Shape measurement method, quality management method, and manufacturing method for belt-like substrate, and shape measurement device and manufacturing facility of belt-like substrate

Abstract

To provide a technique that allows easy and stable operation of shape determination and can reduce maintenance cost.SOLUTION: A shape measurement method for a belt-like substrate includes: an imaging step of picking up images of both sides of a belt-like substrate; an image processing step of calculating a shape index of the belt-like substrate from the obtained images; and a determination step of performing shape quality determination for the belt-like substrate on the basis of the obtained shape index. A quality management method includes, by using the method, cutting and removing a section determined to have a defective shape in a longitudinal direction of the belt-like substrate. A manufacturing method includes, by using the shape measurement method, changing the manufacturing specifications of the belt-like substrate so that the obtained shape index falls within a range of a predetermined shape index determined in advance. A shape measurement device of a belt-like substrate comprises: imaging means that continuously picks up images of both sides of a belt-like substrate being conveyed; image processing means that calculates a shape index of the belt-like substrate from the obtained images; and determination means that performs shape quality determination for the belt-like substrate on the basis of the obtained shape index.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a shape measurement method, a quality control method, a manufacturing method, and a shape measurement device and manufacturing facility for a strip-shaped substrate such as a hot-rolled steel sheet. [Background technology]

[0002] In the materials industry, shape management of strip-shaped substrates is important, and quantification of product shapes has been required. For example, there is a high demand for measuring the shape of steel materials in steelmaking processes from the viewpoints of operational stability and product quality assurance. In particular, shape measurement during rolling to produce a product into the desired shape is important because it leads to improved product quality and operational stability by providing feedback for initial setting of rolling conditions and for rolling control during rolling.

[0003] For example, in a manufacturing line for hot-rolled steel sheets as shown in Fig. 1, that is, in a hot rolling facility 100, the steel sheets are manufactured as follows. First, a rectangular parallelepiped semi-finished product called a slab in a high-temperature state extracted from a heating furnace is processed into a sheet-shaped hot-rolled steel sheet S through processes of width adjustment by a sizing mill, rough rolling by a rough rolling mill, and finish rolling by a finishing rolling mill 1. Thereafter, the temperature is adjusted in a cooling zone 2, and the steel sheet S is wound up by a coiler 4 to be commercialized as a hot-rolled steel strip coil. At this time, depending on the rolling state, the reduction amount in the width direction of the steel sheet S may become uneven, causing partial elongation, which is one of the causes of defective shapes of the steel sheet S.

[0004] For example, when the edge portion (widthwise end portion) of a steel sheet is stretched more than the center portion (widthwise center portion), the edge portion will have a wavy shape. Conversely, when the center portion is stretched more, the center portion will have a wavy shape. Such shape defects not only result in a defective product, but also deteriorate the sheet passing properties in the next process such as pickling and cold rolling, causing operational troubles. Therefore, there is a strong demand to prevent shape defects from occurring in hot-rolled steel sheets.

[0005] However, it is difficult to accurately measure the shape of a steel plate, and there are many cases in which accurate measurement cannot be performed due to disturbances such as meandering, jumping, and waving during rolling of the steel plate.

[0006] As a technique for measuring the shape of a steel sheet immediately after the delivery side of finish rolling, various techniques have been proposed in the past, such as a method using a rod-shaped light source or a magnetic sensor. Among them, Patent Documents 1 to 3, for example, disclose a particularly effective technique in which a point-like or linear light beam is irradiated onto a target surface using a laser, and the shape of the steel sheet is measured by measuring the reflected light.

[0007] Furthermore, Patent Document 4 discloses a technology for a laser irradiation method that uses three line lasers whose longitudinal direction is perpendicular to the conveying direction of the steel plate. In the technology disclosed in Patent Document 4, a line laser is irradiated in parallel to the longitudinal direction of the steel plate so as to form three equally spaced lines, and the reflected images are acquired and the profiles of each laser are compared to remove the effects of vertical vibration of the steel plate.

[0008] Furthermore, Patent Documents 5 to 7 disclose technologies for stably measuring the shape of a target surface regardless of the specularity or the inclination of the target by increasing the number of lines irradiated more cheaply than by using a laser, by using a powerful LED light source to irradiate the target surface with a stripe pattern consisting of multiple lines.

