JPS63255647A - Method of inspecting moving metallic surface - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for inspecting the surface of moving metal, such as aluminum. The present invention is particularly useful for automatically detecting and inspecting flaws on the surface of moving objects. The present invention relates to a device for storing visible images of abrasives for use in cooking. Strobe illumination or electronic or mechanical projections are used to capture the moving surface in a static state, thereby obtaining an undistorted image of the surface properties.

BACKGROUND OF THE INVENTION Inspection of objects for defects using camera equipment was used in U.S. Pat. No. 3,230,305 by KendriCk et al. 11 to detect irregularities in
8 n r V, U.S. Pat. Used in Patent No. 4,063,282.

'/ama'Juch1'J U.S. Patent No. 1I, 4
49. B1ε3 uses illumination of the same type as YZ to identify irregularities on the object, and diagonal illumination is used to detect foreign matter on the surface of the object. Vertical illumination is used to detect defects by recognizing the shape of the pattern.

U.S. Patent No. 4.403,294 by 11amada@
The issue also discloses recognition of irregular patterns, in which case the image signal is quantified as a binary = 1-code and then compared with a predetermined reference pattern to determine whether it is a visible image or contains a defective pattern. is determined.

U.S. Pat. No. 3,389,789 to Watson discloses a detector that determines whether an object is rejected when the magnitude of the video signal exceeds a threshold level of the detector, and U.S. Pat. ,3
No. 79,829 discloses a scratch detection device that selectively inspects scratches in a selected part of a glass product and ignores other parts.

U.S. Pat. No. 3,868,478 to 2eenkov also discloses an inspection device for use with moving objects, such as mail, in which an image of the addressee of a letter is captured using a flashlight. It is captured by a camera device, sent to a preview storage device, and displayed on a closed-circuit television monitor.

U.S. Patent No. 4.253,11 by Decave 1 et al.
No. 3 also uses a pre-vision monitor camera to monitor defects in the moving sheet.

U.S. Patent No. 4.377.74 to Kopineck et al.
No. 6, an optical image of the moving sheet is stored and used for later observation, and in U.S. Pat. No. 4,223,346 by Ne1hOiSe1 et al. Heavy coupling arrays and lenses are used between the cameras that extend the length in the direction of movement, but not the width of the field of view. Ohsumi et al., U.S. Pat. No. 4,219,844, detects gouges in a glowing slab by adjusting the illumination to produce reflected light with much greater energy than the radiant energy from the metal parts. .

Although numerous defect detection devices have been provided by the prior art, there remains an unmet need for inspection devices for moving aluminum surfaces presented by casting, rolling, extrusion, and other operations associated with the manufacture of aluminum products. The requirement addresses defect detection based on a comparison of the image pattern with a reference pattern using a specific illumination technique. - If the image containing the difference is automatically transmitted and viewed or processed electronically.

Means for Solving Problem C) In the present invention, a wide surface of a metal surface moving at a high speed is continuously and automatically lubricated, and a predetermined allowable surface condition f is applied.
A surface change exceeding 1 is detected and analyzed to determine the presence of a surface defect that should be rejected, and to determine the correctness of the defect.
A method is provided for classifying visible and non-visible reflections within a selected wavelength range to enhance surface features on said moving surface and thereby facilitate detection of surface defects. uniformly irradiating the moving surface with at least -h of reflected and diffused electromagnetic radiation;
momentarily immobilizing a rapidly moving surface and detecting the presence of one or more rejectable defects by means of a plurality of sensors arranged to view the entire width of the material; detecting and providing an electronic image of the area containing the defect containing gray scale levels representing varying intensity of electromagnetic energy reflected by the defect for subsequent display and analysis. transmitting from one or more of said sensors to an image storage device for the purpose of providing a range of grayscale levels representative of a range of foul electromagnetic energy intensities from a non-defective surface to be rejected; , comparing the grayscale level of said image having defects with a range of grayscale levels representing a surface without defects to be rejected; viewing and analyzing on a monitor only those surface images having gray scale levels outside the school range;

〔Example] The present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a portion of a moving metal sheet 10 is shown illuminated by a series of light sources 20, 30, 40, 50. Light sources 20 and 30 illuminate the surface of metal sheet 1-10 with diffused light, and light sources 40 and 5o illuminate metal sheet 10 with reflected light.

