Water level determination system

Abstract

To provide a water level determination system that can determine a precise water level.SOLUTION: A water level determination system 10 includes: an image acquisition unit 11 for acquiring an image obtained by imaging a part as a target of water level determination; a detection unit 12 for detecting a part which shows water in each of a plurality of regions for water level determination set in different positions of the acquired image; and a water level determination unit 13 for determining whether the regions for water level determination are to be used to determine a water level on the basis of the result of detection, and determining a water level by using the result of detection for a region for water level determination that has been determined to be used for the determination.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water level determination system for determining the water level of a river or the like. [Background technology]

[0002] Conventionally, it has been proposed to determine the water level of a river from an image obtained by capturing an image of the river. For example, Patent Document 1 shows that the water level is determined by detecting a portion in which water is captured in a region for determining the water level set in an image obtained by capturing an image of the river. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 107528 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to determine the water level more appropriately, it is conceivable to set multiple regions for determining the water level in the image and determine the water level. However, if any of the regions is covered by obstacles such as plants and does not show the water, it is not possible to detect the part showing the water. In other cases, not all regions are necessarily suitable for determining the water level. In such cases, the accuracy of the determined water level may be poor.

[0005] The present invention has been made in consideration of the above, and has an object to provide a water level determination system that can determine the water level with high accuracy. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the water level determination system of the present invention comprises an image acquisition unit that acquires an image obtained by imaging the location to be determined for the water level, a detection unit that detects areas in which water is reflected in each of a plurality of water level determination areas set at different positions in the image acquired by the image acquisition unit, and a water level determination unit that determines whether or not each of the plurality of water level determination areas will be used for determining the water level based on the detection results by the detection unit, and determines the water level using the detection results of the water level determination areas determined to be used for determining the water level.

[0007] In the water level determination system according to the present invention, when determining the water level, it is determined whether or not each of the multiple water level determination regions is used for determining the water level. As a result, the water level is determined using only the detection results of the water level determination regions that are suitable for determining the water level. Therefore, the water level determination system according to the present invention can determine the water level with high accuracy. Effect of the Invention

[0008] According to the present invention, the water level can be determined with high accuracy. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a water level determination system according to an embodiment of the present invention. [Diagram 2] 1 is an example of an image used for determining a water level. [Diagram 3] 1 is an example of an image used for determining a water level. [Figure 4] FIG. 13 is a diagram showing a portion of a virtual water level meter in which water is reflected and a detected water level. [Diagram 5] FIG. 13 is a diagram showing a divided virtual water level gauge. [Figure 6] FIG. 13 is a diagram for explaining determination of a water level using divided regions. [Figure 7] 13 is a flowchart showing how to determine a water level using divided regions. [Figure 8] FIG. 13 is a diagram showing the deviation of a virtual water level gauge with respect to the direction of the water level. [Figure 9] 13 is a graph showing an example of an error between virtual water gauges. [Figure 10] 1 is a table showing an example of average values ​​of relative errors between virtual water level gauges. [Figure 11] 10 is a flowchart showing the determination of a reference virtual water level meter and a correction value. [Figure 12] FIG. 13 is a diagram showing an example of values ​​(measured values) and corrected values ​​calculated for each virtual water level gauge. [Figure 13] 13 is a flowchart showing the exclusion of a virtual water level gauge. [Figure 14] 1 is a table showing an example of relative errors between virtual water level gauges. [Figure 15] 13 is a flowchart showing the exclusion of a virtual water level gauge. [Figure 16] 1 is an example of an image used for determining a water level. [Figure 17] 1 is a table showing an example of relative errors between virtual water level gauges. [Figure 18] 1 is an example of an image used for determining a water level. [Figure 19] 1 is a table showing an example of relative errors between virtual water level gauges. [Figure 20] 13 is a flowchart showing a process for determining whether or not the water level can be determined. [Figure 21] 4 is a flowchart showing a process executed in the water level determination system according to the embodiment of the present invention. [Figure 22] 1 is a diagram illustrating a hardware configuration of a water level determination system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a water level determination system according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals and duplicated explanations will be omitted.

[0011] FIG. 1 shows a water level determination system 10 according to this embodiment. The water level determination system 10 is a system (device) that determines the water level of a river or the like. The water level determined by the water level determination system 10 is used, for example, to detect river flooding. Future water levels may be predicted from the water level determined by the water level determination system 10 using artificial intelligence (AI) or the like. Information such as precipitation may be used for the prediction.

[0012] The water level determination system 10 is configured by a computer such as a PC (personal computer) or a server device. The water level determination system 10 may be configured by a plurality of computers, i.e., a computer system. The water level determination system 10 has a communication function and can transmit and receive information to and from other devices.

[0013] The water level determination system 10 determines the water level based on an image obtained by capturing an image of a location to be determined for water level by the camera 20. The camera 20 may be an existing camera. The camera 20 is positioned in advance and fixedly installed so that it can capture an image of the location to be determined for water level. The image is captured by the camera 20, for example, at regular intervals. The time interval between images captured by the camera 20 may be the same as the time interval for determining the water level by the water level determination system 10. For example, the time interval may be several seconds, several minutes, or several hours. FIG. 2 shows an example of an image 100 captured by the camera 20.

[0014] The camera 20 may have a communication function or may be connected to a device having a communication function, and may transmit images to the water level determination system 10. The communication function may be an existing one. The transmission is performed, for example, every time an image is captured.

[0015] Next, a description will be given of the functions of the water level determination system 10 according to this embodiment. As shown in FIG.

[0016] The image acquisition unit 11 is a functional unit that acquires an image obtained by capturing an image of a location to be determined for the water level. For example, the image acquisition unit 11 receives an image transmitted from the camera 20 and acquires the image. The image acquisition unit 11 may also acquire an image by a method other than the above. The image acquisition unit 11 outputs the acquired image to the detection unit 12.

[0017] The detection unit 12 is a functional unit that detects the portion in which water is reflected in each of a plurality of water level determination regions set at different positions in the image acquired by the image acquisition unit 11. The detection unit 12 may detect an obstacle in each of the plurality of water level determination regions that is used for determining whether or not each of the plurality of water level determination regions is to be used for water level determination by the water level determination unit 13. The detection unit 12 may detect the portion in which water is reflected in each divided region obtained by dividing the water level determination region in the water level direction.

