JP7708467B2 - Mixture ratio determination method and mixture ratio determination device - Google Patents

Description

The present invention relates to a mixture ratio determination method and a mixture ratio determination device.

A material that is a mixture of powdered materials such as pellet-shaped virgin material, crushed material for recycling, and pigments in a specified ratio is fed into a molding machine that manufactures resin molded products. Methods for feeding the mixed material include, for example, a method in which a mixture of multiple types of powdered materials is fed into the molding machine beforehand, and a method in which multiple types of powdered materials are mixed and fed into the molding machine.

Regardless of the method used, due to segregation and separation of powders and variations in blending accuracy, it is not possible to be sure that the powders are mixed in the specified ratio in the mixed material just before it is fed into the molding machine. The mixture ratio of powders in the mixed material is related to the quality of the plastic molded product, and if it can be determined that the mixture ratio is the specified ratio, it will be possible to adjust or stop the process before an abnormality occurs and produce a large number of defective products, which will contribute to the production yield of plastic molded products.

Therefore, a method has been proposed in which a mixed material consisting of multiple types of powders and granules of different colors is photographed to obtain multiple photographed images, the ratio of the total number of pixels having one type of powder color to the total number of pixels contained in the multiple photographed images is calculated as the actual area ratio, and the mixture ratio of the powders and granules is determined based on the actual area ratio (see, for example, Patent Document 1).

JP 2019-60805 A

However, this method cannot distinguish between different types of powders and granules of the same color (multiple types of powder and granules). A material that is a mixture of virgin material and recycled crushed material is sometimes used for resin molding, and it is difficult to determine the mixing ratio of the powders and granules in such a mixed material.

The object of the present invention is to provide a method and device for determining the mixing ratio of a specific type of powder or granular material in a material in which different types of powder or granular material of the same color are mixed.

In order to achieve the above object, a method for determining a mixture ratio according to one aspect of the present invention includes a photographing step of photographing a mixed material, which is a mixture of multiple types of powders and granules having different appearances, 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 on a powder and granule basis, an identification step of identifying each image region divided in the region dividing step from the shape of its outline, and a determination step of determining the mixture ratio of a specific type of powder and granule from the identification result in the identification step.

This method makes it possible to determine the mixing ratio of a specific type of powder, even if the mixed material contains powders of the same color but different shapes.

The method can be implemented by a mixing ratio determination device that includes an observation section having an observation window for observing the inside and into which a mixed material made of a mixture of multiple types of powders and granules with different appearances is supplied, a photographing device that photographs the mixed material supplied to the observation section through the observation window, and an analysis processing section that analyzes the image photographed by the photographing device, and the analysis processing section performs an area division process that divides the image into areas on a powder and granule unit basis, an identification process that identifies each image area divided by the area division process from the shape of its outline, and a determination process that determines the mixing ratio of a specific type of powder and granule from the identification result by the identification process.

Before the region division process, a binarization process may be further included in which the image acquired in the photographing process is binarized.

The image acquired in the photographing process may be a color image, and may further include a grayscale process for converting the color image acquired in the photographing process into a grayscale image before the binarization process, an averaging process for averaging the grayscale images after the grayscale process, and an irregularity removal process for removing irregularities in the background from the color image acquired in the photographing process using the grayscale image after the averaging process.

Before the region division step, an inversion step may be further included in which the black and white of a region of a certain area or less in the image binarized in the binarization step is inverted.

The method may further include a padding step, which is performed after the inversion step and before the identification step, for padding each image region divided in the region division step.

In the photographing process, illumination light may be irradiated onto the mixed material from the photographing device. In this configuration, illumination light (reflected light) reflected from the mixed material is incident on the photographing device, and an image of the reflected light incident on the photographing device is obtained as a photographed image of the mixed material.

A method for determining the mixture ratio according to another aspect of the present invention includes a photographing step of photographing a mixed material, which is a mixture of multiple types of powders and granules having different appearances, 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 brightness of each pixel in the grayscale image after the grayscale step and calculating a variance value or an integrated value of the obtained brightness, and a determination step of determining the mixture ratio of a specific type of powder and granule from the variance value or integrated value calculated in the evaluation value calculation step.

When a mixed material contains powders of the same color but different types, this method makes it possible to determine the mixing ratio of a specific type of powder, regardless of the shape of the powders.

