Snow dropping damage determination method

Abstract

To provide a snow dropping damage determination method for determining whether or not damage of a structure under power transmission lines is caused by snow dropping from power transmission equipment.SOLUTION: A snow dropping damage determination method 20 for determining the existence of damage caused by snow dropping from power transmission equipment of a structure existing on the ground includes: a pre-snowfall data acquisition process of a step S21 of photographing the structure before snowfall; a pre-snowfall detection process of a step S22 of detecting pre-snowfall damage of the structure; a during-snowfall data acquisition process of a step S23 of acquiring a during-snowfall image data in the range; a snow dropping range identification process of a step S24 of identifying a snow dropping range snow dropping occurs on the structure; post-snow melting data acquisition process of a step S25 of photographing the structure after snow melting; a post-snow melting detection process of a step S26 of detecting post-snow melting damage of the structure; and a damage determination step of a step S27 of determining the existence of damage caused by snow dropping.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for determining whether or not a structure has been damaged by falling snow, and more particularly to a method for determining whether or not a structure has been damaged by falling snow from power transmission equipment. [Background technology]

[0002] Traditionally, snow and ice that has adhered to power transmission equipment such as power lines and towers has fallen and damaged structures on the ground, such as greenhouses. In such cases, the power transmission and distribution company has compensated the owners of the structures. However, in reality, after the snow melts, it is difficult to determine whether the damage was caused by snow falling from the transmission equipment or by other factors. As a result, transmission and distribution companies are unable to accurately determine the need for compensation and the extent of such compensation, and they have difficulty determining the details of compensation when negotiating with owners. The amount of ice and snow adhering to power lines can be used to estimate the possibility of snow falling from power transmission equipment. Therefore, in recent years, a technology has been developed that can measure the amount of ice and snow that has accumulated on power transmission lines, although this is not for the purpose of compensation negotiations, and an invention related to this has already been disclosed.

[0003] Patent document 1, titled "System for measuring the amount of ice and snow accretion on overhead power lines and method for measuring the amount of ice and snow accretion on overhead power lines," discloses an invention relating to a system for measuring the amount of ice and snow accretion that can quickly measure the amount of ice and snow accretion on overhead power lines. The invention disclosed in Patent Document 1 is a system for measuring the amount of ice and snow that has accumulated on an overhead power line, and is characterized in that it comprises an aircraft equipped with a photographing device and a measuring device that measures the amount of ice and snow that has accumulated on the overhead power line, the aircraft photographing the overhead power line with the photographing device while flying and transmitting the image data to the measuring device, the measuring device calculating the sag of the overhead power line based on the transmitted image data, and measuring the amount of ice and snow that has accumulated on the overhead power line based on the calculated sag of the overhead power line. In an invention having such characteristics, in an emergency, for example, in the event of a short circuit caused by snow or ice adhering to an overhead power line, it is possible to quickly measure the amount of ice and snow that has accumulated on the overhead power line and quickly grasp the situation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-161060 Summary of the Invention [Problem to be solved by the invention]

[0005] The invention disclosed in Patent Document 1 is certainly effective in that it can measure the amount of ice and snow that has adhered to a power transmission line in an emergency. However, since the amount of ice and snow that has adhered to the overhead power transmission line is calculated based on the sag of the overhead power transmission line, it is necessary to calculate the difference in elevation between the support point of the power transmission line, which is supported by a pair of transmission towers, and the aircraft, which makes the process complicated. Furthermore, the invention disclosed in Patent Document 1 is primarily concerned with the rapid measurement of the amount of snow and ice that has accumulated, and so although it is possible to estimate the possibility of falling snow being one of the causes of damage to structures below power lines, it does not consider whether falling snow actually has an effect on the structures.

