JPH11339013A - Image processor and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the display speed of a JPEG(joint photographic experts group) image. SOLUTION: A compressed data storing part 2 stores compressed YUV (luminance, blue, and red) data constituting a JPEG image, and a data expanding part 3 expands the compressed YUV data, and obtains the extended YUV data. A table storing part 5 stores a color classification table for dividing a displayable color and an RGB(read, green, blue) table for dividing each color classification based on RGB data. A data editing part 4 decides the color classification based on the expanded UV data in the expanded YUV data, and decides RGB data from the RGB table of the color classification based on the expanded Y data in the expanded YUV data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image processing apparatus and an image processing method, and more particularly, to an image processing apparatus and an image processing method capable of displaying or printing a JPEG image.

[0002]

2. Description of the Related Art Generally, information of a color image is represented by R (red), G (green), and B (blue) data, while a JPEG (Joint Photographic Expert Group) image is compressed by Y (luminance) U (blue) ) V (red) data. Therefore, when displaying or printing a JPEG image, the YUV data is decompressed and the RG
Processing for converting to B data is required.

Conventionally, the image processing shown in FIG.
Displays a PEG image. In step S1, the YUV data is expanded to obtain expanded YUV data. Step S2
In step 2, RGB data is obtained from the expanded YUV data based on the following equation. R = Y + 1.4020 × (V−128) G = Y−0.3441 × (U−128) −0.7139 × (V−128) B = Y + 1.7718 × (U−128) −0.7139 × (V−128) Step In S33, a color reduction process is performed on the RGB data. The color reduction process is a process for obtaining the closest color from the RGB data because, for example, a 256-color image display device can display only 256 colors.

In step S4, display data is generated from the RGB data, and the display data is displayed on a display or the like. Actually, steps S1 to S4
Is repeated for each dot (for example, 640 × 480 dots).

[0005]

Conventionally, when displaying a JPEG image, RGB data is not converted from decompressed YUV data.
Data is calculated, and the closest color that can be displayed on the display device is calculated from the RGB data. However, the calculation of the RGB data and the calculation of the closest color that can be displayed take a long time, and there is a problem that the display speed of the JPEG image is significantly reduced.

[0006]

In order to solve the above problems, the present invention provides a color type table for dividing a displayable color into a plurality of color types and an R type for dividing each color type based on RGB data.
A storage means for storing a GB table; and when given expanded YUV data obtained by expanding compressed image data, a color based on the color type table using the expanded UV data in the expanded YUV data. Color type determining means for determining a type; and RGB based on an RGB table for the determined color type using the expanded Y data in the expanded YUV data.
An image processing apparatus comprising: an RGB data determination unit that determines data.

In the above image processing apparatus, the color type is determined with reference to the color type table, and the RGB type is determined with reference to the RGB table.
Since the data is determined, there is no need to calculate the RGB data or the closest color that can be displayed by calculation.
The display speed of the G image can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this. FIG. 1 is a block diagram functionally showing an image processing apparatus according to an embodiment of the present invention.

The image processing apparatus 100 includes a compressed data storage unit 2 (flash memory) for storing compressed YUV data constituting a JPEG image, and the compressed Y
A data decompression unit 3 (JPEGLsi) for decompressing UV data to obtain decompressed YUV data, a table storage unit 5 for storing a color type table C and an RGB table P described later, the decompressed YUV data, the color type table, and RGB Data editing unit 4 (VRA) that generates display data based on the table
M), a display data storage section 6 (frame memory) for storing the display data in a format that can be displayed on the display section 7, and a control section 1 for controlling the operation of each section. The above components are connected by a bus 8.

FIG. 2 is a block diagram showing the image processing apparatus 100 in terms of hardware. This image processing apparatus 100
A CPU 81 that controls the entire apparatus based on a program stored in a ROM 82 or a hard disk 84;
ROM 82 for storing an operating system, programs, data, etc., RAM 83 used as a work area for CPU 81, hard disk 84 for storing data, programs, color type table C, RGB table P, etc., and a display for displaying JPEG images 8
5, a keyboard 86 having keys for giving operation instructions and inputting characters (including numbers and symbols);
It has a mouse 87 for giving an operation instruction and pointing out a place on the display 85, a printer 88 for printing a JPEG image in color, and a bus 80 for connecting each of the above parts.

