Molten metal occupancy rate measuring device and method

Abstract

To provide a molten metal occupancy measurement device which is capable of obtaining the occupancy of an image region with molten metal imprinted at more high precision, and a method therefor.SOLUTION: A molten metal occupancy measurement device D comprises an imaging unit 1 of creating a color image looked down at the inside of a container of molten metal, a first region extraction unit 24 of obtaining a slag image region of slag and a molten metal candidate image region which is a candidate for the molten metal based on a green image of a green component in the color image, a second region extraction unit 25 of obtaining the molten metal image region of at least one of the slag and the molten metal in the slag image region and the molten metal candidate image region obtained at the first region extraction unit 24 based on a red image of a red component in the color image and an occupancy treatment unit 26 of obtaining the occupancy of the image region with the molten metal imprinted as a naked molten metal area ratio based on the obtained slag molten metal image region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a molten metal occupancy rate measuring device and a molten metal occupancy rate measuring method for determining the occupancy rate of molten metal in a vessel containing the molten metal. [Background technology]

[0002] Slag floats on the surface of molten metal, such as molten pig iron removed from a blast furnace into a ladle or molten steel removed from a converter into a ladle. This slag is removed because it affects the quality and yield of the product. To remove this slag, it is necessary to determine whether it is molten metal or slag. For example, an operator (worker) refers to a sample of slag and removes any that are determined to be slag. In this case, the subjective judgment of each operator can vary, which may result in inappropriate removal of the slag. Therefore, an objective method for determining slag is desired, and a technique such as that disclosed in Patent Document 1 is available.

[0003] The slag quantification method disclosed in Patent Document 1 includes a brightness value calculation step of capturing an image of the surface of molten metal contained in a vessel using an imaging device and determining the brightness value of each pixel region of the captured image through image processing; a slag surface temperature calculation step of determining the relationship between brightness values ​​and radiance in advance and determining the surface temperature of the slag in each pixel region using the brightness values ​​determined in the brightness value calculation step based on this relationship and a temperature conversion equation; a slag thickness calculation step of estimating the slag thickness for each pixel region using the slag surface temperature determined in the slag surface temperature calculation step and a heat conduction equation; and a slag calculation step of determining the slag volume or total weight in the vessel based on the molten metal surface area per pixel region and the physical properties of the slag. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-112429 Summary of the Invention [Problem to be solved by the invention]

[0005] The slag quantification method disclosed in Patent Document 1 calculates the slag volume or total slag weight in a vessel by estimating the slag thickness for each pixel based on the relationship between the brightness and radiance values ​​previously determined and the slag surface temperature calculated from a temperature conversion equation. However, there is room for improvement in accuracy. In particular, when so-called thin slag occurs, the slag quantification method disclosed in Patent Document 1 has difficulty detecting the thin slag, potentially resulting in a decrease in accuracy. Conventional slag is composed primarily of high-temperature molten oxides such as silicon dioxide (SiO), aluminum oxide (alumina, AlO), and calcium oxide (CaO), as well as graphite precipitated from the molten iron. Its black color is formed from a viscous liquid phase and powder. On the other hand, thin slag has significantly less graphite than conventional slag, and its liquid phase is lighter in color, appearing similar to the color of molten iron at the surface. For this reason, it is more difficult to distinguish thin slag from molten iron than normal slag, making it difficult to detect thin slag.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a molten metal occupancy rate measuring device and a molten metal occupancy rate measuring method that can more accurately determine the occupancy rate of an image area that includes molten metal, rather than slag. [Means for solving the problem]

[0007] After extensive investigation, the inventors have found that the above object can be achieved by the present invention, which includes the following: an imaging unit that generates a color image of the interior of a vessel containing molten metal, a first region extraction unit that determines, based on a green image of a green component in the color image generated by the imaging unit, a slag image region determined to be an image region containing slag and a molten metal candidate image region determined to be a candidate image region containing the molten metal, a second region extraction unit that determines, based on a red image of a red component in the color image generated by the imaging unit, a slag molten metal image region determined to be an image region containing at least one of the slag and the molten metal from the slag image region and the molten metal candidate image region determined by the first region extraction unit, and a region ratio processing unit that calculates, as a bare metal area ratio, the region ratio of the image region containing the molten metal based on the slag image region and the molten metal candidate image region determined by the first region extraction unit and the slag molten metal image region determined by the second region extraction unit. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the occupancy rate processing unit determines a residual image area by excluding the slag molten metal image area determined by the second area extraction unit from the slag image area and molten metal candidate image area determined by the first area extraction unit, determines the image area by excluding the residual image area from the molten metal candidate image area determined by the first area extraction unit as the molten metal image area, and determines the occupancy rate of the determined molten metal image area as the bare metal area rate.

[0008] The inventors studied a color image of the interior of a vessel containing molten metal and found that more accurate determination of the molten metal area could be achieved by dividing the color image into color components rather than by the color image itself. Based on this finding, the molten metal area ratio measuring device calculates the area ratio of the image area containing the molten metal as the bare metal area ratio, thereby enabling more accurate determination of the area ratio of the image area containing molten metal, rather than slag. In other words, the molten metal area ratio measuring device can more accurately detect the image area containing slag (including normal slag and thin slag).

[0009] In another aspect, the above-mentioned molten metal occupancy rate measuring device further includes an operation execution determination unit that determines whether or not to obtain the bare molten metal area rate based on the brightness value within a predetermined execution determination image area in the color image generated by the imaging unit.

[0010] The bare molten metal area ratio is determined primarily to properly remove slag, and therefore only needs to be determined during the slag removal operation, but does not need to be determined when the slag removal operation is not in progress. The slag removal operation is often performed by tilting a vessel containing molten metal. If the imaging unit is fixedly disposed relative to the vessel, tilting the vessel changes the position of the image area capturing the interior of the vessel in the color image generated by the imaging unit, thereby changing the brightness value of a predetermined image area (the execution determination image area). The molten metal occupancy ratio measuring device further includes a calculation execution determination unit, which can determine whether the slag removal operation is in progress and can determine the bare molten metal area ratio only during the slag removal operation.

[0011] In another aspect, the above-described molten metal occupancy rate measuring device further includes: the first region extraction unit determines the slag image region and the molten metal candidate image region within a predetermined extracted image region in the color image; the second region extraction unit determines the molten metal slag image region within the extracted image region in the color image; and a region adjustment unit adjusts the extracted image regions used by the first and second region extraction units based on the color image generated by the imaging unit. Preferably, in the above-described molten metal occupancy rate measuring device, the extracted image region is represented by a mask image that masks an image; the first region extraction unit extracts the extracted image region by masking the color image or a green image of a green component in the color image with the mask image, and determines the slag image region and the molten metal candidate image region within the extracted extracted image region; and the second region extraction unit extracts the extracted image region by masking the color image or a red image of a red component in the color image with the mask image, and determines the molten metal slag image region within the extracted extracted image region. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the region adjustment unit selects one extraction image area from a plurality of different extraction image areas as the extraction image area to be used by each of the first and second region extraction units, based on the color image generated by the imaging unit. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the imaging unit is arranged so that its optical axis is fixed, the extraction image area is an internal image area that captures the internal area of ​​the container as viewed from above by the imaging unit and is represented by a mask image that masks the image, the plurality of extraction image areas are represented by a plurality of mask images corresponding to each of a plurality of tilt angles of the container, and the region adjustment unit selects, from a plurality of mask images corresponding to each of the plurality of extraction image areas, a mask image that best matches the internal image area that captures the internal area of ​​the container in the color image generated by the imaging unit, as the mask image for the extraction image area to be used by each of the first and second region extraction units.

