JP3081664B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to an ultrasonic diagnostic apparatus having an improved digital scan converter.

2. Description of the Related Art An ultrasonic probe transmits an ultrasonic pulse from a living body into a living body, and receives echoes of the ultrasonic pulse reflected from the living body by the same or separately provided ultrasonic probe.
2. Description of the Related Art There have been conventionally devised various ultrasonic diagnostic apparatuses capable of displaying, as a visible image, information collected from a plurality of directions in a living body by transmitting and receiving while shifting the direction of an ultrasonic pulse.

[0003] Among such ultrasonic diagnostic apparatuses, there is a sector scanning type in which a fan-shaped area is scanned with respect to the ultrasonic probe 1 as shown in FIG. There is an apparatus that performs ultrasonic scanning in polar coordinates, such as a radial sector scanning type that scans a circular area. Such an ultrasonic diagnostic apparatus has an advantage that a wide field of view can be realized with a small probe. In particular, in an intra-body cavity scanning type device such as an ultrasonic endoscope, a radial sector scanning type is often used because scanning can be performed over the entire circumference of a lumen.

In an ultrasonic diagnostic apparatus, as a display device for displaying an ultrasonic image, a television monitor for displaying an image by scanning in a rectangular coordinate system as shown in FIG. 9 is generally used. Even in the apparatus for scanning the ultrasonic waves in the polar coordinates as described above, the apparatus has means for converting the ultrasonic waves in the polar coordinates into the television scans in the rectangular coordinates, and displays the ultrasonic image on the television monitor. I have. This is because if the scanning method is converted into television scanning, it is possible to display on the same display device even if a plurality of ultrasonic probes having different ultrasonic scanning methods are switched and used. This is because various types of developed inexpensive and high-performance hard copy devices (for example, video printers) and auxiliary storage devices (for example, VTRs) can be used.

[0005] In order to display an image obtained by ultrasonic scanning in polar coordinates on a television monitor, it is necessary to convert the image into rectangular coordinates. Means for converting the scanning method such as the polar coordinate scanning into the orthogonal coordinate scanning is called a scan converter. As such a scan converter, a digital scan converter (DSC) is generally used today.

[0006] The DSC converts an ultrasonic echo signal (analog signal) into a digital signal and outputs the digital signal to a television display 1.
The image data is temporarily written in an image memory made up of a digital memory having a storage capacity corresponding to a screen in accordance with an ultrasonic scanning method and read out in accordance with a television scanning method.

[0007] By using such a DSC, it is possible to display an image subjected to ultrasonic scanning in polar coordinates on a television monitor. However, as shown in FIG. 10, ultrasonic scanning lines a and b scanned in polar coordinates are used. Becomes wider as the distance from the probe increases, so that an address where no image signal data is written (blank portion) occurs in the image memory.

[0008] Therefore, interpolation is required to fill addresses where no image signal data is written. For this reason, for example, Japanese Patent Publication No. 2-28870 discloses a conventional example in which interpolation is performed by writing in an image memory as shown in FIGS. The ultrasonic probe 1 emits an ultrasonic wave to the subject in response to a transmission pulse from the transmitting / receiving circuit 2, and receives a reflected ultrasonic signal reflected at a discontinuous portion of the acoustic impedance of the subject and outputs the signal to the transmitting / receiving circuit 2. The transmitting / receiving circuit 2 outputs an ultrasonic echo to the A / D converter 3.

The digital signal converted by the A / D converter 3 is input to an interpolation processing unit 4, where the digital signal is subjected to interpolation processing and written into an image memory 5. The data written in the image memory 5 is input to a D / A converter 6 and converted into an analog signal.
It is output to the television monitor 7 and a tomographic image is displayed. Each circuit is controlled by the system controller 8.

The interpolation processing section 4 has the configuration shown in FIG. A digital signal converted by the A / D converter 3,
That is, a series of data corresponding to each deflection angle in three sector scans is stored in the three buffer memories 12, 13, and 14 via the demultiplexer 11. The contents of the buffer memories 12, 13, and 14 are read out at twice the speed of writing, and are stored in the first selector 15 and the averaging unit 1.
6 is input. The first selector 15 selects one of the buffer memories 12, 13, and 14 under the control of the controller 18, and the averaging unit 16 controls the buffer memories 12, 1, and 1 under the control of the controller 18.
Any one of the two output data items 3 and 14 is selected, and the average value is calculated. The outputs of the first selector 15 and the averaging unit 16 are output to the image memory 5 via the second selector 17.

