JP2553039B2 - Drawing processing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing processing method, and in particular, drawing data digitized into a sequence of coordinates of break points or end points by linearly approximating a contour line of a figure and a thinning pattern. The present invention relates to a drawing processing method for obtaining connection information between symbols and arrangement information of drawings.

[Background of the Invention]

As the automation of design progresses, it is required to input the drawings such as the design drawings into the computer to obtain the connection information of the symbols of the predesignated shape such as the circle or the square described in the drawings. ing. Traditionally, CAD (Compu
ter Aided Design) is used to read the symbol connection information from the drawing. The method is (1) calculating the center line of the drawing and tracking the center line, or ( 2) Other methods such as tracing lines are used. In both cases, the trajectory is read by extracting the line of interest and tracing only that line. For example, Japanese Patent Application Laid-Open No. 60-48580 discloses a method of obtaining symbol connection information from a drawing drawn with a line having a predetermined width. However, in this case, it is a condition that the object of the drawing is a design drawing drawn on a blank sheet and that the size is constant. Therefore, it is possible to recognize connected symbols or automatically connect information between symbols in a design drawing etc. that has an indefinite size and is drawn by a filled figure (a figure filled in black as shown in FIG. 3). Could not be read. In order to obtain connection information between symbols from such a figure, it has conventionally been necessary to manually input information into a computer, which requires a lot of time for work.

[Object of the invention] The object of the present invention is to improve such conventional problems,
An object of the present invention is to provide a drawing processing method capable of obtaining arrangement information of a figure from a filled figure together with a symbol wiring diagram.

[Outline of Invention]

In order to achieve the above object, the drawing processing method of the present invention is characterized by performing processing according to the following algorithm using a process of recognizing a center line of a figure and a process of integrating the center lines. (A) First, at a branch point appearing on the center line, a line segment passing through this branch point is cut at that point, and branch information is added to the cut end point. (B) Eliminate lines where branch information is not added to both end points. as a result,
When a branch point is shared only by the end points of two line segments, midpoint information is added to the two branch end points. (C) Recognize the symbol and determine the center coordinates of the symbol. (D) A closed figure including the center point of the symbol as an inner point and constituted by the center line group is detected. Then, the number of times the center line is selected is added as a label to this pattern. If there is a center line passing near the center of the symbol, the center line is cut at the point closest to the center of the symbol, and the cutting point is drawn to the center of the symbol. (E) The closed figure is detected again. At this time, when the center line with the label of 2 is selected, a line segment is generated from the midpoint of the line with the symbol and the label of 0 added to the center, and the symbol information is attached to the end point on the symbol side. , Integrated information is added to each end point on the middle point side. The line segment is the same type as the center line. A line segment connecting the centers of the symbols is generated from the branch point passing when tracing the line segment. Then, when only the line segments to which the label of 0 or 1 is added are gathered at this branch point, the symbol information is added to the end point on the symbol side and the branch information is added to the branch point side. If not, integrated information is added to the end points on the branch point side, and combined information is also added to all the end points gathered at the branch point. Repeat this process for all symbols,
When finished, the center line with the label 1 is erased.
(F) From the line segments output from the end points to which the symbol information is added, only the line segment to which the integrated information is added to the other end point is extracted, the average coordinates are taken from the end point group having the integrated information, and the end points Pull the flock to that point. The overlapping line obtained at this time adds branch information to the new end point. (G) If there is a point shared by two endpoints, connect two line segments having this endpoint.

