JPS6145914A - Detecting method of surface strain defect of mirror surface body - Google Patents

Abstract

PURPOSE:To detect a defect by irradiating an irregular reflecting plane plate provided in parallel to the surface of a mirror surface body to be detected and at right angles to the moving direction, and picking up an image of a boundary pattern in which a linear inverted image of a plane plate end side formed by reflected light is reflected on the body to be detected as a reflected virtual image. CONSTITUTION:A reflecting plate 2 is provided above a stainless cold rolled steel sheet (downward curvature) 1 as the body to be detected in horizontal motion and this reflecting plate 21 is lighted up by an illumination lamp 5 from a flank of the steel plate 1 or slantingly below. An image pattern 3 formed on the steel plate 1 through the reflecting plate 2 irradiated with illumination light 9 is picked up by a TV camera 4 and displayed on a TV monitor 10 having a cursor line 11 for determining a reference value. Further, strain size 15 displayed on the cursor line 17 is detected quantitatively by an electronic circuit and displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting and measuring distortion defects on the surface of a metal or the like having a mirror-finished surface.

As a conventional detection method, a laser beam scanning method is easily considered, but a method using a laser can be considered for detecting curvature distortion defects in a mirror-like test material. However, when using laser light, the mirrored surface to be inspected is
Regarding a reflecting curved surface that constantly changes three-dimensionally during movement, it is actually impossible to capture reflected light that is continuously and accurately averaged. The material to be inspected is scanned with laser light.
In the case of a continuous wave-like movement of a mirrored and irregular aspherical surface, it is possible to constantly capture and receive the reflected light, but if the sensor receives specularly reflected light at one point, the received light signal becomes saturated and detection measurement is difficult. Purpose not achieved.

The present invention has been made based on the above circumstances.

The principle and embodiments of the present invention will be explained below with reference to FIGS. 1, 2, 3, and 4.

In Figure 1, 1. is a polished stainless steel plate with a mirror finish as the material to be tested in the example. In this specification, it will be abbreviated as a polished steel sheet hereinafter. 2 in Fig. 1 and Fig. 2 shows a reflective plate with a rough surface and no gloss, in order to reflect the reflected image on a polished steel plate. In this specification, it is abbreviated as a reflection plate. Figure 1 shows how the downward warpage of a polished steel sheet is measured. In Fig. 1, a reflector plate 2 is placed in the space above the polished steel plate that is moving horizontally as shown in the figure.
．． This reflector plate 2. 5. Lighting from the side or diagonally downward of the polished steel plate 1°. illuminate by. 9 in the figure is lighting lamp 5. Shows more illumination light.

Illuminated reflector 2. If the image pattern of the reflector on the polished steel plate moving downward is shown in Figure 1, pattern 3 is reflected when the polished steel plate is in a downwardly warped deformed state. shows. Chain line 6 shown in FIG. indicates a virtual line of a normally normal flat plate.

Polished steel plate 1. A virtual image of the inverted pattern reflected on the top surface of the TV is captured by the TV left camera. The captured image in this case is displayed on a monitor image as shown in FIG.

On the monitor screen shown in FIG. 4, the base of the image distortion is displayed as a distortion dimension 15 as shown in FIG. 4 with respect to a cursor line 17 provided in advance.

In the case of the present invention, the illustrated distortion dimension 15 can be quantitatively detected and displayed by converting it into a digital signal using an electronic circuit.

The monitor diagram shown in FIG. 3 is a monitor diagram for measuring the dimensions of upward warpage, similar to FIG. 4.

If the test object is in a normal flat shape (flat state), Figure 3.
It goes without saying that the pattern matches the pattern of cursor lines 16 and 17 shown in FIG.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention. 1...Stainless steel polished steel plate (downward curvature) 2...Reflector 3...Reflector reflection pattern (downward curvature) 4...
TV left camera 5...Lighting light 6...Stainless steel polished steel plate plane reference line 7...Stainless steel polished steel plate (upward curvature) 8...Reflector reflection pattern (upward curvature) 9.
...Indicates illumination light. FIG. 3 shows monitor images obtained during the course of the experiment as shown in FIG. In FIG. 3, numeral 10 indicates a TV monitor, and numeral 11 indicates a cursor line for determining a reference value. Similarly, 16 indicates a cursor line for determining the reference value. 12 indicates the amount of distortion. Similarly, FIG. 4 also shows the current state of FIG. 1 in the form of a monitor. Figure 1

Claims (1)

[Scope of Claims] 1. A diffusely reflective flat plate of white or other color with linear edges is placed perpendicularly or at a constant angle to the upper space of the specular surface of the object to be inspected. Illumination light is applied to the diffusely reflective flat plate, which is installed at an angle parallel to the surface of the material to be inspected and at right angles to the direction of movement of the material to be inspected. A detection method characterized in that surface distortions and defects on a mirror-like test material can be detected by imaging a sharp boundary pattern that is reflected as a virtual image of an inverted image of a mirror-like test material on a mirror-like test material. 2. A patent claim that reflects a reflected virtual image pattern vertically or obliquely on the surface of a mirror-like metal, etc., photographs the reflected virtual image with a TV camera and sensor, and measures the amount of distortion and defects by image processing this photographed pattern. A method for detecting surface distortions and defects in mirror-like metal, etc., according to scope 1.