JPH0666070B2 - Pattern processor - Google Patents

Description

Description: TECHNICAL FIELD The present invention captures an unknown pattern using an imaging device such as an ITV (Industrial Television Projection) camera, and outputs an imaging signal obtained as a result of analog / digital ( The present invention relates to a pattern processing device that converts an analog pattern by an A / D converter and processes an unknown pattern based on the degree of matching between the digital signal and an enlargement / reduction pattern created in advance.

[Prior art and its problems]

Conventionally, in this type of device, a) most of the standard patterns for matching have only prepared reduced patterns.
It is not possible to detect stains or scratches on the outside of the object pattern.

(B) As shown in FIG. 4, there are some that have image enlargement / reduction functions. However, since this enlarges / reduces the inspection pattern itself, not the standard pattern, defects may occur depending on the degree of enlargement / reduction. It may not be detected. The detection process in FIG. 4 is as follows. When is the pattern to be inspected in the figure, a magnified pattern such as is obtained by enlarging the pattern, and the concave portion F _{1 of the} original pattern PA is erased by this magnifying operation. Next, if the enlarged pattern is reduced as shown in FIG. 3 and the difference between the enlarged pattern and the original pattern is taken, only the concave portion F ₁ is extracted as shown in. On the other hand, if the original pattern is scaled down, then scaled up and the difference is taken, only the convex portion F ₂ is extracted as shown in ', and by combining these, the concave portion and the convex portion are detected as . However, when the original pattern is enlarged or reduced, the concave portions and the convex portions may remain as they are depending on the degree of the original pattern. Therefore, in such a case, detection becomes impossible.

C) Since only the enlargement or reduction pattern for matching having a certain predetermined magnification is prepared, a misjudgment is likely to occur due to a positional shift or variation.

D) It is created from the enlarged or reduced pattern by hardware (by a filter etc.) or software (by a computer operation), but since this pattern is stored as it is in the memory as a matching pattern and used for judgment, Depending on the object, some parts may require a mask, and some may deal with cases where it is desirable to change the enlargement ratio (reduction ratio) in the upper half and lower half of the target pattern. It is not possible, and as a result, an erroneous determination is likely to occur.

E) One matching pattern is assigned to one target object to perform matching, that is, the matching degree is evaluated by one operation, so that even if the matching degree varies from region to region An accurate judgment cannot be made because it is determined by evaluation.

[Object of the Invention]

The present invention has been made in view of the above points, and it is possible to easily enlarge and reduce a reference pattern and to appropriately select a combination of an unknown pattern and an enlargement or reduction pattern, thereby providing flexibility. An object of the present invention is to provide a pattern processing device capable of highly accurate pattern processing.

[Main points of the invention]

According to the present invention, an enlarged pattern generating means for enlarging an image pickup signal obtained by picking up a digital image of a standard pattern corresponding to an unknown pattern and digitizing it, an enlarged pattern memory for storing the enlarged pattern generation means, and a variety of the image pickup signals for the same. A reduced pattern generation means for reducing at a rate of, a reduced pattern memory for storing the reduced pattern memory, an image memory for storing an image pickup signal obtained by digitalizing an unknown pattern and digitizing the unknown pattern, and specifying an area from each of these memories. A control means for reading data is provided, and the control means selectively retrieves the contents of each memory to perform a predetermined operation, thereby enabling pattern processing with a large degree of freedom and high accuracy. .

Example of Invention

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram illustrating the operation according to the present invention. First
In the figure, 1 is an image pickup device such as an ITV camera, 2 is an amplifier, 3 is an analog / digital (A / D) converter, 4 is an enlarged pattern generator, 5 is a reduced pattern generator, 6 is an enlarged pattern memory, and 7 is an enlarged pattern memory. Is a reduction pattern memory, 8 is an arithmetic processing unit (CPU) such as a microcomputer, 9 is an image memory, 10 is a photographing area totalizer, 11 is a change point coordinate detector, 12 is a scan controller, 13 is an arithmetic circuit, and 14 is The counter, 15 is a bus.

First, before processing an unknown pattern, a standard pattern corresponding thereto is processed. That is, the standard pattern is picked up by the ITV camera 1, the picked-up image signal obtained as a result is amplified by the amplifier 2, and is converted into a digital signal by the A / D converter 3. Enlarged pattern generator 4
Of the digitally-encoded image signal is enlarged (thickened) at various magnifications and stored in the memory 6 as an enlarged pattern. Similarly, the reduced pattern generator 5 reduces (narrows) the digitized image pickup signal at various ratios, and stores each in the memory 7 as a reduced pattern.

