Mixing ratio determination method and mixing ratio determination device

Abstract

To provide a mixing ratio determination method and a mixing ratio determination device that can determine the mixing ratio of specific types of powder and particles in a material in which different types of powder and particles in the same color are mixed.SOLUTION: A mixed material obtained by mixing a plurality of types of powder and particles different in appearance from each other is photographed by a photographing instrument 53 to acquire a photographed image of the mixed material (S21), and the photographed image being a color image is converted into a gray scale image (S22). Subsequently, the luminance values of pixels of the gray scale image are acquired, and a dispersion value of the luminance values is calculated according to a definition formula of dispersion (S24). Then, processing of determining the mixing ratio of pulverized materials from the dispersion value of the luminance values, is performed (S25).SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a mixing ratio determination method and a mixing ratio determination device.

Background Art

[0002] In a molding machine for manufacturing resin molded products, a material obtained by mixing granular materials such as pellet-shaped virgin materials, crushed materials for reuse, and pigments at a predetermined ratio is charged. As for the charging method of the mixed material, for example, there are a method of charging into the molding machine a mixture of multiple types of granular materials previously mixed, and a method of charging into the molding machine while mixing multiple types of granular materials.

[0003] In any method, due to segregation, separation of granular materials, and variations in blending accuracy, it is not certain whether the granular materials are mixed at a predetermined ratio in the mixed material immediately before being charged into the molding machine. The mixing ratio of the granular materials in the mixed material is related to the quality of the resin molded product. If it can be determined that the mixing ratio is at a predetermined ratio, it becomes possible to adjust or stop before producing a large number of defective products in case of abnormality, contributing to the production yield of the resin molded product.

[0004] Therefore, a method has been proposed in which a mixed material composed of multiple types of granular materials with different colors is photographed to obtain a plurality of photographed images, and the ratio of the total value of the number of pixels having the color of one type of granular material to the total value of the number of pixels included in the entire plurality of photographed images is calculated as the measured area ratio, and the mixing ratio of the granular materials is determined based on the measured area ratio (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, with that method, it is impossible to distinguish different types of powder particles of the same color (multiple types of powder particles). A material obtained by mixing virgin material and recycled material as pulverized material may be used for resin molding, and it is difficult to determine the mixing ratio of the powder particles in such a mixed material.

[0007] An object of the present invention is to provide a mixing ratio determination method and a mixing ratio determination device capable of determining the mixing ratio of a specific type of powder particles in a material in which different types of powder particles of the same color are mixed.

Means for Solving the Problems

[0008] To achieve the above object, a mixing ratio determination method according to one aspect of the present invention includes a photographing step of photographing a mixed material in which a plurality of types of powder particles having different appearances are mixed with a photographing device to obtain an image of the mixed material, a region dividing step of dividing the image obtained in the photographing step into regions in units of powder particles, an identifying step of identifying each image region divided in the region dividing step from the shape of its contour, and a determining step of determining the mixing ratio of a specific type of powder particles from the identification result in the identifying step.

[0009] According to this method, even if the mixed material contains powder particles of the same color but different shapes, it is possible to determine the mixing ratio of a specific type of powder particles.

[0010] The method includes an observation unit having an observation window for observing the inside, a mixed material in which a plurality of types of powder particles having different appearances are mixed is supplied to the inside, a photographing device for photographing the mixed material supplied to the observation unit through the observation window, and an analysis processing unit for analyzing the image photographed by the photographing device. The analysis processing unit can be implemented by a mixing ratio determination device that executes a region dividing process for dividing the image into regions in units of powder particles, an identification process for identifying each image region divided in the region dividing process from the shape of its contour, and a determination process for determining the mixing ratio of a specific type of powder particles from the identification result by the identification process.

[0011] Before the region division step, a binarization step of binarizing the image acquired in the imaging step may be further included.

[0012] Also, the image acquired in the imaging step is a color image, and before the binarization step, a grayscale step of converting the color image acquired in the imaging step into a grayscale image, an averaging step of averaging the grayscale image after the grayscale step, and a step of removing unevenness in the background from the color image acquired in the imaging step using the grayscale image after the averaging step may be further included.

[0013] Before the region division step, an inversion step of inverting the black and white of regions with an area equal to or less than a certain area in the image binarized in the binarization step may be further included.

