Technical field
[0001]The present invention relates to a slag detection method in the molten steel flow.
Priority is claimed on Japanese Patent Application No. 2017-025440 filed in Japan on February 14, 2017, which is incorporated herein by reference.
BACKGROUND
[0002]When the converter of steel out of the ladle, it is common to efflux converter a is tilted molten steel flow toward the ladle from a converter furnace. At this time, the slag was remaining converter furnace, it is ideal to flow out only the molten steel ladle from a converter furnace. However, the molten steel stream flowing toward the ladle from a converter furnace, although only substantially molten steel is present in the tapping early, to coexist with the molten steel and slag in the tapping end of tapping metaphase There is common. Therefore, the attempt to prevent the outflow of slag, the molten steel yield remains the rolling furnace tends to be low.
[0003]On the other hand, an attempt to reduce the residual amount of the molten steel in the converter in order to slag with the molten steel flows out toward the ladle, so that the slag is often present in the ladle. As a result, there is a possibility that boiling over may occur slag from ladle, such as the components out of the molten steel is generated in the secondary refining process is post-process problems.
[0004]Therefore, it quantifies the outflow of slag and detects slag of the molten steel stream flowing toward the ladle from a converter furnace, controlling the slag outflow in the range required in the tapping operation of the converter it has been desired.
[0005]Higher than emissivity emissivity of the molten steel slag, when imaging the flow of molten steel, in the site where the slag is present, a slag is brighter imaging as compared to a site only molten steel absent. In other words, the concentration of the pixel area corresponding to the slag in the captured image obtained by imaging the flow of molten steel (gray level) is greater than the density of the pixel area corresponding to the molten steel. As a technique for detecting slag using this principle, for example, a method described in Patent Document 1.
[0006]Patent Document 1, for the captured image obtained by imaging the flow of molten steel, the concentration (intensity) and the horizontal axis, to create a concentration (luminance) histogram to the longitudinal axis the number of pixels, using the density histogram slag It discloses a method of detecting. Specifically, in the method of Patent Document 1, the density histogram is regarded as the number of pixels is the maximum peak point is the maximum (the maximum peak position) corresponds to the molten steel, considering the direction of the axis of abscissas of the maximum peak point variation σ with determining the density value (luminance value) N1 or more pixels with the molten steel, and the density value obtained by adding the bias value B to the density value N1 (luminance value) N2 or more pixels determined to slag.
[0007]However, the present inventors have studied, not necessarily the maximum peak point is necessarily correspond to the molten steel in the density histogram, it was found that may correspond to the slag. Therefore, be regarded as the maximum peak point is always correspond to the molten steel, in the above Patent Document 1 a method of determining the density value N2, it is difficult to accurately detect the slag.
[0008]Here, if the peak in the density histogram is one, emissivity and molten steel emissivity is different slag (emissivity of the slag is higher than the emissivity of the molten steel) by utilizing the corresponding peak is the molten steel considered either it can determine whether corresponding to slag. Also, if the peak in a smooth curve to the density histogram is as present twice, utilizing vary the emissivity and molten steel emissivity of the slag, for example, the peak on the low temperature side corresponds to the molten steel, hot It is considered to be determined as the peak of the side corresponds to the slag.
However, if the molten steel and the slag is observed a plurality of sub-peaks in the histogram of the captured image obtained by imaging the molten steel flow mixed, it is difficult to use the method described above, is a fear that the detection accuracy of the slag is lowered is there.
The temperature of the molten steel flow, for example, also changes 100 ° C. or higher depending on the condition of the steel grade or tapping operations. Therefore, an attempt to determine using a fixed threshold value, when the temperature of the molten steel flow is changed, there is a possibility that the detection accuracy of the slag is lowered.
CITATION
Patent Document
[0009]
Patent Document 1: Japanese Patent 2006-213965 JP
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　The present invention has been made in view of the above circumstances, even when the temperature of the molten steel flow is changed, a slag in the molten steel flow accurately detectable, provided the slag detection method in the molten steel flow for the purpose.
Means for Solving the Problems
[0011]
　To solve the above problems, the present inventors have conducted extensive studies. First, the present inventors, using a thermal imaging camera (thermography) having a main sensitivity to the infrared region as an imaging device, tapping initial images the tapping metaphase, and various molten steel flow across the tapping end to obtain a large number of captured images. Then, for each of these captured images, the temperature on the horizontal axis, was to create a histogram with the vertical axis the number of pixels, for example in a temperature range of the horizontal axis of 1000 ~ 2000 ° C., the number of pixels on the vertical axis maximum value may the maximum peak point exists is, the maximum peak point in some cases located on the low temperature side was found that the maximum peak point is also located on the high temperature side.
