JPH06214554A - Processing method for picture data - Google Patents

Abstract

PURPOSE:To make image density of a picture pattern obtained by enlargement/ reduction seeming to the same image density as that of the original picture pattern, concerning a processing method for picture data. CONSTITUTION:When a picture pattern is indicated with a on/off state of a dot (pixel), a image density processing section 4 obtains image density as a fractional value in which a denominator is a prime number, an unit design generation section 7 decides a unit pattern in accordance with the fractional value, a pattern generating section 3 generates the picture pattern using the unit pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data processing method, and more particularly to an image data processing for making the density of a pattern obtained by enlarging / reducing an image pattern look the same as that of the original image pattern. Regarding the method.

For example, an image pattern on the screen of a display device may be displayed, or an image pattern on the screen may be created, and this image pattern may be enlarged or reduced to obtain a final pattern. The image pattern and the final pattern must match.

[0003]

2. Description of the Related Art For example, a mesh pattern is an image pattern other than characters and ruled lines displayed on a display device. This halftone pattern is mainly used to display a so-called halftone pattern.

[0004] Shading is an image pattern widely used in word processors and the like, and displays a dot pattern overlaid on a character or the like to be emphasized. Usually, a plurality of types of shades are prepared with different densities, that is, different dot densities.

On the other hand, apart from this, in image data processing, enlarging or reducing a certain (designated) image pattern is widely performed. For example, the image pattern on the screen of the display device is enlarged / reduced to display a new pattern, or the pattern is output from a printing device or the like.

[0006]

For example, in the case of halftone dot density of 50%, the image pattern is as shown in FIG. FIG. 7 shows a shaded image pattern having a density of 50%, and shows whether each pixel (dot) takes a value of black or white for each pixel. In addition, in the figure, one circle represents one pixel (dot).

In the case of halftone dot density, the number of black dots is 50% of the total number of dots (equal to the number of white dots), and black dots and white dots are arranged alternately. It becomes a different pattern. That is, this is repeated with a certain mesh pattern as a unit (so-called tiling).

When the halftone dot image pattern having a density of 50% as shown in FIG.
As shown in (B), a striped pattern was formed, and the shaded density (50%) of the original image pattern could not be maintained. In this reduction, the area shown in FIG. 8 (A) is reduced to ½ its length and 1/4 of its width to obtain the area shown in FIG. 8 (B). In this example, the area has a size of ⅛). Further, since the vertical / horizontal length ratio of the original area is 8:12, the vertical / horizontal ratio of the new area is 4: 3.

If the density of the area shown in FIG. 8 (A) is 50%, the density of the upper left and lower right areas in FIG. 8 (B) is considerably higher than 50%, and the density of the lower left and upper right areas is It will be much thinner than 50%. Note that, in FIG. 8, the shaded density is represented by the density of diagonal lines.

Although not shown, FIG. 7 (or FIG. 8)
If the shaded area of 50% density in (A) is reduced to 1/4, in extreme cases, it may be true black (density 100%) or true white (density 0%).

Further, the same thing occurs when enlarging the image pattern. As described above, conventionally, when enlarging / reducing an image pattern, there is a problem that a pattern having a density completely different from the density of the original image pattern may be generated.

It is an object of the present invention to provide an image data processing method which makes an image pattern obtained by enlarging / reducing appear to have the same density as the original image pattern. Another object of the present invention is to provide an image data processing method capable of obtaining an image pattern whose density does not change much even if it is enlarged / reduced.

[0013]

FIG. 1 is a block diagram of the principle of the present invention, showing an image data processing apparatus according to the present invention. The image data processing device includes an input unit 1, a processing device 2 and an output unit 9. The input unit 1 inputs an instruction to generate an image pattern including a ratio of enlargement / reduction of the image pattern. The output unit 9 outputs the image pattern generated by the pattern generation unit 3 and the density of which is expressed by turning on / off dots (pixels).

The processing device 2 is provided with a pattern generator 3, a density processor 4, and a unit pattern generator 7. The pattern generation unit 3 generates an image pattern in which the density is represented by on / off of dots. The pattern generation unit 3 also enlarges / reduces the image pattern output to the output unit 9 according to the enlargement / reduction ratio to generate a new image pattern.

