JP4332199B2 - Underwater exploration equipment - Google Patents

Description

  The present invention relates to an apparatus for detecting underwater sound in an apparatus for detecting underwater using ultrasonic waves, using the transmitter / receiver also as a receiver in a non-resonant frequency band.

  2. Description of the Related Art Conventionally, fish finders are known for the purpose of detecting fish schools in water and measuring water depth. This type of fish detector inputs an electric pulse signal repeatedly generated by a transmission unit to an ultrasonic transducer and transmits the ultrasonic pulse into water. The transmitted ultrasonic waves are reflected at the bottom of the water and underwater fish schools and return to the transducer. In the transmitter / receiver, the signal that has been converted into a weak electrical signal again and amplified and detected by the receiver is sampled and stored at a certain time interval from the time of transmission, so that an underwater reflected signal for one transmission can be obtained. It will be obtained in series.

  By arranging the time series signals for each transmission and displaying them on an LCD display, a CRT display, or a recording sheet, a cross-sectional view showing an underwater condition called a B-scope display is displayed. The current mainstream is known as a color fish finder that displays colors on color LCD and CRT displays, making the price cheaper, not only for professional fishing boats, but also for recreational boats. It is popular.

  Some fish produce unique voices and predatory sounds. Therefore, by using both the fish finder and the hydrophone, it is possible to discriminate the fish species that have been relied on by experience and skilled cans. Recently, whale watching is popular as a sightseeing spot, but it is also interesting to listen to whale voices and dolphin conversations, not just watching whales.

  For the purpose of listening to underwater sound, an underwater sound device comprising an underwater microphone, an amplifier, and a speaker is known. This is a device for receiving underwater audible sound with an underwater microphone, amplifying the output signal, and outputting the sound from a speaker for listening. Thus, the combined use of a fish finder and an underwater hearing device can detect a fish school and at the same time identify the fish species of the fish school, leading to the development of the fishery. If you can hear the voices of fish underwater, it will lead to further development of the tourism industry.

  However, the underwater microphone constituting the underwater hearing device is expensive in combination with demand for waterproofness and pressure resistance, and further, there is less demand. For this reason, this type of underwater microphone is conventionally limited to special purposes such as marine life research and military use for submarine detection, and is used for civilian purposes such as fishing boats and recreational boats. Absent. As described above, the underwater sound device is not only expensive, but also has a small equipment space for a small boat such as a leisure boat, so it becomes difficult to use two devices. Accordingly, a first object of the present invention is to realize an underwater exploration device having a hydrophone function with a small and inexpensive configuration.

  In addition, the ship generates noises such as loud engine noise, screw noise and wave noise for propulsion. Under such a loud noise environment, it is extremely difficult to hear faint sounds such as fish calls and predatory sounds. Accordingly, a second object of the present invention is to realize an underwater audible sound listening function capable of listening to a natural weak audible sound even under a large noise environment.

  Furthermore, the voices of whales and dolphins have a higher frequency than human audible sounds, and many pulse sounds. Accordingly, another object of the present invention is to realize a function capable of listening to such a sound.

  The underwater exploration device of the present invention that solves the above-described conventional problems includes an ultrasonic transmitter having an ultrasonic transmitter that transmits ultrasonic waves in water, and a single or a plurality of reflected signals from an object. An ultrasonic exploration unit including an ultrasonic reception unit having a transmission / reception or dedicated ultrasonic receiver, and a display unit that processes a reflected ultrasonic signal received by the ultrasonic reception unit and displays it as a reflection object in water In addition, an audible sound amplifier that amplifies the audible sound signal received by the ultrasonic receiver and an underwater audible sound output means that outputs the amplified audible sound signal acoustically is provided. Yes.

  Further, the underwater exploration device of the present invention includes acoustic analysis means for analyzing the underwater audible sound received by the underwater audible sound listening section, and analysis result display means for displaying the analysis result on the display section, and this analysis. The result display means includes means for displaying the analysis result of the underwater audible sound at a position corresponding to the display position of the reflective object in the water, and the display part of the ultrasonic exploration part detects the appearance of the school of fish and detects the underwater audible sound. An underwater audible sound listening unit / validating means for activating the operation of the listening unit is provided.

  Since the underwater exploration device of the present invention is configured to realize the underwater hearing function by adding a minimum configuration to the fish finder, a simple and inexpensive small underwater sounding device can be realized. As a result, fishermen and anglers of leisure boats can determine the species of fish and enjoy the voices of whales and dolphins for tourists such as whale watching.

  Furthermore, according to the underwater exploration device of the present invention, the underwater audible sound listening unit includes an acoustic analysis unit that analyzes the received underwater audible sound, and an analysis result display unit that displays the analysis result on the display unit. Since the result display means includes means for displaying the analysis result of the underwater audible sound at a position corresponding to the display position of the reflecting object in the water, the fishing boat uses the fish shadow obtained by the ultrasonic radar and the audible sound. This makes it easier and more accurate for fishermen and leisure boat anglers to determine fish species.

According to one preferred embodiment of the present invention, a switch or relay is provided by including selective connection means for selectively connecting the ultrasonic receiver to the ultrasonic exploration section and the underwater audible sound listening section. The fish detection function using ultrasonic waves and the underwater audible sound listening function can be separated using a selective connection means that can be realized with simple and inexpensive parts such as the above. Therefore, in order to realize the underwater audible sound listening function without adding an expensive underwater microphone to the conventional fish finder, the ultrasonic receiver installed for the original fish finder is for underwater audible sound listening. It is also used as an underwater microphone.