[0012] The slag removal operation is not always performed with the container tilted at a fixed angle. The molten metal occupancy rate measuring device further includes an area adjustment unit, which makes it possible to adjust the extracted image area according to the actual angle at which the container is tilted, thereby more accurately determining the occupancy rate of the image area that includes molten metal, rather than slag.

[0013] A molten metal occupancy rate measurement method according to another aspect of the present invention includes an imaging step of generating a color image of an overhead view of the inside of a vessel containing molten metal; a first region extraction step of determining, based on a green image of a green component in the color image generated in the imaging step, a slag image region determined to be an image region containing slag and a molten metal candidate image region determined to be a candidate image region containing the molten metal; a second region extraction step of determining, based on a red image of a red component in the color image generated in the imaging step, a slag molten metal image region determined to be an image region containing at least one of the slag and the molten metal from the slag image region and the molten metal candidate image region determined in the first region extraction step; and an occupancy rate processing step of determining, as a bare metal area rate, the occupancy rate of the image region containing the molten metal based on the slag image region and the molten metal candidate image region determined in the first region extraction step and the slag molten metal image region determined in the second region extraction step.

[0014] Based on the above findings, this molten metal occupancy rate measurement method determines the occupancy rate of the image area where the molten metal is reflected as the bare metal area rate, and therefore can more accurately determine the occupancy rate of the image area where the molten metal, not slag, is reflected. In other words, the molten metal occupancy rate measurement method can more accurately detect the image area where slag is reflected.

[0015] Another aspect of the present invention provides a molten metal occupancy rate measuring device that includes an imaging unit that generates a color image of the inside of a container containing molten metal, a first area extraction unit that determines a molten metal candidate image area that is determined to be a candidate image area that captures the molten metal based on a green image of the green component in the color image generated by the imaging unit, a second area extraction unit that determines a thin slag image area that is determined to be an image area that captures the thin slag among the molten metal candidate image areas determined by the first area extraction unit based on a red image of the red component in the color image generated by the imaging unit, and an occupancy rate processing unit that determines the occupancy rate of the image area that captures the molten metal as a bare metal area rate based on the molten metal candidate image area determined by the first area extraction unit and the thin slag image area determined by the second area extraction unit.The thin slag is formed from the molten oxide without containing the graphite powder, unlike ordinary slag that is formed from a molten oxide and graphite powder. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the occupancy rate processing unit determines the image area obtained by excluding the thin slag image area obtained by the second area extraction unit from the molten metal candidate image area obtained by the first area extraction unit as the molten metal image area in which the molten metal is captured, and determines the occupancy rate of the determined molten metal image area as the bare metal area rate.

[0016] Based on the above findings, this molten metal area ratio measuring device calculates the area ratio of the image area where the molten metal is reflected as the bare metal area ratio, so it can more accurately calculate the area ratio of the image area where the molten metal, not the slag, is reflected. In other words, the molten metal area ratio measuring device can more accurately detect the image area where the slag is reflected. Note that, since the red image can distinguish between the slag molten metal image area and the thin slag image area, the second area extraction unit can be defined from the perspective of the slag molten metal image area, but can also be defined from the perspective of the thin slag image area.

[0017] In another aspect, the above-mentioned molten metal occupancy rate measuring device further includes an operation execution determination unit that determines whether or not to obtain the bare molten metal area rate based on the brightness value within a predetermined execution determination image area in the color image generated by the imaging unit.

[0018] Such a molten metal occupancy rate measuring device further includes an arithmetic execution determination unit, so that it can determine whether or not the slag removal work is in progress, and it becomes possible to obtain the bare molten metal area rate only during the slag removal work.

[0019] In another aspect, the above-described molten metal occupancy rate measuring device further includes a region adjustment unit that adjusts the extracted image regions used by the first and second region extraction units based on the color image generated by the imaging unit, wherein the first region extraction unit extracts the molten metal candidate image region from a predetermined extracted image region in the color image, and the second region extraction unit extracts the thin slag image region from the extracted image region in the color image. Preferably, in the above-described molten metal occupancy rate measuring device, the extracted image region is represented by a mask image that masks an image, and the first region extraction unit extracts the extracted image region by masking the color image or a green image of a green component in the color image with the mask image, and determines the molten metal candidate image region from the extracted extracted image region, and the second region extraction unit extracts the extracted image region by masking the color image or a red image of a red component in the color image with the mask image, and determines the thin slag image region from the extracted extracted image region. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the region adjustment unit selects one extraction image area from a plurality of different extraction image areas as the extraction image area to be used by each of the first and second region extraction units, based on the color image generated by the imaging unit. Preferably, in the above-mentioned molten metal occupancy rate measuring device, the imaging unit is arranged so that its optical axis is fixed, the extraction image area is an internal image area that captures the internal area of ​​the container as viewed from above by the imaging unit and is represented by a mask image that masks the image, the plurality of extraction image areas are represented by a plurality of mask images corresponding to each of a plurality of tilt angles of the container, and the region adjustment unit selects, from a plurality of mask images corresponding to each of the plurality of extraction image areas, a mask image that best matches the internal image area that captures the internal area of ​​the container in the color image generated by the imaging unit, as the mask image for the extraction image area to be used by each of the first and second region extraction units.

[0020] Such a molten metal occupancy rate measuring device further includes an area adjustment unit, which makes it possible to adjust the extracted image area according to the actual angle at which the container is tilted, thereby making it possible to more accurately determine the occupancy rate of the image area that includes molten metal, rather than slag.

[0021] Another aspect of the present invention provides a molten metal occupancy measurement method, comprising: an imaging process for generating a color image of the inside of a vessel containing molten metal, the imaging process including a first region extraction process for determining a molten metal candidate image area that is determined to be a candidate image area that includes the molten metal based on a green image of the green component in the color image generated in the imaging process; a second region extraction process for determining a thin slag image area that is determined to be an image area that includes the thin slag among the molten metal candidate image areas determined in the first region extraction process based on a red image of the red component in the color image generated by the imaging unit; and a region extraction process for determining the region occupancy of the image area that includes the molten metal as a bare metal area ratio based on the molten metal candidate image area determined in the first region extraction process and the thin slag image area determined in the second region extraction process. The thin slag is formed from the molten oxide without the graphite powder, unlike ordinary slag formed from a molten oxide and graphite powder.

