Measurement system, measurement method, and measurement program

Abstract

To provide a measurement system capable of reducing the complexity of setting length standards required for deriving the vegetation cover area of ​​a seaweed bed. [Solution] The measurement system measures the area of ​​the vegetation cover range of a seaweed bed using an unmanned small submersible or the like equipped with a camera, installs a length standard of a known length that is equipped on the unmanned small submersible or the like and is photographed together with the camera's subject to serve as an indicator of the size of the subject within the range of the camera's shooting, acquires a photograph of the seaweed bed using the camera with the length standard installed within the camera's range of shooting as image information, and performs image analysis processing on the image information to extract the vegetation cover range within a specified range in the photographed image from the image information, calculates the proportion of the vegetation cover range within the specified range that it occupies to the specified range as the coverage, calculates the area of ​​the specified range based on the length standard included in the photographed image, and calculates the area of ​​the vegetation cover range within the specified range based on the coverage and the area of ​​the specified range.

Description

[Technical field]

[0001] The present invention relates to a measurement system, a measurement method, and a measurement program, and in particular to a measurement system, a measurement method, and a measurement program suitable for measuring the area of ​​vegetation coverage in a seaweed bed, where the ground surface is covered by plants. [Background technology]

[0002] Blue carbon is being promoted as an effective option for combating global warming, and research into blue carbon ecosystems is being conducted. Blue carbon is carbon that is absorbed from the atmosphere by marine organisms and stored in the ocean. Examples of blue carbon ecosystems include seagrass beds and seaweed beds. One example of a blue carbon ecosystem survey is to measure the vegetation cover area of ​​the seaweed beds being surveyed. Vegetation cover area refers to the area of ​​the ground that is covered by plants.

[0003] Conventionally, the measurement of vegetation cover has been done by setting up a rectangular frame of a given size (for example, 1m x 1m) called a quadrat and roughly judging the vegetation cover area by visually checking against the size of the quadrat. However, because this was done visually by checking against the size of the quadrat, it was not easy to measure the vegetation cover area accurately. Furthermore, although a certain degree of accuracy could be guaranteed by using the seaweed and seagrass coverage classification recommended by the Fisheries Agency, there was still the problem that visual checking could lead to individual differences. In addition, the coverage class of seaweed and seagrass refers to a class set for each category that is determined by dividing the coverage (%) into specified ranges. For example, a coverage of less than 5% is Class 1, a coverage of 5-25% is Class 2, etc.

[0004] In response, a method has been proposed in which the growth conditions of algae are acquired from images of the seaweed bed, and the area of ​​the seaweed bed is calculated by a computer (see, for example, Patent Document 1). The seaweed bed evaluation device disclosed in Patent Document 1 is realized by a device such as a personal computer, a server, a smartphone, a tablet computer, or an industrial computer, and acquires the growth conditions of algae from images of the seaweed bed, and derives the area of ​​the seaweed bed based on the acquired growth conditions of the algae. However, Patent Document 1 does not disclose a specific method by which the seaweed bed evaluation device derives the area of ​​the seaweed bed from an image of the seaweed bed.

[0005] Quadrats, which are used as a length standard when calculating the vegetation cover area from images of seaweed beds, are still cumbersome and require people to dive underwater to set them up. Therefore, the emergence of technology that can reduce the complication of setting length standards required to derive the vegetation cover area in seaweed beds has been desired. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2023-135742 A Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a measurement system, a measurement method, and a measurement program that can reduce the complexity of setting length standards required to derive the vegetation cover area in a seaweed bed. [Means for solving the problem]

[0008] In other words, the measurement system of the first aspect is a measurement system that measures the area of ​​vegetation cover range where plants cover the surface of a seaweed bed using an unmanned small submersible or unmanned small surface boat equipped with a camera, and is characterized by comprising: a length standard installation unit that is provided on the unmanned small submersible or unmanned small surface boat and installs, within the camera's shooting range, a length standard of a known length that is photographed together with the camera's subject to serve as an indicator of the size of the subject; an image information acquisition unit that acquires, as image information, an image of the seaweed bed photographed using the camera with the length standard installed within the camera's shooting range; a vegetation cover range extraction unit that extracts the vegetation cover range within a specified range of the photographed image from the image information by performing image analysis processing on the image information; a coverage calculation unit that calculates the ratio of the vegetation cover range within the specified range to the specified range as coverage; a specified range area calculation unit that calculates the area of ​​the specified range based on the length standard included in the photographed image; and a vegetation cover range area calculation unit that calculates the area of ​​the vegetation cover range within the specified range based on the coverage and the area of ​​the specified range.

[0009] In a second aspect, in the measurement system according to the first aspect, the length reference installation unit gives instructions to a laser light emitting device mounted on an unmanned small submarine or an unmanned small surface boat, the laser light emitting device has a pair of laser light emission ports, the laser light emitted from each of the pair of emission ports is parallel, the distance between the pair of emission ports is known, the laser light is a pointing laser or a line laser, the length reference is the distance between the irradiation positions of the pair of laser light irradiated from the pair of emission ports toward the ground's surface, and the specified range area calculation unit calculates the area of ​​the specified range in the captured image based on the distance between the irradiation positions of the pair of laser light in the captured image.

[0010] In a third aspect, in the measurement system according to the first aspect, the length standard may be a quadrat of a known size, and the length standard installation unit may install the quadrat on the ground within the shooting range of the camera.

[0011] In a fourth aspect, in the measurement system of the second aspect, the unmanned small submersible or unmanned small surface watercraft may further include an attitude angle sensor that measures an attitude angle of the unmanned small submersible or unmanned small surface watercraft, and a length reference correction unit that corrects a length reference included in a captured image according to the attitude angle at the time of shooting by the camera.

[0012] In a fifth aspect, in the measurement system according to the first aspect, the vegetation coverage range extraction unit may extract the vegetation coverage range from the captured image by performing image analysis processing on the image information using image segmentation.

[0013] The sixth aspect may be such that the measurement system according to the second aspect further includes an irradiation position detection unit that detects the irradiation position of the pair of laser beams in the captured image, and a separation distance measurement unit that measures the separation distance between the irradiation positions of the pair of laser beams.

[0014] A measurement method according to a seventh aspect is a measurement method used in a measurement system that uses an unmanned small submersible or unmanned small surface boat equipped with a camera to measure the area of ​​vegetation cover range where plants cover the surface of a seaweed bed, and the measurement system is characterized by executing the following steps: a length standard installation step, which is provided on the unmanned small submersible or unmanned small surface boat, and which installs, within the shooting range of the camera, a length standard having a known length that serves as an indicator of the standard for the size of the subject when photographed together with the subject of the camera; an image information acquisition step, which acquires, as image information, an image of the seaweed bed photographed using the camera with the length standard installed within the shooting range of the camera; a vegetation cover range extraction step, which extracts from the image information the vegetation cover range within a specified range of the photographed image by performing image analysis processing on the image information; a coverage calculation step, which calculates the ratio of the vegetation cover range within the specified range to the specified range as the coverage; a specified range area calculation step, which calculates the area of ​​the specified range based on the length standard included in the photographed image; and a vegetation cover range area calculation step, which calculates the area of ​​the vegetation cover range within the specified range based on the coverage and the area of ​​the specified range.

