Particle detection device and program

Abstract

To improve particle detection precision at a low cost.SOLUTION: A particle detection device 100 comprises a detector 10 which detects the particle size of a particle 1 in fluid in a passage 60, the detector 10 has a processing part 40 which detects the particle size of the particle 1 from image data 70 output by receiving transmitted light, transmitted through the passage 60, of light from an irradiation part 20 irradiating the passage 60 with the light, and the processing part 40 acquires the shape and luminance of a diffraction pattern, formed as the light from the irradiation part 20 is diffracted by the surface of the particle 1, as determination information from the image data 70, and detects the particle size of the particle 1 from the determination information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a particle detection device and a program.

Background Art

[0002] Patent Document 1 discloses a stain detection device including a light source that irradiates light onto a liquid, an image acquisition unit that is disposed at a position facing the light source and acquires a detection image obtained by imaging the light transmitted through the liquid, and a detection unit that detects the particle size or the number of particles of contaminants contained in the liquid based on the detection image. The detection unit detects the particle size of the contaminants from the number of pixels of a shadow (black dots) imaged by blocking the light from the light source by the particles of the contaminants in the detection image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a particle detection device (stain detection device) as described in Patent Document 1, when a general light source is used, if the detection target is very small particles, the light from the light source diffracts on the surface of the particles. Therefore, in the imaged image data, the region corresponding to the particles does not become a shadow, but a diffraction pattern occurs. As a result, the detection accuracy of the particles deteriorates. In order to improve the detection accuracy of the particles, for example, it is conceivable to use a light source at the electron microscope level, but in this case, the device becomes very expensive.

[0005] The present invention has been made in view of the above problems, and an object thereof is to improve the detection accuracy of particles at low cost.

Means for Solving the Problems

[0006] The present invention relates to a particle detection device, comprising a processing unit that detects the particle size of particles contained in a liquid from image data generated based on the intensity of transmitted light that has passed through the liquid among the light emitted from an irradiation unit that irradiates light toward the liquid. The processing unit acquires, as discrimination information, the shape and luminance of a diffraction pattern generated by diffraction of the light from the irradiation unit on the surface of the particle in the image data, and calculates the particle size from the discrimination information.

[0007] In this invention, even when the light from the irradiation unit diffracts on the surface of a small particle to be detected, the processing unit calculates the particle size from two pieces of information, namely, the shape and luminance of the diffraction pattern. Specifically, the position of the particle (the distance between the particle and the irradiation unit) is detected from the luminance of the diffraction pattern, and the particle size is calculated in conjunction with the shape of the diffraction pattern. Thereby, the particle size can be accurately calculated. Therefore, the detection accuracy of particles can be improved at low cost using a general irradiation unit.

[0008] Further, the present invention is characterized in that the irradiation unit includes a light source that irradiates diffused light and a diaphragm through which a part of the diffused light irradiated from the light source passes.

[0009] In this invention, by irradiating the diffused light emitted from the light source as a point light source toward the passage through the diaphragm, the diffraction pattern reflected in the image data becomes clear, and the detection accuracy of particles can be improved.

[0010] Further, the present invention is characterized in that the irradiation unit includes a point light source that irradiates diffused light toward the liquid and a lens provided between the point light source and the liquid that collimates the diffused light irradiated by the point light source and emits it.

[0011] In this invention, when a general irradiation unit is used, an improvement in the detection accuracy of particles can be realized at low cost.

[0012] The present invention also relates to a program for causing a computer to execute a process of detecting the particle size of particles contained in a liquid based on the intensity of transmitted light that has passed through the liquid among the light irradiated by the irradiation unit toward the liquid. The computer is caused to acquire, as discrimination information, the shape and luminance of a diffraction pattern generated by diffraction of the light from the irradiation unit on the surface of the particles in the image data, and to calculate the particle size from the discrimination information.