[0022] Based on the above findings, this molten metal occupancy rate measurement method determines the occupancy rate of the image area where the molten metal is reflected as the bare metal area rate, and therefore can more accurately determine the occupancy rate of the image area where the molten metal, not slag, is reflected. In other words, the molten metal occupancy rate measurement method can more accurately detect the image area where slag is reflected. [Effects of the Invention]

[0023] The molten metal occupancy rate measuring device and molten metal occupancy rate measuring method according to the present invention can more accurately determine the occupancy rate of an image area that includes molten metal, rather than slag. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a block diagram showing the configuration of a molten metal occupancy rate measuring device according to an embodiment. [Figure 2] 3 is a diagram illustrating the arrangement of an imaging unit with respect to a chicken pot, which is an example of a container, in the molten metal occupancy rate measuring device. FIG. [Figure 3] 4 is a diagram for explaining a calculation execution determination unit of the molten metal occupancy rate measuring device. FIG. [Figure 4] 3 is a diagram for explaining an area adjusting unit of the molten metal occupancy rate measuring device. FIG. [Figure 5] 10A and 10B are diagrams for explaining a mask image used in the region adjustment unit; [Figure 6] 3A and 3B are diagrams showing an example of a color image generated by an imaging unit of the molten metal occupancy rate measuring device and a color image generated from the color image. [Figure 7] 4A and 4B are diagrams for explaining a first method for extracting a slag image region and a molten metal candidate image region in the molten metal occupancy rate measuring device. [Figure 8] 10 is a diagram for explaining a second method for extracting a slag image region and a molten metal candidate image region in the molten metal occupancy rate measuring device. FIG. [Figure 9] 4 is a diagram for explaining a method for extracting a slag molten metal image region in the molten metal occupancy rate measuring device. FIG. [Figure 10] 4 is a flowchart showing the operation of the molten metal occupancy rate measuring device. [Figure 11] FIG. 10 is a diagram showing the change over time in the bare bath area ratio as an example. [Figure 12] As an example, this is an explanatory diagram showing the distribution of slag and molten iron with respect to pixel values ​​for each color image at each temperature. DETAILED DESCRIPTION OF THE INVENTION

[0025] 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 addition, components with the same reference numerals in each drawing indicate the same components, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual component, a reference numeral with a subscript is used.

[0026] The molten metal occupancy rate measuring device in one embodiment includes an imaging unit that generates a color image of the interior of a vessel containing molten metal, a first region extraction unit that determines, based on a green image of the green component in the color image generated by the imaging unit, a slag image region that is determined to be an image region that includes slag and a molten metal candidate image region that is determined to be a candidate image region that includes the molten metal, a second region extraction unit that determines, based on a red image of the red component in the color image generated by the imaging unit, a slag molten metal image region that is determined to be an image region that includes at least one of the slag and the molten metal, from the slag image region and the molten metal candidate image region determined by the first region extraction unit, and a occupancy rate processing unit that determines, as a bare metal area rate, the occupancy rate of the image region that includes the molten metal, based on the slag image region and the molten metal candidate image region determined by the first region extraction unit and the slag molten metal image region determined by the second region extraction unit. Alternatively, the molten metal occupancy rate measuring device includes an imaging unit that generates a color image of the inside of a container containing molten metal, a first area extraction unit that determines a molten metal candidate image area that is determined to be a candidate image area that captures the molten metal based on a green image of the green component in the color image generated by the imaging unit, a second area extraction unit that determines a thin slag image area that is determined to be an image area that captures the thin slag among the molten metal candidate image areas determined by the first area extraction unit based on a red image of the red component in the color image generated by the imaging unit, and an occupancy rate processing unit that determines the occupancy rate of the image area that captures the molten metal as a bare metal area rate based on the molten metal candidate image area determined by the first area extraction unit and the thin slag image area determined by the second area extraction unit, and the thin slag is formed from the molten oxide without containing the graphite powder, unlike ordinary slag that is formed from a molten oxide and graphite powder. Such a molten metal occupancy rate measuring device and a molten metal occupancy rate measuring method implemented therein will be described in more detail below.

[0027] FIG. 1 is a block diagram showing the configuration of a molten metal occupancy rate measuring device according to an embodiment. FIG. 2 is a diagram illustrating the arrangement of an imaging unit relative to a ladle, which is an example of a vessel, in the molten metal occupancy rate measuring device. FIG. 2A is a side view. FIG. 2B is a diagram illustrating the height of the imaging unit relative to the ladle in a vertical plane, and FIG. 2C is a diagram illustrating the orientation (angle) of the imaging unit relative to the ladle in a horizontal plane. FIG. 3 is a diagram illustrating the calculation execution / determination unit of the molten metal occupancy rate measuring device. FIG. 3A shows an example of a color image generated by imaging unit 1 when slag removal is being performed (during slag removal), and FIG. 3B shows an example of a color image generated by imaging unit 1 when slag removal is not being performed (during non-slag removal). FIG. 4 is a diagram illustrating the area adjustment unit of the molten metal occupancy rate measuring device. FIG. 4A is a diagram illustrating the starting point SP of the comparison line CLt in the color image generated by the image capture unit 1, and FIG. 4B is a diagram illustrating the comparison line CLt in the color image generated by the image capture unit 1. FIG. 5 is a diagram illustrating the mask image used in the region adjustment unit. FIG. 5A shows, as an example, a mask image MPa when the inclination angle of the ladle IA is 32°, and FIG. 5F shows, as an example, a color image PCa generated by the image capture unit 1 when the inclination angle of the ladle IA is 32°. FIG. 5B shows, as an example, a mask image MPb when the inclination angle of the ladle IA is 35°, and FIG. 5G shows, as an example, a color image PCb generated by the image capture unit 1 when the inclination angle of the ladle IA is 35°. FIG. 5C shows, as an example, a mask image MPc when the inclination angle of the ladle IA is 38°, and FIG. 5H shows, as an example, a color image PCc generated by the image capture unit 1 when the inclination angle of the ladle IA is 38°. FIG. 5D shows, as an example, a mask image MPd when the inclination angle of ladle IA is 41°, and FIG. 5I shows, as an example, a color image PCd when the inclination angle of ladle IA is 41°, generated by image capture unit 1. FIG. 5E shows, as an example, a mask image MPe when the inclination angle of ladle IA is 44°, and FIG. 5J shows, as an example, a color image PCe when the inclination angle of ladle IA is 44°, generated by image capture unit 1. FIG. 6 shows an example of a color image generated by the image capture unit of the molten metal occupancy rate measuring device and a color image generated from the color image.FIG. 6A shows an example of the color image, FIG. 6B shows an example of a green image generated from the color image shown in FIG. 6A, and FIG. 6C shows an example of a red image generated from the color image shown in FIG. 6A. FIG. 7 is a diagram illustrating a first extraction method for a slag image region and a molten metal candidate image region in the molten metal occupancy rate measurement device. FIG. 7A is a diagram illustrating a method for discriminating between a slag image region and a molten metal candidate image region using a first region determination threshold Thr1, and FIG. 7B is a diagram illustrating a first method for generating the first region determination threshold Thr1. FIG. 8 is a diagram illustrating a second extraction method for a slag image region and a molten metal candidate image region in the molten metal occupancy rate measurement device. FIG. 8A is a diagram illustrating a method for discriminating between a slag image region and a molten metal candidate image region using a first region determination threshold Thr1, and FIG. 8B is a diagram illustrating a second method for generating the first region determination threshold Thr1. FIG. 9 is a diagram illustrating a method for extracting a slag / molten metal image region in the molten metal occupancy rate measurement device.

[0028] The molten metal occupancy rate measuring device D in the embodiment includes, for example, an imaging unit 1, a control processing unit 2, an input unit 3, an output unit 4, an interface unit (IF unit) 5, and a memory unit 6, as shown in FIG.

[0029] The imaging unit 1 is connected to the control processing unit 2 and generates a color image of the interior of a vessel containing molten metal under the control of the control processing unit 2. The molten metal may be any molten metal (including alloys) as long as slag floats on its surface, such as molten pig iron. The imaging unit 1 is, for example, a color digital camera equipped with an imaging optical system that forms an optical image of the target on a predetermined imaging plane, an area image sensor whose light-receiving surface is aligned with the imaging plane and converts the optical image of the target into an electrical signal, and an image processing unit that processes the output of the area image sensor to generate image data representing the image of the target. The vessel may be any vessel, but one example is a ladle. For example, as shown in FIG. 2, the imaging unit 1 is positioned above the bottomed cylindrical ladle IA so that the optical axis of the imaging unit 1 coincides with the central axis of the ladle IA in its non-slag-removing position, allowing for a bird's-eye view of the interior of the ladle IA. Here, the imaging unit 1 is preferably positioned at a height relative to the dragger DR so as to avoid dust and smoke generated when the dragger DR removes sludge, as shown in FIG. 2B, and is preferably positioned at an angle relative to the dragger DR so as to avoid the dust and smoke, as shown in FIG. 2C.