[0006] The present invention has been made in response to the above-mentioned conventional circumstances, and aims to provide a method for determining snow damage caused by falling snow, which determines whether damage to structures under power lines is caused by snow falling from power transmission equipment. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the first invention is a snow fall damage determination method for determining whether or not a structure on the ground has damage caused by snow falling from power transmission equipment, characterized in that it includes a pre-snow fall data acquisition process in which a photographing means mounted on an aircraft photographs an area on the ground including the structure before snow falls and acquires pre-snow fall image data of the area, a pre-snow fall detection process in which a damage detection unit detects pre-snow fall damage to the structure from the pre-snow fall image data, a snow fall data acquisition process in which the photographing means photographs the area when snow falls and acquires snow fall image data of the area, a snow fall range identification process in which a snow fall range detection unit identifies the snow fall range where snow has fallen on the structure from the snow fall image data, a post-snow melt data acquisition process in which the photographing means photographs the area after the snow melts and acquires post-snow melt image data of the area, a post-snow melt detection process in which the damage detection unit detects post-snow melt damage to the structure from the post-snow melt image data, and a damage determination process in which a determination unit determines whether or not there is damage based on the pre-snow fall damage, the post-snow melt damage, and the snow fall range.

[0008] In the invention having such a configuration, the structure is assumed to be a structure whose roof is made of a relatively easily damaged material, such as an agricultural greenhouse or a warehouse, and the flying object is, for example, a drone or a helicopter. Furthermore, both the pre-snowfall image data and post-snowmelt image data acquired by the photographing means are transmitted to the damage detection unit by the wireless communication means. In this application, falling snow refers to at least one of snow and ice.

[0009] In the invention having the above configuration, the pre-snow accumulation image data and the post-snow melt image data each include the same structure. The damage detection unit detects damage to the same structure in the pre-snow accumulation image data and the post-snow melt image data. Note that this damage is, for example, a hole or a scratch on the roof of the structure. However, this damage is thought to be caused not only by snow falling from the power transmission equipment, but also by factors such as the weight of accumulated snow and deterioration of the structure itself over time.

[0010] Therefore, the snow falling range detection unit identifies the snow falling range where snow is falling on the structure from the image data at the time of snow accumulation, and the judgment unit further judges whether or not there is damage, for example, based on whether or not the damage that has increased after the snow melts is included in the snow falling range.

[0011] The second invention is characterized in that, in the first invention, the damage assessment process includes a difference area identification process and a first assessment process, and in the difference area identification process, the assessment unit compares the damage before snow accumulation with the damage after snow melting and identifies the difference areas between the damage before snow accumulation and the damage after snow melting, and in the first assessment process, the assessment unit determines that the structure has damage caused by falling snow if the difference areas are included in the range of falling snow, and outputs the first assessment result.

[0012] In an invention having such a configuration, in addition to the function of the first invention, in the difference area identification process, the judgment unit, for example, subtracts the damage before snow accumulation from the damage after snow melting, thereby identifying the difference area between the location of the damage before snow accumulation and the location of the damage after snow melting.

[0013] Then, in the first determination step, the determination unit determines that the structure has damage caused by falling snow only when the identified different location is included in the falling snow range. In contrast, if the identified difference area is within the area occupied by the structure where snow has accumulated but is not included in the area where snow has fallen, the judgment unit determines that the increased damage at the difference area does not correspond to damage caused by snow falling from the power transmission equipment.

[0014] The third invention is characterized in that, in the first or second invention, the structure is a greenhouse, the aircraft is equipped with a temperature detection means in addition to the photographing means, the pre-snow accumulation data acquisition process, in addition to acquiring pre-snow accumulation image data, the temperature detection means detects the temperature of the area to acquire pre-snow accumulation temperature data, the post-snow melt data acquisition process, in addition to acquiring post-snow melt image data, the temperature detection means detects the temperature of the area to acquire post-snow melt temperature data, the pre-snow accumulation detection process, in addition to acquiring pre-snow accumulation image data, the damage detection unit detects holes and discolored areas that have occurred in the structure from the pre-snow accumulation image data and detects areas of temperature change that have occurred in the structure from the pre-snow accumulation temperature data, and the post-snow melt detection process, in addition to acquiring pre-snow accumulation image data, the damage detection unit detects holes and discolored areas from the post-snow melt image data and detects areas of temperature change from the post-snow melt temperature data.

[0015] In the invention having such a configuration, for example, an infrared sensor is used as the temperature detection means. The temperature data before snow accumulation and the temperature data after snow melting acquired by the temperature detection means are both transmitted to the damage detection unit by wireless communication means.

