JP3452202B2 - Image processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus which divides each pixel of binary image data into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data.

[0002]

2. Description of the Related Art For example, the image reading resolution of a group 3 facsimile apparatus is a standard resolution of 8 (dots / millimeters) in the main scanning direction and 3.75 (lines / millimeters) in the sub-scanning direction, and 8 (dots) in the main scanning direction. Dot / mm) and 7.7 (line / mm) in the sub-scanning direction
Fine resolution, main scanning direction is 8 (dots / millimeters) and sub-scanning direction is 15.4 (lines / millimeters) semi-super fine resolution, and main scanning direction is 16 (dots / millimeters) and sub-scanning direction is 1
Four types of super fine resolution of 5.4 (lines / millimeter) are used.

Here, there are two standard resolutions and fine resolutions.
The types are specified in CCITT's recommendations as the device functions of the group 3 facsimile machine, but the two types of semi-super fine resolution and super fine resolution are original to the manufacturer not specified in the recommendation of the group 3 facsimile machine. Optional resolution.

Therefore, the group 3 facsimile machines supplied to the market are provided with only two kinds of standard resolution of standard function and fine resolution, and in addition to standard resolution and fine resolution of standard function. ,
There are those with optional features of semi-super fine resolution, or even those with super fine resolution.

Group 3 having a device function of semi-super fine resolution or super fine resolution
When a facsimile machine receives an image of a lower resolution, that is, a standard resolution or a fine resolution, the resolution of the received image is the largest resolution that can be recorded and output by the terminal itself, for example, a semi-super fine resolution or a super fine resolution. The image density of the received image can be improved by converting the pixel density of the image into the image density of the image and outputting the image with the converted pixel density at the recording density of the semi-super fine resolution or the super fine resolution. .

In the pixel density conversion processing for forming recording data (image data) having a higher resolution, basically, one pixel of the original image data (hereinafter referred to as a pixel of interest) is converted into the original image data. Is divided into a number corresponding to the ratio of the resolution of the recording data to the resolution of the recording data, and the color of the divided pixel (hereinafter referred to as divided pixel) is set to the same value as the color of the pixel of interest.

Further, so-called smoothing processing for smoothing the jaggedness of an image such as diagonal lines is performed,
The image quality of the recorded image is improved.

[0008]

However, such a conventional method has the following disadvantages.

That is, in the smoothing process associated with the pixel density conversion process, the image quality of a diagonal image with a constant angle can be improved to some extent, but the image with a diagonal line at other angles, the image of the uneven portion, or There is a disadvantage that the quality of the curved image cannot be improved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image processing apparatus capable of further improving the image quality of an image after pixel density conversion.

Incidentally, JP-A-59-163948, JP-A-3-186059, and JP-A-61-2378.
Although Japanese Patent Laid-Open No. 5 discloses a smoothing process for binary image data, the invention described in Japanese Patent Laid-Open No. 163948/1984 relates to a smoothing technique for enlarging a dot character, and therefore a diagonal line Also, the desired result cannot be obtained even if it is applied to smoothing of any image such as unevenness or a curve. Further, the invention described in Japanese Patent Laid-Open No. 3-186059 is limited to the case where the size of the read data pixel in the main scanning direction is twice as large as the size of the print data pixel. It wasn't intended. Further, in the invention described in Japanese Patent Laid-Open No. 61-203785, a logical window having a fixed size is provided, and the color of each divided pixel of the target pixel subdivided therein is determined by calculation. Since it is different from the method of determining the color of each divided pixel in the target pixel according to the state of the surrounding pixel adjacent to the target pixel as in the present invention, there is a problem that the smoothing accuracy of the boundary line throughout the entire image cannot be improved. There is a point.

[0012]

SUMMARY OF THE INVENTION The present invention provides an image processing method in which each pixel of binary image data is divided into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data. A plurality of divided pixels obtained by dividing the target pixel according to the black-and-white pattern of the center adjacent pixel adjacent to the target pixel and a part of the black-and-white pattern of the surrounding adjacent pixels adjacent to the outer region of the center adjacent pixel. Is set so as to smooth the image of the oblique line or the uneven portion in a desired manner, and in the setting, the color of the divided pixel is opposite to the color of the pixel of interest in accordance with the black-and-white pattern of the central adjacent pixel. It is characterized in that whether or not the color is set is determined, and the colors of the plurality of divided pixels are set according to a part of the black and white pattern of the neighboring pixels.

Further, in the image processing method of dividing each pixel of the binary image data into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data, the surrounding area adjacent to the target pixel to be processed Depending on the black-and-white pattern of the pixels, the colors of the plurality of divided pixels obtained by dividing the target pixel are set so as to smooth the image of the oblique line or the uneven portion in a desired mode, and in the setting, The number of divided pixels to be set to a color opposite to the color of the pixel of interest is set according to the color of the pixel and the black-and-white pattern of the surrounding pixels.

Further, in the image processing method in which each pixel of the binary image data is divided into a plurality of pieces to form image data of pixels smaller than the pixels of the original image data, the target pixel to be processed and the target pixel According to the black-and-white pattern of a plurality of surrounding pixels adjacent to, the color of the plurality of divided pixels obtained by dividing the pixel of interest is set so as to smooth the image of the diagonal line or the uneven portion in a desired mode, In this setting, the number of divided pixels to be set to the color opposite to the color of the target pixel is set according to the protruding direction of the edge portion where the target pixel is located, the color of the target pixel, and the black-and-white pattern of the surrounding pixels. It is characterized by having done.

[0015]

In addition, in the image processing method in which each pixel of the binary image data is divided into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data, peripheral pixels adjacent to the target pixel to be processed. According to the black and white pattern, the color of the plurality of divided pixels obtained by dividing the pixel of interest is set so as to smooth the image of the oblique line or the uneven portion in a desired mode, and in the setting, the black and white pattern is set. To
It is characterized in that it is changed according to the image type of the image data to be processed.

In addition, in the image processing method, each pixel of the binary image data having different pixel size is divided into a plurality of pixels to form image data of a single size pixel smaller than the pixel of the original image data. According to the black and white pattern of the surrounding pixels adjacent to the target pixel, the color of the plurality of divided pixels obtained by dividing the target pixel is set so as to smooth the image of the diagonal line or the uneven portion in a desired manner. At the same time, in the setting, the black-and-white pattern is changed according to the pixel size of the input image to be processed.

Further, the mixed binary image data in which the read binary image data obtained by reading by the image input means and the generated binary image data generated by the character generator are mixed, the binary image data of smaller pixels is obtained. In the image processing method of converting to, in accordance with the black-and-white pattern of surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black-and-white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary It is characterized in that the inversion processing is not performed for the image line in the main scanning direction including the image data.

Further, the mixed binary image data in which the read binary image data obtained by reading by the image input means and the generated binary image data generated by the character generator are mixed, the binary image data of smaller pixels In the image processing method of converting to, in accordance with the black-and-white pattern of surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black-and-white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary It is characterized in that the inversion processing is not performed on the pixel of interest forming the image data.

Further, the mixed binary image data in which the read binary image data obtained by reading by the image input means and the generated binary image data generated by the character generator are mixed, the binary image data of smaller pixels In the image processing method of converting to, in accordance with the black-and-white pattern of surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black-and-white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary The image area of the image data is characterized in that the inversion processing is not performed.

[0021]

Therefore, according to the present invention, the divided pixels are set to an appropriate black-and-white pattern in the image portion of the shaded portion and the uneven portion at an arbitrary angle, and the image quality of the image after the pixel density conversion becomes good.

[0022]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

In the following embodiment, the main scanning direction is 8 (dots / millimeter) and the sub scanning direction is 3.75.
Image resolution (line / millimeter) is standard resolution,
Image resolution of 8 (dots / mm) in the main scanning direction and 7.7 (lines / mm) in the sub-scanning direction is fine resolution, and 8 (dots / mm) in the main scanning direction.
The image resolution of 15.4 (lines / mm) in the sub-scanning direction is semi-super fine resolution, and the image resolution of 16 (dots / mm) in the main scanning direction and 15.4 (lines / mm) in the sub-scanning direction. Is called super fine resolution.

1A and 1B show a pixel matrix applied to the image processing method according to the embodiment of the present invention. In this embodiment, a fine resolution image is pixel density converted to a super fine resolution.

That is, the target pixel of the fine resolution which is the target of the pixel density conversion processing is X, and the target pixel X is the divided pixels x0, x1, x2 of the super fine resolution.
When divided into x3, the center adjacent pixels A, B, C, D, E, F, G, H adjacent to the target pixel X and the center adjacent pixels A, B, C, D, E, F, Surrounding neighboring pixels a, b, c, d, e, f, g, h, i adjacent to G and H,
divided pixel x by referring to j, k, l, m, n, o, p
Set the colors of 0, x1, x2, and x3.

For example, as shown in FIG. 2A, the image of the area of the central adjacent pixels A, B, C, D, E, F, G, H and the target pixel X changes from the lower left to the upper right. In the case of a pattern having, the color of the surrounding adjacent pixels g, i is checked, and if any one of the surrounding adjacent pixels g, i is the color opposite to the target pixel X (white in this case). , The figure (b)
As shown in, the divided pixels x0 and x1 are set to white, and the divided pixels x2 and x3 are set to black. in this way,
"Setting the divided pixel to the color opposite to the color of the pixel of interest" is referred to as "divided pixel color correction" in the following description, and FIG.
In this case, the number of divided pixels to be set to the color opposite to the color of the pixel of interest, that is, a pattern with a large amount of divided pixel color correction is set. When both the neighboring pixels g and i have the same color as the target pixel X (black in this case), the divided pixel x0 is white and the divided pixel x0 is white as shown in FIG. A pattern with a small amount of pixel color correction for setting x1, x2, and x3 to black is set. In addition,
In FIG. 2A, a pixel marked with Δ indicates that the content may be black and white, a pixel marked with parallel diagonal lines (hatched) indicates black, and a blank pixel indicates white. (The same applies hereinafter).

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 3A, the colors of the surrounding neighboring pixels b and c are checked, and one of the surrounding neighboring pixels b and c becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x0 and x2 are set to white and the divided pixels x1 and x3 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels b and c are also set.
Are both the same color as the pixel of interest X (black in this case), the divided pixel x2 is white and the divided pixels x0, x1, x3 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 4A, the colors of the surrounding neighboring pixels h and j are checked, and one of the surrounding neighboring pixels h and j becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x0 and x1 are set to white and the divided pixels x2 and x3 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels h, j
Are both the same color as the pixel of interest X (black in this case), the divided pixel x3 is white and the divided pixels x0, x1, x2 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 5A, the colors of the surrounding neighboring pixels n and o are checked, and one of the surrounding neighboring pixels n and o becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x1 and x3 are set to white and the divided pixels x0 and x2 are set to black, as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels n, o
Are both the same color as the pixel of interest X (black in this case), the divided pixel x1 is white and the divided pixels x0, x2, and x3 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 6A, the colors of the surrounding neighboring pixels f and h are checked, and one of the surrounding neighboring pixels f and h becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x0 and x1 are set to white and the divided pixels x2 and x3 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels f and h are set.
Are both the same color as the pixel of interest X (black in this case), the divided pixel x1 is white and the divided pixels x0, x2, and x3 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 7A, the colors of the surrounding neighboring pixels n and o are checked, and one of the neighboring neighboring pixels n and o becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x0 and x2 are set to white and the divided pixels x1 and x3 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels n, o
Are both the same color as the pixel of interest X (black in this case), the divided pixel x0 is white and the divided pixels x1, x2, and x3 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 8A, the colors of the surrounding neighboring pixels i and k are checked, and one of the surrounding neighboring pixels i and k becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x2 and x3 are set to white and the divided pixels x0 and x1 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels i, k
Are both the same color as the pixel of interest X (black in this case), the divided pixel x2 is white and the divided pixels x0, x1, x3 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 9A, the colors of the neighboring pixels c and d are checked, and one of the neighboring pixels c and d becomes the target pixel X. If the colors are opposite (white in this case), the divided pixels x0 and x2 are set to white and the divided pixels x1 and x3 are set to black as shown in FIG. A pattern with a large amount of color correction is set, and surrounding neighboring pixels c and d are set.
Are both the same color as the pixel of interest X (black in this case), the divided pixel x3 is white and the divided pixels x0, x1, x2 are black, as shown in FIG. A pattern with a small correction amount of the divided pixel color to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 10A, the colors of the surrounding neighboring pixels h and j are checked, and one of the surrounding neighboring pixels h and j becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
As shown in FIG. 5, a pattern with a large amount of color correction for divided pixels is set in which the divided pixels x0 and x1 are set to white and the divided pixels x2 and x3 are set to black.
When both j have the same color as the pixel of interest X (white in this case), the divided pixel x3 is black and the divided pixels x0, x1, x2 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 11A, the colors of the surrounding neighboring pixels n and o are checked, and one of the neighboring neighboring pixels n and o becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
, A divided pixel x0, x2 is set to white, and divided pixels x1 and x3 are set to black, and a pattern with a large amount of divided pixel color correction is set.
When both o have the same color as the pixel of interest X (white in this case), the divided pixel x1 is black and the divided pixels x0, x2, and x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 12A, the colors of the surrounding neighboring pixels g and i are checked, and one of the surrounding neighboring pixels g and i becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
As shown in FIG. 3, a pattern with a large amount of color correction for the divided pixels is set in which the divided pixels x2 and x3 are set to white and the divided pixels x0 and x1 are set to black.
If both i have the same color as the pixel of interest X (white in this case), the divided pixel x0 is black and the divided pixels x1, x2, and x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 13A, the colors of the surrounding neighboring pixels b and c are checked, and one of the surrounding neighboring pixels b and c becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
As shown in FIG. 5, a pattern with a large amount of color correction of divided pixels is set in which the divided pixels x1 and x3 are set to white and the divided pixels x0 and x2 are set to black.
When both c have the same color as the pixel of interest X (white in this case), the divided pixel x2 is black and the divided pixels x0, x1, x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 14A, the colors of the surrounding neighboring pixels i and k are checked, and one of the surrounding neighboring pixels i and k becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
As shown in FIG. 5, a pattern with a large amount of color correction of divided pixels is set in which the divided pixels x0 and x1 are set to white and the divided pixels x2 and x3 are set to black.
When both k have the same color as the pixel of interest X (white in this case), the divided pixel x2 is black and the divided pixels x0, x1, x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, H and the target pixel X have the pattern shown in FIG. 15A, the colors of the neighboring pixels c and d are checked, and one of the neighboring pixels c and d becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
, A divided pixel x0, x2 is set to white, and divided pixels x1 and x3 are set to black, and a pattern with a large amount of divided pixel color correction is set.
If both d have the same color as the pixel of interest X (white in this case), the divided pixel x3 is black and the divided pixels x0, x1, x2 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 16A, the colors of the surrounding neighboring pixels f and h are checked, and one of the surrounding neighboring pixels f and h becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
As shown in FIG. 6, a pattern with a large amount of color correction for the divided pixels is set in which the divided pixels x2 and x3 are set to white and the divided pixels x0 and x1 are set to black.
When both h have the same color as the pixel of interest X (white in this case), the divided pixel x1 is black and the divided pixels x0, x2, and x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

Further, the central adjacent pixels A, B, C, D, E,
When F, G, and H and the target pixel X have the pattern shown in FIG. 17A, the colors of the surrounding neighboring pixels m and n are checked, and one of the surrounding neighboring pixels m and n becomes the target pixel X. If the colors are opposite (black in this case), the same figure (b)
, The divided pixels x1 and x3 are set to white and the divided pixels x0 and x2 are set to black, and a pattern with a large amount of divided pixel color correction is set.
When both n have the same color as the target pixel X (white in this case), the divided pixel x0 is black and the divided pixels x1, x2, and x3 are white, as shown in FIG. A pattern with a small amount of divided pixel color correction to be set is set.

As described above, in this embodiment, the contents of the image including the pixel of interest X are set to the central adjacent pixels A, B, C, and
D, E, F, G, H and surrounding neighboring pixels a, b, c,
d, e, f, g, h, i, j, k, l, m, n, o, p
Since it is determined with reference to, it is possible to perform finer smoothing processing, and it is possible to significantly improve the image quality of the image after the pixel density conversion.

FIG. 18 shows a pixel density conversion device according to an embodiment of the present invention.

In FIG. 1, the data input unit 1 inputs fine resolution image data FID from an information source (not shown), and the image data FID input via the data input unit 1 is for one line. In addition to being added to the line buffer 2 having a storage capacity, it is also added to the divided pixel color correction degree determination unit 3.

The output data of the line buffer 2 is added to the divided pixel color correction degree determination unit 3, the divided pixel color correction determination unit 4, and the line buffer 5 having a storage capacity for one line. The output data of the line buffer 5 includes a divided pixel color correction degree determination unit 3, a divided pixel color correction determination unit 4, and a line buffer 6 having a storage capacity for one line.
Has been added to. The output data of the line buffer 6 is
Divided pixel color correction degree determination unit 3, divided pixel color correction determination unit 4,
Also, it is added to the line buffer 7 having a storage capacity for one line. The output data of the line buffer 7 is added to the divided pixel color correction degree determination unit 3.

The divided pixel color correction judging section 4 is arranged to detect the image data FI of each line added from the line buffers 2, 5 and 6.
From D, the pixel of interest X and the central adjacent pixels A, B, C,
The data of D, E, F, G, and H are cut out and it is determined whether or not the above-described divided pixel color correction processing is performed. When the determination is made to perform the divided pixel color correction processing, Outputs to that effect and information indicating which of the 16 types of the above-described divided pixel color correction processing corresponds to the divided pixel color correction degree determination unit 3 and the pixel dividing unit 8 and the target pixel X The image data FID of is output to the pixel dividing unit 8.

The divided pixel color correction degree judging unit 3 determines the surrounding adjacent pixels a, from the image data FID of each line added from the data input unit 1 and the line buffers 2, 5, 6, 7.
b, c, d, e, f, g, h, i, j, k, l, m,
n, o, p are cut out, and the magnitude of the divided pixel color correction amount is determined based on the information notified from the divided pixel color correction determination unit 4, and the determination result is output to the pixel division unit 8. .

The pixel division unit 8 includes a division pixel color correction determination unit 4
When the fact that the divided pixel color correction processing is to be performed and the type of the divided pixel color correction processing are notified from, the information is input from the divided pixel color correction determination unit 4 based on the information notified from the divided pixel color correction degree determination unit 3. Each color of the divided pixels x0, x1, x2, x3 obtained by dividing the target pixel X into four is determined, and based on the determination result, each divided pixel x0, x1,
x2 and x3 super fine resolution image data SF
Form D. Further, when the divided pixel color correction determination unit 4 does not notify the information that the divided pixel color correction processing is performed, the image data FID of the pixel of interest X input from the divided pixel color correction determination unit 4 is used as it is as the divided pixels x0, x1 ,. x
It is set to the image data SFD of 2, x3.

Then, the pixel dividing unit 8 divides the divided pixels x0,
x1 image data SFD with super fine resolution 1
The image data SFD of the divided pixels x2 and x3 is output to the line buffer 9 having a storage capacity of one line and the line buffer 9 having a storage capacity of one line of super fine resolution.

The image data SFD output from the line buffers 9 and 10 is transferred via a data output unit 11 to a not-shown next stage device such as an image recording device.

With the above configuration, the image data FID to be converted into the pixel density is input through the data input unit 1 and sequentially stored in the line buffer 2, and the data stored in the line buffer 2 is sequentially stored in the line buffer 5. , The stored contents of the line buffer 5 are sequentially stored in the line buffer 6,
The stored contents of the line buffer 6 are sequentially stored in the line buffer 7, and the input data of the data input unit 1 and the output data of the line buffers 2, 5, 6, 7 are added to the divided pixel color correction degree determination unit 3 as well. The output data of the line buffers 2, 5 and 6 are added to the divided pixel color correction determination unit 4.

When the necessary data are available, the divided pixel color correction determination section 4 performs the above-described determination operation to determine that the divided pixel color correction process for the target pixel X is necessary. The content of the divided pixel color correction processing is notified to the divided pixel color correction degree determination unit 3 and the pixel dividing unit 8.

As a result, the divided pixel color correction degree determination unit 3
As described above, determines whether to increase or decrease the divided pixel color correction amount of the divided pixel color correction process, and notifies the pixel division unit 8 of the determination result.

As a result, the pixel division unit 8 receives the information notified from the division pixel color correction determination unit 4 at that time, and
Based on the information notified from the divided pixel color correction degree determination unit 3, the target pixel X input from the divided pixel color correction determination unit 4
Image data FID and divided pixels x0, x1, x2, x3
The relationship between the image data SFD to be set to is determined, the corresponding image data SFD is formed, and the line buffers 9 and 10 are formed.
Output to.

Then, the output data of the line buffers 9 and 10 are output to the next stage device as image data SFD of super fine resolution via the data output unit 11.

In this way, in this embodiment, when the pixel data of the fine resolution image data FID is converted into the image data SFD of the super fine resolution, the contents of the image of the central pixel X which is the conversion target are center-adjacent. Pixel A,
B, C, D, E, F, G, H and surrounding neighboring pixels a,
b, c, d, e, f, g, h, i, j, k, l, m,
The divided pixels x0, x1, x are identified by referring to n, o, p.
Since the contents of 2 and x3 are set, it is possible to more appropriately smooth the image of the boundary of the oblique line of any angle and the boundary of the uneven portion, and the image quality of the converted image is greatly improved. can do.

Next, a description will be given of an embodiment in which the pixel density conversion of the standard resolution image into the super fine resolution image is performed.

In this case, as shown in FIG. 19A, the standard pixel of interest X to be subjected to the pixel density conversion, and the adjacent pixels A, B, C, which are adjacent to the target pixel X, are provided.
Considering a pixel matrix composed of D, E, F, G, and H, as shown in FIG. 7B, divided pixels x0, x1, x2, x3, x of superfine resolution after conversion of the target pixel X.
Consider 4, x5, x6, x7.

In this embodiment, according to the color of the target pixel X,
Further, when the pixel of interest X is located at the edge of the image, the divided pixels x0, x1, x are divided according to the direction of the edge.
Colors of pixels of 2, x3, x4, x5, x6, and x7 are set.

That is, the divided pixels x0, x1, x2, x3, x4, x5, x6, x7 are selected according to the color of the target pixel X.
20 to 23 show an example in which the color of the pixel is set.

First, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 20A, as shown in FIG. 20B, the divided pixels x0, x1, and
x2, x3, and x4 are set to the same color as the target pixel X (white in this case), and the divided pixels x5, x6, and x7 are set to the target pixel X.
Set to the opposite color (black in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 21A, as shown in FIG.
x3, x4, x5, x6, and x7 are set to the same color as the target pixel X (black in this case), and the divided pixel x0 is set to the target pixel X.
Set to the opposite color (white in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 22A, the divided pixels x3, x4, as shown in FIG.
x5, x6, and x7 are set to the same color as the target pixel X (white in this case), and the divided pixels x0, x1, and x2 are set to the target pixel X.
Set to the opposite color (black in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 23A, as shown in FIG. 23B, the divided pixels x0, x1, and
x2, x3, x4, x5, and x6 are set to the same color as the target pixel X (black in this case), and the divided pixel x7 is set to the target pixel X.
Set to the opposite color (white in this case).

That is, in this case, if the target pixel X is white, the division pixel color correction degree is large, and if the target pixel X is black, the division pixel color correction degree is small.

When the pixel of interest X is located at the edge of the image, the divided pixels x0, x depending on the direction of the edge.
24 to 27 show examples in which the colors of the pixels of 1, x2, x3, x4, x5, x6, and x7 are set.

First, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 24A, as shown in FIG. 24B, the divided pixels x0, x1, and
x2, x3, x4, x5, and x6 are set to the same color as the target pixel X (white in this case), and the divided pixel x7 is set to the target pixel X.
Set to the opposite color (black in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 25 (a), as shown in FIG. 25 (b), divided pixels x3, x4,
x5, x6, and x7 are set to the same color as the target pixel X (black in this case), and the divided pixels x0, x1, and x2 are set to the target pixel X.
Set to the opposite color (white in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 26A, as shown in FIG.
x5, x6, and x7 are set to the same color as the target pixel X (white in this case), and the divided pixels x0, x1, and x2 are set to the target pixel X.
Set to the opposite color (black in this case).

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have the pattern of FIG. 27A, as shown in FIG. 27B, the divided pixels x0, x1, and
x2, x3, x4, x5, and x6 are set to the same color as the target pixel X (black in this case), and the divided pixel x7 is set to the target pixel X.
Set to the opposite color (white in this case).

That is, in this case, when the target pixel X has the same color as the adjacent pixel G at the upper edge portion, the division pixel color correction degree is increased, and the target pixel X has the adjacent pixel portion at the lower edge portion. In the case of the same color as B, the division pixel color correction degree is reduced.

When such divided pixel color correction processing is performed, for example, when an image of standard resolution has diagonal lines with a certain angle as shown in FIG. 28A, a super image formed by smoothing processing of a conventional method is performed. The fine resolution image is as shown in FIG. 7B, and the angle of the diagonal lines is not constant.

On the other hand, when the intensity of the divided pixel color correction degree is changed depending on the color of the pixel of interest X, the image of the super fine resolution has a constant angle of diagonal lines as shown in FIG. Become.

When the strength of the division pixel color correction degree is changed depending on the direction of the edge portion where the pixel of interest X is located,
In the image of super fine resolution, the angle of diagonal lines is constant as shown in FIG. The figure (e)
Indicates the pixel size of standard resolution.

As described above, in this embodiment, it is possible to prevent a situation in which the image quality of the image is deteriorated when the image of the standard resolution is converted into the image of the super fine resolution and the image quality is improved. Images with super fine resolution can be obtained.

FIG. 29 shows an example of a pixel density conversion device according to this embodiment.

In the figure, the image data S of standard resolution
The ID is input via the data input unit 15, and is added to the comparison division unit 16 and the line buffer 17 having a storage capacity for one line.

The output data of the line buffer 17 is added to the comparison division unit 16 and the line buffer 18 having a storage capacity for one line.
The output data of 8 are added to the comparison division unit 16.

The divided pixel color correction pattern storage unit 19 applies the above-described divided pixel color correction processing to the pattern of the target pixel X and the adjacent pixels A, B, C, D, E, F, G and H.
The relationship between the converted target pixel X and the divided pixels x0, x1, x2, x3, x4, x5, x6, x7 of the super fine resolution is stored.

The comparison division unit 16 refers to the storage data of the division pixel color correction pattern storage unit 19 on the basis of the standard resolution image data SID input from the data input unit 15 and the line buffers 17 and 18, and determines the division pixel color. It is determined whether or not the correction processing is performed, and when the divided pixel color correction processing is performed, the divided pixels x0, x1, x2, x
3, x4, x5, x6, x7 are set to the contents stored in the divided pixel color correction pattern storage unit 19 corresponding to the pattern for which the divided pixel color correction is determined, and when the divided pixel color correction process is not performed, the pixel of interest is selected. The same value as X is set to the values of the divided pixels x0, x1, x2, x3, x4, x5, x6, x7.

The image data of the divided pixels x0 and x1 is stored in the line buffer 20, the image data of the divided pixels x2 and x3 is stored in the line buffer 21, the image data of the divided pixels x4 and x5 is stored in the line buffer 22, and the divided pixel x6. , X7
The image data of 1 is output to the line buffer 23.

Line buffers 20, 21, 22, 23
Has a recording capacity for one line of super fine resolution, and its output data is sent to the next stage device through the data output section 24 to the image data S of super fine resolution.
It is output as FD.

With the above configuration, the image data SID to be converted into the pixel density is input through the data input unit 15 and sequentially stored in the line buffer 17, and the line buffer 17
The stored data is sequentially stored in the line buffer 18, and the input data of the data input unit 15 and the output data of the line buffers 17 and 18 are added to the comparison division unit 16.

When the necessary data are available, the comparison / dividing unit 16 performs the above-described determination operation to determine the pixel of interest X.
When it is determined that the divided pixel color correction processing of is necessary,
Divided pixel color correction data corresponding to the pattern determined at that time is extracted from the divided pixel color correction pattern storage unit 19 and divided pixels x0, x1, x2, x3, and x, respectively.
When the values of 4, x5, x6, and x7 are set and it is determined that the divided pixel color correction processing is not performed, the same value as the pixel of interest X is set to the divided pixels x0, x1, x2, x3, x.
Set to the value of 4, x5, x6, x7.

In this way, the comparison division unit 16 divides the divided pixels x0, x1, x2, x3, x4, x5, x6, x7.
When the value of is set, the image data of the corresponding pixel is output to the line buffers 20, 21, 22, and 23, respectively.

As a result, the image data of the super fine resolution after the pixel density conversion is completed is converted into the line buffer 2.
0, 21, 22, 23, and further, via the data output unit 24, as image data SFD to the next stage device.

The divided pixel color correction pattern storage unit 19
20 to 23 may be either of the divided pixel color correction mode shown in FIGS. 20 to 23 or the divided pixel color correction mode shown in FIGS.
If both are stored, it is possible to appropriately select one of the divided pixel color correction modes. The selection can be made by the type of image or user setting.

By the way, when converting an image of fine resolution into an image of semi-super fine resolution, FIG.
The target pixel X shown in 0 (a) is converted into two upper and lower divided pixels x0 and x1 as shown in FIG.

For example, the image pattern shown in FIG. 31 appears in both the non-halftone image and the halftone image. Conventionally, one of the causes of deterioration of image quality by applying smoothing processing to a halftone image is that such an image pattern is simply smoothed.

Therefore, in this embodiment, the divided pixel color correction processing as shown in FIGS. 32 to 35 is performed for the halftone image, and the non-halftone image is as shown in FIGS. 36 to 39. By performing different divided pixel color correction processing, it is possible to prevent deterioration of the image quality of the halftone image after the smoothing processing and to appropriately perform the smoothing processing on the non-halftone image.

That is, for the halftone image, in the case where the pixel of interest X and the adjacent pixels A, B, C, D, E, F, G and H have a pattern as shown in FIG. )
As shown in, the divided pixel x0 is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 33A, as shown in FIG.
Is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 34A, as shown in FIG.
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 35A, as shown in FIG.
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

On the other hand, for the non-halftone image, in the case where the pixel of interest X and the adjacent pixels A, B, C, D, E, F, G and H have a pattern as shown in FIG. As shown in b), the divided pixel x0 is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 37 (a), as shown in FIG. 37 (b), the divided pixel x0
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 38A, as shown in FIG.
Is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 39A, as shown in FIG.
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

FIG. 40 shows an example of a pixel density conversion device according to this embodiment.

In the figure, the fine resolution image data FID is input through the data input unit 30, and is input to the comparison unit 31 and the line buffer 32 having a storage capacity for one line of the image data FID.

The output data of the line buffer 32 is added to the comparison unit 31 and is also input to the line buffer 33 having a storage capacity for one line of the image data FID. The output data of the line buffer 33 is added to the comparison unit 31.

The divided pixel color correction pattern storage unit 34 includes a data table (not shown) showing the relationship between the divided pixel color correction pattern for the above-mentioned halftone image and the divided pixel for color inversion, and the division for the non-halftone image. A data table (not shown) representing the relationship between the pixel color correction pattern and the color-reversed divided pixels is stored.

Image mode data PMD designating whether the input data is a halftone image or a non-halftone image is added to the comparison unit 31 by a control means (not shown). When the halftone image is designated by the image mode data PMD, the data table for the halftone image stored in the divided pixel color correction pattern storage unit 34 is referred to, and the data input unit 30 and the line buffers 32 and 33 are referred to. Based on the image data FID for three lines added from, it is determined whether or not the pixel of interest X is a pattern for correcting the divided pixel color. If it is determined that the pattern is the divided pixel color correction pattern,
Information indicating that and divided pixel x0 at that time,
Information indicating the divided pixel to be inverted in x1 is output to the pixel division unit 35. Further, the comparison unit 31 outputs the data of the target pixel X to the pixel division unit 35.

The pixel division unit 35 divides the divided pixel x based on the data of the target pixel X added from the comparison unit 31.
The contents of 0 and x1 are set, and when the comparison unit 31 notifies the detection of the divided pixel color correction pattern and the inversion pixel, the color of the informed divided pixel is inverted. Then, the image data SSD of the divided pixels x0 and x1 thus formed is output to the line buffers 36 and 37 having a storage capacity for one line of the image data SSD of the semi-super fine resolution.

The output data of the line buffers 36 and 37 is sent to the next stage device (not shown) by the data output section 38.
It is output as image data SSD of semi-super fine resolution.

With the above configuration, the image data FID to be converted into the pixel density is input through the data input unit 30 and sequentially stored in the line buffer 32, and the line buffer 32 is stored.
The storage data of 1 is sequentially stored in the line buffer 33, and the input data of the data input unit 30 and the output data of the line buffers 32 and 33 are added to the comparison unit 31.

Then, when the necessary data are available, the comparison division unit 31 selects the image mode data P from the data table stored in the division pixel color correction pattern storage unit 34.
When it is determined that the divided pixel color correction processing of the target pixel X is necessary by performing the above-described determination operation with reference to the data table corresponding to MD, it is determined that the divided pixel color correction processing is performed and the inversion pixel is divided into pixels. The unit 35 is notified and the image data FID of the target pixel X is output to the pixel dividing unit 35.

As a result, the pixel division unit 35 forms the image data of the two divided pixels x0 and x1 based on the input image data FID of the target pixel X and is notified when performing the divided pixel color correction processing. When the state of the reversed pixel is reversed and the divided pixel color correction processing is not performed, the image data of the two divided pixels x0 and x1 is formed based on the input image data FID of the target pixel X.

Then, the pixel dividing section 35 outputs the image data of the formed divided pixels x0 and x1 to the line buffers 36 and 37, respectively, whereby the image data of the semi-super fine resolution after the pixel density conversion is completed. The image data SSD is output to the next-stage device via the data output unit 38.

By the way, the image pattern as shown in FIG. 31 appears with a higher probability as the image resolution becomes higher, even if the image type is a non-halftone image, as shown in FIG.

Therefore, for example, when the image before conversion has a standard resolution, the image pattern shown in FIG. 31 is subjected to smoothing processing, and when the image before conversion has a fine resolution, it is shown in FIG. By not performing the smoothing process on the image pattern, the image quality of the image after the pixel density conversion can be improved without determining the image type as in the above-described embodiment.

Here, when converting an image of fine resolution as shown in FIG. 42 (a) into an image of super fine resolution, as shown in FIG. 42 (b), divided pixel x0, When x1 is formed and a standard resolution image is converted into a super fine resolution image, divided pixels x0, x1, x2, and x3 that are vertically divided into four are formed as shown in FIG.

In the present embodiment, when the original image has a fine resolution, the divided pixel color correction processing as shown in FIGS. 43 to 46 is performed, and when the original image has a standard resolution, FIG. By performing the divided pixel color correction processing as shown in FIG. 50, it is possible to prevent the image quality deterioration of the image after the smoothing processing.

That is, when the original image has a fine resolution, the pixel of interest X and the adjacent pixels A, B, C, D,
When E, F, G, and H have a pattern as shown in FIG. 43 (a), as shown in FIG. 43 (b), the divided pixel x0 is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set. The pixel of interest X
Set to the same color as black.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 44A, as shown in FIG.
Is set to white, which is the opposite color to the target pixel X, and the divided pixel x1 is set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 45A, as shown in FIG.
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 45A, as shown in FIG.
Is set to black, which is the opposite color to the target pixel X, and the divided pixel x1 is set to white, which is the same color as the target pixel X.

On the other hand, when the original image has the standard resolution,
The pixel of interest X and adjacent pixels A, B, C, D, E, F,
When G and H have a pattern as shown in FIG. 47A, as shown in FIG. 47B, the divided pixels x0 and x1 are set to white, which is the opposite color to the target pixel X, and the divided pixels x2 and x3 are set. Is set to black which is the same color as the pixel of interest X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 48A, as shown in FIG.
0 and x1 are set to white, which is the opposite color to the target pixel X, and divided pixels x2 and x3 are set to black, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 49A, as shown in FIG.
0 and x1 are set to black, which is the opposite color to the target pixel X, and divided pixels x2 and x3 are set to white, which is the same color as the target pixel X.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 50A, as shown in FIG.
0 and x1 are set to black, which is the opposite color to the target pixel X, and divided pixels x2 and x3 are set to white, which is the same color as the target pixel X.

As described above, by changing the divided pixel color correction pattern at the time of converting the pixel density according to the resolution of the image before conversion, more appropriate smoothing processing can be performed, and the image quality of the image after conversion is improved. can do.

FIG. 51 shows an example of a pixel density conversion device according to this embodiment.

In the figure, the image data DID is input via the data input section 40, and is input to the comparison section 41 and the line buffer 42 having a storage capacity for one line of the image data DID.

The output data of the line buffer 42 is added to the comparison unit 41 and also input to the line buffer 43 having a storage capacity for one line of the image data DID. The output data of the line buffer 43 is added to the comparison unit 41.

The divided pixel color correction pattern storage section 44 stores a data table (not shown) showing the relationship between the divided pixel color correction pattern for the standard resolution image and the divided pixels for color inversion, and for a fine resolution image. A data table (not shown) representing the relationship between the divided pixel color correction pattern and the divided pixels for color inversion is stored.

Resolution mode data CMD designating whether the input data is a standard resolution image or a fine resolution image is added to the comparison unit 41 by a control means (not shown). When the fine resolution is specified by the resolution mode data CMD, the data table regarding the fine resolution stored in the divided pixel color correction pattern storage unit 44 is referred to, and the data input unit 40 and the line buffer 42,
Based on the image data DID for 3 lines added from 43, it is determined whether or not the pixel of interest X is a pattern for correcting the divided pixel color, and if it is determined that it is the divided pixel color correction pattern, information indicating that fact and Information indicating the inverted divided pixel of the divided pixels x0 and x1 at that time is output to the pixel dividing unit 45. When the fine resolution is designated by the resolution mode data CMD, the data table regarding the standard resolution stored in the divided pixel color correction pattern storage unit 44 is referred to, and the data input unit 40 and the line buffers 42 and 43 are referenced. On the basis of the image data DID for three lines added from, it is determined whether or not the pixel of interest X is a pattern for correcting the divided pixel color, and if it is determined that it is the divided pixel color correction pattern, the information indicating that and the information Information indicating the inverted divided pixel among the divided pixels x0, x1, x2, and x3 at that time is output to the pixel dividing unit 46. Further, the comparison unit 41 outputs the data of the target pixel X to the pixel division units 45 and 46.

The pixel division section 45 determines the division pixel x based on the data of the target pixel X added from the comparison section 41.
The contents of 0 and x1 are set, and when the comparison unit 41 notifies the detection of the divided pixel color correction pattern and the inversion pixel, the color of the informed divided pixel is inverted. Then, the image data of the divided pixels x0 and x1 thus formed is stored in the line buffers 47 and 4 having a storage capacity for one line of the image data of the super fine resolution.
Output to 8 respectively.

The pixel division section 46 determines the division pixel x based on the data of the target pixel X added from the comparison section 41.
The contents of 0 and x1 are set, and when the comparison unit 41 notifies the divided pixel color correction pattern detection and the inversion pixel, the color of the informed divided pixel is inverted. Then, the divided pixels x0, x1, formed by this
The x2 and x3 image data are output to the line buffers 47, 48, 49 and 50, respectively, each of which has a storage capacity for one line of the image data of super fine resolution.

The output data of the line buffers 47, 48, 49, 50 is sent to the next stage device (not shown) by the data output unit 51 and the image data SFD of the super fine resolution is output.
Is output as.

With the above configuration, the image data DID to be subjected to the pixel density conversion is input via the data input section 40 and sequentially stored in the line buffer 42.
The stored data is sequentially stored in the line buffer 43, and the input data of the data input unit 40 and the output data of the line buffers 42 and 43 are added to the comparison unit 41.

When the necessary data are available, the comparison division unit 41 refers to the data table corresponding to the resolution mode data CMD among the data tables stored in the divided pixel color correction pattern storage unit 44, When it is determined that the divided pixel color correction processing of the target pixel X is necessary by performing the determination operation described above, the fine resolution is designated by the resolution mode data CMD to the effect that the divided pixel color correction processing is performed and the inversion pixel. In this case, the pixel division unit 45 is notified, and when the standard resolution is designated by the gradation degree mode data CMD, the pixel division unit 46 is notified, and the image data DID of the target pixel X is notified.
Are output to the pixel division units 45 and 46, respectively.

As a result, the pixel dividing section 45 forms the image data of the two divided pixels x0 and x1 based on the input image data DID of the target pixel X, and is notified when performing the divided pixel color correction process. When the state of the reversed pixel is reversed and the divided pixel color correction processing is not performed, the image data of the two divided pixels x0 and x1 is formed based on the input image data FID of the target pixel X.

Then, the pixel dividing section 45 outputs the image data of the respectively formed divided pixels x0 and x1 to the line buffers 47 and 48, whereby the image data of the super fine resolution after the pixel density conversion is completed is Image data SFD is output to the next stage device via the data output unit 51.

Further, when performing the divided pixel color correction processing, the pixel division unit 46 determines four divided pixels x0, x1, x2 based on the input image data DID of the target pixel X.
x3 image data is formed, the notified state of the inversion pixel is inverted, and when the divided pixel color correction processing is not performed, the input image data FI of the pixel of interest X is input.
Based on D, image data of four divided pixels x0, x1, x2, x3 is formed.

Then, the pixel dividing section 46 outputs the image data of the formed divided pixels x0, x1, x2 and x3 to the line buffers 47, 48, 49 and 50, respectively, whereby the pixel density conversion is completed. Image data of super fine resolution is output via the data output unit 51.
The image data SFD is output to the next stage device.

By the way, when converting a standard resolution image into a fine resolution image with a pixel density conversion, as shown in FIG.
As shown in (a) and (b), the target pixel X is divided into two divided pixels x0 and x1.

Then, the smoothing process is performed as shown in FIGS.

That is, the target pixel X and the adjacent pixel A,
When B, C, D, E, F, G, and H have a pattern as shown in FIG. 53A, the divided pixel x0 has a color opposite to that of the target pixel X, as shown in FIG. The divided pixel x1 is set to black and the same color as the target pixel is set to white.

The target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 54A, the divided pixel x0 is changed to black, which is the opposite color to the target pixel X, as shown in FIG. In addition to the setting, the divided pixel x1 is set to white which has the same color as the target pixel.

The target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 55 (a), the divided pixel x0 is set to the same color as the target pixel X, as shown in FIG. 55 (b). At the same time, the divided pixel x1 is set to black, which is the opposite color to the target pixel.

Further, the target pixel X and the adjacent pixels A, B,
When C, D, E, F, G, and H have a pattern as shown in FIG. 56 (a), the divided pixel x0 is set to the same color as the target pixel X, as shown in FIG. 56 (b). At the same time, the divided pixel x1 is set to black, which is the opposite color to the target pixel.

When such smoothing processing is performed, for example, the standard resolution image shown in FIG. 57 (a) is converted into the fine resolution image shown in FIG. 57 (b) after the pixel density conversion. The jaggedness of the image after the pixel density conversion is reduced, and as a result, the image quality is improved.

On the other hand, in the image handled by the group 3 facsimile apparatus, the image obtained by reading with the scanner is combined with the image of the graphic character generated from the character generator or the like, and, for example, the identification information of the transmitting apparatus or the transmission Additional image information such as time information and the number of pages of the transmitted image may be inserted. Such a generated image is very clearly expressed in the image of the reading resolution without deterioration.

When smoothing processing is applied to such a generated image, for example, the image of the canopy portion of the graphic character shown in FIG. 58 (a) becomes a horizontal image of the character as shown in FIG. 58 (b). This results in an image in which the portion between the vertical image and the vertical image is swollen, and the image after pixel density conversion deteriorates.

In order to eliminate such inconvenience, it is advisable to form a pixel-divided image as shown in FIG. 6C without applying smoothing processing to the part of the generated image. .

FIG. 59 shows an example of a pixel density conversion device having such a smoothing process suppressing function.

In the figure, the image data S of standard resolution
The ID is input through the data input unit 60, and the comparison unit 6
1 and the image data SID are input to the line buffer 62 having a storage capacity for one line.

The output data of the line buffer 62 is added to the comparison section 61 and also input to the line buffer 63 having a storage capacity for one line of the image data SID. The output data of the line buffer 63 is added to the comparison section 61.

The divided pixel color correction pattern storage unit 64 stores a data table (not shown) showing the relationship between the divided pixel color correction pattern and the divided pixels to be color-inverted.

Generated image mode data SGN designating that the input data is a generated image is added to the comparing section 61 by a control means (not shown).
When the generated image is specified by the image mode data SGN, the image data S for three lines added from the data input unit 60 and the line buffers 62 and 63.
Image data SID of the target pixel X extracted based on the ID
Is output as it is to the division / inversion unit 65, and when the generated image is specified by the image mode data SGN, the data table stored in the division pixel color correction pattern storage unit 64 is referred to, and the data input unit 60, and , It is determined whether or not it is a pattern for correcting the divided pixel color of the pixel of interest X based on the image data SID for three lines added from the line buffers 62 and 63, and it is determined that it is the divided pixel color correction pattern. Then,
Information indicating that and divided pixel x0 at that time,
Information indicating the divided pixel to be inverted in x1 is output to the division inversion unit 65, and the data of the target pixel X is output to the division inversion unit 65.

The division and inversion unit 65, based on the data of the target pixel X added from the comparison unit 61, divides the division pixel x
The contents of 0 and x1 are set, and when the comparison unit 61 notifies the detection of the divided pixel color correction pattern and the inversion pixel, the color of the informed divided pixel is inverted. Then, the image data of the divided pixels x0 and x1 thus formed is output to the line buffers 66 and 67 having a storage capacity for one line of the fine resolution image data, respectively.

The output data of the line buffers 66 and 67 is sent to the next stage device (not shown) by the data output unit 68.
The image data FID of fine resolution is output.

With the above configuration, the image data SID to be converted into the pixel density is input through the data input unit 60 and sequentially stored in the line buffer 62, and the line buffer 62
The stored data is sequentially stored in the line buffer 63, and the input data of the data input unit 60 and the output data of the line buffers 62 and 63 are added to the comparison unit 61.

When the necessary data are available, the comparison / division section 61 determines that the generated image is the generated image by the generated image mode data SGN.
The image data SID of 1 is output to the division / inversion unit 65. When the generated image mode data SGN specifies that the image is a non-generated image, the determination operation described above is performed by referring to the data table stored in the divided pixel color correction pattern storage unit 64, When it is determined that the divided pixel color correction processing of the pixel X is necessary, the fact that the divided pixel color correction processing is performed and the inversion pixel division and inversion unit 6 are performed.
5 and the image data FID of the pixel of interest X
To the division and inversion unit 65.

Thus, when performing the divided pixel color correction processing, the division inversion unit 65 forms the image data of the two divided pixels x0 and x1 based on the input image data FID of the target pixel X, and is notified. When the state of the reversed pixel is reversed and the divided pixel color correction processing is not performed, the image data of the two divided pixels x0 and x1 is formed based on the input image data FID of the target pixel X.

Then, the division inversion unit 65 outputs the image data of the formed divided pixels x0 and x1 to the line buffers 66 and 67, respectively, so that the image data of the fine resolution after the pixel density conversion is converted into the data. The image data FID is output to the next stage device via the output unit 68.

By the way, in the apparatus of FIG. 59, the comparison unit 61
The generated image mode data SGN is added to the image data from the external device. However, the generated image mode data SGN can be formed based on the input image data SID. The density conversion device is shown in FIG. In the figure, the same parts as those in FIG. 59 and the corresponding parts are designated by the same reference numerals.

In the figure, the image type determination section 69 applies pattern recognition processing or the like to the image data SID input via the data input section 60 to determine that the pixel of interest X input to the comparison section 61 is Whether or not it is a generated image is determined, and the determination result is generated image mode data SG.
N is added to the comparison unit 61.

With the above configuration, the image data SID to be subjected to the pixel density conversion is input via the data input unit 60 and sequentially stored in the line buffer 62.
The stored data is sequentially stored in the line buffer 63, and the input data of the data input unit 60 and the output data of the line buffers 62 and 63 are added to the comparison unit 61 and the image type determination unit 69.

As a result, the image type judging section 69 causes the comparing section 6
It is determined whether the pixel of interest X added to 1 is a pixel of the generated image, and the determination result is output to the comparison unit 61 as generated image mode data SGN.

The comparison division unit 61 divides the image data SID of the target pixel X into the division inversion unit 65 when the generated image mode data SGN specifies that the image is a generated image.
Output to. When the generated image mode data SGN specifies that the image is a non-generated image,
The determination operation described above is performed by referring to the data table stored in the divided pixel color correction pattern storage unit 64,
When it is determined that the divided pixel color correction processing of the target pixel X is necessary, the division inversion unit 65 is notified of the fact that the divided pixel color correction processing is performed and the inversion pixel, and the image data FID of the attention pixel X is divided into the inversion unit. Output to 65.

Thus, when performing the divided pixel color correction processing, the division inversion unit 65 forms the image data of the two divided pixels x0 and x1 based on the input image data FID of the pixel of interest X, and is notified of it. When the state of the reversed pixel is reversed and the divided pixel color correction processing is not performed, the image data of the two divided pixels x0 and x1 is formed based on the input image data FID of the target pixel X.

Then, the division / inversion unit 65 outputs the image data of the formed divided pixels x0 and x1 to the line buffers 66 and 67, respectively, so that the image data of the fine resolution after the pixel density conversion is converted into the data. The image data FID is output to the next stage device via the output unit 68.

Now, another embodiment of the present invention for improving the smoothing effect of the oblique line of an arbitrary angle other than the specific angle in the smoothing process performed at the time of converting the pixel density will be described below.

In this embodiment, as shown in FIG. 61 (a), adjacent pixels B, C, D, G, H, K, L and M directly adjacent to the standard pixel of interest X and adjacent pixel B are included. Extended adjacent pixel A adjacent to, adjacent extended pixel E adjacent to adjacent pixel D, extended adjacent pixel F adjacent to adjacent pixel G, extended adjacent pixel I adjacent to adjacent pixel H, extended adjacent pixel adjacent to adjacent pixel K Considering J and the extended adjacent pixel N adjacent to the adjacent pixel M, this standard pixel of interest X is converted into four divided pixels x0, x1, x2, x3 of super fine resolution.

First, the adjacent pixels B, C, D, G, H, K,
With reference to L and M, it is determined whether or not the pixel of interest X is located at the step of the image as shown in FIGS. 62 and 63.

That is, the target pixel X and the adjacent pixel B,
When C, D, G, H, K, L, and M match the image pattern of FIG. 62 (a), as shown in FIG. 62 (b),
The divided pixels x0 and x1 are set to white, which is the opposite color to the target pixel X, and the divided pixels x2 and x3 are set to black, which is the same color as the target pixel X.

The target pixel X and the adjacent pixels B, C,
When D, G, H, K, L, and M match the image pattern of FIG. 63A, as shown in FIG. 63B, the divided pixels x0 and x1 have colors opposite to the target pixel X. , And the divided pixels x2 and x3 are set to white of the same color as the pixel of interest X.

Further, the target pixel X and the adjacent pixels B, C, D,
G, H, K, L, M and extended adjacent pixels A, E, F,
With reference to I, J, and N, it is determined whether the target pixel X is a pixel adjacent to the step as shown in FIGS. 64 and 65.

That is, the pixel of interest X, the adjacent pixels B, C,
D, G, H, K, L, M and extended adjacent pixels A, E,
When F, I, J, and N match the image pattern of FIG. 64A, as shown in FIG.
0 and x1 are set to white, which is the opposite color to the target pixel X, and divided pixels x2 and x3 are set to black, which is the same color as the target pixel X. At this time, in the case of reducing the division pixel color correction amount at the time of determining the step adjacent pixel, the division pixel x0 is set to white, which is the opposite color to the attention pixel X, and the division pixel x1 is set, as shown in FIG. , X
2 and x3 are set to black, which is the same color as the pixel of interest X.

Further, the pixel of interest X, the adjacent pixels B, C, D,
G, H, K, L, M and extended adjacent pixels A, E, F,
When I, J, and N match the image pattern of FIG. 65 (a), as shown in FIG. 65 (b), divided pixels x0, x
1 is set to black, which is the opposite color to the target pixel X,
x3 is set to white, which is the same color as the pixel of interest X. At this time, in the case of reducing the division pixel color correction amount at the time of determining the step adjacent pixel, the division pixel x0 is set to black, which is the opposite color to the attention pixel X, and the division pixel x1 is set, as shown in FIG. , X2, x3
Is set to the same color as the target pixel X, that is, white.

For example, a super fine resolution image obtained by smoothing a standard resolution image with conspicuous as shown in FIG. 66 (a) by a conventional method is as shown in FIG. 66 (b). Thus, the image becomes jagged, but when the method of this embodiment is applied, the image can be made jagged as shown in FIG. Further, when the divided pixel color correction and the divided pixel color correction amount at the time of determining a step adjacent pixel are reduced, as shown in FIG. 9D, a better conversion result can be obtained. It should be noted that FIG. 6E shows an example of pixel dimensions of standard resolution.

In this way, by applying the smoothing processing of this embodiment, the image quality of the converted image when the pixel density conversion of the standard resolution image into the super fine resolution image is significantly improved. it can.

FIG. 67 shows an example of a pixel density conversion device according to this embodiment.

In the figure, the standard resolution image data S
The ID is input through the data input unit 70, and the comparison unit 7
1 and the image data SID are input to the line buffer 72 having a storage capacity for one line.

The output data of the line buffer 72 is added to the comparison unit 71 and also input to the line buffer 73 having a storage capacity for one line of the image data SID. The output data of the line buffer 73 is added to the comparison unit 71.

The divided pixel color correction pattern storage unit 74 is provided with a data table (not shown) showing the relationship between the divided pixel color correction pattern for determining the stepped pixel and the divided pixel to be color-inverted, and for the step adjacent pixel determination. The data table (not shown) is stored. As the data table for determining the step adjacent pixel, one of a large divided pixel color correction amount and a small divided pixel color correction amount is stored. It is also possible to store both a large amount of divided pixel color correction and a small amount of divided pixel color correction. In that case, either one can be selected according to the user setting or the like.

The comparing unit 71 refers to the data table for determining the step pixel and the pixel adjacent to the step stored in the divided pixel color correction pattern storage unit 74, and refers to the data input unit 70 and the line buffers 72 and 73. Based on the image data SID for 3 lines added from
Is a divided pixel color correction pattern. If it is determined that the divided pixel color correction pattern is a divided pixel color correction pattern, information indicating that fact and the divided pixels x0, x1, x2, x3 at that time are displayed. Information indicating the divided pixel to be inverted is output to the pixel division unit 75, and the data of the target pixel X is output to the pixel division unit 75.

The pixel division unit 75 determines the division pixel x based on the data of the pixel of interest X added from the comparison unit 71.
The contents of 0, x1, x2, and x3 are set, and when the comparison unit 71 notifies the detection of the divided pixel color correction pattern and the inversion pixel, the informed color of the divided pixel is inverted. Then, the image data of the divided pixels x0, x1, x2, and x3 thus formed are output to the line buffers 76, 77, 78, 79 having a storage capacity for one line of the fine resolution image data, respectively.

The output data of the line buffers 76, 77, 78, 79 are output by the data output section 80 to the next-stage device (not shown) as fine resolution image data FID.

With the above configuration, the image data SID to be subjected to the pixel density conversion is input via the data input unit 70 and sequentially stored in the line buffer 72.
The stored data is sequentially stored in the line buffer 73, and the input data of the data input unit 70 and the output data of the line buffers 72 and 73 are added to the comparison unit 71.

The comparison / division unit 71 performs the above-mentioned determination operation with reference to the stepped pixel determination data table and the stepped adjacent pixel determination data table stored in the divided pixel color correction pattern storage unit 74, When it is determined that the divided pixel color correction processing of the pixel of interest X is necessary, the divided inversion unit 75 is notified of the fact that the divided pixel color correction processing is performed and the inversion pixel, and the image data SI
D is output to the division and inversion unit 75.

As a result, when performing the divided pixel color correction processing, the division inversion unit 75 determines the four divided pixels x0, x1, based on the input image data FID of the target pixel X.
When the image data of x2 and x3 is formed, the notified state of the inverted pixel is inverted, and when the divided pixel color correction processing is not performed, four divided pixels are generated based on the input image data FID of the pixel of interest X. x0, x1, x2
x3 image data is formed.

Then, the division / inversion unit 75 outputs the image data of the formed divided pixels x0, x1, x2, x3 to the line buffers 76, 77, 78, 79, respectively, whereby the pixel density conversion is completed. Image data of super fine resolution is output via the data output unit 80.
The image data SFD is output to the next stage device.

By the way, in each of the above-described embodiments, the size of the pixel matrix that defines the adjacent pixel group, the peripheral adjacent pixel group, and the extended adjacent pixel group used for detecting the divided pixel color correction pattern is the same as that of each of the above-mentioned examples. The present invention is not limited to the example, and an appropriate one can be used.

[0187]

As described above, according to the present invention,
Since the color of the divided pixels is corrected and set in the image portion of the shaded portion and the uneven portion at an arbitrary angle, the image quality of the image after the pixel density conversion is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a relationship between a reference pixel matrix group of original data and divided pixels according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 3 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 4 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 5 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 6 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 7 is a schematic diagram showing an example of a divided pixel color correction divided pixel color correction pattern.

FIG. 8 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 9 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 10 is a schematic view showing an example of a divided pixel color correction pattern.

FIG. 11 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 12 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 13 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 14 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 15 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 16 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 17 is a schematic diagram showing an example of a divided pixel color correction pattern.

FIG. 18 is a block diagram showing a pixel density conversion device according to an embodiment of the present invention.

FIG. 19 is a schematic diagram showing a relationship between a reference pixel matrix group of original data and divided pixels according to another embodiment of the present invention.

FIG. 20 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 21 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 22 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 23 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 24 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 25 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 26 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 27 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 28 is a schematic diagram for explaining the effect of the present embodiment.

FIG. 29 is a block diagram showing a pixel density conversion device according to this embodiment.

FIG. 30 is a schematic diagram showing a relationship between a reference pixel matrix group of original data and divided pixels according to still another embodiment of the present invention.

FIG. 31 is a schematic diagram showing an example of an image pattern that causes image deterioration.

FIG. 32 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 33 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 34 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 35 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 36 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 37 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 38 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 39 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 40 is a block diagram showing a pixel density conversion device according to this embodiment.

FIG. 41 is a graph for explaining the frequency of appearance of image patterns that cause image deterioration.

FIG. 42 is a schematic diagram showing a relationship between a reference pixel matrix group of original data and divided pixels according to still another embodiment of the present invention.

FIG. 43 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 44 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 45 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 46 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 47 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 48 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 49 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 50 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 51 is a block diagram showing a pixel density conversion device according to the present embodiment.

FIG. 52 is a schematic diagram showing the relationship between a reference pixel matrix group of original data and divided pixels according to another embodiment of the present invention.

FIG. 53 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 54 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 55 is a schematic view showing another example of a divided pixel color correction pattern.

FIG. 56 is a schematic diagram showing another example of a divided pixel color correction pattern.

FIG. 57 is a schematic diagram for explaining the effect of smoothing processing.

FIG. 58 is a schematic diagram for explaining the effect of the present embodiment.

FIG. 59 is a block diagram showing an example of a pixel density conversion device according to the present embodiment.

FIG. 60 is a block diagram showing another example of the pixel density conversion device according to the present embodiment.

FIG. 61 is a schematic diagram showing a relationship between a reference pixel matrix group of original data and divided pixels according to still another embodiment of the present invention.

FIG. 62 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 63 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 64 is a schematic diagram showing still another example of a divided pixel color correction pattern.

FIG. 65 is a schematic view showing still another example of a divided pixel color correction pattern.

FIG. 66 is a schematic diagram for explaining the effect of the present embodiment.

FIG. 67 is a block diagram showing a pixel density conversion device according to the present embodiment.

Claims (8)

(57) [Claims] 1. An image processing method for dividing each pixel of binary image data into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data, wherein a center adjacent to a pixel of interest to be processed. Depending on the black-and-white pattern of the adjacent pixels and a part of the black-and-white pattern of the surrounding adjacent pixels adjacent to the outer area of the central adjacent pixel, the colors of the plurality of divided pixels obtained by dividing the target pixel are shaded or uneven. Is set so as to be smoothed in a desired manner, and whether or not the divided pixel is set to a color opposite to the color of the pixel of interest according to the black-and-white pattern of the central adjacent pixel. The image processing method is characterized in that the determination is made and the colors of the plurality of divided pixels are set according to a black-and-white pattern of a part of the surrounding adjacent pixels. 2. An image processing method for dividing each pixel of binary image data into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data. Depending on the black-and-white pattern of the pixels, the colors of the plurality of divided pixels obtained by dividing the target pixel are set so as to smooth the image of the oblique line or the uneven portion in a desired mode, and in the setting, An image processing method, wherein the number of divided pixels to be set to a color opposite to the color of the pixel of interest is set according to the color of the pixel and the black-and-white pattern of the surrounding pixels. 3. An image processing method in which each pixel of binary image data is divided into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data. According to the black-and-white pattern of a plurality of surrounding pixels adjacent to, the color of the plurality of divided pixels obtained by dividing the pixel of interest is set so as to smooth the image of the diagonal line or the uneven portion in a desired mode,
In this setting, the number of divided pixels to be set to the color opposite to the color of the target pixel is set according to the protruding direction of the edge portion where the target pixel is located, the color of the target pixel, and the black-and-white pattern of the surrounding pixels. An image processing method characterized by the above. 4. An image processing method for dividing each pixel of binary image data into a plurality of pixels to form image data of pixels smaller than the pixels of the original image data. The color of the plurality of divided pixels obtained by dividing the target pixel is set according to the black-and-white pattern of the pixels so as to smooth the image of the diagonal line or the uneven portion in a desired mode, and in the setting, the black and white are set. An image processing method, wherein a pattern is changed according to an image type of image data to be processed. 5. An image processing method, wherein each pixel of binary image data having different pixel size is divided into a plurality of pixels to form image data of a single size pixel smaller than the pixel of the original image data. According to the black and white pattern of the surrounding pixels adjacent to the target pixel, the color of the plurality of divided pixels obtained by dividing the target pixel is set so as to smooth the image of the diagonal line or the uneven portion in a desired manner. At the same time, in the setting, the black-and-white pattern is changed according to the pixel size of the input image to be processed. 6. Mixed binary image data in which read binary image data obtained by reading by an image input means and generated binary image data generated by a character generator are mixed, and binary image data of smaller pixels In the image processing method for converting to, in accordance with the black and white pattern of the surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black and white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary An image processing method characterized by not performing inversion processing on an image line in the main scanning direction that includes image data. 7. Mixed binary image data in which read binary image data obtained by reading by an image input means and generated binary image data generated by a character generator are mixed, and binary image data of smaller pixels In the image processing method for converting to, in accordance with the black and white pattern of the surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black and white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary An image processing method characterized by not performing inversion processing on a pixel of interest constituting image data. 8. Mixed binary image data in which read binary image data obtained by reading by an image input means and generated binary image data generated by a character generator are mixed, and binary image data of smaller pixels In the image processing method for converting to, in accordance with the black and white pattern of the surrounding pixels adjacent to the target pixel to be processed, it is determined whether or not the target pixel corresponds to a stepped pixel in which the black and white image pattern is stepped. When it is determined that the pixel of interest is a step pixel, the colors of the plurality of divided pixels obtained by dividing the pixel of interest are subjected to inversion processing so as to smooth the step in a desired manner, and the generated binary An image processing method characterized in that the image area of the image data is not inverted.