[0012]
　Then, the present inventors have found that with the case where only the case or very small amounts there is no slag in the molten steel flow exists, the maximum peak point in the histogram is found to be located on and the low temperature side corresponds to the molten steel, the molten steel If the slag is present in large amounts in the flow, the maximum peak point in the histogram is found to be located on and the high temperature side corresponds to the slag. However, as mentioned above, since the temperature of the molten steel flow changes, using a fixed threshold for temperature, or the maximum peak point is located on either the low temperature side and high temperature side threshold value of the fixed by determining, if the maximum peak point is determined whether corresponding to either of the molten steel and slag, it is difficult to accurately detect the slag.
[0013]
　Therefore, the present inventors have carried out further extensive studies. The present inventors have found that in the histogram of the image pickup image of the molten steel stream containing molten steel and slag, in addition to the maximum peak point, and a predetermined number of pixels threshold number of pixels is less than the number of pixels of the maximum peak point (e.g., up to 50 percent of the number of pixels of the peak point) or more peak points are local maxima (hereinafter referred to as "intermediate peak point") focused on that may be present. In such a case, the present inventors have found that for example even if the temperature of the molten steel flow in accordance with the conditions of the steel grade or tapping operations has changed, when the maximum peak point corresponds to the molten steel, than the temperature of the maximum peak point the number of intermediate peak point having a high temperature were found to be larger than the number of intermediate peak point having a temperature lower than the temperature of the maximum peak point.
　Further, the present inventors have found that even if the temperature of the molten steel flow in accordance with the conditions of the steel grade or tapping operations has changed, when the maximum peak point corresponds to the slag, the temperature lower than the temperature of the maximum peak point the number of intermediate peak point having were found to be larger than the number of intermediate peak point having a temperature higher than the temperature of the maximum peak point.
[0014]
　In the above has been described by way of temperature as an example, it has been found that can be said also similar for the histogram of the density before the conversion to the temperature and the horizontal axis. Also, the captured image obtained by imaging the flow of molten steel by using a CCD camera having a main sensitivity in a visible light region, the density on the horizontal axis, the same thing that is true for the generated histogram the number of pixels on the vertical axis It was found.
[0015]
　Based on the above findings, the present invention employs the following in order to solve the above problems.
　(1) slag detection method of the molten steel flow in accordance with one embodiment of the present invention, flows toward the ladle from a converter furnace, an imaging step of acquiring a captured image by capturing the molten steel stream comprising molten steel and slag; by performing image processing on the captured image, and a concentration parameter corresponding to the density of the pixels constituting the captured image as the horizontal axis, and the vertical axis the number of pixels is a total number of the pixels having the concentration parameter for the histogram, the maximum peak point detection step and the number of pixels for detecting the maximum peak point is the maximum value; histogram generation process and to create a histogram of the said histogram, the number of pixels of the number of pixels is the maximum peak point the concentration parameter of the maximum peak point; intermediate peak point detecting step and that and detecting an intermediate peak point is a maximum value equal to or larger than a predetermined number of pixels threshold below The number Nh of the intermediate peak point having a larger concentration parameter also an intermediate peak point counting step of counting and the number of intermediate peak point Nl having a small concentration parameter than said concentration parameter of the maximum peak point; the number If Nl is greater than the number Nh, the one that the maximum peak point is determined corresponding to the slug, if the number Nh is greater than the number Nl, the maximum peak is determined that the maximum peak point corresponding to the molten steel having; and the point type determining step.
　(2) In the aspect described in (1) above, it may be configured as follows: the at the maximum peak point type determination step, when said maximum peak point is determined to correspond to the slag, the maximum peak point pixels having density parameter less than the first threshold determined based on the response to the molten steel, the first determination step of determining a pixel having a first threshold value or more concentration parameter corresponding to the slug when, in the maximum peak point type determination step, when said maximum peak point is determined to correspond to the molten steel, a pixel having a density parameter of the following second threshold determined based on the maximum peak point is the molten steel ; corresponding to the pixel having a larger concentration parameter than the second threshold value and the second determination step determines that corresponding to the slug
further comprising a.
　In the aspect described in (3) above (2) may be configured as follows: the first threshold value, in the histogram, first straight line and having a positive slope as the maximum peak point in represented; the second threshold value, in the histogram, the expressed maximum peak point in a second straight line having a street and negative slope; the absolute value of the slope of the second straight line, said first larger than the absolute value of a straight line of slope.
　(4) In the aspect described in the above (3), configuration may be as follows: the first straight line, said and said maximum peak point has the number of pixels smaller than the number of pixels threshold among the points having a small concentration parameter greater than a predetermined value relative to the concentration parameter, and the density parameter is the maximum of the peak point, be a straight line passing through the said maximum peak point; absolute value of the slope of the second straight line, the from 1.5 to 2.5 times the absolute value of the slope of the first line.
Effect of the invention
[0016]
　According to the above aspect of the present invention, even when the temperature of the molten steel flow is changed, it can be accurately detected slag in the molten steel flow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
It is a schematic diagram showing a schematic configuration of a slag detection device used in slag detection method according to an embodiment of FIG. 1 the present invention.
FIG. 2 is a flowchart showing a schematic procedure of the slag detection process.
