JPH04332547A - Ultrasonic diagnosis device - Google Patents

Abstract

PURPOSE:To eliminate the need for buffer memories and to reduce the sizes of circuits by providing 1st and 2nd image memories which subject ultrasonic wave reception signals to A/D conversion and store the outputs thereof, a writing control means which alternately executes the writing to these memories, a reading out address generat ing circuit which reads the signals out of the memories, etc. CONSTITUTION:The reflection wave signals taken out of a signal transmission/reception circuit 32 are digitized by an A/D converter 33 and are written alternately by every other ultrasonic scanning line into the image memories 34, 35. The writing of the signal data to the respective image memories 34, 35 is executed successively in accordance with the address signals generated by a writing address generating circuit 36. The reading out address generating circuit 37 generates the reading out addresses of the image memories. After the reading out addresses are converted to polar coordinates by a coordinate conversion circuit 38 and are applied to the image memories 34, 35, these addresses are inputted to an interpolation processing section 39 and are converted by a D/A converter 41 to analog signals which are displayed on a display device 42 and, therefore, the sizes of the circuits can be reduced without requiring the buffer memories.

Description

[Detailed description of the invention]

0001

[Industrial application field]

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

[Prior Art] Ultrasonic pulses are transmitted from an ultrasound probe into a living body, and echoes of the ultrasound pulses reflected from the living body are received by the same or a separate ultrasound probe.
BACKGROUND ART Various ultrasound diagnostic apparatuses have been devised in the past that are capable of displaying information collected from multiple directions within a living body as a visible image by transmitting and receiving ultrasound pulses while shifting the direction.

Among such ultrasonic diagnostic apparatuses, as shown in FIG. 7, there is a sector scanning type that scans a fan-shaped area with respect to the ultrasonic probe 1, and as shown in FIG. There are devices that perform ultrasonic scanning in polar coordinates, such as a radial sector scanning type that scans a circular area. Such an ultrasonic diagnostic apparatus has the advantage of being able to achieve a wide field of view with a small probe. In particular, in an intrabody cavity scanning type device such as an ultrasound endoscope, a radial sector scanning type is often used because it can scan the entire circumference of the lumen.

[0004] In an ultrasonic diagnostic apparatus, a television monitor that displays an image by scanning in orthogonal coordinates as shown in FIG. 9 is generally used as a display device for displaying an ultrasonic image. Even the device that scans ultrasonic waves in polar coordinates as described above has a means for converting the ultrasonic scan in polar coordinates into television scan in rectangular coordinates, and displays the ultrasound image on a television monitor. There is. This is because if you convert the scanning method to television scanning, you can switch between multiple ultrasound probes with different ultrasound scanning methods and display them on the same display device. This is because various developed inexpensive and high-performance hard copy devices (eg, video printers, etc.) and auxiliary storage devices (eg, VTRs, etc.) 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 it into rectangular coordinates. A means for converting the scanning method from polar coordinate scanning to orthogonal coordinate scanning is called a scan converter. Today, a digital scan converter (DSC) is commonly used as such a scan converter.

[0006] DSC is a system that converts ultrasonic echo signals (analog signals) into digital signals and displays them on a television display 1.
Data is once written into an image memory consisting of a digital memory having a storage capacity equivalent to a screen according to an ultrasonic scanning method, and read out according to a television scanning method.

[0007] By using such a DSC, it is possible to display an image scanned by ultrasonic waves in polar coordinates on a television monitor, but as shown in FIG. Since the distance between the two increases as the distance from the probe increases, there are addresses in the image memory where no image signal data is written (blank areas).

[0008] Therefore, interpolation is necessary to fill in addresses to which no image signal data has been written. For this reason, for example, in Japanese Patent Publication No. 2-28870, there is a conventional example in which interpolation is applied by writing into an image memory, as shown in FIGS. 11 and 12. The ultrasonic probe 1 emits ultrasonic waves to the subject based on transmission pulses from the transmitting/receiving circuit 2, and also receives reflected ultrasound signals reflected from discontinuous portions of the acoustic impedance of the subject and outputs them to the transmitting/receiving circuit 2. , this transmitting/receiving circuit 2 outputs ultrasonic echoes to an A/D converter 3.

The digital signal converted by the A/D converter 3 is input to an interpolation processing section 4, where interpolation processing is performed and the signal is written into an image memory 5. The data written in the image memory 5 is input to the D/A converter 6, converted to an analog signal, and then passed through a DSC (not shown).
The tomographic image is output to the television monitor 7 and displayed. Each circuit is controlled by a system controller 8.

