JPS62135752A - Defect detecting device - Google Patents

Abstract

PURPOSE:To detect exactly a defect even if the set value of a discriminating level is changed in an image scanning period, by inspecting whether the set discriminating level is correct or erroneous, and changing the discriminating level by synchronizing with an image signal when said level is correct. CONSTITUTION:When an image sensor output S1 synchronizing with a start signal S4 is being detected as to its defect by am amplifier 23, discriminators 24a, 24a and magnitude discriminators 25a, 25b, if discriminating levels V1, V2, D1, and D2 are changed through a setting device 26, a changed data is stored in a temporary data memory 28. A CPU 29 compares this data with a data set in advance, and when it is normal, data changing signal S5 is outputted to a start signal generating circuit 32, and also new data V1, V2, D2, and D2 in the memory 28 are transferred to memories M1-M3. When the signal S5 is inputted, the circuit 32 outputs a data transfer signal S6 to the memories M1-M3, and new discriminating levels V1, V2, D1, and D2 are outputted. The discriminators 24a, 24b, and the discriminators 25a, 26b detect the defect of the output S1 by new discriminating levels V1, V2, D1, and D2 from the next scan.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a defect detection device, and more particularly to a discrimination level setting circuit for a device that detects defects by image scanning.

<Summary of the Invention> The present invention stores the set discrimination level, checks whether the discrimination level is correct or not, and outputs it to the discrimination means in synchronization with the image signal if it is correct, thereby setting the discrimination level during scanning. It is characterized by being able to always accurately detect defects in the object to be inspected even if the value changes.

<Prior Art> As shown in FIG. 4, an apparatus for detecting defects in an object to be inspected by image scanning amplifies an image signal from an image sensor 1 using an amplifier 2, and then discriminates the defects using discriminators 3a and 3b. , the size of the defect is determined by size discriminators 4a and 4b, respectively, and output to the processing section 5 at the subsequent stage. The reason why two systems of discriminators 3a and 3b and size discriminators 4a and 4b are provided is to detect two types of defects, and a one-thread type is also known.

In a conventional defect detection device of this type, a discriminator 3a.

3b's discrimination level V, , V, and size discriminator 4a,
When setting the discrimination level D, , D, for the size of the defect of 4b, the operator manually sets it in the setting device 6, and after temporarily storing the set data in the buffer circuit 7, the discriminator 3 a, 3 b, size discriminator 4
A and 4b were output directly, and the discrimination level was set for each.

<Problems to be Solved by the Invention> However, in the discrimination level setting circuit of the defect detection device as described above, if the discrimination level setting value is changed during image scanning, the discrimination level data is not determined. The interval is the discrimination level/l of discriminators 3a, 3b and discriminators 4a, 4b.
There is a problem that /V, , V, , [), , D, may become O, resulting in malfunction. .

On the other hand, in order to solve the above problems, the output to the detection unit 5 is prohibited for a predetermined period of time when the set value of the discrimination level is changed, and the discrimination level V, , V, .

A method in which D, , D, is the lowest sensitivity is also known, but in this case, there is a problem that accurate defect detection cannot be performed during the above-mentioned predetermined time.

Further, if the discrimination level is set incorrectly, it is output as is to the discriminators 3a, 3b and size discriminators 4a, 4b, so there is a problem that accurate defect detection cannot be performed.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an apparatus that can always accurately detect defects even if the set value of the discrimination level is changed during scanning.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides means for imaging an object to be inspected by image scanning, and means for determining defects of the object to be inspected based on image signals from the imaging means. a means for setting the discrimination level of the discrimination means; a means for storing the discrimination level set in the setting means; a correctness test for the discrimination level stored in the storage means; It is characterized by comprising means for outputting to the discrimination means in synchronization with the image signal.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a defect detection device according to the present invention, FIG. 2 is a schematic configuration diagram of the device shown in FIG. 1, and FIG. 3 is a timing chart of main signals.

The device of this embodiment is of a transmission type as shown in FIG.
Image sensors 1 arranged in the dimensional direction (main scanning direction)
An object to be inspected 12 is placed between the light source 11 and the light source 11, and the object to be inspected 12 moves in a direction perpendicular to the plane of the paper (sub-scanning direction).

The output of the image sensor 10 repeats a blank period and an image signal for each scan, as shown in S in the iR3 diagram.
Dirt a and holes are imaged. The stains a and holes are discriminated by discrimination levels V, , V, which will be described later. The output SI is input to a control section 20, and this control section 20 has a discrimination level setting section 21 and a defect detection section 22.

