JPH03217981A - Pattern recognizer - Google Patents

Abstract

PURPOSE:To shorten the pattern recognizing time by providing a spiral scan processing means which scans spirally a dictionary pattern to a pattern to be checked, a scanning start point position correcting means, and a pattern deciding means which decides the coincidence/discordance between the pattern to be checked and the dictionary pattern. CONSTITUTION:A prepared dictionary pattern is spirally scanned to a pattern to be checked and segmented out of the picture data inputted via a spiral scan processing means A. Then a scanning start point position correcting means B corrects the spiral scanning start point of the means A to a position nearest to the pattern to be checked when the scanning position of the dictionary pattern reaches the position nearest to the pattern to be checked. A pattern deciding means C decides the coincidence or moncoincidence between the pattern to be checked and the dictionary pattern based on the number of discrepant bits between both patterns. As a result, the matching scanning frequency is reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a pattern recognition device that recognizes patterns of characters, numbers, symbols, etc. through spiral scanning processing, the present invention aims to shorten the time required for pattern recognition by reducing the number of matching scans. A pattern recognition device that performs pattern recognition by pattern matching a pattern to be inspected cut out from input image data with a dictionary pattern prepared in advance; spiral scanning processing means for scanning in a circular pattern, and when the scanning position of the dictionary pattern comes to a close position of the pattern to be inspected, correcting the starting point of the spiral scanning by the spiral scanning processing means to the close position; The apparatus is configured to include a scanning starting point position correcting means, and a pattern determining means for determining whether the pattern to be inspected matches or does not match based on the amount of mismatched bits between the pattern to be inspected and the dictionary pattern.

[Industrial application field]

The present invention relates to a pattern recognition device, and more particularly to a pattern recognition device that recognizes patterns such as letters, numbers, and symbols by spiral scanning processing.

Currently, visual inspections of various products, such as checking whether the correct key top is inserted on the keyboard or whether the correct model number IC is mounted on the printed circuit board, are carried out as follows:
There is a shift from visual inspection to automatic inspection. However, when performing automatic inspection, there are problems such as product positioning and misalignment of patterns (letters, numbers) written on the product, and there is a need for a device that can recognize these patterns quickly and with high precision. .

[Conventional technology]

FIG. 6 is a block diagram showing an example of a conventional pattern recognition device. As shown in the figure, the conventional pattern recognition device includes an imaging system 10L, an A/D conversion circuit 102, a frame memory circuit 103, a pattern extraction circuit 104, a dictionary memory circuit 105, a matching position scanning circuit 106, and a pattern matching circuit. 107, a determination circuit 110, and a result output circuit 111.

The imaging system 101 takes an image of the inspection target using a camera, and the analog image signal from the imaging system 101 is sent to the A/
The data is digitized by the D conversion circuit 102 and stored in the frame memory circuit 103. Frame memory circuit 1
The image data stored in 03 is sent to the pattern cutting circuit 10.
4, a predetermined pattern to be inspected is cut out from the pattern and supplied to the matching position scanning circuit 106. Also,
A dictionary pattern previously stored in the dictionary memory circuit 105 is also supplied to the matching position scanning circuit 106, and the matching position scanning circuit 106 scans the pattern matching position between the pattern to be inspected and the dictionary pattern. .

Pattern matching between the extracted pattern to be inspected and the dictionary pattern is performed in a pattern matching circuit 107, and a determination circuit 110 determines whether the pattern matches or does not match based on the amount of unmatched bits calculated by the pattern matching circuit 107. That will happen.

The output from the determination circuit 110 is then output from the result output circuit 1.
11, and the determination result is output from the result output circuit 111. Here, the output signal of the determination circuit 110 is supplied to the matching position scanning circuit 106, and the pattern matching positions of the dictionary pattern with respect to the pattern to be inspected are sequentially scanned in a spiral manner.