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

[0011] Furthermore, FIGS. 13 and 14 are
This is disclosed in No. 871, in which interpolation is applied when reading an image memory. In this conventional example, when a pixel with no data is detected when reading data from an image memory in synchronization with the horizontal scanning of a television, it is filled in by averaging the pixels on both sides of the same horizontal scanning line. It is.

The configuration of FIG. 13 differs from FIG. 11 in that an image memory 5 is interposed before the interpolation processing section 4, and the interpolation processing section 4 contains data (sector pattern) that is not stored with image data from the sector pattern memory 9. ) is now entered. The configuration of the interpolation processing section 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 this latch (1) 21 is input to the latch (2) 22 and also to the selector 24. The output α of the latch (2) 22 is obtained by the averaging section 23
The average value of the average unit 23 is input to the selector 2.
4, it is outputted from D/A 26 inverter 6 to 5.

[0013]

[Problem to be solved by the invention] Japanese Patent Publication No. 2-28870
In the circuit configuration that performs interpolation when writing to the image memory 5, which is described in the above publication, the interpolation processing section 4 is provided in the preceding stage of the image memory 5. Such an interpolation processing unit 4 is shown in FIG.
As shown in the figure, three buffer memories 12, 13, and 14 are required (to write the data coming from the receiving circuit into the remaining one buffer memory while reading data from two buffer memories and applying interpolation). Therefore, there is a problem that the circuit scale becomes large and the circuit configuration becomes complicated.

Furthermore, in the circuit configuration described in Japanese Patent Publication No. 2-28871, pixels are read from the image memory 5 according to television scanning, pixels with no data are detected, and pixels on both sides of the same horizontal scanning line are read out. Since the data is simply averaged to fill in that pixel, interpolation is not necessarily performed between pixels closest to the pixel to be interpolated, so there was a problem that the accuracy of interpolation was not good. .

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, and can realize a DSC circuit with a small scale and low cost, and has high precision. The purpose of the present invention is to provide an ultrasonic diagnostic device that can perform interpolation.

[0016]

[Means for Solving the Problems] The present invention provides a scanning means for scanning ultrasonic waves in polar coordinates, an A/D converting means for converting a received signal of the ultrasonic waves into a digital signal, and an A/D converting means for converting the received signal of the ultrasonic wave into a digital signal. first and second image memories that store output signals; write control means that corresponds to the scanning line of the ultrasonic wave and alternately controls writing to the first and second image memories; and the first image memory. and read signal generating means for generating a read signal for reading the signal stored in the second image memory;
a coordinate conversion circuit that reads out signals at specific locations from the first and second image memories based on the readout signal; and a correction signal that generates a correction signal from the signals read out from the first and second image memories. An ultrasonic diagnostic apparatus comprising a generation circuit, a D/A conversion means for converting the correction signal into an analog signal, and a display means for displaying the analog signal converted by the D/A conversion means as an image. It consists of

[0017]

[Operation] Ultrasonic signals converted to digital signals are stored in the two image memories alternately for every other ultrasonic scanning line (for example, even-numbered signals are stored in one image memory, and odd-numbered signals are stored in the other image memory). (such as an ultrasonic scan line). One piece of data from each of the two image memories (total of two pieces) can be read out at the same time.

With this configuration, it is possible to simultaneously read out the closest pixels on the ultrasonic scanning line sandwiching a certain pixel to be interpolated, without requiring a temporary storage means such as a buffer memory in addition to the image memory. can be weighted and interpolated.

[0019]

Embodiments Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. 1 and 2 relate to a first embodiment of the present invention; FIG. 1 shows the configuration of a signal processing system of an ultrasonic diagnostic apparatus according to the first embodiment, and FIG. 2 shows the configuration of an interpolation processing section.

In this 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). It is characterized in that a total of two data (data of adjacent ultrasonic scanning lines) are read out and interpolated at the same time, one from each of the two image memories.

The ultrasonic probe 31 shown in FIG. 1 is attached to a shaft that is rotationally driven by a motor (not shown), and this ultrasonic probe 31 is applied to a subject inside the body by mechanical radial scanning or mechanical radial and linear scanning. Ultrasonic waves are emitted while shifting the angle little by little or while shifting the angle little by little in the axial direction (longitudinal direction) of the probe 31. Transmission/reception circuit 3
2 applies electrical pulses to the ultrasound probe 31 to cause the ultrasound probe 31 to emit ultrasound into the body, and processes echoes of the ultrasound received by the ultrasound probe 31 such as amplification and detection. do.