[0014] After the inversion step and before the identification step, a padding step of performing padding on each image region divided in the region division step may be further included.

[0015] In the imaging step, illumination light may be irradiated from the imaging device side onto the mixed material. In this configuration, the illumination light (reflected light) reflected by the mixed material enters the imaging device, and an image of the reflected light entering the imaging device is acquired as a captured image of the mixed material.

[0016] A method for determining the mixing ratio according to another aspect of the present invention includes an imaging step of imaging a mixed material in which a plurality of types of powder particles having different appearances are mixed with an imaging device to obtain a color image of the mixed material, a grayscale step of converting the color image obtained in the imaging step into a grayscale image, an evaluation value calculation step of obtaining the luminance of each pixel of the grayscale image after the grayscale step and calculating a dispersion value or an integrated value of the obtained luminance, and a determination step of determining the mixing ratio of a specific type of powder particle from the dispersion value or the integrated value calculated in the evaluation value calculation step.

[0017] According to this method, when the mixed material contains powder particles of the same color but different types, the mixing ratio of a specific type of powder particle can be determined regardless of the shape of those powder particles.

[0018] The method includes an observation unit having an observation window for observing the interior, into which a mixed material in which a plurality of types of powder particles having different appearances are mixed is supplied; an imaging device that images the mixed material supplied to the observation unit through the observation window; and an analysis processing unit that analyzes the color image captured by the imaging device. The analysis processing unit performs grayscale processing for converting the color image into a grayscale image, after the grayscale processing, obtains the luminance of each pixel of the grayscale image, and performs evaluation value calculation processing for calculating the variance value or integrated value of the obtained luminance, and performs determination processing for determining the mixing ratio of a specific type of powder particle from the variance value or integrated value calculated in the evaluation value calculation processing. It can be implemented by a mixing ratio determination device.

[0019] In the imaging step, illumination light may be irradiated from the side opposite to the imaging device side onto the mixed material. In this configuration, the illumination light (transmitted light) transmitted through the mixed material enters the imaging device, and an image of the transmitted light incident on the imaging device is obtained as a captured image of the mixed material.

[0020] The method further includes a charging step of charging the mixed material into a predetermined device. In the imaging step, the mixed material charged into the predetermined device in the charging step may be imaged by the imaging device. Thereby, it is possible to determine the mixing ratio of a specific type of powder particle in the mixed material to be charged immediately before the mixed material is charged into the predetermined device.

Advantages of the Invention

[0021] According to the present invention, it is possible to determine the mixing ratio of a specific type of powder particle in a material in which powder particles of the same color but different types, such as powder particles of the same color but different shapes, are mixed.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0024] <Resin Molding Product Manufacturing Equipment> FIG. 1 is a diagram schematically showing the configuration of a manufacturing facility 2 incorporating a mixing ratio determination device 1 according to an embodiment of the present invention.

[0025] The mixing ratio determination device 1 is a device incorporated in a manufacturing facility 2 for manufacturing resin molding products, and determines the mixing ratio of a specific type of powder or granule in the mixed material used in the manufacturing. The mixed material is a material obtained by mixing a plurality of types of powder or granule such as virgin material, crushed material, and pigment at a predetermined ratio. In addition to the mixing ratio determination device 1, the system 2 includes a weighing and mixing device 3 for weighing and mixing various powder or granule, a transport device 4 for transporting the mixed material from the weighing and mixing device 3, and a molding machine 5 such as an injection molding machine into which the mixed material transported by the transport device 4 is charged.

[0026] The weighing and mixing device 3 includes a raw material supply unit 11, a weighing unit 12, and a mixing unit 13.

[0027] The raw material supply unit 11 is provided with a plurality of raw material hoppers 21 for storing different types of powder or granule. Powder or granule as raw material is supplied to each raw material hopper 21 by pneumatic transportation from a raw material tank (not shown). In addition, each raw material hopper 21 is provided with a screw feeder 22. The powder or granule stored in the raw material hopper 21 is discharged from the raw material hopper 21 by the operation of the screw feeder 22.