FIG. 7 is a diagram for explaining spiral scanning processing in the pattern recognition device. As shown in the figure, in the spiral scanning process in the conventional pattern recognition device, the center of the cutout frame is set as the initial point P1 within the cutout frame of the pattern to be inspected cut out by the pattern cutout circuit 104. A matching position scanning circuit 106 scans the dictionary pattern in a spiral around the pattern.

At each matching position, pattern matching circuit 1
The amount of mismatched bits M calculated in step 07 is determined by the determination circuit 110.
is compared with the match determination level S, and if M>S, the matching position is shifted in the spiral scanning order, and then M
If a position (P3) where ≦S exists, the result output circuit 111 outputs a pattern matching recognition result at that point. Here, as a result of scanning the entire area within the cutting frame, M≦
If there is no position corresponding to S, a recognition result of pattern mismatch will be output from the result output circuit 111.

[Problem to be solved by the invention]

As described above, conventional pattern recognition devices perform pattern recognition by performing spiral scanning processing.

By the way, in the conventional pattern recognition device, the dictionary pattern is spirally scanned to the matching position P3 where the mismatch bit amount M calculated by the pattern matching circuit 107 satisfies M≦S with respect to the matching judgment level S of the judgment circuit 110. In this case, as shown in FIG. 8, if the distance from the center of the cutting frame (initial point P.) to the matching position P3 is 2, the total number of scans N is N# (2ffi+1)''.

As a result, in the conventional pattern recognition apparatus, for example, the pattern to be inspected is located at the initial point P of spiral scanning. There is a problem in that the further the pattern is deviated from the center of the clipping frame, the more the search area is wasted and the number of matching scans increases, resulting in an increase in matching processing time (time required for pattern recognition).

SUMMARY OF THE INVENTION In view of the problems of the conventional pattern recognition apparatus described above, it is an object of the present invention to reduce the number of matching scans and shorten the time required for pattern recognition.

[Means to solve the problem]

FIG. 1 is a block diagram showing the principle of a pattern recognition device according to the present invention.

According to the present invention, there is provided a pattern recognition device that performs pattern recognition by pattern matching a pattern to be inspected cut out from input image data with a dictionary pattern prepared in advance, wherein spiral scanning processing means A that spirally scans the pattern;
scanning starting point position correction means B for correcting the starting point of the spiral scan by the spiral scanning processing means A to the closest position when the scanning position of the dictionary pattern comes to the closest position to the pattern to be inspected; There is provided a pattern recognition device characterized by comprising a pattern determination stage C for determining coincidence/mismatch based on the amount of mismatch bits between the pattern to be inspected and the dictionary pattern.

[For production]

According to the pattern recognition device of the present invention, the spiral scanning processing means A spirally scans the pattern to be inspected cut out from the input image data using a dictionary pattern prepared in advance. Furthermore, when the scanning position of the dictionary pattern comes to the closest position to the pattern to be inspected, the scanning starting point position correcting means B corrects the starting point of the spiral scanning by the spiral scanning processing means A to the nearest position. is being used.

Then, the pattern determining means C determines whether the pattern to be inspected matches or does not match based on the amount of mismatched bins between the pattern to be inspected and the dictionary pattern. Thereby, the number of matching scans can be reduced and the time required for pattern iF6 can be shortened.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pattern recognition device according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the pattern recognition device of the present invention. As shown in the figure, the pattern recognition device of this embodiment includes an imaging system 1, an A/D conversion circuit 2, a frame memory circuit 3, a pattern extraction circuit 4, a dictionary memory circuit 5, a matching position scanning circuit 6, It includes a pattern matching circuit 7, a determination discrimination circuit 8, a scanning starting point position correction circuit 9, a determination circuit 10, and a result output circuit 1l.

The imaging system 1 is for taking an image of the inspection object with a camera, and the analog image signal from the imaging system 1 is digitized by the A/D conversion circuit 2 and sent to the frame memory circuit 3.
is stored in A predetermined pattern to be inspected is cut out from the image data stored in the frame memory circuit 3 by a pattern cutting circuit 4 and supplied to a matching position scanning circuit 6. Further, the matching position scanning circuit 6 is also supplied with a dictionary pattern stored in the dictionary memory circuit 5 in advance, and the pattern matching position between the pattern to be inspected and the dictionary pattern is scanned in a spiral manner by the matching position scanning circuit 6. It is done like this.

