Particle size measuring device, method, and program

Abstract

To provide a grain diameter measurement apparatus, method and program which can measure a grain diameter by recognizing only an object appearing on an upper part when the plurality of objects are piled up without extracting the spherical objects.SOLUTION: A grain diameter measurement apparatus D according to the present invention comprises: an imaging unit 1 which generates an image by imaging a plurality of spherical objects that are piled up; a binarizing processing unit 34 which generates a binarized image by binarizing the image generated by the imaging unit 1 on the basis of a luminance value; an extraction processing unit 38 which extracts a bright region in which the diameter of the bright region based on an area is within a prescribed range, and the circularity of the bright region is greater than a prescribed first threshold while the circularity of the bright region is greater than a prescribed second threshold from one or the plurality of bright regions in the binarized image generated by the binarizing processing unit 34; and an output unit 5 which outputs the diameter of the bright region extracted by the extraction processing unit 38 as the grain diameter of the object corresponding to the bright region extracted by the extraction processing unit 38.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a particle size measuring apparatus, a particle size measuring method, and a particle size measuring program for measuring the particle size in deposited spherical objects.

Background Art

[0002] Measurement of particle size is required in various fields that handle particulate raw materials and products, for example, for setting manufacturing conditions and quality evaluation. As an example, iron ore pellets, which are raw materials for blast furnaces, are produced by adding auxiliary raw materials and binders as needed to powdered iron ore, which is a pellet raw material, further adding a predetermined amount of moisture, granulating green pellets using a granulator, and drying and firing them. It is known that the particle size of green pellets varies due to fluctuations in granulation conditions such as the particle size, supply amount, and added moisture amount of the pellet raw material, and changes in the generation status of deposits in the granulator. On the other hand, the raw materials for blast furnaces are required to have a uniform pellet diameter in order to ensure air permeability in the blast furnace. Therefore, the particle size of the green pellets granulated by the granulator is measured (for example, Patent Document 1 and Patent Document 2, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, since the particles after granulation are conveyed to the next process or storage, it is preferable to measure the particle size of the particles during conveyance. In such a case, in a so-called sieve test, it is necessary to extract the particles during conveyance, which is not preferable. Further, since the particles during conveyance are usually deposited in several layers, when observed from above, the particles existing relatively lower appear smaller than their actual size. For this reason, it is preferable to identify only the particles exposed on the upper part, measure their particle size, and then represent the overall particle size.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a particle size measuring device, a particle size measuring method, and a particle size measuring program that can recognize only the objects exposed on the upper part and measure the particle size without extracting spherical objects when a plurality of the objects are deposited.

Means for Solving the Problems

[0006] As a result of various studies, the present inventor has found that the above object is achieved by the following present invention. That is, a particle size measuring device according to an aspect of the present invention includes an imaging unit that images a plurality of deposited spherical objects to generate an image, a binarization processing unit that binarizes the image generated by the imaging unit based on luminance values to generate a binarized image, and from one or a plurality of bright regions in the binarized image generated by the binarization processing unit, an extraction processing unit that extracts a bright region whose diameter based on the area is within a predetermined range, and the circularity of the bright region is greater than a predetermined first threshold value, and the circularity of the bright region is greater than a predetermined second threshold value, and an output unit that outputs the diameter of the bright region extracted by the extraction processing unit as the particle size of the object corresponding to the bright region extracted by the extraction processing unit. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The circularity is the multiplication result obtained by multiplying the division result obtained by dividing the area of the bright region by the square of the perimeter of the bright region by 4 times the circumference ratio.

[0007] Such a particle size measuring device measures the particle size of the objects based on an image of a plurality of deposited spherical objects, so there is no need to extract the objects as in the sieve test. The above particle size measuring device extracts a bright region whose diameter based on the area is within a predetermined range, the circularity of the bright region is greater than a predetermined first threshold value, and the roundness of the bright region is greater than a predetermined second threshold value. Therefore, when a plurality of the objects are deposited, only the objects exposed on the upper part can be recognized and the particle size can be measured.

[0008] In another aspect, the above particle size measuring device further includes an illumination unit that illuminates the plurality of objects.

[0009] Such a particle size measuring device further includes an illumination unit, so that the particle size can be measured under a certain illumination environment. Therefore, sufficient illuminance is ensured not only for a stationary subject but also for a situation where the subject is being conveyed or moving. By suppressing the exposure time during imaging (i.e., by increasing the shutter speed), a clear image can be generated and the variation in measurement accuracy can be reduced.

[0010] In another aspect, in the above particle size measuring device, before binarization by the binarization processing unit, it further includes a shading correction processing unit that performs shading correction on the image generated by the imaging unit.

[0011] Such a particle size measuring device further includes a shading correction processing unit, so that even when there is spatial unevenness in illuminance, the illuminance unevenness can be reduced and the particle size can be measured more accurately.

[0012] In another aspect, in the above particle size measuring device, before binarization by the binarization processing unit, it further includes a smoothing processing unit that smooths the image generated by the imaging unit.

[0013] Such a particle size measuring device further includes a smoothing processing unit, so that the luminance difference caused by the shape of the object surface, deposits, etc. can be reduced and the particle size can be measured more accurately.

[0014] In another aspect, in these above-described particle size measuring apparatuses, before extraction by the extraction processing unit, a separation processing unit is further provided for separating the bright region formed by connecting a plurality of spherical shapes into spherical bright regions.

[0015] Such a particle size measuring apparatus further includes a separation processing unit, so even if a plurality of spherical shapes are connected, they can be separated, and the particle size can be measured more accurately.

[0016] In another aspect, in these above-described particle size measuring apparatuses, before extraction by the extraction processing unit, an expansion processing unit is further provided for performing, one or more times, an expansion process of expanding the outer periphery of the bright region by a predetermined length in the radially outward direction.

[0017] Such a particle size measuring apparatus further includes an expansion processing unit. So, when the outer peripheral portion of an object is darkly imaged, it will be measured smaller than the actual size. However, even in such a case, since the outer periphery of the bright region is expanded, the particle size can be measured closer to the actual size.

[0018] In another aspect, in these above-described particle size measuring apparatuses, before extraction by the extraction processing unit, an ellipse approximation processing unit is further provided for deforming the shape of the bright region into the most approximate elliptical shape.

[0019] Such a particle size measuring apparatus further includes an ellipse approximation processing unit. So, for a plurality of deposited spherical objects, for the objects whose shapes are slightly overlapped and difficult to see, the shape can be restored by ellipse approximation, and the number of measurable objects can be increased.