[0030] The input unit 3 is connected to the control processing unit 2 and is a device that inputs various commands, such as a command to start monitoring, and various data necessary for operating the molten metal occupancy rate measuring device D, such as the temperature of the molten metal, to the molten metal occupancy rate measuring device D, and is, for example, a plurality of input switches to which predetermined functions are assigned, a keyboard, a mouse, etc. The output unit 4 is connected to the control processing unit 2 and is a device that outputs the commands, data, bare metal area ratio, etc. input from the input unit 3 in accordance with the control of the control processing unit 2, and is, for example, a display device such as a CRT display, an LCD (liquid crystal display), or an organic EL display, or a printing device such as a printer.

[0031] The input unit 3 and the output unit 4 may be configured as a touch panel. In this case, the input unit 3 is a position input device, such as a resistive or capacitive type, that detects and inputs an operation position, and the output unit 4 is a display device. In this touch panel, a position input device is provided on the display surface of the display device, and one or more input content candidates that can be input to the display device are displayed. When a user touches the display position showing the input content they want to input, the position is detected by the position input device, and the display content displayed at the detected position is input to the molten metal occupancy rate measuring device D as the user's operation input content. With such a touch panel, the user can easily intuitively understand the input operation, providing a molten metal occupancy rate measuring device D that is easy for the user to use.

[0032] The IF unit 5 is connected to the control processing unit 2 and is a circuit that inputs and outputs data to and from, for example, an external device under the control of the control processing unit 2, and is, for example, an interface circuit for RS-232C, which is a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, an interface circuit using the USB standard, etc. The IF unit 5 may also be, for example, a communication interface circuit that transmits and receives communication signals to and from an external device, such as a data communication card or a communication interface circuit conforming to the IEEE802.11 standard, etc.

[0033] The storage unit 6 is connected to the control processing unit 2 and is a circuit that stores various predetermined programs and various predetermined data under the control of the control processing unit 2. The various predetermined programs include, for example, a control processing program, and the control processing program includes, for example, a control program that controls each of the units 1, 3 to 6 of the molten metal occupancy rate measuring device D according to the function of each unit, a calculation execution determination program that determines whether or not to obtain a bare metal area ratio based on the brightness value within a predetermined execution determination image area in the color image generated by the imaging unit 1, a first area extraction program that determines a slag image area determined to be an image area in which slag is captured and a molten metal candidate image area determined to be a candidate image area in which molten metal is captured based on the green image of the green component in the color image generated by the imaging unit 1, and a red component in the color image generated by the imaging unit 1. The programs include a second area extraction program that determines, based on an image, a slag molten metal image area that is determined to be an image area that captures at least one of the slag and the molten metal from among the slag image area and the molten metal candidate image area determined by the first area extraction program; an area adjustment program that adjusts the extracted image areas used in each of the first and second area extraction programs based on a color image generated by the imaging unit 1; and an occupancy processing program that determines the occupancy rate of the image area that captures the molten metal as a bare metal area rate based on the slag image area and the molten metal candidate image area determined by the first area extraction program and the slag molten metal image area determined by the second area extraction program.The first region extraction program may be a program for determining a molten metal candidate image region determined to be a candidate image region containing the molten metal based on a green image of a green component in the color image generated by the imaging unit 1, the second region extraction program may be a program for determining a thin slag image region determined to be a candidate image region containing the thin slag based on a red image of a red component in the color image generated by the imaging unit 1, and the occupancy rate processing program may be a program for determining the occupancy rate of the image region containing the molten metal as a bare metal area rate based on the molten metal candidate image region determined by the first region extraction program and the thin slag image region determined by the second region extraction program. The various predetermined data include, for example, data required for executing each of these programs, such as a mask image representing the extracted image region, various thresholds, the color image captured by the imaging unit 1, and a color image of a predetermined color component. Such storage unit 6 includes, for example, a ROM (Read Only Memory) which is a nonvolatile storage element, an EEPROM (Electrically Erasable Programmable Read Only Memory) which is a rewritable nonvolatile storage element, etc. The storage unit 6 also includes a RAM (Random Access Memory) which serves as a so-called working memory of the control processing unit 2 and stores data generated during execution of the predetermined program, etc. The storage unit 6 may also be configured to include a hard disk device with a relatively large storage capacity.

[0034] The control processing unit 2 is a circuit that controls each of the units 1, 3 to 6 of the molten metal occupancy rate measuring device D according to the function of each unit, and determines the occupancy rate of the image area where the molten metal is captured as the bare metal area rate. The control processing unit 2 is configured, for example, with a CPU (Central Processing Unit) and its peripheral circuits. By executing a control processing program, the control processing unit 2 functionally includes a control unit 21, an operation execution determination unit 22, an area adjustment unit 23, a first area extraction unit 24, a second area extraction unit 25, and an occupancy rate processing unit 26.

[0035] Control unit 21 controls each of units 1, 3 to 6 of molten metal occupancy rate measuring device D according to the function of each unit, and is responsible for overall control of molten metal occupancy rate measuring device D. When control unit 21 determines the occupancy rate of the image area capturing the molten metal (bare metal area rate), control unit 21 causes imaging unit 1 to generate a color image showing an overhead view of the inside of the vessel containing the molten metal, and acquires the color image from imaging unit 1. This generation and acquisition of color images is performed repeatedly, for example, at a predetermined sampling interval.

[0036] The calculation execution determination unit 22 determines whether or not to obtain the bare bath area ratio based on the brightness value in a predetermined execution determination image region in the color image generated by the imaging unit 1.

