JPH0226261B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a matching maximum point detection device that is required when recognizing the positions of a plurality of patterns using pattern matching without contact.

BACKGROUND OF THE INVENTION In recent years, the demand for pattern recognition in industries to detect the position of objects without contact has been increasing, and some patterns are being used in semiconductor assembly processes. Hereinafter, position recognition by conventional pattern matching as described above will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a conventional position recognition method using pattern matching. In FIG. 1, 1 is an imaging device, 2 is a synchronization signal generation circuit for driving the imaging device 1, 3 is a coordinate generation circuit for obtaining the position of the scanning beam, and 4 is the imaging device 1
5 is a temporary storage circuit consisting of a shift register; 6 is a preprocessing circuit consisting of a circuit that binarizes the video signal from 5; 6 is a temporary storage circuit for cutting out patterns used for matching degree detection in parallel from among the patterns stored in the temporary storage circuit 5; 7 is a standard pattern storage circuit that stores pre-registered patterns in a form that allows for the degree of matching to be detected; 8 is a standard pattern storage circuit 7 that stores the patterns cut out by the 2D pattern extraction circuit 6; 9, a coincidence degree storage circuit that stores the degree of coincidence; 10, a comparison circuit that compares the degree of coincidence; 11;
12 is a gate circuit that transmits the degree of coincidence output from the degree of coincidence detection circuit 8 to the degree of coincidence memory circuit 9; 12 is a gate circuit that conveys the coordinates output from the coordinate generation circuit 3 to the coordinate memory circuit; 13 is a gate circuit that transmits the coordinates of the scanning beam; This is a coordinate storage circuit that stores coordinates.

The operation of the position recognition method using pattern matching configured as described above will be explained below. First, an object such as a semiconductor chip is converted into a video signal by the imaging device 1. The scanning beam at this time is synchronized with the synchronization signal generated by the synchronization signal generation circuit 2, and its coordinates are always obtained from the coordinate generation circuit 3. Next, the video signal is converted by a preprocessing circuit 4 into a binary signal that can be easily handled by a cooking circuit, and is input to a temporary storage circuit 5 consisting of a shift register. The next two-dimensional pattern cutting circuit 6 from this
Depending on the image information, the horizontal and vertical size (for example, 16
x 16 pixels) is sequentially read out as rectangular pattern information. The matching degree detection circuit 8 compares the pattern cut out by the two-dimensional pattern cutting circuit 6 and the standard pattern stored in the standard pattern storage circuit 7 to detect the degree of matching. The detected degree of coincidence is compared with the degree of coincidence stored in the past in the degree of coincidence memory circuit 9 in the comparison circuit 10, and when the degree of coincidence detected is greater, the gate circuit 11 is opened and the contents of the degree of coincidence memory circuit 9 are compared. Update. The output of the comparison circuit 10 is further sent to the gate circuit 12, and the coordinate values of the scanning beam at that time are guided to the coordinate storage circuit 13, thereby updating the previously stored coordinate values.

Repeating this operation, at the final point in the frame when scanning ends, the coordinate position X, Y in the image where the pattern that most closely matches the pre-stored standard pattern exists is stored and retained along with the degree of matching at that time. .

Problems to be Solved by the Invention However, with the above configuration, only one point is detected where the pattern most closely matches, and if there are multiple shape patterns similar to the target partial pattern, only one of them is detected. This method has a problem in that it is not known which partial pattern to detect.

In view of the above problems, the present invention provides a matching maximum point detection device for detecting all of a plurality of shape patterns similar to a target partial pattern on an image capturing screen.

Means for Solving the Problems In order to solve the above-mentioned problems, the matching maximum point detection device of the present invention corresponds the matching degree of a partial pattern whose representative position is an area of at least 3×3 pixels with its positional relationship. and a means for temporarily storing the central position, and when the matching degree of the partial pattern with the center position as the representative position is not smaller than the matching degree of the partial pattern with the adjacent neighborhood as the representative position, the central position is set to the maximum matching degree. A point is determined as a point, and means is provided that does not cause redundant local maximum point determination even if the matching degree is the same as that of a partial pattern whose representative position is an adjacent neighborhood.

Effects According to the present invention, even if a plurality of similar shape patterns exist on the imaging screen, the maximum matching point can be obtained for each pattern, and the recognition of the plurality of points can be achieved by pattern matching. It is possible to do so.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a pattern recognition method in one embodiment of the present invention. In FIG. 2, 20 is the pattern matching circuit shown in FIG. 1, 21 is a temporary storage circuit that temporarily stores the degree of matching output from the pattern matching circuit 20, and 22 is a circuit around a certain point on the screen. 8-neighborhood extraction circuit that extracts the degree of coincidence for 8 pixels, 23a to 23h
24 is a circuit that compares the degree of coincidence with the 8 neighboring points, and 24 is a maximum point determination circuit that determines whether or not it is a maximum point based on the comparison result.

The operation of the pattern recognition method configured as described above will be explained below.

Assume that when the object is scanned for one frame, the degree of matching output from the pattern matching circuit 20 is expressed as shown in FIG. In Figure 3, a
Points are points that should be correctly recognized, point b is a point shifted by one pixel from point a, and point c is a point that should be correctly recognized. This state will be further explained with reference to FIG. 1 in FIG. 4 is a standard pattern, and the screen is scanned using this pattern to detect the degree of coincidence at each point. 1 in Figure 4 is the standard pattern, and 4 is the third pattern.
In the example of the pattern at point c in the figure, the pattern should be correctly recognized, but because the pattern at part A is missing, the degree of matching is 80/100, which is from point a to c.
The smallest of the points. 2 and 3 in FIG. 4 are examples of the patterns of points a and b in FIG. 3, respectively, where 2 has a matching degree of 91/100 and 3 has a matching degree of 88/100.

