JP2883679B2 - Ultrasonic reflection intensity measurement device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic reflection intensity measuring apparatus for suitably measuring the TS (reflection intensity) of a single fish, and more particularly, to the TS.
The measuring transducer has a TS measurement beam pattern that has isosensitivity directional characteristics as part of the directivity, and the single fish detection receiver is within the isosensitivity directional characteristics of the TS measurement beam pattern. Form a beam pattern for detecting a single fish having directivity, and when a reflected signal from the single fish is received by the beam pattern for detecting a single fish, the reflection from the single fish received by the TS measurement transducer is used. The signal becomes an ultrasonic signal transmitted and received at the isosensitivity directivity part of the TS measurement beam pattern, and the received signal is measured only for the amplitude value without correcting the directivity of the transducer, and the TS By this, high-precision TS measurement becomes possible, and readjustment of transmission / reception sensitivity is not necessary for each measurement, and further, handling is simplified, and the configuration is simplified, and the device scale is reduced. Ultrasonic reflection intensity measurement To an apparatus.

[Prior Art] Conventionally, a dual beam method shown in FIG. 6 has been known for TS measurement of a single fish.

In this example, a transducer 2 having a known wide-angle radiation characteristic (wide beam pattern b) and a transducer 4 having a narrow-angle radiation characteristic (narrow beam pattern c) are used.

After the ultrasonic wave is radiated from the transducer 2, the single fish i
The angle θ at which the level ratio (V ₁ / V ₂ ) of the received signal of the wide and narrow beams related to the reflected wave deviates from the normal d of the transducers 2 and 4
The TS measurement is performed focusing on the fact that it corresponds to

That is, the levels of the reception signals respectively derived from the transducers 2 and 4 that have received the reflected wave from the single fish i are measured. Then, the level of the received signal is corrected in accordance with the directional characteristics of the wide and narrow beams which are measured in the manufacturing stage and are known in advance. Measurement of TS in single fish i performed by the level ratio of the received signal after the correction (V ₁ / V _2).

[Problems to be Solved by the Invention] However, in the above-described TS measurement according to the related art, the angle θ is detected based on the level ratio (V ₁ / V ₂ ) of the received signals of the wide and narrow beams, and the directional characteristics thereof are detected. , The level fluctuation of the received signal is corrected, so that an error is likely to occur in the TS measurement value under the influence of noise or the like existing in the water. Furthermore, it is necessary to make the total transmission / reception sensitivity including the transmission / reception level for the wide beam and the narrow beam the same, and in this case, it is difficult to keep the transmission / reception sensitivity of the apparatus constant for a long period of time. Therefore, it is necessary to readjust the transmission / reception sensitivity for each measurement, and the handling is complicated. Further, the correction circuit for the level fluctuation of the received signal due to the directional characteristics has a disadvantage that the configuration is relatively complicated, the device scale is increased, and the cost is increased.

The present invention has been made in view of the above points, enables high-accuracy TS measurement, does not require re-adjustment of transmission / reception sensitivity for each measurement, and furthermore, the handling is easy and the configuration is simplified, and It is an object of the present invention to provide an ultrasonic reflection intensity measuring device excellent in scale reduction.

[Means for Solving the Problems] In order to solve the above problems, an ultrasonic reflection intensity measuring apparatus of the present invention includes: a transmitter for generating and outputting a transmission pulse; A TS measurement transducer for transmitting and receiving ultrasonic pulses having isosensitivity directional characteristics as a part of the characteristics, and a directional characteristic narrower than the angle of the isosensitivity directional characteristic, wherein the TS measurement transducer The ultrasonic pulse transmitted from the fish reflected from the fish body, a single fish detection receiver for selectively receiving the signal reflected from the range of equal sensitivity of the TS measurement transducer and A first and a second receiving means for receiving the respective received signals output from the TS measuring transducer and the single fish detecting transducer and outputting respective TVG amplified signals which have been subjected to propagation attenuation correction; A TVG amplifier and an envelope supplied with the respective TVG amplified signals A first and a second detector for outputting a wave signal; a single echo signal detector for detecting a single echo signal from an envelope detection signal from the second detector; A TS measurement echo signal selector for selecting and outputting an echo signal for detecting the value of the reflection intensity from the envelope detection signal from the first detector; and converting an amplitude component of the echo signal into a digital value. An A / D converter that outputs a digital signal; and a TS calculator that corrects an electroacoustic coefficient for the digital signal, calculates and outputs a reflection intensity value of a single target.