[0013] In this invention, even when the detection target is small particles and the light from the irradiation unit is diffracted on the surface of the particles, the processing unit detects the particle size from two pieces of information, the shape and luminance of the diffraction pattern. Specifically, the position of the particles (the distance between the particles and the irradiation unit) is detected from the luminance of the diffraction pattern, and the particle size is detected in combination with the shape of the diffraction pattern. Thereby, the particle size can be accurately detected. Therefore, the detection accuracy of particles can be improved at low cost using a general irradiation unit.

Effects of the Invention

[0014] According to the present invention, the detection accuracy of particles can be improved at low cost.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0016] With reference to the drawings, the particle detection device 100 according to an embodiment of the present invention will be described.

[0017] The particle detection device 100 is provided, for example, between joints that connect a pipe (not shown) for supplying and discharging hydraulic oil to a hydraulic machine (not shown), and detects particles 1 that are foreign substances in the hydraulic oil. In the present embodiment, the particle detection device 100 detects the particle size as a parameter of the particles 1 in the hydraulic oil. Based on the detection result of the particle detection device 100, the state such as the deterioration of the hydraulic oil is monitored. Note that the particle detection device 100 may detect the particles 1 in fluids such as working water and compressed air other than the hydraulic oil. Further, the particle detection device 100 may be provided in a particle detection passage branched from a pipe for supplying and discharging the hydraulic oil to detect the particles 1.

[0018] As shown in FIG. 1, the particle detection device 100 includes a detector 10 that detects the particle size of the particles 1 contained in the hydraulic oil in the passage 60. Further, the detector 10 has a processing unit 40 that calculates the particle size of the particles 1 from the image data 70 (see FIG. 3) output by receiving the transmitted light that has passed through the passage 60 (hydraulic oil) among the light irradiated from the irradiation unit 20 that irradiates light toward the passage 60 (hydraulic oil). The image data 70 is generated based on the intensity of the transmitted light and is output to the processing unit 40 by an image sensor 30 as an image acquisition unit. The image sensor 30 receives the transmitted light that has passed through the passage 60 among the light from the irradiation unit 20 and outputs the image data 70. Note that the particle detection device 100 is not limited to detecting the particle size of the particles 1 contained in the hydraulic oil in the passage 60, and may be any device that detects the particle size of the particles 1 contained in a liquid. For example, the particle detection device 100 may detect the particle size of the particles 1 contained in a sampled liquid placed in a test tube or the like.

[0019] The passage 60 is provided to relay between the oil passages that supply and discharge hydraulic oil to and from the hydraulic machine. In the present embodiment, the passage 60 is provided to extend in the vertical direction, and the horizontal dimension along the optical axis of the irradiation unit 20 is uniform. In the passage 60, transmission windows 65 and 66 for transmitting the light from the irradiation unit 20 are provided to face the irradiation unit 20 and the image sensor 30, respectively. The transmission windows 65 and 66 are formed of a light-transmissive material such as glass, synthetic quartz, or sapphire, for example. The passage 60 is not limited to the configuration that extends in the vertical direction, and may be provided to be inclined with respect to the vertical direction or may be provided to extend in the horizontal direction. Even in this case, the irradiation unit 20 and the image sensor 30 are provided in the positional relationship corresponding to FIG. 1.

[0020] The irradiation unit 20 is provided outside the passage 60. In the present embodiment, the irradiation unit 20 is a point light source that irradiates diffused light toward the passage 60. As shown in FIG. 2, the irradiation unit 20 includes a laser 21 as a light source that irradiates diffused light, and a diaphragm 22 through which a part of the diffused light irradiated from the laser 21 passes. The laser 21 is a blue laser, but may be a laser of another color or a light source that irradiates diffused light other than a laser. Since the irradiation unit 20 is formed by the laser 21 and the diaphragm 22 in this way, in the irradiation unit 20, the diffused light that has passed through the diaphragm 22 behaves as a point light source. The smaller the opening area of the diaphragm 22 is, the more the particles 1 are irradiated with light from different angles within a narrow range, so that the image data 70 becomes clearer. The smaller the particles 1 are, the more preferably the opening area of the diaphragm 22 is reduced. Further, when the diffused light passes through the diaphragm 22, the irradiation range is widened by diffraction. The irradiation range of the diffused light widened by diffraction is preferably larger than the irradiation range of the light required from the installation position of the image sensor 30 and the size (resolution) of the image data 70. Note that the irradiation unit 20 is not limited to the configuration having the laser 21 and the diaphragm 22, and may be a configuration in which a single point light source irradiates diffused light without providing the diaphragm 22. The diffused light irradiated by the irradiation unit 20 is incident on the passage 60 perpendicularly, passes through the passage 60, and is incident on the image sensor 30.

