Image-based Mine Dust Monitoring Method

Abstract

The present invention provides an image-based mine dust monitoring method. The monitoring method adopts an open air chamber, does not require an air pump and dust treatment equipment, and an image acquisition device acquires a light source image. The difference in the brightness values ​​of infrared light and blue light is used to monitor dust. The method can effectively suppress the interference of color camera sensitivity changes, water mist, dirt, etc. on system monitoring values. Zero adjustment and system sensitivity calibration are not required, the method has high sensitivity, and is easy to install and maintain. The present invention also includes a method for automatically cleaning a lens cover and a light source cover, etc., which further ensures the accuracy of the system monitoring data. The method is particularly suitable for dusty environments underground and has a broad application space.

Description

Technical Field

[0001] The invention relates to an image-based mine dust monitoring method, which relates to the fields of digital image processing technology, automatic control technology and data processing technology. Background Art

[0002] Coal is the main energy source in my country, accounting for about 70% of primary energy. The coal industry is a high-risk industry. Accidents such as gas, floods, fires, roofs, and coal dust plague coal mine safety production. Among them, coal dust explosion accidents cause great damage and high casualties. Therefore, mine dust monitoring is an important guarantee for coal mine safety production and an important measure for the prevention and treatment of pneumoconiosis. At present, the main mine dust monitoring technologies include: friction electrostatic method, light scattering method, light absorption method, capacitance method, β-ray method, ultrasonic method, and microwave method. The measurement principle of the capacitance method is simple, but the capacitance measurement value and concentration are not a one-to-one linear relationship. The capacitance measurement value is easily affected by phase distribution and flow pattern changes, resulting in large measurement errors. Although the β-ray method is accurate, it requires sampling and comparative measurement of dust, and it is difficult to achieve online monitoring of dust concentration. The ultrasonic method and microwave method for measuring dust concentration are still in the experimental research stage, and there are few finished products on the market. At present, the light scattering method, light absorption method, and triboelectric method are mainly used in the market for online monitoring of dust concentration. The light scattering method and the light absorption method require the collection of dusty air through an air pump, and the dust particles in the air are processed and then poured into a closed air chamber for detection. The equipment structure is complex and the use and maintenance costs are high. The triboelectric method is greatly affected by wind speed. In order to ensure accurate and reliable monitoring of mine dust, a new mine dust monitoring technology with a simple structure, low use and maintenance costs, and accurate detection is needed. Summary of the invention

[0003] With the improvement of digital image processing technology, image-based data processing technology has been greatly developed. On this basis, the present invention proposes an image-based mine dust monitoring method suitable for wide promotion, which is specifically as follows: light sources and color image acquisition devices are respectively arranged on the sides of the mine tunnel, and the light sources are directed to the color image acquisition devices; the light sources include infrared light emitting elements, blue light emitting elements and transparent light source covers; the color image acquisition devices include transparent lens covers; the lens covers and light source covers are automatically or manually cleaned at set intervals; the light source images of the infrared light emitting elements and the blue light emitting elements are respectively collected by the color image acquisition devices, the images are respectively processed, and dust is measured according to the brightness of the light sources in the images; the process of the mine dust monitoring method is as follows:

[0004] (1) Measure the distance l between the light source and the color image acquisition device;

[0005] (2) Turn off the automatic white balance function of the color image acquisition device and fix the focal length and aperture;

[0006] (3) Clean the lens cover and light source cover;

[0007] (4) controlling the infrared light emitting element and the blue light emitting element of the light source to emit light respectively, and the color image acquisition device to acquire images including the light source respectively;

[0008] (5) Process the images separately to obtain the light source brightness d of the infrared light emitting element and the blue light emitting element respectively. R ,d B ;

[0009] (6) x = d R -d B Substitute y=f(x) to get y, and correct the y value according to the distance l to get the dust concentration;

[0010] (7) Repeat steps (4), (5) and (6) to perform image acquisition and dust concentration measurement; when the system operation time reaches the set interval time, return to execute step (3) and the following steps.

