CN115096768A - Backlight imaging system and method capable of simultaneously measuring particle size and volume concentration of particles - Google Patents
Backlight imaging system and method capable of simultaneously measuring particle size and volume concentration of particles Download PDFInfo
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- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
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- G01N15/0205—Investigating particle size or size distribution by optical means, e.g. by light scattering, diffraction, holography or imaging
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Abstract
The invention discloses a backlight imaging system and a backlight imaging method capable of simultaneously measuring particle size and volume concentration of particles. The system comprises a support system, an illumination system, an imaging system and a calibration system; the support system provides support for the connection and fixation of the imaging system and the illumination system; the illumination system provides a light source and transmits the light to the imaging system uniformly; the imaging system is used for acquiring the data of the particle size and the volume concentration of the opaque particles in the water body environment; the calibration system ensures the accuracy of the data acquired by the imaging system. The method comprises the following steps: s1, checking and adjusting the support system; s2, turning on the lighting system; s3, preparing imaging conditions; s4, calibrating the system; s5, data processing for identifying particles; s6, selecting focusing particle data processing; and S7, establishing a focusing parameter model and verifying. The invention provides a non-deviation volume concentration estimation aiming at the self-adaptive sampling volume changing along with the particle size; for high concentration measurements, the poisson distribution of particles is used to correct for particle overlap effects.
Description
Technical Field
The invention relates to the field of physical models and imaging systems of solid-liquid two-phase flow, in particular to a backlight imaging system and method capable of simultaneously measuring particle size and volume concentration of particles.
Background
Meanwhile, the technology for measuring the particle size and the volume concentration of various particles is of great importance to natural environment protection and industrial production safety, and is mainly applied to the fields of sediment transport and the like.
At present, various non-invasive measuring devices have been applied to the above scenes in succession and have been moderately popularized. For example, acoustic inversion measurements enable the conversion of backscatter intensity to concentration signals based on known particle sizes. Although the technology of multi-frequency particle size and concentration acquisition of an acoustic wave device has made great progress, the systematic error caused by the uncertainty of the inversion process and the need of an independent calibration flow are the non-negligible bottleneck of the acoustic inversion device. The other is measurement equipment and technology based on optical principles, including optical backscattering and transmission of infrared or visible light, laser phase doppler shift, laser diffraction and direct imaging methods. The optical device is mostly dependent on the back-scattered intensity as well as the refractive index and the transmission of the particle size. In contrast, devices based on laser means provide more reliable statistics on particle size, but are generally limited to spherical particles; direct imaging systems and methods are advantageous in measuring irregular size, shape, density, and spatial distribution of particles in stationary or steady flow systems. Direct imaging methods can be classified according to the direction of incident light (or scatter): front-lit (back-scattered), side-lit (side-scattered), and back-lit (forward-scattered). Front and side light methods need to solve the scattering problem of non-uniform light in order to estimate the particle size and shape characteristics. On the other hand, the back-light imaging method provides better contrast with black shadow images by particles under a white background. This technique is again innovative in order to obtain an accurate volume concentration, since the depth of field or the flake thickness affects the estimation of the particle concentration. In particular, using a fixed focus criterion for each particle size under the same optical conditions may result in a depth of field that increases with particle size, resulting in larger particle size errors and smaller volume concentration estimates.
To address the effect of depth of field on particle size and concentration estimation, many devices and techniques identify focused particles by using parameters such as threshold gray scale, halo width, maximum normalized contrast, diffraction fringes, empirical or critical gradient indicators, and ratio of maximum intensity gradient to average intensity gradient. However, it is not clear whether different optical conditions (e.g. light intensity, magnification), particle shape and overlap effects will affect the above-mentioned focusing parameters. In addition, the above devices and techniques are mostly suitable for two-phase liquid/gas scenarios, but have poor applicability to solid/liquid scenarios. The invention provides a system and a method capable of simultaneously measuring particle size and volume concentration based on a backlight imaging technology, which are expected to be widely applied to the related field.
Disclosure of Invention
Aiming at the defects of the existing equipment and technology, the invention provides a backlight imaging system and method for simultaneously measuring the particle size and the volume concentration of opaque particles in a water body environment. In particular, a focus parameter model is employed to modify the original focus parameters in order to reliably identify particles. The modified focus parameters integrate the optical conditions, particle shape and degree of overlap, and depth of field effect as a function of particle size. Thus, the present invention provides an unbiased volume concentration estimation for an adaptive sampling volume that varies with particle size. Furthermore, for high concentration measurements, the poisson distribution of particles is used to correct for particle overlap effects.
The technical scheme adopted by the invention is as follows:
the backlight imaging system capable of simultaneously measuring the particle size and the volume concentration of particles comprises a support system, an illumination system, an imaging system and a calibration system; the support system provides support for connection and fixation of the imaging system and the illumination system; the illumination system provides a light source and transmits light uniformly to the imaging system; the imaging system is a core part of the whole system and is used for acquiring the data of the particle size and the volume concentration of the opaque particles in the water environment; the calibration system ensures the accuracy of the imaging system in acquiring data.
