよい近似を行うことが可能となる。 The ultrasonic observation device 3 is electrically connected to the ultrasonic probe 2 and transmits a transmission signal (pulse signal) composed of a high voltage pulse based on a predetermined waveform and transmission timing to the ultrasonic vibrator. Two circuits (not shown) are provided. One of the transmission circuits is connected to the first ultrasonic transducer 211. The frequency band of the pulse signal to be transmitted substantially covers the linear response frequency band of the first ultrasonic vibrator 211 when the first ultrasonic vibrator 211 converts the pulse signal into an ultrasonic pulse. Make it wideband. Further, another one of the transmission circuits is connected to the second ultrasonic vibrator 212. The frequency band of the pulse signal to be transmitted substantially covers the linear response frequency band of the second ultrasonic vibrator 212 when the second ultrasonic vibrator 212 converts the pulse signal into an ultrasonic pulse. Make it wideband. Further, the various processing frequency bands of the echo signal in the first A / D converter 301 and the second A / D converter 302 are the linear shape of the ultrasonic transducer when the ultrasonic transducer acoustically converts the ultrasonic echo into an echo signal. Make the wide band almost cover the response frequency band. As a result, it is possible to perform an accurate approximation when executing the frequency spectrum approximation processing described later.
　第１周波数解析部３０３は、第１Ａ／Ｄコンバータ３０１が生成したＲＦデータに高速フーリエ変換（ＦＦＴ：Fast　Fourier　Transform）を施して周波数解析を行うことによって周波数スペクトルのデータ（以下、第１スペクトルデータという）を算出する。具体的には、第１周波数解析部３０３は、第１Ａ／Ｄコンバータ３０１が生成した各音線のＲＦデータ（ラインデータ）を比較的短い所定の時間間隔で複数に区切り、区切った各部分のＲＦデータ（以下、「ＲＦデータストリング」と呼ぶ）にＦＦＴ処理を施すことによって、音線の各部分における周波数スペクトルを算出する。ここでいう「周波数スペクトル」とは、ＲＦデータストリングにＦＦＴ処理を施すことによって得られた「ある受信深度ｚ（すなわち、或る往復距離Ｌ）から得られるエコー信号の強度や電圧振幅の周波数分布」を意味する。 The first frequency analysis unit 303 performs frequency analysis by performing a fast Fourier transform (FFT) on the RF data generated by the first A / D converter 301 to perform frequency spectrum data (hereinafter, first spectrum data). ) Is calculated. Specifically, the first frequency analysis unit 303 divides the RF data (line data) of each sound line generated by the first A / D converter 301 into a plurality of pieces at relatively short predetermined time intervals, and divides each part. By applying FFT processing to RF data (hereinafter referred to as "RF data string"), the frequency spectrum in each part of the sound line is calculated. The "frequency spectrum" here means the frequency distribution of the intensity and voltage amplitude of the echo signal obtained from the "certain reception depth z (that is, a certain round-trip distance L)" obtained by subjecting the RF data string to FFT processing. Means.
　本実施の形態１では、周波数スペクトルとしてエコー信号の電圧振幅の周波数分布を採用した場合で説明する。第１周波数解析部３０３は、電圧振幅の周波数成分Ｖ（ｆ）をもとに第１スペクトルのデータを生成する場合を例として説明する。ｆは、周波数である。第１周波数解析部３０３は、ＲＦデータの振幅（事実上、エコー信号の電圧振幅）の周波数成分Ｖ（ｆ）を基準電圧Ｖcで除し、常用対数（ｌｏｇ）をとってデシベル単位で表現する対数変換処理を施した後、適当な正の定数αを乗ずることによって、次式（１）で与えられる被検体の第１スペクトルデータＳ（ｆ）を生成する。
　　Ｓ（ｆ）＝α・ｌｏｇ｛Ｖ（ｆ）／Ｖc｝　　・・・（１）
　なお、本実施の形態１では、α＝２０とする。 In the first embodiment, the case where the frequency distribution of the voltage amplitude of the echo signal is adopted as the frequency spectrum will be described. The case where the first frequency analysis unit 303 generates the data of the first spectrum based on the frequency component V (f) of the voltage amplitude will be described as an example. f is a frequency. The first frequency analysis unit 303 divides the frequency component V (f) of the amplitude of the RF data (in effect, the voltage amplitude of the echo signal) by the reference voltage V c , takes the common logarithm (log), and expresses it in decibel units. After performing the logarithmic conversion process, the first spectrum data S (f) of the subject given by the following equation (1) is generated by multiplying by an appropriate positive constant α.
S (f) = α · log {V (f) / V c } ・ ・ ・ (1)
In the first embodiment, α = 20.
　以下、具体的に、第１周波数解析部３０３での周波数解析によって電圧振幅の周波数成分Ｖ（ｆ）を求める方法について説明する。一般に、エコー信号の周波数スペクトルは、被検体が人体組織である場合、超音波が走査された人体組織の性状によって異なる傾向を示す。これは、周波数スペクトルが、超音波を散乱する散乱体の大きさ、数密度、音響インピーダンス等と相関を有しているためである。ここでいう「人体組織の性状」とは、例えば悪性腫瘍（癌）、良性腫瘍、内分泌腫瘍、粘液性腫瘍、正常組織、嚢胞、脈管など、組織の特徴のことである。 Hereinafter, a method for obtaining the frequency component V (f) of the voltage amplitude by frequency analysis by the first frequency analysis unit 303 will be specifically described. In general, when the subject is a human tissue, the frequency spectrum of the echo signal tends to differ depending on the properties of the human tissue scanned by the ultrasonic waves. This is because the frequency spectrum has a correlation with the size, number density, acoustic impedance, etc. of the scatterer that scatters ultrasonic waves. The "characteristics of human tissue" here refers to the characteristics of tissues such as malignant tumors (cancers), benign tumors, endocrine tumors, mucinous tumors, normal tissues, cysts, and vessels.
　図３は、超音波振動子の走査領域（以下、単に走査領域ということもある）と音線データとを模式的に示す図である。図３に示す走査領域Ｓは円形をなしている。なお、図３では、超音波振動子が、超音波が往復する経路（音線）を直線で、音線データを各音線上に並んだ点で表現している。図３では、後の説明の都合上、各音線に、走査開始（図３右）から順に、１、２、３・・・と番号を付し、１番目の音線をＳＲ1、２番目の音線をＳＲ2、３番目の音線をＳＲ3、・・・、ｋ番目の音線をＳＲkと定義する。また、図３では、音線データの受信深度をｚとして記載している。超音波振動子の表面から照射された超音波パルスが受信深度ｚにある物体内で後方散乱し、超音波エコーとして超音波振動子へ戻ってきた場合、その往復距離Ｌと受信深度ｚとの間には、ｚ＝Ｌ／２の関係がある。 FIG. 3 is a diagram schematically showing a scanning region (hereinafter, may be simply referred to as a scanning region) of the ultrasonic vibrator and sound line data. The scanning area S shown in FIG. 3 has a circular shape. In FIG. 3, the ultrasonic transducer expresses the path (sound line) through which the ultrasonic waves reciprocate as a straight line, and the sound line data as points arranged on each sound line. In FIG. 3, for convenience of later explanation, each sound line is numbered 1, 2, 3, ... In order from the start of scanning (right in FIG. 3), and the first sound line is SR 1 , 2. The third sound line is defined as SR 2 , the third sound line is defined as SR 3 , ..., And the kth sound line is defined as SR k. Further, in FIG. 3, the reception depth of the sound line data is described as z. When the ultrasonic pulse emitted from the surface of the ultrasonic vibrator scatters backward in the object at the reception depth z and returns to the ultrasonic vibrator as an ultrasonic echo, the reciprocating distance L and the reception depth z There is a relationship of z = L / 2 between them.
　図４は、超音波信号の１つの音線ＳＲk上のＲＦデータにおけるデータ配列を模式的に示す図である。音線ＳＲkにおける白抜きまたは黒塗りで示す長方形は、１つのサンプル点におけるデータを意味している。また、音線ＳＲk上のＲＦデータにおいて、右側に位置するデータほど、超音波振動子から音線ＳＲkに沿って計った場合の深い箇所からのＲＦデータである（図４の矢印を参照）。音線ＳＲk上のＲＦデータは、前述の通り、Ａ／ＤコンバータでのＡ／Ｄ変換処理によってエコー信号からサンプリングされ、離散化されたＲＦデータである。図４では、番号ｋの音線ＳＲk上のＲＦデータの８番目のデータ位置を受信深度ｚの方向の初期値Ｚ(k) 0として設定した場合を示しているが、初期値の位置は任意に設定することができる。第１周波数解析部３０３による算出結果は記憶部３１８に格納される。データ位置の最大値Ｚ(k) maxは、音線ＳＲk上での解析範囲の最深のＲＦデータストリングを代表するデータ位置である。この最大値ｋmaxは、図４中、解析範囲の最左の音線の番号である。 FIG. 4 is a diagram schematically showing a data arrangement in RF data on one sound line SR k of an ultrasonic signal. The white or black rectangle on the sound line SR k means the data at one sample point. Further, in the RF data on the sound line SR k , the data located on the right side is the RF data from the deeper part when measured from the ultrasonic transducer along the sound line SR k (see the arrow in FIG. 4). ). As described above, the RF data on the sound line SR k is the RF data sampled from the echo signal by the A / D conversion process in the A / D converter and discretized. In Figure 4, there is shown a case of setting the initial value Z (k) 0 in the direction of the eighth data position reception depth z of the RF data on sound ray SR k of number k, the position of the initial value It can be set arbitrarily. The calculation result by the first frequency analysis unit 303 is stored in the storage unit 318. The maximum value Z (k) max of the data position is a data position representing the deepest RF data string in the analysis range on the sound line SR k. This maximum value k max is the number of the leftmost sound line in the analysis range in FIG.
　図４に示すＲＦデータストリングＦj（ｊ＝１、２、・・・、Ｋ）は、ＲＦデータのうち、ＦＦＴ処理の対象となる部分、である。一般に、ＦＦＴ処理を行うためには、ＲＦデータストリングが２のべき乗のデータ数を有している必要がある。この意味で、ＦK以外のＲＦデータストリングＦj（ｊ＝１、２、・・・、Ｋ－１）はデータ数が１６（＝２4）で正常なＲＦデータストリングである。一方、ＲＦデータストリングＦKは、データ数が１２であるため異常なＲＦデータストリングである。異常なＲＦデータストリングに対してＦＦＴ処理を行う際には、不足分だけゼロデータを挿入することによって、正常なＲＦデータストリングを生成する処理を行う。この点については、周波数解析処理を説明する際に詳述する（図８を参照）。この後、第１周波数解析部３０３は、前述の通り、ＦＦＴ処理を実行し、電圧振幅の周波数成分Ｖ（ｆ）を算出し、前述の式（１）に基づいて第１スペクトルデータＳ（ｆ）を算出する。その後、第１周波数解析部３０３は、データ位置Ｚ(k)をステップ幅Ｄで変化させて、各位置の第１スペクトルデータＳ（ｆ）を算出する。なお、図４では、Ｄ＝１５の場合を例示している。第１周波数解析部３０３は、さらに、図３に示した全ての音線に対してこの作用を繰り返すことで、全方位に渡って第１スペクトルデータＳ（ｆ）を算出し、バッファ３０５へ出力する（以下、『方位』を、図３の全走査方向に渡り、超音波送受信方向として説明する）。 The RF data string F j (j = 1, 2, ..., K) shown in FIG. 4 is a portion of the RF data to be subjected to FFT processing. Generally, in order to perform FFT processing, the RF data string needs to have a power of 2 data number. In this sense, F K other RF data string F j (j = 1,2, ··· , K-1) is a normal RF data string by the number of data is 16 (= 2 4). On the other hand, the RF data string F K is an abnormal RF data string because the number of data is 12. When performing FFT processing on an abnormal RF data string, processing is performed to generate a normal RF data string by inserting zero data for the shortage. This point will be described in detail when the frequency analysis process is described (see FIG. 8). After that, the first frequency analysis unit 303 executes the FFT process as described above, calculates the frequency component V (f) of the voltage amplitude, and obtains the first spectrum data S (f) based on the above equation (1). ) Is calculated. After that, the first frequency analysis unit 303 changes the data position Z (k) with the step width D to calculate the first spectrum data S (f) at each position. Note that FIG. 4 illustrates the case where D = 15. The first frequency analysis unit 303 further repeats this action on all the sound lines shown in FIG. 3, calculates the first spectrum data S (f) in all directions, and outputs the first spectrum data S (f) to the buffer 305. (Hereinafter, the "direction" will be described as an ultrasonic transmission / reception direction over all scanning directions in FIG. 3).
　図１において前述した第２周波数解析部３０４は、第１周波数解析部３０３と同様にして、第２Ａ／Ｄコンバータ３０２が生成したＲＦデータにＦＦＴを施して周波数解析を行うことによって周波数スペクトルのデータ（以下、第２スペクトルデータという）を算出する。 In FIG. 1, the second frequency analysis unit 304 described above performs frequency analysis by applying FFT to the RF data generated by the second A / D converter 302 in the same manner as the first frequency analysis unit 303, thereby performing frequency spectrum data. (Hereinafter referred to as second spectrum data) is calculated.
　バッファ３０５は、第１周波数解析部３０３から入力された第１スペクトルデータを、一時的に記憶し、合成部３０７に出力する。
　バッファ３０６は、第２周波数解析部３０４から入力された第２スペクトルデータを、一時的に記憶し、合成部３０７に出力する。 The buffer 305 temporarily stores the first spectrum data input from the first frequency analysis unit 303 and outputs it to the synthesis unit 307.
The buffer 306 temporarily stores the second spectrum data input from the second frequency analysis unit 304 and outputs it to the synthesis unit 307.
