Measuring equipment

Abstract

To improve the measurement efficiency.SOLUTION: A measurement device 100 has a low-frequency sampling part 2 which detects the surrounding environment in water by sampling about once per second, a control part 1 which determines whether to detect the sound in the water according to the detection result of the low-frequency sampling part 2, and a high-frequency sampling part 4 which detects the sound in the water at a frequency higher than the sampling frequency of the low-frequency sampling part 2 when the control part 1 determined to detect the sound in the water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measurement device. [Background technology]

[0002] Many marine organisms are acoustically sensitive and use sounds extensively, for example, for underwater exploration, communication, threats, and reproduction.

[0003] In water, sound travels incomparably farther than light. The speed of sound in air is about 330 meters per second, but in water it travels roughly 4.5 times faster, at about 1,500 meters per second. Although it is much slower than light, sound travels farther and its effects are immediate.

[0004] In recent years, there have been many reports of the effects of sound exposure on living organisms. There are various artificial sound sources in the ocean, the most common of which are ships. It has been pointed out that the sounds emitted by ships due to maritime traffic may be shortening the distance over which whales and fish can communicate, and in some cases affecting their reproduction.

[0005] On the other hand, there is also naturally occurring noise in the ocean. Natural sounds include wind, rain, waves, currents, and volcanic sounds. Weather and sea conditions also produce underwater sounds. Broadband sounds caused by rain are radiated from the ocean surface into the sea. Broadband sounds are also generated by bubbles generated by breaking waves in stormy weather.

[0006] Furthermore, biological sounds include not only sounds made by living things (fish, cetaceans, etc.), but also all sounds associated with the behavior and movement of living things, such as chewing sounds and the swimming sounds of schools of fish. For example, there is the pulse sound made by pistol shrimps that are constantly emitted from coastal areas. Artificial sounds include those generated by ships, piling, air guns, offshore wind turbines, sonar, and divers. As described above, underwater sounds consist of artificial sounds, natural sounds, and biological sounds, and by monitoring underwater sounds, it is possible to collect a variety of information originating from various sound sources.

[0007] Until now, underwater sound monitoring has been performed by hanging underwater microphones from ships to observe underwater sounds, or by using surface-based (buoy) or underwater-based recorders. Sound has also been observed by moving objects such as ocean gliders. However, ocean gliders are difficult to use in shallow waters. Observations from ships are difficult to carry out over long periods of time or over a wide area due to the cost and effort involved. Surface-based (buoy) and underwater-based recorders are often difficult to implement in coastal areas due to maritime security reasons, such as requiring special installation permits or limiting installation locations.

[0008] Biologging and biotelemetry are well-known techniques for measuring the behavior, physiology, and environmental experiences of wildlife, in which measurement devices equipped with various sensors are attached directly to the living body.

[0009] Here, biologging refers to, for example, recording measured data inside a measurement device, while biotelemetry refers to, for example, transmitting measured data outside the measurement device via wireless or other means and remotely collecting the measured data (in a broad sense, biotelemetry is also included in biologging).

[0010] The measuring device used for biologging includes, for example, a battery, an electronic board equipped with sensors, memory, wireless terminals, etc., and a housing (a case made of resin, metal, etc., or something with equivalent performance) that covers these.

[0011] Biologging can also be used to observe underwater sounds. For example, by equipping marine organisms such as sea turtles and seals with underwater sound recorders, it becomes possible to monitor underwater sounds as autonomous mobile bodies. Furthermore, because some marine organisms, such as sea turtles and seals, periodically surface to breathe, it is possible to obtain their location using radio waves from satellites (GNSS, Argos satellites, Iridium satellites, etc.), as well as transmit data via satellite communications or short-range radio. With biologging, there is no need to install equipment underwater or on the surface, so it is thought that underwater sounds can be observed over a wide area, even in coastal areas. [Prior art documents] [Non-patent literature]

[0012] [Non-Patent Document 1] "Biologging" [online] May 2019: First edition published, National Institute for Environmental Studies, National Research and Development Agency [Retrieved July 13, 2021], Internet<URL:https: / / tenbou.nies.go.jp / science / description / detail.php?id=109> Summary of the Invention [Problem to be solved by the invention]