Pattern munching processing between the extracted pattern to be inspected and the dictionary pattern is performed in a pattern munching circuit 7, which calculates matching bits and mismatching bits between the pattern to be inspected and the dictionary pattern. The judgment discrimination circuit 8 switches the output signal to the scan starting point position correction circuit 9 and the judgment circuit 10 according to the amount of mismatched bits calculated by the pattern matching circuit 7.

The scanning starting point position correction circuit 9 includes a pattern matching circuit 7
When the amount of mismatched bits M calculated in is equal to or less than a predetermined value S' (S+t) with a certain margin (1), the position of the starting point for spiral scanning is determined by the amount of mismatched bits. The position is corrected to the position that is below the value (described in detail later with reference to FIG. 5), and the position information to be corrected is supplied from the scanning starting point position correction circuit 9 to the matching position scanning circuit 6. being done.

The determination circuit 10 is similar to a conventional pattern recognition device, and determines whether the pattern matches or does not match based on the amount of unmatched bits calculated by the pattern matching circuit 7. The output from the determination circuit 10 is supplied to the result output circuit l1, and the determination result is output from the result output circuit l1.

Here, the output signal of the determination circuit 10 is supplied to the masocing position scanning circuit 6, as in the conventional pattern recognition device, so that the pattern matching position of the dictionary pattern with respect to the pattern to be inspected is sequentially scanned in a spiral manner. ing.

In this way, in the pattern recognition device of this embodiment,
First, the matching position scanning circuit 6 and the pattern matching circuit 7 perform spiral scanning similar to the conventional method with the center of the cutting frame as the starting point, and determine the degree of masoching (for example, the amount of mismatched bits) at that scanning position. is supplied from the pattern matching circuit 7 to the judgment discrimination circuit 8. Then, when the judgment discrimination circuit 8 determines that the dictionary pattern is a semi-matching state to the pattern to be inspected (a state in which the scanning position of the dictionary pattern is in the closest position to the pattern to be inspected), the scanning initial point position is corrected. The starting point position of the spiral scan is corrected by the circuit 9 and the manoching position scanning circuit 6 so that the closest position becomes the new starting point, and a new spiral scan is performed from the new starting point position. Then, the munching result from the pattern munching circuit 7 is switched by the judgment discrimination circuit 8 so as to be supplied to the judgment circuit 10, and the judgment circuit 10 judges whether it is a match or a mismatch. As a result, it is possible to omit scanning in a wasteful area (spiral scanning in the upper right area in FIG. 8), which is performed in conventional pattern recognition devices, and reduce the number of matching scans of the dictionary pattern with the pattern to be inspected. This makes it possible to shorten the time required for pattern recognition.

FIG. 3 is a diagram showing an example of an object to be inspected to which the present invention is applied.

The pattern recognition device of this embodiment is used, for example, to inspect the appearance of a keyboard 31 as shown in FIG.
2 number r8J position) at the correct key top (for example,
This is used to check whether the number F8J (Keatsoap) has been inserted.

FIG. 4 is a diagram showing an example of a pattern to be inspected cut out from the frame memory circuit.

For example, when performing an external appearance inspection of the keyboard 3l using the pattern recognition device of this embodiment, first, an image of the entire keyboard or a predetermined range is taken by the imaging system 1, and this image signal is sent to the A/D conversion circuit 2. The data is digitized and stored in the frame memory circuit 3.

Then, for example, on the numeric keypad 32 of the keyboard 3l, the pattern cutting circuit 4 cuts out the image data of the area where the key top of the number F8J is to be inserted. Here, the number ['3J] engraved on the key top would ideally be located in the center of the cutout frame, but in reality,
As shown in FIG. 4, it is often not located at the center of the cutting frame due to misalignment between the imaging system 1 and the keyboard.

