Particle group characteristic measuring device and method, particle size distribution measuring device and method, and storage medium

Abstract

A particle group characteristic measuring device measures the characteristics of a particle group composed of multiple particles dispersed in a dispersion medium, that is, the temporal variation of the characteristics of the particle group, including: a shooting unit for shooting the particle group; a particle information extraction unit for processing the captured image captured by the shooting unit to extract information about the particles reflected in the captured image, that is, particle information; a particle group characteristic calculation unit for calculating the particle group characteristics at multiple time points based on the particle information extracted from multiple captured images captured before each time point along a time series, and the particle group characteristic calculation unit calculates the particle group characteristics at each time point based on the particle information extracted from multiple captured images whose shooting time period partially overlaps with the shooting time period of the multiple captured images captured at time points earlier than each time point for calculating the particle group characteristics.

Description

Technical Field

[0001] The present invention relates to a particle group characteristic measuring device, a particle group characteristic measuring method, a program for a particle group characteristic measuring device, a particle size distribution measuring device, and a particle size distribution measuring method for measuring the temporal changes of the characteristics (also called particle group characteristics) of a particle group composed of multiple particles dispersed in a dispersion medium. Background Art

[0002] It is known that the state of a particle group dispersed in a dispersion medium changes over time due to dispersion, aggregation, and other factors. Therefore, when measuring, for example, the particle size distribution of a particle group, there is a need to pre-measure temporal changes in characteristics of the particle group, such as a representative particle size, monitor the state of the particle group, and then perform particle size distribution measurement once the particle group reaches a desired state.

[0003] In the past, when measuring the temporal variation of such particle group characteristics, a laser diffraction and scattering method measuring device was sometimes used (Patent Document 1) to detect the light intensity of diffracted light and scattered light generated by irradiating a laser onto a particle group. However, due to the stability of the laser, this laser diffraction and scattering method requires a blank measurement before the measurement, making it difficult to measure the temporal variation of particle group characteristics for a long period of time.

[0004] Therefore, it is possible to consider using a so-called image analysis device to measure the temporal variation of particle group characteristics. The image analysis device processes an image obtained by photographing a particle group irradiated with light and, for example, extracts information about the particles reflected in the image (also called particle information) to calculate particle group characteristics such as a representative particle size. If a device using this image analysis method is used, blank measurements are not required, and thus the temporal variation of particle group characteristics can be measured for a long period of time.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-207001

[0006] However, in the case of a device using an image analysis method, in order to fully ensure the amount of transmitted light from the sample during shooting, it is necessary to reduce the concentration of particles in the sample, which results in a decrease in the number of particles reflected in one captured image. Therefore, in a device using a conventional image analysis method that processes a captured image and calculates the characteristics of a particle group based on particle information such as the particle size of the particles reflected in the captured image, the statistical error contained in the calculated particle group characteristics becomes larger. In order to solve this problem, it is also possible to consider using the multiple captured images to calculate the particle group characteristics each time the number of captured images required to reduce the statistical error to within the allowable range is obtained. However, in this method, it takes time to obtain the required number of captured images, so there is a problem that the update interval of the particle group characteristics becomes longer and it is difficult to grasp the changes in the particle group characteristics over time. Summary of the Invention

[0007] The present invention is completed in view of the above-mentioned problems, and its main purpose is to provide a particle group characteristic measuring device that measures the temporal changes of particle group characteristics based on captured images. The particle group characteristic measuring device can reduce the statistical errors contained in the calculated particle group characteristics and easily grasp the temporal changes of particle group characteristics.

[0008] That is, the particle group characteristic measuring device of the present invention measures the temporal variation of the particle group characteristic, wherein the particle group characteristic is the characteristic of a particle group composed of a plurality of particles dispersed in a dispersion medium, and the particle group characteristic measuring device includes: a shooting unit for shooting the particle group; a particle information extraction unit for processing the shot image shot by the shooting unit to extract particle information, wherein the particle information is information about the particles reflected in the shot image; and a particle group characteristic calculation unit for calculating the particle group characteristics at the plurality of time points based on the particle information extracted from the plurality of shot images shot before each of the plurality of time points along a time series, and the particle group characteristic calculation unit calculates the particle group characteristics at each time point based on the particle information extracted from the plurality of shot images whose shooting time period partially overlaps with the shooting time period of the plurality of shot images shot at a time point earlier than each time point for calculating the particle group characteristics.

[0009] If such a device is used, since the particle swarm characteristics at each time point are calculated based on the particle information extracted from multiple captured images, the statistical amount of particle information can be increased compared to the case where the calculation is performed based on the particle information extracted from one captured image, and the statistical error contained in the calculated particle swarm characteristics can be reduced. Moreover, the particle swarm characteristics at each time point are calculated based on the particle information extracted from multiple captured images whose shooting time period overlaps with the shooting time period of the multiple captured images used to calculate the particle swarm characteristics at a time point earlier than each time point. That is, the captured images obtained up to the time point earlier than each time point are used as part of the multiple captured images used to calculate the particle swarm characteristics at each time point. Therefore, the time spent on ensuring the number of particle information required to reduce the statistical error to within the allowable range can be shortened, and the particle swarm characteristics at each time point can be calculated in a short time. As a result, the statistical error contained in the calculated particle swarm characteristics can be reduced, and the temporal changes of the particle swarm characteristics can be easily grasped.

