LU102721B1 - Underwater laser in situ particle imaging device and imaging method - Google Patents

Underwater laser in situ particle imaging device and imaging method Download PDF

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Publication number
LU102721B1
LU102721B1 LU102721A LU102721A LU102721B1 LU 102721 B1 LU102721 B1 LU 102721B1 LU 102721 A LU102721 A LU 102721A LU 102721 A LU102721 A LU 102721A LU 102721 B1 LU102721 B1 LU 102721B1
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LU
Luxembourg
Prior art keywords
image
water area
target water
particles
acquisition device
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Application number
LU102721A
Other languages
French (fr)
Inventor
Zixin Li
Hong Song
Zhiguo He
Xuehao Feng
Hui Huang
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Univ Zhejiang
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Priority to LU102721A priority Critical patent/LU102721B1/en
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Publication of LU102721B1 publication Critical patent/LU102721B1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N15/14Optical investigation techniques, e.g. flow cytometry
    • G01N15/1468Optical investigation techniques, e.g. flow cytometry with spatial resolution of the texture or inner structure of the particle
    • G01N15/147Optical investigation techniques, e.g. flow cytometry with spatial resolution of the texture or inner structure of the particle the analysis being performed on a sample stream
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/704Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter
    • G01F1/708Measuring the time taken to traverse a fixed distance
    • G01F1/7086Measuring the time taken to traverse a fixed distance using optical detecting arrangements
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N15/14Optical investigation techniques, e.g. flow cytometry
    • G01N15/1429Signal processing
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N15/14Optical investigation techniques, e.g. flow cytometry
    • G01N15/1429Signal processing
    • G01N15/1433Signal processing using image recognition
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/001Full-field flow measurement, e.g. determining flow velocity and direction in a whole region at the same time, flow visualisation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/18Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance
    • G01P5/20Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance using particles entrained by a fluid stream
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N2015/0042Investigating dispersion of solids
    • G01N2015/0053Investigating dispersion of solids in liquids, e.g. trouble
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N2015/1027Determining speed or velocity of a particle

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Immunology (AREA)
  • Dispersion Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Signal Processing (AREA)
  • Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)

Abstract

This invention discloses underwater laser in situ particle imaging device and imaging method, laser generator of the device is placed in target water area after being waterproofed and sealed for providing the incident light source in target water area. The image acquisition device is place in target water area after being waterproofed and sealed for acquiring the image of target water area, and storing the acquired image in memorizer or directly transmits the image to computer, and computer reads the images in memorizer or is directly connected with the image acquisition device. The invention has the advantages of acquiring the flow field conditions underwater at close range and realizing in-situ observation, and the observation angle can be increased with bracket.