[0037] The molten metal occupancy rate measuring device D may continuously and repeatedly determine the bare metal area ratio at predetermined sampling intervals while the blast furnace is in operation. However, since the bare metal area ratio is determined mainly for the purpose of properly removing slag, it only needs to be determined during the slag removal operation to remove the slag, and does not need to be determined when the slag removal operation is not in progress. The slag removal operation is often performed by tilting a vessel containing molten metal (in the example shown in FIG. 2, ladle IA). If the imaging unit 1 is fixedly disposed relative to the vessel, tilting the vessel will change the position of the image region that captures the interior of the vessel in the color image generated by the imaging unit 1. Therefore, in the color image generated by the imaging unit 1, a predetermined image region whose brightness value changes depending on whether the slag removal operation is being performed (during slag removal operation) or not (during non-slag removal operation) is set as the execution determination image region. Therefore, it is possible to determine whether the slag removal operation is being performed or not based on the change in brightness value of the execution determination image region, and to determine whether the bare metal area ratio is to be calculated or not. For example, as shown in Fig. 3, a predetermined region (region of interest) ROI is set in advance in the color image generated by the imaging unit 1 as an image region to be subjected to image processing. As shown in Fig. 3A, a boundary line BL is set at the boundary between the region where the interior of ladle IA is reflected and the region where the interior of ladle IA is not reflected during the slag removal operation. The region including the region where the interior of ladle IA is reflected from this boundary line BL is set as the execution determination image region RC. Alternatively, for example, since the slag removal operation is performed while the vessel is storing molten metal, a boundary line BL is set so as to mainly include the area showing the interior of ladle IA during the slag removal operation, and the execution determination image region RC is set to an area from this boundary line BL that includes the area showing the interior of ladle IA during the slag removal operation. When the execution determination image region RC is set in this manner, the brightness value within this execution determination image region RC becomes relatively high during the slag removal operation because the image shown in Figure 3A is generated, and becomes relatively low during the non-slag removal operation because the image shown in Figure 3B is generated.For this reason, a brightness threshold (execution determination threshold) Thc for distinguishing between the slag removal operation and the non-slag removal operation is appropriately set in advance, and the calculation execution determination unit 22 compares the brightness value of the execution determination image region in the color image generated by the imaging unit 1 with the execution determination threshold Thc. If the brightness value of the execution determination image region is equal to or greater than the execution determination threshold Thc, it determines that the bare molten metal area ratio is to be calculated. If the brightness value of the execution determination image region is less than the execution determination threshold Thc, it determines that the bare molten metal area ratio is not to be calculated (if the brightness value of the execution determination image region is less than the execution determination threshold Thc, it determines that the bare molten metal area ratio is not to be calculated). When it determines that the bare molten metal area ratio is to be calculated, the molten metal occupancy ratio measuring device D operates the imaging unit 1, the control unit 21, the calculation execution determination unit 22, the region adjustment unit 23, the first region extraction unit 24, the second region extraction unit 25, and the occupancy ratio processing unit 26, and causes the occupancy ratio processing unit 26 to calculate the bare molten metal area ratio by information processing, which will be described later. On the other hand, when it is determined that it is not the time to calculate the bare metal area ratio, the molten metal occupancy ratio measuring device D operates the imaging unit 1, the control unit 21 and the calculation execution determination unit 22 to monitor whether or not to calculate the bare metal area ratio, and stops the operation of at least the occupancy ratio processing unit 26, so as not to cause the occupancy ratio processing unit 26 to calculate the bare metal area ratio.

[0038] The area adjustment unit 23 adjusts the extracted image areas to be used by the first and second area extraction units 24, 25, based on the color image generated by the imaging unit 1. More specifically, there are a plurality of extracted image areas that are different from one another, and the area adjustment unit 23 selects one extracted image area from the plurality of extracted image areas as the extracted image area to be used by each of the first and second area extraction units 24, 25, based on the color image generated by the imaging unit 1.

[0039] More specifically, the extracted image area is an internal image area capturing the internal area of ​​the vessel viewed from above by the imaging unit 1, and is represented by a mask image that masks the image. By masking the target image with the mask image, the internal image area is extracted from the target image, and the remaining area excluding the internal image area is changed to a predetermined monochromatic color, resulting in a mask-processed image. In the example shown in FIG. 2, the imaging unit 1 is positioned so that its optical axis is fixed. Therefore, when ladle IA, an example of the vessel, is tilted, the position of the internal image area in the color image generated by the imaging unit 1 changes. Therefore, the multiple extracted image areas are represented by multiple mask images corresponding to multiple tilt angles of ladle IA. In the molten metal occupancy rate measuring device D, multiple mask images corresponding to multiple different tilt angles are prepared in advance, and these multiple mask images are stored in the memory unit 6. For example, mask images MPa to MPe with inclination angles of 32°, 35°, 38°, 41°, and 44° shown in Figures 5A to 5E are created in advance by referring to color images MPf to MPj with inclination angles of 32°, 35°, 38°, 41°, and 44° shown in Figures 5F to 5J, and stored in storage unit 6. From among the mask images corresponding to the plurality of extracted image regions, region adjustment unit 23 selects a mask image that best matches an internal image region capturing the internal region of the container in the color image generated by imaging unit 1 as a mask image of the extracted image region to be used in first and second region extraction units 24 and 25, respectively. More specifically, in selecting this mask image, the contour of the internal image region in the color image generated by imaging unit 1 is compared with the contour of the extracted image region in the mask image, and the mask image having the contour of the extracted image region that best matches the contour of the internal image region is selected. For example, as shown in FIG. 4, when an XY Cartesian coordinate system is set in a planar view, with the lower left vertex of the color image CP generated by the imaging unit 1 as the coordinate origin, the horizontal direction as the X axis, and the vertical direction as the Y axis, the region adjustment unit 23 extracts, from the region of interest ROI in the color image generated by the imaging unit 1, a pixel whose X coordinate value is the smallest and whose brightness value is equal to or greater than a predetermined threshold value, as a starting point SP.In the example shown in FIG. 4A, point (x1, y1) is extracted as the start point SP. Next, the region adjustment unit 23 extracts a predetermined length of the contour of the internal image region in the color image generated by the imaging unit 1 from the extracted start point as the comparison line of the internal image region. The contour can be extracted, for example, by image processing using an edge filter that extracts edges. In the example shown in FIG. 4B, a portion of the contour of the internal image region is extracted as the comparison line CLt of the internal image region. The predetermined length is appropriately set in advance so that the correlation between the contour of the internal image region and the contour of the extracted image region can be analyzed. The region adjustment unit 23 then calculates the correlation value between each comparison line of each mask image similarly extracted from each mask image stored in the storage unit 6 and the comparison line of the internal image region, selects the comparison line of the mask image that gives the highest correlation value, and selects the mask image having the selected comparison line as the mask image of the extracted image region to be used by the first and second region extraction units 24 and 25, respectively. In calculating the correlation value, for example, the distance to the comparison line of the mask image is calculated for each of a plurality of points on the comparison line of the internal image region, and the sum of these calculated distances is calculated as the correlation value, in which case the smaller the correlation value (the sum), the higher the correlation. Note that each comparison line of each mask image may be calculated in advance and stored in storage unit 6, and used as described above.

[0040] The first region extraction unit 24 determines a slag image region determined to be an image region containing slag and a molten metal candidate image region determined to be a candidate image region containing molten metal, based on a green image of the green component in the color image generated by the imaging unit 1. The green image is an image in which the green pixel value (G value) of each pixel in the color image is used as the pixel value of each pixel. For example, the green image shown in FIG. 6B is generated from the color image generated by the imaging unit 1 shown in FIG. 6A. More specifically, the first region extraction unit 24 determines the slag image region and the molten metal candidate image region within a predetermined extracted image region in the color image generated by the imaging unit 1.

[0041] More specifically, the first region extraction unit 24 extracts the extracted image region by masking the color image generated by the imaging unit 1 or the green image of the green component in the color image with the mask image, and then determines the slag image region and the molten metal candidate image region within the extracted extracted image region. For example, the first region extraction unit 24 extracts the extracted image region by masking the color image generated by the imaging unit 1 with the mask image. In the masking process, the pixel values ​​of each pixel are extracted directly from the color image corresponding to the extracted image region and set as the pixel values ​​of each pixel in the extracted image region, while the pixel values ​​of each pixel in the remaining region excluding the extracted image region are set to 0. Therefore, as a result of the masking process, an image is generated in which the extracted image region is set as the color image of the extracted image region and the remaining region is set as black. Next, the first region extraction unit 24 generates a green image of the green component in the generated image. This generates a masked green image in which the green pixel value (G value) of each pixel in the color image of the extracted image region is set as the pixel value of each pixel, while the remaining region remains black. The first region extraction unit 24 then determines the slag image region and the molten metal candidate image region within the extracted image region in the masked green image. Alternatively, for example, the first region extraction unit 24 extracts the extracted image region by masking a green image based on the color image generated by the imaging unit 1 with the mask image. In the masking process, the pixel values ​​of each pixel in the green image corresponding to the extracted image region are extracted as they are and set as the pixel values ​​of each pixel in the extracted image region, while the pixel values ​​of each pixel in the remaining region excluding the extracted image region are set to 0. Therefore, as a result of the masking process, a masked green image similar to that described above is generated, in which the extracted image region is set as the green image of the extracted image region and the remaining region is set as black. The first region extraction unit 24 then determines the slag image region and the molten metal candidate image region within the extracted image region in the generated masked green image. That is, either the generation of the green image or the mask processing can be performed first.

