CN113899916B - A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera - Google Patents
A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera Download PDFInfo
- Publication number
- CN113899916B CN113899916B CN202111320062.7A CN202111320062A CN113899916B CN 113899916 B CN113899916 B CN 113899916B CN 202111320062 A CN202111320062 A CN 202111320062A CN 113899916 B CN113899916 B CN 113899916B
- Authority
- CN
- China
- Prior art keywords
- particle
- light source
- frame rate
- holographic
- camera
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000002245 particle Substances 0.000 title claims abstract description 135
- 238000000691 measurement method Methods 0.000 title claims abstract description 11
- 238000005259 measurement Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 21
- 238000001914 filtration Methods 0.000 claims abstract description 14
- 238000004364 calculation method Methods 0.000 claims description 4
- 230000011218 segmentation Effects 0.000 abstract description 2
- 238000001514 detection method Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 238000012545 processing Methods 0.000 description 5
- 238000000827 velocimetry Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 238000003745 diagnosis Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000000917 particle-image velocimetry Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/26—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H2001/0033—Adaptation of holography to specific applications in hologrammetry for measuring or analysing
- G03H2001/0038—Adaptation of holography to specific applications in hologrammetry for measuring or analysing analogue or digital holobjects
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Aviation & Aerospace Engineering (AREA)
- Computing Systems (AREA)
- Theoretical Computer Science (AREA)
- Holo Graphy (AREA)
Abstract
The invention discloses a holographic particle velocity measurement method adopting a continuous light source and a low frame rate single camera, wherein light beams emitted by the continuous light source are filtered, expanded, collimated and formed into parallel light, and the parallel light is segmented; the method comprises the steps of measuring particles, continuously recording two or more frames of particle holograms by a low-frame rate camera through segmented parallel light, reconstructing the holograms to obtain three-dimensional positions of the particles, calculating actual positions of the particles, and obtaining three-dimensional speeds of the particles by using a particle matching algorithm. The invention also discloses a holographic particle velocity measurement device, which comprises a continuous light source, a filtering, beam expanding and collimating system, a reflecting mirror and a low-frame-rate camera, wherein light beams emitted by the continuous light source form parallel light through the filtering, beam expanding and collimating system, the parallel light is segmented by the reflecting mirror and then irradiates to moving particles, and the camera records continuous multi-frame particle holograms. The measuring system adopted by the method and the device has the advantages of simple structure, low cost and easy realization, and the speed measuring upper limit is greatly improved by a parallel light segmentation mode and the adjustable performance is strong.
Description
Technical Field
The invention relates to the field of multiphase flow measurement, in particular to a holographic particle velocity measurement method and device adopting a continuous light source and a low-frame-rate single camera.
Background
In many fields of industrial production and scientific research, multiphase flow is a widely existing physical process, and effective measurement of particle parameters in the multiphase flow is an important basis for in-depth understanding of flow process mechanisms, solving scientific problems and optimizing production.
The particle velocity measurement method in multiphase flow mainly comprises laser Doppler velocity measurement, particle image velocity measurement, a spatial filtering method, an electrostatic method, a multi-exposure, long exposure and multi-frame shooting imaging method of a high-speed camera, and the like. Classical Doppler velocimetry is widely applied in the field of flow field diagnosis, but is limited to single-point measurement, and is currently limited to laboratory environments due to complex systems, expensive equipment, difficult field arrangement and the like, so that the method is extremely difficult to apply to industrial online measurement. The particle image velocimetry technology is also widely applied to flow field diagnosis due to the characteristics of full field, non-contact, planar two-dimensional, transient state, high precision and the like, and is difficult to apply to industrial sites due to the fact that the particle image velocimetry technology is high in price, complex in equipment and the like. The spatial filtering method is easy to be interfered by other factors due to the determination of the frequency peak value, and the measurement accuracy is difficult to be ensured. The average particle velocity is generally measured by electrostatic methods, and the velocity of individual particles in the flow field cannot be obtained. Imaging methods such as multi-exposure, long exposure, multi-needle shooting and the like have higher requirements on the performance of a light source or a camera, for example, pulse laser or a high-speed camera is needed, the cost is higher, and the problem that the measured particles adhere to an optical window to influence the measurement is easily caused in practical application.
