JPH07306162A - Flaw detecting device - Google Patents

Abstract

PURPOSE:To provide a flaw detecting device which can be operated easily, can shorten inspecting time, and can improve inspection precision and, at the same time, can discriminate flaws from spots formed of adhering foreign matters. CONSTITUTION:A flaw detecting device is constituted of an illuminating device which illuminates the surface of an object (W) to be inspected, a single or plurality of photographing devices (CM) which take the picture of the illuminated surface of the object, and display device (DP) which is installed separately from the photographing devices and displays the picture of the surface of the object (W) taken by the photographing devices (CM). The illuminating device is provided with a plurality of lighting equipment (L1-L5) which can illuminate the surface of the object (W) from different directions in accordance with commands sent from a distant place.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flaw inspection apparatus used for inspecting the presence or absence of flaws or the size of flaws generated on the surface of an object such as a rolled steel plate.

[0002]

2. Description of the Related Art Conventionally, visual inspections such as the presence or absence of flaws and their sizes that occur on the surface of objects such as rolled steel sheets have been conducted at manufacturing sites.
Since it is in a bad environment due to high temperature etc., a lighting device and a shooting device such as a TV camera are installed in the site, and the image is displayed on a display device installed in an inspection room with a good remote environment for visual inspection. A remote inspection system that performs inspection has been developed. Further, as disclosed in JP-A-3-118451, irradiating the inner surface of the cylindrical body with light through an optical fiber, converting the reflected light into an electric signal, and comparing the electric signal with a reference value. There is also known an inspection device that automatically inspects for stains due to the presence of flaws and the attachment of dust.

In the above-described conventional flaw inspection apparatus, since the positional relationship between the illumination device and the photographing device is fixed, it may be difficult to identify the flaw depending on the position, direction and shape of the flaw to be inspected. When the inspector changes the direction of observation depending on the situation when performing visual inspection at the site,
In the case of remote inspection, it seems that the position of the imaging device should be changed according to the situation. However, changing the position of the imaging device changes the distance to the object to be photographed, so focusing must be performed in conjunction with the change in position, which complicates the operation and prolongs the inspection time. is there. Therefore, one object of the present invention is to provide a flaw inspection apparatus capable of reducing the inspection time and improving the inspection accuracy by a simple operation.

Further, as suggested by the above patent publication, since it is difficult to distinguish between flaws and stains, stains that can be removed by the cleaning process are excluded and only the presence or absence of flaws and the shape are inspected. Is generally difficult. Therefore, another object of the present invention is to provide a flaw inspection apparatus capable of inspecting only flaws by distinguishing them from stains caused by dust adhesion.

[0005]

An illumination device for illuminating a surface of an object to be inspected, a single or a plurality of image capturing devices for capturing an image of a surface of an illuminated object, and a device installed separately from the image capturing device. And a display device for displaying an image of the surface of the object photographed by the photographing device. The illuminating device includes a plurality of luminaires capable of illuminating the surface of the object to be inspected from different directions according to commands issued at distant locations.

[0006]

Function: The flaw generally has an irregular three-dimensional shape. Therefore, by changing the direction of the illumination so as to be optimal for visual inspection according to the shape of each flaw, the presence or shape of the flaw can be identified with high accuracy. In addition, the flaw has an irregular three-dimensional shape, and the position and size of the shadow vary depending on the direction of the illumination. For this reason, it is possible to easily discriminate from a planar foreign matter such as oil stain depending on whether or not the shape of the image of the foreign matter including the shadow changes depending on the direction of the illumination.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the structure of a flaw inspection apparatus according to an embodiment of the present invention. Referring to FIG. 1 (A), an arcuate frame F is installed above a steel plate W to be inspected, which is conveyed by an appropriate conveying mechanism such as a roller. One projector L1
L5 is fixed downward. A television camera CM is fixed to an appropriate portion of the frame F in a state where the surface of the steel sheet to be inspected is in view. Furthermore,
A switchboard D for selectively supplying power to each of the five projectors is installed in accordance with a command from a command device installed remotely.

Referring to FIG. 1 (B), a control console CN is installed in an inspection room in a good environment away from the work site where the steel sheet W is transported, and the television receiver DP is installed on the control console. Is installed. Television receiver D
On P, an inspection image of the surface of the object, which is captured by the television camera CM installed at the site and is transferred through the coaxial cable CB1, is displayed. The illumination command input by operating the five push button switches SW installed on the control console CN is transferred to the switchboard D installed on site through the multi-core cable CB2.

A predetermined one of the five projectors L1 to L5 is selectively turned on in accordance with an illumination command transmitted from the console CN through the multi-core cable CB2 of the switchboard D. FIG. 1 exemplifies a state in which only the leftmost projector L1 is lit. Each of the five push-button switches SW installed on the control console CN is arranged corresponding to the arrangement of the five projectors L1 to L5 installed on the site, and is turned on by pressing down. Then, the lamp inside the plastic case lights up to indicate that it is in the on state. Therefore, the operator of the control console can easily and accurately grasp from which direction the surface of the steel sheet W to be inspected is illuminated by the arrangement of the push button switches SW and the individual lighting states. . Note that each push button switch SW shifts to the OFF state by being pressed again.

[0010] Preferably, the switchboard D controls the power supply state such as the power supply voltage to the lit floodlights so that the amount of light emitted from all the lit floodlights is almost always a constant value. .
For example, when two light projectors are on, the amount of light generated by each light projector is reduced to half the value when only one of the light projectors is on. As another method of controlling the power supply state, the previous power supply amount for each projector is stored as a ratio to the maximum power supply amount, and this is read every time the corresponding pushbutton switch is operated, and a new value is obtained. It is also possible to apply a method of resetting the power supply ratio, a method of storing the immediately previous power supply ratio manually adjusted, and resetting this as a new power supply ratio.