At this time, an image of the selected area of the illuminated metal sheet 10 is formed by one or more video cameras 60a to 60d, which transmit corresponding electrical signals to the respective biodetector 7Qa. or 7
Transmit to 0d. When an image containing one or more defects is detected by one or more -V detectors 70, a trigger signal is automatically sent to video storage 1i 180. The device 80 has one for each detector 70.
It includes a plurality of storage devices, one for each. That particular image may be stored in video storage 80 and later analyzed electronically or visually viewed on standstill monitor 90.

By means of the monitor 90, the scanner 90 can see the actual presence of the entire width of the seams 1 to 10 passing below the camera 60.
Any defect that should be rejected can be visually detected and quantified.

The classification of defect characteristics in the electronic evaluation is performed by the processing device 95.
It is carried out by This device is interfaced at 97 with a frame freeze monitor and also with a persistent storage device 100. Therefore,
Images stored in video storage 80 are further transmitted to persistent storage 100.

Storage device 100 includes a videotape, computer, laser disk, or other suitable storage device.

If desired, images of moving sea I~ can also be viewed in real-time mode, such as by monitor 66 shown in FIG. However, it should be recognized that at maximum production speeds, it is impossible to continuously perceive defects detectable by the detector 70 to the human eye.

In an embodiment of the invention, 10
The entire surface of the sea 1 is illuminated more uniformly by illumination of at least one of diffused light and reflected light. Diffuse lighting and Jsj DJ lighting in combination C can be used to highlight changes in the surface being inspected. In a particularly preferred embodiment, a long-wavelength non-I'iJ optical (infrared) spectrum that more fully matches the spectrum perceived by the imaging sensor used in a video camera is used. Illuminating the surface with partial light and enhancing the reflective properties of the surface.

A C1 person who is invisible is not disturbed by the high intensity strobe lighting process. The reflected or diffused energy from the illumination source 20, 30° 40.50 can be fixed or s1-robotic, depending on whether a shutter-type camera device is used. . Commercially available strobe light sources or camera shutters can capture moving surfaces at a rate of 60 times per second or multiples of 60 times per second. This typically means that if the field of view of camera 6o is 0.305 m (1 foot) (in the direction of movement toward sea 1), then 5
Inspection of 100% of the sheet surface moving at speeds of 1800 feet per minute or multiples thereof can be performed. In this case, the resolution of the image is 512 scan lines on the pre-vision screen, which is NTSC
It is based on the Pre-Vision broadcasting standard. To obtain an unblurred image of a moving surface, either the illumination source or the camera sensor must be strobed. This can be accomplished by using a pulsed VU illumination source or by using a mechanically shuttered camera sensor. In both cases, it is necessary to use a highly sclerotic illumination source.

Illuminated metal sheet 1 as shown in FIG.
The energy reflected from 0 is captured by one or more video camera devices 60 and converted to electronic signals and transmitted to respective detectors 70 . Video cameras suitable for implementing the present invention include RCA, GE, Pana
son ic.

It can be easily obtained manually from distributors such as 5ony and PhiIIips. The video detector used in the practice of the present invention was also manufactured by C0 Boulder, Colorado.
The device may be constructed from commercially available equipment such as the Model 630 Video Detector from IOradOVideo, InC0rpOrated.

In view of the width of the moving metal sheet, more than one camera can be used to monitor the entire area of the moving sea h. For example, in order to simultaneously inspect the entire width of a 48 inch (121.92 inch) wide metal sheet, four video camera devices are used, mounted side by side, as shown in Figure 1. The width of the pause is captured by the video storage device Z 80 and displayed on the stop monitor 90 .

The number of melas 6o required depends on the detail of the surface change to be detected. Optical magnification η provides the desired detail, but reduces the field of view of the camera.

The consequence is that if the field of view of the camera becomes smaller than the surface area to be monitored, more than one camera is needed.