The lighting system comprises a flash lamp, an optical conduit and a control power supply A; the flash lamp is controlled by a control power supply A, the optical conduit transmits flash light to the imaging system in an air medium to realize relatively uniform white background light distribution, and the standard deviation of the space light value is used as a judgment standard;
the imaging system comprises a diffuser, an experimental water tank, a charge coupled camera, a control power supply B, an optical lens, a main control computer, a data acquisition board, an image acquisition computer and a frame acquisition board; the diffuser is connected with the optical conduit and receives the light emitted by the flash lamp; the experimental water tank is filled with impurity-free distilled water to provide an experimental liquid phase environment; the charge coupled camera has a digital progressive scanning function, and simultaneously selects pixels and frequency parameters of the charge coupled camera according to specific image acquisition requirements; the charge coupled camera is controlled by a control power supply B; the optical lens is arranged on the charge coupled camera; the main control computer is used for synchronizing the charge coupled camera and the flash lamp signal; the data acquisition board is used for providing a logic gate circuit level signal; the data acquisition board is connected with a main control computer; after receiving the trigger signal, the frame acquisition board acquires an image through a real-time digital recording system in the image acquisition computer, and transmits the acquired image to the hard disk for analysis;
the calibration system comprises a target A and a target B; the size of the target board A and the target board B meets the condition that the length and the width are equal, and the thickness value is less than one tenth of the length or the width value; the single surfaces of the target plate A and the target plate B are coated with chromium, the photoetching shapes are circular, triangular, square and oval, the length grades of the photoetching shapes are different and are different from micrometer to millimeter, and the precision of any photoetching shape is in a nanometer range;
the supporting system comprises a stainless steel frame, an optical guide rail, a precise translation stage A, a precise translation stage B, an operating handle A and an operating handle B; a stainless steel frame provides support for the imaging system and the illumination system; placing a flash, a diffuser, a charge coupled camera on the optical track, the charge coupled camera being capable ofzThe direction moves horizontally; the precise translation stage A is connected with the target board A and can be arranged onx - zMoving on a plane, wherein the moving range is in a micron order; the precise translation stage B is connected with the target board B and can be arranged onx - yThe operation handle A is fixed at the left end of the precision translation stage B and controls the edge of the precision translation stage ByMovement of the shaft; the operating handle B is fixed at the lower end of the precision translation stage B and controls the edge of the precision translation stage BxMovement of the shaft; specifying the direction of the light source emitted by the flash lamp asxPositive axis, then x-axis andythe axes are determined by the right hand rule.
Further, the standard deviation of the space brightness value should satisfy the range of [ -5%, 5% ].
Further, the flash lamp has a light source broadband that meets measurement requirements, and can provide high pulse energy and frequency through an internal/external trigger; the reticle A and reticle B are lithographically identical in shape, but are interchanged between rows and columns to check for particle overlap effects; the wavelength of the flash lamp is less than one twentieth of the minimum length of the shapes on the target plate A and the target plate B, and the wavelength of the flash lamp belongs to the micron level; the focal length of the charge coupled camera is more than ten times of the maximum length of the shapes on the target board A and the target board B, and the focal length of the charge coupled camera belongs to millimeter level; the bandwidth of the light emitted by the flash lamp is more than ten times of the maximum length of the shapes on the target plate A and the target plate B, and different photoetching shapes on the target plate A and the target plate B are used for simulating sticky particles and non-sticky particles; the different lithographic shapes on the reticle A and the reticle B are opaque.