　合成部３０７は、第１スペクトルデータと、第２スペクトルデータとを合成する。合成部３０７は、第１スペクトルデータと第２スペクトルデータとの被検体上の位置を一致させるための補正する位置補正部３０７ａを有する。位置補正部３０７ａは、超音波プローブ２から取得した位置補正データに基づいて、第１超音波振動子２１１と第２超音波振動子２１２との、フレキシブルシャフト２１４の回転角度によって生じる位置ずれを補正する。合成部３０７は、位置補正部３０７ａによって位置補正された第１スペクトルデータおよび第２スペクトルデータを合成する。具体的には、合成部３０７は、位置補正後の第１および第２スペクトルデータの線形表現を加算する。 The synthesis unit 307 synthesizes the first spectrum data and the second spectrum data. The synthesis unit 307 includes a position correction unit 307a for correcting the positions of the first spectrum data and the second spectrum data on the subject. The position correction unit 307a corrects the positional deviation caused by the rotation angle of the flexible shaft 214 between the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 based on the position correction data acquired from the ultrasonic probe 2. do. The synthesizing unit 307 synthesizes the first spectrum data and the second spectrum data whose position has been corrected by the position correction unit 307a. Specifically, the synthesis unit 307 adds the linear representations of the first and second spectrum data after the position correction.
　第１ログアンプ３０８は、入力される電圧振幅に対し、対数変換を行って、変換後の電圧振幅を出力する。対数変換では、エコー信号の振幅または強度を表すデータを、基準電圧と呼ばれる特定の電圧Ｖcで除し、さらにその常用対数をとることで変換する。変換後のデータはデシベル値で表現される（式（１）参照）。この音線データは、超音波パルスの後方散乱の強さを示すエコー信号の振幅または強度を１０進数で表現した桁に比例する値が、超音波パルスの送受信方向（深度方向）に沿って並んだデータである。 The first log amplifier 308 performs logarithmic conversion on the input voltage amplitude and outputs the converted voltage amplitude. In logarithmic conversion, data representing the amplitude or intensity of an echo signal is divided by a specific voltage V c called a reference voltage, and the common logarithm is taken for conversion. The converted data is represented by a decibel value (see equation (1)). In this sound line data, values proportional to the digit of the amplitude or intensity of the echo signal indicating the intensity of backward scattering of the ultrasonic pulse expressed in decimal numbers are arranged along the transmission / reception direction (depth direction) of the ultrasonic pulse. It is data.
　図５は、本発明の実施の形態１に係る超音波観測装置において用いられるスペクトルデータについて説明する図である。バッファ３０５、３０６を経由して合成部３０７に入力される第１スペクトルデータの線形表現をＶHO（ｆ）、第２スペクトルデータの線形表現をＶLO（ｆ）とすると、合成部３０７から出力される合成スペクトルデータの線形表現は、ＶHO（ｆ）＋ＶLO（ｆ）で表される。その後、第１ログアンプ３０８を通過した合成スペクトルデータは、ｄｂ表現として、２０・ｌｏｇ｛（ＶHO（ｆ）＋ＶLO（ｆ））／Ｖc｝で表される。ここで、スペクトルデータの線形表現は受信信号の振幅の周波数分布を表し、ｄＢ表現は線形表現の周波数分布の信号レベルを表す。 FIG. 5 is a diagram illustrating spectrum data used in the ultrasonic observation device according to the first embodiment of the present invention. Assuming that the linear representation of the first spectrum data input to the synthesis unit 307 via the buffers 305 and 306 is V HO (f) and the linear representation of the second spectrum data is V LO (f), the combination unit 307 outputs the data. The linear representation of the composite spectral data to be obtained is represented by V HO (f) + V LO (f). After that, the synthetic spectrum data that has passed through the first log amplifier 308 is represented by 20 log {(V HO (f) + V LO (f)) / V c } as a db representation. Here, the linear representation of the spectral data represents the frequency distribution of the amplitude of the received signal, and the dB representation represents the signal level of the frequency distribution of the linear representation.
　特徴量算出部３０９は、第１ログアンプ３０８から出力された合成スペクトルデータを直線で近似し、その直線を用いてスペクトルデータの特徴量を算出する。特徴量算出部３０９は、特徴量を第１座標変換部３１０へ出力する。 The feature amount calculation unit 309 approximates the composite spectrum data output from the first log amplifier 308 with a straight line, and calculates the feature amount of the spectrum data using the straight line. The feature amount calculation unit 309 outputs the feature amount to the first coordinate conversion unit 310.
　具体的には、特徴量算出部３０９は、所定周波数帯域における合成スペクトルデータの単回帰分析を行って合成スペクトルデータを一次式（回帰直線）で近似することによって、この近似した一次式を特徴付ける特徴量を算出する。単回帰分析とは、独立変数が１種類のみの場合の回帰分析である。本実施の形態での単回帰分析の独立変数は周波数ｆにあたる。 Specifically, the feature amount calculation unit 309 performs a simple regression analysis of the composite spectrum data in a predetermined frequency band and approximates the composite spectrum data with a linear equation (regression line) to characterize the approximated linear equation. Calculate the amount. The simple regression analysis is a regression analysis when there is only one type of independent variable. The independent variable of the simple regression analysis in this embodiment corresponds to the frequency f.
　図６Ａ～図６Ｃは、周波数スペクトルを用いた周波数特徴量の算出を説明するための図である。例えば、特徴量算出部３０９は、周波数帯域Ｕで単回帰分析を行い合成スペクトルデータＳSの回帰直線ＬSを得る（図６Ａ参照）。次に、特徴量算出部３０９は、回帰直線ＬSの傾きａ1、切片ｂ1、および周波数帯域Ｕの中心周波数（すなわち、「ミッドバンド」）ｆM＝（ｆL＋ｆH）／２の回帰直線上の値であるミッドバンドフィット（Mid-band　fit）ｃ1＝ａ1ｆM＋ｂ1を特徴量として算出する。回帰直線ＬSを特徴付ける一次式のパラメータ（傾きａ1、切片ｂ1、ミッドバンドフィットｃ1）で合成スペクトルデータＳSを表現することで、合成スペクトルデータＳSを一次式に近似したことになる。 6A to 6C are diagrams for explaining the calculation of the frequency feature amount using the frequency spectrum. For example, the feature amount calculation unit 309 performs a simple regression analysis in the frequency band U to obtain a regression line L S of the composite spectrum data S S (see FIG. 6A). Next, the feature amount calculating unit 309, the gradient a 1 of the regression line L S, the center frequency (i.e., "mid band") of the intercept b 1, and the frequency band U f M = the (f L + f H) / 2 The mid-band fit, which is a value on the regression line, is calculated as a feature amount of c 1 = a 1 f M + b 1. By expressing the composite spectrum data S S with the parameters of the linear equation (slope a 1 , intercept b 1 , midband fit c 1 ) that characterize the regression line L S , the composite spectrum data S S is approximated to the linear equation. Become.
　図１に戻り、周波数スペクトルのデータから算出される３つの特徴量のうち、傾きａ1、切片ｂ1は、超音波を散乱する散乱体の大きさ、散乱体の散乱強度、散乱体の数密度（濃度）等と相関を有していると考えられる。ミッドバンドフィットｃ1は、有効な周波数帯域内の中心におけるエコー信号の電圧振幅や強度を与える。このため、ミッドバンドフィットｃ1は、散乱体の大きさ、散乱体の散乱強度、散乱体の数密度に加えて、Ｂモード画像の輝度とある程度の相関を有していると考えられる。なお、特徴量算出部３０９は、回帰分析によって二次以上の多項式で周波数スペクトルのデータを近似してもよい。 Returning to Figure 1, of the three feature quantity calculated from the data of the frequency spectrum, the gradient a 1, the intercept b 1, the size of the scatterer which scatters ultrasound scattering intensity of the scattering bodies, the number of scatterers It is considered to have a correlation with the density (concentration) and the like. The midband fit c 1 provides the voltage amplitude and intensity of the echo signal at the center of the valid frequency band. Therefore, it is considered that the mid-band fit c 1 has a certain degree of correlation with the brightness of the B-mode image in addition to the size of the scatterer, the scattering intensity of the scatterer, and the number density of the scatterer. The feature amount calculation unit 309 may approximate the frequency spectrum data with a polynomial of degree 2 or higher by regression analysis.
　ここで、従来のスペクトルデータ、例えば図６Ｂに示す第２スペクトルデータＳ2を用いて特徴量を算出する場合、ノイズの影響によって理想の回帰直線と、実際に得られる回帰直線とには乖離が生じる。具体的には、図６Ｃに示すように、ノイズレベルと判定する振幅ｂ0以下の電圧振幅では、すべてが振幅ｂ0とされる場合がある（黒丸（●）参照）。この際、スペクトルデータの値がノイズレベル（黒丸）以下では振幅ｂ0となるため、図６Ｂに示す第２スペクトルデータＳ2の理想的な回帰直線Ｌ20とはならず、傾きや切片が異なる回帰直線Ｌ21となる。 Here, when the feature amount is calculated using the conventional spectrum data, for example, the second spectrum data S 2 shown in FIG. 6B, there is a discrepancy between the ideal regression line and the actually obtained regression line due to the influence of noise. Occurs. Specifically, as shown in FIG. 6C, all voltage amplitudes having an amplitude b 0 or less, which is determined to be a noise level, may be set to an amplitude b 0 (see the black circle (●)). At this time, when the value of the spectrum data is below the noise level (black circle), the amplitude b 0 , so that the ideal regression line L 20 of the second spectrum data S 2 shown in FIG. 6B is not obtained, and the slope and intercept are different. It becomes the regression line L 21.
　第１座標変換部３１０は、特徴量算出部３０９が算出した特徴量に応じて視覚情報を付与した特徴量画像データを生成する。具体的には、第１座標変換部３１０は、特徴量算出部３０９が算出した特徴量に関連する視覚情報をＢモード画像データにおける画像の各画素位置（座標）に対応して割り当てた特徴量画像データを生成する。視覚情報としては、例えば色相、彩度、明度、輝度値、Ｒ（赤）、Ｇ（緑）、Ｂ（青）などの所定の表色系を構成する色空間の変数を挙げることができる。次に、第１座標変換部３１０は、例えば図４に示す１つのＲＦデータストリングＦj（ｊ＝１、２、・・・、Ｋ）のデータ量に比例する深度長と、図３に示す音線間の方位間隔とで定義される画素領域に対し、そのＲＦデータストリングＦjから算出される特徴量に関連する視覚情報を割り当てる。 The first coordinate conversion unit 310 generates feature amount image data to which visual information is added according to the feature amount calculated by the feature amount calculation unit 309. Specifically, the first coordinate conversion unit 310 allocates visual information related to the feature amount calculated by the feature amount calculation unit 309 corresponding to each pixel position (coordinate) of the image in the B mode image data. Generate image data. Examples of the visual information include variables in the color space constituting a predetermined color system such as hue, saturation, brightness, luminance value, R (red), G (green), and B (blue). Next, the first coordinate conversion unit 310 shows, for example, a depth length proportional to the amount of data of one RF data string F j (j = 1, 2, ..., K) shown in FIG. 4 and a depth length shown in FIG. Visual information related to the feature amount calculated from the RF data string F j is assigned to the pixel region defined by the directional distance between the sound lines.
　本実施の形態１において、第１周波数解析部３０３、第２周波数解析部３０４、特徴量算出部３０９、第１座標変換部３１０は、走査領域Ｓ全体を解析範囲として処理する例を説明するが、解析範囲を、図３に示す走査領域Ｓのうち、特定の深度幅および方位幅（すなわち、走査方向の幅）などで区切られる関心領域（Region　of　Interest：ＲＯＩ）に限定して、上記の各処理を行ってもよい。関心領域を必要な領域に限定すれば、演算量を減らすことができ、表示するための速度を向上することができる。 In the first embodiment, an example will be described in which the first frequency analysis unit 303, the second frequency analysis unit 304, the feature amount calculation unit 309, and the first coordinate conversion unit 310 process the entire scanning region S as the analysis range. The analysis range is limited to the region of interest (Region of Interest: ROI) divided by a specific depth width and azimuth width (that is, the width in the scanning direction) in the scanning area S shown in FIG. Each process may be performed. By limiting the area of interest to the required area, the amount of calculation can be reduced and the speed for displaying can be improved.
　混合部３１１は、コントロールパネル５から入力される混合割合データに基づいて、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２からそれぞれ入力されるＲＦデータを混合する。混合部３１１は、混合後のＲＦデータを、第２ログアンプ３１２に出力する。 The mixing unit 311 mixes RF data input from the first A / D converter 301 and the second A / D converter 302, respectively, based on the mixing ratio data input from the control panel 5. The mixing unit 311 outputs the mixed RF data to the second log amplifier 312.
　第２ログアンプ３１２は、第１ログアンプ３０８と同様にして、入力される電圧振幅に対し、対数変換を行って、変換後の電圧振幅を出力する。 The second log amplifier 312 performs logarithmic conversion on the input voltage amplitude in the same manner as the first log amplifier 308, and outputs the converted voltage amplitude.
　包絡線検波部３１３は、第２ログアンプ３１２通過後のデータに対してバンドパスフィルタ、包絡線検波を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。 The envelope detection unit 313 applies a bandpass filter and an envelope detection to the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
　第２座標変換部３１５は、生成した音線データが走査範囲を空間的に正しく表現できるよう、音線データを並べ直す座標変換を施した後、音線データ間の補間処理を施すことによって音線データ間の空隙を埋め、Ｂモード画像データを生成する。Ｂモード画像は、色空間としてＲＧＢ表色系を採用した場合の変数であるＲ（赤）、Ｇ（緑）、Ｂ（青）の値を一致させたグレースケール画像である。第２座標変換部３１５は、生成したＢモード画像データを重畳部３１６へ出力する。なお、第２座標変換部３１５は、受信深度が大きいＲＦデータほど高い増幅率で増幅するＳＴＣ（Sensitivity　Time　Control）補正を行ってもよい。さらに、第２座標変換部３１５は、音線データに対してゲイン処理、コントラスト処理等の公知の技術を用いた信号処理を行ってもよい。 The second coordinate conversion unit 315 performs coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly, and then performs interpolation processing between the sound line data to produce sound. B-mode image data is generated by filling the gaps between the line data. The B-mode image is a grayscale image in which the values of R (red), G (green), and B (blue), which are variables when the RGB color system is adopted as the color space, are matched. The second coordinate conversion unit 315 outputs the generated B-mode image data to the superimposition unit 316. The second coordinate conversion unit 315 may perform STC (Sensitivity Time Control) correction that amplifies RF data having a larger reception depth with a higher amplification factor. Further, the second coordinate conversion unit 315 may perform signal processing on the sound line data using known techniques such as gain processing and contrast processing.