The reflected images captured by video camera device 60 have varying intensities known in the art as gray scale levels. A particular grayscale level representative of a defect-free metal surface is determined experimentally, and one sample is used to plug the device, either without defects or with some type of known defect. Some defects absorb or scatter more light than a non-defect surface, and other defects absorb or scatter less light than a non-defect surface. The device is therefore standardized by defining both minimum and maximum grayscale levels that represent the range of intensity reflected from surfaces that are free of defects.

When an electronic signal, such as from a surface defect, provides a grayscale level outside the standardized range, the detector 70 detects this signal and activates the corresponding video device 80 to store the image. This is displayed on the monitor 90. The equipment used to accomplish this is of the current state of the art. The detection, storage, and display of images containing defects is therefore automatic without the need for visible manual intervention.

The stored image room is displayed on the monitor 90 so that visual inspection and investigation of this image for certain defects can determine whether or not a defect to be rejected actually exists. can be determined.

The image on monitor 90 remains there until other defects appear or until it is erased at will by the operator.

As mentioned above, the image of the defect is
Isk 100 J, Una, after sending it to a more durable storage medium? NEvaluated visually or electronically.
, the characteristics can also be determined by the device.

[Efficacy of excuse]

The present invention automatically monitors a moving surface, such as a moving metal sheet, detects defects on the surface, and records images of specific portions of the surface that identify the defects. 1 equipment and provide a reconsideration for visual and electronic determination of the defect characteristics to 1.1.

In this way, when a large number of materials are inspected at high speed by the eight machines, the operator first inspects the machine! lJ purchase has 4 defects. It is possible to further deeply observe 11 images of the moving object selected by i-4. Furthermore, by using at least one of reflected illumination 83 and diffuse illumination of selected wavelengths, the sensitivity of limb N to various types of defects is substantially increased.

[Brief explanation of drawings]

Figure 1 shows that the 7J payment of the present invention is actually 11I! A schematic diagram of a part of the detection device shown in FIG.
There are 1179 pictures. Jungetsu's explanation 10...Moving metal sheet, Boa~60d...Video camera, 66...
...Reful time monitor, 70a-70d...
・Video detector, 80...Video A storage device, 90...11th frame monitor, 95...
・Electronic processing location, 97...Interface, 100...Durable memory iA head. Daikonto Asa H Koshi procedure rFj rE book January 2nd, 1988

Claims (1)

[Claims] (1) Continuously and automatically monitors a large surface of a metal material moving at high speed, detects and analyzes surface changes that exceed predetermined allowable surface conditions, and rejects A method for determining the presence of a surface defect to be determined and for accurate classification of the defect, the method comprising: a method for determining the presence of a surface defect to be determined and for accurate classification of the defect; homogenizing the moving surface with at least one of visible and non-visible reflections and diffused electromagnetic radiation within the wavelength range determined by the moving surface; and momentarily rendering the fast moving surface immobile; detecting the presence of one or more rejectable defects by a plurality of sensors arranged to view the entire width of the material; one or more for subsequent display and analysis; sending this image to a device for storing an electronic image of the defect-containing area from a further sensor, said image having gray scale levels representative of the varying intensity of electromagnetic energy reflected by the defect; providing a range of grayscale levels representing a range of reflected electromagnetic energy intensities from a surface having no defects to be rejected; and providing a range of grayscale levels of the image having defects; comparing the surface with a range of grayscale levels representing a surface having no defects to be rejected; and an image of a surface having grayscale levels outside the grayscale intensity range representing a surface having no defects to be rejected; A method for inspecting a moving metal surface, the method comprising: observing and analyzing a moving metal surface on a frame-by-frame monitor; (2) In claim 1, the reflected radiation is directed from a position above the moving surface and the diffused radiation is directed in a direction substantially parallel to the surface, so that both types of A method for inspecting a moving metal surface, comprising the step of: arranging said radiation to uniformly illuminate the entire width of said surface. (3) In claim 1, each frame has 51
Using a side-by-side video camera using a two-scan line NTSC standard, 0.305 mm of the surface in a direction in which the surface is moving at a speed of 1800 feet per minute or multiples thereof.
images of one or more defects to be rejected on the moving surface in a direction across the width of the surface during a distance of 1 foot (60 m) per second or multiples thereof. A method for inspecting a moving metal surface, the method being adapted to detect said surface defects by capturing the surface at a velocity.