JP7307497B2 - Particle swarm measuring device - Google Patents

Description

The present invention relates to a particle swarm measuring device.

It is known that fine particles contained in automobile exhaust gas and aerosols such as yellow sand flying from the continent contain many submicron particles with a particle size of less than 1 μm. In addition, with the recent development of liquid atomization technology, it has become possible to generate fine spray with an arithmetic mean particle size on the order of several μm, and it is estimated that the lower limit of the particle size distribution is already in the region of 1 μm or less. be. In order to understand the behavior of such submicron particles, it is essential to establish a particle size measurement method.

Prior art documents close to the technical field of the present invention are shown in Patent Document 1 and Non-Patent Document 1.
Patent Document 1 discloses a particle size measuring device and a particle size measuring method, which are the basic technology of the present invention by the inventor of the present application.
Non-Patent Document 1 describes a particle size measurement method targeting a particle size range including a submicron region of the order of 1 nm to 10 μm, and describes the characteristics of the measurement method according to each particle size range. be. Particle size measurement methods are broadly classified into non-contact methods and collection methods.

Non-contact particle size measurement methods mainly use laser beams, such as the laser diffraction method using the scattering pattern, the light scattering method using the scattered light intensity, and the frequency variation of the scattered light due to particle motion. A dynamic light scattering method and the like are known. Since these methods use a laser beam as a probe, non-contact measurement is possible, and depending on the method, two-dimensional measurement is possible.

The laser diffraction method and the light scattering method have a particle size measurement range of the order of 100 nm to 100 μm, and are widely used for particle size measurement of fuel spray, powder, and the like. However, at present, there are many difficulties in directly applying the method to particles having an average particle size of 1 μm or less.

The dynamic light scattering method is capable of measuring extremely minute particle diameters of the order of 1 nm to 1 μm, and has been applied to observation of the generation process of fine particles in flames with great results. However, since it requires a powerful laser light source and complicated signal processing, and since it is based on point measurement, many experiments are required to acquire two-dimensional data. I had difficulties.

There are many collection-type particle size measurement methods that collect and analyze particles, such as measurement methods using optical and electron microscopes, inertial collision methods, gravity sedimentation/centrifugal sedimentation methods, electrical detection zone methods, and electrostatic classification methods. method is known. In such a sampling-type particle size measurement method, depending on the technique, it is possible to measure extremely small particle sizes on the order of 1 nm. However, since it is necessary to collect and analyze the particles, there is a problem that valuable information such as the spatial distribution and temporal change of the particle size is lost.

On the other hand, a polarization ratio method is known as a submicron particle size measurement method using a laser beam. The polarization ratio method has been developed as a particle size measurement method for aerosols. The polarization ratio method utilizes the property that the intensity ratio of two polarized light components contained in scattered light from particles depends on the particle size.

The particle size measurement method using the polarization ratio method has the great advantage that even particles smaller than the laser wavelength can be measured and non-contact particle size measurement is possible. However, the measurable particle size range is narrow and currently limited to 1 nm to 100 nm.

Therefore, the particle size measurement range of the polarization ratio method does not overlap with that of the laser diffraction method and the scattered light method, and there is a demand for the development of a particle size measurement method that fills the gap between the two.

Japanese Patent No. 5517000

Hiroshi Sakurai, Measurement techniques and standards for airborne particle number concentration and particle size distribution, AIST Measurement Standard Report, National Institute of Advanced Industrial Science and Technology, Vol.4, No.1, 53-63.

In the patent shown in Patent Document 1, the inventor realizes a particle size measuring device and a particle size measuring method that can measure the particle size without contacting the particles to be measured and can expand the measurable particle size range. bottom. However, the measurable particle size range in Patent Document 1 is about several hundred nm to 10 μm. has also not been applied.