  In general, an ultrasonic receiver used in a fish finder is composed of a piezoelectric ceramic element. This type of piezoelectric element has the effect of generating a voltage when a strain is applied by applying stress, and conversely has a function of generating a strain or stress when a voltage is applied. This function is used as a transmitter or receiver in the ultrasonic frequency band. By adding a hydrophone function to a multi-frequency fish finder or sonar having a plurality of transducers using this method, it is possible to measure the position of a fish school in water in three dimensions. Moreover, it can process underwater sound at a high level, and can be useful for research use of aquatic organisms.

  Furthermore, high conversion efficiency is obtained by matching the mechanical resonance frequency of the piezoelectric ceramic element with the frequency band of ultrasonic waves transmitted and received for fish school detection. However, the function of the piezoelectric effect is exhibited at other than the resonance frequency. Even when used as a receiver in the frequency range of underwater audible sound other than the ultrasonic resonance frequency, the conversion efficiency is inferior, but it can be adequately handled by installing an amplifier to compensate for this. Furthermore, since the frequency dependence of the conversion efficiency is small except for the resonance frequency in the ultrasonic band, the receiver has a flat frequency characteristic. This makes it more convenient to receive underwater audible sounds over a wide frequency range.

According to a further preferred embodiment of the present invention, the reflected ultrasonic signal and the audible sound signal received by the ultrasonic receiver are separated from each other by utilizing the difference in frequency between the two, By providing the signal separation means to be supplied to the sound wave exploration section and the underwater audible sound listening section, it is possible to simultaneously realize the fish detection function and the underwater audible sound listening function using ultrasonic waves.

According to another preferred embodiment of the present invention, the audible sound amplifier includes underwater audible sound filtering means for removing various underwater audible sounds received by the ultrasonic receiver as the ship is propelled. Thus, it is configured to remove artificial underwater audible sounds such as engine sound and propulsion device sound accompanying the propulsion of the ship, and to listen to only natural underwater audible sounds.

  According to still another preferred embodiment of the present invention, by adding a means for extending the time axis of the signal and reducing the frequency by digital signal processing, it is higher than the human audible range emitted by dolphins and the like. It is configured to be able to listen to a frequency pulse sound.

  FIG. 1 is a functional block diagram showing the configuration of the underwater exploration apparatus according to the first embodiment of the present invention. The underwater exploration apparatus according to the first embodiment is a one-frequency type fish finder added with a minimum configuration and an underwater hearing sound function. This apparatus includes a timing control circuit 10, a burst signal generation circuit 11, a transmission amplifier circuit 12, a single circuit 13, a transmitter / receiver 14, and a reception amplifier circuit 15 as constituent elements of an ultrasonic exploration unit that realizes a fish detection function. , An A / D converter 16, a B-scope image processing circuit 17, a video converter 18, and an LCD display 19. In addition, this device includes a switching circuit 30, a preamplifier 31a, a filter 32, a main amplifier 33a, a speaker 34, and a filter control circuit 35 as components of the underwater audible sound listening unit.

  The timing control circuit 10 of the ultrasonic exploration unit is composed of an oscillator, and generates a transmission start signal 10a having a period determined by the fish detection range. Assuming, for example, 0 to 100 m (meters) as the detection range of the fish school, a repetition cycle of 133 msec or more is required from the sound speed in water. The timing control circuit 10 adds the post-processing time to this, and repeatedly generates a transmission start signal 10a having a time width of 1 msec with a period of about 200 msec. The burst signal generation circuit 11 includes an oscillator and an amplitude modulator that generate a rectangular wave signal having a frequency (for example, 50 kHz) for fish school detection. The 50 kHz signal is used as a modulated signal and a transmission start signal 10a. Amplitude modulation is performed as a modulation signal, and a 50 kHz toast burst signal having a time width of 1 msec is generated.

  The transmission amplifier circuit 12 is composed of a power amplifier, amplifies the tornast signal supplied from the burst signal generating circuit 11, and generates and outputs a high-voltage tornast signal of 50 kHz, usually about 1000 Vp-p. . The single-row circuit 13 is composed of a diode or the like, and transmits a high-voltage storm signal from the transmission amplifier circuit 12 to the transmitter / receiver 14 via the switching circuit 30, and this high-voltage tuner circuit. Blocking the transmission of the strike signal to the reception amplifier circuit 15 During a time period when there is no high-voltage tornast signal, a weak reception signal of 1 V or less received by the transducer 14 is transmitted only to the reception amplification circuit 15 through the single line circuit 13. With the function of the single line circuit 13, the received signal is transmitted to the transmission amplifier circuit 12 and is efficiently transmitted to the reception amplifier circuit 15 without loss. The switching circuit 30 is composed of a switch and a relay.

  When this apparatus is used for ultrasonic survey for fish school detection, the transducer 14 and the single circuit 13 are connected by a switching operation in the switching circuit 30. When this device is used for listening to underwater audible sound, the transducer 14 and the preamplifier 31 a are connected by a switching operation in the switching circuit 30. The transmitter / receiver 14 is composed of a piezoelectric ceramic element such as barium titanate. When the switch 14 is connected to the single-line circuit 13 by the switching circuit 30, it is driven by a 50 kHz high voltage toast burst signal supplied from the transmission amplifier circuit 12. The Since the resonance frequency of the transmitter / receiver 14 is set in the vicinity of 50 kHz in advance, a large excitation efficiency is realized, and a powerful ultrasonic torn wave is transmitted in water. A part of the transmitted ultrasonic toast burst wave is reflected by a reflecting object such as an underwater school of fish and returned to the transmitter / receiver 14 to be converted into an electrical signal. Then, it is supplied to the reception amplification circuit 15.