[0013] In this way, observing underwater acoustics through biologging is considered an effective method for observing underwater artificial sounds, environmental sounds, and biological sounds. However, unless the underwater sound data has a quality that is suitable for analysis, the data will be meaningless even if recorded in the first place. Furthermore, because biologging places a burden on the organism by attaching equipment to it, it is preferable to keep the size of the equipment attached to the organism as small as possible. In one aspect, the present invention aims to improve the efficiency of observation. [Means for solving the problem]

[0014] To achieve the above object, the disclosed measuring device includes a first detection unit that detects the surrounding environment and the behavior of an individual wearing the measuring device underwater at a first frequency, a determination unit that determines whether or not underwater sound is detected based on the detection result of the first detection unit, and a second detection unit that measures and detects underwater sound at a frequency higher than the first frequency when the determination unit determines that underwater sound has been detected. [Effects of the Invention]

[0015] In one aspect, the efficiency of observation can be improved. This is because, instead of observing underwater sounds continuously, the period of time that is preferable for actual observation can be narrowed down, which reduces the power required for observation and encourages the use of smaller batteries. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating a measurement device according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating the functions of the measurement device according to the embodiment. [Figure 3] 10 is a flowchart illustrating the operation of the measurement device. [Figure 4] FIG. 1 shows an example of depth data obtained from a sea turtle. [Figure 5] FIG. 2 illustrates an example of a hardware configuration of a measurement apparatus according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a measuring device according to an embodiment will be described in detail with reference to the drawings.

[0018] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the following drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings, etc. In the embodiments, elements expressed in the singular include the plural unless otherwise clearly indicated in the context. <Embodiment> FIG. 1 is a diagram showing a measurement device according to an embodiment. 1 is attached directly to, for example, a living body. The living body is not particularly limited, but examples thereof include fish, reptiles that live in water, and mammals.

[0019] For example, there are two methods for attaching the measurement device 100 to fish: internal attachment, in which the measurement device 100 is inserted into the abdominal cavity of the fish, and external attachment, in which the measurement device 100 is attached to the surface of the fish's body. External attachment may involve passing metal wire, fishing line, cable ties, etc. through the body during attachment. External attachment is generally not suitable for long-term attachment in many cases, as it increases fluid resistance and can cause wounds at the attachment site to become infected. For this reason, it is generally believed that internal attachment is often more suitable for long-term attachment in fish. FIG. 2 is a block diagram illustrating the functions of the measurement device according to the embodiment.

[0020] The measuring device 100 comprises a control unit 1, a low-frequency sampling unit 2, an underwater microphone 3, a high-frequency sampling unit 4, a memory 5, a data processing unit 6, and a data transmission unit . The control unit 1 controls the entire measuring device 100 .

[0021] The low-frequency sampling unit 2 has a plurality of sensors. These sensors perform sampling at, for example, a few Hz to a few tens of Hz (for example, about once per second). The low-frequency sampling unit 2 has an environment sensor unit 21 and a behavior sensor unit 22.

[0022] The environmental sensor unit 21 collects data related to the environment of the living organism. Specifically, the environmental sensor unit 21 has a temperature sensor 211, a salinity sensor 212, a dissolved oxygen sensor 213, and an illuminance sensor 214. The sensors included in the environmental sensor unit 21 are not particularly limited, and examples thereof include a chlorophyll sensor, a turbidity sensor, a pH sensor, an alkali sensor, and the like that can measure the environment in addition to the above. The temperature sensor 211 detects the temperature of the water in which the measurement device 100 is located. The salinity sensor 212 detects the salinity in the water in which the measurement device 100 is located. The dissolved oxygen sensor 213 detects the amount of dissolved oxygen in the water in which the measurement device 100 is located. The illuminance sensor 214 detects the illuminance in the water in which the measurement device 100 is located.

[0023] The behavior sensor unit 22 collects data on the behavior of a living organism. Specifically, the behavior sensor unit 21 has a speed sensor 221, an acceleration sensor 222, a depth sensor 223, a gyro sensor 224, and a geomagnetic sensor 225. The sensors included in the behavior sensor unit 22 are not particularly limited, and examples thereof include an ultrasonic oscillator capable of estimating a position, a depth finder, and an illuminance sensor in addition to the above. The speed sensor 221 detects the speed of the living body. The acceleration sensor 222 detects the acceleration of the living body. The depth sensor 223 detects the depth at which the living body is located. The gyro sensor 224 detects the rotation and change in orientation of the living body as angular velocity. The geomagnetic sensor 225 detects the geomagnetism at the location where the living body is located.

