JPS6068482A - Detecting circuit of intersecting point - Google Patents

Abstract

PURPOSE:To eliminate the effect of variance of the line width of an input linear pattern and to detect accurately an intersecting point, by deciding the threshold value of a certain line width from the line width of the input linear pattern, extracting an area near the intersecting point according to said threshold value and extracting the intermediate point as an intersecting point. CONSTITUTION:The size of an area to be processed is stored to a register 1, and the output of the register 1 is delivered to a horizontal line width deciding circuit 3. While the size stored to the register 2 is delivered to a vertical line width deciding circuit 4. Then data are supplied to both circuits 3 and 4, and the circuits 3 and 4 scan each side by the outputs of registers 1 and 2 to detect the threshold values of both horizontal and vertical line widths. These threshold values are applied to horizontal and vertical segment deleting circuits 7 and 8 via registers 5 and 6 respectively. Then the horizontal and vertical segments are deleted by the outputs of the circuits 3 and 4. The outputs of the circuit 7 and 8 undergo the logical processing through a horizontal/vertical data AND circuit 9. Then an intersecting point is detected accurately by an intersecting position detecting circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an intersection detection circuit that determines intersections of line figures from data of line figures divided into predetermined rectangular areas.

(b) Background of the technology When recognizing figures such as city maps, recognizing and determining the intersection position between two figures is one of the important techniques for recognizing figures. Conventionally, various methods have been used to recognize and determine the intersection, but each has its own drawbacks, and there is a need for the development of a more reliable method for detecting the intersection.

(c) Prior Art and Problems A conventional method for detecting intersections of line graphic data will be explained with reference to the drawings.

FIG. 1 is a diagram illustrating the processing of the conventional method for extracting intersection points of line figure data, in which (A) shows an input line figure and (B) shows a line figure from which intersection points have been extracted.

In the figure, a and b indicate extracted intersection points.

Conventionally, when extracting intersection points from line figure data, the first
The input line figure shown in figure (A) is once thinned (a process of thinning a line figure with a certain thickness to a line with a line width of 1) from the top, bottom, left and right without degenerating the end points and without losing connectivity. Intersections were then extracted by mask scanning (scanning using a character pattern to control the retention or erasure of portions of a character pattern).

However, in the above method, extra whiskers occur during line thinning processing, and the line width of each line figure is not necessarily constant. As shown in Figure (B), there is a problem in that a plurality of intersections (two locations a and b in this example) are extracted, and that accurate intersection extraction is not possible.

(d) Object of the Invention The object of the present invention is to provide a novel intersection detection circuit that eliminates the above-mentioned drawbacks, and in particular, determines the darkness value of the line width consisting of the line width of an input line figure, and By extracting the vicinity of the intersection based on the darkness value and extracting the intermediate point as the intersection, we have created an intersection detection circuit that can extract stable and accurate intersections even when the line width of the input line figure varies. It's about making it happen.

(e) Structure of the Invention The present invention provides an apparatus for recognizing the input figure by dividing an input line figure into certain rectangular areas and scanning the line figures within the two divided rectangular areas in the horizontal and vertical directions. a circuit that determines a darkness value of the line width of the line figure within the rectangular area based on data obtained by scanning each side of the line figure within the area in the horizontal and vertical directions; a circuit that removes line segments based on the darkness value; By providing a circuit for determining an intersection point in a portion other than the above, this can be achieved by an intersection detection circuit characterized in that stable and accurate intersection extraction can be performed even with variations in the line width of the input line figure.

<f’) Examples of the invention The present invention will be explained below with reference to the drawings.

FIG. 2 shows an embodiment of the intersection detection circuit according to the present invention.

FIG. 3 shows a flowchart of the processing according to FIG. 2, respectively.

In the figure, 1.2, 5.6.11 are register circuits, 3
4 is a horizontal line width determining circuit; 4 is a vertical line width determining circuit;
7 is a horizontal line segment removal circuit, 8 is a vertical line segment removal circuit, 9 is a horizontal/vertical data AND circuit, and 10 is an intersection position detection circuit.

In addition, ■ to ■ indicate the processing status of each part of the intersection detection circuit of this embodiment, ■ is one rectangular area data input to the intersection detection circuit, and ■ is the darkness value determined by scanning in the horizontal direction (
The data after passing through a circuit that removes line segments based on WLW2), ■ is the threshold value determined by scanning in the vertical direction (
data after passing through a circuit that removes line segments based on W3), ■ is the output data of the horizontal/vertical data AND circuit 9,
■ is the data stored in the register circuit 11, C is the intersection point where C is inserted, d is the starting point of the rectangular area, and WD is 1 of the rectangular area.
The length of the side, W2.43 is the line width darkness value of each side of the rectangular area, Y (y) is the vertical axis of the rectangular area, and X (x) is the horizontal axis of the rectangular area.