[Operation] In the ultrasonic reflection intensity measuring apparatus of the present invention configured as described above, the TS measurement transducer includes a TS measurement beam pattern having isosensitivity directional characteristics in a part of directivity,
Further, in the single fish detection receiver, a single fish detection beam pattern having directivity is formed within the range of the isosensitivity directivity of the TS measurement beam pattern. When the reflected signal from the single fish is received by the single fish detection beam pattern, the reflected signal from the single fish received by the TS measuring transducer is a part of the isosensitivity directional characteristic of the TS measuring beam pattern. The ultrasonic signal is transmitted and received by the above, and the received signal can be obtained only by measuring the amplitude value without correcting the directivity of the transducer.

This allows high-precision TS measurement,
It is not necessary to readjust the transmission / reception sensitivity for each measurement, and further, the handling is easy, the configuration is simplified, and the apparatus scale is reduced.

Embodiment Next, an embodiment of the ultrasonic reflection intensity measuring apparatus of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration according to an embodiment together with a beam pattern, FIG. 2 is a block diagram showing a configuration of a single echo signal detector, and FIG. 3 is a block diagram showing a configuration of a TS measurement echo signal selector. FIG. 4 is a waveform diagram showing a processing waveform relating to a single echo signal detector on a time axis, and FIG.
It is a waveform diagram which shows the processing waveform which concerns on the echo signal selector for a measurement on a time axis.

The example shown in FIG. 1 shows a TS measuring transducer / transmitter / receiver 10 having a radiation characteristic of a TS measuring beam pattern e having equal sensitivity directional characteristics within a range of an angle ±, and a range of the TS measuring beam pattern e. A single fish detection receiver 12 having a single fish detection beam pattern f therein, and a transmitter 14 for outputting a pulse signal
Are provided. Furthermore, it has a first amplifier 16a, a second amplifier 16b, and a first detector 18a and a second detector 18b for performing envelope detection. In addition, a single echo signal detector 20, a TS measurement echo signal selector 22, an A / D converter 24, and a TS calculator 26 are provided.

Here, as shown in FIGS. 2 and 3, the single echo signal detector 20 includes a gate circuit 20a for pulse width selection and a gate circuit 20b for level comparison. The TS measurement echo signal selector 22 is a TS echo signal selection gate circuit 22a.
And a multiplication circuit 22b.

 The operation of the embodiment configured as described above will be described.

 First, the operation according to the basic principle will be described.

As shown in FIG. 1, a single fish detection beam having directivity within the range of a (angle ±) TS measurement beam pattern e having isosensitivity directivity characteristics (h shown in the figure) as a part of the directivity. The accurate TS of the single fish a is measured using f. That is, when the reflected signal from the single fish a is received by the single fish detecting receiver 12 from the single fish a, the reflected signal from the single fish a received by the TS measuring transducer 10 is the same as the TS measuring beam pattern e. This is an ultrasonic signal transmitted and received in the sensitivity directivity portion. Therefore, the TS of the received signal can be obtained by simply measuring the value of the amplitude without correcting the directivity of the transducer 10.

 Next, the operation of the basic principle will be described in detail.

The pulse signal generated by the transmitter 14 is transmitted to the TS
Is input to Here, the ultrasonic pulse radiated into the water from the TS transmitter / receiver 10 is reflected by a single fish a in the water, and
It is received by the transducer 10 for measurement and the receiver 12 for single fish detection.

In this case, the directivity of the TS measurement transducer 10 is an angle ±
Therefore, the reflected wave from the target (single fish a) existing within the iso-sensitivity directional characteristic is received by the TS measurement transducer 10 at the same level.

Output signals Sa and Sb received and received by the TS measurement transducer 10 and the single fish detection transducer 12 are amplified by the first amplifier 16a and the second amplifier 16b, respectively. The first amplifier 16a and the second amplifier 16b perform a well-known TVG control that automatically corrects the propagation attenuation received when the ultrasonic wave propagates in the water. Here, a single fish is targeted, and the TVG control performs, for example, gain control using a value represented by the following equation (1).

TVG = G ₀ +40 log R + 2αR [dB] (1) G ₀ : Minimum gain of first amplifier 16a and second amplifier 16b R: Propagation distance α: Absorption coefficient By performing this TVG control, transmission / reception for TS measurement The level of the reflected signal from the single fish received by the device 10 and the single fish detection receiver 12 does not depend on the depth of the single fish. For this reason, the reflected wave from the single fish that becomes the same TS is received by the TS measurement transducer / receiver 10 and the single fish detection receiver 12, and subsequently, from the first amplifier 16a and the second amplifier 16b. The amplitude values of the derived amplified signals Sc and Sd are equivalent to each other.

Therefore, the amplified signal Sd of the first amplifier 16a has the same T
When the single fish serving as S exists within the iso-sensitivity directivity characteristic within the range of the angle + of the TS measuring transducer 10, the level is the same regardless of the depth and the angle + θ.

