JP2014077703A - Fish species discrimination device, signal processing device, underwater detector, fish species discrimination method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately discriminate a fish species.SOLUTION: A fish species discrimination device 9 discriminating a fish species, using an ultrasonic echo signal transmitted towards underwater includes: a signal level acquisition part 14; a parameter calculation part 15; and a fish species specifying part 16. The signal level acquisition part 14 acquires a signal level of data generated from the echo signal. The parameter calculation part 15 calculates at least one of a change amount of the signal level and a degree of continuity of the signal level in a depth direction. The fish species specifying part 16 specifies the fish species on the basis of the change amount and the degree of continuity.

Description

  The present invention relates to a technique for transmitting an ultrasonic signal and discriminating a fish species based on the echo signal.

  2. Description of the Related Art Conventionally, an ultrasonic detection device that transmits an ultrasonic signal and detects a target from the echo signal is known. A fish finder is an example of the use of an ultrasonic detector. A fish finder generally detects an fish by transmitting an ultrasonic signal into the sea and receiving an echo signal reflected from a target such as a fish school. For example, an apparatus is known that transmits ultrasonic signals of two different frequencies and detects a school of fish having a specific body length by utilizing the difference in the reflectance of ultrasonic waves of two different frequencies (for example, , See Patent Document 1).

Japanese Patent Publication No. 40-25555

  Currently, annual fish catches are determined for each fish species, each country, and each fishing boat in order to protect global marine resources. For example, in TAC (Total Allowance Catch), the annual catch of each country is determined for each fish species. In IVQ (Individual Vessel Quota), the annual catch is determined for each fish type and each fishing boat. When landing over the set catch, various penalties will be imposed, such as reducing the catch of the next year.

  Therefore, it is anxious for each fishing boat to more reliably discriminate fish species before landing.

  Therefore, an object of the present invention is to accurately discriminate fish species.

  According to one aspect of the present invention, there is provided a fish type discriminating apparatus that discriminates a fish type using an ultrasonic echo signal transmitted toward the water, the signal level acquisition unit, the parameter calculation unit, and the fish type identification A part. The signal level acquisition unit acquires the signal level of data generated from the echo signal. The parameter calculation unit calculates at least one of the signal level change amount and the signal level continuity in the depth direction. The fish type specifying unit specifies the fish type based on the amount of change or the degree of continuity.

  According to the present invention, it is possible to accurately discriminate fish species.

Schematic configuration diagram of an underwater detector according to an embodiment Functional block diagram of the signal processing device of the underwater detector Example of image display when selecting a school of fish range in the signal processing device Graph showing parameters for fish species discrimination of the signal processing device Functional block diagram of a part of the fish type discriminating unit of the signal processing device A graph showing an example of signal level comparison for fish species discrimination by the fish species discriminator A graph showing an example of signal level comparison for fish species discrimination by the fish species discriminator A graph showing an example of signal level comparison for fish species discrimination by the fish species discriminator Flow chart showing the flow of processing by the fish species discriminating unit Functional block diagram of a part of the fish species discriminating unit of the signal processing device according to another embodiment

<1 First Embodiment>
Hereinafter, an underwater detector according to an embodiment of the present invention will be described with reference to the drawings.

  In the fish type discrimination according to the present embodiment, the fish type is discriminated by acquiring not only the signal level of the fish school (an example of the signal level) but also the degree of variation in the signal level of the fish school. The inventor of the present application discovers that there is a feature in the amount of change in the signal level and the degree of continuity of the signal level in the depth direction (hereinafter referred to as continuity), and discriminates the fish species using these parameters. This is what I thought of. Hereinafter, an embodiment thereof will be described.

<1-1 Underwater detector 1>
FIG. 1 schematically shows the configuration of an underwater detector 1 according to the embodiment. The underwater detector 1 includes a transducer 2, a transmission / reception unit 3 (an example of a transmission / reception device), a signal processing device 10, a display unit 4 (an example of a display device), and an operation unit 5.

  The transmitter / receiver 2 is mounted on the bottom of a ship and is configured by bundling a required number of ultrasonic transducers, which are electromechanical conversion elements, with their transmission surfaces facing one side. The transmitter / receiver 2 transmits ultrasonic waves toward the water based on ultrasonic signals of each frequency generated by the transmitter 33 described later. The transmitter / receiver 2 receives reflected waves generated by the reflected ultrasonic waves of each frequency reflected on a target such as a school of fish with an ultrasonic transducer, generates an echo signal for each frequency, and will be described later. Output to the receiver 32.

