JP2511966B2 - Graphic processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic processing apparatus for enlarging and reducing an image, and particularly to a graphic suitable for enlarging and reducing while interpolating coded color data. Regarding a processing device.

[Conventional technology]

Conventionally, the interpolation process for enlarging and reducing image data is
IPSJ Transactions Vol. 26, No. 5 "Various Enlargement of Binary Images /
As described in "Performance Evaluation of Reduction Method and Processing Speed Improvement Method", a method of performing interpolation processing of a binary image is known. According to the known example, the transfer source integer coordinate interval is set in the X direction and the Y direction.
Each direction is divided into four parts, and the intermediate coordinate position corresponding to the transfer destination coordinate and the interpolation data determined by the pixels of the four points around the intermediate coordinate are white or black are made into a table in advance to speed up the process. Was there.

[Problems to be solved by the invention]

The above-mentioned prior art does not consider interpolation of a color image in which one pixel is expressed by a plurality of bits, and when performing interpolation processing for enlarging or reducing a color image, it should be performed by lift wear processing such as CPU. Then, there was a problem about speeding up.

An object of the present invention is to perform interpolation processing at high speed when enlarging or reducing a character or graphic represented by color data.

[Means for solving problems]

The above-mentioned object is: first means for storing transfer source coordinates; second means for storing intermediate points obtained by dividing the transfer source coordinate interval by n in the X direction and the Y direction; and third means for storing transfer source coordinates. Means, the fourth means for reading color data from the transfer destination coordinates and binarizing the color data under predetermined conditions, and the transfer source coordinates corresponding to the transfer destination coordinates are the intermediate coordinates indicated by the second means. In this case, the pixels at four points around the intermediate coordinates are read out, binarized by the fourth means, and the binarized four-point information and the information calculated by the second means. This is achieved by providing a fifth means for tabulating information that determines which pixel of the surrounding four points should be transferred by the intermediate coordinate points.

[Action]

The binarizing function of the image data provided in the drawing processor built in the graphic processing device is a function of a mapping color register in which the user of the graphic processing device determines the value of the image data read from the frame buffer storing the image data. It is compared with the value and the result of the comparison is set to 0 or 1. 0 or 1
Stored in the table read-only memory 16
Used to calculate the address required to read the type of interpolation table.

The interpolation table is a coordinate calculation in the image editing process,
Used to select one pixel used for image data calculation from four surrounding pixels when the coordinates are located between pixels where the CRT exists. For this reason, the region surrounded by 4 pixels is divided into 4 vertically and horizontally, and 16 in total. A number that specifies the surrounding 4 pixels is assigned to the small area by dividing into 16 areas, and 1 pixel is specified from the 4 pixels by the number of the small area including the coordinates.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 shows an embodiment of the present invention. One example
The CRT or printer control system comprises a micro processor 10, a graphics processor 11, a frame buffer 12 and a video control circuit 13. The graphics processor 11 transmits and receives commands and parameters to and from the micro processor 10 via a data bus by a signal (▲ ▼) obtained by decoding an address output by a micro processor that controls an office automation device or the like. The processing of the command is executed by the drawing processor 110 built in the graphic processing device. The rendering processor 110 interprets commands and uses parameters to execute various rendering algorithms, generate memory addresses to the frame buffer, and compute image data. The frame buffer stores the image data generated by the graphic processing device. The video control circuit converts the image data into a video signal and outputs it to an image display device such as a CRT or a printer (not shown). ROM table 2
2 stores the interpolation information when the image is edited.

FIG. 2 shows a drawing processor 110 with a built-in graphic processing device 11.
Shows the configuration of. The drawing processor for executing the interpolation processing of the color image comprises an address operation unit 20, a temporary register 21, a table read only memory 22, a data operation unit 23 and a coordinate operation unit 24.

The image data read from the source image of the frame buffer is transferred to the temporary register and binarized using the data operation unit. The image data of the binarized transfer source image is transferred to the address calculation unit, and the address of the table read only memory that stores the interpolation table is calculated. In parallel with this, the coordinate operation unit calculates the shift number corresponding to the small area of the interpolation table to be referred from the coordinates located between the pixels on the CRT. The image table to be used for image data calculation with the number of the small area to be referred to is selected from the transfer source image data previously read from the frame buffer. The selected transfer source image data is transferred to the data operation unit together with the image data read from the transfer destination image of the frame buffer, and is operated. Write the calculated data to the destination image of the frame buffer.

The difference between the known monochrome interpolation table and the color interpolation table according to the present invention will be described with reference to FIG.