The density processing section 4 determines the density of the image pattern. That is, the density processing unit 4 obtains the density as a fractional value whose denominator is at least a prime number. Further, the density processing unit 4 obtains the density as a value which is at least a fractional value whose denominator is a prime number and which is close to the density of the image pattern.

The unit pattern generator 7 generates a unit pattern of an image pattern according to a fractional value. The pattern generation unit 3 uses the unit pattern to generate an image pattern or a new image pattern after enlargement / reduction.

[0017]

Operation: The image pattern output to the output unit 9 or enlargement /
The new image pattern after reduction consists of the unit pattern generated by the unit pattern generation unit 7. This unit pattern follows the fractional value determined by the density processing unit 4. The denominator of fractional values is a prime number.

For example, 50% (= 1/2) of the above-mentioned FIG.
When reducing the shaded image pattern of the density of 1/8, the fractional value is set to "3/7" as an example. In this example, the prime number "7" is used as the denominator, and the value 3/7 that is the closest to 1/2 is adopted. In this case, the unit pattern is "○ ● ○ ● ○ ● ○" as an example. This is an example in which the density (the number of black dots) is 3/7 = about 43%. Furthermore, the new image pattern after reduction is the original image pattern (see FIG. 8).
A region having a size 1/8 of the size (A) (FIG. 8B)
Size), and the unit patterns are arranged.

It is also possible to generate an intermediate image pattern by arranging the unit patterns in the area of the original image pattern, and reduce this to generate an area having a size of 1/8. .

By doing so, a new image pattern after reduction can be obtained whose density is close to the density (50%) of the original image pattern (about 43%). This also applies to enlargement. Therefore, according to the present invention, an image pattern having a density close to that of the original image pattern can be obtained even if the image pattern is enlarged / reduced, and the black and white interference fringes as shown in FIG. 8B. It is possible to prevent the occurrence of the image and obtain a uniform density image pattern.

Further, even if the above-mentioned intermediate image pattern is enlarged / reduced, its density (about 43%) is not so different from that of the original image pattern (50%). Are suitable. Therefore, according to the present invention, it is possible to obtain an image pattern whose density does not change much even if it is enlarged / reduced.

[0022]

First, the principle of the present invention will be briefly described. For simplicity, consider a black-and-white image,
The function e [p] for the dot point is

[0023]

[Equation 1]

It is defined as This basic pattern p is 1 / m
The pattern reduced to is p / m. In this case, the function for the point of the i (= px + y) dot of the pattern p / m is expressed as e [p / m] (px + y),

[0025]

[Equation 2]

It can be expressed as When the value of the 0, 1, 2, ... (P-1) th dot of the new pattern p / m is obtained according to this formula (expressed using the value of the dot of the basic pattern p),

[0027]

[Equation 3]

It is obtained as follows. According to this, the pattern p
The values of the 0, 1, 2 ... (P-1) th dots of / m are respectively the values of the 0th, m, 2m, ... (Pm-m) th dots of the basic pattern p.

The above is applied to the pattern shown in FIG. 7 which is an example of the conventional image pattern. For the sake of simplicity, consider the top row of the pattern in FIG. 7, and m = 8
And In this case, the new pattern p / m is "○○○"
Will be. On the contrary, the new pattern for the second line is "●●●". That is, interference fringes are generated.

On the other hand, equation (3) is applied to the pattern p'obtained by the present invention shown in FIG. As described above, this pattern p ′ is a fractional value with the prime number “7” as the denominator and a value “3/7” close to the density of the original pattern.
It is generated by using (side by side) a unit pattern conforming to.

In this case, if m = 8, the pattern p '/
For m, the first line is "○ ● ○", the second line is "○ ● ○",
The third line is "● ○ ●" ... That is, a pattern p ′ / m having a density close to that of the original pattern p is obtained.

Looking at the difference between the pattern p of FIG. 7 and the pattern p ′ of FIG. 2, the density of the pattern p is 1 /
2, the density of the pattern p'is 3/7. Due to this, the repeating unit of the pattern p (unit pattern) is 2
It is a dot, and that of pattern p'is 7 dots.