  As described above, the transducer 14 performs efficient excitation at the resonance frequency, transmits a strong tornast signal in the water, and the efficiency of the reflected wave from the reflecting object such as a fish school in the water. Reception is performed. At the same time, the transmitter / receiver 14 receives weak audible sound in water, and when connected to the preamplifier 31a through the switching circuit 30, the underwater audible signal is transmitted to the preamplifier 31a.

  The reception amplifier circuit 15 is a narrow-band amplifier having a center frequency of 50 kHz, and amplifies a reflected signal from a reflecting object such as an underwater fish school received by the transducer 14. Usually, it has an amplification factor in the range of 100 to 120 dB, but the amplification factor can be varied with respect to the reflectance of the reflecting object in the water as necessary, as is usually done. The A / D converter 16 classifies the amplitude value of the analog signal output from the reception amplifier circuit 15 into, for example, eight stages and transmits it to the B-scope image processing circuit 17 as a 3-bit digital signal.

  The B-scope image processing circuit 17 includes a memory having a two-dimensional address configuration and a control circuit for accessing and reading the address of the memory. As shown in FIG. 2, the memory having the two-dimensional address configuration includes a memory element accessed by a detection count address and a depth address. The address of this memory corresponds to the number of display pixels of the LCD display 19. For example, the number of detection times of 1 to 640 and the address of 1 to 480 correspond to the number of display pixels of 640 × 480 in the vertical and horizontal directions. With a depth address of. The data length of each memory element is 3 bits corresponding to the number of display colors of the LCD display 19, for example, 8 colors.

  Writing to the two-dimensional address configuration memory is performed as follows. First, in the memory string of the storage position of the detection signal with the oldest detection frequency address, the depth address is determined at a predetermined repetition period from the first address of the depth address, starting from the transmission start signal 10a supplied from the timing control circuit 10. Is incremented by one address, and a 3-bit digital reception signal supplied from the A / D converter 16 is written to the memory element as data. For example, assuming that the detection range of the fish detector is 0 to 100 m and the number of pixels in the depth direction of the LCD display is 480, 100 m is a time of 133 msec from the sound speed in water. 133 ÷ 480 = about 0.277 msec. The writing of the reception signal is stopped when it is performed up to address 480.

  When the writing is stopped, the data in this memory column has stored the latest detection data. Therefore, the storage position of the latest detection signal and the storage position of the oldest detection signal at the detection frequency address. Is shifted one column to the left in FIG. Next, the same writing as described above is continuously performed according to the cycle of the transmission start signal 10a, so that the memory of this two-dimensional address configuration is always reversed for a certain time (transmission cycle × 640) from the present time. In other words, the received reflection signal in the depth range of 100 m from the water surface is stored as a detection signal in eight levels of strength classification.

  An example of a display image of the LCD display 19 is shown in FIG. An example of this display image is the most common B-scope display of a fish finder, and the display screen is composed of 640 × 480 pixels. The vertical pixel row is obtained by displaying the detection signal in the depth range of 0 to 100 m obtained by one transmission by replacing the strength of each detection signal with attributes such as the color and shading of one pixel, The rightmost pixel column displays the latest detection signal, and the leftmost pixel column displays the oldest detection signal. Since it scrolls to the left for each transmission, the detection status in the depth range from the water surface to 100 m underwater for a certain period of time in the past (transmission cycle × 640) is displayed.

  In this display image, a leak signal from the single circuit 13 at the time of transmission and a reflection signal from bubbles or the like existing near the water surface are displayed at the upper end of the image. This is usually called an oscillation line. In addition, a reflected signal from the water bottom is displayed below the display image while changing the water depth. In addition, reflected signals from the school of fish are displayed twice in the water. Each reflected signal is classified into eight stages of amplitude values in the A / D converter 16. As an example, eight colors corresponding to the strength of the reflected signal are added and displayed.

  As understood from the comparison between FIG. 2 and FIG. 3, the content stored in the memory of the two-dimensional address configuration in the B-scope image processing circuit 17 and the image content displayed on the LCD display 19 match. . However, the difference is that in the memory of the two-dimensional configuration, the storage position of the latest detection signal and the storage position of the oldest detection signal are moved one column at a time by the transmission start signal 10a. In the image, the latest detection signal is always displayed at the right end and the oldest detection signal is displayed at the left end.

  Therefore, when reading the memory having the two-dimensional address configuration in the B-scope image processing circuit 17, the following device is required. That is, the memory of the two-dimensional address configuration is read in synchronism with the horizontal and vertical synchronization signals 19a of the LCD display 19, but the detection frequency address that is always read first in the horizontal synchronization signal is the oldest detection signal. The address control is performed so as to start reading from the address of the storage position and sequentially read out to the left in FIG. 2, so that the display screen of the LCD display 19 is scanned and displayed from left to right for each horizontal synchronizing signal. Therefore, the left end is displayed as the oldest detection signal.

  In addition, the depth address is fixed to address 1 at the time of the first horizontal synchronizing signal of the vertical synchronizing signal, and address control is performed so that the address is sequentially increased by the next horizontal synchronizing signal, so that the LCD display On the display screen of the device 19, the upper end is displayed with a depth of 0 m, the depth increases toward the lower end, and the lower end is displayed with a depth of 100 m.

