Flood detection method and flood detection system

Abstract

To provide a flood detection system that can accurately grasp flood situations.SOLUTION: A flood detection system 1 includes: a photographing unit 11 that photographs a detection target surface 50; an irradiation unit 12 that radiates millimeter waves toward the detection target surface 50; a receiving unit 13 that receives reflected millimeter waves reflected from the detection target surface 50; and a flood detection unit 21 that detects a flooded range A2 based on the intensity of the reflected waves. The irradiation unit 12 is capable of radiating millimeter waves so as to spread in a fan shape in a vertical direction with respect to a millimeter wave irradiation center axis L1, and the millimeter waves are radiated from the irradiation unit 12 so that the irradiation center axis L1 is inclined with respect to the detection target surface 50.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a water immersion detection method and a water immersion detection system for detecting a water immersion range on a detection target surface.

Background Art

[0002] As a water immersion detection system for detecting ground water immersion such as road water immersion caused by rainwater or construction site water immersion caused by spring water, there is a system that irradiates microwaves perpendicularly to the detection target surface and detects moisture on the detection target surface based on the intensity of the reflected wave (for example, refer to Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-described conventional water immersion detection system detects a change in moisture at one point on the detection target surface, and cannot detect moisture on the detection target surface linearly and planarly. Accordingly, the conventional water immersion detection system cannot determine the boundary between the water immersion range and the non-water immersion range on the detection target surface, which poses a problem that it is difficult to grasp the water immersion situation. The present invention aims to solve the above-described problems and provide a water immersion detection method and a water immersion detection system capable of accurately grasping the water immersion situation on a detection target surface.

Means for Solving the Problems

[0005] To solve the aforementioned problems, the present invention provides a flood detection method comprising: irradiating a surface to be detected from an irradiation unit of a flood detection system with millimeter waves so that the irradiation center axis of the millimeter waves is inclined with respect to the surface to be detected and the millimeter waves spread out in a fan shape relative to the irradiation center axis; detecting the flooded area using a flood detection unit of the flood detection system based on the intensity of the reflected millimeter waves received by the receiving unit of the flood detection system; and displaying an image of the surface to be detected on the image display unit of the flood detection system, and displaying the flooded area and the non-flooded area in the image of the surface to be detected using varying shades of gray. The intensity of the reflected wave that marks the boundary between a flooded state and a non-flooded state is set as a threshold, and the threshold is set for each type of surface to be detected. The flood detection unit determines that a surface is flooded when the intensity of the reflected wave is less than or equal to the threshold. To solve the aforementioned problems, the present invention provides a flood detection system comprising: an imaging unit for imaging a surface to be detected; an irradiation unit for irradiating millimeter waves toward the surface to be detected; a receiving unit for receiving reflected millimeter waves reflected from the surface to be detected; a flood detection unit for detecting the flooded area based on the intensity of the reflected waves; a data creation unit for creating flood image data by superimposing the flooded area onto an image of the surface to be detected captured by the imaging unit; and an image display unit for displaying the flood image data on a screen. The irradiation unit is capable of irradiating millimeter waves so as to spread in a fan shape vertically from the irradiation center axis of the millimeter waves, and the irradiation unit is capable of irradiating millimeter waves such that the irradiation center axis is inclined with respect to the surface to be detected. The intensity of the reflected wave that marks the boundary between a flooded state and a non-flooded state is set as a threshold, and the threshold is set for each type of surface to be detected. The flood detection unit determines that a flooded state exists when the intensity of the reflected wave is less than or equal to the threshold. The image display unit displays the image of the surface to be detected, dividing the flooded area and the non-flooded area with varying shades of gray. In the flood detection method and flood detection system of the present invention, millimeter waves are irradiated toward the surface to be detected, and flooding is detected based on the intensity of the reflected waves. Millimeter waves are electromagnetic waves with short wavelengths of 1 mm to 10 mm and can transmit a very large amount of information. In addition, when millimeter waves are irradiated at an angle to the water surface, the intensity of the reflected waves decreases significantly. A flood detection method and flood detection system using millimeter waves with such characteristics can accurately detect whether or not the surface to be detected is flooded. Furthermore, in the flood detection method and flood detection system of the present invention, millimeter waves can be irradiated so as to spread in a fan shape vertically with respect to the central irradiation axis of the millimeter waves, and the central irradiation axis of the millimeter waves is inclined with respect to the detection target surface. In this way, millimeter waves are irradiated linearly onto the detection target surface. As a result, the flood detection method and flood detection system of the present invention can detect the presence or absence of flooding in a linear area on the detection target surface, and thus the boundary between the flooded area and the non-flooded area on the detection target surface can be determined. Furthermore, the millimeter waves may be irradiated from the irradiation unit in a fan-shaped manner, spreading vertically and horizontally from the irradiation center axis. In this way, when millimeter waves are diffused three-dimensionally from the irradiation unit and irradiated, it is possible to detect the presence or absence of water ingress in a planar area on the target surface, thereby enabling the spatial determination of the boundary between the inundated area and the non-inundated area on the target surface.