On the other hand, the amplified signal Sc output from the second amplifier 16b is at the same level regardless of the depth, but as the angle + θ, that is, as the direction in which the single fish a 'approaches approaches the angle +, the signal for detecting the single fish is used. The level approaches the end of the beam pattern f, and the level rapidly decreases. Then, when the signal exceeds the range of the single fish detection beam pattern f and becomes a single fish a ', the amplified signal Sc cannot be obtained from the second amplifier 16b.

Thus, the first amplifier 16a and the second amplifier 1
The amplified signals Sd and Sc obtained from 6b are output from the first detector 18a, respectively.
Then, the signal is input to the second detector 18b, where envelope detection is performed, and detection signals Sh and Sg are output.

The detection signal Sg shown in FIG. 4 (a) is composed of the signals aN and a'N relating to the illustrated single fishes a and a 'and the fish school echo signal aE.
Is the gate circuit for selecting the pulse width of the single echo signal detector 20
Entered in 20a. Here, the signals are processed by the pulse width selection gate shown in FIG. 4 (b), and the signals aN and a'N relating to the single fishes a and a 'shown in FIG. 4 (c) are extracted and used for level comparison. Input to the gate circuit 20b. Here, a signal aN having a peak level equal to or higher than the level comparison gate (threshold value)
Only is derived. In this way, unnecessary signals related to fish school echoes and seafloor echoes are removed, and a single echo signal is removed.
Only Sj (signal aN) is detected. As described above, the single echo signal Si (signal aN) is detected by processing the detection signal Sg obtained from the second detector 18b with the pulse width being equal to or less than a certain value and the level being equal to or more than a certain value. .

The single echo signal Sj (signal aN) in the detection signal Sg detected by the single echo signal detector 20 is input to the TS echo signal selection gate circuit 22a of the TS measurement echo signal selector 22. Further, the detection signal Sh from the first detector 18a is input to the multiplication circuit 22b of the TS measurement echo signal selector 22. Then, as shown in FIG. 5, the TS measurement echo signal selector 22 outputs the single echo signal Sj and the detection signal
The correlation between the waveforms appearing at the same time from Sh and the detected signal Sh from the first detector 18a whose correlation value is equal to or more than a certain value are converted to T.
Selectively output as S measurement echo signal Sk.

Here, a detailed operation for selecting the TS measurement echo signal Sk will be described.

The signal related to the reflected wave of the single fish a existing within the iso-sensitivity directional characteristic of the angle ± in the TS measurement beam pattern e
And a beam pattern f for detecting a single fish of the single fish a
Let aN be the signal related to the reflected wave.

Furthermore, the TS of the single fish a 'existing outside the isosensitivity directional characteristics
A signal related to the reflected wave of the measurement beam pattern e is denoted by a′W, and a single fish detection beam pattern f of the single fish a ′ is denoted by a′W.
Let a'N be the signal related to the reflected wave.

Here, it is assumed that the single fish a and the single fish a 'are single fish having the same TS, and the depth of the single fish a' is deeper than that of the single fish a.

The detection signal Sh of the first detector 18a shown in FIG.
Has the propagation attenuation corrected, and the amplitude VW of the reflected signal aW from the single fish a has an amplitude corresponding to the TS of the single fish a. On the other hand, the amplitude V 'of the reflected signal a'W from the single fish a'
W is a value smaller than the amplitude VW due to the directivity characteristics (out of the equal sensitivity range) of the TS measurement beam. On the other hand, the second detector 18b
The detection signal Sg has a reflection signal aN (amplitude VN) from the single fish a due to the directivity of the single fish detection beam, but a reflection signal a'N (amplitude V'N) from the single fish a 'V'N is substantially zero or very small even if it exists. Since the single echo signal detector 20 detects a detection signal Sg having a pulse width equal to or less than a certain value and an amplitude equal to or more than a certain value as a single echo signal (Sj), the single echo signal is detected.
As shown in FIG. 5 (a), the echo (signal) and the fish school echo (signal) of the single fish a 'are removed from the detection signal Sg, and Sj becomes only the signal aN of the single fish a.

In the TS measurement echo signal selector 22, the single echo signal Sj of the single echo signal detector 20 and the first detector 18a
If the correlation value between the reflected signal aN and the reflected signal aW is equal to or greater than a predetermined value, the reflected signal aW is output as a signal effective for TS measurement. The reflected signal a'W and the echo from the school of fish do not exist during the period in which the reflected signal aN exists, and are removed. Therefore, echo signal selector for TS measurement
As shown in FIG. 5 (d), only the reflection signal aW received by the TS measurement transducer 10 is output as the TS measurement echo signal Sk of No. 22.

In the TS measurement echo signal Sk selected in this manner, the reflected wave from the single fish a within the equal sensitivity directivity characteristic within the range of the angle ± in FIG. 1 was received by the TS measurement transducer 10. Things. Therefore, signal components related to the reflected wave (echo) from the single fish a 'and the sea floor or the school of fish existing at angles other than ± are removed from the TS measurement echo signal Sk.

