JPH0532786B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] For example, drawings of machines and structures drawn based on certain conventions such as the projection method using the first angle method or the third angle method were originally drawn by humans. Because it is used to look at it and use it to judge the shape and structure of the object in question, other side views (in this specification, for example, front view , a side view, and a plan view, drawings of the same object drawn independently in different projection directions are called surface views, respectively), and by describing them, When a drawing becomes complicated and, in fact, makes it difficult to understand the structure of the object, hidden lines and the like that should normally be displayed on the drawing are often omitted. As described above, there has been a problem in that drawings with omitted parts cannot be reliably dealt with using conventional drawing recognition techniques.

In order to solve these conventional problems, the present invention detects pre-shield points by checking the consistency of image data related to input surface views, and
A technique for generating line segments to be further supplemented is disclosed.

[Industrial Application Fields] In recent years, the introduction of CAD systems in design work in various fields has been effective in reducing the number of man-hours required for the development of various products. Under such circumstances, currently,
The biggest problem with the operation of this CAD system is inputting design information into a computer.

The present invention is a drawing recognition system that aims to improve the efficiency of inputting design information into a CAD system by reading a drawing drawn by a designer as an image and automatically extracting design information from the image data using pattern recognition technology. Regarding equipment. Particularly related to automatic drawing input devices for mechanical drawings, structural drawings, etc. drawn using projection methods, from the drawing of design drawings to inputting design information into a computer and passing it on to the actual manufacturing process using a CAD system. It is applied to a consistent system up to the creation of processing information (NC tape). This technology can be used in a wide range of fields, such as mechanical drawings and structural drawings, in which design drawings are drawn using projection methods.

[Prior Art] Generally, mechanical drawings and drawings of structures are drawn using a projection method such as the first angle method or the third angle method.

FIG. 7 is a diagram illustrating the relationship between each side view when drawing by the third angle method, and 51 is a front view;
2 is a left side view, 53 is a right side view, 54 is a plan view,
55 is a bottom view, 56 is a rear view, 57 is an X axis, 58
represents the Y axis, and 59 represents the Z axis.

In other words, in the third angle method, the shape diagram in each direction by projection of the object is, for example, a front view 5, as shown in the same figure.
On the right side of 1, a right side view 53 of the object is drawn, and above the front view 51, a plan view 54 is drawn of the object as seen from above. (In the first angle method, the left side view is drawn to the right of the front view, and the bottom view is drawn above the front view, contrary to the third angle method.) Figure 8 is based on the third angle method. This is a diagram for explaining the display of the drawing, and a side view (front view) of an object having the shape shown in a when shown in a perspective view is shown in b. The right side view is as shown in c. At this time c
The surface indicated by 61 is expressed as a hidden line in b by a dotted line as indicated by 60.

[Problems to be solved by the invention] It is difficult for people to intuitively draw drawings using projection methods such as the first angle method and the third trigonometric method, which are used to draw mechanical drawings and structural drawings as described above. Line segments that represent a shape are often omitted when the shape can be easily understood, or when the description becomes too complex and difficult for people to understand.

FIG. 9 is a diagram illustrating an example of such line segment omission, in which the hole 64 seen in the front view 62 is
is indicated by a dotted line 65 in the right side view 63, while the surface indicated by 66 in the right side view 63 is correctly indicated by a dotted line 67 in the front view 62.

However, in these cases, the front view is often drawn as 68 and the dotted line 67 is omitted, or the right side view is drawn as 69 and the dotted line 67 is omitted.

Conventional drawing recognition systems cannot handle such abbreviated drawings. For this reason, the drawing information obtained by conventional drawing recognition devices is only a small part of the design information.
There was a problem that adding omitted line segments in the CAD system was too burdensome. Also,
Occasionally, a designer may make a description error when drawing. In such cases, conventional drawing recognition cannot deal with the problem, and it is unclear what kind of results to recognize and output, leading to problems such as lack of reliability.