[0010] In the particle swarm characteristic measuring device, preferably, the particle swarm characteristic calculation unit calculates the particle swarm characteristics at each time point based on the particle information extracted from multiple captured images that are partially repeated with the multiple captured images used to calculate the particle swarm characteristics at the previous time point at each time point.

[0011] In this way, the particle swarm characteristics at each time point are calculated based on particle information extracted from multiple captured images that partially overlap with the multiple captured images used to calculate the particle swarm characteristics at the previous time point. In other words, the particle swarm characteristics at each time point are calculated by taking into account a portion of the particle information used to calculate the particle swarm characteristics at the previous time point. This reduces the amount of change in the particle swarm characteristics between adjacent time points. Thus, by reducing the amount of change in the particle swarm characteristics between adjacent time points, the particle swarm characteristics at each time point can be smoothed, making it very easy to grasp the changes in the particle swarm characteristics over time.

[0012] In the particle group characteristic measurement device, preferably, the particle group characteristic calculation unit calculates the particle group characteristic at each time point based on a plurality of particle information including the particle information most recently extracted at each time point.

[0013] In this way, the particle swarm characteristics calculated at each time point can be made to reflect the latest state of the particle swarm at each time point.

[0014] As an embodiment of the particle group characteristic calculation unit, there can be mentioned an embodiment in which the particle group characteristic at each time point is calculated based on the particle information extracted from a fixed number of consecutive captured images in the order of capturing.

[0015] In the particle group characteristic measuring device, preferably, the particle group characteristic measuring device also includes a calculation instruction unit, which outputs a calculation instruction signal to the particle group characteristic calculation unit, and the calculation instruction signal indicates the calculation of the particle group characteristic, and the calculation instruction unit outputs the calculation instruction signal at predetermined time intervals.

[0016] In this way, it is possible to grasp the changes in the characteristics of the particle swarm at regular intervals, thereby improving user convenience.

[0017] In the particle group characteristic measuring device, preferably, the particle group characteristic measuring device also includes a calculation instruction unit, which outputs a calculation instruction signal to the particle group characteristic calculation unit, and the calculation instruction signal indicates the calculation of the particle group characteristics. The calculation instruction unit outputs the calculation instruction signal whenever the particle information extraction unit extracts the particle information from a predetermined number of the captured images.

[0018] In this way, it is possible to grasp the change of the particle group at the time when the particle group is imaged, thereby improving user convenience.

[0019] In the particle group characteristic measurement device, preferably, the particle group characteristic measurement device further includes a display control unit configured to display the calculation results at the respective time points calculated by the particle group characteristic calculation unit in real time.

[0020] In this way, the user can confirm the temporal changes in the particle swarm characteristics in real time.

[0021] In the particle group characteristic measurement device, preferably, the particle group characteristic calculation unit calculates a plurality of different particle group characteristics, and the display control unit displays the plurality of particle group characteristics on the same screen.

[0022] In this way, by displaying different types of particle group characteristics as multiple particle group characteristics on the same screen, it is possible to grasp the temporal changes in the state of the particle group. 50 When the representative aspect ratio is used as a characteristic of multiple particle groups, if the representative particle size D 50 If the value of decreases with time and the aspect ratio increases with time, it can be understood that there is a possibility that the dispersed particles are being destroyed or deformed.

[0023] As a specific aspect of the characteristics of the particle group, representative particle diameters of the plurality of particles constituting the particle group can be cited.

[0024] In addition, the particle group characteristic measurement method of the present invention is a method for measuring the temporal changes in particle group characteristics, wherein the particle group characteristics are characteristics of a particle group composed of multiple particles dispersed in a dispersion medium, and the particle group characteristic measurement method includes: a shooting step of shooting the particle group; a particle information extraction step of processing the captured image captured in the shooting step to extract particle information, wherein the particle information is information about the particles reflected in the captured image; and a particle group characteristic calculation step of calculating the particle group characteristics at the multiple time points based on the particle information extracted from the multiple captured images captured before each time point along a time series. In the particle group characteristic calculation step, the particle group characteristics at each time point are calculated based on the particle information extracted from the multiple captured images whose shooting time period partially overlaps with the shooting time period of the multiple captured images used to calculate the particle group characteristics at a time point earlier than each time point.

[0025] Such a particle group characteristic measurement method can achieve the same effects as the particle group characteristic measurement device of the present invention described above.

[0026] In addition, the storage medium of the present invention stores a program for a particle group characteristic measuring device, which is a program for a particle group characteristic measuring device that measures the temporal changes in particle group characteristics, wherein the particle group characteristics are characteristics of a particle group composed of multiple particles dispersed in a dispersion medium, and the particle group characteristic measuring device program causes a computer to function as: a particle information extraction unit, which processes a captured image captured by a capturing unit that captures the particle group to extract particle information, wherein the particle information is information about the particles reflected in the captured image; and a particle group characteristic calculation unit, which calculates the particle group characteristics at multiple time points based on the particle information extracted from multiple captured images captured before each time point along a time series, and calculates the particle group characteristics at each time point based on the particle information extracted from multiple captured images whose time period partially overlaps with the time period of the multiple captured images used to calculate the particle group characteristics at a time point earlier than each time point.

