JPH07120361B2 - Contact symbol separation method for mechanical drawings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Regarding a contact symbol separation method of a mechanical drawing in automatic drawing input for automating the process of inputting a mechanical drawing to a computer, various symbols entered by contacting on a leader line in the mechanical drawing With the aim of providing a contact symbol separation method for machine drawings that can be correctly separated and recognized, after the machine drawings are read and the image is vectorized, there are isolated and non-isolated figures due to the connection relationship between the vectors. In the contact symbol separation method of the mechanical drawing in the drawing input device that classifies each figure and performs the identification process for each figure, in the leader line extraction unit for the data in the non-isolated figure data storage unit, the undefined arrow determination unit and the leader line determination unit Extract the leader line connected to the arrow and extract the horizontal (vertical) baseline for the extracted leader line in the baseline determination unit. broth,
The contact symbol determination / separation unit determines whether or not the line segment of the open end point is oblique by the open end point line segment determination means of the line segment connected to the extracted base line. The means determines the presence of a contact symbol in the middle portion of the baseline, and when the contact symbol is oblique, determines the symbol at the end of the baseline by the baseline end symbol determining means and separates the determined symbols.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact symbol separation method for mechanical drawings in automatic drawing input for automating the process of inputting mechanical drawings into a computer.

In recent years, CAD systems have been rapidly introduced in many manufacturing fields for the purpose of improving the efficiency of design work. In that case, automatic drawing input is expected for the design drawing, especially for the mechanical drawing with the largest number of drawings.

The applicant of the present invention has already referred to a "character string-corresponding line segment extraction method" (Japanese Patent Application No. 61-257499) for recognizing characters while taking a correspondence relationship between a line figure and character information written along the line drawing automatic input device. No.) and a center line used for design drawings and a broken line for displaying a hidden line (representing a structure that cannot be seen from the surface) and a “dashed line / chain line extraction method” (Japanese Patent Application No. 62). -151605) and other related inventions proposed.

According to these proposed methods, it is possible to extract the line segment corresponding to the character string and the center line and the hidden line. However, it was instructed by touching the leader line among the graphic elements. The symbols could not be separated and extracted.

Therefore, it has been desired to automate the separation of contact symbols in mechanical drawings.

[Prior Art] FIG. 4 shows an explanatory diagram of a conventional method.

In FIG. 4, 40 is a drawing reading unit, 41 is a vectorization unit, 42 is an isolated / non-isolated classification unit, 43 is an isolated figure classification unit, 44 is a non-isolated figure recognition unit, 45 is a character string recognition unit, Reference numeral 46 represents a hidden line / center line recognition unit, and 47 represents a character corresponding line segment recognition unit.

To explain the operation, the drawing reading unit 40 reads the drawing from the scanner, performs processes such as noise removal and hole filling, and after the image is thinned, the vectorization unit 41 vectorizes it by polygonal line approximation to show the connection relationship between the vectors. Ask. Next, in the isolated / non-isolated classifying unit 42, those having a relatively small rectangular area surrounding the connected vector set are classified as isolated figures, and the others are classified as non-isolated figures.

For the isolated figures thus obtained, the isolated figure classification unit
Processed at 43. The isolated figure includes a character and a part of a broken line / dashed line, and the isolated figure classification unit 43 classifies the character candidate into a character candidate and a broken line / dashed line candidate based on the situation around each area.

For the character candidates, the character string recognition unit 45 extracts the character string and performs character recognition.For the broken line / chain line candidates, the hidden line / center line recognition unit 46 checks the continuity with the non-isolated figure, and writes with broken lines. Recognize the hidden line and the center line drawn by the solid line or the one-dotted chain line (by the "dashed line / chain line extraction method" proposed by the present applicant).

The non-isolated figure recognition unit 44 obtains a line segment that can be associated with the character candidate obtained by the isolated figure classification unit 43 (by the "character string correspondence line segment extraction method" proposed by the applicant of the present invention). The line segment that has obtained the correspondence is used as a dimension line (character strings are attached in close proximity) or a leader line (a line with an arrow and a bend), and a figure connected to the end point of the dimension line Recognize figures sequentially, such as using arrows and dimension extension lines. In addition, an outline having a closed figure is set as the outline, and other lines are left as undefined line segments whose attributes cannot be determined.