The digital hologram technology is a three-dimensional measurement technology, and can conveniently record and store holograms by adopting digital recording and digital reconstruction. The measurement of the particle field by the digital holographic technology is to measure each particle in the particle field, and the motion information, the geometric information and the position information of each particle can be obtained. The Chinese patent publication No. CN109297874A discloses a holographic real-time measurement method for measuring the particle size of moving particles, which comprises the steps of generating sheet laser by a sheet laser beam expanding system and irradiating the sheet laser beam to the moving particles, forming object light by scattered light of the sheet laser beam passing through the particles, forming one-dimensional holographic fringes by interference of the object light without the sheet laser beam passing through the particles and the reference light, recording, reconstructing a hologram formed by the recorded one-dimensional holographic fringes to obtain a particle image, and calculating the particle size according to the number and the size of pixels in the particle image.
At present, a high-speed camera and a pulse light source are generally adopted for speed measurement by adopting a holographic technology, so that the measurement cost is high, and the system is complex. The device for detecting and measuring the particle size of the atmospheric cloud and fog field particles is disclosed in China patent publication No. CN212410375U, and comprises a laser beam-expanding parallel system, a particle detection and holographic shooting system, a control and data processing system and a control and data processing system, wherein the laser beam-expanding parallel system generates parallel beams to irradiate a particle detection area, when particles exist, the particles generate particle scattered light, the particle detection and holographic shooting system comprises a digital camera, the particle detection and holographic shooting system is used for judging whether particles exist in the particle detection area, when particles exist, a part of the particle scattered light enters the digital camera and records particle holograms in the particle detection area under the control of the control and data processing system, the control and data processing system comprises a photoelectric detector, the other part of the particle scattered light triggers the photoelectric detector to generate pulse trigger signals, and the control and data processing system uses the pulse trigger signals generated by the photoelectric detector to control the digital camera to shoot the particle holograms, and reconstruct and process the particle size to obtain the particle size. In addition, holographic systems employing a common continuous light source and a low frame rate camera are limited by the extremely limited frame rate speed measurement, which is often used for near static particle fields, such as particle measurements dispersed in solution.
Disclosure of Invention
The invention aims to provide a holographic particle velocity measurement method and device adopting a continuous light source and a low-frame-rate single camera, which greatly improve the upper limit of velocity measurement by segmenting parallel light beams and solve the problem that a common holographic system adopting the continuous light source and the low-frame-rate single camera can only measure particles with extremely low motion velocity.
The invention provides the following technical scheme:
a holographic particle velocimetry method employing a continuous light source and a low frame rate single camera, the method comprising the steps of:
(1) The method comprises the steps that light beams emitted by a continuous light source are subjected to filtering, beam expansion and collimation to form parallel light, the parallel light is segmented, and the number of the segments is n, wherein n is more than 1;
(2) The measured particles pass through the segmented parallel light, and a low-frame rate camera continuously records two or more frames of particle holograms;
(3) Reconstructing the hologram to obtain the three-dimensional position of the particles, calculating the actual position of the particles, and obtaining the three-dimensional speed of the particles by using a particle matching algorithm.
In the step (3), the reconstruction method is a wavelet reconstruction algorithm, the three-dimensional position of the particles obtained by reconstruction is (x h,yh,zh), the actual position of the particles in the system coordinates is calculated again (x r,yr,zr) by combining the serial number n of the beam segments where the particles are positioned, the particle matching algorithm is the nearest neighbor method, and the origin of the camera target surface is the origin of the system coordinates.
The calculation formula of the beam segment sequence number n is as follows:
Wherein 'ceil' is a downward rounding function, one section of the length of the incident light to the camera target surface is l 0, the other sections of the length are l, and the distance between two adjacent sections is h;
The actual position (x r,yr,zr) of the particle in the system coordinates is calculated as:
xr＝xh
yr＝(n-1)h+yh
the particle speed calculating method comprises the following steps:
Where (u x,uy,uz) the three-dimensional velocity of the particle, δt is the inter-frame time interval, (x i,yi,zi) the actual position of the particle in one frame, (x j,yj,zj) the actual position of the matching particle in the following frame.
The invention also provides a holographic particle velocity measurement device adopting the continuous light source and the low-frame-rate single camera, the holographic particle velocity measurement device comprises the continuous light source, a filtering beam expanding and collimating system, a reflecting mirror and the low-frame-rate camera, wherein light beams emitted by the continuous light source form parallel light through the filtering beam expanding and collimating system, the parallel light irradiates moving particles after being segmented by the reflecting mirror, and the low-frame-rate camera records continuous multi-frame particle holograms.
The filtering, beam expanding and collimating system comprises an objective lens, a pinhole and a lens.
The continuous light source can be a visible light source with the wavelength of 400nm to 700nm, and is a laser or a laser diode.
The low frame rate camera is a common industrial camera, the frame rate f is less than or equal to 100 frames per second, and the target surface size is W multiplied by H.
The reflecting mirror is a reflecting prism.
