JP6666183B2 - Gas visualization system, gas visualization method - Google Patents

Description

  The present invention relates to a gas visualization system and a gas visualization method.

  When a gas such as a flammable gas leaks (hereinafter simply referred to as a gas), it is necessary to find the leaking part as soon as possible and repair it. The leaked gas is constantly moving, and when there is air movement, it takes time to identify the position of the leak source. The gas sensor can detect a leaked gas by directly contacting the gas. However, since the behavior of the gas at that moment cannot be grasped, much time must be spent to identify the location of the leak source. To solve such a problem, Patent Literature 1 discloses a technique for visualizing leaked gas using infrared rays.

JP 06-288858 A

  In Patent Literature 1, the leak position is specified by visualizing the leak gas and grasping the gas flow. However, it is not easy to irradiate infrared rays with sufficient intensity over a wide range, and when the amount of leaking gas is small and the concentration is low, the effect of absorbing the infrared rays by the leaked gas becomes extremely small. Therefore, when the concentration of the leaked gas is low, it is not always possible to visualize the leaked gas and specify the position of the leaked gas. Therefore, there has been a demand for a technique capable of obtaining information effective for specifying a leakage position.

  The present invention has been made in view of the above, and provides a gas visualization system and a gas visualization method capable of visualizing low-concentration leaked gas and obtaining effective information for specifying a leakage position. Aim.

  In order to solve the above problems and achieve the object, a gas visualization system according to the present invention includes: an irradiation unit that irradiates light having a predetermined wavelength absorbed by a gas; a filter unit that transmits light having the predetermined wavelength; and An imaging unit that captures a background image and a measurement image via a filter unit, and calculates a difference value between a pixel value of a pixel forming the background image and a pixel value of a pixel forming the measurement image for each pixel. A difference data generation unit that generates a difference measurement image constituted by the difference values of pixels, and calculates, for each pixel, an integration pixel value that is a sum of the difference values obtained during the measurement, and calculates the integration of each pixel. A gas comprising: an integration data generation unit configured to generate an integrated measurement image configured by pixel values; and a visualization image generation unit configured to generate a visualized image obtained by superimposing the measurement image and the integration measurement image. Visualization Configured as a stem.

  The present invention is also understood as a gas visualization method used in the gas visualization system.

  According to the present invention, it is possible to visualize a low-concentration leak gas and obtain information effective for specifying a leak position.

It is a figure showing the example of composition of the gas visualization system in this embodiment. FIG. 4 is a diagram illustrating an example of information stored in a storage unit. It is a figure showing an example of measurement data. It is a figure showing an example of difference data. It is a figure showing an example of integral data. FIG. 4 is a diagram illustrating an example of background data. It is a figure showing the example of visualization image data. FIG. 3 is a block diagram illustrating a functional configuration of a control unit. It is a sequence diagram showing a processing procedure of a leak gas visualization processing.

  Embodiments of a gas visualization system and a gas visualization method according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration example of a gas visualization system 1000 according to the present embodiment. As shown in FIG. 1, the gas visualization system 1000 includes an irradiation unit 100, a filter unit 200, an imaging unit 300, and a computer 400. The irradiation unit 100, the imaging unit 300, and the computer 400 are electrically connected to each other by a connection line such as a bus.

  The irradiation unit 100 is, for example, an infrared light source including an LED (Light Emitting Diode) light source that emits infrared light. The filter unit 200 is, for example, a BPF (bandpass filter) that transmits only infrared light near the absorption wavelength of the gas to be visualized. The imaging unit 300 detects, for example, reflected light in which infrared light emitted from the back surface B or emitted from the irradiation unit 100 is reflected by the back surface B, and outputs an image including the detected reflected light via the filter unit 200. This is an infrared camera that captures images. The computer 400 is an information processing apparatus such as a PC (Personal Computer) that visualizes the leaked gas G using information output from the imaging unit 300, for example. As shown in FIG. 1, the computer 400 includes a display unit 401, an input unit 402, a storage unit 403, and a control unit 404.

  The display unit 401 is configured by a display device such as an LCD (Liquid Crystal Display), and displays various information including a visualized image obtained by visualizing the leaked gas. The input unit 402 includes, for example, an input device such as a keyboard, and accepts input of various information including a leak gas measurement instruction. The storage unit 403 includes, for example, a storage device or a storage medium such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various information related to the present system. The control unit 404 is configured from an arithmetic device such as a CPU (Central Processing Unit), and executes various processes related to the present system. Information stored in the storage unit 403 and processing executed by the control unit 404 will be described later.

