JPH07182505A - Image rotating device for printing - Google Patents

Abstract

PURPOSE:To provide the image rotating device for printing which can perform the rotating processing of image data for printing at high speed. CONSTITUTION:An external storage device 10 is provided with an area 10a storing the image data of a processing object and an area 10b to store image data after the rotating processing. These storage areas 10a and 10b are respectively set as virtual storage areas. On the other hand, a computer 9 performs the inverse transformation of affine transformation to coordinates corresponding to pixel data inside the storage area 10b and calculates the coordinates of those pixel data before the rotation. Then, the pixel data in the storage area 10a corresponding to those coordinates are read out and those pixel data are stored in the correspondent position of the storage area 10b. The computer performs this processing concerning all the pixel data in the storage area 10b, and the image data after the rotating processing are stored in the storage area 10b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing image rotating device for rotating a printing image by a set angle.

[0002]

2. Description of the Related Art Image rotation processing for printing is known in which a small computer such as a workstation (WS) is used to perform coordinate conversion of image data for printing and rotate the image data.

FIG. 4 is an explanatory diagram of this rotation processing. In this figure, 1 is a small computer such as a workstation, and 1a is a control unit including a main storage device. An external storage device 2 such as a hard disk has a storage area 2a for storing image data to be processed and a storage area 2b for storing image data after rotation processing. Here, the print image to be processed is composed of a plurality of pixels, and each pixel has different coordinates. Each pixel (pixel data) is stored in the storage area 2a corresponding to those coordinates. Similarly, each pixel data is stored in the storage area 2b corresponding to the coordinates. A set of pixel data is called image data.

In the above structure, since the capacity of the main storage device of the control unit 1a is smaller than the data amount of the image data to be processed, it is not possible to rotate the entire image at once on the main storage device. . Therefore, the image data generated after the rotation process is divided into blocks of a size that can be processed by the main storage device, and the rotation process is performed for each block.
Therefore, the storage area 2b is divided into a plurality of blocks.

For example, assume that the block 2c of the storage area 2b is selected. The coordinates of the pixels at the four corners of this block are
Coordinates are converted in the control unit 1a, and the corresponding block 2d in the storage area 2a is calculated. This calculation is obtained by the inverse transformation of the affine transformation (described later).

Next, the block 2d is read and a rotation process is performed. FIG. 5 is an explanatory diagram of this rotation processing, in which 5 is an image to be processed and 6 is an image after the rotation processing. The affine transformation shown in the following equations (1) and (2) is used for the rotation (angle θ) of this image. X = xcosθ−ysinθ (1) Y = xsinθ + ycosθ (2)

By this affine transformation, coordinates (x,
The pixel of y) is rotated counterclockwise with respect to the horizontal axis by an angle θ and becomes a coordinate (X, Y). As a result, all the pixels of the processed image 5 (FIG. 5) are rotated by the angle θ to become the processed image 6. For example, the coordinates A, B, C, and D of the pixels at the four corners of the processing target image 5 are coordinates A ′, B ′, C ′, and D ′.
Is converted to. Further, when the image 6 is subjected to the inverse transformation (angle θ) of the affine transformation described above, the image 5 is obtained. That is, the angle θ is rotated clockwise by the inverse transformation. In the actual processing, the pixel before rotation corresponding to each pixel after rotation is obtained by the inverse transformation of the affine transformation. This is because it is not possible to generate the entire area 6 after the rotation from the area 5 before the rotation. That is, a gap is generated in the rotated image from the coordinate value obtained by rounding the value obtained by the affine transformation.

Next, the image 1b after rotation processing (FIG. 4) is written in a predetermined area 2c of the external storage device 2. At this time,
It is necessary to perform a position control process in which the output blocks are combined into one as a rotated image on the hard disk. The above processing is performed for all blocks in the storage area 2b, and the image data after the rotation processing is completed in the storage area 2b.

In the above rotation processing, the affine transformation for obtaining the size of the image after rotation is performed once in order to control the position where each block is fitted, and the image before rotation necessary for each divided block after rotation is obtained. The inverse transformation of the affine transformation for obtaining the region of is performed a number of times, and the inverse transformation of the affine transformation for generating an actual rotated image is performed "the number of pixels included in the block × the number of blocks" times.

[0010]

By the way, in the above-described conventional image rotation device, the storage area 2 after the rotation processing is performed.
Since b must be divided into a plurality of blocks and rotation processing must be performed for each block, the block (for example, 2
The area (2d) of the unprocessed image corresponding to c) must be calculated. Alternatively, it is necessary to add position information for finally joining each block as an image after one rotation processing and control this also. As a result, there has been a problem that it takes a long processing time to rotate the printing image.

The present invention has been made under such a background, and an object of the present invention is to provide a printing image rotation device capable of performing rotation processing of image data at high speed.