Pixels (P _{0 to} P ₃ ) around the monochrome interpolation table are CR
Pixels around the color interpolation table are part of a color image of red, blue, green, etc., while the part of a white monochrome image that emits light on T or does not emit light on a CRT. However, 16 types of interpolation tables
The figure shows a binarized pixel for calculating an address required when reading from a read-only memory. The numbers assigned to the small areas of the monochrome interpolation table specify black or white, while the numbers assigned to the small areas of the color interpolation table specify surrounding pixels (P _{0 to} P ₃ ). Further, the division of the small area is not limited to 16.

The storage of the color interpolation table in the table read only memory will be described with reference to FIG.

The arrangement of the small areas of the interpolation table shown in FIG.
Change as shown in FIG. 4 (b). The small area number is represented by a binary number, and the 32-bit literal
Data. The bit positions shown in FIG. 4 (c) represent those in the table read only memory. A hexadecimal representation of the interpolation table used as 32-bit literal data is as shown in FIG. 4 (d). As described above, the interpolation table is stored in the table read-only memory as 32-bit literal data.

FIG. 5 shows an example of the interpolation table. Pixels (P _{0 to} P ₃ ) around the interpolation table are binarized pixels. White pixels are pixels that are binarized and become 0, and black pixels are pixels that are binarized and become 1. There are 16 types of interpolation tables depending on the combination of binarized pixels. Moreover, the number of surrounding pixels is not limited to four, and can be expanded. The hexadecimal representation shown in FIG. 5 is 32 bit literal data to be stored in the table read only memory by the method described with reference to FIG.

The binarizing function of pixel data will be described with reference to FIG. The binarization of image data is a comparison between the image data (S) read from the frame buffer and the value of the mapping color register (MAPCL). The method of comparison is 8
There is a type, one type with a control code MAP (MAP),
specify. For example, if the map is set to "000", the image data is unconditionally binarized into 1 and 2. Also, the map "110"
Then, if the image data (S) is smaller than the value set in the mapping color register, it is binarized as 1 and if it is large, it is binarized as 0.

In the mapping color register described above, the color for which the color image is to be interpolated is set. For example, when enlarging an image in which characters are drawn in a specific color and the background is drawn in another color, specify the character color in the mapping color register and specify "001" in the map. By doing so, character interpolation can be performed. In this way, the colors to be interpolated can be arbitrarily selected by the mapping color register and MAP.

Note that the present invention, as a pixel represented by a plurality of bits,
Although the color information has been described as an example, gradation information or a mixture of color information and gradation information may be used.

〔The invention's effect〕

According to the present invention, since interpolation processing of multi-valued data such as a color image can be executed, stepwise display due to enlargement of multi-valued data such as a color image and pixel omission due to image processing such as pixel overlap and rotation due to reduction, Image quality deterioration can be prevented.

Further, the interpolation processing of the color image can be performed at high speed at the same speed as the conventional monochrome interpolation processing.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the construction of the drawing processor of FIG. 1, and FIG. 3 is a second diagram.
FIG. 4 is a diagram showing a comparison between the interpolation table stored in the table read-only memory and the known 16-division table. FIG. 4 shows the method of storing the interpolation table in FIG. 3 in the table read-only memory. FIG. 5, FIG. 5 is a diagram showing an embodiment of the interpolation table of FIG. 3, and FIG. 6 is a diagram showing an embodiment of the image data binarizing function of FIG. 11 ... Graphic processing device, 22 ... Table read only memory, 23 ... Data operation unit, 110 ... Drawing processor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakatsu Yokoyama 3-2-1, Sachimachi, Hitachi City Hitachi Engineering Co., Ltd. (72) Inventor Takashi Sone 1450, Kamimizuhonmachi, Kodaira City, Hitachi Ltd. Musashi Plant

Claims (1)

(57) [Claims] 1. A graphic processing device for storing information of a pixel unit in which one pixel is expressed by a plurality of bits, converting predetermined transfer source area data and transferring the converted data to a transfer destination area. A plurality of reference tables that store information that specifies which peripheral pixels to select for each minute area obtained by subdividing into Each time the coordinate point of is calculated, a corresponding minute area of the transfer source is calculated, the information of each pixel point around it is converted into desired binary information, and then the reference table corresponding to the combination of the surrounding points is calculated. Information is read from the reference table to specify which peripheral pixel is selected in correspondence with the minute area, and the peripheral pixel data selected by the information is used to transfer information to and from the transfer destination pixel data. Arithmetic processing Graphics processing apparatus according to claim and.