JPS62208178A - Device for connecting cut line - Google Patents

Abstract

PURPOSE:To prevent a part other than a cut line from being erased and to effectively connect the cut line part by discriminating connectivity from an end point by using the values of respective picture elements and terminal point information and generating connecting segment between two points decided beeing connected. CONSTITUTION:Binary input data setting up '0' and '1' in a white picture element and a black picture element respectively are held in an image storing part 1 of a cut line connecting device and the input image is thinned by a thinning part 2. At that processing, the label of a picture element to be erased is set up to '1' not to '0'. On the other hand, positional coordinates and directivity are registered in an end point information storing part 3 every end point out of end points (opened ends) of the thinned result and a connection flag for two end points is disconnected. after the end of thinning, the continuity of the end points in the storage part 3 is checked by a continuity deciding part 4 and a pair of two end points separated from the center by a fixed threshold or more is found out. In case the continuity exists, a continuous segment is generated from a continuous segment generating part 5. Thus, the part other than a cut line is prevented from being erased and the cut line part is effectively connected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is intended to prevent variations in the characteristics of the scanner, etc. and defects in the input image itself when inputting line images to various image processing devices, general-purpose computers, etc. using various scanners, etc. The present invention relates to a line break connecting device for connecting line breaks caused by uniformity and obtaining a good input image.

BACKGROUND OF THE INVENTION In recent years, various image processing technologies have been progressing due to strong demands from industry and the like. Connecting line breaks is considered to be an important preprocessing technique for obtaining good input images in various types of image processing.

Hereinafter, an example of the above-mentioned conventional line breakage connection device will be described with reference to the drawings.

FIG. 3 shows the configuration of a conventional line breakage connection device. In FIG. 3, 11 is a black pixel expansion section, and 12 is a black pixel contraction section.

The operation of the line break connection device having the above configuration will be described below. FIG. 4 shows an example of a line image input to the line break connecting device, and FIG. 5 a shows the vicinity of the line break. For the sake of simplicity, a square grid image in which 8 pixels (black pixels) representing a line figure are connected will be taken as an example. In FIG. 5, black circles B are black pixels, and white circles W are pixels (white pixels) representing the background. The objects to be connected are black pixels.

The black pixel expansion unit 11 shown in FIG. 3 expands the black pixel area of the input image. - times of dilation, change all white pixels adjacent to black pixels in the input image to black pixels. The result of performing one dilation on the input image of FIG. 5a is shown in FIG. Furthermore, by performing another expansion using this figure 5 as input, the result shown in figure 5C is obtained. at this point
Line breaks in the input image are connected.

The black pixel contraction section 12 shown in FIG. 3 converts black pixels into white pixels, contrary to the black pixel expansion section 11. However, in this case, instead of changing all the black pixels adjacent to the white pixels to white pixels, only the pixels that do not divide the black pixel area are changed.

The number of black pixel expansions M1 and the number of black pixel contractions M2 are determined as follows. To connect the target line breaks,
For the shortest distance N between line breaks (3 in Fig. 5), it must be M, 〉--N. Furthermore, M2 varies depending on the target image. For example, if you want to obtain the same line width as the original image, M2=M.

It's fine if you do this. In addition, in order to obtain a thinned image, M2
≧M1. FIG. 6d shows the result of performing black pixel contraction twice using FIG. 5C as an input image. At this time, M2:M.

(For example, "Digital Image Processing" translated by Makoto Nagao, Kindai Kagakusha, pages 376-384).

Problems to be Solved by the Invention However, in the above configuration, the black pixel area is expanded regardless of the mutual arrangement of the black pixel areas, so as shown in FIG. In some cases, areas that should be connected are connected, or as shown in Figure 6, meaningful white pixel areas contained within black pixel areas (
In addition, even if black pixel areas are contracted in these images, they cannot be separated or a hole area can be generated.

In view of the above-mentioned problems, the present invention extracts only the broken line parts in the input image and connects those parts, thereby eliminating undesirable connections in parts other than the broken lines and erroneous effects such as deletion of hole areas. , provides a good line break connection device.

Means for Solving the Problems In order to solve the above problems, the line break connection device of the present invention holds image data digitized in units of pixels,
There is an image storage unit that stores the value (label) of each pixel that will be rewritten by subsequent processing, a thinning unit that extracts the skeleton of the line drawing part while changing the value of the original image, and a thinning unit that extracts the skeleton of the line drawing part while changing the value of the original image. An endpoint information storage unit that stores information; a connectivity determination unit that determines connectivity from the endpoints using the label and endpoint information; and a connectivity determination unit that determines connectivity between two points that are determined to have connectivity by the connectivity determination unit. and a connecting line segment generating section that generates connecting line segments.

Operation With the above-described configuration, the line break connection device of the present invention performs line thinning on the input image data held in the image storage unit while labeling erased pixels during line thinning. At least one end of the cut portion becomes an endpoint, and information regarding this endpoint is stored in the endpoint information storage unit, and the connectivity determination unit determines whether the endpoints are connected to each other or the endpoint and a point in the black pixel area on its extension. It is determined whether the separation is due to a line break, and only for the part determined to be a line break, a line segment that connects two points is generated in the connecting line segment generation section, and the white pixels on the line segment are generated. This is to rewrite to black pixels.

