Release amount estimation device, release amount estimation method, and program

Abstract

A release amount estimation device is provided with: a detection unit that detects a leaked jet of gas on the basis of an inspection image in which an object to be inspected is captured; an outlet diameter measuring unit that measures, on the basis of the inspection image, an outlet diameter indicating the size of a jet outlet of the inspection target; a velocity calculation unit that calculates the flow velocity of the jet flow in a constant velocity nuclear region on the basis of the inspection image; a volume calculation unit that calculates the volume of the jet flow on the basis of the outlet diameter and the flow rate of the jet flow; a concentration estimation unit that estimates a leaked gas concentration indicating the concentration of the leaked gas on the basis of a gas concentration-brightness table in which the relationship between the concentration of the gas and the brightness value of the image in which the gas has been captured, and the brightness value of the constant-velocity nuclear region in the inspection image; and a release amount estimation unit that estimates the amount of release of the gas on the basis of the volume of the jet flow and the concentration of the leaked gas.

Description

Technical Field

[0001] The invention relates to a release amount estimation device, a release amount estimation method and a program.

[0002] This application claims priority based on patent application No. 2022-136926 filed in Japan on August 30, 2022, and the contents are incorporated herein by reference. Background Art

[0003] As a technology for detecting gas leakage, there is the following method: a gas detection unit such as an infrared camera or a laser absorption spectrometer that can detect gas absorption wavelengths (hereinafter also referred to as "specific wavelengths") is mounted on an unmanned aerial vehicle, and gas leaks in gas piping are inspected from above (for example, refer to Patent Document 1).

[0004] In the case of gas leakage, a specific wavelength is absorbed at the leakage site, so, for example, when the gas detection unit is a camera, a black shadow representing the leaked gas will appear in the captured image. The absorption of the specific wavelength changes due to the gas concentration, so the black shadow has a shade corresponding to the gas concentration. Therefore, by detecting the black shadow and analyzing its shade, it is possible to detect gas leakage and measure the gas concentration.

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6703756 Summary of the invention

[0008] Technical issues to be solved by the invention

[0009] However, in the conventional technology, since the visualization is based on absorption at a specific wavelength, it is difficult to distinguish whether the gas concentration is locally high or the gas exists in a large area (thickness) in the height direction, especially for a location that absorbs more at a specific wavelength and appears black on the image. Therefore, it may not be possible to accurately estimate the amount of gas released from a gas leak such as a gas pipe.

[0010] An object of the present invention is to provide a release amount estimation device, a release amount estimation method, and a program capable of estimating the release amount of gas from an inspection object with high accuracy.

[0011] Means for solving technical problems

[0012] According to one embodiment of the present invention, a release amount estimation device for estimating the release amount of gas leaked from an inspection object comprises: a detection unit, which detects a jet of the gas leaked from the inspection object based on an inspection image captured by the inspection object; an outlet diameter measurement unit, which measures an outlet diameter representing the size of an outlet of the jet of the inspection object based on the inspection image; a velocity calculation unit, which calculates the flow velocity of a constant velocity core region of the jet based on the inspection image; a volume calculation unit, which calculates the volume of the jet based on the outlet diameter and the flow velocity of the jet; a concentration estimation unit, which estimates a leakage gas concentration representing the concentration of the leaked gas based on a brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table that determines the relationship between the concentration of the gas and the brightness value of the image captured by the gas; and a release amount estimation unit, which estimates the release amount of the gas based on the volume of the jet and the leakage gas concentration.

[0013] According to one embodiment of the present invention, a release amount estimation method for estimating the release amount of gas leaked from an inspection object includes the following steps: detecting a jet of the gas leaked from the inspection object based on an inspection image captured of the inspection object; measuring an outlet diameter representing the size of a jet outlet of the inspection object based on the inspection image; calculating a flow velocity of a constant velocity core region of the jet based on the inspection image; calculating the volume of the jet based on the outlet diameter and the flow velocity of the jet; estimating a leakage gas concentration representing the concentration of the leaked gas based on a brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table that determines a relationship between the concentration of the gas and the brightness value of an image captured of the gas; and estimating the release amount of the gas based on the volume of the jet and the leakage gas concentration.

[0014] According to one embodiment of the present invention, a program causes a release amount estimation device for estimating the release amount of gas leaked from an inspection object to perform the following steps: detecting a jet of the gas leaked from the inspection object based on an inspection image captured of the inspection object; measuring an outlet diameter representing the size of a jet outlet of the inspection object based on the inspection image; calculating a flow velocity of a constant velocity core region of the jet based on the inspection image; calculating a volume of the jet based on the outlet diameter and the flow velocity of the jet; estimating a leakage gas concentration representing the concentration of the leaked gas based on a brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table that determines a relationship between the concentration of the gas and the brightness value of an image captured of the gas; and estimating the release amount of the gas based on the volume of the jet and the leakage gas concentration.