[0028] The weighing unit 12 is provided with a weighing hopper 23, and the powder or granule discharged from each raw material hopper 21 is received by the weighing hopper 23. The lower part of the weighing hopper 23 is formed in a tapered shape, and the weighing hopper 23 is provided with a gate shutter 24 for opening and closing the discharge port at its lower end. In addition, the weighing hopper 23 is provided with a load cell 25 for measuring the mass of the powder or granule stored in the weighing hopper 23.

[0029] With the gate shutter 24 closed, when the operation of the screw feeder 22 of the raw material hopper 21 for storing the granular material to be measured is started, the granular material discharged from the raw material hopper 21 is stored in the weighing hopper 23. While the granular material stored in the weighing hopper 23 is being weighed by the load cell 25, the operation of the screw feeder 22 of the raw material hopper 21 is continued. When the specified quantity is weighed by the load cell 25, the operation of the screw feeder 22 is stopped. By sequentially controlling the operations of the screw feeders 22 of the respective raw material hoppers 21, a plurality of types of granular materials blended at a predetermined ratio are stored in the weighing hopper 23. When the gate shutter 24 is opened in this state, the plurality of types of granular materials stored in the weighing hopper 23 are discharged from the discharge port.

[0030] The mixing section 13 is disposed below the weighing section 12. The mixing section 13 includes a mixing container 31, a stirring blade 33 provided in the mixing container 31 and driven by a motor 32, and a shutter valve 34 that opens and closes a discharge port formed on the bottom surface of the mixing container 31.

[0031] With the shutter valve 34 closed, the granular material discharged from the discharge port of the weighing hopper 23 of the weighing section 12 is received by the mixing container 31, and the granular material is stored in the mixing container 31. When the motor 32 is driven and the stirring blade 33 rotates, the plurality of types of granular materials in the mixing container 31 are mixed together. When the granular materials in the mixing container 31 are sufficiently mixed, the shutter valve 34 is opened. When the shutter valve 34 is opened, the mixed material composed of the plurality of types of mixed granular materials is discharged from the discharge port of the mixing container 31.

[0032] The transport device 4 includes a supply hopper 41 disposed below the mixing container 31. The mixed material discharged from the discharge port of the mixing container 31 is received by the supply hopper 41. The lower part of the supply hopper 41 is formed in a tapered shape, and one end of a transport pipe 42 is connected to the discharge port at the lower end thereof via a gate 43. The other end of the transport pipe 42 is connected to a loader hopper 44 disposed above the molding machine 5.

[0033] When the air in the loader hopper 44 is sucked out with the gate 43 open, the mixed material stored in the supply hopper 41 is pneumatically transported through the transport pipe 42 to the loader hopper 44. The mixed material transported to the loader hopper 44 is put into the molding machine 5 from the loader hopper 44.

[0034] <Mixing ratio determination device> The mixing ratio determination device 1 includes an observation unit 51 having an observation window 58, a light source 52, photographing equipment 53, and an analysis processing unit 54.

[0035] The observation unit 51 is interposed between the loader hopper 44 and the molding machine 5 and has a space 55 inside through which the mixed material put into the molding machine 5 from the loader hopper 44 passes. The observation unit 51 includes a front plate 56 and a back plate 57 that face each other in parallel with each other across the space 55. The front plate 56 and the back plate 57 have, for example, the same configuration and are made of a light-transmitting plate-like body (resin plate, glass plate). The front plate 56 and the back plate 57 are joined to each other at their peripheral portions, and an inlet for introducing the mixed material and an outlet are formed between their upper end portions and lower end portions, respectively. Further, a light-blocking member is not arranged at the central portion surrounded by the peripheral portions of the front plate 56 and the back plate 57, and the central portion of the front plate 56 functions as an observation window 58 that allows the mixed material passing through the observation unit 51 to be observed from the outside.

[0036] The light source 52 has a substantially rectangular plate shape and is arranged to face the front plate 56 from the side opposite to the back plate 57. The central portion of the light source 52 is formed as a rectangular opening or is configured to block the opening with a colorless and transparent light guide plate. A plurality of LEDs (Light Emitting Diodes) arranged in a line and a reflecting plate that reflects the light of each LED toward the front plate 56 are arranged at the peripheral portion of the light source 52, and the light source 52 is configured to be able to illuminate at least the entire area within the observation window 58 of the front plate 56 with the light (illumination light) emitted toward the front plate 56.

