JPH0594529A - Method for expanding graphic - Google Patents

Abstract

PURPOSE:To obtain an expansion method capable of expanding a graphic without generating a topology change. CONSTITUTION:The near-by information of a background picture element adjacent to a boundary picture element on a binary image is extracted, the near-by information of respective background picture elements is registered in a memory, and when plural discontinued graphic picture elements exist in the neary-by information, a mask image is formed by the corresponding background picture elements and the mask image is used as an inhibition area to expand the binary image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic expansion method,
In particular, it relates to an expansion method capable of expanding a graphic while preserving the topology of the graphic.

[0002]

2. Description of the Related Art Graphic expansion is widely known as a process effective in noise removal for removing minute irregularities on the periphery of a graphic in combination with contraction processing. However, as a result of expansion, fusion of adjacent figures may occur and the topology may change. Image fusion is a beneficial effect depending on the subsequent processing, but it is not preferable when trying to obtain an expanded figure while maintaining the topology, that is, the number of groups and the number of holes.

[0003]

SUMMARY OF THE INVENTION The present invention was devised to solve such conventional problems, and an object thereof is to provide an expansion method capable of expanding a figure without causing a topology change. To do.

[0004]

A graphic expansion method according to the present invention obtains neighborhood information of a background pixel adjacent to a graphic boundary, and generates a mask image giving an expansion prohibited area based on the neighborhood information.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of a graphic expansion method according to the present invention will be described with reference to the drawings. FIG. 1 shows a flow chart of the embodiment, in which an image to be processed is taken in by an input means such as a video camera (step 1-
1) Binarized (step 1-2) and once registered in the memory (step 1-3). For this binary image,
Neighborhood information is obtained for each convolution of a predetermined size (step 1-4). The neighborhood information mentioned here is a concept similar to the number of connections and is a numerical value indicating how many groups the surrounding pixels can be divided into. Regarding the number of connections, it is premised that the central pixel is a graphic pixel, but here it is premised that the central pixel is a background pixel.

When a plurality of groups of graphic pixels are present around the central pixel and the background pixel at the center is converted into a graphical pixel as a result of expansion, the central pixel connects the surrounding graphics and changes the topology. Become. To prevent this topology change, the central pixel is the background pixel,
If there are a plurality of groups of graphic pixels in the surroundings, the central pixel is excluded from the expansion target. The above judgment is
If the exclusion conditions are met in steps 1-5 to 1-6, a density indicating prohibition of expansion is written on the mask plane (step 1-7). When the density of the background pixel is "0" and the density of the graphic pixel is "1", another density, for example, "255" is adopted as the density indicating expansion prohibition. When the above process is completed for the entire one image (step 1-8), the expansion process is performed on the original image while referring to the generated mask plane (step 1).
-9).

FIG. 2 shows an example in which the central pixel should not be the target of expansion, and FIG. 3 shows an example of not being the target of expansion. Figure 2
In, pixels A and F are graphic pixels, and these are separated from each other. On the other hand, in FIG. 3, adjacent pixels A and B are graphic pixels.

In the above process, when a concave portion is present in one group of graphics (FIG. 4), in the convolution C1 for looking at the middle portion of the concave portion, a plurality of groups of graphic pixels are present in the surrounding pixels. However, in the convolution C2 that catches the bottom of the recess, it is found that the surrounding pixels are one group, and if the expansion is advanced from here, the recess can be finally filled. That is, it can be understood that the existence of pseudo multiple groups can be eliminated by repeating expansion.

[0009]

As described above, according to the present invention, it is possible to expand a graphic without changing the topology of the graphic image.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining an embodiment of the present invention.

FIG. 2 is an example of discontinuous graphic pixels that are not subjected to expansion processing.

FIG. 3 is an example of continuous graphic pixels to which expansion processing is applied.

FIG. 4 is a diagram showing an example in which a figure has a recess.

Claims (1)

[Claims] 1. The neighborhood information of a background pixel adjacent to a boundary pixel of a binary image is extracted, the neighborhood information of each background pixel is registered in a memory, and the neighborhood information includes a plurality of discontinuous graphic pixels. Sometimes, a mask image is generated by the corresponding background pixel, and the binary image is expanded using the mask image as a prohibited area.