When fuel is burned in a cylinder of an engine such as a passenger car, soot is instantaneously generated inside the piston, and the soot grows within a very short period of time. These soot particles have extremely small particle sizes of several nanometers to several tens of nanometers. Naturally, it is impossible to measure the particle size of such extremely small particles that are generated and grow in an extremely short period of time without contact, and there has been no method that can be realized so far.

Also, the soot generated inside the flame is not composed of a single particle size. It roughly follows a lognormal distribution, with a mean and a variance. In addition, it exhibits a refractive index, which is a unique optical constant determined by the constituent elements of the particles and their bonding structures. In order to measure soot particles, it is necessary to obtain not only the particle diameter but also the average particle diameter, the dispersion of the particle diameter, the number of particles, the refractive index, and the like.

The present invention has been made in view of such a situation, and estimates the particle size of particles to be measured, the average value of particle sizes, the dispersion of particle sizes, the number of particles, and the refractive index in a non-contact and extremely short time. An object of the present invention is to provide a particle swarm measuring device capable of

In order to solve the above problems, the particle swarm measuring apparatus of the present invention includes a first light source that irradiates a first light having a first wavelength on an optical path passing through a measurement target, and a first wavelength and a first light on the optical path. A second light source that irradiates a second light having a different second wavelength, and a predetermined scattering angle + θ in a direction parallel to an observation plane including the optical path with the measurement target as the center from the optical path. a first polarization camera that receives light from a first light source and outputs first scattered light intensity data; a second polarizing camera positioned at an angle -θ for receiving light from the second light source and outputting second scattered light intensity data;

Further, a light intensity field storing a theoretical value of scattered light intensity, a refractive index field storing a refractive index, a standard deviation field storing a standard deviation, and an average particle diameter in an assumed particle group are stored. The scattered light intensity data and the theoretical scattered light intensity value are compared with the scattered light intensity theoretical value table having the average particle size field stored in the table and the particle number field in which the number of particles is stored, and the record with the highest degree of similarity and a distance minimum value calculator that outputs the refractive index, the standard deviation, the average particle size, and the number of particles.

According to the present invention, particle group measurement capable of estimating the particle diameter of the particles to be measured, the average particle diameter, the dispersion of the particle diameter, the number of particles, and the refractive index in a non-contact and extremely short time Equipment can be provided.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a schematic diagram showing the overall configuration of a particle swarm measuring device according to an embodiment of the present invention; FIG. It is a schematic diagram showing the internal configuration of a polarization camera used in the particle swarm measuring device and the measurement values to be used. It is a block diagram which shows the hardware constitutions of a particle swarm measuring device. It is a block diagram which shows the software function of a particle swarm measuring device. FIG. 10 is a table showing the field configuration of a scattering value intensity theoretical value table; FIG. 4 is a graph showing a particle group model represented by records recorded in a scattering value intensity theoretical value table; 4 is a graph showing the relationship between the particle size of a particle group and the polarization ratio for light of a certain wavelength. 4 is a graph showing the relationship between the particle size of a particle group and the polarization ratio for light of two wavelengths. It is a graph of the experimental result of having conducted the experiment which measured the soot of a flame with the PAMS method which is a prior art, and the particle group measuring device which concerns on embodiment of this invention.

[Particle swarm measuring device: overall configuration]
FIG. 1 is a schematic diagram showing the overall configuration of a particle swarm measuring device 101 according to an embodiment of the present invention.
In FIG. 1, the flame 102 is the measurement target of the particle group measuring device 101 .
An observation plane D103 is a generally horizontal plane that passes through the flame 102, which is the object of measurement.
Linearly polarized light traveling straight along an optical path D116 formed on the observation plane D103 in a direction parallel to the observation plane D103 by the first light source 104, the second light source 105, the light combiner 106 such as a prism, the polarizing filter 107 and the convex lens 108. B109 is formed.

The first light source 104 is a laser light source that outputs light of a first wavelength (first light). The wavelength of the laser is, for example, 405 nm, a violet laser.
The second light source 105 is a laser light source that outputs light of a second wavelength (second light). The wavelength of the laser is, for example, 488 nm, and is a blue laser.
These purple and blue colors are selected to remove as much noise as possible from the orange light emitted by the flame 102 to be measured.