[0037] The imaging device 53 is a camera equipped with a lens and an imaging element, and is capable of continuously capturing color still images at a predetermined frame rate. The imaging device 53 is arranged at a position distant from the light source 52 on the side opposite to the observation unit 51 side, such that its optical axis is orthogonal to the observation window 58 and is capable of capturing the mixed material passing through the inside of the observation unit 51 through the central portion of the light source 52 and the observation window 58. Note that other optical components such as zoom lenses and polarizing plates may be used in combination.

[0038] The analysis processing unit 54 is a device that analyzes the images captured by the imaging device 53, and consists of a computer that operates according to a program for the analysis. The computer incorporates a CPU and a memory. The memory includes a non-volatile memory such as a flash memory and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0039] Figure 2 is a block diagram showing the functional configuration of the mixing ratio determination device 1.

[0040] The mixing ratio determination device 1, for example, illuminates the mixed material passing through the inside of the observation window 58 with the illumination light from the light source 52 during a predetermined period within the period in which the mixed material transported from the metering and mixing device 3 by the transport device 4 is input into the molding machine 5. In parallel with this, the imaging device 53 captures the mixed material passing through the inside of the observation window 58 at a constant frame rate. The illumination light (reflected light) reflected by the mixed material is incident on the imaging device 53, and the analysis processing unit 54 acquires the image of the reflected light incident on the imaging device 53 as a captured image (still image) of the mixed material. This process is an example of the imaging process. Then, the analysis processing unit 54 stores the captured images of the mixed material acquired at a constant frame rate in the memory (volatile memory) (S1: Image storage).

[0041] The analysis processing unit 54 performs each of the processes described below on each of the captured images stored in the memory.

[0042] As a first process, a process of removing unevenness in the background due to uneven illumination or the like is performed (S2: background unevenness removal). In this process of removing background unevenness, first, a captured image, which is a color image, is converted into a grayscale image. The method of this conversion is well-known and will not be described here. Next, an averaging process (average filter process) for averaging the grayscale image is performed. In the averaging process, an average filter is used. For example, each pixel of the grayscale image is regarded as a target pixel, and the average value of the luminance values of the pixels included in a predetermined area centered on the target image is calculated. Then, the luminance value of the target pixel is replaced with the average value. By this averaging process, the difference in luminance values between pixels due to noise can be reduced. Then, the luminance value of the grayscale image after the averaging process is subtracted from the luminance value of the captured image, and the average luminance value of each pixel of the captured image is added to the subtracted value, whereby an image with background unevenness removed is obtained.

[0043] As a second process, a process of removing Gaussian noise resulting from a process of interpolating insufficient light quantity of illumination by the illumination light of the light source 52 or the like is performed (S3: noise removal). In this process of removing Gaussian noise, for example, a median filter, a Gaussian filter, an average filter, or the like is used. Since these filters are well-known, the description thereof will be omitted here.

[0044] As a third process, a binarization process of converting the captured image from which Gaussian noise has been removed into a binary image is performed (S4: binarization). Here, for example, a simple binarization method is adopted. For each pixel of the captured image, if the luminance value is equal to or greater than a certain threshold value, the pixel is converted into a white pixel (for example, white data "255"), and if the luminance value is less than a certain threshold value, the pixel is converted into a black pixel (black data "0").

[0045] As a fourth process, a hole filling process is performed to repair the "chips" of the powder particles included in the captured image (black-and-white image) after the binarization process (S5: hole filling). The step in which this hole filling process is performed is a determination step. In this hole filling process, first, a labeling process is performed. The labeling process is, for example, a process of assigning the same number to white pixels that are continuous in four directions vertically and horizontally or eight directions vertically, horizontally, and diagonally. Next, the area of the portion to which the same number is assigned is calculated, and for portions with an area equal to or less than a certain area, the white pixels included in that portion are inverted to black pixels. FIG. 3A shows an example of the black-and-white image after the hole filling process.