[0009] At present, the method for measuring the shape of a steel plate that is widely used in hot rolling is the technology disclosed in Patent Document 8, which uses a laser rangefinder to measure the inclination of the steel plate, and converts the inclination into the wavelength of the steel plate to calculate the elongation of the steel plate. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Unexamined Patent Publication No. 56-124006 [Patent Document 2] Japanese Patent Application Publication No. 55-40924 [Patent Document 3] Japanese Patent Application Publication No. 58-11708 [Patent Document 4] Japanese Patent Publication No. 61-40503 [Patent Document 5] JP 2008-58036 A [Patent Document 6] JP 2011-99821 A [Patent Document 7] JP 2016-65863 A [Patent Document 8] Japanese Patent Application Publication No. 8-29147 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the conventional technology has the following problems. The techniques disclosed in Patent Documents 1 to 7 are all methods for measuring the shape of a target object by irradiating light onto a hot-rolled steel sheet using a light source and capturing the reflected light with a camera. However, considering the effects of high temperatures due to radiant heat, and the adhesion of steam, dust, oil, etc. to the steel sheet, advanced technology is required to measure stably for a long period of time with a light source or sensor close to the steel sheet being transported, and the maintenance costs are also high. In addition, since the shape measurement is performed in a relatively narrow field of view, it is difficult to distinguish between waves other than shape defects such as waving of the steel sheet and waves due to shape defects. Next, there is a problem that the shape cannot be measured stably because it is easily affected by meandering of the steel sheet.

[0012] The technology disclosed in Patent Document 8 uses a distance meter to calculate the elongation of a steel sheet and measure its shape, but like the technologies in Patent Documents 1 to 7, it is heavily affected by waving and meandering of the steel sheet. There are also problems with these measurement methods, such as incorrect judgments when determining whether the shape is good or bad, and causing sheet threading defects in the next pickling process or cold rolling process. To prevent this, it is possible to move the light source away from the target, but the light will diffuse and the amount of light will decrease, making it difficult to design an optical system that stably collects light to ensure the amount of light. With the distance meter method, even if measures such as moving the light source away from the target are taken, the field of view does not change, so it is difficult to improve these problems.

[0013] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a shape measurement method, quality control method, and manufacturing method for a strip-shaped substrate, which can easily and stably determine the shape of the surface of the strip-shaped substrate and also reduce maintenance costs, as well as a shape measurement device and manufacturing equipment for the strip-shaped substrate. [Means for solving the problem]

[0014] The shape measurement method of a strip-shaped substrate of the present invention, which advantageously solves the above-mentioned problem, is a method for measuring the shape of a strip-shaped substrate, and is characterized in that it includes an imaging step of capturing images of both sides of the strip-shaped substrate, an image processing step of calculating a shape index of the strip-shaped substrate from the obtained images, and a judgment step of judging the quality of the shape of the strip-shaped substrate based on the obtained shape index.

[0015] The shape measuring method of the belt-shaped substrate according to the present invention is as follows: (a) in the image processing step, a plurality of images overlapping in the width direction and the length direction of the strip-shaped substrate are connected, and then a displacement amount at both ends and a center in the width direction of the strip-shaped substrate is calculated, a predetermined region of the strip-shaped substrate is extracted, a plurality of divided sections are set by dividing the strip-shaped substrate in the width direction and the length direction, and the shape index is calculated using a luminance distribution and a luminance standard deviation of a plurality of pixels in each divided section; (b) in the judging step, the quality of the shape of the belt-shaped base material in the longitudinal direction is judged from the shape index of each divided section according to a predetermined judgment criterion for the shape index; This may be a more preferable solution.

[0016] The quality control method for a strip-shaped substrate of the present invention, which advantageously solves the above-mentioned problem, is characterized by using any of the above-mentioned methods for measuring the shape of a strip-shaped substrate, and cutting and removing any section of the strip-shaped substrate in the longitudinal direction that is determined to have a poor shape.

[0017] The manufacturing method of a strip-shaped substrate of the present invention, which advantageously solves the above-mentioned problem, is characterized in that it uses any of the above-mentioned methods for measuring the shape of a strip-shaped substrate, and changes the manufacturing specifications of the strip-shaped substrate so that the obtained shape index falls within a predetermined range of a specified shape index.

[0018] In addition, the manufacturing method of the strip-shaped base material according to the present invention may more preferably be solved in such a manner that the strip-shaped base material is a steel strip and the manufacturing specifications are rolling conditions.