[0016] In the invention having the above configuration, in addition to the effects of the first or second invention, if damage to a structure causes warm air inside the structure to leak out through the damage, a temperature difference occurs between the damage and its surroundings, and the temperature detection means detects this temperature difference, thereby detecting the location of the temperature change.

[0017] In addition, in the pre-snowfall detection process and the post-snowmelt detection process, the damage detection unit detects at least one of holes, discolored areas, and temperature change areas that have occurred in the structure, thereby improving the sensitivity of damage detection compared to when only holes and discolored areas are detected.

[0018] The fourth invention is characterized in that, in the second invention, a snow accumulation amount calculation step is provided immediately before or immediately after the snow falling range identification step, and a second judgment step is provided after the first judgment step, and in the snow accumulation amount calculation step, a snow accumulation amount calculation unit calculates the amount of snow adhering to the power transmission lines that constitute the power transmission equipment from image data at the time of snow accumulation, and in the second judgment step, the judgment unit determines that there is damage to the structure due to falling snow if the amount of snow accumulation exceeds a predetermined snow accumulation amount threshold, and outputs a second judgment result.

[0019] In an invention having such a configuration, in addition to the effects of the second invention, in the snow accumulation amount calculation process, the snow accumulation amount calculation unit extracts, for example, the diameter of snow adhering to a power line from the snow accumulation image data, and then compares the diameter of the snow with the known diameter of the power line to calculate the amount of snow adhering to the power line.

[0020] In the second determination step, if the calculated snow accumulation amount exceeds a preset snow accumulation amount threshold, the determination unit determines that the structure has been damaged by falling snow. This is because unless there is a certain amount of snow accumulation, it is considered unlikely that falling snow will generate enough force to damage the structure. [Effects of the Invention]

[0021] According to the first invention, pre-snow accumulation damage and post-snow melt damage are detected from pre-snow accumulation image data and post-snow melt image data, respectively, captured by an imaging means mounted on an aircraft of an area on the ground that includes a structure, so that each location of pre-snow accumulation damage and post-snow melt damage can be accurately detected. In addition, the determination unit determines whether or not there is damage, for example, based on whether the damage that has increased after the snow melts is included in the range of falling snow, so it is possible to distinguish between damage caused by snow falling from the power transmission equipment and damage caused by other factors.

[0022] According to the second invention, in addition to the effects of the first invention, the determination unit determines that the structure has damage caused by falling snow only if the identified difference is included in the range of falling snow, so it is possible to specifically indicate the location of damage caused by falling snow. This allows the electricity transmission and distribution company to accurately understand the need for compensation and its level, and to appropriately determine the content of compensation when negotiating with the owner.

[0023] According to the third invention, in addition to the effects of the first or second invention, the temperature change points can be detected by capturing the temperature difference between the damage and its surroundings, making it possible to detect, for example, dirt adhering to the roof of a structure or damage that could not be detected due to reflected light in image data before snowfall or image data during snowfall.

[0024] According to the fourth invention, in addition to the effect of the second invention, the presence or absence of damage caused by falling snow is determined in two stages, namely, the first determination process and the second determination process, thereby improving the reliability of the determination result output by the determination unit compared to when only the first determination process is executed. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a diagram illustrating the configuration of a falling snow damage determination system that executes a falling snow damage determination method according to an embodiment. [Figure 2] FIG. 1 is a process diagram of a method for determining damage caused by falling snow according to an embodiment. [Figure 3] This is a pre-snow image showing pre-snow damage to the structure. [Figure 4] This is an image of snowfall in which the snow-covered area is identified. [Figure 5] This is an image of snow accumulation with the area of ​​falling snow identified. [Figure 6] This is a post-snowmelt image showing damage to the structure. [Figure 7] This is an image after snow melting, showing the differences between damage before snow accumulation and damage after snow melting. [Figure 8] This is the first judgment result. [Figure 9] A process diagram of a method for determining snow damage in a modified example of the embodiment. [Figure 10] This is an enlarged image of a power line included in an image of snowfall. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0026] First, the configuration of the falling snow damage determination system will be described with reference to Fig. 1. Fig. 1 is a configuration diagram of the falling snow damage determination system that executes the falling snow damage determination method according to the embodiment. As shown in FIG. 1, the falling snow damage determination system 1 includes a falling snow damage determination device 2 and an aircraft 16. Specifically, the falling snow damage determination device 2 is a computer, and the flying object 16 is a drone remotely controlled by the falling snow damage determination device 2 via a wireless communication channel 17.