[0027] Such a program for a particle group characteristics measurement device can achieve the same effects as those of the particle group characteristics measurement device of the present invention.

[0028] In addition, the particle size distribution measuring device of the present invention measures the particle size distribution of a particle group composed of multiple particles dispersed in a dispersion medium, and the particle size distribution measuring device includes: a circulation system that circulates the suspension between a mixing tank and a measuring cell, and the mixing tank mixes the dispersion medium and the particles to form the suspension; an optical measurement system that measures the particle size distribution of the particle group based on the scattered light generated by irradiating the suspension flowing through the measuring cell with a laser; and the above-mentioned particle group characteristic measuring device of the present invention, which measures the temporal changes in the characteristics of the particle group in the suspension flowing through the circulation system.

[0029] With such a particle size distribution measuring device, the particle size distribution characteristics of the suspension flowing through the circulation system are monitored using the particle size distribution characteristics device of the present invention. This makes it easier to understand the temporal changes in the particle size distribution characteristics within the circulation system. Therefore, particle size distribution measurement using an optical measurement system can be started at a more appropriate time than before.

[0030] In addition, the particle size distribution measurement method of the present invention is a method for measuring the particle size distribution of a particle group composed of multiple particles dispersed in a dispersion medium, and the particle size distribution measurement method includes: a circulation step, causing the suspension to circulate between a mixing tank and a measuring cell, and the mixing tank mixes the dispersion medium and the particles to form the suspension; a particle group characteristic measurement step, using the above-mentioned particle group characteristic measurement method of the present invention, to measure the time-dependent changes in the characteristics of the particle group in the circulating suspension; and a particle size distribution measurement step, based on the scattered light generated by irradiating the suspension flowing through the measuring cell with a laser.

[0031] According to such a particle size distribution measuring method, the same operation and effects as those of the particle size distribution measuring apparatus of the present invention can be achieved.

[0032] According to the present invention thus constructed, a particle group characteristic measuring device can be provided for measuring the temporal variation of the particle group characteristics based on the captured images of the particle group. The particle group characteristic measuring device can reduce the statistical errors contained in the calculated particle group characteristics and easily grasp the temporal variation of the particle group characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a diagram schematically showing the overall structure of the particle size distribution measuring apparatus according to this embodiment.

[0034] Figure 2 This is a diagram showing an example of an image captured by the imaging unit according to the same embodiment.

[0035] Figure 3 This is a functional block diagram of a particle swarm characteristic measuring device according to the same embodiment.

[0036] Figure 4 This is a diagram illustrating the flow of particle group characteristics calculation by the particle group characteristics measuring device according to the same embodiment.

[0037] Figure 5 This is a screen diagram illustrating a portion of a display screen of a display according to the same embodiment.

[0038] Figure 6 This is a screen diagram illustrating a portion of a display screen of a display according to the same embodiment.

[0039] Figure 7 This is a flowchart showing the particle information extraction operation of the particle size distribution measuring apparatus according to the same embodiment.

[0040] Figure 8 This is a flowchart showing the particle group characteristic calculation operation of the particle size distribution measuring apparatus according to the same embodiment.

[0041] Figure 9 This is a functional block diagram of a particle swarm characteristic measuring device according to another embodiment.

[0042] Description of Reference Numerals

[0043] 200 Particle Swarm Characteristics Measurement Device

[0044] 21 Image acquisition pool

[0045] 22 Light source for image acquisition

[0046] 23 Filming Department

[0047] 24 Second information processing device

[0048] 241 Particle Information Extraction Unit

[0049] 242 Storage Department

[0050] 243 Particle Swarm Characteristics Calculation Department

[0051] 245 Display Control Unit

[0052] 25 Display DETAILED DESCRIPTION

[0053] The following describes a particle group characteristics measurement device 200 according to one embodiment of the present invention with reference to the accompanying drawings. The particle group characteristics measurement device 200 of this embodiment constitutes a portion of the particle size distribution measurement device 100, which measures the particle size distribution of a particle group composed of a plurality of particles dispersed in a dispersion medium. The following first describes the overall structure of the particle size distribution measurement device 100, followed by a description of the structure of the particle group characteristics measurement device 200.

[0054] The particle size distribution measuring device 100 measures the particle size distribution of a particle group by detecting the intensity of scattered light generated when a laser is irradiated onto the particle group. Figure 1 As shown, the particle size distribution measuring device 100 includes: a circulation system 11, which connects the sample input tank 111 and the laser diffraction cell 112 through a circulation flow channel 113, so that the suspension obtained by dispersing the powder sample into the dispersion medium circulates; an optical (specifically diffraction / scattering) measuring system 12, which measures the particle size distribution of the particle group based on the scattered light generated by irradiating the laser to the suspension flowing through the laser diffraction cell 112; and a particle group characteristic measuring device 200, which measures the temporal change of the characteristics of the particle group (also called particle group characteristics) in the suspension flowing through the circulation system 11.