  FIG. 2 is a diagram illustrating an example of information stored in the storage unit 403. As illustrated in FIG. 2, the storage unit 403 stores measurement data 4031, difference data 4032, integration data 4033, background data 4034, and visualized image data 4035.

  The measurement data 4031 is image data including the back surface B and the leaked gas G captured by the imaging unit 300. FIG. 3 is a diagram illustrating an example of the measurement data 4031. As shown in FIG. 3, the measurement data 4031 is a set of individual measurement images that are continuously accumulated from the start of the measurement of the leaked gas to the end thereof. FIG. 3 shows that one measurement image is accumulated in order from the measurement image f1 captured first after the measurement is started and the measurement of the leaked gas is completed. Further, in the measurement image f1, the leaked gas G is detected in the central portion on the near side of the back surface B, while in the measured image f2, the leaked gas G 'moved from the central portion on the near side of the back surface B to the right portion is detected. You can see that it is done. As described above, the measurement data 4031 stores the measurement images continuously captured from the start to the end of the measurement of the leaked gas.

  The difference data 4032 is data obtained by calculating a difference from the background data 4034 for each pixel for each measurement image forming the measurement data 4031. FIG. 4 is a diagram illustrating an example of the difference data 4032. As illustrated in FIG. 4, the difference data 4032 is a set of difference measurement images in which a difference from the background data 4034 is stored for each pixel configuring each of the l measurement images. In FIG. 4, for example, the difference measurement image f′1 is composed of mn pixels from the pixel (1, 1) to the pixel (m, n), and the pixel (2, 2) included in the measurement image The difference between the value and the pixel value of the pixel (2, 2) included in the background data 4034 is d1, and the value is stored as a difference value corresponding to the pixel (2, 2) of the difference measurement image. Is shown. Similarly, the difference between the pixel value of the pixel (2, 2) included in the measurement image f′2 and the pixel value of the pixel (2, 2) included in the background data 4034 is calculated as the pixel (2, 2) of the difference measurement image. It can be seen that it is stored as the difference value d2 of 2). In this manner, for each measurement image, the difference between the pixel value and the background data 4034 is calculated for each pixel, so that it is possible to grasp the change in the difference by looking at each pixel in time series.

  The integration data 4033 is data obtained by calculating the sum of the pixel values for each pixel of each difference measurement image forming the difference data 4032. FIG. 5 is a diagram illustrating an example of the integration data 4033. As shown in FIG. 5, the integral data 4033 is composed of an integral measurement image in which an integral pixel value, which is the sum of the pixel values of each pixel constituting one difference measurement image, is calculated. In FIG. 5, for example, it can be seen that the integral pixel value of the pixel (2, 2) included in the integral measurement image f ″ 1 is D1. Thus, the integral pixel value is calculated for each pixel of the integral measurement image. Therefore, it is possible to grasp how much each pixel is different from the background data 4034 based on the background data 4034.

  The background data 4034 is data serving as a reference for calculating the difference data 4032. FIG. 6 is a diagram illustrating an example of the background data 4034. As shown in FIG. 6, the background data 4034 is composed of mn pixels, like the difference data 4032 and the integral data 4033, and is a set of one background image, like the difference data 4032. In FIG. 6, for example, the background image f0 is composed of mn pixels from the pixel (1, 1) to the pixel (m, n), and the pixel value of the pixel (2, 2) included in the background image is r1. Is shown. A method for generating the background data 4034 will be described later.

  The visualized image data 4035 is data for finally displaying the leaked gas on the computer 400, and is data obtained by synthesizing each measurement image forming the measurement data 4031 and the integration measurement image forming the integration data 4033. is there. FIG. 7 is a diagram illustrating an example of the visualized image data 4035. As shown in FIG. 7, the visualized image data 4035 includes colored pixels classified according to the magnitude of the integral pixel values of the pixels constituting the integral measurement image (for example, a red pixel corresponding to the magnitude of the integral pixel value). Is changed), and the measurement image is superimposed and synthesized. In FIG. 7, the pixel (2, 2) included in the visualized image F1 is given a certain color (for example, the darkest red), and the pixel (2, 3) is given a certain color (for example, half the maximum red). Is attached. As described above, since each visualized image is colored according to the magnitude of the integrated pixel value that is the total amount of leaked gas for each pixel, the operator can determine at a glance where the leaked gas is located. Can be grasped. That is, since the position where the color is the darkest is considered to have the highest gas concentration, it is possible to obtain information effective for the specific work of the gas leak source.