The optical combiner 106 aligns the optical axes of two laser beams, a violet laser beam emitted by the first light source 104 and a blue laser beam emitted by the second light source 105, and outputs the laser beams in one direction.
A polarizing filter 107 is provided to transmit polarized light having an oblique angle of 45°. This is in order to obtain uniform output polarization in the vertical and horizontal directions.
A convex lens 108 is provided to converge the light flux of the laser light.

Linearly polarized light B 109 passes through the flame 102 being measured and hits a beam stop 110, also called a beam trap or beam block. Beam stop 110 is provided for safety and any configuration that does not diffuse the laser light may be used.
When the linearly polarized light B109 passes through the flame 102 to be measured, the linearly polarized light B109 is diffused at a predetermined scattering angle ±θ in a direction parallel to the observation plane D103.

A first polarization camera 111 is installed on one side of the scattering angle ±θ +θ. The first polarization camera 111 detects the intensity of the light from the first light source 104 through a first color filter 112 that transmits only the wavelength of 405 nm of the light from the first light source 104 .
A second polarization camera 113 is installed on the other side −θ of the scattering angle ±θ. A second polarization camera 113 detects the intensity of the light from the second light source 105 through a second color filter 114 that transmits only the wavelength of 488 nm of the light from the second light source 105 .
The absolute value |θ| of the scattering angle ±θ can be set approximately between 30° and 80° and between 100° and 150°. Ideally, the ranges of 60°-80° and 100°-120° are preferred.
In the case of particles of about 10 nm, 90° is a singular point. At 90°, the intensity of the second scattered light becomes zero and cannot be measured. Therefore, positions that avoid 90° and are not too close to 0° and 180° are preferred.

[Polarization camera]
The configuration of the polarization camera 201 and the types of data used by the information processing device 115, which will be described later, will be described with reference to FIG.
FIG. 2 is a schematic diagram showing the internal configuration of the polarization camera 201 used in the particle swarm measuring apparatus 101 and the measured values used.
The polarization camera 201 has, for example, an imaging device with 648×488 pixels. In this imaging device, each imaging pixel is provided with a minute polarizing plate 202 .

Four kinds of polarizing filters for laterally polarizing, right obliquely polarizing, vertical polarizing, and left obliquely polarizing filters are arranged in alignment with each imaging pixel in the micro polarizing plate 202 . Then, the polarization camera 201 outputs image data corresponding to each polarization.
The particle swarm measuring apparatus 101 of the present invention uses vertically polarized image data D203 and horizontally polarized image data D204 (324 × 244 pixels), right obliquely polarized image data D205 and left obliquely polarized image data D205. polarization image data D206 is not used.

Returning to FIG. 1, the description of the particle group measuring device 101 is continued.
The first polarization camera 111 and the second polarization camera 113 are connected to an information processing device 115 such as a personal computer. The information processing device 115 estimates and calculates the refractive index, standard deviation, average particle diameter, and number of particles of the soot contained in the flame 102 at a predetermined moment, that is, the particle group, by performing arithmetic processing to be described later.

[Information processing device 115]
FIG. 3 is a block diagram showing the hardware configuration of the information processing device 115. As shown in FIG.
The information processing device 115 includes a CPU 302 , a ROM 303 , a RAM 304 , a display unit 305 , an operation unit 306 , a nonvolatile storage 307 , and a serial interface (hereinafter abbreviated as “serial I/F”) 308 such as USB, which are connected to the bus 301 . Prepare.
A first polarization camera 111 and a second polarization camera 113 are connected to the serial I/F 308 .