A series of reflected wave signals taken out from the transmitter/receiver circuit 32 are sequentially sampled at a constant period by an A/D converter 33 and digitized. The signal data digitized by this A/D converter 33 is written into image memories 34 and 35 alternately for every other ultrasonic scanning line. Writing of signal data to each image memory 34, 35 is performed sequentially in accordance with an address signal generated by a write address generation circuit 36.

The read address generation circuit 37 generates a read address for 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 a coordinate conversion table is written, and then provided to the image memories 34 and 35. The data read from the image memories 34 and 35 is input to an interpolation processing section 39. The data read out from the image memories 34 and 35 by the interpolation processing section 39 are weighted and added. The data interpolated by the interpolation processing section 39 is sent to the D/A converter 4.
1, the signal is converted into an analog signal and displayed on the display device 42.

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

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

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

Note that the weighting means 44 and 45 have a weight of 1/8.
The adding means 47 adds weighting means 44, 4 in steps of
Add the data read from 5. The operation of one embodiment configured in this way will be explained below using FIG. 10.

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

If the ratio of the distance between A and C to the distance between B and C is 4:6, 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 and controlled. These weighting means 4
The data weighted by 4 and 45 are added by an adding means 47. As a result, the data output as pixel C is interpolated by weighting the nearest pixels A and B across the position of C according to the distance from C, and generates an interpolation (correction) signal. .

According to this embodiment, there is no need for temporary storage means such as a buffer memory other than the image memories 34 and 35, so it is possible to downsize, save power, and lower the price of the ultrasonic diagnostic apparatus. . Furthermore, according to this embodiment, pixel data is read out from the ultrasonic scanning lines that sandwich the pixel to be interpolated, weighted, and averaged, so that highly accurate interpolation is possible.

As described above, according to this embodiment,
The ultrasonic scanning lines are alternately written into the two divided image memories 34 and 35 (even-numbered ultrasonic scanning lines are written into one image memory, odd-numbered ones are written into the other image memory, etc.). Since a total of two data (data of adjacent ultrasonic scanning lines) are simultaneously read out and interpolated, one from each of the two image memories 34 and 35, for example, a buffer is used in addition to the 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. Therefore, the scale of the DSC circuit can be reduced while high-precision interpolation is still possible, making it possible to reduce the size, power consumption, and cost of a high-performance ultrasonic diagnostic apparatus. Note that instead of rotationally driving the vibrator, a mirror disposed opposite to the vibrator may be rotationally driven to perform radial scanning or radial and linear scanning of the ultrasonic waves.

FIG. 3 shows the tip side of an ultrasonic probe in a second embodiment of the present invention. In this FIG. 3, the housing 5 holding the first ultrasonic transducer 51
2 in the longitudinal direction within the sheath 53 while transmitting and receiving ultrasonic waves and also performing radial scanning.
A three-dimensional ultrasonic tomographic image can be obtained, and the position of the housing 52 within the sheath 53 is detected by a second ultrasonic transducer 54 provided at the tip of the housing 52. It is something.

As shown, the housing 52 is fixed to one end of the shaft 55, and the other end is connected to forward and backward drive means (not shown) that moves forward and backward, and to rotational drive means that rotates. The flexible shaft 55 is rotationally driven around the shaft 55 by the driving force generated by the rotational drive means, and the flexible shaft 55 is rotated in the longitudinal direction of the shaft 55 by the driving force generated by the forward/backward driving means. will be advanced and retreated. As a result, the housing 52 moves spirally forward and backward within the sheath 53. (The vibrator 51 may be attached to the tip of the screw and the rear end of the screw may be rotationally driven to move the housing 52 forward and backward in a spiral manner, without providing separate forward and backward drive means and rotational drive means.) A first ultrasonic transducer 51 is held on one side. Inside the sheath 53 is an ultrasonic transmission medium (with known ultrasonic propagation velocity).
liquid paraffin). Scanning is performed in a spiral manner by transmitting and receiving ultrasonic waves from the first ultrasonic transducer 51 while moving the housing 52 back and forth in a spiral manner within the sheath 53. A second ultrasonic transducer 54 is provided at the tip of the housing.

When an ultrasonic wave is transmitted from the second ultrasonic transducer 54, the ultrasonic wave is reflected by the tip 57 of the sheath 53 and returns to the second ultrasonic transducer 54. The ultrasonic propagation velocity of the ultrasonic transmission medium is known (for example, 1 for liquid paraffin).
420 m/sec), therefore, the relative position of the housing 52 within the sheath 53 is calculated from the time from transmitting the ultrasound from the second ultrasonic transducer 54 to receiving the echo reflected at the sheath tip 56. I understand.