　重畳部３１６は、第２座標変換部３１５が生成したＢモード画像データ上に、第１座標変換部３１０が生成した特徴量画像データを重畳して、表示装置４に表示させる表示画像データを生成する。重畳部３１６は、コントロールパネル５から入力される重畳割合データに基づいて、Ｂモード画像の輝度と、特徴量の輝度とを調整することによって、Ｂモード画像データ上に特徴量画像データを重畳する。重畳部３１６は、表示画像データ生成部に相当する。 The superimposition unit 316 superimposes the feature amount image data generated by the first coordinate conversion unit 310 on the B mode image data generated by the second coordinate conversion unit 315, and generates display image data to be displayed on the display device 4. do. The superimposition unit 316 superimposes the feature amount image data on the B mode image data by adjusting the brightness of the B mode image and the brightness of the feature amount based on the superimposition ratio data input from the control panel 5. .. The superimposing unit 316 corresponds to a display image data generation unit.
　表示画像信号生成部３１７は、表示画像データに対応する画像（後述する重畳画像）を表示画面上の所定の位置に配置したり、表示装置４における画像の表示レンジに応じたデータの間引きや、階調処理などの所定の処理を施したりして、表示装置４に表示させる表示画像信号を生成する。表示画像信号生成部３１７は、生成した表示画像信号を表示装置４に出力して表示させる。 The display image signal generation unit 317 arranges an image corresponding to the display image data (superimposed image described later) at a predetermined position on the display screen, thins out the data according to the display range of the image on the display device 4, and performs the data thinning. A display image signal to be displayed on the display device 4 is generated by performing a predetermined process such as a gradation process. The display image signal generation unit 317 outputs the generated display image signal to the display device 4 for display.
　記憶部３１８は、各処理の演算パラメータやデータ等を記憶する。記憶部３１８は、接続される超音波プローブ２から位置補正データを取得して記憶する。記憶部３１８は、生成されたＢモード画像データや、周波数スペクトルデータ、特徴量画像データ等を記憶してもよい。周波数スペクトルデータは、第１スペクトルデータ、第２スペクトルデータおよび合成スペクトルデータの少なくとも一つを含む。記憶部３１８は、例えば、ＨＤＤ（Hard　Disk　Drive）や、ＳＤＲＡＭ（Synchronous　Dynamic　Random　Access　Memory）などを用いて構成される。 The storage unit 318 stores calculation parameters, data, etc. of each process. The storage unit 318 acquires and stores position correction data from the connected ultrasonic probe 2. The storage unit 318 may store the generated B-mode image data, frequency spectrum data, feature amount image data, and the like. The frequency spectrum data includes at least one of the first spectrum data, the second spectrum data, and the composite spectrum data. The storage unit 318 is configured by using, for example, an HDD (Hard Disk Drive) or an SDRAM (Synchronous Dynamic Random Access Memory).
　さらに、記憶部３１８は、上記以外にも、例えば各種処理に必要な情報、対数変換処理に必要な情報（式（１）参照、例えばα、Ｖcの値）、周波数解析処理に必要な窓関数（Hamming、Hanning、Blackman等）の情報等を記憶する。 Further, in addition to the above, the storage unit 318 includes, for example, information required for various processes, information required for logarithmic conversion processing (see equation (1), for example, values of α and V c ), and a window required for frequency analysis processing. Stores information such as functions (Hamming, Hanning, Blackman, etc.).
　また、記憶部３１８は、追加のメモリとして、超音波観測装置３の作動方法を実行するための作動プログラムを予めインストールした非一時的なコンピュータ読み取り可能な記録媒体、例えば図示しないＲＯＭ（Read　Only　Memory）を設けている。作動プログラムは、携帯型ハードディスク、フラッシュメモリ、ＣＤ－ＲＯＭ、ＤＶＤ－ＲＯＭ、フレキシブルディスク等のコンピュータ読み取り可能な記録媒体に記録して広く流通させることも可能である。なお、上述した各種プログラムは、通信ネットワークを経由してダウンロードすることによって取得することも可能である。ここでいう通信ネットワークは、例えば既存の公衆回線網、ＬＡＮ、ＷＡＮなどによって実現されるものであり、有線、無線を問わない。 Further, as an additional memory, the storage unit 318 is a non-temporary computer-readable recording medium in which an operation program for executing the operation method of the ultrasonic observation device 3 is pre-installed, for example, a ROM (Read Only Memory) (not shown). ) Is provided. The operation program can also be recorded on a computer-readable recording medium such as a portable hard disk, flash memory, CD-ROM, DVD-ROM, or flexible disk and widely distributed. The various programs described above can also be acquired by downloading them via a communication network. The communication network referred to here is realized by, for example, an existing public line network, LAN, WAN, etc., and may be wired or wireless.
　超音波観測装置３は、記憶部３１８が記憶、格納する作動プログラム等の情報や、各処理の演算パラメータ、データ等を記憶部３１８から読み出し、各部に作動方法に関連した各種演算処理を実行させることによって超音波観測装置３を統括して制御する。 The ultrasonic observation device 3 reads information such as an operation program stored and stored in the storage unit 318, calculation parameters of each process, data, etc. from the storage unit 318, and causes each unit to execute various calculation processes related to the operation method. As a result, the ultrasonic observation device 3 is controlled in an integrated manner.
　上述した第１周波数解析部３０３、第２周波数解析部３０４、合成部３０７、特徴量算出部３０９、第１座標変換部３１０、包絡線検波部３１３、第２座標変換部３１５、重畳部３１６および表示画像信号生成部３１７は、演算および制御機能を有するＣＰＵ（Central　Processing　Unit）等の汎用プロセッサ、またはＡＳＩＣ（Application　Specific　Integrated　Circuit）もしくはＦＰＧＡ（Field　Programmable　Gate　Array）等の特定の機能を実行する専用の集積回路等を用いて実現される。なお、上記のうち少なくとも一部を含む複数の部を共通の汎用プロセッサまたは専用の集積回路等を用いて構成することも可能である。 The first frequency analysis unit 303, the second frequency analysis unit 304, the synthesis unit 307, the feature amount calculation unit 309, the first coordinate conversion unit 310, the envelope detection unit 313, the second coordinate conversion unit 315, the superimposition unit 316, and the above-mentioned first frequency analysis unit 303, second frequency analysis unit 304, synthesis unit 307, and The display image signal generation unit 317 is dedicated to executing a general-purpose processor such as a CPU (Central Processing Unit) having arithmetic and control functions, or a specific function such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). It is realized by using the integrated circuit of. It is also possible to configure a plurality of parts including at least a part of the above by using a common general-purpose processor, a dedicated integrated circuit, or the like.
　コントロールパネル５は、各種の情報を入力可能な複数のボタンを用いて構成され、術者からの入力を受け付ける。コントロールパネル５には、第１つまみ５１と、第２つまみ５２とが設けられる。第１つまみ５１および第２つまみ５２は、各々が回転可能であり、回転位置に応じた操作信号を出力する。 The control panel 5 is configured by using a plurality of buttons capable of inputting various information, and accepts input from the operator. The control panel 5 is provided with a first knob 51 and a second knob 52. Each of the first knob 51 and the second knob 52 is rotatable and outputs an operation signal according to the rotation position.
　第１つまみ５１は、混合部３１１におけるＲＦデータの混合割合を入力する。例えば、第１つまみ５１の回転位置によって、第１Ａ／Ｄコンバータ３０１からのＲＦデータ（Ｈ）と、第２Ａ／Ｄコンバータ３０２からのＲＦデータ（Ｌ）との比（Ｈ：Ｌ）が設定されている。Ｈ：Ｌは、混合し得る割合に応じて１００：０、０：１００、５０：５０、７０：３０、・・・が設定される。 The first knob 51 inputs the mixing ratio of RF data in the mixing unit 311. For example, the ratio (H: L) of the RF data (H) from the first A / D converter 301 to the RF data (L) from the second A / D converter 302 is set according to the rotation position of the first knob 51. ing. H: L is set to 100: 0, 0: 100, 50:50, 70:30, ..., Depending on the ratio that can be mixed.
　第２つまみ５２は、重畳部３１６における特徴量画像データの重畳割合を入力する。例えば、第２つまみ５２の回転位置によって、第１座標変換部３１０からの特徴量画像データ（Ａ）と、第２座標変換部３１５からのＢモード画像データ（Ｂ）との比（Ａ：Ｂ）が設定されている。Ａ：Ｂは、重畳し得る割合に応じて１００：０、０：１００、５０：５０、７０：３０、・・・が設定される。 The second knob 52 inputs the superposition ratio of the feature amount image data in the superimposition unit 316. For example, depending on the rotation position of the second knob 52, the ratio (A: B) of the feature amount image data (A) from the first coordinate conversion unit 310 to the B mode image data (B) from the second coordinate conversion unit 315. ) Is set. For A: B, 100: 0, 0: 100, 50:50, 70:30, ... Are set according to the ratio that can be superimposed.
　コントロールパネル５は、表示画面を備えたタッチパネルがさらに設けられていてもよい。タッチパネルは、超音波画像や各種情報を表示することで、グラフィカルユーザインターフェース（ＧＵＩ）として機能する。タッチパネルとしては、抵抗膜方式、静電容量方式および光学方式等があり、いずれの方式のタッチパネルであっても適用可能である。 The control panel 5 may be further provided with a touch panel provided with a display screen. The touch panel functions as a graphical user interface (GUI) by displaying ultrasonic images and various information. The touch panel includes a resistive film method, a capacitance method, an optical method, and the like, and any type of touch panel can be applied.
　図７は、以上の構成を有する超音波観測装置３が行う処理の概要を示すフローチャートである。超音波観測装置３に超音波プローブ２が接続されると、超音波観測装置３は、超音波プローブ２から位置補正データを取得する（ステップＳ１０１）。また、この処理では、第１つまみ５１および第２つまみ５２から各種の割合データが入力されているものとして説明する。 FIG. 7 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3 having the above configuration. When the ultrasonic probe 2 is connected to the ultrasonic observation device 3, the ultrasonic observation device 3 acquires position correction data from the ultrasonic probe 2 (step S101). Further, in this process, it is assumed that various ratio data are input from the first knob 51 and the second knob 52.
　ステップＳ１０２において、人体内部の組織等、被検体に対する観測が始まると、第１超音波振動子２１１および第２超音波振動子２１２は被検体を走査し、被検体から受信したエコーを電気的なエコー信号へ変換する。第１Ａ／Ｄコンバータ３０１は、第１超音波振動子２１１を経由してエコー信号を受信する。第２Ａ／Ｄコンバータ３０２は、第２超音波振動子２１２を経由してエコー信号を受信する。各Ａ／Ｄコンバータは、そのエコー信号の必要に応じて増幅し、適当なサンプリング周波数（例えば５０ＭＨｚ）で増幅されたエコー信号をサンプリングして離散化してＲＦデータを生成する。第１Ａ／Ｄコンバータ３０１は、生成したＲＦデータを第１周波数解析部３０３へ出力する。第２Ａ／Ｄコンバータ３０２は、生成したＲＦデータを第２周波数解析部３０４へ出力する。 In step S102, when the observation of the subject such as the tissue inside the human body is started, the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 scan the subject and electrically transmit the echo received from the subject. Convert to echo signal. The first A / D converter 301 receives an echo signal via the first ultrasonic vibrator 211. The second A / D converter 302 receives the echo signal via the second ultrasonic transducer 212. Each A / D converter amplifies the echo signal as needed, samples the amplified echo signal at an appropriate sampling frequency (for example, 50 MHz), and disperses it to generate RF data. The first A / D converter 301 outputs the generated RF data to the first frequency analysis unit 303. The second A / D converter 302 outputs the generated RF data to the second frequency analysis unit 304.
　ステップＳ１０３からＳ１０７は、特徴量画像データ生成処理のフローである。
　ステップＳ１０３において、第１周波数解析部３０３および第２周波数解析部３０４は、ステップＳ１０２で生成されたＲＦデータから、周波数スペクトルデータをそれぞれ算出する。第１周波数解析部３０３は、各音線のＲＦデータ（ラインデータ）を比較的短い所定の時間間隔で複数に区切り、区切った各部分のＲＦデータにＦＦＴ演算による周波数解析を行うことによって全てのＲＦデータストリングに対する周波数スペクトルデータを算出する。 Steps S103 to S107 are the flow of the feature amount image data generation process.
In step S103, the first frequency analysis unit 303 and the second frequency analysis unit 304 calculate frequency spectrum data from the RF data generated in step S102, respectively. The first frequency analysis unit 303 divides the RF data (line data) of each sound line into a plurality of pieces at relatively short predetermined time intervals, and performs frequency analysis by FFT calculation on the RF data of each divided part. Calculate the frequency spectrum data for the RF data string.
　図８は、ステップＳ１０３において第１周波数解析部３０３および第２周波数解析部３０４が実行する処理の概要を示すフローチャートである。以下、図８に示すフローチャートを参照して、周波数解析処理を詳細に説明する。なお、この処理は、図４で述べた処理に基づいてフローにしたものである。以下の説明では、第１周波数解析部３０３が行う周波数解析処理について説明するが、第２周波数解析部３０４についても同様である。 FIG. 8 is a flowchart showing an outline of the processing executed by the first frequency analysis unit 303 and the second frequency analysis unit 304 in step S103. Hereinafter, the frequency analysis process will be described in detail with reference to the flowchart shown in FIG. It should be noted that this process is a flow based on the process described in FIG. In the following description, the frequency analysis process performed by the first frequency analysis unit 303 will be described, but the same applies to the second frequency analysis unit 304.
