JPH10295691A - Ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the motion of an ultrasonic probe when manual scan is made with ultrasonic probe and construct a three-dimensional image using the obtained information. SOLUTION: This ultrasonic diagnostic device includes an ultrasonic probe 30 and a magnetic field generation part 34 which generates a magnetic field having directionality, and the generated field is sensed by a sensing part 36 furnished in the probe 30. Thereby the three-dimensional coordinates and attitude of the probe 30 are sensed. Each time the probe 30 makes a certain amount of motion, a synchronizing pulse 206 is produced, and a three-dimensional image is constructed using the echo data of the scanning surface taken in at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ultrasonic diagnostic apparatus, and more particularly, to an ultrasonic diagnostic apparatus in which an ultrasonic probe is manually scanned.

[0002]

2. Description of the Related Art In a two-dimensional tomographic image display (so-called B-mode display) in a conventional ultrasonic diagnostic apparatus, a cross section in a living body is displayed as a black and white gray-scale image. However, since only the cut surface of the tissue to be observed is expressed, it is difficult to recognize and grasp the tissue three-dimensionally on the image. On the other hand, an apparatus that transmits and receives ultrasonic waves to and from a three-dimensional region in a living body to form a three-dimensional image of a tissue is being put into practical use. The three-dimensional image is obtained, for example, by shading the tissue surface obtained by performing surface extraction to give a sense of depth, and can express the tissue three-dimensionally. In addition, as a method of imaging a three-dimensional region, an integration method, a projection method, and the like are also known, but an image formed by such a method is planar and has no sense of depth.

In the above-described conventional three-dimensional image processing, all of the echo data captured in a three-dimensional area is temporarily stored in a three-dimensional echo data memory, and then each echo data is processed by software processing or the like. Need to be reconfigured. Therefore, it takes a lot of time to perform a calculation for obtaining one three-dimensional image, and it is extremely difficult to display a three-dimensional image in real time. Further, since the conventional three-dimensional image is basically based on shading of the surface, it has basically been impossible to spatially represent the inside of the tissue through the tissue.

Accordingly, the applicant of the present application has filed a Japanese Patent Application No. 8-185.
No. 781 proposes a new image processing method. Although the principle will be described in detail later, according to such an image processing method, a tissue can be expressed three-dimensionally or transparently, and according to the user's preference, the three-dimensional expression on the tissue surface can be emphasized or the internal tissue can be expressed Can be emphasized.

In this image processing method, a voxel operation (described later) is sequentially performed in a time-series order of the received signal, that is, for each echo data existing along the ultrasonic beam. The voxel calculation is executed until a predetermined end condition is satisfied. Then, the voxel operation value at the end point is associated with the pixel value. Therefore, if the end condition is appropriately set, the voxel operation is terminated near the tissue surface, and a display in which the tissue expression is emphasized can be performed.

[0006]

However, conventionally, in order to form a three-dimensional image or another three-dimensional image based on the above-described voxel operation, a dedicated ultrasonic probe for capturing three-dimensional data has been used. You need to use This ultrasonic probe includes, for example, an array transducer that is electronically scanned inside the probe, and a scanning mechanism that mechanically scans the array transducer in a direction orthogonal to a scanning plane. It is heavier and larger than an acoustic probe. Therefore, operability is reduced.

[0007] Conventionally, various ultrasonic probes are prepared according to each diagnosis site. Similarly, in order to form a three-dimensional ultrasonic image of each diagnostic site, it is necessary to prepare a dedicated ultrasonic probe for capturing three-dimensional data for each diagnostic site. However, this is disadvantageous in terms of cost. In other words, it is desired that three-dimensional ultrasonic diagnosis can be performed by using the existing ultrasonic probe as it is or by only slightly improving the existing ultrasonic probe.

By the way, a moving amount detector such as a roller is attached to an electronic scanning type ultrasonic probe, the position is measured at the time of manual scanning of the ultrasonic probe, and three-dimensional is obtained by using the measurement result. It is also possible to construct an image. But,
If the ultrasonic probe is not in good contact with the surface of the living body, the position cannot be detected with high accuracy. Therefore, without relying on such contact-type position detection,
It is desired to measure the motion (position and posture) of the ultrasonic probe without contact.

Further, if the scanning method of the ultrasonic probe is different, the operating conditions of the apparatus, especially the conditions of image processing, are correspondingly different. Is not provided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to enable a small and lightweight ultrasonic probe to capture three-dimensional echo data.

Another object of the present invention is to make it possible to capture three-dimensional echo data by using an existing ultrasonic probe as it is or by making a slight improvement thereto.

Another object of the present invention is to construct a three-dimensional image without requiring complicated coordinate calculations for each echo data.

It is another object of the present invention to specify a required scanning plane only by controlling the fetch timing.

Another object of the present invention is to realize a proper image processing by automatically recognizing a scanning method of manual scanning.

[0015]

[Means for Solving the Problems]

(1) In order to achieve the above object, the present invention provides a portable ultrasonic probe that forms a scanning surface by electronically scanning an ultrasonic beam, and movement of the ultrasonic probe by manual scanning. Motion measuring means for measuring the amount of movement, a timing signal generating means for sequentially generating a capture timing signal for each predetermined amount of movement of the ultrasonic probe, and using echo data of each scanning plane synchronized with the capture timing signal. And image processing means for forming an ultrasonic image obtained by imaging a three-dimensional region in the subject.

