JP2002181618A - Fishing ground watcher - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fishing ground watcher for detecting a doubtful ship (a poaching boat) for preventing poaching and reducing damage by the poaching. SOLUTION: The approach of the doubtful ship can be detected by detecting a ship sound by watching a sea area on the basis of an acoustic signal captured by a microphone arranged in the sea. A characteristic composed of a frequency combination of ship sounds is extracted, and is recorded on a database so that a history can be referred to. The acoustic sound is detected by plural microphones, and a relative position is seized so that the advancing direction of the doudtful ship can be estimated. Thus, a quick countermeasure can be taken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sea area monitoring device for monitoring a poaching boat or the like illegally entering a fishing ground, and more particularly to a fishing ground monitoring device.

[0002]

2. Description of the Related Art Conventionally, in a sea area monitoring device for monitoring poaching boats to prevent poaching, video cameras or infrared cameras and radars installed on land are used to monitor approach and intrusion of poaching boats to fishing grounds. I was However, at midnight when poaching occurs frequently, the size of the fishing ground that can be monitored by the camera is limited by the lighting and the imaging capability of the camera. In addition, it was necessary to construct a complex feature extraction algorithm to digitally process the captured image and automatically identify poaching vessels. In addition, since poaching boats are relatively small and approach the fishing grounds close to large vessels passing near the fishing grounds, radar for wide-area monitoring cannot distinguish between the two vessels due to lack of resolution. In some cases, the intrusion of poaching boats was missed.

[0003] A fishing ground needs to be monitored by a monitoring information source with a small blind spot, both day and night, even on complicated terrain. In the case of the sea area monitoring device using the conventional camera,
Monitoring by a camera can be performed at a relatively long distance in the daytime, but at midnight when poaching occurs frequently, the monitoring range is limited due to insufficient light quantity. In addition, the camera's view range is limited to a straight line within the angle of view, so that in the case of complicated terrain, the monitoring range is significantly limited. Also, it is difficult to determine when a poaching boat enters a large passing boat by radar monitoring.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to detect an intrusion of a poaching boat at an early stage and to take quick action. As a similar technique, there is a method of identifying the presence or absence of a sound wave key. Although this method detects all boats other than legitimate work boats as suspicious boats, the present invention extracts the characteristics of poaching boats, identifies the boats, and compares the poaching boats with the past history. Can be checked.

[0005]

As a means for stably monitoring a fishing ground throughout the day and night, acoustic information captured by a microphone installed in the sea is used. Since underwater acoustic information propagates over a wide area, it is possible to detect the approach of poaching boats even at long distances or in complicated terrain. In addition, a frequency component is analyzed by performing a Fourier transform on the acoustic signal captured by the microphone, and discrimination between ship sound and noise and feature extraction from a combination of frequency components of the ship sound are performed. By recording the ship sound pattern composed of this frequency combination in the database, it is possible to compare and contrast with the past history. In addition, the wake of a poaching boat is estimated by using the acoustic information obtained from a plurality of microphones and comparing the installation position information of the microphone to which a high-level acoustic signal is input.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a fishing ground monitoring device of the present invention. 2 is a receiver installed under the sea and converts an acoustic signal into an electric signal. 3 is a frequency analyzer which analyzes a frequency component of the acoustic signal. 4 is a high-frequency component extracted from the frequency component information. A discriminating unit for discriminating the ship sound and the ship sound pattern, a database unit for recording the ship sound pattern, an alarm generating unit for generating an alarm based on information from the discriminating unit, and an alarm valid time 7 A timer section 8 for setting is an alarm control section for controlling an alarm generating section in conjunction with the timer.

The poaching boat 9 emits a ship sound 10 generated from inside and outside the sea in response to the operation of an engine, a screw, and other electric and mechanical mechanisms. In the sea, there is a noise 11 composed of a breaking sound of a wave, a sound emitted from a marine creature or the like.

[0008] The receiving section 2 receives acoustic signals from the sea including the ship sound 10 and the noise 11 in time series and sends them to the frequency analyzing section 3. The frequency analysis unit 3 performs a Fourier transform on the received acoustic signal, and extracts a frequency component according to Equation 1.

[0009]

(Equation 1)

[0010] Here, f (t) is an acoustic signal expressed as a function of time (t). The acoustic signal replaced with the frequency component is discriminated into a ship sound and a noise by the discriminating unit 4, and the discriminating unit extracts the characteristics of the ship sound. Since the ship sound is mainly caused by the engine speed and the screw sound, it has a relatively low frequency band of 1 Hz to several thousand Hz, so that high frequency components can be regarded as noise. Further, by extracting and comparing the characteristics of the underwater sound when there is no ship sound, the ship sound and the noise can be distinguished.

[0011] Further, the frequency combination unique to the ship, for example, one ship has a high level at frequencies of X ₁ Hz, X ₂ Hz, X ₃ Hz, ..., and another ship has Y ₁ Hz, Y ₂ Hz, Specific patterns such as having a high level at a frequency of Y ₃ Hz,... Can be extracted. If there are two vessels, a large passing boat and a small poaching boat, a small poaching boat can be detected, for example, by performing a filtering process that removes the frequency components that are characteristic of large vessels that are registered in advance. It is. By recording the combination of the frequency patterns in the database unit 5, it is possible to leave the history of the vessels approaching the monitoring area.

Next, the signal of the ship sound separated by the discriminating section 4 is sent to the alarm generating section 6, and an alarm indicating the approach of the ship is generated. Here, in the daytime, when there is no need to generate an alarm, for example, when a fishing ground-related person is in the monitoring target area, an alarm generating target time zone is set in the timer unit 7, and the alarm control unit 8 operates in conjunction with the alarm control. By controlling the occurrence, the occurrence of unnecessary alarms is suppressed.

FIG. 2 shows an embodiment in which a plurality of microphones are installed in the receiving section 2. In FIG. 2, reference numeral 2 denotes a plurality of receiving units which are installed under the sea and convert sound signals into electric signals
Reference numerals a, 2b and 2c denote microphones constituting a receiving unit, 3 denotes a frequency analyzing unit, and 4 denotes a discriminating unit. It is assumed that the poaching boat 9 emitting the boat sound 10 at a certain time t1 moves with time, and after a time t2, emits a boat sound 10a at a location of the poaching boat 9a at a time t3. At this time, a graph 12 shows the relationship between the acoustic signal obtained by the determination unit 4 and the time. In the microphone 2a, the level of the input acoustic signal changes at time t1.
Indicates a maximum, and thereafter gradually attenuates, whereas the level of the acoustic signal indicates the maximum at time t2 for the microphone 2b and at time t3 for the microphone 2c. Microphones 2a, 2
By knowing the installation positions of b and 2c in advance, it is possible to estimate the direction in which the poaching boat 9 moves with respect to the microphones 2a, 2b and 2c. By estimating the traveling direction of the poaching boat 9 in this manner, it is possible to perform a coping action ahead of time.

[0014]

The present invention can contribute to early detection of poaching boats. Also, by extracting the characteristics of the ship sound and comparing it with the past history, it can be determined whether or not the approaching suspicious boat is a poaching boat with a previous history. In addition, it is possible to estimate a wake by using a plurality of microphones, and to take quick action to cope with a poaching boat.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a fishing ground monitoring device of the present invention.

FIG. 2 is a diagram showing an application example of the fishing ground monitoring device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fishing ground monitoring apparatus 2 ... Reception part 3 ... Frequency analysis part 4 ... Judgment part 5 ... Database part 6 ... Alarm generation part 7 ... Timer part 8 ... Alarm Control unit 9 Poaching boat 10 Boat sound 11 Underwater noise 2a Microphone 1 2b Microphone 2 2c Microphone 3 9a Poaching boat (after moving) 10a ..Sound of ship 12... Diagram showing transition of acoustic signals of a plurality of microphones obtained by discriminator 4.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G047 BC04 EA04 EA10 EA11 GD02 GG12 GG17 2G064 AA14 AB13 AB20 AB21 AB29 BD02 CC41 CC61 5J083 AA05 AD01 AE02 BE41 BE53

Claims (4)

[Claims] 1. A fishing ground monitoring apparatus including a microphone for acquiring sound in the sea, a receiving section for converting an underwater acoustic signal into an electric signal, a frequency analyzing section for analyzing the received acoustic signal, and a receiving section for performing frequency analysis. A fishing ground monitoring apparatus comprising: a discriminating unit that discriminates a detected underwater sound from a ship sound and a noise. 2. A fishing ground monitoring apparatus according to claim 1, wherein a plurality of microphones are simultaneously connected to acquire an acoustic signal.
A fishing ground monitoring device that performs a wide range monitoring and estimates a position of a boat in a fishing ground from a level transition of an acoustic signal input to each microphone. 3. The fishing ground monitoring apparatus according to claim 1, wherein said database unit records frequency component combination information, and said frequency combination of ship sounds extracted by said frequency analysis unit and said discrimination unit is data recorded in said database unit. A fishing ground monitoring device characterized in that it compares the history with the sound of past ships in comparison with the above. 4. A fishing ground monitoring apparatus according to claim 1, wherein an alarm generating section for generating an alarm signal based on a signal from the discriminating section, a timer section for generating a time signal, and interlocking with the timer section within a regular working time. A fishing ground monitoring device comprising an alarm control unit for suppressing and controlling occurrence of an alarm.