  Next, the control unit 404 will be described. The control unit 404 is configured from an arithmetic device such as a CPU (Central Processing Unit), and executes various processes required for the present system. FIG. 8 is a block diagram illustrating a functional configuration of the control unit 404. As illustrated in FIG. 8, the control unit 404 includes a measurement execution unit 4041, a difference data generation unit 4042, an integration data generation unit 4043, a background data generation unit 4044, and a visualized image generation unit 4045. Have been.

  The measurement execution unit 4041 executes a leaked gas visualization process in accordance with an instruction received from the operator via the input unit 402. Specifically, the measurement data 4031 shown in FIG. 3 is output and stored in the storage unit 403. The difference data generation unit 4042 generates the difference data 4032 illustrated in FIG. 4 from the measurement data 4031 and the background data 4034. The integral data generation unit 4043 calculates the sum of the pixel values of the difference measurement image forming the difference data 4032, and generates the integral data 4044 shown in FIG. The visualized image generating unit 4045 superimposes and combines each of the measured images and the integral measured image to generate a visualized image.

  Subsequently, a leak gas visualization process performed by the present system will be described. FIG. 9 is a sequence diagram illustrating a processing procedure of the leak gas visualization processing. As shown in FIG. 9, in the present system, first, when the input unit 402 of the computer 400 receives an instruction to execute the leaked gas visualization processing from the operator (step S901), the measurement execution unit 4041 causes the irradiation unit 100 to perform an operation. On the other hand, an infrared irradiation instruction is output (step S902), and an imaging instruction with a camera is output to the imaging unit 300 (step S903).

  The irradiating unit 100 starts irradiating infrared rays according to the irradiating instruction (step S904), and the image capturing unit 300 starts image capturing by the camera according to the capturing instruction (step S905). After that, the irradiation of the infrared rays and the imaging by the camera are continuously executed until this processing ends.

  When imaging is started according to the imaging instruction, the imaging unit 300 outputs a measured image to the computer 400 (Step S906). Thereafter, the output of the measurement image is continuously executed until the present processing ends.

  The measurement execution unit 4041 receives the measurement images output from the imaging unit 300, and sequentially stores the measurement images in the storage unit 403 as measurement data 4031 (step S907). The background data generation unit 4044 generates the background data 4034 (Step S908). Here, a method of generating the background data 4034 will be described.

  Originally, it is desirable to use a background image when not affected by the leaked gas as the background data 4034. However, it is difficult to use the background image if a gas leak has already occurred at the time of arrival at the site after receiving the gas leak notification.

  Therefore, for example, the average value of the measurement images is used as the background image. As described above, the location of the leaked gas changes with time. Therefore, the background data generation unit 4044 calculates the pixel value of the measurement pixel for each measurement image obtained from the start to the end of the measurement, and is configured by a pixel value obtained by averaging the calculated pixel values of each measurement image. Set the image to be used as the background image. In this way, by setting the background image as the average value of the pixel values obtained from the measurement image, treating the difference between the value and the pixel value of the measurement image as an absolute value, and calculating the sum of the differences, Even when the influence of the gas is temporarily small (that is, the concentration is low), the leaked gas can be visualized.

  A background made of a material such as a wall usually emits infrared rays in proportion to the temperature. Therefore, when the temperature of the substance changes, the pixel value of the background image also changes. For example, when the background temperature is low, the emitted infrared light is weak. Therefore, it may not be possible to correctly determine whether such a change in infrared rays is caused by temperature or due to absorption of leaked gas. Since the change in the pixel value due to the low-concentration leak gas is small, the effect of the background temperature change cannot be ignored in an actual site. When the average of the measured images is used as the background image, the pixel values obtained by the temperature change are also integrated, so that the determination becomes more difficult. In practice, the change in the concentration of the leaked gas occurs in a short time, and the change in the background temperature is small during the short time.

  Therefore, for example, a measurement image that is a predetermined time before (for example, one second before) the latest measurement image is set as a background image, the absolute value of the difference between the two is calculated as a difference measurement image, and the sum is set as an integral measurement image. . By generating the background image in this way, the influence of the background temperature change can be eliminated. For example, the measurement image f2 shown in FIG. 3 is used as a background image, and the absolute value of the difference between the pixel value of each pixel forming the measurement image f2 and the pixel value of each pixel forming the latest measurement image f1 is calculated. , The difference measurement image shown in FIG.

  Furthermore, since an actual infrared camera image contains noise, if each pixel constituting the difference measurement image is simply integrated, the noise is also integrated together.

