JPH05290162A - Diagram branch point connecting method for image input device - Google Patents

Abstract

PURPOSE:To accurately connect respective lines contacting a branch point of a graphic. CONSTITUTION:The graphic is read by a photoelectric conversion part 10 and inputted to a controller 12 through an A/D converter 11. The controller 12 stores a coordinate array data storage part 128 with vector data on the figure which are obtained through a line thinning process part 126 and an image tracking process part 127. A branch point is extracted from the vector data and when there are plural branch points, they are put together; and the directional line of each polygonal line contacting the branch point is calculated, a polygonal line having a directional line closer to 180 deg. than the directional line of one polygonal line is extracted. The directional line of the 1st polygonal line is extended by specific length and a directional line which is closer to 180 deg. is retrieved among directional lines which appear during the extension and the polygonal line having the directional line is connected to the 1st polygonal line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line figure branch point connecting method of an image input apparatus for connecting line figure branch points in drawing information processing using the image input apparatus.

[0002]

2. Description of the Related Art With the spread of so-called CAD systems,
An image input device has been proposed which reads an image drawn on a map, a circuit diagram, a design drawing, or the like by a photoelectric conversion device and converts the image data (raster data) into line data (vector data). The means for creating vector data by this image input device will be described with reference to FIGS.

FIG. 5 is a diagram showing a figure drawn on a recording sheet. In this figure, 1 is a recording paper, and 2 and 3 are figures drawn on the recording paper 1. The figure 2 is composed of a straight line connecting the points A ₁ and A ₂ and a straight line connecting the points B ₁ and B ₂ .
Further, the figure 3 is composed of four straight lines passing through the point C.

FIG. 6 is an enlarged view of the figure 2 shown in FIG.
Each straight line of the figure 2 has a line width w when drawn on the recording paper 1.
The line width w is represented by the number of pixels existing in the line width direction, and the number of pixels is determined by the line width w and the reading resolution of the photoelectric conversion device. The surface of the recording paper 1 is scanned by the photoelectric conversion device, and as a result, raster data of the graphic 2 and graphic 3 is obtained.

Next, thinning processing is performed based on this raster data. This thinning processing is performed by extracting the pixel row at the center of the line having the line width w, and tracing one feature point to the next feature point in the obtained pixel row, Vector data is created by extracting the coordinates of the set coordinate axes. Note that the feature points are end points, break points, and branch points of a pixel line subjected to the thinning process, and the branch points are three pixels out of eight pixels around the target pixel of the center line in the thinning process. The pixel having the center line as described above exists.

The line obtained as a result of the thinning process is the line drawn within the line width w in FIG. P ₁ , P ₃ , P ₅ , P ₇
Is the above end point, P ₂ , P ₄ , P ₆ and P ₈ are the above break points, P ₀₁ ,
P ₀₂ indicates the branch point. In addition, L ₁ is a line segment (a polygonal line) from the end point P ₁ to the branch point P ₂ to the branch point P ₀₁ , L ₃ is a line segment from the end point P ₃ to the branch point P ₄ to the branch point P ₀₁ , and L ₅
Is a polygonal line from the end point P ₅ to the branch point P ₆ to the branch point P ₀₂ , L ₇ is a polygonal line from the end point P ₇ to the break point P ₈ to the branch point P ₀₂ , and L ₀ is a branch point P _{01 to} P ₀₂ The line segment between them is shown. Since there is a line width w, when the thinning process is performed, each break point and two branch points are generated at the intersection of two straight lines as described above.