  As described above, the memory having the two-dimensional address configuration is always read out in synchronization with the horizontal / vertical synchronizing signal 19a of the LCD display 19, and the detection signal is displayed on the entire display screen. On the other hand, since the memory having the two-dimensional address configuration is rewritten with the latest detection signal for each transmission start signal 10a, the oldest detection signal at the left end of the display screen disappears and the oldest detection signal is displayed. A new detection signal that is transmitted once more is displayed at the left end, and at the same time, the same display update occurs on the entire display screen, so that the entire image appears to scroll from right to left.

  The video converter 18 includes three D / A converters corresponding to RGB analog inputs of the LCD display 19. Since the storage contents of the two-dimensional address configuration memory in the B-scope image processing circuit 17 are classified for each of the eight amplitude values, the eight steps are RGB distribution corresponding to eight color images, or 8 By converting the analog signal of RGB distribution corresponding to the gradation image at the stage and transmitting it to the LCD display 19, it is possible to cope with arbitrary color display and gradation display.

  Next, the operation of the portion related to the underwater hearing function of the underwater exploration device of the first embodiment will be described. The preamplifier 31a is a low noise amplifier with a high input impedance that amplifies an audible sound band of 20 Hz to 20 kHz. The preamplifier 31a receives and amplifies an underwater audible frequency band signal received by the transducer 14 through the switching circuit 30. The filter circuit 32 includes a plurality of high-pass filters, a plurality of low-pass filters, and a plurality of notch filter circuits. The filter performance specifications such as the center frequency, cutoff frequency, and attenuation amount of each filter are manually changed via the filter control circuit 35, or the frequency of the engine speed signal input to the filter control circuit 35. It is automatically changed according to

  Such various filters are used to remove noise other than the target underwater sound when listening to underwater sound with the underwater exploration apparatus of this embodiment. Here, the underwater noise received when the apparatus of this embodiment is actually installed on a ship and used as a hydrophone is described.

  Since the ship equipped with the underwater exploration device of the first embodiment floats on the water, it is constantly shaken by waves and swells. The water pressure applied to the fluctuates. As a result, a reception signal corresponding to a large noise having a very low frequency corresponding to the fluctuation period is generated in the transducer.

  In addition, the ship has a propulsion device such as an engine for driving and a screw. The engine is composed of a main machine that moves the propeller shaft and an auxiliary machine such as a generator, and the main machine is usually an internal combustion engine. This internal combustion engine generates noise of a specific frequency corresponding to the combustion cycle, but becomes a noise having a relatively wide frequency band in combination with noise of an auxiliary machine and a reduction gear. These broadband noises are radiated into the water through the hull and received by a transducer installed on the bottom of the ship. Further, the propulsion unit itself is like a transmitter, generates noise of a specific frequency corresponding to the number of rotations and the number of blades, and radiates it into the water, which is received by the transmitter / receiver.

  A typical example of such a noise spectrum distribution is as shown in FIG. The spectrum distribution having a width in a very low frequency region is noise generated by the vibration of the ship. Further, the spectrum distribution having a width in the intermediate frequency region is noise generated from a ship engine. Furthermore, noise that is generated from the propulsion device of a ship is present in a line spectrum at a specific frequency, and has several harmonics.

  Noise having such a characteristic spectrum distribution is removed or reduced by a filter. These noises can be removed by adjusting the filter characteristics according to the center frequency of each noise and the spread of the frequency. For example, noise components generated and received due to ship motion are removed or reduced by manually adjusting the filter performance specifications of the high-pass filter of the filter circuit 32 via the filter control circuit 35. Can do.

  Further, noise generated from a ship engine is removed by manually adjusting the filter performance specifications of the high-pass filter and the low-pass filter of the filter circuit 32 via the filter control circuit 35. Can be reduced. Further, since the noise generated from the propulsion device of the ship has harmonics in the frequency band of the line spectrum, the filter performance specifications of the plurality of notch filter circuits are manually operated via the filter control circuit 35. By adjusting with, it can be removed or reduced.

  Further, since the noise generated from the propulsion device is noise having a specific frequency corresponding to the rotation number of the propulsion device and the number of blades, a signal indicating the engine rotation number that is the basis of the rotation number of the propulsion device is sent to the filter control circuit 35. Either by inputting and automatically setting the filter performance specifications of the plurality of notch filter circuits in proportion to the engine rotational speed, it is possible to automatically remove according to various rotational speeds.

  The main amplifier 33a of FIG. 1 is an amplifier that amplifies the power of the audible sound frequency band, and amplifies the audible sound signal in the water and sounds the speaker 34. Of course, a receiver may be used instead of the speaker.

  The above is the description of the configuration and operation of the underwater exploration device according to the first embodiment of the present invention in which the minimum configuration is added to the single-frequency type fish finder to add the underwater hearing sound function. In the apparatus of this embodiment, since the transmitter / receiver is switched and used, the fish finder function and the underwater sound function cannot be realized simultaneously. Therefore, an underwater exploration device that can realize both functions simultaneously will be described below as a second embodiment of the present invention.

  FIG. 5 is a functional block diagram showing the configuration of the underwater exploration device according to the second embodiment of the present invention. As components of the ultrasonic exploration unit for realizing the fish detection function, a timing control circuit 10, a burst signal generation circuit 11, a transmission amplification circuit 12, a single circuit 13, a transducer 14 and a reception similar to those in FIG. An amplifying circuit 15, an A / D converter 16, a B-scope image processing circuit 17, a video converter 18 and an LCD display 19 are provided. Furthermore, a fish school detection circuit 20 that is not included in the apparatus of the first embodiment shown in FIG. 1 is newly added.