[0015] The measurement program of the eighth aspect is a measurement program used in a measurement system that uses an unmanned small submersible or unmanned small surface boat equipped with a camera to measure the area of ​​vegetation cover range where plants cover the surface of a seaweed bed, and is characterized in that the measurement system realises the following: a length standard installation function that is provided on the unmanned small submersible or unmanned small surface boat and installs, within the camera's shooting range, a length standard of a known length that is photographed together with the camera's subject to serve as an indicator of the size of the subject; an image information acquisition function that acquires, as image information, an image of the seaweed bed photographed using the camera with the length standard installed within the camera's shooting range; a vegetation cover range extraction function that extracts the vegetation cover range within a specified range of the photographed image from the image information by performing image analysis processing on the image information; a coverage calculation function that calculates the ratio of the vegetation cover range within the specified range to the specified range as the coverage; a specified range area calculation function that calculates the area of ​​the specified range based on the length standard included in the photographed image; and a vegetation cover range area calculation function that calculates the area of ​​the vegetation cover range within the specified range based on the coverage and the area of ​​the specified range. Effect of the Invention

[0016] The measurement system according to the present invention is a measurement system for measuring the area of ​​vegetation coverage in a seaweed bed, where the surface area is covered by plants, using an unmanned small submersible or unmanned small surface water boat equipped with a camera, and includes a length standard installation unit that is provided on the unmanned small submersible or unmanned small surface water boat and installs, within the shooting range of the camera, a length standard having a known length that serves as an index showing the standard size of the subject when photographed together with the subject of the camera; an image information acquisition unit that acquires, as image information, an image of the seaweed bed photographed with the camera with the length standard installed within the shooting range of the camera; By performing image analysis processing, the system is characterized by being equipped with a vegetation cover range extraction unit that extracts the vegetation cover range within a specified range of the captured image from the image information, a coverage calculation unit that calculates the ratio of the vegetation cover range within the specified range to the specified range as coverage, a specified range area calculation unit that calculates the area of ​​the specified range based on a length standard included in the captured image, and a vegetation cover range area calculation unit that calculates the area of ​​the vegetation cover range within the specified range based on the coverage and the area of ​​the specified range, thereby reducing the complexity of setting length standards required to derive the vegetation cover area in a seaweed bed.

[0017] Furthermore, like the measurement system of the present invention, the measurement method and measurement program of the present invention can reduce the complexity of setting length standards required to derive the vegetation cover area in a seaweed bed. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram for explaining an example of a hardware configuration of a measurement system according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of an unmanned small submarine used in the first embodiment of the present disclosure. [Diagram 3] FIG. 3 is a diagram showing an example of the configuration of an unmanned small submarine used in the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram for explaining an example of a procedure of an image analysis process performed by the measurement system according to the first embodiment of the present disclosure. [Diagram 5]FIG. 5 is a block diagram for explaining an example of a functional configuration of the measurement system according to the first embodiment of the present disclosure. [Figure 6] Figure 6 is a diagram to explain the coverage classes of seaweed and seagrass. [Figure 7] FIG. 7 is a diagram for explaining a first modified example of the unmanned mini submarine used in the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram for explaining a second modified example of the unmanned mini submarine used in the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of an unmanned mini-submersible vehicle used in the second embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram showing an example of the configuration of an unmanned mini-submersible vehicle used in the second embodiment of the present disclosure. [Figure 11] FIG. 11 is an example of a flowchart of a measurement program according to an embodiment of the present disclosure. [Figure 12] FIG. 12 is an example of a flowchart of a measurement program according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (Regarding the first embodiment of the present disclosure) A measurement system 10 and an unmanned mini submersible 20 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. FIG. Furthermore, the measurement system 10 may use an unmanned small surface boat (not shown) instead of the unmanned small submarine boat 20, and this case will also be described below. The measurement system 10 measures the area of ​​the vegetation cover range where plants cover the ground surface in a seaweed bed 46 (see FIG. 4) using an unmanned small submersible 20 or an unmanned small surface boat (not shown) equipped with a forward-facing camera 22. Measurement of the coverage and vegetation area of ​​a seaweed bed 46 using the measurement system 10 according to the first embodiment of the present disclosure is performed at a representative point (fixed monitoring point) in the seaweed bed 46 being surveyed, unlike the wide-area, surface-level assessment used in wide-area seaweed bed monitoring to investigate the presence or absence of a seaweed bed. It is desirable that the representative point in the seaweed bed 46 is a representative point where the growth status of seaweed / seagrass 39 (see FIG. 4) can be grasped. Furthermore, the measurement of the coverage and vegetation area of ​​the seaweed bed 46 using the measurement system 10 according to the first embodiment of the present disclosure is not limited to a representative point (fixed monitoring point) in the surveyed seaweed bed 46, but various methods and applications are envisioned. For example, the measurement system 10 according to the first embodiment of the present disclosure may be used to measure the coverage and vegetation area of ​​the entire range of a small-scale seaweed bed 46.

[0020] (Hardware configuration of the measurement system 10 according to the first embodiment) An example of a hardware configuration of the measurement system 10 will be described with reference to Fig. 1. Fig. 1 is a block diagram for explaining an example of a hardware configuration of the measurement system 10. The measurement system 10 is a so-called computer and can be realized by a server, a personal computer (hereinafter referred to as PC), a notebook PC, a tablet PC, a smartphone, etc., and is equipped with a communication interface 10a, a ROM (Read Only Memory) 10b, a RAM (Random Access Memory) 10c, a memory unit 10d, a processing unit 10e, and an input / output interface 10f, etc.

[0021] The communication interface 10a has a function of transmitting and receiving data handled by the measurement system 10 with other devices via wired communication or wireless communication. The measurement system 10 may be connected to an information and communication network 15 via the communication interface 10a, and may transmit and receive data with other devices via the information and communication network 15. When the measurement system 10 is connected to other devices via Bluetooth (registered trademark), the communication interface 10a is a Bluetooth interface, and when the measurement system 10 is connected to other devices via wireless LAN, the communication interface 10a is a wireless LAN interface. The other device may be the unmanned mini submersible vehicle 20 or the unmanned mini surface vehicle (not shown), etc. The unmanned mini submersible vehicle 20 and the unmanned mini surface vehicle are operated by a dedicated controller (not shown), but may be operated according to a program designed in advance by the measurement system 10.

[0022] The memory unit 10d can be used as a storage device for the measurement system 10 and is composed of, for example, a hard disk drive, a solid state drive, and a flash memory, and the memory unit 10d can also be configured using cloud storage. The storage unit 10d of the measurement system 10 stores a measurement program (to be described later), an OS (Operating System) required for the measurement system 10 to operate, various other applications, and various data used by the applications.

[0023] The processing unit 10e includes a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphic Processing Unit), etc., and is realized by a logic circuit or a dedicated circuit formed by an integrated circuit (IC (Integrated circuit) chip, LSI (Large-Scale Integration)), etc.

[0024] The measurement system 10 stores a measurement program, which will be described later, in a ROM 10b or a storage unit 10d, and loads the measurement program into a main memory constituted by a RAM 10c, etc. The processing unit 10e accesses the main memory into which the measurement program has been loaded, and executes the measurement program.

