JPH08125847A - Image processor - Google Patents

Abstract

PURPOSE: To enlarge/reduce an image without damaging the arrangement of picture elements expressing the gray level of a binary image expressing its gray level by systematically arranging the picture elements. CONSTITUTION: This device is provided with a second data storage means 102 equipped with capacity for storing the picture elements for one lateral row or one longitudinal column of image data, repetition information extracting means 103 for extracting the repetition information showing the arrangement of picture elements from the data stored in the second data storage means 102, one-dimensional image enlarging/reducing means 104 for enlarging or reducing a one-dimensional image by inputting the repetition information outputted from the repetition information extracting means 103 and enlargement/reduction scale, and third data storage means 107 for storing the output of the one- dimensional image enlarging/reducing means 104.

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, and more particularly to an image processing apparatus for enlarging or reducing an image represented by a bit map.

[0002]

2. Description of the Related Art The conversion of an image having grayscale (halftone) into a binary image reduces the capacity of the image file in the image file system, and thus reduces the bandwidth of the transmission path in the image transmission to make it resistant to noise. Therefore, in image display, it is often used as a method for displaying on an inexpensive image display device.

The dither method is used as the image conversion method.
Among them, the method called "organized dither method" is characterized in that the hardware configuration and the processing principle are simple and the memory capacity required for processing is small. These dither methods are described in detail in Nikkei Electronics, May 1, 1978, p. 50-64.

Conventionally, in order to enlarge or reduce a bitmap image, a method of simply repeating or thinning out each pixel according to an enlargement ratio has been adopted. However, a binary image obtained by the systematic dither method has a pixel in which light and shade of the image are represented. Since the image is expressed by the arrangement method, if the image is enlarged / reduced by the conventional method, the arrangement of the pixels for expressing the gradation is broken, and the gradation of the original image cannot be expressed.

This will be described with reference to the drawings. In FIG. 3, reference numeral 301 is an original image. A black and white checkered pattern is used in order to artificially represent a halftone (gray) in the original image 301. Consider enlarging this vertically and horizontally. In the conventional simple method, each pixel is repeated in the enlargement direction according to the enlargement ratio (2 in this case). The enlarged image obtained by this is set to 302. Since the pattern itself representing the halftone is enlarged,
The checkered pattern itself is magnified, making it different from the shade of the original image.

Next, the original image 301 is halved vertically and horizontally.
Consider to reduce to. In the traditional simple way,
Pixels are thinned out in the reduction direction for each reciprocal (two in this case) of the reduction ratio (one half in this case). Reference numeral 303 is a reduced image obtained by this. Since the pixels are thinned out by skipping every pixel, the checkerboard pattern becomes entirely black (or entirely white), which is different from the shade of the original image.

Therefore, in order to compensate for such a drawback, for example, in Japanese Patent Laid-Open No. 63-98779, halftoning is used as it is for gradation processing in the enlargement / reduction processing, and binarization is first performed by a dither method or the like at the final output stage. The method of doing is adopted.

[0008]

However, in the method disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-98779, in order to enlarge / reduce the image, the binary image is multiplied by several times (the halftone quantization number is 2).
In the case of 56, halftone image data having an information amount of 8 times) must always be held, and there is a drawback that an image once converted into a binary image cannot be enlarged or reduced. Was.

The present invention has been made in view of the above-described problems, and its object is to maintain a pixel array representing a gray level in a binary image in which a gray level is represented by a systematic array of pixels. An object is to provide an image processing device capable of enlarging / reducing.

[0010]

In order to achieve the above object, an image processing apparatus according to the present invention comprises a first data storage means for storing rectangular image data, and a horizontal row or a vertical row of the image data. Second data storage means having a capacity capable of storing pixels for columns; repetition information extraction means for extracting repetition information of pixel arrangement from the data stored in the second data storage means; and the repetition information. One-dimensional image enlarging / reducing means for enlarging or reducing a one-dimensional image by inputting the repetitive information and the enlarging / reducing ratio output from the extracting means, and third data for storing the output of the one-dimensional image enlarging / reducing means. A storage means and a fourth data storage means connected to the third data storage means are provided.