[0055] The sample feeding tank 111 mixes the fed powder sample containing multiple particles with a dispersion medium (e.g., pure water, ethanol, etc.) to form a suspension. By mixing the powder sample and the dispersion medium, the particles contained in the powder sample are dispersed in the dispersion medium to form a particle group.

[0056] The circulation system 11 is provided with a centrifugal circulation pump 114 for forcibly circulating the suspension, and sends the suspension mixed in the sample input tank 111 to the laser diffraction cell 112 .

[0057] The laser diffraction cell 112 is a so-called flow cell configured to allow a suspension introduced from the outside to flow fluid-tightly between a pair of opposing light-transmitting plates and then be discharged to the outside. Laser light is irradiated from one light-transmitting plate toward the other light-transmitting plate.

[0058] The optical measurement system 12 comprises: a laser light source 121 for irradiating a laser onto a suspension in a laser diffraction cell 112; a plurality of light detectors 122 for detecting the intensity of scattered light generated by the irradiation of the laser according to the scattering angle; and a first information processing device 123 for calculating the particle size distribution of the particle group based on the light intensity signals output by the plurality of light detectors 122.

[0059] The first information processing device 123 is physically a general-purpose or dedicated computer having a CPU, memory, input / output interfaces, etc., and makes the CPU and peripheral devices cooperate according to a predetermined program stored in a predetermined area of ​​the memory, thereby performing at least the function of a particle size distribution calculation unit 123a.

[0060] The particle size distribution calculation unit 123a calculates the particle size distribution of the particle group in the suspension based on the light intensity signals output from the plurality of light detectors 122. Specifically, the particle size distribution corresponding to the scattering pattern is calculated based on a scattering pattern consisting of scattering angles and the intensity of scattered light at those scattering angles, as indicated by the light intensity signals output from the plurality of light detectors 122, and a predetermined theoretical calculation formula derived from Mie scattering theory, Rayleigh scattering theory, Fraunhofer diffraction theory, and the like.

[0061] The particle group characteristic measurement device 200 measures temporal changes in particle group characteristics by processing images obtained by continuously capturing particles in a suspension. Specifically, the particle group characteristic measurement device 200 comprises: an image acquisition pool 21 connected to a circulation channel 113 through which the suspension circulates; an image acquisition light source 22 for irradiating the suspension within the image acquisition pool 21; an imaging unit 23 for capturing the suspension within the image acquisition pool 21; a second information processing device 24 for processing the images captured by the imaging unit 23 to calculate particle group characteristics; and a display 25 for displaying the calculation results of the second information processing device 24.

[0062] The image acquisition cell 21 is a so-called flow cell that allows a suspension introduced from the outside to flow between a pair of opposing light-transmitting plates and be discharged to the outside. Light is irradiated from one light-transmitting plate toward the other light-transmitting plate.

[0063] The image acquisition light source 22 irradiates parallel light toward the suspension in the image acquisition cell 21 and includes, for example, an LED device such as a white LED and a focusing mechanism such as a lens that focuses light emitted from the LED device into parallel light.

[0064] The imaging unit 23 continuously images the particle group in the suspension flowing through the image acquisition pool 21, and sequentially outputs images representing the captured images to the second information processing device 24 (see FIG. Figure 2 Specifically, the imaging unit 23 includes an imaging element such as a color or black-and-white CCD or CMOS image sensor.

[0065] The imaging unit 23 of this embodiment is configured to receive an imaging command signal instructing imaging from the second information processing device 24 and, using the imaging command signal as a trigger, to image the particle group in the suspension. Here, the imaging unit 23 is configured to capture and output an image of the particle group in the suspension each time it receives the imaging command signal.

[0066] The second information processing device 24 is physically a general-purpose or dedicated computer equipped with a CPU, a memory, an input / output interface, etc. The information processing device makes the CPU and peripheral devices cooperate according to a predetermined program stored in a predetermined area of ​​the memory, thereby Figure 3 As shown, it functions as at least a particle information extraction unit 241 , a storage unit 242 , a particle group characteristic calculation unit 243 , a calculation instruction unit 244 , and a display control unit 245 .

[0067] The particle information extraction unit 241 receives the captured image data output from the shooting unit 23, processes the captured image shown by the captured image data in sequence, and extracts the information of the particles reflected in the captured image, that is, the particle information. Specifically, the particle information extraction unit 241 performs image processing such as smoothing, noise removal, excision, circular separation, thinning, binarization, emphasis and / or edge detection on the captured image shown by the captured image data, and extracts the particle information of each particle reflected in the captured image (specifically, the so-called focused particles located within a predetermined depth of field). The "particle information" is the physical property value of each particle constituting the particle group, for example, the particle size (area equivalent diameter), aspect ratio (aspect ratio), major axis length, minor axis length, maximum distance, circumference, area (measured μm) 2 ), area (pixel: number of pixels within a particle), roundness, convexity, intensity of captured pixels, etc., but are not limited to these.

[0068] Upon receiving captured image data, the particle information extraction unit 241 immediately processes the captured image to extract information about each particle. Furthermore, the particle data representing the particle information of each particle extracted from the captured image is stored as a single particle data group in the storage unit 242, which is located in a predetermined area of ​​the memory. The particle information extraction unit 241 processes the captured image data each time it receives it, and stores the newly extracted particle data group separately from previously stored particle data groups in the storage unit 242.