[0018] For example, the detection unit 12 performs detection as follows. The detection unit 12 stores the positions of a plurality of regions for water level determination in an image acquired by the image acquisition unit 11. The regions for water level determination are used to determine the water level, and are hereinafter also referred to as virtual water level gauges. FIG. 2 shows an example of a virtual water level gauge 200 set in the image 100. In FIG. 2, three virtual water level gauges 200 are set at different positions in the image 100. The virtual water level gauges 200 are, for example, rectangular regions, and are set as follows. The virtual water level gauges 200 are provided at positions in the image 100 where the boundaries of the water portion 300 of the river or the like that is the subject of the water level determination are reflected when the water level rises or falls. For example, as shown in FIG. 2, the virtual water level gauges 200 are set at the vertical artificial portions that are the ends in the width direction of the river or the like that is the subject of the water level determination. As a result, the portion 310 occupied by water in the virtual water level gauge 200 rises in accordance with the rise in the water level of the river or the like. A plurality of virtual water level gauges 200 are set at different positions in the flow direction of a river or the like.

[0019] The virtual water level gauges 200 are set in advance by, for example, an administrator of the water level determination system 10. Specifically, an image is displayed in a browser and four points are clicked to specify four end points for each virtual water level gauge 200 on the coordinate axis of the image, thereby setting the virtual water level gauges 200. The virtual water level gauges 200 may also be set by rotating or moving a prepared rectangular figure three-dimensionally on the image 100. The virtual water level gauges 200 may also be set by other methods. The virtual water level gauges 200 may have a shape other than a rectangle.

[0020] The detection unit 12 inputs the image 100 from the image acquisition unit 11. The detection unit 12 detects a portion 310 in which water is reflected (i.e., a portion corresponding to the water surface) in each of the virtual water level gauges 200 in the image 100. The detection unit 12 may also detect a portion 400 in which an obstacle is reflected in each of the virtual water level gauges 200 in the image 100. The obstacle is, for example, a plant portion as shown in FIG. 3. If there is an obstacle between the camera 20 and the portion to be imaged that corresponds to the virtual water level gauge 200, the water portion of a river or the like will not be properly reflected in the virtual water level gauge 200. The obstacle is not limited to a plant, but may be anything that can be an obstacle in judging the water level. What is considered to be an obstacle is preset, for example, by an administrator of the water level judgment system 10.

[0021] The detection unit 12 performs the above detection using, for example, a trained model stored in advance. The trained model is for segmentation generated by machine learning. The trained model receives an image and outputs information indicating a classification for each pixel of the input image. The classification indicates what is reflected in the pixel. The classification may be any classification that can distinguish between water, obstacles, and other objects. Alternatively, the trained model may detect the area of ​​each classification in the image as a polygonal area such as a rectangular overlap. Also, a different trained model may be used for each classification. For example, the obstacle area may be detected using a trained model that detects the area as a rectangular overlap. The above detection using the trained model may be performed by an existing method. As described later, the virtual water level meter 200 may take into account the portion 310 in which water is reflected for each divided area divided in the water level direction (the direction in which the water level changes). The above detection for each pixel is detection for each divided area.

[0022] The detection unit 12 may perform detection by a method other than the above. The detection unit 12 outputs information indicating the detection result to the water level determination unit 13. The information indicating the detection result is, for example, information indicating the classification of each pixel of the virtual water level gauge 200.

[0023] The water level determination unit 13 is a functional unit that determines whether or not each of the multiple water level determination regions is to be used for water level determination based on the detection result by the detection unit 12, and determines the water level using the detection result of the water level determination region determined to be used for water level determination. The water level determination unit 13 may calculate statistics of values ​​related to the water level in each of the multiple water level determination regions based on the detection result by the detection unit 12, and determine whether or not each of the multiple water level determination regions is to be used for water level determination based on the calculated statistics. The water level determination unit 13 may store a reference difference value of values ​​related to the water level between the multiple water level determination regions, and determine the water level using the reference difference value. The water level determination unit 13 may calculate a difference value of values ​​related to the water level between the multiple water level determination regions based on the detection result by the detection unit 12, and determine whether or not each of the multiple water level determination regions is to be used for water level determination based on the calculated difference value.

[0024] The water level determination unit 13 may determine, depending on the detection result of the detection unit 12, that each divided area is an area related to water, non-water, or indefinite, and determine the water level based on the determination result and the positional relationship of the divided areas.

[0025] For example, the water level determination unit 13 determines the water level as follows. The water level determination unit 13 inputs information indicating the detection result from the detection unit 12. The water level determination unit 13 first calculates a value used for determining the water level for each virtual water level gauge 200 from the detection result by the detection unit 12. For example, the water level determination unit 13 calculates the ratio of the portion 310 in which water is reflected to the area of ​​the virtual water level gauge 200 for each virtual water level gauge 200. Specifically, the water level determination unit 13 calculates the ratio of the pixels in the portion 310 in which water is reflected to the pixels of the entire virtual water level gauge 200 as the value used for determining the water level. The value used for determining the water level indicates the water level that can be determined from one virtual water level gauge 200. For example, if 70% of the virtual water level gauge 200 is considered to be water, the water level is determined from the virtual water level gauge 200 to be 70% from the bottom of the virtual water level gauge 200.

[0026] However, in detection by the detection unit 12, depending on the image obtained by the camera 20, there is a risk that an area in the virtual water level gauge 200 that should be detected as the area 310 reflecting water may become an undetected area 500 as shown on the left side of Fig. 4. The undetected area 500 is an area that was not detected as the area 310 reflecting water due to, for example, light reflection on the water surface. In this case, if the calculation is simply performed based on the area ratio as described above, the water level will be determined to be lower than the actual water level 320 (water surface) by the sum 510 of the undetected areas 500 as shown on the right side of Fig. 4.

[0027] To solve this problem, the water level determination unit 13 may calculate a value used for determining the water level using the detection results for each divided area 210 obtained by dividing the virtual water level gauge 200 in the water level direction as shown in Fig. 5. The divided areas 210 are rectangular areas obtained by equally dividing the virtual water level gauge 200 into a preset number of areas in the water level direction. The water level direction may be set when setting the virtual water level gauge 200. In the example shown in Fig. 5, the virtual water level gauge 200 is divided into ten divided areas 210. The water level determination unit 13 stores in advance how to divide the virtual water level gauge 200 into the divided areas 210.