[0015] Effects of the Invention

[0016] According to the above aspect, the amount of gas released from the inspection object can be estimated with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram showing the overall configuration of a monitoring system according to one embodiment.

[0018] Figure 2 It is a block diagram showing the functional structure of a release amount estimation device according to one embodiment.

[0019] Figure 3 This is a diagram showing an example of an inspection image according to an embodiment.

[0020] Figure 4 This is the first figure for explaining the characteristics of the jet flow.

[0021] Figure 5 FIG. 2 is a second diagram for explaining the characteristics of the jet flow.

[0022] Figure 6 This is a flowchart showing an example of processing of the release amount estimation device according to one embodiment.

[0023] Figure 7 This is a diagram showing an example of a gas concentration-brightness table according to one embodiment.

[0024] Figure 8 This is a diagram showing an example of a gas concentration test facility according to an embodiment. DETAILED DESCRIPTION

[0025] (Overall structure of the release amount estimation device)

[0026] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram showing the overall configuration of a monitoring system according to one embodiment.

[0028] When the monitoring system 1 detects leakage of gas G from the gas pipe 9, the release amount of the leaked gas G is estimated. The gas pipe 9 is provided at a gas utilization site, etc., and is a pipe for circulating gas G inside. The gas pipe 9 is an example of an inspection object of the release amount estimation device 10 involved in this embodiment. In other embodiments, for example, a storage tank of gas G may be set as an inspection object.

[0029] like Figure 1 As shown, the monitoring system 1 includes a release amount estimation device 10 , a moving object 20 , and a camera 30 .

[0030] The mobile body 20 is, for example, an unmanned aircraft (drone) or the like (eg, an unmanned aerial vehicle, etc.), and moves within the installation area of ​​the gas pipe 9 according to a preset monitoring route or according to an operation instruction of an operator.

[0031] The camera 30 is mounted on the mobile body 20 and photographs the gas pipe 9. The camera 30 is, for example, an infrared camera that can detect the gas absorption wavelength (specific wavelength) of the gas G. Furthermore, the camera 30 changes the orientation (photographing direction) of the photographing range R according to the positional relationship between the mobile body 20 and the gas pipe 9, thereby being able to photograph various parts of the gas pipe 9, such as the upper surface and the side surface.

[0032] When the movable body 20 moves in the installation area, the camera 30 continuously captures the gas pipe 9. The movable body 20 sequentially transmits the image of the gas pipe 9 captured by the camera 30 (hereinafter also referred to as an inspection image) to the release amount estimation device 10.

[0033] The release amount estimation device 10 is communicatively connected to the mobile body 20. When leakage of the gas G from the gas pipe 9 is detected based on the inspection image of the gas pipe 9 acquired from the mobile body 20, the release amount estimation device 10 estimates the release amount of the leaked gas G.

[0034] in addition, Figure 1 2 shows an example in which the emission amount estimation device 10 is installed at a monitoring base point away from the installation area of ​​the gas pipe 9 , but the present invention is not limited to this. In another embodiment, the emission amount estimation device 10 may be built in the mobile body 20 .

[0035] (Functional Structure of Release Amount Estimation Device)

[0036] Figure 2 It is a block diagram showing the functional structure of a release amount estimation device according to one embodiment.

[0037] like Figure 2 As shown, the release amount estimation device 10 includes a processor 11, a memory 12, a storage device 13 and a communication interface 1.4.

[0038] The processor 11 operates according to a predetermined program, thereby fulfilling the functions of a detection unit 110 , an outlet diameter measurement unit 111 , a velocity calculation unit 112 , a volume calculation unit 113 , a concentration estimation unit 114 , and a release amount estimation unit 115 .

[0039] The detection unit 110 acquires the inspection image obtained by the camera 30 through the movable body 20. The detection unit 110 detects the jet F of the gas G leaking from the gas pipe 9 based on the acquired inspection image.

[0040] The outlet diameter measuring unit 111 measures the outlet diameter indicating the size of the jet outlet 91 of the gas pipe 9 based on the inspection image.

[0041] The velocity calculation unit 112 calculates the flow velocity of the jet flow F based on the inspection image.

[0042] The volume calculation unit 113 calculates the volume of the jet flow F based on the outlet diameter of the jet flow outlet 91 and the flow velocity of the jet flow.