[0069] For example Figure 4 As shown, when three particles are reflected in the n-th captured image received from the imaging unit 23, the particle information extraction unit 241 extracts the particle sizes of the three particles from the captured image as particle information. Furthermore, the particle data related to the three extracted particle sizes is stored in the storage unit 242 as the n-th particle data group.

[0070] Furthermore, the particle information extraction unit 241 is configured to immediately output an imaging command signal to the imaging unit 23 upon completion of particle information extraction from a received captured image. Furthermore, the particle information extraction unit 241 of this embodiment is configured to delete the captured image data representing the captured image upon completion of particle information extraction from the captured image, rather than storing the data in the storage unit 242. This reduces the amount of data stored in the storage unit 242.

[0071] The storage unit 242 is configured to store a predetermined upper limit of particle data groups. When the number of stored particle data groups reaches the upper limit, the storage unit 242 is configured to delete the oldest stored particle data group when a new particle data group is received.

[0072] The particle group characteristic calculation unit 243 calculates the particle group characteristics at the multiple time points based on the particle information extracted from the multiple captured images captured before each of the multiple time points along the time series. Specifically, the particle group characteristic calculation unit 243 is configured to refer to the particle data group stored in the storage unit 242, and calculate the particle group characteristics at each time point based on the particle information contained in the multiple particle data groups extracted before each time point. The "particle group characteristic" refers to the representative value of the particle information of each particle constituting the particle group. For example, in the case where the particle information is "particle size", the particle group characteristic is the "representative particle size (D 10 、D 50 、D 90 wait)".

[0073] However, the particle swarm characteristic calculation unit 243 of this embodiment calculates the particle swarm characteristics at each time point based on at least some of the particle information contained in the multiple particle data groups that overlap with the multiple particle data groups used to calculate the particle swarm characteristics at the previous time point. In other words, it can be said that the particle swarm characteristic calculation unit 243 is configured to calculate the particle swarm characteristics at the next time point by taking into account the particle information used to calculate the particle swarm characteristics at the previous time point.

[0074] The particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at each time point based on multiple particle data groups that include at least the most recently extracted particle data group at the time point immediately preceding each time point and a particle data group extracted more recently than the particle data group. More specifically, the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at each time point based on the particle information contained in the multiple particle data groups that include the most recently extracted particle data group at each time point. Furthermore, the particle swarm characteristics at each time point are calculated based on the particle information contained in a fixed number of consecutive particle data groups extracted in the order in which they were extracted. The number of particle data groups referenced at each time point can be arbitrarily set by the user.

[0075] For example, when the number of particle data groups referenced at each time point is set to "20", Figure 4 As shown, the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at a certain time point P based on the 20 consecutive particle data groups from the most recently extracted nth particle data group to the n-19th particle data group. Furthermore, the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at the next time point Q based on the 20 consecutive particle data groups from the most recently extracted n+6th particle data group to the n-13th particle data group.

[0076] Specifically, if Figure 4 As shown, when calculating the particle group characteristics at each time point, the particle group characteristics calculation unit 243 calculates a histogram (horizontal axis: particle size, vertical axis: frequency) based on multiple particle information contained in multiple particle data groups, and calculates the particle group characteristics based on the histogram. The particle group characteristics calculation unit 243 can also be configured to calculate different multiple particle group characteristics at each time point. The particle group characteristics calculation unit 243 can calculate, for example, a representative particle size D at each time point. 10 、D 50 and D 90 It can calculate characteristics of multiple particle groups of the same type, such as representative particle size, aspect ratio, and roundness, as well as characteristics of different types of particle groups.

[0077] Once the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at each time point, it immediately outputs the particle swarm characteristic data representing the particle swarm characteristics at each time point. Furthermore, it may output histogram data representing a histogram used to calculate the particle swarm characteristics along with the particle swarm characteristic data.

[0078] The calculation instruction unit 244 outputs a calculation instruction signal to the particle swarm calculation unit 243 to instruct the calculation of the particle swarm characteristics. The calculation instruction unit 244 of this embodiment is configured to measure time based on a signal from a clock built into the second information processing device 24 and output a calculation instruction signal at a predetermined time. The timing at which the calculation instruction unit 244 outputs the calculation instruction signal can be a fixed time interval (e.g., 1 second interval) or a predetermined time. Moreover, if the particle swarm characteristic calculation unit 243 receives the calculation instruction signal, it reads the particle data from the storage unit 242 and calculates the particle swarm characteristics.

[0079] The display control unit 245 receives the particle group characteristic data and displays it on the display 25 as a calculation result. Specifically, the display control unit 245 causes the display 25 to display a coordinate graph with the horizontal axis set to time and the vertical axis set to the value of the particle group characteristic, and the particle group characteristics at each time point calculated by the particle group characteristic calculation unit 243 are sequentially depicted on the coordinate graph. Here, the position of the horizontal axis of each coordinate graph represents the time when the particle group characteristics are calculated, which is based on the time of the clock built into the second information processing device 24. Specifically, this time is the time when the clock outputs the calculation instruction signal. In addition, in the case where the particle group characteristics calculated by the particle group characteristic calculation unit 243 have multiple types, the display control unit 245 can also depict the multiple particle group characteristics on the same coordinate graph. In addition, in the case where the value shown in the particle group characteristics at the latest time point being displayed is within a predetermined range (for example, within the range representing the particle size D 50 Exceeds the predetermined threshold D th), the display control unit 245 causes the display 25 to display a message indicating that the particle size distribution measurement can be started.