An image processing apparatus according to another aspect of the present invention includes first data storage means for storing rectangular image data, and a first arbiter connected to the first data storage means.
A plurality of scaling means connected to the first arbiter by a data line and a data request line; a second arbiter connected to the scaling means by a data line and a data request line; and a second arbiter. A second data storage unit connected to the first data storage unit;
Of the image data output from the arbiter of the third data storage means having a capacity capable of storing one horizontal row or one vertical column of pixels, and pixels from the data stored in the third data storage means. Repetitive information extracting means for extracting repetitive information of the sequence, and one-dimensional image enlarging / reducing means for enlarging or reducing a one-dimensional image by inputting the repetitive information and the enlargement / reduction ratio output from the repetitive information extracting means. And a fourth data storage means for storing the output of the one-dimensional image enlarging / reducing means.

Further, it is desirable that the repetition information is composed of a pattern of pixel arrangement and the number of repetitions thereof.

[0013]

As described above, in the structure of the present invention, by providing the repetitive information extracting means for extracting the information on how the pixel columns are repeated for each column in the vertical and horizontal directions of the image, It is possible to perform enlarging / reducing on a binary image that expresses shading by a systematic arrangement, while maintaining the arrangement of pixels indicating the shading.

In another configuration of the present invention, a plurality of image enlarging / reducing units are provided and an arbiter is provided between the image enlarging / reducing unit and the image data storing unit, so that the image enlarging / reducing process can be performed at high speed. Is possible.

[0015]

【Example】

(Embodiment 1) An image processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image processing apparatus according to the first embodiment of the present invention. In FIG. 1, 101 is the first
Data storage means, and has a sufficient capacity to store a binary image to be processed. A second data storage unit 102 holds one horizontal row or one vertical column of image data output from the data storage unit 101. 10
Reference numeral 3 denotes a repetitive information extracting means, which kind of pixel arrangement is repeated or repeated for the image data for one horizontal row or one vertical column stored in the data storage means 102. Information on how many pixels are connected to the non-existing image data is extracted. Reference numeral 104 denotes a one-dimensional image enlarging / reducing means, which inputs repetitive information from the repetitive information extracting means 103 and, based on the repetitive information and the enlarging or reducing ratio 106, enlarges / reduces image data for one horizontal row or one vertical column. Perform reduction processing. Reference numeral 107 denotes a third data storage unit, which holds the enlarged or reduced image for one row or one column output from the one-dimensional image enlarging / reducing unit 104. Reference numeral 108 denotes a fourth data storage means, which has a sufficient capacity to store the enlargement / reduction processing result image.

The operation of the image processing apparatus configured as described above will be described below with reference to FIGS. 1 and 4 to 7.

First, the rectangular binary image to be processed is stored in the data storage means 101. The image data of the uppermost horizontal row of this image data is read out to the data storage means 102. The repetitive information extraction means 103 is the data storage means 1
Pixels are checked from the beginning of 02 and a variable length structure is output.

FIG. 4 is an explanatory view of the variable length structure.
In FIG. 4, reference numerals 407a and 407 indicate the entire variable length structure. Reference numerals 401 to 406 denote data fields in the structure 407. There are two kinds of structures 407 depending on whether or not the pixel rows are repeated, that is, a structure 407a in which the pixel rows are repeated and a structure 407b in which the pixel rows are not repeated.
To be distinguished. A field 401 is a field indicating whether or not a pixel column is repeated. Depending on the contents of the field 401, the subsequent fields are classified into two types. If there is repetition of the pixel row, the field 401 has a value of "1". At that time, the field 402 stores the number of times the pixel row is repeated, the field 403 contains the number of bits of the repeated pixel row, and the field 404 contains the pixel itself of the repeated pixel row.