As shown in the lower part of FIG. 1, the defect detection unit 22 includes an amplifier 23 that amplifies the output S1 of the image sensor 10, and a discriminator 24a that discriminates the dirt a on the inspection object 12 based on the discrimination level V and converts it into a binary value. and discrimination level V.

A discriminator 24b discriminates the hole b1 of the object 12 to be inspected and converts it into a binary value.The discriminator 24b determines whether the stain a is normal or not based on the discrimination level D, which determines the size of the stain a (the width of the signal S in FIG. 3). Size discriminator 25 & and discriminator 2 for determining whether it is a defect
The size of the hole determined by 4b is the signal S in Fig. 3,
A size discriminator 25b is provided for discriminating whether the width is normal or defective based on the discrimination level D.

The outputs of the size discriminators 25a and 25b are sent to the subsequent processing section 3.
3 and undergoes known processing.

As shown in the upper part of FIG.
5a and 25b at each level V1. V.

It has a setter 26 for setting data such as D, , D, etc., and a temporary data memory 28 for inputting and storing the data from the setter 26 via a buffer circuit 27. The temporary data memory 28 also stores in advance, via the setter 26, data such as the highest and lowest values of discrimination levels that are inappropriate for defect detection.

The setting section 21 further includes a central processing unit 29 that periodically checks the contents of the temporary data memory 28 and performs overall control of each circuit of the main setting section 21, and a setting device 26 for controlling the contents of the temporary data memory 28. A memo that stores data for levels V, , V, and Dl and RI! J M 1 , M2゜M3 and level vI from notes IJ M 1 and M2 respectively
and V, into analog signals. Start signal generation circuit 3
2 outputs a start signal S4 for the image sensor 10, as shown in FIG. 3, and also outputs a data transfer signal S6 as described later.

In the above configuration, the image sensor output S synchronized with the start signal S4 is transmitted to the amplifier 23. During the defect detection by the discriminators 24a, 24b and the size discriminators 25a, 25b, the discrimination level VI +Vt + DI is set via the setting device 26.
r When D2 is changed, this changed data (third
The signal SX) in the figure is stored in the temporary data memory 28.

The CPU 29 compares the changed data in the temporary data memory 28 with preset data such as the highest value and the lowest value to determine whether it is normal or not, and if it is normal, sends the data change signal S, ( 3) to the start signal generation circuit 32, and also memorizes the new data V, , V, Tori, and IJMI in the temporary data memory 28, respectively.
, M2. Transfer to M3.

When the start signal generation circuit 32 receives this data change signal S, it memorizes the data transfer signal S synchronized with the start signal S4 of the image sensor 10! J.M.I.

Output to M2, M3, new data V, , V,
,D.

D, respectively, are discriminators 24a, 24br, and size discriminator 25a.

25b. The discriminators 24a, 24b and the size discriminators 25a, 25b each obtain a new discrimination level V, , V, , D, from the next image scan.
, D2 detects defects in the image sensor output S1.

That is, since the video signal of the image sensor output S is in a blank state during the period of the start signal S of the image sensor 10, correct defect detection is possible even if the discrimination level is changed during one scanning period.

<Effects of the Invention> As explained above, the present invention is configured to check whether the set discrimination level is correct or not, and if it is correct, change the discrimination level of the discrimination means in synchronization with the image signal. Even if the set value of the discrimination level is changed during the process, it is possible to detect defects accurately.

Furthermore, since the present invention is configured to check whether the discrimination level set value is correct or incorrect, accurate defect detection is possible even if the set value is changed incorrectly.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a defect detection device according to the present invention, and FIG.
1 is a schematic configuration diagram of the device shown in FIG. 1, FIG. 3 is a timing chart of main signals of the device shown in FIG. 1, and FIG. 4 is a block diagram of a conventional example. 10... Image sensor, 12... Test object, 24
a. 24b... Discriminator, 25a, 25b... Size discriminator, 26... Discrimination level setter, 28... Temporary data memory, 29... Central processing unit, 32... Start signal generation circuit.

Claims (1)

[Claims] means for imaging an object to be inspected by image scanning; means for determining defects in the object based on image signals from the imaging means; means for setting a discrimination level of the discrimination means; and discrimination set in the setting means. A defect detection device comprising means for storing a level, and means for checking whether the discrimination level stored in the storage means is correct or not, and outputting the discrimination level to the discrimination means in synchronization with the image signal if the discrimination level is correct.