CN-121861066-B - Identification tracking method and measurement method for particles in impact wall surface of particle swarm

CN121861066BCN 121861066 BCN121861066 BCN 121861066BCN-121861066-B

Abstract

The invention belongs to the field of micro-particle impact experiments, and particularly relates to a method for identifying and tracking particles in an impact wall of a particle swarm and a measuring method, wherein the method for identifying and tracking the particles comprises the following steps of S1, marking target particles in the particle swarm, S2, obtaining particle parameters before the target particles impact the wall of the particle swarm, S3, obtaining the spatial position, the moving speed and the incident angle of the last frame before the target particles impact the wall, S4, constructing a particle impact motion track prediction model, calculating the predicted position of the target particles in the n frame range after the target particles impact the wall, S5, constructing a judgment model, obtaining n frame images, and judging the particles in the predicted position through the judgment model. The invention can effectively solve the key problem of identity loss caused by reasons such as rebound direction, abrupt speed change, mutual shielding, visual field departure and the like of particles when the particles strike the wall surface.

Inventors

MA LIKUN
LUO JINGLONG
FENG YUNCHAO
CHEN BINBIN
XIA ZHIXUN

Assignees

中国人民解放军国防科技大学

Dates

Publication Date: 20260512
Application Date: 20250805

Claims (8)

1. The method for identifying and tracking particles in the impact wall surface of the particle swarm is characterized by comprising the following steps: S1, marking target particles in a particle group; S2, acquiring particle parameters, including particle size and sphericity, of target particles in the particle swarm before the target particles impact the wall surface; s3, acquiring the spatial position, the movement speed and the incidence angle of the last frame of the target particles before impacting the wall surface; S4, constructing a particle impact motion trail prediction model, wherein the particle impact motion trail prediction model takes the sphericity of particles, the spatial position of the last frame, the motion speed and the incidence angle as input, and calculates the predicted position of the target particles in the range of n frames after the target particles impact the wall surface; s5, constructing a judging model, acquiring n frames of images, judging particles positioned in the predicted position through the judging model, and judging that the particles are the same as the target particles before collision if the requirement of the judging model is met; the particle impact motion trail prediction model is as follows: The symmetry of particle motion tracks before and after collision and the time correlation of speed mutation on the frame number are obtained by utilizing the properties of the target particles, data association matching is carried out, and the predicted positions of the target particles in the range of n frames after the target particles strike the wall surface are output; the judgment model is as follows: The particle diameter difference between the particle diameter of the particle and the particle diameter of the target particle is within a set range, the speed difference between the particle speed and the speed of the target particle before impacting the wall surface is within a set range, and the angle difference between the incidence angle of the particle and the predicted rebound angle of the target particle is within a set range, and if the three points are met, the requirement of a judgment model is met.
2. The method for identifying and tracking particles in an impact wall of a particle swarm according to claim 1, wherein the symmetry of the motion trajectories of the particles before and after the impact is higher, and the motion trajectories of the particles before and after the impact are more symmetrical.
3. The method of claim 1, wherein the step of obtaining the particle size of the target particles in the particle group before the target particles strike the wall surface comprises: And acquiring front and rear three frames of pictures of the impact wall surface of the target particle, calculating the equivalent particle size according to the pixel area occupied by the particle identification area through an area calculation formula, and taking the average value of the six groups of particle sizes obtained through calculation as the final particle size.
4. The method of claim 1, wherein the step of obtaining the sphericity of the population of particles before the target particles strike the wall surface comprises: and acquiring front and rear three frames of pictures of the impact wall surface of the target particles, calculating equivalent sphericity according to pixels occupied by the particle identification area through a sphericity calculation formula, and taking the average value of the calculated six groups of sphericity as the final sphericity.
5. The method of claim 1, wherein the step of obtaining the movement speed of the target particle in the last frame before the impact on the wall comprises: and dividing the displacement of the geometric center particles of the identification area of the target particles of the front and rear frames by the cross-frame time.
6. The method of claim 1, wherein the step of obtaining the incidence angle of the target particle on the last frame before the impact on the wall comprises: and according to the identification, the vertical direction of the wall surface is a fixed direction, and the included angle between the incident speed and the direction is an incident angle.
7. A method for measuring particles in an impact wall of a particle swarm, comprising marking all particles in a focal plane of a camera in the particle swarm as target particles, tracking the target particles by the identification tracking method of the particles in the impact wall of the particle swarm according to any one of claims 1-6, and marking the target particles after the impact wall; recording analysis is carried out on all target particles before and after the target particles strike the wall surface.
8. The method of claim 7, further comprising initializing global parameter particle detection, shape filtering, defocus reconstruction, and pre-collision multi-particle tracking and visualization prior to the method of particle population impact wall particle measurement.