The method for utilizing the backlight imaging system capable of simultaneously measuring the particle size and the volume concentration of the particles comprises the following steps:
s1, checking and adjusting the support system: keeping the stainless steel frame and the optical guide rail horizontal; according to the measurement requirement, the precision translation table A and the precision translation table B are placed at corresponding positions by utilizing the control handle A and the control handle B;
s2, turning on the lighting system: turning on a flash lamp by controlling a power supply A, conveying the flash light in an air medium to a diffuser in the imaging system through an optical conduit, and checking the relative uniformity of the light distribution of the white background by taking the standard deviation of the space light value as a judgment standard;
s3, preparing imaging conditions: filling an experiment water tank with impurity-free distilled water to provide a liquid phase environment for subsequent experiments; installing an optical lens on the charge coupled camera and starting the optical lens by controlling a power supply B; checking that the aperture diameter, the focal length and the magnification parameter of the optical lens meet the requirement of measurement precision; synchronizing signals of a charge coupled camera and a flash lamp by a main control computer; preliminarily feeding back a logic gate circuit level signal acquired by a data acquisition board to a main control computer; after receiving the trigger signal, the frame acquisition board acquires images through a real-time digital recording system in the image acquisition computer and transmits the acquired images to the hard disk; performing preliminary analysis on the acquired basic data to ensure the normal operation of the imaging system;
s4, calibrating the system: checking and determining that the wavelength of the flash lamp is less than one twentieth of the minimum length of the shapes on the target A and the target B, wherein the wavelength of the flash lamp belongs to the micron level; the focal length of the charge coupled camera is more than ten times of the maximum length of the shapes on the target board A and the target board B, and the focal length of the charge coupled camera belongs to millimeter level; the bandwidth of the emitted light of the flash lamp is more than ten times of the maximum length of the shapes on the target A and the target B; interchanging the lines and the rows of the photoetching patterns in the standard plate A and the standard plate B, checking the overlapping effect of particles, and finally obtaining an actual length scale under the experimental condition;
and S5, particle identification data processing: the identification process comprises edge detection, image segmentation and feature extraction; the particle edges are determined by the local maximum gray gradient; assigning the detected edge and interior pixels to particles and remaining pixels to the fluid, enabling segmentation of each image into particles and background regions;by making the particle region
Fitting the particles into a circle, marking the identified particles, extracting the image diameter of the identified particles, and further calculating the measured diameter;
s6, data processing for selecting focused particles: defining focus parameters
(ii) a If it is used
If a predetermined threshold of particles in the size range is exceeded, counting the particles in the sample volume and determining the particle size; calculating the measured particle volume concentration
；
S7, establishing a focusing parameter model and verifying: in order to evaluate the influence of particle size, refractive index, overlapping degree, magnification, light intensity and camera vision on focusing parameters, a focusing parameter model is established firstly; according to optical principles, for a single illuminated particle in an infinite fluid, the amount of light reaching the image plane from the particle is determined, assuming a thin lens is used
(ii) a After considering the gaussian intensity distribution of the shadow flux, the individual, spherical, opaque, back-facing light-emitting particles, considered as point sources, were evaluated for their image light intensity distribution
(ii) a The maximum shadow intensity is obtained by integrating the shadow intensity over the particle image and equating it to the energy loss due to blocking of the luminescent particlesI 0 (ii) a Searching the maximum value of the light intensity distribution gradient in the space; at a distance from the optical planezAt distance, the image diameter of the particle is estimated
(ii) a Comprehensively considering the influence of particle size, refractive index, overlapping degree, magnification, light intensity and camera vision, namely providing non-deviation volume concentration estimation aiming at the self-adaptive sampling volume changing along with the particle size and determining the focus parameter model
(ii) a Finally, focus parameter model verification is performed using the data processed in steps S5 and S6.
Further, in step S5, the image diameter is
Then measure the diameter of
Wherein
Is the magnification of the optical lens.
Further, in step S6, the focusing parameters
Is represented as follows:
 |
（1） |
in the formula (I), the compound is shown in the specification,
is a parameter that depends on optical and particle properties;
said calculating a measured particle volume concentration
Expressed as:
 |
（2） |
in the formula (I), the compound is shown in the specification,
in the particle size range
The number of (c);
Further, in step S7, the amount of light that the particles reach the image plane
Comprises the following steps:
 |
（3） |
in the formula (I), the compound is shown in the specification,
the average amount of light blocked for the particles;
the image light intensity distribution
Expressed as:
 |
（4） |
in the formula (I), the compound is shown in the specification,
the image light intensity of the background area;
the maximum shadow intensity
Expressed as:
 |
（5） |
the estimation particleDiameter of the image
Expressed as:
 |
（6） |
in the formula (I), the compound is shown in the specification,
is the wavelength of the light;
of said focus parameter model
Expressed as:
 |
（7） |
in the formula (I), the compound is shown in the specification,
is a model coefficient having a value equal to
，
Is the average diameter of all measured particles.
The invention has the beneficial effects that:
1. the backlight imaging system has the advantages of ingenious structure, simple assembly and good integrity.
2. The present invention employs a focus parameter model to modify the original focus parameters to reliably identify particles, and the modified focus parameters integrate the effects of optical conditions, particle shape and degree of overlap, and depth of field as a function of particle size.
3. The invention adopts the Poisson distribution of particles to correct the particle overlapping effect for high-concentration solid-liquid two-phase measurement.
4. The present invention provides an unbiased estimation of particle size and volume concentration for an adaptive sampling volume that varies with particle size.
Drawings
FIG. 1 is a schematic front view of the system of the present invention;
FIG. 2 is an enlarged partial view of the lithographic pattern on reticle A/B of the system of the present invention;
fig. 3 is a flow chart of the method of the present invention.