[0020] A particle size measuring device according to another aspect of the present invention includes an image acquisition unit that acquires an image of a plurality of deposited spherical objects, a binarization processing unit that binarizes the image acquired by the image acquisition unit based on luminance values to generate a binarized image, and from one or more bright regions in the binarized image generated by the binarization processing unit, an extraction processing unit that extracts a bright region whose diameter based on area is within a predetermined range, and whose circularity is greater than a predetermined first threshold, and whose circularity is greater than a predetermined second threshold, and an output unit that outputs the diameter of the bright region extracted by the extraction processing unit as the particle size of the object corresponding to the bright region extracted by the extraction processing unit. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The circularity is the multiplication result obtained by multiplying the division result obtained by dividing the area of the bright region by the square of the perimeter length of the bright region by four times pi.

[0021] Such a particle size measuring device measures the particle size of the objects based on an image of a plurality of deposited spherical objects, so there is no need to extract the objects as in the sieve test. The above particle size measuring device extracts a bright region whose diameter based on area is within a predetermined range, and whose circularity is greater than a predetermined first threshold, and whose circularity is greater than a predetermined second threshold. Therefore, when a plurality of the objects are deposited, only the objects exposed at the top can be recognized and the particle size can be measured.

[0022] Another aspect of the present invention relates to a particle size measurement method, comprising: an imaging step of imaging a plurality of deposited spherical objects to generate an image; a binarization processing step of binarizing the image generated in the imaging step based on luminance values to generate a binarized image; an extraction processing step of extracting, from one or more bright regions in the binarized image generated in the binarization processing step, a bright region whose diameter based on the area is within a predetermined range, and whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value; and an output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of the object corresponding to the bright region extracted in the extraction processing step. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The roundness is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times the pi.

[0023] Another aspect of the present invention relates to a particle size measurement method, comprising: an image acquisition step of acquiring an image obtained by imaging a plurality of deposited spherical objects; a binarization processing step of binarizing the image acquired in the image acquisition step based on luminance values to generate a binarized image; an extraction processing step of extracting, from one or more bright regions in the binarized image generated in the binarization processing step, a bright region whose diameter based on the area is within a predetermined range, and whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value; and an output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of the object corresponding to the bright region extracted in the extraction processing step. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The roundness is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times the pi. This is a method executed by a computer.

[0024] Another aspect of the present invention relates to a particle size measurement program, which includes an image acquisition step of acquiring an image obtained by imaging a plurality of deposited spherical objects, a binarization processing step of binarizing the image acquired in the image acquisition step based on luminance values to generate a binarized image, and an extraction processing step of extracting, from one or more bright regions in the binarized image generated in the binarization processing step, a bright region whose diameter based on the area is within a predetermined range, whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value, and an output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of the object corresponding to the bright region extracted in the extraction processing step. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The roundness is a multiplication result obtained by multiplying a division result obtained by dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times the pi. It is a program executed by a computer.

[0025] Such a particle size measurement method and particle size measurement program measure the particle size of the object based on an image obtained by imaging a plurality of deposited spherical objects, so there is no need to extract the object as in the sieve test. The above particle size measurement method and particle size measurement program extract a bright region whose diameter based on the area is within a predetermined range, whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value. Therefore, when a plurality of the objects are deposited, only the object exposed on the upper part can be recognized and the particle size can be measured.

Advantages of the Invention

[0026] The particle size measurement device, particle size measurement method, and particle size measurement program according to the present invention can measure the particle size by recognizing only the object exposed on the upper part when a plurality of the spherical objects are deposited without extracting the spherical objects.

Brief Description of the Drawings

[0027]

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Mode for Carrying Out the Invention

[0028] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In each figure, components denoted by the same reference numerals are the same components, and the description thereof will be omitted as appropriate. In this specification, when referring to generically, reference numerals without subscripts are used, and when referring to individual components, reference numerals with subscripts are used.

[0029] The particle size measuring device in the embodiment is a device that measures the particle size of a plurality of spherical objects deposited. This particle size measuring device includes an imaging unit that images a plurality of spherical objects deposited to generate an image, a binarization processing unit that binarizes the image generated by the imaging unit based on luminance values to generate a binarized image, and from among one or more bright regions in the binarized image generated by the binarization processing unit, an extraction processing unit that extracts a bright region whose diameter based on area is within a predetermined range, and whose circularity is greater than a predetermined first threshold value, and whose circularity is greater than a predetermined second threshold value, and an output unit that outputs the diameter of the bright region extracted by the extraction processing unit as the particle size of the object corresponding to the bright region extracted by the extraction processing unit. The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The circularity is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times pi. Hereinafter, such a particle size measuring device, as well as the particle size measuring method and particle size measuring program implemented thereon, will be described by using, as an example, an example applied to the blast furnace erection process. However, the object is not limited to iron ore pellets, and may be any substance (for example, raw materials, products, etc.) as long as it is a deposited, spherical object.

[0030] FIG. 1 is a block diagram showing the configuration of the particle size measuring apparatus according to the embodiment. FIG. 2 is a diagram for explaining the arrangement of the imaging unit and the illumination unit in the particle size measuring apparatus. FIG. 3 is a diagram for explaining the shading correction executed by the particle size measuring apparatus. FIG. 4 is a diagram for explaining the dilation processing executed by the particle size measuring apparatus. FIG. 4A shows, as an example, a binarized image to be subjected to the dilation processing, and FIG. 4B shows an image of the processing result obtained by dilating the binarized image shown in FIG. 4A. FIG. 5 is a diagram showing, as an example, the processing result of performing the dilation processing twice. FIG. 5A shows, as an example, a binarized image to be subjected to the dilation processing, FIG. 5B shows an image of the processing result obtained by dilating the binarized image shown in FIG. 5A, and FIG. 5C shows an image of the processing result obtained by further dilating the image shown in FIG. 5B. The image shown in FIG. 5A is the same as the binarized image shown in FIG. 4A, and thus, the image shown in FIG. 5B is the same as the image shown in FIG. 4B. FIG. 6 is a diagram for explaining the ellipse approximation processing executed by the particle size measuring apparatus.

[0031] In the embodiment, the particle size measuring apparatus D includes, for example, as shown in FIGS. 1 and 2, an imaging unit 1, an illumination unit 2 (2-1, 2-2), a control processing unit 3, an input unit 4, an output unit 5, an interface unit (IF unit) 6, and a storage unit 7.