It is a diagram illustrating an example of a captured image acquired in the imaging step ST1 shown in FIG. 3A] FIG.
The histogram generation step ST2 shown in FIG. 3B] FIG. 2 is a diagram showing a histogram created based on the captured image of FIG. 3A.
Is a diagram for explaining a first threshold value which is determined in the first determination step ST7 shown in FIG. 4 FIG.
An example of a captured image acquired in the imaging step ST1 shown in FIG. 5A] FIG. 2 is a diagram illustrating different examples and Figure 3A.
The histogram generation step ST2 shown in FIG. 5B] FIG. 2 is a diagram showing a histogram created based on the captured image of FIG. 5A.
It is a diagram for explaining a second threshold which is determined in the second determination step ST8 shown in FIG. 6 FIG.
[FIG 7A] is a diagram for explaining a slag detection method described in Patent Document 1.
Is a diagram showing a captured image used to create the histogram of FIG. 7B] Figure 7A.
Is a diagram illustrating a FIG. 8 result slag S is extracted by differential processing of the pixel region that exists in the captured image illustrated in Figure 3A.
DESCRIPTION OF THE INVENTION
[0018]
　Hereinafter, with reference to the accompanying drawings, slag detection method of the molten steel flow in accordance with an embodiment of the present invention (hereinafter, simply referred to as "slag detection method") will be described. Incidentally, omitted in the present specification and drawings, are denoted by the same reference numerals to constituent elements having substantially the same functional configurations, and their redundant description.
　First, the configuration of the slag detection device 100 used in slag detection method according to the present embodiment.
[0019]
　
　Fig. 1 is a schematic diagram showing a schematic configuration of the slag detecting device 100. In FIG. 1, a converter 3 which accommodates the molten steel M and slag S is shown in cross-section.
　As shown in FIG. 1, the slag detection device 100, when the steel exits from the converter 3 into ladle 4, molten steel flow F flowing out toward the ladle 4 from tapping nozzle 31 of the converter 3 is tilted used to detect slag S in. Slag detection device 100, connected to the imaging unit 1 substantially taken from the horizontal direction of molten steel flow F flowing substantially vertically towards the ladle 4 from tapping nozzle 31 of the converter 3, in the imaging device 1 images and a processing unit 2.
[0020]
　The imaging unit 1, for example, can be used such as a CCD camera having a main sensitivity to thermal imaging camera (thermography), or visible light region having a main sensitivity to the infrared region. These thermal imaging camera (thermography) and the CCD camera, for example, can be used commercially.
　In the present embodiment, as the imaging device 1 uses a thermal imaging camera having a main sensitivity to the infrared region. In the case of using a thermal image camera (thermography) as in the present embodiment, it is possible to calculate the value of the temperature or concentration of the pixel region in the captured image (density before converting to temperature). On the other hand, when using a CCD camera, it is possible to calculate the value of the density of the pixel area.
[0021]
　Image processing means 2, for example, a general-purpose personal computer in which a predetermined program for executing such histogram creation step ST2 to be described later is installed. The image processing unit 2 includes a monitor for displaying a captured image obtained by the imaging unit 1.
[0022]
　Slag detection method according to the present embodiment is performed using the slag detection device 100. The following describes slag detection method according to the present embodiment.
[0023]
　
　FIG. 2 is a flowchart showing a schematic procedure of the slag detecting method according to the present embodiment.
　Slag detection method according to the present embodiment, flows I directed from the converter 3 into ladle 4, based molten steel flow F comprising a molten steel M and slag S in the captured image obtained by capturing by the imaging means 1, the molten steel a method of detecting slag S in the stream F, as shown in FIG. 2, an imaging step ST1, the histogram generation step ST2, the maximum peak point detection step ST3, an intermediate peak point detection step ST4, the intermediate peak a point counting step ST5, the maximum peak point type determination step ST6, a first determination step ST7, and a second determination step ST8.
　Hereinafter, the contents of each process will be sequentially described.
[0024]
　(Imaging step ST1)
　In the imaging step ST1, the imaging unit 1 acquires a captured image by capturing the molten steel flow F flowing out toward the ladle 4 from the converter 3 (see FIG. 1).
　In the present embodiment, by using a thermal imaging camera as the imaging device 1, the captured image acquired by the imaging step ST1 will those terms of temperature the density of each pixel constituting the captured image with a predetermined conversion formula . In other words, captured image obtained by the imaging step ST1 has a value of temperatures detected for each pixel.
[0025]
　Field of the imaging means 1, so as not to be affected by the outflow position and extent variations of molten steel flow F, is set to a wide field of view to include a background not molten steel flow F only. Even if the field of view of the imaging means 1 is configured to be in the background, because the temperature of the background is lower than the temperature of the molten steel flow F, at the maximum peak point detection step ST3 will be described later, the pixel region corresponding to the molten steel flow F it is possible to identify a pixel region corresponding to the background with. Note that the field of view of the imaging unit 1, only the molten steel flow F may be previously narrowed adjusted to be imaged. However, the outflow position and extent of the molten steel flow F, in accordance with the tilt angle of the converter 3 (depending on the position of the tapping nozzle 31), it is common to vary to some extent. Therefore, tapping initial, tapping metaphase and that only the molten steel flow F in any of tapping the end to adjust the field of view of the imaging unit 1 to be imaged requires labor work. Accordingly, the field of view of the imaging means 1 is preferably set to a wide field of view to include a background.