The holographic particle speed measuring device adopts a coaxial holographic system. I.e. the object light and the reference light travel in the same direction.
Typically, the particle flow velocity is predominantly in one direction, while the velocities in the other two directions are relatively small. The holographic particle velocity measurement method adopting the continuous light source and the low frame rate single camera provided by the invention has the following upper limit of velocity measurement in each direction:
ux,max=W·f
uy,max=[(n-1)h+H]·f
uz,max=L·f
where L is the range of the particle field in the z-axis. The above formula shows that the measurement method provided by the invention can greatly improve the upper limit of the measurement of the y-direction speed.
The invention mainly solves the problems of complex system and high cost of the conventional particle velocity holographic measurement method, and solves the problem that a common holographic system adopting a continuous light source and a low-frame-rate camera can only measure particles with extremely low motion velocity. The upper speed measurement limit is greatly increased by segmenting the parallel light beams.
The invention has the advantages that 1, the invention uses continuous laser and a common low-frame rate camera, the measuring system has simple structure, low cost and easy realization, 2, the invention provides a parallel light segmentation mode to greatly improve the upper limit of speed measurement, has strong adjustable performance and can change the number of parallel light segments of the system according to actual measurement requirements.
Drawings
FIG. 1 is a schematic diagram of a holographic particle velocity measurement apparatus according to the present invention;
FIG. 2 is a schematic diagram of another holographic particle velocity measurement apparatus according to the present invention;
FIG. 3 is a first frame particle hologram recorded by a camera in an embodiment;
FIG. 4 is a second frame particle hologram recorded by a camera in an embodiment;
The device comprises a continuous light source 1, a filtering beam expanding and collimating system 2, parallel light 3, parallel light 4, a measuring area 5, particles of the previous frame 6, a reflecting mirror 7, particles of the next frame 8 and a low-frame-rate camera.
Detailed Description
The following describes the embodiments of the present invention further with reference to the drawings.
Example 1
As shown in fig. 1, a holographic particle velocimetry device adopting a continuous light source and a low frame rate single camera is provided, a light beam emitted by the continuous light source1 forms parallel light 3 through a filtering, beam expanding and collimating system 2, the parallel light 3 irradiates particles in a measuring area 4, and the particles in the measuring area 4 are irradiated again after being reflected by two reflectors 6. The low frame rate camera 8 records holograms of the previous frame of particles 5 and the next frame of particles 7, respectively.
Specifically, in the present embodiment, the continuous light source 1 employs a semiconductor continuous laser having a wavelength of 532 nm. The frame rate of the low frame rate camera 8 is 100fps and the time interval δt between two frames is 0.01s. The camera resolution is 2048×2045, and the pixel size is 5 micrometers, so that the camera target surface size is 10.24mm×10.24mm. The measuring area width was 40mm. In this embodiment, the number of parallel light segments n is 2, where a length l 0 of a segment incident on the target surface of the camera is 60mm, and the distance h between two adjacent segments is 20mm.
The three-dimensional speed measurement upper limit of the device can be calculated to be u x,max＝1.024m/s,uy,max＝3.024m/s,uz,max = 4m/s, and the speed measurement upper limit in the y direction is improved by nearly 3 times.
Fig. 3 is a first frame of particle holograms recorded by a camera, and the first frame of particle holograms are reconstructed to obtain three-dimensional position coordinates (x h＝4.107mm,yh＝4.107mm,zh =120 mm) of particles, and the calculation formula is calculated according to a beam segment sequence number n:
It is available in the second parallel light segment, i.e. n=2. Calculating a formula according to the actual position of the particles in the system coordinates:
xr＝xh
yr＝(n-1)h+yh
The actual three-dimensional position of the particles was obtained as (x r1＝4.107mm,yr1＝24.107mm,zr1 = 20 mm).
Similarly, fig. 4 is a second frame of particle holograms recorded by a camera, and the second frame of particle holograms are reconstructed to obtain three-dimensional position coordinates (x h＝7.110mm,yh＝6.109mm,zh =40 mm) of particles, and the three-dimensional position coordinates are located in the first parallel light segment, and the actual three-dimensional position of the particles is (x r2＝7.110mm,yr2＝6.109mm,zr2 =40 mm).
According to the three-dimensional speed calculation formula of the particles:
the three-dimensional velocity of the particles was obtained as (u x＝0.3m/s,uy＝1.8m/s,uz =2.0 m/s).