[0032] The imaging unit 1 is connected to the control processing unit 3 and is a device that captures a plurality of spherical objects deposited and generates an image according to the control of the control processing unit 3. The imaging unit 1 includes, for example, an imaging optical system that forms an optical image of an imaging target on a predetermined imaging surface, an area image sensor that is disposed with a light receiving surface coinciding with the imaging surface and converts the optical image of the imaging target into an electrical signal, and an image processing unit that generates image data representing an image of the imaging target by performing image processing on the output of the area image sensor. The imaging unit 1 may be a color digital camera, but in the present embodiment, since the luminance value of the image is binarized, it may be a monochrome digital camera as described later.

[0033] The lighting unit 2 is a device that is connected to the control processing unit 3 and illuminates the plurality of deposited spherical objects according to the control of the control processing unit 3. Note that the lighting unit 2 may be turned on and off manually without being connected to the control processing unit 3.

[0034] In the granulation process of a blast furnace, for example, granulators such as pan type or drum type are provided. The granulator is supplied with a granulation raw material in which auxiliary raw materials are blended into the raw powdered iron ore as necessary, for example, a binder such as quicklime or bentonite is blended, and a predetermined amount of moisture is further added. By rotating the granulator at a predetermined inclination angle and rotation speed, the granulation raw material is granulated into green pellets. The green pellets Ob discharged from the granulator are carried out by the carry-out conveyor BC, screened to a predetermined particle size range via a vibrating screen, and then conveyed to a firing furnace (sintering machine) such as a grate kiln for drying and firing.

[0035] In this embodiment, as an example, the particle size measuring device D is used in such a granulation process of a blast furnace. In order to measure the particle size of iron ore pellets in a substantially real-time manner, the imaging unit 1 is arranged to image, from above, a plurality of green pellets (an example of the plurality of spherical objects) Ob deposited and conveyed on the conveying conveyor BC. More specifically, as shown in FIG. 2, the optical axis thereof is arranged along the normal direction of the conveying surface in the conveying conveyor BC (the vertical direction of the paper surface in FIG. 2, the Z direction). The lighting unit 2 is arranged to illuminate the green pellets Ob obliquely from above. In the example shown in FIG. 2, the lighting unit 2 includes two first and second lighting units 2-1 and 2-2, and is juxtaposed through the imaging unit 1 along the conveying direction of the conveying conveyor BC (the depth direction of the paper surface in FIG. 2, the X direction) and the direction orthogonal to the normal direction of the conveying surface (the left-right direction of the paper surface in FIG. 2, the Y direction). In this way, by intentionally illuminating the green pellets Ob with such brightness that a change in luminance occurs according to the presence or absence of the green pellets Ob on the conveying conveyor BC by the pair of lighting units 2-1 and 2-2 on the left and right of the imaging unit 1, a change in luminance in the green pellets Ob to be measured can stably appear. And since sufficient illuminance is ensured even in the situation where the subject is being conveyed, that is, moving, a clear image can be generated by suppressing the exposure time during imaging. Therefore, since the particle size measuring device D can measure the particle size in such a constant lighting environment, the variation in measurement accuracy can be reduced. In addition, in order to prevent so-called stray light, a light shielding member (for example, a dark curtain, etc.) provided to cover the first and second lighting units 2-1 and 2-2 may be used to shield light from the outside.

[0036] The input unit 4 is connected to the control processing unit 3, and is a device that inputs various commands such as commands for instructing the start of particle size measurement and various data necessary for operating the particle size measuring device D, such as the date and time of measurement, into the particle size measuring device D. For example, it is a plurality of input switches, a keyboard, a mouse, etc. to which predetermined functions are assigned. The output unit 5 is connected to the control processing unit 3, and is a device that outputs commands and data input from the input unit 4 and the particle size obtained by the particle size measuring device D in accordance with the control of the control processing unit 3. For example, it is a display device such as a CRT display, an LCD (liquid crystal display device), and an organic EL display, or a printing device such as a printer.

[0037] Note that the input unit 4 and the output unit 5 may be constituted by a touch panel. When configuring this touch panel, the input unit 4 is a position input device that detects and inputs an operation position, such as a resistive film method or a capacitance method, and the output unit 5 is a display device. In this touch panel, the position input device is provided on the display surface of the display device, and one or a plurality of input content candidates that can be input to the display device are displayed. When the user touches the display position where the input content to be input is displayed, the position is detected by the position input device, and the display content displayed at the detected position is input to the particle size measuring device D as the user's operation input content. In such a touch panel, since the user can easily understand the input operation intuitively, a particle size measuring device D that is easy for the user to handle is provided.

[0038] The IF unit 6 is connected to the control processing unit 3, and is a circuit that inputs and outputs data to and from external devices, for example, in accordance with the control of the control processing unit 3. For example, it is an interface circuit of RS-232C using a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, and an interface circuit using the USB standard. Further, the IF unit 6 may be a communication interface circuit that transmits and receives communication signals to and from external devices, such as a data communication card or a communication interface circuit according to the IEEE802.11 standard.

[0039] The memory unit 7 is a circuit connected to the control processing unit 3 and stores various predetermined programs and various predetermined data according to the control of the control processing unit 3. The various predetermined programs include, for example, a control processing program. The control processing program includes, for example, a control program for controlling each part 1, 2, 4 to 7 of the particle size measuring device D according to the functions of the respective parts, a binarization processing program for binarizing the image generated by the imaging unit 1 based on the luminance value to generate a binarized image, an extraction processing program for extracting a bright region from one or more bright regions in the binarized image generated by the binarization processing program, where the diameter of the bright region based on the area is within a predetermined range, the circularity of the bright region is greater than a predetermined first threshold value, and the circularity of the bright region is greater than a predetermined second threshold value, a shading correction processing program for shading-correcting the image generated by the imaging unit 1 before binarizing with the binarization processing program, a smoothing processing program for smoothing the image generated by the imaging unit 1 before binarizing with the binarization processing program, a separation processing program for separating the bright region formed by connecting a plurality of spherical shapes into spherical bright regions before extracting with the extraction processing program, a dilation processing program for performing a dilation process of expanding the outer periphery of the bright region by a predetermined length in the radially outward direction one or more times before extracting with the extraction processing program, an ellipse approximation processing program for deforming the shape of the bright region into the most approximate elliptical shape before extracting with the extraction processing program, and the like. The various predetermined data include, for example, data necessary for executing these programs, such as the image captured by the imaging unit 1, the predetermined range (its lower limit value and upper limit value), the first threshold value, and the second threshold value. Such a memory unit 7 includes, for example, a ROM (Read Only Memory) which is a non-volatile memory element, an EEPROM (Electrically Erasable Programmable Read Only Memory) which is a rewritable non-volatile memory element, and the like. And the memory unit 7 includes a RAM (Random Access Memory) and the like which serve as a working memory of the so-called control processing unit 3 for storing data and the like generated during the execution of the predetermined program.Further, the storage unit 7 may be configured to include a hard disk drive with a relatively large storage capacity.