According to the above configuration, when the ultrasonic probe is manually scanned, the motion (parallel motion, rotational motion, etc.) of the ultrasonic probe is measured, and the fetch timing signal is sequentially determined based on the measurement result. Generated. Then, the echo data of the scanning plane specified by the capture timing signal is used in image processing. Here, the electronic scanning of the ultrasonic beam can be periodically and repeatedly executed. Even in such a case, only necessary data can be extracted in synchronization with the capture timing signal. Of course, the data may be captured by performing the electronic scanning once or several times at the time when the capture timing signal is generated.

As described above, since the echo data can be extracted for each scanning plane, the present invention is particularly advantageous when three-dimensional image processing is performed for each scanning plane.

[0018] In a preferred aspect of the present invention, the motion measuring means includes a magnetic field generator disposed near the subject, a magnetic field detector disposed on the ultrasonic probe, and a magnetic field detector. Computing means for computing the motion of the ultrasonic probe based on the output signal of the ultrasonic probe.

According to the above configuration, a steady magnetic field or a fluctuating magnetic field is formed around the subject, and the magnetic field is detected by the magnetic field detector arranged on the ultrasonic probe. Then, based on the detection result, the motion of the ultrasonic probe, that is, its three-dimensional position and orientation (posture) are calculated.
Since the magnetic field is used, it is not affected by the transmission and reception of ultrasonic waves by the ultrasonic probe. It is desirable to set and measure a plurality of magnetic fields having different directions according to the number of measurement dimensions of the movement. For example, when measuring three-dimensional coordinates and a rotation angle on each coordinate axis, for example, three magnetic field generating coils and three magnetic field detecting coils having different directions are used.

In order to detect a magnetic field with high accuracy, it is desirable to remove the magnetic members from the magnetic field generator and the magnetic field detector as much as possible. Note that, contrary to the above configuration, a magnetic field generator may be provided on the ultrasonic probe, and the magnetic field detector may be fixedly arranged. However, when comparing the magnetic field generator with the magnetic field detector, the magnetic field detector is generally smaller and lighter, and therefore it is desirable to provide it in the ultrasonic probe.

In a preferred aspect of the present invention, a detachable member for attaching and detaching the magnetic field detector to and from the ultrasonic probe is provided. As described above, if the magnetic field detector is detachable, the existing ultrasonic probe can be used as an ultrasonic probe for capturing three-dimensional data, and a dedicated probe is not required.

In a preferred aspect of the present invention, the magnetic field detector is built in the ultrasonic probe. Placing the magnetic field detector outside the ultrasonic probe may reduce the operability of the probe, but providing the magnetic field detector inside the probe can solve the problem . In this case, it is desirable that a part or the whole of the probe case is made of, for example, a non-magnetic material.

In a preferred aspect of the present invention, an appropriate range setting means for setting an appropriate range for the motion of the ultrasonic probe, and the image processing if the motion of the ultrasonic probe is out of the appropriate range. And processing restriction means for restricting

According to the above configuration, for example, when the ultrasonic probe is separated from the body surface or when the ultrasonic probe falls by mistake, execution of image processing can be limited. That is, as a result, the suitability of the manual scanning can be determined.

In a preferred aspect of the present invention, the proper range is set with respect to at least one of three-dimensional coordinates, a moving speed, a rotation angle, and a rotation angular speed of the ultrasonic probe. And

In a preferred aspect of the present invention, the apparatus further includes a scanning mode discriminating means for discriminating a scanning mode of the ultrasonic probe based on the motion measurement result, and the control corresponding to the scanning mode is performed. Features. If the scanning method can be automatically detected, for example, even if different scanning is performed between the first manual scanning and the second manual scanning, a complicated operation such as a change input of a scanning condition by a user is eliminated. In addition, appropriate image processing can always be expected.

[0027] In a preferred aspect of the present invention, the scanning method discriminating means discriminates between moving scanning and rotating scanning, and an ultrasonic image corresponding to each scanning method is formed.

(2) In the present invention, preferably, the image processing means sequentially executes a predetermined voxel operation on the echo data along each ultrasonic beam, so that each pixel of the ultrasonic image is formed. Voxel operation means for calculating pixel values is included.

[0029] In a preferred embodiment of the present invention, the voxel calculation means, and opacity calculating means for calculating the opacity alpha _i voxel i based on the echo data e _i, the transparency of the voxels i based on the echo data e _i beta and transparency calculating means for calculating a _i, a light emission amount calculating means for multiplying the opacity alpha _i in the echo data value e _i, calculates the light emission amount of the voxel i,
Multiplying the output light quantity of the previous voxel i-1 by the transparency β _i of the voxel i, and calculating the transmitted light quantity of the voxel i; adding the emitted light quantity and the transmitted light quantity;
And a light amount adding means for obtaining an output light amount of the voxel i, wherein the three-dimensional projection image is formed by making the output light amount of the end voxel correspond to a pixel value.

[0030] In a preferred aspect of the present invention, the voxel calculation means includes a voxel i based on the echo data ei.
Opacity calculating means for calculating the opacity α _i of the above, and the echo data e _i , the opacity α _i , and the input light amount C _INi corresponding to the output light amount of the previous voxel i−1, Output light amount calculating means for calculating the output light amount C _OUTi of the voxel i, wherein the three-dimensional projected image is formed by making the output light amount of the end voxel correspond to the pixel value.