FIG. 7 is a diagram showing vector data of the graphic 2 shown in FIGS. 5 and 6. In FIG. 7, M _{0 to} M ₃₇ indicate addresses of a storage unit that stores vector data. The addresses M _{0 to} M ₇ are addresses for storing the vector data of the polygonal line L ₁ , and the head address M ₀ is the number of points (points P ₁ , P ₂ , P ₀₁ ) forming the polygonal line L ₁ (in this case, 3), the next address M ₁ indicates the line type of the polygonal line L ₁ . As the line types, the number “0” is a line without a branch point, the number “1” is a line whose start point is a branch point, the number “2” is a line whose end point is a branch point, and the number “3” is a start point and an end point. Both are lines that are branch points. Since the end point of the polygonal line L ₁ is a branch point, the line type is “2”. X ₁ , Y ₁ are the coordinates of the point P ₁ , X ₂ , Y ₂ are the coordinates of the point P ₂ ,
X ₀₁ and Y ₀₁ are coordinates of the point P ₀₁ . Hereinafter, the numbers attached to the points will be attached to the coordinates of the points. Similarly,
Address M ₈ ~M ₁₅ is vector data polygonal line L _3, the vector data in the address M ₁₆ ~M ₂₃ A line L _5, address M ₂₄ ~M _{3 1} vector data of the polygonal line L _7, the address M ₃₂ ~M ₃₇ is This is vector data of the line segment L ₀ .

When the thinning process is completed, a process of connecting the polygonal lines at the branch point is next performed. The conventional connection process will be described with reference to FIG. First, branch point P
_Pay attention to ₀₁ , and the polygonal lines L ₁ , L ₃ and line segment L ₀ related to this point
Is extracted and the angle of each line is calculated. In this case, the point P ₂ ,
Since the line segment between P ₀₁ and the line segment between points P ₄ and P ₀₁ are short, they are regarded as noise and ignored. Then, a combination in which the angle difference between the respective lines is a designated angle (180 degrees in this case) or a combination of lines closest to the designated angle is selected, and the selected two lines are connected. Similar processing is performed at the branch point P ₀₂ .

[0009]

In the conventional connection processing described above, when selecting a combination in which each line of the branch point has a designated angle, the processing must be stopped if each line is not at the designated angle. Even when selecting a line combination closest to the specified angle, the angle of each broken line including the line segment L ₀ is compared for each of the branch points P ₀₁ and P ₀₂ , so that an accurate connection is not always required. There was a problem that I could not. An example of such an incorrect connection will be described with reference to FIG.

FIG. 8 is a diagram showing an example of connection of the broken line shown in FIG. 8, the same parts as those shown in FIG. 6 are designated by the same reference numerals. The line segment that causes the noise is omitted. As is clear from FIG. 5, the connection of the polygonal lines shown in FIG. 6 is the connection of the polygonal line L ₁ , the line segment L ₀ and the polygonal line L ₇ , and the connection of the polygonal line L ₃ , the line segment L ₀ and the polygonal line L _5. Is an accurate connection. However, in the conventional connection processing, such an accurate connection cannot always be expected. For example, as shown in FIG. 8, a polygonal line L ₃ , a line segment L ₀ , and a polygonal line L ₇ are connected to form one line segment or a point. The straight line between P ₁ and P ₀₁ is another line segment L ₁₁ , and the straight line between points P ₅ and P ₀₂ is yet another line segment L ₁₁ .
_It becomes ₁₂ , and three line segments may occur.

When such an accurate connection is not made, for example, in the data processing, the point A in the figure 2 is
Even if an attempt is made to delete a line segment between ₁ and A ₂ , this line segment cannot be deleted because it is not in the data, and data processing becomes impossible. Furthermore, when the graphic to be processed is the electric circuit diagram of the printed circuit board, incorrect connection processing results in incorrect wiring on the electric circuit, and the printed circuit board becomes unusable.

Such an incorrect connection in the conventional connection process occurs not only in the graphic 2 but also in the graphic 3. That is, in the case of the figure 3, since the intersection C is the filled portion,
The end of each line segment is the peripheral edge of the filled portion. This will be described with reference to FIG. FIG. 9 is an enlarged view of an intersection C portion of the graphic 3 shown in FIG. As is clear from the figure, the intersection C
Are filled, that is, a set of pixels, and the end of each line segment is an outer pixel in the set of pixels. In this state, if the connection of the branch point is performed by the conventional connection processing means, the four straight lines passing through the intersection C are not formed, and an inaccurate connection as shown in FIG. 9 often occurs. However, this causes inconvenience in data processing.