　ステップＳ２０１において、第１周波数解析部３０３は、解析対象の音線を識別するカウンタｋをｋ0とする。この初期値ｋ0は、図３中、解析範囲の最右の音線の番号である。 In step S201, the first frequency analysis unit 303 sets the counter k for identifying the sound line to be analyzed as k 0 . This initial value k 0 is the number of the rightmost sound line in the analysis range in FIG.
　ステップＳ２０２において、第１周波数解析部３０３は、ＦＦＴ演算用に取得する一連のＲＦデータストリングを代表するデータ位置（受信深度に対応）Ｚ(k)の初期値Ｚ(k) 0を設定する。 In step S202, the first frequency analysis unit 303 sets the initial value Z (k) 0 of the data position (corresponding to the reception depth) Z (k) representing a series of RF data strings acquired for the FFT calculation.
　その後、第１周波数解析部３０３は、ＲＦデータストリングを取得し（ステップＳ２０３）、取得したＲＦデータストリングに対し、記憶部３１８が記憶する窓関数を作用させる（ステップＳ２０４）。ＲＦデータストリングに対して窓関数を作用させることによって、ＲＦデータストリングが境界で不連続になることを回避し、アーチファクトが発生するのを防止することができる。 After that, the first frequency analysis unit 303 acquires the RF data string (step S203), and causes the window function stored by the storage unit 318 to act on the acquired RF data string (step S204). By acting a window function on the RF data string, it is possible to prevent the RF data string from becoming discontinuous at the boundary and prevent the occurrence of artifacts.
　続いて、第１周波数解析部３０３は、データ位置Ｚ(k)のＲＦデータストリングが正常なＲＦデータストリングであるか否かを判定する（ステップＳ２０５）。以下、正常なＲＦデータストリングのデータ数を２n（ｎは正の整数）とする。本実施の形態では、データ位置Ｚ(k)が、できるだけＺ(k)が属するＲＦデータストリングの中心になるよう設定される。具体的には、ＲＦデータストリングのデータ数は２nであるので、Ｚ(k)はそのＲＦデータストリングの中心に近い２n／２（＝２n-1）番目の位置に設定される。この場合、ＲＦデータストリングが正常であるとは、データ位置Ｚ(k)よりも浅い側に２n-1－１（＝Ｎとする）個のデータがあり、データ位置Ｚ(k)よりも深い側に２n-1（＝Ｍとする）個のデータがあることを意味する。 Subsequently, the first frequency analysis unit 303 determines whether or not the RF data string at the data position Z (k) is a normal RF data string (step S205). Hereinafter, the number of data in the normal RF data string is 2 n (n is a positive integer). In this embodiment, the data position Z (k) is set to be at the center of the RF data string to which Z (k) belongs as much as possible. Specifically, since the number of data in the RF data string is 2 n , Z (k) is set at the 2 n / 2 (= 2 n-1 ) th position near the center of the RF data string. In this case, the RF data string is normal, (a = N) 2 n-1 -1 to the shallower side than the data position Z (k) there are pieces of data, than the data position Z (k) It means that there are 2 n-1 (= M) data on the deep side.
　ステップＳ２０５における判定の結果、データ位置Ｚ(k)のＲＦデータストリングが正常である場合（ステップＳ２０５：Ｙｅｓ）、第１周波数解析部３０３は、後述するステップＳ２０７へ移行する。 As a result of the determination in step S205, when the RF data string at the data position Z (k) is normal (step S205: Yes), the first frequency analysis unit 303 shifts to step S207 described later.
　ステップＳ２０５における判定の結果、データ位置Ｚ(k)のＲＦデータストリングが正常でない場合（ステップＳ２０５：Ｎｏ）、第１周波数解析部３０３は、不足分だけゼロデータを挿入することによって正常なＲＦデータストリングを生成する（ステップＳ２０６）。ステップＳ２０６の後、第１周波数解析部３０３は、後述するステップＳ２０７へ移行する。 As a result of the determination in step S205, when the RF data string at the data position Z (k) is not normal (step S205: No), the first frequency analysis unit 303 inserts zero data for the shortage to obtain normal RF data. Generate a string (step S206). After step S206, the first frequency analysis unit 303 shifts to step S207, which will be described later.
　ステップＳ２０７において、第１周波数解析部３０３は、ＲＦデータストリングにＦＦＴ演算を施すことによって、エコー信号の電圧振幅の周波数分布に相当するＶ（ｆ）を算出する。その後、第１周波数解析部３０３は、Ｖ(ｆ）に対数変換処理を施して、周波数スペクトルデータＳ（ｆ）を得る（ステップＳ２０７）。 In step S207, the first frequency analysis unit 303 calculates V (f) corresponding to the frequency distribution of the voltage amplitude of the echo signal by performing an FFT calculation on the RF data string. After that, the first frequency analysis unit 303 performs logarithmic conversion processing on V (f) to obtain frequency spectrum data S (f) (step S207).
　ステップＳ２０８において、第１周波数解析部３０３は、データ位置Ｚ(k)をステップ幅Ｄで変化させる。 In step S208, the first frequency analysis unit 303 changes the data position Z (k) with the step width D.
　その後、第１周波数解析部３０３は、データ位置Ｚ(k)が音線ＳＲkにおける最大値Ｚ(k) maxよりも大きいか否かを判定する（ステップＳ２０９）。データ位置Ｚ(k)が最大値Ｚ(k) maxよりも大きい場合（ステップＳ２０９：Ｙｅｓ）、第１周波数解析部３０３はカウンタｋを１増加させる（ステップＳ２１０）。これは、処理をとなりの音線へ移すことを意味する。一方、データ位置Ｚ(k)が最大値Ｚ(k) max以下である場合（ステップＳ２０９：Ｎｏ）、第１周波数解析部３０３はステップＳ２０３へ戻る。 After that, the first frequency analysis unit 303 determines whether or not the data position Z (k) is larger than the maximum value Z (k) max in the sound line SR k (step S209). When the data position Z (k) is larger than the maximum value Z (k) max (step S209: Yes), the first frequency analysis unit 303 increments the counter k by 1 (step S210). This means that the processing is transferred to the next sound line. On the other hand, when the data position Z (k) is equal to or less than the maximum value Z (k) max (step S209: No), the first frequency analysis unit 303 returns to step S203.
　ステップＳ２１０の後、第１周波数解析部３０３は、カウンタｋが最大値ｋmaxよりも大きいか否かを判定する（ステップＳ２１１）。カウンタｋがｋmaxよりも大きい場合（ステップＳ２１１：Ｙｅｓ）、第１周波数解析部３０３は一連の周波数解析処理を終了する。一方、カウンタｋがｋmax以下である場合（ステップＳ２１１：Ｎｏ）、第１周波数解析部３０３はステップＳ２０２に戻る。 After step S210, the first frequency analysis unit 303 determines whether or not the counter k is larger than the maximum value k max (step S211). When the counter k is larger than k max (step S211: Yes), the first frequency analysis unit 303 ends a series of frequency analysis processes. On the other hand, when the counter k is k max or less (step S211: No), the first frequency analysis unit 303 returns to step S202.
　再び図４において、第１周波数解析部３０３は、解析対象領域内の（ｋmax－ｋ0＋１）本の音線の各々について深度別に複数回のＦＦＴ演算を行う。ＦＦＴ演算の結果は、受信深度および受信方向とともに記憶部３１８に格納される。 Again, in FIG. 4, the first frequency analysis unit 303 performs a plurality of FFT calculations for each of the (k max −k 0 + 1) sound lines in the analysis target region for each depth. The result of the FFT calculation is stored in the storage unit 318 together with the reception depth and the reception direction.
　なお、これら４種の値ｋ0、ｋmax、Ｚ(k) 0、Ｚ(k) maxについては、図３の全走査範囲を含むようなデフォルト値が記憶部３１８にあらかじめ記憶されており、第１周波数解析部３０３は適宜これらの値を読み取って、図８の処理を行う。デフォルト値を読み取った場合、第１周波数解析部３０３は全走査範囲に対して周波数解析処理を行う。しかし、この４種の値ｋ0、ｋmax、Ｚ(k) 0、Ｚ(k) maxは、コントロールパネル５を経由した術者による関心領域の指示入力によって変更可能である。変更されていた場合、第１周波数解析部３０３は指示入力された関心領域においてのみ周波数解析処理を行う。 Regarding these four values, k 0 , k max , Z (k) 0 , and Z (k) max , default values including the entire scanning range of FIG. 3 are stored in advance in the storage unit 318. The first frequency analysis unit 303 appropriately reads these values and performs the processing of FIG. When the default value is read, the first frequency analysis unit 303 performs frequency analysis processing on the entire scanning range. However, these four values, k 0 , k max , Z (k) 0 , and Z (k) max , can be changed by inputting an instruction of the region of interest by the operator via the control panel 5. If it has been changed, the first frequency analysis unit 303 performs the frequency analysis process only in the region of interest in which the instruction is input.
　再び、図７を参照して説明する。ステップＳ１０４において、合成部３０７は、第１スペクトルデータと、第２スペクトルデータとを合成する。具体的には、合成部３０７は、位置補正部３０７ａによって第１スペクトルデータと第２スペクトルデータとの被検体上の位置を一致させるための補正し、位置補正された第１スペクトルデータおよび第２スペクトルデータを合成する。 It will be explained again with reference to FIG. 7. In step S104, the synthesis unit 307 synthesizes the first spectrum data and the second spectrum data. Specifically, the synthesis unit 307 is corrected by the position correction unit 307a to match the positions of the first spectrum data and the second spectrum data on the subject, and the position-corrected first spectrum data and the second spectrum data are present. Synthesize spectral data.
　ステップＳ１０５において、第１ログアンプ３０８は、入力される電圧振幅に対し、対数変換を行う。第１ログアンプ３０８は、変換後の電圧振幅を特徴量算出部３０９に出力する。 In step S105, the first log amplifier 308 performs logarithmic conversion with respect to the input voltage amplitude. The first log amplifier 308 outputs the converted voltage amplitude to the feature amount calculation unit 309.
　ステップＳ１０６において、特徴量算出部３０９は、第１ログアンプ３０８から出力された合成スペクトルデータを直線で近似し、その直線を用いてスペクトルデータの特徴量を算出する。特徴量算出部３０９は、例えば、上述した回帰直線ＬSの傾きａ1、切片ｂ1、およびミッドバンドフィットｃ1のうち、指定された特徴量を算出する。 In step S106, the feature amount calculation unit 309 approximates the composite spectrum data output from the first log amplifier 308 with a straight line, and calculates the feature amount of the spectrum data using the straight line. Feature amount calculation unit 309, for example, the gradient a 1 of the regression line L S described above, the intercept b 1, and of the mid-band fit c 1, calculates the specified characteristic quantity.
　ステップＳ１０７において、第１座標変換部３１０は、特徴量算出部３０９が算出した特徴量に応じて視覚情報を付与した特徴量画像データを生成する。 In step S107, the first coordinate conversion unit 310 generates feature image data to which visual information is added according to the feature calculated by the feature calculation unit 309.
　ステップＳ１０３と並行して、混合部３１１は、第１つまみ５１から入力される混合割合データに基づいて、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２からそれぞれ入力されるＲＦデータを混合する（ステップＳ１０８）。 In parallel with step S103, the mixing unit 311 mixes the RF data input from the first A / D converter 301 and the second A / D converter 302, respectively, based on the mixing ratio data input from the first knob 51. (Step S108).
　Ｓ１０８からＳ１１１は、Ｂモード画像生成処理のフローである。
　ステップＳ１０９において、第２ログアンプ３１２は、第１ログアンプ３０８と同様にして、入力される電圧振幅に対し、対数変換を行う。第２ログアンプ３１２は、変換後の電圧振幅を包絡線検波部３１３に出力する。 S108 to S111 are flows of B-mode image generation processing.
In step S109, the second log amplifier 312 performs logarithmic conversion with respect to the input voltage amplitude in the same manner as the first log amplifier 308. The second log amplifier 312 outputs the converted voltage amplitude to the envelope detection unit 313.
　ステップＳ１１０において、包絡線検波部３１３は、第２ログアンプ３１２通過後のデータに対して包絡線検波等を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。 In step S110, the envelope detection unit 313 performs envelope detection or the like on the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
　ステップＳ１１１において、第２座標変換部３１５は、生成した音線データが走査範囲を空間的に正しく表現できるよう、音線データを並べ直す座標変換を施してＢモード画像データを生成する。 In step S111, the second coordinate conversion unit 315 performs coordinate conversion to rearrange the sound line data so that the generated sound line data can express the scanning range spatially correctly, and generates B mode image data.
　ここで、ステップＳ１０３～Ｓ１０７までの特徴量画像データ生成処理と、ステップＳ１０８～Ｓ１１１までのＢモード画像生成処理とは、同時に行ってもよいし、一方を先に行ってもよい。 Here, the feature amount image data generation processing in steps S103 to S107 and the B-mode image generation processing in steps S108 to S111 may be performed at the same time, or one of them may be performed first.
　ステップＳ１１２において、重畳部３１６は、第２つまみ５２から入力される重畳割合データに基づいて、Ｂモード画像データ上に特徴量画像データを重畳して、表示装置４に表示させる表示画像データを生成する。また、重畳部３１６は、Ｂモード画像データを表示画像信号生成部３１７に出力する。 In step S112, the superimposition unit 316 superimposes the feature amount image data on the B mode image data based on the superimposition ratio data input from the second knob 52, and generates display image data to be displayed on the display device 4. do. Further, the superimposition unit 316 outputs the B mode image data to the display image signal generation unit 317.