[0024] The sensors included in the environment sensor unit 21 and the behavior sensor unit 22 described above may be divided arbitrarily. The environment sensor unit 21 and the behavior sensor unit 22 may each have separate sensors. Some sensors may be omitted. The underwater microphone 3 is used when the low frequency sampling unit 2 and the high frequency sampling unit 4 sample underwater sounds (artificial sounds, environmental sounds, biological sounds).

[0025] The high-frequency sampling unit 4 samples underwater sounds to be observed. These sounds are composed of sound waves in the frequency band from several Hz to several hundred kHz. For this reason, the high-frequency sampling unit 4 performs sampling at a higher frequency (for example, several tens of kHz to several hundreds of kHz) than the low-frequency sampling unit 2. The data obtained by sampling (sound collection data) is stored in memory 5.

[0026] The data processing unit 6 reads the collected sound data sampled by the high-frequency sampling unit 4 from the memory 5 and performs so-called edge processing. Examples of edge processing include noise processing such as moving average filters and median filters, statistical processing that extracts statistical values ​​(average, effective value, maximum, minimum), and frequency analysis processing such as fast Fourier transform. Other examples include voice detection and classification using models such as machine learning and deep learning. By performing edge processing, the amount and time of data transmission can be reduced. The data transmission unit 7 transmits the data processed by the data processing unit 6 to, for example, a satellite, a base station, etc. The transmitted data is stored in a cloud server, etc. The data processing unit 6 and the data transmission unit 7 can also be disposed outside the measurement device 100. Next, an example of the operation of the measuring device 100 will be described. FIG. 3 is a flowchart illustrating the operation of the measurement device. The measuring device 100 executes the following process each time the low-frequency sampling unit 2 performs sampling. [Step S1] The control unit 1 performs sampling using each sensor included in the low-frequency sampling unit 2, and obtains the detection results.

[0027] [Step S2] Based on the detection results of each sensor, the control unit 1 determines whether or not to perform sampling in the high-frequency sampling unit 4. Specifically, based on the detection results of each sensor, the control unit 1 determines some or all of the following: (a) environmental conditions, (b) depth, (c) horizontal position, (d) the movement state of the logger, (e) date and time, and (f) sound pressure, background noise level, etc.

[0028] (a) Environmental conditions are calculated based on the detection results of the temperature sensor 221, salinity sensor 212, dissolved oxygen sensor 213, and illuminance sensor 214. (b) Depth is calculated based on the detection results of the depth sensor 223. (c) Horizontal position is calculated by comparing the current position with environmental conditions such as radio waves from satellites (e.g., GNSS: Global Navigation Satellite System, Argos satellite, Iridium satellite) and short-range wireless (LPWA: Low Power Wide Area), the time difference between ultrasonic waves and multiple receivers and transmitters, inertial navigation (consisting of speed, acceleration, gyro, geomagnetism, depth sensor, etc.), tides, and illuminance, and by comparing the calculated position with a bathymetric map and a marine life habitat map stored in advance in memory 5 to determine whether the conditions are met. (d) The logger's motion state is calculated based on the detection results of the acceleration sensor 222, gyro sensor 224, geomagnetic sensor 225, speed sensor 221, depth sensor 223, etc. (e) The date and time are obtained from the RTC (Real-Time Clock) inside the logger. (f) The sound pressure and background noise level are calculated based on the results of sampling by the low-frequency sampling unit 2 using the underwater microphone 3. The conditions for the combinations of (a) to (f) and their priorities are stored in advance in the memory 5 according to the sensor configuration of the low-frequency sampling of the device and the purpose of recording.

[0029] For example, if the goal is to detect and classify all underwater sounds (without targeting specific sounds), the only conditions that can be used are the depth, which is suitable for observing underwater sounds and has little effect from water surface reflection, and the movement state of the logger, which has little effect from noise.On the other hand, if the target is a specific sound, additional conditions can be the time of day when the target sound is expected to occur (for example, nighttime if the target is the sounds of nocturnal organisms or activity sounds, or daytime if the target is artificial sounds from underwater construction), horizontal and vertical position (for example, an area where the target organism is expected to exist or an area where the impact of artificial sounds is desired to be evaluated), and even the environment (environmental conditions where the target still life is expected to exist).For specific examples of each condition, see Examples 1-5 below.

