Device and method for simultaneously measuring movement rules of particles of two materials in sand flow

Abstract

The invention relates to a device and a method for simultaneously measuring the movement rules of particles of two materials in a wind-sand flow. The measuring method comprises the following steps: S1, arranging the device for simultaneously measuring the movement rules of the particles of the two materials in the wind-sand flow; particles of a to-be-tested material and particles of another dyed to-be-tested material are laid in the particle placement area; s2, ensuring that the two cameras have overlapped view fields by using a scale, and determining the positions of the overlapped view fields; s3, adjusting the time interval of two adjacent frames of images according to the wind speed; s4, a fan is started, the computer sends starting signals to the laser emission subunits and the cameras respectively, and the two cameras shoot particle motion images respectively and send the particle motion images to the computer; s5, calculating the coordinates of the particles of the two to-be-detected materials according to the coordinates of the overlapped view field and the images shot by the two cameras; s6, according to the coordinates of the dyed particles and the coordinates of the undyed particles, the movement rules corresponding to the particles of the two materials are determined. According to the invention, the movement rules of particles of two materials can be observed at the same time.

Description

Technical Field

[0001] The present invention relates to a method for measuring the movement law of particles, and more specifically, to an apparatus and method for simultaneously measuring the movement laws of particles of two materials in a sand-dust flow. Background Art

[0002] Sand-dust environments are widely distributed in many regions of the world, covering deserts, gobi, and many arid and semi-arid zones. The sand-dust phenomenon is essentially a complex movement process of a large amount of particulate matter under the action of air flow, and in-depth exploration of it is of great importance that cannot be ignored. The movement of sand-dust particles has an important impact on the ecosystem. On the one hand, sand-dust may carry nutrients and provide fertility for the soil in some areas; on the other hand, sand-dust may also bury vegetation and affect the growth and distribution of plants. For example, microplastics (<5 mm plastic fragments) are widely distributed in various geospheres. Among them, due to the widespread use of agricultural plastic films and the input of sewage sludge, the abundance of microplastics in the soil is high. Under the action of wind, the migration process of microplastics may lead to their widespread distribution and spread in the environment, causing serious environmental pollution problems and ecological damage.

[0003] Currently, the technical means directly for observing the velocity of sand-dust particles mainly include: Particle Dynamics Analyzer (PDA) and Laser Doppler Velocimetry (LDV) based on the optical Doppler effect, as well as High-Speed Photometry (HSP), Particle Image Velocimetry (PIV), and Particle Tracking Velocimetry (PTV) based on image processing. However, the above methods cannot simultaneously measure the movement laws of particles of two materials. Summary of the Invention

[0004] One of the purposes of the present invention is to provide an apparatus for simultaneously measuring the movement laws of particles of two materials in a sand-dust flow, so as to provide an apparatus for accurately measuring the movement laws of particles of two materials simultaneously.

[0005] Another purpose of the present invention is to provide a method for simultaneously measuring the movement laws of particles of two materials in a sand-dust flow, so as to solve the problem that the existing technologies for measuring the movement laws of particles cannot simultaneously measure the movement laws of particles of two materials.

[0006] One of the purposes of the present invention is achieved as follows:

[0007] An apparatus for simultaneously measuring the movement laws of particles of two materials in a sand-dust flow includes: a sand-dust flow simulation unit and a measurement unit arranged on its side;

[0008] The sand-drift flow simulation unit has a hair dryer connected to one end of a square tubular transparent housing. Inside the housing, a mesh plate and roughness elements are arranged in sequence along the incoming wind direction. The mesh plate is a square plate body, and its four sides are sealed to the inner wall of the housing. The roughness elements are fixed to the inner surface of the bottom layer of the housing, and the inner surface area of the bottom layer of the housing behind the roughness elements is the particle placement area;

[0009] The measurement unit includes a synchronous controller, a laser emission sub-unit, two cameras, and a computer; the two cameras are arranged side by side and face the end of the particle placement area of the housing, and a fluorescence filter is provided on any one of the cameras; the laser emission sub-unit and the two cameras are both electrically connected to the synchronous controller, the synchronous controller and the computer are electrically connected, and the laser irradiation center of the laser emission sub-unit and the focus points of the two cameras are on the same plane.

[0010] Further, the laser emission sub-unit includes a double-pulse laser, a light guide arm, and a laser emission component. The two ends of the light guide arm are respectively connected to the double-pulse laser and the laser emission component. The laser emission component is arranged above the end of the particle placement area, and the laser plane formed by the light beam emitted by the laser emission component is parallel to the incoming wind direction of the blower.