In the figure: 1. the system comprises a flash lamp, 2 an optical guide pipe, 3 a control power supply A, 4 a diffuser, 5 an experimental water tank, 6 a charge coupled camera, 7 a control power supply B, 8 an optical lens, 9 a main control computer, 10 a data acquisition board, 11 an image acquisition computer, 12 a frame acquisition board, 13 a target board A, 14 a target board B, 15 a stainless steel frame, 16 an optical guide rail, 17 a precision translation stage A, 18 a precision translation stage B, 19 a control handle A, 20 a control handle B, 21 a photoetching pattern.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the backlight imaging system of the device of the present invention is divided into four subsystems: a support system, an illumination system, an imaging system, and a calibration system. The support system provides a physical basis for the connection and fixation of the imaging system and the illumination system; an illumination system provides a high quality light source and delivers light uniformly to the imaging system; the imaging system is a core part of the whole system and mainly acquires basic effective data such as the particle size, the volume concentration and the like of the opaque particles in the water environment; the calibration system ensures the accuracy of the data acquired by the imaging system.
The lighting system comprises a flash 1, an optical conduit 2 and a control power supply a 3. The flashlight 1 is controlled by a control power supply A3; the flash lamp 1 needs to have a light source bandwidth of 100 to 1100 nm, and can provide 125 joules of energy through an internal/external trigger, with a specified frequency of no less than 160 Hz; the optical conduit 2 delivers the flash of light to the imaging system in an air medium, achieving a relatively uniform (spatial rate of change < ± 5%, i.e. standard deviation of the spatial light values) white background light distribution.
The imaging system comprises a diffuser 4, an experimental water tank 5, a charge coupled camera 6, a control power supply B7, an optical lens 8, a main control computer 9, a data acquisition board 10, an image acquisition computer 11 and a frame acquisition board 12. The diffuser 4 is connected with the optical conduit 2 and receives the light emitted by the flash lamp 1; the experiment water tank 5 is filled with impurity-free distilled water to provide an experiment liquid phase environment; the ccd camera 6 has a progressive scan function of 1024 × 1024 pixels (12 μm × 12 μm per pixel) and 12-bit digitization (4096 gray levels), which can capture 30 frames per second (fps) images; the charge coupled camera 6 has excellent resolution and gray scale characteristics and has high fill-in performance to ensure good quantifiable image quality; the charge coupled camera 6 is controlled by a control power supply B7; the optical lens 8 is arranged on the charge coupled camera 6; the diameter of the optical lens 8 is 3.75 cm, the focal length is 355 mm, and the magnification is 0.62; the main control computer 9 is used for synchronizing the charge coupled camera 6 and the flash lamp 1; the data acquisition board 10 is used to provide TTL (logic gate circuit) level signals; the data acquisition board 10 is connected with the main control computer 9; upon receiving the trigger signal, the frame acquisition board 12 acquires an image through a real-time digital recording system in the image acquisition computer 11, and transmits the acquired image to a hard disk for analysis.
The calibration system includes target A13 and target B14. Flash lamp 1 wavelength is much smaller than the smallest particle size (i.e., micron size) of the shapes on target a13 and target B14; the focal length of the charge coupled camera 6 is much larger than the maximum particle size (i.e. millimeter level) of the shapes on the target a13 and target B14; the bandwidth of the light of the flash lamp 1 is far larger than the maximum particle size (millimeter level) of the shapes on the target A13 and the target B14, and different photoetching shapes on the target A13 and the target B14 can be used for simulating various types of particles; the different lithographic shapes on target a13 and target B14 are opaque and the flash is transferred from air through the glass to water and from water through the glass to air, so the refraction effect is negligible; the flash lamp 1 is broadband and diffraction of light can be disregarded.
The support system comprises a stainless steel frame 15, an optical guide rail 16, a precision translation stage A17, a precision translation stage B18, a control handle A19 and a control handle B20. The stainless steel frame 15 provides a support foundation for the system; the flash lamp 1, the diffuser 4 and the charge coupled camera 6 are arranged on the optical guide rail 16, and the charge coupled camera 6 can be arranged on the optical guide rail 16zThe direction moves horizontally; the precision translation stage A17 is connected to a target A13, and the precision translation stage A17 is arranged on the targetx - zMoving on a plane with the moving range of 25 micrometers; the precise translation stage B18 is connected with a target B14 and is a precise translation stageB18 can be inx - yThe plane movement is controlled by a control handle A19 and a control handle B20, the control handle A19 is fixed at the left end of the precision translation stage B18, and the control of the precision translation stage B18 along the planeyMovement of the shaft; an operating handle B20 is fixed at the lower end of the precision translation stage B18 and controls the precision translation stage B18 to move alongxThe movement of the shaft. It should be noted that the direction of the light source emitted from the strobe light 1 is defined asxPositive axis, then x axis andythe axes are determined by the right hand rule.
As shown in fig. 2, the dimensions of the target a13 and the target B14 are 10 cm × 3 mm, the single surface is coated with chromium, the mask is photoetched to be round, triangular, square and elliptical, there are 52 different size grades, which are from 5 to 1000 micrometers, and the precision of any shape is within the range of ± 100 nanometers; reticle A13 and reticle B14 lithographically depict the same lithographic pattern 21, but are interchanged between rows and columns to check for particle overlay effects.