The above-mentioned incorrect connection may be corrected by comparing the drawing displayed on the display surface with the original drawing based on the connection data after the connection processing is completed, but if there are many incorrect connection points. However, it takes a lot of trouble and time to correct, and in this case, the connection data is substantially unusable data.

An object of the present invention is to solve the above problems in the prior art and to provide a line figure branch point connecting method for an image input apparatus, which enables accurate connection.

[0015]

In order to achieve the above object, the present invention, in an image input device for reading a line graphic and storing it as vector data, extracts a branch point from the vector data and branches this branch point. The direction lines of a plurality of polygonal lines in contact with the points are calculated, and the selected direction line of these direction lines is captured when the direction line other than the direction line and the selected direction line is extended by a predetermined length. The direction line having the closest angle to the selected direction line with respect to the selected direction line is searched, and the searched direction line meets a predetermined condition with the selected direction line. When satisfied, the polygonal line to which the selected direction line belongs and the polygonal line to which the searched direction line belongs are connected.

Further, the present invention is characterized in that, in the above method, branch points are extracted from the vector data, and when a plurality of branch points exist within a predetermined range, these branch points are integrated into one branch point. ..

[0017]

The branch point is extracted from the stored vector data, and the direction lines of a plurality of broken lines in contact with this branch point are calculated. Regarding one selected direction line among the obtained direction lines, when the selected one direction line is extended by a predetermined length with the other direction line other than the concerned direction line, it is captured within a predetermined range in the extension process. Of the selected direction line, a direction line having an angle closest to the selected direction line is searched, and a predetermined condition is satisfied between the searched direction line and one selected direction line. When satisfied, the polygonal line to which the selected direction line belongs and the polygonal line to which the searched direction line belongs are connected. Similar processing is performed on polygonal lines other than the polygonal lines connected in this way.

If the number of line segments at the branch points is large, the branch points are extracted from the vector data, and when there are a plurality of branch points within a predetermined range, these branch points are integrated into one branch point. After that, the above processing is performed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a block diagram of an image input device for implementing a line figure branch point connecting method according to an embodiment of the present invention. Figure 1
Reference numeral 1 is a recording paper (drawing) on which figures 2 and 3 shown in FIG. 5 are drawn, 10 is a photoelectric conversion unit that scans the drawing 1 to pick up pixel data, and 11 is pixel data from the photoelectric conversion unit 10. Is an A / D converter for A / D conversion, and 12 is a control device composed of a computer. The control device 12 includes an input unit 121, a CPU 122, a ROM 123, and a RAM 12
4, an image data storage unit 125 that stores raster data,
A thinning processing unit 126 that performs thinning processing based on the data stored in the image data storage unit 125, and image tracking that obtains vector data by tracking the central pixel data obtained by the processing of the thinning processing unit 126. The processing unit 127, the coordinate sequence data storage unit 128 that stores the vector data obtained by the image tracking processing unit 127, and the output unit 129.
It is composed of.

Next, the operation of this embodiment will be described with reference to the flow chart shown in FIG. 2 and the diagram of the figure 2 shown in FIG. In the diagram shown in FIG. 3, the same parts as those shown in FIG. 6 are designated by the same reference numerals. First, the control device 12 integrates the branch points in the predetermined area based on the data stored in the coordinate sequence data storage unit 128 (step S ₁ shown in FIG. 2). This process is performed for a large number of branch points such as the figure 3 shown in FIG. 9, one branch point is taken out from the coordinate sequence data storage unit 128, and a predetermined distance from this branch point is obtained. The branch points within (for example, twice the predetermined line width) are searched and taken out, the coordinates of the center points of these branch points are obtained, and the coordinates of each branch point are replaced with the coordinates of the center point. For the calculation of the coordinates of the center point, a method of obtaining the center of gravity of each branch point or another appropriate method is used.