Subsequently, the TS measurement echo signal Sk is input to the A / D converter 24, where it is converted into a quantized digital signal. Subsequently, correction of the electroacoustic coefficient is performed by the TS calculator 26, and the single fish a
A TS signal So calculated as the TS value [dB] is output. The calculation of the TS value [dB] in this case is obtained by the following equation (2).

TS = 20log VW−SL−ER−G0 [dB] (2) where, VW: amplitude of TS measurement echo output from A / D converter 24 SL: transmission of TS measurement transducer 10 Level ER: Receiving sensitivity of TS transmitter / receiver 10 G0: Minimum gain of first amplifier 16a and second amplifier 16b In this way, it is not necessary to correct directional characteristics, and
The TS signal So indicating the TS of the single fish a can be accurately measured only by measuring the amplitude of a specific signal among the signals transmitted and received by the TS measuring transducer / transmitter / receiver 10.

[Effects of the Invention] As can be understood from the above description, according to the ultrasonic reflection intensity measuring apparatus of the present invention, it is not necessary to correct the directional characteristics of the transmitter / receiver, and the transmission / reception of the TS measurement transmitter / receiver is simply performed. Since the TS of a single fish is measured simply by measuring the amplitude of a specific signal in the signal to be transmitted, high-precision TS measurement is possible, and it is not necessary to readjust the sensitivity of the character sentence for each measurement. ,further,
There is an effect that the handling is easy, the configuration is simplified, and the device scale is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ultrasonic reflection intensity measuring apparatus according to an embodiment of the present invention together with a beam pattern. FIG. 2 is a block diagram showing a configuration of a single echo signal detector of the embodiment shown in FIG. FIG. 3 is a block diagram showing the configuration of the TS measurement echo signal selector of the embodiment shown in FIG. 1. FIG. 4 is a waveform diagram showing a processing waveform relating to a single echo signal detector on a time axis. FIG. 5 is a waveform diagram showing a processing waveform on a time axis according to a TS measurement echo signal selector, and FIG. 6 is a principle diagram of a dual beam system for performing directional characteristic correction according to a conventional technique. 10 ... TS measurement transducer 12 ... Single fish detection receiver 14 ... Transmitter 16a ... First amplifier 16b ... Second amplifier 18a ... First detector 18b ... Second detector 20 ... Single Echo signal detector 22 ... TS measurement echo signal selector 24 ... A / D converter 26 ... TS calculator a, a '... Single fish e ... TS measurement beam pattern f ... Single fish detection beam pattern

Claims (3)

(57) [Claims] 1. A transmitter for generating and outputting a transmission pulse, and a TS measurement transmission / reception for receiving the transmission pulse and having an equi-sensitivity directional characteristic in a part of the directional characteristic to transmit / receive an ultrasonic pulse. Having a directional characteristic narrower than the angle of the isosensitivity directional characteristic,
The ultrasonic pulse transmitted from the TS measurement transmitter / receiver selectively receives signals reflected from a range of equal sensitivity of the TS measurement transmitter / receiver among signals reflected from a fish body. Each of the received signals output from the fish detection receiver, the TS measurement transmitter / receiver and the single fish detection receiver is supplied, and the respective TVG amplified signals subjected to propagation attenuation correction are output. First and second
TVG amplifier, first and second detectors supplied with the respective TVG amplified signals and outputting an envelope detection signal, and detecting a single echo signal from the envelope detection signal from the second detector A single echo signal detector; a TS measurement echo signal for selecting and outputting an echo signal for detecting a value of a reflection intensity from an envelope detection signal from the first detector during the existence period of the single echo signal A selector, an A / D converter that outputs a digital signal obtained by converting the amplitude component of the echo signal into a digital value, and corrects an electroacoustic coefficient to the digital signal to calculate a reflection intensity value of a single target. An ultrasonic reflection intensity measuring device comprising: 2. The apparatus according to claim 1, wherein the single echo signal detector detects a single echo signal having a fixed pulse width range and a fixed depth range from the envelope detection signal from the second detector. Ultrasonic reflection intensity measuring device comprising a gate circuit for selecting a pulse width and a gate circuit for level comparison. 3. The apparatus according to claim 1, wherein the echo signal selector for TS measurement detects an envelope from the first detector during the existence period of the single echo signal detected by the single echo signal detector. TS echo signal separation for detecting single echo signals with a fixed pulse width, a fixed amplitude, and a fixed depth from a signal, and selecting and outputting echo signals for TS measurement from among them An ultrasonic reflection intensity measuring device, comprising: a gate circuit for use; and a multiplication circuit.