[0040] The control processing unit 3 is a circuit that controls each part 1, 2, 4 to 7 of the particle size measuring device D according to the functions of the respective parts, and obtains the particle size of a spherical object. The control processing unit 3 is configured to include, for example, a CPU (Central Processing Unit) and its peripheral circuits. When the control processing program is executed, the control processing unit 3 functionally includes a control unit 31, a shading correction processing unit 32, a smoothing processing unit 33, a binarization processing unit 34, a separation processing unit 35, a dilation processing unit 36, an ellipse approximation processing unit 37, and an extraction processing unit 38. Note that, as will be described later, the particle size of the spherical object is obtained in the extraction processing in which the extraction processing unit 38 recognizes and extracts the spherical object.

[0041] The control unit 31 controls each part 1, 2, 4 to 7 of the particle size measuring device D according to the functions of the respective parts, and is in charge of the overall control of the particle size measuring device D.

[0042] The binarization processing unit 34 binarizes the image generated by the imaging unit 1 based on the luminance value to generate a binarized image. The binarization processing unit 34 will be described later.

[0043] The extraction processing unit 38 extracts, from one or a plurality of bright regions in the binarized image generated by the binarization processing unit 34, a bright region whose diameter based on the area is within a predetermined range, and whose circularity is greater than a predetermined first threshold value, and whose circularity is greater than a predetermined second threshold value. The extraction processing unit 38 will be described later.

[0044] The shading correction processing unit 32 performs shading correction on the image generated by the imaging unit 1 before binarization by the binarization processing unit 34. The shading correction corrects uneven brightness caused by the optical system used when generating the image. In the present embodiment, for example, as shown in FIG. 3, the shading correction processing unit 32 subtracts a first smoothed image SP1 obtained by smoothing the input image IP1 from the input image IP1, and adds an average brightness image AP of the input image IP1 to the subtraction result, thereby generating a shading correction image CP obtained by shading-correcting the input image IP1. In the present embodiment, the input image IP1 is an image generated by the imaging unit 1.

[0045] The first smoothed image SP1 is generated, for example, by filtering the input image IP1 with an averaging filter of an image filter that simply averages. When the first smoothed image SP1 is generated by filtering with this averaging filter, assuming that the pixel position of the image to be processed is (x, y), the pixel value a'(x, y) after image processing is obtained by the following Equation 1.

[0046]

Equation

[0047] Alternatively, for example, the first smoothed image SP is generated by filtering the input image IP1 with a Gaussian filter of an image filter using a Gaussian function. The average brightness image AP is an image obtained by obtaining the average value of the brightness values of each pixel in the input image IP1 as the average brightness value and using this average brightness value as the pixel value of each pixel.

[0048] The smoothing processing unit 33 smooths the image generated by the imaging unit 1 before it is binarized by the binarization processing unit 34. In this embodiment, since the image generated by the imaging unit 1 is smoothed after shading correction, the smoothing processing unit 33 uses a smoothing filter of an image filter that smoothes the luminance values of the shading-corrected image obtained by the shading correction processing unit 32 to generate a second smoothed image obtained by smoothing the shading-corrected image. An averaging filter or a Gaussian filter is used as the smoothing filter.

[0049] The binarization processing unit 34 binarizes the second smoothed image smoothed by the smoothing processing unit 33 based on the luminance value, and generates a binarized image obtained by binarizing the second smoothed image. For this binarization, for example, the so-called Otsu's binarization processing is used. This Otsu's binarization processing obtains the histogram of the image to be binarized (input image, here the second smoothed image), defines the ratio of the variance of one side to the variance between the two when the histogram is divided into two as the separation degree, and binarizes using the class of the histogram at the position where the separation degree is maximized as the threshold value.

[0050] The separation processing unit 35 separates (contour separation) the bright region formed by connecting a plurality of spherical shapes into spherical bright regions before extraction by the extraction processing unit 38. In this embodiment, the separation processing unit 35 separates the bright region formed by connecting a plurality of spherical shapes into spherical bright regions by using, for example, the so-called Watershed method on the binarized image binarized by the binarization processing unit 34. This Watershed method is a technique that regards the target image (input image, here the binarized image) as a topographical structure and performs region division of the image by simulating the state transition when water is filled in the topographical structure in order from the low places.

[0051] The separation processing unit 35 performs a labeling process of sequentially assigning integer serial numbers from 1 to each of the separated bright regions in order to identify and distinguish each of the separated bright regions. Each number assigned to each bright region in this labeling process serves as an identifier (ID, serial number) for identifying and distinguishing the bright region.

[0052] The dilation processing unit 36 performs a dilation process of expanding the outer periphery of the bright region by a predetermined length in the radially outward direction one or more times before extraction by the extraction processing unit 38. In this embodiment, this dilation process is performed for each bright region separated by the separation processing unit 35 and assigned a serial number. More specifically, for example, for each pixel belonging to the bright region, the dilation processing unit 36 sets each of the pixels located before, after, to the left, and to the right of the pixel as a bright region. That is, the pixel value 0 representing black is changed to the pixel value 1 representing white and becomes a bright region. In other words, for each pixel located on the outer periphery of the bright region, one pixel located outside the pixel in the front-back direction (vertical direction) of the pixel is set as a bright region, and one pixel located outside the pixel in the left-right direction (horizontal direction) of the pixel is set as a bright region. In one example, when the dilation process is performed on the first pixel PX1 belonging to the first bright region LA1 in the input image IP2 shown in FIG. 4A, as shown in FIG. 4B, each of the pixels located before, after, to the left, and to the right of the first pixel PX1 has its pixel value changed from 0 to 1 and becomes a bright region. As a result, in the input image IP2, the first bright region LA1 was a region consisting of one first pixel PX1, but due to the dilation process, it expands to a region ELA1 consisting of five pixels. Similarly, the second bright region LA2 in the input image IP2 shown in FIG. 4A was a region consisting of eight pixels PX21 to PX28, but due to the dilation process, as shown in FIG. 4B, it expands to a region ELA2 consisting of 19 pixels. When the dilation process is further performed on the image after one dilation process shown in FIG. 4B, the image shown in FIG. 5C (the image after two dilation processes) is obtained. The image shown in FIG. 5A is the same as the image shown in FIG. 4A, and the image shown in FIG. 5B is the same as the image shown in FIG. 4B. Note that in this example, the predetermined length was the length of one pixel, but it is not limited to this, and it may be appropriately set in consideration of the difference between the size of the image of the object shown in the image and the actual size. Also, in this example, the dilation process was performed twice, but it is not limited to this, and it may be appropriately set in consideration of the difference between the size of the image of the object shown in the image and the actual size.