[0028] The water level determination unit 13 calculates the ratio of the portion 310 in which water is reflected for each divided region 210 in the same manner as described above. Based on the calculated ratio, the water level determination unit 13 determines whether water has reached each divided region 210, i.e., whether the water surface is above the divided region 210, and calculates a value to be used for determining the water level. For example, the water level determination unit 13 compares the ratio calculated for each divided region 210 with a preset threshold value, and among the divided regions 210 in which the ratio exceeds the threshold value, the water level determination unit 13 sets a value indicating that the water level is present in the portion of the uppermost divided region 210 (more specifically, the upper end of the divided region 210) as the value to be used for determining the water level. In other words, the water level determination unit 13 sets the portion of the divided region 210 as the water level for the virtual water level gauge 200.

[0029] Furthermore, to perform a more accurate determination, the water level determination unit 13 may calculate a value used to determine the water level of the virtual water level gauge 200 using the divided regions 210 as follows. For each divided region 210, if the proportion of the portion 310 in which water is reflected in the divided region 210 is significantly high or low, it is easy to determine whether water is present or not. However, due to the above-mentioned detection missed region 500, the determination may not be easy and the result may be indecisive (indeterminate). This calculation takes such cases into consideration.

[0030] The calculation by the water level determination unit 13 will be explained with reference to the diagram of the virtual water level gauge 200 in Fig. 6 and the flowchart in Fig. 7. First, the water level determination unit 13 divides the virtual water level gauge 200 into N divided areas 210 (stripes) (L1 to LN) based on pre-stored information (S101). As shown in Fig. 6(a), the divided area 210 located at the lowest position is L1, and the divided area 210 located at the highest position is LN (L10 in the case of Fig. 6(a)). Next, the water level determination unit 13 calculates an evaluation value for each divided area 210, which is the proportion of the portion 310 in which water is reflected.

[0031] Next, the water level determination unit 13 compares the evaluation value of L1, which is the divided region 210 located at the lowest position, with a pre-stored threshold value X0 (S102). The threshold value X0 is used to determine whether L1, which is the divided region 210 located at the lowest position, is a water-related region or a non-water-related region (i.e., not a water-related region) as shown in FIG. 6(a), and a value corresponding to the evaluation value is set in advance as the threshold value X0. If it is determined that the evaluation value is equal to or greater than the threshold value X0 as a result of the comparison (YES in S102), the water level determination unit 13 determines that L1 is a water-related region (S103). If it is determined that the evaluation value is less than the threshold value X0 as a result of the comparison (NO in S102), the water level determination unit 13 determines that L1 is a non-water-related region (S104).

[0032] Next, the water level determination unit 13 performs the following determination using the evaluation value for the divided regions 210 L2 to LN other than L1. The determination is performed in order from the bottom region L2 among L2 to LN. First, the water level determination unit 13 compares the evaluation value with a pre-stored threshold value X2 (S105). As shown in FIG. 6(a), the threshold value X2 is used to determine whether or not the divided regions 210 L2 to LN other than L1 are regions related to water, and a value corresponding to this is set in advance as the threshold value X2. In addition, a value equal to or greater than the threshold value X0 is set as the threshold value X2. If it is determined that the evaluation value is equal to or greater than the threshold value X2 as a result of the comparison (YES in S105), the water level determination unit 13 determines that Li (any of L2 to LN to be determined) is a region related to water (S106).

[0033] If it is determined that the evaluation value is less than the threshold value X2 as a result of the comparison (NO in S105), the water level determination unit 13 then compares the evaluation value with a pre-stored threshold value X1 (S107). As shown in FIG. 6(a), the threshold value X1 is used to determine whether or not the divided regions 210 L2 to LN other than L1 are non-water related regions, and a value corresponding to this is set in advance as the threshold value X1. In addition, a value equal to or less than the threshold value X0 is set as the threshold value X1. If it is determined that the evaluation value is less than the threshold value X1 as a result of the comparison (YES in S107), the water level determination unit 13 determines that Li is a non-water related region (S108).

[0034] If it is determined that the evaluation value is equal to or greater than the threshold value X1 (NO in S107), the water level determination unit 13 determines that Li (any of L2 to LN to be determined) is an indefinite region. In this case, the water level determination unit 13 refers to the determination result of Li-1, which is the divided region 210 below Li, and determines that Li is the same region as the determination result of Li-1 (S109).

[0035] That is, if Li-1 is determined to be a water-related area (YES in S109), the water level determination unit 13 determines Li to be a water-related area (S110). If Li-1 is determined to be a non-water-related area (NO in S109), the water level determination unit 13 determines Li to be a non-water-related area (S111).

[0036] When the above determination is performed for L2 to LN, all divided regions 210, L1 to LN, are determined to be water-related or non-water-related regions. The water level determination unit 13 sets a value indicating that the water level is present in the uppermost divided region 210 among the divided regions 210 determined to be water-related regions as the value to be used for determining the water level. In other words, the water level determination unit 13 sets the portion of the divided region 210 in question as the water level for the virtual water level gauge 200.

[0037] According to the above determination, in the example shown in Fig. 6(b), the part L5 is determined to be the position of the water level. Also, in the example shown in Fig. 6(c), the part L8 is determined to be the position of the water level. As described above, the water level determination unit 13 may determine each divided area 210 as an area related to water, non-water, or indefinite according to the detection result of the detection unit 12, and determine the water level based on the determination result and the positional relationship of the divided areas. The water level determination unit 13 determines the final water level from the value used to determine the water level for each virtual water level gauge 200 calculated as described above.

[0038] The water level determination unit 13 judges whether or not to use each of the virtual water level gauges 200 for judging the water level. The water level determination unit 13 judges the final water level using the value used for judging the water level of the virtual water level gauge 200 that has been judged to be used for judging the water level.