  Therefore, the average value of the pixel values of each pixel constituting the measurement image obtained within a certain period of time (for example, 1 second from 2 seconds to 1 second before) from a predetermined time before is calculated, and the average value is calculated as the background image. Good. By generating the background image in this way, the influence of noise can be eliminated. For example, an image obtained by calculating the average value of the pixel values of the pixels constituting the measurement image obtained from the measurement images fn to fn + m shown in FIG. The absolute value of the difference between the pixel value and the pixel value of each pixel constituting the calculated background image may be calculated to obtain the difference measurement image shown in FIG.

  The difference data generation unit 4042 compares the measurement image stored in the storage unit 403 with the background image, sequentially generates a difference measurement image in which a difference value is calculated for each pixel, and stores the difference measurement image in the storage unit 403 (step S909). .

  The integral data generation unit 4043 generates an integral measurement image in which the sum of the pixel values of the pixels corresponding to the difference measurement image is calculated (Step S910).

  The visualized image generation unit 4045 sequentially generates a visualized image obtained by synthesizing the measurement image and the integration measurement image, and displays the visualized image on the display unit 401 (step S911).

  The measurement execution unit 4041 determines whether the input unit 402 of the computer 400 has received an instruction to end the execution of the leaked gas visualization process from the operator (step S912), and determines that the execution end instruction has been received (step S912). (Step S912; Yes), the measurement execution unit 4041 outputs a laser irradiation end instruction to the irradiation unit 100 (Step S913), and outputs a camera imaging end instruction to the imaging unit 300 (Step S914). . On the other hand, when the measurement execution unit 4041 determines that the execution end instruction has not been received (step S912; No), the processing from step S906 is repeatedly executed.

  The irradiation unit 100 and the imaging unit 200 terminate their operations in accordance with instructions from the computer 400 (steps S915 and S916), and the measurement execution unit 4041 displays on the display unit 401 that the visualization processing has been completed (step S917). ).

  As described above, in the present system, since the above processing is executed, low-concentration leaked gas can be visualized, and information effective for specifying the position of the leaked gas can be obtained.

1000 Gas visualization system 100 Irradiation unit 200 Filter unit 300 Imaging unit 400 Computer 401 Display unit 402 Input unit 403 Storage unit 4031 Measurement data 4032 Difference data 4033 Integration data 4034 Background data 4035 Visualization image data 404 Control unit 4041 Measurement execution unit 4042 Difference data Generating unit 4043 Integration data generating unit 4044 Background data generating unit 4045 Visualized image generating unit.

Claims (6)

An irradiation unit that irradiates light of a predetermined wavelength absorbed by the gas,
A filter unit that transmits light of the predetermined wavelength,
An imaging unit that captures a background image and a measurement image via the filter unit,
Difference data generation for calculating a difference value between a pixel value of a pixel forming the background image and a pixel value of a pixel forming the measurement image for each pixel, and generating a difference measurement image formed by the difference value of each pixel Department and
An integrated data generation unit that calculates an integrated pixel value that is a sum of the difference values obtained during the measurement for each pixel, and generates an integrated measurement image configured by the integrated pixel value of each pixel,
A visualization image generation unit that generates a visualization image obtained by superimposing the measurement image and the integral measurement image,
A gas visualization system comprising: The gas visualization system, a background data generation unit that sets an average value of pixel values of the measurement image obtained during the measurement to the background image,
The gas visualization system according to claim 1, comprising: The gas visualization system, a background data generation unit that sets a measurement image obtained by measurement a predetermined time before the latest measurement image as the background image,
The gas visualization system according to claim 1, comprising: The gas visualization system calculates a mean value of pixel values of each pixel constituting a measurement image obtained by measurement for a predetermined time from a predetermined time before, and a background data generation unit configured to set the background image.
The gas visualization system according to claim 1, comprising: The visualized image generating unit generates the visualized image colored with each pixel according to the size of the integrated pixel value,
The gas visualization system according to any one of claims 1 to 4, wherein: Gas visualization having an irradiation unit that emits light of a predetermined wavelength absorbed by a gas, a filter unit that transmits the light of the predetermined wavelength, and an imaging unit that captures a background image and a measurement image via the filter unit. A gas visualization method performed in the system,
The difference between the pixel value of the pixel forming the background image and the pixel value of the pixel forming the measurement image is calculated for each pixel,
Generate a difference measurement image composed of the difference value of each pixel,
Calculate for each pixel an integrated pixel value that is the sum of the difference values obtained during the measurement,
Generating an integral measurement image composed of the integral pixel values of each pixel;
Generate a visualized image by superimposing the measurement image and the integral measurement image,
A gas visualization method comprising:

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