JPH0832809A - Image processing unit - Google Patents

Abstract

PURPOSE:To apply proper smoothing processing to image data in the case of superimposing a character onto an image part of the image data or the like. CONSTITUTION:An address generating section 10 applies pattern matching to dot patterns around a noted picture element among those of image data of a reference area stored in a shift register 5 based on various pattern conditions. Furthermore, a comparator 8 provides an output of a level 1 when the reference area satisfies the image condition. In this case, when the dot pattern satisfies a long pattern condition, smoothing processing is conducted and when the dot pattern satisfies a short pattern condition, no smoothing processing is conducted. Thus, when a character or the like (satisfying the long pattern condition) is superimposed on the image data (consecutive short patterns), smoothing processing is applied only to the latter without giving effect on the former.

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 suitable for use in a copying machine or the like.

[0002]

2. Description of the Related Art When a binary image is output by a copying machine, a printer or the like, if the resolution of the output device is low, jaggies occur in the shaded area and the image quality deteriorates. On the other hand, the following various smoothing processing techniques have been proposed in order to obtain a high quality image output. For example, Japanese Patent Application Laid-Open No. 53-41115 discloses a technique of converting the monochrome state of a small pixel after resolution conversion by a logical operation of each pixel and its surrounding pixels at the time of resolution conversion.

Further, Japanese Patent Application Laid-Open No. 2-112966 discloses a technique for performing pattern matching between image data obtained from a character generator of a printer and a known pattern for smoothing. For example, assuming that the character "b" is printed,
The dot pattern of the character "b" is output from the character generator. Next, in the quality improvement circuit, each portion of the dot pattern is collated with a plurality of known patterns, and if there is a known known pattern, the pattern subjected to the smoothing process in advance is supplied to the output device. To be done.

By the way, if such smoothing processing is performed unconditionally, a problem may occur. That is, when the image data includes a character portion and an image portion (such as a photograph), if the image portion is subjected to smoothing processing, the gradation characteristics of the image portion deteriorate, and the image quality deteriorates.
Therefore, the following techniques have been proposed in order to avoid the smoothing process on the image part.

First, in Japanese Patent Laid-Open No. 4-189564, the start / end address of the image portion is stored based on the code of the data supplied from the host computer, and the smoothing function is turned on / off based on this address. Techniques for turning off are disclosed. In addition, Japanese Patent Laid-Open No. 268867/1992 discloses a technique in which the density of images is obtained for each predetermined section of image data, and the smoothing function is turned off in a portion where the images are dense. This technique defines a small area of about “16” for a reference area of “11 × 9” dots centered on a pixel of interest,
The density of the reference area is obtained by detecting the characteristics of each small area and then combining the results.

[0006]

However, the above-mentioned technique has various drawbacks as described below.
First, considering the effect of the smoothing processing, in the case of JP-A-53-41115, the image data is
Since the correction is performed on a pixel-by-pixel basis, not only a sufficient effect cannot be obtained, but also unnecessary correction may adversely affect the image quality. Further, since the one disclosed in Japanese Patent Laid-Open No. 2-112966 is intended for image data obtained from a character generator of a printer, it is difficult to apply it to a copying machine or the like. That is, the type of image data obtained from the character generator of the printer is limited,
In a copying machine or the like, the content of image data varies so much that it is difficult to perform sufficient smoothing processing on the image data.

Next, considering the point of avoiding the smoothing process for the image portion of the image data, the one disclosed in Japanese Patent Laid-Open No. 4-189564 requires that the data code be supplied from the host computer. It was impossible to apply it to copiers, etc., where such a code cannot be obtained. In addition, JP-A-4-268867
In the case of the gazette, when characters or line drawings are present in a portion where the image density is high (for example, when characters or line drawings are overlaid on a photographic image, or characters are modified by shading, etc.) In addition, there is a problem that the smoothing function is turned off for such characters. The present invention has been made in view of the above circumstances, and an object thereof is to provide an image processing apparatus that performs appropriate smoothing processing.