[0080] In addition, the display unit control unit may receive the histogram data and display it on the display 25 as a calculation result.

[0081] Figure 5 and Figure 6 An example of a screen displayed on the display 25 is shown. Figure 5 As shown, the display 25 shows the characteristics of the particle group (here, D as a representative particle size). 10 、D 50 and D 90 ) is a particle swarm characteristic change coordinate diagram that changes with time. In this particle swarm characteristic change coordinate diagram, the latest value is plotted at fixed time intervals (here, every 1 second). Figure 5 As shown, if the predetermined particle group characteristics (here D 50 ) is lower than the set threshold D th , a message urging the user to perform laser diffraction is displayed. Figure 6 As shown, a histogram (with the horizontal axis representing particle size and the vertical axis representing frequency of particle size distribution) calculated based on the particle information extracted from the most recent consecutive multiple captured images at each time point is displayed in real time on the display 25. The histogram is updated to the latest state at regular intervals (here, every second). Figure 5 and Figure 6 The pictures shown may be displayed on different pictures or on the same picture.

[0082] Next, refer to Figure 7 The operation of the particle swarm characteristic measuring device 200 having the above configuration will be described with reference to the flowchart of FIG.

[0083] (Particle information extraction action)

[0084] The operation of extracting particle information from the suspension will be described. In the particle size distribution measuring apparatus 100 , a powder sample is placed in the sample placement tank 111 and mixed with a dispersion medium. After the resulting suspension begins to circulate through the circulation system 11 , the operation of extracting particle information from the suspension begins.

[0085] First, light is irradiated from the image acquisition light source 22 onto the suspension flowing through the image acquisition pool 21. Then, the imaging unit 23 captures the particle group in the suspension flowing through the image acquisition pool 21 (step S11), and immediately outputs the captured data to the second information processing device 24. The particle information extraction unit 241 processes the output captured image and extracts information (particle information) of each particle reflected in the captured image (step S12). If the extraction of particle information from the captured image is completed (step S13), the extracted one or more particle information is stored as a particle data group in the storage unit 242 (step S14). The actions of steps S11 to S14 are repeated until a predetermined time has passed since the start of the action (step S15).

[0086] (Particle swarm characteristic calculation action)

[0087] This section describes the process of calculating the particle swarm characteristics of a particle swarm based on the particle information extracted by the particle information extraction process. This process begins after the particle information extraction process begins and is executed in parallel with the particle information extraction process. In the particle swarm characteristics calculation process, the particle swarm characteristics are calculated at predetermined, fixed time intervals.

[0088] At a predetermined time, the storage unit 242 is referred to, and a predetermined plurality of particle data groups that have been recently extracted and are continuous in sequence are obtained (step S21), and a histogram is calculated based on the particle information contained in the plurality of particle data groups (step S22). Based on the calculated histogram, the particle group characteristics are calculated (step S23). The value of the calculated particle group characteristics is plotted on a coordinate graph on the display 25 (step S24). When the value of the calculated particle group characteristics is within a predetermined range (for example, above a predetermined threshold) (step S27), a message indicating that laser diffraction can be performed in the particle size distribution measuring device 100 is displayed on the display 25 (step S26). When the predetermined time has not passed since the start of the action (step S27), a predetermined plurality of particle data groups that have been recently extracted and are continuous in sequence are obtained at the next predetermined time (step S21). Here, the particle group characteristics calculation unit 243 obtains the particle data group in such a way that a portion of the particle data group overlaps with the particle data group obtained at the previous time. Then, the operations of step S21 to step S26 are repeated until a predetermined time has passed since the start of the operation (step S27).

[0089] According to the particle swarm characteristic measuring device 200 of this embodiment constructed in this manner, the particle swarm characteristics at each time point are calculated based on the particle information extracted from a plurality of consecutive captured images including the most recent captured image. Therefore, compared with the case where the particle information is calculated based on the particle information extracted from a single captured image, the statistical amount of the particle information can be increased, and the statistical error contained in the calculated particle swarm characteristics can be reduced. Moreover, the captured images obtained up to a time point earlier than each time point are used as part of the plurality of captured images used to calculate the particle swarm characteristics at each time point. Therefore, the time required to ensure the number of particle information required to reduce the statistical error to within the allowable range can be shortened, and the particle swarm characteristics at each time point can be calculated in a short time. Thus, the statistical error contained in the calculated particle swarm characteristics can be reduced, and the temporal variation of the particle swarm characteristics can be easily grasped.

[0090] Moreover, the particle size distribution measuring device 100 of this embodiment uses such a particle group characteristic measuring device 200 to monitor the temporal changes in the characteristics of the particle group in the suspension flowing through the circulation system 11, so that, for example, the particle size distribution measurement using the optical measuring system 12 can be started at an appropriate time while observing the dispersion state of the particles.