[0021] The image sensor 30 is provided outside the passage 60 so as to face the irradiation unit 20 with the passage 60 interposed therebetween. For the image sensor 30, for example, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used. The image sensor 30 receives the light irradiated from the irradiation unit 20 and transmitted through the passage 60, and outputs the image data 70 captured at predetermined time intervals to the processing unit 40.

[0022] As shown by the dotted line in FIG. 1, when the particle 1 in the hydraulic oil passes through the optical path of the irradiation unit 20 (in other words, when the particle 1 passes between the irradiation unit 20 and the image sensor 30), the light from the irradiation unit 20 diffracts on the surface of the particle 1. Therefore, a diffraction pattern (hereinafter, also simply referred to as "diffraction pattern") generated by the light from the irradiation unit 20 diffracting on the surface of the particle 1 is projected onto the image sensor 30. Note that the diffraction pattern includes the shadow of the particle 1 where the light from the irradiation unit 20 is substantially blocked. The image sensor 30 outputs these as the image data 70 to the processing unit 40.

[0023] FIG. 3 shows a schematic diagram of the diffraction pattern under each condition of particle 1. Note that for those at a far distance from the irradiation unit 20, in FIG. 3, in order to make the diffraction pattern easier to see, a dotted line is attached to the contour of the dark part of the diffraction pattern. As shown in FIG. 3, the shape of the diffraction pattern changes depending on the particle size of particle 1 (specifically, the particle size of particle 1 with respect to the irradiation area of the light irradiated by the irradiation unit 20). When the particle size of particle 1 is large, diffraction hardly occurs, and a shadow of particle 1 where the light from the irradiation unit 20 is substantially blocked is projected. When the particle size of particle 1 is small, diffraction occurs, and a circular or annular diffraction pattern is projected. In the present embodiment, since the passage 60 has a width for a plurality of particles 1, the distance between particle 1 and the irradiation unit 20 and the distance between particle 1 and the image sensor 30 change depending on the position where particle 1 flows in the passage 60. As shown in FIG. 3, even if the particle size of particle 1 is the same, if the distance between particle 1 and the irradiation unit 20 is different, the shape and luminance of the diffraction pattern (specifically, the darkness of the dark part of the diffraction pattern) are different. Specifically, the dark part of the diffraction pattern becomes darker as the distance from the irradiation unit 20 of particle 1 is closer, and becomes lighter as the distance from the irradiation unit 20 of particle 1 is farther. This is because the light irradiated from the irradiation unit 20 is diffused light, and the closer particle 1 and the irradiation unit 20 are, the more light quantity is irradiated to particle 1, so the dark part of the diffraction pattern becomes darker, and the farther particle 1 and the irradiation unit 20 are, the less light quantity is irradiated to particle 1, so the dark part of the diffraction pattern becomes lighter. Note that when the distance from the irradiation unit 20 of particle 1 becomes farther, the outer diameter of the diffraction pattern becomes larger.