EXAMPLE Hereinafter, a line breakage connecting device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a line breakage connection device in an embodiment of the present invention. In FIG. 1, 1 is an image storage section, 2 is a thinning section, 3 is an end point information storage section, 4 is a connectivity determination section, and 6 is a connecting line segment generation section.

The operation of the wire breakage connection device configured as described above will be described below.

First, the data input to the image storage unit 1 is 2
It is a valued image, and has a pixel value (label) of 1e □ I+ for a white pixel and Jl+ for a black pixel.

The input image is thinned by a thinning section 2. Here, the label of the pixel to be erased is not set to 1(-111
I'll leave it as that. Furthermore, for the end points (open ends) that appear as a result of line thinning, the position coordinates and directionality of each end point are registered in the end point information storage unit 3, and the connection flag is set to "unconnected." Figures 2a and 2b show examples of labels and endpoint information lists after thinning.

After the thinning is completed, the connectivity determination unit 4 first examines the connectivity between the end points. Find a pair of two endpoints whose distance is less than a certain threshold from among the endpoints stored in the endpoint information storage unit 3, and check whether there are any problems with the position and directionality of the two endpoints (the two endpoints are connected by a line segment). Check to see if there are any sharp corners, etc.). Look at the labels of each pixel on the connected line segment for a set of two endpoints that have no problems. In other words, the pixel with the label l I I+ was originally a black pixel, whereas the pixel with the label '0'' was originally a white pixel, so the 10'' on the connecting line segment
It is determined that a set in which the number of pixels, that is, the distance before thinning is equal to or less than a certain value, has connectivity. Then, in the end point information list of the end point information storage section, the connection flag of the two end points is rewritten to ``Connected''.Furthermore, the connection line segment generation section 3 changes the label of each pixel on the connected component that connects the two end points to `'. Rewrite it to 1″.

Figure 2C shows the label after connection.

After the end points are connected, the connection flag in the end point information list is set to ``until'' in order to connect a line break where the end points occur only on one side, such as the unconnected part shown by arrow G in Figure 7. The following processing is performed for the endpoints that remain connected.

From the directionality of each endpoint, check whether there is a pixel with the label '1' within a certain angle and within a certain distance. If so, consider the pixel with the '°1' label as the endpoint. Similarly to the connection between end points, connectivity is determined from the labels of pixels on the connected line segment, and a connected line segment is generated.

As described above, according to this embodiment, the skeleton is extracted while changing the label of each pixel stored in the image storage unit 1 in the thinning unit 2, and the obtained endpoint information is stored in the endpoint information storage unit 3. After storing, the connectivity determining unit 4 determines the connectivity from the end points using the label and end point information, and the connecting line segment generating unit 6 generates connecting line segments for broken line parts that have connectivity. It is possible to connect only the broken parts.

Note that in this example, only the line breaks were connected, but in order to obtain an image with the same thickness as the original line drawing, +4. I
It is sufficient to rewrite the pixels with the + label to the label ''1'.

Furthermore, in order to obtain a complete thinned image, the image obtained in this embodiment may be input to the thinning section 2 again.

Effects of the Invention As described above, the present invention provides an image memory that holds target image data digitized in units of pixels including line breaks, and stores the value (label) of each pixel that is rewritten by subsequent processing. a line thinning unit that extracts the skeleton of the line drawing part while changing the label of the original image; an end point information storage unit that stores information on the end points extracted by the line thinning unit; By providing a connectivity determination unit that determines connectivity from an end point, and a connection line segment generation device that generates a connection line segment between two points determined to have connectivity by the connectivity determination unit, the line No errors such as undesired connections in non-cut areas or erasure of hole areas.
A good line break connection device can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a line break connection device in an embodiment of the present invention, FIG. 2 is a block diagram showing an example of label and end point information in an embodiment of the present invention, and FIG. 3 is a conventional line break connection device. FIG. 4 is a configuration diagram showing an example of an input line drawing including a line break portion, FIG. 5 is a state diagram showing changes in pixel values in an example of a conventional line break connection device, and FIG. FIG. 7 is a state diagram illustrating undesirable malfunctions caused by the conventional line break connection device. FIG. 7 is a state diagram illustrating that end points are generated when a line break image is thinned. 1... Image storage unit, 2... Line thinning unit,
3...End point information storage unit, 4...Connectivity determination unit, 6...Connection line segment generation unit. Name of agent: Patent attorney Toshio Nakao and one other IJ
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Claims (1)

[Claims] An image storage unit that holds digitized image data pixel by pixel and stores the value of each pixel that is rewritten by subsequent processing, and extracts the skeleton of the line drawing part while changing the value of each pixel of the original image. a line thinning unit; an end point information storage unit that stores information on the end points extracted by the line thinning unit; a connectivity determining unit that determines connectivity from the end points using the value of each pixel and the end point information; A line break connection device comprising: a connection line segment generation unit that generates a connection line segment between two points determined to have connectivity by a connectivity determination unit.