JP2797660B2 - Pixel correction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image enlargement process, and particularly, performs double enlargement in horizontal and vertical directions (hereinafter referred to as “horizontal and vertical double enlargement process”). Pixel correction at the time.

[Conventional technology]

Conventionally, in the horizontal and vertical double enlargement processing of an image, as shown in FIG. 1 (B) with respect to FIG. 1 (A), for each pixel of the original image data 1, double the bit of the pixel is assigned. The allocation only doubles the data in the horizontal direction, and then writes the data on two consecutive lines to convert the data into enlarged image data 2 that has been doubled in the horizontal and vertical directions.

[Problems to be solved by the invention]

In the above-described conventional double enlargement processing in the horizontal and vertical directions, by allocating twice the number of bits to each pixel of the original image data in the horizontal direction, and to successively extend the data in the vertical direction by two times. Since the processing is realized by writing to the line, there is a drawback that the enlarged image data obtained by performing the enlargement processing twice in the horizontal and vertical directions is angular and coarse.

Therefore, an object of the present invention is to provide a method for obtaining enlarged image data that is not coarse.

[Means for solving the problem]

In the present invention, in the image enlarging process of a binary image, binary image data stored in advance is enlarged twice in the horizontal and vertical directions, and is then enlarged twice in the horizontal and vertical directions. Focusing on one of the two consecutive horizontal lines, the left and right pixels in the horizontal direction of the black pixel in the image data are set to black, and the operation of doing nothing to the white pixel is repeatedly performed to increase the number of black pixels. By creating value image data and further focusing on three consecutive lines in which the number of black pixels is increased in the binary image data in which the number of black pixels is increased, the binary image data in which the number of black pixels is increased is corrected.
Obtain a smoothed image that is enlarged twice in the horizontal and vertical directions.

〔Example〕

Referring to FIG. 1, in one embodiment of the present invention, original pixel data 1 having three horizontal lines 11 to 13 as shown in FIG.
Double enlargement processing is performed to obtain 2 × 2 enlarged image data 2 as shown in FIG. 1 (B). Here, the horizontal line is expanded into six lines 111, 112, 121, 122, 131 and 132. Next, two consecutive horizontal lines 111 of the 2 × 2 enlarged image data 2
And 112, 121 and 122, and 131 and 132, respectively, and focuses on one of the lines (in this example, the lower line) 112,
For the pixels 122 and 132, a process of increasing only the black pixels by setting the white pixels on the left and right of the black pixels (group) as black pixels is performed (the white pixels are not increased). As shown in FIG. Pixel-enhanced image data 3 is obtained. Focusing on the three lines 212, 222, and 232 in which the number of black pixels has increased due to this processing, one of the lines is compared with the line above or below (or both), and is determined as a black pixel only in the case of a combination of black pixels and black pixels. In the case of another combination, pixel data correction of white pixels is performed. In this embodiment, the black pixel increase line 212 shown in FIG.
1D, a black pixel is left as a correction line 312 as shown in FIG. 1 (D). Similarly, the black pixel increase line 222 is compared with the lower same line 232 to obtain a correction line 322. Create Since the line below the black pixel increase line 232 does not exist (white), the black pixel becomes zero.
As a result of such correction, the corrected image data 4 of FIG. 1 (D) is obtained.

The image enlargement correction processing as described above can be realized using known hardware. For example, as shown in FIG. 2, a hardware 21 including a data compression / decompression controller is used to create an image data file that is enlarged twice in the horizontal and vertical directions from the original image data 1 and the created data is The left and right pixels of the black pixel are set as black pixels for any one of the two lines continuous with the above. Focusing on the three consecutive lines in which the number of black pixels has increased, mask processing is performed on the upper and lower lines with the second line of the three consecutive lines as the center, and a black pixel is determined only when the combination is a black pixel or a black pixel. In other cases, line correction for white pixels is performed. When the present invention is implemented by software, 21 in FIG. 2 is used as a CPU. When a program written by the algorithm of the present invention is loaded,
Are read one after another, and the data is converted according to the algorithm to convert the image data into two-fold enlarged image data in the horizontal and vertical directions. Continuous 2 based on the created data
For any one of the lines, the left and right pixels of the black pixel are set as black pixels. Focusing on the three consecutive lines in which the number of black pixels has increased, mask processing is performed on the upper and lower lines with the second line of the three consecutive lines as the center, and a black pixel is determined only when the combination is a black pixel or a black pixel. In other cases, line correction for white pixels is performed.

〔The invention's effect〕

As described above, the use of the pixel correction method of the present invention makes it possible to provide smoother image data for image data that is enlarged twice in the horizontal and vertical directions.

[Brief description of the drawings]

1A to 1D show image data at each stage in image processing according to an embodiment of the present invention, and FIG. 2 shows an example of a means for realizing the image data. The numbers indicated in the figure are as follows. 1 ... original image data, 2 ... 2 x 2 enlarged image data, 11
2, 122, 132 ... lines to which black pixels are added, 3 ... image data to which black pixels are added, 212, 222, 232 ... lines to be corrected, 4 ... corrected image data, 21 ... hardware,
22 ... The system bus.

Claims (1)

(57) [Claims] 1. A process in which binary image data stored in advance is enlarged twice in the horizontal and vertical directions, respectively, and two consecutive image data in the vertical direction of the binary image data enlarged twice in the horizontal and vertical directions are processed. The binary image data in which the number of black pixels is increased by performing operations of setting the left and right pixels in the horizontal direction of the black pixels of the image data to black and performing no operation for white pixels for one of the horizontal lines A pixel correction method comprising correcting the binary image data having the increased black pixels by focusing on three consecutive horizontal lines having the increased black pixels of the binary image data having the increased black pixels.