[0026]
　Imaging timing of the imaging unit 1 is not particularly limited, in enhancing the time resolution to detect the slag S is continuously every scanning period that are set in the imaging unit 1 (the inverse of the frame rate) it is preferable to imaging.
　Captured image obtained by the imaging means 1 is stored in the image processing unit 2.
[0027]
　(Histogram creation step ST2)
　The histogram creation step ST2, the image processing means 2, by performing image processing on the captured image acquired by the imaging step ST1, transverse concentration parameter corresponding to the density of the pixels constituting the captured image the axis, to create a histogram of the number of pixels is a total number of pixels having the concentration parameter and the vertical axis. It histogram may be created for each of captured images may be generated for average image obtained by averaging a plurality of consecutive captured images. Note that the average case of using the image pickup means 1 of the molten steel flow length L of the molten steel flow F velocity V in a division-obtained time of the pixel region corresponding to F in the field of view (= L / V) in in it is desirable to average a plurality of consecutive captured images.
　Examples of the concentration parameter, other concentrations themselves, can be exemplified temperature. When the imaging unit 1 as in the present embodiment is a thermal imaging camera, the horizontal axis can be created histograms is the temperature or concentration (concentration prior to conversion to the temperature). On the other hand, if the imaging means 1 is a CCD camera, the horizontal axis can be created histograms is the concentration.
[0028]
　Here, the "density" herein, for example, refers to the 256 gradations of the image brightness (i.e., luminance of the image). Then, a the concentration, the relationship between the thermal radiance of the molten steel flow is a linear relationship.
[0029]
　Due to the use of thermal imaging camera as the imaging unit 1 in the present embodiment as described above, using a temperature as above concentration parameter (i.e., in this embodiment, the horizontal axis of the histogram is temperature).
　In the present embodiment, as described above, the field of view of the imaging means 1 is set to also include a background not molten steel flow F only. Therefore, when creating the histogram, the image processing means 2, in the captured image, a predetermined threshold (e.g., 1000 ° C.) pixel area is determined as a pixel area corresponding to the flow of molten steel F having a temperature above , a histogram as an object the pixel region (i.e., the temperature is horizontal axis pixel area of less than the predetermined threshold value is not used for creating the histogram). Thus, it is possible to avoid the influence of the background on the histogram (the number of pixels corresponding to the background is not a maximum).
　The image processing unit 2 creates a histogram for the entire captured image including also the pixel area corresponding to the background, from the detection range of the maximum peak point at the maximum peak point detection step ST3 will be described later, a predetermined threshold (e.g. , by excluding the temperature below 1000 ° C.), it may avoid the influence of the background.
[0030]
　Figure 3A is a diagram showing an example of a captured image acquired in the imaging step ST1. Specifically, FIG. 3A, the resolution of which is an example of an average image of the five captured images continuously acquired for each scan period of the image pickup means 1 and averaged (captured image is about 3 cm / pixel ). In Figure 3A, it is displayed by cutting only partially about the pixel region corresponding to the background is located in the vicinity and the pixel area corresponding to the molten steel flow F in the captured image (average image). In other words, captured image actually acquired, than captured images shown in FIGS. 3A and 5A, the pixel region of the left-right direction is wider.
　Furthermore, captured image convenience of illustration shown in FIG. 3A, although a monochrome display, in fact, the monitor image processing means 2 is provided, different colors depending on the temperature of each pixel is assigned the display It is. That is, the temperature of the pixel area corresponding to the molten steel flow F is higher than the temperature of the pixel region corresponding to the background, in the actual captured image obtained by the imaging step ST1, is colored a color corresponding to the high temperatures there.
　Also, among the pixel regions corresponding to the molten steel flow F, is surrounded by a thick broken line in FIG. 3A, the pixel region (specifically considered slag S is present, corresponding to the slag S in the first determination step ST7 below Then the temperature determination area of pixels) (the apparent temperature) is higher than the temperature of the other pixel region (region of pixel substantially only the molten steel M is present) (the apparent temperature), its color corresponding to a high temperature are colored.
　Incidentally, in the molten steel flow F discharged from the converter 3, and the actual temperature of the portion corresponding to the pixel region slag S is present (actual temperature), a portion corresponding to a pixel region where substantially only the molten steel M is present the actual temperature (actual temperature) of the considered equivalent value. However, the emissivity of the slag S is higher than the emissivity of the molten steel M (emissivity of slag compared to the emissivity of the molten steel is approximately 1.5 times), any setting of emissivity in the image pickup unit 1 for to the same for the pixels is generally, as mentioned above, in the obtained captured image, the temperature of the pixel region where the slag S is present, substantially of the pixel region where only the molten steel M is present It is determined to be higher than the temperature. The same applies to FIG. 5A will be described later.