[0053] Note that, as shown in FIG. 5C, although overlapping pixels occur between the first bright region LA1 and the second bright region LA2 due to the dilation process, the first bright region LA1 and the second bright region LA2 are distinguished by serial numbers and are individually dilated as described above. Therefore, as a result of the dilation process, they only appear to overlap and do not merge into one.

[0054] The ellipse approximation processing unit 37 deforms the shape of the bright region into an ellipse shape that most closely approximates it before extraction by the extraction processing unit 38. In the present embodiment, the ellipse approximation processing unit 37 is performed for each bright region dilated by the dilation processing unit 36. More specifically, for example, as shown in FIG. 6, the ellipse approximation processing unit 37 first obtains the distance from each pixel PXi belonging to the bright region LA3 to the ellipse EL of the pixel PXi. Next, the ellipse approximation processing unit 37 obtains the sum of these obtained distances for each pixel PXi belonging to the bright region LA3 as the error function δ. Then, the ellipse approximation processing unit 37 solves the ellipse EL for which the obtained error function δ is minimized, for example, by least squares estimation. Thereby, the ellipse EL that most closely approximates the bright region AL3 is obtained.

[0055] The extraction processing unit 38 extracts, from among the bright regions deformed into an ellipse shape by the ellipse approximation processing unit 37, the bright regions whose diameter based on the area of the bright region is within a predetermined range, and whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value. The diameter R of the bright region based on the area S is obtained as the particle diameter R of the spherical object by doubling the square root of the division result obtained by dividing the area S by the pi (R = 2 × √(S / π)). 1 / 2)。Since the bright region is deformed (approximated) into an elliptical shape, the area S is obtained by the formula for calculating the area of an ellipse (S = π × a × b, where a is the major axis length and b is the minor axis length). Alternatively, the area S may be obtained by determining the number of pixels belonging to the bright region before deformation into the elliptical shape. The circularity TC is the reciprocal of the aspect ratio (= b / a), which is the ratio of the major axis length b to the minor axis length a when the contour of the bright region is approximated by an ellipse (TC = a / b). The circularity CD is the result of multiplying the division result obtained by dividing the area S of the bright region by the square of the perimeter length l of the bright region by 4 times pi (CD = 4 × π × S / l 2 )。

[0056] More specifically, first, the extraction processing unit 38 selects one bright region from among the bright regions deformed into an elliptical shape by the elliptical approximation processing unit 37. Next, the extraction processing unit 38 obtains the diameter R in the selected bright region. Next, the extraction processing unit 38 obtains the circularity TC and the circularity CD in the selected bright region, respectively. Then, the extraction processing unit 38 determines whether or not the selected bright region satisfies the determination condition for determining whether or not the bright region is a particle. The determination condition is that the diameter R of the bright region based on the area S is within a predetermined range (Thd < R < Thu, Thd: the lower limit value of the predetermined range, Thu: the upper limit value of the predetermined range), and the circularity TC of the bright region is greater than a predetermined first threshold Th1 (TC > Th), and the circularity CD of the bright region is greater than a predetermined second threshold Th2 (CD > Th2). As a result of the determination, when Thd < R < Thu, and TC > Th, and CD > Th2, the extraction processing unit 38 determines that the selected bright region is a particle, and extracts the selected bright region as the spherical object. On the other hand, as a result of the determination, when at least one of Thd < R < Thu, TC > Th, and CD > Th2 does not hold, the extraction processing unit 38 determines that the selected bright region is not a particle, and does not extract the selected bright region as the spherical object. The extraction processing unit 38 performs such processing for each of the bright regions deformed into an elliptical shape by the elliptical approximation processing unit 37. The upper limit value Thd, the lower limit value Thu, the first threshold Th1, and the second threshold Th2 are appropriately set in advance from, for example, a plurality of samples.

[0057] The control unit 31 outputs, from the output unit 5, the diameter R of the bright region extracted by the extraction processing unit 38 as the particle size of the object corresponding to the bright region extracted by the extraction processing unit 38.

[0058] These control processing unit 3, input unit 4, output unit 5, F unit 6, and storage unit 7 can be configured by, for example, a computer such as a desktop type or a notebook type. The computers constituting these units 3 to 7 can be arranged, for example, in an operation room in a granulation process plant, incorporated in a console (may be used in combination with the console), or may be separate from the console.

[0059] Next, the operation of this embodiment will be described. FIG. 7 is a flowchart showing the operation of the particle size measuring device. FIG. 8 is a diagram for explaining the result when only binarization processing and extraction processing are performed. FIG. 9 is a diagram for explaining the result when only binarization processing, dilation processing, and extraction processing are performed. FIG. 10 is a diagram for explaining the result when only binarization processing, dilation processing, ellipse approximation processing, and extraction processing are performed. FIG. 11 is a diagram showing the correlation between the particle size obtained by the particle size measuring device and the actually measured particle size. The horizontal axis in FIG. 11 is the particle size obtained by the particle size measuring device D, and the vertical axis is the particle size actually measured by a sieve. FIG. 12 is a diagram for explaining an example.

[0060] When the power of the particle size measuring device D having such a configuration is turned on, it initializes each necessary unit and starts its operation. In the control processing unit 3, a control unit 31, a shading correction processing unit 32, a smoothing processing unit 33, a binarization processing unit 34, a separation processing unit 35, a dilation processing unit 36, an ellipse approximation processing unit 37, and an extraction processing unit 38 are functionally configured by executing its control processing program.

[0061] During granulation, the particle size measuring device D repeatedly executes each process shown in FIG. 7 at a preset predetermined time interval (for example, an appropriate interval such as 5 seconds, 10 seconds, 30 seconds, 60 seconds, or 5 minutes), and measures the particle size of the raw pellets Ob substantially in real time.

[0062] In FIG. 7, the particle size measuring device D acquires an image by the imaging unit 1 under the control of the control unit 31 of the control processing unit 3 and stores it in the storage unit 7 (S1).

[0063] Subsequently, the particle size measuring device D performs shading correction on the image acquired from the imaging unit 1 in process S1 by the shading correction unit 32 of the control processing unit 3 to generate a shading-corrected image, and stores it in the storage unit 7 (S2).