If there is no repetition of pixel columns, field 40
It is assumed that 1 has a value of "0". At that time, the field 405 contains the number of pixels in which non-repeating pixels are consecutive, and the field 406 contains the pixels of the non-repeating pixel row.

FIG. 5 shows an example of the data storage means 102. 0 indicates a black pixel and 1 indicates a white pixel. The structure 40 output from the repetitive information extraction means 103 in the case shown in FIG.
FIG. 6 shows specific numerical values of 7.

The structure 407 is sequentially sent to the one-dimensional image enlarging / reducing means 104, and the one-dimensional image enlarging / reducing means 104 contains the contents of each field of the structure and the enlargement / reduction ratio 106.
Enlargement / reduction processing is performed from and. Structure 4 sent
If the field 401 in 07 is 1, its structure 4
Since 07 represents the repeating data, the data of the number of bits corresponding to the value stored in the field 403 is stored in the field 404. The pixel column is sequentially output to the data storage unit 107 by the number of times the product of the enlargement or reduction ratio (2 in this case) and the contents of the field 402.

When the field 401 in the transmitted structure 407 is 0, the structure 407 represents data that is not repeated, so that the data for the number of pixels indicated by the contents of the field 405 is stored. It is stored in the field 406. Enlargement / reduction ratio of 10 for that data
6 (2 in this case), the non-repetitive pixel row is enlarged / reduced using the conventional enlargement / reduction method, and the result is sequentially output to the data storage unit 107.

FIG. 7 shows a data storage means 1 corresponding to FIG.
The pixel column in 07 is shown. The above processing for the structure 407 is performed for all the pixels of the data storage unit 102. This completes the enlargement / reduction processing for the image data for one horizontal line. Enlargement / reduction processing for the image data for one horizontal line is executed from the top line to the bottom line of the image. This completes the horizontal enlargement / reduction processing of the entire image.

Next, the obtained processed image in the horizontal direction is regarded as an original image, and similar processing is performed in the vertical direction of the image as well, whereby the enlargement / reduction processing for the entire image is completed.

If the contents of the field 401 can be distinguished between the two states, generality can be achieved even if the contents are changed to values other than the above.

Further, even if the order of each field in the structure 407 is changed, generality is maintained. (Second Embodiment) An image processing apparatus according to a second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of an image processing apparatus according to the second embodiment of the present invention. In FIG. 2, 101 is the first
Data storage means, and has a sufficient capacity to store a binary image to be processed. A first arbiter 201 gives a read right to a data read request to the data storage means 101. Reference numerals 202a and 202b are enlarging / reducing means, and are the data storage means 10 shown in the first embodiment.
2, repetitive information extraction means 103, one-dimensional image enlargement / reduction means 104, enlargement or reduction ratio 106, data storage means 1
07. 203 is a second arbiter,
A write right is given to a data read request to the data storage means 101. Reference numeral 108 denotes a fourth data storage means, which has a sufficient capacity to store the enlargement / reduction processing result image.

The operation of the image processing apparatus configured as described above will be described below with reference to FIG.

First, the rectangular binary image to be processed is stored in the data storage means 101. The two enlargement / reduction units 202 make a data request to the arbiter 201 when 202 themselves are not processing. The arbiter 201 arbitrates in response to a data request from the scaling means 202 so that a plurality of scaling means 202 do not access the data storage means 101 at the same time, and data is read out to only one scaling means 202. Give the right.

The enlarging / reducing means 202 which has obtained the data read right from the data storing means 101 is the data storing means 10.
Image data for 1 horizontal row is read from 1 and enlargement / reduction processing is performed. The enlarging / reducing processing for one horizontal row is the same as the method shown in the first embodiment.