[Problems to be Solved by the Invention] In the above-described conventional method, only floating symbols in mechanical drawings are targeted, and there is no technique for extracting contact symbols. That is, an example of the contact symbol is shown in FIG. Is a symbol that indicates I-type group welding on one side (the other side), b. On both sides (opposite side and this side)
Symbols indicating I-type group welding of C. Is a symbol that indicates fillet welding on one side, d. Is a symbol that indicates fillet welding on both sides. Is a symbol indicating K group welding, f. Is a symbol written at the end of the arrow to indicate projection welding. And Ji. Is a symbol indicating finishing. As is clear from these examples, the contact symbols mainly include symbols indicating welding and symbols indicating finishing.

Since it was not possible to extract such contact symbols, conventionally,
There is a problem that the automatic input function of the mechanical drawing is incomplete because the contact symbol cannot be entered in the drawing or is not recognized correctly even if it is entered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a contact symbol separation method for a mechanical drawing that can correctly recognize and separate various symbols written on a drawing by touching a leader line.

[Means for Solving the Problems] FIG. 1 shows a basic configuration diagram of the present invention.

In FIG. 1, 10 is a non-isolated figure data storage unit, 11 is a leader line extraction unit, 12 is a base line determination unit, 13 is a contact symbol determination / separation unit, 14 is a symbol recognition unit, 15 is a leader line candidate storage unit, Reference numeral 16 represents a contact symbol candidate storage unit.

The non-isolated graphic data storage unit 10 has the same contents as the contents held by the non-isolated graphic recognition unit 44 described with reference to the conventional system illustration in FIG. The leader line extraction unit 11 is composed of an undefined arrow determination unit 111 and a leader line determination unit 112, and the contact symbol determination / separation unit 13 is an open end dotted line segment determination unit 131.
It comprises a baseline middle part symbol determination means 132 and a baseline end part symbol determination means 133.

The present invention extracts a leader line with an arrow based on non-isolated figure data, identifies the baseline, and determines and separates a contact symbol in the middle part of the baseline and a contact symbol in the final terminal part of the baseline. To do.

[Operation] With respect to the data stored in the non-isolated figure data storage unit 10, the leader line extraction unit 11 extracts a leader line. In this case, when the undefined arrow is determined by the undefined arrow determination means 111, the leader line determination means 112 determines whether the line segment connected to the arrow is a leader line.

If it is a leader line, it is stored in the leader line candidate storage unit 15. The next baseline determination unit 12 extracts the leader line candidate from the leader line candidate storage unit 15 and determines the horizontal (or vertical) baseline from the diagonal line with the arrow. The determined baseline information is supplied to the next contact symbol determination / separation unit 13.

The contact symbol determination / separation unit 13 traces the base line and determines whether the line segment having the open end point is oblique or not (horizontal or vertical) by the open end point line segment determination means 131.
In this determination, if it is determined that the contact mark is not oblique, the baseline intermediate portion symbol determining means 132 determines whether or not there is a contact symbol in the baseline intermediate portion. When the open end dotted line segment determining means 131 determines that the line is oblique, the baseline end symbol determining means 133 determines whether or not there is a contact symbol at the end of the baseline.

When the determination means 132 and 133 determine that there is a contact symbol, the line segment data is separated and output to the symbol recognition unit 14.

The symbol recognition unit 14 recognizes and outputs the type of each symbol data by a known technique such as pattern matching.

[Embodiment] FIG. 2 shows a process flow chart of an embodiment of the present invention.

FIG. 2 shows a processing flow for realizing each means of the basic configuration of the present invention shown in FIG.

First, the contact symbols will be described. An example of the contact symbols is shown in FIG. 5. The contact symbols will be described with reference to FIG. The line segment 30 marked with an arrow is written at an inclination of about 60 ° with respect to the horizontal line, and a horizontal base line 31 is connected to the tip of the line segment 30 in the drawing, but the base line may be vertical. The contact symbol may be written at positions indicated by A and B in the middle portion of the base line, or may be written at positions indicated by C at the terminal end portion. When the baseline is vertical, A and B are located to the left and right of the baseline, and C is located above.

Referring to FIG. 2, first, a process for detecting an undefined arrow is performed (200 in FIG. 2), and when detected, the line segment connected to the arrow is sequentially traced, and the line segment has a bending point ( same
220), if there is an open end point (the end is interrupted) (at 230), the line segment is stored in the storage unit as a leader line candidate.

Next, base line detection is performed on the line segment of the leader line candidate, and it is determined whether or not the line segment at the tip (open end point) of the base line is oblique (step 260).