[0011] Further, an anemometer is also provided on the inner wall of the housing.

[0012] Further, the distance between the two cameras is 2 - 3 cm.

[0013] Further, the laser wavelength and the filter used by the laser emission sub-unit are both matched with the dye used for the dyed particles.

[0014] The second object of the present invention is achieved as follows:

[0015] A method for simultaneously measuring the movement laws of particles of two materials in a sand-drift flow, comprising the following steps:

[0016] S1. Set up the device for simultaneously measuring the movement laws of particles of two materials in a sand-drift flow described in the first object of the present invention; lay particles of two materials to be measured in the particle placement area, and one of the particles to be measured is dyed particles;

[0017] S2. Calibrate the cameras using a scale to make the two cameras have overlapping fields of view, and determine the positions of the overlapping fields of view in the images taken by the two cameras respectively;

[0018] S3. Adjust the time interval between two adjacent frames according to the wind speed;

[0019] S4. Turn on the fan, and the computer sends a start signal to the laser emission subunit and the camera through the synchronous controller; the laser emission subunit emits lasers, and the two cameras take motion images of the particles and send the motion images to the computer;

[0020] S5. measuring the coordinates of particles of the two materials to be tested according to the particle motion images captured by the two cameras and the coordinates of the overlapping fields of view;

[0021] S6. Determine the movement speed of the particles of the dyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images; determine the movement speed of the undyed particles of the undyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images.

[0022] Furthermore, the specific method of determining the overlapping field of view position in step S2 is:

[0023] S2-1. Fix the ruler vertically on the bottom surface of the tail end of the shell particle placement area;

[0024] S2-2. Adjust the two cameras to the same focal length; take pictures with the two cameras respectively, and determine the coordinates of the ruler according to the images taken by the two cameras;

[0025] S2-3. Determine the length of the overlapping field of view according to the horizontal coordinate of the ruler on the two images, and determine the height of the overlapping field of view according to the vertical coordinate of the ruler on the two images;

[0026] S2-4. Determine the positions of the overlapping fields of view in the images captured by the two cameras according to the length and height of the overlapping fields of view.

[0027] Furthermore, the specific method of determining the particle coordinates of the two materials to be tested in step S5 is:

[0028] S5-1. Establishing coordinate systems for the images captured by the two cameras respectively; calculating the coordinate relationship of the images captured by the two cameras according to the overlapping fields of view at the positions of the images captured by the two cameras respectively;

[0029] S5-2. Determine the coordinates of the particles according to the image captured by the camera with the filter;

[0030] S5-3. Determine the coordinates of the particles of the dyed material to be tested in the image taken by the camera without a filter according to the coordinate relationship and the coordinates of the particles in the overlapping field of view in the image taken by the camera with a filter;

[0031] S5-4. Based on the coordinates of all particles in the overlapping field of view in the image taken by the camera with a filter, the coordinates of the stained particles taken by the camera without a filter are eliminated, and the coordinates of the remaining particles are the coordinates of the unstained particles being measured.

[0032] The present invention provides a device for simultaneously measuring the movement law of particles of two materials in a wind-sand flow, uses a screen in a wind-sand flow simulation environment to make the wind output by the fan more uniform, and provides a rough element on the bottom surface inside the shell to make the wind condition inside the shell more consistent with the actual wind condition. A transparent shell is used to facilitate camera shooting. The filter and the laser emission subunit are matched with the dye used for the particles, and the particles of the two materials are more easily distinguished in the images taken by the camera. Two cameras take pictures at the same time, and the two images at the same time have the same particles. The device of the present invention has a simple structure and is easy to implement.

[0033] The present invention dyes particles of one of the two materials, and the laser emission subunit irradiates the mixed particles, so that the dyed particles emit fluorescence, which is convenient for the camera with a filter to capture. The camera with a filter captures the motion image of the dyed particles of the material to be tested, and the camera without a filter captures the motion image of the particles of the two materials to be tested. Ensure that the two cameras have overlapping fields of view, use a synchronous controller to make the two cameras shoot at the same time, calculate the motion law of the two particles in the overlapping field of view, and only need to remove the dyed particles of the material to be tested in the overlapping field of view to obtain the motion image of the undyed particles of the material to be tested in the overlapping field of view, without the need to measure the particles of each material separately, saving time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural diagram of the device of the present invention.

[0035] Figure 2 It is a flow chart of the method of the present invention.

