JP2003334192A - Ultrasonic diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and accurately estimate the positions of a plurality of images obtained by manually scanning an ultrasonic probe in the direction of slicing. <P>SOLUTION: This ultrasonic diagnostic equipment has the ultrasonic probe 1, an ultrasonic transmission means 2 and an ultrasonic reception means 3, a first image forming means and a second image forming means which form images out of received signals obtained by the reception means, a first storage means 25 and a second storage means 22 which store the images obtained by these image forming means, an image position estimating means 23 which determines the information on the relative positions of two images obtained from the second storage means, and a means which relocates the first image on the basis of the positional information and generates three-dimensional image data. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus having a function of estimating a distance between images obtained in a slice direction.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus radiates ultrasonic waves generated by an ultrasonic transducer incorporated in an ultrasonic probe into a subject, and ultrasonically oscillates a reflection signal generated by a difference in acoustic impedance of the subject tissue. It is received by the child and displayed on the monitor.

This diagnostic method is widely used for functional examination of the heart and morphological diagnosis of various organs because a real-time two-dimensional image can be easily observed by a simple operation of bringing an ultrasonic probe into contact with the body surface. Especially, since there is almost no irradiation damage given to the subject, it is an indispensable imaging method for the developmental diagnosis of the fetus.

In addition, since it has high safety and operability as described above, and the scale of the apparatus is smaller than other image diagnostic equipment such as X-ray, CT, and MRI, it is suitable for bedside examination. Application is also being attempted.

Recently, even in the field of ultrasonic diagnosis, X
Similar to line CT and MRI, clinical needs for three-dimensional images are increasing. The three-dimensional image information has information in the depth direction, which is not present in conventional two-dimensional images. Therefore, by applying appropriate image processing to this information, the shape of tissue and the running of blood vessels can be displayed three-dimensionally. It becomes possible to do.

[0006] In collecting three-dimensional image information, it is necessary to perform ultrasonic scanning on a subject to acquire three-dimensional image data, but various attempts have been made so far for the collecting method. There is.

As a first method, a method has been proposed in which echo signals from three-dimensionally distributed reflectors are captured by using a so-called two-dimensional array probe in which ultrasonic transducers are two-dimensionally arranged. This method compared to the method described below,
Ultrasonic scanning by electronic control is all possible, so it is excellent in real time and operability, but the two-dimensional array probe is still in the research stage, and even if it reaches the stage of practical application, it may be expensive. Is high.

As a second method, the ultrasonic transducer is arranged in a direction (hereinafter referred to as a slice direction) perpendicular to the image plane of a two-dimensional image obtained by a conventional one-dimensional array probe having a one-dimensional array. There is a method of moving and reconstructing a three-dimensional image from a plurality of two-dimensional images continuously obtained at this time.

This second method is further classified into two methods. That is, a method of collecting a plurality of two-dimensional images while moving a one-dimensional array probe equipped with a position sensor such as a magnetic sensor at a minute interval in a slicing method and an operator (that is, a doctor) without using the position sensor. There is a method of collecting a plurality of two-dimensional images while moving the one-dimensional array probe along the body surface of the subject at a predetermined movement speed and a predetermined movement angle according to the intuition of an inspection engineer. In the former method, while moving the ultrasonic probe in an arbitrary direction, the two-dimensional image data and the position information of the one-dimensional array probe obtained from the position sensor at that time are read into the device and the two-dimensional image is read based on this position information. The image data is arranged three-dimensionally to reconstruct a three-dimensional image.

This second method can be realized by a relatively simple technique as compared with the first method, and has already reached the stage of practical application, but the former method is a transmitter at the bedside. Is required, and the position sensor must be mounted, which impairs the operability of the ultrasonic probe. In particular, when the operator's arm or the like is interposed between the position detecting transmitter and the position sensor, there is a problem that position detection becomes difficult. On the other hand, the latter method has a drawback that it cannot be applied to formal measurement because the position information is inaccurate.

As a conventional method for solving such a problem, the relative distance between the images is detected by the correlation processing between the images in the slice direction without using the position sensor as described above, and the accurate 3 A method for obtaining a three-dimensional image has been proposed. (Iwaki Akiyama, Toshiyuki Toyoda, Akihisa Oya, “Examination of 3D image composition from ultrasonic tomographic images --- Speckle pattern tracking and correlation function”, Japan Society of Ultrasonic Medicine Basic Technology Research Group BT-2000-20 , pp.33-38 (2000)).

This method focuses on the characteristics of a speckle pattern (graininess pattern generated by random interference of ultrasonic waves) that appears in an ultrasonic image. That is, when the position at which the ultrasonic image is collected moves in the slice direction, the speckle pattern on the image changes with distance, so the degree of change is obtained as a cross-correlation coefficient, and the moving distance is calculated. is there.

In this method, the relationship between the moving distance and the correlation coefficient needs to be known in advance from the ultrasonic transmission / reception conditions to be used, but there is a possibility that a minute moving distance can be accurately measured.

[0014]

However, the method of calculating the moving distance from the cross-correlation coefficient between images in the slice direction has the following problems. That is, as described in the above cited document, the change in the speckle pattern seen in the ultrasonic diagnostic image is extremely sensitive to the movement in the slice direction of the image, while the movement distance, that is, the inter-image distance. However, there is a problem that the detection sensitivity decreases as the value increases, and this phenomenon is remarkable when a high ultrasonic frequency is used. On the other hand, in the acquisition of three-dimensional image data, it is clinically required to scan a predetermined region in the slice direction within a predetermined time, and therefore there is a limit to setting a small image interval in the slice direction. That is, when the correlation processing between the images in the slice direction is performed by the imaging method of the conventional apparatus, the correlation becomes too small and it is difficult to measure the distance accurately.

The present invention has been made in order to solve such a conventional problem, and an object thereof is an ultrasonic wave capable of estimating a distance even between images having a relatively large distance in the slice direction. To provide a diagnostic device.

[0016]

In order to solve the above-mentioned problems, in the ultrasonic diagnostic apparatus of the present invention, an ultrasonic probe having an ultrasonic transducer for transmitting and receiving ultrasonic waves, and the ultrasonic probe Based on the output ultrasonic echo signal,
A signal processing means for generating first data and second data, a distance calculation means for obtaining a distance based on the similarity between the first and second data, and an output of the ultrasonic probe and the distance. And a means for generating three-dimensional image data. Therefore, according to the present invention, it is possible to obtain a plurality of ultrasonic images having relative position information without mounting a position sensor on the ultrasonic probe, so that three-dimensional image data can be collected easily and accurately. It becomes possible.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) The feature of the present embodiment is that the images used when estimating the relative distance between the ultrasonic images in the slice direction are used for the purpose of the original ultrasonic diagnosis as in the prior art. In place of the obtained image (hereinafter referred to as diagnostic image or diagnostic B-mode image), a measurement-specific image (hereinafter referred to as measurement B-mode image) generated from the low-frequency component of the received signal for the purpose of measuring the distance between images is used. is there.