　ステップＳ１１３において、表示画像信号生成部３１７は、重畳部３１６が生成した表示画像データや、Ｂモード画像データに対して、表示装置４における画像の表示レンジに応じたデータの間引きや、階調処理などの所定の処理を施して表示画像信号を生成し、表示装置４に出力して表示させる。 In step S113, the display image signal generation unit 317 thins out the display image data generated by the superimposition unit 316 and the B-mode image data according to the display range of the image in the display device 4, and performs gradation processing. A display image signal is generated by performing a predetermined process such as, and is output to the display device 4 for display.
　図９に、超音波信号に基づいて生成された表示画像データに対応する画像の表示例示す。表示装置４の表示画面Ｗには、特徴量画像が重畳されていないＢモード画像Ｗ1と、特徴量画像がＢモード画像に重畳された重畳画像Ｗ2とが表示される。 FIG. 9 shows a display example of an image corresponding to the display image data generated based on the ultrasonic signal. The display screen W of the display device 4, a B-mode image W 1 to the feature amount image is not superimposed, the feature quantity image and superposed image W 2 superimposed is displayed on the B-mode image.
　続いて、超音波プローブ２における位置補正データの設定の一例について、図１０～図１２を参照して説明する。図１０～図１２は、超音波プローブ２が記憶する位置補正データの設定について説明する図である。位置補正データは、例えば、工場における超音波プローブ２の出荷時に取得される。 Subsequently, an example of setting the position correction data in the ultrasonic probe 2 will be described with reference to FIGS. 10 to 12. 10 to 12 are views for explaining the setting of the position correction data stored in the ultrasonic probe 2. The position correction data is acquired, for example, at the time of shipment of the ultrasonic probe 2 in the factory.
　位置補正データは、図１０に示すテグス１００の超音波画像（Ｂモード画像）を取得して生成する。エコー信号は、フレキシブルシャフト２１４を回転させて、第１超音波振動子２１１および第２超音波振動子２１２を同時に回転駆動させながら、第１超音波振動子２１１および第２超音波振動子２１２を走査してエコー信号をそれぞれ取得する。第１超音波振動子２１１および第２超音波振動子２１２によって、走査面ＰSにおけるテグス１００の像を含むＢモード画像を取得する。 The position correction data is generated by acquiring an ultrasonic image (B mode image) of the Tegs 100 shown in FIG. The echo signal causes the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212 while rotating the flexible shaft 214 and simultaneously rotating and driving the first ultrasonic vibrator 211 and the second ultrasonic vibrator 212. Scan to obtain each echo signal. The first ultrasonic transducer 211 and the second ultrasonic transducer 212, to obtain the B-mode image including the image of the gut 100 at the scanning plane P S.
　位置補正データの設定時、超音波プローブ２は、工場用の超音波観測装置６に接続される（図１１参照）。超音波観測装置６では、取得したエコー信号に基づいてＢモード画像が生成される。生成されたＢモード画像は、モニタ６１に表示される。モニタ６１には、第１超音波振動子２１１および第２超音波振動子２１２の各エコー信号に基づくＢモード画像を重ね合わせたＢモード重畳画像ＷBSや、いずれかのエコー信号に基づくＢモード画像が表示される。 When setting the position correction data, the ultrasonic probe 2 is connected to the ultrasonic observation device 6 for a factory (see FIG. 11). The ultrasonic observation device 6 generates a B-mode image based on the acquired echo signal. The generated B-mode image is displayed on the monitor 61. The monitor 61, B-mode and the superimposed image W BS superimposed B-mode image based on echo signals of the first ultrasonic transducer 211 and the second ultrasonic transducer 212, B-mode based on either the echo signal The image is displayed.
　また、超音波観測装置６には、コントロールパネル７が接続される。コントロールパネル７には、位置補正データの記憶部２２１への書き込みを指示する書込指示ボタン７１と、互いに反対方向への回転の指示を入力する回転指示ボタン７２、７３とが設けられる。 Further, the control panel 7 is connected to the ultrasonic observation device 6. The control panel 7 is provided with a writing instruction button 71 for instructing writing of position correction data to the storage unit 221 and rotation instruction buttons 72 and 73 for inputting rotation instructions in opposite directions.
　ここで、第１超音波振動子２１１が取得したエコー信号に基づくＢモード画像をＷBH、このＢモード画像ＷBHにおけるテグス像をＱHとする。また、第２超音波振動子２１２が取得したエコー信号に基づくＢモード画像をＷBL、このＢモード画像ＷBLにおけるテグス像をＱLとする。第１超音波振動子２１１および第２超音波振動子２１２がバッキング材２１３に対して互いに反対側に接着されている場合、Ｂモード重畳画像ＷBSにおいて、テグス像ＱHとテグス像ＱLとは、中心エコーＱ0に対して反対側に位置する（例えば図１１のＢモード重畳画像ＷBSを参照）。 Here, the B-mode image based on the first echo signal by the ultrasonic transducer 211 has acquired W BH, the gut image in the B-mode image W BH and Q H. Further, the B mode image based on the echo signal acquired by the second ultrasonic vibrator 212 is referred to as W BL , and the Tegs image in this B mode image W BL is referred to as Q L. If the first ultrasonic transducer 211 and the second ultrasonic transducer 212 is bonded to the opposite side each other with respect to the backing material 213, in the B-mode superimposed image W BS, and guts image Q H and gut image Q L is positioned on the opposite side with respect to the center echo Q 0 (see B-mode superimposed image W BS in FIG. 11 for example).
　ユーザは、Ｂモード重畳画像ＷBSにおいて、回転指示ボタン７２、７３の押下によって、中心エコーＱ0を中心にＢモード画像ＷBHを回転させ、テグス像ＱHとテグス像ＱLとを一致させる（図１２参照）。テグス像ＱHとテグス像ＱLとが一致した際のＢモード画像ＷBHの回転角度θが、位置補正データとして設定される。テグス像ＱHとテグス像ＱLとが一致して、ユーザによって書込指示ボタン７１が押下されると、超音波観測装置６は、その際の回転角度を、位置補正データとして超音波プローブ２の記憶部２２１に書き込む。 The user, in the B-mode superimposed image W BS, upon depression of the rotation instruction buttons 72 and 73, about the center echoes Q 0 by rotating the B-mode image W BH, to match the gut image Q H and gut image Q L (See FIG. 12). The rotation angle θ of the B mode image W BH when the Tegs image Q H and the Tegs image Q L match is set as the position correction data. When the Tegs image Q H and the Tegs image Q L match and the write instruction button 71 is pressed by the user, the ultrasonic observation device 6 uses the rotation angle at that time as position correction data for the ultrasonic probe 2. Write to the storage unit 221 of.
　以上説明した本発明の実施の形態１では、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを用いて、特徴量を算出する。特徴量算出部３０９では、十分な周波数帯域において回帰直線を求めることができる。これは、高周波のエコー信号のみ、または低周波のエコー信号のみを用いて回帰直線を求める場合と比して、特徴量を精度よく算出することができる。本実施の形態１によれば、高精度に特徴量を算出することによって、組織間の微妙な相違を鑑別しやすくなる。 In the first embodiment of the present invention described above, the feature amount is calculated using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal. The feature amount calculation unit 309 can obtain a regression line in a sufficient frequency band. This makes it possible to calculate the feature amount more accurately than in the case of obtaining the regression line using only the high-frequency echo signal or only the low-frequency echo signal. According to the first embodiment, by calculating the feature amount with high accuracy, it becomes easy to distinguish a subtle difference between tissues.
　なお、第１スペクトルデータＳ1および第２スペクトルデータＳ2と、合成スペクトルデータＳSとでは、得られる特徴量の絶対値が変わってしまう。しかしながら、機器を用いた診断の際には、正常な組織などのリファレンスの色として青を割り当て、絶対値ではなく対象組織とリファレンスとの差である相対値に適切な色を割り当てられることが多い。本実施の形態１では、従来と比して、組織間の微妙な差異を見分けやすくなる分、鑑別には有利である。 The absolute value of the obtained feature amount is different between the first spectrum data S 1 and the second spectrum data S 2 and the synthetic spectrum data S S. However, when diagnosing with a device, blue is often assigned as the reference color for normal tissues, and an appropriate color is often assigned to the relative value, which is the difference between the target tissue and the reference, rather than the absolute value. .. In the first embodiment, it is easier to distinguish subtle differences between tissues as compared with the conventional case, which is advantageous for discrimination.
　また、本発明の実施の形態１によれば、超音波プローブ２の製造時の誤差を補正する位置補正データを、超音波プローブ２から読み出す構成のため、第１超音波振動子２１１および第２超音波振動子２１２をバッキング材２１３に接着した際などに生じるずれを補正できる。 Further, according to the first embodiment of the present invention, since the position correction data for correcting the error in the manufacturing of the ultrasonic probe 2 is read from the ultrasonic probe 2, the first ultrasonic vibrator 211 and the second ultrasonic transducer 211 are used. It is possible to correct the deviation that occurs when the ultrasonic vibrator 212 is attached to the backing material 213.
　なお、本実施の形態１において、位置補正部３０７ａは、合成部３０７の中に設けられているものとして説明したが、合成部３０７とは別に設けられるものであってもよい。 Although the position correction unit 307a has been described as being provided in the synthesis unit 307 in the first embodiment, it may be provided separately from the composition unit 307.
　また、本実施の形態１において、位置補正データは、Ｂモード画像ＷBLに対するＢモード画像ＷBHの回転角度である例を説明したが、これに限らない。位置補正データは、例えば、中心エコーからの音線方向における超音波振動子のずれ（フレキシブルシャフト２１４からの距離（差））としてもよい。 Further, in the first embodiment, the example in which the position correction data is the rotation angle of the B mode image W BH with respect to the B mode image W BL has been described, but the present invention is not limited to this. The position correction data may be, for example, a deviation of the ultrasonic vibrator in the sound line direction from the central echo (distance (difference) from the flexible shaft 214).
　また、本実施の形態１において、互いに異なる周波数特性を有する超音波振動子を二つ有する例を説明したが、これに限らず、三つ以上の超音波振動子を設けてもよい。 Further, in the first embodiment, an example in which two ultrasonic vibrators having different frequency characteristics are described has been described, but the present invention is not limited to this, and three or more ultrasonic vibrators may be provided.
（実施の形態２）
　続いて、本発明の実施の形態２について説明する。図１３は、本発明の実施の形態２に係る超音波内視鏡の要部の構成を説明する図である。実施の形態２は、上述した実施の形態１に対し、超音波内視鏡の挿入部２１の構成が異なる。以下、実施の形態２に係る超音波内視鏡の挿入部２１Ａの構成について、説明する。 (Embodiment 2)
Subsequently, a second embodiment of the present invention will be described. FIG. 13 is a diagram illustrating a configuration of a main part of an ultrasonic endoscope according to a second embodiment of the present invention. The second embodiment is different from the first embodiment described above in that the insertion portion 21 of the ultrasonic endoscope is configured. Hereinafter, the configuration of the insertion portion 21A of the ultrasonic endoscope according to the second embodiment will be described.
　挿入部２１Ａは、その先端部に、超音波観測装置３から受信した電気的なパルス信号を超音波パルス（音響パルス）に変換して被検体へ照射するとともに、被検体で後方散乱された超音波エコーを電圧変化で表現する電気的なエコー信号に変換する超音波振動子２１５と、光学レンズ２１６と、撮像素子（図示せず）とを有する。実施の形態２では、超音波プローブとして、超音波内視鏡が用いられる。超音波内視鏡は、挿入部２１Ａの先端部に、撮像用の光学レンズおよび撮像素子をさらに有する。 The insertion portion 21A converts an electrical pulse signal received from the ultrasonic observation device 3 into an ultrasonic pulse (acoustic pulse) and irradiates the subject with the tip portion thereof, and at the same time, the ultrasonic pulse is scattered backward by the subject. It has an ultrasonic vibrator 215 that converts an ultrasonic echo into an electrical echo signal expressed by a voltage change, an optical lens 216, and an image pickup element (not shown). In the second embodiment, an ultrasonic endoscope is used as the ultrasonic probe. The ultrasonic endoscope further has an optical lens for imaging and an image pickup element at the tip portion of the insertion portion 21A.
　超音波振動子２１５は、複数の第１振動子部２１５ａと、複数の第２振動子部２１５ｂとを有する。第１振動子部２１５ａおよび第２振動子部２１５ｂは、互いに異なる周波数特性の超音波ビームを送信する圧電素子からなる。第１振動子部２１５ａおよび第２振動子部２１５ｂは、挿入部２１Ａの周方向に、交互に配置される。なお、図１３中、第２振動子部２１５ｂには、第１振動子部２１５ａとの区別のためにハッチングを付している。 The ultrasonic vibrator 215 has a plurality of first vibrators 215a and a plurality of second vibrators 215b. The first vibrator unit 215a and the second vibrator unit 215b are composed of piezoelectric elements that transmit ultrasonic beams having different frequency characteristics from each other. The first vibrator portion 215a and the second vibrator portion 215b are alternately arranged in the circumferential direction of the insertion portion 21A. In FIG. 13, the second vibrator portion 215b is hatched to distinguish it from the first vibrator portion 215a.
　超音波振動子２１５は、超音波観測装置３の制御のもと、第１振動子部２１５ａと第２振動子部２１５ｂとが交互に駆動するラジアル型の電子式超音波振動子である。例えば、高周波のエコー信号を取得する場合には各第１振動子部２１５ａが駆動し、低周波のエコー信号を取得する場合には各第２振動子部２１５ｂが駆動する。受信したエコー信号は超音波観測装置３に出力され、実施の形態１と同様にして処理される。また、撮像素子が撮像した画像信号は、図示しない撮像処理装置に出力され、撮像処理装置内の図示しない画像処理回路によって撮像画像データが生成、表示される。 The ultrasonic vibrator 215 is a radial type electronic ultrasonic vibrator in which the first vibrator portion 215a and the second vibrator portion 215b are alternately driven under the control of the ultrasonic observation device 3. For example, when acquiring a high-frequency echo signal, each first oscillator unit 215a is driven, and when acquiring a low-frequency echo signal, each second oscillator unit 215b is driven. The received echo signal is output to the ultrasonic observation device 3 and processed in the same manner as in the first embodiment. Further, the image signal captured by the image sensor is output to an image processing device (not shown), and the captured image data is generated and displayed by an image processing circuit (not shown) in the image processing device.