[0043] The concentration estimating unit 114 estimates the concentration of the gas G leaking from the gas pipe 9 (the leakage gas concentration) based on the inspection image. Specifically, the concentration estimating unit 114 estimates the concentration of the gas G in the constant velocity core region of the jet F in the inspection image based on the flow velocity of the jet F. Furthermore, the concentration estimating unit 114 estimates the leakage gas concentration based on a table defining the relationship between the concentration of the gas G and the brightness value of the image in which the gas G is captured and the brightness value of the constant velocity core region of the inspection image.

[0044] The release amount estimation unit 115 estimates the release amount of the gas G based on the volume of the jet flow F and the leaked gas concentration estimated by the concentration estimation unit 114 .

[0045] The memory 12 has a memory area necessary for the operation of the processor 11 .

[0046] The storage device 13 is a so-called auxiliary storage apparatus, and may be, for example, a HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like.

[0047] The communication interface 14 is an interface for transmitting and receiving various information with an external device (moving object 20 ).

[0048] In addition, the prescribed program executed by the processor 11 of the release amount estimation device 10 is stored in a computer-readable recording medium. And, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory, etc. And, the computer program can be transmitted to the computer through a communication line, and the computer receiving the transmission executes the program. Moreover, the program can also be used to implement a part of the above-mentioned functions. Furthermore, it can be a so-called differential file (differential program) that can be implemented by combining with a program that records all the above-mentioned functions in a computer system.

[0049] (About the characteristics of the jet)

[0050] Figure 3 This is a diagram showing an example of an inspection image according to an embodiment.

[0051] For example, Figure 1As shown in FIG. 1 , it is assumed that the gas G leaks from the side surface of the gas pipe 9 . Figure 3 The inspection image shown is a photograph of the leakage site (jet outlet 91) of the gas G and the jet flow F taken from above (from the position of the moving body 20 indicated by the solid line).

[0052] In this embodiment, the camera 30 is an infrared camera capable of detecting a specific wavelength of the gas G. If the gas pipe 9 including the leakage portion of the gas G is photographed, Figure 3 As shown, an inspection image is obtained in which the jet F of gas G appears as a black shadow. If the radiation conditions are the same as the background, the higher the concentration of gas G or the thicker the gas G, the darker the black shadow of the inspection image becomes. However, as described above, when only the shade of the black shadow is analyzed, it is difficult to distinguish whether the concentration of gas G is high or the thickness of gas G is large, so it may not be possible to accurately estimate the release amount of gas G. Therefore, the release amount estimation device 10 involved in this embodiment estimates the release amount of gas G using the characteristics of the jet F described below.

[0053] Figure 4 This is the first figure for explaining the characteristics of the jet flow.

[0054] Figure 5 FIG. 2 is a second diagram for explaining the characteristics of the jet flow.

[0055] like Figure 4 As shown, the jet F above a certain arbitrary flow velocity has a triangular region that maintains the motion of the constant velocity core P1. In the region including the constant velocity core P1 of the jet F (hereinafter also recorded as the constant velocity core region P2), it is not easily affected by external interference. In addition, the expansion characteristics of the constant velocity core region P2 and the flow outside it without external interference have been standardized.

[0056] In the fully developed area P3, which is further downstream than the constant velocity core area P2, although the maximum velocity um of the jet F decreases uniformly, the decrease in the maximum velocity um is a function of the outlet conditions (exit velocity U0, arrival distance x, outlet diameter b0), and the decrease in the velocity u (velocity distribution) around it is given by Figure 5 It can be described by the Gaussian distribution shown. Figure 5 The vertical axis represents the value of normalizing the flow velocity u to the maximum flow velocity um, and the horizontal axis represents λ = y / x. Therefore, if the conditions are ideal, the expansion of the jet F in the constant velocity core region P2 and the fully developed region P3 in the width direction Dw (the expansion of the edge of the velocity distribution) can also be uniquely determined under the outlet conditions.

[0057] On the surface, the jet F fluctuates due to external disturbances, and its shape changes unstably. If the fluctuating part is regarded as an area that actively exchanges motion with the outside outside the constant velocity core area P2, it is considered that the outlet condition of the jet F is less affected by the external disturbance. Therefore, by using the volume flow rate and concentration of the gas G obtained from the outlet condition, the gas leakage flow rate can be calculated with higher accuracy than the prior art. Therefore, the release amount estimation device 10 involved in this embodiment obtains the outlet condition of the jet F from the inspection image, and estimates the concentration and release amount of the leaked gas G based on the outlet condition.

[0058] (Processing flow of the release amount estimation device)

[0059] Figure 6 This is a flowchart showing an example of processing of the release amount estimation device according to one embodiment.