[0027] The falling snow damage determination device 2 also includes a communication unit 3, an output unit 4, a control unit 5, and a memory unit 10. Of these, the communication unit 3 receives various data transmitted from the flying object 16, and also outputs commands to control flight and photography, such as the flight route of the flying object 16 and the timing of image capture.

[0028] The output unit 4 outputs the first determination result and the second determination result obtained by the determination unit 8, which will be described later. Specifically, the output unit 4 is a display screen.

[0029] The control unit 5 is a central control device that controls all operations of the falling snow damage determination device 2 and the flying body 16, and is equipped with a damage detection unit 6, a falling snow range detection unit 7, a determination unit 8, and a snow accumulation amount calculation unit 9.

[0030] The memory unit 10 is a storage medium that stores various data sent and received via the communication unit 3, the first judgment results, etc., and is equipped with an input data memory unit 11, a damage memory unit 12, a snow falling range memory unit 13, a judgment result memory unit 14, and a snow accumulation amount memory unit 15.

[0031] The flying object 16 is equipped with an image capturing device 16a capable of capturing images during flight and a temperature detecting device 16b capable of measuring temperature. Specifically, the image capturing device 16a is a camera, and the temperature detecting device 16b is an infrared sensor.

[0032] Next, a method for determining damage caused by falling snow executed by the system for determining damage caused by falling snow will be described with reference to Fig. 2. Fig. 2 is a process diagram of the method for determining damage caused by falling snow according to the embodiment. 2, the method 20 for determining damage caused by falling snow according to the embodiment is a method for determining whether or not a ground structure has damage caused by falling snow from power transmission equipment, and includes a pre-snow accumulation data acquisition step S21, a pre-snow accumulation detection step S22, a snow accumulation data acquisition step S23, a falling snow area identification step S24, a post-snow melt data acquisition step S25, a post-snow melt detection step S26, and a damage determination step S27. Each step will be described below in order.

[0033] The pre-snowfall data acquisition process in step S21 is a process in which the photographing means 16a photographs an area on the ground including a structure before snowfall, for example in autumn, and acquires pre-snowfall image data of this area, and the temperature detection means 16b acquires pre-snowfall temperature data.

[0034] Specifically, the structure is an agricultural greenhouse. The flight route of the aircraft 16 is set in advance. This flight route is a zigzag route, for example, flying along the longitudinal direction of one structure, and then repeatedly flying along the longitudinal direction of an adjacent structure. Furthermore, the aircraft 16 flies at a higher altitude than the power lines of the power transmission equipment, so that the power lines overhead are captured in the pre-snowfall image data. Therefore, the pre-snowfall image data is a plurality of images taken by the flying object 16 along the flight route.

[0035] Like the pre-snowfall image data, the pre-snowfall temperature data is a measurement value obtained by continuously measuring the temperature of a structure along the flight route by the flying object 16. The pre-snowfall image data and pre-snowfall temperature data are then transmitted to the communication unit 3 via the wireless communication path 17 and then stored in the input data storage unit 11.

[0036] The pre-snow accumulation detection step of step S22 is a step in which the damage detection unit 6 detects pre-snow accumulation damage to the structure from the pre-snow accumulation image data and pre-snow accumulation temperature data. In detail, the damage detection unit 6 creates a pre-snowfall image from a plurality of images taken by the flying object 16.

[0037] In addition, the damage detection unit 6 detects holes and discolored areas in the structure from the pre-snow accumulation image data, and detects areas of temperature change in the structure from the pre-snow accumulation temperature data. The detected holes, discolored areas, and temperature change areas are considered pre-snow accumulation damage. The pre-snow damage detection is performed using a known method such as edge processing. The pre-snow damage image and the pre-snow damage are stored in the damage storage unit 12. In addition to damage caused by snow falling from power transmission equipment in past winters, damage before snow accumulation also includes damage caused by stones or branches colliding with structures, and deterioration of the structures themselves over time.