FIG. 4 is a block diagram showing software functions of the information processing device 115. As shown in FIG.
The first polarization camera 111 captures the measurement first wavelength first scattered light intensity data (I 1λ1 ), which is the vertical polarization intensity value derived from the violet laser output by the first light source 104, and the measurement first wavelength first scattered light intensity data (I _1λ1 ), which is the horizontal polarization intensity value. Output wavelength second scattered light intensity data (I _2λ1 ).
The second polarization camera 113 captures the measured second wavelength first scattered light intensity data (I _1λ2 ), which is the vertically polarized intensity value derived from the blue laser output by the second light source 105, and the measured second wavelength, which is the horizontally polarized intensity value. Output wavelength second scattered light intensity data (I _2λ2 ).

Measurement first wavelength first scattered light intensity data (I _1λ1 ), measurement first wavelength second scattered light intensity data (I _2λ1 ), measurement second wavelength first scattered light intensity data (I _1λ2 ), each of which is a scalar value and the measured second wavelength second scattered light intensity data (I _2λ2 ) are input to the distance minimum value calculator 401 .
The distance minimum value calculator 401 reads the scattered light intensity theoretical value table 402, and obtains the first scattered light intensity data for the first wavelength (I _1λ1 ), the second scattered light intensity data for the first wavelength (I 2λ1 ), the second scattered light intensity data for the first wavelength (I _2λ1 ), and the Find the record closest to the dual wavelength first scattered light intensity data (I _1λ2 ) and the measured second wavelength second scattered light intensity data (I _2λ2 ). Then, the distance minimum value calculator 401 outputs the refractive index, standard deviation, average particle size, and number of particles of the particle group, which are stored in the closest record.

The exposure control unit 403 simultaneously outputs shutter pulses to the first polarizing camera 111 and the second polarizing camera 113, and sets the exposure time necessary for photographing. Although omitted in FIG. 4 , the exposure control unit 403 receives a predetermined control signal obtained from the outside and outputs shutter pulses to the first polarization camera 111 and the second polarization camera 113 .
Here, the predetermined control signal obtained from the outside is, for example, a timing pulse obtained from an engine model (not shown) or the like. The exposure control unit 403 gives a predetermined time delay to the control signal and strictly controls the exposure time, thereby making it possible to measure the state of soot at a desired moment in the combustion cycle of the engine.

[Scattered light intensity theoretical value table 402]
FIG. 5 is a table showing the field configuration of the scattered light intensity theoretical value table 402. As shown in FIG.
Scattered light intensity theoretical value table 402 includes first wavelength first scattered light intensity field, first wavelength second scattered light intensity field, second wavelength first scattered light intensity field, second wavelength second scattered light intensity field, refraction It has a rate field, a standard deviation field, an average particle size field, and a particle number field.

The first wavelength first scattered light intensity field stores the theoretical value of the first wavelength first scattered light intensity (I _1λ1 ). The theoretical value of the first wavelength second scattered light intensity (I _2λ1 ) is stored in the first wavelength second scattered light intensity field. The second wavelength first scattered light intensity field stores the theoretical value of the second wavelength first scattered light intensity (I _1λ2 ). The second wavelength second scattered light intensity (I _2λ2 ) theoretical value is stored in the second wavelength second scattered light intensity field.
That is, the fields of these scattered light intensity theoretical values are the same as the data of the same names output by the first polarization camera 111 and the second polarization camera 113, respectively, and the theoretical values of the particle group assumed by the preliminary calculation processing described later. (scalar value) is stored.

The refractive index field stores a refractive index (scalar value) of an assumed particle group calculated by a preliminary calculation process to be described later. The standard deviation field stores the standard deviation (scalar value) of an assumed particle group calculated by a preliminary calculation process described later.
The average particle size field stores the average particle size (scalar value) of the assumed particle group calculated by the preliminary calculation process described later. The particle number field stores the number of particles (scalar value) of an assumed particle group calculated by a preliminary calculation process described later.