[0046] As a fifth process, a process of region-dividing the black-and-white image after the hole filling process into powder particle (work) units is performed (S6: region division of work). The step in which this region division process is performed is an example of a region division step. In this process, for example, the Watershed transformation algorithm is used. First, a shrinking process (Erosion) is performed to shrink the region (region to be divided) in which white pixels are aggregated in the black-and-white image. Next, in order to determine the region near the center of each region to be divided after the shrinking process, a distance transformation process is performed. In the distance transformation process, for each pixel in the region to be divided, the luminance value is converted so that pixels far from the background (region of black pixels) become white and images close to the background become black, and then binarization is performed so that only the region near the center remains. After that, a region that is neither a region near the center (foreground) nor the background is extracted from the entire image region. Also, a labeling process is performed on the region near the center. Then, for each region to be divided, each pixel from the center to the region that is neither foreground nor background is set as a white pixel. As a result, as shown in FIG. 3B, a black-and-white image region-divided into powder particle units is obtained.

[0047] As the sixth process, a process of identifying the workpiece is performed (S7: workpiece identification). The step in which this process is performed is an example of an identification step. In this process, in the black-and-white image after the region division process, first, by the labeling process, numbers are assigned to the regions (workpieces) where white pixels are aggregated, and each workpiece is individually identified. Next, for each workpiece, the coordinates of each vertex of the rectangle circumscribing the workpiece are acquired, and the image of the rectangular region is cut out. Then, zero-padding processing is performed on the cut-out image, where the luminance values of the pixels around the workpiece are set to "0". The step in which this zero-padding processing is performed is an example of a padding step. Also, when there are regions where multiple white pixels are aggregated within the rectangular region, the luminance values of the pixels other than the region with the largest area among them are set to "0".

[0048] As the seventh process, the concavity and convexity of the contour of each identified workpiece are calculated (S8: concavity and convexity calculation). The concavity and convexity are obtained, for example, by measuring the actual perimeter of the workpiece and the circumscribing perimeter of the workpiece (the line connecting the convex endpoints of the particles with straight lines), and dividing the measured perimeter by the circumscribing perimeter.

[0049] As the eighth process, a process of determining the type of the workpiece (powder particles) is performed (S9: workpiece type determination). The step in which this workpiece type determination process is performed is an example of a determination step. In this process, workpieces with a concavity and convexity less than a predetermined value and workpieces with a concavity and convexity greater than or equal to the predetermined value are separated. Then, as shown in Fig. 3C, workpieces with a concavity and convexity less than the predetermined value are determined to be virgin materials, and as shown in Fig. 3D, workpieces with a concavity and convexity greater than or equal to the predetermined value are determined to be crushed materials.

[0050] As the ninth process, a process of determining the mixing ratio of the pulverized material is performed (S10: Mixing ratio determination). In this process, in order to calculate the mixing ratio of the pulverized material, the ratio of the total number of pixels of the work representing the virgin material (white pixels) to the total number of pixels of the rectangular area cut out with the virgin material as the work and the rectangular area cut out with the pulverized material as the work is calculated as the virgin material area ratio. As shown in FIG. 3E, the relationship between the virgin material area ratio and the mixing ratio of the pulverized material is obtained in advance and stored in the memory (non-volatile memory) of the analysis processing unit 54. Based on the relationship stored in this memory, the mixing ratio of the pulverized material corresponding to the virgin material area ratio is obtained, and a series of processes for determining the mixing ratio are completed.

[0051] FIG. 4 is a flowchart showing the flow of the alarm output determination process.

[0052] In the analysis processing unit 54, when the mixing ratio of the pulverized material is determined (step S11), it is determined whether or not the mixing ratio is within a predetermined range (step S12).

[0053] When the mixing ratio of the pulverized material is within the predetermined range (YES in step S12), it is assumed that the mixing ratio of the pulverized material is normal, and the alarm output determination process is terminated.

[0054] On the other hand, when the mixing ratio of the pulverized material is not within the predetermined range (NO in step S12), it is assumed that the mixing ratio of the pulverized material is abnormal, and an alarm (display, sound) for notifying the abnormality is output (step S13), and the alarm output determination process is terminated.

[0055] Note that the mixed material may include a powder such as a masterbatch containing a pigment or an additive, and is often a different color from the main material. For such a differently colored powder, in the analysis processing unit 54, as shown in FIG. 5, the mixing ratio can be determined by executing the processes of steps S14 and S15 in parallel with the processes of steps S2 to S9 described above.