[0008]

In order to solve the above problems, according to the structure of claim 1, the image data has a first pattern condition and a first pattern condition that define a state of a pixel column of a predetermined length. Of the second pattern conditions that define the state of the pixel column longer than the condition, the pattern condition determining means for determining which is satisfied, and the content of the smoothing process corresponding to the first pattern condition are described in the first area. Storage means for storing the content of the smoothing processing corresponding to the second pattern condition in the second area, and the case where the first pattern condition is satisfied and the second pattern condition is not satisfied. Applies smoothing processing to the image data based on the contents stored in the first area, while if both the first pattern condition and the second pattern condition are satisfied, Characterized by comprising a smoothing means for performing smoothing processing on the image data based on the contents stored in the second region.

According to the second aspect of the invention, the image data defines the first pattern condition that defines the state of the pixel column of a predetermined length and the state of the pixel column that is longer than the first pattern condition. Pattern condition determining means for determining which of the second pattern conditions is satisfied, image image condition determining means for determining whether the image data satisfies a predetermined image image condition, and the first image condition determining means. Storage means for storing the content of the smoothing processing corresponding to the pattern condition in the first area and storing the content of the smoothing processing corresponding to the second pattern condition in the second area;
If the pattern condition is satisfied, the image data is subjected to smoothing processing based on the contents stored in the second area, and the first pattern condition is satisfied, and the image image condition and the second pattern are satisfied. If both conditions are not satisfied, smoothing processing is performed on the image data based on the content stored in the first area, while both the first pattern condition and the image image condition are satisfied. And a smoothing unit that prohibits the smoothing process when the second pattern condition is not satisfied.

According to a third aspect of the present invention, in the image processing apparatus according to the second aspect, the image image condition determining means further includes a main scanning direction or a sub-scan in a predetermined area of the image data. A difference number output means for outputting the number of times the contents of adjacent pixels along the direction are different, and a comparison means for judging that the image image condition is satisfied when the number of times is equal to or more than a predetermined threshold value. It is characterized by

According to a fourth aspect of the present invention, in the image processing apparatus according to the second aspect, the image data is binary image data composed of black pixels and white pixels,
The image image condition determination means, when the number of black pixels in a predetermined area of the image data is a predetermined value or more,
It is characterized in that it is determined that the image condition is satisfied.

According to a fifth aspect of the present invention, in the image processing apparatus according to the second aspect, the image data is binary image data composed of black pixels and white pixels,
The image image condition determination means determines whether or not the image image condition is satisfied based on the number of times the white / black states are different between adjacent pixels in the image data and the number of black pixels. Is characterized by.

[0013]

According to the first aspect of the invention, when the first pattern condition is satisfied and the second pattern condition is not satisfied, the image data is smoothed based on the contents stored in the first area. Is applied. Here, since the length of the pixel row under the first pattern condition is shorter than that under the second pattern condition, the first pattern condition is satisfied in a relatively large number of places in the image data. As a result, the smoothing process is performed on a relatively large number of places in the image data.

On the other hand, when both the first pattern condition and the second pattern condition are satisfied, the image data is subjected to smoothing processing based on the contents stored in the second area. In the area where the second pattern condition is satisfied, smoothing processing more suited to the state of the image data is performed.

According to the second to fifth aspects, when the image image condition is satisfied, the smoothing process based on the first pattern condition is prohibited. Smoothing processing can be performed without loss. Even in such a case,
Since the smoothing process based on the second pattern condition is executed, it is possible to perform the smoothing process on a portion such as a character overlaid on the image that satisfies the long pattern condition.

[0016]

EXAMPLES A. Example Principle A-1. Smoothing Process First, the contents of the smoothing process will be described with reference to FIG. FIG. 7A shows image data before the smoothing process is performed, and each grid of the grid is a unit of one pixel. Hereinafter, the position of each pixel is the coordinate (a,
b), c, ...) And the coordinates (1, 2, 3, ...) In the sub-scanning direction.
・), For example, "b3". Pixels in which the character "black" is written are all black pixels, and pixels in which nothing is written are all white pixels. Figure 2
In (a), all pixels are all black or all white.

Next, FIG. 2B shows the image data after smoothing the pixels of FIG. 2A. In this figure, some black pixels (hereinafter referred to as intermediate pixels) are
The black part is displayed by hatching. The same figure (a),
When (b) is compared, for example, all black pixels at coordinates c4 to c7 and all white pixels at coordinates c8 to c11 in FIG.
Is converted into an intermediate pixel. The area of the black portion of these intermediate pixels becomes smaller as it goes downward in the sub-scanning direction. In addition, the pixels of the other edge portions are similarly converted.

