River image flow measurement method based on tracer particle automatic release system

Abstract

The application discloses a river image flow measurement method based on a tracer particle automatic delivery system. The tracer particle designed by the application fully considers the requirements of optical characteristics, environmental protection and applicability, and can significantly improve the particle imaging effect. The tracer particle automatic delivery system designed by the application can realize automatic delivery on the river bottom and the river surface, can automatically deliver particles for the image flow measurement methods such as the up-floating deep flow measurement and the surface flow velocity and flow field measurement, and can significantly improve the automation and intelligent level of the river image flow measurement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of river flow monitoring, and particularly relates to a river image flow measurement method based on a tracer particle automatic launching system. BACKGROUND

[0002] River flow velocity measurement plays a fundamental and strategic important role in water conservancy engineering, water environment management, flood control and disaster reduction, etc. In terms of supporting water resources management and regulation, flow velocity combined with water level data can calculate river flow, which is the basis for water resources accounting, and provides accurate data support for watershed water regulation, reservoir regulation, water right allocation, and data basis for determining river ecological flow and maintaining ecological system health. In terms of ensuring flood control safety, flow measurement during flood period can master flow velocity variation, flood peak arrival time and flow capacity.

[0003] Image flow measurement technology has the following significant advantages compared with traditional flow measurement methods (such as flow velocity meter, ADCP, flow weir tank, etc.): non-contact, the device is erected on the shore or in the air, without disturbing the water body and interfering with the flow field; high operability, suitable for flood period, rapid flow, dangerous area, etc., and has been widely used in river measurement.

[0004] In river image flow measurement, tracer particles are crucial. Image flow measurement is essentially to calculate flow velocity by tracking water flow characteristics. The launching of tracer particles can artificially enhance water surface texture or features, making flow trajectory clear and visible, thereby improving algorithm recognition and tracking accuracy. In actual scenarios, natural water surface often lacks identifiable texture (such as clear water, overcast, strong light reflection, etc.), which will seriously affect the measurement accuracy. The commonly used tracer method is to manually scatter paper, foam balls, wood chips, plastic sheets, etc. into the water body, which cannot realize automatic launching, and the recognition effect needs to be improved. SUMMARY

[0005] The technical problem to be solved by the application is to provide a tracer particle automatic launching system.

[0006] The technical problem to be solved by the application is to provide a tracer particle automatic launching system.

[0007] Technical solution: In order to solve the above technical problems, the present application provides a kind of tracer particle automatic delivery system, the tracer particle automatic delivery system includes ball bin system and control system, the ball bin system includes ball bin and several tracer particles placed in it, the control system includes drive system and the upper end opening of the ball bin connected with it, the ball bin includes ball bin bottom plate, ball groove and flange cover plate, the inner wall of the ball bin bottom plate is equipped with first lug, the ball groove is equipped with ball groove and second lug on the ball groove, the ball groove is rotated relative to the ball bin under the drive of the drive system, the flange cover plate is equipped with hose interface, the hose interface is connected with hose, the position of the hose interface is correspondingly set with the first lug, when the tracer particle falls into the ball groove, the drive system drives the ball groove to rotate, when the ball groove rotates to the corresponding position of the first lug, the first lug will push the tracer particle to the direction of hose interface, when the ball groove continues to rotate to the corresponding position of the second lug and the tracer particle, the second lug will push the tracer particle out of the hose interface, by then, the tracer particle is pushed out of the hose interface to realize the automatic delivery of tracer particle.

[0008] Wherein, the ball bin is upper down round bin structure, the ball bin is further provided with supporting leg below.

[0009] Wherein, the drive system realizes the automatic delivery of several tracer particles by the control of rotation number.

[0010] Wherein, the drive system includes stepper motor and speed reducer. With the increase of the number of ball bodies in the hose, the number of extruded ball bodies will also increase, so a speed reducer is installed at the output shaft end of the stepper motor to increase the extrusion force. Further, the rotation number of the stepper motor is accurately controlled, so as to realize the purpose of automatic ball throwing. The hose can also rotate on the water surface, and the ball bodies are directly extruded to the water surface as tracer particles for surface image flow measurement. The diameter of the tracer particle, i.e. ball body, is about 3cm, and the material is water-entering and floating. The size of the ball bin can be adjusted and designed according to the number of required ball bodies. The round bin structure below the ball bin is convenient for the ball bodies to automatically fall into the ball bin due to gravity. The ball groove is installed inside the ball bin and is rotated in the ball bin by the stepper motor. The effect is that one ball body is extruded into the hose interface for each rotation of the ball groove.

