JPH0220922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material thickness correction method for accurately correcting the apparent thickness of a corrugated portion of a steel plate when measuring the thickness in a steel plate manufacturing process.

The thickness of a cold-rolled steel plate affects processing accuracy and workability during use, and is also important for ensuring the strength of finished parts, so it is necessary to accurately understand it. Thickness can be measured using a micrometer from around the steel plate, but this method cannot be used to measure the thickness of steel plates that are continuously running on processing lines such as cold rolling mills, so generally X-rays and γ-rays are used to measure the thickness. , thickness gauges that utilize laser beams or micro waves are used to continuously measure plate thickness.

When measuring by these methods, the thickness is generally detected in a vertical direction from the bottom to the top of the steel plate, such as transmission thickness measurement using gamma rays. However, no part of the steel plate itself is threaded in a completely horizontal state, and as shown in Fig. 1, which is somewhat exaggerated, Material 1 is often threaded with a wavy state. . In the conventional detection means, the inclined portion due to the undulation is also measured from the vertical direction, so that even though the true thickness of the material 1 is T as shown in FIG. The apparent thickness t of the sample was detected, which resulted in a drawback that the measurement results lacked reliability.

The purpose of the present invention is to eliminate this type of drawback in conventional plate thickness measuring means, to provide a material plate thickness correction method that can accurately capture the true plate thickness even in corrugated areas, and to provide reliable plate thickness measurement. It is about improving sexuality.

The main focus of the method of the present invention is to process the slope of the material into a high-resolution image using an industrial video camera installed on the side of the steel plate, and capture the slope angle from the coordinates of the pixel.
The apparent thickness detection value is corrected using this inclination angle to obtain the true thickness, and the feature is that a correction line is provided separately from the conventional transmission type thickness measurement line.

As shown in Fig. 1, a thickness measurement line 2 similar to the conventional measurement method using a thickness gauge 21 such as an X-ray thickness gauge or a γ-ray thickness gauge is provided at the measurement point to detect the apparent thickness t of the material 1. let

On the other hand, a correction line 3 is provided with an industrial video camera 31 that is directed from the side of the steel plate in the width direction of the steel plate, and the measurement points measured by the thickness gauge 21 are instantaneously photographed from the side. A high-quality image processor is used to capture the inclined portion in the side cross-sectional direction of the material 1 and perform image processing as shown in FIG.

The image has a pixel unit, and predetermined reading points P ₁ and P ₂ are set on both sides of the reference point R, which is the transmission thickness measurement position, respectively, and the inclination coordinates x ₁ and y ₁ of the material at each reading point are determined. : Read x ₂ , y ₂ . Next, a calculation device is used to calculate the tilt angle θ at the reference point R from the tilt coordinates of each reading point P ₁ and P ₂ . That is, tanθ=y ₂ −y ₁ /x ₂ −x ₁ θ=tan ⁻¹ y ₂ −y ₁ /x ₂ −x ₁ The contents of the calculation are as follows: cos θ is finally determined and used as a correction value, and the apparent thickness t already measured at thickness measurement line 2 is multiplied by the correction value cos θ to obtain the true thickness T (see FIG. 2).

T=t·cosθ The obtained corrected thickness T is displayed and recorded by a display and a recorder as necessary.

In the above process, when image processing is performed on the image taken by the camera 31, if the resolution is increased, |x ₂ −x ₁
Since | can be made small, the inclination angle θ of the tangent at the reference point R can be measured with high accuracy, and the correction accuracy can be improved.

According to the method of the present invention, regardless of the degree of waviness of the material to be threaded, the inclination state of the measuring section is accurately captured and corrected, so that accurate board thickness can always be detected. For example, by measuring the plate thickness in a hot tandem rolling machine, or by measuring the thickness of the entire length of the steel plate being rolled before and after the thick plate rolling machine, including the tip and rear nose sections, the reduction in rolling in the next stage of rolling can be corrected. This makes it possible to significantly improve rolling precision. Furthermore, it can be easily applied to other existing measurement lines to improve measurement reliability.

[Brief explanation of drawings]

Figure 1 is a flow chart of the method of the present invention. FIG. 2 is a sketch of an image of a measuring section processed based on the method of the present invention. FIG. 3 is an explanatory view diagrammatically showing the tilting state in the measuring section. 1: Material, 2: Thickness measurement line, 3: Correction line.

Claims (1)

[Claims] 1. In a corrugated material plate thickness correction method in transmission type thickness measurement of a steel plate, the apparent thickness t at the material measurement point is obtained by a thickness gauge, and the corrugated state of the material at the measurement point is provided on the side of the steel plate. Capturing it as an image on an industrial video camera and reading the inclination coordinates (x ₁ , y ₁ : x ₂ , y ₂ ) of the longitudinal section of the material from this image; calculating the inclination angle θ and cos θ of the material from the inclination coordinates; A material plate thickness correction method comprising calculating a correction value by multiplying the apparent thickness t by cos θ, and displaying and recording the corrected true thickness T.