By the way, paying attention to all black pixels at the left edge portion of FIG. 3A, a pattern in which all black pixels are continuous eight times in the sub-scanning direction and then shifted once in the main scanning direction. ing. On the other hand, according to FIG.
The area of the black portion of each intermediate pixel of c11 to c11 decreases by about “1/8” of one pixel as it goes in the sub-scanning direction. As described above, appropriate smoothing cannot be performed unless the area of the black portion in each intermediate pixel is determined based on the relationship with the surrounding pixels.

For this reason, in the present embodiment, first, "17" pixels in the main scanning direction and "17" pixels in the sub scanning direction are centered on the pixel to be processed (hereinafter referred to as the target pixel) in the image data. An area of 9 "pixels (hereinafter referred to as a reference area) is extracted. Then, it is determined whether or not the dot pattern of the reference area matches any of the plurality of pattern conditions, and if they match, the area of the black portion is set to a value corresponding to the pattern condition.

Here, FIG. 3A shows an example of the pattern condition. This condition is that for the coordinate "i5" of the pixel of interest,
This is satisfied when the coordinates “a5 to i5, i4, j4” in the reference area are white pixels and the coordinates “a6 to i6, j5” are black pixels. Under this condition, the area ratio L of the black portion is set to be “46.0%”, and the result of outputting the pixel of interest at the coordinate “i5” is as shown in FIG. Become. The same processing is performed on the other pixels in the reference area when each pixel becomes the target pixel. 4A to 4F show examples of various pattern conditions and the corresponding black area ratio L. In addition, in these figures, all the omitted parts are "pixels (-) unrelated to processing".

The image data of FIG. 2B is obtained by repeating such pattern matching for each pixel of the image data of FIG. 2A. By the way, the reference area may satisfy a plurality of pattern conditions. For example, if the reference area satisfies the pattern condition of FIG. 3A, the conditions of FIGS. 4D to 4F should be satisfied. In such a case, in the present embodiment, it is considered that only "the longest pattern condition of the effective portion (the portion excluding the pixels not related to the processing)" is satisfied. For example, the length of the effective part of the pattern condition of FIG.
0 ", and those of FIGS. 4D to 4F are" 9 ",
They are "3" and "4". Therefore, as long as the condition of FIG. 3A is satisfied, the black area ratio L is set to “46.0%”.

By the way, although the contents of image data obtained by a copying machine and the like are various, there is a possibility that each part of the image data satisfies the short pattern condition (FIGS. 4E, 4F, etc.). This is high, and thus smoothing processing can be performed to some extent even on complicated image data. Further, when the long pattern condition of the effective portion is simultaneously satisfied as shown in FIG. 3D or FIG. 3A, smoothing processing is performed based on the long pattern condition. A more suitable smoothing process is performed. As described above, in this embodiment, various pattern conditions for the effective portion are set, and the long pattern condition is prioritized and applied, which is effective for image data obtained by a copying machine or the like. It becomes possible to perform smoothing processing.

A-2. Limitation of smoothing process As described above, if the smoothing process is unconditionally performed on the image portion of the image data, the gradation characteristics are deteriorated and the image quality is deteriorated. Therefore, it is necessary to limit the smoothing process. . In this embodiment,
The number of times the pixel color in the reference area changes along the main scanning direction and the sub scanning direction is counted. When the count result is equal to or larger than a predetermined value (for example, "90"), the reference area is considered to be an image portion.

The smoothing process is partially limited for the reference area that is considered to be the image portion. That is, when the long pattern condition of the effective portion is satisfied as shown in FIGS. 4A to 4D, the target pixel is subjected to the smoothing process, but as shown in FIGS. 4E and 4F, it is short. When only the pattern condition (for example, the pattern condition in which the length of the effective portion is “4” or less) is satisfied, the smoothing process is not performed. Since the image portion is formed by repeating a short pattern, this makes it possible to avoid the smoothing process.

On the other hand, when a character or a line drawing is superimposed on the image portion, each pixel forming the character or the like is likely to satisfy a long pattern condition. When the long pattern condition is satisfied, the smoothing process is performed on the pixel. Here is the feature of the present embodiment, and when characters or line drawings are superimposed on the photographic image, or when the characters are modified by shading, the gradation characteristics of the photographic image or the shaded part are not destroyed. It is possible to apply smoothing processing to characters and line drawings.