According to the above configuration, the voxel processing using the opacity or the like is performed along the ultrasonic beam. As a result, the sequentially captured echo data can be sequentially processed in real time in real time,
The three-dimensional data memory required in the conventional device can be eliminated. That is, the captured echo data is processed in the capturing order, and data processing can be sufficiently performed without storing all the echo data in the three-dimensional data memory.

Incidentally, the opacity α _i relates to the degree of diffusion and scattering of ultrasonic waves to the surroundings of the voxel i, and the light emission amount indicates the intensity of the voxel i as a sound source (light source). Seem. On the other hand, the transparency β _i relates to the transmittance of ultrasonic waves, and the amount of transmitted light is considered to correspond to the transmittance when voxel i is viewed as a transmission medium. The light emission amount and the transmitted light amount are added to calculate the output light amount of the voxel i. Here, the output light amount indicates the degree of contribution of the voxel i to the pixel value. This output light amount is transferred to voxel processing (calculation of transmitted light amount) of the next voxel. Then, when the voxel processing reaches the final voxel, the output light amount of the final voxel is converted into a pixel value. Then, when each pixel value is obtained, one three-dimensional projection image is formed as a set of those pixel values.

It has been confirmed by experiments that this ultrasonic image has both the characteristics as a projection image and the characteristics as a stereoscopic image. That is, a tissue in a living body can be expressed in a transparent manner like an X-ray photograph, while it can be expressed with a sense of depth like an ultrasonic three-dimensional image. Therefore, for example, the surface and the inside of a fetus can be imaged by the same processing, and three-dimensional grasp of a tissue can be easily performed in disease diagnosis.

Of course, by changing the definitions of the opacity and the transparency, it is possible to construct an ultrasonic image having a desired image quality. For example, it is possible to enhance the transparency or the three-dimensional effect. Alternatively, the tissue surface can be enhanced or the interior of the tissue can be enhanced.

Such adjustment is performed by changing the definition of opacity and the like, and more specifically, can be performed by appropriately setting an end condition using opacity as a parameter. In this case, if the value of each opacity α _i to be sequentially added is large, the processing ends at a relatively early stage. For example, the image expression ends by seeing through the surface of the tissue. Conversely, if the value of each opacity α _i is small, the processing ends at a relatively late stage. For example, the image processing ends by seeing deep inside the tissue.

(3) In order to achieve the above object,
The present invention provides a portable ultrasonic probe, motion measuring means for measuring the motion of the ultrasonic probe by manual scanning, and scanning method discriminating means for discriminating a scanning method based on the measurement result of the motion. And a control unit that performs control based on the determined scanning method.

In a preferred aspect of the present invention, the control section includes:
A control for forming an ultrasonic image corresponding to a scanning method is performed.

[0038] In a preferred aspect of the present invention, the motion measuring means includes a magnetic field generator and a magnetic field detector, one of which is fixedly disposed near the subject, and the other of which is the ultrasonic probe. It is characterized by being arranged in a child.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the device configuration, the principle of image processing according to the embodiment will be described.

[Explanation of Image Forming Principle] The image processing method according to the present embodiment employs a well-known volume rendering method.
e Rendering) based on real-time image processing (especially ultrasonic image processing). At that time, special conditions are taken into account.

As shown in FIG. 1A, when an ultrasonic beam directed in the Y direction is scanned in the X direction, a scanning surface 10 is formed. When the scanning surface 10 is moved in the Z direction, a three-dimensional echo data capturing space 12 is formed as is well known. For this three-dimensional echo data capture space 12,
The voxel processing according to the present embodiment is performed along each ultrasonic beam, and the three-dimensional echo data capturing space 12 is projected on the projection plane 16 to obtain an ultrasonic image 100 shown in FIG.
It is. In the ultrasonic image 100, one line 100a in the X direction corresponds to one scanning plane 10. In other words,
One ultrasonic beam (perspective line) is one in the ultrasonic image 100.
Corresponds to a pixel.

Here, voxel processing, which will be described in detail below, is performed on the fetched echo data in chronological order, so that each echo data is temporarily stored in a three-dimensional echo data memory to form an image. It is not necessary to read the echo data in the order necessary for the data processing, and the data processing synchronized with the data acquisition can be performed.

FIGS. 2 and 3 show the concept of the voxel 20. FIG. One voxel converts the received signal to A
It corresponds to one echo data obtained by the / D conversion, in other words, it corresponds to a volume (sample point) corresponding to one cycle of the A / D conversion rate. That is,
An ultrasound beam is assumed as a collection of many voxels. FIG. 2 shows each voxel from i-1 to _LLAST . The value obtained by performing the processing sequentially from the first voxel is the luminance value P (x, 1) of one pixel constituting the ultrasonic image.
y).