In the case of FIG. 4, it is biased towards the lower left position of the cutting frame. At this time, pattern matching is performed by spirally scanning the dictionary pattern against the extracted pattern to be inspected, but the pattern recognition device of the present invention further reduces the number of spiral scans required for pattern recognition. In order to further reduce the processing time, when the amount of mismatched bits calculated by the pattern matching circuit 7 falls below a predetermined value with a certain margin, that is, when the dictionary pattern is close to the pattern to be inspected, When the determination discrimination circuit 8 determines that there is a half match, the starting point for spiral scanning is corrected to the position where the amount of mismatched bits is less than a predetermined value.

FIG. 5 is a diagram for explaining processing operations in the pattern recognition device of the present invention.

As described with reference to FIG. 2, for example, the keyboard to be inspected (see FIG. 2) is input as an analog signal by the imaging system 1, and the analog image signal is sent to the A/D
The data is digitized by the conversion circuit 2 and stored in the frame memory circuit 3. The pattern cutting circuit 4 cuts out the pattern to be inspected from the frame memory circuit 3 (see FIG. 4). The matching position scanning circuit 6 first sets the center P1 of the cutting frame as the matching position (starting point of spiral scanning),
Pattern matching circuit 7 performs pattern matching with the dictionary pattern read out from dictionary memory circuit 5.

The no-lose bint amount M calculated by the pattern matching circuit 7 is supplied to the judgment discrimination circuit 8, and is given a margin of 1 (1 differs depending on the dictionary pattern) than the match judgment level S that judges one-lose/unmatched. The added value S' (here, S"
1S+t). Here, the determination based on the value S' of the mismatch bit amount M may not be performed by the determination discrimination circuit 8, but may be configured to be performed by providing a pre-determination circuit in front of the scanning starting point position correction circuit 9. Further, the value S' is not a pattern match, but is at a level of a semi-match (close to a match).

In the judgment discrimination circuit 8, if the mismatch bit amount M〉S゛, that is, they do not match at all, the scan starting point position correction circuit 9 does not correct the spiral scanning direction, and the process is performed in the same way as in the conventional pattern recognition device. Next, pattern matching is performed while performing spiral scanning using the matching position scanning circuit 6. On the other hand, in the judgment discrimination circuit 8, if there is a position P2 where the mismatch bit amount M≦S゛,
That is, when the dictionary pattern position approaches the pattern to be inspected, the scanning initial point position correction circuit 9 changes the position i P z (vertical distance m from the initial point P1) into a spiral as shown in FIG. As a new starting point of the spiral scan, the scan direction is modified to perform a new spiral scan. The mismatch bit amount M' obtained by performing a new spiral scan from the initial point P2 by the matching position scanning circuit 6 is supplied from the judgment discrimination circuit 8 to the judgment circuit 10, and is compared and judged with the match judgment level S. .

In the determination circuit 10, the mismatch bit amount M゛ is M゛〉S
, that is, if the patterns do not match, scanning is continued. If there is a position P3 (vertical distance l from the initial point P1) where the amount of mismatched bits M≦S exists, that is, if the dictionary pattern and the pattern of the object to be inspected match, the result output circuit 11 outputs the pattern Matches are printed. Also, the entire inside of the cutting frame is scanned, and M≦S (M
' ≦S), the result output circuit 11
A pattern mismatch is output.

As shown in FIG. 5, the number of matching scans N' in the pattern recognition device of this embodiment is from the center of the cutting frame (the starting point of the first spiral scan) P to the starting point P2 of the new spiral scan. m, the vertical distance from the new starting point P2 to the pattern position P3 is n (here,
l = m + n), the total number of scans N'' is N'
# (2m+1)20(2n±1)2-1. Here, the total number of scans N in the conventional pattern recognition device is N
′＝． (2f+1)2-(2 (m+n)+1)2, so the difference is N-N' 8mn. Therefore, in the pattern recognition apparatus of this embodiment, the number of matching scans can be reduced by about 8 mn times, and the time required for pattern recognition can be shortened.