[0019] The shape measuring device for a strip-shaped substrate of the present invention, which advantageously solves the above-mentioned problems, is an apparatus for measuring the shape of a strip-shaped substrate while it is being transported, and is characterized in that it comprises an imaging means for continuously capturing images of both sides of the strip-shaped substrate, an image processing means for calculating a shape index of the strip-shaped substrate from the obtained images, and a judgment means for judging the quality of the shape of the strip-shaped substrate based on the obtained shape index.

[0020] The shape measuring device for a belt-shaped substrate according to the present invention is (c) the image processing means has a function of connecting a plurality of overlapping images of the strip-shaped substrate in the width direction and the length direction, calculating the amount of displacement at both ends and the center in the width direction of the strip-shaped substrate, extracting a predetermined region of the strip-shaped substrate, setting a plurality of divided sections divided in the width direction and the length direction, and calculating the shape index using the brightness distribution and brightness standard deviation of a plurality of pixels in each divided section; (d) the judgment means has a function of judging whether the shape of the belt-shaped base material in the longitudinal direction is good or bad from the shape index of each divided section in accordance with a predetermined judgment standard for the shape index; This may be a more preferable solution.

[0021] The manufacturing equipment for strip-shaped substrates of the present invention, which advantageously solves the above-mentioned problems, is characterized in that it comprises one or both of a shape measuring device for strip-shaped substrates of any of the above-mentioned types, a means for cutting and removing sections whose shape is determined to be poor using the obtained shape index or the judgment result of whether the shape is good or bad, and a control means for changing the manufacturing specifications of the strip-shaped substrates so that the obtained shape index falls within a predetermined range of a specified shape index. Effect of the Invention

[0022] According to the present invention, the surface of a strip-shaped substrate can be easily and stably operated, and the imaging device of the shape measuring device itself can be used in combination with a surface defect detection device, so maintenance costs can be reduced. Furthermore, since the method covers a wide field of view and targets the entire width of the strip-shaped substrate, it is possible to calculate the shape index without being affected by the meandering of the strip-shaped substrate. The present invention can also solve the waving phenomenon of strip-shaped substrates. For example, the wavelength of waving is several tens of meters, but the wavelength due to shape defects such as one-sided extension and anti-belt extension is about 600 mm, so if the shape index is calculated from the standard deviation of brightness every 1 m in the longitudinal direction, the shape can be determined without being affected by waving. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic perspective view showing a configuration in which a shape measuring device for a belt-shaped substrate according to an embodiment of the present invention is disposed in a production line for a belt-shaped substrate. [Diagram 2] 2A and 2B are enlarged schematic views of the shape measuring device for a belt-shaped substrate according to the embodiment, in which (a) is a schematic side view and (b) is a schematic front view. [Diagram 3] FIG. 4 is a diagram showing an example of an image of the surface of a belt-shaped substrate. [Figure 4]FIG. 11 is a flow chart illustrating each step of a shape measurement method for a strip-shaped substrate according to another embodiment of the present invention, where (a) shows an imaging step, (b) shows an example of an image processing step, and (c) shows an example of a shape determination step. [Diagram 5] 5 is a schematic diagram showing an overview of image processing steps in the shape measurement method, in which (a) shows an example of an image to be processed, (b) shows a method for setting division sections, and (c) shows an example of an image of the division sections. [Figure 6] 13 is an example of calculating the luminance distribution in one divided section, where (a) shows an image of the target divided section, and (b) is a graph showing the calculated luminance distribution. [Figure 7] FIG. 11 is a schematic diagram for explaining how to determine shape defects at the tail end of a steel plate, in which (a) shows an example image of a target section, (b) is a graph showing the standard deviation of brightness in a divided section, and (c) is a graph for determining shape defects from the longitudinal progression of the shape index. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the embodiments of the present invention will be described in detail. Note that the drawings are schematic and may differ from the actual ones. Furthermore, the following embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and are not intended to limit the configuration to the following. In other words, the technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0025] (Shape measuring device for belt-shaped substrate) Fig. 1 shows an example of a shape measuring device arranged in a production line for hot-rolled steel sheets as a strip-shaped substrate manufacturing device. In hot rolling equipment 1, steel sheet S is finish-rolled in a finishing rolling mill row 2, passes through a cooling zone 2 where laminar cooling is performed, and is wound into a hot-rolled steel strip coil by a coiler 4. In the example of Fig. 1, a shape measuring device 3 that also serves as a surface inspection is attached downstream of the cooling zone 2 in the steel sheet conveying direction PL. The shape measuring device for strip-shaped substrate is suitable for use in equipment that conveys strip-shaped substrates, such as cold rolling equipment, annealing equipment, and strip-shaped substrate straightening equipment.