A first embodiment of the present invention will be described with reference to FIGS. 1 and 2 are block diagrams showing a schematic configuration of the ultrasonic diagnostic apparatus according to the first embodiment.

In this ultrasonic diagnostic apparatus, an ultrasonic probe 1 for contacting the surface of a subject to transmit and receive ultrasonic waves, and an ultrasonic transmitter 2 for generating a drive signal for generating ultrasonic waves.
An ultrasonic receiving unit 3 for receiving an ultrasonic reflection signal from the inside of the subject; a band limiting unit 40 for limiting the frequency band of the received signal; and a display unit for displaying the received signal as a B-mode image on a monitor. A B-mode processing unit 4 that performs signal processing and a Doppler mode processing unit 6 that performs signal processing for displaying a color Doppler image are provided.

Further, the ultrasonic diagnostic apparatus stores a three-dimensional image generation unit 5 for generating three-dimensional image data from a plurality of ultrasonic images collected in the slice direction and various kinds of obtained data as image data, A display image generation unit 7 for converting into a format, a system control unit 8 for integrally controlling each of these units, a display unit 10 and an input unit 9 are provided.

The ultrasonic probe 1 sends and receives ultrasonic waves by bringing its front surface into contact with the surface of the subject.
A plurality of micro-ultrasonic transducers arranged one-dimensionally are provided at the tip portion thereof. This ultrasonic transducer is an electroacoustic transducer, and has a function of converting an electric pulse into an ultrasonic pulse during transmission and converting an ultrasonic signal into an electric signal during reception. The ultrasonic frequency that greatly affects the resolution and sensitivity of the ultrasonic image is almost determined by the thickness of this ultrasonic transducer. This ultrasonic probe 1 is small,
It is lightweight and is connected to an ultrasonic wave transmitting unit 2 and an ultrasonic wave receiving unit 3 described later by a cable. The ultrasonic probe 1 is arbitrarily selected from among sector scan compatible, linear scan compatible, convex scan compatible, etc. according to the diagnosis region. Below, the case where the ultrasonic probe 1 for sector scanning is used will be described. .

The ultrasonic wave transmitting section 2 includes a rate signal generator 11
A transmission delay circuit 12 and a pulser 13. The rate signal generator 11 emits a rate pulse that determines the repetition period of the ultrasonic pulse emitted inside the subject. The transmission delay circuit 12 is a delay circuit for determining the convergence distance and the deflection angle of the ultrasonic beam during transmission,
The timing for driving the plurality of ultrasonic transducers is determined. The pulsar 13 is a drive circuit that generates a high-voltage pulse for driving the ultrasonic transducer.

The rate pulse generator 11 supplies the transmission delay circuit 12 with a rate pulse that determines the repetition period of the ultrasonic pulse radiated into the subject. The transmission delay circuit 12 is composed of a plurality of independent delay circuits, which is almost the same number as the ultrasonic transducers used for transmission, and converges the ultrasonic waves to a predetermined depth in order to obtain a narrow beam width in transmission. And the delay time for transmitting ultrasonic waves in a predetermined direction are given to the rate pulse and supplied to the pulser 13.

Similar to the transmission delay circuit 12, the pulsar 13 has a plurality of independent drive circuits, which is almost the same number as the ultrasonic transducers used for transmission, and the ultrasonic wave built in the ultrasonic probe 1 is used. A drive pulse for driving the oscillator and emitting ultrasonic waves is formed.

The ultrasonic wave receiving unit 3 includes a preamplifier 14, a reception delay circuit 15, and an adder 16. The preamplifier 14 amplifies a minute signal converted into an electric signal by the ultrasonic transducer and secures a sufficient S / N. The reception delay circuit 15 sequentially switches the delay time for convergence for converging the ultrasonic waves from a predetermined depth in order to obtain a narrow reception beam width and the reception direction of the ultrasonic beam to a predetermined direction to sequentially detect the inside of the subject. After the deflection delay time for scanning is sent to the output signal of the preamplifier 14, it is sent to the adder 16, and the adder 16 adds a plurality of received signals, and the adder 16 adds a plurality of received signals from the ultrasonic transducers. The received signals of are combined into one.

The band limiting section 40 is provided with a filter 17 for extracting only low frequency components from the received signal and a switch 18. This filter 17 detects the ultrasonic signal when measuring the distance between ultrasonic images in the slice direction. Emphasize low frequency components.

The B-mode processing unit 4 comprises a logarithmic converter 19, an envelope detector 20 and an A / D converter 21. The logarithmic converter 19 of the B-mode processing unit 4 logarithmically converts the amplitude of the input signal and relatively emphasizes the weak signal. Generally, a received signal from within the subject has an amplitude having a wide dynamic range of 80 dB or more, and an amplitude that emphasizes a weak signal in order to display this on a normal television monitor having a dynamic range of about 30 dB. Compression is done. The envelope detector 20 performs envelope detection on the logarithmically converted received signal, removes the ultrasonic frequency component, and detects only its amplitude. The A / D converter 21 is the envelope detector 20.
A / D conversion is performed on the output signal of 1 to form a B mode signal.

The Doppler mode processing unit 6 includes the reference signal generator 2
7, a π / 2 phase shifter 28, a mixer 29, an LPF (low-pass filter) 30, an A / D converter 31, a Doppler signal storage circuit 50, an FFT analyzer 32, and a calculator 33.
It has and. The Doppler mode processing unit 6 mainly performs quadrature detection and FFT analysis.

That is, the input signal of the Doppler mode processing unit 6 is input to the first input terminals of the mixers 29-1 and 29-2. On the other hand, the output of the reference signal generator 27 having a frequency substantially equal to the frequency of this input signal is the mixer 29-1.
9 directly via the π / 2 phase shifter 28 to the second input terminal of
The 0-degree phase-shifted output is sent to the second input terminal of the mixer 29-2. The outputs of the mixers 29-1 and 29-2 are sent to the low pass filters 30-1 and 30-2, and the sum component of the frequency of the input signal of the Doppler mode processing unit 6 and the frequency of the reference signal generator 27 is removed. , Only the difference component is extracted.

The A / D converter 31 includes LPFs 30-1 and 30.
-2 output, that is, the quadrature detection output is converted into a digital signal, the FFT analyzer 32 temporarily stores the digitized quadrature component in the Doppler signal storage circuit 50, and then the FFT analyzer 32 performs FFT analysis. On the other hand, the calculator 33
Calculates the center value or variance value of the spectrum obtained by the FFT analyzer 32.