Description

Identification tracking method and measurement method for particles in impact wall surface of particle swarm Technical Field The invention belongs to the field of micro-particle impact experiments, and particularly relates to a method for identifying and tracking particles in an impact wall of a particle group and a measuring method. Background When the high-speed photographing method is used for photographing the particle targets with the micron-sized small particle size and high speed (tens of hundreds of meters per second), the parameter requirements on an observation device are high, and the morphology structure of moving particles and the dynamic behavior of a wall collision process can be clearly captured only by adopting a long-focus lens with extremely high frame frequency and large magnification, so that the resolution of image data obtained by the photographing method is low, and the visual field is extremely small (about 1 mm)2 Mm) and the focal plane is particularly narrow (tens of microns). And under the extreme jet flow working condition, the motion track path of the medium-high speed micron-sized particles impacting the wall surface is difficult to accurately control, the randomness is strong, the particles are difficult to control to the focal plane, and high-quality effective data are difficult to obtain. Therefore, in the high-speed micron-sized particle collision wall test, the flow of particles is increased, the particles are impacted on the wall surface, the probability that the particles fall on the focal plane of the long-focus lens is increased, and the test efficiency is improved. However, after the particle quantity is increased, the particles are non-spherical, the particle size is small, the speed is high, so that alignment is difficult to track, particularly, after the collision wall surface rebounds, the rebounded path and the incident path are not completely symmetrical after the particles collide with the wall due to the non-standard spherical particle group, and the speed of the particles is suddenly changed before and after collision, so that tracking, identification and losing of the particle group are easy to cause. Disclosure of Invention The invention aims to provide a high-reliability identification tracking method and a measurement method for particles in a particle group impact wall surface aiming at the conditions of non-sphericity, small particle size and high speed of particles. The invention provides a method for identifying and tracking particles in an impact wall surface of a particle swarm, which comprises the following steps: S1, marking target particles in a particle group; S2, acquiring particle parameters, including particle size and sphericity, of target particles in the particle swarm before the target particles impact the wall surface; s3, acquiring the spatial position, the movement speed and the incidence angle of the last frame of the target particles before impacting the wall surface; S4, constructing a particle impact motion trail prediction model, wherein the particle impact motion trail prediction model takes the sphericity of particles, the spatial position of the last frame, the motion speed and the incidence angle as input, and calculates the predicted position of the target particles in the range of n frames after the target particles impact the wall surface; S5, constructing a judging model, acquiring n frames of images, judging particles located in the predicted position through the judging model, and judging that the particles are the same as the target particles before collision if the requirement of the judging model is met. Further, the particle impact motion trail prediction model is as follows: And (3) obtaining the symmetry of particle motion tracks before and after collision and the time correlation of speed mutation on the frame number by utilizing the properties of the target particles, carrying out data association matching, and outputting the predicted position of the target particles within the range of n frames after the target particles strike the wall surface. Further, in the symmetry of the particle motion trajectories before and after collision, the higher the sphericity of the target particles, the more symmetrical the particle motion trajectories before and after collision. Further, the judgment model is as follows: The particle diameter difference between the particle diameter of the particle and the particle diameter of the target particle is within a set range, the speed difference between the particle speed and the speed of the target particle before impacting the wall surface is within a set range, and the angle difference between the incidence angle of the particle and the predicted rebound angle of the target particle is within a set range, and if the three points are met, the requirement of a judgment model is met. Further, the step of obtaining the particle size of the target particles in the particle group befo