Once the branch points have been integrated, the controller 12 is then
Extracts polygonal lines in contact with one branch point from the coordinate sequence data storage unit 128 and calculates the direction lines of these polygonal lines (step S ₂ ). Here, an example of calculation of the direction line of the polygonal line L ₁ will be described with reference to FIG. First, a line segment between the starting point P ₁ and the break point P ₂ is extended, and a vertical line is extended from the branch point P ₀₁ to this line segment. The point of intersection is indicated by point D ₂ in FIG. A new point D ₁ is provided at this point D ₂ and an appropriate point on the line segment or an extension of the line segment. The line between the points D ₁ and D ₂ is the direction line of the polygonal line L ₁ . The resulting direction line is registered in the direction line stack, then Step S ₂ to whether the direction lines are calculated for all the broken line is determined (Step S _3), omnidirectional beam is calculated, Step S ₂ The processing of is executed.

Next, all the direction lines of the polygonal lines connected to one branch point are taken out from the direction line stack, and the set of the polygonal lines having the direction lines whose mutual angle difference is closest to 180 degrees is searched (step S). ₄ ). In FIG. 3, the direction lines D ₁ , D ₂
And the direction lines P ₀₁ and P ₀₂ (line segment L ₀ ) correspond to this, and both are selected.

Next, the controller 12 controls the virtual search window W.
Direction line D ₁ , using (for example, a size equal to the line width w),
D ₂ is extended in the direction of the branch point P ₀₂ by one search window W (step S ₅ ). Then, search the other direction lines present in the search window W (Step S _6), it is determined whether a direction line (Step S _7), since in this case no other direction line, the process procedure S ₈ Move to. In step S ₈ , it is determined whether the direction lines D ₁ and D ₂ have been extended by a predetermined length, that is, whether the search window W has moved a predetermined number of times. If the search window W has not moved a predetermined number of times, the process proceeds to step S 8. It returns to ₅ and the same search is repeated.

In the example shown in FIG. 3, since the polygonal lines L ₅ and L ₇ appear in the search window W in the third movement, it is determined in step S ₇ that there is a direction line. The control device 12 compares this directional line with the directional line of the line segment (L ₀ ) of the combination previously obtained in step S ₄ and determines the connection (step S ₉ ). This connection judgment is
Is the angle of the retrieved direction line even closer to 180 degrees,
This is performed by checking whether the distance between the branch point of the polygonal line to which the searched direction line belongs and the previous branch point is within a predetermined distance, or whether there is image background data between the branch points. In the example shown in FIG. 3, the direction line of the polygonal line L ₇ satisfies all these conditions.

When the processes of steps S ₅ to S ₈ are repeated and the extension of the direction lines D ₁ and D ₂ by the search window W by the predetermined length is completed, the obtained combination of the direction lines most meets the condition. It will be a combination. Accordingly, the control unit 12 performs the connection of the polygonal lines each direction lines combined belongs (Step S _10). In the case shown in FIG. 3, the polygonal line L ₁ and the polygonal line L ₇ are connected via the line segment L ₀ .

Next, the control device 12 judges whether or not the processing has been completed for all the data stored in the coordinate sequence data storage unit 128 (step S ₁₁ ), and if the processing has not been completed, the procedure S ₄ again. The following process is executed, and by this process,
In the example shown in FIG. 3, the polygonal line L ₃ and the polygonal line L ₅ are connected.

