JPH05751B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is a drawing reading device that can easily read only building figures from a drawing (such as a blank map) in which building figures and street figures are drawn. Moreover, the present invention relates to a method for extracting building figures in a drawing reading device, which enables recognition and extraction in a short time.

(Prior Art) Conventionally, when a drawing (hereinafter referred to as a blank map) in which a building figure A and a street figure B are drawn as shown in FIG. 7 is read into a drawing reading device, line segments are converted into vectors. Although it was possible to extract closed figures using Therefore, the following two methods are used to read a blank map as shown in FIG. 7 into a drawing reading device and create data that allows buildings to be distinguished from streets. That is, the first method is to have a drawing reading device read a blank map as shown in Figure 7, vectorize the line segments, extract closed figures, and then input the data into a CAD system, etc. send to
This is a method in which the operator specifies all buildings one by one using a digitizer or the like. The second method is to create a street map B consisting of only streets as shown in Figure 8 and a building map A consisting only of buildings as shown in Figure 9 from a blank map as shown in Figure 7. In this method, these are read separately by a drawing reading device, subjected to necessary processing such as vectorization, and then combined.

However, the former method requires all buildings to be
Since the operator has to visually check and make decisions while specifying the items, a large number of operators and a large amount of processing time are required. Furthermore, in the latter method, because the blank maps that are generally available on the market include both streets and buildings, a lot of tracing time is required to separate them into street maps and building maps.

(Problems to be Solved by the Invention) As described above, when identifying street maps and building maps using the conventional method, a large number of operators and a large amount of processing time are required. Another problem is that a lot of tracing time is required, resulting in a very long time to read the blank map.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to easily extract only building figures from a drawing in which building figures and street figures are drawn, without bothering the operator. Moreover, it is an object of the present invention to provide a highly reliable building figure extraction method using a drawing reading device that can recognize and extract in a short time.

[Structure of the Invention] (Means and operations for solving the problems) In order to achieve the above object, the present invention provides a drawing reading scanner that reads drawings and analyzes drawing data read by this drawing reading scanner. When extracting building shapes from a drawing in which building shapes and street shapes are drawn using a drawing reading device consisting of an image processing device that analyzes data, and an output device that outputs data analyzed by this image processing device, Line segments are thinned and vectorized from the read drawing data to extract closed shapes, and if any of the extracted closed shapes is in contact with itself at a point or line, the inside of the closed shape is Then, from the closed figures other than the closed figures that were excluded from the target, a closed figure to be inspected for the building is extracted based on the inclusion relationship of its circumscribed rectangle, and this extracted closed figure to be inspected for the building is used as a comparison target. Connect the shortest parts of the closed figures with a line segment,
The present invention is characterized in that it is determined whether or not this line segment is traced inside a closed figure to be compared, and as a result, a closed figure that can be traced is extracted as a building figure.

(Example) The present invention extracts all closed shapes that may constitute a building when only building shapes are recognized and extracted from a drawing in which building shapes and street shapes are drawn. By determining the topological positional relationship among these extracted closed figures and removing those that do not satisfy the building conditions as excluded, a set of closed figures representing the building is finally obtained as a building figure. This is how it was done.

An embodiment of the present invention based on the above concept will be described below with reference to the drawings.

FIG. 1 shows in block form an example of the configuration of a drawing reading device to which the present invention is applied. In FIG. 1, 1 is a drawing reading scanner that reads a blank map, which is a drawing on which the above-mentioned building figure A and street figure B are drawn, and 2 is the drawing data read by this drawing reading scanner 1, the details of which will be described later. The image processing device 3 that is analyzed by the method of the present invention is an output device that outputs the data analyzed by the image processing device 2.

Next, a method of extracting only the building figure A from a blank map on which the building figure A and street figure B as shown in FIG. 7 described above are drawn using the drawing reading device configured as described above will be described.

First, in step S1, the blank map shown in FIG. 7 is read by the drawing scanner 1. Next, the image processing device 2 thins the line segments and vectorizes the read data in step S2, and then extracts a closed figure as shown in FIG. 3 in step S3. Then, in step S4, as shown in FIGS. 4a and 4b, if there is a closed figure in contact with itself at a point or line, the inside of the extracted closed figure is excluded from the closed figure. Next step
In S5, a closed figure to be inspected for the building is extracted from the closed figures that satisfy the above conditions by the inclusion relationship of the circumscribed rectangle using the "closed figure inclusion relationship determination method". Select only the closed shapes that do not contain them and extract them as closed shapes to be inspected for the building. As a result, the inclusion relationship can be investigated from the inclusion relationship of the circumscribed rectangle.
Closed figures 11-12, 11-13, 11 in Figure 3
-14, 12-13, 21-22, 21-23,
There are 7 types, 21-24.