  Further, as components of the underwater audible sound listening unit, a filter 32, a speaker 34, and a filter control circuit 35 having the same configuration as in FIG. 1, a preamplifier 31b and a main amplifier 33b having a configuration different from that in FIG. 1 and a newly added separation circuit 36 not included in FIG. In addition, in the underwater exploration apparatus of the second embodiment, the constituent elements having the same reference numerals as those in FIG. 1 are the same as the constituent elements having the corresponding reference numerals in FIG. Is omitted.

  In the underwater exploration device of the second embodiment, the switching circuit 30 installed in the device of FIG. 1 is removed to realize the fish detection function and the underwater audible sound listening function at the same time. The circuit 13 is always connected. A signal obtained by superimposing an underwater audible sound signal on a reflected signal from an underwater fish school or the like received by the transmitter / receiver 14 is supplied to a newly added separation circuit 36 via the single circuit 13. The separating circuit 36 is composed of a bandpass filter having a center frequency of 50 kHz and a lowpass filter having a cutoff frequency of 20 kHz. The reflected ultrasonic signal from the fish school in the water passes through the bandpass filter and is received and amplified by the receiving amplifier circuit 15. Is transmitted to. Also, the underwater audible sound signal passes through the low-pass filter and is transmitted to the preamplifier 31b.

  The preamplifier 31b is composed of a low noise amplifier having a high input impedance for amplifying an audible sound band of 20 Hz to 20 kHz, and receives a signal of an audible sound frequency band in water received by the transmitter / receiver 14 through a separation circuit 36. This is amplified. The signal of the audible sound frequency band to be amplified includes a large-amplitude subharmonic component caused by the high-voltage tornast signal generated by the transmission amplifier circuit 12 periodically with the transmission signal of the fish detector. ing. This unnecessary component leaks into the preamplifier 31b because the separation by the separation circuit 36 is insufficient. If the signal including this unnecessary leakage component is amplified as it is, periodic pulse noise is generated.

  In order to remove this unnecessary leakage component, an analog switch SW as shown in FIG. 6 is installed at the input portion of the low-noise amplifier of the preamplifier 31b. A transmission start signal 10a having a 1 msec time width periodically generated by the timing control circuit 10 is input to the analog switch SW as a switching signal. When the transmission amplifier circuit 12 generates a high-voltage toast burst signal, the input side of the analog switch SW is switched to the ground side by the switching signal, and the subharmonic component is not transmitted as the output signal. Of course, instead of the analog switch SW, it is possible to instantaneously control the bias voltage that determines the operating point of the first-stage amplifier of the preamplifier 31b, thereby removing the unnecessary leakage signal by controlling the amplification factor of the amplifier. .

  The signal of the audible sound frequency band from the preamplifier 31b is transmitted to the main amplifier 33b via the filter circuit 32. Here, the filter circuit 32 and the filter control circuit 35 perform exactly the same functions as those of the apparatus shown in FIG. The main amplifier 33 b is an amplifier that amplifies the power of the audible sound frequency band, where the audible sound signal in water is amplified and supplied to the speaker 34.

  A switch is added inside the main amplifier 33b. A switching signal for this switch is a fish detection signal 20a from a fish detection circuit 20 to be described later, and is a signal that is turned on during the time when the fish detection function detects the fish school. An audible signal amplified only during a period in which this signal is on is supplied to the speaker. While the fish school detection signal 20a is off, the switch is switched so that the amplified audible sound signal is not supplied to the speaker. As a result, when a school of fish is detected, an underwater sound including the voice of the fish is automatically output from the speaker. In this way, the nerves can be concentrated for a long time in order to hear the underwater sound, and it is possible to concentrate on the judgment only when necessary without causing fatigue.

  The fish school detection circuit 20 uses the amplitude value of the detection signal stored in the memory string at the storage position of the latest detection signal in the memory of the two-dimensional address configuration in the B scope imaging processing circuit 17. In this memory column, the latest detection signal is stored in time series as the amplitude value of the detection signal along the depth address, and the amplitude value of the detection signal in the depth address corresponding to the depth range set by manual operation If the amplitude value of the detection signal is larger than the amplitude value of the fish school set by manual setting, the detection signal is determined to be the fish school and the fish detection signal 20a is turned on.

  As described above, in order to realize the fish detection function and the underwater hearing sound function simultaneously, the first and second embodiments of the present invention in which the minimum structure is added to the single frequency type fish detector to realize the underwater sound function. The configuration and operation of the underwater exploration device were explained. The underwater exploration devices according to the first and second embodiments of the present invention each have a configuration using a single-frequency type fish finder. Next, an underwater exploration apparatus according to a third embodiment of the present invention in which a underwater sounding apparatus is realized by adding a minimum configuration to a two-frequency type fish finder will be described.

  FIG. 7 is a functional block diagram showing the configuration of the underwater exploration apparatus according to the third embodiment of the present invention. As a component for realizing the fish detection function, a two-frequency / transmission / reception processing unit 40, a first frequency transducer 41, a second frequency transducer 42, a video converter 18, and an LCD display 19 are installed. ing. In addition, a first audible sound processing unit 43, a first speaker 44, a second audible sound processing unit 45, and a second speaker 46 are installed as components for realizing the underwater hearing sound function. ing.

