JPS63104190A - Drawing read system - Google Patents

Abstract

PURPOSE:To speed up recognition processing by providing a dictionary which stores a specific figure that an operator wants to recognize as combinations of basic graphic elements. CONSTITUTION:A binarization means 12 binarizes a figure read out of a drawing 11. The binary picture data is stored in a binary picture storage means 13, and handed to a basic graphic element recognition means 14. First, it converts the binary picture data into short vector data, obtains vector data from the short vector data and recognizes basic graphic elements. The recognized basic graphic elements and parameters such as their coordinates and sizes are stored in a drawing basic graphic element group storage means 15. A specific figure recognition means 17 compares a set of basic graphic elements which are read out of the drawing and outputted from the drawing basic graphic element group storage means 15 with a set of basic graphic elements of a specific figure in a dictionary, which is outputted from a dictionary storage means 16, calculates a degree of similarity as a difference, evaluates it and recognizes the specific figure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drawing reading method for detecting a predetermined figure in a drawing and recognizing its shape.

[Conventional technology]

Figure 7 shows, for example, Information-technology Promotion Association Technology Center Report 5.
This is a configuration diagram of a decision tree showing the conventional drawing reading method shown in 9-technique-043. These judgment boxes are used to classify specific figures, and have a hierarchical structure, and the feature amount from the feature extraction box 1 is received by the judgment box 2 in the highest hierarchy. 3
is a matching box that performs pattern matching by holding one group of classified specific graphic symbols, and is provided corresponding to each branch of the determination box 2 at the lowest level.

Next, the operation will be explained. A predetermined figure read from the drawing is sent to the feature extraction box 1 as binary image data. The feature extraction box 1 thins the received binary image data to create vector data, extracts feature quantities such as the number of closed curves and the number of open end points, and passes this to the determination box 2 of the largest hierarchy. In the judgment box 2, the predetermined figure is sequentially branched for each layer based on its feature amount, and the matching box 3 is selected from the judgment box 2 in the lowest layer.
Pass it to one of the

In this way, the matching box 3 to which the predetermined figure has been passed performs pattern matching between this and the symbols of the group it holds, thereby specifying and recognizing the symbol of the predetermined figure.

[Problem that the invention seeks to solve]

Conventional drawing reading methods are configured as described above, so when you want to add a specific figure type that you want to recognize, you need to know the type and number of feature values to be determined, as well as the number of symbol groups for pattern matching. must be increased,
There were problems such as the need to reconsider the specific method each time, and the recognition target area had to be extracted one by one.

This invention was made in order to solve the above-mentioned problems, and it provides a drawing reading method that does not require reconsideration of specific means when adding a specific figure type and speeds up the recognition of specific figures. The purpose is to obtain.

[Means for solving problems]

The drawing reading method according to the present invention has a dictionary that stores a plurality of specific figures to be recognized as combinations of basic figure elements, reads the drawing to be read as binary image data, and uses the binary image data to The figure read from the drawing is recognized as a basic figure element, and then the basic element of the same type as the largest element among the basic figure elements of the figure in the drawing is selected as the largest element among the basic figure elements of the specific figure. Select the one with the above as a candidate, compare it with the set of graphic elements of each candidate, and match the size by one rotation according to the ratio.

The alignment is performed and the mutual arrangement positions of basic graphical elements are evaluated as errors.

[For production]

The drawing reading method in this invention is a straight line and two circular arcs.

You can create a dictionary by collecting specific shapes that you want to recognize using basic graphical elements such as circles, triangles, and squares, and also compare the specified shapes read from the drawing with the specific shapes in the dictionary to determine the placement position among the basic graphical elements. A specific figure can be recognized by evaluating the error in the figure, and if you want to add a type of figure that you want to specify, you only need to express that figure with basic figure elements, and it is not necessary to reconsider the specific method. I don't. Note that the above-mentioned specific figure may be a similar figure that is an arbitrary enlargement ratio of the figure registered in the dictionary.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 11 is the drawing you want to read, 12 is this drawing 1
Binarization means 13 creates binary image data of the figure read from 1, binary image storage means 13 stores the binary image data from the binarization means 12, and 14 creates a straight line from the binary image data. 1 arc.