The method can be implemented by a mixing ratio determination device that includes an observation section having an observation window for observing the inside and into which a mixed material made of a mixture of multiple types of powders and granules with different appearances is supplied, a photographing device that photographs the mixed material supplied to the observation section through the observation window, and an analysis processing section that analyzes the color image photographed by the photographing device, and the analysis processing section performs a grayscale process that converts the color image into a grayscale image, an evaluation value calculation process that acquires the luminance of each pixel of the grayscale image after the grayscale process and calculates a variance value or an integrated value of the acquired luminance, and a determination process that determines the mixing ratio of a specific type of powder or granule from the variance value or integrated value calculated in the evaluation value calculation process.

In the photographing process, the mixed material may be irradiated with illumination light from the side opposite to the photographing device. In this configuration, the illumination light (transmitted light) that has passed through the mixed material is incident on the photographing device, and the image of the transmitted light that has entered the photographing device is obtained as a photographed image of the mixed material.

The method may further include a step of feeding the mixed material into a specified device, and in the photographing step, the mixed material to be fed into the specified device in the feeding step may be photographed by a photographing device. This makes it possible to determine the mixing ratio of a specific type of powder or granular material in the mixed material to be fed, immediately before the mixed material is fed into the specified device.

The present invention makes it possible to determine the mixing ratio of a specific type of powder in a material that contains different types of powder of the same color, such as powder of the same color but different shapes.

1 is a diagram illustrating the configuration of a system incorporating a mixing ratio determination device according to an embodiment of the present invention. 2 is a block diagram showing a functional configuration of the mixture ratio determination device shown in FIG. 1 . FIG. 13 is a diagram showing an example of a black-and-white image after filling processing. FIG. 13 is a diagram showing an example of a black-and-white image divided into regions on a powder/particle basis. FIG. 1 is a diagram showing an example of a workpiece (virgin material) having a degree of unevenness less than a predetermined value. FIG. 1 is a diagram showing an example of a workpiece (virgin material) having a degree of unevenness equal to or greater than a predetermined value. FIG. 13 is a diagram showing an example of the relationship between the area ratio of virgin material and the mixing ratio of pulverized material. 10 is a flowchart showing a flow of a warning output determination process. 1. FIG. 4 is a block diagram showing another example of the functional configuration of the mixing ratio determination device shown in FIG. FIG. 13 is a diagram illustrating the configuration of a system 2 incorporating a mixture ratio determination device according to another embodiment of the present invention. FIG. 7 is a block diagram showing a functional configuration of the mixture ratio determination device shown in FIG. 6 . FIG. 1 is a diagram illustrating an example of a grayscale image. FIG. 13 is a diagram showing an example of the relationship between the variance value of the brightness value and the mixing ratio of the pulverized material. 7 is a block diagram showing another example of the functional configuration of the mixing ratio determination device shown in FIG. 6 . FIG. 1 is a diagram illustrating a system configuration in which an on-machine mixer is provided on a molding machine. FIG. 13 is a diagram showing an example of the distribution of integrated brightness values (integrated brightness value distribution example) when the mixing ratio of crushed material is 10%, 30%, and 50%.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

<Resin molded product manufacturing equipment>
FIG. 1 is a diagram illustrating the configuration of a production facility 2 in which a mixing ratio determination device 1 according to an embodiment of the present invention is incorporated.

The mixing ratio determination device 1 is incorporated into manufacturing equipment 2 that produces resin molded products, and is a device that determines the mixing ratio of a specific type of powder or granular material in the mixed material used in the production. The mixed material is a material in which multiple types of powder or granular material, such as virgin material, crushed material, and pigments, are mixed in a predetermined ratio. In addition to the mixing ratio determination device 1, the system 2 includes a metering and mixing device 3 that measures and mixes various types of powder or granular material, a transport device 4 that transports the mixed material from the metering 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 fed.

The metering and mixing device 3 includes a raw material supply section 11, a metering section 12, and a mixing section 13.

The raw material supply section 11 is provided with multiple raw material hoppers 21, each of which stores different types of powdered or granular materials. The raw material powdered or granular materials are supplied to each raw material hopper 21 by pneumatic transport from a raw material tank (not shown). Each raw material hopper 21 is also provided with a screw feeder 22. The powdered or granular materials stored in the raw material hopper 21 are discharged from the raw material hopper 21 by the operation of the screw feeder 22.

