JPS60117385A - Pattern recognizing method and its pattern recognizing device - Google Patents

Abstract

PURPOSE:To improve the recognition rate of a pattern to be recognized, by finding the degree of correlation between the pattern areas of an input pattern and dictionary pattern. CONSTITUTION:An analog signal from an image pickup system 2 is digitized at a binary coding circuit 3 and the digitized signal is stored in a frame memory 4. By providing a dictionary pattern extension-contraction controlling circuit 8 which compares the pattern area of a pattern to be recognized of the frame memory 4 with the pattern area of a dictionary memory 6 and performs extension or contraction of a dictionary pattern in accordance with the compared result, the degree of correlation between the pattern to be recognized and the dictionary pattern after extension or contraction is found by a pattern matching circuit 5 and pattern recognition is performed.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a pattern recognition method and a pattern recognition device using the same, and in particular, the invention relates to a pattern recognition method and a pattern recognition device using the same. The present invention relates to a pattern recognition method that causes scaling and a pattern recognition device that recognizes a pattern to be recognized using this method.

(σ) Technology Background Pattern recognition devices include Ii! There is a demand for achieving a reduction in the false recognition rate while improving the weaving rate.

One type of this type of device is one that uses a pattern matching method, and the above-mentioned requirements still exist for that device as well.

However, devices using the pattern matching method and conventional techniques have a problem in that, due to their inherent characteristics, when attempting to increase the recognition rate, the false recognition rate also increases.

(C) Prior art and problems In devices using conventional pattern matching methods, a dead area is set in the dictionary pattern as a means of dealing with thickening or thinning of the recognized pattern, and the dictionary pattern and the recognized pattern are There is a method that attempts to recognize patterns by performing pattern matching. According to this technique, the g recognition rate improves when the recognized pattern is correct, but since it is easy to match incorrect patterns with dictionary patterns, there is an undesirable tendency that the misrecognition rate also increases. has.

Object of the Invention The present invention was devised in view of the drawbacks of the conventional techniques as described above, and its purpose is to create a dictionary pattern corresponding to the regional magnitude relationship that exists for the dictionary pattern of the input pattern. To provide a method for enlarging/reducing a dictionary pattern by regionally enlarging or reducing it, and a pattern recognition device capable of improving the recognition rate and reducing the false recognition rate by using the resulting dictionary pattern obtained by this method for pattern recognition. It is in.

(G) Structure of the Invention In order to achieve this object, the method of the present invention calculates the area difference between the human cover pattern and the dictionary pattern, and the dictionary pattern is expanded or contracted according to the result. an imaging system, a binarization circuit that digitizes an analog signal from the imaging system, a frame memory that stores the digital signal, a dictionary pattern memory, a pattern area of the recognized pattern of the frame memory, and the above-mentioned book. Compare the pattern area of the dictionary pattern in the pattern memory,
A dictionary pattern enlargement/reduction control circuit for enlarging or reducing the dictionary pattern according to the result, and a pattern matching circuit for determining the degree of correlation between the one protected pattern and the dictionary pattern after the enlargement or reduction. It is configured to perform pattern recognition.

(F) Embodiments of the Invention The present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the invention. In this figure, 1
is a mask sample for obtaining a dictionary pattern or a recognition target for obtaining a recognized pattern. Reference numeral 2 denotes an imaging system that images a mask sample or a recognition object, and 3 a binarization circuit that digitizes an analog signal from the imaging system 2. 4 is a frame memory that stores digital values;
Its output is a pattern matching circuit 5 and a dictionary memory 6.
connected to. 7 is the output of the circuit 5 and the dictionary memory 6
The control system is connected to the control system and has a recognition result output terminal.

A dictionary pattern expansion/reduction control circuit (pattern width control circuit) 8 is connected to the frame memory 4 and the dictionary memory 6.
This is a characteristic part of the present invention.

This pattern width control circuit 8 includes an area counting circuit 9 connected to the frame memory 4, a dictionary pattern area memory 10 connected to the output of the circuit 9, and an area comparison circuit 11 connected to the outputs of the circuit 9 and the memory 10. and a pattern width expansion/contraction circuit 12 connected between the circuit 11 and the dictionary memory 6;
and a processing interrupt circuit 13.

The pattern width enlarging/reducing circuit 12 is used for enlarging or reducing the dictionary pattern width and also for setting a dead zone for the dictionary pattern, and is constructed as follows. As shown in FIG. 2, this circuit is designed to enlarge or reduce a two-dimensional dictionary pattern input from the dictionary memory 6 to the processing memory 20. It is expressed as・) When the bit of ) is in the 1-bit shift register 2, the surrounding 8 bits become a 1-bit shift register, and the bit is transferred from the memory to be processed 20 to the shift register 21 so that it exists in 1 to L8, and 1 bit is transferred from the shift register 21. 1 pinto shift register L4. It enters the shift register 23 via Z and La, and then enters the 1-bit shift register i.
A one-bit shift register Z configured to be shifted out via L8 and capable of outputting the contents of the bits shifted in; its output of L8 goes to AND gate 24 and OR gate 25; The output bits of these gates are stored in the result memory 28 via the selection circuit 27 under the control of the sign of the sign section 26A set in the data register 26 from the area comparison circuit 11. . The selection circuit 27 has one input connected to the output of the AND gate 24, the other input connected to the sign part 26A of the data register 26, and one input connected to the output of the OR gate 25, and the other input connected to the output of the OR gate 25. It consists of an AND gate 32 whose input is connected to the sign section 26A of the data register 26 via an inverter 31, and an OR gate 33 whose input is connected to the output of an AND gate 30.32.

