Method or system for continuous remote sensing of sea surface temperature

Abstract

To provide a continuous telemetry method of sea surface temperature capable of measuring sea surface temperature continuously and properly from a remote place using a thermal camera installed on land.SOLUTION: The continuous telemetry method of sea surface temperature using a swiveling thermal camera 11 includes; a measurement step of measuring sea surface temperature at least 3 points with a thermal camera 11; a correction value calculation step of calculating a correction value for correcting the sea surface temperature measured in the measurement step; a correction step of correcting the measured sea surface temperature based on the correction value calculated in the correction value calculation step and storing the corrected sea surface temperature in a storage device; and a continuous measurement step of executing continuously the measurement step and the correction step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method or system for continuous remote measurement of sea surface temperature, which continuously measures sea surface temperature remotely. [Background technology]

[0002] In the past, there have been reports of damage caused by kyucho (a sudden tidal current) washing away or damaging fixed nets deployed in coastal waters, and in order to prevent such damage, progress is being made in the development of technology to detect signs of the kyucho phenomenon. For example, Non-Patent Document 1 proposes a method of detecting a kyucho by detecting a sudden rise in seawater temperature, since a kyucho is often accompanied by a sudden rise in seawater temperature. Furthermore, as a method for measuring seawater temperature, a device is known in which a group of sensors, such as temperature sensors, are led from a closure (measurement buoy) installed on the ocean and brought into contact with seawater to directly measure marine environmental information such as seawater temperature (for example, Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Sakae Inaba and Takaaki Katsumata, "Quick Currents in Suruga Bay Detected by a Sudden Rise in Water Temperature," Ocean: Nature and Culture, Tokai University Journal of Marine Science and Technology, Vol. 1, No. 1, 2003 [Patent documents]

[0004] [Patent Document 1] JP 2017-075956 A Summary of the Invention [Problem to be solved by the invention]

[0005] When measuring seawater temperature using a measurement buoy as in Patent Document 1, there are problems in that the measurement buoy is expensive, it is difficult to measure seawater temperature over a wide area on the ocean, and maintenance is difficult because it is on the ocean. Furthermore, there is a problem in that the installation locations for the measurement buoy are limited. Therefore, the inventors have studied a method of detecting seawater temperature using a thermal camera that is installed on land and captures a thermographic image of the sea surface from a remote location. However, in order to measure the seawater temperature over a wide area on the ocean using a thermal camera installed on land, the thermal camera needs to be installed at a location away from the ocean. In this case, however, some of the infrared rays emitted from the ocean cannot be received, and the seawater temperature measured by the thermal camera is lower than the actual seawater temperature. In addition, because the ocean surface is constantly pulsating with waves, the amount of infrared light received by a thermal camera changes depending on the wave conditions, which creates the problem of variation in the sea surface temperature measured by the thermal camera.

[0006] The present invention aims to provide a method for remotely and continuously measuring sea surface temperature using a thermal camera installed on land. [Means for solving the problem]