As shown in fig. 3, the backlight imaging method for simultaneously measuring particle size and volume concentration of particles of the present invention comprises the following steps:
s1, the checking and adjusting support system: keeping the stainless steel frame 15 and the optical guide rail 16 horizontal; according to the measurement requirements, the precision translation stage A17 and the precision translation stage B18 are placed at corresponding positions by using the control handle A19 and the control handle B20.
S2, turning on the lighting system: the flash 1 was turned on by controlling the power supply a3, and the flash was delivered in an air medium through the optical conduit 2 to the diffuser 4 in the imaging system, and the relative uniformity of the white background light distribution was checked against the standard deviation of the spatial light value as a criterion.
S3, preparing imaging conditions: filling the experiment water tank 5 with impurity-free distilled water to provide a liquid phase environment for subsequent experiments; the optical lens 8 is arranged on the charge coupled camera 6 and is turned on by controlling the power supply B7; the diameter of the inspection optical lens 8 is 3.75 cm, the focal length is 355 mm, and the magnification is 0.62; synchronizing signals of the charge coupled camera 6 and the flash lamp 1 by a main control computer 9; initially feeding back a TTL (logic gate circuit) level signal acquired by the data acquisition board 10 to the main control computer 9; after receiving the trigger signal, the frame acquisition board 12 acquires an image through a real-time digital recording system in the image acquisition computer 11, and transmits the acquired image to the hard disk; and carrying out preliminary analysis on the acquired basic data to ensure the normal operation of the imaging system.
S4, calibrating the system: the wavelength of the flash lamp 1 is determined to be far smaller than the minimum particle size (micron level) of the shapes on the target A13 and the target B14, the focal length of the charge coupled camera 6 is far larger than the maximum particle size (millimeter level) of the shapes on the target A13 and the target B14, and the bandwidth of the light of the flash lamp 1 is far larger than the maximum particle size (millimeter level) of the shapes on the target A13 and the target B14; and interchanging the rows and the columns of the photoetching patterns 21 in the target A13 and the target B14, and checking the overlapping effect of the particles to finally obtain the actual length scale under the experimental condition.
And S5, particle recognition data processing: the identification process comprises edge detection, image segmentation and feature extraction. The particle edges are determined by the local maximum gray gradient; assigning the detected edge and interior pixels to particles and the remaining pixels to fluid, enabling segmentation of each image into particle and background regions; by making the particle region
Fitting to a circle, labeling the identified particles, and extracting the diameter of the image as
Then measure the diameter of
Wherein
Is the magnification of the optical lens 8.
S6, data processing for selecting focused particles: defining focus parameters
Is represented as follows:
 |
（1） |
in the formula (I), the compound is shown in the specification,
is a parameter that depends on optical and particle properties;
If it is not
If a predetermined threshold for particles in the size range is exceeded, the particles are counted in the sample volume and their size is determined. The measured particle volume concentration may be calculated as:
 |
（2） |
in the formula (I), the compound is shown in the specification,
in the particle size range
The number of (2);
S7, establishing a focusing parameter model and verifying: to evaluate the effect of particle size, refractive index, degree of overlap and other optical conditions (magnification, light intensity, camera field of view) on the focus parameters, a focus parameter model was first established. According to optical principles, for a single illuminated particle in an infinite fluid, the amount of light reaching the image plane from the particle is assumed to be using a thin lens
Comprises the following steps:
 |
（3） |
in the formula (I), the compound is shown in the specification,
the average amount of light blocked for the particles;
Gaussian intensity distribution taking into account shadow flux
Rear, single, spherical, opaque, back-to-back lightingImage light intensity distribution of particles (as point light sources)
Comprises the following steps:
 |
（4） |
in the formula (I), the compound is shown in the specification,
the image light intensity of the background area;
By integrating the intensity of the shadow on the particle image and equating it to the energy loss due to blocking of the luminescent particle
The maximum shadow intensity is:
 |
（5） |
by setting up
To look for
Wherein the image diameter of the particles
Can be expressed as
. Thus, at a distance from the optical planezAt a distance from, canThe image diameter of the particles was estimated as:
 |
（6） |
in the formula (I), the compound is shown in the specification,
is the wavelength of the light;
simultaneous formulas (1) to (6) give:
 |
（7） |
in the formula (I), the compound is shown in the specification,
is a model coefficient whose value is equal to
，
Is the average diameter of all measured particles.
Equation (7) gives a focus parameter model
The influence of particle size, refractive index, degree of overlap and other optical conditions (magnification, light intensity, camera view) are comprehensively considered, i.e. a non-biased volume concentration estimation is provided for an adaptive sampling volume which varies with the particle size.
Finally, focus parameter model verification is performed using the data processed at S5 and S6.
In the description of the present invention, it is to be understood that the terms "inner", "side", "upper", "lower", "thickness", "width", "front", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.