  The transmission / reception unit 3 transmits and receives signals between the transducer 2 and the signal processing device 10, and includes a transmission / reception switching unit 31, a reception unit 32, and a transmission unit 33.

  The transmission / reception switching unit 31 is a circuit or the like for switching the signal path, and guides the ultrasonic signal from the transmission unit 33 to the transducer 2 while guiding the echo signal from the transducer 2 to the reception unit 32.

  The receiving unit 32 samples the echo signal of each frequency for each PING input from the transmission / reception switching unit 31 at a predetermined sampling timing interval, and generates reception data for each frequency. This sampling timing interval is set based on the distance resolution in the depth direction, for example. The receiving unit 32 outputs received data for each PING to the signal processing device 10.

  The transmission unit 33 generates an ultrasonic signal having a predetermined frequency and outputs it to the transducer 2. The transmission unit 33 is configured to generate an ultrasonic signal having a plurality of frequencies, and generates at least two types of ultrasonic signals having different frequencies. For example, an ultrasonic signal of 60 kHz is generated as the first frequency, and an ultrasonic signal of 200 kHz is generated as the second frequency. The combination of frequencies is not limited to this, and can be set as appropriate depending on the target fish species. The transmitter 33 outputs the first frequency and the second frequency to the transducer 2 at a predetermined timing interval.

  The signal processing device 10 converts the received signal into a digital signal and performs predetermined signal processing. The signal processing device 10 is, for example, a device including a processor or a memory, an integrated circuit, or the like, and processes reception data output from an A / D conversion unit described later to generate an image signal. The signal processing device 10 is realized by, for example, a general-purpose DSP or FPGA that executes a program stored in a memory. The signal processing device 10 can also be realized by a digital circuit such as an ASIC (Application Specific Integrated Circuit).

  The display unit 4 has a screen such as an LCD (Liquid Crystal Display). For example, the display device 4 displays an echo image corresponding to the received data with the vertical axis of the screen as the depth direction and the horizontal axis as the time direction (transmission direction or KP direction). The display unit 4 also displays information on the fish species determined by the signal processing device 10 as will be described later. Note that the echo image display of the normal received data and the display of the information regarding the identified fish species may be displayed by the user operating the operation unit 5 or automatically switched.

  The operation unit 5 is a mouse, a touch panel, a keyboard, or the like, and the user inputs information by a predetermined input operation.

<1-2 Signal Processing Device 10>
<1-2-1 Configuration of Signal Processing Device 10>
FIG. 2 shows a functional configuration of the signal processing apparatus 10. The signal processing device 10 includes an A / D conversion unit 11, a reception data storage unit 12, a fish school range selection reception unit 13, a signal level acquisition unit 14 (an example of a signal level acquisition unit), a parameter calculation unit 15, It has a fish type identification unit 16 and a display control unit 17. The signal level acquisition unit 14, the parameter calculation unit 15, and the fish type identification unit 16 constitute a fish type determination unit 9 (an example of a fish type determination device).

  The A / D conversion unit 11 converts the received data input from the transmission / reception unit 3 into a digital signal.

The reception data storage unit 12 sequentially stores the reception data digitized by the A / D conversion unit 11.

  The fish school range selection accepting unit 13 accepts selection of a predetermined range by the user for the received data. For example, as shown in FIG. 3, the user views a echo image corresponding to the received data displayed on the display unit 4 and operates the operation unit 5 to select a predetermined fish school range 41. Here, the user confirms the level of the echo signal in the depth direction, specifies a portion where the signal level is high in the predetermined range in the depth region where the fish school is assumed to exist, and sets the predetermined fish school range 41 .

  The signal level acquisition unit 14 acquires signal levels of reception data of two frequencies (high frequency and low frequency) for the predetermined fish range 41 selected by the fish range selection reception unit 13.

  The parameter calculation unit 15 acquires, from the signal level of the received data acquired by the signal level acquisition unit 14, histogram values for the three parameters of signal level (dB), change amount, and continuity in the depth direction. To do.

  Here, the amount of change is a difference in signal level between adjacent sample points, as shown in FIG. Here, the dots representing the depth shown in the figure correspond to the sampling points of the received data. It is assumed that the sampling interval of received data is matched with a sampling interval related to reference data described later. In addition, a predetermined depth length representing the amount of change is also matched with the reference data.

  The continuity is an interval (number of dots) from the rising edge to the falling edge when a signal level of a certain level or more continues in the depth direction as shown in FIG. Indicates the length (width in the depth direction, number of dots) that the level continues.

  As illustrated in FIG. 5, the parameter calculation unit 15 includes a signal level calculation unit 151, a change amount calculation unit 152, and a continuity calculation unit 153. The signal level calculation unit 151 forms a histogram of the signal level of the received data (see FIG. 6). The change amount calculation unit 152 forms a histogram of the change amount of the signal level (see FIG. 7). The continuity calculation unit 153 forms a histogram of the continuity of the signal level in the depth direction (see FIG. 8).

  As shown in FIG. 5, the fish type identification unit 16 includes a signal level comparison unit 161, a change amount comparison unit 162, a continuity comparison unit 163, and a fish type determination unit 164, and is calculated by the parameter calculation unit 15. The fish type is identified using the values of the three parameters of the signal level, the amount of change, and the continuity. 6 to 8 show comparative examples of parameters.

  The signal level comparison unit 161 compares the histogram acquired by the parameter calculation unit 15 and the reference data for the signal level of the reception data of each frequency (for example, 200 kHz and 60 kHz). The reference data is a signal level histogram pattern measured in advance for each fish species and stored in a memory or the like. 6 (a) and 6 (b) are histograms with the signal level of −70 dB to −20 dB as the horizontal axis and the appearance frequency as the vertical axis. The received data and each fish species (here, herring) An example of the reference data of Aji and Aji. The received data is indicated by a black line, the herring reference data is indicated by a gray line, and the reference data for horse mackerel is indicated by a dotted line. The signal level comparison unit 161 compares the histogram of the signal level of the received data with each reference data (for example, compares peak positions), calculates the similarity (correlation) or difference, and outputs the result. As for horse mackerel and herring, the peak of the signal level histogram of horse mackerel tends to be higher than herring. In addition, horse mackerel has a so-called tailing (a signal region adjacent to the signal region of the fish school, which becomes longer when the reflected wave of the fish school is strong) under the fish school, and therefore tends to have a peak even at a low signal level.

  The change amount comparison unit 162 compares the change amount histogram acquired by the parameter calculation unit 15 with the reference data for the signal level of the reception data of each frequency (for example, 200 kHz and 60 kHz). The reference data is a histogram pattern of the amount of change measured in advance for each fish species and stored in a memory or the like. 7 (a) and 7 (b) are histograms in which the horizontal axis represents the amount of change in the signal level of −20 dB to 20 dB and the vertical axis represents the frequency of appearance thereof. An example of reference data of herring and horse mackerel) is shown. The received data is indicated by a black line, the herring reference data is indicated by a gray line, and the reference data for horse mackerel is indicated by a dotted line. The change amount comparison unit 162 compares the histogram of the change amount of the signal level of the received data with the reference data (for example, compares the peak positions), calculates the similarity (correlation degree) or the difference, and outputs it. As a trend, since the amount of change in signal level is smaller in horse mackerel, the frequency of appearance of signal levels near 0 dB in the histogram is higher. From this, the peak of the histogram regarding the amount of change in horse mackerel is higher than that of herring.

  The continuity comparison unit 163 compares the signal level of the reception data of each frequency (for example, 200 kHz and 60 kHz) with the histogram of the continuity in the depth direction acquired by the parameter calculation unit 15 and the reference data. The reference data is a histogram pattern of continuity measured in advance for each fish species and stored in a memory or the like. 8 (a) and 8 (b), the horizontal axis indicates the interval (number of dots) from the rising edge to the falling edge when signal levels of a certain level or more continue in the depth direction, and the frequency of occurrence is expressed vertically. It is a histogram with an axis, and shows an example of received data and reference data for each fish species (here, herring and horse mackerel). The continuity comparison unit 163 compares the histogram of the continuity in the received data with reference data (for example, compares peak positions), calculates the similarity or difference (correlation), and outputs the result. As a tendency, horse mackerel has more than a plurality of dots (that is, the continuity is low). Therefore, the peak in the histogram is lower for horse mackerel.

  The fish type determination unit 164 scores the degree of similarity, etc., which is a comparison result between the received data value and the reference data for each parameter acquired by the signal level comparison unit 161, the change amount comparison unit 162, and the continuity comparison unit 163. To determine the fish species close to the reference data. When it is judged that there is no similarity and it does not correspond to any fish species, it is judged as impossible.

  The display control unit 17 causes the display unit 4 to display information related to the fish type specified by the fish type specifying unit 16 (information for specifying the fish type) and a result that cannot be determined, or to visualize the fish school area. And so on.

  In addition, although illustration is abbreviate | omitted here, the display control part 17 performs the process which visualizes the reception data acquired from the reception data memory | storage part 12 as a function of a normal underwater detector. That is, the display control unit 17 performs a process for displaying each reception data sequentially recorded on the display unit 4 as an echo image corresponding to the depth according to the elapsed time after outputting the ultrasonic wave.

<1-2-2 Operation of Fish Type Discriminating Unit 9>
FIG. 9 is a flowchart of processing performed by the fish type determination unit 9 according to the present embodiment.

  Step S101: It is determined that a predetermined fish school range of the received data has been selected by the fish school range selection accepting unit 13 through a user operation.

  Step S102: The signal level of the reception data of the two frequencies in the fish school range selected in step S101 is acquired.

  Step S103: From the signal level of the reception data of the two frequencies acquired in step S102, values obtained as histograms are acquired for the three parameters of the signal level, the amount of change, and the continuity in the depth direction.

  Step S104: The histogram value of each parameter acquired in step S103 is compared with the reference data, the similarity and difference are calculated, and output as a comparison result.

  Step S105: The comparison result calculated in step S104 is scored, and the fish type is determined based on the total value. When it is judged that there is no similarity and it does not correspond to any fish species, it is judged as impossible.

  Step S106: Information on the fish type specified in step S105, the result of the determination impossible, and the like are displayed on the display unit 4.

  In addition, the execution order of the processing method in the said embodiment is not necessarily restrict | limited to description of the said embodiment, The execution order can be changed in the range which does not deviate from the summary of invention.

<1-3 Features of this Embodiment>
According to the fish type discriminating unit 9 according to the above embodiment, the fish type is discriminated using not only the signal level of the echo signal of the school of fish but also other parameters such as correlation and continuity of the signal level in combination. This makes it possible to distinguish the fish species with high accuracy.

<2 Other Embodiments>
<2-1>
In the fish kind discrimination | determination part 9 which concerns on the said embodiment, although a fish kind is discriminate | determined using three parameters, a signal level, a variation | change_quantity, and the continuity of a depth direction, it is not limited to this. For example, even if the determination is performed using two parameters of the signal level and the change amount, the signal level and the continuity, or the change amount and the continuity, a certain accuracy can be obtained.

  Alternatively, even if the fish type discrimination is performed using only one of the signal level change amount and the continuity parameter, a certain accuracy can be obtained.

  The comparison between the histogram of each parameter and the reference data is not limited to the comparison of peak positions. For example, the shape of the histogram, that is, the similarity of distribution may be calculated.

<2-2>
In the said embodiment, although the signal processing apparatus 10 performs even the discrimination of a fish species, this invention is not limited to this. For example, the signal processing apparatus 10 does not perform fish species discrimination, but compares the three parameter values of the signal level, change amount, and continuity calculated by the parameter calculation unit 15 with the reference data, and the similarity (correlation). Degree) or a difference may be calculated, and the calculation result may be displayed as information for specifying the fish species. In this case, the fish type is specified by the user based on the displayed similarity.

  In this case, the signal processing apparatus 10 includes a similarity determination unit 18 instead of the fish species identification unit 16 as shown in FIG. The similarity determination unit 18 is the same as the first embodiment in that it includes a signal level comparison unit 161, a change amount comparison unit 162, and a continuity comparison unit 163, but does not have a fish type determination unit 164. It is different. The similarity or difference (correlation) obtained as a comparison result between the received data value and the reference data for each parameter acquired by the signal level comparison unit 161, the change amount comparison unit 162, and the continuity comparison unit 163 is displayed. It is transmitted to the control unit 17 (FIG. 2) and displayed by the display unit 4 (FIG. 2).

  Other configurations and functions are the same as those in the first embodiment.

<2-3>
In the fish type discriminating unit 9 according to the above embodiment, the fish type specifying unit 16 discriminates between herring and horse mackerel, but the present invention is not limited to this. Another type of fish may be discriminated using reference data obtained and stored in advance with respect to other types of fish and the above parameters.

<2-4>
In the fish type discriminating unit 9 according to the above embodiment, the fish type is discriminated using the signal level of the received data, but the fish type is discriminated based on other signal information (for example, volume scattering intensity). Also good.

<2-5>
According to the fish type discriminating unit 9 in the underwater detector 1 according to the above embodiment, the processing is performed on the reception data of two frequencies, but the processing may be performed using the reception data of only one frequency. In addition, in the case of an underwater detector that can receive the reception data of 3 frequencies or more, the same processing may be performed on the reception data of 3 frequencies or more. You may make it process by selecting. In this case, which frequency is selected may be dynamically set according to the environment.

  Note that even when reception data of only one frequency is used (for example, when only histogram data based on reception data of one frequency in FIGS. 6 to 8 is used), the operational effects of the present invention can be obtained. Further, when using reception data of two or more frequencies as in the above embodiment, the fish type determination is performed based on more data, so the accuracy of fish type determination can be improved.

<2-6>
In the above embodiment, the fish type discrimination unit 9 has been described as an apparatus or an integrated circuit, but the present invention can also be realized as a fish type discrimination method or a computer program.

DESCRIPTION OF SYMBOLS 1 Underwater detector 2 Transceiver 3 Transmission / reception part 4 Display part 5 Operation part 9 Fish type discrimination | determination part 10 Signal processing apparatus 11 A / D conversion part 12 Received data storage part 13 Fish school range selection reception part 14 Signal level acquisition part 15 Parameter Calculation unit 16 Fish species identification unit 17 Display control unit 18 Similarity determination unit 151 Signal level calculation unit 152 Change amount calculation unit 153 Continuity calculation unit 161 Signal level comparison unit 162 Change amount comparison unit 163 Continuity comparison unit 164 Fish type determination Part

Claims (13)

A fish type discrimination device that discriminates a fish type using an ultrasonic echo signal transmitted toward the water,
A signal level acquisition unit for acquiring a signal level of data generated from the echo signal;
A parameter calculation unit that calculates at least one of the amount of change in the signal level and the continuity of the signal level in the depth direction, and a fish type identification unit that specifies a fish type based on the amount of change or the continuity,
A fish species discrimination device. The amount of change in the signal level is a difference in signal level between adjacent sample points in the data.
The fish type discrimination device according to claim 1. The continuity of the signal level is a length in the depth direction in which the signal level continues for a predetermined threshold or more.
The fish type discrimination device according to claim 1. The fish species identification unit identifies a fish species based on the signal level and the amount of change or the continuity.
The fish type discrimination device according to claim 1. The fish species identification unit identifies a fish species based on the signal level, the amount of change, and the continuity.
The fish type discrimination device according to claim 4. The fish species specifying unit compares the reference data acquired for each fish species with the signal level, and selects the fish species based on the change amount or the continuity similarity between the reference data and the signal level. Identify,
The fish type discrimination device according to claim 1. The fish species identification unit compares the reference data acquired for each fish species with the signal level, and identifies the fish species based on the similarity of the signal level between the reference data and the signal level,
The fish type discrimination device according to claim 4. The data is generated based on ultrasonic echo signals transmitted at a plurality of frequencies, respectively.
The fish type discrimination device according to claim 1. A fish type discrimination device that discriminates a fish type using an ultrasonic echo signal transmitted toward the water,
A signal level acquisition unit for acquiring a signal level of data generated from the echo signal;
A parameter calculation unit that calculates at least one of the amount of change in the signal level and the continuity of the signal level in the depth direction, and compares the reference data acquired for each fish species with the signal level, and the reference data and the A similarity determination unit that calculates the degree of change between the signal levels or the degree of continuity;
A fish species discrimination device. The fish type identification device according to claim 1 or 9,
An A / D converter that digitally converts the echo signal to generate the data; and a memory that stores the data;
A signal processing apparatus comprising: The signal processing device according to claim 10,
A transmitter / receiver for transmitting the ultrasonic transmission signal toward the water and receiving the echo signal;
A transmission / reception device that generates the ultrasonic transmission signal and outputs the ultrasonic signal to the transmitter / receiver, receives the echo signal from the transmitter / receiver, and outputs the signal to the signal processing device, and the fish type determination of the signal processing device A display device for displaying information for identifying the fish species output by the device;
Underwater detector equipped with. A fish type discrimination method for discriminating a fish type using an ultrasonic echo signal transmitted toward the water,
Obtain the signal level of the data generated from the echo signal,
Calculating at least one of the amount of change in the signal level in the depth direction and the continuity of the signal level;
Identify fish species based on the amount of change or the continuity,
Fish species discrimination method.   A computer program for causing a computer to execute the fish species discrimination method according to claim 12.

Images