[0039] For example, the water level determination unit 13 calculates statistics of values ​​related to the water level in each of the multiple virtual water gauges 200, and uses the calculated statistics to determine the water level for each virtual water gauge 200. Specifically, the water level determination unit 13 calculates variance or standard deviation as a statistic from the values ​​used to determine the water level for each virtual water gauge 200. The water level determination unit 13 uses the calculated statistics to detect outliers from the values ​​used to determine the water level for each virtual water gauge 200. The detection of outliers may be performed by an existing method. In other words, the water level determination unit 13 excludes the virtual water gauge 200 related to the outlier from the water level determination (determines that a virtual water gauge 200 other than the virtual water gauge 200 related to the outlier should be used to determine the water level).

[0040] The water level determination unit 13 determines the final water level from values ​​other than the excluded outliers. For example, the water level determination unit 13 determines the median value of the values ​​other than the excluded outliers as the final water level determination result. Alternatively, the water level determination unit 13 determines the average value of the values ​​other than the excluded outliers as the final water level determination result.

[0041] The water level determination unit 13 may determine the virtual water level gauge 200 to be used for determining the water level by a method other than the above. When the virtual water level gauge 200 is set manually, etc., a slight error may occur in the water level determined from each virtual water level gauge 200. FIG. 8 shows an example of three virtual water level gauges 200, A, B, and C, viewed from a direction perpendicular to the water level direction (the direction in which the water level changes). It is desirable to set the virtual water level gauge 200 so that its lower end is located at the river bottom (the position where the water level is 0) and its upper end is located at the top of the expected water level. However, as shown in FIG. 8, the position of the virtual water level gauge 200 in the water level direction may not necessarily be an appropriate position.

[0042] However, this deviation is a steady error that is not dependent on the time (day and time of day) or other environmental conditions. Therefore, this deviation can be corrected. For example, by measuring the water level of the virtual water level gauge 200 as described above for a certain period of time under normal circumstances and taking the average, it is possible to calculate the steady difference between one virtual water level gauge 200 and another virtual water level gauge 200, using the other virtual water level gauge 200 as the reference.

[0043] FIG. 9 shows a graph of an example of the error between the virtual water gauges 200. FIG. 9(a) shows a graph of the change over time of the water level calculated from three virtual water gauges 200, A, B, and C. The water level is a value used to determine the water level for the virtual water gauge 200, calculated by the method described above. A higher water level value indicates a higher water level. FIG. 9(b) shows a graph of the change over time of the difference in the water level calculated from two virtual water gauges 200. As shown in FIG. 9, even if there is a difference in the water levels calculated from each virtual water gauge 200, the difference is a steady value.

[0044] The water level determination unit 13 may store a reference difference value of the values ​​related to the water level between a plurality of virtual water gauges 200, and determine the water level using the reference difference value. The water level determination unit 13 determines (selects) and stores in advance the virtual water gauge 200 serving as a reference and a correction value which is the reference difference value described above, as described below, and uses them to determine the water level.

[0045] The water level determination unit 13 calculates a value related to the water level for each virtual water level gauge 200 for a certain period of time during normal times (before the water level is determined). The value related to the water level is a value used in determining the water level described above, and may be calculated by the method described above. The water level determination unit 13 calculates the average value (time average) of the relative errors between the calculated values ​​of the virtual water level gauges 200. The water level determination unit 13 calculates the average value of the relative errors for each combination of two virtual water level gauges 200 out of the multiple virtual water level gauges 200. FIG. 10 shows a table of an example of the average value of the calculated relative errors when there are five virtual water level gauges 200, A to E. The values ​​in the table in FIG. 10 are the average values ​​of the relative errors of the values ​​related to the water level with respect to the other virtual water level gauges 200 when each virtual water level gauge 200 is used as a reference. Row B, column C of the table in FIG. 10 indicates that the average value of the virtual water level gauge 200 of C - the average value of the virtual water level gauge 200 of B is -1.

[0046] The water level determination unit 13 calculates the sum of the absolute values ​​of the average values ​​of the relative errors for each virtual water gauge 200 with respect to the other virtual water gauges 200. The water level determination unit 13 determines the virtual water gauge 200 with the smallest calculated sum as the reference virtual water gauge 200. The water level determination unit 13 determines the average value of the relative errors between the water level values ​​of the reference virtual water gauge 200 and the other virtual water gauges 200 as a correction value. As shown in FIG. 10, the correction value is determined for each of the other virtual water gauges 200.

[0047] The process by which the water level determination unit 13 determines the reference virtual water level gauge 200 and the correction value will be described with reference to the flowchart in Fig. 11. First, the water level determination unit 13 calculates a value related to the water level for each virtual water level gauge 200 at time t at a fixed time interval Δt in a fixed period T. The water level determination unit 13 calculates the water level value W it ,W jt Relative error ΔW ijt =W it -W jt The relative error ΔW is calculated (S201). ijt is calculated for all combinations of the virtual water level gauges 200 and all times t.

[0048] Next, the water level determination unit 13 calculates the relative error ΔW ijt Time average ΔW ij =Σ t ΔW ijt Next, the water level determination unit 13 calculates the relative error ΔW ijt Time average ΔW ij The cumulative relative error Z is the sum of the absolute values ​​of i =Σ j |ΔW ij | is calculated (S203). i is calculated for all virtual water gauges 200.

[0049] The water level determination unit 13 calculates the integrated relative error Z i is minimized.k =min(Z 1 ,…,Z N The water level determination unit 13 determines the k-th virtual water level gauge 200 as the reference virtual water level gauge 200 (S205). The water level determination unit 13 also determines the relative error ΔW kjt Time average ΔW kj Correction value C kj (S206). The water level determination unit 13 stores the virtual water level indicator 200 and the correction value as a reference, and uses them for determining the final water level.

[0050] Next, the final water level determination using the reference virtual water level gauge 200 and the correction value will be described. As described above, the water level determination unit 13 calculates the value used for determining the water level for each virtual water level gauge 200. Basically, the water level determination unit 13 determines the virtual water level gauge 200 whose value used for determination is the median value among the virtual water level gauges 200 as the virtual water level gauge 200 to be used for determining the water level. FIG. 12(a) shows an example of calculated values ​​(measured values) when there are five virtual water level gauges 200, A to E. In FIG. 12(a), if the median value is adopted without correction, the virtual water level gauge 200 B is determined as the virtual water level gauge 200 to be used for determining the water level. However, this is not adopted in this embodiment.