Next, the operation of the above-mentioned component device will be explained.

Prior to the pattern recognition process, the dictionary pattern is stored in the dictionary memory 6 as follows. For this purpose, the mask sample 1 is placed within the imaging field of the imaging system 2, and its pattern is imaged, and the analog video signal is converted into a digital video signal by the binarization circuit 3 and stored in the frame memory 4.
is stored in

The contents of the frame memory 4 are stored as a dictionary pattern in the dictionary memory 6, and the pattern area SM of the dictionary pattern is determined by the area counting circuit 9 and stored in the dictionary pattern area memory 10.

After such storage is completed for the required dictionary pattern, the pattern to be recognized from the m-weave object 1 is stored in the frame memory 4 in the same manner as the acquisition of the dictionary pattern, and the recognition process begins.

First, the pattern area SR of the recognized pattern in the frame memory 4 is counted by the area counting circuit 9, and the area comparing circuit 11 compares the area SR with the pattern area SM stored in advance in the dictionary pattern area memory 10. . In this comparison, if the recognized pattern is a narrow pattern, that is, SR<SM (see (3-1) in Figure 3), then
The area comparison circuit 11 indicates 1'' as a contracted sign bit and the contracted width Ws (this is determined by lSR-8M!) to the sign section 26A and data section 26B of the data register 26 of the pattern width expansion/contraction circuit 12, respectively. Data is set.In parallel with this, a dictionary pattern is input from the dictionary memory 6 to the memory to be processed 20.Then, the following dictionary pattern width narrowing process is started.

From the memory to be processed 20, the data first enters the shift register 21, then the 1-bit shift registers L1 to L3, and the shift register 22.1 bit shift register L41 ZI L
5, shift register 23, and 1-bit shift registers L1-L3.6-L8 are being shifted. L4. Z, La, Le~L8
If there is at least one "0" bit (the pattern area is binarized as 1) around the above-mentioned point of interest (Z) in the pattern part represented by , the input condition of the AND gate 24 is The bit that is not satisfied and represents the point of interest is changed to .O'' and is stored in the result memory 29 via the selection circuit 27. Such processing is performed for the entire dictionary pattern. This results in the dictionary pattern being reduced by one bit. The number of times of such processing is determined by the reduction width Ws set in the data register 26, and the above-mentioned processing is repeated that number of times, resulting in (3-2) in FIG.
A narrowed dictionary pattern is generated as shown in (
See also (4-2) in Figure 4, and (4=1) in Figure 4.
・indicates a part of the standard dictionary pattern). (4-
In 2), S is the width W reduced from the standard dictionary pattern width M.
It shows the dictionary pattern width reduced by S.

In this way, a dead area (the width is expressed as WN) is set for the narrowed dictionary pattern (the third
(See (3-2) in Figure 4 and (4-3) in Figure 4). This setting can be performed by using the pattern width enlarging/reducing circuit 12 described above to perform the above-mentioned width narrowing process and the later-described width widening process on the narrowed dictionary pattern. The dictionary pattern with a dead area generated by performing these processes is shown in (3-2) in Figure 3, and an enlarged part of it is shown in (4-3) in Figure 4. . In (4-3) of FIG. 4, As is the pattern width used for pattern matching of the dictionary pattern, and Bs is the pattern width of the dictionary pattern including the dead area.

Furthermore, in the above comparison, the recognized pattern is a thick pattern, that is, SR>SM ((3-3 in Figure 3)).
), the following widening process is performed. For this purpose, shift register 21.1 bits are shifted from memory 20 to be processed, and shift register 22.
1-bit shift register L4, Z, Ls, shift register 23. The manner of shifting pattern bits from 1-bit shift register 6 to L8 is no different from the width narrowing process described above, but between area comparison llFr11 and data register The contents set in the signature section 26A and data section 26B of 26 are different. That is, 0'' is set as the expanded sign bit in the sign section 26A, and the data section 2
Data indicating the widening width WL (this is determined by lSR-3Ml) is sent to 6B. This causes the 1-bit shift registers L1 to Ls, L4 . Z
, L5. If there is at least one 1" bit around the above-mentioned point of interest (Z) in the pattern portion represented by L8 to L8, regardless of whether the bit at that point of interest is "1" or O". , the bit of interest is forcibly set to "1" by the OR gate 25, and stored in the result memory 29 via the selection circuit 27 under the control of the sign bit.