B. Configuration of Embodiment The configuration of this embodiment will be described below with reference to FIG. In the figure, reference numeral 1 is an image input unit, which reads an original by an image scanner or the like and outputs image data. Reference numeral 2 denotes a binary image conversion unit that converts this image data into binary image data. In this binary image data, black pixels are represented as "1" and white pixels are represented as "0". An image memory 3 stores the converted binary image data. Four
Is an address generator, which stores the binary image data in the image memory 3 by "1" pixels in the main scanning direction and "9" in the sub scanning direction.
An address signal for sequentially accessing in the main scanning direction is output with the pixel region as one unit. Thereby, the binary image data is sequentially read from the image memory 3.

A shift register 5 stores binary image data of "17" pixels in the main scanning direction and "9" pixels in the sub scanning direction. Upon receiving one unit of binary image data from the image memory 3, the shift register 5 stores the contents in "9" registers located at one end in the main scanning direction and the contents of other registers in the main scanning. Shift in the direction. The overflowed data is discarded. As a result, the binary image data of the reference area is stored in the shift register 5. The pixel at the center of the reference area, that is, the value of the target pixel is output as target pixel data CPX.

Next, 6 is an EOR (exclusive OR) circuit group, which calculates and outputs an exclusive OR between pixel data adjacent to each other in the main scanning direction and the sub scanning direction in the reference area. It is composed of many EOR circuits. 7
Is an adder, which adds the output signals of the respective EOR circuits and outputs the result. As an example, the addition result is obtained when only the pixel of interest is black (“1”) and all other pixels are white (“0”) in the reference area. First, the target pixel is adjacent to two pixels in each of the main scanning direction and the sub scanning direction. The four EOR circuits having these pixel data and the pixel data of the target pixel as input signals output "1" signals, but other EOR circuits.
The circuits all output a "0" signal. Therefore, in such a case, the addition result of the adder 7 becomes "4".

Reference numeral 8 denotes a comparator, which compares the addition result of the adder 7 with a threshold value (for example, "90") stored in the register 9, and becomes "1" when the addition result is equal to or more than the threshold value.
In other cases, the condition selection signal PSL that becomes "0" is output. A look-up table 13 stores image data of all black pixels, all white pixels, and various intermediate pixels (black area ratio and arrangement position of black portion), and when the address signal is supplied, the corresponding image data is stored. Output. That is, the image data output from the lookup table 13 is in units of sub-pixels (units smaller than one pixel).
Is used to specify white / black.

An image output unit 14 prints out an image based on the image data supplied from the look-up table 13. The details will be described with reference to FIGS. In FIG. 5, the image output unit 14 includes an ASG (pulse width modulation device with lighting start position control) 141 and an AS.
A laser diode 142 whose lighting timing is controlled by G141, and an electrophotographic image output device 143 that charges a sheet and fixes toner at a charging position at the timing when the laser diode 142 emits light.
It consists of and. The lookup table 13 is
The above image data (black area ratio and black part placement position)
Based on the above, the lighting time signal and the lighting position signal are supplied to the image output unit 14.

Here, the lighting time signal is a signal for designating the lighting time of the laser diode 142 corresponding to the area of the black portion in one pixel. The lighting position signal is "Left", "Right", or "Center".
The laser diode 14 is a three-valued signal that takes
2 is a signal for designating the lighting position of 2, that is, the arrangement position of the black portion. For example, even if the area of the black portion is designated as "50%" by the lighting time signal, the arrangement of the black portion is determined depending on the value of the lighting position signal as shown in FIGS.
It is set as shown in.

An address generator 10 compares the dot pattern of the reference area stored in the shift register 5 with various pattern conditions (see FIG. 4) and finds the longest effective part of the satisfied pattern conditions. The address signal ADL is output based on the pattern condition (hereinafter, referred to as a definite pattern condition). The address signal ADL designates the read address of the look-up table 13. If the address signal ADL is directly supplied to the look-up table 13, the image data having the black area ratio L corresponding to the fixed pattern condition is generated. It will be output from the lookup table 13.