In the present invention, unless otherwise expressly stated or limited, the terms "disposed" and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The invention is described above as a preferred embodiment, not limited to the scope of the invention, and all equivalent modifications made by the content of the present specification, or any other technical fields directly or indirectly using the attached related products, are included in the scope of the present invention.
Claims (8)
1. But backlight imaging system of simultaneous measurement particle diameter and volume concentration, its characterized in that: the system comprises a support system, an illumination system, an imaging system and a calibration system; the support system provides support for the connection and fixation of the imaging system and the illumination system; the illumination system provides a light source and transmits light uniformly to the imaging system; the imaging system is a core part of the whole system and is used for acquiring the data of the particle size and the volume concentration of the opaque particles in the water environment; the calibration system ensures the accuracy of the imaging system in acquiring data.
2. The backlight imaging system of claim 1, wherein the backlight imaging system is capable of simultaneously measuring particle size and volume concentration, and comprises: the lighting system comprises a flash lamp, an optical conduit and a control power supply A; the flash lamp is controlled by a control power supply A, the optical conduit transmits flash light to the imaging system in an air medium to realize relatively uniform white background light distribution, and the standard deviation of the space light value is relatively uniform and taken as a judgment standard;
the imaging system comprises a diffuser, an experimental water tank, a charge coupled camera, a control power supply B, an optical lens, a main control computer, a data acquisition board, an image acquisition computer and a frame acquisition board; the diffuser is connected with the optical conduit and receives the light emitted by the flash lamp; the experimental water tank is filled with impurity-free distilled water to provide an experimental liquid phase environment; the charge coupled camera has a digital progressive scanning function, and simultaneously selects pixels and frequency parameters of the charge coupled camera according to specific requirements of image acquisition; the charge coupled camera is controlled by a control power supply B; the optical lens is arranged on the charge coupled camera; the main control computer is used for synchronizing the charge coupled camera and the flash lamp signal; the data acquisition board is used for providing a logic gate circuit level signal; the data acquisition board is connected with a main control computer; after receiving the trigger signal, the frame acquisition board acquires an image through a real-time digital recording system in the image acquisition computer, and transmits the acquired image to the hard disk for analysis;
the calibration system comprises a target A and a target B; the size of the target board A and the target board B meets the condition that the length and the width are equal, and the thickness value is less than one tenth of the length or the width value of the target board A; the single surfaces of the target plate A and the target plate B are coated with chromium, the photoetching shapes are circular, triangular, square and oval, the length grades of the photoetching shapes are different and are different from micrometer to millimeter, and the precision of any photoetching shape is in a nanometer range;
the supporting system comprises a stainless steel frame, an optical guide rail, a precise translation stage A, a precise translation stage B, an operating handle A and an operating handle B; a stainless steel frame provides support for the imaging system and the illumination system; placing a flash, a diffuser, a charge coupled camera on the optical track, the charge coupled camera being capable of being onzThe direction moves horizontally; the precise translation stage A is connected with the target board A and can be arranged onx - zMoving on a plane, wherein the moving range is in a micron order; the precise translation stage B is connected with the target board B and can be arranged onx - yThe plane moves and is controlled by an operating handle A and an operating handle B, the operating handle A is fixed at the left end of the precision translation stage B, and the edge of the precision translation stage B is controlledyMovement of the shaft; the operating handle B is fixed at the lower end of the precise translation stage B and controls the edge of the precise translation stage BxMovement of the shaft; specifying the direction of the light source emitted by the flash lamp asxPositive axis, then x axis andythe axes are determined by the right hand rule.
3. The backlight imaging system of claim 2, wherein the backlight imaging system is capable of simultaneously measuring particle size and volume concentration, and comprises: the standard deviation of the space brightness value needs to satisfy the range of [ -5%, 5% ].
4. The backlight imaging system of claim 2, wherein the backlight imaging system is capable of simultaneously measuring particle size and volume concentration, and comprises: the flash lamp has a light source broadband meeting the measurement requirements, and can provide high pulse energy and frequency through an internal/external trigger; the reticle A and reticle B are lithographically identical in shape, but are interchanged between rows and columns to check for particle overlap effects; the wavelength of the flash lamp is less than one twentieth of the minimum length of the shapes on the target A and the target B, and the wavelength of the flash lamp belongs to the micron level; the focal length of the charge coupled camera is more than ten times of the maximum length of the shapes on the target board A and the target board B, and the focal length of the charge coupled camera belongs to millimeter level; the bandwidth of the light emitted by the flash lamp is more than ten times of the maximum length of the shapes on the target plate A and the target plate B, and different photoetching shapes on the target plate A and the target plate B are used for simulating sticky particles and non-sticky particles; the different lithographic shapes on the target A and the target B are opaque.