Such processing is performed for the entire dictionary pattern. This results in the dictionary pattern being expanded by one bit. The number of times of such processing is determined by the widening width WL written in the data register 26, and the above-mentioned processing is repeated that number of times, resulting in a widened dictionary pattern as shown in (13-4) in FIG. is generated (see also (4-4) in Figure 4), (4-4 in Figure 4) is generated (see also (4-4) in Figure 4).
In 4), L is the width W expanded from the standard dictionary pattern width M.
It shows the dictionary pattern width expanded by L.

In this way, the insensitive area (its width is WN) for the widened dictionary pattern is shown in (3-4) in Figure 3.
(See also (4-5) in Figure 4), but the setting method is the same as for the narrowed dictionary pattern, and the above-mentioned method for the widened dictionary pattern. It is like setting by performing width narrowing processing and width widening processing.

Furthermore, in the above comparison, if the processing interruption circuit 13 detects that l SR-3M l is larger than the set value, the two patterns being processed are completely different, and the above-mentioned series of processing is continued. interrupt. by this,
Recognition time can be shortened.

By performing pattern matching between the dictionary pattern obtained through the above-described processing and the recognized pattern, it is possible to improve the recognition rate and reduce the false recognition rate.

An example of this will be explained with reference to FIG.
As shown in 1), when pattern matching is performed using the conventional technique, that is, a dictionary pattern for the letter O in which a blind area is simply set for the standard dictionary pattern, and the recognized pattern for the letter C, there is no matching with the dictionary pattern. can be obtained over a wide area, and the only mismatched area is the shaded area in the figure.
According to the present invention, the width narrowing process is performed prior to the pattern matching, and pattern matching with the dictionary pattern is performed, so that the mismatched portions (5-2) in FIG.
> As shown in the figure, this occurs over a wide diagonal area, and the degree of erroneous recognition of the pattern to be recognized can be significantly reduced.

In addition, in the above embodiment, an example was explained in which the area of the pattern is used in the narrowing process and the widening process, but alternative means for acquiring the above-mentioned signature and data may be used as long as the intended purpose can be realized. The present invention does not exclude this.

(g) Effects of the Invention As described above, according to the present invention, it is possible to: ■ generate a dictionary pattern that is most suitable for the pattern to be recognized, ■ thereby improving the recognition rate of the pattern to be recognized; Effects such as a reduction in the misrecognition rate can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a detailed diagram of the pattern width expansion/reduction circuit of the embodiment in FIG. 1, and FIGS. 3 and 4 are patterns used to explain the embodiment in FIG. 1. 5 are pattern diagrams used for detailed explanation of the present invention. In the figure, 1 is a mask sample or recognition target, 2 is an imaging system, 3 is a binarization circuit, 4 is a frame memory, 5 is a pattern matching circuit, 6 is a dictionary memory, 7 is a control system, and 8 is a pattern width An expansion/contraction control circuit (9 is an area counting circuit, 10 is a dictionary pattern area memory, 11 is an area comparison circuit, and 12 is a pattern width expansion/contraction circuit). Figure 5 Procedural amendment (voluntary) 1. Indication of the case Patent Application No. 225625 of 1982 3. Person making the amendment Relationship in the case Patent applicant address 1015 Nikodanaka, Nakahara-ku, Yozaki City, Kanagawa Prefecture (
522) Name Fujitsu Ltd. 4 Representative Director Address 1015 Koide Nakahara-ku, Yozaki City, Kanagawa Prefecture (1) "Blind area" on page 10, line 19 of the specification of the present application is referred to as "Blind area W" to correct. (2) "Mismatched portion" written in lines 7 to 8 of page 14 is corrected to "mismatched portion F." (3) Correct the "mismatched part" on page 14, line 11 of the same page to "mismatched part F." (4) Figures 3 and 5 attached to the specification of the present application are amended as shown in the attached sheet. 9. Attached documents Figures 3 and 5 of the above amendments ---------- Part 1 Figure 3 (3-4) (3-2), 5M SM w w JP-A-Sho GO-117385 (8) Figure 5 ＼ = zo 10″ to 832w.

Claims (1)

[Claims] (In a pattern recognition method using a pattern matching method in which 11 person cover turns and a dictionary pattern created in advance are matched and the degree of correlation between the two patterns is counted, the dictionary pattern is the same as the entered cover turn. A pattern recognition method characterized in that the degree of mismatch with the dictionary pattern is determined, and the dictionary pattern is expanded or contracted according to the result. (2) The degree of mismatch is determined by comparing the pattern areas of the two patterns. Claim 1 characterized in that
Pattern recognition method described in section. (3) An imaging system, a binarization circuit that digitizes the analog signal from the imaging system, a frame memory that stores the digital signal, a dictionary pattern memory, and a pattern area of the recognized pattern in the frame memory. a dictionary pattern enlargement/reduction control circuit that compares the pattern area of the dictionary pattern in the dictionary pattern memory and enlarges or reduces the dictionary pattern according to the comparison result; 1. A pattern recognition device comprising: a pattern matching circuit for determining the degree of correlation between the patterns; (4) A patent characterized in that the dictionary pattern enlargement/reduction control circuit is configured to notify a processing interruption circuit to that effect and interrupt the recognition processing when the difference between the areas of the two patterns exceeds a preset value. A pattern recognition device according to claim 3.