[0007] The method for continuous remote measurement of sea surface temperature of the present invention is a method for continuous remote measurement of sea surface temperature using a rotatable thermal camera, comprising: a measurement step of measuring the sea surface temperature at three or more points with the thermal camera; a correction value calculation step of calculating a correction value for correcting the sea surface temperature measured in the measurement step; a correction step of correcting the measured sea surface temperature based on the correction value calculated in the correction value calculation step and storing the corrected sea surface temperature in a storage device; and a continuous measurement step of continuously executing the measurement step and the correction step. In the correction value calculation step, a predetermined reference correction value is adjusted based on the magnitude of the sea surface temperature measured by the thermal camera at each measurement point, thereby calculating the correction value for each measurement point. . In the above-mentioned method for continuous remote measurement of sea surface temperature, in the correction value calculation process, the predetermined standard correction value is further adjusted based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point, thereby calculating the correction value for each measurement point. In the above-mentioned method for continuous remote measurement of sea surface temperature, the correction step may be configured to correct the measured sea surface temperature after masking the portion above the horizon in the image captured by the thermal camera. In the above-mentioned method for continuous remote measurement of sea surface temperature, the continuous measurement step may be performed while rotating the thermal camera horizontally. In the above-mentioned method for continuous remote sensing of sea surface temperature, in the correction value calculation step, The above The correction value can be measured by adding a first adjustment value based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point, and a second adjustment value based on the sea surface temperature measured by the thermal camera to a predetermined reference correction value. The above-mentioned method for continuous remote measurement of sea surface temperature can be configured to include an average temperature calculation step of calculating a daily average of the measured sea surface temperature, and an alert step of issuing an alert indicating a sign of a kyucho phenomenon if the average value of the sea surface temperature calculated at the same measurement point has risen by a certain amount or more from the average value of the sea surface temperature of the previous day. In the above-mentioned method for continuous remote measurement of sea surface temperature, the thermal camera can be configured to be installed at a location 30 m to 500 m above sea level. In the above-mentioned method for continuous remote measurement of sea surface temperature, the thermal camera can be configured to measure the sea surface temperature at a measurement point at a distance of 100 m to 3000 m from the thermal camera. In the above-mentioned method for continuous remote measurement of sea surface temperature, the thermal camera may be configured so that the depression angle is set to 1.8° or more. The continuous remote measurement system according to the present invention includes a rotatable thermal camera that measures sea surface temperature at three or more points, and a control unit that calculates a correction value for correcting the sea surface temperature measured by the thermal camera and corrects the sea surface temperature measured by the thermal camera based on the correction value, and the sea surface temperature continuously measured by the thermal camera is corrected by the control unit with the correction value, thereby continuously measuring the sea surface temperature. The control unit calculates the correction value for each measurement point by adjusting a predetermined reference correction value set in advance based on the magnitude of the sea surface temperature measured by the thermal camera at each measurement point. . In the above continuous remote measurement system, the control unit can be configured to calculate a correction value for each measurement point by further adjusting the predetermined reference correction value based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point. In the above-mentioned continuous remote measurement system, the control unit can be configured to calculate the daily average of the sea surface temperature measured by the thermal camera, and if the average value of the sea surface temperature calculated at the same measurement point has risen by a certain amount or more from the average value of the sea surface temperature of the previous day, to issue an alert indicating an indication of a kyucho phenomenon. Effect of the Invention

[0008] According to the present invention, the sea surface temperature measured by a thermal camera can be appropriately corrected, so that the sea water temperature can be appropriately measured continuously and remotely using a thermal camera installed on land. [Brief description of the drawings]

[0009] [Figure 1] 1 is a configuration diagram showing a quick tide detection system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a measurement range of sea surface temperature of the thermal camera according to the embodiment. [Diagram 3] 1 is a graph showing an example of the difference between the camera measurement value of the sea surface temperature measured by a thermal camera and the actual measurement value of the sea surface temperature measured by a contact thermometer. [Figure 4] 11 is a graph showing the relationship between the distance from a thermal camera to a measurement point and a first adjustment value. [Diagram 5] 13 is a graph showing the relationship between the provisional value of sea surface temperature (the moving average value of camera measurement values) and the second adjusted value. [Figure 6] 1 is a diagram for explaining an example of a method for detecting a symptom of a quick tide phenomenon according to the present embodiment. FIG. [Figure 7] This is a graph showing the actual measured value, the provisional sea surface temperature (the moving average value of the camera measurement value), the temperature difference between the actual measured value and the provisional sea surface temperature, and the corrected sea surface temperature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a configuration diagram showing a quick tide detection system 1 according to this embodiment. As shown in Fig. 1, the quick tide detection system 1 according to this embodiment is composed of a camera device 10 and a control device 20.