[0011] 1. The dust monitoring method further includes: the method for obtaining the dust concentration calculation formula y=f(x) is specifically:

[0012] (1) In a dust-free and closed environment, a light source with a dust-free light source cover and a color image acquisition device with a dust-free lens cover are respectively arranged at a set interval, and the light source is directed toward the color image acquisition device;

[0013] (2) Turn off the automatic white balance function of the color image acquisition device and fix the focal length and aperture;

[0014] (3) Control the infrared light emitting element and the blue light emitting element of the light source to emit light respectively, control the image acquisition device to respectively acquire images containing the light source, process the images respectively, and obtain the dust-free light source brightness d of the set area in the infrared light emitting element and the blue light emitting element light source images respectively. R0 ,d B0 , record d R0 -d B0 value;

[0015] (4) Spray different concentrations of dust and air mixture in a closed environment to make the dust concentration reach N set values ​​y i , i = 1 ~ N, each time a set value y is reached i When the infrared light emitting element and the blue light emitting element of the light source are controlled to emit light respectively, the color image acquisition device is controlled to acquire the image containing the light source, and the images are processed respectively to obtain the dust light source brightness d of the set area in the infrared light emitting element and the blue light emitting element light source image. Ri ,dBi , record d Ri -d Bi value, get y i With d Ri -d Bi The corresponding data table of the value;

[0016] (5) The brightness value of the dusty light source obtained in step (4) corresponds to the data table and the brightness of the dust-free light source obtained in step (3) R0 -d B0 The value is fitted to obtain the dependent variable y with the dust setting value as the light source brightness difference d in the set area R -d B The function formula y=f(x) is the independent variable x.

[0017] 2. The dust monitoring method further includes: a method for cleaning the lens cover and the light source cover includes cleaning by cleaning liquid and an automatic cleaning brush, automatic ultrasonic cleaning equipment, high-pressure water equipment or high-pressure air equipment.

[0018] 3. The dust monitoring method further includes: the system also includes a humidity sensor, and the control device corrects the detected dust concentration according to the humidity value.

[0019] 4. The dust monitoring method further comprises: a method for measuring the distance between the light source and the color image acquisition device comprises manual distance measurement or automatic distance measurement by a laser rangefinder.

[0020] The beneficial effects achieved by the present invention are as follows: the mine dust measurement of the present invention adopts an open air chamber, and does not require an air pump and dust treatment equipment. Dust detection is completed directly through image processing, and the system structure is simple; dust monitoring is performed by utilizing the difference in the brightness values ​​of infrared light and blue light, which can effectively suppress the interference of color camera sensitivity changes, water mist and dirt on the system monitoring values, and does not require zeroing and system sensitivity calibration. It has high sensitivity and is easy to install and maintain; the present invention also proposes a method for automatically cleaning the lens cover and the light source cover, which further ensures the accuracy of the system monitoring data, is particularly suitable for dusty environments underground, and has a broad application space. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the system implementation example of the image-based mine dust monitoring method.

[0022] Figure 2 Workflow diagram of the image-based mine dust monitoring method.

[0023] Figure 3 Workflow diagram for obtaining dust measurement formula for image-based mine dust monitoring method. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the application embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] An example of a system implementation of the image-based mine dust monitoring method is as follows: Figure 1 As shown, the system consists of:

[0026] 1. The controller (101) is the core control and data processing device of the system. It is responsible for controlling the light source, camera, light source cover cleaning device, and lens cover cleaning device, collecting and processing the humidity data of the humidity sensor and the video image data of the camera, realizing dust monitoring, light source cover and lens cover cleaning, etc. It is also responsible for communicating with the well equipment, sending the dust monitoring data to the well equipment, and receiving the control instructions sent by the well equipment. The controller has a wireless or wired communication interface for collecting relevant data required for manual distance measurement of the system. The controller has a display screen and buttons for displaying data and working status. The controller has an alarm element with sound and light alarm functions.

[0027] 2. The humidity sensor (102) is connected to the controller via a communication cable to provide humidity data to the controller.

[0028] 3. A light source (103), including infrared light and blue light emitting elements, which can be controlled to emit light independently, and can use infrared LED and blue LED. The light source has a light source cover.