[0051] The water level determination unit 13 corrects the values ​​of the virtual water level gauges 200 other than the reference virtual water level gauge 200 with the correction value. The water level determination unit 13 calculates a corrected value by adding the correction value corresponding to the virtual water level gauge 200 to the value of each virtual water level gauge 200. The water level determination unit 13 determines the virtual water level gauge 200 that is the median value of the corrected values ​​as the virtual water level gauge 200 to be used for determining the water level. FIG. 12(b) shows an example of the value shown in FIG. 12(a) corrected with the correction value shown in FIG. 10 as the virtual water level gauge 200 of B. In this case, the median value is the value (52) of the virtual water level gauge 200 of C, and the virtual water level gauge 200 of C is determined as the virtual water level gauge 200 to be used for determining the water level.

[0052] The water level determination unit 13, for example, sets the value of the virtual water level gauge 200 determined as the virtual water level gauge 200 used to determine the water level as the value indicating the result of the water level. That is, the water level determination unit 13 sets a plausible representative value taking into consideration stationary errors as the value indicating the result of the water level. Note that, when using a reference virtual water level gauge 200 and a correction value, the determination of the virtual water level gauge 200 used to determine the water level and the final determination of the water level according to the determination may be performed by a method other than the above. For example, a plurality of virtual water level gauges 200 may be adopted as the virtual water level gauges 200 used to determine the water level, and the average value of these values ​​may be set as the value indicating the result of the water level.

[0053] After the camera 20 is installed, if an extended period of time passes, an object may unexpectedly overlap the virtual water level gauge 200 due to the growth of plants, etc., as shown in Fig. 3. This may cause the portion 310 of the virtual water level gauge 200 that shows water to be unable to be detected correctly.

[0054] Therefore, the water level determination unit 13 may determine whether or not to use the virtual water level gauge 200 for determining the water level based on the portion 400 in which the obstacle is reflected in the virtual water level gauge 200. For example, the water level determination unit 13 calculates the ratio of the obstacle to the area of ​​the virtual water level gauge 200 for each virtual water level gauge 200, for example, as a percentage. Specifically, the water level determination unit 13 calculates the ratio of pixels in the portion 400 in which the obstacle is reflected to the pixels of the entire virtual water level gauge 200. The water level determination unit 13 compares the ratio of the obstacle calculated for each virtual water level gauge 200 with a preset threshold value, and if the ratio of the obstacle is equal to or greater than the threshold value, excludes the virtual water level gauge 200 from the virtual water level gauges 200 to be used for determining the water level. Alternatively, if an obstacle is captured on the virtual water level gauge 200, for example if the virtual water level gauge 200 includes a rectangular area corresponding to the obstacle, the water level determination unit 13 may exclude that virtual water level gauge 200 from the virtual water level gauges 200 used to determine the water level. The water level determination unit 13 may determine the water level as described above after excluding the virtual water level gauge 200. Note that if the excluded virtual water level gauge 200 is the reference virtual water level gauge 200, the water level determination unit 13 may newly determine the reference virtual water level gauge 200 from the virtual water level gauges 200 that have not been excluded.

[0055] The exclusion of the virtual water level gauge 200 by the water level determination unit 13 will be described with reference to the flowchart of FIG. 13. The water level determination unit 13 performs the following process for each virtual water level gauge 200. The water level determination unit 13 calculates the ratio of obstacles to the area of ​​the virtual water level gauge 200. The water level determination unit 13 compares the ratio of obstacles with a preset threshold value (S301). If it is determined that the ratio of obstacles is less than the threshold value as a result of the comparison (YES in S301), the water level determination unit 13 sets the virtual water level gauge 200 as the virtual water level gauge 200 to be used for determining the water level (S302). That is, in this case, the water level determination unit 13 includes the virtual water level gauge 200 in the calculation target for the subsequent water level determination. If it is determined that the ratio of obstacles is equal to or greater than the threshold value as a result of the comparison (NO in S301), the water level determination unit 13 excludes the virtual water level gauge 200 from the virtual water level gauges 200 to be used for determining the water level (S303). That is, in this case, the water level determination unit 13 excludes the virtual water level indicator 200 from the targets of calculations for determining the water level thereafter.

[0056] As shown in FIG. 10, if a long period of time passes after a steady relative error between the virtual water level gauges 200 is grasped, there is a risk that the portion 310 of the virtual water level gauge 200 showing water may no longer be detected correctly due to factors other than obstacles that can be detected by the detection unit 12 (for example, an object that has not been learned in advance may become an obstacle).

[0057] Therefore, the water level determination unit 13 may calculate a difference value between the values ​​relating to the water level between the virtual water gauges 200 based on the detection results by the detection unit 12, and determine whether or not to use the calculated difference value for determining the water level for each of the multiple water level determination regions. For example, the water level determination unit 13 calculates the relative error between the virtual water gauges 200 of the calculated value used for determining the water level. The water level determination unit 13 calculates the relative error for each combination of two virtual water gauges 200 out of the multiple virtual water gauges 200. The relative error may be calculated using the corrected value described above. Fig. 14 shows a table of an example of the relative error calculated when there are five virtual water gauges 200, A to E.

[0058] The water level determination unit 13 determines whether the calculated relative error is an abnormal value. For example, the water level determination unit 13 compares the absolute value of the calculated relative error with a preset threshold value (for example, 25 in the example shown in FIG. 14), and determines that the calculated relative error is an abnormal value if the absolute value of the relative error is equal to or greater than the threshold value. In FIG. 14, the threshold value for determining an abnormal value is shown in bold.

[0059] The water level determination unit 13 counts the number of relative errors determined to be abnormal values ​​for each virtual water gauge 200 (the number of other virtual water gauges 200). The water level determination unit 13 compares the counted number with a preset threshold value (for example, 3 in the example shown in FIG. 14). If the counted number is equal to or greater than the threshold value, the water level determination unit 13 determines that the virtual water gauge 200 is the cause of the outlier and excludes the virtual water gauge 200 from the virtual water gauges 200 used to determine the water level. In the example shown in FIG. 14, the number of relative errors determined to be abnormal values ​​for C's virtual water gauge 200 is 4, which is equal to or greater than the threshold value. Therefore, C's virtual water gauge 200 is excluded from the virtual water gauges 200 used to determine the water level.