The data obtained by such a connection method (data for the example shown in FIG. 3) is shown in FIG. In FIG. 4, the data at addresses M _{0 to} M ₁₃ are the start point P ₁ , the break point P ₂ , the branch point P ₀₁ , the branch point P ₀₂ , the break point P ₈ , and the start point P.
It is the data of one line segment connecting ₇ and the address M ₁₄
The data from M ₂₇ to M ₂₇ is one line segment connecting the starting point P ₃ , the breaking point P ₄ , the branching point P ₀₁ , the branching point P ₀₂ , the breaking point P ₆ , and the starting point P ₅ . The former line segment is the points A ₁ and A _{2 of the} figure 2 shown in FIG.
It is obvious that the latter corresponds to the line segment between the points B ₁ and B ₂ . This data is stored as coordinate sequence data.

Finally, the controller 12 detects the short broken line and deletes it (step S ₁₂ ). Here, the short polygonal line means that the total length of the line segments forming the polygonal line is a predetermined length or less, and one side of a rectangle indicated by the maximum and minimum coordinates of X and Y of the line segments constituting the polygonal line has a predetermined length. It means one that meets the following conditions. By this process, the line segment between each line segment break point and the branch point shown in FIG. 3 is deleted.

As described above, in this embodiment, the branch points are integrated, the direction line of each polygonal line at the branch point is obtained, and this is extended to search for a polygonal line with better conditions. By comparison, the connection at the branch point can be made much more accurately.

[0030]

As described above, in the present invention, when a plurality of branch points occur, the branch points are integrated, the direction line of each polygonal line at the branch point is obtained, and this direction line is extended to satisfy the condition. Since a good broken line is searched for, the connection at the branch point can be made accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of an image input device that implements a line graphic branch point connection method according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the device shown in FIG.

FIG. 3 is a diagram explaining the operation of the apparatus shown in FIG.

FIG. 4 is a diagram showing data stored in a storage unit.

FIG. 5 is a diagram showing a figure drawn on a recording sheet.

FIG. 6 is an enlarged view of the figure shown in FIG.

FIG. 7 is a diagram showing data stored in a storage unit.

FIG. 8 is a diagrammatic view of the figure shown in FIG.

FIG. 9 is a diagrammatic view of the figure shown in FIG.

[Explanation of symbols]

 1 Drawing 10 Photoelectric Conversion Unit 12 Control Device 122 CPU 125 Image Data Storage Unit 126 Thinning Processing Unit 127 Image Tracking Processing Unit 128 Coordinate Sequence Data Storage Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Nishijima 2100 Kamiimaizumi, Ebina, Kanagawa Prefecture Hitachi Seiko Co., Ltd.

Claims (3)

[Claims] 1. An image input device which reads a line figure and stores it as vector data, extracts a branch point from the vector data, calculates direction lines of a plurality of polygonal lines in contact with the branch point, and draws these direction lines. Of the selected direction line among the other direction lines, and among the direction lines that are captured when the selected direction line is extended by a predetermined length, a predetermined direction line with respect to the selected direction line. The direction line having an angle closest to the angle is searched, and when the searched direction line meets a predetermined condition with the selected direction line, the polygonal line to which the selected direction line belongs and the search. And a polygonal line to which the generated direction line belongs is connected. 2. An image input device which reads a line figure and stores it as vector data, extracts branch points from the vector data, and when there are a plurality of branch points within a predetermined range, these branch points form one branch. The direction lines of a plurality of polygonal lines contacting this branch point are integrated with each other, and the selected direction line among these direction lines is a predetermined direction line other than the direction line and the selected direction line. Of the direction lines captured when the length is extended, a direction line having an angle closest to a predetermined angle with respect to the selected direction line is searched, and the searched direction line is the selected direction line. When a predetermined condition is satisfied between the line patterns, the polygonal line to which the selected direction line belongs and the polygonal line to which the searched direction line belongs are connected to each other. .. 3. The predetermined condition according to claim 1 or 2, wherein when the polygonal line to which the adopted direction line belongs is a polygonal line extending from a branch point other than the branch point, a distance between the branch points is A method for connecting a line figure branch point of an image input device, wherein the background data of the image is shorter than a predetermined length.