The three-dimensional image generator 5 includes an image memory 22 for distance measurement, an image position detector 23, and image control circuits 24 and 3.
A three-dimensional image memory 25 and a buffer memory 26 are provided.

Further, the image position detecting section 23, as shown in FIG. 2, has a frame memory A36-1 and a frame memory B.
36-2, correlation processor 37, and lookup table 38
Is equipped with.

The three-dimensional image memory 25 is the ultrasonic probe 1.
Save a plurality of diagnostic images obtained by moving in the slice direction. On the other hand, the distance measurement image memory 22 stores a plurality of measurement B-mode images separately collected for estimating the relative distance between the plurality of diagnosis images. The B-mode image for measurement is collected at the same position as the image for diagnosis under different transmission / reception conditions.

The image control circuit 24 reads out two predetermined adjacent images from the distance measuring image memory 22 and temporarily stores them in the frame memory A36-1 and the frame memory B36-2 of the image position detecting section 23. The cross-correlator 47 of the image position detector 23 calculates a cross-correlation coefficient from the image data stored in the frame memory A36-1 and the frame memory B36-2, respectively. On the other hand, the lookup table 38 of the image position detector 23 stores a table in which the inter-image distance is output when the cross-correlation coefficient is input. The correspondence between the cross-correlation coefficient and the distance between images can be obtained from a basic experiment using a phantom performed in advance. That is, the value of the cross-correlation coefficient calculated by the cross-correlator 47 is input to the look-up table 38, and the look-up table 38 outputs the inter-image distance.

In this case, the reference image (generally the first image taken) is stored as the first measurement B-mode image in the frame memory A36-1, and this image is stored in the frame memory B36-2. The relative distance of the second measurement B-mode image is calculated. The image control circuit 24 reads the output data of the look-up table 38, and based on the value, that is, the inter-image distance, the three-dimensional image memory 2
Access to the first diagnostic image and the second diagnostic image corresponding to the first measurement B-mode image and the second measurement B-mode image stored in The second diagnostic image is reset for the image. The image control circuit 24 also has a simple arithmetic function such as MIP processing or volume rendering processing.

The operator gives an instruction for a three-dimensional display method from the input unit 9 to the newly constructed three-dimensional image data, and this instruction is inputted to the image control circuit 24 via the system control unit 8 and, for example, 3 Image data of an arbitrary cross section requested by the operator is read out from the three-dimensional image data and is temporarily stored in the buffer memory 26. The image data in the buffer memory 26 is further sent to the display image memory 34 of the display image generation unit 7 by the image control circuit 24.

The display image generating section 7 has a display image memory 34.
And a D / A converter 38 and a display circuit 35. The display image memory 34 is a B-mode image or a color Doppler image displayed on an image display monitor of the display unit 10 described later,
Furthermore, image data such as a three-dimensional image is once stored. The image data stored in the display image memory 34 is read by an instruction from the system control unit 8, D / A converted in the display circuit 35, and then converted into a television format.

The system control unit 8 controls each unit such as the ultrasonic wave transmitting unit 2, the ultrasonic wave receiving unit 3, the three-dimensional image generating unit 5, the display image generating unit 7 and the whole system based on the signal from the operation panel 28. Control. Particularly, in the three-dimensional image generation unit 5, the operator's command is sent to the image control circuit 24.
To control the reconstruction of the three-dimensional image and the setting of the display section.

The input unit 9 is provided with a keyboard, a trackball, a mouse, etc. on the operation panel, and is used by the operator of the apparatus to input patient information and imaging conditions of the apparatus. In addition, various image quality condition settings, or enlargement or reduction of the image after three-dimensional image reconstruction, and instructions such as rotation are performed.

The display unit 10 is equipped with a color monitor,
Various image data such as a B-mode image, a color Doppler image, and a three-dimensional image are displayed.

Next, the procedure of image data acquisition and image data position setting according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3A is a flowchart showing the procedure for collecting image data, and FIG. 3B is a flowchart showing the procedure for setting the position of image data. The operator brings the tip (ultrasonic wave transmitting / receiving surface) of the ultrasonic probe 1 into contact with the body surface of the subject, and sets the initial position P1 in the slice direction (step S1).

During transmission of ultrasonic waves, the rate pulse generator 11 synchronizes with the control signal from the system controller 8 and sends to the transmission delay circuit 12 rate pulses for determining the repetition period of ultrasonic pulses radiated into the subject. Supply. The transmission delay circuit 12 is composed of almost the same number of independent delay circuits as the ultrasonic transducers used for transmission, and a delay for converging ultrasonic waves to a predetermined depth in order to obtain a narrow beam width in transmission. Time and a delay time for transmitting ultrasonic waves in a predetermined direction (θ1) are given to the rate pulse, and this rate pulse is supplied to the pulser 13.

The pulsar 13 has almost the same number of independent drive circuits as the ultrasonic transducers used for transmission, and the ultrasonic transducer 1 is driven by the ultrasonic transducer drive pulses generated by the drive of the rate pulse. The built-in ultrasonic transducer is driven to emit ultrasonic pulses into the subject.

A part of the ultrasonic waves radiated into the subject is reflected by the boundary surface between the organs or tissues in the subject having different acoustic impedances. When this ultrasonic wave is reflected by a moving reflector such as a heart wall or blood cells, the ultrasonic frequency undergoes Doppler shift.

The ultrasonic waves reflected in the tissue of the subject are received by the same ultrasonic transducer as at the time of transmission and converted into electric signals. This received signal is amplified by the same number of independent preamplifiers 14 as the ultrasonic transducers used for reception, and sent to the reception delay circuit 15. The reception delay circuit 15 has a delay time for converging an ultrasonic wave from a predetermined depth in order to obtain a narrow beam width in reception, and a strong reception directivity in a predetermined direction (θ1) with respect to the ultrasonic beam. A delay time for receiving the signal is given to the output signal of the preamplifier 14 and then sent to the adder 16. The adder 16 is the preamplifier 14,
A plurality of reception signals input via the reception delay circuit 15 are added and combined into one reception signal, which is then supplied to the B-mode processing unit 4 and the Doppler mode processing unit 6 (step S
2).

When collecting a diagnostic B-mode image,
The output of the adder 16 is a switch (SW) of the band limiting unit 40.
After being sent to the B-mode processing unit 4 via 18, and subjected to logarithmic conversion, envelope detection, and A / D conversion, the display image generation unit 7
Is stored in the display image memory 34 (step S
3).