[0006] In the flood detection method described above, an image of the surface to be detected is displayed on the image display unit of the flood detection system, and the flooded area and the non-flooded area are demarcated and displayed on the image of the surface to be detected using varying shades of gray, thereby allowing the boundary between the flooded area and the non-flooded area on the surface to be detected to be grasped visually. The aforementioned flood detection system teeth The system includes a data creation unit that creates flood image data by superimposing the flooded area onto the image of the detection target surface captured by the imaging unit. Therefore This allows for the visualization of the boundary between flooded and non-flooded areas on the detection target surface. Furthermore, the aforementioned flood detection system teeth It includes an image display unit that displays the aforementioned flood image data on a screen. Therefore Furthermore, by displaying the flooded and non-flooded areas in the image of the surface to be detected using varying shades of gray, it becomes easier to understand the flooding status of the surface to be detected.

[0007] before The flood detection unit determines that a flooded state exists when the intensity of the reflected wave is below a threshold. ru. In this configuration, the intensity of the reflected wave that marks the boundary between flooded and non-flooded areas on the target surface is set as a threshold according to the type of target surface and the surrounding environment, thereby enabling accurate detection of the boundary between flooded and non-flooded areas on various target surfaces.

[0008] Furthermore, the flood detection system of the present invention can also be used to detect the depth of flooding at each point on the surface to be detected. For example, if the surface to be detected is a slope with a constant gradient, and the elevation difference at each point on the surface to be detected can be determined, the flood detection system of the present invention can be used to detect the boundary between the flooded area and the non-flooded area, and the depth of flooding at each point on the surface to be detected can be calculated based on the elevation difference at each point relative to the boundary position. [Effects of the Invention]

[0009] The flood detection method and flood detection system of the present invention use millimeter waves to detect the presence or absence of flooding in a predetermined range on the surface to be detected. Since the boundary between the flooded area and the non-flooded area on the surface to be detected can be detected with high accuracy, the flooding status of the surface to be detected can be accurately grasped. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view showing a flood detection system used in a flood detection method according to an embodiment of the present invention. [Figure 2] This is a perspective view showing an experimental example of a flood detection system according to an embodiment of the present invention. [Figure 3] This is a diagram showing the configuration of an experimental example of a flood detection system according to an embodiment of the present invention. [Figure 4] This figure shows an experimental example of flood detection using a flood detection system according to an embodiment of the present invention, and is an image of the entire surface to be detected when it is not flooded. [Figure 5] This figure shows an experimental example of flood detection using a flood detection system according to an embodiment of the present invention, and is an image of a case where a part of the surface to be detected is flooded. [Figure 6]This is a conceptual diagram showing a configuration for calculating the flood depth at each point on a detection target surface using the flood detection system according to an embodiment of the present invention. [Mode for Carrying Out the Invention]

[0011] Embodiments of the present invention will be described in detail with appropriate reference to the drawings. Figure 1 is a side view showing the flood detection system used in the flood detection method according to the embodiment of the present invention. In the flood detection method of the present embodiment, as shown in Figure 1, the flood status of the detection target surface 50 with potential flood risk, such as inside a tunnel under construction where flooding due to spring water is a concern, an unpaved temporary road with poor drainage, or a riverbed, is detected. On the detection target surface 50 shown in Figure 1, a flooded area A2 is formed on the surface by spring water from the ground. In the flood detection method of the present embodiment, first, millimeter waves are emitted from the irradiation unit 12 of the flood detection system 1 to the detection target surface 50 so as to spread three-dimensionally in a fan shape, such that the central axis of millimeter wave irradiation is inclined with respect to the detection target surface. Subsequently, the flood detection unit 21 (see Figure 3) of the flood detection system 1 detects the flooded area A2 based on the intensity of the reflected millimeter wave received by the receiving unit 13 (see Figure 3) of the flood detection system 1. Furthermore, the image of the detection target surface 50 is displayed on the screen 25 (see Figure 3) of the image display unit 23 (see Figure 3) of the flood detection system 1, and the flooded area A2 and the non-flooded area A1 are displayed on the image of the detection target surface 50 partitioned by grayscale levels.

