JPH06333034A - Image processing method and device - Google Patents

Abstract

(57) [Summary] [Object] To provide an image processing method and apparatus capable of processing an image with high quality while suppressing image deterioration. [Constitution] When the optimum value for drawing a block to be reduced is not one, a flag for determining which one is selected is initialized (S11), and a horizontal 1 /
An n × m block corresponding to the reduction of n and 1 / m in the vertical direction is set (S12), and the average of each pixel value forming the set block is obtained (S14). Next, the average value is compared with the drawable pixel value, and it is judged whether or not there is one pixel value most suitable for representing an n × m block (S15).
If the number is not one, the flag is referred to (S17), the pixel value representing the block is determined (S18), the flag is inverted (S19), and the process is repeated for the next unprocessed block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and apparatus for processing image data created by an information processing apparatus or obtained by an image reading apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, image reduction is performed by thinning out images based on a certain rule or by performing a logical operation between adjacent pixels. As for image compression, the entire image is compressed at the same compression rate, or the compression rate is partially changed based on physical properties such as color space frequency of the image.

[0003]

However, in the above-described conventional example, the work of reducing the width of the image to 1 / n and the height to 1 / m is ultimately represented by what value of this n × m block. That is. In the method of thinning out by a certain rule, a pixel for a reduced image is selected regardless of the values of surrounding pixels, and the selected pixel may happen to be completely different from the surroundings. Further, even in the case of utilizing a logical operation, the one that most representatively represents the pixels forming the block is not always selected depending on the content of the operation. For example, when the binary data is reduced, it is possible that only one pixel in the block is different from the surrounding pixels and the representative value does not become the pixel value occupying the majority.

Further, in the case of image compression, it is 1 for humans.
Not all images are of equal importance,
For example, in a portrait, the importance of the person in the picture and that of the background are obviously different. However, if the entire image is compressed at the same compression rate, there is a problem in that both important information and unimportant information are compressed by humans with the same degree of importance. Further, even when the compression ratio is partially changed according to the physical properties of the image, the physically important information such as the brightness information is not always important to the person who views the image, and the entire image is previously There is also a problem that it is necessary to perform analysis and requires a huge amount of calculation.

The present invention was made to solve the above problems, and an object of the present invention is to provide an image processing method and apparatus capable of suppressing deterioration of an image and processing the image with high quality.

[0006]

In order to achieve the above object, the image processing apparatus of the present invention has the following configuration. That is, in an image processing apparatus that processes image data created by an information processing apparatus or obtained by an image reading apparatus or the like, setting means for setting n × m blocks for the image data, and the setting means An average value calculating means for calculating an average value of pixel values in the block and a determining means for determining a pixel value to be drawn from the average value obtained by the average value calculating means are provided, and the determined pixel value is not one. In this case, each pixel value is alternately adopted as a representative value of the block, and the obtained image data is reduced to 1 / n in the horizontal direction and 1 / m in the vertical direction.

[0007]

In such a structure, n × for image data
When the block of m is set, the average value of the pixel values in the set block is calculated, the pixel value to be drawn is determined from the obtained average value and the pixel value in the block, and the determined pixel value is not one , Each pixel value is alternately adopted as a representative value of the block, and the obtained image data is reduced to 1 / n in the horizontal direction and 1 / m in the vertical direction, thereby suppressing deterioration of the image and processing the image with high quality.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the information processing system in this embodiment. As shown in the figure, this system is composed of a CPU, a ROM, a RAM, etc., and controls a central processing unit 1, an external storage device (memory) 2 such as a hard disk device, and a CR.
A display device 3 such as T, a keyboard 4, and a pointing device 5 such as a mouse constitute a main part thereof.