[0060] Below, reference Figure 6 , the processing flow of estimating the concentration and release amount of the leaked gas G by the release amount estimation device 10 is described.

[0061] First, the detection unit 110 obtains an inspection image ( Figure 3 ) to detect the jet F of the gas G leaking from the gas pipe 9 (step S1). A technique for detecting the leakage (jet F) of the gas G from the inspection image is known, so detailed description is omitted.

[0062] Next, the outlet diameter measuring unit 111 measures the outlet diameter of the jet outlet 91 as one of the outlet conditions based on the inspection image (step S2). Figure 4 As shown, the shape of the jet outlet 91 is assumed to be circular, and the outlet diameter is set to the radius b0 of the jet outlet 91.

[0063] Next, the velocity calculation unit 112 calculates the flow velocity (exit flow velocity) of the jet F as one of the exit conditions (step S3). The flow velocity of the gas G in the jet outlet 91 is consistent with the flow velocity in the constant velocity core P1. Furthermore, at the outer edge of the jet F in the constant velocity core region P2, the flow velocity of the gas G is ideally as follows: Figure 5 The Gaussian distribution shown in the example. If it becomes more downstream than the constant velocity core area P2, the outer edge portion is more turbulent due to the movement exchange of the gas G, but if it is near the jet outlet 91, the flow velocity of the gas G at the outer edge portion should be close to the Gaussian distribution. Therefore, the velocity calculation unit 112 estimates the flow velocity in the constant velocity core from the flow velocity of the outer edge portion near the jet outlet 91 of the inspection image, and estimates the flow velocity near the jet outlet 91. In addition, the reason for calculating the flow velocity of the outer edge portion of the jet F is as follows: compared with the central portion of the jet F, it is easy to grasp the shape and brightness characteristics of the jet F through the concentration difference with the surrounding fluid, so the velocity can be calculated more accurately.

[0064] The velocity calculation unit 112 calculates the velocity of the outer edge of the jet F near the jet outlet 91 using a flow velocity measurement technique such as optical flow. For example, the velocity calculation unit 112 extracts a feature point p (pixel) of the outer edge of the jet F on the jet outlet 91 side (upstream side of the ejection direction Df) from an arbitrary inspection image (first inspection image). For example, the feature point p is a point (so-called corner) at which the cumulative value of the difference between the center of the region and the brightness within the pixel region is greater than a threshold when an arbitrary pixel region is set. In the constant velocity core region P2, it is not easily affected by external disturbances, and the diffusion amount in its outer edge (end in the width direction Dw) is small. Therefore, when the feature point p extracted from the vicinity of the jet outlet 91 moves to the position of the feature point p' after n frames (n is an arbitrary value), it can also be assumed that the shape and brightness are maintained. Based on this assumption, the velocity calculation unit 112 extracts a pixel having the same brightness value as the feature point p from the inspection image (second inspection image) after n frames as the moving destination of the feature point p (feature point p'). The velocity calculation unit 112 calculates the flow velocity u of the outer edge of the constant velocity core region P2 of the jet F from the difference between the pixel coordinates of the characteristic points p and p' in two time-series continuous inspection images. The characteristic points p and p' may be a region consisting of a plurality of pixels representing a characteristic shape of the outer edge of the jet F.

[0065] In other embodiments, for example, a laser irradiation device may be mounted on the movable body 20 and the flow velocity of the jet flow F may be calculated using the PIV (Particle Image Velocimetry) technology.

[0066] Next, the volume calculation unit 113 calculates the volume V of the jet flow F from the area A of the jet flow outlet 91 based on the radius b0 and the flow velocity of the jet flow F (step S4). For example, the volume V of the jet flow F is obtained by using the prediction formula (1) of the maximum flow velocity um at the arrival position x of the jet flow F and the prediction formula (2) of the flow velocity u in the width direction Dw relative to the maximum flow velocity um, and by using the formula (3).

[0067] [Formula 1]

[0068]

[0069] [Formula 2]

[0070]

[0071] [Formula 3]

[0072]

[0073] Next, the concentration estimation unit 114 uses a gas concentration-brightness table T ( Figure 7 ), estimate the leakage gas concentration (density) from the inspection image (step S5).

[0074] Figure 7 This is a diagram showing an example of a gas concentration-brightness table according to one embodiment.

[0075] Figure 7 The vertical axis represents gas concentration (volume molar concentration, mass molar concentration or mass % concentration), and the horizontal axis represents brightness value. In addition, the gas concentration-brightness table T has different tables T1, T2, T3, T4, ... for each gas thickness.

[0076] Figure 8 This is a diagram showing an example of a gas concentration test facility according to an embodiment.