Description

DESCRIPTION Underwater laser in situ particle imaging device and imaging method
TECHNICAL FIELD This invention relates to imaging device, in particular to underwater laser in situ particle imaging device and imaging method.
BACKGROUND Laser particle imaging technology can observe the flow field through particle motion, and can obtain a large number of velocity variation information at the spatial points in a instant. At the same time, it has high measurement accuracy, and it is a hot topic in current hydrodynamics measurement research, it is necessary to improve this technology.The existing laser particle imaging devices mainly have two types: vehicle-mounted type and immobilized type. The former application environment is towing tank, which is divided into two kinds: vehicle- mounted and shore-mounted, while the latter is mainly used in circulating water tanks and other small environments. Towing tank is an experimental pool that uses ship model test method to understand the performance of ships, which mainly serves the field of ships.For hydrodynamic research in other directions, it is mainly a small water tank, laser particle imaging technology applied in this kind of environment can not observe the flow field underwater at close range, which is quite inconvenient in practice. Therefore, underwater laser in-situ particle imaging device is very meaningful for such cause.
SUMMARY In view of the above shortcomings, the present invention provides an underwater laser in-situ particle imaging device and imaging method. By putting laser generator and image acquisition device into water, tracer particles motion image is shot underwater at close range, and underwater in-situ laser particles are observed in situ, thereby realizing in-situ monitoring of the downstream field.
In order to solve the above problems, the invention adopts the following technical scheme: an underwater in-situ laser particle imaging device comprises: Laser generator is placed in target water area after being waterproofed and sealed for providing the incident light source in target water area.
Image acquisition device is place in target water area after being waterproofed and sealed for acquiring the image of target water area, and storing the acquired image in memorizer or directly transmits the image to computer.
Computer reads the images in memorizer or is directly connected with the image acquisition device.
Further, image acquisition device is comprised of optical lens, CCD image sensor, video processing system which are sequentially connected, wherein, the optical lens receives images and transmits them to the CCD image sensor, and the CCD image sensor converts optical signals into electrical signals, which are further amplified by the video processing system and stored in memorizer or directly transmitted to a computer.
Further, the described memorizer is SD card.
Further, the described laser generator and the image acquisition device are sealed in a transparent box.
Further, tracer particles are arranged in the described target water area.
This invention also provides underwater laser in situ particle imaging device and imaging method which comprises the following steps: Step 1, Tracer particles are scattered in the target water area. The laser generator illuminates the target water area, and the tracer particles move with the fluid and reflect the light of the incident light source Step 2, Turning on the image acquisition device. The image acquisition device receives the light reflected by the tracer particles, obtains the imaging of the target water area, and stores the image in a memorizer or directly transmits it to computer.
Step 3, After receiving the imaging, the computer processes the image, and the specific process is as follows First, the image is enhanced to increase the contrast between tracer particles and background, and then binarized to distinguish particles from background. Identifying and locating the particles in the image by edge detection and region filling. Further, matching the identified particles. Dividing the image into small cells in pixel units, finding the position of a particle in a small cell of the first particle image in the second particle image after time interval At, hence obtaining average displacement of particles in the unit, so that the average velocity of particles in the unit can be obtained. Then carry out the same operation on other units to get the velocity vector of particles in other areas. According to the above method, the velocity distribution information, the corresponding spatial structure and flow characteristics of the target flow field can be obtained.
Compared with the prior art, the invention has the beneficial effects as follows: the compartment of laser generator and the image acquisition device are waterproofed and sealed. According to the invention, the motion images of tracer particles can be shot underwater at close range, especially in common small environments such as water tanks, so as to realize in-situ observation and solving the defect exists in the prior art that the laser particle imaging device cannot directly do underwater observation in such environments. Compared with the existing fixed particle imaging device, the invention has feature of being easy to operate and increasing observation angle.
BRIEF DESCRIPTION OF THE FIGURES Fig. 1 is a simplified model of underwater laser in-situ particle imaging system.
Fig. 2 is a detailed structural diagram of the underwater laser in-situ particle imaging system Fig. 3 is an explanatory diagram of an image processing method Wherein, Laser generator 1, Image acquisition device 2, Computer 3, tracer particles, box 5.
DESCRIPTION OF THE INVENTION The invention will be further described in detail with reference to the attached drawings and specific embodiments.
As shown in fig.1-2, the invention provides an underwater laser in-situ particle imaging device, which comprises: Laser generator 1 is placed in the target water area to provide incident light source for the target water area after being waterproofed and sealed.
Image acquisition device 2 is placed in the target water area for obtaining the image of the target water area after being waterproofed and sealed, and it acquires the image of target water area, and stores the acquired image in memorizer or directly transmits the image to computer 3. The described memorizer is SD card.
Computer 3 reads the image stored in memorizer or directly connects with image acquisition device 2.
The described image acquisition device 2 is comprised of optical lens, CCD image sensor, video processing system which are sequentially connected, wherein, the optical lens receives images and transmits them to the CCD image sensor, and the CCD image sensor converts optical signals into electrical signals, which are further amplified by the video processing system and stored in memorizer or directly transmitted to a computer 3.
The described laser generator 1 and image acquisition device 2 are both sealed in a transparent box 5 that are used to protect the laser generator 1 and image acquisition device 2, ensuring laser generator 1 and image acquisition device 2 are water-insulated to work properly, and detachable bracket is attached that can shoot the moving image of tracer particles at close range underwater and realize underwater in-situ observation.
There are tracer particles 4 in the target water area, and the tracer particles 4 are used to reflect the change of flow field.
Underwater laser in situ particle imaging device and imaging method comprises the following steps Step 1, turning on the system and laser generator 1, the image acquisition device 2 and the computer 3, placing laser generator 1, the image acquisition device 2 in the target water area, scattering tracer particles 4 in the target water area. The laser generator illuminates the target water area, and the tracer particles move with the fluid and reflect the light of the incident light source.
Step 2, turning on image acquisition device 2, image acquisition device 2 receives the light reflected by the tracer particles, obtaining the imaging of the target water area, and directly transmitting the imaging to the computer 3.
Step 3, Computer 3 processes the image after receiving the imaging, and the specific process is as follows with reference to fig.3.
First, the image is enhanced to increase the contrast between tracer particles and background, and then binarized to distinguish particles from background. Identifying and locating the particles in the image by edge detection and region filling. Further, matching the identified particles. Dividing the image into small cells in pixel units, finding the position of a particle in a small cell of the first particle image in the second particle image after time interval At, hence obtaining average displacement of particles in the unit, so that the average velocity of particles in the unit can be obtained. Then carry out the same operation on other units to get the velocity vector of particles in other areas. According to the above method, the velocity distribution information, the corresponding spatial structure and flow characteristics of the target flow field can be obtained.
The above is only the preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, without departing from the overall concept of the present invention, several changes and improvements can be made, which should also be regarded as the protection scope of the present invention.

