JP3000554B2 - Dual beam ultrasonic detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a transducer comprising an electrostrictive transducer having a plurality of electrodes formed thereon or a transducer comprising a plurality of electrostrictive transducers each having an electrode formed thereon. More specifically, the present invention relates to an ultrasonic detection apparatus, and more specifically, a quasi-ideal beam that performs weighting between an electrode and a drive signal source that drives a transmitter / receiver so that a beam transmitted from the transmitter / receiver becomes a quasi-ideal beam. The present invention relates to a dual-beam ultrasonic detection device having a weight inserted therein.

[0002]

2. Description of the Related Art In an ultrasonic detection device, the sensitivity is constant within the range of the directional angle of a beam when the reflection intensity of an object is to be accurately detected. It is necessary to use an ideal beam having different directional characteristics. However, realizing such an ideal beam requires a transducer having an infinite size, which is not possible.However, there has been proposed an apparatus for making the directional characteristics closer to the ideal beam. (3-23874).

In this apparatus, a quasi-ideal beam weight is inserted between a plurality of electrodes formed on an electrostrictive vibrator and a signal source for driving the electrostrictive vibrator, thereby obtaining an amplitude calculated by a Bessel function. Weighting is performed to give a signal of the same phase to each electrode, and at the time of reception, a received signal from the electrode is extracted through a quasi-ideal beam weight unit that gives similar weighting. FIG. 5 shows the directional characteristics realized by this device.
The sensitivity is almost constant in the range of the directivity angle d91, and the sensitivity in the range d92 exceeding the directivity angle decreases rapidly as the distance from the directivity angle increases. It has become.

[0004]

The directional characteristic realized by the above-described apparatus is similar to the ideal beam as described above, but the object is located in a range d93 slightly away from the directional angle. In such a case, since the detection sensitivity is in a range where the detection sensitivity changes, there is a problem that the reliability of the signal indicating the reflection intensity of the target is reduced, and the reliability of the obtained data itself is reduced.

The present invention has been conceived in order to solve the above-mentioned problem, and an object of the present invention is to provide an ultrasonic detecting apparatus which is close to an ideal beam in order to improve the reliability of obtained data.

[0006]

In order to solve the above-mentioned problems, a dual-beam ultrasonic detecting apparatus according to the present invention comprises a transducer comprising an electrostrictive vibrator having a plurality of electrodes formed thereon, or an electrode formed on each transducer. A transducer comprising a plurality of electrostrictive vibrators, and weighting between the electrode and a drive signal source for driving the transducer so that the beam shape transmitted from the transducer becomes a quasi-ideal beam. Applying to the ultrasonic detection device with the quasi-ideal beam weight part inserted, the output of the electrode is guided,
A quasi-ideal beam weight unit for weighting the reception characteristics to be a quasi-ideal beam, a Chebyshev weight unit for guiding the output of the electrode to weight the reception characteristics to a Chebyshev beam, and an output of the Chebyshev weight unit Is larger than the output of the quasi-ideal beam weight unit, the output of the quasi-ideal beam weight unit is sent out, and at other times, a gate unit is provided which sets the output to a level near zero.

[0007]

The relationship between the sensitivity curve of the Chebyshev beam and that of the quasi-ideal beam is determined by setting the level where the sensitivity curve of the quasi-ideal beam crosses the sensitivity curve of the Chebyshev beam from the gate to the quasi-ideal beam weight. The output is sent only when the target is located in an angle range where the sensitivity of the quasi-ideal beam becomes flat. When the target is located in another angle range, the output of the Chebyshev weight section becomes smaller than the output of the quasi-ideal beam weight section, and the output of the gate section becomes an output near zero. That is, when the sensitivity is viewed from the output of the gate unit, only the portion where the sensitivity is flat is detected with the flat sensitivity characteristic, and in the portion where the sensitivity is not flat, the sensitivity is set to a value near 0. Become.

[0008]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention.

In the figure, the output of a drive signal source 14 for generating a drive signal for a transducer 11 is given to a quasi-ideal beam weight unit 13, and the output of the quasi-ideal beam weight unit 13 is guided to a trap 12. ing. Further, in the transducer 11 formed by a plurality of electrostrictive vibrators each having an electrode formed on each element, the electrode of each element is bidirectionally connected to the trap 12.

