CN217277669U

CN217277669U - Dynamic repose angle measuring device based on image and weighing

Info

Publication number: CN217277669U
Application number: CN202122986685.XU
Authority: CN
Inventors: 鸦明胜; 郭长皓; 徐幼林; 孙鑫
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2022-08-23
Anticipated expiration: 2031-11-29

Abstract

The utility model provides a dynamic angle of repose measuring device based on image and weighing, which comprises a particle hopper, a support frame, a light source lamp, a background support plate, a curtain, a high-speed camera, a high-precision electronic balance and a computer; wherein the support frame is arranged on the support platform; the high-precision electronic balance is arranged on the support platform and is positioned in the support frame; the particle hopper adopts a 30-degree conical hopper and is vertically arranged at a round opening at the top of the support frame; the curtain is made of black flocking cloth and is adhered to the background supporting plate; the high speed camera is facing the particle pile; wherein the computer is respectively in communication connection with the high-speed camera and the high-precision electronic balance. The utility model discloses a real-time collection image and weighing have obtained the characteristic information under the arbitrary moment of relevant angle of repose, have obtained the dynamic numerical value of angle of repose through the processing and the calculation to data, judge the state information under each constantly among the granule flow process from this.

Description

Dynamic repose angle measuring device based on image and weighing

Technical Field

The utility model relates to a granule mobility real-time detection field, concretely relates to dynamic repose angle measuring device based on image and weighing.

Background

The granules and powder are the most common raw materials and substance existing forms for production and living in human life and in the natural world. The individual particles have the property of being solid, while the underlying particle system has the property of being partially liquid, such as flowability. The particle system is summarized into a fourth substance form except solid, liquid and gas by scholars, and the complex characteristics of the particles also make the particles the object of attention and research of many scholars at home and abroad. In the flowing process, particles have complex interaction, and the particles continuously rub, collide and agglomerate with each other. The type, shape and size of the granules themselves affect the flowability of the granules, and the hopper responsible for carrying the flow of the granules also affects the flowability of the granules, so the flowability of the granules is complex and difficult to predict.

In the existing method, the angle of repose method is a commonly used particle flowability measurement method, but the method is generally only suitable for the measurement of static particles, namely, the real-time flowability of continuously flowing particles is difficult to measure, the particle stack is often not in a perfect conical shape, and if the conditions of unsmooth flow, arching and tilting occur in the flowing process, the bottom surface of the stack is often in an oval shape or other shapes, so the measurement of the angle of repose method has errors.

There are many places where improvement and repair of defects are needed in the practice of measuring the flowability of particles by the angle of repose method.

Disclosure of Invention

In order to solve the problems, the invention discloses a dynamic repose angle measuring device based on images and weighing, which can obtain a corresponding repose angle at each moment in the particle flowing process; and meanwhile, the angle of repose is optimally adjusted according to the feedback of the mass weighing, and relatively accurate particle flowability characteristics are obtained.

A dynamic repose angle measuring device based on images and weighing comprises a particle hopper, a support frame, a light source lamp, a background support plate, a curtain, a high-speed camera, a high-precision electronic balance and a computer; wherein the support frame is arranged on the support table; the high-precision electronic balance is arranged on the support platform and is positioned in the support frame; the particle hopper adopts a 30-degree conical hopper and is vertically arranged at a round opening at the top of the support frame; a background supporting plate is arranged beside one end of the supporting frame, and the wide-source lamp is arranged beside the other end of the supporting frame; wherein the background supporting plate is arranged on the supporting table; the curtain is made of black flocking cloth and is adhered to the background supporting plate; the particles in the particle hopper vertically flow out from a bottom outlet and are stacked on a high-precision electronic balance, and the high-speed camera is right opposite to the particle stack; and the computer is in communication connection with the high-speed camera and the high-precision electronic balance respectively.

The particle hopper is a common 30-degree conical hopper manufactured by 3D printing; the top of the support frame is provided with a round opening for vertically placing the particle hopper, the support frame is integrally of a cubic structure, and only the frame is reserved; the high-precision electronic balance has data reading and writing capability after being connected to a computer, and can store a weighing result; the light source adopts the LED lamp without stroboflash, the power can reach 30W, the whole test system can be illuminated, and the difference of the image collected by the high-speed camera due to stroboflash can be avoided.

The industrial high-speed camera adopts a high-speed video camera of a Lingyun photon 4M180-CL model, and adopts a lens and an acquisition card which are equipped in the series, so that the camera is just opposite to the particle stack during image acquisition;

the computer is provided with an image data acquisition module and an image processing module.

The image data acquisition module uses Sapera Cam Expert and Stream7 to set camera parameters and derive pictures, and the image processing module adopts python3.8 to carry out calculation design.

The utility model discloses a theory of operation is:

1. the particles flow in the system only by means of the self gravity of the particles without applying external force, and flow out of the particle hopper in the detection process, and finally fall on the high-precision electronic balance through the image acquisition area;

2. in the image acquisition area, a high-speed camera acquires a particle pile image on a high-precision electronic balance, the frame rate can reach more than 100fps, a light source lamp assists in improving the image acquisition quality, a stroboflash-free LED lamp can also avoid image quality difference caused by stroboflash, and a curtain made of black flocked fabric is attached to a background supporting plate, so that the imaging quality is improved;

3. the high-precision electronic balance can better weigh the mass of the particle stack in the particle flowing process, is in communication connection with a computer, and collects data and transmits the data to the computer;

4. exporting and storing the image, preprocessing the image, segmenting the image and extracting the characteristics, and extracting the outline and the height h (t) of the particle pile;

5. fitting the particle stacking contour in the image and solving the predicted value alpha of the repose angle ₁ (t)；

6. Obtaining the mass m (t) of the particle stacking material in any image according to the relation between the weighing mass and the time, obtaining the bottom surface radius r (t) of the particle stacking material according to the approximate cone processing of the particle stacking material, and obtaining the theoretical value alpha of the repose angle according to the relation between the bottom surface radius and the height ₂ (t)；

7. Taking the mean value of the predicted value and the theoretical value of the angle of repose as a final angle of repose measurement value alpha (t);

the repose angle predicted value is a repose angle value obtained by calculation after fitting a contour according to a particle pile in a two-dimensional image; the repose angle theoretical value is a repose angle value calculated by the mass and density information of particles after the particle stacking is approximately conical; the final measured value of the angle of repose is a result obtained by averaging a predicted value and a theoretical value, and is used as a result for judging the change of the particle flowability in the whole flowing process, the three values can be continuously changed along with the flowing of the particles, and the angle of repose measured by the traditional method is a static fixed value;

the preprocessing of the image comprises image decomposition, gray level transformation and filtering noise reduction, and finally a gray level image with clear particle outline is obtained; the image segmentation carries out self-set threshold segmentation according to the gray level of the image to obtain a binary image; the feature extraction extracts boundaries from the binary image and converts information in the image into actual parameters of angle of repose and windrow height.

The utility model has the advantages that: the continuous process that the high-speed camera was used to gather the granule and flows records angle of repose dynamic change process, utilizes the angle of repose that the quality estimation angle of repose reachd the image to optimize simultaneously, and the degree of integration of system is high, and the precision is high, and the operation of also being convenient for can reachd the mobility change process of granule fast.

Drawings

Fig. 1 shows an angle of repose measuring device according to the present invention;

fig. 2 is a flow of the angle of repose measuring method of the present invention;

FIG. 3 is a calculation principle after the stacking cone approximation;

list of reference numerals:

in the figure, 1-particle hopper, 2-support frame, 3-light source lamp, 4-background support plate, 5-black curtain, 6-high speed camera, 7-high precision electronic balance, 8-computer; 9-support table.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and detailed description, which will be understood as being illustrative only and not limiting in scope. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

As shown in fig. 1, in the dynamic repose angle measurement system based on image and weighing of the present embodiment, no external force is applied, and only the gravity of particles is relied on to realize the flow of particles in the system, the particles flow out of a particle hopper in the detection process, and finally fall on a high-precision electronic balance 7 through an image acquisition area;

in the image acquisition area, the high-speed camera 6 acquires the particle stockpile image on the high-precision electronic balance 7, the frame rate can reach more than 100fps, the light source lamp 3 assists in improving the image acquisition quality, the non-stroboscopic LED lamp can also avoid image quality difference caused by stroboscopic, and the background support plate 4 is attached with the curtain 5 made of black flocking cloth, so that the imaging quality is improved;

the high-precision electronic balance 7 can better weigh the mass of the particle stack in the particle flowing process, and after the flowing is finished, the mass data of the particle stack in the flowing process is imported and stored in the computer 8;

the using process of the measuring system is shown in fig. 2, and specifically comprises the following steps:

1) the system is powered on, the light source lamp 3, the high-precision electronic balance 7, the computer 8 and the high-speed camera 6 are turned on, a flow test experiment is carried out, and the parameters such as the focal length, the window resolution, the collected frame rate, the exposure time and the exposure gain of the high-speed camera are adjusted through the equipped software, so that a better particle stacking image can be obtained. Adjusting the weighing unit, the data time interval and the data format of the high-precision electronic balance 6;

2) after the software and hardware of the system are set, starting the monitoring and recording functions of the high-speed camera 6, pouring experimental particles into the particle hopper 1, and enabling the particles to flow out from an outlet at the bottom of the hopper 1 under the action of gravity and vertically fall on a supporting disc of a high-precision electronic balance 7 below;

3) with the advance of time, the particles continuously flow, the particle stockpile accumulated on the high-precision electronic balance 7 is continuously changed, the images and the quality data acquired by the high-speed camera and the high-precision electronic balance are continuously changed, the images and the quality data are kept stable until all the particles flow, and the data acquisition is stopped;

4) exporting data acquired in the particle flowing process, and respectively processing and calculating corresponding acquired images and quality data at each moment by taking time as a contrast;

5) using a computer 8 to perform Gaussian filtering on the acquired image, removing noise in the background, then performing channel decomposition on the image, decomposing the RGB image into R component images, G component images and B component images, selecting the component images with obvious color contrast between the background and the particle area, performing gray level transformation, and converting the image into a gray level image;

6) carrying out image segmentation on the preprocessed image according to a self-set threshold value mode to obtain a binary image;

7) extracting the contour of the binary image, extracting the contour, solving the predicted angle of repose of the image by adopting a method of fitting a Gaussian distribution function, and obtaining the height information of the stockpile;

8) as shown in fig. 3, the collected mass data is calculated, the volume of the stockpile at the moment is calculated according to the mass and the density, and the theoretical angle of repose of the particles can be calculated according to the volume and the height by regarding the particle stockpile approximately as a cone;

9) the predicted angle of repose is information obtained according to a two-dimensional image, three-dimensional information of particles is lacked, the theoretical angle of repose is information obtained according to cone approximation processing of stockpile, and the two angle of repose values have a complementary relation in function, so that an average value solving mode is adopted as a final angle of repose measurement value, and a dynamic angle of repose related to the whole process of particle flowing can be obtained according to time data set during image and data acquisition;

10) not only is the flowability of the particles determined overall from the dynamic angle of repose, but the flow stability at each moment during the flow of the particles is also determined.

The technical means disclosed in the scheme of the invention are not limited to the technical means disclosed in the above embodiments, but also include the technical means formed by any combination of the above technical features.

Claims

1. The utility model provides a dynamic angle of repose measuring device based on image and weighing which characterized in that: comprises a particle hopper (1), a support frame (2), a light source lamp (3), a background support plate (4), a curtain (5), a high-speed camera (6), a high-precision electronic balance (7) and a computer (8); wherein the support frame (2) is arranged on the support table (9); wherein the high-precision electronic balance (7) is arranged on the support table (9) and is positioned in the support frame (2); the particle hopper (1) adopts a 30-degree conical hopper and is vertically arranged at a round opening at the top of the support frame (2); a background supporting plate (4) is arranged beside one end of the supporting frame (2), and the light source lamp (3) is arranged beside the other end of the supporting frame; wherein the background support plate (4) is arranged on the support table (9); the curtain (5) is made of black flocking cloth and is adhered to the background supporting plate (4); the particles in the particle hopper (1) vertically flow out from a bottom outlet and are stacked on a high-precision electronic balance (7), and a high-speed camera (6) is opposite to the particle stack; wherein the computer (8) is respectively in communication connection with the high-speed camera (6) and the high-precision electronic balance (7).

2. The dynamic angle of repose measuring device based on image and weighing of claim 1, wherein: the light source lamp (3) adopts an LED lamp without stroboflash.

3. The dynamic angle of repose measuring device based on image and weighing of claim 1, wherein: the support frame (2) is of a cubic hollow frame structure.

4. The dynamic angle of repose measuring device based on image and weighing of claim 1, wherein: the upper end of the light source lamp (3) is arranged at the top of the support frame (2).