JPS6151271A - Broken line approximation system of line pattern - Google Patents

Abstract

PURPOSE:To obtain an approximate line pattern loyal to an original line pattern by incorporating an inflection point which exists on a fine-line line pattern, creating a characteristic point and making a line pattern approximate to a broken line based upon the characteristic point. CONSTITUTION:A free picture making drawing is read by a picture input device 1 under a control of an address control part 8 and fetched into a picture memory 2 as a binary output signal. In part of the line pattern, ain inflection point is extracted by an inflection point extracting part 3 and simultaneously, a linked line pattern is created at a fine line part 4. The inflection point is shifted onto the fine-line pattern by an inflection point shifting part 5 and a prescribed processing is executed. A distance between obtained inflection points is calculated at an inflection point incorporating part 6, and when the value is a threshold or below, a true center of gravity is obtained by incorporating them and a broken line approximately pattern can be made.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an improvement in a broken line approximation method for line figures.

In processing line figures such as maps, there is a technique that performs a broken-line approximation of the line figure to proceed with the processing of the line figure.

Naturally, it is desirable that the broken line approximation be performed while preserving the characteristics of the original line figure as much as possible.

It is also important that the above requirements can be met by eliminating the contamination of undesirable elements during the processing.

[Conventional technology]

The conventional broken line approximation method for line figures first thins the line figure,
One inflection point or one branching point of the thinned line figure is extracted, and based on these points, an approximate figure is obtained by the broken line approximation of the line figure.

[Problem that the invention seeks to solve]

In this method, whiskers are likely to occur at the inflection point and one branch point when the line figure is thinned, and therefore, the obtained approximate figure is a faithful approximate figure that sufficiently preserves the characteristics of the original line figure. The disadvantage is that there are cases where this is not possible.

[Means for solving problems]

The present invention provides a broken line approximation method for line figures that can solve the above-mentioned problems. means for extracting, means for thinning the line figure pattern, means for moving the bending point on the thinned line figure pattern, and integrating the bending points existing on the thinned line figure pattern. and means for generating feature points based on the feature points on the line figure pattern, and the line figure is approximated by broken lines based on the feature points on the line figure pattern.

[Effect]

According to the method of the present invention, the bending points extracted from the line figure pattern are moved onto the thinned line figure pattern, the moved bending points are integrated to generate feature points, and each feature point is used as the basis. Since the broken-line approximation of the line figure is obtained by using this method, it is possible to obtain an approximate line figure that is faithful to the original line figure to which the receiver continues without losing the characteristics of the original line figure.

[Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the invention. In this figure, ■
is an F that generates a line figure signal from a freely drawn imaged object.
In an image input device such as AX, 2 is the 2 from image input device 1.
This is an image memory that stores digitized image (line figure) output signals. Reference numeral 3 denotes an inflection point extracting section which cuts out a line figure pattern in the size of the image memory 2 and extracts inflection points from the line figure pattern. Reference numeral 4 denotes a thinning section that thins the line figure pattern. Reference numeral 5 denotes a bending point moving unit that moves the bending point in the thinned line figure pattern. Reference numeral 6 denotes a bending point integrating unit that integrates bending points on the thinned line figure pattern to generate feature points. 7 is a control unit, which includes a bending point extraction unit 3;
The thinning section 4, bending point moving section 5, bending point integrating section 6, and address control section 8 are placed under the control of a control section 7, and the address control section 8 controls writing to the image memory 2 and reading from it. control.

The process of polygonal line approximation of a line figure under the above configuration will be described below.

A free drawing drawing is read by the image input device 1, its line figure data is taken into the image memory 2 under the control of the address control section 8, and a part of the line figure pattern is extracted by the bending point extraction section 3. (see Fig. 2), and the bending point is extracted therefrom (see Fig. 3). This bending point extraction technique is the “line figure bending point extraction method” disclosed in the patent application No.
Use. By performing this extraction process, a slope code having a value of 0 to 24 is assigned to each point on the contour of the line graphic pattern (see FIGS. 5 and 6).

Along with this process, the line figure pattern shown in FIG. 2 is thinned by the line thinning section 4 to generate a thin line figure pattern with a four-connected line width of 1 as shown in FIG.

Then, the bending point moving unit 5 moves the above-mentioned bending point onto the thinned line figure pattern.

This movement is caused according to the inclination code of the inflection point, as shown in FIG. The slope code is given to each point on the outline of the line figure in the above-mentioned bending point extraction process,
This is shown in FIG. In Figure 5, the white circle (
0) is a point on the contour, a double circle (◎) is a bending point, and the numbers inside these circles are inclination codes. Further, X indicates a thin line pattern. The movement of the bending point onto the diagrammatic line pattern will be explained as follows with reference to FIG. For example, since the inclination code of the inflection point is 1, it becomes point V on the line figure pattern that has been moved upward and thinned. Since the inclination code of the inflection point ■ is O, the inclination codes before and after it can be checked.

Since the bending points (3) are 4 and 10, their moving directions are upper left and lower left, respectively, but their overall moving direction is left, which is point v3. Similarly, point v2
．． v4 is also determined.

An inflection point, such as point V, moved as described above.

The distance between 74 is calculated in the bending point integration unit 6,
If the value is less than or equal to the threshold, the center of gravity obtained by integrating them is taken as the true feature point.

The result obtained by applying the above series of processes to the line figure pattern of FIG. 1 is a broken line approximate figure as shown in FIG.

By performing the above-described series of processes for each cut-out line figure pattern, it is possible to obtain a broken line approximation figure for the entire imaged and captured line figure pattern. -1 In the above embodiment, a case has been described in which the bending point extraction process for the cut out line figure pattern and the line thinning process for the same pattern are performed in series, but it is also possible to perform these processes in parallel. Needless to say, it may be configured.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to 1) eliminate the effects of whiskers, etc. that occur during thinning, 2) achieve data compression, and 2) make raw cotton that fully retains the characteristics of the original line figure. Effects such as being able to obtain a polygonal line approximation figure that is faithful to the figure can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a cut out line figure pattern, FIG. The figure shows a thin line figure pattern of the pattern in Figure 2, Figure 5 is an enlarged view of the pattern in Figure 1 to explain the movement of the bending point, and Figure 6 shows the inclination code and its movement direction. FIG. 7 is a diagram showing a broken line approximate figure of the pattern in FIG. 2 that has been processed according to the present invention. In the figure, 1 is an image input device, 2 is an image memory, and 3 is a bending point extraction 4 is a thinning section, 5 is a bending point moving section, 6 is a bending point integrating section, 7 is a control section, and 8 is an address control section. wE6 diagram inclination code Material force direction 24.1,2 ↑ 3.4,5 \6.7.8 + 9.10,11 i 12.13,14 No. 15, 16, 17 \18.19,20 → 21 .22,23 / Figure 7

Claims (2)

[Claims] (1) means for outputting a binarized line figure pattern of a line figure; means for extracting bending points of the line figure pattern;
A means for thinning the line figure pattern, a means for moving the bending point on the thinned line figure pattern, and a feature point is generated by integrating the bending points existing on the thinned line figure pattern. A broken line approximation method for a line figure, characterized in that the line figure is configured to be approximated by a broken line based on feature points on the line figure pattern. (2) The broken line approximation method for a line figure according to claim 1, wherein the bending point extracting means extracts a bending point within a region cut out from the line figure pattern.