FIGS. 13 and 14 show Japanese Patent Publication No. 2-28.
No. 871, in which interpolation is performed by reading an image memory. In this conventional example, when a pixel having no data is detected when data is read out from an image memory in synchronization with a horizontal scan of a television scan, two adjacent pixels on the same horizontal scan line are averaged and filled. It is.

In the configuration of FIG. 13, an image memory 5 is interposed in front of the interpolation processing section 4 in FIG. 11, and data (sector pattern) in which no image data is stored from the sector pattern memory 9 is stored in the interpolation processing section 4. ) Is entered. The configuration of the interpolation processing unit 4 in this conventional example is as shown in FIG. The data in the image memory 5 is input to the latch (1) 21 and also to the averaging unit 23. The output β of the latch (1) 21 is input to the latch (2) 22 and also to the selector 24. The output α of the latch (2) 22
And the averaging value of the averaging unit 23 is supplied to the selector 2
4 to the D / A converter 6 .

[0013]

[Problems to be Solved by the Invention]
In the circuit configuration described in Japanese Patent Application Laid-Open Publication No. H10-76, in which interpolation is performed by writing in the image memory 5, the interpolation processing unit 4 is provided at a stage preceding the image memory 5. In such an interpolation processing unit 4, FIG.
Requires three buffer memories 12, 13, and 14 (to read data from two buffer memories and write the data coming from the receiving circuit into one remaining buffer memory while performing interpolation). Therefore, there is a problem that the circuit scale becomes large and the circuit configuration becomes complicated.

In the circuit configuration described in Japanese Patent Publication No. 2-28871, the image data is read out from the image memory 5 in accordance with the television scanning, pixels having no data are detected, and pixels on both sides on the same horizontal scanning line are detected. There is a problem that the accuracy of interpolation is not good because interpolation is not necessarily performed between pixels closest to the pixel to be interpolated because the data is merely averaged and the pixel is filled to fill the pixel. .

The present invention has been made in view of the above points, and does not require a temporary storage means such as a buffer memory in addition to an image memory, can realize a small-scale DSC circuit, can be realized at low cost, and has high precision. It is an object to provide an ultrasonic diagnostic apparatus capable of performing interpolation.

[0016]

SUMMARY OF THE INVENTION Ultrasound diagnosis according to the present invention
Device includes a scanning means for scanning the ultrasonic wave polar, said
Receiving means for receiving the ultrasonic wave scanned by the scanning means
And writing the ultrasonic scanning line received by the receiving means.
Based on the control signal, first and second image memory, the first, second image memo to be stored as pixel information on the polar coordinates
The ultrasonic scanning lines are stored alternately for every other line.
So that the write control signal is transmitted to the first and second images.
And writing control means for alternately outputting to the memory, before
The polar coordinates stored in the first and second image memories
A specific pixel in the area specified by the pixel information is directly
An instructing means for instructing by the intersection coordinates and the first image memory;
Of the stored pixel information on the polar coordinates,
The first pixel information closest to the pixel indicated by the column is
Reading from the first image memory;
Of the pixel information on polar coordinates stored in the image memory,
A second image closest to the pixel specified by the specifying means;
Reading means for reading elementary information from the second image memory
And the reading means stores the first and second image memories.
Based on the first and second pixel information read from each,
Creating information on the pixel specified by the specifying means;
Pixel information creating means .

[0017]

The pixel of the scanning line scanned by the polar coordinate is stored in two memories.
And the scanning lines stored in the memory
A specific pixel in the area specified by
To the two memories closest to the indicated pixel.
Pixel information on the scanning line stored in polar coordinates is
Each of which is read, and based on the two read pixel information,
Then, information of the pixel designated by the rectangular coordinates is created .

With such a configuration, the nearest pixels on the ultrasonic scanning line sandwiching a pixel to be interpolated are simultaneously read out without the need for temporary storage means such as a buffer memory other than the image memory. Weighted and interpolated.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. 1 and 2 relate to a first embodiment of the present invention. FIG. 1 shows a configuration of a signal processing system of the ultrasonic diagnostic apparatus of the first embodiment, and FIG. 2 shows a configuration of an interpolation processing unit.

In the first embodiment, every other ultrasonic scanning line is written in two divided image memories (even-numbered ultrasonic scanning lines are written in one image memory, and odd-numbered ultrasonic scanning lines are written in the other image memory). Are written alternately, and a total of two data (data of adjacent ultrasonic scanning lines) are read simultaneously from each of the two image memories, and are interpolated.