Here, opacity α and transparency β [β = (1−α) in this embodiment] are defined for each voxel. The opacity α corresponds to spontaneous light emission around the voxel as shown in FIG. The transparency (1−α) corresponds to the degree of transmission of light from the previous voxel in the voxel. The opacity α is set in a range of 0 ≦ α ≦ 1, and in the present embodiment, the opacity is defined as a function of the echo data (echo value). Specifically, for example,

Α = k1 · e ^k2 (1) Here, e is the value of the echo data, and k1 is a coefficient (parameter), which is variably set by the user. A numerical value larger than 1 is desirably substituted for k2, for example, k2 = 2 or 3. That is, α changes nonlinearly with respect to the value e of the echo data.

As shown in FIG. 2, for a certain voxel i, an input light amount C _INi and an output light amount C _{OU Ti} are defined, and the input light amount C _INi is the output light amount C _IN of the _immediately preceding voxel i-1. Equivalent to _{OU Ti-1} . That is,

## EQU2 ## There is a relationship of C _INi = C _OUTi-1 (2). However, C _{IN i} = 0 at the start voxel at which the voxel processing is started. Note that the start voxel is set automatically or artificially.

For each voxel, a light emission amount and a transmission light amount are defined based on the opacity α and the transparency (1−α). That is, the light emission amount of voxel i is defined as the product of the opacity and the echo data, and is α _i · e _i . The transmitted light amount of voxel i is defined as the product of the transparency and the input light amount, and is (1−α _i ) · C _INi .

In this embodiment, as shown in FIG.
The light emission amount and the transmitted light amount are added as follows, and the output light amount C _{OUTi of the} voxel is determined.

[0048]

C _OUTi = (1−α _i ) · C _INi + α _i · e _i (3) where C _INi = C _{OUTi−1 according} to the above second equation. That is, the calculation result of the previous voxel is used for calculation of the next voxel.

While the above equation (3) is sequentially performed from the start voxel to the next voxel and then to the next voxel, the opacity α _i of each voxel is added, and the added value Σα _i becomes 1 At the time when the processing has reached (end condition). However, even when the processing is the last (or the set depth) voxel L _LAST , the processing is terminated (forced termination condition). That is, the conditions under which the processing ends are as follows:

４α _i = 1 or i = L _LAST (4) The termination of the process when Σα _i = 1 means that the process is stopped when the sum of the opacity reaches 1.
Of course, the condition of the fourth expression, in particular, the maximum addition value (end determination value) of α _i may be changed according to the condition.

The output light-amount C _{OU T} of [0050] or more voxels at the time the end determination is made (final voxel) is brightness P (x, y) of the corresponding pixel is used as a. Then, when such pixel value calculation for each ultrasonic beam is performed for all ultrasonic beams, pixel values of all pixels constituting the ultrasonic image can be obtained. That is, one ultrasonic image is formed.

As shown by the above equation (3), the luminance value P of the pixel
(X, y) reflects the values of all echo data from the start voxel to the end voxel. But,
It reflects both scattering and absorption of ultrasonic waves at each voxel, not just simple integration as in the past. Therefore, an ultrasonic image having both the depth (three-dimensional) and transparent properties, such as an image formed by light transmitted from a light source and scattered and absorbed by each voxel, is obtained. Can be configured.

In the above formula (3), the transparency is defined by (1−α _i ), that is, the transparency can be represented by the opacity α _i , so the concept of transparency is apparently deleted from the arithmetic expression. be able to. Therefore, the output light amount C _OUTi can be calculated based on the same principle by _modifying the third expression as follows.

[0053]

C _OUTi = (1−α _i ) · C _INi + α _i · e _i (3) = C _INi + α _i · (e _i −C _INi ) (5-1) = C _INi + Δ _i ··· (5-2) (where Δ _i = α _i · (e _i −C _INi )) The above equation 5-1 is obtained by rewriting the third equation, and the second term is replaced with Δ _i. , 5-2. That is, the output light amount C _OUTi of voxel i is _equal to the input light amount C _OUTi.
It is defined as the sum of the corrected amount delta _i in _INi.
As is clear from the above equation transformation process, the concept of transparency (1−α _i ) is also included in this equation 5-2, and there is no difference in principle.

[Preferred Embodiment] FIG. 5 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 5 is a block diagram showing the overall configuration of the ultrasonic diagnostic apparatus.

The ultrasonic probe 30 is, for example, an ultrasonic probe used in contact with the body surface. Of course, the present invention can be applied to, for example, an ultrasonic probe inserted into a body cavity. The ultrasonic probe 30 has a built-in array transducer in which a plurality of transducers are aligned. The array transducer is electronically scanned under the control of the ultrasound transmission / reception unit 44, whereby the ultrasound beam is scanned to form a scanning surface. This is similar to a conventional ultrasonic probe.
The ultrasonic probe 30 is connected to the apparatus main body by a probe cable (not shown).

In the ultrasonic diagnostic apparatus according to the present embodiment,
A motion measuring unit 32 for measuring the position and posture of the ultrasonic probe 30 is provided. In the present embodiment, the motion measuring unit 32 includes a magnetic field generating unit 34, a magnetic field detecting unit 36 for detecting a generated magnetic field, and a motion detecting unit 38 for calculating motion information based on the detection result. Is what is done. In addition, as the magnetic field generation unit 34, the magnetic field detection unit 36, and the motion detection unit 38 illustrated in FIG. 5, known ones can be used. The magnetic field generator 34 is arranged, for example, on a bed or the like on which a subject is placed.
And three magnetic field generating coils for generating a magnetic field in each direction. The magnetic field generator 34 is supplied with a predetermined magnetic field generation drive signal from the motion detector 38. A fluctuating magnetic field having components in each direction is formed by the magnetic field generator 34.