That is, conventionally, the unit pattern has a size of 2, 4, 8, ... Dots for reasons such as easy handling of data in a computer. Further, the value of m in the case of reduction (enlargement is the same) is usually 2, 4, 8, ...

As described above, since both have a value of 2 ⁿ , when the scaling is performed by the above-mentioned logic (the most general logic), interference occurs between the two, and as a result, the image pattern That is, black and white interference fringes completely different from the original density are generated.

The present invention has been made based on the knowledge of the present inventor as described above, and the size of the unit pattern of the image pattern is selected to a value that does not cause interference with the enlargement / reduction ratio. This is used to generate an image pattern.

Specifically, the unit pattern is 1 dot × q
When dots are used and the enlargement / reduction ratio is n / m, a value that is relatively prime to m may be selected as q. Simply, q may be a prime number. Desirably, since m is a value of 2 ⁿ in many cases, q is preferably a prime number other than 2. Further, if m is a prime number such as “7”, q cannot take the value of m.

In the present invention, q is determined and a predetermined density is realized in the unit pattern. That is, the density close to the specified density is obtained. This density is given as the ratio of the numbers of black or white dots.

According to the above example, as shown in FIG. 2, q =
When the density is 7, the density “3/7” is obtained so that the density is close to the original density of 50%. As a result, the density becomes 43%, which is close to the original value. Incidentally, "4/7" may be used, and in this case the concentration is 57%.

Here, as shown in the equation (1), if the dot is on (“1”) when black, the unit pattern of 1 × q is, for example, “○ ● ○ ● ○ ● ○”. . The arrangement of black dots in the unit pattern is preferably alternating with white dots, but the arrangement is not necessarily limited to this. The size of the unit pattern is p dots ×
It may be q dots.

By generating an image pattern with such a unit pattern, it is possible to eliminate interference between the enlargement / reduction ratio and the dot arrangement cycle. By this,
As shown in FIG. 3, a new image pattern having a density close to the original image pattern can be obtained even if the enlargement / reduction is performed.

FIGS. 3A and 3B are respectively shown in FIG.
It corresponds to (A) and (B). The area shown in FIG. 3A has the pattern shown in FIG. 2 and has a density of 43%. This is reduced to ⅛ to obtain a new pattern shown in FIG. At this time, since the pattern of FIG. 3A is according to the present invention, the pattern of FIG. 3B has a uniform density (43%) close to the original density (although it is different from the original density of 50%). Image pattern.

Therefore, according to the present invention, an image pattern (FIG. 3A) suitable for enlargement / reduction can be obtained, and a pattern having a density close to the original density ( FIG. 3B) can be obtained.

Next, examples will be described. FIG. 4 is a block diagram of the embodiment and shows an image data processing device. The operator makes a predetermined input from the input unit 1,
The processing device 2 is caused to create a desired image pattern (image data), and this is output to the output unit 9. Further, the operator causes the processing device 2 to perform enlargement / reduction of the image pattern once output to the output unit 9 by performing a predetermined input from the input unit 1, and outputs a new image pattern after this processing. The output is made to the section 9. This creation or expansion /
The present invention is applied in the reduction processing.

The output unit 9 comprises a display device such as a CRT or a liquid crystal display device. These may display a monochrome image or a color image (for example, in the RGB color system). The output unit 9
May be a black and white or color (for example, according to the CYM color system) printer or the like.

The image pattern output from the output unit 9 is a pattern in which the density is expressed by turning on / off dots (pixels). That is, the pattern is as shown in FIG. Here, for the sake of simplicity, if the image is a monochrome image, the dot on corresponds to black (●) and the dot off corresponds to white (∘). Depending on the dot on / off ratio,
The density of the image pattern is displayed. For example, if the density is 50% (corresponding to FIG. 7), the number of ON dots is 50% of the total number of dots in the area.