When the enlarging / reducing means 202 completes the enlarging / reducing process for the image data for one horizontal line, the arbiter 20
Data is requested to 3. The arbiter 203 arbitrates in response to a data request from the enlarging / reducing means 202 so that the plurality of enlarging / reducing means 202 do not simultaneously access the data storage means 108, and writes data to the only enlarging / reducing means 202. Give the right.

The enlarging / reducing means 202 which has acquired the right to write data into the data storing means 108 is
To write one horizontal row of image data.

This completes the enlarging / reducing process for the horizontal row of image data. Enlargement / reduction processing for the image data for one horizontal line is executed from the top line to the bottom line of the image. In this enlarging / reducing process, each line of image data is processed in parallel except for the access to the data storage unit 101 and the data storage unit 108 via the arbiter 201 and the arbiter 203. This completes the horizontal enlargement / reduction processing of the entire image.

Next, the obtained processed image in the horizontal direction is regarded as an original image, and the same process is performed in the vertical direction of the image, whereby the enlargement / reduction process for the entire image is completed.

In this embodiment, two scaling means are used for description, but if three or more scaling means are used, the parallelism is further increased and the processing speed is increased.

[0037]

As described above, the image processing apparatus of the present invention is provided with the one-dimensional pixel pattern repetitive information extracting means, and switches the processing contents depending on whether or not the pixel pattern is repeated, so that a grayscale image can be displayed. When the binarized image is enlarged or reduced,
By avoiding repetition of each pixel itself and adjusting the number of repetitions of the entire pixel array, it is possible to perform the enlargement / reduction processing of the binary image while maintaining the halftone expression faithful to the original image.

Further, by performing the scaling operation in parallel, high speed processing becomes possible.

[Brief description of drawings]

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

FIG. 2 is a block diagram of an image processing apparatus according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of problems in the conventional example.

FIG. 4 is an explanatory diagram of a variable length structure according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of data in a data storage unit 102 according to the first exemplary embodiment of the present invention.

FIG. 6 is a diagram showing an example of data of a structure 407 according to the first embodiment of the present invention.

FIG. 7 is a diagram showing an example of data in a data storage unit 107 according to the first embodiment of the present invention.

[Explanation of symbols]

 101, 102, 107, 108 Data storage means 103 Repeated information extraction means 104 One-dimensional image enlargement / reduction means 106 Enlargement / reduction ratio 201, 203 Arbiter 202 Image enlargement / reduction means 401-406 Structure field 407 Entire structure

Claims (3)

[Claims] 1. A first data storage unit for storing rectangular image data, and a second data storage unit having a capacity capable of storing pixels for one horizontal row or one vertical column of the image data, A one-dimensional image is input by inputting repetitive information extraction means for extracting repetitive information of pixel arrangement from the data stored in the second data storage means, repetitive information and enlargement / reduction ratio output from the repetitive information extraction means. A one-dimensional image enlarging / reducing means for enlarging or reducing the image, a third data storing means for storing an output of the one-dimensional image enlarging / reducing means, and a fourth data storage connected to the third data storing means. And an image processing apparatus. 2. A first data storage means for storing rectangular image data, a first arbiter connected to the first data storage means, and a connection between the first arbiter and a data line and a data request line. A plurality of scaling means, a second arbiter connected to the scaling means by a data line and a data request line, and a second data storage means connected to the second arbiter. The enlarging / reducing unit has a third data storage unit having a capacity capable of storing pixels for one horizontal row or one vertical column of the image data output from the first arbiter; and the third data storage. The iterative information extracting means for extracting the iterative information of the pixel arrangement from the data stored in the means, and the iterative information and the enlargement / reduction ratio output from the iterative information extracting means are input to enlarge or expand the one-dimensional image. The image processing apparatus according to claim the 1-dimensional image scaling means for reducing, to have a fourth data storage means for storing an output of said 1-dimensional image scaling means. 3. The repetition information comprises a pattern of pixel arrangement and the number of repetitions thereof.
The image processing device described.