[0042] According to the inventor's findings, the green image can be divided into a slag image region determined to be an image region containing slag and a molten metal candidate image region determined to be a candidate image region containing molten metal. Therefore, the slag image region and the molten metal candidate image region are extracted using a threshold (first region determination threshold) Thr1, as shown in FIGS. 7A and 8A, respectively. More specifically, the first region extraction unit 24 compares the pixel value (G value) of each pixel in the extracted image region in the green image after processing the generated mask with the first region determination threshold Thr1. If the pixel value (G value) of the pixel is greater than (or equal to or greater than) the first region determination threshold Thr1, the first region extraction unit 24 determines that the pixel is a pixel in the molten metal candidate image region. If the pixel value (G value) of the pixel is less than (or equal to) the first region determination threshold Thr1, the first region extraction unit 24 determines that the pixel is a pixel in the slag image region. If thin slag or flames are captured in the color image, the image region containing the thin slag or flames is included in the molten metal candidate image region. In this embodiment, the thin slag is defined as slag formed from molten oxides without graphite powder, as opposed to ordinary slag formed from molten oxides and graphite powder. The first region determination threshold Thr1 is changed depending on the temperature of the molten metal contained in the container. For example, as shown in FIG. 7B, information (temperature threshold correspondence information) representing the correspondence between temperature and the first region determination threshold Thr1 is created in advance, and the created temperature threshold correspondence is stored in the memory unit 6. The temperature threshold correspondence may be expressed in the form of a function formula, as shown in FIG. 7B, or in the form of a table (not shown). The first region extraction unit 24 determines, from the temperature threshold correspondence information stored in the memory unit 6, a first region determination threshold Thr1 corresponding to, for example, a temperature input by an operator (user) from the input unit 3, or a temperature measured by a temperature sensor (e.g., a thermocouple, etc.) that measures the temperature of the molten metal contained in the container when the molten metal occupancy rate measuring device D is further equipped with the temperature sensor, and uses this determined first region determination threshold Thr1 to determine the slag image region and the molten metal candidate image region.Alternatively, as shown in FIG. 8B , the first region extraction unit 24 creates a histogram representing the frequency of each pixel value (G value) (class) within the extracted image region in the green image after mask processing, determines the most frequent luminance peak (class), calculates the luminance value (peak luminance value) Bp of the determined luminance peak, and determines a luminance value that is smaller than the determined peak luminance value Bp by a predetermined value as the first region determination threshold Thr1. For example, the first region extraction unit 24 multiplies the determined peak luminance value Bp by a predetermined scaling factor α (0.5<α<1) and determines the result as the first region determination threshold Thr1. Since the profile of the histogram changes depending on the temperature of the molten metal contained in the container, the first region determination threshold Thr1 generated by this second generation method is changed depending on the temperature of the molten metal contained in the container.

[0043] The second region extraction unit 25, based on the red image of the red component in the color image generated by the imaging unit 1, determines a slag molten metal image region determined to be an image region that includes at least one of the slag and the molten metal among the slag image region and the molten metal candidate image region determined by the first region extraction unit 24. The red image is an image in which the red pixel value (R value) of each pixel in the color image is used as the pixel value of each pixel. For example, the red image shown in FIG. 6C is generated from the color image generated by the imaging unit 1 shown in FIG. 6A. More specifically, the second region extraction unit 25 determines the slag molten metal image region within a predetermined extracted image region in the color image generated by the imaging unit 1.

[0044] More specifically, the second region extraction unit 25 extracts the extracted image region by masking the color image generated by the imaging unit 1 or a red image of the red component in the color image with the mask image, and then determines the molten slag metal image region within this extracted extracted image region. For example, the second region extraction unit 25 extracts the extracted image region by masking the color image generated by the imaging unit 1 with the mask image, as described above. Next, the second region extraction unit 25 generates a red image after the mask processing by taking the red pixel value (R value) of each pixel in the color image of the extracted image region as the pixel value of each pixel and leaving the remaining region black. Then, the second region extraction unit 25 determines the molten slag metal image region within the extracted image region in the generated red image after the mask processing. Alternatively, for example, the second region extraction unit 25 extracts the extracted image region by masking the red image based on the color image generated by the imaging unit 1 with the mask image. In the masking process, the pixel values ​​of each pixel are extracted directly from the red image corresponding to the extracted image area and set as the pixel values ​​of each pixel in the extracted image area, while the pixel values ​​of each pixel in the remaining area excluding the extracted image area are set to 0. Therefore, as a result of the masking process, a masked red image is generated in which the extracted image area is set as the red image of the extracted image area and the remaining area is set as black. The second area extraction unit 25 then determines the molten slag metal image area within the extracted image area in the generated masked red image. In other words, the generation of the red image and the masking process can be performed in any order.

[0045] The red image can be divided into a molten slag image region, which is determined to be an image region containing at least one of the slag and the molten metal, and a thin slag image region, which is determined to be an image region containing thin slag. Therefore, the molten slag image region is extracted using a threshold (second region determination threshold) Thr2, as shown in FIG. 9. More specifically, the second region extraction unit 25 compares the pixel value (R value) of each pixel in the extracted image region in the red image after processing the generated mask with the second region determination threshold Thr2. If the pixel value (R value) of the pixel is greater than (or equal to or greater than) the second region determination threshold Thr2, the second region extraction unit 25 determines that the pixel belongs to a thin slag image region determined to be an image region containing thin slag. If the pixel value (R value) of the pixel is less than (or equal to) the second region determination threshold Thr2, the second region extraction unit 25 determines that the pixel belongs to a molten slag image region. If a flame is captured in the color image, the image area containing the flame is included in the thin slag image area. The second area determination threshold Thr2 is set in advance, for example, from a plurality of samples.

[0046] The occupancy rate processing unit 26 calculates the occupancy rate of the image area containing the molten metal as the bare molten metal area rate based on the slag image area and molten metal candidate image area calculated by the first area extraction unit 24 and the molten metal slag image area calculated by the second area extraction unit 25. More specifically, the occupancy rate processing unit 26 calculates a residual image area by excluding the molten metal slag image area calculated by the second area extraction unit 25 from the slag image area and molten metal candidate image area calculated by the first area extraction unit 24, calculates the molten metal image area by excluding the residual image area from the molten metal candidate image area calculated by the first area extraction unit 24, and calculates the occupancy rate of the calculated molten metal image area as the bare molten metal area rate. When molten metal, slag, thin slag, and a flame are reflected in the color image, the slag is reflected in the slag image region, the molten metal, the thin slag, and the flame are reflected in the molten metal candidate image region, and the slag and the molten metal are reflected in the slag-molten metal image region. Therefore, since the thin slag and the flame are reflected in the residual image region, the image region in which the molten metal is reflected (molten metal image region) is determined by subtracting the residual image region from the molten metal candidate image region, and the bare molten metal area ratio, which is the occupancy rate of the image region in which the molten metal is reflected, is determined ((bare molten metal area ratio) = (area of ​​molten metal image region) / ((area of ​​slag image region) + (area of ​​molten metal candidate image region))). Since the area of ​​an image region can be expressed, for example, by the number of pixels, the bare molten metal area ratio can be determined based on the number of pixels in each image region.