The image pattern output to the output unit 9 is stored in the image memory 8. The image memory 8 develops and stores the image pattern on the memory by associating 1 bit with 1 dot of the image pattern. For example, dot on corresponds to “1 (high level)” and dot off corresponds to “0 (low level)”. Note that these relationships are reversed in a black-and-white inverted image.

On the other hand, from the input section 1, the designation of the image pattern to be processed, the designation of enlargement / reduction thereof, the proportion thereof, the designation of the density of the newly obtained or original image pattern, etc. are inputted. The density is designated by the operator, in particular, by directly designating the density or by designating an area of a predetermined density prepared in advance.

When directly specifying the density, for example, the operator directly inputs a numerical value indicating the density, such as "50%". Alternatively, a plurality of areas with different densities are displayed on the menu screen (of the display device). The operator is
The density is directly specified by selecting a desired density from these areas.

Alternatively, without providing a menu screen or the like, by selecting an area displayed on the display device, the density of the area may be used as the input density. The processing device 2 includes a CPU (central processing unit) and a memory. The memory includes an image memory 8 and a main memory.
Pattern generation unit 3, density processing unit 4, and unit pattern generation unit 7
Is realized by the program and CPU existing in this memory.

The pattern generation unit 3 receives an instruction input from the input unit 1, performs processing according to the instruction, and generates an image pattern using the unit pattern generated by the unit pattern generation unit 7. , This is written in the image memory 8 and output to the output unit 9.

The pattern generation unit 3 takes out the image pattern designated as the processing target from the image memory 8 and performs the designated enlargement or reduction processing for the image pattern. At this time, the size (area size) of the new image pattern after enlargement / reduction is determined based on the size of the designated image pattern and the enlargement / reduction ratio (and direction, etc.). The unit patterns generated by the unit pattern generation unit 7 are arranged in this area. That is, this area is filled with the unit pattern.

Input data relating to the designation of the density is sent from the pattern generating section 3 to the density processing section 4. Concentration processing unit 4
In, when the direct density is designated, the density designating section 5 is activated, and when the display area is designated, the density discriminating section 6 is activated.

When the density designation unit 5 is activated in response to the density designation, the density designation unit 5 checks whether or not the designated density can be represented by a fractional value P / Q (Q is a prime number) or is represented. If not, calculate the fractional value P / Q. here,
Q corresponds to q described above. When the specified density is the fractional value P / Q, the operator may change the density to "3
/ 7 ”is entered, or the density on the menu screen is“ 3
This is when the operator has designated the "/ 7" screen.

The value of the denominator Q may be a prime number in principle, but its upper limit is limited by the output density of the output unit 9. That is, the finer the dots of the output unit 9, the larger the value Q can take. This is because even if Q is large (the area of the unit pattern is large), if the dots are fine, it looks like a single dot (black dot) to the human eye. However, if Q is increased too much, it will not be visible to human eyes as one point. Therefore, the value when the point becomes invisible is the upper limit of Q. Therefore, the upper limit of Q depends on the performance of the output unit 9 and is empirically determined. Normally, Q is "7"
To about “41”.

When the density discriminator 6 is activated in response to the designation of the display area, it checks the density of the designated display area. That is, the number of dots that are on in the area is counted, and the ratio to the number of all dots is calculated. Then, when the scaling rate R / S is specified, the density determination unit 6 sets the denominator Q of the density P / Q to be a prime with respect to the denominator S of the scaling rate R / S, and The density P / Q is calculated so that the value is close to the density.

The pattern generation unit 3 transfers the density P / Q obtained by the density processing unit 4 to the unit pattern generation unit 7 to activate it. In response to this, the unit pattern generation unit 7 generates a unit pattern using the density P / Q.

If P / Q = 3/7, for example, the pattern "○ ● ○ ● ○ ● ○" is generated. The arrangement order of the black dots does not necessarily have to be alternating with the white dots, and may be, for example, "○○○ ●●●●".

Further, as the unit pattern, an area of vertical Q dots × horizontal Q dots may be generated instead of the area of 1 × Q (1 × 7 in the above example). If P / Q = 3/7, an area of 7 dots × 7 dots is set as a unit pattern, and an area in which the number of black dots is “21 (= 3 × 7)” is generated.