　Figure 3B is a diagram showing a histogram created captured image (average image) shown in FIG. 3A. Upon creation of the histogram of Figure 3B, in order to avoid the influence of the background, the temperature range of the horizontal axis with a predetermined threshold value (1000 ° C.) or higher (although, 1400 ° C. did not show a characteristic distribution of the number of pixels not shown) for less than, the horizontal axis is divided at 10 ° C. pitch, the vertical axis is the number of pixels having a temperature of each section.
[0031]
　(Maximum peak point detection step ST3)
　in the maximum peak point detection step ST3, the image processing means 2, the histogram created by the histogram creation step ST2, the number of pixels for detecting the maximum peak point is the maximum value. In the histogram shown in FIG. 3B, a point indicated by reference numeral P1 is the maximum peak point.
[0032]
　(Intermediate peak point detection step ST4)
　the intermediate peak point detection step ST4, the image processing means 2, the histogram created by the histogram creation step ST2, and a predetermined number of pixels Mr less than the number of pixels of the maximum peak point P1 number of pixels detecting an intermediate peak point is a maximum value of more than threshold Th. Pixel number threshold value Th, as shown in Figure 3B, is set to 50% of the number of pixels of the maximum peak point P1. In the histogram shown in FIG. 3B, a point indicated by reference numeral P2 is an intermediate peak point.
[0033]
　The predetermined number of pixels threshold Th, but are not particularly limited, 1200 ° C. ~ not to capture the peak temperature region that seems Background and such 1300 ° C., for example the number of pixels of the maximum peak point P1 preferably to 50% and Th.
[0034]
　(Intermediate peak point counting step ST5)
　the intermediate peak point counting step ST5, the image processing means 2, of the intermediate peak point P2 detected, the number of intermediate peak point P2 having a temperature higher than the temperature of the maximum peak point P1 Nh When counts the number Nl of the intermediate peak point P2 having a temperature lower than the temperature of the maximum peak point P1 respectively. In Figure 3B, the Nh = 1, Nl = 6.
[0035]
　(Maximum peak point type determining step ST6)
　in the maximum peak point type determination step ST6, (when the number Nl is greater than the number Nh) image processing means 2, when the number Nh number Nl, the maximum peak point P1 corresponds to molten steel M present in the molten steel flow F to. In Figure 3B, since it is Nh = 1, Nl = 6, Nh aX + b will be determined to correspond to the molten steel M which is present in the molten steel flow F.
　On the other hand, the image processing unit 2 determines that a pixel having a first threshold value or more temperature corresponds to the slag S present in the molten steel flow F. That determines that Y ≦ aX + b pixels satisfying the (pixel in the region hatched in FIG. 4) corresponds to the slag S present in the molten steel flow F.
[0040]
　(Second determination step ST8)
　at the maximum peak point type determination step ST6, a maximum peak point P1 when it determines that corresponds to the molten steel M which is present in the molten steel flow F, the image processing unit 2 performs a second determination step ST8.
　Figure 5A is an example of a captured image acquired in the imaging step ST1, a diagram showing other different examples and Figure 3A. Specifically, Figure 5A shows another example of the average image of the five captured images continuously acquired for each scan period of the image pickup means 1 and averaged.
　Figure 5B is a diagram showing a histogram created captured image (average image) shown in FIG. 5A. The histogram of FIG. 5B, at an intermediate peak point counting step ST5, the image processing means 2, the number Nh = 5 intermediate peak point P2 having a temperature higher than the temperature of the maximum peak point P1, the temperature of the maximum peak point P1 counts even the number Nl = 0 of the intermediate peak point P2 having a lower temperature. Accordingly, it is determined in the subsequent maximum peak point type determination step ST6, the image processing unit 2 are the number Nh> number Nl, the maximum peak point P1 corresponding to the molten steel M which is present in the molten steel flow F and.
　By the determination is made at the maximum peak point type determination step ST6, the image processing unit 2 performs a second determination step ST8. In the second determination step ST8, the image processing means 2, among the pixels constituting the captured image, pixels having a second threshold temperature below which was determined based on the maximum peak point P1 is the molten steel flow F It corresponds to the molten steel M which is present, determines that the pixels having a temperature higher than the second threshold value corresponds to the slag S present in the molten steel flow F. Hereinafter, with reference to FIG. 6 as appropriate, it will be described more specifically.
[0041]
　Figure 6 is a diagram for explaining a second threshold which is determined in the second determination step ST8. Incidentally, the histogram shown in FIG. 6 is the same as the histogram shown in Figure 5B.