[0077] Gas concentration-brightness table T is used in advance Figure 8 The test device 8 is manufactured by using the test device 8 shown in FIG. The test device 8 includes a test tube 80, a black body furnace 81, a concentration meter 82, and a camera 83. The camera 83 is the same camera as the camera 30, and is an infrared camera capable of detecting a specific wavelength of the gas G in this embodiment.

[0078] The test tube 80 is a transparent test tube, and the gas G in which the gas concentration in the premixed state is changed is placed inside. The test tube 80 is provided with an air intake port and an air exhaust port for the gas G, and the gas G can be taken in and exhausted while checking the concentration meter 82, and the gas concentration in the test tube 80 can be changed. The camera 83 outputs the image of the gas G in the test tube 80 and the black body furnace 81 to the emission amount estimation device 10 every time the gas concentration is changed.

[0079] The concentration estimation unit 114 of the emission estimation device 10 measures the brightness value of the area where the black body furnace 81 is reflected from the image captured by the camera 83 for each gas concentration. The brightness value is a brightness value corresponding to the gas concentration of the gas G. The concentration estimation unit 114 associates the gas concentration and the brightness value measured from the image, creates a gas concentration-brightness table T, and records it in the storage device 13.

[0080] Furthermore, the concentration estimation unit 114 creates gas concentration-brightness tables T1, T2, T3, T4, ... according to the thickness of the gas, based on the image captured by changing the length L of the test tube 80 (i.e., the thickness of the gas G). Figure 7 ). Thus, the gas concentration corresponding to the thickness of the gas G corresponding to the radius b0 of the jet outlet 91 can be estimated.

[0081] When it is assumed that the gas G is in a premixed state before becoming the jet F, it is considered that the premixed state is maintained in the constant velocity core P1. Therefore, in step S5, the concentration estimation unit 114 first measures the brightness value of the constant velocity core region P2 of the jet F in the inspection image. At this time, the concentration estimation unit 114 calculates the average value of the brightness values ​​of the pixels in the prescribed range on the central part of the width direction Dw of the constant velocity core region P2 and close to the jet outlet 91 as the brightness value of the constant velocity core region P2 in the inspection image. In addition, the size of the prescribed range can be changed according to the flow velocity of the jet F calculated in step S3.

[0082] Furthermore, the concentration estimating unit 114 estimates the thickness of the gas G based on the radius b0 of the jet outlet 91 measured in step S2, and reads the gas concentration-brightness table T corresponding to the estimated thickness of the gas G. Then, the concentration estimating unit 114 estimates the concentration of the gas G based on the brightness value of the constant velocity core region P2 measured from the inspection image and the gas concentration-brightness table T.

[0083] Next, the release amount estimation unit 115 multiplies the volume V of the jet flow F calculated in step S4 by the concentration of the gas G estimated in step S5 , and estimates the release amount (mass flow rate) of the gas G (step S6 ).

[0084] (Effect)

[0085] As described above, the release amount estimation device 10 involved in the present embodiment comprises: an outlet diameter measuring unit 111, which measures the outlet diameter (radius b0) of the jet outlet N 91 based on the inspection image taken of the gas piping 9; a velocity calculation unit 112, which calculates the flow velocity of the constant velocity core region P2 of the jet F based on the inspection image; a volume calculation unit 113, which calculates the volume V of the jet F based on the radius b0 and the flow velocity of the jet F; a concentration estimation unit 114, which estimates the leakage gas concentration based on the brightness value of the constant velocity core region P2 of the jet F in the inspection image and the gas concentration-brightness table T; and a release amount estimation unit 115, which estimates the release amount of the gas G based on the volume V of the jet F and the leakage gas concentration.

[0086] Thus, the release amount estimation device 10 can estimate the release amount of the gas G with high accuracy by using the characteristics of the jet flow F.

[0087] For example, the gas concentration-brightness table T obtained by the experiment represents the relationship between the gas concentration and the brightness value in the premixed state of the gas G. Therefore, when the brightness of the area with a large diffusion amount (for example, the fully developed area P3) in the black shadow of the mapped gas G is measured in the inspection image, the accurate leakage gas concentration cannot be measured. However, in the present embodiment, the concentration estimation unit 114 measures the brightness of the constant velocity core area P2 including the constant velocity core P1 while maintaining the premixed state, and compares it with the gas concentration-brightness table T, so that the leakage gas concentration can be estimated with good accuracy. In addition, the volume may change due to temperature, so by calculating the release amount (mass flow rate) of the gas G from the volume and the leakage gas concentration, the accurate leakage amount of the gas G can be measured.