Basic geometric elements such as circles, triangles, and squares and their sizes.

Basic figure element recognition means for obtaining parameters such as position and direction; 15, drawing basic figure element group storage means for storing the basic figure elements and their parameters from the basic figure element recognition means 14; 16, when the specific figure to be recognized is a straight line 1; Dictionary storage means 17 stores a dictionary consisting of basic graphical elements such as arcs, triangles, squares, etc.; reference numeral 17 stores a set of basic graphical elements of drawing figures from the drawing basic graphical element group storage means 15; Specific figure recognition means 18 recognizes a specific figure by comparing it with a set of basic figure elements of a specific figure in the dictionary of the dictionary storage means 16 and evaluating the error between mutual basic figure elements; 18 is a specific figure recognition means 17; This is a recognition result storage means for storing recognition results.

Next, the operation will be explained. Here, FIG. 2 is a plan view showing an example of the drawing 11 to be read, and FIGS. 3 and 4 are explanatory diagrams showing the recognition process of its basic graphical elements.

Figures read from drawing 11 (for example, broken line 21 in Fig. 2)
The portion surrounded by ) is converted into binary image data by the binarization means 12. FIG. 3A shows this binary image data, and each black point 22 is given an X coordinate and an X coordinate as a position. This binary image data is stored in the binary image storage means 13.
and is passed to the basic graphic element recognition means 14.

The basic graphic element recognition means 14 first converts the binary iconographic data into short vector data, and then obtains vector data from the short vector data to recognize basic graphic elements. FIG. 3B shows this short vector data, and each short vector 23 has coordinates of a starting point and an ending point, and is obtained from a minute portion of a mass of black points 22 of the binary image data.

Moreover, FIG. 3C shows the connection relationship of each of these short vectors 23,
Vector data obtained from vector angle changes, etc.
Each side of the figure 21 read from the drawing 11 is recognized as a long vector )/F/24 having the coordinates of a starting point and an ending point.

Here, if the figure read from drawing 11 is a circle, it is recognized as a circle 26 defined by the center coordinates and radius shown in FIG. 4B from the short vector data 25 as shown in FIG. 4A. Straight line 2 circles 2 arcs recognized in this way,
Basic graphical elements such as triangles and squares and parameters such as their coordinates and sizes are stored in the drawing basic graphical element group storage means 15.

The specific figure recognition means 17 compares the set of basic figure elements of the figure read from the drawing from the drawing basic figure element group storage means 15 with the set of basic figure elements of the specific figure of the dictionary from the dictionary storage means 16, The degree of similarity is calculated as an error, and this error is evaluated to recognize a specific figure.

FIG. 5 is an explanatory diagram showing this recognition process, and FIG. 6 is a flowchart showing the flow of the process. FIG. 5A shows a figure read from a portion surrounded by a broken line 21 in the drawing 11, which is converted into basic figure elements into six line segments D1 to D60 on the right side.

In step ST1, the largest element among the basic graphical elements of this dictionary, for example, zl, is selected, and in step ST2, the largest element among the basic graphical elements of the drawing (for example, DI
) and restore the dictionary components that also have an element similar to this element as the largest element as candidates. The left side of Figure 5 is one of these candidates, 21~z6
It is converted into basic graphical elements into six line segments.

Steps ST4 to ST8 are error evaluation procedures for one candidate. Both of these selected in step ST4 are correlated, and as shown in FIG. 5B, the amount of parallel movement, amount of rotation, and enlargement ratio when basic graphic element D1 is moved to the position of basic graphic element z1 are obtained, Step S
The basic figure elements D2 to D6 remaining at T5 are shown in Fig. 5C.
As shown in the figure, the image is moved and scaled according to the amount of parallel movement and the amount of rotation.

Next, through a loop of steps STT and ST8, the basic graphical elements 22 to z5 of the dictionary are made to correspond to the basic graphical elements D2 to D5 of the drawing, and those with the minimum error are made into pairs, and the errors are cleared in step 1376. The total error is then added to the error area calculated as a total error.