[0038] The snow-covered data acquisition step of step S23 is a step in which the photographing means 16a photographs an area when snow is falling and acquires snow-covered image data of this area. The snow-covered image data is stored in the input data storage unit 11. In this step, the flight route of the flying object 16 and the photographing positions on this flight route are the same as those in the pre-snowfall data acquisition step of step S21.

[0039] The falling snow area identification step in step S24 is a step in which the falling snow area detection unit 7 creates a snow-covered image from the snow-covered image data and identifies the snow-covered area where snow has accumulated on the structure and the snow-falling area where snow has fallen on the structure. The snow-covered area is identified by the edge processing described above, or it may be identified as the same area as the region.

[0040] Furthermore, when snow falls, uneven snow marks are formed on the surface of the snow-covered area. Therefore, the snow-covered area is determined by the snow-covered area detection unit 7 detecting multiple snow marks within the snow-covered area as fallen snow locations, and then identifying the maximum area that includes these fallen snow locations. This maximum area can be determined, for example, using a known method that can convert point cloud data into a surface. The snow accumulation range, the snow falling range, and the snow falling location are stored in the snow falling range storage unit 13.

[0041] In the post-snowmelt data acquisition step of step S25, the photographing means 16a photographs an area 51 on the ground including a structure after the snow has melted, for example, in spring, and acquires post-snowmelt image data of this area. Additionally, in the post-snowmelt data acquisition step of step S25, the temperature detection means 16b detects the temperature of the area and acquires post-snowmelt temperature data. The post-snowmelt image data and post-snowmelt temperature data are stored in the input data storage unit 11. In this step, the flight route of the flying object 16, the photographing positions along this flight route, and the temperature measurement method are the same as those in the pre-snowfall data acquisition step of step S21.

[0042] The post-snowmelt detection step of step S26 is a step in which the damage detection unit 6 creates a post-snowmelt image from the post-snowmelt image data and the post-snowmelt temperature data, and also detects post-snowmelt damage to the structure. As in the pre-snow accumulation detection step of step S22, this post-snow melt damage is obtained by the damage detection unit 6 detecting holes and discolored areas in the structure from the post-snow melt image data, and detecting areas of temperature change in the structure from the post-snow melt temperature data. The detected holes, discolored areas, and temperature change areas are the pre-snow accumulation damage. The post-snow melt damage is then stored in the damage memory unit 12. Damage after snowmelt also includes damage caused by factors other than snow falling from power transmission equipment that occurred in past winters.

[0043] The damage determination step of step S27 is a step in which the determination unit 8 determines whether or not there is damage caused by snow falling from the power line, based on the damage before snow accumulation, the damage after snow melts, and the range of snow falling. In detail, the damage determination step in step S27 includes a difference portion specifying step in step S28 and a first determination step in step S29.

[0044] The difference part identification process of step S28 is a process in which the determination unit 8 subtracts the damage before snow melting from the damage after snow accumulation to identify the difference part between the damage before snow accumulation and the damage after snow melting. This difference part is stored in the determination result storage unit 14.

[0045] In the first determination step of step S29, the determination unit 8 determines that the structure has damage caused by falling snow when the difference location is included in the falling snow range, and outputs a first determination result. This first determination result is stored in the determination result storage unit 14. Note that, even when it is determined that there is no damage to the structure due to falling snow, the determination unit 8 may output a first determination result to that effect.

[0046] Next, the pre-snowfall image and the like output from the pre-snowfall detection step in step S22 to the first determination step in step S29 will be described in order with reference to FIGS. First, the pre-snow accumulation damage detected in the pre-snow accumulation detection step of step S22 will be described with reference to Fig. 3. Fig. 3 is a pre-snow accumulation image showing pre-snow accumulation damage to a structure. As shown in Figure 3, the pre-snowfall image F1 created by the damage detection unit 6 includes a rectangular structure 50, an area 51 on the ground that includes this structure 50, and a power line 60 that crosses above the structure 50. Among these, a plurality of structures 50 are present and are arranged in parallel within an area 51. Further, reference numeral 52 denotes pre-snow accumulation damage detected by the damage detection unit 6. This pre-snow accumulation damage 52 is displayed on the output unit 4, superimposed on the pre-snow accumulation image F1.