[0088] Furthermore, the velocity calculation unit 112 can calculate the flow velocity of the jet flow F with high accuracy by calculating the flow velocity of the constant velocity core region P2 where the diffusion amount is smaller than that on the downstream side (the fully developed region P3 ).

[0089] The velocity calculation unit 112 calculates the flow velocity of the constant velocity core region P2 of the jet flow F based on the difference between the position of the characteristic point p of the outer edge of the jet flow F on the jet outlet 91 side in an arbitrary inspection image and the position of the characteristic point p′ in an inspection image after an arbitrary number of frames.

[0090] The velocity calculation unit 112 can more reliably obtain the flow velocity within the constant velocity core region P2 by calculating the flow velocity from the characteristic points p and p' on the jet outlet 91 side. Furthermore, the maximum flow velocity um of the jet F can be calculated from the flow velocity u at the outer edge of the jet F based on the velocity distribution.

[0091] Furthermore, the gas concentration-brightness table T has multiple different tables T1, T2, T3, T4, etc. according to the thickness of the gas G. The concentration estimation unit 114 estimates the thickness of the leaked gas G based on the radius b0 of the jet outlet 91, and estimates the leakage gas concentration based on the table corresponding to the estimated thickness of the gas G.

[0092] As described above, in the prior art, it is difficult to distinguish whether the gas concentration is high or the gas thickness is large from the brightness value of the image, and the gas concentration may not be accurately estimated. In contrast, in the present embodiment, the concentration estimation unit 114 estimates the thickness of the gas G from the radius b0 of the jet outlet 91 and uses a gas concentration-brightness table corresponding to the thickness of the gas G, thereby being able to accurately estimate the leakage gas concentration.

[0093] The concentration estimation unit 114 estimates the leaked gas concentration based on the average value of the brightness values ​​of the pixels in the predetermined range within the constant velocity core region P2. The concentration estimation unit 114 changes the size of the predetermined range based on the flow velocity of the jet F.

[0094] Thus, the concentration estimation unit 114 can appropriately measure the brightness of the region where the constant velocity core P1 is estimated to exist according to the flow velocity. As described above, the premixed state is maintained in the constant velocity core P1, so the leakage gas concentration can be estimated more accurately from the brightness of the constant velocity core P1 and the gas concentration-brightness table T.

[0095] In the above, one embodiment is described in detail with reference to the accompanying drawings, but the specific structure is not limited to the above description, and various design changes can be made. That is, in other embodiments, the order of the above processes can be appropriately changed. In addition, some processes can also be executed simultaneously.

[0096] The release amount estimation device 10 involved in the above-mentioned embodiment may be composed of a single computer, or the structure of the release amount estimation device 10 may be divided into a plurality of computers and configured, and the plurality of computers cooperate with each other to function as the release amount estimation device 10. In this case, a part of the computer constituting the release amount estimation device 10 may be mounted inside the mobile body 20, and another part of the computer may be set outside the mobile body 20.

[0097] Furthermore, in the above embodiment, the camera 30 is mounted on the moving body 20, but the present invention is not limited thereto. For example, in another embodiment, the camera 30 may be a fixed camera installed at a predetermined interval in the installation area of ​​the gas pipe 9.

[0098] Furthermore, in the above embodiment, the concentration estimation unit 114 of the emission estimation device 10 creates the gas concentration-brightness table T, but the present invention is not limited thereto. In another embodiment, the gas concentration-brightness table T may be created by another computer other than the emission estimation device 10.

[0099] Furthermore, in the above-mentioned embodiment, an example of preparing a plurality of gas concentration-brightness tables T according to the thickness of the gas G is described, but the invention is not limited thereto. In other embodiments, for example, the separation distance between the test tube 80 of the test device 8 and the camera 83 can be changed to further prepare a gas concentration-brightness table T for each separation distance. In this case, the concentration estimating unit 114 switches the table according to the separation distance between the camera 30 and the gas piping 9, thereby being able to estimate the gas concentration with higher accuracy.

[0100] <Notes>

[0101] The release amount estimation device, release amount estimation method, and program described in the above-mentioned embodiments can be understood, for example, as follows.

[0102] (1) According to the first method, a release amount estimation device 10 for estimating the release amount of gas G leaked from an inspection object 9 comprises: a detection unit 110 for detecting a jet F of gas G leaked from an inspection object 9 based on an inspection image captured by the inspection object 9; an outlet diameter measurement unit 111 for measuring an outlet diameter representing a size of a jet outlet 91 of the inspection object 9 based on the inspection image; a velocity calculation unit 112 for calculating a flow velocity of a constant velocity core region P2 of the jet F based on the inspection image; a volume calculation unit 113 for calculating a volume of the jet F based on the outlet diameter and the flow velocity of the jet F; a concentration estimation unit 114 for estimating a leakage gas concentration representing a concentration of the leaked gas G based on a brightness value of the constant velocity core region P2 in the inspection image and a gas concentration-brightness table T that determines a relationship between a concentration of the gas G and a brightness value of an image captured by the gas; and a release amount estimation unit 115 for estimating the release amount of the gas G based on the volume of the jet F and the leakage gas concentration.