[0030] Based on these results of calculation, the control unit 1 determines whether or not to perform sampling in the high frequency sampling unit 4. The criteria for this determination are not particularly limited, but the following examples can be given.

[0031] (Example 1) When the depth at which the living organism is located is within a certain range (for example, a depth at least one wavelength greater than the target sound: since the wavelength of a 200 Hz sound wave is 7.5 m, it is 7.5 m or deeper from the water surface), the control unit 1 determines to perform underwater sound sampling. Marine organisms move in various ways from the surface to the seafloor (this varies depending on the species, season, time, etc.). On the other hand, underwater sounds cannot exist in principle just below the water surface due to reflections from the surface. For this reason, when using marine organisms to observe underwater sounds in the environment, even if measurements are taken near the water surface, it is difficult to obtain high-quality measurements of underwater sounds, which consist of artificial sounds, environmental sounds, and biological sounds (excluding sounds such as breathing, which are sounds made at the surface by the organism wearing the device).

[0032] Furthermore, down to depths of several wavelengths, the underwater microphone 3 is affected by out-of-phase reflections from the water surface. Therefore, if sound pressure is measured while submerging the underwater microphone 3 at the same distance from the sound source, the received sound pressure will fluctuate depending on the water depth. Another reflector in underwater acoustic propagation is the seafloor. Because the seafloor is solid, phase inversion of the reflected wave does not occur, as it does at the water surface, and it is not a perfect reflector like the water surface. Sound waves are absorbed, and depending on the geological structure, sound waves that enter the submarine may be reflected at the boundary and return. In shallow waters, the underwater microphone 3 is affected by both surface and bottom reflections, so it is desirable to install the underwater microphone 3 as far away as possible from both. While the distance from the water surface can be determined by measuring the depth with a pressure sensor, the distance from the seafloor can be determined by ultrasonic sounding or by comparing the horizontal position with a bathymetric map.

[0033] As mentioned above, marine organisms move in various ways from the surface to the seafloor, but if it is possible to determine whether to record underwater sounds based on the depth at which they are observed, it will be possible to observe underwater sounds at the appropriate time (when meaningful data can be obtained), thereby reducing power consumption. For reference, an example of depth data obtained from a sea turtle is shown in Figure 4.

[0034] (Example 2) Furthermore, flow noise may occur when the marine organisms are swimming. Whether the marine organisms are moving or resting can be determined by using the acceleration sensor 222 (several Hz to several tens of Hz) and the depth sensor 223.

[0035] This can be determined from the value of the acceleration and depth change per unit time (at most once per second). Therefore, if the change in acceleration or depth per unit time is below a certain value, it is determined that the marine organism is resting, and the control unit 1 will decide to perform sampling of underwater sounds. This makes it possible to reduce flow noise in the collected sound data.

[0036] (Example 3) Pulse sounds from pistol shrimp and other creatures are generated in coastal areas, but are not observed offshore to a certain extent. For this reason, if underwater sound observation in coastal areas is not the target, the control unit 1 determines whether the living organism wearing the measuring device 100 has moved offshore, and if it determines that the organism has moved offshore, it determines that it should sample underwater sounds. This reduces noise in the collected sound data.

[0037] (Example 4) Furthermore, when targeting biological sounds, the distribution of organisms varies depending on environmental information such as water temperature, dissolved oxygen, salinity, and illuminance, so it is possible to conduct acoustic observations in advance only in the sea areas where the target organisms are distributed. The control unit 1 determines whether the organism wearing the measuring device 100 has moved to a water area with the desired marine environment, and when it determines that the organism has moved to a water area with the desired marine environment, it decides to perform underwater sound sampling. This allows sounds to be collected in the desired sea area.

[0038] (Example 5) Also, underwater sounds are acquired by low-frequency sampling, and the sound pressure and background noise level are determined. When the sound pressure is above a level previously stored in memory 5 or the background noise level is below a certain level, the control unit 1 decides to perform high-frequency sampling of the underwater sound. This allows noise to be reduced in the data to be collected. Also, when underwater sounds are sampled by low frequency sampling, the acoustic characteristics of a specific sound are determined, and if the acoustic characteristics match those previously stored in memory 5, the control unit 1 decides to perform high-frequency sampling of the underwater sound (for example, the sound is sampled at 10 kHz, and if the characteristics of the specific sound are observed, the sound is sampled at 200 kHz). This allows the specific sound to be collected efficiently. The above examples 1 to 5 make it possible to observe underwater sounds at appropriate timing (when significant data can be obtained), thereby reducing power consumption.