The ultrasonic probe 31 shown in FIG. 1 is attached to a shaft which is driven to rotate by a motor (not shown), and the ultrasonic probe 31 is applied to a subject in a body by a mechanical radial scan or a linear scan together with the mechanical radial. The axis direction (longitudinal direction) of the probe 31 while gradually shifting the angle or together with the angle
The ultrasonic wave is emitted while shifting slightly. The transmission / reception circuit 32 applies an electric pulse to the ultrasonic probe 31,
Ultrasonic waves are emitted from the ultrasonic probe 31 toward the inside of the body, and an echo of the ultrasonic wave received by the ultrasonic probe 31 is amplified and detected.

A series of reflected wave signals taken out from the transmission / reception circuit 32 are sequentially sampled at a constant cycle by the A / D converter 33 and digitized. The signal data digitized by the A / D converter 33 is alternately written to the image memories 34 and 35 every other ultrasonic scanning line. Writing of signal data to each of the image memories 34 and 35 is sequentially performed according to an address signal generated by a write address generation circuit 36.

The read address generating circuit 37 generates a read address of the image memory according to the television scanning system. The read address is converted into polar coordinates by a coordinate conversion circuit 38 composed of a ROM in which the coordinate conversion table is written, and is given to the image memories 34 and 35. The data read from the image memories 34 and 35 is input to the interpolation processing unit 39. The data read from the image memories 34 and 35 by the interpolation processing unit 39 are respectively weighted and added. The data interpolated by the interpolation processing unit 39 is converted into an analog signal by the D / A converter 41 and displayed on the display device 42.

When the ultrasonic probe 31 is a mechanical radial scan, a two-dimensional ultrasonic tomographic image is displayed, and when the ultrasonic probe 31 is a linear scan together with a radial, a three-dimensional ultrasonic tomographic image can be obtained. . The overall timing of this device is controlled by the system controller 43. Next, the configuration of the interpolation processing unit 39 will be described with reference to FIG.

The data read from the image memories 34 and 35 are input to weighting means 44 and 45. Weighting means 44 and 45 weight data read from the image memories 34 and 35. These weighting means 44, 4
The weighting ratio at 5 is controlled by weighting control means 46.

The weighting control means 46 comprises the weighting means 4
The result of adding the data read from 4, 45 is 100
% (For example, if one is weighted by 20%, the other is 80%, etc.).
The weighting means 44 and 45 can be constituted by a ROM in which a weighting table is written, or a circuit combining a bit shifter and an adder. The weight control means 46 is also constituted by a ROM or the like in which a weight control table is written.

The weighting means 44 and 45 use 1/8
In about steps, the adding means 47 becomes the weighting means 44, 4
5 is added. The operation of the embodiment configured as described above will be described below with reference to FIG.

It is assumed that the read address generation circuit 37 selects the pixel C, for example. The coordinate conversion circuit 38 converts the address generated by the read address generation circuit 37 so that the pixels A and B closest to C are read from the image memories 34 and 35 on the ultrasonic scanning lines a and b sandwiching the pixel C, respectively. Then, it is given to the image memories 34 and 35. As a result, the pixels A and B are read from the image memories 34 and 35 and input to the weighting means 44 and 45, respectively.

Assuming that the ratio of the distance between A and C to the distance between B and C is 4 to 6, the weighting control means 46 controls the weighting means 44 so that A is weighted 60% and B is weighted 40%. And 45 are weighted. These weighting means 4
The data weighted by 4 and 45 are added by the adding means 47. As a result, in the data output as the pixel C, an interpolation (correction) signal is generated using data obtained by weighting and interpolating the pixels A and B closest to the position of the pixel C according to the distance from the pixel C. .

According to this embodiment, no temporary storage means such as a buffer memory is required in addition to the image memories 34 and 35, so that the ultrasonic diagnostic apparatus can be reduced in size, power consumption and cost. . Further, according to the present embodiment, pixel data is read out from an ultrasonic scanning line sandwiching a pixel to be interpolated, weighted, and averaged and added, so that highly accurate interpolation can be performed.

As described above, according to this embodiment,
Alternating ultrasonic scanning lines are alternately arranged in two divided image memories 34 and 35 (for example, even-numbered ultrasonic scanning lines are written in one image memory and odd-numbered ultrasonic scanning lines are written in the other image memory). , And two data (data of adjacent ultrasonic scanning lines) are simultaneously read out and interpolated one by one from each of the two image memories 34 and 35. Without the need for temporary storage means such as memory,
Moreover, interpolation can be performed from the nearest pixel on the ultrasonic scanning line sandwiching the pixel to be interpolated. For this reason, since the scale of the DSC circuit can be reduced while enabling high-precision interpolation, the size and power consumption of a high-performance ultrasonic diagnostic apparatus can be reduced.
Low cost can be achieved. Instead of rotationally driving the vibrator, the mirror disposed opposite to the vibrator may be rotationally driven to perform ultrasonic radial scanning or radial and linear scanning.