[0064] Subsequently, the particle size measuring device D smooths the shading-corrected image generated by the shading correction unit 32 in process S2 by the smoothing unit 33 of the control processing unit 3 to generate a second smoothed image, and stores it in the storage unit 7 (S3).

[0065] Subsequently, the particle size measuring device D binarizes the second smoothed image generated by the smoothing unit 33 in process S3 by the binarization unit 34 of the control processing unit 3 to generate a binarized image, and stores it in the storage unit 7 (S4).

[0066] Subsequently, the particle size measuring device D performs a separation process on the binarized image generated by the binarization unit 34 in process S4 by the separation unit 35 of the control processing unit 3, separating the bright region formed by the connection of a plurality of spherical shapes into spherical bright regions, to generate a binarized image after the separation process, and stores it in the storage unit 7 (S5).

[0067] Subsequently, the particle size measuring device D performs a labeling process on the binarized image after the separation process separated in process S5 by the separation unit 35 of the control processing unit 3, sequentially assigning serial numbers from 1 to each of the separated bright regions (S6).

[0068] Subsequently, the particle size measuring device D selects one bright region from among the bright regions in the binarized image after the separation process generated by the separation unit 35 in process S5 by the dilation unit 36 of the control processing unit 3, performs a dilation process on the selected bright region, and stores the binarized image after the dilation process of the selected bright region in the storage unit 7 (S7). At this time, the dilation unit 36 associates the fact that the selected bright region has been selected. For example, a flag indicating whether it has been selected (selection status flag, where "1" indicates selected and "0" indicates unselected) is associated with the serial number of the selected bright region.

[0069] Subsequently, the particle size measuring device D performs an ellipse approximation process in which the shape of the bright region selected in the process S7 is deformed into an ellipse shape that most approximates the shape by the ellipse approximation unit 37 of the control processing unit 3, and stores in the storage unit 7 a binarized image of the selected bright region after the ellipse approximation process (S8).

[0070] Subsequently, the particle size measuring device D performs an extraction process in which the extraction processing unit 38 of the control processing unit 3 determines whether or not the selected bright region satisfies the determination condition, and extracts the bright region that satisfies the determination condition (S9). More specifically, as described above, the extraction processing unit 38 obtains the diameter R in the selected bright region, obtains the circularity TC and the circularity CD respectively, and determines whether or not the selected bright region satisfies the determination condition. As a result of this determination, when Thd < R < Thu, and TC > Th, and CD > Th2, the extraction processing unit 38 determines that the selected bright region is a particle, extracts the selected bright region as the spherical object, and stores it in the storage unit together with its particle size R. For example, a flag indicating whether or not it has been recognized as a particle (particle recognition flag, "1" indicates particle recognition, "0" indicates non-particle recognition) is associated with the serial number of the selected bright region together with its particle size R. On the other hand, as a result of the determination, when at least one of Thd < R < Thu, TC > Th, and CD > Th2 does not hold, the extraction processing unit 38 determines that the selected bright region is not a particle and does not extract the selected bright region as the spherical object.

[0071] Subsequently, the particle size measuring device D determines, by the extraction processing unit 38, whether or not each of these processes from process S7 to process S9 has been completed for all bright regions, that is, all bright regions assigned with serial numbers in process S6 (S10). As a result of this determination, if each process has been completed for all bright regions (YES), the particle size measuring device D then executes process S11. On the other hand, as a result of the determination, if each process has not been completed for all bright regions (NO), the particle size measuring device D returns the process to process S7. Therefore, each of these processes from process S7 to process S9 is performed for all bright regions assigned with serial numbers in process S6. For example, in the selection of bright regions in process S7, bright regions are sequentially selected in serial number order, and for each bright region assigned with a serial number in process S6, each of these processes from process S7 to process S9 is sequentially performed in serial number order.

[0072] In this process S11, the particle size measuring device D outputs, by the control unit 31, the diameter R of the bright region extracted by the extraction processing unit 38 from the output unit 5 as the particle size of the object corresponding to the bright region extracted by the extraction processing unit 38, and ends this process. In this output, for example, the particle sizes are classified into a plurality of classes, and different display modes are assigned to each of the plurality of classes. The binarized image after the dilation process and the ellipse approximation process is displayed on the output unit 5 with each bright region displayed in a display mode corresponding to the class to which the particle size R of the bright region belongs. For example, the particle sizes are classified into a first class of 2 mm or less, a second class of more than 2 mm and 2.8 mm or less, and a third class of more than 2.8 mm. Red is assigned as the display mode to the first class, green is assigned as the display mode to the second class, and yellow is assigned as the display mode to the third class.

[0073] Note that, if necessary, the measurement result of the particle size may be output from the IF unit 6 to an external device.

[0074] By operating in this manner, the particle size measuring device D determines the particle size of the particles identified as such based on the images of the plurality of deposited spherical objects captured by the imaging unit 1.

[0075] Here, in FIG. 7, the particle size measuring device D performs shading correction processing, smoothing processing, binarization processing, separation processing, dilation processing, ellipse approximation processing, and extraction processing when measuring the particle size. However, the shading correction processing, the smoothing processing, the separation processing, the dilation processing, and the ellipse approximation processing are more preferably processing for measuring the particle size, and it is not necessarily required to perform them. Some or all of these processes may be streamlined. That is, the particle size measuring device D may be configured to include, as a basic form, an imaging unit 1, a binarization processing unit 34 that performs the binarization processing, an extraction processing unit 38 that performs the extraction processing, and an output unit 5. To this basic form of the particle size measuring device D, some or all of the shading correction processing, the smoothing processing, the separation processing, the dilation processing, and the ellipse approximation processing may be added as necessary.

[0076] FIG. 8 shows an example of the result by the particle size measuring device D in the basic form. That is, in FIG. 8, an image is acquired by the imaging unit 1, the acquired image is binarized to generate a binarized image, serial numbers are assigned to each bright region of the binarized image, and the result when extraction processing is performed on each bright region of the binarized image is shown as an example. FIG. 8A shows the image acquired by the imaging unit 1, and FIG. 8B shows the image of the result of the extraction processing for the image shown in FIG. 8A. As can be seen by comparing the image shown in FIG. 8A with the image shown in FIG. 8B, the object exposed on the uppermost layer among the plurality of deposited spherical objects is preferentially extracted. Although not shown, the particle size of the object obtained by a sieve and the particle size of the object obtained by the particle size measuring device D as described above were correlated with a correlation coefficient R 2 = 0.7957 in this specific example.