In view of these conventional problems, the present invention provides a drawing recognition device that develops the shape of an object into a three-sided view, such as a mechanical drawing or a structural drawing, and draws the drawing using a simplified notation including omitted line segments. Understand the drawing methods using projection methods such as the first angle method and trigonometry, which are determined at the time of drawing in order to recognize shapes, recognize the position of each side view, and take the correspondence between the side views. By checking consistency, it is possible to point out areas where inconsistencies have occurred due to mistakes during drawing, reducing the work burden on subsequent CAD systems, and also recognizing the position and type of omitted line segments. However, it is an object of the present invention to provide a drawing recognition device that can obtain complete drawing information including omitted line segments.

[Means for Solving the Problems] According to the present invention, the above objects are achieved by the means described in the claims.

That is, the present invention is an apparatus for recognizing a drawing from image data related to a drawing created by developing the shape of a machine or structure using a projection method, and for identifying shape lines and auxiliary lines in the drawing. means for recognizing the positional relationship between adjacent surface views; means for determining the vertex position by normalizing the end point coordinates of the shape line on the X-axis and Y-axis for each surface view; Consistency is checked by referring to a knowledge base that rules out the correspondence between the surface views and checking the consistency between the surface views based on the correspondence between the normalized vertex positions and the number of vertices for each surface view, and detecting inconsistencies. When a contradictory point is detected by the consistency check section and the consistency check section, the type of line segment to be added is determined for the surface view having the vertex that does not satisfy the correspondence condition, and the type of line segment to be added is generated and added. This drawing recognition device includes a line segment generation unit.

[Operation] Until now, there has been no automatic drawing input device for machine drawings or structural drawings that recognizes design drawings in which line segments are omitted. The present invention registers the drawing method by projection as shown in FIG. Find the vertex, the coordinates of the vertex,
The Y-axis is normalized, the correspondence between the views is determined, and the consistency is checked. Next, as a result of the check, if there is an excess or deficiency of vertices between the corresponding sectional drawings, we will create a means to notify that there is a discrepancy, and we will determine the type of omitted line segment in the sectional drawings with many vertices, and This problem is solved by adding the line segments that are omitted in the side view.

[Embodiment] FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and the area within the dotted line indicates the technology of the present invention.

In the same figure, 1 is a means for identifying shape lines and auxiliary lines, and information on which the types of various line segments (attributes: outline lines, dimension lines, hidden lines, leader lines, etc.) have been identified is obtained by processing the previous number. It is received, identified into shape lines (outline lines, hidden lines) and auxiliary lines (dimension lines, leader lines, dimension auxiliary lines, . . . ), and stored in the auxiliary line data storage section 9 and the shape line data storage section.

Drawing position recognition means 2 is shape line data holding section 1
After grouping into connecting nets based on the shape line data of 0, the plan position is recognized for each group,
The result is also stored in the shape line data holding section 10.

The plan view vertex extraction unit 3 receives the data of the shape line whose plan view position is known from the shape line data storage unit 10, and extracts the coordinates of the end points of the shape line for each plan view, as shown in FIG. The coordinates are divided into the X axis and the Y axis, normalized so that those close to each other are treated as one vertex coordinate, and the vertex position and number of vertices are determined. Next, the consistency check section 4
Using the correspondence between the plan views based on the projection method as shown in FIG. 7, the vertex information obtained by the top plan vertex extraction section 3 is checked for consistency as shown in FIG. In the example of FIG. 3, a correspondence relationship is established between the Y-axis of the A-side view and the Y-axis of the B-side view. In this example, the number of vertices on the Y axis of the A-side view is _na , and the number of vertices on the Y-axis of the B-side view is _nb , and _na and _nb are not equal and there is no consistency. Furthermore, when checking the consistency of the mutual vertex positions, it is found that the vertex of _Y'2 in the B view is a mismatch point, and there is a contradiction. When such a contradictory part is found, it is output to the dialogue processing device 7 or the contradictory part list 8 in FIG. 1 to notify it.

The omitted line segment type/section extraction unit 5 and omitted line segment addition unit 6 in FIG. 1 perform processing when there is an instruction for omitted line segment addition processing.

These processes will be explained below.