[0039] If the control unit 1 determines that sampling is to be performed by the high frequency sampling unit 4 (Yes in step S2), the control unit 1 proceeds to step S3. If the control unit 1 determines that sampling is not to be performed by the high frequency sampling unit 4 (No in step S2), the control unit 1 ends the processing in FIG. [Step S3] Upon receiving the instruction from the control unit 1, the high frequency sampling unit 4 measures underwater sounds using the underwater microphone 3 and stores the collected sound data thus obtained in the memory 5.

[0040] [Step S4] As described above, the data processing unit 6 reads out from the memory 5 the collected sound data sampled by the high frequency sampling unit 4 and performs edge processing on the read data.

[0041] [Step S5] The data transmission unit 7 transmits the data processed by the data processing unit 6 to, for example, a satellite or a base station. In this embodiment, data processing is performed each time sampling is performed and the data is transmitted. However, this is not limiting and the timing of data processing and data transmission may be performed at any timing.

[0042] As described above, the measuring device 100 of the embodiment has a low-frequency sampling unit 2 that detects the surrounding environment underwater by sampling approximately once per second, a control unit 1 that determines whether to detect underwater sounds based on the detection results of the low-frequency sampling unit 2, and a high-frequency sampling unit 4 that, when the control unit 1 determines that underwater sounds have been detected, detects underwater sounds at a frequency higher than the sampling frequency of the low-frequency sampling unit 2.

[0043] Underwater sounds (artificial sounds, environmental sounds, biological sounds) that are generally observed consist of sound waves in the frequency band from a few Hz to a few hundred kHz. For this reason, underwater sounds are often observed at a sampling frequency of tens of thousands to hundreds of thousands of times per second (i.e., several tens to a few hundred kHz). On the other hand, pressure sensors, temperature sensors, dissolved oxygen sensors, salinity sensors, and other sensors that measure the behavior and environment of marine organisms often observe at a sampling frequency of once per second at most. For this reason, if it were possible to determine whether to observe underwater sounds using behavior and environmental sensors, which have an extremely low sampling frequency, it would be possible to reduce power consumption.

[0044] In recent years, underwater sound observations have often required the understanding of so-called soundscape information, i.e., when and to what extent each sound source (artificial, environmental, or biological sound) is generating sound. However, acoustic information requires sampling at a higher frequency (up to several hundred kHz) than other sensors (such as temperature and pressure sensors), resulting in a large data volume and requiring significant power for recording. Transmitting massive amounts of data to a cloud server requires significant communication time and power, making edge processing, which processes data on the device itself, an effective approach. The measuring device 100 samples underwater sounds using the high-frequency sampling unit 4 to collect collected sound data in response to triggers from the behavior of living organisms or the environment, processes the collected sound data in the data processing unit 6, and transmits only the processed results to the cloud server, thereby reducing the time and power required for transmission. Collecting sound efficiently only for the required period also has the combined effect of reducing the amount of data required for edge processing.

[0045] It is also envisioned that the measuring device 100 will not be attached to a living organism. For example, the device can be installed on a stationary buoy, fish tank, or the like. Even in stationary observations on buoys or fish tanks, it is possible to conduct long-term observations using a limited battery by determining whether to conduct acoustic observations in response to triggers based on the environment or the state of the installed buoy or fish tank (such as its motion). Reducing power consumption not only improves the total operating period, but also enables the downsizing of the device, potentially simplifying the handling and installation of the device even in stationary observation devices. FIG. 5 illustrates an example of a hardware configuration of the measuring device according to the embodiment. The measuring device 100 is entirely controlled by a CPU (Central Processing Unit) 101 . A RAM (Random Access Memory) 102 and a plurality of peripheral devices are connected to the CPU 101 via a bus 106 .