The magnetic field detecting section 36 is formed of, for example, a cube having a side of about 1 cm, and detects a magnetic field generated by the magnetic field generating section 34. Magnetic field detector 36
Includes, for example, three mutually orthogonal magnetic field detecting coils for detecting magnetic fields in each direction. The detection signal detected by each coil is output to the motion detection unit 38. In the present embodiment, the magnetic field detector 36 is detachably attached to the ultrasonic probe 30. For example,
The magnetic field detecting unit 36 is attached by a mounting belt described later.
Is mounted on the ultrasonic probe 30. Of course, as described later, the magnetic field generator 34 may be built in the ultrasonic probe 30.

When the magnetic field generator 34 and the magnetic field detector 36 are compared in terms of form, the magnetic field detector 36 is generally much smaller. Therefore, in the present embodiment, the magnetic field detection unit 36 is provided in the ultrasonic probe 30. However, the magnetic field generator 34 may be attached to the ultrasonic probe 30 while the magnetic field detector 36 may be fixedly arranged on, for example, a bed.
In principle, even with such a configuration, the ultrasonic probe 30
Motion can be detected.

FIG. 6 shows a specific example of the arrangement of the magnetic field generator 34 and the magnetic field detector 36. In FIG. 6, a subject 200 is placed on a bed 201.
A magnetic field generator 34 is fixedly arranged below the bed 201. Thus, a magnetic field 202 is formed. Incidentally, the magnetic field 202 is a stationary magnetic field or a fluctuating magnetic field.

The magnetic field detector 36 is mounted on the ultrasonic probe 30 by the mounting belt 64. Specifically, the magnetic field detecting unit 36 is fixed to the mounting belt 64, and by attaching the mounting belt 64 to the ultrasonic probe 30, as a result, the magnetic field detecting unit 36 is mounted on the ultrasonic probe 30. You. According to such a mounting belt 64, there is an advantage that the magnetic field detecting unit 36 can be mounted on the ultrasonic probes 30 of various sizes. Of course, the magnetic field detection unit 36 may be attached to the ultrasonic probe 30 using, for example, a double-sided tape or an engagement mechanism.

The signal line 62 extending from the magnetic field detecting section 36 is led to the apparatus main body together with the cable 60 coming out of the ultrasonic probe 30, for example. In this case, it is desirable to perform clipping at predetermined intervals in order to integrate the cable 60 and the signal line 62.

In the measurement environment as shown in FIG. 6, when performing an ultrasonic diagnosis of, for example, the abdomen of the subject 200,
The ultrasonic probe 30 is gripped by the operator, and in this state, the ultrasonic probe 30 is manually operated in a direction perpendicular to a scanning plane formed by the ultrasonic probe 30, for example, in a manual scanning direction 204. It is moved and scanned. Thus, a three-dimensional data acquisition space can be constructed in the subject 200.

In the example shown in FIG. 6, the magnetic field generator 34
Is fixed to the back side of the bed 201, but may not necessarily be fixed to the bed 201, but may be provided, for example, on the side of the subject on the bed or on a wall near the subject.

Returning to FIG. 5, the ultrasonic transmission / reception section 44 supplies a transmission signal to the ultrasonic probe 30 in the same manner as in the related art, and performs a predetermined operation on the reception signal from the ultrasonic probe 30. This executes signal processing. The ultrasonic transmission / reception unit 44 controls the electronic scanning of the ultrasonic beam. The received signal (echo data) output from the ultrasonic transmission / reception unit 44 is output to the next data selection unit 46.

The motion detecting section 38 in the motion measuring section 32
Are the three-dimensional coordinates X, Y, Z of the ultrasonic probe 30 and the rotation angles θ _X , θ _Y , θ of the ultrasonic probe 30 on each coordinate axis based on the output signal from the magnetic field detection unit 36. Outputs _Z. Incidentally, if the manual scanning is always performed by the parallel movement, the information on the rotation angle is not necessarily required. Also,
If the ultrasonic probe 30 moves substantially within the XY plane, information in the Z direction is not required.

The timing control unit 40 includes a motion detection unit 38
Is to determine the timing for specifying the scan plane from which the echo data is to be acquired, based on the various types of motion information output from. The specific configuration is shown in FIG. 7, which will be described later in detail.

The pulse generator 42 is provided with the timing controller 4
A synchronization pulse (data capture signal) 206 having a predetermined level is output based on a timing signal output from 0. The synchronization pulse 206 is output to the data selection unit 46 and the image construction unit 52 described later.

The data selecting section 46 has a function of selecting and outputting only the echo data of the specified scanning plane at the timing when the synchronization pulse 206 is obtained. That is, in the present embodiment, electronic scanning of the ultrasonic beam is always performed in the ultrasonic probe 30 under the control of the ultrasonic transmitting / receiving unit 44, and as a result, some echo data is always output from the ultrasonic transmitting / receiving unit 44. However, the data selection unit 46 extracts only necessary echo data in the scanning plane from such data. This makes it possible to extract echo data for each scanning plane. Note that the synchronization pulse 206 may be given to the ultrasonic transmission / reception unit 44 so that electronic scanning is performed at that timing to capture echo data. In this case, the output of the synchronization pulse itself corresponds to the selection of the echo data.