[0056] That is, a specific color (confirmation color) designated for the captured image is extracted (step S14: confirmation color extraction). The confirmation color is made available for reference by the analysis processing unit 54, such as by being input by the operator or being stored in advance. Also, a basic calibration line showing the relationship between the actual mixing ratio of the powder particles having the confirmation color and the pixel number ratio of the confirmation color in the captured image is created in advance. This calibration line is obtained and stored by methods such as through preliminary experiments or trial operations. The analysis processing unit 54 extracts the pixels corresponding to the confirmation color from the captured image and calculates the total number of pixels of the confirmation color. Then, the pixel number ratio of the confirmation color with respect to the total number of pixels of the captured image is obtained (S15: calculation of the area ratio of the designated color). The total area ratio of the confirmation color is compared with the calibration line, and the mixing ratio of the powder particles of the confirmation color is estimated based on the total area of the confirmation color.

[0057] Thereby, even when the mixed material contains not only virgin materials and crushed materials but also powder particles of different colors, the mixing ratio can be separately obtained. Note that the step of obtaining the ratio of the confirmation color may be omitted when there are no powder particles of different colors or when it is not necessary.

[0058] <Operational effects> As described above, even when the virgin material and the crushed material have the same color but different shapes and their powder particles are included in the mixed material, the mixing ratio of the crushed material as an example of a specific type of powder particles can be determined.

[0059] <Other embodiments> FIG. 6 is a diagram schematically showing the configuration of a system 2 in which a mixing ratio determination device 101 according to another embodiment of the present invention is incorporated. In FIG. 6, parts corresponding to the respective parts shown in FIG. 1 are given the same reference numerals as those parts. Also, hereinafter, the description of the parts given the same reference numerals will be omitted.

[0060] The mixing ratio determination device 101 is incorporated into the system 2 for manufacturing resin molded products, similar to the mixing ratio determination device 1 according to the foregoing embodiment, and is a device for determining the mixing ratio of specific types of powder particles in the mixing material used for the manufacturing. In the mixing ratio determination device 101, the light source 52 is arranged on the side opposite to the imaging device 53 with respect to the observation unit 51, and the mixing material passing through the inside of the observation unit 51 is irradiated with illumination light from the opposite side. The illumination light (transmitted light) that has passed through the mixing material is incident on the imaging device 53, and in the analysis processing unit 54, an image of the transmitted light incident on the imaging device 53 is acquired as a captured image (still image) of the mixing material.

[0061] FIG. 7 is a block diagram showing the functional configuration of the mixing ratio determination device 101.

[0062] For example, during a predetermined period while the mixing material transported from the metering and mixing device 3 by the transport device 4 is being fed into the molding machine 5, the mixing material passing through the inside of the observation window 58 is irradiated with illumination light from the light source 52. In parallel with this, the mixing material passing through the inside of the observation window 58 is photographed by the imaging device 53 at a constant frame rate. This process is an example of the photographing process. The illumination light (reflected light) reflected by the mixing material is incident on the imaging device 53, and in the analysis processing unit 54, an image of the reflected light incident on the imaging device 53 is acquired as a captured image (still image) of the mixing material. Then, in the analysis processing unit 54, the captured images of the mixing material acquired at a constant frame rate are stored in a memory (volatile memory) (S21: Image storage).

[0063] In the analysis processing unit 54, each of the processes described hereinafter is performed on each captured image stored in the memory.

[0064] As a first process, the captured image, which is a color image, is converted into a grayscale image (S22: Grayscale conversion). This process is an example of the grayscale process. The method of this conversion is well-known and will not be described here. FIG. 8A shows an example of a grayscale image.

[0065] As a second process, a process of removing Gaussian noise caused by reflected light of the illumination light of the light source 52 reflected from the mixed material from the grayscale image is performed (S23: noise removal). In this process of removing Gaussian noise, for example, a median filter, a Gaussian filter, an averaging filter, or the like is used. Since each of these filters is well-known, the description thereof is omitted here.

[0066] As a third process, the luminance value of each pixel of the grayscale image from which Gaussian noise has been removed is acquired, and the variance value of the luminance value is calculated according to the definition formula of variance (S24: acquisition of variance value of luminance). This step is an example of a variance value calculation step.