[Particle swarm model]
FIG. 6 is a graph showing a particle group model represented by records recorded in the theoretical scattered light intensity value table 402 .
Various studies have shown that a particle group of fine particles with dispersed particle diameters, which is generated due to natural phenomena, roughly matches a Gaussian curve with the horizontal axis as a logarithmic scale, as shown in FIG. Are known. In FIG. 6, the horizontal axis is the particle size on a logarithmic scale, and the vertical axis is the number of particles (appearance frequency).

A Gaussian curve, or normal distribution, is uniquely defined by its mean and standard deviation. Therefore, four parameters of average particle size, standard deviation, number, and refractive index are determined, the wavelength of the violet laser output by the first light source 104, the wavelength of the blue laser output by the second light source 105, the first polarization camera 111 and By giving the angle θ with respect to the optical axis at which the second polarization camera 113 is installed and performing calculations, the first wavelength first scattered light intensity (I _1λ1 ), the first wavelength second scattered light intensity (I _2λ1 ), Theoretical values of the second wavelength first scattered light intensity (I _1λ2 ) and the second wavelength second scattered light intensity (I _2λ2 ) can be calculated.

That is, the first wavelength first scattered light intensity (I _1λ1 ), the first wavelength second scattered light intensity (I _2λ1 ), the second wavelength first scattered light intensity (I _1λ2 ) and the second wavelength second scattered light intensity ( The theoretical value of I _2λ2 ) is a search key for searching refractive index, standard deviation, average particle size, and particle number. The degree of similarity between these theoretical values, which serve as search keys, and the values actually measured by the polarization camera is calculated, and the most similar record is estimated as one that roughly matches the measured particle group parameters.
In calculating the degree of similarity, the distance between the theoretical value and the measured value is calculated. That is, the minimum distance value calculator 401 calculates the distance DS by adding the square of the difference for each parameter, and searches for the record with the smallest value of the distance DS, as shown below.

Distance DS=
(First wavelength first scattered light intensity theoretical value - measured first wavelength first scattered light intensity data) ² +
(First wavelength second scattered light intensity theoretical value - measured first wavelength second scattered light intensity data) ² +
(Second wavelength first scattered light intensity theoretical value - measured second wavelength first scattered light intensity data) ² +
(Second wavelength second scattered light intensity theoretical value - measured second wavelength second scattered light intensity data) ²

[Particle size and polarization ratio]
FIG. 7 is a graph showing the relationship between the average particle diameter of a particle group and the polarization ratio for light of a certain wavelength. The solid line graphs in FIGS. 7 and 8 correspond to the blue laser light, that is, the second light, and the dotted line graph in FIG. 8, which will be described later, corresponds to the purple laser light, that is, the first light.
If the standard deviation is different, the polarization ratio will be completely different even if the particles have the same average particle size. For this reason, with only a single light, different particle sizes correspond to a certain polarization ratio, so the particle group cannot be specified.

FIG. 8 is a graph showing the relationship between the particle size of the particle group and the polarization ratio for light of two wavelengths.
Therefore, when the relationship between the particle size of the particle group and the polarization ratio is plotted on a graph for light of two different wavelengths, even if different particle sizes correspond to a certain polarization ratio, the different wavelengths By superimposing on the graph of , it can be estimated that the value with the smallest particle size error is the target particle size.

The graphs shown in FIGS. 7 and 8 calculate the theoretical scattered light intensity by the following formula. In the following formula, f is Mie's scattering theory formula, λ is the incident light wavelength, θ is the scattering angle, τ _λ is the exposure time, m is the complex refractive index, σ _g is the geometric standard deviation, and D _g is the geometric is the average particle size, C _λ is the optical constant, and n is the number of particles.
λ, θ, τ _λ are default values and m, σ _g , D _g , C _λ , n are unknowns.
λ ₁ is the first light and λ ₂ is the second light.

Of the above equations, dividing the second equation by the first equation, or dividing the fourth equation by the third equation eliminates τ _λ , C _λ , and n. This ratio is called the polarization ratio. Compared to using the above equation as it is, the number of variables is reduced, and it can also be used to calculate m, σ _g and D _g . However, in the case of particles such as soot particles having a size of several nanometers to several tens of nanometers, there is a problem that the change in the polarization ratio is very small when the average particle size is changed, making measurement difficult.