FIG. 3 shows a tip side of an ultrasonic probe (ultrasonic probe) according to a second embodiment of the present invention. In FIG. 3, a housing 5 holding a first ultrasonic transducer 51
By transmitting and receiving ultrasonic waves while moving the 2 in the sheath 53 in the longitudinal direction and performing radial scanning,
A three-dimensional ultrasonic tomographic image is obtained, and the position of the housing 52 in the sheath 53 is detected by a second ultrasonic vibrator 54 provided at the tip of the housing 52. Things.

A housing 52 is fixed to one end of the shaft 55 as shown in the figure, and the other end is connected to an advancing / retracting driving means (not shown) for reciprocating motion and a rotary driving means for rotating and driving. The flexible shaft 55 is rotationally driven around the shaft 55 by the driving force generated by the rotation driving means, and the flexible shaft 55 is moved in the longitudinal direction of the shaft 55 by the driving force generated by the forward / backward driving means. Will be retired. This causes the housing 52 to spirally advance and retreat within the sheath 53. (The vibrator 51 may be attached to the tip of a screw, and the rear end of the screw may be rotationally driven to advance and retreat in a helical manner without separately providing the advance / retreat driving means and the rotation driving means.) A first ultrasonic transducer 51 is held on one side surface. The inside of the sheath 53 is filled with an ultrasonic transmission medium (for example, liquid paraffin) whose ultrasonic propagation speed is known. While moving the housing 52 spirally within the sheath 53, the first
By transmitting and receiving ultrasonic waves from the ultrasonic transducer 51, the scanning is performed spirally. A second ultrasonic transducer 54 is provided at the tip of the housing.

When an ultrasonic wave is transmitted from the second ultrasonic vibrator 54, the ultrasonic wave is reflected by the distal end portion 57 of the sheath 53 and returns to the second ultrasonic vibrator 54. The ultrasonic propagation speed of the ultrasonic transmission medium is known (for example, 1 for liquid paraffin)
420 m / sec), so that the time from transmission of the ultrasonic wave from the second ultrasonic vibrator 54 to reception of the echo reflected by the sheath distal end portion 56 is reduced.
The relative position within 3 is known.

FIG. 4 shows the overall configuration of this embodiment. FIG.
In response to the timing signal A generated by the second control circuit 60, the second transmission circuit 61 applies a high-voltage pulse to the second ultrasonic vibrator 54,
4 transmit an ultrasonic wave. The ultrasonic echo reflected from the sheath distal end 56 is received by the second ultrasonic transducer 54 again. The echo received by the second ultrasonic transducer 54 is converted into an electric signal and amplified by the second receiving circuit 62.

The first control circuit 63 includes a second receiving circuit 6
2, the reception signal B and the transmission timing signal A 'are input. The first control circuit 63 calculates a relative distance between the housing 52 and the distal end portion 56 of the sheath 53 from a time interval from transmission to reception (time difference between the timing signal A ′ and the reception signal B ′), When the housing 52 moves by a predetermined distance, a timing signal C ′ is output to the first transmission circuit 64.

The first transmission circuit 64 generates a timing signal C '
, A high-voltage pulse is applied to the first ultrasonic transducer 51. The ultrasonic wave transmitted from the first ultrasonic transducer 51 is reflected by a tissue of a living body or the like, and is received by the first ultrasonic transducer 51 again. The echo received by the first ultrasonic transducer 51 is converted into an electric signal and amplified by the first receiving circuit 65. The reception signal amplified by the first reception circuit 65 is converted into a television signal by the signal conversion circuit 66 and displayed on the display device 67.

Next, the operation will be described with reference to FIG. The timing signal A 'is generated at regular time intervals T1 as shown in FIG. The signal is received with a delay of time T2 corresponding to the distance between the housing 52 and the sheath distal end portion 56. Sheath 53
Since the ultrasonic wave propagation velocity of the ultrasonic transmission medium without the gap is known, the distance between the housing 52 and the sheath distal end portion 56 can be known from the time T2. When the housing moves by a predetermined distance, a timing signal C 'is output.