The address generator 10 also outputs a long pattern match signal LMT and a short pattern match signal SMT based on the length of the effective portion of the fixed pattern condition. The long pattern match signal LMT is a signal that becomes "1" when the length of the effective portion is "5" or more, and becomes "0" otherwise. The short pattern match signal SMT is "1" when the length of the effective portion is "4" or less.
The signal is "0" in all other cases. Here, when the dot pattern of the reference area does not satisfy any of the pattern conditions, the address signal ADL is not output, and the short pattern match signal SMT and the long pattern match signal LMT are “0”.

Next, reference numeral 12 is a selector, which selects signals PSL, SMT, L at the selection input terminals SEL1 to SEL4.
MT, CPX are received, and based on the result, any one of the address signals supplied to the data input terminals A to C is selected and output from the output terminal OUT. Here, at the data input terminal A, from the register 11 to the lookup table 13
All black pattern addresses are being supplied. Further, the data input terminal B is similarly supplied with the address of the all-white pattern. The selection conditions in the selector 12 are as shown in Table 1 below.

[0035]

[Table 1]

C. Operation of Embodiment Next, the operation of this embodiment will be described. First, the image input unit 1
When the image data is input from, the image data is converted into binary image data via the binary image conversion unit 2 and stored in the image memory 3. Next, when the address generator 4 sequentially reads out binary image data of one unit (a region of “1” pixels in the main scanning direction and “9” pixels in the sub scanning direction) in the image memory 3, the binary image data is read out. The contents are stored in the shift register 5 while being shifted. Subsequent operations differ depending on the contents of the reference area stored in the shift register 5, and therefore will be described separately.

C-1. Neither pattern condition is satisfied
If the dot pattern in the reference area does not satisfy any of the pattern conditions, both the short pattern match signal SMT and the long pattern match signal LMT become “0”. here,
If the pixel of interest is a black pixel, the pixel of interest data CPX becomes "1". In this case, according to Table 1 (a), the data input terminal A is selected by the selector 12, and the address of the all black pattern is supplied to the lookup table 13.
On the other hand, if the target pixel is a white pixel, the target pixel data CP
X becomes "0". In this case, according to Table 1 (b), the data input terminal B is selected and the address of the all-white pattern is supplied to the lookup table 13. As a result, the image data supplied to the image output unit 14 is the target pixel data C.
All black pattern or all white pattern according to PX,
An image that has not been smoothed is output.

C-2. When long pattern conditions are satisfied
When the defined pattern condition that the length of the combined effective portion is "5" or more is satisfied, the long pattern match signal LMT is set to "1". According to Table 1 (e), in such a case, the data input terminal C is selected regardless of the values of other signals. As a result, the address signal ADL is supplied to the look-up table 13 via the selector 12, and the look-up table 13 outputs the image data relating to the intermediate pixel. That is, the image data subjected to the smoothing process is output from the image output unit 14.

C-3. When the short pattern condition is satisfied
When the fixed pattern condition that the length of the combined effective portion is "4" or less is satisfied, the short pattern match signal SMT is set to "1". Here, if the number of white / black changes in the reference area is greater than or equal to the threshold value, the condition selection signal PSL becomes "1". In this case, according to Tables 1 (c) and 1 (d), the target pixel data CP
Either of the data input terminals A and B is selected according to X.
That is, as in the case where the dot pattern of the reference region does not satisfy any of the pattern conditions, the image output unit 14 outputs an image that has not been subjected to smoothing processing.

On the other hand, if the number of white / black changes in the reference area is less than the threshold value, the condition selection signal PSL becomes "0". In such a case, according to Table 1 (f), the data input terminal C is selected by the selector 12. That is, as in the case where the long pattern condition is satisfied, the image data subjected to the smoothing process is output from the image output unit 14.

Which of the operations described above is executed is determined based on the contents of the reference area in the shift register 5. That is, each time new binary image data is read from the image memory 3 and the contents of the shift register 5 are updated, the selection state of the selector 12 is changed accordingly. Therefore, when image data is stored in the image memory 3 and a character or a line drawing overlaps the image data, the short pattern match signal SMT or the long pattern match is kept while the condition selection signal PSL is fixed at "1". The value of the signal LMT will change.