[0103] Thus, the release amount estimation device 10 can estimate the release amount of the gas G with high accuracy by using the characteristics of the jet flow F.

[0104] For example, the gas concentration-brightness table T obtained by the experiment represents the relationship between the gas concentration and the brightness value in the premixed state of the gas G. Therefore, when the brightness of the area with a large diffusion amount (for example, the fully developed area P3) in the black shadow of the mapped gas G is measured in the inspection image, the accurate leakage gas concentration cannot be measured. However, in the present embodiment, the concentration estimation unit 114 measures the brightness of the constant velocity core area P2 including the constant velocity core P1 while maintaining the premixed state, and compares it with the gas concentration-brightness table T, so that the leakage gas concentration can be estimated with good accuracy. In addition, the volume may change due to temperature, so by calculating the release amount (mass flow rate) of the gas G from the volume and the leakage gas concentration, the accurate leakage amount of the gas G can be measured.

[0105] Furthermore, the velocity calculation unit 112 can calculate the flow velocity of the jet flow F with high accuracy by calculating the flow velocity of the constant velocity core region P2 where the diffusion amount is smaller than that on the downstream side (the fully developed region P3 ).

[0106] (2) According to the second method, in the release amount estimation device 10 involved in the first embodiment, the speed calculation unit 112 calculates the flow velocity of the constant velocity core area P2 of the jet F based on the difference between the position of the characteristic point p of the outer edge portion of the jet F on the jet outlet 91 side of the first inspection image among multiple inspection images and the position of the characteristic point p' in the inspection image that is an arbitrary number of frames later than the first inspection image, that is, the second inspection image.

[0107] The velocity calculation unit 112 can more reliably obtain the flow velocity within the constant velocity core region P2 by calculating the flow velocity from the characteristic points p and p' on the jet outlet 91 side. Furthermore, the maximum flow velocity um of the jet F can be calculated from the flow velocity u at the outer edge of the jet F based on the velocity distribution.

[0108] (3) According to the third method, in the release amount estimation device 10 involved in the first or second method, the gas concentration-brightness table T has multiple different tables according to the thickness of the gas G, and the concentration estimation unit 114 estimates the thickness of the leaked gas G based on the outlet diameter, and estimates the leakage gas concentration based on the estimated thickness of the gas G.

[0109] Thus, the concentration estimating unit 114 estimates the thickness of the gas G from the radius b0 of the jet outlet 91 and uses the gas concentration-brightness table corresponding to the thickness of the gas G, thereby being able to estimate the leakage gas concentration with high accuracy.

[0110] (4) According to the fourth embodiment, in the release amount estimation device 10 involved in any one of the first to third embodiments, the concentration estimation unit 114 estimates the leakage gas concentration based on the average value of the brightness values ​​of pixels in a specified range within the constant velocity core area P2, and changes the size of the specified range according to the flow rate of the jet F.

[0111] Thus, the concentration estimation unit 114 can appropriately measure the brightness of the region where the constant velocity core P1 is estimated to exist according to the flow velocity. Since the premixed state is maintained in the constant velocity core P1, the leakage gas concentration can be estimated more accurately from the brightness of the constant velocity core P1 and the gas concentration-brightness table T.

[0112] (5) According to the fifth embodiment, a method for estimating the release amount of gas G leaked from an inspection object 9 includes the following steps: detecting a jet F of gas G leaked from an inspection object based on an inspection image captured of the inspection object 9; measuring an outlet diameter representing the size of a jet outlet 91 of the inspection object based on the inspection image; calculating a flow velocity of a constant velocity core region P2 of the jet F based on the inspection image; calculating a volume of the jet F based on the outlet diameter and the flow velocity of the jet F; estimating a leakage gas concentration representing the concentration of the leaked gas G based on a brightness value of the constant velocity core region P2 in the inspection image and a gas concentration-brightness table T that determines a relationship between the concentration of the gas G and the brightness value of an image captured of the gas G; and estimating the release amount of the gas G based on the volume of the jet F and the leakage gas concentration.