[0026] FIG. 2(a) is a schematic enlarged side view showing the arrangement of the shape measuring device 3 in the hot rolling equipment. FIG. 2(b) is a schematic front view of the same viewed in the conveying direction PL of the steel sheet S. Table 1 shows an example of specification information for the shape measuring device of the above embodiment. In the example of FIG. 2, the upper surface of the steel sheet S is measured by the upper surface side shape measuring device 3A, and the lower surface of the steel sheet S is measured by the lower surface side shape measuring device 3B. As imaging means for both the upper surface and the lower surface, seven two-dimensional area CCD cameras 3A1, 3B1 and three strobe lights 3A2, 3B2 are arranged in the width direction and installed. The area CCD cameras 3A1, 3B1 are arranged so that the entire width of the steel sheet S can be imaged while overlapping the field of view in the width direction. The strobe lights 3A2, 3B2 face inward so that the optical axes of the lights on both sides intersect each other. The optical axis of the area CCD cameras 3A1, 3B1 and the optical axis of the strobe lights 3A2, 3B2 are inclined so that they intersect on the steel sheet surface in a side view. The optical axis CA of the area CCD cameras 3A1, 3B1 and the optical axis LA of the strobe lights 3A2, 3B2 are preferably not in the position of regular reflection, and are preferably inclined to the same side with respect to a vertical plane perpendicular to the steel sheet S surface and the conveying direction PL. It is preferable that both optical axes CA and LA are inclined to the upstream side in the steel sheet conveying direction PL, and the optical axis LA of the lights is inclined more than the optical axis CA of the camera. On the lower surface side, in order to secure a field of view, a gate 6A is provided by partially removing the conveying roll 6 and opening only when imaging. It is preferable to provide a draining means (not shown) upstream of the shape measuring device 3A on the upper surface side. Examples of the draining means include a high-speed water spray and an air compressor.

[0027] [Table 1]

[0028] The captured images are accumulated, for example, as a result of strobe illumination and photography 50 to 200 times per second, while synchronizing seven cameras in each direction of the width of the steel sheet S. It is preferable to capture images about 100 times per second. Figure 3 shows a combination of multiple captured images, with overlapping parts taken into consideration. The images are arranged in the conveying direction PL of the steel sheet from the leading end LE to the trailing end TE, and a portion of the section at the trailing end TE is shown.

[0029] The shape measuring device 3 includes, in addition to the imaging means, an image analysis means for analyzing the captured image and a judgment means for judging the quality of the shape of the steel sheet, for example, a computer (not shown). The shape measuring device 3 may be connected to, for example, a host computer (calculator) that manages the rolling equipment, and transmit the judgment result of the steel sheet shape.

[0030] (Method for measuring the shape of a belt-shaped substrate) 4 is a flow diagram illustrating a method for measuring the shape of a strip-shaped substrate using the above-mentioned strip-shaped substrate shape measuring device. In this embodiment, the method includes an imaging step (FIG. 4(a)), an image processing step (FIG. 4(b)), and a judgment step (FIG. 4(c)) for judging whether the shape of the strip-shaped substrate is good or bad.

[0031] FIG. 4 shows a method for measuring the shape of a steel sheet when the hot-rolled steel sheet is produced using the hot rolling equipment of FIG. First, before starting the imaging step (S10), steel plate information is acquired (S11). The acquired steel plate information includes manufacturing specifications such as steel plate standard, plate thickness, plate width, total length, total weight, and component composition, as well as operating conditions such as rolling conditions of each rolling mill, measured plate width, and conveying speed. Next, when the leading edge (LE) of the steel plate reaches the imaging position of the shape measuring device 3, continuous imaging is started while strobe-illuminating the images of the upper and lower surfaces of the steel plate S (S12). When the tail end (TE) of the steel plate passes the imaging position of the shape measuring device 3, imaging is stopped (S13). Then, the captured image of the predetermined section is stored (S14), and the imaging step is terminated (S15). In the example of Fig. 4(a), the image of the section from the tip end side 100 m to the tail end side 100 m is stored as the predetermined longitudinal length L1.