[0036] Figure 3 It is a schematic diagram of overlapping field of view.

[0037] Among them, 1. wind and sand flow simulation unit; 2. measurement unit; 11. shell; 12 mesh plate; 13. rough element; 14 anemometer; 21. camera; 22. synchronization controller; 23. computer; 241. double-pulse laser; 242. light guide arm; 243. laser emitting component. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings.

[0039] like Figure 1 As shown, the present invention provides a device for simultaneously measuring the movement law of particles of two materials in a wind-sand flow, comprising a wind-sand flow simulation unit 1 and a measurement unit 2 on the side thereof.

[0040] One end of the square tubular transparent shell 11 of the wind and sand flow simulation unit is connected to a hair dryer, and a mesh plate 12 and a rough element 13 are arranged inside the shell 11 along the incoming wind direction. The mesh plate 12 is a square plate body, and its four sides are sealed to the inner wall of the shell 11. The rough element 13 is fixed on the inner bottom surface of the shell 11, and the inner surface area of ​​the bottom layer of the shell behind the rough element 13 is the particle placement area.

[0041] The rough element 13 is a cube, a cuboid or a cone of different heights made of wood blocks. The placement and shape of the rough element 13 are constantly changed in the wind and sand flow simulation device 1 until the wind speed distribution of the wind tunnel section meets the logarithmic distribution law, so that the average wind speed profile curve becomes smoother and the wind condition in the housing 11 is more in line with the actual wind condition in the field. The mesh plate 12 is made of iron wire, and the side length of the mesh is 1 cm, which is evenly distributed on the mesh plate 12.

[0042] The measuring unit 2 includes a synchronous controller 22, a laser emission subunit, two cameras 21 and a computer 23. The two cameras 21 face the shell and are arranged side by side at the end of the particle placement area. A fluorescent filter is arranged on any camera. The dual-pulse laser subunit and the two cameras 21 are electrically connected to the synchronous controller 22 respectively. The synchronous controller 22 is also electrically connected to the computer 23. The laser irradiation center of the dual-pulse laser subunit and the focusing points of the two cameras 21 are in the same plane.

[0043] An anemometer is also provided on the inner wall of the housing 11 .

[0044] Among them, the laser emitting subunit includes a dual-pulse laser 241, a light guide arm 242 and a laser emitting component 243. The dual-pulse laser 241 transmits the laser to the laser emitting component through the light guide arm 242. The light guide arm 242 can be flexibly bent and rotated so that the laser irradiation center of the laser emitting component 243 and the focusing points of the two cameras are in the same plane, and the laser surface formed by the light beam emitted by the laser emitting component is parallel to the wind direction of the fan.

[0045] The distance between the cameras 21 is 2-3 cm, and the laser wavelength and filter used by the double-pulse laser 241 are matched with the dye used for the particles of the material to be tested. For example, when using Nile red dye to dye the particles of the type to be tested, it is necessary to select a laser emission wavelength of 488 nm; and use a filter that only allows light of 580 nm-650 nm to pass through. When using rhodamine B to dye the particles of the type to be tested, select a laser emission wavelength of 532 nm and use a filter that allows light of 570 nm-620 nm to pass through.

[0046] The camera used in the present invention is a CCD camera.

[0047] like Figure 2As shown, the present invention also provides a method for simultaneously measuring the particle movement law of two materials in a wind-sand flow, comprising the following steps:

[0048] S1. A device is provided for simultaneously measuring the movement law of particles of two materials in a wind-sand flow; particles of two materials to be measured are laid in a particle placement area, wherein particles of one material to be measured are dyed particles.

[0049] In the wind tunnel, particles of two materials to be tested are placed according to the experimental requirements to simulate the situation in the actual environment, and a dye is used to dye the particles of one of the materials to be tested. The particles of the two materials to be tested used in the present invention are quartz sand and microplastics, the quartz sand is 40-80 mesh black quartz sand, the microplastics are polyvinyl chloride (PVC) dyed with 0.2g / L rhodamine B dyeing solution using ethanol as a solvent, and a microplastic mixed soil sample is prepared according to a ratio of 1:20 dyed microplastics to quartz sand, and a sand bed is laid to keep the bed surface flat.

[0050] Undyed particles of the material to be tested and another dyed particle of the material to be tested are spread flat in a particle placement area in the shell of the wind-sand flow simulation device.

[0051] S2. Calibrate the camera 21 using a ruler so that the two cameras have overlapping fields of view, and determine the coordinates of the overlapping fields of view.

[0052] Adjust the two cameras to the same focal length, and fix the ruler vertically at the end of the particle placement area in the shell, in the same plane as the focus points of the two cameras 21. When both cameras can capture the ruler, it means that the cameras have overlapping fields of view. When one camera captures the ruler and the other does not, it means that the two cameras do not have overlapping fields of view. Reduce the distance between the two cameras. You can also adjust the size of the overlapping field of view by adjusting the distance between the two cameras.

[0053] like Figure 3 As shown, after determining that the two cameras have overlapping fields of view, the ruler is used as the calibration center, and the sum of the area between the ruler and the right boundary in the image taken by the left camera, and the area between the ruler and the left boundary in the image taken by the right camera, is the overlapping field of view of the two cameras. The two cameras take pictures at the same time, determine the actual shooting range and zoom factor of camera 21, establish coordinate systems for the images taken by the two cameras, determine the horizontal coordinates of the ruler in the images taken by the two cameras 21, determine the distance from the ruler to the boundaries of the two images according to the coordinates of the ruler, determine the length of the overlapping field of view by the distance from the ruler to the two boundaries, determine the height difference of the images taken by the two cameras according to the vertical coordinates of the ruler in the two images, and determine the height of the overlapping field of view according to the actual shooting range of the camera and the image height difference. After completion, remove the ruler.

[0054] The coordinates of a ruler are the coordinates of a point on the ruler, for example, the 0 scale line.

[0055] For example, the image scale factor of the camera is 0.047mm / pix, the range captured by the two cameras is 6600*4400pix, which is a rectangular area of ​​300mm*210mm. The coordinates of the ruler in the image captured by the left camera are (3542, 854), and the coordinates of the ruler in the image captured by the right camera are (1437, 1034). The camera capture length range is 6600, so the distance between the ruler and the right border of the image captured by the left camera is 3058 pixels, the length of the overlapping field of view is 4495 pixels, and the height difference between the two cameras is 180 pixels, so the height of the overlapping field of view is 4220 pixels, that is, the overlapping field of view area is a rectangular area of ​​210mm*198mm.

[0056] Therefore, based on the actual size of the shooting area, it can be obtained that the lower left corner of the overlapping field of view is 98.935 mm to the right of the left boundary of the image taken by the left camera, 8.46 mm above the lower boundary, and the upper right corner is at the upper right corner of the image taken by the left camera. The lower left corner of the overlapping field of view is at the lower left corner of the image taken by the right camera, and the upper right corner is 210 mm to the right of the left boundary of the image taken by the right camera, and 198 mm above the lower boundary.

[0057] Before determining the coordinates of the overlapping fields of view, first find the maximum overlapping fields of view of the two cameras, adjust the two cameras to the same parameters, and adjust the image scaling ratios of the two cameras and the distances between the cameras and the sand flow simulation device. Each time the overlapping fields of view of the two cameras are determined, the parameters corresponding to the larger overlapping fields of view are used as the parameters of the two cameras.

[0058] S3. Adjust the time interval between two adjacent image frames according to the wind speed.

[0059] The camera 21 uses a convex lens to convert a point light source into a sheet light source, and adjusts the shooting width according to the particle size, etc. The narrowest part of the shooting center is 1 mm.

[0060] First, adjust the fan to the target wind speed and adjust the time interval between two adjacent frames of images so that the distance between the same particle in two adjacent frames is 6-10 pix, to ensure that the same particle can be recorded simultaneously and correlated in two adjacent frames of images.

[0061] The time interval used in the present invention is 67-133 us.

[0062] Whether the particles can be photographed also depends on the brightness of the laser beam output by the laser emission subunit. Before adjusting the time interval between two adjacent frames of images, adjust the brightness of the laser beam output by the laser emission subunit until the dyed particles can be clearly observed.

[0063] S4. Turn on the fan, and the computer 23 sends a start signal to the laser emission subunit and the camera 21 through the synchronization controller 22; the two cameras 21 respectively capture the motion images of the particles and send the motion images to the computer 23.

[0064] The fan is turned on, and when the wind speed reaches the target wind speed (10-20 seconds), the computer sends the shooting signal to the synchronous controller, and the synchronous controller sends the control signal to the dual-pulse laser and the two cameras respectively. The dual-pulse laser 241 transmits the laser to the laser emitting component through the light guide arm 242, and the laser emitting component 243 emits the laser, which can make the dyed particles emit fluorescence. The two cameras 21 shoot at the same time and send the captured images to the computer 23. The whole process is recorded for 1 minute to obtain two sets of images.

[0065] S5. According to the particle motion images captured by the two cameras and the coordinates of the overlapping fields of view, the coordinates of the particles of the two materials to be tested are measured.

[0066] The position of the same particle captured by the camera at the same time is the same. The particles captured by the camera with filter are the particles of the dyed material to be tested, and the particles captured by the camera without filter are particles of two materials to be tested. The particles of the dyed material to be tested are removed from the overlapping area of ​​the image captured by the camera without filter to obtain the coordinates of the particles of the other material to be tested. When calculating, only the coordinates of the particles in the overlapping field of view need to be calculated.

[0067] The coordinates of the images taken by the two cameras are established. The coordinate system established for the images taken by the same camera is the same. According to the coordinates of the images taken by the two cameras, the coordinate relationship of the images taken by the two cameras is established. The coordinate relationship includes the horizontal coordinate relationship and the vertical coordinate relationship. For example, the camera shooting range is 300mm*210mm and the overlapping field of view area is 210mm*198mm. The coordinate origin is established in the upper left corner of the image taken by the two cameras. The horizontal coordinate correspondence between the two cameras is x 2 =0.9853x 1 -112.13, the vertical coordinate corresponds to y 2 =0.9949y 1 +0.8803, where x 1 and 1 is the coordinate of the camera with filter, x 2 and 2 are the coordinates of the camera without filter.

[0068] In order to reduce the error, the movement information of microplastics and quartz sand is extracted from the image of the mixture particles. According to the position of the particles in the overlapping field of view of the images taken by the camera with filter and the corresponding coordinate relationship, the image of the dyed particles in the overlapping field of view of the images taken by the camera without filter is determined, and the position of the dyed particles is calculated and recorded. The dyed particles in the overlapping field of view of all particles in the overlapping field of view of the images taken by the camera without filter are removed, and the remaining particles are the particles of the undyed material to be tested. The image of the undyed particles in the overlapping field of view of the images taken by the camera without filter is obtained, and the position of the particles of the undyed material to be tested is recorded according to the established coordinate system.

[0069] S6. Determine the movement speed of the particles of the dyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images; determine the movement speed of the undyed particles of the undyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images.

[0070] The brightness and size of the same particle are the same, and the displacement of the same particle in two adjacent frames is 6-10 pix. The above information can be used to obtain the same particle in the next frame.

[0071] According to the coordinates of the same particle in two adjacent frames, the particle movement speed is calculated using the following formula:

[0072]

[0073] Among them, U x is the horizontal velocity of the particle, U y is the longitudinal velocity of the particle, (x 1 ,y 1 ) is the coordinate of the particle on the first image, (x 2 ,y 2 ) are the coordinates of the particle in the second image.

[0074] As shown in Tables 1 and 2, the movement speed of quartz sand is calculated according to the coordinates of quartz sand in different frame images, and the movement speed of microplastics is calculated according to the coordinates of microplastics in different frame images.

[0075] Table 1: Statistical results of quartz sand movement speed experiment

[0076]

[0077]

[0078] Table 2: Statistical results of microplastic movement speed experiment

[0079]

[0080]

[0081] As shown in Tables 3 and 4, by comparing the velocities of microplastics and quartz sand in the images, the velocity probability distribution of quartz sand and microplastics and the movement characteristics of microplastics and quartz sand were obtained. The movement states of microplastics and quartz sand are different.

[0082] Table 3: Comparison of probability distribution of quartz sand and microplastics velocity

[0083] Speed (m / s) Microplastics Quartz sand <1 0.285311 0.187332 1-2 0.228814 0.309973 2-3 0.155367 0.196765 3-4 0.090395 0.128032 4-5 0.084746 0.055256 5-6 0.084746 0.055256 6-7 0.039548 0.026954 6-8 0.014124 0.021563 8-9 0.011299 0.010782 9-10 0.002825 0.006739 >11 0.002825 0.001348

[0084] Table 4: Comparison of movement characteristics of quartz sand and microplastics

[0085]

Claims

1. A device for simultaneously measuring the movement of particles of two materials in a wind-blown sand flow, characterized in that: include: A wind-sand flow simulation unit and a measurement unit arranged on the side thereof; The wind and sand flow simulation unit is a square tube-shaped transparent shell with a hair dryer connected to one end. A screen plate and a rough element are arranged in sequence inside the shell along the wind direction. The screen plate is a square plate body, and its four sides are sealed to the inner wall of the shell. The rough element is fixed to the inner surface of the bottom layer of the shell. The inner surface area of ​​the bottom layer of the shell behind the rough element is the particle placement area. The measuring unit includes a synchronous controller, a laser emitting subunit, two cameras and a computer; the two cameras are arranged side by side and face the tail end of the particle placement area of ​​the shell, and a fluorescent filter is arranged on any camera; the laser emitting subunit and the two cameras are electrically connected to the synchronous controller, and the synchronous controller is electrically connected to the computer, and the laser irradiation center of the laser emitting subunit and the focusing points of the two cameras are in the same plane.

2. The device for simultaneously measuring the movement law of particles of two materials in a wind-blown sand flow according to claim 1, characterized in that: The laser emitting subunit includes a dual-pulse laser, a light guide arm and a laser emitting component. The two ends of the light guide arm are respectively connected to the dual-pulse laser and the laser emitting component. The laser emitting component is arranged above the tail end of the particle placement area. The laser surface formed by the light beam emitted by the laser emitting component is parallel to the wind direction of the fan.

3. The device for simultaneously measuring the movement law of particles of two materials in a wind-blown sand flow according to claim 1, characterized in that: An anemometer is also arranged on the inner wall of the shell.

4. The device for simultaneously measuring the movement law of particles of two materials in a wind-blown sand flow according to claim 1, characterized in that: The two cameras were placed 2-3 cm apart.

5. The device for simultaneously measuring the movement law of particles of two materials in a wind-sand flow according to claim 1, characterized in that: The laser wavelength and filter used by the laser emission subunit are matched with the dye used for dyeing particles.

6. A method for simultaneously measuring the movement of particles of two materials in a wind-blown sand flow, characterized in that: The steps include: S1. A device for simultaneously measuring the movement law of particles of two materials in a wind-sand flow as described in any one of claims 1 to 5 is provided; particles of two materials to be measured are laid in a particle placement area, wherein particles of one material to be measured are dyed particles; S2. Calibrate the cameras using a ruler so that the two cameras have overlapping fields of view, and determine the positions of the overlapping fields of view in the images captured by the two cameras; S3. Adjust the time interval between two adjacent frames according to the wind speed; S4. Turn on the fan, and the computer sends a start signal to the laser emission subunit and the camera through the synchronous controller; the laser emission subunit emits lasers, and the two cameras take motion images of the particles and send the motion images to the computer; S5. measuring the coordinates of particles of the two materials to be tested according to the particle motion images captured by the two cameras and the coordinates of the overlapping fields of view; S6. Determine the movement speed of the particles of the dyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images; determine the movement speed of the undyed particles of the undyed material to be tested based on the coordinates of the particles of the dyed material to be tested on two adjacent frames of images and the time interval between the two adjacent frames of images.

7. The method for simultaneously measuring the movement law of particles of two materials in a wind-sand flow according to claim 6, characterized in that: The specific method of determining the overlapping field of view position in step S2 is: S2-1. Fix the ruler vertically on the bottom surface of the tail end of the particle placement area in the shell; S2-2. Adjust the two cameras to the same focal length; take pictures with the two cameras respectively, and determine the coordinates of the ruler according to the images taken by the two cameras; S2-3. Determine the length of the overlapping field of view according to the horizontal coordinate of the ruler on the two images, and determine the height of the overlapping field of view according to the vertical coordinate of the ruler on the two images; S2-4. Determine the positions of the overlapping fields of view in the images captured by the two cameras according to the length and height of the overlapping fields of view.

8. The method for simultaneously measuring the movement law of particles of two materials in a wind-blown sand flow according to claim 6, characterized in that: The specific method of determining the particle coordinates of the two materials to be tested in step S5 is: S5-1. Establishing coordinate systems for the images captured by the two cameras respectively; calculating the coordinate relationship between the images captured by the two cameras according to the overlapping fields of view at the positions of the images captured by the two cameras; S5-2. Determine the coordinates of the particles according to the image captured by the camera with the filter; S5-3. Determine the coordinates of the particles of the dyed material to be tested in the image taken by the camera without a filter according to the coordinate relationship and the coordinates of the particles in the overlapping field of view in the image taken by the camera with a filter; S5-4. Based on the coordinates of all particles in the overlapping field of view in the image taken by the camera with a filter, the coordinates of the stained particles taken by the camera without a filter are eliminated, and the coordinates of the remaining particles are the coordinates of the unstained particles being measured.

Images