JPH04358289A - Image data processor - Google Patents

Abstract

PURPOSE:To provide an image data processor which corrects (interpolates) the omission of the image data when the image data are reduced. CONSTITUTION:When the image data are reduced down to 1/N, a data selector 10 selects the data including the image data to be reduced and the data approximate to the reduction unit of the image data. Then a comparator 4 decides the time of reduction of the image data based on the data selected by the selector 10. Thus the reduced image data are corrected (interpolated. In such a constitution, the image data can be corrected (interpolated) in a reduction mode at a high speed with use of the simple hardware and without performing any complicated logical arithmetic operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data reduction processing apparatus used to reduce image data in graphic displays, printers, facsimile machines, etc. used in computers, etc.

0002

2. Description of the Related Art FIG. 4 is a block diagram showing a schematic configuration of a conventional image data reduction processing device. What is shown in FIG. 4 is an image data reduction processing device for reducing image data to 1/4. In the figure, 1 is the first Y-axis address counter for image data, 2 is the first X-axis address counter for image data, 3 is the first bitmap memory in which the original image data to be reduced is stored, and 4 is the reduction Comparator for data to be used, 5
6 is a second Y-axis direction address counter of the second bitmap memory 5, and 7 is a second X-axis direction address counter of the second bitmap memory 5.

FIG. 5 is an explanatory diagram showing a page image of the bitmap memory shown in FIG. In the figure, 21 is image data before reduction, 22 is image data after reduction, and 23 and 24 are data patterns.

Next, the operation of the above conventional image data reduction processing apparatus will be explained. The scanning direction of the image data, which is transferred to the second bitmap memory 5 while reducing the image data existing in the first bitmap memory 3, is the X-axis direction. According to the addresses specified by the first Y-axis address counter 1 and the first X-axis address counter 2, the first bitmap memory 3 corresponds to each pixel of the second bitmap memory 5 that stores the reduced image data. Output data. This output is 16-bit data in a 4×4-bit range that performs image data reduction. This data is input to a comparator 4, and if some of the 16 bits are 1 or more (hereinafter referred to as threshold value), the bit corresponding to the reduced image data is set to 1. The reduced image data is stored on the second bitmap memory 5 at a location indicated by the second Y-axis address counter 6 and the second X-axis address counter 7. Next, the first Y-axis direction address counter 1, the first X-axis direction address counter 2, the second Y-axis direction address counter 6, and the second X-axis direction address counter 7 are sequentially counted in the scanning order of image data transfer, and the image data is continuously imaged. Data reduction is performed.

[0005]

[Problems to be Solved by the Invention] Since the above-described conventional image data reduction processing device is configured as described above, the range of data before reduction corresponding to the reduced pixel and the data input to the comparator 4 are different from each other. have the same range. For this reason, for example, when the threshold value of the comparator 4 is 6, the output will be 1 in a case like the data pattern 24 shown in FIG. Although the data is grouped together, it straddles the pixel boundary, so the threshold value, which is the criterion for judgment, is not exceeded in either area, and the output does not become 1. As a result, data loss occurs in the reduced image data. There was a problem in that the inconvenience occurred.

The present invention has been made to solve the above-mentioned problems, and provides an image data processing device that corrects (interpolates) missing data in image data when performing image data reduction processing. With the goal.

[0007]

[Means for Solving the Problems] An image data processing device according to the present invention includes a certain area or more of one area (
If there is a threshold (threshold value), the data in the adjacent image data area is also included in the judgment, and the image data is reduced.

[0008]

[Operation] The image data processing device in this invention has the following features:
In the bitmap memory, by simultaneously outputting the image data area corresponding to the reduced pixel and the image data area adjacent to this image data area for the address given to this bitmap memory,
Reduction and correction (interpolation) of image data are performed using adjacent image data areas for determination at the time of reduction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an image data processing apparatus according to an embodiment of the present invention. What is shown in FIG. 1 is an image data processing apparatus for reducing image data to 1/4. In the figure, 1 is the first Y-axis direction address counter of image data, and 8 is the first
A third Y-axis address counter that is the Y-axis address counter 1 plus 1, 2 is the first X-axis address counter for image data, and 9 is a third X-axis address counter that is the first X-axis address counter 2 plus 1. , 3 is a first bitmap memory in which the original image data to be reduced is stored, 10 is a data selector that selects the output of the first bitmap memory 3, and 4 is a comparator that compares the selected data with a threshold value. , 5 is a second bitmap memory that stores the reduced image data;
6 is a second Y-axis direction address counter of the second bitmap memory 5, and 7 is a second X-axis direction address counter of the second bitmap memory 5.

FIG. 2 is an explanatory diagram showing a page image of the bitmap memory shown in FIG. In the figure, 21 is image data before reduction, 22 is image data after reduction, and 23 is a data pattern.