[0025] The input / output interface 10f transmits and receives data to and from devices external to the measurement system 10. The external devices refer to an input device 11 and an output device 12 that input and output data to and from the measurement system 10. The input device 11 is, for example, a forward-facing camera 11a, an attitude angle sensor 11b, a keyboard, and a mouse, while the output device 12 is, for example, a laser light emitting device 12a, a monitor, a printer, and a speaker. The forward-facing camera 11a and the attitude angle sensor 11b are mounted on the unmanned small submersible boat 20 or the unmanned small surface boat. The attitude angle sensor 11b may be an inertial measurement unit (IMU), which uses a three-axis gyro and a three-directional accelerometer to determine three-dimensional angular velocity and acceleration.

[0026] (Configuration of the unmanned mini submarine 20 according to the first embodiment) An example of the configuration of the unmanned mini submarine 20 will be described with reference to Figures 2 and 3. Figures 2 and 3 are diagrams showing an example of the configuration of the unmanned mini submarine 20. Figure 3(a) is a plan view of the unmanned mini submarine 20 as seen from above, and Figure 3(b) is a front view of the unmanned mini submarine 20 as seen from the front. The unmanned mini-submersible vehicle 20 is a small unmanned aircraft capable of diving and navigating underwater, and is also called an underwater drone or an ROV (Remotely Operated Vehicle). The unmanned mini-submersible vehicle 20 can be remotely controlled from land or a ship, and real-time images captured by the mounted forward-facing camera 22 can be viewed. The unmanned small submersible 20 may also be an autonomous underwater vehicle (AUV). An autonomous unmanned submersible does not require remote operation, and can dive and navigate toward a preset destination or along a route by autonomously judging the situation. The unmanned mini submarine 20 is equipped with eight screws called thrusters 26, which enable horizontal movement in all directions, as well as rotation in the pitch direction and roll direction to change the angle of the body 21, allowing it to move freely within a specified angle range. Note that this specified angle range differs depending on the model used for the unmanned mini submarine 20; some models can move freely 360 degrees, while other models can move freely within an angle range less than 360 degrees. The unmanned mini submarine 20 is powered by being connected to a power supply cable 25, but is not limited to this. It can also be equipped with a battery (not shown) and powered by the power from the battery.

[0027] The unmanned mini-submersible vehicle 20 is equipped with a forward-facing camera 22, forward-facing illumination ports 23 and 24, and a forward-facing light 27 at the forward tip of the body 21 (see Figures 2 and 3(a)). The forward-facing camera 22 is used to capture images in the forward direction of the aircraft 21. The forward irradiation ports 23, 24 irradiate forward laser beams 23a, 24a, which are the pointing laser of the laser beam irradiation device 12a, in parallel with each other in the forward direction of the airframe 21. The forward laser beams 23a, 24a may be parallel to the optical axis of the imaging direction of the forward camera 22, or may be parallel to the overall length direction 21a of the airframe 21 (see FIG. 3(a)). A pointing laser is a type of laser light in which the shape of the light formed at the irradiation position when the laser energy hits an object is a point. The laser light used is a green laser, but it is not limited to this and may be a red laser. Green lasers are brighter than red lasers and have high visibility, especially underwater, outdoors, and in bright places. When the camera (forward camera 22, downward camera 30) is taking an image, if the water is murky and the visibility of the irradiation position of the laser light is poor due to low visibility, the laser light may be made to blink in order to improve visibility. Also, the power consumption required for irradiating the laser light may be reduced by adjusting the blinking speed of the laser light or the output of the laser light according to the visibility of the water when the camera (forward camera 22, downward camera 30) is taking an image. A distance 23c between the forward-facing irradiation port 23 and the forward-facing irradiation port 24 is a previously set known value. The forward laser beam 23a emitted from the forward irradiation port 23 and the forward laser beam 24a emitted from the forward irradiation port 24 are parallel to each other. Irradiation position 23b is the position where forward laser beam 23a is incident on earth's surface 38. Irradiation position 24b is the position where forward laser beam 24a is incident on earth's surface 38. Distance 24c between irradiation position 23b and irradiation position 24b is a length reference described below, and in order to match distance 23c, which is a known length, it is desirable for forward laser beams 23a, 24a to be incident perpendicularly to ground surface 38. Since forward irradiation ports 23, 24 irradiate forward laser beams 23a, 24a parallel to overall length direction 21a of airframe 21, airframe 21 is controlled to be perpendicular to ground surface 38 when irradiating forward laser beams 23a, 24a. This control is performed based on the attitude angle of airframe 21 measured by attitude angle sensor 11b. In addition, forward-facing light 27 is used to illuminate the subject of forward-facing camera 22 when, for example, the illumination is insufficient when forward-facing camera 22 takes a photograph.

[0028] Furthermore, the unmanned mini-submersible vehicle 20 is equipped with a downward camera 30, downward illumination ports 35, 36, and a downward light (not shown) on the bottom of the body 21 (see FIG. 3(b)). The downward camera 30 is used to capture images directly below the vehicle 21. If the attitude angle of the unmanned mini submarine 20 can be controlled using the attitude angle sensor 11b, it is not essential to install the downward camera 30. In other words, instead of using the downward camera 30, the attitude angle of the unmanned mini submarine 20 may be changed and the forward camera 22 may be used. The downward irradiation ports 35, 36 irradiate downward laser beams 35a, 36a, which are pointing lasers of the laser beam irradiation device 12a, in a downward direction parallel to the height direction 21b of the body 21. A distance 35c between the downward irradiation port 35 and the downward irradiation port 36 is a previously set known value. The downward laser light 35a emitted from the downward irradiation port 35 and the downward laser light 36a emitted from the downward irradiation port 36 are parallel to each other. Irradiation position 35b is the position where downward laser beam 35a is incident on earth's surface 38. Irradiation position 36b is the position where downward laser beam 36a is incident on earth's surface 38. A distance 36c between irradiation positions 35b and 36b is a length reference, which will be described later, and in order to match the distance 35c, which is a known length, it is desirable for the downward laser beams 35a, 36a to be incident perpendicularly to the ground surface 38. The downward irradiation ports 35, 36 irradiate the downward laser beams 35a, 36a in a direction directly below and parallel to the height direction 21b of the airframe 21, so that the airframe 21 is controlled to be parallel to the ground surface 38 when irradiating the downward laser beams 35a, 36a. This control is performed based on the attitude angle of the airframe 21 measured by the attitude angle sensor 11b. In addition, a downward light (not shown) is used to shine light on the subject of the downward camera 30 when, for example, the illumination intensity is insufficient when the downward camera 30 takes a picture.

[0029] (Configuration of the unmanned small surface boat according to the first embodiment) An unmanned small surface vessel is a small unmanned vessel (Unmanned Surface Vehicle: USV) that can navigate the sea unmanned, and is also called a water drone. An unmanned small surface vessel can be remotely controlled from land or a ship, and can navigate autonomously using position information obtained from the Global Positioning System (GPS). The unmanned small surface boat, like the unmanned small submarine boat 20, is equipped with a laser light irradiation device 12a. The unmanned small surface boat is equipped with a forward-facing camera 22, forward-facing illumination ports 23, 24, and a forward-facing light 27 at the bow, similar to the unmanned small submarine boat 20. The forward-facing camera 22 is used to capture images of the forward direction of the unmanned small surface boat in water. In addition, the unmanned small surface boat is equipped with a downward camera 30, downward illumination ports 35, 36, and a downward light (not shown) on the bottom of the boat, similar to the unmanned small submarine boat 20. The downward camera 30 is used to take pictures directly below the unmanned small surface boat.

[0030] (Regarding image analysis processing of the measurement system 10) Steps 1 to 3, which are an example of the procedure of the image analysis process performed by the measurement system 10, will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining the example of the procedure of the image analysis process performed by the measurement system 10. Image analysis processing is performed on captured images 37 of seaweed beds 46 in the ocean 45 acquired by the unmanned small submarine 20 and the cameras (forward-facing camera 22, downward-facing camera 30) mounted on the unmanned small surface boat.

[0031] Step 1 (see Figure 4(a)) With laser light (forward laser light 23a, 24a or downward laser light 35a, 36a: see FIG. 3) projected from the unmanned small submarine vehicle 20 and the unmanned small surface vehicle onto the surface 38 of the seaweed bed 46, the seaweed bed 46 is photographed by a camera (forward camera 22 or downward camera 30: see FIG. 3) to obtain a photographed image 37 as image information. In the photographed image 37, the projection positions 40, 41 of the laser light (forward laser light 23a, 24a or downward laser light 35a, 36a), the surface 38, and seaweed / sea grass 39 are imaged (visualized). An image information acquisition unit 61, which is a functional unit of the measurement system 10 and will be described later, acquires the captured image 37 from the camera (the forward-facing camera 22 or the downward-facing camera 30) as image information.

[0032] Step 2 (see Figure 4(b)) By performing image analysis processing on the image information acquired by the image information acquisition unit 61, the irradiation positions 40, 41 of the laser light (forward laser light 23a, 24a or downward laser light 35a, 36a: see Figure 3) are identified, and the number of pixels corresponding to the separation distance 42 between the irradiation positions 40, 41 is compared with the separation distance (separation distance 23c or separation distance 35c: see Figure 3) between the irradiation ports (forward irradiation ports 23, 24 or downward irradiation ports 35, 36: see Figure 3) of the laser light (forward laser light 23a, 24a or downward laser light 35a, 36a) to calculate the actual length corresponding to one pixel, and the scale, which is an index showing the standard for the size of the subject in the captured image 37, is grasped. Scale indicates the relationship between the actual length of an object in the photographed image 37 and the number of pixels on the photographed image 37. Specifically, the scale is expressed in the following manner. The scale of the photographed image 37 may be displayed, for example, as a scale bar 43 (see FIG. 4(c)) in the photographed image 37. The scale bar 43 indicates what the length on the photographed image 37 corresponds to in reality, and the scale bar 43 shown in FIG. 4(c) corresponds to 50 cm, but is not limited to this, and the length indicated by the scale bar 43 differs depending on the magnification (scale) on the photographed image 37. The presence of the scale bar 43 makes it possible to accurately know the magnification (scale) on the photographed image 37. In addition, the area of ​​the range contained in the captured image 37 can be calculated based on the actual length equivalent to one pixel on the captured image 37, and for example, the area of ​​an arbitrary rectangular range (for example, the entire range appearing in the captured image 37) set within the captured image 37, or an arbitrary shaped range set within the captured image 37 can be calculated. The irradiation positions 40 and 41 are identified by an irradiation position detection unit 64, which is a functional unit of the measurement system 10 and will be described later, and the number of pixels corresponding to the separation distance 42 is identified by a separation distance measurement unit 65, which will be described later.

[0033] Step 3 (see Figure 4(c)) Image analysis processing using image segmentation is performed on the image information of the photographed image 37 acquired by the image information acquisition unit 61, thereby extracting the vegetation cover range from the photographed image 37 and calculating the coverage of the seaweed bed 46 within the imaging range of the photographed image 37. In FIG. 4(c), the hatched area with black dots is the vegetation cover range extracted from the photographed image 37. Then, by multiplying the area of ​​the entire range captured in the photographed image 37 calculated in step 2 by the coverage of the photographed image 37, the area of ​​the range of the ground surface 38 covered by seaweed / sea grass 39 in the photographed image 37 can be calculated. Image segmentation is a technique for dividing a digital image into multiple image segments (image regions or image objects). More specifically, image segmentation is a technique for assigning a label to every pixel in an image such that pixels with the same label share certain characteristics. There are three types of image segmentation: semantic segmentation, instance segmentation, and panoptic segmentation, and each is used depending on the situation. Semantic segmentation is a method of classifying and identifying objects or regions contained in an image by labeling each pixel in the image with the object or region it belongs to. Instance segmentation is a technique that combines the characteristics of both object detection (detecting the individual positions) and semantic segmentation (detecting meaning at the pixel level). Panoptic segmentation is a combination of semantic and instance segmentation techniques that allows us to individually identify each object in an image and accurately delineate its boundaries. The vegetation coverage refers to the area of ​​the earth's surface 38 that is covered by seaweed and seagrass 39. In addition, the vegetation cover range is extracted from the captured image 37 by a vegetation cover range extraction unit 62, which is a functional unit of the measurement system 10, which will be described later, the coverage is calculated by a coverage calculation unit 63, which will be described later, the area of ​​the entire range appearing in the captured image 37 is calculated by a specified range area calculation unit 67, which will be described later, and the area of ​​the vegetation cover range, which is the range in the captured image 37 where the ground surface 38 is covered by seaweed / seagrass 39, is calculated by a vegetation cover range area calculation unit 68, which will be described later.

[0034] (Functional configuration of the measurement system 10) The functional configuration of the measurement system 10 will be described with reference to Fig. 5. Fig. 5 is a block diagram for explaining an example of the functional configuration of the measurement system 10. By executing the measurement program described below, the measurement system 10 is provided with functional units such as a length reference setting unit 60, an image information acquisition unit 61, a vegetation coverage range extraction unit 62, a coverage degree calculation unit 63, an irradiation position detection unit 64, a distance measurement unit 65, a length reference correction unit 66, a specified range area calculation unit 67, and a vegetation coverage range area calculation unit 68 in the processing unit 10e.

[0035] The length standard installation unit 60 is provided on the unmanned small submarine boat 20 and the unmanned small surface boat, and installs a length standard having a known length within the shooting range of the cameras (forward-facing camera 22, downward-facing camera 30) that is photographed together with the subject of the cameras (forward-facing camera 22, downward-facing camera 30) and serves as an indicator of the standard size of the subject. In this embodiment, the subject of the camera (forward-facing camera 22, downward-facing camera 30) refers to the seaweed bed 46 included in the camera's shooting range, including the seaweed and seagrass 39 included in the seaweed bed 46, the ground surface 38, the illumination positions 40, 41, and the distance 42 between the illumination positions 40, 41.

[0036] The length reference setting unit 60 issues instructions to the unmanned small submarine vessel 20 and the laser light emitting device 12a mounted on the unmanned small surface vessel. The laser light irradiator 12a is provided with a pair of irradiation ports (forward irradiation ports 23, 24 or downward irradiation ports 35, 36) for laser light. The laser light here refers to the forward laser light 23a, 24a or the downward laser light 35a, 36a. The pair of irradiation ports refers to the forward irradiation ports 23, 24 that serve as the irradiation ports for the forward laser light 23a, 24a, and the downward irradiation ports 35, 36 that serve as the irradiation ports for the downward laser light 35a, 36a. The forward laser beam 23a and the forward laser beam 24a are parallel, and the downward laser beam 35a and the downward laser beam 36a are parallel. The distance between the pair of irradiation ports, forward-facing irradiation port 23 and forward-facing irradiation port 24, is known, and the distance between the pair of irradiation ports, downward-facing irradiation port 35 and downward-facing irradiation port 36, is known. The forward laser beams 23a and 24a are either pointing lasers or line lasers. The forward laser beams 23a and 24a are the same type of laser beam, and are either pointing lasers or line lasers. The downward laser beams 35a and 36a are pointing lasers or line lasers, similar to the forward laser beams 23a and 24a. The downward laser beams 35a and 36a are the same type of laser beam, and are either pointing lasers or line lasers. When laser light is irradiated from the forward irradiation ports 23 and 24 as shown in FIG. 3(a), the length standard is the distance 24c between the irradiation positions 23b and 24b of a pair of laser light (forward laser light 23a and 24a) irradiated to the ground surface 38 from the pair of irradiation ports (forward irradiation ports 23 and 24). When laser light is irradiated from the downward irradiation ports 35 and 36 as shown in FIG. 3(b), the length standard is the distance 36c between the irradiation positions 35b and 36b of a pair of laser light (downward laser light 35a and 36a) irradiated to the ground surface 38 from the pair of irradiation ports (downward irradiation ports 35 and 36).

[0037] The image information acquisition unit 61 acquires, as image information, a captured image 37 of the seaweed bed 46 captured with the camera in a state where the length standard is set within the imaging range of the camera. When the forward-facing camera 22 is used as the camera, the length reference is the separation distance 24c (see FIG. 3(a)). When the downward-facing camera 30 is used as the camera, the length reference is the separation distance 36c (see FIG. 3(b)).

[0038] The vegetation cover range extraction unit 62 extracts the vegetation cover range within a predetermined range of the captured image 37 from the image information by performing image analysis processing on the image information. The vegetation coverage range extraction unit 62 extracts the vegetation coverage range from the captured image 37 by performing image analysis processing on the image information using image segmentation. The predetermined range is the entire range that appears in the photographed image 37, but is not limited to this, and any range within the photographed image 37 can be set.

[0039] The coverage calculation unit 63 calculates the ratio of the vegetation coverage area to the specified range within the specified range as the coverage area. The coverage calculation unit 63 calculates, as the coverage, the ratio of the vegetation coverage range extracted from the photographed image 37 by the vegetation coverage range extraction unit 62 to the entire range appearing in the photographed image 37, which is a predetermined range. An example of the calculation by the coverage calculation unit 63 will be described below with reference to FIG. The vegetation coverage range extracted from the photographed image 37 by the vegetation coverage range extraction unit 62 is the range hatched with black dots as shown in Fig. 4(c). The coverage calculation unit 63 calculates the coverage as the proportion of the range hatched with black dots to the entire range shown in the photographed image 37, which is a predetermined range.

[0040] The irradiation position detection unit 64 detects irradiation positions 40 and 41 of the pair of laser beams in the captured image 37 . The irradiation position detection unit 64 detects the positions of the irradiation positions 40 , 41 of the pair of laser beams included in the photographed image 37 by performing object detection of image analysis processing on the image information of the photographed image 37 . Object detection refers to detecting information such as the location, type, and number of specific objects from captured images or videos. Techniques used for object detection include, for example, a method using a convolutional neural network (CNN) and a method using YOLO (You Only Look Once).

[0041] The distance measuring unit 65 measures the distance between the irradiation positions 40, 41 of the pair of laser beams. The distance measuring unit 65 measures the number of pixels corresponding to the distance 42 between the irradiation positions 40 and 41 detected by the irradiation position detecting unit 64 . Since the separation distance 42 between the irradiation positions 40, 41 is a known value, the actual length corresponding to one pixel on the captured image 37 is calculated based on the number of pixels corresponding to the separation distance 42 measured by the separation distance measuring unit 65.

[0042] Length reference correction unit 66 corrects the length reference included in captured image 37 according to the attitude angle of the cameras (forward camera 22, downward camera 30) at the time of capturing the image. The unmanned mini submersible 20 is equipped with an attitude angle sensor 11b that measures the attitude angle of the unmanned mini submersible 20. Similarly, the unmanned small surface watercraft is equipped with an attitude angle sensor 11b that measures the attitude angle of the unmanned small surface watercraft. The length reference correction unit 66 corrects the length reference contained in the captured image 37 according to the attitude angles of the unmanned small submersible boat 20 and the unmanned small surface boat at the time of shooting by the cameras (forward camera 22, downward camera 30) measured by the attitude angle sensor 11b. When taking a picture with the camera (forward-facing camera 22, downward-facing camera 30), the attitude angle of the body 21 of the unmanned small submarine vehicle 20 or the unmanned small surface vehicle is controlled so that a pair of laser beams (23a, 24a, or 35a, 36a) emitted from a pair of illumination ports (23, 24, or 35, 36: see Figure 3) are incident perpendicularly to the ground surface 38. Therefore, when taking pictures using the forward-facing camera 22, the aircraft 21 is perpendicular to the ground surface 38, and when taking pictures using the downward-facing camera 30, the aircraft 21 is parallel to the ground surface 38. However, when taking pictures with the cameras (forward camera 22, downward camera 30), the attitude angle of the aircraft 21 may shift, and the reference length shifts according to the amount of this shift, so the length reference correction unit 66 corrects the length of the reference length according to the amount of this shift in the attitude angle.

[0043] The predetermined range area calculation unit 67 calculates the area of ​​the predetermined range based on the length standard included in the photographed image 37. The predetermined range area calculation unit 67 calculates the area of ​​a predetermined range in the photographed image 37 based on the separation distance 42 between the irradiation positions 40 and 41 of the pair of laser beams in the photographed image 37 . Since separation distance 42 is a known value, an actual length equivalent to one pixel on photographed image 37 is calculated based on the number of pixels equivalent to separation distance 42 measured by separation distance measurement unit 65. Predetermined range area calculation unit 67 calculates the area of ​​a predetermined range in photographed image 37 based on the actual length equivalent to one pixel on photographed image 37. Since the predetermined range in the photographed image 37 is the area of ​​the entire range appearing in the photographed image 37 , the predetermined range area calculation unit 67 calculates the area of ​​the entire range appearing in the photographed image 37 .

[0044] The vegetation coverage area calculation unit 68 calculates the area of ​​the vegetation coverage area within the specified range based on the coverage and the area of ​​the specified range. The vegetation coverage area calculation unit 68 calculates the area of ​​the vegetation coverage range within the specified range based on the coverage calculated by the coverage calculation unit 63 and the area of ​​the specified range calculated by the specified range area calculation unit 67. Since the area of ​​the entire range captured in the photographed image 37 is set as the specified range, the vegetation coverage area calculation unit 68 calculates the area of ​​the vegetation coverage range within the entire range captured in the photographed image 37.

[0045] The coverage classes of seaweed and seagrass 39 will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining the coverage classes of seaweed and seagrass 39. The coverage classes of seaweed and seagrass 39 are the measurement standards used when visually measuring the coverage of seaweed and seagrass 39. In detail, the coverage classes of seaweed and seagrass 39 are divided into five categories based on the percentage (%) of the vegetation area of ​​seaweed and seagrass 39 within the quadrat 28, with coverage of less than 5% being class 1, coverage of 5-25% being class 2, coverage of 25-50% being class 3, coverage of 50-75% being class 4, and coverage of 75-100% being class 5, and photographs of the seaweed beds 46 corresponding to each class are posted. A visual observer selects from the photographs corresponding to each seaweed / seagrass39 coverage class the one that most closely resembles the photograph taken in the seaweed bed46 to be measured. Therefore, measurements of coverage and vegetation area using the coverage classes of seaweed and seagrass 39 can only provide rough measurement results without specific numerical values, and cannot be performed with high accuracy. Furthermore, since the measurement is performed visually, a certain degree of accuracy can be ensured, but the problem of individual differences in measurement results has not been resolved. In contrast, according to the measurement system 10 of the first embodiment, the vegetation coverage range can be accurately extracted from the captured image 37 by performing image analysis processing on the image information using image segmentation, and therefore the coverage degree and vegetation coverage area can also be accurately calculated as specific numerical values.

[0046] (Regarding the first modified example of the unmanned mini-submarine 20) A first modified example of the unmanned mini submarine 20 used in the first embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining the first modified example of the unmanned mini submarine 20 used in the first embodiment of the present disclosure. 7, the unmanned mini submersible 20 may use a retrofit camera 32 instead of the forward-facing camera 22. The retrofit camera 32 may be used when it is desired to use a camera with higher performance than the forward-facing camera 22 or when the forward-facing camera 22 breaks down. The retrofit camera 32 is used in place of the forward-facing camera 22 when the forward-facing laser beams 23a and 24a are used, and captures images in the same direction as the forward-facing camera 22, i.e., in the irradiation direction of the forward-facing laser beams 23a and 24a. The retrofit camera 32 is attached to the body 21 of the unmanned mini submarine 20 via an attachment 48. Note that as an example of the retrofit camera 32, a commercially available product such as GoPro (registered trademark) may be used. Also, instead of using the downward camera 30, a retrofit camera (not shown) may be used that is attached for shooting images directly below the aircraft 21. The retrofit camera (not shown) is used instead of the downward camera 30 when the downward laser lights 35a, 36a are used, and captures images in the same direction as the downward camera 30, i.e., the irradiation direction of the downward laser lights 35a, 36a. In this case, too, the retrofit camera (not shown) may be used when a camera with higher performance than the downward camera 30 is desired, or when the downward camera 30 breaks down. As with the retrofit camera 32, a commercially available GoPro (registered trademark) may be used for this retrofit camera (not shown).

[0047] (Second Modification of the Unmanned Mini Submarine 20) A second modified example of the unmanned mini submarine 20 used in the first embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram for explaining the second modified example of the unmanned mini submarine 20 used in the first embodiment of the present disclosure. As shown in FIG. 8, the unmanned small submarine 20 uses a line laser instead of a pointing laser for the laser light emitted by the laser light emitting device 12a. A line laser is a type of laser light in which the shape of the light formed at the irradiation position when the laser energy hits an object is a straight line. As shown in FIG. 8, line lasers 33, 34 emitted from a pair of irradiation ports provided on the body 21 of the unmanned small submersible 20 form a separation distance 34a. When a line laser is used instead of a pointing laser for the forward laser beams 23a, 24a emitted from a pair of forward irradiation ports 23, 24, a separation distance 34a is formed on the ground surface 38 as the separation distance of the irradiation positions instead of separation distance 24c (see Figure 3(a)). When a line laser is used instead of a pointing laser for the downward laser beams 35a, 36a emitted from a pair of downward irradiation ports 35, 36, the separation distance 34a is formed on the ground surface 38 as the separation distance of the irradiation positions instead of the separation distance 36c. In addition, the unmanned small surface boat may also use a line laser as the laser light, similar to the unmanned small submarine boat 20.

[0048] (Regarding the second embodiment of the present disclosure) A measurement system 10 and an unmanned mini submersible 20 according to a second embodiment of the present disclosure will be described with reference to Figures 9 and 10. Figures 9 and 10 are diagrams showing an example of the configuration of the unmanned mini submersible 20 used in the second embodiment of the present disclosure. Note that Figure 10(a) shows the unmanned mini submersible 20 carrying and setting up the quadrat 28, and Figure 10(b) shows the quadrat 28 set up in the seaweed bed 46. The second embodiment differs from the first embodiment in that the length reference is a quadrat 28 and a laser beam is used to set the length reference. Therefore, in the description of the second embodiment, the differences from the first embodiment will be described, and a detailed description of the points in common with the first embodiment will be omitted. In addition, in the unmanned small surface vehicle, as in the unmanned small submarine vehicle 20, the quadrat 28 may be used as a length standard.

[0049] The reference length used by the measurement system 10 and the unmanned mini submersible 20 according to the second embodiment is a quadrat 28 of known size. The quadrant 28 is a square frame with each side measuring 1 meter, but is not limited to this, and is not limited to a specific shape or size, and may be of different shape and size depending on the user's needs. The quadrat 28 is made of polyvinyl chloride tubing with fluorescent vinyl tape wrapped around its outer surface to improve its visibility underwater 45. The quadrat 28 is connected to a rope 50. The rope 50 is connected to the vehicle 1 by being hooked onto a frame portion 51 (see FIG. 9 ) that constitutes part of the vehicle 1, for example, so that the unmanned small submersible 20 can carry the quadrat 28. Note that the number of ropes 50 is not particularly limited, and the quadrat 28 may be carried by one rope 50 or by two or more ropes 50. In addition, the unmanned mini submersible 20 may be equipped with a robot arm (not shown), and the robot arm may be used to grab and carry a part of the quadrat 28. When the quadrat 28 is deployed, the quadrat 28 may be transported to the unmanned mini submersible 20 by a rope 50 to the destination, and when the quadrat 28 is retrieved, the quadrat 28 may be transported to the unmanned mini submersible 20 while being grasped by a robotic arm. The length reference setting unit 60 uses a robot arm to carry the quadrat 28 and set the quadrat 28 on the ground surface 38 within the shooting range of the cameras (forward-facing camera 22, downward-facing camera 30).

[0050] Steps 1 to 5 for measuring the area of ​​the vegetation cover range in which plants cover the ground surface in the seaweed bed 46 using the quadrat 28 will be described below. Step 1 The rope 50 of the quadrat 28 is attached to the unmanned small submarine vehicle 20 or the unmanned small surface vehicle.

[0051] Step 2 The quadrat 28 is transported using a robotic arm (not shown) of the unmanned small submersible 20 or the unmanned small surface boat, and the quadrat 28 is released by operating the robotic arm and placed in the seaweed bed 46 to be photographed.

[0052] Step 3 The attitude of the unmanned small submarine boat 20 or the unmanned small surface boat is controlled to make the body 21 parallel to the ground surface 38, and the downward camera 30 photographs the seaweed bed 46 in the range including the quadrat 28. Alternatively, the attitude of the unmanned small submarine vessel 20 or the unmanned small surface vessel is controlled so that the body 21 is perpendicular to the ground surface 38 and the forward-facing camera 22 photographs the seaweed bed 46 in the area including the quadrat 28.

[0053] Step 4 After the photographing, the robot arm grabs the quadrat 28 or the rope 50, and operates the unmanned small submersible vehicle 20 to recover the quadrat 28 and the unmanned small submersible vehicle 20.

[0054] Step 5 As in the first embodiment, the measurement system 10 is used to determine the coverage and the area of ​​the vegetation coverage range from the captured image 37. The predetermined range in the operations of the vegetation coverage range extraction unit 62, coverage degree calculation unit 63, predetermined range area calculation unit 67, and vegetation coverage range area calculation unit 68 is the entire range within the frame of the quadrat 28.

[0055] (About the measurement method and program) Next, a measurement program according to an embodiment of the present disclosure will be described together with a measurement method with reference to Fig. 11. Fig. 11 is an example of a flowchart of the measurement program according to an embodiment of the present disclosure. The measurement method is executed by the processing unit 10e of the measurement system 10 based on a measurement program. As shown in FIG. 11, the measurement program includes a length reference setting step S60, an image information acquisition step S61, a vegetation coverage range extraction step S62, a coverage degree calculation step S63, a specified range area calculation step S67, and a vegetation coverage range area calculation step S68.

[0056] The measurement program causes the processing unit 10e of the measurement system 10 to realize various functions such as a length reference setting function, an image information acquisition function, a vegetation coverage range extraction function, a coverage degree calculation function, a predetermined range area calculation function, and a vegetation coverage range area calculation function. These functions are executed in the order shown in the flowchart of Fig. 11, but the order can be changed as appropriate. Note that each function overlaps with the description of the various functional units of the measurement system 10 described above, and therefore detailed description thereof will be omitted.

[0057] The length reference setting function is provided on the unmanned small submarine vessel 20 or the unmanned small surface vessel, and sets up a length reference having a known length that is photographed together with the subject of the camera (forward-facing camera 22, downward-facing camera 30) to serve as an indicator of the size of the subject within the shooting range of the camera (forward-facing camera 22, downward-facing camera 30) (S60: length reference setting step).

[0058] The image information acquisition function acquires, as image information, an image 37 of the seaweed bed 46 captured using a camera (forward-facing camera 22, downward-facing camera 30) with the length reference set within the shooting range of the camera (forward-facing camera 22, downward-facing camera 30) (S61: image information acquisition step).

[0059] The vegetation coverage range extraction function extracts the vegetation coverage range within a predetermined range of the captured image 37 from the image information by performing image analysis processing on the image information (S62: vegetation coverage range extraction step).

[0060] The coverage calculation function calculates the ratio of the vegetation coverage range within the predetermined range to the predetermined range as the coverage (S63: coverage calculation step).

[0061] The predetermined range area calculation function calculates the area of ​​the predetermined range based on the length standard included in the photographed image 37 (S67: predetermined range area calculation step).

[0062] The vegetation coverage area calculation function calculates the area of ​​the vegetation coverage within the specified range based on the coverage and the area of ​​the specified range (S68: vegetation coverage area calculation step).

[0063] (Measuring method and measuring program according to other embodiments) A measurement program according to another embodiment will be described together with a measurement method with reference to Fig. 12. Fig. 12 is an example of a flowchart of the measurement program according to another embodiment. The flowchart of the measurement program according to another embodiment shown in FIG. 12 differs from the flowchart of the measurement program shown in FIG. 11 in that an irradiation position detection step S64, a separation distance measurement step S65, and a length reference correction step S66 are added. The measurement method according to the other embodiment is executed by the processing unit 10e of the measurement system 10 based on the measurement program according to the other embodiment shown in FIG. The measurement program for another embodiment shown in Figure 12 includes a length reference setting step S60, an image information acquisition step S61, a vegetation coverage range extraction step S62, a coverage degree calculation step S63, an irradiation position detection step S64, a distance measurement step S65, a length reference correction step S66, a specified range area calculation step S67, and a vegetation coverage range area calculation step S68.

[0064] The measurement program according to another embodiment shown in Fig. 12 causes the processing unit 10e of the measurement system 10 to realize a length reference setting function, an image information acquisition function, a vegetation coverage range extraction function, a coverage degree calculation function, an irradiation position detection function, a distance measurement function, a length reference correction function, a predetermined range area calculation function, and a vegetation coverage range area calculation function, etc. These functions are executed in the order shown in the flowchart of Fig. 12, but the order can be changed as appropriate. Hereinafter, a measurement method and a measurement program according to another embodiment shown in FIG. 12 will be described, focusing only on the differences from the measurement method and the measurement program shown in FIG. Moreover, since each function overlaps with the description of the various functional parts of the measurement system 10 described above, detailed description thereof will be omitted.

[0065] The irradiation position detection function detects the irradiation positions (irradiation positions 23b, 24b, irradiation positions 35b, 36b) of a pair of laser beams (forward laser beams 23a, 24a, downward laser beams 35a, 36a) in the captured image 37 (S64: irradiation position detection step).

[0066] The distance measurement function measures the distance (distance 24c, distance 36c) between the irradiation positions (irradiation positions 23b, 24b, irradiation positions 35b, 36b) of a pair of laser beams (forward laser beams 23a, 24a, downward laser beams 35a, 36a) (S65: distance measurement step).

[0067] The length reference correction function corrects the length reference included in the captured image 37 according to the attitude angle of the cameras (forward camera 22, downward camera 30) at the time of capturing the image.

[0068] According to the above-described embodiment, by shining laser light within the shooting range of the cameras (forward-facing camera 22, downward-facing camera 30), it is possible to set a standard length required for calculating the vegetation cover area, thereby eliminating the complexity compared to a person diving into the sea 45 to set up the quadrats 28.

[0069] Furthermore, according to the above-described embodiment, the quadrat 28 can be installed within the shooting range of the cameras (forward-facing camera 22, downward-facing camera 30) using the unmanned small submarine boat 20 or the unmanned small surface boat, eliminating the hassle of having a person dive into the ocean 45 to install the quadrat 28.

[0070] Furthermore, according to the above-described embodiment, image information of the captured image 37 is subjected to image analysis processing using image segmentation, so that the vegetation coverage area can be accurately extracted from the captured image 37, and ultimately the vegetation coverage area appearing in the captured image 37 can be accurately calculated.

[0071] Furthermore, according to the above-described embodiment, the unmanned small submarine boat 20 and the unmanned small surface boat are equipped with an attitude angle sensor 11b, so that the length reference contained in the captured image 37 can be corrected according to the attitude angle of the cameras (forward-facing camera 22, downward-facing camera 30) at the time of shooting.