[0077] FIG. 9 shows an example of the result when the expansion process is added to the particle size measuring device D in the basic form. That is, in FIG. 9, an image is acquired by the imaging unit 1, the acquired image is binarized to generate a binarized image, a serial number is assigned to each bright region of the binarized image, and for each bright region of the binarized image, after the expansion process is performed, the result when the extraction process is performed is shown as an example. FIG. 9A shows the image acquired by the imaging unit 1, and FIG. 9B shows the image of the result of the extraction process for the image shown in FIG. 9A. As can be seen by comparing the image shown in FIG. 9A with the image shown in FIG. 9B, the object exposed on the uppermost layer among the plurality of spherical objects deposited is preferentially extracted. Although not shown, the particle size of the object obtained by the sieve and the particle size of the object obtained by the particle size measuring device D as described above were more correlated with a correlation coefficient R 2 = 0.8037. It can be inferred that due to the expansion process, particles that were smaller than the actual size and appeared in the image in relation to the illumination became closer to the actual size due to the expansion process.

[0078] FIG. 10 shows an example of the result when the expansion process and the ellipse approximation process are added to the particle size measuring device D of the basic form. That is, in FIG. 10, an image is acquired by the imaging unit 1, the acquired image is binarized to generate a binarized image, a serial number is assigned to each bright region of the binarized image, and for each bright region of the binarized image, after each of the expansion process and the ellipse approximation process is performed, an example of the result when an extraction process is performed is shown. FIG. 10A shows the image acquired by the imaging unit 1, and FIG. 10B shows the image of the result of the extraction process for the image shown in FIG. 10A. FIGS. 8B and 9B show binarized images, but in FIG. 10B, since it is difficult to see connected particles or overlapping particles when shown as a binarized image, a grayscale image is shown. As can be seen by comparing the image shown in FIG. 10A and the image shown in FIG. 10B, the object exposed on the uppermost layer among the plurality of spherical objects deposited is preferentially extracted. Although not shown, the particle size of the object obtained by the sieve and the particle size of the object obtained by the particle size measuring device D as described above are, in this specific example, the correlation coefficient R 2 = 0.8103, and they were even more correlated. And when the number of measurements is further increased in this specific example, as shown in FIG. 11, the particle size (vertical axis) of the object obtained by the sieve and the particle size (horizontal axis) of the object obtained by the particle size measuring device D as described above are correlated with a correlation coefficient R 2 = 0.8664. The average particle size in FIG. 11 is the average value of the particle sizes of all particles.

[0079] FIG. 12 shows an example of the results of measuring a plurality of as-deposited green pellets Ob carried on the unloading conveyor BC during granulation using the particle size measuring device D in the embodiment. FIG. 12A shows the actual measurement results of the average particle size during granulation, FIG. 12B shows each image and its extraction results at time t1 shown in FIG. 12A, FIG. 12C shows each image and its extraction results at time t2 shown in FIG. 12A, and FIG. 12D shows each image and its extraction results at time t3 shown in FIG. 12A. In FIGS. 12B to 12D, the upper part shows the images generated by the imaging unit 1, and the lower part shows the extraction results. The measurement result of #1 shown in FIG. 12A is the measurement result in the first region from the left side of the paper in the plan view shown in each of FIGS. 12B to 12D, the measurement result of #2 shown in FIG. 12A is the measurement result in the second region from the left side of the paper in the plan view shown in each of FIGS. 12B to 12D, the measurement result of #3 shown in FIG. 12A is the measurement result in the third region from the left side of the paper in the plan view shown in each of FIGS. 12B to 12D, and the measurement result of #4 shown in FIG. 12A is the measurement result in the fourth region from the left side of the paper in the plan view shown in each of FIGS. 12B to 12D.

[0080] As can be seen from FIG. 12A, at time t2, the average particle size of the measurement results in the fourth region from the left side of the paper in the plan view is larger compared to other regions. Referring to the image shown in the upper part of FIG. 12C, it can be confirmed that the particles in the fourth region are larger than those in other regions (the first to third regions). Therefore, the particle size measuring device D in the present embodiment can quantitatively and continuously measure the particle size.

[0081] As described above, the particle size measuring device D in the embodiment, as well as the particle size measuring method and the particle size measuring program implemented thereon, measure the particle size of the objects based on an image of a plurality of deposited spherical objects, so there is no need to extract the objects as in the sieve test. The above particle size measuring device D, particle size measuring method and particle size measuring program extract a bright region whose diameter based on area is within a predetermined range, and whose circularity is greater than a predetermined first threshold value and whose circularity is greater than a predetermined second threshold value. Therefore, when a plurality of the objects are deposited, only the objects exposed on the upper part can be recognized and the particle size can be measured.

[0082] Since the above particle size measuring device D, particle size measuring method and particle size measuring program illuminate, the particle size can be measured under a certain illumination environment. Therefore, not only for a stationary subject, but also when the subject is being conveyed or moving, sufficient illuminance is ensured. By suppressing the exposure time during imaging (that is, by increasing the shutter speed), a clear image can be generated and the variation in measurement accuracy can be reduced.

[0083] Since the above particle size measuring device D, particle size measuring method and particle size measuring program perform shading correction processing, even when there is spatial illuminance unevenness, the illuminance unevenness can be reduced and the particle size can be measured more accurately.

[0084] Since the above particle size measuring device D, particle size measuring method and particle size measuring program perform smoothing processing, the luminance difference caused by the shape of the object surface, attachments, etc. can be reduced and the particle size can be measured more accurately.

[0085] Since the above particle size measuring device D, particle size measuring method and particle size measuring program perform separation processing, even if a plurality of spherical shapes are connected, they can be separated and the particle size can be measured more accurately.

[0086] Since the particle size measuring device D, the particle size measuring method, and the particle size measuring program perform dilation processing, when the outer peripheral portion of an object is darkly imaged, the measurement result will be smaller than the actual size. However, even in such a case, since the outer periphery of the bright region is dilated, the particle size can be measured closer to the actual size.

[0087] Since the particle size measuring device D, the particle size measuring method, and the particle size measuring program perform ellipse approximation processing, for a plurality of deposited spherical objects that slightly overlap and whose shape is difficult to see, the shape can be restored by ellipse approximation, and the number of measurable objects can be increased.