That is, when the pixel of interest is located in the background portion of the image, the short pattern match signal SMT is "1".
Then, while the image data that has not been subjected to the smoothing process is output, when the pixel of interest is located on a character or line drawing on the image, the long pattern match signal LMT becomes “1”, and Smoothing processing is performed.

As described above, according to this embodiment, when the condition selection signal PSL is fixed at "1", the selection of the selector 12 is made according to the states of the short pattern match signal SMT and the long pattern match signal LMT. Since the state is changed, it is possible to perform the smoothing process on the character or line drawing superimposed on the image while avoiding the smoothing process on the background portion of the image.

When multivalued image data output from the image input section 1 is converted into binary image data via the binary image conversion section 2, notches may occur in the binary image data. By performing the smoothing process according to the present embodiment, it becomes possible to make the notches inconspicuous.

D. Modifications The present invention is not limited to the embodiments described above, and various modifications can be made, for example, as described below.

D-1. Modification 1 In the above embodiment, the image image condition is determined based on whether or not the number of times the pixel color in the reference area changes is equal to or more than a predetermined value, but the image image condition is other than that in the embodiment. May be used. An example thereof will be described with reference to FIGS. FIG. 7 is a block diagram of an image processing apparatus according to the first modification, in which the EOR circuit group 6, the adder 7, the comparator 8 and the registers 9 and 11 in FIG.
5 are provided. Details of the condition determination circuit 15 are shown in FIG. In FIG. 8, reference numeral 151 denotes a black pixel counting circuit, which counts and outputs the number BK of black pixels in the reference area. Further, reference numeral 152 denotes a pixel change point counting circuit, which has the same configuration as the EOR circuit group 6 and the adder 7 in the above-described embodiment, and is the number of times the contents of adjacent pixels in the main scanning direction or the sub scanning direction differ. (Hereinafter, the pixel change point CH
Is output).

An image image determination block 157 determines whether or not the following conditions 1 to 3 are satisfied. Condition 1: CH ≧ A Condition 2: BK ≧ B Condition 3: CH / 2 + C ≧ BK However, in the above Conditions 1 to 3, A is a pixel change point threshold,
B is a black pixel threshold value, and C is a calculation offset, which are stored in the registers 153-155, respectively.

Reference numeral 156 is a condition control mode register,
Whether or not to select the above conditions 1 to 3 is stored for each condition,
The content is output as a condition select signal. In general, all of the conditions 1 to 3 should be selected. Next, 157 is an image image determination block,
It is determined whether the selected one of the conditions 1 to 3 is satisfied. Then, when at least one of the selected conditions is satisfied, the condition selection signal PSL is set to "1", while when none of the selected conditions is satisfied, the condition selection signal PSL is set to "1". Set to 0 ".

The configuration other than the above is the same as that of FIG. That is, also in this modification, the condition selection signal PS
When L is set to "1", the selection state of the selector 12 is changed according to the states of the short pattern match signal SMT and the long pattern match signal LMT, so smoothing processing for the background portion of the image is avoided. While
It is possible to perform a smoothing process on a character or line drawing superimposed on the image.

Furthermore, in the present modification, the condition selection signal PSL is set based on a plurality of conditions, so it is possible to detect the image image more accurately. In particular,
The conditions 2 and 3 are unique to this modification. These conditions are as follows: "In the image part, the number of pixel change points increases monotonically with the increase in the number of black pixels until half the number of pixels in the reference region is reached. In consideration of the fact that when the number of pixels exceeds half, the number of pixel change points tends to decrease monotonously with the increase in the number of black pixels. "And" When the number of black pixels increases, the characters tend not to appear. " It is provided.

D-2. Modification 2 In Modification 1, the condition selection signal PSL is set based on the results of the conditions 1 to 3, but generally, the condition selection signal PSL is set as a function of the number of black pixels BK and the number of pixel change points CH. You may. For example, if the number of black pixels BK is Y
Assuming a plane with the axis and the pixel change point CH as the X axis,
The point (BK, CH) on the plane is specified based on the black pixel number BK and the pixel change point CH in the reference area. If this point (BK, CH) belongs to the hatched area in FIG. 9 (a), (b) or (c), the condition selection signal PSL is set to "0", otherwise the condition selection signal PSL is set. Signal PSL
May be set to "1". Alternatively, a lookup table containing the determination results on the BK / CH plane may be created in advance, and the determination result of the point (BK, CH) may be obtained by referring to the lookup table.