[0024] Also, the shape of the diffraction pattern may be the same depending on the distance from the irradiation unit 20 even if the particle size of particle 1 is different. Specifically, for particle 1 with a small particle size and a close distance from the irradiation unit 20 (A shown in FIG. 3) and particle 1 with a large particle size and a far distance from the irradiation unit 20 (B shown in FIG. 3), the shape of the diffraction pattern is substantially the same. However, both the shape and luminance of the diffraction pattern will not be the same depending on the distance from the irradiation unit 20 when the particle size of particle 1 is different. Therefore, by using the two pieces of information of the shape and luminance of the diffraction pattern, the particle size of particle 1 can be accurately detected.

[0025] The processing unit 40 is composed of a microcomputer equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an I / O interface (Input / Output interface). The RAM stores data in the processing of the CPU, the ROM stores in advance the control program of the CPU, etc., and the I / O interface is used for input / output of information with devices connected to the processing unit 40. Note that the processing unit 40 may be composed of a plurality of microcomputers. In the processing unit 40, the CPU executes a program stored in advance in the ROM or the like to execute each of the processes described below.

[0026] In the image data 70 output from the image sensor 30, the processing unit 40 acquires the shape and luminance of the diffraction pattern as discrimination information. From the acquired discrimination information, the processing unit 40 detects the particle size of the particle 1 (specifically, the particle size of the particle 1 that has passed through the optical path of the irradiation unit 20). The image data 70 is, in other words, data indicating the intensity of the light received by the image sensor 30, and the processing unit 40 detects the particle size of the particle 1 from the intensity of the light indicated by the image data 70.

[0027] Next, a method for acquiring discrimination information by the processing unit 40 will be described.

[0028] First, the processing unit 40 converts the image data 70 of the transmitted light into grayscale and performs background difference processing as shown in FIG. 4. In the background difference processing, specifically, the output image data 70b from the second image data 70b onwards is compared with the image data 70a output immediately before the image data 70b (for example, the second image data 70b is compared with the first image data 70a), and a background difference image 71 is acquired. Thereby, it is possible to prevent the dark portions of the image data 70 caused by foreign matters 3 such as scratches and dirt other than the particle 1 reflected in the image data 70 and deterioration of the irradiation unit 20 from being detected as the particle 1. Note that in the background difference processing, one image stored in advance in the processing unit 40 may be used as a reference image to be compared with the image data 70. Also, in the processing by the processing unit 40, the background difference processing is not an essential process and may be omitted.

[0029] Thereafter, the processing unit 40 performs a Hough transform process on the acquired background difference image 71 to acquire the coordinates of the center O of the particle 1 and the size of the particle 1 in the background difference image 71. Further, as shown in FIG. 5(b), the luminance from the center O of the particle 1 to the outer peripheral edge in a predetermined radial direction (the dotted line portion shown in FIG. 5(a)) is acquired in relation to the distance from the center O. In the diffraction pattern shown in FIGS. 4 and 5(a), as shown in FIG. 5(b), the luminance is high at the center O of the particle 1, and as the distance from the center O increases, the luminance decreases in the dark part of the diffraction pattern and then increases again, and information is obtained that the luminance decreases at the outer peripheral edge of the particle 1. From the positions (distances from the center O) of the high-luminance peak and the low-luminance peak, the shape of the diffraction pattern is acquired, and from the numerical values of the luminance of each of the high-luminance peak and the low-luminance peak, the luminance of the diffraction pattern is acquired. In other words, the "shape of the diffraction pattern" in the discrimination information is the value of the distance from the center O of each of the high-luminance peak and the low-luminance peak. In this way, the processing unit 40 calculates the shape and luminance of the diffraction pattern and acquires them as discrimination information.

[0030] Next, a method for the processing unit 40 to detect (calculate) the particle size of the particle 1 from the discrimination information will be described.

[0031] In the processing unit 40, information on the shape and luminance of the diffraction pattern corresponding to the diffraction pattern at each particle size of the particle 1 and the distance from the irradiation unit 20 as shown in FIG. 3 is stored in advance as a map within a numerical range. The map is obtained experimentally, for example. The processing unit 40 calculates the particle size of the particle 1 by searching the map for the information on the shape and luminance of the diffraction pattern whose acquired discrimination information is included in the numerical range.