FIG. 4 shows the overall configuration of this embodiment. Figure 4
In response to the timing signal A generated by the second control circuit 60, the second transmitting circuit 61 applies a high voltage pulse to the second ultrasonic transducer 54, and the second ultrasonic transducer 5
4 to transmit ultrasonic waves. The echo of the ultrasound reflected from the sheath tip 56 is received again by the second ultrasound transducer 54. The echo received by the second ultrasonic transducer 54 is converted into an electrical signal and amplified by the second receiving circuit 62.

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

The first transmitting circuit 64 receives the timing signal C'
A high voltage pulse is applied to the first ultrasonic transducer 51 in accordance with the above. The ultrasonic waves transmitted from the first ultrasonic transducer 51 are reflected by the tissues of the living body and are received by the first ultrasonic transducer 51 again. The echo received by the first ultrasonic transducer 51 is converted into an electrical signal and amplified by the first receiving circuit 65. The received signal amplified by the first receiving circuit 65 is converted into a television signal by a signal conversion circuit 66 and displayed on a display device 67.

Next, the operation will be explained using FIG. 5. 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 tip 56. sheath 53
Since the ultrasonic propagation speed of the ultrasonic transmission medium is known, the distance between the housing 52 and the sheath tip 56 can be determined from time T2. When the housing moves 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 detection means is required. sheath 5
The relative position of the housing 52 with respect to the first ultrasonic transducer 51 can be measured accurately, and the transmission and reception of ultrasonic waves from the first ultrasonic transducer 51 can be controlled at equal intervals, making it possible to form more accurate ultrasonic images. Become. That is, since one detection in the linear direction is performed electrically, the configuration is simpler and the position can be detected with higher accuracy than when position detection is performed mechanically in both radial and linear directions. The configuration of the operating section is also simplified.

Next, a modification of the second embodiment will be explained. This modification uses multiple echoes to enable multiple distance measurements with one transmission. The configuration is the same as the second embodiment.

When the second ultrasonic transducer 54 transmits an ultrasonic wave, the echo of the ultrasonic wave reflected at the sheath tip 56 is reflected again on the surface of the second ultrasonic transducer 54. Once the ultrasonic waves are transmitted in this way, the ultrasonic waves repeat reciprocation between the second ultrasonic transducer 54 and the sheath tip 56, although they are attenuated. This appears as multiple echoes (b1, b2, b3) in the received signal as shown in B' of FIG.

The distance between the housing 53 and the sheath tip 56 can also be measured from the interval between the multiple echoes.
According to this modification, distance can be measured multiple times by transmitting an ultrasonic wave once, so the number of times the ultrasonic wave is transmitted can be reduced, and power consumption can be reduced. The lifespan of the sonic vibrator is extended.

[0043]

As described above, according to the present invention, every other ultrasonic scanning line is written in an image memory divided into two, and each adjacent ultrasonic scanning line is written from each of the two image memories. Since the data of the sonic scanning lines are simultaneously read out and interpolated, there is no need for a temporary storage means such as a buffer memory in addition to the image memory, and the DSC circuit can be realized on a small scale and at low cost, and can be realized with high accuracy. Interpolation becomes possible.

[Brief explanation of drawings]

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

FIG. 2 is a block diagram showing the configuration of an interpolation processing section.

FIG. 3 is a perspective view showing the tip side of an ultrasound probe in a second embodiment of the present invention.

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

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

FIG. 6 is an explanatory diagram of the operation 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 how an ultrasound image is displayed along orthogonal coordinate scanning lines.

FIG. 10 is an explanatory diagram showing how image data is lost when performing polar coordinate scanning.

FIG. 11 is a block diagram showing the configuration of a signal processing system of a conventional ultrasound diagnostic apparatus.

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

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

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

[Explanation of symbols]

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 section 41...D/A converter 42...Display device 43...System controller 44, 45...Weighting means 46...Weighting control means 47... Addition means

Claims (1)

[Claims] 1. A scanning means for scanning ultrasonic waves in polar coordinates, an A/D conversion means for converting a received signal of the ultrasonic waves into a digital signal, and a first apparatus for storing an output signal of the A/D conversion means. and a second image memory, a write control means that corresponds to the scanning line of the ultrasonic wave and alternately controls writing to the first and second image memories, and a readout signal generating means for generating a readout signal for reading out a stored signal; a coordinate conversion circuit for reading out signals at specific locations from the first and second image memories based on the readout signal; a correction signal generation circuit that generates a correction signal from a signal read out from the image memory; a D/A converter that converts the correction signal into an analog signal; and a D/A converter that converts the analog signal converted by the D/A converter. An ultrasonic diagnostic apparatus comprising: display means for displaying an image.