[0113] (6) According to the sixth mode, the program causes the release amount estimation device 10 for estimating the release amount of gas G leaked from the inspection object 9 to perform the following steps: detecting the jet F of the gas G leaked from the inspection object based on the inspection image captured by the inspection object 9; measuring the outlet diameter representing the size of the jet outlet 91 of the inspection object based on the inspection image; calculating the flow velocity of the constant velocity core region P2 of the jet F based on the inspection image; calculating the volume of the jet F based on the outlet diameter and the flow velocity of the jet F; estimating the leakage gas concentration representing the concentration of the leaked gas G based on the brightness value of the constant velocity core region P2 in the inspection image and the gas concentration-brightness table T that determines the relationship between the concentration of the gas G and the brightness value of the image captured by the gas G; and estimating the release amount of the gas G based on the volume of the jet F and the leakage gas concentration.

[0114] Industrial Applicability

[0115] According to the above aspect, the amount of gas released from the inspection object can be estimated with high accuracy.

[0116] Explanation of symbols

[0117] 1-monitoring system, 9-gas piping (inspection object), 91-jet outlet, 10-release amount estimation device, 11-processor, 110-detection unit, 111-outlet diameter measurement unit, 112-speed calculation unit, 113-volume calculation unit, 114-concentration estimation unit, 115-release amount estimation unit, 12-memory, 13-storage device, 14-communication interface, 20-moving body, 30-camera, 8-test equipment, 80-test tube, 81-blackbody furnace, 82-concentration meter, 83-camera, P1-constant velocity nucleus, P2-constant velocity nucleus area, P3-fully developed area.

Claims

1. A release amount estimation device for estimating the release amount of gas leaked from an inspection object, the release amount estimation device comprising: a detection unit that detects a jet of the gas leaking from the inspection object based on an inspection image captured of the inspection object; an outlet diameter measuring unit that measures an outlet diameter indicating a size of a jet outlet of the inspection object based on the inspection image; a velocity calculation unit that calculates the flow velocity of the isovelocity core region of the jet flow based on the inspection image; a volume calculation unit, which calculates the volume of the jet flow according to the outlet diameter and the flow velocity of the jet flow; a concentration estimating unit that estimates a leaked gas concentration indicating the concentration of the leaked gas based on the brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table that defines a relationship between the concentration of the gas and the brightness value of an image capturing the gas; and The release amount estimating unit estimates the release amount of the gas based on the volume of the jet flow and the leaked gas concentration.

2. The release amount estimation device according to claim 1, wherein: The velocity calculation unit calculates the flow velocity of the constant velocity core area of ​​the jet based on the difference between the position of the feature point of the outer edge of the jet on the jet outlet side of the first inspection image among multiple inspection images and the position of the feature point in the second inspection image, which is an inspection image after any number of frames of the first inspection image.

3. The release amount estimation device according to claim 1, wherein: The gas concentration-brightness table has a plurality of different tables depending on the thickness of the gas. The concentration estimating section estimates a thickness of the leaked gas based on the outlet diameter, and estimates the leaked gas concentration based on the table corresponding to the estimated thickness of the gas.

4. The release amount estimation device according to any one of claims 1 to 3, wherein: In the concentration estimation unit, The leaked gas concentration is estimated based on an average value of the brightness values ​​of pixels within a predetermined range within the constant velocity core region. The size of the predetermined range is changed according to the flow velocity of the jet flow.

5. A method for estimating a release amount, which estimates the release amount of gas leaked from an inspection object, the method comprising the following steps: detecting a jet of the gas leaking from the inspection object based on an inspection image of the inspection object; measuring an outlet diameter indicating a size of a jet outlet of the inspection object based on the inspection image; calculating the flow velocity of the isovelocity core region of the jet flow according to the inspection image; Calculating the volume of the jet according to the outlet diameter and the flow rate of the jet; estimating a leaked gas concentration indicating the concentration of the leaked gas based on the brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table defining a relationship between the concentration of the gas and the brightness value of an image capturing the gas; and The amount of the gas released is estimated based on the volume of the jet and the concentration of the leaked gas.

6. A program that causes a release amount estimation device for estimating the release amount of gas leaked from an inspection object to execute the following steps: detecting a jet of the gas leaking from the inspection object based on an inspection image of the inspection object; measuring an outlet diameter indicating a size of a jet outlet of the inspection object based on the inspection image; calculating the flow velocity of the isovelocity core region of the jet flow according to the inspection image; Calculating the volume of the jet according to the outlet diameter and the flow rate of the jet; estimating a leaked gas concentration indicating the concentration of the leaked gas based on the brightness value of the constant velocity core region in the inspection image and a gas concentration-brightness table defining a relationship between the concentration of the gas and the brightness value of an image capturing the gas; and The amount of the gas released is estimated based on the volume of the jet and the concentration of the leaked gas.

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