As shown in FIG. 1C, if a concave flaw exists on the surface of the steel plate W to be inspected, illumination from the left side is displayed on the display screen of the television receiver DP. The received bright flat part c and the brighter inclined part a
And a dark inclined portion b appear. In this case, control console C
When the right-end pushbutton switch SW on N is also pressed to turn on the right-end projector L5, the dark inclined portion b disappears from the foreign matter on the display screen and the bright inclined portion b appears instead. When the projector L1 at the left end is turned off by depressing the push button switch SW at the left end again, the bright inclined portion a disappears from the foreign matter being displayed, and the dark inclined portion a appears instead. In this way, the shape of the flaw can be accurately confirmed also by how the brightness of the foreign matter on the display screen changes due to the blinking of the projector.

If the concave flaw is also an irregular shape, the shape of the foreign matter including the shadow changes by changing the direction of illumination. If the foreign matter is a planar foreign matter such as oil stain, the shape hardly changes even if the direction of the illumination is changed. Therefore, it is possible to discriminate from a three-dimensional flaw. Such an advantage is an advantage that cannot be obtained only by changing the position of the photographing device.

FIG. 2 is a perspective view showing another arrangement example of the illumination device and the photographing device in another embodiment of the flaw inspection apparatus of the present invention. In this embodiment, a semi-annular frame G is installed above the object to be inspected, and five light projectors L1 to L5 are fixed to the frame G at substantially equal intervals. The television camera TC is installed on the line passing through the center of the frame G with the visual field right below. Each of the five projectors projects irradiation light with the center of the field of view of the television camera CM facing. With such a configuration, the direction of illumination can be changed not only right and left but also front and back, and the accuracy of inspection can be further improved.

In the above, the configuration has been illustrated in which the plurality of floodlights are blinked and the push button switches indicating the respective blinking states are installed on the control desk. However, such a push button switch can be realized by combining another appropriate switch and an indicator light, or such an indicator light can be provided above the display screen of the television receiver DP by the television camera C.
It is also possible to adopt a configuration in which it is combined with the M image pickup screen and displayed. Alternatively, in the embodiment of FIG. 1, as illustrated in FIG. 2, the direction of the currently selected illumination light may be combined with the imaging screen of the television camera CM and displayed by radial arrows.

The present invention has been described in the case where the operator visually inspects the photographed image. However, automatic identification is performed by adding a device that identifies the image of the surface of the captured object, and if a somewhat large flaw is identified, the operator is notified by a buzzer sound, etc. Specifically, it is possible to adopt a configuration in which an automatic inspection such as an operator's confirmation by visual inspection and a visual inspection are combined. In this case, under the automatic identification state, in addition to fixing the illumination state, the identification device may issue a command regarding illumination according to a predetermined identification algorithm.

Alternatively, the present invention can be applied to a case where only automatic identification is performed without performing visual inspection by an operator. In this case, the instruction regarding lighting is issued from the identification device according to a predetermined identification algorithm. Further, with this configuration, the automatic identification device can be installed at a transportation site where the environment is bad.

Further, although the configuration in which one image pickup device is installed has been exemplified, a configuration in which a plurality of image pickup devices are installed may be adopted.

[0018]

As described in detail above, since the flaw inspection apparatus of the present invention is configured to change the direction and combination of illuminations, it is possible to perform a simpler operation than changing the position of the photographing apparatus. With the above, there is an effect that a highly accurate inspection becomes possible.

There is also an advantage that it is possible to inspect a three-dimensional flaw while distinguishing it from a two-dimensional stain from the state of the shape change of the foreign matter including the shadow due to the change of the direction of the illumination.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a perspective view showing an example of arrangement of an illumination device and a photographing device in another embodiment of the present invention.

FIG. 3 is a diagram showing another example of the display screen in the embodiment of FIG.

[Explanation of symbols]

 L1 to L5 Floodlight (illuminator) D Switchboard CM Television camera (shooting device) DP Television receiver (display device) CN Control console SW Pushbutton switch that issues operation commands to the floodlight CB1, CB2 cable

Claims (6)

[Claims] 1. An illumination device for illuminating the surface of an object to be inspected, a single or a plurality of image capturing devices for capturing an image of the surface of an illuminated object, and an image capturing device that is installed apart from the image capturing device. In a flaw inspection device including a display device that displays an image of the surface of the object, a plurality of illuminating devices capable of illuminating the surface of the object to be inspected from different directions according to a command issued at a distant location. A flaw inspection device comprising a lighting fixture. 2. The lighting device according to claim 1, wherein the lighting fixtures are fixed at equal intervals to an annular frame installed above the object to be inspected in parallel with the object and directly below the center of the frame. A flaw inspection device characterized by illuminating the surface of an object with illumination light. 3. The illumination device and the photographing device according to claim 1, wherein the lighting device and the imaging device are installed in a manufacturing or processing site of an object to be inspected, and the display device is installed in an inspection room remote from the manufacturing or processing site. A flaw inspection device characterized in that 4. The flaw inspection apparatus according to claim 1, further comprising display means on the display device for combining the information on the different illumination directions with the image of the photographing device. 5. The flaw inspection apparatus according to claim 1, further comprising an identification device for identifying an image of a surface of an object imaged by the imaging device. 6. An illumination device for illuminating the surface of an object to be inspected, a photographing device for photographing the surface of the illuminated object, and an identification device for identifying an image of the surface of the object photographed by the photographing device. In the flaw inspection device provided, the illumination device includes a plurality of lighting devices capable of illuminating the surface of the object to be inspected from different directions according to a command issued from the identification device.