[0011] The present application also includes a river image flow measurement method based on the tracer particle automatic delivery system, which includes the following steps:

[0012] (1) Place the tracer particle automatic delivery system on the bank of the river where the river flow rate needs to be measured or on the bridge above the river;

[0013] (2) the hose is placed on the surface, middle or bottom of the river where the flow velocity is needed to be measured, and the driving device is started, the tracer particles in the hose are extruded one by one with the increase of the number;

[0014] (3) the tracer particles move with the water flow, the image of the tracer particles moving on the surface of the water flow is shot by the camera, then two color particle images are captured by the computer at a time interval of ;

[0015] (4) the characteristic color RGB value of the tracer particles is represented as (Rp, Gp, Bp), the RGB value of the pixel points in the image is represented as (Ri, Gi, Bi), according to the difference between the color of the tracer particles and the color of the water flow background, the RGB difference value between the two is calculated ;

[0016] (5) the RGB difference threshold T is set, and the tracer particle image is binarized by the following formula, wherein G is the gray value of the pixel points in the tracer particle image: ;

[0017] (6) after the two-frame tracer particle images are binarized, the morphological processing of erosion and expansion is carried out, then the region is marked, and the center position of the tracer particles in the image is calculated (Ip, Jp), according to the position of the camera and the height of the water surface, the relationship between the image horizontal and vertical coordinates and the actual horizontal and vertical coordinates on the site is calibrated, and the image center position horizontal and vertical coordinates (Ip, Jp) of the tracer particles are converted into the actual horizontal and vertical coordinates (Xp, Yp) on the site;

[0018] (7) the actual coordinates of the tracer particles in the two-frame particle images are (Xp1, Yp1) and (Xp2, Yp2) respectively, then the flow velocity at the position of each particle can be represented as: ; Vx and Vy represent the flow velocity components in the x and y directions.

[0019] The tracer particle is a standard spherical shape and has a material density less than water, and the surface of the sphere is coated with a reflective water-based environmentally friendly paint.

[0020] The material is wood, and the water-based environmentally friendly paint is red, yellow or blue water-based environmentally friendly paint.

[0021] The river includes a plain river or a mountain river.

[0022] The camera is installed on a bridge 6-8 meters above the river surface, and the camera resolution is more than 12 million pixels.

[0023] The method realizes full-automatic image flow measurement by automatically throwing tracer particles at different positions of the river and automatically measuring the flow velocity and direction of the positions where the tracer particles are located.

[0024] The working principle of the present application is as follows: the present application realizes the river image flow measurement method through the tracer particles and the automatic throwing system thereof. When the ball (tracer particle) in the upper ball bin system falls into the ball rolling groove of the ball rolling wheel due to the self-weight, the ball is rolled to the direction of the hose interface by the first protrusion as the ball rolling wheel is driven to rotate by the stepping motor. When the ball approaches the hose interface, the ball is squeezed into the hose on the right side due to the eccentric guiding effect of the second protrusion. That is, one ball is squeezed into the hose interface every time the ball rolling wheel rotates one circle. In this way, the balls in the hose are squeezed out of the hose one by one as the number of the balls increases. If the hose is placed in the river bottom, the balls are squeezed out of the hose and float to the water surface, serving as the tracer particles for the up-floating depth flow measurement. The hose can also be rotated on the water surface, and the balls are directly squeezed out to the water surface, serving as the tracer particles for the surface image flow measurement. As the number of the balls in the hose increases, the number of the squeezed balls also increases. Therefore, a speed reducer is installed at the output shaft end of the stepping motor to increase the squeezing force. Then, the accurate rotation circle number of the stepping motor is controlled, and the purpose of automatic ball throwing is achieved. Figure 3 The balls in the hose are squeezed out of the hose one by one as the number of the balls increases. If the hose is placed in the river bottom, the balls are squeezed out of the hose and float to the water surface, serving as the tracer particles for the up-floating depth flow measurement. The hose can also be rotated on the water surface, and the balls are directly squeezed out to the water surface, serving as the tracer particles for the surface image flow measurement. As the number of the balls in the hose increases, the number of the squeezed balls also increases. Therefore, a speed reducer is installed at the output shaft end of the stepping motor to increase the squeezing force. Then, the accurate rotation circle number of the stepping motor is controlled, and the purpose of automatic ball throwing is achieved.