<First Embodiment> FIGS. 2 and 3 are schematic views showing the concept of image reduction in the first embodiment. FIG. 2 is applied to a case where a binary image is reduced to 1/3 in both length and width. First, a 3 × 3 block is set for image data, and an average value of pixels forming the block is calculated. Then, the pixel value that can be actually drawn from that value is used as the representative value (“1” in this example) of the block. Further, FIG. 3 is applied to the case where the same number of white and black pixels are present in the block when the binary image is reduced to 1/4 in the vertical and horizontal directions.
In this case, there are two drawable pixel values that are closest to the obtained average value, "1" and "0". Therefore, in the first embodiment, based on whether or not a value larger than the obtained average value is used in the previous drawing, a value opposite to the previous value is actually used as the pixel value of the block to represent the block. It is a value.

Next, the processing procedure executed by the central processing unit 1 for the above-described image reduction will be described below with reference to the flowchart shown in FIG. First, when the optimum value for drawing the block to be reduced is not one, a flag for determining which to select is initialized (step S1).
1). Next, for the image data stored in the memory 2,
An n × m block corresponding to a reduction of 1 / n in the horizontal direction and 1 / m in the vertical direction is set (step S12). And step S1
It is determined whether or not there is a block that has not been subjected to the reduction process in the block set in 2 (step S13). As a result, No, that is, if there is no unprocessed block, the process ends. However, if Yes, that is, if there is an unprocessed block, the average of the pixel values of each block is calculated (step S14). Next, step S
The average value obtained in 14 is compared with the drawable pixel value, and n
The most suitable pixel value to represent a block of × m is 1
If the result is Yes, that is, if it is one, the pixel value is determined as the representative value of the block (step S16), and the next unprocessed block is The process from step S13 described above is repeated.

On the other hand, the determination result in step S15 is N
o, that is, when the optimum value for drawing the block to be reduced is not one, the flag for determining which is selected is referred to (step S17), and the pixel value representing the block is determined based on the result. Determine (step S1
8). Then, the flag is inverted (step S19),
For the next unprocessed block, the processing from step S13 described above is repeated.

As described above, according to the first embodiment, it is possible to suppress deterioration due to the reduction by forming the reduced image by representing the block to be reduced by the pixel value that best represents the block. Further, in the binary image, when the reduction target block has the same number of black and white pixels, all the blocks are not determined to be white or black, and the original image can be reduced faithfully.

<Second Embodiment> Next, a second embodiment of the present invention will be described in detail with reference to the drawings. The configuration of the information processing system to which the image compression method of the second embodiment is applied is the same as that of the first embodiment described above,
The description is omitted. FIG. 5 is a diagram showing a point of interest in the image (an important portion for which the compression rate is to be set low) and a screen for setting the compression rate, and FIG. 6 increases the compression rate as the distance from the point of interest increases. It is a figure which shows the screen which selects an algorithm. 7 is a diagram showing a screen for setting the size of a unit block to be compressed, and FIG. 8 is a diagram showing a screen for selecting a compression method for compressing the set block.

FIG. 9 is a diagram showing a file for storing the data set by the screens shown in FIGS. 5 to 8 and the compressed data. In FIG. 9, 91 is the size of the image (vertical × horizontal), 92 is the total number of blocks obtained from the set unit block size, and 93 is the set unit block size (vertical × horizontal). 94 is the lowest selected compression ratio (basic compression ratio) of the compression ratios set for each target point, and 95 is the relative compression ratio of each block with respect to the basic compression ratio obtained according to the selected algorithm. , 96 stores the image data obtained by compressing each block at each relative compression rate by the selected compression method.

Next, the processing procedure executed by the central processing unit 1 for the above-mentioned image compression will be described below with reference to the flowchart shown in FIG. First, as shown in FIG. 5, the attention points in the image captured in the memory 2 and displayed on the display device 3 are set using the pointing device 5 (step S21), and the attention points are set for each of the set attention points. The point compression rate is set (step S22). Next, it is determined whether or not all the attention points have been set (step S2
3) If the determination result is Yes, the lowest compression rate is selected from the compression rates of the points of interest set in step S22 and set as the basic compression rate (step S24). Then, an algorithm for increasing the compression rate each time the point is separated from the target point is set (step S25). The algorithm set in step S25 may be a method of linearly changing the compression rate with increasing distance, or a method of changing the compression rate according to a Gaussian distribution.

