JPH0594527A - Method for reducing graphic - Google Patents

Abstract

PURPOSE:To obtain a graphic reducing method capable of preventing the genera tion of an erosion between graphics even at the time of applying reduction processing to plural graphics having respectively different brightness values in a many-valued image. CONSTITUTION:A center picture element in a prescribed convolution on a labeled image is a graphic picture element, the minimum brightness value in the convolution is applied to the center picture element in a condition that the convolution includes a background picture element, and in other conditions, the brightness values of picture elements in the image are adopted as they are.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic contraction method,
In particular, it relates to a graphic shrinking method for shrinking a graphic in a multivalued image.

[0002]

2. Description of the Related Art Conventionally, performing a contraction process on a graphic is an effective method for removing noise at the edge portion of the graphic together with the expansion process. However, when a graphic in a multi-valued image is subjected to contraction processing, a graphic having a smaller brightness value between adjacent graphics having different brightness values may erode a graphic having a high brightness value.

[0003]

The present invention was devised in order to solve the above-mentioned conventional problems. Even if a graphic having different brightness values in a multi-valued image is subjected to contraction processing, the erosion between the graphics is eroded. It is an object of the present invention to provide a method of shrinking a figure that does not have a pattern.

[0004]

A graphic contraction method according to the present invention performs an inter-image calculation between a labeled image and an image in which a specific luminance value is given to a graphic pixel.

[0005]

Even if a plurality of figures having different brightness values are subjected to contraction processing, the erosion between the figures can be avoided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the graphic contraction method according to the present invention will now be described with reference to the drawings. FIG. 1 shows a flow chart of the embodiment, in which an image to be processed is captured by an input means such as a video camera (step 1-
1), the captured image is labeled as shown in FIG. 2 (step 1-2). Here, luminance values other than the specific luminance value described later, for example, the background luminance value “0”, the figure A luminance value “1”, and the figure B luminance value “2” are once registered in the memory (step 1 -3).

The image subjected to the labeling process is taken in every predetermined convolution (step 1-4), and the contraction process is performed under the following conditions. That is, only when the central pixel is a graphic pixel and the background pixel exists in the convolution (step 1-5), the minimum luminance value of the pixel in the convolution (the luminance value of the background pixel is “0”) is present in the central pixel. ) Is given (step 1-6). If the contraction process is performed only under such a condition, the convolution as shown in FIG. 5, that is, if the background pixel (the brightness value “0”) does not exist, it is excluded from the contraction process. The small figure A does not erode the figure B having a large luminance value. This process is performed for each image up to the end (step 1-7). It should be noted that this process is performed a required number of times based on the figure or the like.

After this contraction processing, as shown in FIG. 3, all graphic pixels (luminance values "1" and "2") are converted into a specific luminance value, here 255 (step 1-8), The image is registered in the memory (step 1-9). Then, the image registered in step 1-3 and the image registered in step 1-9 are subjected to MIN calculation (step 1-10).
Here, when both images are compared and the minimum luminance value is taken, FIG. 4 is obtained.

As is apparent from FIG. 4, a predetermined contraction process is performed on the part adjacent to the background pixel, that is, the edge part, but the contraction process is not performed on the other parts, so-called erosion is prevented. ing.

[0010]

As described above, according to the present invention, even if a graphic contraction process is performed, no erosion occurs between adjacent graphics having different luminance values, and a graphic subjected to noise processing can be extracted. .

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram in which labeling processing is performed.

FIG. 3 is a conceptual diagram in which a specific luminance value is given to a graphic pixel.

FIG. 4 is a conceptual diagram in which minimum luminance values of the images of FIGS. 2 and 3 are taken.

FIG. 5 is a conceptual diagram of convolution including adjacent graphics having different brightness values.

Claims (1)

[Claims] 1. The minimum luminance value in the convolution is given to the central pixel provided that the central pixel in the predetermined convolution of the labeled image is a graphic pixel and the background pixel is included in the convolution. Under the other conditions, the brightness value of the pixel of the image is adopted as it is, and the graphic contraction method is characterized.