Example of Invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a block diagram of an apparatus when the drawing processing method of the present invention is executed on an actual computer. CPU11, I / O device 1
5, it comprises a drawing input device 12, a recording device 13, a display device 14 and a storage device, and this storage device is divided into a plurality of memory areas 16, 17, 18 and the like. In the drawing input device 12, the image data obtained by reading the drawing,
It is stored in the memory 16 via the I / O device 15. And memory 1
The result of recognizing the contour line of the image of 6 and converting it into coordinate sequence data is stored in the memory 17. In addition, thinning is performed on the memory 16, and the result of converting the resulting thinning pattern into coordinate string data with the center line
Store in 18. The symbol connection data obtained by using the contents of the memories 17 and 18 is re-registered in the memory 18, or newly registered in the memory and output to a recording medium via the recording device 13, or a display device. Displayed on 14. CP
In U11, control of the drawing input device 12 and recording device 13, control of memory input / output, thinning, contour line recognition, center line recognition, and the above-mentioned proposed drawing process are executed. As described above, in the present embodiment, the contour line is recognized for the image in the memory 16, and the coordinate sequence data is stored in the memory 17, and
The image in the memory 16 is thinned to extract the center line, and its coordinate sequence data is stored in the memory 18.
One piece of data is position information and connection information. The outline can be recognized by scanning the outside and inside contours, and the thinning can be performed by thinning the pixels forming the figure from the outside and inside, as is well known in the image processing field. It is done by removing one row at a time. The center line is extracted by this thinning. This center line is approximated to a straight line and registered in the memory as the coordinates of the break point of the center line.

FIG. 1 is a processing flowchart showing an embodiment in the case of recognizing a symbol by using the contour line of the figure extracted in FIG. FIG. 1 shows a flow of recognizing symbols from a figure and obtaining connection information between the symbols. First, the drawing reading device is used to recognize the contour line of the figure written in the drawing, and the recognition result is linearly approximated and converted into a coordinate sequence of break points (step S101). The contour tracing result is always a closed figure. Then, a thinning process is performed (S104),
The thinning pattern thus obtained is recognized, linearly approximated, and converted into a coordinate sequence of the break point and the end point as the center line (S105).

Next, the outline is used to recognize the symbol. As described above, the contour line of the figure includes the outer contour line and the inner contour line, and the symbol always exists in the inner contour line. As an example of a method of recognizing a symbol, a method for identifying an outer peripheral contour line and an inner peripheral contour line for a graphic contour line pattern (S102), directly applying a circumscribed quadrangle to the inner peripheral contour line, and a figure represented by the outer peripheral contour line There is a method of reducing and obtaining the intersection of the reduced line segments. After recognizing the symbol, the center coordinates of the symbol are obtained (S103). Regarding the center line, a branch point is searched for, and the center line passing through this point is cut (S106). Then, of the center lines whose two endpoints do not have branch information, the line segment having the specified length or less is deleted (S107). As a result, the unnecessary thinning pattern (center line generated as noise) is erased. When a symbol is recognized, a centerline that includes the symbol center is tracked and the selected number of patterns is added as a label to this pattern. When the labeling is completed, the tracing is executed again and the connection line between symbols is created using the center line (S1
08). When tracking, erase the selected centerline. After creating the connection diagram, from the line segment coming out from the center of the symbol,
The end point group having the designated information at the other end point is put together into one end point (reorganization of branch points: S109). This removes the redundancy of the connection information in the wiring diagram. Finally, if there is a point shared by the two end points, two line segments having this end point are connected (S110). In this way, the connection information between the symbols can be obtained (S111). It is also possible to rearrange the figure by using the center line.

FIG. 3 is a diagram showing a graphic as an example of an object of the algorithm in the present invention. The case where the drawing processing method of the present invention is applied to a silhouette figure as shown in FIG. 3 will be described in order.

 FIG. 5 is a diagram illustrating a method of branch processing.

The center line branching process is shown in FIGS.
There are three cases as shown in (c). In (a), the line segment 42 that passes through the specified range 47 from the end point P of the line segment 41 and is at the closest distance is obtained, and the point A closest to P on the line segment is obtained. Then, the point P is drawn into the point A, and the line segment
Cut 42 at point A. In (b), the line segment 44 that passes through the designated range 48 from the break point P of the line segment 43 and is at the closest distance is obtained, and the point A closest to P on the line segment is obtained. Then, the point P is drawn into the point A, and the line segment 43 is drawn at the point P.
The line segment 44 is cut at each point A. In (c), the intersection P of the line segment is obtained, and the line segment 45 and the line segment 46 are cut at the point P, respectively. In all cases (a), (b), and (c), if there is another end point having branch information within the designated range centered on the point A, the point A is drawn into that point. Branch information is added to the line segment obtained by cutting and the end point of the drawn line segment. After this, among the center lines that do not have branch information at both end points, the line segments with a specified length or less are deleted.

After the branching process, the symbol is recognized. When the inner peripheral contour represents a symbol, it is necessary to identify the outer peripheral contour and the inner peripheral contour. This identification is performed using an algorithm as shown in FIG.

FIG. 6 is a diagram showing a method of selecting a tracking reference line. In FIG. 6, Y is calculated from the vector data of all contour lines.
Find the maximum value of the coordinates. Then, a perpendicular line is drawn from one of the polygonal lines of the vector data 55 or one of the end points to the boundary line of the maximum value of the data, and a line segment intersecting this line is obtained. Here, the line segments 51, 52, 53, 54 are obtained. These are the data that satisfy Xmin ≤ ≤ Xmas (1), where Xmin and Xmax are set from the smaller end point X coordinate values of the line segments that make up the vector data, and the X coordinate of the perpendicular line is x. Desired. Then, the extracted line segments are labeled in order from the line having the largest Y coordinate value at the intersection of these line segments and the perpendicular. For this label, for example, two types of 0, 1 are prepared and added in the order of 0, 1, 0, 1, .... The line assigned the label of 0 indicates the outer contour line. The line segment assigned the label of 1 indicates the inner peripheral contour line and means that there is a symbol. However,
In labeling, if the same line segment intersects twice like line segments 51, 53, and 54, labeling is not performed a second time.

Various other algorithms can be considered as the method of identifying the contour line. If the outer contour line and the inner contour line are identified using a program based on another algorithm and data is re-registered in the clockwise and counterclockwise directions respectively (this re-registration is for performing graphic operations such as reduction and enlargement). The determination of clockwise rotation and counterclockwise rotation is performed as follows. First, a circumscribed quadrangle is set for one contour line, and the minimum and maximum coordinate values are obtained. The minimum and maximum values of X coordinate and the minimum and maximum values of Y coordinate are Xmin and X respectively.
Let max, Ymin, Ymax. If the appearance of the break point or the end point is any of Xmax → Ymin Ymin → Xmin Xmin → Ymax Ymax → Xmax, it is clockwise. If any of Ymin → Xmax Xmin → Ymin Ymax → Xmin Xmax → Ymax, it is counterclockwise. When the inner peripheral contour line is obtained, the size of the circumscribing quadrangle is checked and those within the specified range are regarded as symbols. Then, the center coordinates are calculated from the circumscribed quadrangle using the following equation.

Xc = (Xmax-Xmin) / 2 ... (2) Yc = (Ymax-Ymin) / 2 ... (3) Once the center coordinates are obtained, set a line segment in the vertical direction from the center and intersect this line segment first. Find the center line to After obtaining the intersecting center lines, the center lines around the inner peripheral contour line are traced from this, and a connection diagram of symbols using this pattern is obtained.

7 (a), (b) and (c) are flowcharts showing a tracking algorithm of the center line around the inner peripheral contour line according to the present invention.

The first tracking reference line is selected as follows (S601, S
605). Now assume that you have adopted clockwise centerline tracking. This corresponds to starting tracing from the end point having the larger value of the X coordinates of the end points of the line segment that first intersects with the vertical line segment set as the center coordinate of the symbol. Tracking from the end point with the smaller X-coordinate value results in counterclockwise tracking. If the radiation intersects the centerline at a break point or a branch point, the X coordinate of the other end point of the line segments sharing this point is larger than the X coordinate value of the intersection point, and the Y coordinate Select the line segment with the smallest value and use it as the tracking reference line. When the tracking reference line is obtained, a line segment that can be connected to the line is searched (S602, 606). This is to extract a portion having the same coordinates as the end point of the reference line. Next, a correct connection line is selected from among several connection candidate lines.