[0032] As described above, the program stored in the processing unit 40 is a program for causing a computer (processing unit 40) to execute a process of detecting the particle size of particles 1 contained in the hydraulic oil based on the intensity of transmitted light that has passed through the passage 60 (hydraulic oil) among the light irradiated by the irradiation unit 20 toward the passage 60 (hydraulic oil). The computer is caused to acquire, as discrimination information, the shape and luminance of a diffraction pattern generated by diffraction of the light from the irradiation unit 20 on the surface of the particle 1 in the image data 70, and to calculate the particle size of the particle 1 from the discrimination information.

[0033] Here, in a particle detection device that detects the particle size from the number of pixels of a shadow (black dot) captured by blocking the light of a light source with a particle, when a general light source is used, if the detection target is a very small particle of, for example, 100 μm or less, the light from the light source diffracts on the surface of the particle. Therefore, in the captured image data, the region corresponding to the particle does not become a shadow, and a diffraction pattern is generated. As a result, the detection accuracy of the particle deteriorates. In order to improve the detection accuracy of the particle, for example, it is conceivable to use a light source and an image acquisition unit with a small irradiation area at the electron microscope level, but in this case, the device becomes extremely expensive.

[0034] On the other hand, in the particle detection device 100, even if the light from the irradiation unit 20 diffracts on the surface of the small particle 1 that is the detection target, the processing unit 40 calculates the particle size of the particle 1 from the two pieces of information on the shape and luminance of the diffraction pattern. Specifically, the position of the particle 1 (the distance between the particle 1 and the irradiation unit 20) is detected from the luminance of the diffraction pattern, and the particle size of the particle 1 is calculated in combination with the shape of the diffraction pattern. Although the shape of the diffraction pattern may be the same depending on the position of the particle 1 even for particles 1 with different particle sizes, the particle size of the particle 1 can be accurately calculated by detecting the position of the particle 1 from the luminance of the diffraction pattern (specifically, the darkness of the dark part of the diffraction pattern). Therefore, the detection accuracy of the particle 1 can be improved at low cost using a general irradiation unit 20 and image sensor 30.

[0035] In addition, in the particle detection device 100 of the present embodiment, the irradiation unit 20 includes a laser 21 as a light source that irradiates diffused light and an aperture 22. By irradiating the diffused light emitted from the laser 21 as a point light source toward the passage through the aperture 22, it is possible to irradiate the particle 1 with diffused light having a large amount of light, and the diffraction pattern reflected in the image data 70 becomes clear. Therefore, the detection accuracy of the particle 1 can be improved.

[0036] In addition, in the particle detection device 100 of the present embodiment, the minimum particle size of the particle 1 is assumed from the material of the particle 1 to be detected, etc., and the irradiation area for the irradiation unit 20 to irradiate the particle 1 is set to be the same as the minimum particle size of the particle 1 to be detected. As a result, the diffraction pattern reflected in the image data 70 becomes clear, and the detection accuracy of the particle 1 can be improved.

[0037] In addition, in the particle detection device 100 of the present embodiment, the irradiation unit 20 includes a laser 21 that is a blue laser and an aperture 22. In this irradiation unit 20, light is slightly diffracted even when passing through the aperture 22. However, since the laser 21 is a blue laser with high linearity, it is difficult for the light passing through the aperture 22 to be diffracted, so the detection accuracy of the particle 1 can be improved.

[0038] According to the above-described embodiment, the following operational effects are achieved.

[0039] In the particle detection device 100, even when the light from the irradiation unit 20 diffracts on the surface of the small particle 1 that is the detection target, the processing unit 40 calculates the particle size of the particle 1 from two pieces of information, the shape and luminance of the diffraction pattern. Although the shape of the diffraction pattern may be the same depending on the position of the particle 1 (the distance between the particle 1 and the irradiation unit 20) even for particles 1 with different particle sizes, by using the shape and luminance of the diffraction pattern, the particle size of the particle 1 can be calculated while considering the position of the particle 1. Therefore, the detection accuracy of the particle 1 can be improved at low cost using a general irradiation unit 20 and image sensor 30.