[0011] As shown in FIG. 1, the camera device 10 includes a thermal camera 11, a floodlight 12, a camera controller 13, and a communication device 14. The thermal camera 11 includes a thermal camera section for capturing thermographs and a color camera section for capturing color images. The image data (thermography and color image data) captured by the thermal camera 11 is output to the camera controller 13, and then transmitted to the control device 20 by the communication device 14 via the Internet line 30. In this embodiment, the thermal camera 11 captures thermographs and color images every second, and transmits the captured thermographs and color image data to the control device 20. In this way, the camera device 10 according to this embodiment can capture thermographs and color images every second, making it possible to measure the sea surface temperature in real time. The floodlight 12 is a light for illuminating the location to be captured at night, etc., and operates under the control of the camera controller 13.

[0012] Here, Fig. 2(A) and (B) are diagrams showing an example of the imaging range of the thermal camera 11 according to this embodiment. Since the thermal camera 11 captures thermography within the angle of view of the lens, as shown in Fig. 2(A) and (B), it is possible to measure the sea surface temperature at a plurality of measurement points captured as thermography at once. For example, in the example shown in Fig. 2(A) and (B), the thermal camera 11 can simultaneously measure the sea surface temperature at five measurement points (a) to (e) from one thermography. In addition, the thermal camera 11 according to this embodiment is capable of rotating (panning) the camera in the left-right direction (horizontal direction), and can capture the sea surface in a range wider than the angle of view of the camera in the left-right direction. Similarly, the thermal camera 11 is also capable of rotating (tilting) the camera in the up-down direction, and can capture the sea surface in a range wider than the angle of view of the camera in the up-down direction. In this way, the thermal camera 11 can measure the sea surface temperature at multiple measurement points on the ocean by rotating the camera left and right, up and down (it can measure the sea surface temperature over a wider range than the range shown in Figs. 2(A) and (B)). Also, in thermography, the measurement accuracy is higher toward the center of the image, so the thermal camera 11 can be configured to rotate the camera left and right, up and down so that the measurement point is at the center of the image.

[0013] In order to suitably measure the sea surface temperature, the larger the depression angle of the thermal camera 11 with respect to the measurement point, the more preferable (for example, when the depression angle is 90°, the thermal camera 11 faces the sea surface and can receive more infrared rays radiated from the sea surface, resulting in the highest measurement accuracy). In this embodiment, in order to increase the depression angle of the thermal camera 11 with respect to the measurement point, the thermal camera 11 (camera device 10) is preferably installed at an altitude of 30 meters or more, and more preferably at an altitude of 100 meters or more. On the other hand, if the installation position of the thermal camera 11 is too high, the distance from the sea surface increases, so the thermal camera 11 is preferably installed at an altitude of 500 meters or less, and more preferably at an altitude of 300 meters or less. In addition, when installing the thermal camera 11, the depression angle with respect to the measurement point may be calculated, and the installation position of the thermal camera 11 may be determined so that the depression angle is 1.8° or more, preferably 2.5° or more.

[0014] Next, the control device 20 will be described. The control device 20 receives thermography and color image data transmitted from the thermal camera 11. The control device 20 also acquires sea surface temperatures at one or more measurement points from the thermography based on position information of each measurement point in the thermography and pre-stored camera information such as the camera's angle of view and lens size, and stores the sea surface temperatures at one or more measurement points in the memory unit of the control device 20. Note that, in order to reduce the processing load, the control device 20 can be configured to mask the part above the horizon (the part corresponding to the sky) and measure only the temperature of the part below the horizon (the part corresponding to the sea surface).

[0015] Here, it has been found that the sea surface temperature measured by the thermal camera 11 (hereinafter also referred to as the camera measurement value) fluctuates even within a relatively short period of time because the sea surface is swayed by waves, etc., and the incident light from the sea surface outside the measurement range increases and the incident light from the sea surface within the measurement range decreases. Therefore, in this embodiment, the control device 20 does not use the latest camera measurement value as the sea surface temperature, but calculates the moving average value of the most recent camera measurement values ​​as a provisional value for the sea surface temperature.