　As shown in FIG. 6, the second threshold value is expressed by the second straight line L2 with the street and negative slope of the maximum peak point P1. If the absolute value is the larger are (preferably towards the slope of the second straight line L2 than the absolute value of the inclination of the first straight line L1, the absolute value of the slope of the second straight line L2 is the inclination of the first straight line L1 of 1.5 to 2.5 times the absolute value). The first straight line L1 is a straight line passing through the P3 and the maximum peak point P1 points shown in FIG. Since the point P3 is the slope of a line between a point adjacent to the low temperature side positive, as in FIG. 4, the temperature of the maximum peak point P1 and has a number of pixels less than the number of the threshold value Th pixels predetermined value TD (e.g., 50 ° C.) than among the points having a temperature lower than a peak point with the highest temperature.
[0042]
　As described above, the first straight line L1, the temperature of the horizontal axis is X, and the number of pixels in the vertical axis and Y, will be expressed by the following equation (1).
　Y = aX + b ··· (1 )
　where, a is a positive constant, b is a constant. These constants are determined from the first straight line L1 passes through the point P3 and the maximum peak point P1.
[0043]
　On the other hand, for example, when the absolute value of the slope of L2 of the second straight line is to be set to twice the absolute value of the slope a of the first straight line L1, the second straight line L2, it is represented by the following formula (2) become.
　Y = -2aX + c ··· (2 )
　where, a is a positive constant, c is a constant. Then, a is determined from the first straight line L1, c is determined from the second straight line passing through the maximum peak point P1.
[0044]
　As described above, the image processing unit 2 determines that a pixel having a second threshold temperature below corresponds to the molten steel M which is present in the molten steel flow F. That is, for example, in the histogram shown in FIG. 6, the pixels which satisfy Y ≦ -2aX + c will be determined to correspond to the molten steel M which is present in the molten steel flow F.
　On the other hand, the image processing unit 2 determines that a pixel having a temperature higher than the second threshold value corresponds to the slag S present in the molten steel flow F. That is, for example, in the histogram shown in FIG. 6, (a pixel in the region hatched in Figure 6) the pixel which satisfies Y> -2aX + c will be determined to correspond to the slag S present in the molten steel flow F.
[0045]
　According to slag detection method according to the present embodiment described above, based on the magnitude relation of the number Nh and Nl intermediate peak point in the histogram of the obtained captured image, it determines the type of the maximum peak point of the histogram. That is, in order to determine the type of the maximum peak point, without using a fixed threshold, even when the temperature of the molten steel flow F is changed, the maximum peak point P1 corresponding to one of the molten steel M or slag S or it is possible to accurately determine.
[0046]
　Incidentally, slag detection method according to the present embodiment, it is assumed when the number Nh and the number Nl is different from each other (Nh ≠ Nl). That is, when the number Nh and the number Nl are equal (Nh = Nl), by the method described above, it is impossible to determine the type of the maximum peak point.
　Therefore, either when the number Nh and the number was counted in the middle peak point counting step ST5 Nl are equal to each other, a maximum peak point P1 by the method (i) or (ii) shown below, for example corresponding to one of the molten steel M or slag S the judges.
　Based on the actual temperature and emissivity of (i) the molten steel flow, leave estimated maximum peak point P1 is the temperature when the temperature and the maximum peak point P1 in the case corresponding to the molten steel M corresponds to the slag S respectively, determined depending whether the temperature of the maximum peak point P1 of the histogram of interest is close to any of these temperatures determines the type of the maximum peak point.
　(Ii) the amount of slag and the molten steel of the converter 3 is be estimated and either a geometrically estimated possible if caused to what extent tilt the converter 3 molten steel flow F in which the molten steel M mainly flows out based on that it determines the maximum peak point P1 corresponds to any of the molten steel M or slag S from the outflow time of the molten steel flow F.
[0047]
　Further, according to the slag detection method according to the present embodiment, in the first determination step ST7 or second determination step ST8, the number of pixels corresponding to the slag S present in the molten steel flow F (area), the molten steel flow F the number of pixels corresponding to the molten steel M which present the (area) can be calculated. Thus, for example, it can be determined the area ratio of the slag S in the molten steel flow F, and the volume fraction of the slag S in the molten steel flow F. By using further the specific gravity of the molten steel M and slag S, it is possible to calculate the mass ratio of the slag S in the molten steel flow F, flow rate of the molten steel flow F can be estimated from the inclination angle of the converter 3 when the tapping . Therefore, by using the flow rate of the mass ratio and the molten steel flow F of the slag S, it is possible to estimate runoff slag S a (flow), tapping operation of the converter 3 the outflow amount of slag S it becomes possible to control the range that is required in.
　Specifically, according to the slag detection method according to the present embodiment, or to exit the tapped operation if the outflow amount of the slag S (outflow, the number of pixels, the area, etc. volume) is greater than zero termination or the tapped operation if the outflow amount of the slag S is greater than a predetermined value, if the ratio of the outflow amount of the slag S against outflow amount of the molten steel M is greater than a predetermined value the it is possible to perform the control such as to terminate the tapping operation.　
Example
[0048]
　Next, a description will be given of an embodiment carried out for confirming the effect of the present invention.