  The dual frequency / transmission / reception processing unit 40 includes the same burst signal generation circuit 11, transmission amplification circuit 12, single-row circuit 13, reception amplification circuit 15 and the same as those described for the underwater exploration devices of the first and second embodiments. Two transmission / reception systems each including an A / D converter 16 and a B-scope image processing circuit 17 are provided. The two-frequency / transmission / reception processing unit 40 has a function of simultaneously performing transmission at two frequencies, for example, two frequencies of 50 kHz and 200 kHz, in synchronization with the transmission start signal 10 a generated by the timing control circuit 10.

  Then, detection signals such as underwater fish swarms and water bottoms detected by transmitting and receiving ultrasonic waves of each frequency pass through the respective receiving systems and are transmitted to the two-dimensional address configuration memory in the B scope imaging processing circuit 17 for each transmission. The data is written, read out in synchronization with the horizontal / vertical synchronizing signal 19a of the LCD display, and displayed on the LCD display 19 via the video converter 18. At this time, the two-dimensional address configuration memory is divided and used in an area in which the detection frequency address corresponds to two frequencies.

  An example of the display screen by the dual frequency type fish detection function is shown in FIG. The left half of the display screen is a display image of a frequency system of 50 kHz and the right half is 200 kHz. On the display screen, a reflection signal such as a leak from the single circuit 13 at the time of transmission and bubbles near the water surface is displayed at the upper end of each image. Further, a reflected signal of the bottom of the water is displayed below the display image while changing the depth of the water. In addition, a reflection signal of the school of fish is displayed in the water.

  These reflected signals are classified by 8 amplitude values by an A / D converter corresponding to the A / D converter 16 of FIG. 1, and are displayed in eight color images according to the magnitude of the amplitude. However, the display is different between the left and right half of the display image. For example, the reflected signal of the oscillation line or the bottom of the water is displayed shorter in the right 200 kHz system. In addition, in the school of fish (f1 to f3), there is a school of fish (f2) displayed on the left side and not displayed on the right side, the opposite school of fish (f1), and the school of fish (f3) displayed on both sides. The difference depending on the frequency of the fish school display is caused by the fact that the reflectance of the ultrasonic wave due to the body length of the fish differs depending on the frequency. By utilizing the difference on the display screen, it is possible to estimate the body length of the fish, which is an advantage of using a two-frequency fish finder.

  The first transducer 41 is a transducer composed of a piezoelectric ceramic element having a resonance frequency of 200 kHz, and the second transducer 42 is a resonance frequency of 50 kHz. The transducers 41 and 42 perform transmission and reception of ultrasonic waves in water at each frequency, but also receive audible sounds in water at the same time. The audible sound signals from the transducers 41 and 42 pass through the circuits corresponding to the switching circuit 30 and the separation circuit 36 described in relation to the devices of the first and second embodiments in the dual frequency / transmission / reception processing unit 40. It is transmitted to the first audible sound processing unit 43 and the second audible sound processing unit 45.

  The first audible sound processing unit 43 and the second audible sound processing unit 45 are composed of the preamplifier 31, the filter 32, the main amplifier 33, the filter control circuit 35, and the like described in the apparatuses of the first and second embodiments. The Then, the first audible sound processing unit 43 performs filtering and amplification in the frequency domain on the underwater audible sound signal received by the first transducer 41, and the first speaker 44. Can be sounded. Similarly, the second audible sound processing unit 45 performs filtering and amplification in the frequency domain on the underwater audible sound signal received by the second transmitter / receiver 42, and the second speaker 46 It is made to ring.

  By listening to the audible sound from the first speaker 44 and the second speaker 46 with the left and right ears, not only the audible sound in the water but also the first transducer 41 and By devising the installation position of the second transducer 42, the direction of the underwater sound source can also be estimated by the stereo effect.

  The above is the configuration and operation of the underwater exploration apparatus according to the third embodiment that realizes the underwater hearing function by adding a minimum configuration to the dual-frequency fish finder. Furthermore, by applying the underwater exploration apparatus according to the third embodiment, underwater sound is heard using a large number of transducers possessed by a multi-frequency type fish finder, sonar, etc. Dimensional measurement is also possible.

  In the said 3rd Example, the case of the 2 frequency type fish finder which transmits / receives two types of ultrasonic waves of a different ultrasonic frequency was illustrated. However, in order to transmit and receive ultrasonic waves of the same frequency and detect the azimuth angle of the reflecting object from the arrangement of the plurality of receiving elements and the phase difference of the reception signals of each receiving element, the position where the plurality of receiving elements are installed is used. It is of course possible to apply the present embodiment to a phase difference detection type ultrasonic survey apparatus.

  The embodiments so far are examples in which the underwater audible sound listening function is realized by adding the minimum components to the configuration necessary for realizing the fish finder function. Next, the configuration and operation of the underwater exploration apparatus according to the fourth embodiment in which the underwater audible sound listening function is advanced will be described.

  FIG. 9 is a functional block diagram showing the configuration of the underwater exploration apparatus according to the fourth embodiment of the present invention. A transmission / reception processor 50, a transmitter / receiver 51, a video converter 18 and an LCD display 19 are installed as components of the ultrasonic probe that realizes the fish detection function. In addition, an audible sound processing unit 53 and a speaker 54 are installed as components of the underwater audible sound listening unit. Further, as components for realizing the advanced functions of the underwater audible sound listening unit, a personal computer 60, an A / D converter 61, a D / A converter 62, a super impose circuit 63 and a display. An area generation circuit 64 is provided.