5. The method of using the back-light imaging system capable of simultaneously measuring particle size and volume concentration as claimed in any 1 of claims 1 to 4, wherein: it comprises the following steps:
s1, checking and adjusting the support system: keeping the stainless steel frame and the optical guide rail horizontal; according to the measurement requirement, the precision translation table A and the precision translation table B are placed at corresponding positions by utilizing the control handle A and the control handle B;
s2, turning on the lighting system: turning on a flash lamp by controlling a power supply A, conveying the flash light in an air medium to a diffuser in the imaging system through an optical conduit, and checking the relative uniformity of the light distribution of the white background by taking the standard deviation of the space light value as a judgment standard;
s3, preparing imaging conditions: filling an experiment water tank with impurity-free distilled water to provide a liquid phase environment for subsequent experiments; the optical lens is arranged on the charge coupled camera and is started by controlling a power supply B; checking that the aperture diameter, the focal length and the magnification parameter of the optical lens meet the requirement of measurement precision; synchronizing signals of a charge coupled camera and a flash lamp by a main control computer; preliminarily feeding back a logic gate circuit level signal acquired by a data acquisition board to a main control computer; after receiving the trigger signal, the frame acquisition board acquires an image through a real-time digital recording system in the image acquisition computer and transmits the acquired image to the hard disk; performing preliminary analysis on the acquired basic data to ensure the normal operation of the imaging system;
s4, calibrating the system: checking and determining that the wavelength of the flash lamp is less than one twentieth of the minimum length of the shapes on the target A and the target B, wherein the wavelength of the flash lamp belongs to the micron level; the focal length of the charge coupled camera is more than ten times of the maximum length of the shapes on the target board A and the target board B, and the focal length of the charge coupled camera belongs to millimeter level; the bandwidth of the emitted light of the flash lamp is more than ten times of the maximum length of the shapes on the target A and the target B; interchanging the lines and columns of the photoetching patterns in the target plate A and the target plate B, checking the overlapping effect of particles, and finally obtaining an actual length scale under the experimental condition;
and S5, particle identification data processing: the identification process comprises edge detection, image segmentation and feature extraction; the particle edges are determined by the local maximum gray gradient; assigning the detected edge and interior pixels to particles and the remaining pixels to fluid, enabling segmentation of each image into particle and background regions; by making the particle region
Fitting the particles into a circle, marking the identified particles, extracting the image diameter of the identified particles, and further calculating the measured diameter;
s6, data processing for selecting focused particles: defining focus parameters
(ii) a If it is not
If a predetermined threshold of particles in the size range is exceeded, counting the particles in the sample volume and determining the particle size; calculating the measured particle volume concentration
；
S7, establishing a focusing parameter model and verifying: in order to evaluate the influence of particle size, refractive index, overlapping degree, magnification, light intensity and camera vision on focusing parameters, a focusing parameter model is established firstly; according to optical principles, for a single illuminated particle in an infinite fluid, the amount of light reaching the image plane from the particle is determined, assuming a thin lens is used
(ii) a After considering the gaussian intensity distribution of the shadow flux, the individual, spherical, opaque, back-facing light-emitting particles, considered as point sources, were evaluated for their image light intensity distribution
(ii) a The maximum shadow intensity is obtained by integrating the shadow intensity over the particle image and equating it to the energy loss due to the blocking of the luminescent particleI 0 (ii) a Searching the maximum value of the light intensity distribution gradient in the space; at a distance from the optical planezAt distance, the image diameter of the particle is estimated
(ii) a Comprehensively considering the influence of particle size, refractive index, overlapping degree, magnification, light intensity and camera vision, namely providing non-deviation volume concentration estimation aiming at the self-adaptive sampling volume changing along with the particle size and determining the focus parameter model
(ii) a Finally, focus parameter model verification is performed using the data processed in steps S5 and S6.
6. The backlight imaging method of claim 5, wherein the particle size and the volume concentration of the particles can be measured simultaneously, and the method comprises: in step S5, the image diameter is
Then measure the diameter of
In which
Is the magnification of the optical lens.