When the collection and storage of the diagnostic B-mode image data in the θ1 direction is completed, the measurement B-mode image data is collected with the ultrasonic transmission / reception direction fixed.
That is, the delay times of the ultrasonic transmitter 2 and the ultrasonic receiver 3 are set in the same manner as when collecting the diagnostic B-mode image data, and the adder 16 supplies the output signal to the filter 17 of the band limiting unit 40. The high frequency component of the received signal is removed.
The output of the filter 17 is supplied to the B-mode processing unit 4 via the switch 18, and is subjected to logarithmic conversion, envelope detection, and A / D conversion in the same manner as the above-described diagnostic B-mode image data, and then three-dimensionally. Image memory 2 for distance measurement of the image generator 5
2 is stored (step S4).

On the other hand, in the Doppler mode processing unit 6, in order to obtain the Doppler shift of the ultrasonic wave reception signal, the system control unit 8 continuously transmits and receives ultrasonic waves a plurality of times in the same direction. FFT (Fast-F
ourier-Transform) analysis.

The Doppler mode processing unit 6 applies a mixer 29 and an LPF (low pass filter) to the output of the adder 16.
Quadrature detection using 30 to convert to complex signal, A /
After D conversion, it is stored in the Doppler signal storage circuit 50. The same signal processing is performed on the reception signals obtained by scanning a plurality of times in the same transmission / reception direction, and the FFT is performed on the plurality of reception signal data stored in the Doppler signal storage circuit 50.
The analyzer 32 determines the frequency spectrum. Further, the computing unit 33 calculates the center value (average velocity of blood flow) and the variance value (state of turbulence of blood flow) of the frequency spectrum output from the FFT analyzer 32, and the system control unit 8 outputs the calculated value. The result is read and stored in the display image memory 34 together with the diagnostic B-mode image (step S5).

Next, the same procedure as above is performed by scanning in the N direction, which is performed by deflecting the ultrasonic wave transmitting / receiving direction by Δθ stepwise by θ1 + (n−1) Δθ (n = 2 to N). Ultrasonic waves are transmitted and received, and the inside of the subject is scanned in real time (see FIG. 5A described later). At this time, the system control unit 8 controls the transmission delay circuit 12 according to the control signal.
While sequentially switching the delay time of the reception delay circuit 15 according to the ultrasonic transmission / reception direction, each of the diagnostic B-mode image data, the color Doppler image data, and the measurement B-mode image data is collected (steps S3 to S7). ).

The system control unit 8 synthesizes the diagnostic B-mode image data and the color Doppler image data obtained in step S6 and step S7 and stores them in the display image memory 34. If configured, it is displayed as a diagnostic image on the TV monitor of the display unit 10 via the display circuit 35. Further, the diagnostic image data stored in the display image memory 34 is stored in the 3D image memory 25 of the 3D image generation unit 5.

On the other hand, for the B mode image data for measurement, the three-dimensional image generation unit 5 is sequentially operated while changing the transmission / reception direction.
Is stored in the image memory 22 for distance measurement, and one B-mode image for measurement is generated in the image memory 22 for distance measurement.

FIG. 4 shows the characteristics of the filter 17 of the band limiting section 40. Ultrasonic waves used for ultrasonic diagnosis require a short pulse wave shown in FIG. 4A in order to ensure distance resolution (radiation direction resolution). Therefore, the received signal from the inside of the subject can be approximately considered as a combination of similar short pulse waves, and its frequency spectrum shows a wide band characteristic as shown in FIG. 4 (b) b-1. The filter 17 of the band limiting unit 40 is the ultrasonic receiving unit 3
For the received signal from within the subject supplied via
Only the low frequency component is extracted by the high frequency cutoff characteristic (FIG. 4 (b) b-2) (FIG. 4 (b) b-3).

That is, in the signal for generating the measurement B-mode image, the high-frequency component of the ultrasonic reception signal is removed by passing through the filter 17, and therefore, the measurement signal stored in the distance measurement image memory 22 is used. The B-mode image is obtained by imaging the same region with a low frequency component as compared with the diagnostic B-mode image stored in the three-dimensional image memory 25.

Next, the operator manually moves the ultrasonic probe 1 in a direction substantially perpendicular to the image plane of the two-dimensional image (that is, the slice direction) as shown in FIG. collect. However, in the case where the ultrasonic probe 1 for sector scanning is used as in this embodiment, the tip of the ultrasonic probe 1 is about 30 times as a fan by the translational scanning as shown in FIG. In many cases, the tilt scan FIG. 5B is performed at a degree. Incidentally, in the clinical setting, about 100 images for the B mode only and about 25 to 50 images for the combined image with the color Doppler mode are required for the tilt scan of about 30 degrees.

The operator touches the body surface of the subject with the tip of the ultrasonic probe 1, which is the ultrasonic wave transmitting / receiving surface, while making contact with the body surface of the subject about 30
Scan the range of degrees manually at an almost constant speed,
M (about 50) B-mode and color Doppler mode composite images are collected in the slice direction. System control unit 8
Sequentially adds the indexes of P1 to PM to these M images and stores them in the three-dimensional image memory 25. On the other hand, the indexes P1 to PM are similarly added to the M measurement B-mode images obtained in the distance measurement mode and are stored in the distance measurement image memory 22. (Steps S2 to S9).

Next, M stored in the three-dimensional image memory 25
Position information is given to one diagnostic image, and the image plane position is reset in the three-dimensional image memory 25 based on this position information.

The image control circuit 24 collects in parallel with the diagnostic B-mode image in order to give position information to the diagnostic ultrasonic image, and stores M number of measuring images stored in the distance measuring image memory 22. Of the B-mode images, the first image (image A with index P1) and the image adjacent to this image (image B with index P2) are read out and sent to the image position detector 23 (step S11).

In the image position detector 23, the image A is temporarily stored in the frame memory A36-1 and the image B is temporarily stored in the frame memory B36-2. The image control circuit 24 includes a frame memory A36-1 and a frame memory B36-2.
The data of the image A and the image B stored in is read and input to the correlation processor 37, and the correlation processor 37 calculates the cross-correlation coefficient for the input images A and B.

The method of calculating the cross-correlation coefficient for the purpose of measuring the distance between images will be described below. First, prior to the calculation of the cross-correlation coefficient between the image A and the image B, the correction of the deviation in the image plane direction between the two images will be described with reference to FIG. To accurately calculate the cross-correlation coefficient, image A and image B
However, it is desirable to reduce the deviation in the image plane direction as much as possible.

Now, as shown in FIG. 6A, the signal intensity of the pixel (p, q) of the image A is A (p, q), and similarly, the signal intensity of the pixel (p, q) of the image B is B. With (p, q), it is possible to detect the deviation in the image plane direction of the images A and B from the following cross-correlation function γ _AB (k, s). Ie

[Equation 1] As a result of this calculation, as shown in FIG. 6B, k = k1, s
= S1 has the maximum value of γ _AB (k, s), it means that the image is displaced by k1 in the p direction and by s1 in the q direction. However, although FIG. 6B shows only the case where k is a parameter, the same can be obtained when s is used as a parameter.