Here, if the basic graphic element is a line segment, this error is calculated by defining it as the square of the distance between the end point of the line segment on the dictionary side and the end point of the line segment on the drawing side, for example, In the case of a circle, the square of the distance between the center positions and the square of the radius difference; in the case of a triangle, the sum of the squares of the distances between each of the three vertices; in the case of a square, the sum of the squares of the distances between each of the four vertices It is calculated by defining it as the sum of squares of the distances.

Next, the total error calculated in this way is compared with the previously calculated total error in step ST9, and only if it is small, the value is updated and the process returns to step ST3.

Here, the storage area for this total error has the initial value:
For example, the maximum value that can be stored is sected. At step ST3, where the process is returned, one of the remaining candidates is selected from among the saved candidates, and the same process is repeated thereafter.

In step ST10, the final remaining minimum total error is compared with a tolerance value. As a result, if it is smaller than the tolerance value, it is determined in step ST11 that the combination of basic graphic elements that obtained the minimum total error is the specific figure to be recognized, and post-processing is performed; if it is thicker than the tolerance value, In step 5T12, it is determined that there is no specific figure to be recognized, and post-processing is performed.

In steps 5T13 and 5T14, specified or unspecified basic graphic elements are deleted, and in step ST15, it is determined whether there are any remaining basic graphic elements. If there are any remaining figures, the process returns to step ST1 and starts specifying another figure.

In the above embodiment, a case has been described in which the error evaluation is performed in accordance with the coordinate system on the dictionary side, but the error evaluation may be performed in accordance with the coordinate system on the drawing side, and the same effect as in the above embodiment is achieved.

〔Effect of the invention〕

As described above, according to the present invention, since the configuration is such that the figure to be specified is represented by basic figure elements such as two straight circles, triangles, and squares, and the specific figure is recognized, even when adding the figure type to be specified, , there is no need to reconsider the specific means for recognition, and since the size is matched using the largest basic graphical element, it is possible to identify similar shapes using a dictionary. This has the effect of providing a reading method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a drawing reading method according to an embodiment of the present invention, FIG. 2 is a plan view showing an example of a drawing to be input,
FIGS. 3 and 4 are explanatory diagrams showing the recognition process of basic graphic elements in this invention, FIG. 5 is an explanatory diagram showing the recognition process of specific shapes in this invention, and FIG. 6 is a flowchart showing the flow of the process. , FIG. 7 is a configuration diagram of a decision tree showing a conventional drawing reading method. 11 is a drawing, 12 is a binarization means, 13 is a binary image storage means, 14 is a basic figure element recognition means, 15 is a drawing basic figure element group storage means, 16 is a dictionary storage means, 17 is a specific figure recognition means, D1 to D6 and z1 to z6 are basic graphical elements. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant: Mitsubishi Electric Corporation (2 others)

Claims (1)

[Claims] In a drawing reading method for detecting a predetermined figure in a drawing and recognizing its shape, a binary image storage means for storing binary image data of a figure read from the drawing;
a drawing basic figure element group storage means for storing basic figure elements obtained from value image data and parameters such as the size, position, direction, etc. of the basic figure elements; A dictionary storage means that stores a dictionary in which a plurality of basic graphic elements are registered as dictionary constituent elements, and the basic graphic element is the same type as the largest basic graphic element among the basic graphic elements of the figure read from the drawing. Select the dictionary component that has as the largest basic figure element as a candidate for the specific figure that you want to recognize, and for each of these candidates, size matching by proportion, translation and rotation are performed between the largest basic figure elements, and the figure read from the drawing is The combinations of basic figure elements of the specific figure in the dictionary are made to correspond in descending order of the basic figure elements, the errors between these two basic figure elements are calculated and summed, and the candidate for which this total amount is the smallest is recognized. A drawing reading method characterized in that a specific figure is determined to be a desired specific figure, a basic figure element corresponding to the specific figure is deleted from the basic figure elements of the drawing, and the above determination is repeated for the remaining basic figure elements of the drawing.