The output from the trap 12 is a buffer amplifier
The light is guided to a quasi-ideal beam weight unit 16 via a line 15, and is introduced to a Chebyshev weight unit 21 via a buffer amplifier 20. The output of the quasi-ideal beam weight unit 16 is sent to the addition circuit 17, and the output of the addition circuit 17 is given to the wide dynamic amplifier 18. The same applies to the output of the Chebyshev weight unit 21, which is guided to a wide dynamic amplifier 23 via an addition circuit 22.

The output of the wide dynamic amplifier 18 is given to one input of a gate signal generating circuit 24 and the input of the A / D converter 19, and the output of the wide dynamic amplifier 23 is the other of the gate signal generating circuit 24. Guided to input. The output of the A / D converter 19 is sent to one input of the gate unit 25 and the image memory 28, and the output of the gate signal generation circuit 24 is given to the other input of the gate unit 25. .

The output of the gate section 25 is sent to a strength memory 26, and the output of the strength memory 26 is given to a data processing section 27. And the display unit 29
, An output from the image memory 28 and an output from the data processing unit 27 are introduced.

In the above configuration, as for the signal line whose connection is indicated by the band, it indicates that the output is constituted by a plurality of signal lines.
The number is equal to the number of elements of the electrostrictive vibrator constituting the transducer 11. Therefore, each of the buffer amplifier 15 and the buffer amplifier 20 is provided with a buffer circuit equal to the number of elements of the transducer 11 in each of them.

The quasi-ideal beam weight section 16 and the Chebyshev weight section 21 are constituted by an amplifier and a resistance attenuator corresponding to each of the signal lines from the respective elements. A configuration is used in which the amplifier operates as an inverting amplifier or a non-inverting amplifier, and the amplitude is attenuated to the amplitude required by a resistance attenuator.

FIG. 2 is an explanatory diagram showing a beam shape formed by one embodiment of the present invention. The operation of one embodiment of the present invention will be described below with reference to FIG.

The drive signal source 14 generates a burst signal and sends it to the quasi-ideal beam weight unit 13. The quasi-ideal beam weight unit 13 to which the burst signal is applied generates a signal of an amplitude level and a phase required for each element of the transducer 11, and sends the generated signal to the trap 12. Trap 12
Transmits this burst signal to the transducer 11,
The burst signal is prevented from leaking to the buffer amplifiers 15 and 20.

As described above, each element of the transducer 11 is given signals of amplitude and phase calculated based on the Bessel function.

The relationship between the amplitude, phase, and frequency of the burst signal applied to each element of the transducer 11 and the shape of each element is not the main point of the present invention. The detailed description is given in Japanese Patent Laid-Open Publication No. Hei 3-23874 and the publication is a known technique, so that the detailed description is omitted to make the main point of the present invention easy to understand.

When the transmitter / receiver 11 in which the burst signals of the required amplitude and phase are given to the respective elements from the quasi-ideal beam weight unit 13 shows the center of the directivity characteristic as an angle 0, the transmitter 31 shown in FIG. As described above, the ultrasonic wave having the directional characteristics of a quasi-ideal beam whose intensity is substantially constant in the angle range d1 and whose intensity is rapidly attenuated on both sides is transmitted into water.

On the other hand, at the time of reception, the ultrasonic wave received by the transducer 11 becomes a signal for each element, and is guided to the buffer amplifiers 15 and 20 via the trap 12. After passing through the buffer amplifier 15, the light is transmitted to the quasi-ideal beam weight unit 16. The quasi-ideal beam weight unit 16 to which the output from the buffer amplifier 15 is guided performs signal processing with a required amplification factor and phase relationship for each signal from each element, and adds the processed signal to an addition circuit 17. To send to.