[0012]

According to the present invention, in a printing image rotating apparatus for rotating a printing image composed of a plurality of pixels by a specific angle, each pixel data before rotation is stored at a position corresponding to the coordinates of the pixel. A first storage unit for calculating a storage capacity required when all of the pixel data are rotated by the specific angle; and a storage capacity obtained by the first calculation unit. The second storage means, the second calculation means for obtaining each pixel data of the first storage means corresponding to each storage position of the second storage means, and each pixel data of the first storage means. Pixel data transfer means for sequentially reading and writing to the storage position of the second storage means obtained from the calculation result of the second calculation means.

[0013]

According to the above structure, the first arithmetic means determines the storage capacity of the second storage means for storing the pixel data after the rotation processing, and the second arithmetic means operates as the second storage means. The rotation position is determined because the storage position of the first storage means corresponding to the storage position is determined and the pixel data transfer means copies the pixel data stored in the first storage means to the second storage means according to the correspondence. Can be simplified and the number of times of processing can be reduced.

[0014]

DETAILED 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 the arrangement of a printing image rotating apparatus according to an embodiment of the present invention. In this figure, 8 is a display for displaying a print image. An external storage device 10 such as a hard disk stores image data and the like. A small computer 9 such as a workstation has a CPU 9a and a main storage device 9b therein. The computer 9 controls the display 8 and the external storage device 10 while rotating the print image.

2 and 3 are explanatory views of this rotation processing. In these drawings, 10a is an area in which image data to be processed is stored, and 10b is image data after rotation processing. Area. These storage areas 1
Reference numerals 0a and 10b are parts of the storage area of the external storage device 10, and are set as virtual storage areas. Therefore, the CPU 9a writes / writes to the main memory 9b.
These storage areas 10a and 10b can be accessed in the same manner as reading. As a result, the pixel data can be stored / read out for each pixel data instead of in a block. Also,
The storage positions of the image data in the areas 10a and 10b correspond to the coordinates of each pixel data.

The operation of this embodiment having the above configuration will be described. First, the computer 9 transforms the coordinates E, F, G, H of the four corners of the unprocessed image data (reference numeral 10a in FIG. 2) by affine transformation, and the four transformed coordinates (E ′, F ′, A rectangle (reference numeral 10b in FIG. 2) contacting G ', H') is obtained. Then, the storage capacity of the image data after the rotation processing is determined from the area of the rectangle, and the storage area 10b is secured as a virtual storage area in the storage area of the external storage device 10 based on the storage capacity.

At this time, if the storage area 10b cannot be secured, it is found before the rotation processing that the free area of the external storage device 10 does not have the capacity necessary to generate the rotated image. As described above, there is no annoyance that it cannot be determined whether or not the rotation is possible unless the rotation process is actually performed for each block.

Next, the computer 9 performs the inverse affine transformation on the coordinates of each pixel corresponding to the storage area 10b. As a result, the coordinates of each pixel corresponding to the storage area 10b before the rotation processing are obtained. For example, storage area 1
The coordinates of the pixel 10c (FIG. 3) stored in 0b are converted into the coordinates of the pixel 10d stored in the storage area 10a.

The computer 9 reads out the pixel data corresponding to the converted coordinates from the storage area 10a and writes the pixel data in the corresponding position of the storage area 10b.

The inverse conversion of the affine transformation and the transfer of the pixel data are performed for all the pixels in the storage area 10b, and finally the image data after the rotation processing is stored in the storage area 10b.
Completed in b. Then, the computer 9 displays the image data on the display 8.

In the above image rotation processing, the affine transformation may be performed once and the inverse transformation may be performed only for the number of pixels of the rotated image, and the number of transformation processing is reduced as compared with the conventional rotation processing.

Although the hard disk is used as the external storage device in the embodiment described above, a storage device such as a magnetic tape or a magneto-optical disk (MO) may be used.

Although a workstation is used as the small computer in the embodiment, a personal computer or the like may be used.

[0024]

As described above, according to the present invention, it is possible to reduce the number of times of the coordinate conversion processing of pixel data performed in the image rotation processing, and to shorten the time required for the rotation processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a printing image rotation device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram (1) of a rotation process performed by the printing image rotation device in FIG.

FIG. 3 is an explanatory diagram (2) of a rotation process performed by the printing image rotation device of FIG. 1.

FIG. 4 is an explanatory diagram (1) of a rotation process performed by a conventional printing image rotation device.

FIG. 5 is an explanatory diagram (2) of a rotation process performed by a conventional printing image rotation device.

[Explanation of Codes] 8 Display 9 Small Computer 10 External Storage Device 10a Storage Area for Image Data Before Processing 10b Storage Area for Image Data After Processing

Claims (1)

[Claims] 1. A printing image rotating device for rotating a printing image composed of a plurality of pixels by a specific angle, comprising: first storage means for storing each pixel data before rotation at a position corresponding to the coordinates of the pixel. First computing means for computing a memory capacity required when all of the pixel data are rotated by the specific angle; second memory means having a memory capacity obtained by the first computing means; Second arithmetic means for obtaining each pixel data of the first storage means corresponding to each storage position of the second storage means, and each pixel data of the first storage means are sequentially read out to perform the second arithmetic operation. And a pixel data transfer unit for writing to a storage position of the second storage unit obtained from a calculation result of the unit, the printing image rotating device.