  The transmission / reception processing unit 50 includes the timing control circuit 10, the burst signal generation circuit 11, the transmission amplification circuit 12, the single row circuit 13, the reception amplification circuit 15, and the A / D converter 16 described in the first and second embodiments. And a B-scope imaging processing circuit 17 is incorporated. An ultrasonic signal is transmitted in synchronization with a transmission start signal 10a generated by the timing control circuit 10, and a reflected ultrasonic signal from a fish school or the bottom of the water is received as a detection signal. Is written in the memory of the two-dimensional address configuration in the processing circuit 17. The detection signal written in the memory is read out in synchronization with the horizontal / vertical synchronizing signal 19a of the LCD display, passed through the video converter 18 and the superimpose circuit 63, and then the LCD display 19. Is displayed.

  The transducer 51 is composed of a piezoelectric ceramic element having a resonance frequency of 50 kHz, and transmits an ultrasonic signal having a frequency in the vicinity of the resonance point into the water, and receives a reflected wave from the water. The transducer 51 also receives underwater audible sounds. The audible sound signal received by the transducer 51 is transmitted to the audible sound processing unit 53 through the switching circuit 30 and the separation circuit 36 described in the first and second embodiments in the transmission / reception processing unit 50. The audible sound processing unit 53 includes the preamplifier 31, the filter 32, the main amplifier 33, the filter control circuit 35, and the like described in the first and second embodiments. In the audible sound processing unit 53, the underwater audible sound signal received by the transducer 51 is filtered and amplified in the frequency domain to cause the speaker 54 to ring.

  The configuration for adding the underwater audible sound listening function to the ultrasonic sounding unit for realizing the fish school detecting function in the underwater sounding apparatus according to the fourth embodiment of the present invention has been described above. Next, the part related to the advancement of the characteristic underwater audible sound listening function in the fourth embodiment will be described in detail.

  The personal computer 60 includes an A / D converter 61 and a D / A converter 62 at the input interface and the output interface, respectively, and the underwater audible sound signal received by the transducer 51 is transmitted to the transmission / reception processing unit 50 and the A / A. A digital signal is taken in via the D converter 61. The personal computer 60 performs various kinds of signal processing by software on the digital signal, and the result is again converted into an analog signal by the D / A converter 62 to cause the speaker 54 to ring. In addition, the result of various digital signal processing by software is converted into a graphic display image by characters / graphics and output as a graphic video signal 60a.

  The superimpose circuit 63 is composed of a switch for the video signal, and the fish finder video signal 18a supplied from the video converter 18 according to the polarity of the display area signal 64a generated by the display area generating circuit 64. Then, one of the graphic video signals 60 a supplied from the personal computer 60 is selected and supplied to the LCD display 19.

  The display area generation circuit 64 counts the synchronization signal 19a and determines the display area of the LCD display 19 based on the number of counts. For example, if the number of display pixels of the LCD display is 480 vertical × horizontal 640, the horizontal sync signal is counted 240 times to switch the display area in order to divide the display area into upper and lower equal parts. Further, in order to divide the display area equally in the left and right directions, the time when the pixel clock is counted 320 times in each horizontal synchronization signal is the time when the display area is switched. In this example, the upper and lower or left and right half are divided, but it goes without saying that the display area can be switched to an arbitrary display area by changing the number of counts.

  Using the configuration as described above, the signal received by the transmitter / receiver 51 is captured as a digital signal, and the result of digital signal processing by software in the personal computer 60 is displayed on the LCD display 19 as a graphic display image using characters and figures. An example of the displayed image is shown in FIG. In FIG. 10, the upper half image is an underwater fish detection (ultrasonic exploration) image at 50 kHz, and the lower half is a graph showing the result of frequency analysis of the current underwater audible sound by Fourier transform of digital processing. Show. While viewing this graph display, the above-described filter control circuit 35 can be manually operated, and unnecessary underwater noise such as engine rotation noise can be quickly removed.

  In FIG. 11, the upper half image is an underwater fish finder image at 50 kHz. In the lower half, the audible sound is subjected to frequency analysis, and the result is displayed with time on the horizontal axis, frequency on the vertical axis, and signal strength in line thickness, shading, or color. It is an expression method similar to the sound analysis sonograph. By doing so, the analysis result moves in synchronization with the upper half fish detection image, and the upper half fish school image and the lower half analysis result are displayed at corresponding positions, thereby facilitating fish type discrimination. Needless to say, by changing the signal processing software, a variety of signal analysis results can be displayed together with the fish detection video.

  Next, an audible sound signal received by the transmitter / receiver 51 is taken in as a digital signal, digital signal processing by software is performed by the personal computer 60, and the result is converted to an analog signal again, and the example of the waveform when the speaker 54 is sounded. Is shown in FIG. In FIG. 12, the original sound was a 1 msec pulse sound. This is written into a memory string in the personal computer 60, and then is subjected to digital signal processing by software that is read out at a cycle 1000 times as long as the write cycle, thereby producing an extended sound with a time width of 1 second. By performing such a time axis extension process, it becomes possible to grasp the characteristics of the pulse sound that cannot be discriminated normally even by hearing.

  Note that by changing the digital signal processing software, it is possible to change the frequency of an underwater signal to an audible sound region and listen to it.

It has been described a fourth embodiment of the configuration and operation with a high degree of hydrophone function. In this embodiment, the digital signal processing is performed by a general-purpose personal computer, but it is needless to say that it may be realized by a dedicated hardware configuration. In particular, the current fish finder displays the detection signal, and also displays the scale display of the detection range, the numerical value display of the water depth value, and the graph display superimposed on the detection signal. This is possible by using the graphic display function and the control function added to.