[0012] Figure 2 is a perspective view showing an experimental example of the flood detection system according to the embodiment of the present invention. Next, the configuration of the flood detection system 1 of the present embodiment will be described based on the experimental example of the flood detection system 1 shown in Figure 2. As shown in Figure 2, the experimental example of the water immersion detection system 1 of the present embodiment is for detecting the water immersion state of the detection target surface 50 produced for testing. The test detection target surface 50 is a rectangular region extending in the front-rear direction. The front part of the detection target surface 50 is formed horizontally, and the rear part is inclined so as to descend toward the rear. In addition, the test detection target surface 50 is covered with gravel. That is, irregularities are formed on the test detection target surface 50. On the detection target surface 50 shown in Figure 2, a water immersion range A2 is provided at the rear part, and the front part is a dry non-water immersion range A1.

[0013] Figure 3 is a configuration diagram of an experimental example of the water immersion detection system according to the embodiment of the present invention. As shown in Figure 3, the water immersion detection system 1 includes a radar device 10 that photographs the detection target surface 50 and performs transmission and reception of millimeter waves, and a terminal device 20 that creates water immersion image data and displays the water immersion image data on the screen 25.

[0014] The radar device 10 includes an imaging unit 11, an irradiation unit 12 that irradiates millimeter waves, and a receiving unit 13 that receives reflected waves of millimeter waves. As shown in Figure 2, the radar device 10 is attached to the upper end of a support column 15 erected at the front end of the detection target surface 50. As shown in Figure 3, the imaging unit 11 is a camera that photographs the detection target surface 50 from above, and the image data of the detection target surface 50 is output to the terminal device 20. The irradiation unit 12 irradiates the detection target surface 50 with millimeter waves. Millimeter waves are electromagnetic waves with a wavelength of 1 mm to 10 mm and a frequency of 30 GHz to 300 GHz. When a millimeter wave is irradiated in a state inclined with respect to the water surface, the intensity of its reflected wave is greatly reduced. The irradiation unit 12 irradiates the detection target surface 50 with millimeter waves. The orientation of the irradiation unit 12 is set such that the irradiation central axis L1 of the millimeter wave is inclined with respect to the detection target surface 50. Furthermore, as shown in Figure 2, the irradiation unit 12 irradiates millimeter waves in a fan shape in the vertical (up and down) and horizontal (left and right) directions relative to the irradiation central axis L1. In other words, the millimeter waves irradiated from the irradiation unit 12 are diffused radially in the vertical and horizontal directions, spreading three-dimensionally and irradiating the detection target surface 50 in a planar manner. The receiving unit 13 shown in Figure 3 receives millimeter-wave reflected waves from the detection target surface 50. The intensity of the reflected waves received by the receiving unit 13 is output to the terminal device 20.

[0015] In the flood detection system 1 of this embodiment, as shown in Figure 2, the radar device 10 is installed at a height of 2 m above the detection target surface 50. The irradiation center axis L1 of the millimeter waves emitted from the irradiation unit 12 of the radar device 10 is set to be inclined at an angle of 30 degrees with respect to the detection target surface 50. Furthermore, the millimeter waves emitted from the irradiation unit 12 are set to spread out in a fan shape at an angle of 10 degrees vertically (up and down) with respect to the irradiation center axis L1, and also spread out in a fan shape at an angle of approximately 15 degrees horizontally (left and right) with respect to the irradiation center axis L1. As a result, the millimeter waves emitted from the irradiation unit 12 are irradiated in a planar manner onto the detection target surface 50.

