JPS5953969A - Linear figure vector-converting system - Google Patents

Abstract

PURPOSE:To make a linear figure approximate easily to a vector, by extracting a tracking start point, setting a prescribed frame as to this point, tracking the contour line of a linear pattern in the frame, connecting the middle point of an intersection point to the frame side and the center of the frame as a result of tracking to set the vector. CONSTITUTION:A picture element data read out of a picture file 11 is stored temporarily in a buffer 12 and a register 13 in a tracking start point detecting part 25 of the upper stage through a bus, and tracking start points P, Q are detected by a deciding device 14. Subsequently, a buffer 15 in the contour line tracking part 26 is turned on, all data in the frame around the center R of the points P, Q are stored directly in a two-dimensional buffer 16 from the file 11, and tracking is executed clockwise or counter-clockwise from the points P, Q. Subsequently, the address of a contour point is sent to a picture element deciding part 19, tracking is executed to the frame side, and the middle point between the intersection points is set and the branch check is executed. Also, a vector data for connecting the points P, Q and the middle point between the intersection points is obtained by a vector-converting part 27.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for vectorizing a figure consisting only of line figures on a drawing as a binary painter in order to compress a small amount of data.

(2) Prior art and problems Conventionally, information on hand-drawn drawings (circuit diagrams, mechanical designs, flow charts, etc.) drawn by designers during CAD (design method for total x machine box) related work and computer internal representations The part that converts to When reading, transmitting, and recognizing not only CADK but also general drawings, the biggest problem is compression of the figures.

Among the various drawings mentioned above, vectorization is used as a data compression method for circuit diagrams, printed board pattern diagrams, mechanical design drawings, etc. that are composed only of line figures.

A method of compressing information by approximating a figure consisting of a straight line and two curves with a finite number of directed line segments (vectors) is effective in giving meaning to these figures, that is, in pattern recognition.

By approximating the image data in FIG. 1 (α) by a directed line segment (vector) as shown in FIG. 1 (<b), the amount of data can be significantly reduced.

(3) Purpose of the Invention The purpose of the present invention is to provide a line graphic vectorization method that uses a small amount of data and is easy to process when a figure consisting only of line figures on a drawing is read as a binary image and vectorized for data compression. It is to be.

(4) Structure of the Invention In order to achieve the above-mentioned object, the line figure vectorization method of the present invention reads a figure consisting only of line figures on a drawing as binary image data and vectorizes it for data compression. means to detect two points corresponding to both sides of the p-line on the scanning line as the tracking start point, find the first midpoint between the two points, set a predetermined frame around this point, and start tracking. a contour tracing means that traces the contour line in opposite directions from point to point to find the point of intersection with the frame side, and a second midpoint between the two intersections with the frame side, and the first midpoint. and vectorization means for setting a vector connecting the second midpoint, and a similar frame is set based on the second midpoint in the following, and tracing by the contour tracing means and vector setting by the vectorization means are performed. If this is repeated and the line figure is sequentially converted into a vector, it becomes a vil-feature.

(5) Examples of the invention FIGS. 2(a) to 2(c) are schematic illustrations of the present invention.

Figure (α) is a flowchart of the main functions, which are roughly divided into 9.6 stages and repeated, and Figure (6) is a graphical representation of this.

In the first step, the line figure 1 on the drawing is scanned by p scanning lines to extract the tracing start point (■). Next, in the second stage, we move on to contour tracing. First, we set a predetermined frame 2 in relation to the tracing start point, and perform contour tracing of the line figure within this frame (@)
. In the sixth step, vectorization is performed, and a vector is set by connecting the center of the frame and the midpoint of the two intersections with the sides of frame 2 as a result of contour tracing (0). Next (set a frame centered on the midpoint of the two intersections with the frame sides, trace the outline of the line figure within that frame, and set the vector in the same way. , and the line figure 1 in (6) of the same figure can be approximated as a whole by the vector 6 of (0) in the same figure.

FIG. 3, FIG. 4, and FIG. 5 (a) + <b) are detailed explanatory diagrams of the above-mentioned steps of extracting the tracing start point and tracing the contour line.

FIG. 6t shows the procedure for extracting the tracking start point.

Now, regarding the pixels on the drawing, white indicates 60" and black indicates 11", and line figure 1 is expressed as a series of black "1"s.

First, a point P where the color changes from white to black and a point Q where the color changes from black to white are detected using a scanning line. Several such pairs of P and Q can be found, but among them, the one whose distance of PQ is less than a certain value is adopted.

FIG. 4 shows the procedure for contour tracing.

After the tracing start points P and Q are found, contour tracing is performed from these two points. The center R of points P and Q is determined, and a frame 2 of a predetermined size with R as the center is set. The contour is traced counterclockwise from point P and clockwise from point Q, and when it reaches the intersections Le and 'Re with the frame sides of frame 2, the tracing is stopped there. Let S be the midpoint between the intersections Le and Re. Also, track from point P clockwise and counterclockwise from point Q to the intersection point L with the frame side.
'e, Rh and their midpoint S' are also recorded. And L
Connect midpoints S and R of e, Re, and also L'e, R'
Connect the midpoint S' of e and R to create vectors.

Next, set a frame 2' adjacent to frame 2 and based on S, and
Contour tracing is performed from e and Re to create the next vector.

A line figure is approximated as a vector figure by a set of vectors created in this way.

Figure 5 (α), Cb) branches in the contour tracing procedure,
The processing procedure when there is a bend is shown.

Figure (a) shows the case of a branch line figure. That is, as a result of contour tracing from the tracing start points Ls and Rs to the line figure 1 in the frame 2, the intersections with the frame sides Le■, fl
If ■ has expanded greatly compared to the line width, scan the frame 2 to detect the black end points ■ and ■, trace the outline from the end point ■ by turning the time =, and match the end point ■. You can see that it is branched as shown in the figure.

In the case of (b) in the same figure, the result of scanning on frame 2 is (α) in the same figure.
Similarly, even if black endpoints ■, ■, and ■ are detected, if Rs and ■ are connected as a result of contour tracing from R8 or endpoint ■, then the black endpoints ■, ■ are noise. I understand something.

FIG. 6 is an explanatory diagram of the configuration of an embodiment of the present invention.

In the figure, an image file 11 stores binary image data of a figure consisting only of line figures to be vectorized.

A tracing start point detection unit 25 is provided in the upper stage, a contour tracing unit 26 is provided in the middle stage, and a vectorization unit 27 is provided in the lower stage.The result data of the contour tracing unit 26 is output to the CPU, and the data is outputted from the CPU to the vectorization unit. 27. It goes without saying that the transfer of image data to and from the image file 11 is controlled by the CPU 10. The pixel data read from the image file 11 is temporarily stored in the buffer 12 and register 13 in the upper tracking start point detection unit 25 through the bus. The determination unit 14 detects the tracking start points P and Q as shown in FIG.
All the data within the frame 2 centered on the straight line R explained in the figure is stored directly from the image file 11 into the two-dimensional buffer 16, and tracking is performed clockwise or counterclockwise from the tracking starting points P and Q. It will be done. In other words, 6x6 pixel window 2
It is set on the contour line starting from the tracing start point of the dimensional buffer 16, and the 8-neighborhood counter 20 is checked with the contour point as the center, and the address of the next contour point is stored in the register (X) 17. ('i'
) 18 and then sent to the pixel row foot section 19, and contour point tracking is performed up to the frame edge. CP the intersection data with this frame side
Then, the center setting between the intersection points and the branch check are performed.

Also, when the processing within one frame is completed, a termination signal is output from the two-dimensional buffer 16, the buffer 21 of the vectorization unit 27 is turned on, and vector-related data from the CPU is transferred to the buffer 2.
1 and stored in the register 22, new vector data connecting the midpoint between the tracing start point and the intersection of the frame sides is created. Then, the angle calculator 23 calculates the angle of the new vector and branches. It passes through the processor 24 as it is and outputs a vector.On the other hand, in the case of a branch line figure as shown in FIG. Then, a vector corresponding to the branch line figure is separately created and output.The above procedure is repeated for each frame.

(6) As described in detail, according to the present invention, a tracing start point is extracted, a predetermined frame is established in relation to this point, and the outline of a line figure within this frame is traced. As a result of tracking, a vector is set by connecting the midpoint between the intersections with the frame sides and the center of the frame.

In this way, the data necessary for setting a vector is reduced to a minimum, so it is possible to easily and quickly approximate a line figure to a vector.

Figures 2 (a,) to (C) are schematic explanatory diagrams of the present invention, Figures 3 to 5 (α), and (b) are detailed explanatory diagrams of the main parts of Figure 2, and Figure 6 is the main part of the present invention. It is a configuration explanatory diagram of an embodiment of the invention, in which 1 is a line figure, 2 is a frame, 3 is a vector, 4 is noise, 1
1 is the image file, 12.15.21 is the buffer, 16
17, 18, 22 are registers, 14 is a judge, 19 is a pixel judge, 20 is an 8-neighborhood counter, 26 is an angle calculator, 24 is a branch processor, 25 is a tracking start point production unit, 26 is a contour line A tracking section 27 indicates a vectorization section.

Patent applicant Fujitsu Ltd. Sub-agent Patent attorney 1) Yoshishige Saka Figure 1 (a) (b) (8)
Figure 2 ■ Figure 83 Figure 4 L-J b

Claims (1)

[Claims] (1) In the method of reading figures consisting only of line figures on a drawing as binary image data and converting them into vectors for small data compression, the two points corresponding to both sides of the scanning line on the drawing are the starting points for tracing. A first midpoint between the two points is found, a predetermined frame is set around this point, and the contour is traced in opposite directions from the tracing start point to the edges of the frame. 29. Contour tracing means for finding intersection points with the frame sides. vectorizing means for determining a second midpoint between the points and setting a vector connecting the first midpoint and the second midpoint; , and then repeatedly perform tracking using the contour tracing means and vector setting using the vectorization means. A line figure vectorization method that targets successive vectorization of IM figures. (2) As a result of tracing by the contour tracing means, if the two points with the frame side have expanded greatly relative to the line width, scan the frame side to detect untracked points corresponding to the width a, and 2. A method for converting line figures into vectors according to claim 1, characterized in that branch line figures are converted into vectors by performing tracking on untracked points.