Next, as shown in FIGS. 7 and 8, the memory 2
An nxm block, which is a unit for compression, is set for the image data stored in (step S26),
Further, a compression method for compressing the unit block is set (step S27). The compression method set in step S27 may be a method of taking a logical sum or a method of taking a logical product in the case of simple thinning or a binary image.

After the above preparation is completed, the image stored in the memory 2 is processed. First, step S26
For each block set in step S22, the compression rate of the point of interest set in step S22 and the compression rate of the block to be processed this time according to an algorithm that increases the compression rate each time the block is separated from the point of interest set in step S25 Is determined (step S28). In addition, the ratio between the compression rate determined in step S28 and the basic compression rate selected in step S24 is calculated to obtain the relative compression rate, and the block is set in step S27. The target block is compressed (step S29). Subsequently, it is determined whether or not there are unprocessed blocks remaining (step S30). If the determination result is Yes, the process returns to step S28, and if No, the process ends.

As described above, according to the second embodiment, a portion important to humans can be set to a low compression rate, so that more information is left and the appearance is natural. Moreover, since high compression can be applied to a less important portion, if the image quality at the point of interest is the same, the data amount of the entire image becomes small. Furthermore, when changing the compression ratio of each part, it is not necessary to perform complicated calculation such as scanning the entire image to obtain physical characteristics.

<Third Embodiment> Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Conventionally,
The eraser function in image processing for processing image data created by an information processing apparatus or obtained by an image reading apparatus or the like is realized by painting a designated area with a single color such as white.

Therefore, although the problem does not occur when the background is plain, when the eraser function is applied to a region having a certain pattern such as a lattice pattern of the background, the specified region is There was a problem that it was painted with a single color regardless of the background pattern, and the original word "eraser" was different from the operation expected by the user.

The third embodiment was made in order to solve the above problems. Even if the eraser function is applied to an area where the background has a certain pattern, the surrounding area is not affected. It is an object of the present invention to provide an image processing method and apparatus capable of obtaining an image that matches a pattern with.
The configuration of the information processing system to which the eraser function of the third embodiment is applied is the same as that of the first embodiment described above, and the description thereof will be omitted.

FIG. 11 shows that when the background image displayed on the display device 3 has a certain pattern, the pointing
It is a figure which shows the state which designated the area | region to which an eraser function is applied using the device 5. FIG. 12 is a diagram showing a screen for designating an area in which a pattern (pattern) for filling the area to which the eraser function is applied exists. FIG. 13 is a diagram showing a screen for setting a rectangular area in the original image data in block units having the width and height of the extracted basic pattern.
Then, FIG. 14 is a diagram showing a pattern for filling the area to which the eraser function is applied.

Next, the processing procedure of the central processing unit 1 for realizing the above-mentioned eraser function will be described below with reference to the flowchart shown in FIG. As shown in FIG. 11, the area 11 to which the eraser function is applied is designated (step S3).
1) As shown in FIG. 12, when the area 12 in which the pattern (pattern) for filling the specified area exists is specified (step S32), the area 12 specified in step S32 is specified in step S31. A rectangular basic pattern forming an image that fills the area 11 is extracted (step S33). Here, 13 shown in FIG. 13 is an extracted basic pattern, and one of the vertices of this basic pattern 13 is defined as an origin, and the original image data is scanned (matched) based on this origin, thereby Pattern 1
An area is set in units of blocks having a width and a height of 3 (step S34). That is, each block includes one basic pattern 13 forming the background.

Next, among the blocks set in step S34, a plurality of blocks specified in step S31 and including the area 11 to which the eraser function is applied are detected (step S35). Then, each block including the area 11 to which the eraser function detected in step S35 is applied is set to the basic pattern 1 extracted in step S33.
The images respectively drawn in 3 are created in the memory 2, and the logical product of this and the area 11 to which the eraser function is applied is used to obtain an image that fills the area 11 to which the eraser function is applied, as shown in FIG. It is obtained on the memory 2 (step S36). This image is an image matched with the periphery of the area 11 designated in step S31. Finally, in the image obtained in step S36, step S3
Drawing is performed in the area 11 to which the eraser function designated by 1 is applied (step S37).