[0016] For example, the control device 20 sequentially receives thermography captured by the thermal camera 11 every second and stores it in the storage unit. Then, the control device 20 can calculate, for example, a moving average value of the camera measurement values ​​in the most recent 12 hours (a moving average value of 43,200 times when a thermography is captured every second) as a provisional value of the sea surface temperature. Note that the provisional value of the sea surface temperature described above is not limited to the moving average value of the camera measurement values ​​in the most recent 12 hours. For example, if it is not possible to obtain 43,200 pieces of sea surface temperature data as data of the camera measurement values ​​in the most recent 12 hours, it is possible to obtain 43,200 pieces of sea surface temperature data from data of sea surface temperatures measured within a maximum of 24 hours, and calculate the moving average value as the provisional value of the sea surface temperature. For example, if the thermal camera 11 captures a thermography every 2 seconds, it is possible to calculate the moving average value of the camera measurement values ​​in the most recent 24 hours (a moving average value of 43,200 times) as the provisional value of the sea surface temperature.

[0017] The control device 20 also has a correction function for correcting the provisional value of the sea surface temperature (moving average value of the camera measurement value) to bring it closer to the actual measurement value of the sea surface temperature. Here, FIG. 3 is a graph showing the relationship between the measurement value (hereinafter also referred to as the actual measurement value) of the sea surface temperature measured by actually contacting a contact thermometer with the sea surface and the camera measurement value of the sea surface temperature measured by the thermal camera 11. In the example shown in FIG. 3, the actual measurement value and the camera measurement value are measured twice, during the day and at night. As shown in FIG. 3, it was found that the camera measurement value of the sea surface temperature measured by the thermal camera 11 is about 7°C to 10°C lower than the actual measurement value of the sea surface temperature measured by the contact thermometer. In addition, as described later, it was found that the difference between the camera measurement value of the sea surface temperature measured by the thermal camera 11 and the actual measurement value of the sea surface temperature varies depending on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point, and the sea surface temperature.

[0018] Therefore, the control device 20 according to this embodiment calculates a correction value for correcting the provisional value of the sea surface temperature (moving average value of the camera measurement values) as follows. Specifically, the control device 20 calculates a correction value for correcting the provisional value of the sea surface temperature by adding (1) a reference correction value for reducing the difference between the measurement value of the sea surface temperature measured by the thermal camera 11 and the actual measurement value of the sea surface temperature measured by a contact thermometer, (2) a first adjustment value based on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point, and (3) a second adjustment value based on the sea surface temperature at the measurement point.

[0019] Here, the reference correction value is not particularly limited, and can be set appropriately by comparing the camera measurement value of the sea surface temperature measured by the thermal camera 11 with the actual measurement value of the sea surface temperature actually measured by a contact thermometer, as shown in Fig. 3. For example, in the example shown in Fig. 3, the camera measurement value of the sea surface temperature measured by the thermal camera 11 is about 7°C to 10°C lower than the actual measurement value of the sea surface temperature, so the reference correction value can be set in advance to 7°C, but it is preferable to set it appropriately depending on the installation position of the thermal camera 11, etc.