The three-dimensional projected image forming section 48 includes a voxel calculating section 50 and an image forming section 52.
Image processing principle described above (especially, equations (3) and (4))
Is used to form a three-dimensional projected image. The voxel operation unit 50 executes the above-described voxel operation for each piece of echo data along the ultrasonic beam, and determines a pixel value of a pixel corresponding to the ultrasonic beam. The opacity parameter used in the voxel operation is
It is set by the opacity setting unit 56. The range of the voxel calculation, that is, the calculation end point, is set by the calculation range setting unit 54. The pixel values corresponding to each ultrasonic beam output from the voxel operation unit 50 are sent to the image forming unit 52, where a three-dimensional projected image for one screen is formed. At the same time, the brightness of each pixel value is converted and output as image data to the display unit 58.

As shown in FIG. 1, in the image processing according to the present embodiment, one line of image data is formed for one scanning plane. In other words, the image processing is executed in units of scanning planes. Have been. Correspondingly, the data selection unit 4
In step 6, echo data is extracted for each scanning plane in synchronization with the synchronization pulse.

Therefore, according to the present embodiment, the complicated processing of storing all the echo data once in the three-dimensional echo data memory and reconstructing the data while taking the three-dimensional coordinates into consideration as in the prior art is not required. It is unnecessary, and only necessary data can be sequentially processed in the chronological order.
In the case where the manual scanning is performed quickly, one stereoscopic projection image is formed as a result as a result,
If the manual scanning is slow, one stereoscopic projected image will be formed at a speed corresponding to the slow manual scanning.

Next, a specific configuration of the timing control unit will be described with reference to FIG.

In FIG. 7, the exercise information input section 70 receives the respective exercise information output from the exercise detection section 38 shown in FIG. If the operation of resetting the origin is performed immediately before the manual scanning of the ultrasonic probe is started, the position and orientation of the ultrasonic probe 30 at that time are set as the origin. As a result, the origin of a virtual scale described later is also determined. The motion information of the ultrasonic probe 30 after the origin is reset is output after being divided into movement information and rotation information.
Here, the movement information is the X coordinate, the Y coordinate, and the Z coordinate, and the rotation information is the angle information of θ _X , θ _Y , and θ _Z.

The processing restricting section 72 executes control for interrupting the image processing when each exercise information does not fall within the proper range set by the proper range setting section 74. For example, when the ultrasonic probe falls from the hand or when the operator separates the ultrasonic probe from the subject, the echo data in that state is excluded from the image processing in order to eliminate such echo data. There are restrictions on image processing. Here, the exercise information to be managed includes, for example, a moving speed, a rotational angular speed, and the like, in addition to the input information (three-dimensional coordinates, rotation angle). By controlling the speed, an alarm can be issued to the operator when, for example, manual scanning is extremely fast and image processing cannot be performed properly. Therefore, in the processing restriction unit 72,
If it is determined that the value is outside the appropriate range, an alarm is output to a control unit (not shown).

If the processing limiter 72 determines that the movement is within the appropriate range, the movement information and the rotation information output from the movement information input unit 70 are output to the scanning method determination unit 76. In the present embodiment, the scanning method determination unit 76 determines whether the manual scanning is a moving scan (parallel movement scanning) or a rotational scanning. In particular,
The difference between the current value and the previous value is calculated for each piece of exercise information, and the scanning method is determined by referring to the difference value. For example, when the difference value is large with respect to the movement information, it is determined that the scan is a parallel movement scan. When the difference value is large with respect to the rotation information, it is determined that the scan is a rotation scan. In this case, if a composite scan in which the rotational movement is performed while performing the parallel movement is performed, an error signal may be output to a control unit (not shown) because an appropriate image may not be constructed. . In the present embodiment, the scanning method is determined using the difference of the motion information. However, the scanning method may be determined by, for example, calculating an integrated value or a three-dimensional vector.

When the scanning method determining section 76 determines that the scanning is the parallel movement scanning, the movement information is sent to the movement vector calculating section 80. The movement vector calculation unit 80 calculates a movement direction vector V _XYZ relating to the movement of the ultrasonic probe by calculating the difference between the current three-dimensional coordinate value and the immediately preceding three-dimensional coordinate value. However, in the present embodiment, the calculation of this vector is executed only between two pieces of motion information obtained first after the origin is reset, and thereafter, the calculation of the movement direction vector is omitted. Of course, the moving direction vector may always be calculated, and the calculation result may be used for image processing.

When the moving direction vector V _XYZ is obtained as described above, a virtual scale 210 is assumed in a three-dimensional space as shown in FIG. That is, the direction of the virtual scale 210 is oriented in the direction of the movement direction vector, and the origin of the virtual scale 210 is the position of the ultrasonic probe at the time when the origin is reset.

The interval setting section 84 sets the output interval of the timing signal based on the transmission / reception conditions.
Conceptually, the interval of the scale in the virtual scale 210 is set. Here, the scale corresponds to the output position of the timing signal.

The moving position comparing section 82 includes a scanning mode determining section 7
6, the current position of the ultrasonic probe is compared with the scale assigned on the virtual scale 210, and the ultrasonic probe matches the scale or the scale. , The timing generator 86
Is given an instruction to generate a timing signal. When the generation instruction is input, the timing generator 86 outputs a timing signal to the pulse generator 42 shown in FIG.