　以上説明した本発明の実施の形態２では、超音波振動子の切り替えを機械的な駆動機構を必要としない超音波プローブ（超音波内視鏡）において、実施の形態１と同様に、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを用いて、特徴量を精度よく算出することができる。本実施の形態２によれば、高精度に特徴量を算出することによって、組織間の微妙な相違を鑑別しやすくなる。 In the second embodiment of the present invention described above, the switching of the ultrasonic vibrator is different from each other in the ultrasonic probe (ultrasonic endoscope) which does not require a mechanical drive mechanism, as in the first embodiment. The feature amount can be calculated accurately by using the high-frequency echo signal received from the ultrasonic vibrator having the frequency characteristics and the low-frequency echo signal. According to the second embodiment, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
（実施の形態２の変形例）
　続いて、本発明の実施の形態２の変形例について説明する。図１４は、本発明の実施の形態２の変形例に係る超音波プローブの要部の構成を説明する図である。 (Modified Example of Embodiment 2)
Subsequently, a modified example of the second embodiment of the present invention will be described. FIG. 14 is a diagram illustrating a configuration of a main part of an ultrasonic probe according to a modified example of the second embodiment of the present invention.
　変形例に係る挿入部２１Ｂは、その先端部に、超音波観測装置３から受信した電気的なパルス信号を超音波パルス（音響パルス）に変換して被検体へ照射するとともに、被検体で後方散乱された超音波エコーを電圧変化で表現する電気的なエコー信号に変換する超音波振動子２１７と、光学レンズ２１８と、撮像素子（図示せず）とを有する。 The insertion portion 21B according to the modified example converts an electrical pulse signal received from the ultrasonic observation device 3 into an ultrasonic pulse (acoustic pulse) and irradiates the subject at the tip thereof, and at the same time, rearward the subject. It includes an ultrasonic vibrator 217 that converts scattered ultrasonic echoes into an electrical echo signal expressed by a voltage change, an optical lens 218, and an image pickup element (not shown).
　超音波振動子２１７は、複数の第１振動子部２１７ａと、複数の第２振動子部２１７ｂとを有する。第１振動子部２１７ａおよび第２振動子部２１７ｂは、互いに異なる周波数特性の超音波ビームを送信する圧電素子からなる。第１振動子部２１７ａおよび第２振動子部２１７ｂは、挿入部２１Ｂの長手方向に、交互に配置され、曲面をなす外表面を形成する。なお、図１４中、第２振動子部２１７ｂには、第１振動子部２１７ａとの区別のためにハッチングを付している。また、超音波振動子２１７は、実際の振動子の厚み、及び、厚み方向の構造とは異なり、説明上、振動子の厚みを強調したモデルの画像として示した。 The ultrasonic vibrator 217 has a plurality of first vibrators 217a and a plurality of second vibrators 217b. The first vibrator unit 217a and the second vibrator unit 217b are composed of piezoelectric elements that transmit ultrasonic beams having different frequency characteristics from each other. The first vibrator portion 217a and the second vibrator portion 217b are alternately arranged in the longitudinal direction of the insertion portion 21B to form a curved outer surface. In FIG. 14, the second vibrator portion 217b is hatched to distinguish it from the first vibrator portion 217a. Further, the ultrasonic vibrator 217 is shown as an image of a model in which the thickness of the vibrator is emphasized for explanation, unlike the actual thickness of the vibrator and the structure in the thickness direction.
　超音波振動子２１７は、超音波観測装置３の制御のもと、第１振動子部２１７ａと第２振動子部２１７ｂとが交互に駆動するコンベックス型の電子式超音波振動子である。例えば、高周波のエコー信号を取得する場合には各第１振動子部２１７ａが駆動し、低周波のエコー信号を取得する場合には各第２振動子部２１７ｂが駆動する。受信したエコー信号は超音波観測装置３に出力され、実施の形態１と同様にして処理される。 The ultrasonic vibrator 217 is a convex type electronic ultrasonic vibrator in which the first vibrator portion 217a and the second vibrator portion 217b are alternately driven under the control of the ultrasonic observation device 3. For example, when acquiring a high-frequency echo signal, each first oscillator unit 217a is driven, and when acquiring a low-frequency echo signal, each second oscillator unit 217b is driven. The received echo signal is output to the ultrasonic observation device 3 and processed in the same manner as in the first embodiment.
　以上説明した変形例においても、実施の形態１、２と同様に、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを用いて、特徴量を算出するため、特徴量を精度よく算出することができる。本変形例によれば、高精度に特徴量を算出することによって、組織間の微妙な相違を鑑別しやすくなる。 Also in the modification described above, the feature amount is determined by using the high frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low frequency echo signal as in the first and second embodiments. Since it is calculated, the feature amount can be calculated accurately. According to this modified example, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
（実施の形態３）
　続いて、本発明の実施の形態３について説明する。図１５は、本発明の実施の形態３に係る超音波観測装置３Ａを備えた超音波診断システム１Ａの構成を示すブロック図である。上述した実施の形態１と同じ構成には同じ符号を付し、実施の形態１で説明したものと同じ機能を有する。 (Embodiment 3)
Subsequently, the third embodiment of the present invention will be described. FIG. 15 is a block diagram showing a configuration of an ultrasonic diagnostic system 1A including the ultrasonic observation device 3A according to the third embodiment of the present invention. The same configurations as those described in the first embodiment are designated by the same reference numerals and have the same functions as those described in the first embodiment.
　本実施の形態３に係る超音波診断システム１Ａは、上述した実施の形態１に係る超音波診断システム１の構成に対し、超音波観測装置３に代えて超音波観測装置３Ａを備え、コントロールパネル５に代えてコントロールパネル５Ａを備える。実施の形態１の超音波診断装置３と異なる構成として、切替選択つまみ５３、第３周波数解析部３１９、第１ログアンプ３２０、第１包絡線検波部３２１、バッファ３２２、第１座標変換部３２３、切替スイッチ３２４、第２包絡線検波部３２５、および、表示画像データ生成部３２６を備える。 The ultrasonic diagnostic system 1A according to the third embodiment includes an ultrasonic observation device 3A instead of the ultrasonic observation device 3 for the configuration of the ultrasonic diagnostic system 1 according to the first embodiment described above, and is a control panel. A control panel 5A is provided instead of 5. As a configuration different from the ultrasonic diagnostic apparatus 3 of the first embodiment, the switching selection knob 53, the third frequency analysis unit 319, the first log amplifier 320, the first envelope detection unit 321 and the buffer 322, and the first coordinate conversion unit 323 , A changeover switch 324, a second envelope detection unit 325, and a display image data generation unit 326.
　第３周波数解析部３１９は、合成部３０７からの合成スペクトルデータに対し、逆ＦＦＴを施す。第３周波数解析部３１９の処理によって生成されるデータは、合成スペクトルデータが、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２から出力されるＲＦデータの合成データに相当する。 The third frequency analysis unit 319 performs an inverse FFT on the composite spectrum data from the synthesis unit 307. The data generated by the processing of the third frequency analysis unit 319 corresponds to the composite data of the RF data whose composite spectrum data is output from the first A / D converter 301 and the second A / D converter 302.
　第１ログアンプ３２０は、第１ログアンプ３０８と同様にして、入力される電圧振幅に対し、対数変換を行って、変換後の電圧振幅を出力する。 The first log amplifier 320 performs logarithmic conversion on the input voltage amplitude in the same manner as the first log amplifier 308, and outputs the converted voltage amplitude.
　第１包絡線検波部３２１は、第１ログアンプ３２０通過後のデータに対してバンドパスフィルタ、包絡線検波を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。 The first envelope detection unit 321 applies a bandpass filter and an envelope detector to the data after passing through the first log amplifier 320, and generates digital sound line data representing the amplitude or intensity of the echo signal.
　第１座標変換部３２３は、生成した音線データが走査範囲を空間的に正しく表現できるよう、音線データを並べ直す座標変換を施した後、音線データ間の補間処理を施すことによって音線データ間の空隙を埋め、周波数特性が異なる二つのＲＦデータを合成後の新たなＢモード画像データ（新Ｂモード画像データ）を生成する。なお、第１座標変換部３２３は、受信深度が大きいＲＦデータほど高い増幅率で増幅するＳＴＣ（Sensitivity　Time　Control）補正を行ってもよい。さらに、第１座標変換部３２３は、音線データに対してゲイン処理、コントラスト処理等の公知の技術を用いた信号処理を行ってもよい。 The first coordinate conversion unit 323 performs coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly, and then performs interpolation processing between the sound line data to produce sound. The gap between the line data is filled, and new B-mode image data (new B-mode image data) after synthesizing two RF data having different frequency characteristics is generated. The first coordinate conversion unit 323 may perform STC (Sensitivity Time Control) correction that amplifies RF data having a larger reception depth with a higher amplification factor. Further, the first coordinate conversion unit 323 may perform signal processing on the sound line data using known techniques such as gain processing and contrast processing.
　切替スイッチ３２４は、コントロールパネル５Ａから入力される切替信号に基づいて、入力するＲＦデータを、第１Ａ／Ｄコンバータ３０１のＲＦデータ、第２Ａ／Ｄコンバータ３０２のＲＦデータから選択する。切替スイッチ３２４は、選択したＲＦデータを、第２ログアンプ３１２に出力する。 The changeover switch 324 selects the RF data to be input from the RF data of the first A / D converter 301 and the RF data of the second A / D converter 302 based on the changeover signal input from the control panel 5A. The changeover switch 324 outputs the selected RF data to the second log amplifier 312.
　第２包絡線検波部３２５は、第２ログアンプ３１２通過後のデータに対してバンドパスフィルタ、包絡線検波を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。
　本実施の形態３では、第２座標変換部３１５が生成するＢモード画像データを旧Ｂモード画像データとする。 The second envelope detection unit 325 applies a bandpass filter and an envelope detector to the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
In the third embodiment, the B-mode image data generated by the second coordinate conversion unit 315 is used as the old B-mode image data.
　表示画像データ生成部３２６は、第１座標変換部３２３が生成した新Ｂモード画像デーと、第２座標変換部３１５が生成した旧Ｂモード画像データとを用いて、表示装置４に表示させる表示画像データを生成する。表示画像データ生成部３２６は、新Ｂモード画像データと旧Ｂモード画像データとを並べた表示画像データを生成する。 The display image data generation unit 326 displays the new B-mode image data generated by the first coordinate conversion unit 323 and the old B-mode image data generated by the second coordinate conversion unit 315 on the display device 4. Generate image data. The display image data generation unit 326 generates display image data in which the new B mode image data and the old B mode image data are arranged side by side.
　コントロールパネル５Ａには、切替選択つまみ５３が設けられる。切替選択つまみ５３は、回転可能であり、回転位置に応じた切替信号を出力する。コントロールパネル５Ａは、切替選択つまみ５３の回転位置に応じて、第１Ａ／Ｄコンバータ３０１のＲＦデータ、第２Ａ／Ｄコンバータ３０２のＲＦデータ、および、ＲＦデータ選択なし（並列表示なし）のいずれかの切替信号を、切替スイッチ３２４に出力する。 The control panel 5A is provided with a switching selection knob 53. The switching selection knob 53 is rotatable and outputs a switching signal according to the rotation position. The control panel 5A has either RF data of the first A / D converter 301, RF data of the second A / D converter 302, or no RF data selection (no parallel display) according to the rotation position of the switching selection knob 53. The changeover signal of is output to the changeover switch 324.
　図１６は、以上の構成を有する超音波観測装置３Ａが行う処理の概要を示すフローチャートである。超音波プローブに接続された超音波観測装置３Ａは、上述したステップＳ１０１～Ｓ１０４と同様の処理を実行する（ステップＳ３０１～Ｓ３０４）。 FIG. 16 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3A having the above configuration. The ultrasonic observation device 3A connected to the ultrasonic probe executes the same processing as in steps S101 to S104 described above (steps S301 to S304).
　ステップＳ３０５において、第３周波数解析部３１９は、合成スペクトルデータに逆ＦＦＴを施して、ＲＦデータを生成する。第３周波数解析部３１９は、生成したＲＦデータを第１ログアンプ３２０に出力する。 In step S305, the third frequency analysis unit 319 applies an inverse FFT to the composite spectrum data to generate RF data. The third frequency analysis unit 319 outputs the generated RF data to the first log amplifier 320.
　ステップＳ３０６において、第１ログアンプ３２０は、入力される電圧振幅に対し、対数変換を行う。第１ログアンプ３２０は、変換後の電圧振幅を第１包絡線検波部３２１に出力する。 In step S306, the first log amplifier 320 performs logarithmic conversion on the input voltage amplitude. The first log amplifier 320 outputs the converted voltage amplitude to the first envelope detection unit 321.
　ステップＳ３０７において、第１包絡線検波部３２１は、第１ログアンプ３２０通過後のデータに対してバンドパスフィルタ、包絡線検波を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。 In step S307, the first envelope detection unit 321 performs a bandpass filter and an envelope detection on the data after passing through the first log amplifier 320, and generates digital sound line data indicating the amplitude or intensity of the echo signal. do.
　ステップＳ３０８において、第１座標変換部３２３は、生成した音線データが走査範囲を空間的に正しく表現できるよう、音線データを並べ直す座標変換を施して新Ｂモード画像データを生成する。 In step S308, the first coordinate conversion unit 323 generates new B-mode image data by performing coordinate conversion for rearranging the sound line data so that the generated sound line data can express the scanning range spatially correctly.
　ステップＳ３０３と並行して、第２ログアンプ３１２は、切替スイッチ３２４から入力される電圧振幅に対し、対数変換を行う（ステップＳ３０９）。第２ログアンプ３１２は、変換後の電圧振幅を第２包絡線検波部３２５に出力する。 In parallel with step S303, the second log amplifier 312 performs logarithmic conversion on the voltage amplitude input from the changeover switch 324 (step S309). The second log amplifier 312 outputs the converted voltage amplitude to the second envelope detection unit 325.