[0047] Next, the snow-covered area and the falling snow area identified in the falling snow area identification process of step S24 will be described with reference to Fig. 4 and Fig. 5, respectively. Fig. 4 is an image of snow covered area in which the snow-covered area has been identified. Fig. 5 is an image of snow covered area in which the falling snow area has been identified. Note that the components shown in Figs. 1 and 3 are given the same reference numerals in Figs. 4 and 5, and their description will be omitted. As shown in Figure 4, in the snow-covered image F2 created by the snow-falling area detection unit 7, multiple structures 50 are all covered in snow, so a snow-covered area 53 identical to area 51 (see Figure 3) is identified.

[0048] 5, in addition to the snow-covered area 53, a substantially trapezoidal fallen snow area 54 is identified in the snow-covered image F2. Reference numeral 55 denotes the fallen snow area detected by the fallen snow area detection unit 7. The snow-covered area 53, the fallen snow area 54, and the fallen snow area 55 are superimposed on the snow-covered image F2 and displayed on the output unit 4.

[0049] The post-snowmelt damage detected in the post-snowmelt detection process of step S26 will be described with reference to Fig. 6. Fig. 6 is a post-snowmelt image showing post-snowmelt damage to a structure. Note that the same reference numerals are used in Fig. 6 for the components shown in Figs. 1 and 3 to 5, and their description will be omitted. 6, in the post-snow melting image F3 created by the damage detection unit 6, post-snow melting damage is indicated by the reference numeral 56. The post-snow melting damage 56 is superimposed on the post-snow melting image F3 and displayed on the output unit 4.

[0050] Next, the differences identified in the difference identification process of step S28 will be described with reference to Fig. 7. Fig. 7 is a post-snow melt image showing the differences between the damage before snow accumulation and the damage after snow melt. Note that the same reference numerals are used in Fig. 7 for the components shown in Figs. 1 and 3 to 6, and their description will be omitted. 7, in the post-snow melting image F3, the difference between the pre-snow damage 52 identified by the determination unit 8 and the post-snow melting damage 56 is indicated by the reference numeral 57. The difference 57 is superimposed on the post-snow melting image F3 and displayed on the output unit 4.

[0051] Next, the first determination result output in the first determination process of step S29 will be described with reference to Fig. 8. Fig. 8 shows the first determination result. Note that the same reference numerals are used in Fig. 8 to denote the components shown in Figs. 1 and 3 to 7, and their description will be omitted. As shown in Fig. 8, in the post-snow melting image F3, only the difference areas 57, all or part of which are included in the fallen snow range 54, are shown as snow damage 58 caused by falling snow. In other words, the snow damage 58 is the first judgment result to be obtained. The first judgment result is stored in the judgment result storage unit 14 and is displayed on the output unit 4, superimposed on the post-snow melting image F3.

[0052] As described above, according to the snow damage determination method 20, the determination unit 8 identifies the differences 57 between the damage before snow accumulation 52 and the damage after snow melting 56, so that damage that occurred before snow accumulation can be eliminated. Furthermore, when the difference point 57 is included in the snowfall range 54, the judgment unit 8 judges that there is snowfall damage 58 caused by falling snow, so it is possible to accurately distinguish between damage caused by snow falling from the power line 60 and damage caused by stones or branches colliding with the structure or deterioration of the structure itself over time.

[0053] In addition, as shown in Fig. 8, snow damage 58 caused by falling snow can be specifically shown on the post-snowmelt image F3. This allows the electricity transmission and distribution company to accurately understand the need for compensation and its level, and to appropriately determine the compensation content when negotiating with the owner.

[0054] Next, a method 20A for determining damage caused by falling snow according to a modified example of the embodiment will be described with reference to Fig. 9. Fig. 9 is a process diagram of the method for determining damage caused by falling snow according to a modified example of the embodiment. As shown in Figure 9, the method 20A for determining damage due to falling snow in a modified example of the embodiment includes a step S30 for calculating the amount of snow accumulation immediately after the step S24 for identifying the range of falling snow, i.e., between the step S24 for identifying the range of falling snow and the step S25 for acquiring data after snow melting. Furthermore, the falling snow damage determination method 20A includes, in the damage determination step of step S27, a second determination step of step S31 after the first determination step of step S29. In FIG. 9, the steps from step S21, which is the pre-snowfall data acquisition step, to step S23, which is the snowfall data acquisition step, are omitted from illustration.