[0072] Furthermore, according to the embodiment described above, object detection is performed as an image analysis process on the captured image 37, so that the irradiation positions of the pair of laser beams in the captured image 37 can be detected accurately.

[0073] Furthermore, according to the embodiment described above, since the scale bar 43 can be displayed on the photographed image 37, the magnification (reduction scale) on the photographed image 37 can be accurately known.

[0074] The present disclosure is not limited to the measurement system 10, the measurement method, and the measurement program according to the above-described embodiment, and can be embodied by various other modified examples or application examples without departing from the gist of the present invention described in the claims. In addition, although the term "information" is used in the above-described embodiment, the term "information" can be replaced with "data", and the term "data" can be replaced with "information". [Explanation of symbols]

[0075] 10 Measurement System 10a Communication Interface 10b ROM 10c RAM 10d storage section 10e Processing section 10f Input / Output Interface 11 Input Devices 11a Camera 11b Attitude angle sensor 12 Output Devices 12a Laser light irradiation device 15 Information and Communication Networks 20 Unmanned small submarine (first embodiment) 21 Aircraft 21a (Aircraft) Lengthwise 21b (aircraft) height direction 22 Forward Facing Camera 23 (Pointing laser) Forward-facing irradiation port 23a Forward-facing laser light 23b Irradiation position 23c (forward-facing) aperture distance 24 (Pointing laser) Forward-facing irradiation port 24a Forward-facing laser light 24b Irradiation position 24c Distance (between irradiation positions) 25 Power supply cable 26 Thruster (propeller) 27 Forward-facing light 28 Quadrato 30 Downward Camera 32 Retrofit camera 33 Line laser light 34 Line laser light 34a Separation distance 35 Downward irradiation port 35a Downward laser light 35b Irradiation position 35c Distance between downward-facing irradiation ports 36 Downward irradiation port 36a Downward laser light 36b Irradiation position 36c separation distance 37 Photographed Images 38 Ground surface 39 Seaweed / seaweed 40 Irradiation position 41 Irradiation position 42 Distance (between irradiation positions) 43 Scale bar 45 Undersea 46 Seaweed bed 48 Attachment 49 Forward-facing light 50 Rope 51 Frame section 60 Length standard setting part 61 Image information acquisition unit 62 Vegetation Coverage Extraction Unit 63 Coverage calculation part 64 Irradiation position detection unit 65 Separation distance measurement section 66 Length standard correction section 67 Specified range area calculation unit 68 Vegetation Coverage Area Calculation Section

Claims

1. A measurement system for measuring the area of ​​vegetation coverage in a seaweed bed using an unmanned small submarine or unmanned small surface boat equipped with a camera, comprising: a length reference setting unit provided in the unmanned small submarine or surface watercraft, which sets, within a shooting range of the camera, a length reference having a known length that serves as an index showing a standard for the size of the subject by being photographed together with the subject; an image information acquisition unit that acquires, as image information, an image of the seaweed bed captured by the camera with the length standard set within a shooting range of the camera; a vegetation coverage extraction unit that performs image analysis processing on the image information to extract the vegetation coverage range within a predetermined range of the captured image from the image information; a coverage calculation unit that calculates a ratio of the vegetation coverage area to the specified area as a coverage area; a predetermined range area calculation unit that calculates an area of ​​the predetermined range based on the length criterion included in the captured image; a vegetation coverage area calculation unit that calculates an area of ​​the vegetation coverage area within the specified range based on the coverage and the area of ​​the specified range; A frame portion constituting a part of the body of the unmanned small submarine vehicle or the unmanned small surface vehicle; A rope having one end connected to the frame portion; Equipped with said length standards being quadrats of known size; The quadrat is connected to the other end of the rope, The length reference setting unit sets the quadrat on the ground within the shooting range of the camera. A measurement system comprising:

2. The unmanned small submarine or unmanned small surface vessel is equipped with a robot arm, The length reference installation unit uses the robot arm to carry the quadrat, and operates the robot arm to release the quadrat and install it on the ground within the shooting range of the camera.

2. The measurement system according to claim 1 .

3. The unmanned small submarine or unmanned small surface vessel comprises: An attitude angle sensor for measuring an attitude angle of the unmanned small submarine or surface boat The measurement system of claim 2 further comprising:

4. The measurement system according to claim 1 , wherein the vegetation coverage area extraction unit extracts the vegetation coverage area from the captured image by performing image analysis processing on the image information using image segmentation.

5. A measurement method used in a measurement system for measuring the area of ​​vegetation coverage in a seaweed bed using an unmanned small submarine or unmanned small surface boat equipped with a camera, comprising the steps of: The measurement system comprises: a length reference setting step of setting, within a shooting range of the camera, a length reference having a known length that is provided on the unmanned small submarine or unmanned small surface boat and serves as an index showing a standard for the size of the subject by being photographed together with the subject of the camera; an image information acquisition step of acquiring, as image information, an image of the seaweed bed captured by the camera with the length standard set within a range of the camera; a vegetation coverage extraction step of extracting the vegetation coverage range within a predetermined range of the photographed image from the image information by performing image analysis processing on the image information; a coverage calculation step of calculating a ratio of the vegetation coverage area to the predetermined area as a coverage area; a predetermined range area calculation step of calculating an area of ​​the predetermined range based on the length criterion included in the photographed image; a vegetation coverage area calculation step of calculating an area of ​​the vegetation coverage area within the predetermined range based on the coverage and the area of ​​the predetermined range; Run A frame portion constituting a part of the body of the unmanned small submarine vehicle or the unmanned small surface vehicle; A rope having one end connected to the frame portion; Equipped with said length standards being quadrats of known size; The quadrat is connected to the other end of the rope, The length reference setting step includes setting the quadrat on the ground surface within the photographing range of the camera. A measuring method comprising:

6. A measurement program used in a measurement system for measuring an area of ​​vegetation coverage in a seaweed bed using an unmanned small submarine or unmanned small surface boat equipped with a camera, comprising: The measurement system includes: a length reference setting function provided in the unmanned small submarine or surface watercraft, which sets, within a shooting range of the camera, a length reference having a known length that serves as an index showing a standard for the size of the subject by being photographed together with the subject; an image information acquisition function that acquires, as image information, an image of the seaweed bed captured by the camera with the length standard set within the range of the camera; a vegetation coverage extraction function that performs image analysis processing on the image information to extract the vegetation coverage range within a predetermined range of the captured image from the image information; a coverage calculation function for calculating a ratio of the vegetation coverage area to the specified area as a coverage area; a predetermined range area calculation function that calculates an area of ​​the predetermined range based on the length criterion included in the photographed image; a vegetation coverage area calculation function that calculates the area of ​​the vegetation coverage area within the specified range based on the coverage and the area of ​​the specified range; Realize this, A frame portion constituting a part of the body of the unmanned small submarine vehicle or the unmanned small surface vehicle; A rope having one end connected to the frame portion; Equipped with said length standards being quadrats of known size; The quadrat is connected to the other end of the rope, The length reference setting function sets the quadrat on the ground within the range of the camera. A measurement program comprising:

Images