  In the above, the structure which installs the ultrasonic transducer shared for transmission / reception was illustrated. However, it is also possible to employ a configuration in which a transmission-dedicated transducer and one or a plurality of reception-dedicated transducers are individually installed, and the underwater audible sound received by the reception-dedicated ultrasonic transducer is processed and listened to.

It is a functional block diagram showing composition of an underwater exploration device concerning the 1st example of the present invention. FIG. 2 is a conceptual diagram for explaining the configuration and operation of a memory having a two-dimensional address configuration in the B-scope imaging processing circuit 18 of FIG. 1. It is a conceptual diagram which shows an example of the display image of the 1 frequency type fish finder displayed on the LCD display 19 of FIG. It is a frequency characteristic figure which shows a typical example of the frequency distribution of the underwater noise received by the transducer 14 of FIG. It is a functional block diagram which shows the structure of the underwater exploration apparatus concerning the 2nd Example of this invention. FIG. 6 is a functional block diagram showing a configuration of a reception signal selector switch SW installed in the preamplifier 31b in FIG. 5; It is a functional block diagram which shows the structure of the underwater exploration apparatus concerning the 3rd Example of this invention. It is a conceptual diagram which shows an example of the display screen of the 2 frequency type fish finder displayed on the LCD display 19 of the said FIG. It is a functional block diagram which shows the structure of the underwater exploration apparatus concerning the 4th Example of this invention. FIG. 10 is a conceptual diagram illustrating an example of a superimposed image displayed on the LCD display 19 in FIG. 9. FIG. 10 is a conceptual diagram illustrating another example of a superimposed image displayed on the LCD display 19 in FIG. 9. FIG. 10 is a waveform diagram showing an example of a waveform of a pulse sound whose time axis is expanded by digital signal processing by the personal computer 60 in FIG. 9.

Explanation of symbols

10 Timing control circuit
11 Burst signal generator
12 Transmission amplifier circuit
13 Single circuit
14 Transceiver
15 Receive amplifier circuit
16 A / D converter
17 B-scope image processing circuit
18 Video converter
19 LCD display
20 Fish detection circuit
30 switching circuit
31a, 31b preamplifier
32 filters
33a, 33b Main amplifier
34 Speaker
35 Filter control circuit
36 Separation circuit
40 Dual frequency transmission / reception processor
41,42 First and second transducers
43,45 1st and 2nd audible sound processor
44,46 First and second speakers
50 Transmission / reception processor
51 Transceiver
53 Audible sound processor
54 Speaker
60 PC
61 A / D converter
62 D / A converter
63 Spur Impose Circuit
64 Display area generator

Claims (9)

Ultrasonic transmitter having an ultrasonic transmitter for transmitting ultrasonic waves in water and an ultrasonic receiver having a single or plural ultrasonic receivers for transmission / reception for receiving reflected signals from an object. Unit, a display unit that processes the reflected ultrasonic signal received by the ultrasonic receiving unit and displays it as an underwater reflecting object, and the amplitude value of the reflected ultrasonic signal and the fish school amplitude value set to a predetermined value An ultrasonic exploration unit including a fish detection circuit that outputs a fish detection signal if the amplitude value of the reflected ultrasonic signal is large ,
A single or a plurality of audible sound amplifiers for amplifying the audible sound signal received by the single or a plurality of ultrasonic receivers, and a single or a plurality of audible sound signals for outputting the amplified single or a plurality of audible sound signals. An underwater audible sound listening section including a plurality of audible sound output means ;
The underwater audible part listening unit includes an acoustic analysis unit that analyzes the received underwater audible sound, and an analysis result display unit that displays the analysis result on a display unit;
The analysis result display means includes means for displaying the analysis result of the underwater audible sound at a different position corresponding to the display position of the reflecting object in water, and the display unit of the ultrasonic exploration unit includes the fish school detection circuit. An underwater exploration apparatus comprising: an underwater audible sound listening unit / validating unit that validates the operation of the audible sound output means based on a fish school detection signal output from, and outputs the underwater audible sound . In claim 1,
The underwater exploration apparatus, wherein the acoustic analysis means includes means for Fourier-transforming the received underwater audible sound to create a frequency spectrum. In either one of claims 1 or 2,
An underwater exploration apparatus comprising a selective connection means for selectively connecting the single or plural ultrasonic receivers to the ultrasonic exploration unit and the underwater audible sound listening unit. In any one of Claim 1 or 2,
The reflected ultrasonic signal and the audible sound signal received by the single or plural ultrasonic receivers are separated from each other by using the difference in frequency between the two, and each is separated from the ultrasonic exploration unit and the underwater audible sound. An underwater exploration device comprising signal separation means for supplying to a listening unit. In any one of Claims 1 thru | or 3,
An underwater exploration apparatus further comprising an amplification function / invalidating unit that invalidates a function of the audible sound amplifier in synchronization with a transmission timing signal supplied from the ultrasonic transmission unit. In any one of Claims 1 thru | or 5,
The underwater exploration apparatus, wherein the audible sound amplifier includes underwater audible sound filtering means for removing various underwater audible sounds received by the ultrasonic wave receiver as a ship is propelled. In claim 6,
An underwater exploration device comprising means for changing the filtering characteristics of the underwater audible sound filtering means according to a manual operation. In any one of Claim 6 or 7,
An underwater exploration apparatus comprising means for automatically changing the filtering characteristics of the underwater audible sound filtering means according to the engine speed of a ship. In any one of Claims 1 to 8,
The underwater audible sound listening section comprises an audible sound generating means for making an inaudible sound in water audible by extending a time axis based on digital processing and outputting the audible sound from the audible sound output means. .