The weighing section 12 is provided with a weighing hopper 23, which receives the powdered material discharged from each raw material hopper 21. 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 that opens and closes the discharge outlet at the lower end. The weighing hopper 23 is also provided with a load cell 25 for measuring the mass of the powdered material stored in the weighing hopper 23.

When the screw feeder 22 of the raw material hopper 21 that stores the powder to be weighed starts operating with the gate shutter 24 closed, the powder discharged from the raw material hopper 21 is stored in the weighing hopper 23. The powder stored in the weighing hopper 23 is weighed by the load cell 25 while the screw feeder 22 of the raw material hopper 21 continues to operate, and when the fixed amount is measured by the load cell 25, the operation of the screw feeder 22 is stopped. By controlling the operation of the screw feeders 22 of each raw material hopper 21 in sequence, multiple types of powder mixed at a predetermined ratio (proportion) are stored in the weighing hopper 23. When the gate shutter 24 is opened in this state, the multiple types of powder stored in the weighing hopper 23 are discharged from the discharge port.

The mixing section 13 is disposed below the measuring section 12. The mixing section 13 includes a mixing container 31, an agitating 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.

With the shutter valve 34 closed, the powder discharged from the discharge port of the weighing hopper 23 of the weighing section 12 is received by the mixing container 31, and the powder is stored in the mixing container 31. When the motor 32 is driven and the agitator blade 33 rotates, the multiple types of powder in the mixing container 31 are mixed. When the powder in the mixing container 31 is sufficiently mixed, the shutter valve 34 is opened. When the shutter valve 34 is opened, the mixed material consisting of the mixed multiple types of powder is discharged from the discharge port of the mixing container 31.

The transport device 4 is equipped with a supply hopper 41 disposed below the mixing vessel 31. The mixed material discharged from the discharge outlet of the mixing vessel 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 outlet at the lower end 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.

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

<Mixing ratio determination device>
The mixture ratio determination device 1 includes an observation unit 51 having an observation window 58, a light source 52, a photographing device 53, and an analysis processing unit .

The observation section 51 is interposed between the loader hopper 44 and the molding machine 5, and has a space 55 therein through which the mixed material fed from the loader hopper 44 to the molding machine 5 passes. The observation section 51 has a front plate 56 and a back plate 57 that face each other in parallel with the space 55 in between. The front plate 56 and the back plate 57 are, for example, of the same configuration and made of a translucent plate-like body (resin plate, glass plate). The front plate 56 and the back plate 57 are joined to each other at their peripheries, and an inlet and an outlet for introducing the mixed material are formed between their upper and lower ends, respectively. In addition, no light-blocking member is arranged in the center surrounded by the peripheries of the front plate 56 and the back plate 57, and the center of the front plate 56 functions as an observation window 58 that allows the mixed material passing through the observation section 51 to be observed from the outside.

The light source 52 is a generally rectangular plate and is disposed facing the front plate 56 from the side opposite the back plate 57. The center of the light source 52 is formed as a rectangular opening, or the opening is closed with a colorless and transparent light guide plate. The periphery of the light source 52 is provided with an LED array in which multiple LEDs (Light Emitting Diodes) are arranged in a line, and a reflector that reflects the light of each LED toward the front plate 56, 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.

The photographing device 53 is a camera equipped with a lens and an image sensor, and capable of continuously photographing color still images at a predetermined frame rate. The photographing device 53 is positioned away from the light source 52 on the opposite side to the observation section 51, with its optical axis perpendicular to the observation window 58, so that it can photograph the mixed material passing through the observation section 51 through the center of the light source 52 and the observation window 58. Other optical components such as a magnifying/reducing lens and a polarizing plate may also be used in combination.

The analysis processing unit 54 is a device that analyzes the images captured by the photographing device 53, and is composed of a computer that operates according to a program for that analysis. The computer has a built-in CPU and memory. The memory includes non-volatile memory such as flash memory and volatile memory such as DRAM (Dynamic Random Access Memory).

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

In the mixing ratio determination device 1, for example, the mixed material passing through the observation window 58 is illuminated with illumination light from the light source 52 for a predetermined period during the period during which the mixed material transported from the metering and mixing device 3 by the transport device 4 is fed into the molding machine 5. In parallel with this, the mixed material passing through the observation window 58 is photographed at a constant frame rate by the photographing device 53. The illumination light (reflected light) reflected by the mixed material is incident on the photographing device 53, and the image of the reflected light incident on the photographing device 53 is acquired as a photographed image (still image) of the mixed material by the analysis processing unit 54. This process is an example of a photographing process. Then, the photographed image of the mixed material acquired at a constant frame rate is stored in memory (volatile memory) by the analysis processing unit 54 (S1: image storage).