Next, if the unknown pattern is the same as above, the ITV camera 1,
It is digitized through the amplifier 2 and the A / D converter 3 and stored in the image memory 9. At this time, the output from the A / D converter 3 is also given to the imaging area totalizer 10 and the change point coordinate detector 11, and the horizontal or vertical projection value of the unknown pattern and the pixel from white to black or black. The coordinates of the change point to white are detected and stored. The projection value and the change point coordinate information are given to the arithmetic processing unit 8 as position data representing an area where the unknown pattern exists. Based on this position data, the arithmetic processing unit 8 instructs the scan controller 12 to read each area of the image memory 9, the enlarged pattern memory 6 and the reduced pattern memory 7 to be scanned. The data read from each of the memories 6, 7, 9 is given to the arithmetic circuit 13, where the matching value between the unknown pattern and the enlarged pattern and the matching value between the unknown pattern and the reduced pattern are calculated. The counter 14 counts these matching values, and the arithmetic processing unit 8 performs predetermined image processing based on this count value. The arithmetic processing unit 8 has a correction function for correcting necessary portions of the enlarged and reduced patterns and a mask function of the required portions.

The determination operation according to the present invention will be described below with reference to FIG.

The figure shows an inspection pattern, and is a standard pattern.
If the standard pattern is reduced or expanded and each pattern is designated as ′, a matching operation between these and the inspection pattern, ′, is performed. As a result, it is possible to detect the defect (chip, crack) S ₁ inside the pattern from the matching operation with the reduced pattern, while the matching operation with the enlarged pattern is performed.
It is possible to detect defects (burrs, stains) S ₂ outside the pattern as shown in ′. Now, the inspection pattern is i (m, n),
The reduction pattern is expressed in a matrix like d ₁ (m, n) and the expansion pattern is expressed as d ₂ (m, n), and the part where the pattern exists is “1”.
(White) and other backgrounds such as “0” (black), the defect X ₁ inside the pattern and the defect X ₂ outside are respectively Can be expressed as Here, (∧) represents an AND operation and (−) represents an inversion operation. Also,
Enlarging is defined as enlarging a white part (portion where data is "1"), and reducing is defined as reducing a white part.

FIG. 3 is an explanatory diagram for explaining a method of dividing an inspection area into a plurality of pieces and performing matching.

That is, when inspecting the pattern PA as shown in the figure, if the matching degree is counted as one pattern, defects such as P ₁ and P ₂ are included in the overall variation and quantization error. Therefore, the determination accuracy can be improved by dividing the pattern PA into four areas A to D as shown in the figure and individually matching them.

〔The invention's effect〕

According to this invention, the following effects can be expected.

1) Since the enlarged and reduced patterns of the reference pattern are prepared, it is possible to detect defects outside the target pattern.

2) Since detection is performed by comparison with the reference pattern,
Defects can be detected regardless of the enlargement or reduction ratio.

3) By preparing various magnification patterns,
It is possible to deal with positional deviation and dimensional variation.

4) Since the enlargement / reduction pattern can be appropriately corrected by the arithmetic processing unit, erroneous determination can be reduced.

5) Since the patterns having different enlargement ratios and reduction ratios can be used in combination, the determination accuracy is improved.

6) One object is divided into a plurality of regions, a matching operation is performed for each region, and the results can be comprehensively determined, which enables highly accurate determination.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory view schematically showing the operation according to the present invention, and FIG. 3 is a diagram for explaining a method of matching by dividing an inspection area into a plurality of parts. 4 is an enlarged view of the inspection pattern itself.
It is explanatory drawing for demonstrating the conventional example of the method of reducing and inspecting. Explanation of code 1 …… ITV camera (imaging device), 2 …… Amplifier, 3 ……
Analog / digital (A / D) converter, 4 ... Enlarged pattern generator, 5 ... Reduced pattern generator, 6 ... Enlarged pattern memory, 7 ... Reduced pattern memory, 8 ... Arithmetic processing unit (microcomputer ), 9 ... Image memory, 10 ... Projected area aggregator, 11 ... Change point coordinate detector,
12 …… Scan controller, 13 …… Arithmetic circuit, 14 ……
Counter, 15 …… Common bus.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-52-93248 (JP, A) JP-A-58-9090 (JP, A) JP-A-55-117944 (JP, A) JP-A-49- 131543 (JP, A) JP 57-48163 (JP, A) JP 50-141355 (JP, A) JP 58-115583 (JP, A) JP 56-116185 (JP, A) JP-A-56-4880 (JP, A)

Claims (1)

[Claims] 1. A conversion means for converting an image pickup signal obtained through the image pickup means into a digital signal, an image memory for storing an image pickup signal obtained through the image pickup means and the conversion means for an unknown pattern, and the image pickup signal. Feature extraction means for extracting various feature amounts such as the projected area pattern of the unknown pattern and the change point coordinates from the image pickup signal obtained through the image pickup means and the conversion means for the standard pattern corresponding to the unknown pattern at various magnifications. An enlarged pattern memory for enlarging and storing, a reduced pattern memory for reducing and storing an image pickup signal for a standard pattern corresponding to an unknown pattern at various magnifications, and reading of the image memory and each of the enlarged and reduced pattern memories. Unknown based on the scan controller to control and the data from the feature extraction means Operation control means for discriminating an area in which a turn exists, setting inspection areas divided into a plurality of areas, and instructing the scan controller for an area to be scanned in each memory for each inspection area, A pattern processing apparatus comprising: a calculation unit that performs a predetermined calculation based on read data, and pattern processing is performed from the calculation result.