In this example, we want to detect the a key and the c point, but if we select two candidate points in descending order of degree of matching, a
Only point and point b are detected, and point c is not detected. In order to detect point c as the second recognition point, it is necessary to detect the coordinates at which the degree of matching is maximum.

In FIG. 2, a pattern matching circuit 20
The degree of coincidence outputted from is stored in a temporary storage circuit 21 consisting of a shift register.

If it is assumed that the pixel B in Figure 4 represents the coordinate values of the standard pattern, then the degree of coincidence of each of the positions indicated by A to I in Figure 5 when B is scanned is the 8 neighborhood shown in Figure 2. It is cut out by the cutting circuit 22. The comparison circuits 23a to 23h and the maximum point determination circuit 24 in FIG. 2 compare the degree of coincidence of the extracted point E with the degree of coincidence of the surrounding points (eight neighboring points), and the following conditions are all satisfied. , it is determined that the degree of coincidence at point E is the maximum point.

E _er > A _er , E _er > B _er E _er > C _er , E _er > D _er E _er F _er , E _er G _er E _er H _er , E _er I _er , where A _{er is} the degree of agreement at point A and below B _er
~ _Ier represents the degree of agreement at each point.

When comparing the degree of agreement at points F to I with the degree of agreement at point E, even if the degree of agreement is equal, it is determined to be the maximum point, so if one point consecutive to point E has the same degree of agreement. To effectively determine a maximum point without missing the maximum point or detecting it redundantly.

As described above, according to this embodiment, the degree of coincidence obtained by pattern matching is temporarily stored, and the degree of coincidence of a partial pattern with the point of interest as the representative position and its 8 neighbors are determined as the representative position. Cut out the matching degree of the partial pattern and compare them, 8
If the three neighboring points in the top row and the left point in the middle row are set as the first group, and the others are set as the second group, the matching degree of the partial pattern with the point of interest as the representative position is larger than the matching degree of the partial pattern whose representative position is each point of the first group, and is greater than or equal to the matching degree of the partial pattern whose representative position is each point of the second group, then the point of interest is set as the maximum point. By determining this, it is possible to effectively detect the maximum matching point without duplication.

Effects of the Invention As described above, the present invention provides a means for temporarily storing the degree of coincidence of partial patterns whose representative positions are at least 3×3 pixel areas in association with their positional relationships;
When the matching degree of the partial pattern with the center position as the representative position is not smaller than the matching degree of the partial patterns with the adjacent neighborhood as the representative position, the center position is determined to be the maximum matching point, and By providing a means that does not cause redundant maximum point determination even if the matching value is the same as that of a partial pattern whose neighborhood is the representative position, the maximum matching point can be detected effectively, and multiple points can be displayed on the imaging screen. Even if similar shape patterns exist, all their positions can be detected.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of position recognition using conventional pattern matching, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing an example of changes in the degree of matching with respect to screen scanning. Figure 4 is a diagram showing the state of the pattern to more specifically explain the change in the degree of matching in Figure 3, and Figure 5 is a diagram showing the state of the pattern.
It is a diagram showing nearby points. 21... Temporary storage circuit, 22... 8 neighborhood extraction circuit, 23a to 23h... Comparison circuit, 24... Maximum point determination circuit.

Claims (1)

[Scope of Claims] 1. An imaging device for imaging an object, means for storing a pattern that is substantially the same as a plurality of parts of the object on an imaging screen obtained by the imaging device as a standard pattern; The method includes means for cutting out the partial pattern on the imaging screen, and means for comparing the standard pattern and the cut out partial pattern to calculate a degree of coincidence, and detecting a point at which the calculated degree of coincidence is maximum. A device for recognizing the positions of a plurality of similar shape patterns on the imaging screen, wherein the degree of coincidence of partial patterns having an area of at least 3×3 pixels as a representative position is temporarily stored in association with the positional relationship thereof. Then, when the degree of correspondence of the partial pattern whose representative position is the center position among the temporarily stored degrees of correspondence is not smaller than the degree of correspondence of the partial pattern whose representative position is its adjacent neighborhood, the degree of correspondence of the partial pattern at the center position is determined to be the maximum matching point, and the matching value of the partial pattern with the above center position as the representative position is the same as the matching degree of the partial pattern with its adjacent neighborhood as the representative position, but the overlapped maximum point is determined. A maximum coincidence point detection device having a means for preventing occurrence of 2. Even if the matching degree of a partial pattern whose representative position is the center position and the matching degree of a partial pattern whose adjacent vicinity is the representative position are the same value, the means to avoid duplicate local maximum point determinations is to 2
The degree of matching of the partial patterns divided and having the first adjacent neighborhood as the representative position is lower than the degree of matching of the partial patterns having the center position as the representative position, and the part having the second adjacent neighborhood as the representative position. A patent claim characterized in that the center position is determined to be the maximum point when the degree of matching of the patterns is either smaller than the degree of matching of partial patterns having the center position as a representative position, or when either of them is the same value. The device for detecting the maximum point of coincidence according to item 1.