　ステップＳ３１０において、第２包絡線検波部３２５は、第２ログアンプ３１２通過後のデータに対して包絡線検波等を施し、エコー信号の振幅または強度を表すデジタルの音線データを生成する。 In step S310, the second envelope detection unit 325 performs envelope detection or the like on the data after passing through the second log amplifier 312, and generates digital sound line data representing the amplitude or intensity of the echo signal.
　ステップＳ３１１において、第２座標変換部３１５は、生成した音線データが走査範囲を空間的に正しく表現できるよう、音線データを並べ直す座標変換を施して旧Ｂモード画像データを生成する。 In step S311, the second coordinate conversion unit 315 performs coordinate conversion to rearrange the sound line data so that the generated sound line data can express the scanning range spatially correctly, and generates the old B mode image data.
　ここで、ステップＳ３０３～Ｓ３０８までの新Ｂモード画像データ生成処理と、ステップＳ３０９～Ｓ３１１までの旧Ｂモード画像生成処理とは、同時に行ってもよいし、一方を先に行ってもよい。なお、切替選択つまみ５３によってＲＦデータ選択がない場合は、ステップＳ３０９～Ｓ３１１までの旧Ｂモード画像生成処理は実施されない。 Here, the new B-mode image data generation processing in steps S303 to S308 and the old B-mode image generation processing in steps S309 to S311 may be performed at the same time, or one of them may be performed first. If there is no RF data selected by the switching selection knob 53, the old B-mode image generation processing in steps S309 to S311 is not performed.
　ステップＳ３１２において、表示画像データ生成部３２６は、新Ｂモード画像データと旧Ｂモード画像データとを並べた表示画像データを生成する。 In step S312, the display image data generation unit 326 generates display image data in which the new B mode image data and the old B mode image data are arranged side by side.
　ステップＳ３１３において、表示画像信号生成部３１７は、重畳部３１６が生成した表示画像データや、Ｂモード画像データに対して、表示装置４における画像の表示レンジに応じたデータの間引きや、階調処理などの所定の処理を施して表示画像信号を生成し、表示装置４に出力して表示させる。 In step S313, the display image signal generation unit 317 thins out the display image data generated by the superimposition unit 316 and the B-mode image data according to the display range of the image in the display device 4, and performs gradation processing. A display image signal is generated by performing a predetermined process such as, and is output to the display device 4 for display.
　以上説明した本発明の実施の形態３では、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを用いて、表示するＢモード画像データを生成する。表示画像データ生成部３２６では、十分な周波数帯域において新Ｂモード画像が生成されるため、分解能の高いＢモード画像データを得ることができる。本実施の形態３によれば、Ｂモード画像において、組織間の微妙な相違を鑑別しやすくなる。 In the third embodiment of the present invention described above, the B-mode image data to be displayed is generated by using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal. .. Since the display image data generation unit 326 generates a new B-mode image in a sufficient frequency band, it is possible to obtain B-mode image data with high resolution. According to the third embodiment, it becomes easy to discriminate subtle differences between tissues in the B mode image.
（実施の形態４）
　続いて、本発明の実施の形態４について説明する。図１７は、本発明の実施の形態４に係る超音波観測装置３Ｂを備えた超音波診断システム１Ｂの構成を示すブロック図である。上述した実施の形態１と同じ構成には同じ符号を付し、実施の形態１で説明したものと同じ機能を有する。 (Embodiment 4)
Subsequently, a fourth embodiment of the present invention will be described. FIG. 17 is a block diagram showing a configuration of an ultrasonic diagnostic system 1B including the ultrasonic observation device 3B according to the fourth embodiment of the present invention. The same configurations as those described in the first embodiment are designated by the same reference numerals and have the same functions as those described in the first embodiment.
　本実施の形態４に係る超音波診断システム１Ｂは、上述した実施の形態１に係る超音波診断システム１の構成に対し、超音波観測装置３に代えて超音波観測装置３Ｂを備え、コントロールパネル５に代えてコントロールパネル５Ｂを備える。実施の形態１の超音波診断装置３と異なる構成として、超音波観測装置３Ｂは、第４周波数解析部３２７、および重畳割合設定つまみ５４を備える。 The ultrasonic diagnostic system 1B according to the fourth embodiment includes an ultrasonic observation device 3B instead of the ultrasonic observation device 3 for the configuration of the ultrasonic diagnostic system 1 according to the first embodiment described above, and is a control panel. A control panel 5B is provided instead of 5. As a configuration different from the ultrasonic diagnostic apparatus 3 of the first embodiment, the ultrasonic observation apparatus 3B includes a fourth frequency analysis unit 327 and a superposition ratio setting knob 54.
　第４周波数解析部３２７は、合成部３０７からの合成スペクトルデータに対し、逆ＦＦＴを施す。第４周波数解析部３２７の処理によって生成されるデータは、第１Ａ／Ｄコンバータ３０１および第２Ａ／Ｄコンバータ３０２から出力されるＲＦデータの合成データに相当する。第４周波数解析部３２７は、生成したＲＦデータを、第２ログアンプ３１２に出力する。 The fourth frequency analysis unit 327 performs an inverse FFT on the composite spectrum data from the synthesis unit 307. The data generated by the processing of the fourth frequency analysis unit 327 corresponds to the composite data of the RF data output from the first A / D converter 301 and the second A / D converter 302. The fourth frequency analysis unit 327 outputs the generated RF data to the second log amplifier 312.
　コントロールパネル５Ｂには、重畳割合設定つまみ５４が設けられる。重畳割合設定つまみ５４は、回転可能であり、回転位置に応じた設定信号を出力する。 The control panel 5B is provided with a superposition ratio setting knob 54. The superposition ratio setting knob 54 is rotatable and outputs a setting signal according to the rotation position.
　重畳割合設定つまみ５４は、重畳部３１６における特徴量画像データの重畳割合を入力する。例えば、重畳割合設定つまみ５４の回転位置によって、第１座標変換部３１０からの特徴量画像データ（Ａ）と、第２座標変換部３１５からのＢモード画像データ（Ｂ）との比（Ａ：Ｂ）が設定されている。Ａ：Ｂは、重畳し得る割合に応じて１００：０、０：１００、５０：５０、７０：３０等の比が設定される。 The superimposition ratio setting knob 54 inputs the superimposition ratio of the feature amount image data in the superimposition unit 316. For example, the ratio of the feature amount image data (A) from the first coordinate conversion unit 310 to the B mode image data (B) from the second coordinate conversion unit 315 (A:) depending on the rotation position of the superposition ratio setting knob 54. B) is set. For A: B, ratios such as 100: 0, 0: 100, 50:50, and 70:30 are set according to the ratio that can be superimposed.
　図１８は、以上の構成を有する超音波観測装置３Ｂが行う処理の概要を示すフローチャートである。超音波観測装置３Ｂは、上述したステップＳ１０１～Ｓ１０７と同様の処理を実行する（ステップＳ４０１～Ｓ４０７）。 FIG. 18 is a flowchart showing an outline of the processing performed by the ultrasonic observation device 3B having the above configuration. The ultrasonic observation device 3B executes the same processing as in steps S101 to S107 described above (steps S401 to S407).
　実施の形態４では、実施の形態１とは異なり、ステップＳ４０４で周波数スペクトルを合成した後に、ステップＳ４０５の対数変換処理と並行して、第４周波数解析部３２７の処理を行う。第４周波数解析部３２７は、合成スペクトルデータに逆ＦＦＴを施して、ＲＦデータを生成する（ステップＳ４０８）。第４周波数解析部３２７は、生成したＲＦデータを第２ログアンプ３１２に出力する。 In the fourth embodiment, unlike the first embodiment, after the frequency spectrum is synthesized in step S404, the process of the fourth frequency analysis unit 327 is performed in parallel with the logarithmic conversion process of step S405. The fourth frequency analysis unit 327 applies an inverse FFT to the synthesized spectrum data to generate RF data (step S408). The fourth frequency analysis unit 327 outputs the generated RF data to the second log amplifier 312.
　ステップＳ４０９において、第２ログアンプ３１２は、第４周波数解析部３２７から入力される電圧振幅に対し、対数変換を行う（ステップＳ３０９）。第２ログアンプ３１２は、変換後の電圧振幅を第２包絡線検波部３２５に出力する。 In step S409, the second log amplifier 312 performs logarithmic conversion on the voltage amplitude input from the fourth frequency analysis unit 327 (step S309). The second log amplifier 312 outputs the converted voltage amplitude to the second envelope detection unit 325.
　超音波観測装置３Ｂは、上述したステップＳ１１０～Ｓ１１３と同様の処理を実行する（ステップＳ４１０～Ｓ４１３）。ステップＳ４１２において、重畳部３１６は、重畳割合設定つまみ５４から入力される重畳割合データに基づいて、Ｂモード画像データ上に特徴量画像データを重畳して、表示装置４に表示させる表示画像データを生成する。 The ultrasonic observation device 3B executes the same processing as in steps S110 to S113 described above (steps S410 to S413). In step S412, the superimposition unit 316 superimposes the feature amount image data on the B mode image data based on the superimposition ratio data input from the superimposition ratio setting knob 54, and displays the display image data displayed on the display device 4. Generate.
　以上説明した本発明の実施の形態４では、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを用いて、特徴量を算出する。特徴量算出部３０９では、十分な周波数帯域において回帰直線を求めることができる。これは、高周波のエコー信号のみ、または低周波のエコー信号のみを用いて回帰直線を求める場合と比して、特徴量を精度よく算出することができる。本実施の形態４によれば、高精度に特徴量を算出することによって、組織間の微妙な相違を鑑別しやすくなる。 In the fourth embodiment of the present invention described above, the feature amount is calculated using the high-frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low-frequency echo signal. The feature amount calculation unit 309 can obtain a regression line in a sufficient frequency band. This makes it possible to calculate the feature amount more accurately than in the case of obtaining the regression line using only the high-frequency echo signal or only the low-frequency echo signal. According to the fourth embodiment, by calculating the feature amount with high accuracy, it becomes easy to discriminate subtle differences between tissues.
　また、実施の形態４では、互いに異なる周波数特性を有する超音波振動子から受信した高周波のエコー信号と、低周波のエコー信号とを合成したＲＦデータを用いて、表示するＢモード画像データを生成する。第２座標変換部３１５では、十分な周波数帯域において新Ｂモード画像が生成されるため、分解能の高いＢモード画像データを得ることができる。本実施の形態４によれば、Ｂモード画像において、組織間の微妙な相違を鑑別しやすくなる。 Further, in the fourth embodiment, the B mode image data to be displayed is generated by using the RF data obtained by synthesizing the high frequency echo signal received from the ultrasonic transducers having different frequency characteristics and the low frequency echo signal. do. Since the new B-mode image is generated in a sufficient frequency band in the second coordinate conversion unit 315, B-mode image data having high resolution can be obtained. According to the fourth embodiment, it becomes easy to discriminate subtle differences between tissues in the B mode image.
　ここまで、本発明を実施するための形態を説明してきたが、本発明は、上述した実施の形態によってのみ限定されるべきものではない。例えば、超音波観測装置において、各機能を有する回路同士をバスで接続することによって構成してもよいし、一部の機能が他の機能の回路構造に内蔵される構成としてもよい。 Although the embodiments for carrying out the present invention have been described so far, the present invention should not be limited only to the above-described embodiments. For example, in an ultrasonic observation device, circuits having each function may be connected by a bus, or some functions may be incorporated in a circuit structure of another function.
　また、本実施の形態１～４では、超音波プローブとして、光学レンズおよび撮像素子を有しない管腔内超音波プローブや、撮像光学系を有する超音波内視鏡を用いて説明したが、これらに限らず、光学系のない細径の超音波ミニチュアプローブを適用してもよい。超音波ミニチュアプローブは、通常、胆道、胆管、膵管、気管、気管支、尿道、尿管へ挿入され、その周囲臓器（膵臓、肺、前立腺、膀胱、リンパ節等）を観察する際に用いられる。 Further, in the first to fourth embodiments, as the ultrasonic probe, an intraluminal ultrasonic probe having no optical lens and an imaging element and an ultrasonic endoscope having an imaging optical system have been described. However, a small-diameter ultrasonic miniature probe without an optical system may be applied. Ultrasonic miniature probes are usually inserted into the biliary tract, bile ducts, pancreatic ducts, trachea, bronchi, urethra, and ureters and used to observe surrounding organs (pancreas, lungs, prostate, bladder, lymph nodes, etc.).
　また、超音波プローブとして、被検体の体表から超音波を照射する体外式超音波プローブを適用してもよい。体外式超音波プローブは、通常、腹部臓器（肝臓、胆嚢、膀胱）、乳房（特に乳腺）、甲状腺を観察する際に体表に直接接触させて用いられる。 Further, as the ultrasonic probe, an extracorporeal ultrasonic probe that irradiates ultrasonic waves from the body surface of the subject may be applied. Extracorporeal ultrasound probes are typically used in direct contact with the body surface when observing abdominal organs (liver, gallbladder, bladder), breasts (particularly mammary glands), and thyroid glands.
　また、超音波振動子は、リニア型の振動子でもラジアル型の振動子でもコンベックス振動子でも構わない。超音波振動子がリニア振動子である場合、その走査領域は矩形（長方形、正方形）をなし、超音波振動子がラジアル振動子やコンベックス振動子である場合、その走査領域は扇形や円環状をなす。また、超音波振動子は、圧電素子が二次元的に配置されるものであってもよい。また、超音波内視鏡は、超音波振動子をメカ的に走査させるものであってもよいし、超音波振動子として複数の素子をアレイ状に設け、送受信にかかわる素子を電子的に切り替えたり、各素子の送受信に遅延をかけたりすることで、電子的に走査させるものであってもよい。 Further, the ultrasonic vibrator may be a linear type vibrator, a radial type vibrator, or a convex vibrator. When the ultrasonic oscillator is a linear oscillator, its scanning area is rectangular (rectangular, square), and when the ultrasonic oscillator is a radial oscillator or convex oscillator, its scanning area is fan-shaped or annular. Rectangle. Further, the ultrasonic vibrator may have a piezoelectric element arranged two-dimensionally. Further, the ultrasonic endoscope may be one that mechanically scans the ultrasonic vibrator, or a plurality of elements are provided in an array as the ultrasonic vibrator, and the elements involved in transmission / reception are electronically switched. Alternatively, it may be electronically scanned by delaying the transmission and reception of each element.
