JPS6321857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface inspection device for optically inspecting a moving elongated object for surface defects.

BACKGROUND ART Visual surface inspection is performed on rolling lines for long objects such as steel plates and aluminum plates.
When automating this visual inspection, it is necessary to create a device that resembles the inspection procedure used by visual inspectors in order to obtain judgments similar to those obtained through visual inspection. Visual inspectors instantly make the following judgments:

1 Determine the type of flaw based on its distribution, shape, depth, density, etc.

2 If there are several flaws in a certain plane,
Judgment is made by focusing on typical flaws.

3 Classification is done using established criteria (often based on empirical factors) depending on the type of flaw.

4 The above judgments are made depending on the material, surface finish, etc. of the target long object.

When replacing these judgments with machines and automating them, the signal processing speed cannot keep up with the line speed, which poses a major obstacle.

The present invention has been made in response to the above points, and
Create a profile of the surface of a long object, select the longest or widest flaw from the shape of the flaw obtained from the profile as a representative flaw, and determine the grade using the weighting value of the representative flaw. The purpose of the present invention is to provide a surface inspection device configured to detect surface defects in the line speed and capable of sufficiently following the line speed.

1 to 3 for one embodiment of the present invention.
This will be explained with reference to the figures.

First, the configuration of one embodiment will be described with reference to FIG.

Reference numeral 10 denotes a detection head section that optically scans the long object 11 in the width direction and converts reflected light from the surface of the object 11 into an electrical signal. This detection head section 10 is connected to a discrimination circuit 13 via an amplifier 12. This circuit 13 includes the head section 1
The signal from 0 is discriminated in multiple stages. For example, it is configured to discriminate at three levels: γ ₁ (low), γ ₂ (medium), and γ ₃ (high), and the discriminated signal is output as a flaw signal. This discrimination circuit 13
is connected to a profile generation circuit 15 via a flaw position detection circuit 14. This circuit 15 sequentially counts the flaw signal outputted for each scan of the head section 10 for each position in the width direction of the object 11 based on the position signal of the flaw position detection circuit 14, A profile is created for each section using signals from the signal generation circuit 16.

Further, this profile generation circuit 15 is connected to a representative flaw selection circuit 17. This circuit 17
selects the longest or widest shaped flaw from the profile as a representative flaw, and supplies the signal of the representative flaw to the subsequent flaw type discrimination circuit 18. This circuit 18 determines whether the representative flaw is an arbitrarily selected specific flaw (for example, the most important flaw) or another flaw. Also, this circuit 18
supplies the representative flaw signal to the weighting circuit 20. The weighting circuit 20 is configured to set ρ ₁ > according to the discrimination levels γ ₁ , γ ₂ , γ ₃ from the setting device 21, for example.
Weighting signals ρ ₁ , ρ ₂ , ρ 3 having the relationship ρ _{2 >} ρ ₃ are supplied. Then, this circuit 20 determines the weight value φ of the representative flaw from the weighting signals ρ ₁ , ρ ₂ , ρ ₃ and the representative flaw signal using the following equation.

φ=(ρ ₁・〓R ₁ ) +(ρ ₂・〓R ₂ )+(ρ ₃・〓R ₃ ) (However, in the formula, R ₁ , R ₂ , R ₃ are the defects at each discrimination level. Further, this weighting circuit 20 is connected to a subsequent grade determination circuit 22. This circuit 22 determines the grade of the weighted representative flaw, and determines the grade by comparing the weight value φ of the representative flaw with the judgment level φk set by the setting device 21. .

Further, as described above, the setting device 21 sets the weights ρ ₁ , ρ ₂ , ρ ₃ and the judgment level φk for each discrimination level, and each of these values is received from the flaw type discrimination circuit 18. This is changed depending on the determination result and the type of material or surface finish of the object 11.

A position pulse generator 23 outputs a signal for determining the position of a flaw and a profile creation unit, that is, a section serving as an inspection unit on the surface of the object 11. This flaw location is obtained as follows. In other words, the longitudinal position determines the position of the object 11 in order to output pulses corresponding to the traveling speed of the object 11.
The signal counted from the time when the object 11 passes through the head section 10, and the position in the width direction are determined by sending pulses output during constant scanning from one end of the object 11 to the subsequent flaw position detection circuit 14. Detected. In this detection circuit 14, the longitudinal position is determined from the pulse count value in the longitudinal direction when the flaw signal arrives from the discrimination circuit 13, and the width direction position is determined from the pulse count value in the width direction, respectively, and these are made to correspond to the flaw signal.

Further, the division of one inspection unit is determined by the division signal generation circuit 16 from the pulse count value in the longitudinal direction, for example.
This can be done by outputting one pulse in units of 100 pulses.

Further, 25 is an output control circuit which receives the flaw position detection signal from the flaw position detection circuit 14 and the flaw type discrimination circuit 1.
The flaw type signal from 8 and the grade from grade determination circuit 22 are supplied to display 26 and typewriter 27.