The pattern generation unit 3 uses the unit pattern generated by the unit pattern generation unit 7 to generate a completely new image pattern suitable for enlargement / reduction, and a new image after enlargement / reduction of a certain image pattern. Generate a pattern.

If P / Q = 3/7 and the unit pattern is "○ ● ○ ● ○ ● ○", the image pattern shown in FIG. 2 is generated. In the pattern of FIG. 2, the unit patterns are arranged in the length direction to generate the first line, and the first line is shifted to the right by 3 dots (or 4 dots to the left) to generate the second line. It is generated by shifting the eye by 4 dots to the left (or 3 dots to the right) to generate the third line, and then repeating this.

The pattern generating section 3 writes the generated image pattern in a predetermined position of the image memory 8. This image pattern is output to the output unit 9. At the time of this output, this image pattern is output as, for example, a region having the same density as the density of the original image pattern.

Next, the pattern generation processing according to the present invention will be described. FIG. 5 shows a process when an image pattern suitable for enlargement / reduction is generated. In this case, since the existing image pattern (displayed on the display device) is not used, the density is directly input.

When the operator designates the density numerically or by selecting a desired density on the menu screen, the density designating section 5 is activated (S1). The density specifying unit 5 checks whether the specified density is a fractional value P / Q (Q is a prime number) (S2). The case of the fractional value P / Q is when the operator selects (the area of) P / Q on the menu screen. The case where the fractional numerical value is not P / Q is when the operator inputs a numerical value (for example, 50% or 1/2) or selects, for example, (the area of 50%) on the menu screen.

If it is not a fractional value P / Q, the concentration designation section 5
Calculates the fractional value P / Q close to the specified concentration (S
3). If it is a fractional value P / Q, step 3 is not executed.

After that, the unit pattern generation unit 7 determines the fractional value P / Q.
To generate a unit pattern, and the pattern generation unit 3 generates an image pattern using the unit pattern (S4).
This generation is performed by filling the area of the image pattern with a unit pattern.

This image pattern is stored in a predetermined area of the image memory 8. This image pattern is a pattern as shown in FIG. 2, for example, and is a pattern suitable for enlargement / reduction.
FIG. 6 shows a process when a certain image pattern is scaled up and down to generate a new image pattern. In this case, since the existing image pattern (displayed on the display device) is used, the density of this image pattern is used as the density.

When the operator designates a certain image pattern displayed on the display device and instructs the enlargement / reduction of the image pattern, the pattern generation section 3 determines the shape, size, etc. of the designated area,
The area is read from the image memory 8 and the density discriminating unit 6 is activated (S5).

The density discriminator 6 obtains the density of the area (S5). Further, when the operator inputs the enlargement / reduction ratio R / S (S6), the density discriminating unit 6 obtains the density P / Q whose denominator is Q which is a prime to S (S7). The concentration P / Q is
When the Q is used, the density is closest to the density of the original image pattern.

After that, the unit pattern generation unit 7 determines the fractional value P / Q.
To generate a unit pattern, and the pattern generator 3 uses the unit pattern to generate a new image pattern after scaling (S8).

This generation is performed as follows. For example,
Based on the area of the original image pattern and the enlargement / reduction rate R / S, the size and shape of the area of the new image pattern after enlargement / reduction are obtained, and this new area is filled with the unit pattern. Alternatively, the area of the original image pattern is filled with a unit pattern (the original image pattern is once converted into an intermediate image pattern of density P / Q), and then this intermediate image pattern is the same as described above. The image is enlarged / reduced in the area of the new image pattern obtained in. This enlargement / reduction may be performed by the same logic as the above-described equations (1) to (3).

The generated image pattern is stored again in a predetermined area of the image memory 8. This image pattern is, for example, a pattern as shown in FIG. 2, is an image pattern having a density that looks like the original image pattern, and is enlarged / reduced according to the enlargement / reduction ratio R / S.

The present invention has been described above with reference to the embodiments.
The present invention can be variously modified according to the gist thereof. For example,
Although the above embodiment has been described with respect to a monochrome image for simplicity, the present invention can also be applied to a color image. The color image may be based on various color systems such as RGB and CYM.