[0055] The snow accumulation amount calculation step of step S30 is a step in which the snow accumulation amount calculation unit 9 calculates the amount of snow adhering to the power transmission line 60 from the snow accumulation image data. The snow accumulation amount is stored in the snow accumulation amount calculation unit 9. In addition, the second determination step of step S31 is a step in which the determination unit 8 determines that the structure 50 has damage caused by falling snow when the amount of snow accumulation exceeds a preset snow accumulation threshold, and outputs a second determination result. The second determination result is stored in the determination result storage unit 14. Note that, even when it is determined that the structure 50 has no damage caused by falling snow, the determination unit 8 may output a second determination result to that effect.

[0056] Next, the calculation method in the snow accumulation amount calculation step in step S30 will be described with reference to Fig. 10. Fig. 10 is an enlarged image of a power transmission line included in an image of snow accumulation. As shown in FIG. 10, snow accumulation S consisting of at least one of snow and ice is attached to the power transmission line 60 included in the snow-covered image. Here, the diameter D of the power transmission line 60 60 is known, the diameter D of the power transmission line 60 can be calculated from the snow-covered image or snow-covered image data. 60 and the diameter D of the snow accumulation S s For example, by extracting and comparing the number of pixels corresponding to each of the above after binarizing them, the amount of snow accumulation S can be calculated as a volume ratio to the volume of the power transmission line 60.

[0057] Specifically, as shown in FIG. 10, when the appearance of snow accretion S is irregular, the diameter D s The number of pixels corresponding to the snow accumulation S is extracted and the extracted number of pixels is added up, thereby calculating the volume ratio of the snow accumulation S to the volume of the power transmission line 60 per desired length. Although not shown in the figure, when the appearance of the snow accumulation S is approximately cylindrical, the volume ratio of the snow accumulation S is the area ratio per unit length of the power transmission line 60 (D s / D 60 ) 2 It may also be possible to use the following.

[0058] In the above case, if the upper limit value of the volume ratio of snow accumulation S is preset as the snow accumulation threshold, in the second judgment process of step S31, if the volume ratio of snow accumulation S calculated by the snow accumulation amount calculation unit 9 exceeds the snow accumulation threshold, the judgment unit 8 outputs a second judgment result that the structure 50 has damage caused by falling snow.

[0059] In addition, if the first judgment result detects snow damage 58 and the second judgment result determines that there is no damage to the structure 50 caused by falling snow, it can be concluded that the snow S on the power line 60 has already fallen off and become snow damage 58, so it is best to adopt the first judgment result. Furthermore, if the first judgment result does not detect snow damage 58 and the second judgment result indicates that there is damage to the structure 50 caused by falling snow, it can be concluded that although the snow accumulation S has not yet fallen, there is a risk that snow damage 58 may occur in the future, and therefore, after a certain period of time has passed, the steps from the snow accumulation data acquisition step of step S23 onwards may be repeated.

[0060] As described above, according to the snow fall damage determination method 20A, the presence or absence of damage caused by falling snow is determined in two stages: a first determination process and a second determination process, thereby improving the reliability of the first determination result and the second determination result output by the determination unit 8 compared to when only the first determination process is executed. In particular, when the first determination result and the second determination result are not contradictory, the reliability is high. The effects and advantages of the falling snow damage determination method 20A other than those described above are similar to those and advantages of the falling snow damage determination method 20.

[0061] The method for determining damage caused by falling snow according to the present invention is not limited to the examples shown in the following. For example, in the pre-snow accumulation data acquisition step S21 and the post-snow melt data acquisition step S25, the acquisition of pre-snow accumulation temperature data and post-snow melt temperature data by the temperature detection means 16b may be omitted. Furthermore, as in the falling snow damage determination method 20, if the snow accumulation amount calculation process of step S30 and the second determination process of step S31 are not executed, the snow accumulation amount calculation unit 9 and the snow accumulation amount memory unit 15 of the falling snow damage determination system 1 may be omitted. Furthermore, in the method 20A for determining snow damage due to falling snow, the snow accumulation amount calculation process of step S30 may be executed immediately after the snow falling range determination process of step S24, instead of being executed immediately before the snow falling range determination process of step S24, i.e., between the snow accumulation data acquisition process of step S23 and the snow falling range determination process of step S24. [Industrial Applicability]

[0062] The present invention can be used as a method for determining whether or not a structure on the ground has been damaged by falling snow from power transmission equipment. [Explanation of symbols]

[0063] 1...Snow fall damage determination system 2...Snow fall damage determination device 3...Communication unit 4...Output unit 5...Control unit 6...Damage detection unit 7...Snow fall range detection unit 8...Determination unit 9...Snow accumulation amount calculation unit 10...Memory unit 11...Input data memory unit 12...Damage memory unit 13...Snow fall range memory unit 14...Determination result memory unit 15...Snow accumulation amount memory unit 16...Air vehicle 16a...Photographing means 16b...Temperature detection means 17...Wireless communication path 20, 20A...Snow fall damage determination method 50...Structure 51...Area 52...Damage before snow accumulation 53...Snow accumulation range 54...Snow fall range 55...Snow fall location 56...Damage after snow melts 57...Difference area 58...Snow fall damage 60...Power transmission line

Claims

1. A method for determining whether or not a structure on the ground is damaged by falling snow from a power transmission facility, comprising: a pre-snowfall data acquisition step in which an imaging means mounted on the aircraft images an area on the ground including the structure before snow accumulation and acquires pre-snowfall image data of the area; a pre-snow accumulation detection step in which a damage detection unit detects pre-snow accumulation damage to the structure from the pre-snow accumulation image data; a snowfall data acquisition step in which the photographing means photographs the area when snow is falling and acquires snowfall image data of the area; a snow falling area detection unit for identifying a snow falling area where the snow has fallen on the structure from the snow accumulation image data; a post-snowmelt data acquisition step in which the photographing means photographs the area after the snow has melted and acquires post-snowmelt image data of the area; a post-snowmelt detection step in which the damage detection unit detects post-snowmelt damage to the structure from the post-snowmelt image data; A method for determining snow damage, characterized in that the determination unit includes a damage determination process for determining whether or not the damage exists based on the damage before snow accumulation, the damage after snow melting, and the range of falling snow.

2. The damage determination step includes a difference specifying step and a first determination step, The difference part identification step includes the determination unit comparing the pre-snow accumulation damage and the post-snow melting damage to identify a difference part between the pre-snow accumulation damage and the post-snow melting damage, The method for determining snow damage as described in claim 1, characterized in that the first judgment process involves the judgment unit determining that the structure has damage caused by falling snow when the difference area is included in the falling snow range, and outputting a first judgment result.

3. The structure is a greenhouse, The aircraft is equipped with a temperature detection means in addition to the photographing means, In the pre-snowfall data acquisition step, in addition to acquiring the pre-snowfall image data, the temperature detection means detects the temperature of the area to acquire pre-snowfall temperature data; In the post-snowmelt data acquisition step, in addition to acquiring the post-snowmelt image data, the temperature detection means detects the temperature of the area to acquire post-snowmelt temperature data; In the pre-snow accumulation detection step, the damage detection unit detects holes and discolored areas that have occurred in the structure from the pre-snow accumulation image data, and detects temperature change areas that have occurred in the structure from the pre-snow accumulation temperature data; The method for determining snow damage caused by falling snow described in claim 1 or claim 2, characterized in that the post-snow melting detection process involves the damage detection unit detecting the holes and the discolored areas from the post-snow melting image data, and detecting the temperature change areas from the post-snow melting temperature data.

4. A snow accumulation amount calculation step is provided immediately before or immediately after the snow falling area determination step, a second determination step is provided after the first determination step, The snow accumulation amount calculation step includes a snow accumulation amount calculation unit calculating an amount of snow that adheres to the power transmission line that constitutes the power transmission facility from the snow accumulation image data, The method for determining snow damage caused by falling snow, as described in claim 2, characterized in that the second judgment process involves the judgment unit determining that the structure has damage caused by falling snow when the amount of snow accumulation exceeds a predetermined snow accumulation threshold, and outputting a second judgment result.

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