[0047] As can be seen from the above, the first area extraction unit 24 may determine a molten metal candidate image area that is determined to be a candidate image area that captures the molten metal based on a green image of the green component in the color image generated by the imaging unit 1, and the second area extraction unit 25 may determine a thin slag image area that is determined to be an image area that captures the thin slag from among the molten metal candidate image areas determined by the first area extraction unit 24 based on a red image of the red component in the color image generated by the imaging unit 1.In this case, the occupancy rate processing unit 26 may determine the occupancy rate of the image area that captures the molten metal as a bare metal area rate based on the molten metal candidate image area determined by the first area extraction unit 24 and the thin slag image area determined by the second area extraction unit 25. More specifically, the first region extraction unit 24 extracts the extracted image region by masking the color image generated by the imaging unit 1 or the green image of the green component in the color image with the mask image, and determines the molten metal candidate image region within this extracted extracted image region. The second region extraction unit 25 extracts the extracted image region by masking the color image generated by the imaging unit 1 or the red image of the red component in the color image with the mask image, and determines the thin slag image region within this extracted extracted image region. The occupancy rate processing unit 26 determines the image region obtained by excluding the thin slag image region obtained by the second region extraction unit 25 from the molten metal candidate image region obtained by the first region extraction unit 24 as the molten metal image region containing the molten metal, and determines the occupancy rate of the determined molten metal image region as the bare metal area ratio.

[0048] The control processing unit 2, input unit 3, output unit 4, IF unit 5, and storage unit 6 can be configured by, for example, a desktop or notebook computer. The computer configuring each of these units 2 to 6 may be placed, for example, in an operation room in a plant such as a blast furnace or converter, and may be incorporated into a console (or may serve as the console), or may be separate from the console.

[0049] Next, the operation of this embodiment will be described. Fig. 10 is a flowchart showing the operation of the molten metal occupancy rate measuring device. Fig. 11 is a diagram showing, as an example, the change in bare molten area rate over time. The horizontal axis of Fig. 11 represents elapsed time, and the vertical axis represents the bare molten area rate [%].

[0050] When the power is turned on, the molten metal occupancy rate measuring device D having such a configuration initializes the necessary parts and starts its operation. By executing the control processing program, the control processing unit 2 is functionally configured with a control unit 21, a calculation execution determination unit 22, a region adjustment unit 23, a first region extraction unit 24, a second region extraction unit 25, and a occupancy rate processing unit 26.

[0051] At the sampling timing, in FIG. 10, the molten metal occupancy rate measuring device D first causes the control unit 21 of the control processing unit 2 to generate a color image in the imaging unit 1, and acquires the color image from the imaging unit (S1).

[0052] Next, the molten metal occupancy rate measuring device D determines whether or not to obtain the bare molten metal area ratio based on the brightness value in a predetermined execution determination image region in the color image generated by the imaging unit 1 in process S1, using the calculation execution determination unit 22 of the control processing unit 2 (S2). If the result of this determination is that the bare molten metal area ratio is to be obtained (Yes), the molten metal occupancy rate measuring device D then executes process S3, while if the result of the above determination is that the bare molten metal area ratio is not to be obtained (No), the molten metal occupancy rate measuring device D then executes process S8.

[0053] In this process S3, the molten metal occupancy rate measuring device D adjusts the extracted image areas used in the first and second area extraction units 24 and 25, respectively, based on the color image generated by the imaging unit 1 in process S1, using the area adjustment unit 23 of the control processing unit 2.

[0054] Next, the molten metal occupancy rate measuring device D determines the slag image area and the molten metal candidate image area for the green image within the extracted image area adjusted in process S3 based on the color image generated by the imaging unit 1 in process S1 using the first area extraction unit 24 of the control processing unit 2 (S4).

[0055] Next, the molten metal occupancy rate measuring device D determines the slag molten metal image area for the red image within the extracted image area adjusted in process S3 based on the color image generated by the imaging unit 1 in process S1 using the second area extraction unit 25 of the control processing unit 2 (S5).

[0056] Next, the molten metal occupancy rate measuring device D, using the occupancy rate processing unit 26 of the control processing unit 2, calculates the occupancy rate of the image area containing the molten metal as the bare metal area rate based on the slag image area and molten metal candidate image area calculated in process S4 and the slag molten metal image area calculated in process S5 (S6).

[0057] In addition, in process S4, the first area extraction unit 24 determines the molten metal candidate image area, in process S5, the second area extraction unit 25 determines the thin slag image area, and in process S6, the occupancy rate processing unit 26 may determine the bare metal area ratio based on these molten metal candidate image area and thin slag image area.

[0058] Next, the molten metal occupancy rate measuring device D outputs the bare molten metal area ratio calculated in step S6 to the output unit 4 by the control unit 21 of the control processing unit 2 (S7). For example, a display device as an example of the output unit 4 displays the bare molten metal area ratio versus the elapsed time from the start, as shown in Fig. 11. Note that the bare molten metal area ratio calculated in step S6 may be output to an external device via the IF unit 5 as necessary.

[0059] Then, the molten metal occupancy rate measuring device D determines whether or not to terminate this process using the control processing unit 2. If the result of this determination is that the process should be terminated (Yes), the molten metal occupancy rate measuring device D terminates this process. For example, if the input unit 3 has received a command or the like instructing termination, the molten metal occupancy rate measuring device D determines that the process should be terminated. On the other hand, if the result of the determination is that the process should not be terminated (No), the molten metal occupancy rate measuring device D returns the process to step S1.

[0060] The operator (user) refers to the bare molten metal area ratio output to the output unit 4, and determines that the slag removal work is complete if this bare molten metal area ratio is equal to or less than a preset threshold value corresponding to the amount of slag. Note that the determination of whether the slag removal work is complete may be performed by the molten metal occupancy ratio measuring device D, and in this case, the molten metal occupancy ratio measuring device D also outputs the determination result of whether the slag removal work is complete to the output unit 4.

[0061] As described above, the molten metal occupancy rate measuring device D and the molten metal occupancy rate measuring method implemented therein in the embodiment calculate the occupancy rate of the image area where the molten metal is reflected as the bare metal area ratio based on the following findings, and therefore can more accurately calculate the occupancy rate of the image area where the molten metal, not slag, is reflected. In other words, the molten metal occupancy rate measuring device can more accurately detect the image area where slag (including normal slag and thin slag) is reflected.

[0062] The inventors examined a color image of the inside of a container containing molten metal from above and found that better accuracy could be achieved by determining the area of ​​molten metal based on a color image obtained by dividing the color image into its color components, rather than on the color image itself.