The analysis processing unit 54 performs the processes described below on each captured image stored in memory.

As the first process, a process for removing background unevenness due to uneven lighting, etc. is performed (S2: Background unevenness removal). In this process for removing background unevenness, the photographed image, which is a color image, is first converted into a grayscale image. This conversion method is well known, and will not be described here. Next, an averaging process (average filter process) is performed to average the grayscale image. In the averaging process, an averaging filter is used, and for example, each pixel of the grayscale image is set as a pixel of interest, and the average value of the luminance values of each pixel included in a predetermined area centered on the image of interest is calculated. The luminance value of the pixel of interest is then replaced with this average value. This averaging process can reduce the difference in luminance values between pixels due to noise. Then, the luminance value of the grayscale image after the averaging process is subtracted from the luminance value of the photographed image, and the average luminance value of each pixel of the photographed image is added to the subtracted value, thereby obtaining an image from which background unevenness has been removed.

The second process is to remove Gaussian noise caused by a process of compensating for a lack of light from the illumination light of the light source 52 (S3: noise removal). In this process of removing Gaussian noise, for example, a median filter, a Gaussian filter, or an averaging filter is used. Each of these filters is well known, so a description of them will be omitted here.

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

As a fourth process, a hole filling process is performed to repair "missing" particles contained in the captured image (black and white image) after the binarization process (S5: hole filling). This hole filling process is performed in the determination process, and in this hole filling process, a labeling process is first performed. The labeling process is, for example, a process of assigning the same number to consecutive white pixels in four directions (vertical and horizontal) or eight directions (vertical, horizontal and diagonal). Next, the area of the part that is assigned the same number is calculated, and for parts that are less than a certain area, the white pixels in that part are inverted to black pixels. An example of a black and white image after hole filling is shown in Figure 3A.

As the fifth process, the black-and-white image after the filling process is divided into regions of powder and granular material (work) (S6: work region division). This process of region division is an example of a region division process, and in this process, for example, a watershed transformation algorithm is used. First, an erosion process is performed to shrink the region (region to be divided) in which white pixels are collected in the black-and-white image. Next, a distance transformation process is performed to determine the region near the center of each region to be divided after the erosion process. In the distance transformation process, the luminance value of each pixel in the region to be divided is converted so that pixels far from the background (region of black pixels) become white and images close to the background become black, and the pixels are binarized so that the region near the center remains. After that, a region that is neither the region near the center (foreground) nor the background is extracted from the entire image region. In addition, 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 the foreground nor the background is set as a white pixel. This results in a black-and-white image divided into powder and granular regions, as shown in Figure 3B.

As the sixth process, a process for identifying the workpiece is performed (S7: Identification of workpiece). The process in which this process is performed is an example of an identification process, and in this process, in the black-and-white image after the region division process, a number is first assigned to the region (workpiece) where white pixels are collected, and each workpiece is individually identified by a labeling process. Next, for each workpiece, the coordinates of each vertex of the rectangle circumscribing the workpiece are obtained, and the image of the rectangular region is cut out. Then, a zero padding process is performed on the cut-out image, in which the brightness value of the pixels surrounding the workpiece is set to "0". The process in which this zero padding process is performed is an example of a padding process. Also, if there are multiple regions of collected white pixels in the image within the rectangular region, the brightness values of the pixels other than the region with the largest area among them are set to "0".

As the seventh process, the degree of unevenness of the contour of each identified workpiece is calculated (S8: Calculate degree of unevenness). The degree of unevenness is calculated, for example, by measuring the actual perimeter of the workpiece and the envelope perimeter of the workpiece (a straight line connecting the end points of the convex parts of the particles) and dividing the measured perimeter by the envelope perimeter.

As the eighth process, a process for determining the type of work (powder or granular material) is performed (S9: Work type determination). The process in which this work type determination process is performed is an example of a determination process, in which work is separated into work whose unevenness is less than a predetermined level and work whose unevenness is equal to or greater than a predetermined level. Then, as shown in FIG. 3C, work whose unevenness is less than a predetermined level is determined to be virgin material, and as shown in FIG. 3D, work whose unevenness is equal to or greater than a predetermined level is determined to be pulverized material.

As the ninth process, a process for 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 (white pixels) representing the virgin material 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 determined and stored in advance 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 according to the virgin material area ratio is determined, and a series of processes for determining the mixing ratio is terminated.

Figure 4 is a flowchart showing the flow of the warning output determination process.

In the analysis processing unit 54, when the mixing ratio of the crushed material is determined (step S11), it is determined whether the mixing ratio is within a predetermined range (step S12).

If the mixing ratio of the crushed material is within the specified range (YES in step S12), the mixing ratio of the crushed material is determined to be normal and the warning output determination process is terminated.

On the other hand, if the mixing ratio of the crushed material is not within the predetermined range (NO in step S12), the mixing ratio of the crushed material is determined to be abnormal, and an alarm (visual display, sound) is output to notify the abnormality (step S13), and the alarm output determination process is terminated.

The mixed material may contain a powder called a master batch, which contains pigments and additives, and is often a different color from the main material. For such powders of a different color, the analysis processing unit 54 can determine the mixing ratio by executing the processes of steps S14 and S15 in parallel with the processes of steps S2 to S9 described above, as shown in FIG. 5.

That is, a specific color (confirmation color) designated for the captured image is extracted (step S14: Extract confirmation color). The confirmation color is input by the operator or stored in advance so that the analysis processing unit 54 can refer to it. A basic calibration line is created in advance to show the relationship between the actual mixing ratio of powder and granular material having the confirmation color and the pixel number ratio of the confirmation color in the captured image. This calibration line is obtained and stored by a method such as obtaining it through a preliminary experiment or a test run. The analysis processing unit 54 extracts pixels corresponding to the confirmation color from the captured image and calculates the total pixel number of the confirmation color. Then, the pixel number ratio of the confirmation color to the total pixel number of the captured image is calculated (S15: Calculate area ratio of designated color). The total area ratio of the confirmation color is compared with the comparison line, and the mixing ratio of the powder and granular material of the confirmation color is estimated based on the total area of the confirmation color.

This makes it possible to determine the mixing ratio separately even if the mixed material contains not only virgin material and crushed material but also powders and granules of different colors. Note that if powders and granules of different colors are not included or are not necessary, the process of determining the ratio of the confirmation colors may be omitted.

<Action and effect>
As described above, even if virgin material and pulverized material are the same color but have different shapes, and these powder particles are contained in a mixed material, the mixing ratio of pulverized material as an example of a specific type of powder particle can be determined.

<Other embodiments>
Fig. 6 is a diagram illustrating the configuration of a system 2 incorporating a mixture ratio determination device 101 according to another embodiment of the present invention. In Fig. 6, parts corresponding to those shown in Fig. 1 are given the same reference numerals as those parts. In the following, explanations of parts given the same reference numerals will be omitted.

The mixing ratio determination device 101, like the mixing ratio determination device 1 according to the embodiment described above, is incorporated into a system 2 for manufacturing a resin molded product, and is a device for determining the mixing ratio of a specific type of powder or granular material in a mixed material used in the manufacture of the product. In the mixing ratio determination device 101, a light source 52 is disposed on the opposite side of the observation section 51 to the photographing device 53, and the mixed material passing through the observation section 51 is irradiated with illumination light from the opposite side, and the illumination light (transmitted light) that has passed through the mixed material enters the photographing device 53, and an image of the transmitted light that has entered the photographing device 53 is acquired as a photographed image (still image) of the mixed material in the analysis processing section 54.

Figure 7 is a block diagram showing the functional configuration of the mixing ratio determination device 101.

In the mixing ratio determination device 101, for example, the mixed material passing through the observation window 58 is irradiated with illumination light from the light source 52 for a predetermined period during the period during which the mixed material transported from the metering and mixing device 3 by the transport device 4 is fed into the molding machine 5. In parallel with this, the mixed material passing through the observation window 58 is photographed at a constant frame rate by the photographing device 53. This process is an example of a photographing process. The illumination light (reflected light) reflected by the mixed material is incident on the photographing device 53, and the analysis processing unit 54 acquires an image of the reflected light incident on the photographing device 53 as a photographed image (still image) of the mixed material. Then, the analysis processing unit 54 stores the photographed image of the mixed material acquired at a constant frame rate in memory (volatile memory) (S21: image storage).