The adder circuit 17 includes a quasi-ideal beam weight unit 16
The addition is performed on all of the signals for each element processed in the step (1), and the addition result is sent to the wide dynamic amplifier 18. The wide dynamic amplifier 18 corrects the output of the adder circuit 17 for the diffusion and absorption of ultrasonic waves in water, amplifies the output by the set value, and amplifies the output to the A / D converter 19. The signal is sent to the gate signal generation circuit 24. The A / D converter 19 converts the output of the wide dynamic amplifier 18 into a digital value and sends the conversion result to the image memory 28.
The image indicated by the 16 outputs will be displayed.

In the above-described operation at the time of reception, the signal indicating the intensity of the reflected wave received by the transmitter / receiver 11 is weighted by the quasi-ideal beam weight unit 16 and then is subjected to the wide dynamic amplifier 18. , The reception characteristic becomes the quasi-ideal beam characteristic indicated by 31 in FIG. Therefore, the characteristics including the transmission and reception are also quasi-ideal beam characteristics.

The signals from the respective elements guided to the Chebyshev weight section 21 via the buffer amplifier 20 are similarly weighted for giving the Chebyshev characteristic directivity indicated by 32 in FIG. (The weighting method is also a well-known technique, so a detailed description is omitted.) The addition is performed by the addition circuit 22, and the same correction as described above is given by the wide dynamic amplifier 23. Then, the corrected output is sent to the gate signal generation circuit 24.

As a result of the above operation, the relationship between the total characteristic of the quasi-ideal beam (output of the wide dynamic amplifier 18) and the total characteristic of the Chebyshev beam (output of the wide dynamic amplifier 23) given to the gate signal generating circuit 24 is as follows. , FIG. 2
The sensitivity curve of the quasi-ideal beam as shown by 31 and 32
The sensitivity curve of the Chebyshev beam crosses the flat part of the sensitivity of 31.

FIG. 3 is an explanatory diagram showing the beam spread of one embodiment of the present invention in polar coordinates. In FIG. 3, the quasi-ideal beam is indicated by 31a, and the Chebyshev beam is indicated by 32a. I have.

When the output of the Chebyshev weight section 21 (the output of the wide dynamic amplifier 23) is larger than the output of the quasi-ideal beam weight section 16 (the output of the wide dynamic amplifier 18), the gate signal generation circuit 24 outputs the gate signal to the gate section.
25 and no gate signal is generated in the opposite case. The gate unit 25 sends the output of the A / D converter 19 when the gate signal is sent from the gate signal generation circuit 24, and sends out the output value 0 when the gate signal is not sent.

Therefore, if the Chebyshev beam 32 has an object within the angle range d2 in which the sensitivity is higher than the quasi-ideal beam 31 (the position is indicated by 41), the output of the Chebyshev weight unit 21 is quasi-ideal. Since the output is larger than the output of the beam weight section 16, the gate signal is sent from the gate signal generation circuit 24, and the gate section 25 outputs the output of the quasi-ideal beam weight section 16 (the output of the A / D converter 19).
Is output to the strength memory 26.

As the target object, as an angle range d3 (a region where the output of the Chebyshev weight unit 21 is smaller than the output of the quasi-ideal beam weight unit 16), for example, when there is an object at an angle θ1 away from the center of the directivity (42) This object is detected with the sensitivity a1 of the quasi-ideal beam, and the output of the quasi-ideal beam weight unit 16 shows a value smaller than the reflectivity of the actual object. At this time, since the output of the Chebyshev weight unit 21 is smaller than the output of the quasi-ideal beam weight unit 16, the gate signal generation circuit 24 does not send a gate signal.
Therefore, the output of the gate unit 25 has a value of 0.

That is, when the target is located within the angle range d2, the output of the quasi-ideal beam weight unit 16 is sent to the strength memory 26 via the A / D converter 19, and the output of the quasi-ideal beam weight unit 16 falls within the angle range d3. If the target is located, the sensitivity is 0
, The same data as that at the time of is transmitted from the gate unit 25.

This means that the object has a sensitivity for detecting an object only in a region d2 where the sensitivity characteristic of the quasi-ideal beam is almost flat, and the sensitivity suddenly becomes 0 in the other angle range d3. That is, the overall characteristic shows the characteristic as an ideal beam having the characteristic indicated by 33 in FIG.