In this case, taking the investigation of the inclusion relationship of the now closed figures 11-12 as an example, in accordance with the "inclusion relationship determination method for closed figures" in FIG. From inside, closed figure 11 that is the object of the building investigation and is the subject of comparison.
- 12 are connected by the virtual line segment 31, and further, in step S7, the inside of each closed figure 11, 12,
Track the outside respectively. When tracing the inside of the closed figure 11, the traced wall surface changes to the outside of the closed figure 12 due to the virtual line segment 31. That is, the closed figure 11 includes the closed figure 12. Therefore, the closed figure 11 is excluded from the building figures.

Next, let us take as an example the investigation of the inclusion relationship of the closed figure 12-13. Similarly to the above, when considering the virtual line segment 32 as shown in FIG. 6 and tracing the line segment inside the closed figures 12 and 13, each closed figure 12 and 13 is It is possible to track only the inside of both. That is, closed figure 12
and the closed figure 13 are not in an inclusive relationship and do not contain any other closed figure. Therefore, in step S8, closed figures 12 and 13 are determined as building figures.

As described above, by extracting all closed figures and determining their contact points and inclusion relationships, a set of building figures A as shown in Fig. 9 is obtained, and these are outputted from the output device 3 in step S9. The building data will be output.

As described above, in this embodiment, there are a drawing reading scanner 1 that reads drawings, and an image processing device 2 that analyzes drawing data read by this drawing reading scanner 1.
When extracting building figure A from a blank map on which building figure A and street figure B are drawn, using a drawing reading device consisting of a First, line segments are thinned and vectorized from the read drawing data to extract closed shapes, and if any of the extracted closed shapes is in contact with itself at a point or line, the inside of the closed shape is , and then from among closed shapes other than the closed shapes that were removed from this target,
A closed figure to be investigated for a building is extracted based on the containment relationship of the circumscribed rectangle, and the shortest part of the closed figures to be compared is connected with a line segment, and this line segment is the object to be compared. It is determined whether or not a closed figure can be tracked inside, and as a result, a closed figure that can be tracked is extracted as a building figure.

Therefore, regardless of the size and shape of the building figure A, only the building figure A can be easily drawn from a blank map on which the building figure A and the street figure B are drawn, without any operator intervention, and in a short time. It is possible to recognize and extract the This reduces the reading time of blank map data with building attributes.
This makes it possible to significantly shorten the time.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without changing the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, closed figures are extracted by thinning and vectorizing line segments from read drawing data, and points or lines are added to the extracted closed figures. If there is a closed figure that is in contact with itself, remove the inside of the closed figure from the target of the closed figure, and then select the closed figure to be inspected for the building based on the inclusion relationship of its circumscribed rectangle from among the closed figures other than the closed figure that was excluded from the target. Connect the shortest parts of the extracted closed figures to be compared with a line segment, and determine whether this line segment is traced inside the closed figure to be compared. As a result, closed shapes that can be traced are extracted as building shapes, so that only building shapes can be easily extracted from a drawing in which building shapes and street shapes are drawn without bothering the operator. Moreover, it is possible to provide a building figure extraction method using an extremely reliable drawing reading device that can recognize and extract in a short time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration example of a drawing reading device to which the present invention is applied, FIG. 2 is a flowchart for explaining the building figure extraction method according to the present invention, and FIG.
4a, b, 5, and 6 are diagrams for explaining the individual processing contents in FIG. 2, respectively, and FIG. 7 is a diagram showing an example of a blank map that is a drawing to be read,
8 is a street diagram showing only the street portion of the drawing to be read in FIG. 7, and FIG. 9 is a building diagram showing only the building portion of the drawing to be read in FIG. 7. A... Building, B... Street, 1... Drawing reading scanner, 2... Image processing device, 3... Output device, 11
~14,21~26...Closed figure, 31,32...
Virtual line segments, 41-43...Tracing lines.

Claims (1)

[Claims] 1. A drawing reading device consisting of a drawing reading scanner that reads drawings, an image processing device that analyzes the drawing data read by this drawing reading scanner, and an output device that outputs the data analyzed by this image processing device. In the method of extracting building shapes from a drawing in which building shapes and street shapes are drawn, line segments are thinned and vectorized from the read drawing data to extract closed shapes, and in the extracted closed shapes, ,
If there is a closed figure that is in contact with itself at a point or line, remove the inside of the closed figure from the object of the closed figure, and then use the inclusion relationship of the circumscribed rectangle to create a building from within the closed figure other than the closed figure that was excluded from the object. A closed figure to be investigated is extracted, and the shortest parts of the closed figures to be compared are connected with a line segment in this extracted closed figure to be investigated, and this line segment is traced inside the closed figure to be compared. 1. A building figure extraction method in a drawing reading device, characterized in that a closed figure that can be traced is extracted as a building figure.