Next, the cross-correlation coefficient is calculated in consideration of the shift between the images obtained by the above calculation. That is, A (p, q) of image A and B (p + k1, q + s of image B
The cross-correlation coefficient α _AB for 1) is obtained by the following formula.

[0064]

[Equation 2] FIG. 7 shows an area in which cross-correlation processing is performed when the actual inter-image distance is performed. Although the shift in the image plane direction has been described above, in the case of a tilt scan, the distance between images increases as the distance from the ultrasonic probe 1 increases. Furthermore, a twist may occur between the two images.

For these reasons, the image A and the image B are
On each image of at least 3 as shown in FIG.
One cross-correlation coefficient calculation area is set, the image plane direction deviation correction described in FIG. 6 is performed in each of the areas, and the cross-correlation coefficient α _AB is calculated.

The state of twist can be grasped from the cross-correlation coefficient between the calculation area B and the calculation area C in FIG. 7, and the twisting can be seen from the cross-correlation coefficient between the calculation area A and the calculation area B or the calculation area A and the calculation area C. It is possible to estimate the angle (step S12).

Regarding the setting of the calculation area, the position information of the calculation area is stored in the system control unit 8 in advance, and the area is automatically set when the distance measurement mode command is input from the input unit 9. However, this calculation region needs to be set by eliminating the influence of a strong reflection signal from blood vessels, bones, and body gas.

For this reason, in this embodiment, the operator observes the diagnostic image on the display unit 10 and sets a region considered to be applicable by using the mouse of the input unit 9 or the like. The input unit 9 sends the position information of the calculation area set at this time to the image control circuit 24 via the system control unit 8, and the image control circuit 24 sends this position information to the correlation processor 37. The cross-correlator 37 uses the position information of the calculation area and the image data of the image A and the image B read from the frame memory A36-1 and the frame memory B36-2, based on the above formulas (1) and (2). The correlation coefficient α _AB is calculated.

Next, the correlation processor 37 determines the cross-correlation coefficient α _AB
The calculation result of is input to the lookup table 38. At this time, the image control circuit 24 reads the value of the inter-image distance output from the look-up table 38 (step S13), and based on this inter-image distance, the diagnostic image stored in the three-dimensional image memory 25. Of these, the coordinates of the diagnostic images AA and BB having the same index P1 and index P2 as the images A and B are set. This image AA is an image serving as a reference in setting the position of the diagnostic image acquired in the slice direction.
The coordinates of the image BB are set by adding the distance between the images to the coordinates of A (step S14).

Similarly, the inter-image distance is obtained for the image B in the distance measuring image memory 22 and the image C adjacent thereto, and 3 corresponding to the image C based on the value of the inter-image distance. The coordinates of the image CC in the three-dimensional image memory 25 are the image B.
It is set based on B.

In the same manner, two adjacent measuring Bs are used.
By sequentially obtaining the inter-image distance for each mode image and setting the coordinates of the diagnostic image based on the inter-image distance, three-dimensional image data having an accurate positional relationship is constructed in the three-dimensional image memory 25 ( Steps S12 to S1
6). In addition, when a space is generated in the three-dimensional image memory 25 as a result of resetting the position of each diagnostic image by the above procedure, it is necessary to perform interpolation processing by the surrounding image data.

The operator designates an arbitrary desired image section on the three-dimensional image memory 25 by using the mouse from the input section 9 to observe the ultrasonic image of the designated section on the display section 10. can do. At this time, the cross-section designation signal input from the input unit 9 is sent to the image control circuit 24 via the system control unit 8. Image control circuit 24
Reads out image data from the three-dimensional image memory 25 based on the address corresponding to the designation signal, temporarily stores it in the buffer memory 26, and then displays it on the TV monitor of the display unit 10 via the display image generation unit 7 ( Step S1
7).

Further, when observing a three-dimensional image of blood flow and blood vessels, the image control circuit 24 operates only the color Doppler image data in the three-dimensional image memory 25 in accordance with the blood vessel three-dimensional display command input by the operator from the input unit 9. Can be displayed on the display unit 10 via the buffer memory 26 and the display image generation unit 7 after the projection image process which is generally performed such as MIP process or volume rendering process is performed. .

The data of the lookup table 38 used in this embodiment can be created in advance by a basic experiment using an ultrasonic phantom.
For example, the ultrasonic probe 1 is moved in the slice direction by a predetermined distance, the cross-correlation coefficient is calculated from two phantom images obtained before and after the movement, and the relationship between the movement distance and the cross-correlation coefficient is provided as a table. In this case, it is desirable to use an ultrasonic phantom in which fine particles to be ultrasonic scatterers are mixed in an agar gel.

The feature of the first embodiment of the present invention described above is that from the cross-correlation process using the measurement B-mode image generated by the low frequency component of the ultrasonic reception signal from the inside of the subject to the inter-image processing. This is to obtain the distance, and its effect will be described with reference to FIG. FIG. 8A shows the speckle pattern A of the measurement B-mode image and the speckle pattern B of the diagnostic image. Further, FIG. 8B compares the relationship between the inter-image distance obtained by the measurement B-mode image and the cross-correlation coefficient with the case of the diagnostic image. As shown in FIG. 8, the size of the speckle pattern generated on the measurement B-mode image generated from a narrow band and low frequency component increases, and a rapid change occurs with a change in the inter-image distance. Absent.

That is, according to the first embodiment, the inter-image distance is reduced by the cross-correlation process of the measurement B-mode image generated by the low frequency component of the ultrasonic reception signal received from the inside of the subject. The cross-correlation coefficient can be stably obtained even if it is slightly increased, and therefore, there is an advantage that the inter-image distance can be estimated more accurately. In particular, since it is possible to estimate the inter-image distance even in a region where the image interval is widened as in the case of a tilt scan, accurate three-dimensional image data can be constructed.

(Modified Example of First Embodiment) Next, a modified example of the first embodiment will be described with reference to FIG. In this modified example, a case where the first embodiment is applied to a harmonic imaging diagnostic method which has been put into practical use in recent years will be described. With harmonic imaging, ultrasonic waves radiated into the subject are selected by receiving a harmonic component of a frequency double that generated by the ultrasonic non-linear characteristics of the subject's tissue, and used for diagnostic B
This is a method of generating a mode image, and since an artifact on the image is reduced, an ultrasonic image with excellent resolution can be obtained.

FIG. 9A is a block diagram of the band limiting unit 40 in this modified example, and FIG. 9B is a block diagram of the band limiting unit 4.
The frequency spectrum of the ultrasonic reception signal input to 0 is shown. As shown in FIG. 9B, the ultrasonic wave reception signal reflected by the tissue inside the object and received by the ultrasonic probe 1 includes not only the fundamental wave component having the frequency spectrum of the center frequency f2 but also the object It contains a second harmonic component of the center frequency f3 that is newly generated under the influence of the ultrasonic nonlinearity of the tissue. When this embodiment is applied to the harmonic imaging method, a diagnostic image is generated using the second harmonic component, and a measurement B-mode image is generated using the fundamental component.