The data detected by the beam characteristics described above is stored in the strength memory 26. The stored data is processed by the data processing unit 27 and then output from the quasi-ideal beam weight unit 16. Are displayed in a superimposed manner on the display unit 29 for displaying.

It should be noted that the present invention is not limited to the above-described embodiment.
The output of the / D converter 19 and the output of the gate unit 25 can be similarly applied to the case where the subsequent arbitrary processing and display are performed. The output of the converter 19 is given).

Although the transducer 11 has been described as being composed of a plurality of electrostrictive vibrators each having an electrode formed thereon, as another configuration, a plurality of electrodes are formed on one electrostrictive vibrator. The same can be applied to the case of the above-mentioned transducer.

The gate unit 25 has been described as being configured to switch between the output of the wide dynamic amplifier 18 after the A / D conversion and the value 0. A configuration such as an analog switch for switching is possible.

When the output of at least one of the wide dynamic amplifier 18 and the wide dynamic amplifier 23 is made variable and the relationship between the sensitivity curve of the quasi-ideal beam and that of the Chebyshev beam is made variable as shown in FIG. (The sensitivity curve of the Chebyshev beam changes between 32b and 32c), and the sensitivity width as an ideal beam can be changed in the range of d5 to d6.

[0037]

The dual beam ultrasonic detection apparatus according to the present invention transmits an ultrasonic wave having a quasi-ideal beam characteristic at the time of transmission, and weights a quasi-ideal beam characteristic by a quasi-ideal beam weight unit and Chebyshev at the time of reception. Weighting of the Chebyshev beam characteristics by the weight section is performed, and when the output of the Chebyshev weight section becomes larger than the output of the quasi-ideal beam weight section, the output of the quasi-ideal beam weight section is transmitted from the gate section, and in other cases, Is 0
Since the configuration is such that values in the vicinity are output, the level is output only for the target detected in the flat part of the sensitivity characteristic of the quasi-ideal beam, and a value near 0 is transmitted in other angle ranges. . In other words, the overall characteristics are extremely close to the ideal beam characteristics,
The reliability of the obtained data can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a beam shape formed by an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a beam spread in polar coordinates according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state where the relationship between the sensitivity curve of a quasi-ideal beam and that of a Chebyshev beam is made variable.

FIG. 5 is an explanatory diagram showing characteristics of a quasi-ideal beam according to the related art.

[Explanation of symbols]

 11 Transducer 13 Quasi-ideal beam weight section 14 Drive signal source 16 Quasi-ideal beam weight section 21 Chebyshev weight section 25 Gate section 31, 31a Quasi-ideal beams 32, 31a, 31b, 31c Chebyshev beam

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Atsushi Kajiwara 9-52 Ashiharacho, Nishinomiya City Furuno Electric Co., Ltd. In-house (56) References JP-A-3-199991 (JP, A) JP-A-53-129482 ( JP, A) JP-A-52-114361 (JP, A) JP-A-55-58471 (JP, A) JP-A-58-24875 (JP, A) JP-A-61-265132 (JP, A) Hei 4-238499 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S ⁷ /52-7/64 G01S 15/00-15/96

Claims (1)

(57) [Claims] 1. A transmitter / receiver comprising an electrostrictive vibrator having a plurality of electrodes formed thereon, or a transmitter / receiver comprising a plurality of electrostrictive vibrators each having an electrode formed thereon, and driving the transducer. An ultrasonic detection device in which a quasi-ideal beam weight unit for performing weighting so that a beam shape transmitted from the transducer becomes a quasi-ideal beam is inserted between the driving signal source and the electrode, An output is guided, a quasi-ideal beam weight unit that performs weighting such that a reception characteristic becomes a quasi-ideal beam, and a Chebyshev weight unit that performs weighting such that the output of the electrode is guided and the reception characteristic becomes a Chebyshev beam, When the output of the Chebyshev weight section is larger than the output of the quasi-ideal beam weight section, the output of the quasi-ideal beam weight section is sent out.
A dual-beam ultrasonic detection device, comprising: a gate portion that is set to a level near the dual beam ultrasonic detection device.