[0020] In addition, the control device 20 calculates a first adjustment value for adjusting the correction value based on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point. FIG. 4 is a graph showing the relationship between the distance from the thermal camera 11 to the measurement point and the first adjustment value. The longer the distance from the thermal camera 11 to the measurement point or the smaller the depression angle of the thermal camera 11 with respect to the measurement point, the less light is incident from the measurement point to the thermal camera 11, so the measured temperature detected by the thermography tends to be lower. Therefore, as shown in FIG. 4, the control device 20 can be configured to calculate the first adjustment value to be larger so that the correction value becomes larger as the distance from the thermal camera 11 to the measurement point becomes larger. Similarly, although not shown, the control device 20 can be configured to store in advance a graph (relational expression) showing the relationship between the depression angle of the thermal camera 11 with respect to the measurement point and the first adjustment value, and calculate the first adjustment value based on the graph (relational expression) based on the depression angle of the thermal camera 11 with respect to the measurement point. The relationship between the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point and the first adjustment value changes depending on the installation position of the thermal camera 11, etc., so it is set in advance based on the camera measurement value and the actual measurement value and stored in the storage unit of the control device 20. This allows the control device 20 to calculate the first adjustment value based on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point. In the example shown in Fig. 4, a negative value is used to reduce the amount of correction because the standard correction value has a large amount of correction at distances closer than 600 m as a result of prior verification, but the first adjustment value can be set appropriately depending on the installation position of the thermal camera 11, etc. (It may be a positive value even at distances closer than 600 m.) In addition, when the distance from the thermal camera 11 to the measurement point is a certain distance or more, or the depression angle of the thermal camera 11 with respect to the measurement point is a predetermined angle or less, the effect of the distance or depression angle on the sea surface temperature becomes small.Therefore, for example, as shown in FIG. 4, when the distance from the thermal camera 11 to the measurement point is a certain distance or more (800 m or more in the example shown in FIG. 4), or when the depression angle of the thermal camera 11 with respect to the measurement point is a certain angle or less, the first adjustment value can be set to a certain value (for example, 0.1 in the example shown in FIG. 4).

[0021] Furthermore, the control device 20 calculates the second adjustment value based on the provisional value (moving average value of the camera measurement value) of the sea surface temperature at the measurement point measured by the thermal camera 11. FIG. 5 is a graph showing the relationship between the provisional value of the sea surface temperature and the second adjustment value. In a preliminary verification, it was found that the higher the camera measurement value of the sea surface temperature measured by the thermal camera 11, the larger the difference between the camera measurement value of the sea surface temperature and the actual measurement value of the sea surface temperature tends to be. Therefore, in this embodiment, as shown in FIG. 5, the control device 20 calculates a second adjustment value for adjusting the correction value so that the correction value is set higher as the provisional value of the sea surface temperature at the measurement point measured by the thermal camera 11 is higher. Specifically, the second adjustment value for each provisional value of the sea surface temperature is obtained in advance from the relationship between the provisional value and the actual measurement value of the sea surface temperature at a certain measurement point, and the relationship between the provisional value of the sea surface temperature and the second adjustment value is stored in the storage unit. This allows the control device 20 to calculate the second adjustment value based on the provisional value of the sea surface temperature at the measurement point measured by the thermal camera 11. Note that the relationship between the provisional value of the sea surface temperature and the second adjustment value can be calculated based on a graph (table) as shown in Fig. 5, or a linear equation that approximates the relationship between the provisional value of the sea surface temperature and the second adjustment value can be calculated and the second adjustment value can be calculated based on the linear equation.

[0022] Then, the control device 20 adds the calculated first adjustment value and second adjustment value to a preset correction reference value, as shown in the following formula, to calculate a correction value for correcting the provisional value of the sea surface temperature (the moving average value of the camera measurement values). Correction value = correction reference value + 1st adjustment value + 2nd adjustment value Furthermore, the control device 20 corrects the provisional value of the sea surface temperature by adding the above correction value to the provisional value of the sea surface temperature as shown in the following formula. Sea surface temperature = Provisional sea surface temperature + Correction value In addition, the control device 20 calculates a provisional value and a corrected value of the sea surface temperature for each measurement point, thereby calculating the sea surface temperature at each measurement point and storing the calculated values ​​in the memory unit of the control device 20.

[0023] Furthermore, the control device 20 according to this embodiment has a function of detecting a sign of the Kyucho phenomenon based on the sea surface temperature (corrected sea surface temperature) at each measurement point. Here, FIG. 6 is a diagram for explaining an example of a method for detecting a sign of the Kyucho phenomenon according to this embodiment. The control device 20 first reads out the time series data of the sea surface temperature at each measurement point stored in the storage unit. Then, the control device 20 detects a sign of the Kyucho phenomenon based on the time series data of the sea surface temperature. Here, it is known that a relatively steep rise in sea surface temperature is a sign of the Kyucho phenomenon. Therefore, as shown in FIG. 6, the control device 20 calculates the average value A of the sea surface temperature for the previous 24 hours and the average value B of the most recent sea surface temperature (for example, the average value B of the most recent sea surface temperature for the most recent 30 minutes), and if the average value A of the sea surface temperature for the previous day is 3° C. or more higher than the average value A of the sea surface temperature for the previous day, it outputs information to that effect that there is a sign of the Kyucho phenomenon. The average value of the sea surface temperature for the previous day can be calculated just after midnight every day and stored in the memory unit of the control device 20.

[0024] 1, the control device 20 is connected to a monitor 40, and can output color images captured by the color camera unit of the thermal camera 11 and warnings when signs of a kyucho phenomenon are detected to the display of the monitor 40. The control device 20 is also connected to a terminal device 50 such as a personal computer, and through the terminal device 50, an administrator can control the thermal camera 11, monitor the sea surface temperature measured by the thermal camera 11 and corrected by the control device 20, and monitor illegal fishing boats and the like based on the color images captured by the thermal camera 11.

[0025] Furthermore, the control device 20 can also connect to a remote communication terminal 60 via a communication line such as an Internet line, and like the terminal device 50, can monitor for signs of a kyutyo phenomenon, illegal fishing boats, and the like even from the remote communication terminal 60. In addition, the control device 20 can connect to a mobile terminal 70 such as a smartphone via a communication line such as a telephone communication line or an Internet line, and can send a warning to the mobile terminal 70 by email or the like when a sign of a kyutyo phenomenon is detected, for example. EXAMPLES

[0026] Next, an embodiment of the present invention will be described. In this embodiment, one thermal camera 11 was used to measure the sea surface temperature at nine measurement points, the distances from the thermal camera 11 being 300 m, 500 m, 600 m, 800 m, 1000 m, 1500 m, 2000 m, 2500 m, and 3000 m, as camera measurement values. In addition, at the same nine measurement points, the sea water temperature was measured as an actual measurement value using a contact thermometer. In this embodiment, the measurement of the sea surface temperature using the thermal camera 11 and the measurement of the sea water temperature using a contact thermometer were performed twice. In this embodiment, the thermal camera 11 was a twin-lens thermal camera (model number DK-TPV-IAHDR35H) manufactured by Denki Kogyo Co., Ltd., which was installed at an altitude of approximately 120 m above sea level and measurements were performed. The measurement results are shown in Table 1 and FIG. 7 below. FIG. 7 is a graph showing the actual measurement value, the provisional value of the sea surface temperature (the moving average value of the camera measurement value), the temperature difference between the actual measurement value and the provisional value of the sea surface temperature, and the corrected sea surface temperature in this embodiment. [Table 1]

[0027] In this embodiment, the provisional sea surface temperature values ​​(1) and (2) indicate the moving average values ​​of the camera measurement values ​​for the most recent 12 hours measured by the thermal camera 11. The temperature difference between the provisional sea surface temperature value and the actual measurement value is calculated as (actual measurement value (1) + average of actual measurement value (2)) - (provisional sea surface temperature value (1) + average of provisional sea surface temperature value (2)).

[0028] As shown in Table 1 and FIG. 7, there was a temperature difference of about 6 to 8°C between the actual sea surface temperature measured by the contact thermometer and the provisional sea surface temperature based on the measurement results of the thermal camera 11. Therefore, in this embodiment, the control device 20 calculates a correction value for correcting the provisional sea surface temperature in order to reduce such a temperature difference. Specifically, the control device 20 first acquires a preset reference correction value from the storage unit. In this embodiment, the reference correction value is set to 7°C, so the control device 20 can acquire the reference correction value as 7°C.