[0040] In addition, the following modification examples are also within the scope of the present invention, and it is also possible to combine the configurations shown in the modification examples with the configurations described in the above-described embodiments, or to combine the configurations described in the following different modification examples with each other.

[0041] <Modification Example 1> In the above-described embodiment, the irradiation unit 20 irradiates diffused light toward the passage 60 (hydraulic oil). However, the irradiation unit 20 is not limited to this, and may irradiate parallel light toward the passage 60 (hydraulic oil). Specifically, as shown in FIG. 6, the irradiation unit 20 may include a point light source (laser 21, aperture 22) that irradiates diffused light toward the passage 60 (hydraulic oil), and a lens 25 that is provided between the point light source and the passage 60 (hydraulic oil) and emits the diffused light irradiated by the point light source as parallel light. The diffused light irradiated by the irradiation unit 20 becomes parallel light by passing through the lens 25, enters the passage 60 perpendicularly, passes through the passage 60, and enters the image sensor 30. In this configuration, the dark portion of the diffraction pattern becomes thinner as the distance from the irradiation unit 20 of the particle 1 is closer, and becomes darker as the distance from the irradiation unit 20 of the particle 1 is farther. That is, it is the opposite of the case of the diffused light shown in FIG. 3. This is because the light irradiated from the irradiation unit 20 is parallel light, and the closer the particle 1 and the irradiation unit 20 are (in other words, the farther the particle 1 and the image sensor 30 are), the more the diffracted light is attenuated by the fluid flowing through the passage 60 or the like, and the amount of light incident on the image sensor 30 decreases, so that the dark portion of the diffraction pattern becomes thinner. Also, the farther the particle 1 and the irradiation unit 20 are (in other words, the closer the particle 1 and the image sensor 30 are), the less the diffracted light is attenuated by the fluid flowing through the passage 60 or the like, the amount of light incident on the image sensor 30 increases, and the dark portion of the diffraction pattern becomes darker. In this configuration, in the detector 10 using a general irradiation unit 20 and lens 25, it is possible to inexpensively improve the detection accuracy of the particle 1. Note that a configuration may be adopted in which the irradiation unit 20 has a light source that irradiates parallel light without providing the lens 25.

[0042] <Modification Example 2> In the above-described embodiment, the particle detection device 100 acquires the luminance in the linear range between the center O and the outer periphery of the particle 1, acquires the shape of the diffraction pattern from the positions of the peak with high luminance and the peak with low luminance, and acquires the luminance of the diffraction pattern from the numerical values of the luminance of each of the peak with high luminance and the peak with low luminance. However, the method for acquiring the shape and luminance of the diffraction pattern is not limited to the above. For example, the particle detection device 100 may acquire the luminance in a plurality of linear ranges between the center O and the outer periphery of the particle 1 respectively, and acquire the shape of the diffraction pattern from the average of the positions of the peak with high luminance and the average of the positions of the peak with low luminance. Also, the luminance of the diffraction pattern may be acquired from the numerical value of the luminance of either the peak with high luminance or the peak with low luminance, or the ratio between the two, and the particle size of the particle 1 may be detected.

[0043] The configuration, operation, and effects of the embodiment of the present invention configured as described above will be collectively described.

[0044] The particle detection device 100 includes a processing unit 40 that detects the particle size of the particle 1 from image data 70 generated based on the intensity of transmitted light that has passed through the liquid among the light from the irradiation unit 20 that irradiates light toward the liquid. The processing unit 40 acquires, as discrimination information, the shape and luminance of the diffraction pattern generated by the light from the irradiation unit 20 diffracting on the surface of the particle 1 in the image data 70, and calculates the particle size of the particle 1 from the discrimination information.