[0067] As a fourth process, a process of determining the mixing ratio of the pulverized material from the variance value of the luminance value is performed (S25: mixing ratio determination). The step in which this process is performed is an example of a determination step. In the memory (non-volatile memory) of the analysis processing unit 54, as shown in FIG. 8B, the relationship between the variance value of the luminance value and the mixing ratio of the pulverized material is stored. This relationship is obtained in advance, for example, by preparing a reference material in which the mixing ratio of the pulverized material is adjusted to a plurality of predetermined values, individually placing the reference material in the observation unit 51, photographing the reference material through the observation window 58 with the photographing device 53, and performing the above-described first to third processes to obtain the variance value of the luminance value corresponding to each mixing ratio. Based on the relationship stored in the memory, the mixing ratio of the pulverized material corresponding to the variance value of the luminance value is obtained, and a series of processes for determining the mixing ratio is completed.

[0068] Then, when the warning output determination process shown in FIG. 4 is executed and the mixing ratio of the pulverized material is not within a predetermined range (NO in step S12), it is determined that the mixing ratio of the pulverized material is abnormal, and a warning notifying the abnormality is output (step S13), and the warning output determination process ends.

[0069] Note that the mixed material may contain a granular material called a masterbatch that includes pigments and additives, and it is often a different color from the main material. For such a granular material of a different color, as shown in FIG. 9, the analysis processing unit 54 can determine the mixing ratio by executing the processes of steps S26 and S27 in parallel with the processes up to the aforementioned steps S22 to S24.

[0070] That is, a specific color (confirmation color) specified for the photographed image is extracted (step S26: confirmation color extraction). The analysis processing unit 54 extracts the pixels corresponding to the confirmation color from the photographed image and calculates the total number of pixels of the confirmation color. Then, the pixel number ratio of the confirmation color to the total number of pixels of the photographed image is obtained (S27: calculation of the area ratio of the specified color). The total area ratio of the confirmation color is compared with the comparison straight line, and the mixing ratio of the granular material of the confirmation color is estimated based on the total area of the confirmation color. Note that the confirmation color and the comparison straight line are as described with reference to FIG. 5.

[0071] Thereby, even when the mixed material contains not only virgin material and crushed material but also granular materials of a different color, the mixing ratio can be separately obtained. Note that the step of obtaining the ratio of the confirmation color may be omitted when no granular material of a different color is contained or when it is not necessary.

[0072] <Operational Effect> Also according to this embodiment, even when the virgin material and the crushed material are the same color and their granular materials are contained in the mixed material, the mixing ratio of the crushed material as an example of a specific type of granular material can be determined.

[0073] <Modification Example> As described above, the embodiments of the present invention have been described, but the present invention can also be implemented in other forms.

[0074] For example, in each of the foregoing embodiments, an example where the mixing ratio determination device 1, 101 is incorporated into the system 2 including the metering and mixing device 3 has been taken up. However, as shown in FIG. 10, the mixing ratio determination device 101 may be incorporated into the system 203 in which the in-machine mixer 202 is provided on the molding machine 201. The in-machine mixer 202 is configured such that granular materials (virgin materials, crushed materials) are supplied from a plurality of raw material hoppers 204 to the mixing section 205, and the mixed material obtained by mixing the plurality of supplied granular materials in the mixing section 205 is input from the mixing section 205 to the molding machine 201. Also, the mixing ratio determination device 1 may also be incorporated into the system 203 in which the in-machine mixer 202 is provided on the molding machine 201.

[0075] Also, in the mixing ratio determination device 1, the light source 52 is arranged on the side of the photographing device 53 with respect to the observation section 51, reflected light in the mixed material is incident on the photographing device 53, and in the analysis processing section 54, an image of the reflected light incident on the photographing device 53 is acquired as a photographed image of the mixed material. Not limited to this, similar to the mixing ratio determination device 101, the light source 52 is arranged on the side opposite to the photographing device 53 with respect to the observation section 51, the mixed material passing through the observation section 51 is illuminated by the illumination light from the opposite side, the transmitted light transmitted through the mixed material is incident on the photographing device 53, and in the analysis processing section 54, an image of the transmitted light incident on the photographing device 53 may be acquired as a photographed image of the mixed material. In this case, in the analysis processing section 54, processing with the content where black and white are inverted from the foregoing processing is performed.