For example, for the sake of simplicity, a color image based on the RGB color system and consisting of only R (red) signals will be described. In this case, if all the dots corresponding to the R signal in a certain area are on, the density is 100%.
And looks red. If it is 50%, it looks dark pink, and if it is 25%, it looks light pink. That is, this image pattern represents a chromatic color having a certain saturation by representing the density by turning dots on / off.

Here, it is considered that the image pattern of 50% density (dark pink) is reduced (to 1/8) in the same manner as described above. If this reduction is done by conventional technology,
As explained in Fig. 8, red and white (background color of paper or screen)
Interference fringes will occur. On the other hand, according to the present invention, by setting the concentration P / Q = 3/7,
An area (1 / 8th) with a density (43%) close to the original image pattern
Area) can be obtained.

That is, an area (image pattern) of a predetermined size and shape having a predetermined color, which is output (displayed) in advance on the output unit 9 of the display device or the like, is close (substantially the same) to the predetermined color. It is possible to obtain an area (image pattern) which has a color and is uniformly represented by this color and which is obtained by enlarging or reducing the original area according to the enlargement / reduction rate. In addition, in the enlargement / reduction processing, the display device or the like (the screen thereof) can be controlled in this manner.

Although the above description is for only the R signal, the present invention can be similarly applied to the G (green) signal and the B (blue) signal. Further, by applying the present invention to each of the RGB signals, the color of an image pattern which realizes a predetermined color by expressing the density by turning on / off the dots corresponding to these signals is almost changed. It can be scaled up or down without being forced to do so.

[0077]

As described above, according to the present invention,
In the image data processing, the denominator Q of the density P / Q of the image pattern is determined to be a prime to the denominator S of the scaling ratio R / S, thereby eliminating interference fringes generated during scaling and achieving uniform density. Therefore, an image pattern suitable for enlargement / reduction can be obtained, and an image pattern having a density close to that of the original image pattern can be obtained by enlargement / reduction during enlargement / reduction.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram for explaining the present invention.

FIG. 3 is a diagram for explaining the present invention.

FIG. 4 is a configuration diagram of an embodiment.

FIG. 5 is a pattern generation processing flow.

FIG. 6 is a pattern generation processing flow.

FIG. 7 is a diagram illustrating a conventional technique.

FIG. 8 is a diagram illustrating a problem of the conventional technique.

[Explanation of symbols]

 1 Input Unit 2 Processing Device (CPU / Memory) 3 Pattern Generation Unit 4 Density Processing Unit 5 Density Designation Unit 6 Density Discrimination Unit 7 Unit Pattern Generation Unit 8 Image Memory 9 Output Unit

Claims (2)

[Claims] 1. An input unit (1) for inputting an instruction to generate an image pattern, and a pattern generation unit (3) for generating an image pattern in which pattern density is represented by turning dots on / off.
And an image data processing device including an output unit (9) for outputting an image pattern, a density processing unit (4) for determining the density, and a unit pattern generation unit (7) for generating a unit pattern of the image pattern. The density processing unit (4) obtains the density as a fractional value whose denominator is a prime number, the unit pattern generation unit (7) generates a unit pattern according to the fractional value, and the pattern generation unit (3) An image data processing method characterized in that an image pattern is generated using a unit pattern. 2. An output unit (9) for outputting an image pattern in which the density is represented by turning dots on / off, an input unit (1) for inputting an image pattern generation instruction including an enlargement / reduction ratio, and an enlargement. / The output unit (9) according to the reduction ratio
An image data processing apparatus comprising a pattern generation unit (3) for enlarging / reducing an image pattern output to a device to generate a new image pattern, and a density processing unit (4) for determining the density and an image pattern unit. A unit pattern generation unit (7) for generating a pattern is provided, and the density processing unit (4) obtains the density as a value which is at least a fractional value whose denominator is a prime number and is close to the density of the image pattern, and the unit pattern The generation unit (7) generates a unit pattern according to the fractional value, and the pattern generation unit (3) enlarges / uses the unit pattern.
An image data processing method characterized by generating a new image pattern after reduction.