Thus, according to the third embodiment, as shown in FIG.
As shown in 6, even if the eraser function is applied to an area where the background has a pattern of a certain pattern, the designated area is not simply painted in white, but can match the surrounding pattern. Image is obtained. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device.

It goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0027]

As described above, according to the present invention, it is possible to suppress deterioration of an image and process the image with high quality.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of an information processing system according to an embodiment.

FIG. 2 is a diagram showing a case where a binary image is reduced to 1/3 in height and width in the first embodiment.

FIG. 3 is a diagram showing a case where the same number of white and black pixels are present in a block when the binary image is reduced to 1/4 in width and height in the first embodiment.

FIG. 4 is a flowchart showing reduction processing in the first embodiment.

FIG. 5 is a diagram showing a screen for designating an attention point and a compression rate in the second embodiment.

FIG. 6 is a diagram showing a screen for selecting an algorithm for determining a compression ratio in the second embodiment.

FIG. 7 is a diagram showing a screen for setting the size of a unit block in the second embodiment.

FIG. 8 is a diagram showing a screen for selecting a compression method in the second embodiment.

FIG. 9 is a diagram showing an image file that stores a compression ratio, an algorithm, a block size, etc. set in the second embodiment.

FIG. 10 is a flowchart showing a compression process in the second embodiment.

FIG. 11 is a diagram showing a state in which an area to which an eraser function is applied is designated in the third embodiment.

FIG. 12 is a diagram showing a state in which a pattern for painting a designated area is designated in the third embodiment.

FIG. 13 is a diagram showing setting of basic patterns and blocks extracted in the third embodiment.

FIG. 14 is a pattern for filling the area to which the eraser function is applied in the third embodiment.

FIG. 15 is a flowchart showing a processing procedure in a third embodiment.

FIG. 16 is a diagram showing a result of applying an eraser function in the third embodiment.

[Explanation of symbols]

 1 central processing unit 2 memory 3 display device 4 keyboard 5 pointing device

Claims (4)

[Claims] 1. An image processing method for processing image data created by an information processing device or obtained by an image reading device or the like, wherein n × m blocks are set for the image data, and pixels in the set blocks are set. Obtain the average value of the values, determine the pixel value to draw based on the obtained average value, and if the determined pixel value is not one, adopt each pixel value alternately as the representative value of the block and obtain An image processing method characterized in that image data is reduced to 1 / n in width and 1 / m in length. 2. An image processing method for processing image data created by an information processing apparatus or obtained by an image reading apparatus or the like, wherein at least one point of interest for setting a desired compression rate in an image is designated, A relative compression ratio relative to the compression ratio of the designated point of interest is determined, a compression method for performing compression at the determined relative compression ratio is selected, and n × m blocks are selected based on the determined relative compression ratio. An image processing method characterized in that a block compression rate is determined for each unit and each block is compressed. 3. An image processing method for processing image data created by an information processing apparatus or obtained by an image reading apparatus or the like, and an area to which an eraser function realized by filling a specified area with a predetermined pattern is applied. Is specified, a basic pattern is extracted from the specified area, a rectangular area is set with the block having the width and height of the extracted basic pattern as a unit, and the block that includes the eraser function among the set blocks The image processing method is characterized by detecting, and creating filled image data from each detected block and the area to which the eraser function is applied, and filling the specified area with the created image data. 4. An image processing apparatus for processing image data created by an information processing apparatus or obtained by an image reading apparatus or the like, comprising: setting means for setting n × m blocks for image data; and the setting means. An average value calculating means for calculating an average value of the pixel values in the set block and a determining means for determining a pixel value to be drawn from the average value obtained by the average value calculating means are provided, and the determined pixel value is If the number is not one, each pixel value is alternately adopted as the representative value of the block, and the obtained image data is reduced to 1 / n in the horizontal direction and 1 / m in the vertical direction.