When collecting diagnostic images, the switch 43 is turned on and the switch 44 is turned off, and the ultrasonic wave reception signal supplied from the ultrasonic wave reception unit 3 is BPF.
Only the second harmonic component is sent to the B-mode processing unit 4 through the (band pass filter) 41. The B-mode processing unit 4 subjects the second harmonic component to signal processing such as logarithmic conversion, envelope detection, and A / D conversion, and is temporarily stored in the display image memory 34 of the display image generation unit 7. .

On the other hand, when collecting the measurement B-mode image, the switch 43 is OFF and the switch 44 is ON.
After changing to the state, only the fundamental wave component of the ultrasonic reception signal is sent to the B-mode processing unit 4 through the LPF (low pass filter) 42. In this B-mode processing unit 4, the fundamental wave component is subjected to the same signal processing as the second harmonic component,
It is stored in the distance measurement image memory 22 of the three-dimensional image generation unit 5.

For the ultrasonic wave reception signal obtained by scanning the inside of the subject in real time by sequentially changing the transmitting and receiving directions of the ultrasonic wave, the diagnostic B-mode image data generated from the second harmonic component is temporarily displayed. The image is stored in the image memory 34, and after being combined with the color Doppler image data described above, the combined image is stored in the three-dimensional image memory 25. Similarly, the measurement B-mode image data generated from the fundamental wave component of the ultrasonic reception signal is sequentially stored in the distance measurement image memory 22.

The following procedure is the same as the procedure of the first embodiment shown in FIG. 3 and its explanation is omitted.

Since the second harmonic component is positively imaged in this harmonic imaging method, the center frequency f2 of the fundamental wave component is lower than the center frequency f0 of the fundamental wave component in the conventional imaging method shown in FIG. . Therefore, also in this case, since it is possible to use the measurement B-mode image generated by the frequency component lower than the diagnostic image, the cross-correlation coefficient can be stably obtained even if the inter-image distance is slightly increased. The distance between images can be estimated based on this cross-correlation coefficient. Particularly, according to the modified example of the first embodiment, the distance between the ultrasonic images arranged in the slice direction is estimated by effectively utilizing the fundamental wave component that has not been used in the conventional harmonic imaging method. It has the advantage of being able to.

(Second Embodiment) In the second embodiment of the present invention described below, the measurement B-mode image used for estimating the relative distance between ultrasonic images in the slice direction is a diagnostic B-mode image. It is characterized by being generated by an ultrasonic beam width wider than the image.

A procedure of image data acquisition and image data position setting according to the second embodiment of the present invention will be described with reference to FIGS. However, FIG. 10 is a block diagram showing a schematic configuration of the ultrasonic diagnostic apparatus according to the second embodiment, and FIG.
FIG. 11A is a flow chart showing the procedure for collecting image data, and FIG. 11B is a flow chart showing the procedure for setting the position of image data.
The Doppler mode processing unit 6 is similar to that of the first embodiment, and therefore its explanation is omitted.

The operator brings the tip (ultrasonic wave transmitting / receiving surface) of the ultrasonic probe 1 into contact with the body surface of the subject, and sets the initial position P1 in the slice direction (step S21).

In collecting diagnostic image data, the rate pulse generator 11 supplies rate pulses to the transmission delay circuit 12 in accordance with the control signal from the system controller 8. The transmission delay circuit 12 is composed of NT independent delay circuits of the same number as the NT ultrasonic transducers used for transmission, and converges the ultrasonic waves to a predetermined depth to obtain a narrow transmission beam width. And a delay time for transmitting ultrasonic waves in a predetermined direction (θ1) to scan the inside of the subject are given to the rate pulse, and this rate pulse is supplied to the pulser 13.

The pulser 13 has NT independent driving circuits, and the ultrasonic transducer driving pulses generated by being driven by the rate pulse generate the ultrasonic vibrations of the NT ultrasonic transducers built in the ultrasonic probe 1. The child is driven to emit an ultrasonic pulse into the subject.

The ultrasonic wave reflected by the tissue in the subject is received by the ultrasonic transducer and converted into an electric signal. This received signal is amplified by the NR independent preamplifiers 14 of which the number is the same as that of the NR ultrasonic transducers used for reception, and is further sent to the NR reception delay circuits 15.

The reception delay circuit 15 has a delay time for converging ultrasonic waves from a predetermined depth to obtain a narrow reception beam width and a predetermined direction (θ) with respect to the reception ultrasonic beam.
After giving a delay time for receiving with strong reception directivity to 1) to the output signal of the preamplifier 14, the adder 16
Send to. The adder 16 adds and combines the NR received signals input through the NR channel preamplifier 14 and the reception delay circuit 15 and combines them into one received signal, and then B
It is sent to the mode processing unit 4. (Step S22) The output of the adder 16 in the B mode processing unit 4 is logarithmically converted, enveloped, and A / D converted, and then stored in the display image memory 34 of the display image generation unit 7 (Step S23). ).

When the storage of the diagnostic B-mode image data in the θ1 direction is completed, the measurement B-mode image data is collected while the ultrasonic wave transmission / reception direction is fixed at θ1.
In collecting the measurement B-mode image data, the system control unit 8 sets the number of channels used for the ultrasonic wave transmitting unit 2 and the ultrasonic wave receiving unit 3 to NT0 and NR0, respectively (step S24).

The rate pulse generator 11 supplies rate pulses to NT0 of the NT transmission delay circuits 12 under the control of the system controller 8. However, NT0 <N
T. Further, the transmission delay circuits 12 of NT0 units are for delay time for converging ultrasonic waves to a predetermined depth and for transmitting and scanning ultrasonic waves in a predetermined direction (θ1) in order to obtain a narrow beam width in transmission. The delay time is given to the rate pulse and is supplied to the NT0 pulsers 13 connected to it.

The pulsar 13 selectively drives NT0 ultrasonic transducers arranged adjacently by the ultrasonic transducer drive pulse generated by being driven by the rate pulse, and radiates the ultrasonic pulse into the subject.

On the other hand, in reception, this reception signal is amplified by NR independent preamplifiers 14 of which the number is the same as that of NR ultrasonic transducers used for reception, and is further sent to NR reception delay circuits 15. .