[0029] 4. Light source cover cleaning equipment (104), used for cleaning the light source cover, can use cleaning liquid and automatic cleaning brush, automatic ultrasonic cleaning equipment, high pressure water equipment or high pressure air equipment for cleaning. The light source cover cleaning equipment is connected to the controller through a communication cable and is controlled by the controller.

[0030] 5. A lens cover cleaning device (105) is used to clean the lens cover of a camera. The device has the same principle as the light source cover cleaning device (104). The cleaning device can be cleaned by using a cleaning fluid and an automatic cleaning brush, an automatic ultrasonic cleaning device, a high-pressure water device or a high-pressure air device. The light source cover cleaning device is connected to the controller via a communication cable and is controlled by the controller.

[0031] 6. Camera (106), i.e., color image acquisition device, capable of acquiring visible light color images and infrared images, and equipped with a lens cover.

[0032] An example of workflow implementation of an image-based mine dust monitoring method is shown below: Figure 2 As shown:

[0033] (201) manually measuring the distance between the light source and the image acquisition device or automatically measuring the distance between the light source and the image acquisition device by a laser rangefinder, and collecting the distance data by a controller;

[0034] (202) Turn off the automatic white balance function of the image acquisition device, fix the focal length and aperture, and lock the camera parameters;

[0035] (203) Manual or automatic cleaning of lens cover and light source cover;

[0036] (204) the control device controls the infrared light emitting element of the light source to emit light;

[0037] (205) the control device controls the camera to collect an image containing an infrared light source;

[0038] (206) Process the light source image to obtain the infrared brightness d of the light source area R ;

[0039] (207) The control device controls the blue light emitting element of the light source to emit light;

[0040] (208) The control device controls the camera to capture an image containing a blue light source;

[0041] (209) Process the light source image to obtain the blue light brightness d of the light source area B ;

[0042] (210) x = d R -d B Substituting y=f(x), we get y;

[0043] (211) The y value is corrected according to the distance l to obtain the dust concentration;

[0044] (212) Determine whether the system running time has reached the set interval time. If it has reached the set interval time, return to (203)

[0045] Reclean the lens cover and light source cover; otherwise, return to (204) to perform image acquisition and dust concentration measurement.

[0046] An example of a workflow implementation of the dust measurement formula obtained by the image-based mine dust monitoring method is as follows: Figure 3 As shown, the light source and the color image acquisition device are devices used on-site or devices with the same model and parameters as the on-site devices.

[0047] (301) In a dust-free and closed environment, a light source with a dust-free light source cover and a color image acquisition device with a dust-free lens cover are respectively arranged at a set interval, and the light source is irradiated toward the color image acquisition device;

[0048] (302) Turn off the automatic white balance function of the image acquisition device, fix the focal length and aperture, and lock the camera parameters;

[0049] (303) the control device controls the infrared light emitting element of the light source to emit light;

[0050] (304) controlling a color image acquisition device to acquire an image containing an infrared light source;

[0051] (305) Process the image containing the infrared light source to obtain the infrared light brightness d of the light source area R0 ;

[0052] (306) The control device controls the blue light emitting element of the light source to emit light;

[0053] (307) controlling a color image acquisition device to acquire an image containing a blue light source;

[0054] (308) Process the image containing the blue light source to obtain the blue light brightness d of the light source area B0 ;

[0055] (309) Record d R0 -d B0 value;

[0056] (310) Spray different concentrations of dust and air mixture in a closed environment to make the dust concentration reach the set value y i , i=1~N, y1~y N It is a sequence of set values ​​from low to high. When this step is executed for the first time, the set value is y1;

[0057] (311) the control device controls the infrared light emitting element of the light source to emit light;

[0058] (312) controlling a color image acquisition device to acquire an image containing infrared light;

[0059] (313) Process the image containing infrared light to obtain the infrared light brightness d of the light source area Ri ;

[0060] (314) The control device controls the blue light emitting element of the light source to emit light;

[0061] (315) controlling a color image acquisition device to acquire an image containing blue light;