FIG. 8 is a diagram illustrating a method of selecting a connection line. To select the correct connecting line, the process shown in FIG. 8 is performed. Now, assuming that a line segment 71 is obtained as the tracking reference line,
Line segments 72, 73, and 74 are obtained as connection candidate line segments. Then, with respect to each line segment, the line segment 71 is used as a reference line, and the angle formed by each line segment is measured in the range of −180 degrees to +180 degrees. When tracing a line segment clockwise, select the line segment that forms the smallest angle with the reference line, and when tracing the line segment counterclockwise, select the line segment that forms the largest angle with the reference line. . Therefore, in the case of clockwise tracking, the line segment 72 is selected, and in the case of counterclockwise tracking, the line segment 74 is selected.

In this algorithm, first, a label indicating the number of times of tracking is added to the line segment group forming the center line selected by tracking (S603). Also, labels of 0 are added to all center lines in advance. This labeling will be described next.

9 (a), (b) and (c) are explanatory views of the processing method of the present invention. The broken line in FIG. 9A is the outline of the figure. Points 809,810 are branch points, and patterns 801,802,8
03,804,805 are the center lines. Of these centerlines,
Centerlines 802, 803 are selected as the centerlines surrounding symbol 806. Centerlines 801, 802 are selected as the centerlines surrounding symbol 807. Centerline 805 is selected as the centerline surrounding symbol 808. The centerline 804 is not selected because it does not surround the symbol. Therefore, the center line 804 has a label of 0 and the center line 8
A label of 1 is added to 01, 803 and 805, and a label of 2 is added to the center line 802. This labeling is done for all closed figures by the centerline.

Returning to FIG. 7 (a), tracking is performed for all symbols (S604).

Then trace again. Set the tracking reference line (S6
05) After selecting the connecting line (S606), the line segment labeled 0 is generated from the branch point, which is a contact point, to the center of the symbol for the two line segments (S607). This line segment is of the same type as the center line. If there are only 0 or 1 labels added to the line segments gathered at this branch point (S608), the symbol information is added to the end point on the symbol side, and the branch information is added to the end point on the branch point side. (S609). Otherwise, integrated information is added to the end points on the branch point side (S610), and integrated information is added to all other branch end points (S611). For a selected line, if two or more labels are added to it (S612), a line segment with a label of 0 is generated between the midpoint of the line and the symbol center (S613), and the end point on the symbol side. The symbol information is added to and the integrated information is added to the end point on the middle point side (S614).
This line segment is also of the same type as the center line. The above processing is also performed for all closed figures by the center line, and is repeated for all symbols (S615). Finally, the center line to which one or more labels are added is deleted (S616).

Returning to FIG. 9 again, as a result of executing the center line reconstruction processing as described above with respect to FIG. 9 (a), FIG. 9 (b)
It becomes as shown in. The branch information is respectively collected at the three end points gathered at the symbol centers 811 and 812 and at the one end gathered at the symbol centers 816, that is, at the two end points gathered at the branch points 813 and 814 and the three end points gathered at the branch point 815. , The integrated information respectively gathers at the branch point 817, the branch information at the two end points,
Each is added.

Next, with respect to the line segment from one symbol, an end point group in which the other end point information has integrated information is extracted and drawn into one point. At this time, the end point having the same coordinate value is also 1
Draw to the point and erase the overlapping line. The coordinates of the new point are
Letting it be (Xp, Yp), using the coordinates (X ₁ , Y ₁ ), (X ₂ , Y ₂ ) ... (Xn, Yn) of the end point group with integrated information, Desired.

The pull-in end point has branch information.

When all the above processing is completed, a point shared by two end points is found, and two line segments having this end point are connected.
FIG. 9 (c) is a diagram showing the result of executing the pull-in and connection processing with respect to FIG. 9 (b). FIG. 9 (c) is a connection diagram of symbols finally obtained. Point 81
8 is the newly set end point, and the branch point 817 is deleted.

FIG. 10 is an explanatory diagram of a symbol recognition method by a reduction method showing an embodiment of the present invention. As shown in FIG. 10, when the symbol is represented only by the outer peripheral contour line, first, the outer peripheral contour line 90
The symbol can be recognized by moving the vector data of the figure composed of 1,902,903 to a specific memory area and reducing the figure of this data. The position of the figure (broken line) obtained by reduction is the amount of movement Δ in the axial direction of the following equation.
Calculate using X, ΔY. Now, the coordinates before reduction are P ₁ (X,
Y), the reduced coordinates are P '(X', Y '), and three consecutive points are P ₀ , P ₁ , P ₂ . X '= X + ΔX ... (8) Y' = Y + ΔY ... (9) (where (A, B) is the component of the vector P ₀ P ₁ , (C, D) is the component of the vector P ₁ P ₂ , and TR is specified. (Reduction width) is established. The reduction point is obtained by using a total of 3 points including a processing point and two points before and after. If the reduction is continued based on this equation, as shown in FIG. 10, line segment 901 becomes line segment 904, line segment 902 becomes line segment 905, line segment 903 becomes line segment 906,
Each is exchanged and the line segments intersect to form several closed areas. A group of reduced line segments forming the closed figure and a circumscribed quadrangle of the closed region formed by the group are obtained, and the center coordinates are calculated by the equations (2) and (3). In this way, when the center coordinates of the symbol are obtained, the circumscribed quadrangle is used as the window, and the center line intersecting the window is obtained. In FIG. 10, the center lines 909 and 910 correspond to this. Then, find the point on the center line closest to the center of the symbol, cut the center line at that point, and draw the cutting point to the center of the symbol,
That is, the coordinates of the symbol center are entered as the coordinates of the cutting point.
As a result, the center lines 909 and 910 are extended to the symbol centers, the end points 907 and 908 are replaced with the symbol centers, and the symbol information is added. Therefore, the symbol information is added to the end points 907 and 908.

If the symbol is shown in a different color than the contour or centerline, this information is used to recognize the symbol and cut the centerline using the method described above.

The connection information of the symbol can be obtained from the center line thus obtained. Further, it is also possible to rearrange the figure by using the center line.

FIG. 11 is a symbol wiring diagram obtained from FIGS. 3 and 4. FIG. 11 shows the result of applying the algorithm of the present invention to the printed circuit board diagram of FIG. 3 and displaying connection information between symbols by connecting center lines.

The addition of the integrated information, the symbol information, and the branch information to the end points can be realized by providing an area for registering the start point and end point information in the memory that stores the polygonal line data. In this way, for example, integrated information 1, symbol information 2, branch information 4
Then, these can be distinguished from each other by bit correspondence.

As described above, in this embodiment, by applying to the recognition of the silhouette figure, not only the recognition of the symbols but also the connection relation between the symbols can be obtained from the drawing. Then, these data can be used as input data to a design automation system that creates and corrects a design drawing, rearranges graphics, or the like, or as data to be delivered to a product manufacturing line.

〔The invention's effect〕

As described above, according to the present invention, since it is possible to accurately obtain the arrangement information of a figure together with a symbolic wiring diagram even from a filled figure, it can be effectively used as input data of a design automation system.

[Brief description of drawings]

FIG. 1 is an overall flowchart of a drawing processing method showing an embodiment of the present invention, FIG. 2 is a block diagram of a computer system to which the drawing processing method of the present invention is applied, and FIG. 3 is a diagram showing an object graphic of an algorithm, FIG. 4 is a diagram showing the results of recognition of contour lines and center lines, FIG. 5 is a diagram showing a branching processing method showing an embodiment of the present invention, and FIG. 6 is a method of selecting tracking reference lines according to the present invention. FIG. 7, FIG. 7 is a flow chart of a tracking operation showing an embodiment of the present invention, FIG. 8 is a view showing a connecting line selecting method in the present invention, and FIG. 9 is a drawing processing method showing an embodiment of the present invention. FIG. 10 is an explanatory view of the intermediate operation of FIG. 10, FIG. 10 is an explanatory view of a symbol recognition method by a reduction system showing another embodiment of the present invention, and FIG. 11 is a symbol connection diagram obtained from FIG. 11: CPU, 12: drawing input device, 13: recording device, 14: display device, 15: I / O device, 16, 7, 18: memory area, 41 to 46, 71 to 74,
801 to 805,909,910: Center line, 47,48: Window, 51 to 55,
901 to 903: Contour line, 904 to 906: Reduced contour line, 56: Maximum boundary of Y coordinate value, 75,809 to 810,817,818: Branch end point, 806 to 808,8
11,812,907,908: Symbol center point, 813 to 815: End points having integrated information.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-11884 (JP, A) Transactions of the Institute of Electronics, Information and Communication Engineers Vol. J68-D No. 4 1985.4 “Sequential thinning of binary images using distance transformation results” Satoshi Suzuki. Keiichi Abe

Claims (4)

(57) [Claims] 1. A drawing processing method for inputting a drawing in which a graphic including a fill is described into a computer to obtain a symbol described in the drawing, connection information of the symbol and layout information of the graphic. To extract the graphic information including at least the contour line, to remove the pixels from both sides of the contour line of the extracted graphic one by one to obtain the center line by thinning the graphic, and to draw the center line as a straight line. A process of approximating and converting the center line into coordinate sequence data by expressing the end points and break points thereof in the coordinate sequence data; a process of recognizing a symbol of a shape designated in advance using the above graphic information; A drawing processing method comprising the step of: integrating the symbols to obtain a connection diagram of the symbols passing through the center of the recognized symbol. 2. The graphic information is a contour line of a filled figure, and in the process of recognizing a symbol having a shape designated in advance, the contour line is approximated by a straight line and its break point is represented by coordinate sequence data. The process of converting the contour line into coordinate sequence data by the method, and reducing the outer contour line of the figure to extract the intersection and recognize the symbol by the extracted intersection, or the size of the inner contour line of the figure The method for processing a drawing according to claim 1, further comprising the step of recognizing a symbol according to. 3. The graphic information includes color information on a drawing,
The process of recognizing the symbol of the previously designated shape includes the process of recognizing the color information, and the process of integrating the center lines to obtain a connection diagram passing through the center of the symbol is on the center line closest to the center of the symbol. 2. The drawing according to claim 1, which comprises a step of finding the point and a step of cutting the center line at the found point and making the coordinates of the cutting point the same as the coordinates of the symbol center. Processing method. 4. A drawing processing method for inputting a drawing in which a graphic including a filling is described into a computer to obtain a symbol described in the drawing, connection information of the symbol and layout information of the graphic. To extract the graphic information including at least the contour line, to remove the pixels from both sides of the contour line of the extracted graphic one by one to obtain the center line by thinning the graphic, and to draw the center line as a straight line. The process of approximating and converting the center line into coordinate sequence data by expressing the end points and break points with the coordinate sequence data; the process of recognizing a symbol of a shape designated in advance using the graphic information; and the center line At the bifurcation point, a process of tracing the center line around the recognized symbol to obtain a center line group surrounding the symbol, and a center line surrounding other symbols among the center lines surrounding the symbol. In sharing lines There is a process of finding a line, a process of generating a line segment from the midpoint of a branch point and a shared center line to the center of a symbol, and a process of replacing the generated line segment group into one line segment. A drawing processing method characterized by relating.