JPH0313626B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for extracting reference points in a graphic input device.

Along with the rapid progress of information processing technology, automatic design and manufacturing (CAD, CAM) are becoming popular at a rapid pace. In this automatic design and manufacturing system, handwritten drawings are automatically read and recognized,
Processing technology for later automatic drafting, etc. is one of the technologies that occupies an important position.

The present invention relates to an improvement in a method for extracting a reference point that serves as a reference for recognition processing in a graphic input processing device that performs such processing.

[Prior Art] A graphic input processing device is used to automatically read handwritten printed board pattern diagrams, logic circuit diagrams, various wiring diagrams, etc. Here, the case of printed board pattern diagrams will be described.

Hand-drawn printed circuit board pattern diagrams are generally drawn using a grid (usually
A grid corresponding to 2.54 mm spacing is handwritten on paper printed in a color that is not detected by the scanner of the graphic input processing device.

When the figure drawn on this grid is recognized, the points that serve as the reference coordinates are reference points, which are usually handwritten at the four corners of the drawing.

A figure is drawn using each grid as a reference, and when the figure input processing device automatically reads and performs recognition processing, the recognition process is performed by assuming a grid based on the reference point. The extraction accuracy of is important.

FIG. 2 shows marks commonly used as reference points in the past.

Conventionally, data is read by a graphic input processing device;
Display the converted image data on the display,
A person used a light pen or a cursor to indicate the center of the intersection of the "+" marks as a reference point.

[Problems to be Solved by the Invention] According to the above conventional method, a human observes the points shown in FIG. Was.

Figures, including reference point marks, are generally drawn with a 0.5mm sharpener, and the thickness of the lines will vary depending on the individual. When the line width (Lx ₁ , Ly ₁ ) increases and the center line deviates from the reference point, the deviation is generally large and the accuracy of extracting the reference point decreases, causing the problem that high accuracy cannot be guaranteed. .

The present invention aims to provide a method for determining a reference point with high accuracy.

[Means for Solving the Problems] The above problem is that in a figure input processing device that reads a drawing and recognizes and processes the figures drawn in the drawing, it is difficult to calculate the coordinates of a reference point that should be in a predetermined area of the drawing. When determining, a predetermined L-shaped line and the L-shaped line
A bent part of the line in the shape of a letter and a predetermined inverted L-shaped line having an opposing bent part are detected, and the line segment Determine the X coordinate as the center of the airspace width or overlapping width of the two line segments, and determine the Y coordinate as the center of the airspace width or overlapping width of the two line segments that are almost perpendicular to the two line segments. However, this problem is solved by the reference point extraction method of the present invention, which is constructed so that a point determined by the determined X and Y coordinates is used as a reference point.

[Function] In other words, a "+" mark was previously drawn as a reference point, but this is now drawn as a combination of two L-shaped marks (an L-shaped line and an inverted L-shaped line).
Both the X and Y coordinates of the air space between the line segments of the two L-shaped marks or the center of the overlap width between the line segments are extracted, and the intersection thereof is extracted as a reference point.

The two L-shaped marks can be made by using a template such as the one illustrated in Figure 3, so that the orthogonal grid lines (indicated by dashed lines in the figure) at the reference point on the drawing pass through the center of the template window as shown. By placing the template so that it can be seen as if it were straight, and drawing the marks closely to each overhang line on one side of the L-shape of both windows, it is easier to draw marks than when using a template for +-shaped windows to draw conventional +-shaped marks. , two marks can be drawn with uniform pen pressure relatively easily. As a result, the width of the airspace between two almost parallel lines, or the center of the overlap width, comes close to the grid line passing through the grid point passing through the reference point, making it easy to extract the reference point with high precision. Can be done.

[Example] The gist of the present invention will be specifically explained below with reference to an example shown in FIG.

FIG. 1 is a diagram illustrating a reference point extraction method according to an embodiment of the present invention. As shown in the figure, the reference point mark is drawn as a combination of two L-shaped marks.

Figure 1a is drawn so that there is an air space between the two L-shaped marks, and Figure 1b is drawn so that there is an air space between the two L-shaped marks.
The lines of the L-shaped mark are drawn so that they overlap.

When extracting the reference point, the image data read by _the graphic input processing device and _binarized is displayed on the display. and extract it as a reference point.

In the case of Figure b, the intersection of the center lines of the overlaps Lx ₃ and Ly ₃ is extracted as the reference point.

Generally, the width of the air space Lx ₂ , Ly ₂ or the overlapping portion Lx ₃ , Ly ₃ formed by two line segments can be drawn smaller than the width of the line segment (Ll ₁ , Ly ₁ in Figure 2),
Therefore, reference points can be extracted easily and with high precision.

In particular, when the dimensions of Lx ₂ , Ly ₂ , Lx ₃ , and Ly ₃ correspond to the reading resolution of the scanner of the graphic input processing device (usually about 0.1 mm), that is, 1 dot,
It can be input as is as a reference point.

[Effects of the Invention] As described above, according to the present invention, reference points for figure recognition processing can be easily and accurately extracted, and the practical effects thereof are significant.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram for explaining an embodiment of the present invention, and FIG. 2 is a conceptual diagram for explaining a conventional example. FIG. 3 is a diagram illustrating an embodiment of the present invention using a template. In the drawing, Lx ₁ and Ly ₁ are the widths of the line segments, Lx ₂ and
Ly ₂ indicates the air space width between the line segments, and Lx ₃ and Ly ₃ indicate the overlap width between the line segments.

Claims (1)

[Scope of Claims] 1. In a figure input processing device that reads a drawing and recognizes and processes figures drawn in the drawing, when determining the coordinates of a reference point that should be in a predetermined area of the drawing, a predetermined L Detecting a predetermined inverted L-shaped line having a bent part opposite to the bent part of the L-shaped line, and detecting two substantially parallel lines of the L-shaped and inverted L-shaped lines. For the line segment, determine the X coordinate as the center of the airspace width or overlap width of the line segment, and determine the airspace width or overlap width of the two line segments for two line segments that are almost perpendicular to the two line segments. A reference point extraction method characterized in that the Y coordinate is determined as the center of the width, and the point determined by the determined X and Y coordinates is set as the reference point.