The analysis processing unit 54 performs the processes described below on each captured image stored in memory.

As a first process, the captured image, which is a color image, is converted into a grayscale image (S22: grayscaling). This process is an example of a grayscale process. This conversion method is well known, and a description thereof will be omitted here. An example of a grayscale image is shown in FIG. 8A.

As the second process, a process is performed to remove Gaussian noise from the grayscale image, which is caused by the illumination light from the light source 52 reflected by the mixed material (S23: noise removal). In the process of removing Gaussian noise, for example, a median filter, a Gaussian filter, or an averaging filter is used. Each of these filters is well known, so a description of them will be omitted here.

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

As the fourth process, a process is performed to determine the mixing ratio of the crushed material from the variance of the brightness values (S25: Mixing ratio determination). The process in which this process is performed is an example of a determination process. As shown in FIG. 8B, the memory (non-volatile memory) of the analysis processing unit 54 stores the relationship between the variance of the brightness values and the mixing ratio of the crushed material. This relationship is determined in advance, for example, by preparing a reference material in which the mixing ratio of the crushed material is adjusted to a plurality of predetermined values, placing the reference material individually in the observation unit 51, photographing the reference material through the observation window 58 with the photographing device 53, and performing the above-mentioned first to third processes to determine the variance of the brightness values corresponding to each mixing ratio. Based on the relationship stored in the memory, the mixing ratio of the crushed material according to the variance of the brightness values is determined, and a series of processes for determining the mixing ratio is completed.

Then, the alarm output determination process shown in FIG. 4 is executed, and if the mixing ratio of the crushed material is not within the predetermined range (NO in step S12), the mixing ratio of the crushed material is determined to be abnormal, and an alarm is output to notify the abnormality (step S13), and the alarm output determination process is terminated.

The mixed material may contain a powder called a master batch, which contains pigments and additives, and is often a different color from the main material. For such powders of a different color, the analysis processing unit 54 can determine the mixing ratio by executing the processes of steps S26 and S27 in parallel with the processes of steps S22 to S24 described above, as shown in FIG. 9.

That is, a specific color (confirmation color) designated for the captured image is extracted (step S26: Extract confirmation color). The analysis processing unit 54 extracts pixels corresponding to the confirmation color from the captured image and calculates the total number of pixels of the confirmation color. Then, the ratio of the number of pixels of the confirmation color to the total number of pixels of the captured image is obtained (S27: Calculate area ratio of designated color). The total area ratio of the confirmation color is compared with the comparison straight line, and the mixing ratio of the powder and 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.

This makes it possible to determine the mixing ratio separately even if the mixed material contains not only virgin material and crushed material but also powders and granules of different colors. Note that if powders and granules of different colors are not included or are not necessary, the process of determining the ratio of the confirmation colors may be omitted.

<Action and effect>
Even in this embodiment, even if the virgin material and the pulverized material are the same color and these powder particles are contained in a mixed material, the mixing ratio of the pulverized material as an example of a specific type of powder particle can be determined.

<Modification>
Although the embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, in each of the above-mentioned embodiments, the mixing ratio determination device 1, 101 is incorporated in a system 2 equipped with a metering and mixing device 3, but the mixing ratio determination device 101 may be incorporated in a system 203 in which an on-board mixer 202 is provided on a molding machine 201, as shown in FIG. 10. The on-board mixer 202 is configured such that powdered material (virgin material, crushed material) is supplied from a plurality of raw material hoppers 204 to a mixing section 205, and the supplied powdered material is mixed in the mixing section 205 to produce a mixed material, which is then fed from the mixing section 205 to the molding machine 201. The mixing ratio determination device 1 may also be incorporated in a system 203 in which an on-board mixer 202 is provided on a molding machine 201.

In addition, in the mixing ratio determination device 1, the light source 52 is disposed on the side of the photographing device 53 with respect to the observation unit 51, and the reflected light from the mixed material is incident on the photographing device 53, and the image of the reflected light incident on the photographing device 53 is acquired as a photographed image of the mixed material in the analysis processing unit 54. However, similarly to the mixing ratio determination device 101, the light source 52 may be disposed on the opposite side of the photographing device 53 with respect to the observation unit 51, and the mixed material passing through the observation unit 51 is illuminated with illumination light from the opposite side, and the transmitted light that has passed through the mixed material is incident on the photographing device 53, and the analysis processing unit 54 may acquire an image of the transmitted light that has entered the photographing device 53 as a photographed image of the mixed material. In this case, the analysis processing unit 54 performs processing that is the same as the above-mentioned processing with black and white inverted.