[0060] The water level determination unit 13 may also determine whether or not to use each of the virtual water level gauges 200 for determining the water level, based on the time series values ​​used for determining the water level of each of the virtual water level gauges 200. The water level determination unit 13 determines whether the calculated value used for determining the water level has not changed over the entire period going back a preset certain period (Tc) from the current time point and is a minimum value (e.g., 0) or a maximum value (e.g., 100). If either of these is true, the water level determination unit 13 excludes the virtual water level gauge 200 from the virtual water level gauges 200 used for determining the water level. This is because, in these cases, it is considered that the virtual water level gauge 200 cannot be used for determining the water level due to a shift in the position of the camera 20, as will be described later.

[0061] The water level determination unit 13 may determine the water level as described above after excluding the virtual water level gauge 200. If the excluded virtual water level gauge 200 is the reference virtual water level gauge 200, the water level determination unit 13 may newly determine the reference virtual water level gauge 200 from among the virtual water level gauges 200 that have not been excluded.

[0062] The exclusion of the virtual water level gauge 200 by the water level determination unit 13 will be described with reference to the flowchart of FIG. 15. The water level determination unit 13 performs the following process for each virtual water level gauge 200. The water level determination unit 13 calculates a relative error, which is a difference value between the values ​​related to the water level and other virtual water level gauges 200 based on the detection result by the detection unit 12 (S401). The calculation of the relative error between the virtual water level gauges 200 may be performed before the processing for each virtual water level gauge 200. Next, the water level determination unit 13 compares the number of relative errors that are abnormal values ​​(i.e., relative errors whose absolute values ​​are equal to or greater than the threshold value X for determining abnormal values) with the threshold value Y for determining the exclusion of the virtual water level gauge 200 (S402). If it is determined as a result of the comparison that the number of relative errors that are abnormal values ​​is less than the threshold value Y (YES in S402), the water level determination unit 13 sets the virtual water level gauge 200 as the virtual water level gauge 200 to be used for determining the water level (S403). That is, in this case, the water level determination unit 13 includes the virtual water level gauge 200 in the calculations for determining the water level thereafter. If the comparison results in a determination that the number of relative errors that are abnormal values ​​is equal to or greater than the threshold Y (NO in S402), the water level determination unit 13 excludes the virtual water level gauge 200 from the virtual water level gauges 200 used to determine the water level (S404). That is, in this case, the water level determination unit 13 excludes the virtual water level gauge 200 from the calculations for determining the water level thereafter.

[0063] Next, the water level determination unit 13 determines whether the value used to determine the calculated water level has not changed over the entire period going back a preset period Tc from the current time point and is a minimum value (e.g., 0) or a maximum value (e.g., 100) (S405). If it is determined that the value is not any of these (NO in S405), the water level determination unit 13 leaves the virtual water level gauge 200 as the virtual water level gauge 200 used to determine the water level. If it is determined that the value is any of these (YES in S405), the water level determination unit 13 excludes the virtual water level gauge 200 from the virtual water level gauges 200 used to determine the water level (S406).

[0064] The position of the camera 20 may be significantly shifted due to environmental factors such as wind and rain, or factors such as a collision with some object. As a result, for example, as in the image 100 shown in Figs. 16 and 18, the position of the water part 300 of a river or the like reflected in the image 100 is significantly shifted from the position of the virtual water level gauge 200 in the image 100. For example, in the image 100 shown in Fig. 16, the position of the water surface is significantly shifted between the virtual water level gauges 200. Also, in the image 100 shown in Fig. 18, many of the virtual water level gauges 200 no longer include the part 310 showing water. In this state, the water level cannot be appropriately determined from the virtual water level gauge 200. In this case, it is necessary to re-install the camera 20, and it is important to detect the occurrence of this event.

[0065] Therefore, the water level determination unit 13 may determine whether or not the water level can be determined based on the determination result of whether or not each of the multiple water level determination regions is to be used for determining the water level. The water level determination unit 13 may compare the number of water level determination regions determined not to be used for determining the water level with a preset threshold value, and determine whether or not the water level can be determined based on the comparison result.

[0066] For example, the water level determination unit 13 determines whether or not the water level can be determined as follows. The water level determination unit 13 determines whether each virtual water level gauge 200 is excluded from the water level determination as described above. The water level determination unit 13 counts the number of virtual water level gauges 200 determined to be excluded from the water level determination. The water level determination unit 13 compares the counted number with a preset threshold value (for example, 3 when five virtual water level gauges 200 are used). If the counted number is equal to or greater than the threshold value, the water level determination unit 13 determines that there is an abnormality in the installation of the camera 20 and that the water level cannot be determined. In this case, the water level determination unit 13 does not perform subsequent water level determinations, or, even if it does perform a water level determination, it sets the value to an unreliable value. If the counted number is less than the threshold value, the water level determination unit 13 determines that the water level can be determined. In this case, the water level determination unit 13 performs subsequent water level determinations as described above.

[0067] An example of determining whether or not the water level can be determined is shown below when excluding the virtual water level gauges 200 from the water level determination using the relative error between the virtual water level gauges 200 described above. FIG. 17 shows a table of an example of the relative error calculated when there are five virtual water level gauges 200 A to E corresponding to the image shown in FIG. 16. In the example shown in FIG. 17, all the virtual water level gauges 200 are excluded from the virtual water level gauges 200 used in determining the water level. In this case, it is determined that the number of virtual water level gauges 200 excluded from the water level determination is equal to or greater than a threshold value, and it is determined that the water level determination is not possible. Note that the example shown in FIG. 17 uses the relative error between the virtual water level gauges 200, but it may be based on the detection of the portion 400 in which the obstacle is captured as described above.