[0076] Furthermore, similarly, in the mixing ratio determination device 101, the light source 52 is arranged on the side opposite to the photographing device 53 with respect to the observation section 51, the mixed material passing through the observation section 51 is illuminated by the illumination light from the opposite side, the transmitted light transmitted through the mixed material is incident on the photographing device 53, and in the analysis processing section 54, an image of the transmitted light incident on the photographing device 53 is acquired as a photographed image of the mixed material. However, similar to the mixing ratio determination device 1, the light source 52 is arranged on the side of the photographing device 53 with respect to the observation section 51, reflected light in the mixed material is incident on the photographing device 53, and in the analysis processing section 54, an image of the reflected light incident on the photographing device 53 may be acquired as a photographed image of the mixed material.

[0077] In step S24 shown in FIGS. 7 and 9, an integrated value may be obtained instead of the dispersion value of luminance. As a result, an integrated distribution as shown in FIG. 11 can be obtained. The horizontal axis represents the luminance value of pixels (for example, 0 to 255), and the vertical axis represents the ratio of the integrated number from 0 to each luminance to the total number of pixels. In this integrated distribution, it can be seen that the distribution shape varies according to the ratio of the pulverized material. In this case, for example, the integrated pixel number (% and the position on the vertical axis) where the luminance difference is large according to the mixing ratio is selected from the integrated distribution, and the mixing ratio can be estimated by comparing the luminance at that position with a reference value prepared in advance. The data serving as the reference value can be obtained by photographing a plurality of samples having known mixing ratios. For example, an integrated luminance distribution as shown in FIG. 11 is obtained for a target image with an unknown mixing ratio, and the luminance at the position on the vertical axis where the integrated pixel number is 30% is read. At this time, the mixing ratio of the target image can be estimated by comparing it with the luminance at the reference value obtained in advance under the condition that the pixel number is 30%.

[0078] In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims of the patent.

Explanation of Signs

[0079] 1: Mixing ratio determination device 5,201: Molding machine (predetermined equipment) 51: Observation unit 53: Photographing equipment 54: Analysis processing unit 58: Observation window 101: Mixing ratio determination device

Claims

1. A photographing step of photographing a mixed material in which a plurality of types of powder materials having different appearances are mixed with a photographing device to obtain a color image of the mixed material; A grayscale step of converting the color image obtained in the photographing step into a grayscale image; An evaluation value calculation step of obtaining the luminance of each pixel of the grayscale image after the grayscale step and calculating a dispersion value or an integrated value of the obtained luminance; A determination step of determining the mixing ratio of a specific type of the powder material from the dispersion value or the integrated value calculated in the evaluation value calculation step; An estimation step of extracting pixels corresponding to a pre-specified confirmation color from the image obtained in the photographing step, obtaining the total area of the confirmation color from the total number of pixels of the confirmation color, and estimating the mixing ratio of the powder material of the confirmation color based on the total area of the confirmation color. The mixing ratio determination method includes these steps.

2. The mixing ratio determination method according to claim 1, wherein in the photographing step, illumination light is irradiated on the mixed material from the side opposite to the photographing device side.

3. Further including a charging step of charging the mixed material into a predetermined device, In the photographing step, the mixed material charged into the predetermined device in the charging step is photographed with the photographing device. The mixing ratio determination method according to claim 1 or 2.

4. The mixed material includes a virgin material and a pulverized material of resin. The mixing ratio determination method according to any one of claims 1 to 3.

5. An observation unit having an observation window for observing the inside, into which a mixed material in which a plurality of types of powder materials having different appearances are mixed is supplied; A photographing device that photographs the mixed material supplied to the observation unit through the observation window; An analysis processing unit that analyzes the color image photographed by the photographing device, The analysis processing unit, A grayscale process of converting the color image into a grayscale image; An evaluation value calculation process of obtaining the luminance of each pixel of the grayscale image after the grayscale process and calculating a dispersion value or an integrated value of the obtained luminance; A determination process of determining the mixing ratio of a specific type of the powder material from the dispersion value or the integrated value calculated in the evaluation value calculation process; An estimation process of extracting pixels corresponding to a pre-specified confirmation color from the image photographed by the photographing device, obtaining the total area of the confirmation color from the total number of pixels of the confirmation color, and estimating the mixing ratio of the powder material of the confirmation color based on the total area of the confirmation color. The mixing ratio determination device executes these processes.

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