[0063] FIG. 12 is an explanatory diagram showing, as an example, the distribution of slag and molten iron relative to pixel values ​​for each color image at each temperature. The upper row of FIG. 12 mainly shows the case where the molten iron temperature is 1262°C, the middle row of FIG. 12 mainly shows the case where the molten iron temperature is 1301°C, and the lower row of FIG. 12 mainly shows the case where the molten iron temperature is 1350°C. In plan view, the first figures from the left in FIG. 12 show color images overlooking the interior of the ladle (for convenience of illustration, these are grayscale monochrome images in FIG. 12). The second figures from the left in FIG. 12 are histograms showing the distribution of slag and molten iron relative to pixel values ​​in the red image, with the horizontal axis representing the red pixel value (R value) (class) and the vertical axis representing frequency. The third figures from the left in Fig. 12 are histograms showing the distribution of slag and molten iron with respect to pixel values ​​in the green image, with the horizontal axis representing the green pixel value (G value) (class) and the vertical axis representing frequency. The fourth figures from the left in Fig. 12 are histograms showing the distribution of slag and molten iron with respect to pixel values ​​in the blue image, with the horizontal axis representing the blue pixel value (B value) (class) and the vertical axis representing frequency.

[0064] As can be seen from the third diagram from the left in Fig. 12, at all temperatures, slag is distributed with a bias toward relatively small green pixel values ​​(G values), while molten iron is distributed with a bias toward relatively large green pixel values ​​(G values). Therefore, the image can be separated into image regions that mainly contain slag and other image regions that mainly contain molten metal using the above-mentioned first region determination threshold Thr1.

[0065] On the other hand, as shown in the second diagram from the left in Figure 12, the brightness of the thin slag saturates in the red component at all temperatures, resulting in a red pixel value of 255 at 256 gradations. Therefore, the red component can be used to effectively separate the molten metal slag image area from the thin slag image area. Therefore, compared to the slag quantification method disclosed in Patent Document 1, which does not separate the image into color components, the molten metal occupancy rate measuring device D and molten metal occupancy rate measuring method of this embodiment are more accurate.

[0066] The bare molten metal area ratio is determined primarily to properly remove slag, and therefore only needs to be determined during the slag removal operation, but does not need to be determined when the slag removal operation is not in progress. The slag removal operation is often performed by tilting a vessel containing molten metal. If the imaging unit is fixedly disposed relative to the vessel, tilting the vessel changes the position of the image area capturing the interior of the vessel in the color image generated by the imaging unit, thereby changing the brightness value of a predetermined image area (the execution determination image area). The molten metal occupancy ratio measurement device D and molten metal occupancy ratio measurement method perform a calculation execution determination, so they can determine whether the slag removal operation is in progress and can determine the bare molten metal area ratio only during the slag removal operation.

[0067] The slag removal work is not always performed with the container tilted at a fixed angle. The molten metal occupancy rate measuring device D and the molten metal occupancy rate measuring method perform area adjustment, making it possible to adjust the extracted image area according to the angle at which the container is actually tilted, and therefore the occupancy rate of the image area that includes molten metal, rather than slag, can be determined with greater accuracy.

[0068] In order to express the present invention, the present invention has been properly and sufficiently described above through the embodiments with reference to the drawings, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims. [Explanation of symbols]

[0069] D. Molten metal occupancy rate measuring device 1. Imaging unit 2. Control processing section 6 Memory section 21 Control Unit 22 Calculation execution determination unit 23 Area adjustment section 24 First area extraction part 25 Second area extraction part 26 Occupancy rate processing section

Claims

1. an imaging unit that generates a color image of the interior of a vessel containing molten metal; a first area extraction unit that determines a slag image area that is determined to be an image area that includes slag and a molten metal candidate image area that is determined to be a candidate image area that includes the molten metal, based on a green image of a green component in the color image generated by the imaging unit; A second area extraction unit extracts a slag molten metal image area that is determined to be an image area that includes at least one of the slag and the molten metal, from among the slag image area and the molten metal candidate image area obtained by the first area extraction unit, based on a red image of the red component in the color image generated by the imaging unit; and an occupancy rate processing unit that calculates the occupancy rate of the image area in which the molten metal is captured as a bare metal area rate based on the slag image area and the molten metal candidate image area calculated by the first area extraction unit and the slag molten metal image area calculated by the second area extraction unit. Molten metal occupancy rate measuring device.

2. The image capturing unit further includes a calculation execution determination unit that determines whether or not to calculate the bare bath area ratio based on a luminance value within a predetermined execution determination image region in the color image generated by the image capturing unit. The molten metal occupancy rate measuring device according to claim 1 .

3. The first region extraction unit obtains the slag image region and the molten metal candidate image region within a predetermined extracted image region in the color image, The second region extraction unit obtains the molten metal slag image region within the extracted image region in the color image, further comprising a region adjusting unit that adjusts the extracted image regions used by the first and second region extracting units based on the color image generated by the imaging unit; The molten metal occupancy rate measuring device according to claim 1 .

4. an imaging step of generating a color image of an overhead view of the interior of a vessel containing molten metal; a first area extraction step of determining a slag image area determined to be an image area containing slag and a molten metal candidate image area determined to be a candidate image area containing the molten metal, based on a green image of a green component in the color image generated in the imaging step; A second area extraction step of determining a slag molten metal image area that is determined to be an image area that includes at least one of the slag and the molten metal from among the slag image area and the molten metal candidate image area determined in the first area extraction step based on a red image of the red component in the color image generated in the imaging step; and an occupancy rate processing step of calculating an occupancy rate of the image area including the molten metal as a bare metal area rate based on the slag image area and the molten metal candidate image area calculated in the first area extraction step and the slag molten metal image area calculated in the second area extraction step. Molten metal occupancy rate measurement method.

5. an imaging unit that generates a color image of the interior of a vessel containing molten metal; a first area extraction unit that determines a molten metal candidate image area that is determined to be a candidate image area that includes the molten metal based on a green image of a green component in the color image generated by the imaging unit; A second area extraction unit that determines a thin slag image area that is determined to be an image area that includes thin slag, from the molten metal candidate image area determined by the first area extraction unit, based on a red image of the red component in the color image generated by the imaging unit; an occupancy rate processing unit that calculates the occupancy rate of the image area in which the molten metal is captured as a bare metal area rate based on the molten metal candidate image area calculated by the first area extraction unit and the thin slag image area calculated by the second area extraction unit; The thin slag is formed from a melt of the oxides without the graphite powder, as opposed to a conventional slag formed from a melt of the oxides and graphite powder. Molten metal occupancy rate measuring device.

6. The image capturing unit further includes a calculation execution determination unit that determines whether or not to calculate the bare bath area ratio based on a luminance value within a predetermined execution determination image region in the color image generated by the image capturing unit. The molten metal occupancy rate measuring device according to claim 5.

7. the first region extraction unit obtains the molten metal candidate image region within a predetermined extracted image region in the color image; The second region extraction unit obtains the thin slag image region within the extracted image region in the color image, further comprising a region adjusting unit that adjusts the extracted image regions used by the first and second region extracting units based on the color image generated by the imaging unit; The molten metal occupancy rate measuring device according to claim 5.

8. an imaging step of generating a color image of an overhead view of the interior of a vessel containing molten metal; a first area extraction step of determining a molten metal candidate image area that is determined to be a candidate image area that includes the molten metal based on a green image of a green component in the color image generated in the imaging step; A second area extraction process for determining a thin slag image area, which is determined to be an image area including thin slag, from the molten metal candidate image area determined in the first area extraction process based on a red image of the red component in the color image generated in the imaging process; and an occupancy rate processing step of determining an occupancy rate of the image area in which the molten metal is projected as a bare metal area rate based on the molten metal candidate image area determined in the first area extraction step and the thin slag image area determined in the second area extraction step, The thin slag is formed from a melt of the oxides without the graphite powder, as opposed to a conventional slag formed from a melt of the oxides and graphite powder. Molten metal occupancy rate measurement method.

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