[0068] An example of determining whether or not the water level can be determined is shown when determining whether or not the virtual water level gauge 200 is excluded from the water level determination using the time series values ​​used to determine the water level of each of the virtual water level gauges 200 described above. FIG. 19 shows a table of an example of the relative error calculated when there are five virtual water level gauges 200 A to E corresponding to the image shown in FIG. 18. In the example shown in FIG. 18 and FIG. 19, the four virtual water level gauges 200 B to E do not capture the water surface. Therefore, the values ​​used to determine the water level of these virtual water level gauges 200 do not change over the entire period described above and are the minimum values. Therefore, the four virtual water level gauges 200 B to E are excluded from the virtual water level gauges 200 used to determine the water level. In this case, it is determined that the number of virtual water level gauges 200 excluded from the water level determination is equal to or greater than a threshold value, and it is determined that the water level determination is not possible.

[0069] 18, many of the virtual water level gauges 200 no longer include the portion 310 showing water, but a similar determination is made in a case where many of the virtual water level gauges 200 only include the portion 310 showing water because the camera 20 is facing the center of the river, etc. In this case, the value used to determine the water level does not change over the entire period described above and is the maximum value, so the virtual water level gauge 200 is excluded from the virtual water level gauges 200 used to determine the water level.

[0070] The judgment by the water level judgment unit 13 as to whether or not the water level judgment can be performed will be explained using the flowchart in FIG. 20. At the time of the judgment, it is judged whether or not each virtual water level gauge 200 is excluded from the water level judgment. The water level judgment unit 13 compares the number of virtual water level gauges 200 excluded from the water level judgment with a threshold value Z for judging whether or not the water level judgment can be performed (S501). If it is judged as a result of the comparison that the number of virtual water level gauges 200 excluded from the water level judgment is less than the threshold value Z (YES in S501), the water level judgment unit 13 judges that the camera 20 is installed normally and the water level can be judged (S502). If it is judged as a result of the comparison that the number of virtual water level gauges 200 excluded from the water level judgment is equal to or greater than the threshold value Z (NO in S501), the water level judgment unit 13 judges that the camera 20 is not installed normally and the water level cannot be judged (S503).

[0071] The water level determination unit 13 outputs information indicating the water level, which is the determination result. For example, the water level determination unit 13 transmits or outputs the information to a device or module in which the determined water level is used. The water level determination unit 13 may also display the determination result or transmit it to a terminal used by the user of the water level determination system 10 so that the user can refer to the water level, which is the determination result. The water level determination unit 13 may also output to a method and destination other than those described above. The above are the functions of the water level determination system 10 according to this embodiment.

[0072] Next, the process executed by the water level determination system 10 according to this embodiment (the operating method performed by the water level determination system 10) will be described using the flowchart in Fig. 21. In this process, the image acquisition unit 11 acquires an image 100 obtained by capturing an image of a location to be determined for the water level by the camera 20 (S01). Next, the detection unit 12 detects a portion 310 in which water is reflected in each of a plurality of virtual water level gauges 200 set at different positions in the image 100 (S02). In addition, a portion 400 in which an obstacle is reflected in the virtual water level gauge 200 may be detected.

[0073] Next, the water level determination unit 13 determines whether or not each virtual water level gauge 200 is to be used for determining the water level based on the detection result by the detection unit 12, and the detection result of the virtual water level gauge 200 determined to be used for determining the water level is used to determine the water level (S03). Also, it may be determined whether or not the water level can be determined based on the determination result of whether or not each virtual water level gauge 200 is to be used for determining the water level. Next, the water level determination unit 13 outputs the water level determination result (S04). The above water level determination process (S01 to S04) is repeated every time an image 100 is acquired (S01). The above is the process executed by the water level determination system 10 according to this embodiment.

[0074] In the above-described embodiment, when determining the water level, it is determined whether or not each of the multiple virtual water level gauges 200 is to be used in determining the water level. As a result, only the detection results of the virtual water level gauges 200 suitable for determining the water level are used to determine the water level. Therefore, according to this embodiment, the water level can be determined with high accuracy.

[0075] Also, as in the above-described embodiment, the decision as to whether or not to use the virtual water level gauge 200 for determining the water level may be made based on statistics such as the variance or standard deviation of the values ​​related to the water levels of a plurality of virtual water level gauges 200. With this configuration, the above-described decision can be made reliably and appropriately based on the statistics. As a result, the water level can be determined reliably, appropriately, and with high accuracy.

[0076] Also, as in the above-mentioned embodiment, the decision as to whether or not to use the virtual water level gauge 200 for judging the water level may be made based on the detection result of the part 400 in which an obstacle is shown in the virtual water level gauge 200. With this configuration, the above-mentioned decision can be made reliably and appropriately when the object that may become an obstacle is known in advance. As a result, the water level can be judged reliably, appropriately and with high accuracy.

[0077] As in the above-described embodiment, the decision as to whether or not to use the virtual water level gauge 200 for judging the water level and the judgment of the water level after the decision may be performed using a pre-stored reference difference value, more specifically, the reference virtual water level gauge 200 and a correction value. With this configuration, for example, even if there is a deviation in the installation relative to the water level between the virtual water level gauges 200 as described above, the water level can be judged with high accuracy.

[0078] As in the above-described embodiment, the decision as to whether or not to use the virtual water level gauge 200 for determining the water level may be made based on the difference value between the values ​​relating to the water level among the multiple virtual water level gauges 200. With this configuration, the above decision can be made reliably and appropriately based on the difference value. As a result, the water level can be determined reliably, appropriately, and with high accuracy.

[0079] The determination of whether or not to use the virtual water level gauge 200 to determine the water level may be performed by any combination of the above methods. Also, the determination of whether or not to use the virtual water level gauge 200 to determine the water level does not have to be performed as described above, and may be performed based on the detection result by the detection unit 12.

[0080] Also, as in the above-described embodiment, it may be determined whether or not the water level can be determined based on the result of determining whether or not the virtual water level gauge 200 is to be used for determining the water level. This configuration makes it possible to prevent the water level from being continued even though the water level cannot be determined appropriately. The above determination may be made based on the result of comparing the number of virtual water level gauges 200 that are not to be used for determining the water level with a threshold value. This configuration makes it possible to make the above determination more appropriately. However, the above determination may be made by a method other than the above.