[0025] Advantages: Compared with the prior art, the present application has the following advantages: the tracer particles designed in the present application fully consider the optical characteristics, environmental protection and applicability, and can significantly improve the particle imaging effect. The flow measurement method of the tracer particle automatic throwing system designed in the present application can realize the automatic throwing in the river bottom and the river surface, and can automatically throw particles for the up-floating depth flow measurement and the surface flow velocity and flow field measurement, which can significantly improve the automation and intelligent level of the river image flow measurement. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 FIG. 1 is a schematic diagram of the control system;

[0027] Figure 2 FIG. 4 is a front sectional view of the tracer particle automatic throwing system;

[0028] Figure 3 FIG. 5 is a side sectional view of the tracer particle automatic throwing system; 1-tracer particle, 2-ball bin, 3-leg, 4-ball rolling wheel, 5-ball rolling bin, 6-flange cover plate, 7-hose interface, 8-hose, 9-stepping motor, 10-speed reducer, 11-ball rolling groove, 12-first protrusion, 13-second protrusion. DETAILED DESCRIPTION

[0029] The application will be further described in the following specific examples. It should be pointed out that for those skilled in the art, without departing from the principles of the application, a number of variations and improvements can be made, which should also be considered as belonging to the protection scope of the application.

[0030] Example 1 Measurement of flow velocity of a plain river

[0031] 1. Construction of the tracer particle automatic releasing system

[0032] As Figures 1-3, first, build the control system, the control system includes the driving system and the upper end opening's ball bin 5 connected with it, the driving system includes the step motor 9 and the speed reducer 10 constitute, the ball bin 5 includes the ball bin bottom plate, the ball concave wheel 4 and the flange cover plate 6 constitute, the inner wall of the ball bin bottom plate is equipped with the first lug 12, the ball concave wheel 4 is equipped with the ball concave groove 11 and the second lug 13, the ball concave wheel 4 is driven under the driving of the driving system and rotates relative to the ball bin 5, the flange cover plate 6 is equipped with the hose interface 7, the hose interface 7 is connected with the hose 8, the hose interface 7 is correspondingly arranged with the first lug 12, when the tracer particle falls into the ball concave groove 11, the driving system drives the ball concave wheel 4 to rotate, when the ball concave groove 11 rotates to the corresponding position of the first lug 12, the first lug 12 will push the tracer particle to move to the direction of the hose interface 7, when the ball concave wheel 4 continues to rotate to the corresponding position of the second lug 13 and the tracer particle, the second lug 13 will push the tracer particle out of the hose interface 7, thus, the tracer particle is pushed out of the hose interface 7. Next, build the tracer particle automatic delivery system, the tracer particle automatic delivery system includes the ball bin system and the control system, the ball bin system includes the ball bin 2 and the tracer particle 1 placed in the ball bin 2, the ball bin 2 is the upper lower round bin type structure, the ball bin 2 is also equipped with 4 supporting legs 3 below. Considering the tracer particle followability and facilitating automatic delivery, the tracer particle is designed as a standard spherical shape, the diameter size can be adjusted according to the camera installation height, to ensure that the tracer particle in the collected image can be clearly identified. Considering the river environmental protection requirements, wooden material (density less than water) is selected. In order to improve the particle identification performance, the tracer particle is uniformly colored with water-based environmental protection paint with high differentiation degree color (such as red, yellow, blue, etc.) and good light reflection performance, and good imaging quality is ensured. The diameter of the tracer particle (hereinafter referred to as ball) in the application is about 3cm, and the material is water-soluble and floats on water. The size of the ball bin 2 can be adjusted according to the number of balls required. The round bin structure below the ball bin 2 is convenient for the ball to automatically fall into the ball bin due to its own weight. The ball bin 5 is installed directly below the ball bin 2, and the ball concave wheel 4 is installed inside and rotated by the step motor 9. The ball concave wheel 4 rotates one circle and pushes a ball into the hose interface 7 of the hose 8. The multiple balls in the upper ball bin naturally fall into the ball concave groove 11 of the ball concave wheel 4 due to their own weight. As the step motor 9 drives the ball concave wheel 4 to rotate, the ball is rolled to the direction of the hose interface 7 by the first lug 12. When it approaches the hose interface 7, the ball is guided to the Figure 3As shown on the right, the spherical roller 4 compresses a ball into the hose interface 7 with each rotation of the hose 8. This cycle continues, and the balls inside the hose are gradually expelled from the hose 8 as the number increases. If the hose 8 is placed on the riverbed, the balls will be expelled from the hose 8 and float to the surface, serving as tracer particles for surface depth measurement. The hose 8 can also rotate on the water surface, with the balls being directly expelled to the surface, serving as tracer particles for surface imaging measurement.

[0033] 2. Speed ​​measurement in plains and rivers

[0034] 1) Plain rivers usually have a gentle current, a width of about 60 meters, and an average depth of about 3 meters. A camera is installed on a bridge about 6 meters above the river surface. The camera has a resolution of 12 megapixels. The tracer particle automatic delivery system is placed on the bank. The tracer particles are automatically delivered from the bottom of the river at the middle of the cross section where the flow velocity is relatively high through the delivery pipe connected to the hose of the tracer particle automatic delivery system. The tracer particles in the hose will be squeezed out of the hose one by one as the number increases.

[0035] 2) The tracer particles follow the water flow. A camera captures images of the tracer particles moving on the water surface. Then, a computer periodically captures two frames of color particle images, with a time interval between the images. ;

[0036] 3) The color of the tracer particles is significantly different from the background color of the water flow. The characteristic color RGB values ​​of the tracer particles are represented as (Rp, Gp, Bp), and the RGB values ​​of the pixels in the image are represented as (Ri, Gi, Bi). Calculate the RGB difference D between the two. ;

[0037] 4) Set the RGB difference threshold T to 20, and perform binary segmentation on the particle image using the following formula, where G is the grayscale value of the pixel in the particle image:

[0038] ;

[0039] 5) After performing binary segmentation on the two particle images, morphological processing of erosion and dilation is performed. Then, region marking is used, and the horizontal and vertical coordinates (Ip, Jp) of the center position of each particle in the image are calculated. Based on the camera position and the height of the water surface, the relationship between the horizontal and vertical coordinates of the image and the actual horizontal and vertical coordinates on site is determined. The horizontal and vertical coordinates (Ip, Jp) of the center position of the particle in the image are converted into the actual horizontal and vertical coordinates (Xp, Yp) on site.

[0040] 6) The actual coordinates of each particle in the two particle images are (Xp1, Yp1) and (Xp2, Yp2) respectively. The velocity at each particle's location can be expressed as: Vx = Vy= ; Vx and Vy represent the flow velocity components in the x and y directions;

[0041] 7) The flow velocity and direction of the particle position are automatically measured according to the above steps, thereby realizing fully automatic image flow measurement.

[0042] Taking ADCP field flow measurement as a standard, five randomly selected measurement points are defined as measurement point 1~measurement point 5, and the measurement results are shown in Table 1.

[0043] Table 1 Comparison of flow velocity measurement values (perpendicular to the cross-sectional direction)

[0044]

[0045] Through field verification, the manual foam throwing process, including on-site production and throwing, generally takes more than 30 seconds, the tracer particle of the present application can be conveniently and quickly completed by the automatic throwing system, and the automatic throwing can be completed in not more than 3 seconds, the efficiency is significantly improved, the precision is improved by more than 1.2%, and the efficiency and precision of river image flow measurement are improved.

[0046] Example 2 Flow velocity measurement of mountainous river

[0047] The river width is about 120 meters, the average river depth is about 8 meters, the installation height of the camera is about 8 meters above the river surface on the bridge, the camera resolution is 12 million pixels, and during the flood period, due to the large flow velocity, the tracer particle automatic throwing system of example 1 is installed above the bridge through which the river flows, the tracer particle is thrown from above the river to the surface of the river through the tracer particle automatic throwing system, the same particle image velocimetry algorithm as example 1 is used to automatically obtain the surface flow velocity, the measurement value of the rotor flow velocity instrument of the field hydrological station is taken as a standard, the manual plastic sheet throwing is taken as a tracer particle for comparison, five randomly selected measurement points are defined as measurement point 1~measurement point 5, and the measurement results are shown in Table 2.

[0048] Table 2 Comparison of flow velocity measurement values (perpendicular to the cross-sectional direction)

[0049]

[0050] Through field verification, the manual plastic sheet throwing process, including on-site production and throwing, generally takes more than 45 seconds, the tracer particle of the present application can be conveniently and quickly completed by the automatic throwing system, and the automatic throwing can be completed in not more than 3 seconds, the efficiency is significantly improved, the precision is improved by more than 1.6%, and the efficiency and precision of river image flow measurement are improved.

Claims

1. A tracer particle automatic dispensing system, characterized by, The tracer particle automatic delivery system comprises a ball bin system and a control system, the ball bin system comprises a ball bin and a plurality of tracer particles placed in the ball bin, and the control system comprises a driving system and an open-top ball bin connected with the driving system, the ball bin comprises a ball bin bottom plate, a ball groove wheel and a flange cover plate, a first protrusion is arranged on the inner wall of the ball bin bottom plate, a ball groove and a second protrusion are arranged on the ball groove wheel, the ball groove wheel rotates relative to the ball bin under the driving of the driving system, a hose interface is arranged on the flange cover plate, a hose is connected at the hose interface, the hose interface is arranged in position corresponding to the first protrusion, when the tracer particle falls into the ball groove, the driving system drives the ball groove wheel to rotate, when the ball groove rotates to the corresponding position of the first protrusion, the first protrusion pushes the tracer particle to move to the direction of the hose interface, when the ball groove wheel continues to rotate to the corresponding position of the second protrusion and the tracer particle, the second protrusion pushes the tracer particle out of the hose interface, at this time, the tracer particle is pushed out of the hose interface to realize automatic delivery of the tracer particle, the driving system realizes automatic delivery of a plurality of tracer particles through control of the number of rotations, and the driving system comprises a stepping motor and a speed reduction mechanism.

2. A river image flow measurement method based on a tracer particle automatic release system, based on the tracer particle automatic release system according to claim 1, characterized by, The method comprises the following steps: (1) placing the tracer particle automatic delivery system on the bank of a river or on a bridge above the river where the flow velocity needs to be measured; (2) placing the hose on the surface, middle or bottom of the river where the flow velocity needs to be measured, starting the driving system, and the tracer particles in the hose will be pushed out one by one with the increase of the number; (3) The tracer particles follow the water flow movement, the movement image of the tracer particles on the water surface is shot by a camera, then two color particle images are captured by a computer at a fixed time interval ; (4) The characteristic color RGB value of the tracer particle is represented as (Rp, Gp, Bp), and the RGB value of the pixel point in the image is represented as (Ri, Gi, Bi). According to the difference between the color of the tracer particle and the background color of the water flow, the RGB difference between the two is calculated ; (5) Set the RGB difference threshold T, and perform binary segmentation on the tracer particle image by using the following formula, wherein G is the gray value of a pixel point in the tracer particle image: ; (6) after two-frame tracer particle images are subjected to binary segmentation, morphological processing of corrosion and expansion, and then region marking, the center position horizontal and vertical coordinates (Ip, Jp) of the tracer particle in the image are calculated, the relationship between the horizontal and vertical coordinates of the image and the actual horizontal and vertical coordinates on the site is calibrated according to the position of the camera and the height of the water surface, and the center position horizontal and vertical coordinates (Ip, Jp) of the image of the tracer particle are converted into the actual horizontal and vertical coordinates (Xp, Yp) on the site; (7) The actual coordinates of the tracer particles in two frames of particle images are (Xp1, Yp1) and (Xp2, Yp2), respectively, and the flow velocity at the position of each particle can be expressed as: ; Vx and Vy represent the flow velocity components in the x and y directions, respectively.

3. The river image flow measuring method of the tracer particle automatic releasing system according to claim 2, characterized by, The tracer particle is a standard spherical ball with a material density less than that of water, and the surface of the ball is coated with a water-based environmental protection paint with a reflective performance.

4. The river image flow measuring method of the tracer particle automatic releasing system according to claim 3, characterized by, The material is wood, and the water-based environmental protection paint is a red, yellow or blue water-based environmental protection paint.

5. The river image flow measuring method of the tracer particle automatic releasing system according to claim 3, characterized by, The method automatically measures the flow velocity and direction of the position where the tracer particle is located by automatically delivering the tracer particle at different positions of the river.

6. The river image flow measuring method of the tracer particle automatic releasing system according to claim 2, wherein The river comprises a plain river or a mountainous river.

7. The river image flow measuring method of the tracer particle automatic releasing system according to claim 2, wherein The camera is installed on a bridge with a height of 6-8 meters above the river surface, and the resolution of the camera is more than 12 million pixels.

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