[0052]

As described above, according to the first aspect of the invention, by providing the first pattern condition, it is possible to perform the smoothing process on a relatively large number of places, and the second pattern condition can be applied. It is possible to perform smoothing processing more suitable for the state of the image data on the portion satisfying the condition. Further, according to the configurations of claims 2 to 5, when the image image condition is satisfied, only the smoothing process based on the second pattern condition is executed, so that the characters etc. superimposed on the image are It is possible to perform smoothing processing on the.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an example.

FIG. 2 is a diagram illustrating the operation of the embodiment.

FIG. 3 is an operation explanatory diagram of an example.

FIG. 4 is a diagram illustrating the operation of the embodiment.

5 is a block diagram of the image output unit 14. FIG.

FIG. 6 is an operation explanatory diagram of the image output unit 14.

FIG. 7 is a block diagram of a first modification.

FIG. 8 is a block diagram of the condition determination circuit 15.

FIG. 9 is an operation explanatory diagram of the second modification.

[Explanation of symbols]

10 Address Generation Unit (Pattern Condition Judgment Means, Smoothing Means) 13 Lookup Table (Storage Means) 8 Comparator (Image Image Condition Judgment Means, Comparison Means) 7 Adder (Image Image Condition Judgment Means, Difference Count Output Means) 6 EOR circuit group (image image condition determination means, difference number output means) 12 selector (smoothing means) 15 condition determination circuit (image image condition determination means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G06T 5/00 G06F 15/66 405 15/68 350 (72) Inventor Kenji Hara Hongo, Ebina, Kanagawa Prefecture Address 2274 Fuji Xerox Co., Ltd.

Claims (5)

[Claims] 1. A first pattern condition for prescribing a state of a pixel column having a predetermined length, or a second pattern condition prescribing a state of a pixel column longer than the first pattern condition. Pattern condition determining means for determining whether or not the condition is satisfied, content of the smoothing process corresponding to the first pattern condition is stored in the first area, and content of the smoothing process corresponding to the second pattern condition is stored in the second region. Storage means for storing in the area, and smoothing processing on the image data based on the content stored in the first area when the first pattern condition is satisfied and the second pattern condition is not satisfied. On the other hand, when both the first pattern condition and the second pattern condition are satisfied, the image data is smoothed based on the contents stored in the second area. The image processing apparatus characterized by comprising a smoothing means for performing processing. 2. The image data is selected from a first pattern condition that defines a state of a pixel column having a predetermined length and a second pattern condition that defines a state of a pixel column longer than the first pattern condition. Pattern condition determining means for determining whether the image data satisfies a predetermined image image condition, image image condition determining means for determining whether or not the image data satisfies a predetermined image image condition, and contents of smoothing processing corresponding to the first pattern condition. Storage means for storing the contents of the smoothing processing corresponding to the second pattern condition in the second region, and the second region if the second pattern condition is satisfied. Smoothing processing is performed on the image data based on the content stored in the image data, the first pattern condition is satisfied, and the image image condition and the second pattern condition are both satisfied. If not, the image data is smoothed based on the contents stored in the first area, while the first pattern condition and the image image condition are both satisfied and the second pattern condition is satisfied. An image processing apparatus comprising: a smoothing unit that prohibits the smoothing process when the above condition is not satisfied. 3. The image image condition determination means, and a difference number output means for outputting the number of times that the content of each pixel adjacent to each other in the main scanning direction or the sub scanning direction is different within a predetermined area of the image data. 3. The image processing apparatus according to claim 2, further comprising a comparing unit that determines that the image image condition is satisfied when the number of times exceeds a predetermined threshold value. 4. The image data is binary image data composed of black pixels and white pixels, and the image image condition determining means determines that the number of black pixels in a predetermined area of the image data is a predetermined value or more. In some cases,
The image processing apparatus according to claim 2, wherein it is determined that the image image condition is satisfied. 5. The image data is binary image data composed of black pixels and white pixels, and the image / image condition determining means determines whether a white / black state is present between adjacent pixels in the image data. The image processing apparatus according to claim 2, wherein it is determined whether the image image condition is satisfied based on the number of times of difference and the number of black pixels.