[0045] In this configuration, even when the light from the irradiation unit 20 diffracts on the surface of the small particle 1 that is the detection target, the processing unit 40 calculates the particle size of the particle 1 from the two pieces of information of the shape and luminance of the diffraction pattern. Specifically, the position of the particle 1 (the distance between the particle 1 and the irradiation unit 20) is detected from the luminance of the diffraction pattern, and the particle size of the particle 1 is calculated in combination with the shape of the diffraction pattern. Thereby, the particle size of the particle 1 can be accurately calculated. Therefore, the detection accuracy of the particle 1 can be improved at low cost using a general irradiation unit 20.

[0046] Further, the irradiation unit 20 includes a laser 21 as a light source that irradiates diffused light, and a diaphragm 22 through which a part of the diffused light irradiated from the laser 21 passes.

[0047] In this configuration, by irradiating the diffused light emitted from the laser 21 as a point light source toward the passage 60 through the aperture 22, the diffraction pattern reflected in the image data 70 becomes clear, and the detection accuracy of the particles 1 can be improved.

[0048] Further, the irradiation unit 20 includes a point light source (laser 21, aperture 22) that irradiates diffused light toward the passage 60, and a lens 25 that is provided between the point light source and the liquid and emits the diffused light irradiated by the point light source as parallel light.

[0049] In this configuration, when a general irradiation unit 20 is used, the detection accuracy of the particles 1 can be improved at low cost.

[0050] Further, a program for causing a computer (processing unit 40) to execute a process of detecting the particle size of the particles 1 contained in the liquid from the image data 70 generated based on the intensity of the transmitted light that has passed through the liquid among the light irradiated by the irradiation unit 20 toward the liquid causes the shape and luminance of the diffraction pattern generated by the light from the irradiation unit 20 diffracting on the surface of the particles 1 to be acquired as discrimination information in the image data 70, and calculates the particle size of the particles 1 from the discrimination information.

[0051] In this configuration, even when the light from the irradiation unit 20 diffracts on the surface of the small particles 1 to be detected, the particle size of the particles 1 is calculated from the two pieces of information of the shape and luminance of the diffraction pattern. Specifically, the position of the particles 1 (the distance between the particles 1 and the irradiation unit 20) is detected from the luminance of the diffraction pattern, and the particle size of the particles 1 is calculated in combination with the shape of the diffraction pattern. Thereby, the particle size of the particles 1 can be accurately calculated. Therefore, the detection accuracy of the particles 1 can be improved at low cost using a general irradiation unit 20.

[0052] As described above, the embodiments of the present invention have been described. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Explanation of reference numerals

[0053] 1... particle, 10... detector, 20... irradiation unit, 21... laser (light source), 22... aperture, 25... lens, 40... processing unit, 70... image data, 100... particle detection device

Claims

1. A particle detection device comprising a processing unit that detects the particle size of particles contained in a liquid from image data generated based on the intensity of transmitted light that has passed through the liquid among the light from an irradiation unit that irradiates light toward the liquid. The processing unit acquires, as discrimination information, the shape and luminance of a diffraction pattern generated by diffraction of the light from the irradiation unit on the surface of the particles in the image data, and calculates the particle size of the particles from the discrimination information.

2. The particle detection device according to claim 1, wherein the irradiation unit includes a light source that irradiates diffused light and a diaphragm through which a part of the diffused light irradiated from the light source passes.

3. The particle detection device according to claim 1, wherein the irradiation unit includes a point light source that irradiates diffused light toward the liquid, and a lens provided between the point light source and the liquid, which collimates the diffused light irradiated by the point light source and emits it.

4. A program for causing a computer to execute a process of detecting the particle size of particles contained in a liquid from image data generated based on the intensity of transmitted light that has passed through the liquid among the light irradiated by an irradiation unit toward the liquid. The program causes the computer to acquire, as discrimination information, the shape and luminance of a diffraction pattern generated by diffraction of the light from the irradiation unit on the surface of the particles in the image data, and to calculate the particle size of the particles from the discrimination information.

Images