Next, the operation of one embodiment configured as described above will be explained.

By optically scanning the surface of the running elongated object 11 in the width direction, reflected light from the surface enters the detection head section 10 and is converted into an electrical signal as shown in FIG. 2a. This signal is subjected to pulse height discrimination by a discrimination circuit 13 via an amplifier 12 at discrimination levels of γ ₁ , γ ₂ , and γ ₃ as shown in FIG. 2b, c, and d. This pulse height discrimination is performed for each scan of the head section 10, and the output of this discrimination is supplied to a flaw position detection circuit 14, which outputs a position pulse generator 23.
The signal is outputted as a flaw position signal to the profile generation circuit 15 at the subsequent stage. In this profile generating circuit 15, the flaw position signal shown in FIG.
Create a profile like the one shown below. In addition, the same figure a
1 shows the surface of the object 11, and A, B, and C are flaws on the surface. This profile is created by summing up each section signal from the section signal generation circuit 16. Then, the longest or widest flaw from this profile generation circuit 15 is extracted as a representative flaw by the subsequent representative flaw selection circuit 17. This representative flaw signal is then supplied to the flaw type discrimination circuit 18,
Here, it is determined whether or not it is a specific flaw. The determination result is sent to the setter 21, and the setter 21 changes the values of β ₁ , β ₂ , β ₃ and φk according to the result. Further, the representative flaw signal that has passed through the flaw type discrimination circuit 18 is supplied to the weighting circuit 20.

Here, the number of flaws R ₁ , R _{2 , R 3 for each discrimination level γ 1 , γ 2 , γ 3 of the representative} flaw signal is multiplied by the weights β ₁ , β ₂ , β ₃ from the setter 24 and summed. Determine the weight value φ.
This determined weight value φ is supplied to the grade determination circuit 22, compared with the determination level φk from the setter 21, and graded.

The grade of the representative flaw from the grade determination circuit 22, the flaw type of the representative flaw from the flaw type discrimination circuit 18, and the flaw position signal from the flaw position detection circuit 14 are transmitted via the output control circuit 25 to the display. 26 or a typewriter 27, and the surface defect inspection of the object 11 is completed.

Since the present invention is configured in this manner, it is possible to automatically perform a surface inspection similar to a visual inspection, and it also has the advantage of being able to sufficiently follow the line speed.

[Brief explanation of the drawing]

The figure explains one embodiment of the present invention.
The figure is _a circuit configuration diagram _, FIG _. A plan view showing flaws on the surface; FIG. 10...Detection head part, 11...Long object, 1
2...Amplifier, 13...Discrimination circuit, 14...Flaw position detection circuit, 15...Profile generation circuit, 16
...Division signal generation circuit, 17 ... Representative flaw selection circuit, 18 ... Flaw type discrimination circuit, 20 ... Weighting circuit, 21 ... Setting device, 22 ... Grade judgment circuit, 2
3...Position pulse generator, 25...Output control circuit, 26...Display section, 27...Typewriter.

Claims (1)

[Claims] 1 In a device that scans the surface of a moving long object in the width direction with a beam of light and inspects defects on the object surface from changes in reflected light from the object, the device scans the object surface in the width direction and detects defects from each point on the object surface. a detection head section that converts reflected light into an electrical signal; a discrimination circuit that discriminates the pulse height of a pulse signal due to a flaw on the object surface included in the signal from the detection head section at multiple discrimination levels; a position pulse generator that generates a pulse signal for each unit length in the longitudinal direction and width direction of the object, and also generates a position signal that partitions the object surface at regular intervals in the longitudinal direction; When the tip of the object passes through the detection head, the longitudinal pulses from the position pulse generator are counted, the longitudinal position of the flaw is detected from the counted value at the flaw occurrence point, and the width of the flaw is determined from the width direction pulses. a flaw position detection circuit for detecting a directional position; and a flaw position detection circuit connected to this circuit to detect flaw signals at each width direction position for each scanning signal of the detection bed section on an object surface divided by signals from the position pulse generator. A pull foil generation circuit that counts within one section, a representative flaw selection circuit that selects a representative flaw from the flaw counting signal for each width direction position within one section from this generation circuit, and a representative flaw selected by this circuit. A flaw type discriminating circuit that determines whether the flaw is an arbitrarily selected specific flaw or another flaw, and a weight ρi for each discrimination level of the discriminator circuit, and a flaw grading level ψk based on the type of object material, surface finish, etc. A setting device that sets based on the determination result of the flaw type discriminating circuit, and a weight for each discrimination level from the setting device on the number of defects for each discrimination level of the representative flaw signal supplied through the flaw type discriminating circuit. A weighting circuit that integrates and sums ρi, a grading circuit that compares the weighted signal from this circuit with the grading level ψk from the setting device to determine the grade of the representative flaw, and this grading judging circuit. and an output control circuit that outputs information on representative flaws for each section of the object from the signal from the profile generation circuit to a subsequent display or typewriter.