[0081] Also, as in the above-described embodiment, a value used to determine the water level may be calculated using the detection results for each divided area 210 obtained by dividing the virtual water level meter 200 in the water level direction. This configuration allows the water level to be determined with even greater accuracy. In this case, specifically, as described above, each divided area 210 may be determined to be an area related to water, non-water, or indefinite, and the water level may be determined based on the determination results and the positional relationship of the divided areas. However, as long as the detection results for each divided area 210 are used to calculate the value used to determine the water level, the value may be calculated by a method other than the above.

[0082] The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically combined, or may be realized by using two or more devices that are physically or logically separated and directly or indirectly connected (for example, by wire, wirelessly, etc.). The functional blocks may be realized by combining the one device or the multiple devices with software.

[0083] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, mapping, assignment, etc. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. In either case, as described above, there is no particular limitation on the method of realization.

[0084] For example, the water level determination system 10 according to an embodiment of the present disclosure may function as a computer that performs the information processing of the present disclosure. Fig. 22 is a diagram showing an example of a hardware configuration of the water level determination system 10 according to an embodiment of the present disclosure. The above-mentioned water level determination system 10 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0085] In the following description, the term "apparatus" can be read as a circuit, a device, a unit, etc. The hardware configuration of the water level determination system 10 may be configured to include one or more of the devices shown in the figure, or may be configured to exclude some of the devices.

[0086] Each function in the water level determination system 10 is realized by loading a specific software (program) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via a communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and the storage 1003.

[0087] The processor 1001, for example, operates an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, each function in the water level determination system 10 described above may be realized by the processor 1001.

[0088] Moreover, the processor 1001 reads out a program (program code), a software module, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to the read out programs. As the program, a program that causes a computer to execute at least a part of the operations described in the above-mentioned embodiment is used. For example, each function in the water level determination system 10 may be realized by a control program stored in the memory 1002 and operated in the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via an electric communication line.

[0089] The memory 1002 is a computer-readable recording medium, and may be composed of at least one of, for example, a read only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store a program (program code), software modules, etc. that are executable to perform information processing according to an embodiment of the present disclosure.

[0090] The storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (for example, a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (for example, a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, and the like. The storage 1003 may be called an auxiliary storage device. The storage medium provided in the water level determination system 10 may be, for example, a database including at least one of the memory 1002 and the storage 1003, a server, or other appropriate medium.

[0091] The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0092] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0093] In addition, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0094] The water level determination system 10 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc., and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0095] The order of the steps, sequences, flow charts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0096] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0097] The determination may be based on a value represented by a single bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0098] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

[0099] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0100] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0101] Additionally, software, instructions, information, etc. may be transmitted or received over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired and / or wireless technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave, etc.), then these wired and / or wireless technologies are included within the definition of transmission media.

[0102] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0103] Furthermore, the information, parameters, etc. described in this disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information.

[0104] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), and the like. In addition, "judgment" and "decision" can include considering resolving, selecting, choosing, establishing, comparing, etc., to be a "judgment" or "decision." In other words, "judgment" and "decision" can include considering some action to be a "judgment" or "decision." In addition, "judgment" can be interpreted as "assuming," "expecting," "considering," etc.

[0105] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0106] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0107] Any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0108] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0109] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0110] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different." [Explanation of symbols]

[0111] 10...water level determination system, 11...image acquisition unit, 12...detection unit, 13...water level determination unit, 20...camera, 1001...processor, 1002...memory, 1003...storage, 1004...communication device, 1005...input device, 1006...output device, 1007...bus.

Claims

1. an image acquisition unit that acquires an image obtained by imaging a location that is to be subjected to water level determination; a detection unit that detects a portion in which water is reflected in each of a plurality of water level determination regions that are set at different positions in the image acquired by the image acquisition unit; a water level determination unit that determines whether or not each of the plurality of water level determination regions is to be used for determining the water level based on a detection result by the detection unit, and determines the water level using the detection result of the water level determination region that is determined to be used for determining the water level; Equipped with The water level determination unit stores a reference difference value of values ​​related to the water level between the multiple water level determination regions, and determines the water level using the reference difference value.

2. an image acquisition unit that acquires an image obtained by imaging a location that is to be subjected to water level determination; a detection unit that detects a portion in which water is reflected in each of a plurality of water level determination regions that are set at different positions in the image acquired by the image acquisition unit; a water level determination unit that determines whether or not each of the plurality of water level determination regions is to be used for determining the water level based on a detection result by the detection unit, and determines the water level using the detection result of the water level determination region that is determined to be used for determining the water level; Equipped with The water level determination unit calculates a difference value of the water level between each of the multiple water level determination areas based on the detection results by the detection unit, and determines whether or not to use each of the multiple water level determination areas for water level determination based on the calculated difference value.

3. an image acquisition unit that acquires an image obtained by imaging a location that is to be subjected to water level determination; a detection unit that detects a portion in which water is reflected in each of a plurality of water level determination regions that are set at different positions in the image acquired by the image acquisition unit; a water level determination unit that determines whether or not each of the plurality of water level determination regions is to be used for determining the water level based on a detection result by the detection unit, and determines the water level using the detection result of the water level determination region that is determined to be used for determining the water level; Equipped with the water level determination unit determines whether or not it is possible to determine the water level based on a determination result as to whether or not each of the plurality of water level determination regions is to be used for determining the water level; The water level determination unit compares the number of areas for water level determination that are determined not to be used for water level determination with a preset threshold value, and determines whether or not it is possible to determine the water level based on the comparison result.

4. The water level determination system according to any one of claims 1 to 3, wherein the water level determination unit calculates statistics of values ​​related to the water level in each of the plurality of water level determination areas based on the detection results by the detection unit, and determines whether or not to use the calculated statistics for each of the plurality of water level determination areas for determining the water level.

5. A water level determination system as described in any one of claims 1 to 4, wherein the detection unit detects obstacles in each of the plurality of water level determination areas to be used by the water level determination unit to determine whether or not to use each of the plurality of water level determination areas for determining the water level.

6. The water level determination system according to any one of claims 1 to 5, wherein the detection unit detects an area in which water is reflected for each divided area obtained by dividing the area for water level determination in the direction of the water level.

7. The water level determination system of claim 6, wherein the water level determination unit determines each divided area as being related to water, non-water, or indefinite depending on the detection result of the detection unit, and determines the water level based on the determination result and the positional relationship of the divided areas.

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