[0029] In addition, the control device 20 calculates a first adjustment value for adjusting the correction value based on the relationship with the first adjustment value based on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point, as shown in Fig. 4. In this embodiment, the distance from the thermal camera 11 to the measurement point and the first adjustment value are set as shown in Table 2 below, as follows: -1.2°C at 300m, -0.7°C at 500°C, 0°C at 600m, and 0.1°C at 800 to 3000m. Table 2 is a graph showing the reference correction value, the first adjustment value, the second adjustment value, and the correction value in this embodiment. [Table 2]

[0030] Furthermore, the control device 20 calculates a second adjustment value based on the sea surface temperature. In this embodiment, the control device 20 stores y=0.2729x-1.279 (where y is the second adjustment value and x is the provisional value of the sea surface temperature) as a linear function approximating the camera measurement value of the sea surface temperature and the second adjustment value shown in the graph of Fig. 5, and calculates the second adjustment value using this. Note that in the example shown in Table 2, for ease of explanation, the second adjustment value is rounded off to one decimal place.

[0031] Then, the control device 20 calculates a correction value by summing the reference correction value, the first adjustment value, and the second adjustment value for each measurement point. In this embodiment, as shown in Table 2 above, the correction value calculated at 300 m is 6.4°C, the correction value at 500°C is 6.8°C, and the correction value at 600 m is 7.4°C.

[0032] Furthermore, the control device 20 calculates the sea surface temperature by adding the calculated correction value to the provisional value of the sea surface temperature, as shown in the following Table 3. In this embodiment, as shown in the following Table 3, the difference between the actual sea surface temperature measured by the contact thermometer and the corrected sea surface temperature was less than 1 degree at depths of 300 to 3000 m, and a temperature close to the actual sea surface temperature could be calculated. [Table 3]

[0033] As described above, in the Kyucho detection system 1 according to this embodiment, the sea surface temperature at multiple measurement points can be measured by the thermal camera 11 installed on land, which eliminates the need for expensive measurement buoys and is inexpensive, and since it is on land, maintenance is easy. On the other hand, when measuring the sea surface temperature using the thermal camera 11, there is a problem that an error occurs between the sea surface temperature measured by the thermal camera 11 and the actual sea surface temperature. In response to this, the Kyucho detection system 1 according to this embodiment calculates the moving average value of the camera measurement value of the sea surface temperature measured by the thermal camera 11 as the provisional value of the sea surface temperature, thereby making it possible to reduce the influence of fluctuations in the sea surface temperature due to fluctuations in the sea surface. In addition to the reference correction value, a first adjustment value based on the distance from the thermal camera 11 to the measurement point or the depression angle of the thermal camera 11 with respect to the measurement point, and a second adjustment value based on the sea surface temperature are added to correct the provisional value of the sea surface temperature, making it possible to calculate a sea surface temperature close to the actual sea surface temperature.

[0034] Moreover, the thermal camera 11 according to this embodiment has a color camera unit capable of capturing color images, and can transmit color images captured by the color camera unit to the control device 20. This allows, for example, an observer to access the control device 20 via the terminal device 50 and monitor video based on color images captured by the thermal camera 11, which can also monitor poaching boats, for example. Note that poaching boats can be monitored by analyzing captured images or by machine learning using ship images as teacher data, so that poaching boats can be automatically detected.

[0035] Although the preferred embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the description of the above embodiment. Various modifications and improvements can be made to the above embodiment, and such modifications and improvements are also included in the technical scope of the present invention.

[0036] For example, in the above embodiment, the thermal camera 11 has a thermal camera unit that captures thermography and a color camera unit that captures color images, but it may have only the thermal camera unit. Also, instead of the color camera unit, it may have a monochrome camera unit that captures monochrome images (or grayscale images, etc.).

