JPH0210990B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line recognition device that recognizes solid lines, broken lines, and chain lines used in various types of graphics in a pattern recognition device that recognizes graphic patterns.

In various design drawings, the meanings of lines are given by changing the type of lines, such as solid lines, broken lines, chain lines, etc. Therefore, in order to recognize such design drawings, it is necessary to recognize broken lines, chain lines, etc. as a single connected line.

Figure 1 shows the drawing to be recognized, with line figures ABCD drawn in solid lines and line figures drawn in broken lines.
EFGH, line figure IJKL written with a dashed-dotted line 2
In Fig. 2, each line figure is
Consider recognizing them as line figures ABCD, EFGH in Figure 3, and IJKL in Figure 4.
In order to perform the above recognition process using a coordinate reading device connected online to a computer, a human must first identify a line figure drawn with a solid line, a line figure drawn with a broken line, and a line figure drawn with a dot-dashed line. It is necessary for the human being to perform a series of operations such as distinguishing and recognizing each line figure, and then storing the coordinate values in the computer while moving the coordinate reading index to the position of the end point or bending point of the line figure. Ta.

The present invention relates to a pattern recognition device that automatically recognizes figures including solid lines, broken lines, or chain lines.

In order to achieve this purpose, the present invention includes a solid line route recognition device that recognizes solid lines in a figure, and also recognizes each line segment that makes up a broken line as an individual solid line. A broken line route recognition device that compares and connects the end point positions of the line segments that have been created is further added.

Therefore, the solid line route recognition device can recognize solid lines, the broken line route recognition device can recognize broken lines, and it is possible to recognize figures including solid lines and broken lines. Furthermore, since the solid line route recognition device serves both solid line recognition and line segment end point detection, the device configuration is simplified.

Hereinafter, the present invention will be explained in detail with reference to Examples. In Figure 1, the line figure drawn with a broken line
In order to recognize EFGH as EFGH in Figure 3, and to recognize the line figure IJKL drawn with dashed lines in Figure 1 as IJKL in Figure 4, it is necessary to It is necessary to trace line segments along the direction. FIG. 5 is a block diagram showing the overall configuration of a pattern recognition device according to the present invention, which will be explained step by step below.

In FIG. 5, 1 is a drawing to be recognized, 2 is a photoelectric conversion device, 3 is an image memory, 4 is a solid line route recognition device, 5 is a feature point storage memory, 6 is a broken line route recognition device, and 7 is a neighborhood candidate limiting circuit. , 8 is a connection candidate storage memory, 9 is a direction determination circuit, 10 is a connection determination circuit, and 11 is a connection information storage memory.

In such a configuration, the photoelectric conversion device 2 such as a television camera converts the image information of the drawing 1 to be recognized as shown in FIG. 1 into a binary electric signal, and temporarily stores it in the image memory 3. Next, the solid line route recognition device 4 recognizes the solid line route from the information stored in the image memory 3, extracts the feature points of the solid line, specifically the coordinates of the end points and bending points, and extracts the coordinates of the feature point storage memory. Store in 5. Here, each line segment forming a dashed or chain line is stored as a single solid line. This inner solid line route recognition device 4 can be realized by applying a line thinning method used in character reading devices, etc., and can be realized by, for example, the one shown in Japanese Patent Publication No. 38-21255.

In the broken line route recognition device 6 according to the present invention, the neighbor candidate limiting circuit 7 determines the end point coordinates of a specific line segment stored in the feature storage memory 5, for example.
Using the first stored end point coordinates as the base point coordinates, calculate the distance to each end point of each line segment around the base coordinates, and if the distance is smaller than a certain threshold, use the end point coordinates as a neighbor candidate. , on the line segment to which the end point coordinates belong, are transferred to the connection candidate storage memory 8 along with the coordinates of other end points or bending points adjacent to the end point coordinates, and at the same time, the value of the base point coordinates stored in the memory 5 and the base point coordinates are transferred to the connection candidate storage memory 8. The end point or bending point coordinates adjacent to the base point coordinates on the line segment to which the base point belongs are also stored in the memory 8.
Transfer to. Next, in the direction determination circuit 9, from these coordinates stored in the connection candidate storage memory 8,
The vector of the line segment to which the base point coordinates belong, the vector from the base point coordinates to the neighboring candidate point coordinates, and
The connection determination circuit 10 calculates the angles that the vector to which the coordinates of the adjacent candidate points belong and the reference vector (here, the horizontal axis) and determines whether these angles are less than a certain reference value. It is determined whether or not both line segments should be connected, and the result is stored in the connection information storage memory 11.