According to this embodiment, in addition to the effects of the first embodiment, no mechanical position detecting means is required. Since the relative position of the housing 52 with respect to the sheath 53 can be accurately measured, transmission and reception of ultrasonic waves from the first ultrasonic transducer 51 can be controlled at equal intervals, and a more accurate ultrasonic image can be formed. become. That is, since one detection in the linear direction is electrically performed, the position can be detected with a simpler configuration and more accurately than in the case where the position detection is performed mechanically for both the radial and the linear. The configuration of the operation unit is also simplified.

Next, a modification of the second embodiment will be described. In this modification, multiple distances can be measured by one transmission by using multiple echoes. The configuration is the same as in the second embodiment.

When an ultrasonic wave is transmitted from the second ultrasonic vibrator 54, the echo of the ultrasonic wave reflected on the sheath distal end portion 56 is reflected again on the surface of the second ultrasonic vibrator 54. Once the ultrasonic wave is transmitted in this manner, the ultrasonic wave repeats reciprocating between the second ultrasonic transducer 54 and the sheath distal end portion 56 while being attenuated. This appears as a multiple echo (b1, b2, b3) in the received signal as shown at B 'in FIG.

The distance between the housing 53 and the sheath distal end portion 56 can be measured from the interval between the multiple echoes.
According to this modification, since the distance can be measured a plurality of times by one transmission of the ultrasonic wave, the number of times of transmitting the ultrasonic wave can be reduced, and the power consumption can be reduced. The life of the sonic vibrator is prolonged.

[0043]

As described above, according to the present invention, every other ultrasonic scanning line is alternately written in the two divided image memories, and each of the two image memories is adjacent to each other. Since the data of the sound wave scanning lines are simultaneously read and interpolated, there is no need for a temporary storage unit such as a buffer memory other than the image memory, so that the scale of the DSC circuit can be reduced and the cost can be reduced. Interpolation becomes possible.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a configuration of an interpolation processing unit.

FIG. 3 is a perspective view showing a distal end side of an ultrasonic probe according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a signal processing system of the ultrasonic diagnostic apparatus according to the second embodiment.

FIG. 5 is an operation explanatory diagram of the second embodiment.

FIG. 6 is an operation explanatory diagram of a modification of the second embodiment.

FIG. 7 is an explanatory diagram of sector scanning.

FIG. 8 is an explanatory diagram of radial sector scanning.

FIG. 9 is an explanatory diagram showing a state in which an ultrasonic image is displayed along a scanning line in rectangular coordinates.

FIG. 10 is an explanatory diagram showing a state in which image data is lost when scanning with polar coordinates.

FIG. 11 is a block diagram illustrating a configuration of a signal processing system of a conventional ultrasonic diagnostic apparatus.

FIG. 12 is a block diagram showing a configuration of a conventional interpolation processing unit.

FIG. 13 is a block diagram showing a configuration of a signal processing system of a conventional ultrasonic diagnostic apparatus.

FIG. 14 is a block diagram showing a configuration of a conventional interpolation processing unit.

[Explanation of symbols]

 Reference Signs List 31 ultrasonic probe 32 transmission / reception circuit 33 A / D converter 34, 35 image memory 36 write address generation circuit 37 read address generation circuit 38 coordinate conversion circuit 39 interpolation processing unit 41 D / A conversion Device 42 display device 43 system controller 44, 45 weighting means 46 weight control means 47 addition means

Claims (1)

(57) [Claims] A scanning unit that scans an ultrasonic wave in a polar coordinate system; and a receiving unit that receives the ultrasonic wave scanned by the scanning unit.
Means for controlling the writing of the ultrasonic scanning lines received by the receiving means.
A first and a second image memory for storing pixel information on polar coordinates based on a signal; and an ultrasonic scanning line for the first and the second image memory.
Are written alternately every other line.
Are alternately output to the first and second image memories.
And writing control means that, the first, before the polar coordinates stored in the second image memory
A specific pixel in the area specified by the pixel information
Indicating means for indicating in rectangular coordinates, and the pixel on polar coordinates stored in the first image memory
Of the information, the pixel specified by the
Reading near first pixel information from the first image memory
And on the polar coordinates stored in the second image memory.
Of the pixel information indicated by the instruction means
The second pixel information closest to the pixel is stored in the second image memory.
From the first and second image memories by the reading means.
Based on the first and second pixel information read from
A pixel for creating the information of the pixel specified by the specifying means;
An ultrasonic diagnostic apparatus, comprising: information creating means ;