The reception delay circuit 15 has a delay time for converging an ultrasonic wave from a predetermined depth in order to obtain a narrow beam width in reception and a predetermined direction (θ) with respect to the ultrasonic beam.
The delay time for receiving with strong reception directivity in 1) is given to the reception signal and then sent to the adder 16. Adder 1
Reference numeral 6 denotes a preamplifier 14 and a reception delay circuit 15 for these NR channels based on the control signal from the system control unit 8.
NR0 (MR0
The reception signals of the <NR) channels are added and combined to be combined into one reception signal, which is then sent to the B-mode processing unit 4. However, the received signal of the NR0 channel corresponds to the received signal from the NR0 ultrasonic transducers arranged adjacently in the central portion of the NR ultrasonic transducers used for reception.

The data of the number of used channels NT0 and NR0 at the time of transmission and reception at the time of collecting the B mode image for measurement is previously stored in a storage circuit (not shown) of the system control unit 8.

In the B mode processing unit 4, the output of the adder 16 is logarithmically converted, enveloped, and A / D converted, and then 3
It is stored in the distance measurement image memory 22 of the three-dimensional image generation unit 5 (step S25).

Next, the ultrasonic wave transmission / reception direction is sequentially updated by Δθ while the scanning in the N direction is performed by deflecting to θ1 + (n−1) Δθ (n = 2 to N), and the same procedure as above is performed. Real-time scanning is performed inside the subject by transmitting and receiving sound waves. At this time, the system control unit 8 sequentially switches the delay times of the transmission delay circuit 12 and the reception delay circuit 15 according to the control signal in accordance with the ultrasonic wave transmission / reception direction, and the diagnostic B-mode image data and the measurement B-mode image data. To collect.

Next, the system control section 8 sequentially stores the obtained diagnostic B-mode image data in the display image memory 34, and if one sheet of diagnostic image data is constructed, it is sent via the display circuit 35. The image is displayed as a diagnostic image on the TV monitor of the display unit 10. Further, the image data stored in the display image memory 34 is stored in the 3D image memory 25 of the 3D image generation unit 5.

On the other hand, the measurement B-mode image data is also stored as one image in the distance measurement image memory 22 of the three-dimensional image generation section 5 (steps S23 to S27).

Next, the ultrasonic probe 1 is manually moved in the slice direction to collect M ultrasonic images. The operator touches the body surface of the subject with the tip of the ultrasonic probe 1, which is the ultrasonic transmitting / receiving surface, and manually scans the range of about 30 degrees at an almost constant speed to scan M slices in the slice direction. Collect B-mode images. The system control unit 8
3 by adding indexes P1 to PM to these images
The measurement images are sequentially stored in the three-dimensional image memory 25, and the M measurement B-mode images obtained in the distance measurement mode are also stored in the distance measurement image memory 22 with the same indexes P1 to PM added (steps S22 to S2).
9).

Next, the image control circuit 24 gives the positional information to the diagnostic B-mode image, and the first image of the M measuring B-mode images stored in the distance measuring image memory 22 is displayed. The (image A having the index P1) and the second image (image B having the index P2) adjacent to this image are read out and sent to the image position detecting section 23 (step 31).

These two images are sent to the correlation processor 37 of the image position detector 23, and the cross-correlation coefficient between the images is calculated. At this time, areas for calculating the cross-correlation coefficient are set in at least three regions on each image, and the cross-correlation coefficient is calculated in each of the areas (step 32). Further, the correlation processor 37 inputs the obtained cross-correlation coefficient to the look-up table 38 of the image position detection unit 23.

The image control circuit 24 reads the value of the inter-image distance output from the look-up table 38 (step S33), and among the diagnostic images stored in the three-dimensional image memory 25 based on this distance. , Coordinates of the diagnostic image AA and the image BB having the same indexes P1 and P2 as the measurement image A and the image B are set. At this time, the coordinates of the image BB are set by adding the inter-image distance to the coordinates of the reference image AA (step S
34).

Similarly, the inter-image distance is obtained for the image B in the distance measuring image memory 22 and the image C adjacent thereto, and 3 corresponding to the image C based on the value of the inter-image distance. The coordinates of the image CC in the three-dimensional image memory 25 are the image B.
It is set based on B.

In this manner, the inter-image distance is sequentially obtained for two adjacent measurement images, and the coordinates of the diagnostic image are sequentially set on the basis of the inter-image distance. The three-dimensional image data is constructed in the three-dimensional image memory 25 (steps S32 to S36).

The operator designates a desired image slice on the three-dimensional image memory 25 with the mouse from the input unit 9 to observe the ultrasonic image of the designated slice on the display unit 10. can do. At this time, the cross-section designation signal input from the input unit 9 is sent to the image control circuit 24 via the system control unit 8. Image control circuit 24
Reads out image data from the three-dimensional image memory 25 based on the address corresponding to the designation signal, temporarily stores it in the buffer memory 26, and then displays it on the TV monitor of the display unit 10 via the display image generation unit 7 ( Step S3
7).

As described above, in the second embodiment of the present invention, the number of channels used in transmission or reception (equivalently used for transmission and reception is compared with the case of collecting normal diagnostic images. B-mode images for measurement are collected with the number of ultrasonic transducers or apertures reduced, and cross-correlation processing between images is performed using this image to obtain the inter-image distance.

FIG. 12A shows the relationship between the number of ultrasonic transducers and the beam width at the convergence point. The beam width is inversely proportional to the number of ultrasonic transducers if the ultrasonic transducer spacing is uniform. .

FIG. 12 (b) schematically shows the relationship between the beam width and the speckle pattern. From FIG. 12, when the beam width is large, the range in which the beam width intersects is relatively large even if the beams are moved by the same distance in the slice direction, and thus the probability that signals from the same scatterer are included is high.
Therefore, the correlation coefficient can be stably obtained even when the inter-image distance is somewhat large.

That is, according to the second embodiment, the same effect as that of the first embodiment can be obtained by using the measurement B-mode image obtained by expanding the beam width of the ultrasonic beam during transmission and reception. Moreover, since this method can be performed by the control signal sent from the system control unit 8 to the ultrasonic wave transmitting unit 2 or the ultrasonic wave receiving unit 3, there is an advantage that it is not necessary to add a filter or a switch.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments,
It can be modified and implemented. FIG. 13 shows the scanning density and the scanning range of the ultrasonic image. In the above embodiment, the ultrasonic scanning range and the scanning density (FIG. 13B) in the measurement B-mode image are shown in FIG.
Although the same setting was made as in the case of the diagnostic image shown in (a),
The scanning density of the measurement B-mode image may be made coarse as shown in FIG. 10C, or the scanning range of the measurement B-mode image as shown in FIG. 10D. May be narrowed.

The band limiting unit 40 has described the case where the filter 17 is switched by the switch 18 to serially collect the diagnostic B-mode image and the measurement B-mode image, but the present invention is not limited to this, and the diagnostic B-mode image is not limited to this. If the B-mode processing unit and the measurement B-mode processing unit are independently provided, the diagnostic B-mode image data and the measurement B-mode image data can be simultaneously acquired in a short time.