A single particle having a certain particle diameter D outputs scattered light with a predetermined intensity at a scattering angle θ with a complex refractive index m and an optical constant _Cλ for a certain incident light wavelength λ. Since there is more than one particle, the intensity of scattered light is cumulatively added by the number of particles. In addition, since the particle diameter is not limited to one, it is necessary to perform similar calculations for particles with different particle diameters. The particle size appearance frequency of the particles generally follows a normal distribution on a logarithmic scale.
If the mean particle size, the standard deviation of the particle size, and the number of particles are known, the intensity of the scattered light output by the particle group can be calculated.

Therefore, while fixing the incident light wavelength λ, the scattering angle θ, and the exposure time τ _λ in advance, while varying the complex refractive index m, the geometric standard deviation σ _g , the geometric mean particle size D _g , and the optical constant C _λ , , theoretical value of first scattered light intensity for first wavelength (I _1λ1 ), theoretical value for second scattered light intensity for first wavelength (I _2λ1 ), theoretical value for first scattered light intensity for second wavelength (I _1λ2 ), second wavelength first Calculating the theoretical two-scattered light intensity value (I _2λ2 ) is a preliminary calculation process. A scattered light intensity theoretical value table 402 is a table in which the calculation results of the preliminary calculation processing are recorded.

In the preliminary calculation process, the scattering angle θ is set to an appropriate value. Therefore, when the particle swarm measuring apparatus 101 actually performs measurement, the first polarizing camera 111 and the second polarizing camera 113 must be arranged with a scattering angle of ±θ with respect to the object to be measured.

[experiment]
FIG. 9 is a graph of experimental results of an experiment for measuring flame soot using the conventional PAMS method and the particle group measuring device 101 according to the embodiment of the present invention. The form of the graph is almost the same as that of FIG. 6, the horizontal axis is the particle size on a logarithmic scale, and the vertical axis is the normalized particle density (appearance frequency).

In the experiment, the butane gas flame 102 was used as the measurement target.
The PAMS method, which is a conventional technology, is an abbreviation for Portable aerosol mobility spectrometer, and the particles of the generation source are directly collected from the collection port opened on the side of the pipe, and after being classified by sieving, the number of particles of each particle size is calculated. is a method of counting Since the soot in the flame is the object of measurement, nitrogen gas is passed through the pipe to cool and dilute the soot in order to freeze the oxidation reaction caused by the flame and to suppress the cohesion of the soot particles. Taken.
Looking at FIG. 9, it can be seen that the particle size at the vertex P901 of the graph of the actual measurement result by the PAMS method and the vertex P902 of the graph of the estimated calculation result of the particle group measuring apparatus 101 according to the embodiment of the present invention are approximately similar. .

The embodiment of the present invention discloses the particle swarm measuring device 101 .
The particle swarm measuring device 101 creates a scattered light intensity theoretical value table 402 in advance by preliminary calculation processing. Then, the first polarizing camera 111 and the second polarizing camera 113 are installed at the positions of the scattering angles ±θ determined at the time of the preliminary calculation processing.

Distance minimum value calculator 401 calculates the measured first wavelength first scattered light intensity (I _1λ1 ), the measured first wavelength second scattered light intensity (I _2λ1 ) output from the first polarization camera 111, and the second polarization camera Identify the record of the theoretical scattered light intensity table 402 that has the highest similarity to the measured second wavelength first scattered light intensity (I _1λ2 ) and the measured second wavelength second scattered light intensity (I _2λ2 ) output from 113 and outputs the refractive index m, the standard deviation σ _g , the average particle size D _g , and the number of particles n.
The particle swarm measuring device 101 can estimate and calculate the refractive index m, standard deviation σ _g , average particle diameter D _g , and particle number n of the particle swarm in a non-contact and extremely short time.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and other modifications and applications can be made without departing from the gist of the present invention described in the scope of claims. include.