[0016] As shown in Figure 3, the terminal device 20 is a computer equipped with a CPU, RAM, ROM, display, etc., and the CPU executes programs stored in ROM, etc., to perform the tasks of each component. The terminal device 20 includes a flood detection unit 21 for detecting the extent of flooding, a data creation unit 22 for creating flood image data, and an image display unit 23 for displaying the flood image data on a screen 25. The flood detection unit 21 detects the flooded area A2 based on the intensity of the reflected waves. If the intensity of the reflected waves is below a threshold, the flood detection unit 21 determines that the millimeter waves are being reflected from the water surface and identifies the reflection region where the intensity of the reflected waves is below the threshold as the flooded area A2. If the intensity of the reflected waves is greater than the threshold, the flood detection unit 21 determines that the millimeter waves are being reflected from a non-flooded surface (dry surface) and identifies the reflection region where the intensity of the reflected waves is greater than the threshold as the non-flooded area A1. The threshold value used to determine whether or not water is present is a value set in advance through experiments and is stored in the terminal device 20. This threshold value is set according to the type of surface to be detected 50 and the surrounding environment. The data creation unit 22 creates flood image data by overlaying the flooded area A2 and the non-flooded area A1 onto the image of the detection target surface 50 captured by the imaging unit 11. The image display unit 23 displays an image on the screen 25 that shows the flooded area A2 and the non-flooded area A1 separated by varying shades on the image of the detection target surface 50, based on the flooded image data. In this embodiment, the non-submerged area A1, where the intensity of the reflected wave is greater than the threshold, is displayed in a dark color, and the submerged area A2, where the intensity of the reflected wave is less than or equal to the threshold, is displayed in a colorless color (see Figure 5).

[0017] Next, we will describe the procedure for detecting the flooding status of the test target surface 50 using the flooding detection system 1 of this embodiment as an experimental example. In the radar device 10 shown in Figure 3, the imaging unit 11 captures the detection target surface 50 and outputs the image data to the terminal device 20. Furthermore, the radar device 10 emits millimeter waves from its irradiation unit 12 onto the detection target surface 50, and the reflected millimeter waves from the detection target surface 50 are received by the receiving unit 13. The receiving unit 13 outputs the intensity of the reflected waves to the terminal device 20. The flood detection unit 21 of the terminal device 20 detects the flooded area where the intensity of the reflected wave is below a threshold, and outputs data for the flooded area A2 and the non-flooded area A1 to the data creation unit 22. The data creation unit 22 creates flooded image data by overlaying the flooded area A2 and the non-flooded area A1 onto the image data of the detection target surface 50 captured by the shooting unit 11, and outputs this flooded image data to the image display unit 23. The image display unit 23 displays an image on screen 25 that shows the flooded area A2 and the non-flooded area A1 separated by varying shades on the image of the detection target surface 50, based on the flooded image data.

[0018] Figure 4 shows a diagram illustrating flood detection by a flood detection system according to an embodiment of the present invention, and is an image of the case where the entire surface to be detected is not flooded. Figure 5 shows a diagram illustrating flood detection by a flood detection system according to an embodiment of the present invention, and is an image of the case where a part of the surface to be detected is flooded. As shown in Figure 4, if the entire detection target surface 50 is in a non-water-immersed area A1 (dry state), the non-water-immersed area A1 is superimposed in a darker color over the entire detection target surface 50. As shown in Figure 5, when a flooded area A2 is formed at the rear of the detection target surface 50, the flooded area A2 is superimposed in a colorless manner at the rear of the detection target surface 50 (upper part of screen 25), and the non-flooded area A1 is superimposed in a dark color at the front of the detection target surface 50 (lower part of screen 25).

[0019] In the flood detection system 1 and flood detection method described above, millimeter waves are irradiated onto the detection target surface 50, as shown in Figure 2. Millimeter waves can transmit a very large amount of information, and when irradiated at an angle to the water surface, the intensity of the reflected waves decreases significantly. Therefore, the flood detection system 1 and flood detection method of this embodiment can accurately detect whether or not the detection target surface 50 is flooded. In the flood detection system 1 and flood detection method of this embodiment, millimeter waves are irradiated in a fan shape that spreads vertically and horizontally, and the central axis L1 of the millimeter wave irradiation is inclined with respect to the detection target surface 50. As a result, the flood detection system 1 and flood detection method of this embodiment can detect the presence or absence of flooding on the target surface 50 in a surface manner, as shown in Figure 5, and can therefore determine the boundary between the flooded area A2 and the non-flooded area A1 on the target surface 50 in a surface manner. In the flood detection system 1 and flood detection method of this embodiment, the flooded area A2 is determined when the intensity of the reflected wave is below a threshold. With this configuration, the boundary between flooded and non-flooded areas on the detection target surface 50 can be set to a threshold value depending on the type of detection target surface 50 and the surrounding environment, thereby enabling accurate detection of the boundary between flooded area A2 and non-flooded area A1 on various detection target surfaces 50. In the flood detection system 1 and flood detection method of this embodiment, the flooded area A2 and the non-flooded area A1 are demarcated in varying shades on the image of the surface to be detected 50 and displayed on the screen 25, making it easy to understand the flooding status of the surface to be detected 50.