[0088] In the above-described embodiment, the particle size measuring device D includes the imaging unit 1 that generates an image of the green pellet Ob in order to measure the particle size of the iron ore pellet in substantially real time. However, in order to verify the past granulation process, instead of the imaging unit 1 or in addition to the imaging unit 1, the particle size measuring device D may include an image acquisition unit that acquires an image of a plurality of deposited spherical objects. Such a particle size measuring device D basically includes the image acquisition unit, the binarization processing unit, the extraction processing unit, and the output unit. These binarization processing unit, extraction processing unit, and output unit are the same as the binarization processing unit 34, extraction processing unit 38, and output unit 5 described above, respectively.

[0089] The image acquisition unit is an interface circuit for inputting and outputting data to and from an external device. The external device is a storage medium such as a USB (Universal Serial Bus) memory and an SD card (registered trademark) that stores an image of a plurality of spherical objects deposited thereon. Alternatively, the external device is a drive device that reads data from a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a CD-R (Compact Disc Recordable), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a DVD-R (Digital Versatile Disc Recordable) that records the image. The interface circuit as the image acquisition unit may be connected to the external device by wire or wirelessly. Alternatively, the image acquisition unit is, for example, a communication interface circuit that transmits and receives communication signals to and from an external device, and the external device is connected to the communication interface circuit via a network (WAN (Wide Area Network, including a public communication network)) or a LAN (Local Area Network), and is a server device that manages the image. Such an image acquisition unit may be used in combination with the IF unit 6 (that is, the IF unit 6 may be used as the image acquisition unit).

[0090] In order to represent the present invention, the present invention has been appropriately and sufficiently described through embodiments with reference to the drawings above. However, it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, as long as the changes or improvements made by those skilled in the art do not depart from the scope of the claims described in the claims, the changes or improvements are construed to be included in the scope of the claims of the claims.

Description of Reference Numerals

[0091] D Particle size measuring device 1 Imaging unit 2 Lighting unit 3 Control Processing Unit 4 Input Unit 5 Output Unit 6 Interface Unit (IF Unit) 7 Memory Unit 31 Control Unit 32 Shading Correction Processing Unit 33 Smoothing Processing Unit 34 Binarization Processing Unit 35 Separation Processing Unit 36 Dilation Processing Unit 37 Ellipse Approximation Processing Unit 38 Extraction Processing Unit

Claims

1. An imaging unit that images a plurality of stacked spherical objects to generate an image; A binarization processing unit that binarizes the image generated by the imaging unit based on luminance values to generate a binarized image; An extraction processing unit that extracts, from one or more bright regions in the binarized image generated by the binarization processing unit, a bright region whose diameter based on the area is within a predetermined range, whose roundness is greater than a predetermined first threshold value, and whose circularity is greater than a predetermined second threshold value; An output unit that outputs the diameter of the bright region extracted by the extraction processing unit as the particle size of the object corresponding to the bright region extracted by the extraction processing unit, and The roundness is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse, The circularity is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times pi. A particle size measuring device.

2. Further comprising an illumination unit that illuminates the plurality of objects, The particle size measuring device according to claim 1.

3. Further comprising a shading correction processing unit that performs shading correction on the image generated by the imaging unit before binarization by the binarization processing unit, The particle size measuring device according to claim 1 or claim 2.

4. Further comprising a smoothing processing unit that smooths the image generated by the imaging unit before binarization by the binarization processing unit, The particle size measuring device according to claim 1 or claim 2.

5. Further comprising a separation processing unit that separates the bright region formed by connecting a plurality of spherical shapes into spherical bright regions before extraction by the extraction processing unit, The particle size measuring device according to any one of claims 1 to 4.

6. Further comprising a dilation processing unit that performs a dilation process of expanding the outer periphery of the bright region by a predetermined length in the radially outward direction one or more times before extraction by the extraction processing unit, The particle size measuring device according to any one of claims 1 to 4.

7. Further comprising an ellipse approximation processing unit that deforms the shape of the bright region into the most approximate ellipse shape before extraction by the extraction processing unit, The particle size measuring device according to any one of claims 1 to 4.

8. An image acquisition unit that acquires an image of a plurality of stacked spherical objects; A binarization processing unit that binarizes the image acquired by the image acquisition unit based on luminance values to generate a binarized image, An extraction processing unit that extracts, from one or more bright regions in the binarized image generated by the binarization processing unit, a bright region whose diameter based on the area is within a predetermined range, whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value; An output unit that outputs the diameter of the bright region extracted by the extraction processing unit as the particle size of an object corresponding to the bright region extracted by the extraction processing unit; The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse; The roundness is a multiplication result obtained by multiplying a division result obtained by dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times pi; Particle size measuring device. **Claim 9** An imaging step of imaging a plurality of spherical objects deposited to generate an image; A binarization processing step of binarizing the image generated in the imaging step based on the luminance value to generate a binarized image; An extraction processing step of extracting, from one or more bright regions in the binarized image generated in the binarization processing step, a bright region whose diameter based on the area is within a predetermined range, whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value; An output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of an object corresponding to the bright region extracted in the extraction processing step; The circularity is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse; The roundness is a multiplication result obtained by multiplying a division result obtained by dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times pi; Particle size measuring method. **Claim 10** An image acquisition step of acquiring an image obtained by imaging a plurality of spherical objects deposited; A binarization processing step of binarizing the image acquired in the image acquisition step based on the luminance value to generate a binarized image; An extraction processing step of extracting, from one or more bright regions in the binarized image generated in the binarization processing step, a bright region whose diameter based on the area is within a predetermined range, whose circularity is greater than a predetermined first threshold value, and whose roundness is greater than a predetermined second threshold value; An output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of the object corresponding to the bright region extracted in the extraction processing step. The roundness is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The circularity is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times the pi. A particle size measurement method executed by a computer.

11. An image acquisition step of acquiring an image of a plurality of spherical objects deposited, A binarization processing step of binarizing the image acquired in the image acquisition step based on the luminance value to generate a binarized image, An extraction processing step of extracting a bright region from one or more bright regions in the binarized image generated in the binarization processing step, wherein the diameter of the bright region based on the area is within a predetermined range, and the roundness of the bright region is greater than a predetermined first threshold value, and the circularity of the bright region is greater than a predetermined second threshold value, An output step of outputting the diameter of the bright region extracted in the extraction processing step as the particle size of the object corresponding to the bright region extracted in the extraction processing step. The roundness is the reciprocal of the aspect ratio, which is the ratio of the major axis length to the minor axis length when the contour of the bright region is approximated by an ellipse. The circularity is the multiplication result obtained by multiplying the division result of dividing the area of the bright region by the square of the perimeter length of the bright region by 4 times the pi. A particle size measurement program executed by a computer.

Images