As a result, when the line segment with the open end point is diagonal, it is assumed that there is a symbol at the end of the baseline, and the frame composed of the diagonal line segment and the line segment intersecting with it has a preset size. It is judged whether or not it falls within the frame of (No. 270). If the size is within the frame, the diagonal line segment (including the crossing line segment) is determined as a symbol and separated. An example of symbols discriminated by this discrimination method is shown in FIG. Is the case.

If it is determined in step 260 that it is not oblique (horizontal or vertical), the process moves to step 290, and the data of the base line (including the line segment connected to it) is stored as a contact symbol candidate. Explaining the case of the base line horizontal line below, it is determined whether or not there is a line segment that branches (connects) above the base line (at 300), and if there is, the branch line segment has a predetermined length (threshold: Th) Determine if it is less than or equal to. At this time, if multiple line segments are branched, the size of each line segment (for example, the length and the area of the space)
Is less than or equal to a predetermined threshold value. If these are less than or equal to a predetermined threshold value, the branched line segment is separated and output as a contact symbol (at step 320).
An example of symbols discriminated by this discrimination method is shown in FIG. C. And b. This is the case for the symbols above.

By the same method, in steps 330 to 350, it is determined whether or not a contact symbol is written for a line segment that branches below the base line, and if it is written, a process of separating it is performed. An example of separation based on this determination is shown in Fig. 3B. This is the case for the symbols at the bottom of.

The outline of FIG. 3 (b) is as follows. Shows an example of I-shaped group welding (one side). In this case, two line segments branched from the base line are detected, and the length l _{1 of the} line segment is a threshold value.
If it is smaller than Th, these two line segments are separated as contact symbols. As the threshold value Th, a value of 6 (millimeter), which is a specific example, was used.

Next, in FIG. Indicates the symbol of K-type group welding. In this case, line segments in the orthogonal direction and line segments in the diagonal direction are detected from the base line, and their lengths are l ₂ to l _{5 as} shown in the figure.
Are smaller than the threshold Th, the line segments are identified as contact symbols and separated. C. In the case of a symbol that indicates fillet welding, the line segment in the orthogonal direction and the diagonal direction branched from the base line is detected, and the length l ₆ of the line segment in the orthogonal direction and the branch point and the diagonal of the line in the orthogonal direction are detected. Regarding the distance l ₇ to the point connecting with the base line of the direction line, And b. Threshold as well
When it is smaller than Th, it is identified as a contact symbol and separated.

D. Fig. 5 f. An example of the projection welding shown in is shown. The contact symbol written on the end portion of the leader line is discriminated and separated in steps 260 to 280 of FIG. 2, and specifically, the leader line ends with an oblique line.
At this time, the line segment (oblique line segment) connected to the baseline is taken out, and its maximum and minimum coordinate positions (MAX X, MAX Y),
(MIN X, MIN Y) is obtained, and it is determined whether or not the value is within a predetermined threshold value (within a rectangular frame).

[Effects of the Invention] According to the present invention, since the contacting symbols can be separated and extracted by using the baseline information of the leader line, even if the symbol information that contacts the leader line is written in the mechanical drawing in addition to the floating symbol, it is automatically input. You can

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a process flow diagram of an embodiment of the present invention, FIG. 3 (a) is a diagram showing an arrangement position of contact symbols, and FIG. 3 (b) is various types. FIG. 4 is a diagram showing a method of discriminating a contact symbol, FIG. 4 is a system explanatory diagram of a conventional example, and FIG. In FIG. 1, 10: Non-isolated figure data storage section 11: Lead line extraction section 12: Base line determination section 13: Contact symbol determination / separation section 14: Symbol recognition section 15: Lead line candidate storage section 16: Contact symbol candidate storage Department

Claims (1)

[Claims] 1. A contact symbol of a mechanical drawing in a drawing input device which reads a mechanical drawing, vectorizes an image, and then classifies the graphic into an isolated figure and a non-isolated figure according to a connection relationship between the vectors and performs identification processing for each figure. In the separation method, undefined arrow determination means (111) is applied to the data in the non-isolated figure data storage unit (10) in the leader line extraction unit (11).
And a leader line determination means (112) extracts a leader line connected to the arrow, and a base line determination unit (12) extracts a horizontal (vertical) baseline for the extracted leader line, and a contact symbol determination / separation unit (13). ) Determines whether or not the line segment of the open end point is oblique by the open end point line segment determination means (131) connected to the extracted base line, and when it is not oblique, the baseline middle part symbol determination means (131). 132) determines the presence of a contact symbol in the middle of the baseline, and when it is oblique, determines the symbol at the end of the baseline by the baseline end symbol determination means (133) and separates the determined symbols. Separation method for contact symbols on mechanical drawings.