Further, in the above embodiment, the method of reducing the number of ultrasonic transducers used for transmission and reception in order to widen the beam width of the ultrasonic beam has been described, but other methods may be used, for example, Similar effects can be obtained even if the convergence distance of the transmission / reception beam is set far from the ultrasonic probe 1 or non-convergence. Further, the ultrasonic beam width may be expanded only for either transmission or reception.

On the other hand, in the above embodiment, the method of calculating the cross-correlation coefficient is shown as a method of quantifying the similarity between images in the estimation of the distance between images, but the method is not limited to this method. For example, the subtraction may be performed on a pixel-by-pixel basis for two image signals, and the sum of the absolute values of the subtraction values or entropy may be obtained and evaluated.

Further, in the embodiment, the inter-image distance is obtained based on the image data, but the received signal before detection and the IQ signal (Inverse-Quadrature) after quadrature detection are obtained.
The distance may be obtained using Signal) or the like.

Further, instead of synthesizing the image data output from the B mode processing unit 4, the Doppler mode processing unit 6
The average velocity, the variance, or the power value of the blood flow of each cross section output from is synthesized based on the output of the image position detection unit 23,
You may make it generate | occur | produce three-dimensional image data of the value of average velocity, dispersion | distribution, or power of a blood flow. In the analysis of the Doppler signal used in this case, an MTI filter and an autocorrelation processing circuit may be used instead of the FFT analyzer 32 to obtain the blood flow velocity, dispersion, and power.

[0118]

According to the present invention, a plurality of ultrasonic images having relative position information can be obtained without mounting a position sensor on the ultrasonic probe, so that three-dimensional image data can be easily obtained. And it becomes possible to collect accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an entire ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an image position detection unit of the present invention.

FIG. 3 is a diagram showing a flowchart of an image data collection procedure according to the first embodiment of the present invention.

FIG. 4 is a diagram showing band limitation in the first embodiment of the present invention.

FIG. 5 is a diagram showing a method of collecting image data in a slice direction according to the first embodiment of the present invention.

FIG. 6 is a diagram showing inter-image cross-correlation processing according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a cross-correlation processing region according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between a speckle pattern and a cross-correlation coefficient according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a modified example of the first embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention.

FIG. 11 is a diagram showing a flowchart of an image data collection procedure according to the second embodiment of the present invention.

FIG. 12 is a diagram showing a relationship between an ultrasonic beam width and a speckle pattern according to the second embodiment of the present invention.

FIG. 13 is a diagram showing an ultrasonic scanning density and a scanning range in the first and second embodiments of the present invention.

[Explanation of symbols]

1 ... Ultrasonic probe 2 ... Ultrasonic transmitter 3 ... Ultrasonic receiver 4 ... B mode processing unit 5 ... three-dimensional image generation unit 6 ... Doppler mode processing unit 7 ... Display image generation unit 8 ... System control unit 9 ... Input section 10 ... Display 17 ... Filter 22 ... Image memory for distance measurement 23 ... Image position detector 24 ... Image control circuit 25 ... Three-dimensional image memory 26 ... Buffer memory 36 ... Frame memory 37 ... Correlation processor 38 ... Look-up table 40 ... Band limiting unit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4C301 BB13 EE07 EE13 GD02 JB28                       JB38 JC11 KK19                 4C601 BB03 EE04 EE11 GA17 GA18                       GA21 JB28 JB31 JB34 JB41                       JC15 JC25 JC33 KK21                 5B057 AA09 BA05 CA08 CA13 CA16                       CB08 CB13 CB16 DA07 DB03                       DB09 DC02 DC32                 5L096 AA06 AA09 BA06 BA13 FA66                       FA69 HA07 JA03

Claims (10)

[Claims] 1. An ultrasonic probe provided with an ultrasonic transducer for transmitting and receiving ultrasonic waves, and first data and a second data based on an ultrasonic echo signal output from the ultrasonic probe.
Signal processing means for generating the data, distance calculating means for obtaining the distance based on the similarity between the first and second data, and three-dimensional image data based on the output of the ultrasonic probe and the distance. An ultrasonic diagnostic apparatus comprising: means for generating. 2. An ultrasonic probe having an ultrasonic transducer, means for generating ultrasonic image data based on the output of the ultrasonic transducer, and distance measurement based on the output of the ultrasonic transducer. A unit for generating data, a first storage unit for sequentially storing a plurality of ultrasonic images obtained by moving the ultrasonic probe, and a plurality of distance measuring units obtained by moving the ultrasonic probe Second storage means for sequentially storing the use data and a plurality of predetermined images read from the second storage means, and the relative position thereof is estimated based on signal processing for evaluating the similarity between these images. Image position estimating means, and means for rearranging the first ultrasonic image stored in the first storage means based on relative position information obtained by the image position estimating means to generate three-dimensional image data. Have An ultrasonic diagnostic apparatus characterized by the above. 3. A band limiting means is further provided, and the distance measuring data is generated by extracting a low frequency component of a reception signal obtained by the ultrasonic probe by the band limiting means. 2. The ultrasonic diagnostic apparatus according to 2. 4. A beam width control means for controlling an ultrasonic beam width is further provided, and at least one of a beam width of a transmission beam and a beam width of a reception beam used for collecting the distance measurement data is the beam. The ultrasonic diagnostic apparatus according to claim 2, wherein the beam width is made wider than the beam width at the time of acquiring the ultrasonic image data by the width control means. 5. The ultrasonic probe comprises a plurality of ultrasonic transducers arranged one-dimensionally, and the ultrasonic beam width used when collecting the distance measurement data is used by the ultrasonic beam width control means. The ultrasonic diagnostic apparatus according to claim 4, which is performed by controlling the number of the ultrasonic transducers. 6. The ultrasonic beam width at the time of collecting the distance measurement data is set by changing a convergence point of the ultrasonic beam by a beam width control means for controlling the ultrasonic beam width. The ultrasonic diagnostic apparatus according to claim 4. 7. The super processing according to claim 2, wherein the signal processing between images in said image position estimating means uses a plurality of images read from said second storage circuit and quantifies the similarity. Sound wave diagnostic equipment. 8. The ultrasonic diagnosis according to claim 7, wherein the image position estimating means includes the quantifying means and a converting means for converting a result obtained by the quantifying means into an inter-image distance. apparatus. 9. The ultrasonic diagnostic apparatus according to claim 7, wherein a cross-correlation coefficient is calculated as the quantification means. 10. Further comprising an input means and a display means,
The ultrasonic diagnostic apparatus according to claim 2, wherein image data at a predetermined position is extracted from the three-dimensional image data based on an instruction signal from the input means and is displayed by the display means.