DESCRIPTION OF SYMBOLS 101... Particle group measuring apparatus, 102... Flame, 104... First light source, 105... Second light source, 106... Light combiner, 107... Polarizing filter, 108... Convex lens, 110... Beam stop, 111... First polarization camera, 112 First color filter 113 Second polarizing camera 114 Second color filter 115 Information processor 201 Polarizing camera 202 Micro polarizing plate 301 Bus 302 CPU 303 ROM 304 RAM 305 Display unit 306 Operation unit 307 Non-volatile storage 308 Serial interface 401 Minimum distance calculation unit 402 Scattered light intensity theoretical value table 403 Exposure control unit

Claims (4)

a first light source that irradiates a first light having a first wavelength onto an optical path passing through the object to be measured;
a second light source that irradiates the optical path with second light having a second wavelength different from the first wavelength;
The light from the first light source is received from the optical path and placed at a predetermined scattering angle +θ in a direction parallel to the observation plane including the optical path with the measurement object as the center, and the light is first scattered. a first polarization camera that outputs light intensity data;
receiving the light of the second light source, which is arranged at a predetermined scattering angle −θ in a direction parallel to the observation plane from the optical path, centering on the measurement target, to obtain a second scattered light; a second polarization camera that outputs intensity data;
A light intensity field that stores the theoretical value of the scattered light intensity, a refractive index field that stores the refractive index, a standard deviation field that stores the standard deviation, and an average particle size for the assumed particle group. a scattered light intensity theoretical value table having an average particle size field and a particle number field in which the number of particles is stored;
a distance minimum value calculator that compares the scattered light intensity data with the theoretical scattered light intensity value and outputs the refractive index, standard deviation, average particle size, and number of particles from the record with the highest degree of similarity. Group measuring device. The first scattered light intensity data output by the first polarization camera includes measured first wavelength first scattered light intensity data, which is a vertical polarization intensity value derived from the first light, and Measured first wavelength second scattered light intensity data, which is a laterally polarized intensity value derived from
The second scattered light intensity data output by the second polarization camera includes measured second wavelength first scattered light intensity data, which is a vertical polarization intensity value derived from the second light, and Measured second wavelength second scattered light intensity data, which is a laterally polarized intensity value derived from
The particle swarm measuring device according to claim 1. The light intensity field is
a first wavelength first scattered light intensity field in which a first wavelength first scattered light intensity theoretical value corresponding to the measured first wavelength first scattered light intensity data is stored;
a first wavelength second scattered light intensity field in which a first wavelength second scattered light intensity theoretical value corresponding to the measured first wavelength second scattered light intensity data is stored;
a second wavelength first scattered light intensity field in which a second wavelength first scattered light intensity theoretical value corresponding to the measured second wavelength first scattered light intensity data is stored;
a second wavelength second scattered light intensity field in which a second wavelength second scattered light intensity theoretical value corresponding to the measured second wavelength second scattered light intensity data is stored;
The distance minimum value calculation unit is configured to calculate the measurement first wavelength first scattered light intensity data, the measurement first wavelength second scattered light intensity data, the measurement second wavelength first scattered light intensity data, and the measurement second wavelength first scattered light intensity data. In response to the input of the two scattered light intensity data, the first wavelength first theoretical scattered light intensity value, the first wavelength second theoretical scattered light intensity value, the second wavelength first theoretical value of the scattered light intensity theoretical value table A record having the highest degree of similarity to the theoretical value of scattered light intensity and the theoretical value of second wavelength second scattered light intensity is specified, and the refractive index, the standard deviation, the average particle size, and the number of particles are determined from the specified record. which outputs
The particle swarm measuring device according to claim 2. Furthermore,
a polarizing filter disposed between the first light source and the second light source and the measurement target, and passing the first light and the second light polarized at an angle of 45° to the observation plane; The particle swarm measuring device according to claim 3, comprising:

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