[0037] In addition to the above-described embodiment, the correction value may be adjusted taking into account the weather, season, etc. For example, if the difference between the sea surface temperature measured by the thermal camera 11 and the actual measured value of the sea surface temperature changes depending on the weather or season, the correction value may be adjusted in advance by an amount according to the weather or season. Furthermore, it is also possible to accumulate sea surface temperature data for a relatively long period of time, such as measurement data from the Japan Meteorological Agency, and adjust the correction value based on the sea surface temperature data for each measurement point and each date. [Explanation of symbols]

[0038] 1. Kyucho detection system 10. Camera equipment 11…Thermal camera 12...Floodlight 13…Camera controller 14...Communication equipment 20...Control device 30…Internet connection 40…Monitor 50...Terminal device 60...Communication terminal 70…Mobile devices

Claims

1. 1. A method for continuous remote sensing of sea surface temperature using a rotatable thermal camera, comprising: a measuring step of measuring sea surface temperature at three or more points using the thermal camera; a correction value calculation step of calculating a correction value for correcting the sea surface temperature measured in the measurement step; a correction step of correcting the measured sea surface temperature based on the correction value calculated in the correction value calculation step and storing the corrected sea surface temperature in a storage device; a continuous measurement step of continuously executing the measurement step and the correction step, A method for continuous remote measurement of sea surface temperature, in which the correction value calculation process calculates the correction value for each measurement point by adjusting a predetermined standard correction value set in advance based on the magnitude of the sea surface temperature measured by the thermal camera at each measurement point.

2. A method for continuous remote measurement of sea surface temperature as described in claim 1, wherein in the correction value calculation process, the predetermined standard correction value is further adjusted based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point, thereby calculating the correction value for each measurement point.

3. 3. The method for continuous remote sensing of sea surface temperature according to claim 1, wherein in the correction step, the measured sea surface temperature is corrected after masking a portion above the horizon in the image captured by the thermal camera.

4. 4. The method for continuous remote sensing of sea surface temperature according to claim 1, wherein the continuous measuring step is performed while rotating the thermal camera in a horizontal direction.

5. 5. The method for continuous remote measurement of sea surface temperature according to claim 1, wherein in the correction value calculation step, the correction value is calculated by adding to the predetermined reference correction value a first adjustment value based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point, and a second adjustment value based on the sea surface temperature measured by the thermal camera.

6. An average temperature calculation step of calculating a daily average of the measured sea surface temperature; an alert step of issuing an alert indicating a sign of a kyucho phenomenon when an average value of the sea surface temperature calculated at the same measurement point has risen by a certain amount or more from the average value of the sea surface temperature of the previous day; 6. A method for continuous remote sensing of sea surface temperature according to claim 1, comprising:

7. 7. The method for continuous remote measurement of sea surface temperature according to claim 1, wherein the thermal camera is installed at an altitude of 30 m to 500 m above sea level.

8. 8. The method for continuous remote measurement of sea surface temperature according to claim 1, wherein the thermal camera measures the sea surface temperature at a measurement point at a distance of 100 m to 3000 m from the thermal camera.

9. 9. The method for continuous remote measurement of sea surface temperature according to claim 1, wherein the thermal camera is set to have a depression angle of 1.8 degrees or more.

10. A rotatable thermal camera that measures sea surface temperature at three or more points; A control unit that calculates a correction value for correcting the sea surface temperature measured by the thermal camera and corrects the sea surface temperature measured by the thermal camera based on the correction value, The control unit continuously measures the sea surface temperature by correcting the sea surface temperature continuously measured by the thermal camera with the correction value, The control unit calculates the correction value for each measurement point by adjusting a predetermined standard correction value based on the magnitude of the sea surface temperature measured by the thermal camera at each measurement point.

11. The continuous measurement system described in Claim 10, wherein the control unit calculates a correction value for each measurement point by further adjusting the specified standard correction value based on the distance from the thermal camera to the measurement point or the depression angle of the thermal camera relative to the measurement point.

12. The control unit calculates a daily average of the sea surface temperature measured by the thermal camera, and if the average value of the sea surface temperature calculated at the same measurement point is higher than a certain level from the average value of the sea surface temperature of the previous day, issues an alert indicating a sign of a kyucho phenomenon.

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