FIG. 3 is an explanatory diagram showing the output for the address of the first bitmap memory in FIG. 1 and the selection bit of the data selector.

Next, the operation of the image data processing apparatus according to the embodiment of the present invention will be explained. For the first Y-axis direction address counter 1 and the first X-axis direction address counter 2, the third Y-axis direction address counter 8 and the third
The X-axis direction address counters 9 each indicate an address that is always incremented by 1 from the first Y-axis direction address counter 1 and the first X-axis direction address counter 2. The lowest bits of the addresses indicated by the direction address counter 2, the third Y-axis address counter 8, and the third X-axis address counter 9 are not given to the first bitmap memory 3, and the addresses of the upper bits except the lowest are given to the first bitmap memory 3. 1 bitmap memory 3. The first bitmap memory 3 can simultaneously output four times as much data for one reduced pixel, and as shown in FIG.
In contrast, the values of the first Y-axis address counter 1, the first X-axis address counter 2, the third Y-axis address counter 8, and the third X-axis address counter 9 are provided to the first bitmap memory 3. As a result, it is possible to obtain image data adjacent to each reduced pixel by one pixel in the X-axis direction and the Y-axis direction in the positive direction.

Next, the data selector 10 selects the original image data corresponding to the reduced one pixel, including image data adjacent to the original image data. In the case of this embodiment, image data that are adjacent to each other by one bit in the X-axis direction and the Y-axis direction are included in the selection. The data selector 10 has four data patterns (a), (b), (
It is sufficient if c) and (d) can be selected by the value of the address counter. The data selected by the data selector 10 is compared with a threshold value by the comparator 4, and it is determined whether the reduced image data should be set to 1 or 0.
The data is stored in the bitmap memory 5 at the position indicated by the second Y-axis address counter 6 and the second X-axis address counter 7. Next, the first Y-axis direction address counter 1, the first X-axis direction address counter 2, the third Y-axis direction address counter 8, the third X-axis direction address counter 9, the second Y-axis direction address counter
The axial address counter 6 and the second X-axis address counter 7 are sequentially counted and the image data is continuously reduced.

As a result, when the threshold value of the comparator 4 is set to 6 in the conventional device described above, the data pattern 23 as shown in FIG. According to the embodiment, since the judgment is made including the adjacent image data, it is possible to correct (interpolate) missing data in the image data.

In the above embodiment, the case where address counters in the Y-axis direction and the X-axis direction are used as plus 1 is explained, but an adder or the like may also be used.

Furthermore, in the above embodiment, the image data is
Although the explanation is about a processing device that reduces the image data to 1/2 or 1/3, image data can be reduced at any reduction ratio such as 1/2 or 1/3, depending on the selection conditions of the data selector 10 and the comparator 4. By changing the threshold value etc., the method of correction (interpolation) when reducing image data can be varied in various ways.

Further, in the above embodiment, the case where the reduced image data is transferred to and stored in the second bitmap memory 5 is explained, but the object to be transferred may be an image output device such as a display device or a printer. , the same effect as the above embodiment is achieved.

[0018]

As described above, according to the image data processing apparatus of the present invention, there is an area (threshold value) of 1 or more in the image data area close to the image data area to be reduced. In this case, data in the adjacent image data area is also included in the image data reduction process, so correction (interpolation) when reducing image data can be performed without performing complex logical operations. Since image data reduction processing is performed simply by comparing quantized data, it can be realized with simple hardware, high-speed processing, and memory configuration and data selector By changing the selection conditions and the threshold values of the comparator, excellent effects such as reduction and correction (interpolation) of wide image data can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an image data processing device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a page image of the bitmap memory in FIG. 1;

FIG. 3 is an explanatory diagram showing outputs for addresses of the first bitmap memory in FIG. 1 and selection bits of a data selector.

FIG. 4 is a block diagram showing a schematic configuration of a conventional image data reduction processing device.

FIG. 5 is an explanatory diagram showing a page image of the bitmap memory in FIG. 4;

[Explanation of symbols]

1 First Y-axis address counter 2 First X-axis address counter 3 First bitmap memory 4 Comparator 5 Second bitmap memory 6 Second Y-axis address counter 7 Second X-axis address counter 8 Third Y-axis address counter 9 Third X-axis direction address counter 10 Data selector 21 Image data before reduction 22 Image data after reduction 23, 24 Data pattern

Claims (1)

[Claims] Claim 1: In an image data processing device that reduces image data existing in a bitmap memory to 1/N and transfers it to another bitmap memory, display device, etc., this reduction is applied to the image data to be reduced. data selection means for selecting data including data close to the reduction unit of the image data to be reduced, and reduction determination means for determining when to reduce the image data based on the data selected by the data selection means, An image data processing device characterized by performing correction (interpolation) on reduced image data.