[Effects of the Invention] As explained above, according to the pattern recognition device of the present invention, when the scanning position of the dictionary pattern comes to the closest position to the pattern to be inspected, the starting point of the spiral scan is corrected to the closest position. However, by performing the spiral scan again from there, it is possible to reduce the number of matching scans and shorten the time required for pattern recognition.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the principle of a pattern recognition device according to the present invention, FIG. 2 is a block diagram showing an embodiment of the pattern recognition device according to the present invention, and FIG. 3 is a block diagram showing an example of an inspection target to which the present invention is applied. FIG. 4 is a diagram showing an example of a pattern to be inspected cut out from a frame memory circuit. FIG. 5 is a diagram for explaining the processing operation in the pattern recognition device of the present invention. FIG. 6 is a conventional A block diagram showing an example of a pattern recognition device, FIG. 7 is a diagram for explaining spiral scanning processing in a pattern recognition device, and FIG. 8 is a diagram for explaining processing operations in a conventional pattern recognition device. be. (Explanation of symbols) A... Spiral scanning processing means, B... Scanning initial point position correction means, C... Pattern determination means, 1... Imaging system, 2... A/D conversion circuit , 3... Frame memory circuit, 4... Pattern cutting circuit, 5... Dictionary memory circuit, 6... Munching position scanning circuit, 7... Pattern munching circuit, 8... Judgment discrimination Circuit, 9... Scanning initial point position correction circuit, lO... Judgment circuit, 11... Result output circuit. Figure matching position for explaining the cutout frame 8 M

Claims (1)

[Claims] 1. A pattern recognition device that performs pattern recognition by pattern matching a pattern to be inspected cut out from input image data using a dictionary pattern prepared in advance, the device comprising: spiral scanning processing means (A) for spirally scanning the dictionary pattern; and when the scanning position of the dictionary pattern comes close to the pattern to be inspected, the spiral scanning processing means (A) starts spiral scanning by the spiral scanning processing means. scanning starting point position correcting means (B) for correcting a point to the closest position; and pattern determining means (B) for determining whether there is a match or mismatch between the inspected pattern and the dictionary pattern based on the amount of mismatched bits between the pattern to be inspected and the dictionary pattern.
C) A pattern recognition device comprising: 2. The scanning initial point position correcting means (B) adjusts the scanning position of the dictionary pattern when the amount of mismatched bits between the pattern to be inspected and the dictionary pattern becomes less than or equal to a predetermined value with a certain margin. 2. The pattern recognition apparatus according to claim 1, wherein the starting point of said spiral scanning is corrected when said pattern has come close to said pattern to be inspected. 3. An imaging system (1) that captures images of the inspection target, an A/D conversion circuit (2) that digitizes analog image signals from the imaging system, and stores digital signals from the A/D conversion circuit. a frame memory circuit (3) for extracting a pattern to be inspected from the frame memory circuit; a pattern extraction circuit (4) for extracting a pattern to be inspected from the frame memory circuit; and a dictionary memory circuit in which a dictionary pattern to be compared with the extracted pattern to be inspected is stored in advance. (5); and a matching position scanning circuit (6) that scans a pattern matching position between the pattern to be inspected and the dictionary pattern.
and a pattern matching circuit that performs pattern matching between the extracted pattern to be inspected and the dictionary pattern (
7); a determination discrimination circuit (8) that switches an output signal according to the amount of mismatched bits calculated by the pattern matching circuit; a scan starting point position correction circuit (9) that corrects the starting point position for spiral scanning to the position where the amount of mismatched bits becomes less than a predetermined value when the amount of mismatched bits becomes less than a predetermined value; A determination circuit (10) that determines whether there is a match or a mismatch based on the amount of mismatched bits calculated by the pattern matching circuit, and a result output circuit (10) that outputs the determination result of the determination circuit.
1) A pattern recognition device comprising: