JPH11178822A - Ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an ultrasonograph having a mechanical scan type ultrasonic probe to have angular resolution not smaller than the angular resolution (bearing resolution of ultrasonic beam) which a rotary encoder originally has. SOLUTION: An integration circuit 30 integrates encoder output pulses 100 to produce a sawtoothed integration signal. A dc voltage generator 32 produces a plurality of different dc voltages based on a resolution designating signal 104. Each of comparators constituting a comparator array 34 compares the integration signal 108 with the dc voltages, and outputs pulses when they are coincident. A synthesizer 36 synthesizes the pulses to produce a fractionalized pulse 106. The fractonalized pulse 106 is used in controlling transmission and reception.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus in which an ultrasonic vibrator is rotationally driven (including an arc drive).

[0002]

2. Description of the Related Art Conventional mechanical scanning ultrasonic probes include a mechanical sector probe that reciprocates an ultrasonic transducer along an arc, and a radial scanning probe that rotationally drives an ultrasonic transducer. Etc. are known. In recent years, ultrasonic probes for three-dimensional data acquisition have also been put to practical use. Among such probes, those that perform mechanical scanning such as an array transducer are also used in the mechanical scanning ultrasonic probe described above. is there.

A conventional mechanical scanning ultrasonic probe has a rotary encoder as a rotation angle detector for detecting the rotation angle (oscillation angle) of a transducer. Such a sensor is generally mounted on a shaft of a motor, or mounted on a shaft that rotationally drives a vibrator. The optical rotary encoder transmits and receives light on both sides of a slit plate in which a plurality of slits are radially formed, and outputs a pulse at the light passage timing of the slit plate.

[0004]

Therefore, the resolution of the detection angle is determined by the number of slits of the rotary encoder. For example, when it is desired to set the number of ultrasonic beams densely, it is necessary to set the direction of the ultrasonic beam at a smaller angle, but in that case, there is a problem that the number of slits of the rotary encoder must be increased. is there. For example, there is a rotary encoder that outputs a plurality of signals having different phases by using a plurality of slit plates. However, if there is a problem in processing accuracy or assembly accuracy of each slit plate, it is difficult to obtain a uniform resolution. In any case, there is a structural limitation in trying to obtain an arbitrary angular resolution using only the rotary encoder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to control the transmission and reception of ultrasonic waves by providing an angular resolution (azimuth resolution of an ultrasonic beam) that is higher than the angular resolution inherent to a rotary encoder. It is to provide an obtained ultrasonic diagnostic apparatus.

[0006]

In order to achieve the above object, the present invention provides an ultrasonic vibrator for transmitting and receiving ultrasonic waves,
A rotation mechanism for rotating the ultrasonic vibrator, a rotation angle detector for detecting a rotation angle in the rotation movement, a rotation angle detector for generating a first pulse signal for each predetermined angle, and the first pulse A multiplying circuit that generates a second pulse signal having an interval shorter than that of the pulse signal based on the signal, a control unit that performs scanning control of the ultrasonic beam based on the second pulse signal, It is characterized by including.

According to the above configuration, the rotation angle of the ultrasonic transducer is detected by the rotation angle detector, and as a result, the first pulse signal is generated. The multiplying circuit generates a second pulse signal having a shorter cycle based on the first pulse signal. If the scanning control of the ultrasonic beam is performed based on the second pulse signal, the azimuth resolution can be further improved.

Preferably, the multiplying circuit generates the second pulse signal according to a rotation speed and a multiplication number. When the rotation speed is changed, the pulse interval changes accordingly, so that the multiplication process is performed in consideration of the rotation speed. Further, since the required azimuth resolution changes according to various transmission / reception conditions such as the number of ultrasonic beams, the scanning range, and the diagnostic depth, the multiplication factor is variably set accordingly.

Preferably, the multiplying circuit outputs an integration signal proportional to a rotation angle between the first pulse signals, and a voltage signal generation circuit for generating a plurality of voltage signals to be compared with the integration signal. And a pulse generation circuit that compares the integration signal with the plurality of voltage signals to generate the second pulse signal. According to this configuration, since the multiplication process can be performed by a simple method such as integration and voltage comparison, the device configuration can be simplified and the device cost can be reduced.

Preferably, the multiplying circuit is an integrating circuit for outputting an integral signal proportional to a rotation angle between the first pulse signals, and means capable of switching and generating a plurality of voltage signals, and the means for switching and generating a plurality of voltage signals according to the count signal. A voltage generation circuit for switching and outputting a voltage signal in a stepwise manner, a match determination circuit for determining a match between the voltage signal output from the voltage generation circuit and the integration signal, and outputting a match signal; A circuit for outputting a signal, wherein the counter counts up when the coincidence signal is output, and the count value is reset at an input timing of the first pulse signal. The second pulse signal is constituted by the following. According to this configuration, there is an advantage that it is not necessary to provide a large number of comparators.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration.

In FIG. 1, an ultrasonic probe 10 has an ultrasonic transducer 12 for transmitting and receiving ultrasonic waves. The ultrasonic transducer 12 is connected to a drive motor 14 and is driven to rotate by the drive motor 14. Thus, the ultrasonic beam is radially scanned or sector-scanned. FIG. 2 shows a scanned image. FIG. 2 will be described later.

A rotary encoder 16 is connected to the motor shaft of the drive motor 14, and the rotary encoder 16 detects the rotation angle of the ultrasonic transducer 12. Specifically, the encoder output pulse 100 is output from the rotary encoder 16 every time the ultrasonic transducer 12 rotates by a certain angle.

The control unit 18 controls the entire ultrasonic diagnostic apparatus, and particularly controls the transmission / reception circuit 20 based on a subdivided pulse 106 from a multiplying circuit 22 described later. That is, transmission / reception control is performed. Further, the control unit 18 controls the drive motor 14, whereby the mechanical scanning itself is also controlled by the control unit 18.

The transmission / reception circuit 20 is a circuit that supplies a transmission signal to the ultrasonic vibrator 12 and processes a reception signal output from the ultrasonic vibrator 12. Transmission / reception circuit 2
The received signal output via the line 0 is input to the image processing circuit 24, where an ultrasonic image such as a B-mode image or a Doppler image is formed. The ultrasonic image is displayed on the display 26.

The multiplier circuit 22 receives an encoder output pulse 100 output from the rotary encoder 16. The speed signal 102 and the resolution specifying signal 104 are input from the control unit 18 to the multiplying circuit 22. The speed signal 102 is a signal indicating the rotational speed of the ultrasonic transducer 12, and for example, in the case of radial scanning, the speed signal 102 usually indicates a constant value. However, for example, when the ultrasonic transducer 12 is reciprocally scanned in an arc shape,
The speed signal 102 has a value according to the reciprocation. The resolution designation signal 104 is a signal representing a resolution determined by the control unit 18 according to, for example, the number of necessary ultrasonic beams, a scanning range, or a range to be imaged. Specifically, the resolution designation signal 104 designates the number of multiplications for the encoder output pulse 100. For example, an operation panel or the like is connected to the control unit 18, and the user sets and sets transmission / reception conditions on the operation panel.

As described above, the control unit 18 multiplies the encoder output pulse 100 to generate the subdivided pulse 10.
6, transmission and reception control of ultrasonic waves is performed. Also,
Information necessary for image processing is provided from the control unit 18 to the image processing circuit 24. The information includes, for example, information such as azimuth resolution.

FIG. 2 shows specific images of mechanical radial scanning and mechanical sector scanning.
In FIG. 2, reference numeral 200 denotes a scanning surface. (A)
In the mechanical radial scanning shown in FIG.
Indicates a beam address corresponding to the encoder output pulse 100, and reference numeral 106A indicates a beam address corresponding to the subdivided pulse 106 generated by the multiplier circuit 22. As described above, only a rough azimuth resolution can be obtained as shown by 100 A only by the output of the rotary encoder 16, but a necessary azimuth resolution can be obtained by generating the subdivided pulse 106 in the multiplying circuit 22. It is. Of course, the resolution is set based on various transmission / reception conditions, and in some cases, the multiplication number is set to 1, in which case the multiplication is not performed substantially. The same applies to the mechanical sector scanning shown in (B), in which a plurality of beam addresses 106A generated by multiplication are generated between beam addresses 100A corresponding to the encoder output pulses 100 output from the rotary encoder 16. However, in the case of the mechanical sector scanning, since a speed change occurs at both ends of the reciprocating motion, a waveform is generated based on the speed change in generating the integration signal as described later. Therefore, the speed signal 102 is input to the multiplying circuit 22 as described above.

FIG. 3 shows a specific configuration example of the multiplying circuit 22 shown in FIG.

The integration circuit 30 has an encoder output pulse 1
00 is input, and the integration circuit 30 integrates the encoder output pulse 100 to generate an integration signal 108. The integration circuit 30 is reset by the encoder output pulse 100 itself, so that a sawtooth integration signal 108 is generated in synchronization with the encoder output pulse 100. In that case, the slope of the waveform is the speed signal 102
Is set based on The integration signal 108 is output to the comparator group 34
Are input to one input terminal of each comparator.

The DC voltage generator 32 outputs the resolution specifying signal 1
04 according to the resolution (n) designated by
8, a plurality of different DC voltages DC1 to DC
This is a circuit for generating Cn. Each of these DC voltage signals is input to the other input terminal of the comparator. Then, each comparator compares the integrated signal with the DC voltage signal, and outputs a coincidence signal when the coincidence is obtained. A combiner 36 is provided at the subsequent stage of the comparator group 34, and the combiner 36 combines the coincidence signals output from the above-described comparators. At this time, the encoder output pulse 100 is also synthesized. Then, the synthesizer 36 synthesizes each of such pulses to generate the subdivided pulse 106.

FIG. 4 shows the waveform of each signal in the multiplying circuit 22 shown in FIG. As described above, the integration signal 108 is generated in synchronization with the encoder output pulse 100, and the integration signal is compared with each DC voltage. Then, a pulse is generated at the coincidence timing of each voltage value, and the subdivided pulse 106 is synthesized by the pulse. As described above, the subdivided pulse 106 is input to the control unit 18 and is used for setting a scan address when scanning the ultrasonic beam.

FIG. 5 shows another embodiment of the multiplying circuit 22.

As described above, the encoder output pulse 100 is input to the integration circuit 30, and the integration circuit 30 generates an integration signal 108 in synchronization with the encoder output pulse 100 based on the speed signal 102. On the other hand, the resolution specifying signal 104 is input to the DC voltage generator 32 as described above, and the DC voltage generator 32 generates a plurality of DC voltage values. The selector 40 selects one of the plurality of generated DC voltages, and the selected DC voltage is input to the comparator 42. Comparator 4
In 2, the integrated signal 108 and the DC voltage are compared, and a coincidence pulse is output when the two coincide.

The counter 44 counts the coincidence pulses, and the count value of the counter 44 is input to the selector 40 as a count signal. Selector 40
Selects the voltage value of the number represented by the count value. The counter 44 is reset by the encoder output pulse 100. Therefore, according to the circuit configuration shown in FIG. 5, since the DC voltage can be sequentially switched by the feedback loop including the counter 44 and compared with the integrated signal, there is an advantage that it is not necessary to provide a large number of comparators.
Note that a specific circuit configuration example of the multiplication circuit 22 is shown in FIG.
The present invention is not limited to the configuration shown in FIG. 5, and an example of a circuit configuration using a technology such as digital signal processing is also conceivable.

[0027]

As described above, according to the present invention, in an ultrasonic diagnostic apparatus having a mechanical scanning type ultrasonic probe, it is possible to obtain an angular resolution higher than the angular resolution originally possessed by a rotary encoder. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 2 is a conceptual diagram illustrating a specific image of mechanical radial scanning and mechanical sector scanning.

FIG. 3 is a circuit diagram showing an embodiment of a multiplier circuit.

FIG. 4 is a timing chart showing each signal of the multiplier circuit.

FIG. 5 is a circuit diagram showing another embodiment of the multiplication circuit.

[Explanation of symbols]

10 ultrasonic probe, 12 ultrasonic transducer, 14 drive motor, 16 rotary encoder, 18 control unit,
Reference Signs List 20 transmission / reception circuit, 22 multiplication circuit, 24 image processing circuit, 26 display, 100 encoder output pulse, 1
02 speed signal, 104 resolution designation signal, 106 subdivided pulse.

Claims (4)

[Claims] 1. An ultrasonic transducer for transmitting and receiving ultrasonic waves, a rotating mechanism for rotating the ultrasonic transducer, and a means for detecting a rotation angle in the rotational movement, wherein a rotation angle of the ultrasonic transducer is determined at every predetermined angle. A rotation angle detector that generates one pulse signal; a multiplying circuit that generates a second pulse signal having an interval shorter than the interval between the pulse signals based on the first pulse signal; An ultrasonic diagnostic apparatus comprising: a control unit configured to perform scanning control of an ultrasonic beam based on the pulse signal. 2. The device according to claim 1, wherein the multiplying circuit is configured to control the second power according to a rotation speed and a multiplying factor.
An ultrasonic diagnostic apparatus characterized by generating a pulse signal. 3. The apparatus according to claim 1, wherein the multiplying circuit outputs an integration signal proportional to a rotation angle between the first pulse signals, and a plurality of voltages to be compared with the integration signal. An ultrasonic diagnostic apparatus comprising: a voltage signal generation circuit that generates a signal; and a pulse generation circuit that compares the integration signal and the plurality of voltage signals to generate the second pulse signal. 4. The device according to claim 1, wherein the multiplying circuit is configured to output an integration signal proportional to a rotation angle between the first pulse signals, and to switch and generate a plurality of voltage signals. A voltage generation circuit for switching and outputting a voltage signal in a stepwise manner in accordance with a count signal; determining a match between the voltage signal output from the voltage generation circuit and the integration signal; and outputting a match signal. A match determination circuit, a circuit that outputs the count signal, and counts up a count value when the match signal is output;
An ultrasonic diagnostic apparatus, comprising: a counter that resets a count value at an input timing of the first pulse signal, wherein the coincidence signal forms the second pulse signal.