Therefore, regardless of the moving speed of the ultrasonic probe 30, the synchronization pulse 206 is generated every time the ultrasonic probe 30 moves at a constant interval from the origin, and the synchronization pulse 206 is generated. The echo data in the scanning plane, which is taken in synchronism with the output of, is sequentially image-processed.

In FIG. 7, when the scanning method determination section 76 determines that the scanning is the rotation scanning, the rotation vector calculation section 88 calculates the rotation direction vector Vθ _XYZ based on the rotation information. In the present embodiment, the calculation of the rotation direction vector is performed only once after the origin is reset. However, the calculation of the rotation direction vector may be always performed thereafter.

Based on the rotation direction vector calculated in this way, as shown in FIG.
2 can be assumed. The interval setting section 92 allocates the scales on the circular scale 212 shown in FIG. 9 based on the transmission and reception conditions. When the current rotation angle of the ultrasonic probe 30 matches the scale on the virtual scale 212 or passes through the scale, the rotation angle comparison unit 90 compares the rotation angle with the timing generation unit 86. The generation instruction is output from the unit 90. As a result, a timing signal is output from the timing generator 86 to the pulse generator 42. Note that the rotation vector calculation unit 88 calculates the rotation direction vector by calculating the difference between the current rotation information and the immediately preceding rotation information.

FIG. 10 shows the relationship between the moving scan of the ultrasonic probe 30 and the ultrasonic image formed thereby. Each time the ultrasonic probe 30 passes through the scale on the virtual scale 210, echo data is fetched for each scanning plane, and in synchronization with this, processing of image data is performed for each scanning plane. Specifically, an image 10A for one line is constituted for one scanning plane. Therefore, by performing the moving scanning operation over a predetermined range, one ultrasonic image, that is, a three-dimensional projected image can be formed. The virtual scale 210 in the moving scan corresponds to coordinates in a predetermined direction in the ultrasonic image, and if the scale on the virtual scale is made finer, the pixel density in the direction in the ultrasonic image is also improved. If necessary, interpolation or averaging between image data may be executed.

FIG. 10 shows the processing in the case where the ultrasonic probe 30 is scanned in parallel. However, the same processing as described above is executed also in the case where the ultrasonic probe is rotated and scanned. You. That is, each time the ultrasonic probe 30 rotates by a predetermined angle, an image of one line in a predetermined direction in the ultrasonic image is formed. That is, radial scanning is performed.

Next, another embodiment will be described.

In the above embodiment, the synchronization pulse is generated by making the virtual scale coincide with the moving direction of the ultrasonic probe 30. For example, as shown in FIG. Two orthogonal virtual scales, that is, a main axis virtual scale 300 and a sub axis virtual scale 302 may be set in a plane including the direction vector, and image processing may be performed using these virtual scales. In this case, for example, every time the ultrasonic probe 30 crosses the scale of the virtual spindle scale 300, a spindle synchronization pulse 304 is generated, and the spindle synchronization pulse 304 is output to the data selector 46 shown in FIG. At the same time, each time the ultrasonic probe 30 crosses the scale on the sub-axis virtual scale 302, a sub-axis synchronization pulse 306 is generated, and the pulse is used as the coordinates of the ultrasonic probe 30 in the direction of the sub-axis virtual scale 302. Component 5
2 may be output.

FIG. 12 shows such a process. When the ultrasonic probe 30 is moved in parallel in an oblique direction,
One line of the image 10A corresponding to the scanning surface is sequentially displayed in an oblique direction. That is, an image is constructed with the same image as the oblique scanning.

In the above-described embodiment, the ultrasonic probe 30
Although the magnetic field detecting unit 36 is mounted on the outer surface of the ultrasonic probe 400, the magnetic field detecting unit 36 may be installed inside the main body case 402 of the ultrasonic probe 400, for example, as shown in FIG. An array vibrator 406 composed of a plurality of vibrating elements is built in the probe body case 402, and a cable group 406A extending from each vibrating element is a probe cable 404.
Is drawn into. Similarly, the magnetic field detector 36
It is desirable that the signal line group 36A extending from the probe cable 404 also be drawn into the probe cable 404.

According to the above-described embodiment, there is an advantage that three-dimensional echo data can be easily taken in using an existing ultrasonic probe or the like without impairing the advantage of the voxel operation.

[0090]

As described above, according to the present invention, three-dimensional echo data can be acquired by using an existing ultrasonic probe as it is or by making a slight improvement thereto. Further, a three-dimensional image can be constructed without requiring a complicated coordinate operation for each echo data.
Further, a necessary scanning plane can be specified only by controlling the acquisition timing. Further, it is possible to automatically recognize the scanning method of the manual scanning and realize appropriate image processing.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a three-dimensional data acquisition space and a projected image.

FIG. 2 is a diagram illustrating a relationship between an input light amount and an output light amount of each voxel.

FIG. 3 is a diagram showing a light emission amount of each voxel.

FIG. 4 is a diagram for explaining an output light amount of a voxel.

FIG. 5 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 6 is a schematic diagram showing a specific example of a magnetic field generation unit and a magnetic field detection unit.