[0049]
　Using the captured image shown in FIG. 3A as the evaluation target, and slag detection method according to the present embodiment was compared with the slag detection method described in Patent Document 1.
　Specifically, the slag detecting method according to the present embodiment, as described above, the histogram shown in FIG. 3B was developed for the captured image shown in FIG. 3A, the slug S to the maximum peak point P1 is present in the molten steel flow F It is determined corresponding with. Then, as shown in FIG. 4, the first straight line L1 represented by the formula (1), a pixel in the region hatched is determined to correspond to the slag S.
　In the example shown in FIG. 4, 139 pixels is determined to correspond to the slag S.
[0050]
　On the other hand, the use of slag detection method described in Patent Document 1, the maximum peak point P1 in the histogram shown in FIG. 3B is considered to correspond to the molten steel M which is present in the molten steel flow F. As described above, the slag detecting method described in Patent Document 1, the horizontal axis direction of the dispersion density value N1 or more pixels consideration σ of the maximum peak point P1 is determined that the molten steel M, the bias value to the density value N1 B have determined that the slag S concentration value N2 or more pixels by adding the. Replacing the density value of the temperature, the slag detecting method described in Patent Document 1, the temperature N1 or more pixels horizontal axis variation σ also considering the maximum peak point P1 is determined that the molten steel M, the bias value to the temperature N1 the temperature N2 or more pixels obtained by adding B will determine that a slug S. Here, the slag detecting method described in Patent Document 1, since the maximum peak point P1 is considered to correspond to the molten steel M, the bias value B for distinguishing between pixels corresponding to the pixels and the slag S corresponding to the molten steel M set to at least 2 [sigma] (i.e., the temperature N2 set to at least the temperature + sigma of the maximum peak point P1) it is reasonable. In this evaluation, using the minimum value 2σ most detection error of slag S is decreased as the bias value B. The pixel of the histogram shown in FIG. 3B, assuming that the temperature or the number of pixels distribution of the maximum peak point P1 is a normal distribution, the temperature of the maximum peak point P1 to a temperature N2 (temperature of the maximum peak point P1 + sigma) the sum of the number, divided by the sum of the number of or more pixels temperature of the maximum peak point P1 is set to σ to approximately 68%.
[0051]
　7A and 7B are diagrams for explaining a slag detection method described in Patent Document 1. Figure 7A is a histogram, FIG. 7B shows a captured image (average image). Histogram shown in FIG. 7A is the same as the histogram shown in FIG. 3B or FIG. Captured image shown in FIG. 7B is the same as the captured image shown in Figure 3A. According to the slag detection method described in Patent Document 1, a pixel in the region hatched in FIG. 7A is determined to correspond to the slag S. Specifically, 18 pixels in the pixel area surrounded by a thick broken line in FIG. 7B is determined to correspond to the slag S.
[0052]
　Figure 8 is a graph showing a result of extracting the difference processing pixel region thought that slag S is present in the captured image illustrated in Figure 3A. Incidentally, FIG. 8 (a) the same captured image and FIG. 3A, a captured image of the molten steel flow substantially only the molten steel M is present in FIG. 8 (b) tapping an initial, FIG. 8 (c) Figure shows the difference image between captured image shown in the captured image and FIG. 8 (b) shown in 8 (a).
　Figure 8 is on for convenience of illustration, although a monochrome display, the difference image shown in FIG. 8 (c), the pixel area corresponding to the high pixel area (background temperature as compared to the pixel area corresponding to the background color (green) and color different from (yellow, red) pixel area that is attached) is decreased temperature toward the periphery from the center, and, extended vertically elongated with the fall of the molten steel flow F and Considering the embodiment has a pixel region thought slag S is present. High pixel region of this temperature when counting the number of pixels of the (yellow, red pixel region attached), was 111 pieces.
[0053]
　Thus, if the true value of the number of pixels corresponding to 111 amino assessed by the differential image to the slag S, slag detection method according to the present embodiment, Tasu25.2% of the true value ((139-111) / 111 × whereas the error of 100 = 25.2), the slag detecting method described in Patent Document 1, -83.8% of the true value ((18-111) /111×100=-83.8) It was of error. Therefore, according to the slag detection method according to the present embodiment, as compared with the slag detection method described in Patent Document 1, it can be said that the slag S in the molten steel flow F is accurately detectable. This is more of a thick broken line shown in FIG. 3A, as compared to the thick broken line shown in FIG. 7B, a point close to the outline of the pixel region thought that the slag S shown in FIG. 8 (c) are present, visual manner it is also evident.
[0054]
　Incidentally, when converting the number of pixels corresponding to the slag S as assessed by the difference image in the area (actual size), the area of one pixel is about 9cm 2 for a, 9 × 111 = 999Cm 2 becomes. Simply Convert volume this (converted visual axis dimension of the imaging unit 1 of the slag S is assumed to be the same as the dimension in the viewing plane of the image pickup means 1) Then, (999) 3/2 = 31575Cm 3 31575 × 10 = -6 m 3 a. Therefore, the specific gravity of the slag S 2 × 10 -3 m 3 When / kg, the mass of slag S is, (31575 × 10 -6 ) / (2 × 10 -3 a) = 16 kg.