[0062] (316) Process the image containing blue light to obtain the blue light brightness d of the light source area Bi ;

[0063] (317) Record d Ri -d Bi value;

[0064] (318) Determine whether y is completed i The value d of all dust concentration setting values ​​in the sequence Ri -d Bi If all records are completed, execute (320), otherwise execute (319);

[0065] (319) Change to a higher dust concentration setting value y i , and returns (310);

[0066] (320) Statistics get y i With d Ri -d Bi The corresponding data table of the value;

[0067] (321) The data table corresponding to the light source brightness difference obtained in step (320) and the dust-free light source brightness obtained in step (309) are calculated. R0 -d B0 The value is processed and fitted to obtain the dependent variable y with the dust setting value and d R -d B The function formula y=f(x) is the independent variable x.

Claims

1. An image-based mine dust monitoring method, characterized in that: A light source and a color image acquisition device are respectively arranged on the sides of the mine tunnel, and the light source shines on the color image acquisition device; the light source includes an infrared light emitting element, a blue light emitting element and a transparent light source cover; the color image acquisition device includes a transparent lens cover; the lens cover and the light source cover are automatically or manually cleaned at set intervals; the light source images of the infrared light emitting element and the blue light emitting element are respectively acquired by the color image acquisition device, and the images are processed respectively, and dust is measured according to the brightness of the light source in the image; the process of the mine dust monitoring method is: (1) Measure the distance l between the light source and the color image acquisition device; (2) Turn off the automatic white balance function of the color image acquisition device and fix the focal length and aperture; (3) Clean the lens cover and light source cover; (4) controlling the infrared light emitting element and the blue light emitting element of the light source to emit light respectively, and the color image acquisition device to acquire images including the light source respectively; (5) Process the images separately to obtain the light source brightness d of the infrared light emitting element and the blue light emitting element respectively. R d B ; (6) x = d R -d B Substitute y=f(x) to get y, and correct the y value according to the distance l to get the dust concentration; (7) Repeat steps (4), (5) and (6) to collect images and measure dust concentration; when the system operation time reaches the set interval time, return to execute step (3) and the following steps; The system includes a humidity sensor, and the control device corrects the detected dust concentration according to the humidity value; The method for measuring the distance between the light source and the image acquisition device in step (1) includes manual distance measurement or automatic distance measurement by a laser rangefinder; The method for obtaining the formula of step (6) is specifically as follows: (1) In a dust-free and closed environment, a light source with a dust-free light source cover and a color image acquisition device with a dust-free lens cover are respectively arranged at a set interval, and the light source is directed toward the color image acquisition device; (2) Turn off the automatic white balance function of the color image acquisition device and fix the focal length and aperture; (3) Control the infrared light emitting element and the blue light emitting element of the light source to emit light respectively, control the image acquisition device to respectively acquire images containing the light source, process the images respectively, and obtain the dust-free light source brightness d of the set area in the infrared light emitting element and the blue light emitting element light source images respectively. R0 d B0 , record d R0 -d B0 value; (4) Spray different concentrations of dust and air mixture in a closed environment to make the dust concentration reach N set values ​​y i , i = 1 ~ N, each time a set value y is reached i When the infrared light emitting element and the blue light emitting element of the light source are controlled to emit light respectively, the color image acquisition device is controlled to acquire the image containing the light source, and the images are processed respectively to obtain the dust light source brightness d of the set area in the infrared light emitting element and the blue light emitting element light source image. Ri d Bi , record d Ri -d Bi value, get y i With d Ri -d Bi The corresponding data table of the value; (5) The brightness value of the dusty light source obtained in step (4) corresponds to the data table and the brightness of the dust-free light source obtained in step (3) R0 -d B0 The value is fitted to obtain the dependent variable y with the dust setting value and the light source brightness difference d in the set area R -d B The function formula y=f(x) is the independent variable x.

2. The dust monitoring method according to claim 1, characterized in that: Methods for cleaning the lens cover and the light source cover include cleaning with a cleaning fluid and an automatic cleaning brush, an automatic ultrasonic cleaning device, a high-pressure water device, or a high-pressure air device.

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