FIG. 6 shows an example of a specific configuration of the neighboring candidate limiting circuit 7 in the broken line route recognition device 6 in FIG. 5, in which 21 and 22 are selectors, 23 to 28 are registers, 29 and 30 are comparators, 31 and 32 are threshold circuits, 33 to 38 are AND gates, and 39
4 is an address bus, 40 is a data bus, 41 is a control bus, and 42 is a central processing unit (CPU).

When segment video information as shown in FIG. 7 is input from the photoelectric conversion device 2, data as shown in FIG. 8 is stored in the feature point storage memory 5 through recognition by the solid line route recognition device 4. . That is, for each line segment _L1 to _L3 , the number of segment constituent points, starting point and ending point information, and information on the starting point, bending point, and ending point coordinates are stored in the memory 5.

Among these, the number of segment constituent points represents the number of end points and bending points, and the start point and end point information represent flags attached to the start point coordinates and end point coordinates, respectively, as will be described later.

The contents of such feature point storage memory 5 are as follows:
It is read out according to the address on the address bus 39 set by the CPU 42. Its contents are classified by selector 21 and selector 22 via data bus 40. Now, BP represents the coordinates of the search base point, and BP-1 represents the coordinates of the end point or bending point adjacent to the coordinate BP on the line segment to which the base point coordinate BP belongs. CP ₁ is the candidate point coordinates on the starting point side of the power line segment to be searched, CP ₁ -1 is the coordinates of the end point or bending point adjacent to the coordinate CP ₁ on the line segment to which the coordinate CP ₁ belongs, and CP ₂ is the end point side The candidate point coordinates, CP ₂ -1, represent the coordinates of the end point or bending point adjacent to the coordinate CP ₂ on the line segment to which the coordinate CP ₂ belongs. The selector 21 operates when the address bus 39 is the address of a point corresponding to the coordinates BP and BP-1, and the coordinates BP is stored in the register 23.
Then, the coordinate BP-1 is stored in the register 24.
On the other hand, the selector 22 operates when the address bus 39 is the address of the point corresponding to the coordinates CP ₁ , CP ₁ -1, CP ₂ , CP ₂ -1, and the coordinate CP ₁ is the register 2
5. Coordinate CP ₁ -1 is in register 26, coordinate CP ₂ is in register 27, and coordinate CP ₂ -1 is in register 28.
are stored respectively. In the comparison circuit 29, the coordinates
Calculate the distance between BP and CP ₁ , that is, the value E ₁ = |BP−CP ₁ |. On the other hand, in the comparison circuit 30, E ₂ =|
Calculate the value of BP−CP ₂ |. The threshold circuit 31 issues an ON signal when the calculated value E ₁ is smaller than a pre-stored parameter ε for setting a neighboring area. Similarly, the threshold circuit 32 issues an ON signal when the calculated value E ₂ is smaller than the parameter ε. The signals of these threshold circuits 31 and 32 are subjected to AND logic with the values of registers 25 to 28 by AND gates 35 to 38, and input to connection candidate storage memory 8 is restricted. The address of the connection candidate storage memory 8 is set by the CPU 42 via the address bus 39. As a result, the connection candidate storage memory 8 contains BP, BP-1, CP _i , CP _i -1 (i=1 or 2).
will be stored sequentially. Similarly, the coordinates
Keeping BP and BP−1 fixed, move to the next line segment
The above operation is performed by setting CP _i and CP _i -1.

After performing the operation of connecting the search base point of the i-th line segment end point and the corresponding connection candidate point, in order to trace the line segment that is continuous with it, the (i+1)th search base point is connected to the i-th connection candidate point. Move the point on the line segment where the candidate exists to the end point adjacent to the connection candidate. The necessary conditions for a point to be a search base point are the same as the setting conditions for the search base point in the previous section, and the point must not have any flags attached to either end point information or coordinate values. If you are trying to set a point that has already been flagged as the next search base point, the segment that makes up the dashed line or chain line must reach an isolated end point, or if the segment is a loop-like line with no isolated end points. This is the case when the segments are lined up.

FIG. 9 shows an example of a specific configuration of the direction determination circuit 9 and the connection determination circuit 10 in the broken line route recognition device 6 of FIG.
3 to 56 are registers, 57 to 59 are calculation circuits, 6
0 to 62 are threshold circuits, 63 to 65 are AND gates, and 66 is a latch circuit.

Before explaining the operation of such a circuit,
The principle of selecting connectable candidate points will be explained.

If only one neighboring candidate point coordinate CP appears in the search area as shown in FIG. 10, the coordinate CP is a candidate that can be connected to this search base point. On the other hand, if there are a plurality of neighboring candidate point coordinates CP that appear within the search area, conditions for connection are investigated. That is, as shown in FIG. 11, the point on the segment where the search base point coordinate BP exists, the point adjacent to the coordinate BP is the coordinate BP-1, and the point on the line segment where the connection candidate point coordinate CP exists, If the point adjacent to the coordinate CP is the coordinate CP-1, then the coordinates BP, BP-1,
Check whether the four points CP and CP-1 are lined up in a straight line. If there is only one point that satisfies the four-point straight-line condition as shown in Figure 11, the coordinates CP of that point are used as a connectable candidate point, and the four-point straight-line condition is established as shown in Figure 12. If there are multiple satisfying points, the distance between the coordinates BP and CP is calculated, and the coordinate CP with the smaller distance is selected as a connectable candidate point. On the other hand, as shown in FIG. 13, if there are a plurality of neighboring candidate points and there is no point that satisfies the linear condition, a connection failure flag is attached to the coordinates CP and BP that appear in the minute area. Furthermore, if there is no nearby candidate point in the minute region for searching for nearby candidates, an isolated point flag is added to the end point information of the search base point. The flow of the algorithm for selecting connectable candidates is shown in FIG.

It is assumed that the address of the connection candidate storage memory 8 is set by the CPU 42 via the address bus 39 based on the output of the adjacent candidate limiting circuit 7. The contents are classified by selectors 51 and 52 via data bus 40. The selector 51 is activated by a signal from the CPU 42 to the control bus 41 when the data on the data bus 40 is the address of a point corresponding to the coordinates BP and BP-1. 54. On the other hand, the selector 52 is activated by a control signal when the data on the data bus 40 is an address of a point corresponding to the coordinates CP and CP-1.
CP is in register 55. CP-1 is in register 56.
is memorized. Calculation circuits 57 to 59 are circuits that calculate the angle that a line segment formed by two points makes with a reference vector (in this case, the horizontal axis). For example, if the coordinates of two points are (X ₁ , Y ₁ ), (X ₂ , Y ₂ ), then Δ=(X ₂ −X ₁ ) ² /(X ₂ −X ₁ ) ² +(Y ₂ −Y ₁ ) Do the calculation of ² . (This means the square of the inner product.)
The calculation circuit 57 performs this calculation on the coordinates BP and BP-1, and the calculation circuit 58 performs this calculation on the coordinates BP-1.
This calculation is performed for BP and CP, and the calculation circuit 59 performs this calculation for the coordinates CP and CP-1. Then, let each calculated value be Δ _BpBp-1 Δ _BpCp Δ _CpCp-1 .

Threshold circuits 60 to 62 generate ON signals when the value just calculated is smaller than a certain value. The threshold circuit 60 issues an on signal when Δ _BpBp-1 is smaller than a constant value ε, the threshold circuit 61 issues an on signal when Δ _BpCp is smaller than the fixed value ε, and the threshold circuit 62 issues an on signal when Δ _BpBp- 1 is smaller than a constant value ε. It emits an on signal when ₁ is less than a certain value ε. The outputs of these three threshold circuits 60 to 62 are connected to the gate 6.
3 is used to gate the storage of the coordinates BP and CP in the latch circuit 66. That is, the coordinates BP and CP stored in the latch circuit 66 are a pair of connectable points.

As described above, according to the present invention, a figure drawn with a broken line or a chain line in a drawing can be automatically recognized while being traced.

[Brief explanation of drawings]

1 to 4 are explanatory diagrams of drawings to be recognized, FIG. 5 is an overall configuration diagram of an example of a pattern recognition device according to the present invention, and FIG. 6 is a specific configuration of the proximity candidate limiting circuit shown in FIG. 5. FIG. 7 and FIG. 8 are explanatory diagrams for explaining FIG. 6; FIG. 9 is a configuration diagram of an example of a specific configuration of the direction determination circuit and connection determination circuit of FIG. 5; 10 to 14 are diagrams showing the principle of selection of connectable candidate points according to the present invention. 6: Broken line route recognition device, 7: Neighborhood candidate limiting circuit, 9: Direction determination circuit.

Claims (1)

[Scope of Claims] 1. A pattern recognition device that recognizes a figure including a solid line and a broken line or a chain line, comprising: a photoelectric conversion means that converts an image of the figure into an image signal; solid line route recognition means for detecting the end point positions of the line segments constituting the line segment, and comparing the end point positions of each line segment with the end point positions of other line segments among the detected end point positions, A pattern recognition device comprising a broken line route recognition means for determining and connecting power line segments.