In this embodiment, a register circuit 1 stores data of a rectangular area to be processed (data regarding dimensions of the rectangular area) sent from a previous circuit (not shown) and outputs it to a horizontal line width determining circuit 3. A vertical line width determining circuit 4 stores the data of the rectangular area to be processed, also sent from the previous circuit.
A register circuit that outputs to 2. Each side in the horizontal direction is scanned from the data output from the register circuit 1, and the darkness value of the line width (W
1, W2); horizontal line width determination circuit; 3. Vertical line width determining circuit 4 which scans each side in the vertical direction from the data output from the register circuit 2 and determines the darkness value (day) of the line width. The darkness value (Kl,
5. Register circuit for storing W2). A register circuit 6 for storing the darkness value (3) determined by the vertical line width determination circuit 4. Horizontal line segment removal circuit that removes horizontal line segments based on darkness value (old, eye) 7. Vertical line segment removal circuit that removes vertical line segments using a threshold value (eye) 8. 9. A horizontal/vertical data AND circuit 9 which performs the logical product of the output of the horizontal line segment removal circuit 7 and the output of the vertical line segment removal circuit 8 and extracts the vicinity of the intersection point. An intersection position detection circuit 10 that extracts the midpoint of the data obtained from the horizontal/vertical data AND circuit 9 and generates the address of the obtained intersection. Intersection position detection circuit 1
It is composed of a register circuit 11 that stores data starting from 0.

The operation of this embodiment will be explained based on FIG.

Output from the previous circuit (not shown) and register circuit 1,
Each side in the horizontal and vertical directions is scanned with respect to the data stored in 2, and the line width determination circuit 3 and the vertical line width determination surface determine the line width (darkness value) in each direction. FI
It is executed in II4 and temporarily stored in the register circuits 5 and 6.

The horizontal line segment removal circuit 7 performs scanning based on the threshold value (cho, trust) stored in the register circuit 5.

Line widths smaller than the darkness value (Wl, W2) are removed.

Predetermined data Wx■ regarding the horizontal direction is obtained. Note that the predetermined data WX regarding the horizontal direction obtained in this case is Wl>
When W2, Wx=W1+α', when Ml<W2(7), Wx
= Interval + α.

On the other hand, the vertical line segment removal circuit 8 performs scanning based on the darkness value (eye) stored in the register circuit 6.

Line widths that are 6 smaller than the darkness value (day) are removed to obtain predetermined data in the vertical direction wy■=W3+α.

The horizontal/vertical data AND circuit 9 extracts the data (blacked out portion) obtained by logically multiplying Wx■ and wy■ as the vicinity of the intersection. The intersection position detection circuit 10 detects the center point C of this data (2) when viewed horizontally and vertically. This center point C is the starting point d of the input rectangular area (
XO, YO), the coordinates of the center point C are (XO+x
1. YO+yl), and this data (2) is output to the register circuit 11 and stored.

(g) Effects of the Invention According to the present invention as described above, it is possible to provide an intersection detection circuit that can stably and accurately extract intersections even with variations in line width of input line figures.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the processing of a conventional method for detecting intersections of line figure data, FIG. 2 is an embodiment of an intersection detection circuit according to the present invention, and FIG. 3 is a flowchart of the processing according to FIG. 2. . In the figure, 1.2, 5.6.11 are register circuits, 3
4 is a horizontal line width determining circuit; 4 is a vertical line width determining circuit;
7 is a horizontal line segment removal circuit, 8 is a vertical line segment removal circuit, 9 is a horizontal/vertical data AND circuit, and 10 is an intersection position detection circuit.

Claims (1)

[Claims] In an apparatus for recognizing an input figure by dividing an input figure into certain rectangular areas and scanning the divided rectangular area line figure horizontally and vertically, each side of the rectangular area inner line figure is scanned horizontally and vertically. A circuit that determines the darkness value of the line width of the line figure within the rectangular area based on the data obtained by scanning the area, a circuit that removes the line segment based on the darkness value, and an intersection point determined at 1. An intersection detection circuit characterized by comprising a circuit for detecting a point of intersection.