Furthermore, in the mixing ratio determination device 101, the light source 52 is disposed on the opposite side of the observation section 51 to the photographing device 53, the mixed material passing through the observation section 51 is illuminated with illumination light from the opposite side, the transmitted light that passes through the mixed material is incident on the photographing device 53, and the analysis processing section 54 acquires an image of the transmitted light that is incident on the photographing device 53 as a photographed image of the mixed material. However, as in the mixing ratio determination device 1, the light source 52 may be disposed on the side of the photographing device 53 relative to the observation section 51, the reflected light from the mixed material is incident on the photographing device 53, and the analysis processing section 54 acquires an image of the reflected light that is incident on the photographing device 53 as a photographed image of the mixed material.

In step S24 shown in FIG. 7 and FIG. 9, an integrated value may be obtained instead of the variance value of the brightness. This results in an integrated distribution as shown in FIG. 11. The horizontal axis indicates the brightness value of the pixel (for example, 0 to 255), and the vertical axis indicates the integrated number from 0 to each brightness as a percentage of the total number of pixels. In this integrated distribution, it can be seen that the distribution shape differs depending on the percentage of crushed material. In this case, for example, the integrated pixel number (%, vertical axis position) where the difference in brightness is large depending on the mixture ratio in the integrated distribution is selected, and the mixture ratio can be estimated by comparing the brightness at that position with a reference value prepared in advance. The reference value data can be obtained by creating and photographing multiple samples with known mixture ratios. As an example, an integrated brightness distribution as shown in FIG. 11 is obtained for a target image with an unknown mixture ratio, and the brightness at the vertical axis position where the integrated pixel number is 30% is read. At this time, the mixture ratio of the target image can be estimated by comparing it with the brightness at the reference value obtained in advance under the condition that the pixel number is 30%.

In addition, various design modifications can be made to the above-mentioned configuration within the scope of the claims.

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

Claims (5)

a photographing step of photographing a mixed material obtained by mixing a plurality of types of powder particles having different appearances with a photographing device to obtain a color image of the mixed material;
a grayscale process for converting the color image acquired in the photographing process into a grayscale image;
an evaluation value calculation step of acquiring a luminance value of each pixel of the grayscale image after the grayscale step, and calculating a variance value or an integrated value of the acquired luminance value;
a determination step of determining a mixing ratio of a specific type of powder or granular material from the variance value or the integrated value calculated in the evaluation value calculation step;
a step of extracting pixels corresponding to a pre-specified confirmation color from the image acquired in the photographing step, calculating a total area of the confirmation color from the total number of pixels of the confirmation color, and estimating a mixing ratio of powder or granular material of the confirmation color based on the total area of the confirmation color . The method for determining a mixture ratio according to claim 1, wherein in the photographing step, illumination light is irradiated onto the mixed material from the side opposite the photographing device. The mixed material is further introduced into a predetermined device.
3. The method according to claim 1, wherein in the photographing step, the mixed material poured into the predetermined device in the pouring step is photographed by the photographing device. The method for determining a mixture ratio according to any one of claims 1 to 3, wherein the mixed material includes virgin resin and crushed resin. an observation section having an observation window for observing the inside thereof, into which a mixed material containing a plurality of types of powder particles having different appearances is supplied;
an imaging device that images the mixed material supplied to the observation section through the observation window;
An analysis processing unit that analyzes the color image captured by the photographing device,
The analysis processing unit includes:
a grayscale process for converting the color image into a grayscale image;
an evaluation value calculation process for obtaining a luminance value of each pixel of the grayscale image after the grayscale processing and calculating a variance value or an integrated value of the obtained luminance values;
a determination process for determining a mixing ratio of a specific type of powder or granular material from the variance value or the integrated value calculated in the evaluation value calculation process;
a mixing ratio determination device that executes an estimation process of extracting pixels corresponding to a pre-specified confirmation color from the image captured by the photographing device, calculating a total area of the confirmation color from the total number of pixels of the confirmation color, and estimating the mixing ratio of powder or granular material of the confirmation color based on the total area of the confirmation color.