　また、超音波観測装置は、据置型に限らず、ポータブル、ウェアラブルの装置としてもよい。ポータブル、ウェアラブルの超音波観測装置とした場合、超音波観測装置には小型化することが要求される。また、超音波プローブ自体も細径化が求められる場合、超音波振動子を配設する空間的な余裕がなくなり、周波数帯域が狭くなりがちである。この構成に本実施の形態を適用することによって、高精度な特徴量を算出し、深度によらず精度の高い特徴量画像を得ることができる。 Further, the ultrasonic observation device is not limited to the stationary type, and may be a portable or wearable device. In the case of a portable and wearable ultrasonic observation device, the ultrasonic observation device is required to be miniaturized. Further, when the diameter of the ultrasonic probe itself is required to be reduced, there is no space for arranging the ultrasonic vibrator, and the frequency band tends to be narrowed. By applying the present embodiment to this configuration, it is possible to calculate a highly accurate feature amount and obtain a highly accurate feature amount image regardless of the depth.
　本発明は、請求の範囲に記載した技術的思想を逸脱しない範囲内において、様々な実施の形態を含みうるものである。 The present invention may include various embodiments within a range that does not deviate from the technical idea described in the claims.
　以上説明した通り、本発明にかかる超音波画像生成装置、超音波画像生成装置の作動方法、超音波画像生成装置の作動プログラムおよび超音波画像生成回路は、超音波信号に基づく画像であって、組織の性状を高精度に表現する画像を得るのに有用である。 As described above, the ultrasonic image generator, the operation method of the ultrasonic image generator, the operation program of the ultrasonic image generator, and the ultrasonic image generation circuit according to the present invention are images based on the ultrasonic signal. It is useful for obtaining an image that expresses the properties of the tissue with high accuracy.
　１、１Ａ、１Ｂ　超音波診断システム
　２　超音波内視鏡
　３、３Ａ、３Ｂ　超音波観測装置
　４　表示装置
　５、５Ａ、５Ｂ　コントロールパネル
　２１、２１Ａ、２１Ｂ　挿入部
　２２　操作部
　２１１　第１超音波振動子
　２１２　第２超音波振動子
　２１３　バッキング材
　２１４　フレキシブルシャフト
　２１５、２１７　超音波振動子
　２１６　撮像光学系
　３００　接続部
　３０１　第１Ａ／Ｄコンバータ
　３０２　第２Ａ／Ｄコンバータ
　３０３　第１周波数解析部
　３０４　第２周波数解析部
　３０５、３０６、３１４、３２２　バッファ
　３０７　合成部
　３０８、３２０　第１ログアンプ
　３０９　特徴量算出部
　３１０、３２３　第１座標変換部
　３１１　混合部
　３１２　第２ログアンプ
　３１３　包絡線検波部
　３１５　第２座標変換部
　３１６　重畳部
　３１７　表示画像信号生成部
　３１８　記憶部
　３１９　第３周波数解析部
　３２１　第１包絡線検波部
　３２４　切替スイッチ
　３２５　第２包絡線検波部
　３２６　表示画像データ生成部
　３２７　第４周波数解析部 1, 1A, 1B Ultrasonic diagnostic system 2 Ultrasonic endoscope 3, 3A, 3B Ultrasonic observation device 4 Display device 5, 5A, 5B Control panel 21, 21A, 21B Insertion part 22 Operation part 211 First ultrasonic vibration Child 212 2nd ultrasonic transducer 213 Backing material 214 Flexible shaft 215, 217 Ultrasonic transducer 216 Imaging optical system 300 Connection part 301 1st A / D converter 302 2nd A / D converter 303 1st frequency analysis part 304 2nd frequency Analysis unit 305, 306, 314, 322 Buffer 307 Synthesis unit 308, 320 1st log amplifier 309 Feature calculation unit 310, 323 1st coordinate conversion unit 311 Mixing unit 312 2nd log amplifier 313 Envelopment line detection unit 315 2nd coordinates Conversion unit 316 Superimposition unit 317 Display image signal generation unit 318 Storage unit 319 Third frequency analysis unit 321 First wrapping line detection unit 324 Changeover switch 325 Second wrapping line detection unit 326 Display image data generation unit 327 Fourth frequency analysis unit

Claims (14)

  1. 　超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する、超音波画像生成装置において、
    　前記第１の超音波信号について第１の周波数スペクトルデータを生成する第１周波数解析部と、
    　前記第２の超音波信号について第２の周波数スペクトルデータを生成する第２周波数解析部と、
    　前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成する合成部と、
    　前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する表示画像データ生成部と、
    　を備える超音波画像生成装置。     In an ultrasonic image generator that receives a first ultrasonic signal and a second ultrasonic signal having different frequency characteristics from the first ultrasonic signal from the ultrasonic echo and generates an ultrasonic image.
    A first frequency analysis unit that generates first frequency spectrum data for the first ultrasonic signal,
    A second frequency analysis unit that generates a second frequency spectrum data for the second ultrasonic signal, and a second frequency analysis unit.
    A compositing unit that synthesizes the first frequency spectrum data and the second frequency spectrum data to generate synthetic spectrum data, and a compositing unit.
    A display image data generation unit that generates display image data to be displayed on a display device based on the composite spectrum data, and a display image data generation unit.
    An ultrasonic image generator equipped with.
  2. 　前記合成スペクトルデータに基づいて特徴量を算出する特徴量算出部、
    　前記特徴量に応じて色情報を付与した特徴量画像データを生成する特徴量画像データ生成部と、
    　をさらに備える請求項１に記載の超音波画像生成装置。     A feature amount calculation unit that calculates a feature amount based on the composite spectrum data,
    A feature amount image data generation unit that generates feature amount image data to which color information is added according to the feature amount, and a feature amount image data generation unit.
    The ultrasonic image generator according to claim 1.
  3. 　前記特徴量算出部は、
    　前記合成スペクトルデータから算出した回帰直線に基づいて前記特徴量を算出する、
    　請求項２に記載の超音波画像生成装置。     The feature amount calculation unit
    The feature amount is calculated based on the regression line calculated from the synthesized spectrum data.
    The ultrasonic image generator according to claim 2.
  4. 　前記第１の超音波信号および前記第２の超音波信号のうちの少なくとも一方を用いてＢモード画像データを生成するＢモード画像データ生成部、
    　をさらに備える請求項１に記載の超音波画像生成装置。     A B-mode image data generation unit that generates B-mode image data using at least one of the first ultrasonic signal and the second ultrasonic signal.
    The ultrasonic image generator according to claim 1.
  5. 　前記合成部は、線形表現の前記第１の周波数スペクトルデータと、線形表現の前記第２の周波数スペクトルデータとを加算して前記合成スペクトルデータを生成する、
    　請求項１に記載の超音波画像生成装置。     The synthesis unit generates the composite spectrum data by adding the first frequency spectrum data in the linear representation and the second frequency spectrum data in the linear representation.
    The ultrasonic image generator according to claim 1.
  6. 　前記第１の超音波信号および前記第２の超音波信号のうちの少なくとも一方を用いてＢモード画像データを生成するＢモード画像データ生成部、
    　をさらに備え、
    　前記画像データ生成部は、前記特徴量画像データの座標と、前記Ｂモード画像データの座標とを対応させて、前記特徴量に応じた色情報を前記Ｂモード画像データ上に配置する、
    　請求項２に記載の超音波画像生成装置。     A B-mode image data generation unit that generates B-mode image data using at least one of the first ultrasonic signal and the second ultrasonic signal.
    With more
    The image data generation unit makes the coordinates of the feature amount image data correspond to the coordinates of the B mode image data, and arranges color information corresponding to the feature amount on the B mode image data.
    The ultrasonic image generator according to claim 2.
  7. 　前記Ｂモード画像データ生成部は、前記合成スペクトルデータを用いて前記Ｂモード画像データを生成する、
    　請求項４に記載の超音波画像生成装置。     The B-mode image data generation unit generates the B-mode image data using the composite spectrum data.
    The ultrasonic image generator according to claim 4.
  8. 　前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとの取得位置を補正する位置補正部、
    　をさらに備える請求項１に記載の超音波画像生成装置。     A position correction unit that corrects the acquisition position of the first frequency spectrum data and the second frequency spectrum data.
    The ultrasonic image generator according to claim 1.
  9. 　前記Ｂモード画像データ生成部は、前記第１の周波数スペクトルデータと、前記第２の周波数スペクトルデータとを、設定される混合割合に応じて混合して前記Ｂモード画像データを生成する、
    　請求項６に記載の超音波画像生成装置。     The B-mode image data generation unit generates the B-mode image data by mixing the first frequency spectrum data and the second frequency spectrum data according to a set mixing ratio.
    The ultrasonic image generator according to claim 6.
  10. 　前記表示画像データ生成部は、設定される前記特徴量画像データの重畳割合に応じて、前記特徴量画像データを前記Ｂモード画像データに重畳する、
    　請求項６に記載の超音波画像生成装置。     The display image data generation unit superimposes the feature amount image data on the B mode image data according to a set superposition ratio of the feature amount image data.
    The ultrasonic image generator according to claim 6.
  11. 　前記合成スペクトルデータを対数変換するログアンプ、
    　をさらに備える請求項１に記載の超音波画像生成装置。     A log amplifier that logarithmically transforms the synthesized spectrum data,
    The ultrasonic image generator according to claim 1.
  12. 　超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する超音波画像生成装置の作動方法であって、
    　第１周波数解析部が、前記第１の超音波信号について第１の周波数スペクトルデータを生成し、
    　第２周波数解析部が、前記第２の超音波信号について第２の周波数スペクトルデータを生成し、
    　合成部が、前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、
    　画像データ生成部が、前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する
    　超音波画像生成装置の作動方法。     A method of operating an ultrasonic image generator that receives a first ultrasonic signal and a second ultrasonic signal having different frequency characteristics from the first ultrasonic signal from the ultrasonic echo and generates an ultrasonic image. And
    The first frequency analysis unit generates the first frequency spectrum data for the first ultrasonic signal, and the first frequency analysis unit generates the first frequency spectrum data.
    The second frequency analysis unit generates the second frequency spectrum data for the second ultrasonic signal, and the second frequency analysis unit generates the second frequency spectrum data.
    The synthesizing unit synthesizes the first frequency spectrum data and the second frequency spectrum data to generate the synthesized spectrum data.
    A method of operating an ultrasonic image generation device in which an image data generation unit generates display image data to be displayed on a display device based on the composite spectrum data.
  13. 　超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信して超音波画像を生成する超音波画像生成装置に実行させる作動プログラムであって、
    　前記第１の超音波信号について第１の周波数スペクトルデータを生成し、
    　前記第２の超音波信号について第２の周波数スペクトルデータを生成し、
    　前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、
    　前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する、
    　超音波画像生成装置の作動プログラム。     From the ultrasonic echo, a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal are received and executed by an ultrasonic image generator that generates an ultrasonic image. It ’s an operation program,
    The first frequency spectrum data is generated for the first ultrasonic signal, and the first frequency spectrum data is generated.
    A second frequency spectrum data is generated for the second ultrasonic signal, and the second frequency spectrum data is generated.
    The first frequency spectrum data and the second frequency spectrum data are combined to generate synthetic spectrum data.
    Based on the synthesized spectrum data, display image data to be displayed on the display device is generated.
    Operation program of the ultrasonic image generator.
  14. 　超音波エコーから、第１の超音波信号、および該第１の超音波信号とは周波数特性が異なる第２の超音波信号を受信し、
    　前記第１の超音波信号について第１の周波数スペクトルデータを生成し、
    　前記第２の超音波信号について第２の周波数スペクトルデータを生成し、
    　前記第１の周波数スペクトルデータと前記第２の周波数スペクトルデータとを合成して合成スペクトルデータを生成し、
    　前記合成スペクトルデータに基づいて、表示装置に表示させる表示画像データを生成する、
    　処理を実行する超音波画像生成回路。     From the ultrasonic echo, a first ultrasonic signal and a second ultrasonic signal having a frequency characteristic different from that of the first ultrasonic signal are received, and the ultrasonic signal is received.
    The first frequency spectrum data is generated for the first ultrasonic signal, and the first frequency spectrum data is generated.
    A second frequency spectrum data is generated for the second ultrasonic signal, and the second frequency spectrum data is generated.
    The first frequency spectrum data and the second frequency spectrum data are combined to generate synthetic spectrum data.
    Based on the synthesized spectrum data, display image data to be displayed on the display device is generated.
    An ultrasonic image generation circuit that executes processing.
PCT/JP2020/009262 2020-03-04 2020-03-04 Ultrasound image generation device, ultrasound image generation device operating method, ultrasound image generation device operating program, and ultrasound image generation circuit WO2021176618A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003284719A (en) * 2002-03-27 2003-10-07 Aloka Co Ltd Ultrasonic diagnostic device
JP2014184073A (en) * 2013-03-25 2014-10-02 Canon Inc Subject information acquisition device
JP2018191779A (en) * 2017-05-15 2018-12-06 オリンパス株式会社 Ultrasonic observation device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003284719A (en) * 2002-03-27 2003-10-07 Aloka Co Ltd Ultrasonic diagnostic device
JP2014184073A (en) * 2013-03-25 2014-10-02 Canon Inc Subject information acquisition device
JP2018191779A (en) * 2017-05-15 2018-12-06 オリンパス株式会社 Ultrasonic observation device

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