　Similarly, when converting the slag S detected by the slag detection method according to the present embodiment mass 22 kg (137.5% of the true value), and the slag S detected by the slag detection method described in Patent Document 1 by weight made in terms with 1 kg (6.3% of the true value). That is, according to the slag detection method according to the present embodiment, it is mass at + 37.5% error, as compared to the method described in Patent Document 1, an error of -93.7% occurs, slag in the molten steel flow F S said to the be accurately detectable.
[0055]
　Having described the embodiments of the present invention, the above embodiments have been presented by way of example, the scope of the present invention is not limited to the above embodiment. The embodiments described herein may be embodied in other various forms, without departing from the spirit of the invention, various omissions, substitutions, and changes can be made. The above embodiments and their modifications as would fall within the scope and spirit of the invention, and are included in the invention and the scope of their equivalents are claimed.
[0056]
　For example, in the above embodiment, the first threshold is shown a case represented by the first straight line L1 and having a positive slope as the maximum peak point P1. Relates method of determining the threshold value, from the viewpoint of detecting a slag with higher accuracy, it is preferable to determine by performing fitting, etc. each Gaussian distribution for the peak of the molten steel and slag. However, in such a method, the calculation time becomes long, industrially not preferred. Therefore, by representing the first threshold by a straight line, it determines a threshold value more easily.
[0057]
　The first and second threshold values ​​is not limited to the case represented by the first straight line L1 and the second straight line L2. For example, the first threshold value and second threshold value, considering the horizontal axis direction of the variation of the maximum peak point, may be represented by a straight line perpendicular to the horizontal axis (a straight line of slope is infinite).
DESCRIPTION OF SYMBOLS
[0058]
1: imaging means
2: image processing means
3: the converter
4: ladle
100: slag detection device
ST1: imaging step
ST2: histogram generation step
ST3: maximum peak point detection step
ST4: intermediate peak point detection step
ST5: middle peak point counting step
ST6: peak point type determining step
ST7: first determination step
ST8: second determination step
F: the molten steel flow
M: the molten steel
S: slag

The scope of the claims
[Requested item 1]Flows toward the ladle from a converter furnace, an imaging process and to a retrieval method including the molten steel stream comprising molten steel and slag;
by performing image processing on the captured image, each pixel constituting the captured image ; concentration parameter corresponding to the concentration and the horizontal axis, the histogram creation process and to create a histogram of the number of pixels is a total number of the pixels having the density parameter with the longitudinal axis
up to about the histogram, the number of pixels the maximum peak point detection step and detecting the maximum peak point is the value;
for the histogram, the intermediate peak point the number of pixels is a maximum value of more than a predetermined number of pixels threshold and less than the number of pixels of the maximum peak point an intermediate peak point detection step of detecting a;
number of the intermediate peak point having a larger concentration parameter than said concentration parameter of the maximum peak point h and the maximum peak point of the concentration parameter said intermediate peak point number Nl and the middle peak point counting step of counting and also have a smaller concentration parameter from;
when the number Nl is greater than the number Nh, the maximum while determining the peak point corresponding to the slug, if the number Nh is greater than the number Nl, the maximum peak point and the maximum peak point type determination step of determining to correspond to the molten steel;
and wherein a slag detection method in the molten steel stream.
[Requested item 2]In the maximum peak point type determination step, when said maximum peak point is determined to correspond to the slag, pixels having a density parameter of less than the first threshold determined based on the maximum peak point corresponding to the molten steel and a pixel having a density parameter of more than the first threshold value first determination process and determines that corresponding to the slag;
were determined at the maximum peak point type determination step, the maximum peak point corresponds to the molten steel If the pixel having the second threshold following concentrations parameter determined by the maximum peak point in the reference corresponds to the molten steel, a pixel having a larger concentration parameter than the second threshold value corresponding to said slug ; second determination step and determining a result
slag detection method in the molten steel flow according to claim 1, characterized in that it comprises a further.
[Requested item 3]Wherein the first threshold value, in the histogram, the expressed maximum peak point in a first straight line having a street and a positive slope,
the second threshold value, in the histogram, as the maximum peak point and is represented by a second straight line having a negative slope,
the absolute value of the second slope of the line is greater than the absolute value of the slope of the first linear
flow of molten steel according to claim 2, characterized in that slag detection method in.
[Requested item 4]The first straight line, among the points having a small concentration parameter greater than a predetermined value with respect to the concentration parameter of and the maximum peak point has the number of pixels smaller than the number of pixels threshold, the density parameter is maximum a peak point, a straight line passing through the said maximum peak point,
the absolute value of the slope of the second straight line is 1.5 to 2.5 times the absolute value of the slope of the first straight line
and wherein the slag detection method in the molten steel flow according to claim 3.