JPS61131172A - Polygonal line approximate system of line diagram - Google Patents

Abstract

PURPOSE:To execute the polygonal line approximation for which the fidelity is high and a processing speed is fast by executing the thinning processing and the polygonal line approximation concerning the area for which the thinning processing is necessary, and incorporating the thinning processed area and the polygonal line approximated area. CONSTITUTION:A picture data inputted by a picture input device 1 are accumulated in a picture memory 2, and by an address signal of an address control part 4 controlled by a control part 3, a prescribed area is read. At such a case, in case of a complicated line diagram, the polygonal line approximation is executed by the second polygonal line approximate circuit 7 after the thinning is executed at a thinning circuit 6. At such a case, the intersection of the border between a polygonal line approximated part and the thinning part is stored, and a black picture element sandwiched with a line segment pair used for the broken line approximation is deleted and the thinning processing is executed. Next, inflection point data of the thinning processed diagram by the circuit 7 are obtained, and the border part is incorporated at an incorporating circuit 8 based upon the data concerning the intersection stored beforehand. Thus, the polygonal line approximation of the line diagram can be executed in which the fidelity is high and the processing speed is fast.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a graphic processing method in an image information processing system, and particularly relates to a method of approximating a line figure to a broken line without thinning it, and a method of approximating a broken line by thinning the line figure. This paper relates to a broken line approximation method for line figures that uses a combination of .

[Conventional technology]

Conventionally, as methods for approximating line figures for line figures, there are two methods: first thinning the line figure and then performing the line approximation, and two methods that extract and integrate bending points in the outline and create a line approximate figure without performing line thinning processing. There is a way to obtain it.

[Problem that the invention seeks to solve]

The thinning process involves repeating scanning to delete removable points so as not to degenerate the end points at the internal boundary. This process takes a long time and also creates unnecessary line segments in the polygonal line approximation figure due to the influence of noise. or the figure may be cut off. On the other hand, the method of obtaining a polygonal line approximation figure by extracting and integrating bending points in the contour line has the disadvantage that polygonal line approximation processing for complex figures cannot be performed satisfactorily.

[Means for solving problems]

The present invention provides a broken line approximation method for line figures that solves the above-mentioned problems. When a line figure area in which the broken line approximation is difficult is detected, a thinning process is applied to the line figure area to obtain the line figure part that is approximated by the broken line, and a line figure part that is approximated by the broken line and a line figure obtained without the line thinning process is obtained. The line figure parts are integrated to obtain a broken line approximate line figure of the free drawn line figure.

[Effect]

According to the method of the present invention, as a result of performing a broken line approximation of a line figure within a predetermined region that has been cut out, thinning processing and broken line approximation are performed for the region that requires thinning processing, and the region that has been subjected to the thinning processing and the thinning A polygonal line approximation of a line figure is performed by integrating the polygonal line approximation areas without the polygonal line approximation.

Therefore, it is possible to perform polygonal line approximation of line figures with high fidelity and high processing speed.

〔Example〕

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, 1 is an image input device, such as a facsimile machine, which reads freely drawn line figures. Image data input by this image input device 1 is stored in an image memory 2. After that, the address control section 4 controlled by the control section 3
A predetermined area is read out by the address signal. FIG. 2 shows a line figure, such as a city map, cut out in this way. As shown in FIG. 3, this line figure includes contact points T, -T6 and bending points P, -P4 at the boundary between the cutout part and the line figure, so each of these points is By determining the median line C from the vector in , a polygonal line-like figure as shown in FIG. 4 can be obtained. By the way, in the case of a complicated line figure as shown in FIG. 5, it is not possible to completely approximate the broken line in a vector manner, so after thinning the line in the thinning circuit 6 shown in FIG. Approximate. When selecting the thinning circuit 6, for example, it is determined whether or not there is a paired line P278 corresponding to the line segment shown at the bending point P and the contact point Ts in FIG. investigate.

At this time, 01 in FIG. The intersection of the boundary between the portion approximated by the broken line and the portion to be thinned, indicated by D2, is memorized. Then, erase the black pixels sandwiched by the pair of line segments used in the approximation, and Dl
, D2 is subjected to line thinning processing by a line thinning circuit 6, and bending point data of the figure subjected to line thinning processing is obtained by a second broken line approximation circuit 7. Furthermore, the boundary portions are integrated in an integrating circuit 8 based on data regarding the intersections D1 and D2 stored in advance, and a broken line approximate figure 9 as shown in FIG. 7 is obtained.

〔Effect of the invention〕

According to the present invention, line thinning processing is performed only in sections where line thinning is required, so that an approximate figure that is faithful to the original line figure can be obtained with less influence of noise, and a broken line of a line figure that can be processed quickly. An approximation scheme is provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing an example of a cut-out line figure, FIG. 3 is a diagram showing an example of a line figure shown with contact points and bending points, and FIG. The figure shows an example of a line figure approximated by a broken line, Figure 5 shows another example of a line figure, Figure 6 shows a part to be thinned and a part approximated by a broken line. FIG. 7 is a diagram showing an integrated broken line approximate figure. ■... Image input device, 5... First broken line approximation circuit, 6
...Thin line circuit, 7...Second broken line approximation circuit, 8...
integrated circuit. Agent Patent Attorney Calibration Hiroshibu (, KO',, 1
．． ．． ．． ．． ．． ．． i, :) Figure 1 Figure 2 Figure 3 Figure 3 T4 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) Performs broken line approximation on the input free-drawing line figure without performing line thinning processing, and when a line figure area for which broken line approximation is difficult is detected, performs line thinning processing on that line figure area. The method is characterized in that the broken line approximate line figure part is obtained, and the broken line approximate line figure part and the broken line approximate line figure part obtained without line thinning processing are integrated to obtain the broken line approximate line figure of the free drawing line figure. Broken line approximation method for line figures. (2) The detection is performed by extracting line segments that are paired with the line segments between bending points extracted from the outline of the line figure, and the integration is performed by thinning processing for sections where the paired line segments are not extracted. 2. The broken line approximation method for a line figure according to claim 1, wherein the method is performed based on data of end points in the section.