Claims (6)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:
1. Underwater laser in situ particle imaging device is characterized in laser generator is placed in target water area after being waterproofed and sealed for providing the incident light source in target water area; the image acquisition device is place in target water area after being waterproofed and sealed for acquiring the image of target water area, and storing the acquired image in memorizer or directly transmits the image to computer, computer reads the images in memorizer or is directly connected with the image acquisition device.
2. According to claim 1, underwater laser in situ particle imaging device is characterized in that described image acquisition device is comprised of optical lens, CCD image sensor, video processing system which are sequentially connected, wherein, the optical lens receives images and transmits them to the CCD image sensor, and the CCD image sensor converts optical signals into electrical signals, which are further amplified by the video processing system and stored in memorizer or directly transmitted to a computer.
3. According to claim 1, underwater laser in situ particle imaging device is characterized in that the described memorizer is SD card.
4. According to claim 1 and claim 2, underwater laser in situ particle imaging device is characterized in that the described laser generator and the image acquisition device are sealed in a transparent box
5. According to claim 1 and claim 2, underwater laser in situ particle imaging device is characterized in that tracer particles are arranged in the target water area.
6. Underwater laser in situ particle imaging device and imaging method is characterized in comprising the following steps:
step 1: tracer particles are scattered in the target water area; the laser generator illuminates the target water area, and the tracer particles move with the fluid and reflect the light of the incident light source;
step 2: turning on the image acquisition device; the image acquisition device receives the light reflected by the tracer particles, obtains the imaging of the target water area, and stores the image in a memorizer or directly transmits it to computer;
step 3: computer processes the image after receiving the imaging, and the specific process is as follows:
first, the image is enhanced to increase the contrast between tracer particles and background, and then binarized to distinguish particles from background; identifying and locating the particles in the image by edge detection and region filling; further, matching the identified particles; dividing the image into small cells in pixel units, finding the position of a particle in a small cell of the first particle image in the second particle image after time interval At, hence obtaining average displacement of particles in the unit, so that the average velocity of particles in the unit can be obtained; then carry out the same operation on other units to get the velocity vector of particles in other areas; according to the above method, the velocity distribution information, the corresponding spatial structure and flow characteristics of the target flow field can be obtained.
LU102721A 2021-03-31 2021-03-31 Underwater laser in situ particle imaging device and imaging method LU102721B1 (en)

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LU102721A LU102721B1 (en) 2021-03-31 2021-03-31 Underwater laser in situ particle imaging device and imaging method

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LU102721A LU102721B1 (en) 2021-03-31 2021-03-31 Underwater laser in situ particle imaging device and imaging method

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Effective date: 20211011