First, the omitted line segment type/section extraction unit 5 estimates that there is an omitted line segment at that point when there is a contradictory point, and determines whether the shape line that is thought to be omitted is an outline line or a hidden line. , and then find the omitted line segment. First, to identify the type of omitted line segment, focus on the mismatch in the apex position as shown in b using the corresponding axis shown in Fig. 4 a as a reference, and then move it to the side of the plan view where the mismatch point is located as shown in c. A perpendicular line is drawn from the opposite axis as shown in the figure, and it is determined whether there is another shape line (within the same plane view) that intersects in the section up to the vertex of the point of mismatch. If there is an intersection as shown in c, it is determined to be a hidden line, and if there is no intersection as shown in d, it is determined to be an outline line. Next, there are two methods for extracting the additional section of the omitted line segment.
One of them is the center line 11 as shown in FIG.
(Obtained from the auxiliary line data.) A means of investigating the range where ``(obtained from the auxiliary line data)'' is written and finding the section that intersects the shape line within that range as an additional section. Second, as shown in Figure 6, ignore the center line and simply scan the mismatch points (missing side) between surface drawings 12 and 13 and find all the positions that intersect with the shape line from the corresponding axis side. In this method, numbers are sequentially given to the intersection positions with the shape line, and the area between odd numbers and even numbers is set as an additional section, and the area between even numbers and odd numbers is set as an additional section. It is possible to specify in advance which one to take, or it is also possible to receive instructions each time by making an inquiry to the dialog processing device 7 in FIG.

The omitted line segment adding section 6 in FIG. 1 is for adding an omitted line segment to the shape line data in the shape line data holding section 10 according to the above processing results.

[Effects of the Invention] As explained above, according to the present invention, design drawings can be improved by automatically extracting and recognizing omitted shape line segments in projection drawings such as mechanical drawings and structural drawings. It is possible to extract all drawing information from In addition, by notifying the subsequent CAD system of the locations of omitted line segments and contradictory locations, it is possible to reduce the work load up to the CAD terminal and reduce the number of man-hours required to obtain machining information. .

[Brief explanation of the drawing]

Figure 1 is a functional block diagram showing an embodiment of the present invention, Figure 2 is a diagram explaining vertex normalization, Figure 3 is a diagram explaining consistency checking, and Figure 4 is a diagram explaining lines to be added. Figure 5 is a diagram explaining the recognition of the type of minute, Figure 5 is a diagram explaining an example of adding omitted line segments depending on the center line section, Figure 6 is the line segments that should be added not only to the center line. 7 is a diagram explaining the relationship between the drawings in the third angle method. FIG. 8 is a diagram explaining the display of the drawings according to the third angle method. FIG. 2 is a diagram illustrating an example in which display of line segments is omitted on the drawing. 1... Means for identifying shape lines and auxiliary lines, 2... Means for recognizing the plan position, 3... Vertex extracting section of the plan view, 4... Consistency checking section, 5... Extracting section for type/section of omitted line segments, 6 ...Additional part of omitted line segment, 7...Dialogue processing device,
8... Conflict point list, 9... Auxiliary line data holding unit,
10... Shape line data holding unit, 11... Center line, 1
2, 13...Front view.

Claims (1)

[Scope of Claims] 1. A device for recognizing a drawing from image data related to a drawing created by developing the shape of a machine or structure using a projection method, which identifies shape lines and auxiliary lines in the drawing. means for recognizing the positional relationship between adjacent surface views; means for determining the vertex position by normalizing the end point coordinates of the shape line on the X-axis and Y-axis for each surface view; Consistency checks consistency between surface views based on the correspondence between the normalized vertex positions and the number of vertices for each surface view, while referring to a knowledge base that rules out the correspondence between surface views. When a contradictory point is detected by the consistency check section and the consistency check section, the type of line segment to be added is determined and generated for the surface view having the vertex that does not satisfy the correspondence condition. A drawing recognition device comprising: an additional line segment generation unit. 2. In a plan view in which line segments to be displayed are omitted, when a center line exists, the end point of the line segment to be added is determined within the section where the center line is drawn. Drawing recognition device. 3. In a plan view where line segments to be displayed are omitted, if there are multiple candidates for sections of line segments to be added, notify the operator of this and add additional sections according to the operator's instructions. A drawing recognition device according to claim 1 or 2, which determines the drawing recognition device.