7. The backlight imaging method of claim 5, wherein the particle size and the volume concentration of the particles can be measured simultaneously, and the method comprises the following steps: in step S6, the focusing parameters
Is represented as follows:
in the formula (I), the compound is shown in the specification,
is a parameter that depends on optical and particle properties;
said calculating the measured particle volume concentration
Expressed as:
in the formula (I), the compound is shown in the specification,
in the particle size range
The number of (2);
8. The simultaneous measurable particle size and particle size of claim 5The backlight imaging method of volume concentration is characterized in that: in step S7, the amount of light that the particles reach the image plane
Comprises the following steps:
in the formula (I), the compound is shown in the specification,
the average amount of light blocked for the particles;
the image light intensity distribution
Expressed as:
in the formula (I), the compound is shown in the specification,
the image light intensity of the background area;
the maximum shadow intensity
Expressed as:
estimating an image diameter of a particle
Expressed as:
in the formula (I), the compound is shown in the specification,
is the wavelength of the light;
of said focus parameter model
Expressed as:
in the formula (I), the compound is shown in the specification,
is a model coefficient having a value equal to
，
Is the average diameter of all measured particles.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116330516A (en) * | 2023-05-29 | 2023-06-27 | 乳山市东方硅胶有限公司 | Particle size control system of silica gel particle production equipment |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2778243A1 (en) * | 1998-04-29 | 1999-11-05 | Cilas | Determining the granulometric composition of a mixture of particles, applicable to particles ranging from tenth of mm to centimeter and even to crushed rocks |
| CN101952709A (en) * | 2007-11-15 | 2011-01-19 | 爱克斯崔里斯科技有限公司 | Particle detection |
| CN103076265A (en) * | 2013-01-11 | 2013-05-01 | 战仁军 | Measuring device for particle distribution and particle diameter |
| CN103424406A (en) * | 2013-09-03 | 2013-12-04 | 上海理工大学 | Image method measuring device and method for gas-liquid two-phase flow in pipelines |
| CN105765364A (en) * | 2013-11-20 | 2016-07-13 | 马尔文器械有限公司 | Improvements in or relating to calibration of instruments |
| CN105928847A (en) * | 2016-04-19 | 2016-09-07 | 中国科学院过程工程研究所 | On-line measuring method for concentration and particle size of particles in a multiphase system |
| CN106323825A (en) * | 2016-10-26 | 2017-01-11 | 浙江大学 | Pipeline powdered coal particle size measuring device and measuring method |
| CN107144503A (en) * | 2017-05-19 | 2017-09-08 | 上海理工大学 | Liquid fuel spray burning drop and flame synchronous measuring apparatus and method |
| CN109945776A (en) * | 2019-02-01 | 2019-06-28 | 天津大学 | A kind of displacement/strain measurement method in electrochemistry based on fluorescent particle markers and active optics measurement |
| CN110146422A (en) * | 2019-05-27 | 2019-08-20 | 中国计量大学 | A kind of dust concentration detection device based on multi-angle acquisition image |
| CN110672476A (en) * | 2019-09-27 | 2020-01-10 | 上海理工大学 | Online measurement method for concentration and granularity of catering oil fume particles |
| CN113218844A (en) * | 2021-05-28 | 2021-08-06 | 上海睿钰生物科技有限公司 | Method for analyzing particles in sample to be detected |
-
2022
- 2022-08-24 CN CN202211016706.8A patent/CN115096768A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2778243A1 (en) * | 1998-04-29 | 1999-11-05 | Cilas | Determining the granulometric composition of a mixture of particles, applicable to particles ranging from tenth of mm to centimeter and even to crushed rocks |
| CN101952709A (en) * | 2007-11-15 | 2011-01-19 | 爱克斯崔里斯科技有限公司 | Particle detection |
| CN103076265A (en) * | 2013-01-11 | 2013-05-01 | 战仁军 | Measuring device for particle distribution and particle diameter |
| CN103424406A (en) * | 2013-09-03 | 2013-12-04 | 上海理工大学 | Image method measuring device and method for gas-liquid two-phase flow in pipelines |
| CN105765364A (en) * | 2013-11-20 | 2016-07-13 | 马尔文器械有限公司 | Improvements in or relating to calibration of instruments |
| CN105928847A (en) * | 2016-04-19 | 2016-09-07 | 中国科学院过程工程研究所 | On-line measuring method for concentration and particle size of particles in a multiphase system |
| CN106323825A (en) * | 2016-10-26 | 2017-01-11 | 浙江大学 | Pipeline powdered coal particle size measuring device and measuring method |
| CN107144503A (en) * | 2017-05-19 | 2017-09-08 | 上海理工大学 | Liquid fuel spray burning drop and flame synchronous measuring apparatus and method |
| CN109945776A (en) * | 2019-02-01 | 2019-06-28 | 天津大学 | A kind of displacement/strain measurement method in electrochemistry based on fluorescent particle markers and active optics measurement |
| CN110146422A (en) * | 2019-05-27 | 2019-08-20 | 中国计量大学 | A kind of dust concentration detection device based on multi-angle acquisition image |
| CN110672476A (en) * | 2019-09-27 | 2020-01-10 | 上海理工大学 | Online measurement method for concentration and granularity of catering oil fume particles |
| CN113218844A (en) * | 2021-05-28 | 2021-08-06 | 上海睿钰生物科技有限公司 | Method for analyzing particles in sample to be detected |
Non-Patent Citations (1)
| Title |
|---|
| CHEEGWAN LEE ET.AL: "Simultaneous particle size and concentration measurements using a back-lighted particle imaging system", 《FLOW MEASUREMENT AND INSTRUMENTATION》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116330516A (en) * | 2023-05-29 | 2023-06-27 | 乳山市东方硅胶有限公司 | Particle size control system of silica gel particle production equipment |
| CN116330516B (en) * | 2023-05-29 | 2023-08-29 | 乳山市东方硅胶有限公司 | Particle size control system of silica gel particle production equipment |
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