Example 2
As shown in fig. 2, a holographic particle velocity measuring device adopting a continuous light source and a low frame rate single camera is provided, a light beam emitted by the continuous light source 1 forms parallel light 3 through a filtering, beam expanding and collimating system 2, the parallel light 3 irradiates particles in a measuring area 4, then irradiates the particles in the measuring area 4 again after being reflected by two reflectors 6, and irradiates the measuring area 4 twice after being reflected for 4 times. The low frame rate camera 8 records holograms of the previous frame of particles 5 and the next frame of particles 7, respectively. The number of parallel light segments n in this embodiment is 4.
The method of measuring particle velocity using the holographic particle velocimetry apparatus of this example was as in example 1.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111320062.7A CN113899916B (en) | 2021-11-09 | 2021-11-09 | A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111320062.7A CN113899916B (en) | 2021-11-09 | 2021-11-09 | A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113899916A CN113899916A (en) | 2022-01-07 |
| CN113899916B true CN113899916B (en) | 2025-03-14 |
Family
ID=79193707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111320062.7A Active CN113899916B (en) | 2021-11-09 | 2021-11-09 | A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113899916B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN216956085U (en) * | 2021-11-09 | 2022-07-12 | 浙江浙能长兴发电有限公司 | A Holographic Particle Velocity Measurement Device Using Continuous Light Source and Low Frame Rate Single Camera |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1172712A1 (en) * | 2000-07-14 | 2002-01-16 | Universite Libre De Bruxelles | Method for measuring the velocity of particles in a fluid medium in motion |
| CA2564764C (en) * | 2005-10-25 | 2014-05-13 | Jds Uniphase Corporation | Patterned optical structures with enhanced security feature |
| WO2017149064A1 (en) * | 2016-03-02 | 2017-09-08 | Seereal Technologies S.A. | Illumination device |
| CN111579441A (en) * | 2020-06-05 | 2020-08-25 | 浙江大学 | A digital holographic particle measuring device and method based on aperture space modulation |
-
2021
- 2021-11-09 CN CN202111320062.7A patent/CN113899916B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN216956085U (en) * | 2021-11-09 | 2022-07-12 | 浙江浙能长兴发电有限公司 | A Holographic Particle Velocity Measurement Device Using Continuous Light Source and Low Frame Rate Single Camera |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113899916A (en) | 2022-01-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Novara et al. | Multi-exposed recordings for 3D Lagrangian particle tracking with multi-pulse Shake-The-Box | |
| Hinsch | Three-dimensional particle velocimetry | |
| Scarano | Tomographic PIV: principles and practice | |
| CN102109454B (en) | Device for synchronously measuring granularity of dynamic light scattering nanometer particles of multi-particles and method thereof | |
| CN104698219B (en) | A kind of flowing two-dimension speed field measurement device and method based on near-field scattering | |
| US20150177065A1 (en) | One-dimensional global rainbow measurement device and measurement method | |
| CN105974430B (en) | Motion Object Tracking System and tracking based on random medium surface scattering light | |
| TW201120687A (en) | Method and system for positioning by using optical speckle | |
| CN102121817A (en) | Compact digital holographic apparatus and method of particle field | |
| Wu et al. | 3D boundary line measurement of irregular particle with digital holography | |
| CN103712569B (en) | Based on single image fast phase shift system and the method for detecting phases of deflection angle | |
| US9411146B2 (en) | Observation device | |
| JP2004020385A (en) | System for measuring time-serial fluid velocity in plane and space | |
| CN109781032A (en) | Optical Free-form Surface Interferometric Measurement Device and Measurement Method Based on Cascade Adaptive Optics | |
| CN113899525B (en) | Compressible Reynolds stress measurement system based on combined schlieren technology | |
| CN102494614B (en) | A high-precision digital speckle correlation measurement method | |
| CN109579747A (en) | Scattered reflection type surface topography measuring method based on two-dimension optical dot matrix | |
| CN216956085U (en) | A Holographic Particle Velocity Measurement Device Using Continuous Light Source and Low Frame Rate Single Camera | |
| CN113899916B (en) | A holographic particle velocity measurement method and device using a continuous light source and a low frame rate single camera | |
| Willert et al. | Dynamic wall shear stress measurement using event-based 3d particle tracking | |
| CN104296679A (en) | Mirror image type three-dimensional information acquisition device and method | |
| CN103211588B (en) | Blood flow velocity imaging method based on transverse velocity model | |
| Ukai | The principle and characteristics of an image fibre Background Oriented Schlieren (Fibre BOS) technique for time-resolved three-dimensional unsteady density measurements | |
| KR101019173B1 (en) | Large area non-distortion imaging device for optical speckles and method thereof | |
| Hinsch et al. | Three-dimensional particle velocimetry |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |