JP3295561B2 - Image processing device - 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 for converting input binary image data into multivalue image data and outputting the converted image data.

[0002]

2. Description of the Related Art Conventionally, for example, in a facsimile apparatus which is a kind of image processing apparatus, binary image data received from a destination is converted into multi-valued image data to reproduce and record a staircase similar to an original image. Output is known.

As a method of converting the image data into multi-valued image data, for example, image data of 3 × 3 pixels in the vertical and horizontal directions is sequentially extracted from the binary image data, and the density value of one pixel at the center thereof is obtained
There is a method of converting the data into multi-valued image data by correcting the density values of the nine extracted pixels to an average value.

In this case, the binary image data received from the other party is simply binarized by reading characters or the like, or a grayscale image such as a photograph is binarized by pseudo halftone processing. And others.

[0005]

However, when binary image data is converted to multi-valued image data, a portion composed of thin lines, such as characters, is blurred by the multi-value processing to make it difficult to read. However, there has been a problem that the outline of the image becomes ambiguous.

Further, there is a problem that the resolution is substantially reduced by converting the binary image data into multi-valued image data and converting it into multi-valued image data.

The present invention has been made in view of the above circumstances, and converts input binary image data into multivalued image data without lowering the resolution and outputs the converted data, while preserving thin lines and image outlines. It is an object of the present invention to provide an image processing apparatus capable of performing the above.

[0008]

In order to achieve the above object, an image processing apparatus according to claim 1 converts an input binary image data in pixel units into multi-value image data and outputs the same. A resolution conversion means for converting the low-resolution binary image data into high-resolution binary image data; a multi-value conversion means for converting the high-resolution binary image data into high-resolution multi-value image data; Density value comparing means for comparing the respective density values of the high-resolution binary image data and the high-resolution multi-value image data and outputting the image data having the larger density value. It is a feature.

According to another aspect of the present invention, there is provided an image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data. Resolution conversion means for converting the image data into binary image data; thin line pixel determination means for determining whether each pixel of the binary image data is a thin line pixel forming a thin line; Multi-value converting means for converting to multi-valued image data, and for each pixel, when the fine line pixel determining means determines that the pixel is a fine line pixel, outputs the high resolution binary image data and determines that the pixel is not a fine line pixel And a thin line storage unit for outputting the high-resolution multi-valued image data.

According to a third aspect of the present invention, there is provided an image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data. Resolution conversion means for converting the image data into binary image data; edge pixel determination means for determining whether each pixel of the binary image data is an edge pixel forming an outline of an image; Multi-level converting means for converting to high-resolution multi-valued image data, and for each pixel, when the edge pixel determining means determines that the pixel is an edge pixel, the high-resolution binary image data is output. And an edge storage means for outputting the high-resolution multi-valued image data.

According to a fourth aspect of the present invention, there is provided an image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data. Resolution conversion means for converting the image data into binary image data; edge pixel determination means for determining whether each pixel of the binary image data is an edge pixel forming an outline of an image; Multi-level converting means for converting to high-resolution multi-level image data, and comparing the density values of the high-resolution binary image data and the high-resolution multi-level image data for each pixel, Density value comparing means for outputting the image data of each pixel, and for each of the pixels, when the edge pixel determining means determines that the pixel is an edge pixel, the density value comparing means Outputs the image data to be force, if it is determined not to be an edge pixel is characterized in that it comprises an edge storage means for outputting said high-resolution multi-level image data.

[0012]

According to the configuration of the first aspect, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. The high-resolution binary image data is converted into high-resolution multi-value image data by the multi-level converting means. The high-resolution binary image data and the high-resolution multi-value image data are compared for each pixel by a density value comparing unit, and the image data having the larger density value is output.
Thereby, the binary image data can be converted into the multi-valued image data without lowering the resolution, and the outline of the image can be appropriately multi-valued, smoothed, and stored as the outline. .

According to the second aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. Also,
Whether or not each pixel of the input binary image data is a thin line pixel forming a thin line is determined by a thin line pixel determining unit. The high-resolution binary image data is converted into high-resolution multi-value image data by a multi-level conversion unit. The thin line storage unit, when each of the pixels is determined to be a thin line pixel by the thin line pixel determination unit, the high resolution 2
Value image data is output, and if it is determined that the pixel is not a thin line pixel, the high resolution multi-value image data is output. Thereby, the binary image data can be converted into the multi-valued image data without lowering the resolution, and the thin lines are stored without blurring.

According to the third aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. Also,
The edge pixel determination means determines whether each pixel of the input binary image data is an edge pixel forming an outline of the image. The high-resolution binary image data is converted into high-resolution multi-value image data by a multi-level conversion unit. The edge storage unit outputs the high-resolution binary image data for each pixel when the edge pixel determination unit determines that the pixel is an edge pixel, and outputs the high-resolution binary image data when it is determined that the pixel is not an edge pixel. Output value image data. Thereby, the binary image data can be converted into the multi-valued image data without lowering the resolution, and the outline of the image is stored without blurring.

According to the fourth aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. Also,
The edge pixel determination means determines whether each pixel of the input binary image data is an edge pixel forming an outline of the image. The high-resolution binary image data is converted into high-resolution multi-value image data by a multi-level conversion unit. The high-resolution binary image data and the high-resolution multi-value image data are compared for each pixel by a density value comparing unit, and the image data having the larger density value is output. The edge storage unit outputs image data output from the grayscale value comparison unit when each of the pixels is determined to be an edge pixel by the edge pixel determination unit. The high-resolution multi-valued image data is output. Thereby, the binary image data can be converted into the multi-valued image data without lowering the resolution.
The outline of the image is appropriately multivalued and smoothed, and can be stored as the outline.

[0016]

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

First, a first embodiment of the present invention will be described. FIG. 1 shows an image processing apparatus 1 according to a first embodiment of the present invention.
Is shown in FIG.

In FIG. 1, a buffer memory 2 sequentially stores input binary image data in units of 3 × 3 pixels together with eight pixels surrounding the pixel.

The resolution conversion unit 3, which is a resolution conversion means,
By comparing the 3 × 3 pixels stored in the buffer memory 2 with a previously set matching pattern of 3 × 3 pixels, one central pixel of the 3 × 3 pixels stored in the buffer memory 2 is changed to 2 pixels. It is converted to × 2 pixels and converted to twice the resolution.

The buffer memory 4 temporarily stores the high-resolution two-image data converted by the resolution converter 3.

The multi-value conversion unit 5 as multi-value conversion means converts high-resolution two-image data stored in the buffer memory 4 into high-resolution multi-value image data. This conversion is
This is performed by averaging the density value of a pixel with the density value of a 3 × 3 pixel whose pixel is the center pixel.

The density value comparing section 6 as density value comparing means includes:
The density values of the high-resolution two-image data stored in the buffer memory 4 and the high-resolution multi-value image data converted by the multi-value conversion unit 5 are compared for each pixel, and the density value is large. The other image data is output.

With respect to the image conversion processing in the image processing apparatus 1 configured as described above, a case where a part of the input binary image data is 3 × 3 pixels shown in FIG. Let me explain. In addition, FIG.
5 × 5 pixels are shown, including the peripheral pixels of the pixel.

The 3 × 3 pixels including the outline of the image shown in FIG.
The image is converted into 6 × 6 pixels shown in FIG. Note that FIG. 2B shows 8 × 8 pixels including peripheral pixels of 6 × 6 pixels.

The 6 × 6 pixels shown in FIG. 2 (b) are further converted by the multi-value conversion section 5 into the multi-valued 6 × 6 pixels shown in FIG. 2 (c).

The density value comparing section 6 includes a 6 × 6 pixel shown in FIG. 2B and a multi-valued 6 × 6 pixel shown in FIG.
By comparing the density values of × 6 pixels for each pixel, and using the larger density value as the density value of that pixel,
The 6 × 6 pixels shown in FIG. 2D are output.

Thus, the input binary image data is not simply converted to a high resolution and further multi-valued and converted into a mere smooth image, but the outline portion of the image is appropriately multi-valued. And smoothed and stored as contours. Pixels that do not form an outline are converted into an image having appropriate gradation by being appropriately multivalued.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram of an image processing apparatus 1 according to a second embodiment of the present invention.

In the figure, the point different from FIG. 1 showing the configuration of the image processing apparatus 1 of the first embodiment is that a thin line pixel judging section 7 which is a thin line pixel judging means is provided, and a density value comparing section 6 is provided. In that a thin line storing unit 8 as a thin line storing means is provided instead of the thin line storing unit 8.

As will be described later, the thin line pixel determining section 7 determines whether or not the input binary image data in pixel units is a thin line pixel forming a thin line.

When the fine line pixel determining unit 7 determines that each pixel is a fine line pixel, the fine line storing unit 8 stores the high resolution 2 stored in the buffer memory 4.
When the value image data is output and it is determined that the pixel is not a thin line pixel, the high-resolution multi-value image data converted by the multi-value conversion unit 5 is output.

In the image conversion processing in the image processing apparatus 1 configured as described above, a case where a part of the input binary image data is 3 × 3 pixels shown in FIG. Let me explain. In addition, FIG.
5 × 5 pixels are shown, including the peripheral pixels of the pixel.

A 3 × 3 pixel including a thin line shown in FIG. 4A is converted into a 6 × 6 pixel shown in FIG. Note that FIG. 4B shows 8 × 8 pixels including peripheral pixels of 6 × 6 pixels. In addition, the 3 × 3 pixels shown in FIG. 4A are determined for each pixel by the thin line pixel determination unit 7 as shown in FIG. You. That is, the pixel having the density value 1 forming the thin line is determined to be a thin line pixel (Yes), and the pixel having the density value 0 adjacent to the thin line pixel having the density value 1 is also determined to be the thin line pixel (Yes). Yes). Pixels of density value 0 that are not adjacent to the thin line pixel of density value 1 are determined to be not thin line pixels (N
o).

The 6 × 6 pixels shown in FIG. 4B are further converted by the multi-value conversion unit 5 into the multi-valued 6 × 6 pixels shown in FIG. 4C.

The thin line storing section 8 is a memory for storing the data shown in FIG.
× 6 pixels and a multivalued 6 × pixel shown in FIG.
Six pixels are selected in units of 2 × 2 pixels according to the determination result shown in FIG. 4E, and the 6 × pixels shown in FIG.
Outputs 6 pixels.

On the other hand, in the image conversion processing in the case where the input binary image data does not include fine line pixels, a part of the input binary image data is represented by a three-dimensional image shown in FIG. Description will be made by taking a case of × 3 pixels as an example.
Note that FIG. 5A includes peripheral pixels of 3 × 3 pixels,
5 × 5 pixels are shown.

The 3 × 3 pixels shown in FIG. 5A, which do not include the thin line pixels, are
The image is converted into 6 × 6 pixels shown in FIG. FIG. 5B shows 8 × 8 pixels including peripheral pixels of 6 × 6 pixels. Also, the 3 × 3 shown in FIG.
The pixels are determined by the thin line pixel determination unit 7 for each pixel as shown in FIG.
As shown in (e), it is determined whether the pixel is a pixel forming a thin line. In this case, it is determined that all the pixels are not thin line pixels (No).

The 6 × 6 pixels shown in FIG. 5B are further converted by the multi-value conversion section 5 into the multi-valued 6 × 6 pixels shown in FIG. 5C.

The thin line storage unit 8 is a memory for storing the data shown in FIG.
× 6 pixels and a multivalued 6 × pixel shown in FIG.
Six pixels are selected in units of 2 × 2 pixels according to the determination result shown in FIG. 5E, and 6 × 6 pixels shown in FIG.
Output the pixel.

As a result, the input binary image data is not simply converted into a high-resolution image and further multi-valued, and is converted into a simple smooth image as shown in FIG. 4 (d) and FIG. 5 (d), the thin line is stored as a thin line, and the pixels that do not constitute the thin line have appropriate gradation by being multi-valued. Converted to an image.

Next, a third embodiment of the present invention will be described. FIG. 6 shows a block diagram of an image processing apparatus 1 according to the third embodiment of the present invention.

In the figure, the point different from FIG. 3 showing the configuration of the image processing apparatus 1 of the second embodiment is that an edge pixel judging unit 9 as edge pixel judging means is used instead of the thin line pixel judging unit 7.
And that an edge storage unit 10 as edge storage means is provided instead of the thin line storage unit 8.

The edge pixel judging unit 9 performs, as described later,
It is to determine whether or not the input binary image data in pixel units is an edge pixel constituting an edge of the image.

When the edge pixel determination section 9 determines that each pixel is an edge pixel, the edge storage section 10 outputs the high-resolution binary image data stored in the buffer memory 4. If it is determined that the pixel is not an edge pixel, the high-resolution multi-level image data converted by the multi-level conversion unit 5 is output.

Regarding the image conversion processing in the image processing apparatus 1 configured as described above, a case where a part of the input binary image data is 3 × 3 pixels shown in FIG. Let me explain. It should be noted that FIG.
5 × 5 pixels are shown, including the peripheral pixels of the pixel.

The 3 × 3 pixels including the edge pixels constituting the outline of the image shown in FIG. 7A are converted into 6 × 6 pixels shown in FIG. Is converted. FIG. 7B shows 8 × 8 pixels including peripheral pixels of 6 × 6 pixels.

The 3 × 3 pixels shown in FIG. 7A are determined by the edge pixel determination unit 9 for each pixel.
As shown in (e), it is determined whether the pixel is a pixel constituting an edge. That is, when the pixel of interest has a density value of 1, the pixel having a density value of 1
When the number of pixels is one or more and three or less, the pixel of interest is
If it is determined that the pixel is an edge pixel (Yes), and there are no or four pixels having the density value 1, the pixel of interest is determined to be not an edge pixel (No). Similarly,
If the target pixel has a density value of 0, and if one or more pixels having a density value of 0 or more and three or less among pixels vertically and horizontally adjacent to the target pixel, it is determined that the target pixel is an edge pixel. (Yes), when there is no or four pixels having the density value 0, it is determined that the target pixel is not an edge pixel (No).

The 6 × 6 pixels shown in FIG. 7 (b) are further converted by the multi-value conversion unit 5 into the multi-valued 6 × 6 pixels shown in FIG. 7 (c).

The edge storage unit 10 stores the 6 × 6 pixels shown in FIG. 7 (b) and the multivalued 6 × 6 pixels shown in FIG. 7 (c) in FIG. 7 (e). The pixel is selected in units of 2 × 2 pixels according to the determination result, and the 6 × 6 pixels shown in FIG. 7D are output.

On the other hand, when the input binary image data does not include edge pixels, it is shown in FIG. 5A, as in the second embodiment described with reference to FIG. The 3 × 3 pixels not including the edge pixels are converted by the resolution conversion unit 3 into 6 × 6 pixels shown in FIG.

The 3 × 3 pixels shown in FIG. 5A are output by the edge pixel determination unit 9 for each pixel.
As shown in (e), it is determined whether the pixel is a pixel constituting an edge. In this case, it is determined that all the pixels are not edge pixels (No).

The 6 × 6 pixels shown in FIG. 5B are further converted by the multi-level converter 5 into the multi-valued 6 × 6 pixels shown in FIG. 5C.

The edge storage unit 10 stores the 6 × 6 pixels shown in FIG. 5B and the multivalued 6 × 6 pixels shown in FIG. 5C in FIG. 5E. In accordance with the determination result, a selection is made in units of 2 × 2 pixels, and 6 × 6 pixels shown in FIG. 5D are output.

As a result, the input binary image data is not simply converted into a high-resolution image and further multi-valued, and is converted into a simple smooth image as shown in FIG. 7C. 5D and FIG. 7D, the outline of the image is stored as the outline, and the pixels that do not constitute the outline are multi-valued to obtain the proper gradation. Is converted to an image with.

Next, a fourth embodiment of the present invention will be described. FIG. 8 shows a block diagram of an image processing apparatus 1 according to a fourth embodiment of the present invention.

In this figure, the difference from FIG. 1 showing the configuration of the first embodiment is that an edge pixel judging unit 9 as edge pixel judging means is provided and an edge storing unit 10 as edge storing means is different. The point is.

As in the third embodiment, the edge pixel determination section 9 determines whether or not the input binary image data in pixel units is an edge pixel constituting an edge of an image.

When the edge pixel determination section 9 determines that each pixel is an edge pixel, the edge storage section 10 outputs image data output from the density value comparison section 6, If it is determined that the pixel is not an edge pixel, the high-resolution multi-level image data converted by the multi-level conversion unit 5 is output.

Regarding the image conversion processing in the image processing apparatus 1 configured as described above, a case where a part of the input binary image data is 3 × 3 pixels shown in FIG. Let me explain. Note that FIG. 9A shows 3 × 3
5 × 5 pixels are shown, including the peripheral pixels of the pixel.

The 3 × 3 pixels shown in FIG. 9A and including the edge pixels constituting the outline of the image are converted into 6 × 6 pixels shown in FIG. Is converted. Note that FIG. 9B shows 8 × 8 pixels including peripheral pixels of 6 × 6 pixels.

The 3 × 3 pixels shown in FIG. 9A are determined by the edge pixel determination unit 9 for each pixel.
As shown in (f), it is determined whether the pixel is a pixel constituting an edge. That is, when the pixel of interest has a density value of 1, the pixel having a density value of 1
When the number of pixels is one or more and three or less, the pixel of interest is
If it is determined that the pixel is an edge pixel (Yes), and there are no or four pixels having the density value 1, the pixel of interest is determined to be not an edge pixel (No). Similarly,
If the target pixel has a density value of 0, and if one or more pixels having a density value of 0 or more and three or less among pixels vertically and horizontally adjacent to the target pixel, it is determined that the target pixel is an edge pixel. (Yes), when there is no or four pixels having the density value 0, it is determined that the target pixel is not an edge pixel (No).

The 6 × 6 pixels shown in FIG. 9B are further converted by the multi-value conversion section 5 into the multi-valued 6 × 6 pixels shown in FIG. 9C.

The density value comparing section 6 includes a 6 × 6 pixel shown in FIG. 9B and a multi-valued 6 × 6 pixel shown in FIG. 9C.
The 6 × 6 pixels shown in FIG. 9D are output by comparing the density values of the × 6 pixels for each pixel and setting the larger density value as the density value of the pixel.

The edge storage unit 10 includes the multivalued 6 × 6 pixels shown in FIG. 9C and the multi-valued pixels shown in FIG.
The 6 × 6 pixels output from the density value comparing unit 6 are shown in FIG.
According to the determination result shown in (f), selection is made in units of 2 × 2 pixels, and 6 × 6 pixels shown in FIG. 9E are output.

On the other hand, when the input binary image data does not include edge pixels, as in the third embodiment described with reference to FIG.
The 3 × 3 pixels not including the edge pixels shown in
Finally, the data is converted into 6 × 6 pixels shown in FIG.

As a result, the input binary image data is not simply converted to a high-resolution image and further multi-valued to be converted into a simple smooth image as shown in FIG. 9C. As apparent from comparison between FIG. 5D and FIG. 9E, the outline portion of the image is appropriately multivalued and smoothed and stored as an outline, while the pixels that do not constitute the outline are displayed. Is converted into an image having an appropriate gradation by being appropriately multivalued.

[0067]

According to the first aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means, and the high-resolution binary image data is converted to high-resolution binary image data. The data is converted into high-resolution multi-value image data by the multi-value conversion means, and the high-resolution binary image data and the high-resolution multi-value image data are compared for each pixel by the density value comparing means for each pixel. The image data having the larger density value is output, so that the binary image data can be converted into the multi-valued image data without lowering the resolution, and the outline of the image can be appropriately multi-valued. It can be smoothed and saved as a contour.

According to the second aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. The image data is converted into high-resolution multi-valued image data by the multi-value converting means, and the thin line storing means outputs the high-resolution binary image data when the fine line pixel determining means determines that each pixel is a thin line pixel. If it is determined that the pixel is not a thin line pixel, the high resolution multi-valued image data is output, so that the binary image data can be converted into multi-valued image data without lowering the resolution, and the thin line is blurred. Will be saved without.

According to the third aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. The image data is converted into high-resolution multi-valued image data by the multi-value conversion means, and the edge storage means outputs the high-resolution binary image data when each of the pixels is determined to be an edge pixel by the edge pixel determination means. However, when it is determined that the pixel is not an edge pixel, the high-resolution multi-valued image data is output, so that the binary image data can be converted into the multi-valued image data without lowering the resolution, and the outline of the image is Stored without blurring.

According to the fourth aspect of the invention, the input low-resolution binary image data in pixel units is converted into high-resolution binary image data by the resolution conversion means. The high-resolution multi-valued image data is converted into high-resolution multi-valued image data by the multi-value conversion means. The image data having the larger density value is output, and the edge preserving means outputs the image data output from the gray value comparing means when the edge pixel determining means determines that each pixel is an edge pixel. Is output, and if it is determined that the pixel is not an edge pixel, the resolution of the binary image data is reduced to output the high-resolution multi-valued image data. Ku multivalued image data can be converted to, and the contour of the image can be appropriately saved as a contour with smooth are multivalued.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of an image processing procedure of the image processing apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram of an image processing apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of an image processing procedure of an image processing apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing another example of the image processing procedure of the image processing apparatus according to the second embodiment of the present invention.

FIG. 6 is a block diagram of an image processing apparatus according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of an image processing procedure of an image processing apparatus according to a third embodiment of the present invention.

FIG. 8 is a block diagram of an image processing apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of an image processing procedure of an image processing apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1, image processing device 2, buffer memory 3, resolution conversion unit 4, buffer memory 5, multi-value conversion unit 6, density value comparison unit 7, fine line pixel determination unit 8, fine line storage unit 9, edge pixel determination unit 10, edge Storage unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/40-1/409 G06T 5/00 100 H04N 1/387 101

Claims (4)

(57) [Claims] An image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data, wherein a resolution for converting the low-resolution binary image data into high-resolution binary image data A conversion unit; a multi-level conversion unit configured to convert the high-resolution binary image data into high-resolution multi-valued image data; and for each pixel, a high-resolution binary image data and a high-resolution multi-valued image data. An image processing apparatus comprising: a density value comparing unit that compares density values and outputs image data having a larger density value. 2. An image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted binary image data, wherein a resolution for converting the low-resolution binary image data into high-resolution binary image data. Converting means; thin line pixel determining means for determining whether each pixel of the binary image data is a thin line pixel constituting a thin line; and a multi-line converting means for converting the high-resolution binary image data into high-resolution multi-valued image data. The high-resolution binary image data is output when the pixel is determined to be a thin line pixel by the fine line pixel determining unit, and when the pixel is determined not to be a fine line pixel, the high resolution multi An image processing apparatus comprising: thin line storage means for outputting value image data. 3. An image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data, wherein a resolution for converting the low-resolution binary image data into high-resolution binary image data. Converting means; edge pixel determining means for determining whether each pixel of the binary image data is an edge pixel constituting an outline of an image; converting the high-resolution binary image data into high-resolution multi-value image data The high-resolution binary image data is output for each pixel when the pixel is determined to be an edge pixel by the edge pixel determining unit, and when the pixel is determined not to be an edge pixel, the high-resolution binary image data is output. An image processing apparatus, comprising: edge storage means for outputting multi-resolution image data. 4. An image processing apparatus for converting input binary image data in pixel units into multi-value image data and outputting the converted multi-value image data, wherein said resolution converts said low-resolution binary image data into high-resolution binary image data. Converting means; edge pixel determining means for determining whether each pixel of the binary image data is an edge pixel constituting an outline of an image; converting the high-resolution binary image data into high-resolution multi-value image data A density value for comparing the density values of the high-resolution binary image data and the high-resolution multi-value image data with respect to each pixel, and outputting the image data having the larger density value. For the comparison means and for each pixel,
If the edge pixel determination unit determines that the pixel is an edge pixel, the image data output from the grayscale value comparison unit is output. If it is determined that the pixel is not an edge pixel, the high resolution multi-valued image data is output. An image processing apparatus comprising: an edge storage unit.