[0046] The RAM 102 is used as a main storage device of the measuring device 100. The RAM 102 temporarily stores at least a part of the application program to be executed by the CPU 101. The RAM 102 also stores various data used in processing by the CPU 101. To the bus 106, an internal memory 103, various sensors 104, an underwater microphone 3, and a communication interface 105 are connected.

[0047] The built-in memory 103 writes and reads data. The built-in memory 103 is used as a secondary storage device for the measuring device 100. Application programs and various data are stored in the built-in memory 103. The built-in memory may be, for example, a semiconductor storage device such as a flash memory. The various sensors 104 are the sensors provided in the low frequency sampling unit 2 and the high frequency sampling unit 3 described above.

[0048] The communication interface 106 can be connected to a network 50. The communication interface 106 transmits and receives data to and from other computers or communication devices via the network 50. The battery 107 supplies control power to various devices. The processing functions of this embodiment can be realized by the hardware configuration described above.

[0049] While the measurement device of the present invention has been described above based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other components or steps may be added to the present invention. Furthermore, the present invention may be a combination of any two or more configurations (features) of the above-described embodiments.

[0050] The above processing functions can be realized by a computer. In this case, a program is provided that describes the processing contents of the functions possessed by the measuring device 100. The above processing functions are realized on the computer by executing the program on the computer. The program describing the processing contents can be recorded on a computer-readable recording medium. Examples of computer-readable recording media include magnetic storage devices, optical disks, magneto-optical recording media, and semiconductor memories. Examples of magnetic storage devices include hard disk drives, flexible disks (FDs), and magnetic tapes. Examples of optical disks include DVDs, DVD-RAMs, and CD-ROM / RWs. Examples of magneto-optical recording media include MOs (Magneto-Optical disks).

[0051] When distributing a program, for example, the program is recorded on a portable recording medium such as a DVD or CD-ROM and sold. Alternatively, the program can be stored in a storage device of a server computer and transferred from the server computer to other computers via a network.

[0052] A computer that executes a program stores, for example, a program recorded on a portable recording medium or a program transferred from a server computer in its own storage device. The computer then reads the program from its own storage device and executes processing in accordance with the program. Note that the computer can also read the program directly from a portable recording medium and execute processing in accordance with that program. The computer can also execute processing in accordance with the program received each time a program is transferred from a server computer connected via a network.

[0053] At least a part of the above processing functions can also be realized by electronic circuits such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or a PLD (Programmable Logic Device). [Explanation of symbols]

[0054] 1. Control section 2 Low-frequency sampling section 21 Environmental sensor section 211 Temperature Sensor 212 Salinity Sensor 213 Dissolved Oxygen Sensor 214 Illuminance sensor 22 Behavior Sensor Unit 221 Speed ​​sensor 222 Acceleration Sensor 223 Depth Sensor 224 Gyro Sensor 225 Geomagnetic Sensor 3 Underwater microphone 4 High frequency sampling section 5. Memory 6 Data Processing Unit 7 Data transmission section 100 Measuring Equipment

Claims

1. A measuring device to be attached to a living body, a first detection unit that detects the surrounding environment underwater at a first frequency; a determination unit that determines whether to detect underwater sound based on the detection result of the first detection unit; a second detection unit that detects underwater sounds at a frequency higher than the first frequency when the determination unit determines that underwater sounds have been detected; and the first detection unit detects the magnitude of movement of the living body; The measuring device is characterized in that the judgment unit judges that underwater sound has been detected when the magnitude of movement of the living body is equal to or less than a certain value.

2. A measuring device to be attached to a living body, a first detection unit that detects the surrounding environment underwater at a first frequency; a determination unit that determines whether to detect underwater sound based on the detection result of the first detection unit; a second detection unit that detects underwater sounds at a frequency higher than the first frequency when the determination unit determines that underwater sounds have been detected; and the first detection unit detects the position of the living body; A measuring device characterized in that the determination unit determines that underwater sound is detected when the position of the living body is in a position that is less susceptible to the influence of ambient sound.

3. a first detection unit that detects the surrounding environment underwater at a first frequency; a determination unit that determines whether to detect underwater sound based on the detection result of the first detection unit; a second detection unit that detects underwater sounds at a frequency higher than the first frequency when the determination unit determines that underwater sounds have been detected; and the first detector detects underwater sounds; The measuring device is characterized in that the judgment unit judges that an underwater sound has been detected when the volume of the detected sound is equal to or less than a certain level.

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