[0032] Next, the image processing step is started (S20). Figure 5 shows an overview of the image processing step. As shown in Figure 5(a), the edge portion of the steel plate S is detected from the obtained image of a predetermined section (S21). The edge EDR of the prime mover side DR and the edge EOP of the operator side OP are detected. Next, the center line CL in the width direction of the steel plate S is drawn based on the detected edges, and the central displacement amount is calculated. The obtained image is then equally divided in the width direction (S23), as shown in an example in FIG. 5(b). In FIG. 5(b), the total width W of the steel plate S is divided into seven parts into a length of W / 7, but the number of divisions is arbitrary. Taking into consideration the accuracy of analysis and the complexity of calculations, the number of divisions in the width direction is preferably 5 to 10. Then, the longitudinal length L1 to be analyzed is equally divided (S24). In the example of FIG. 5(b), the section of L1=100m is divided into 100 sections, each 1m long. An example image of the divided sections is shown in FIG. 5(c). By dividing the longitudinal section into sections of about 1m, shape defects such as one-sided elongation and anti-body elongation can be detected without being affected by long-wavelength waving. Next, the image is analyzed for each divided section, and the luminance distribution is calculated (S25). An example of the luminance distribution is shown in FIG. 6. The divided section in FIG. 6(a) has 546 pixels, and the unit of luminance is 256 grayscale levels. FIG. 6(b) is a graph in which the number of pixels for each luminance is plotted on the vertical axis. The standard deviation of luminance is calculated as a shape index from the luminance distribution of each divided section (S26). Then, the image analysis step ends (S27). Here, the number of pixels and the number of luminance levels are arbitrary, but it is preferable to determine them taking into consideration the analysis accuracy and calculation time.

[0033] Then, the step of determining the steel plate shape is started (S30). First, a luminance standard deviation threshold value for determining whether the shape is good or bad is obtained for each steel sheet standard obtained in step S11 (S31). For example, the luminance standard deviation threshold value may be determined based on past manufacturing results, for example, the relationship between shape defects and operational troubles. Next, the luminance standard deviation of each divided section obtained in the image analysis step is subjected to moving average processing in any section in the longitudinal direction (S32). Next, for example, a section starting from the tail end side TE until the moving average brightness standard deviation in the conveying direction PL falls below the acquired threshold is calculated (S33). Then, the section from the tail end side TE until the brightness standard deviation falls below the acquired threshold is transmitted to the host computer as a shape defect section (S34). Then, the determination step is terminated (S35).

[0034] An outline of the judgment step is illustrated in FIG. 7. The image in FIG. 7(a) was analyzed, and the brightness standard deviation of each divided section is shown in FIG. 7(b) in a graph. The moving average in the longitudinal direction was calculated by 5-point average using OP2 and DR2 (see FIG. 5(b)) including 1 / 4 in the width direction, and was determined as AOP and ADR. FIG. 5(c) is a graph showing the sum of the moving average AOP and ADR as "OP2+DR2" and the difference as "OP2-DR2". As is clear from FIG. 7(a), the operator side OP of the steel plate is extended at the tail end side TE, and is wavy, and the brightness standard deviation on the operator side is large. In this example, the degree of shape defect was judged when the shape index "OP2-DR2" was below the threshold value of 30. Then, 17 m from the tail end side TE was determined as the shape defect section with one-sided extension. The threshold value of the shape index can be changed from 10 to 50 depending on the tolerance of the steel strip threading in the next process, and is preferably 20 to 40.

[0035] The quality control method for the strip substrate according to the present embodiment further includes a step of cutting and removing a section determined to have a defective shape in the longitudinal direction of the strip substrate using the above-mentioned strip substrate shape measurement method. For example, based on the defective shape section transmitted to the upper computer in the above-mentioned determination step, a shearing device is operated in a finishing line to cut and remove a predetermined length of the defective shape section from the tail end side TE. By doing so, for example, when the tail end side TE of the preceding material and the front end side LE of the succeeding material are joined and continuously rolled in the cold rolling equipment of the next process, it is possible to suppress the steel sheet S from meandering due to the defective shape, and the edge colliding with the guide, causing defects or damage to the equipment.