[0020] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from its spirit. In the flood detection system 1 of this embodiment, the millimeter waves emitted from the irradiation unit 12 shown in Figure 2 are configured to spread in a fan shape in both the vertical and horizontal directions. However, the millimeter waves emitted from the irradiation unit 12 may be configured to spread in a fan shape only in the vertical direction. In this configuration, since the millimeter waves are emitted over a linear area on the detection target surface 50, the boundary between the flooded area A2 and the non-flooded area A1 within a linear area on the detection target surface 50 can be detected. Furthermore, in the flood detection system 1, the installation height of the irradiation unit 12, the inclination angle of the millimeter wave irradiation center axis L1 with respect to the detection target surface 50, and the angle at which the millimeter waves spread in a fan shape are not limited, but are set appropriately according to the condition of the detection target surface 50 and the surrounding environment.

[0021] Furthermore, in the flood detection system 1, if the detection target surface 50 is a slope with a constant gradient, or if the elevation difference at each point on the detection target surface 50 can be determined, then, as shown in Figure 6, the boundary between the flooded area A2 and the non-flooded area A1 can be detected, and the flood depth at each point on the detection target surface 50 can be calculated based on the elevation difference at each point on the detection target surface 50 relative to that boundary position. The system can also detect the depth of flooding at each point on the target surface. For example, the flood detection system of the present invention can detect the boundary between the flooded area and the non-flooded area, and calculate the depth of flooding at each point on the target surface based on the elevation difference of each point relative to the boundary location. [Explanation of Symbols]

[0022] 1. Flood detection system 10. Radar equipment 11. Photography Department 12 Irradiation area 13 Receiving Unit 15 Posts 20 Terminal devices 21 Flood detection unit 22 Data Creation Section 23 Image display section 25 screens 50 detection target surfaces A1 Non-flooded area A2 Flooded area L1 Irradiation center axis

Claims

1. The process involves irradiating the surface to be detected from the irradiation unit of the flood detection system with millimeter waves, such that the irradiation center axis of the millimeter waves is inclined with respect to the surface to be detected, and the millimeter waves spread out in a fan shape relative to the irradiation center axis; The steps include: detecting the flooded area based on the intensity of the millimeter-wave reflected waves received by the receiving unit of the flood detection system, The system includes the step of displaying an image of the surface to be detected on the image display unit of the flood detection system, and displaying the flooded area and the non-flooded area on the image of the surface to be detected using varying shades of gray, The intensity of the reflected wave that marks the boundary between the flooded state and the non-flooded state is set as a threshold, and the threshold is set for each type of surface to be detected. The flood detection method is characterized in that the flood detection unit determines that a flooded state exists when the intensity of the reflected wave is below the threshold.

2. A camera unit that photographs the surface to be detected, An irradiation unit that irradiates millimeter waves toward the detection target surface, A receiving unit that receives the reflected millimeter wave reflected from the detection target surface, A flood detection unit that detects the flooded area based on the intensity of the reflected wave, A data creation unit creates flood image data by superimposing the flooded area onto the image of the detection target surface captured by the aforementioned imaging unit, The system includes an image display unit that displays the aforementioned flood image data on a screen, The irradiation unit is capable of irradiating millimeter waves so as to spread out in a fan shape vertically from the central axis of the millimeter wave irradiation, The millimeter waves are irradiated from the irradiation unit such that the irradiation center axis is inclined with respect to the detection target surface. The intensity of the reflected wave that marks the boundary between a flooded state and a non-flooded state is set as a threshold, and the threshold is set for each type of surface to be detected. The flood detection unit determines that a flooded state exists when the intensity of the reflected wave is less than or equal to the threshold. The flood detection system is characterized in that the image display unit displays the flooded area and the non-flooded area in an image of the surface to be detected using varying shades of gray.

3. The flood detection system according to claim 2, characterized in that the irradiation unit is capable of irradiating millimeter waves so as to spread out in a fan shape in the vertical and horizontal directions from the irradiation center axis.

Images