[0091] <Other Modified Embodiments>

[0092] In addition, the present invention is not limited to the above-described embodiment.

[0093] In the above embodiment, the calculation instruction unit 244 is configured to measure time based on a signal from a clock and output a calculation instruction signal at a predetermined timing, but the present invention is not limited thereto. Figure 9 As shown, the calculation instruction unit 244 of other embodiments can also be configured to count the number of captured images processed by the particle information extraction unit 241, and to output a calculation instruction signal to the particle group characteristic calculation unit 243 each time the particle information extraction unit 241 extracts particle information from a predetermined number of captured images.

[0094] In this case, it is preferable that the particle information extraction unit 241 processes the captured image and extracts the capturing time of the captured image, and stores the capturing time of the captured image in association with the particle data group extracted from the captured image in the storage unit 242. Furthermore, upon receiving the calculation instruction signal, the particle group characteristic calculation unit 243 calculates the particle group characteristics by referring to a predetermined number of particle data groups, and determines a single time associated with the calculated particle group characteristics by referring to a plurality of capturing times associated with the predetermined number of particle groups, and outputs the single time as capturing time data to the display control unit 245. Here, the time indicated by the capturing time data may be any one of the plurality of referenced capturing times, or may be a time representing the elapsed time from a predetermined reference time calculated based on the plurality of referenced capturing times.

[0095] In the aforementioned embodiment, the particle information extraction unit 241 calculates the particle swarm characteristics at each time point based on particle information contained in multiple particle data groups that partially overlap with multiple particle data groups used to calculate the particle swarm characteristics at the previous time point, but the present invention is not limited thereto. The particle information extraction unit 241 may calculate the particle swarm characteristics at each time point based on particle information extracted from multiple captured images whose time periods partially overlap with the time periods of multiple captured images used to calculate the particle swarm characteristics at a time point prior to each time point.

[0096] The image acquisition cell 21 in the above embodiment is a flow cell, but is not limited thereto and may also be a batch cell. When a batch cell 21 is used, temporal changes in particle group characteristics caused by temperature changes in the dispersion medium can be detected.

[0097] In the aforementioned embodiment, the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at each time point based on the particle information contained in the most recently extracted particle data group, but the present invention is not limited thereto. In other embodiments, the particle swarm characteristics may be calculated based on the particle information contained in multiple particle data groups excluding the most recently extracted particle data group.

[0098] In the above embodiment, the particle swarm characteristic calculation unit 243 calculates the particle swarm characteristics at each time point based on the particle information contained in multiple particle data groups whose extraction order is continuous, but the present invention is not limited to this. In other embodiments, the particle swarm characteristics may also be calculated based on the particle information contained in multiple particle data groups whose extraction order is discontinuous.

[0099] The particle group characteristic measuring device 200 of the above embodiment constitutes a part of the particle size distribution measuring device 100, but is not limited thereto. Of course, the particle group characteristic measuring device 200 may be used alone.

[0100] In the above embodiment, the functions of the particle size distribution calculation unit 123a, the particle information extraction unit 241, the storage unit 242, the particle group characteristics calculation unit 243, and the display control unit 245 are performed by different computers, but the present invention is not limited to this. In other embodiments, these functions may be performed by a common computer.

[0101] In the above embodiment, a single computer performs the functions of the particle information extraction unit 241 , the storage unit 242 , the particle group characteristic calculation unit 243 , and the display control unit 245 , but the present invention is not limited thereto. In other embodiments, these functions may be performed by a plurality of computers.

[0102] In the aforementioned embodiment, the particle information extraction and particle swarm characteristic calculation operations are terminated upon the elapse of a predetermined time from the start of the operations, but this is not limiting. In other embodiments, the particle information extraction operation may be terminated upon the extraction of particle information from a predetermined number of captured images. The particle swarm characteristic calculation operation may be terminated when the calculated particle swarm characteristic value exceeds or falls below a predetermined value, or when the particle swarm characteristic value has been calculated a predetermined number of times. Furthermore, both the particle information extraction and particle swarm characteristic calculation operations may be terminated upon the user pressing an end button.

[0103] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

[0104] Industrial Applicability

[0105] According to the present invention, a particle swarm characteristic measuring device can be provided for measuring the temporal variation of particle swarm characteristics based on captured images of a particle swarm. The particle swarm characteristic measuring device can reduce the statistical errors contained in the calculated particle swarm characteristics and easily grasp the temporal variation of the particle swarm characteristics.

Claims

1. A particle group characteristic measuring device for measuring temporal changes in particle group characteristics, wherein the particle group characteristics are characteristics of a particle group composed of a plurality of particles dispersed in a dispersion medium. The particle group characteristic measuring device is characterized by comprising: an imaging unit including an imaging element and continuously capturing images of the particle group, wherein each of the continuously captured images of the particle group is captured using the imaging element; a particle information extraction unit that processes the image captured by the imaging unit to extract particle information, wherein the particle information is information about particles reflected in the image; as well as a particle group characteristic calculation unit that calculates the particle group characteristics at a plurality of time points based on the particle information extracted from a plurality of images captured before each of the plurality of time points along a time series, A time period for capturing a portion of the captured images for calculating the particle group characteristics at one of the multiple time points overlaps a time period for capturing a portion of the captured images for calculating the particle group characteristics at a time point before the one time point.

2. The particle group characteristic measuring device according to claim 1, characterized in that A portion of the plurality of captured images used by the particle group characteristic calculation unit to calculate the particle group characteristic at one of the plurality of time points overlaps with a portion of the plurality of captured images used by the particle group characteristic calculation unit to calculate the particle group characteristic at a time point before the one time point.

3. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic calculation unit calculates the particle group characteristic at each time point based on the plurality of particle information including the particle information most recently extracted from the captured image at each time point.

4. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic calculation unit calculates the particle group characteristic at each time point based on the particle information extracted from a fixed number of the captured images that are continuous in the order of capture.

5. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic measuring device further includes a calculation instruction unit, which outputs a calculation instruction signal to the particle group characteristic calculating unit, wherein the calculation instruction signal instructs calculation of the particle group characteristic. The calculation instruction unit outputs the calculation instruction signal at predetermined time intervals.

6. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic measuring device further includes a calculation instruction unit, which outputs a calculation instruction signal to the particle group characteristic calculating unit, wherein the calculation instruction signal instructs calculation of the particle group characteristic. The calculation instruction unit outputs the calculation instruction signal every time the particle information extraction unit extracts the particle information from a predetermined number of the captured images.

7. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic measurement device further includes a display control unit configured to display the calculation results at the respective time points calculated by the particle group characteristic calculation unit in real time.

8. The particle group characteristic measuring device according to claim 7, characterized in that: The particle group characteristic calculation unit calculates a plurality of different particle group characteristics. The display control unit displays the plurality of particle group characteristics on the same screen.

9. The particle group characteristic measuring device according to claim 1 or 2, characterized in that: The particle group characteristic is a representative particle size of a plurality of particles constituting the particle group.

10. A method for measuring a particle group characteristic, the method being a method for measuring temporal changes in a particle group characteristic, wherein the particle group characteristic is a characteristic of a particle group composed of a plurality of particles dispersed in a dispersion medium. The particle group characteristic determination method is characterized by comprising: a photographing step of continuously photographing images of the particle group by an imaging unit including an imaging element, wherein each of the continuously photographed images of the particle group is photographed using the imaging element; a particle information extraction step of processing the image captured in the capturing step to extract particle information, wherein the particle information is information about particles reflected in the image; as well as a particle group characteristic calculation step of calculating the particle group characteristics at the plurality of time points based on the particle information extracted from the plurality of captured images captured before each of the plurality of time points along a time series, A time period for capturing a portion of the captured images for calculating the particle group characteristics at one of the multiple time points overlaps a time period for capturing a portion of the captured images for calculating the particle group characteristics at a time point before the one time point.

11. A storage medium, characterized in that: A program for a particle group characteristic measuring device is stored, wherein the program for the particle group characteristic measuring device is a program for a particle group characteristic measuring device for measuring temporal changes in particle group characteristics, wherein the particle group characteristics are characteristics of a particle group composed of a plurality of particles dispersed in a dispersion medium. The particle group characteristic measuring device is programmed to cause a computer to: a function as an imaging unit including an imaging element and continuously imaging images of the particle group, wherein each of the continuously captured images of the particle group is captured using the imaging element; The particle information extraction unit processes an image captured by an imaging unit that captures the particle group to extract particle information, the particle information being information about particles reflected in the captured image. as well as As a function of a particle group characteristic calculation unit, the particle group characteristic calculation unit calculates the particle group characteristics at the plurality of time points based on the particle information extracted from the plurality of captured images captured before each of the plurality of time points along a time series, A time period for capturing a portion of the captured images for calculating the particle group characteristics at one of the multiple time points overlaps a time period for capturing a portion of the captured images for calculating the particle group characteristics at a time point before the one time point.

12. A particle size distribution measuring apparatus for measuring the particle size distribution of a particle group consisting of a plurality of particles dispersed in a dispersion medium. The particle size distribution measuring device is characterized by comprising: a circulation system for circulating the suspension between a mixing tank and a measuring cell, wherein the mixing tank mixes the dispersion medium with the particles to form the suspension; an optical measurement system for measuring the particle size distribution of the particle group based on scattered light generated by irradiating the suspension flowing through the measurement cell with laser light; and The particle group characteristic measuring device according to claim 1 measures temporal changes in the characteristics of the particle group in the suspension flowing through the circulation system.

13. A particle size distribution measurement method, comprising measuring the particle size distribution of a particle group consisting of a plurality of particles dispersed in a dispersion medium. The particle size distribution measuring method is characterized by comprising: a circulation step of circulating the suspension between a mixing tank and a measuring cell, wherein the mixing tank mixes the dispersion medium with the particles to form the suspension; a particle group characteristic measuring step of measuring temporal changes in characteristics of the particle group in the circulating suspension using the method according to claim 10; and The particle size distribution measuring step measures the particle size distribution of the particle group based on scattered light generated by irradiating the suspension flowing through the measuring cell with laser light.

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