[0036] The manufacturing method of a strip-shaped substrate in this embodiment includes a step of using the above-mentioned method for measuring the shape of a strip-shaped substrate and changing the manufacturing specifications of the strip-shaped substrate so that the obtained shape index falls within a predetermined range of a specified shape index. For example, if the shape defect is a one-sided elongation, the rolling force of the prime mover side DR and the operator side OP of a certain rolling mill of the hot rolling mill is changed. Also, if the shape defect is an elongation of the width direction center, so-called belly elongation, it is possible to change the effect of the roll crown by shifting the work roll of the hot rolling mill in the axial direction. [Industrial Applicability]

[0037] The method and apparatus of the present invention enable easy and stable operation of determining the shape of the surface of a strip-shaped substrate and reduce maintenance costs, thereby contributing to improved productivity and being industrially useful. [Explanation of symbols]

[0038] 100 Hot rolling equipment 1 Finishing Rolling Mill Line 2. Cooling Zone 3. Shape measuring device (surface inspection device) 3A (Top side) Shape measuring device 3A1 Area CCD camera 3A2 Strobe Lighting 3B (Bottom side) Shape measuring device 3B1 Area CCD camera 3B2 Strobe Lighting 3C Gate 4. Koira 6 Transport roll 6A Gate S Steel plate (strip-shaped substrate) PL Steel plate conveying direction (pass line) LE tip side TE caudal side DR Prime Mover Side OP operator side CA (area CCD camera) optical axis LA (strobe lighting) optical axis EDR (motor side of steel plate) edge EOP (operator side of plate) edge CL (Steel plate width direction) center line L1 (Longitudinal length to be analyzed)

Claims

1. A method for measuring the shape of a belt-shaped substrate, comprising the steps of: An imaging step of capturing images of both sides of the belt-shaped substrate; an image processing step of calculating a shape index of the belt-shaped substrate from the obtained image; A judging step of judging whether the shape of the belt-shaped base material is good or bad based on the obtained shape index; A method for measuring the shape of a belt-shaped substrate, comprising:

2. In the image processing step, A plurality of images overlapping in the width direction and the length direction of the belt-shaped substrate are connected, and then the displacement amounts of both ends and the center in the width direction of the belt-shaped substrate are calculated; A predetermined region of the belt-shaped base material is extracted, and a plurality of divided sections are set by dividing the region in the width direction and the length direction; The method for measuring the shape of a belt-shaped substrate according to claim 1 , wherein the shape index is calculated using a luminance distribution and a luminance standard deviation of a plurality of pixels in each divided section.

3. In the determination step, 3. The method for measuring the shape of a strip-shaped substrate according to claim 1, further comprising judging whether the shape of the strip-shaped substrate in the longitudinal direction is good or bad from the shape index of each divided section in accordance with a predetermined criterion for judging the shape index.

4. A quality control method for a strip-shaped substrate, comprising: using the shape measurement method for a strip-shaped substrate according to any one of claims 1 to 3; and cutting and removing a section of the strip-shaped substrate in the longitudinal direction that is determined to have a defective shape.

5. A method for manufacturing a strip-shaped substrate, comprising: using the shape measurement method for a strip-shaped substrate according to any one of claims 1 to 3; and changing manufacturing specifications of the strip-shaped substrate so that the obtained shape index falls within a predetermined range of a predetermined shape index.

6. The method for producing a strip-shaped substrate according to claim 5, wherein the strip-shaped substrate is a steel strip, and the production specifications are rolling conditions.

7. An apparatus for measuring the shape of a belt-shaped substrate during transportation, comprising: An imaging means for continuously capturing images of both sides of the belt-shaped substrate; an image processing means for calculating a shape index of the belt-shaped substrate from the obtained image; A judgment means for judging the shape quality of the belt-shaped base material based on the obtained shape index; A shape measuring device for a belt-shaped substrate comprising:

8. The image processing means includes: A plurality of images overlapping in the width direction and the length direction of the belt-shaped substrate are connected, and the displacement amounts of both ends and the center in the width direction of the belt-shaped substrate are calculated; A predetermined region of the belt-shaped base material is extracted, and a plurality of divided sections are set by dividing the region in the width direction and the length direction; A function of calculating the shape index using a luminance distribution and a luminance standard deviation of a plurality of pixels in each divided section. The shape measuring device for a belt-shaped substrate according to claim 7.

9. The determination means is A function of judging whether the shape of the belt-shaped base material in the longitudinal direction is good or bad from the shape index of each divided section according to a predetermined shape index judgment criterion; The shape measuring device for a belt-shaped substrate according to claim 7 or 8.

10. The shape measuring device for a belt-shaped substrate according to any one of claims 7 to 9, A manufacturing facility for a strip-shaped substrate comprising either or both of a means for cutting and removing sections whose shape is judged to be poor using the obtained shape index or the judgment result of whether the shape is good or bad, and a control means for changing the manufacturing specifications of the strip-shaped substrate so that the obtained shape index falls within a predetermined range of a specified shape index.

Images