FIG. 7 is a block diagram illustrating a specific configuration of a timing control unit.

FIG. 8 is a diagram illustrating a relationship between a virtual scale of a straight line and a synchronization pulse.

FIG. 9 is a diagram illustrating a relationship between a circular virtual scale and a synchronization pulse.

FIG. 10 is a diagram showing image formation by parallel movement scanning.

FIG. 11 is a diagram showing two orthogonal virtual scales.

FIG. 12 is a diagram illustrating image formation using two orthogonal virtual scales.

FIG. 13 is a diagram showing another embodiment of the ultrasonic probe.

[Explanation of symbols]

30 ultrasonic probe, 32 motion measuring section, 34 magnetic field generating section, 36 magnetic field detecting section, 38 motion detecting section, 40 timing control section, 42 pulse generating section, 46 data selecting section, 48 stereoscopic projection image forming section, 50 Voxel operation unit, 52 Image composition unit.

Claims (14)

[Claims] 1. A portable ultrasonic probe that forms a scanning surface by electronically scanning an ultrasonic beam, a motion measuring unit that measures the motion of the ultrasonic probe by manual scanning, For each predetermined momentum of the acoustic probe, a timing signal generating means for sequentially generating a capture timing signal, and using echo data of each scanning plane synchronized with the capture timing signal, an image of a three-dimensional region in the subject is formed. An ultrasonic diagnostic apparatus, comprising: image processing means for forming a converted ultrasonic image. 2. The apparatus according to claim 1, wherein the motion measuring means includes: a magnetic field generator arranged near a subject; a magnetic field detector arranged on the ultrasonic probe; Calculating means for calculating the motion of the ultrasonic probe based on an output signal from a detector. 3. The ultrasonic diagnostic apparatus according to claim 2, further comprising an attaching / detaching member for attaching / detaching the magnetic field detector to / from the ultrasonic probe. 4. The ultrasonic diagnostic apparatus according to claim 2, wherein the magnetic field detector is built in the ultrasonic probe. 5. The apparatus according to claim 1, wherein an appropriate range setting means for setting an appropriate range for the motion of the ultrasonic probe, and wherein the motion of the ultrasonic probe is out of the appropriate range. An ultrasonic diagnostic apparatus comprising: processing restriction means for restricting image processing. 6. The apparatus according to claim 5, wherein the appropriate range is set with respect to at least one piece of motion information among three-dimensional coordinates, a moving speed, a rotation angle, and a rotation angular speed of the ultrasonic probe. An ultrasonic diagnostic apparatus characterized by the above-mentioned. 7. The apparatus according to claim 1, further comprising: a scanning mode determination unit configured to determine a scanning mode of the ultrasonic probe based on the motion measurement result, wherein control corresponding to the scanning mode is performed. An ultrasonic diagnostic apparatus characterized by the above-mentioned. 8. An ultrasonic apparatus according to claim 7, wherein said scanning method discriminating means discriminates between moving scanning and rotating scanning, and an ultrasonic image corresponding to each of said scanning methods is formed. Diagnostic device. 9. The apparatus according to claim 1, wherein the image processing unit sequentially executes a predetermined voxel operation on echo data along each ultrasonic beam, thereby obtaining a pixel of each of the pixels constituting the ultrasonic image. An ultrasonic diagnostic apparatus including a voxel calculating means for calculating a pixel value. 10. A device according to claim 9, wherein the voxel calculation means, and opacity calculating means for calculating the opacity alpha _i voxel i based on the echo data e _i, of the voxel i based on the echo data e _i Means for calculating transparency β _i , and multiplying echo data e _i by opacity α _i to obtain voxel i
A light emission amount calculating means for calculating the light emission amount of the voxel i; a transmission light amount calculation means for calculating the transmitted light amount of the voxel i by multiplying the output light amount of the previous voxel i-1 by the transparency β _i of the voxel i A light amount adding means for adding the amount of light and the amount of transmitted light to obtain the amount of light output from the voxel i, and forming the ultrasonic image in such a manner that the amount of light output from the end voxel corresponds to the pixel value. Ultrasound diagnostic device. 11. The apparatus of claim 9, wherein the voxel calculation means, and opacity calculating means for calculating the opacity alpha _i voxel i based on the echo data e _i, the echo data e _i, the opacity α _i and the input light intensity C _INi corresponding to the output light intensity of the previous voxel i-1
And an output light amount calculating means for calculating the output light amount C _OUTi of the voxel i based on the ultrasonic diagnostic image, wherein the ultrasonic light image is formed in such a manner that the output light amount of the end voxel corresponds to the pixel value. apparatus. 12. A portable ultrasonic probe, motion measuring means for measuring motion of the ultrasonic probe by manual scanning, and scanning method discrimination for discriminating a scanning method based on a result of the measurement of the motion. An ultrasonic diagnostic apparatus comprising: a control unit that performs control based on the determined scanning method. 13. The ultrasonic diagnostic apparatus according to claim 12, wherein the control unit executes control for forming an ultrasonic image corresponding to a scanning method. 14. The apparatus according to claim 12, wherein the motion measuring means includes a magnetic field generator and a magnetic field detector, one of which is fixedly disposed near the subject, and the other of which is the magnetic field generator. An ultrasonic diagnostic apparatus which is arranged on an ultrasonic probe.