The CPU 81 has functions as the control unit 1, the data decompression unit 3, and the data editing unit 4 in FIG. The hard disk 84 has functions as the compressed data storage unit 2, the table storage unit 5, and the display data storage unit 6 in FIG. Also, the display 85
It has a function as the display unit 7 in FIG. When the power of the image processing apparatus 100 is turned on, the palette (256 colors)
Is set to RGB data. At this time, 1) the colors used are limited even in the case of a full-color image. 2) Expression colors, such as human skin, are finely divided into expression colors. 3) A color without expression such as an object limits the expression color (for example, even if the color is red, R = 25)
Since the difference between 5 and R = 254 cannot be distinguished by the human eye, they can be treated as the same color.)

FIG. 3 shows a color type table for dividing a displayable color into a plurality of color types. Here, for convenience of explanation, it is assumed that 256 colors can be displayed. In this color type table C, colors 10 to 31 (light yellow to light yellow) are a yellow palette, colors 32 to 74 (light blue to light blue) are a blue palette, and colors 75 to 117 (light red to pale). Red) is a red palette, colors 118 to 188 (light to pale) are flesh color palettes, colors 189 to 210 (light green to pale green) are green palette, colors 211 to 232 (light gray to pale). Pale gray) is a gray (light) palette, color 233 to color 25
4 is divided into a gray (dark) system palette.

The color type is determined on the basis of the color type table C using the expanded UV data in the expanded YUV data. FIG.
8 shows an RGB table P of a green pallet. For example, if the value of the decompressed Y data in the decompressed YUV data is [0]
~ [45], the pallet number is 189 and RG
The B data has R = 36, G = 52, and B = 8.

The image processing apparatus 100 executes the image processing shown in the flowchart of FIG. 5 to display a JPEG image. In step S1, the data decompression unit 3 decompresses the YUV data in the compressed data storage unit 2 to obtain decompressed YUV data. In step S2, the data editing unit 4 determines RGB data from the decompressed YUV data based on the RGB data determination process shown in FIG.

In step S4, display data is generated from the RGB data, and the display data is
5 is displayed. Actually, steps S1 to S4
Is repeated for each dot (for example, 640 × 480 dots). Next, the RGB of FIG.
The data determination processing will be described.

In step V1, it is determined whether or not the expanded UV data in the expanded YUV data satisfies the condition (U <110 & V <126). When the expanded UV data meets the condition (U
If <110 & V <126) is satisfied, the process proceeds to step V2; otherwise, the process proceeds to step V3. Step V2
In this example, the color type is a green palette, and the palette number is determined based on the value of the extended Y data in the extended YUV data from the RGB table P of the green palette shown in FIG. For example, if the value of the decompressed Y data is [10], the pallet number is 189. This pallet number 18
9 corresponds to RGB data of R = 36, G = 52 and B = 8.

In step V3, it is determined whether or not the expanded UV data in the expanded YUV data satisfies the condition (UV ≧ 20). When the expanded UV data meets the condition (U−V ≧ 2)
If 0) is satisfied, the process proceeds to step V4. If not, the process proceeds to step V5. In step V4, the color type is set to the blue palette, and the palette number is determined from the RGB table (not shown) of the blue palette based on the value of the expanded Y data in the expanded YUV data.

At step V5, it is determined whether or not the expanded UV data in the expanded YUV data satisfies the condition (VU ≧ 65 & U ≦ 60). When the expanded UV data meets the condition (V
If (−U ≧ 65 & U ≦ 60) is satisfied, the process proceeds to step V6. If not, the process proceeds to step V7. Step V6
In this example, the color type is a yellow palette, and a palette number is determined from an RGB table (not shown) of the yellow palette based on the value of the expanded Y data in the expanded YUV data.

At step V7, it is determined whether or not the expanded UV data in the expanded YUV data satisfies the condition (VU ≧ 95). When the expanded UV data meets the condition (V−U ≧ 9)
If 5) is satisfied, the process proceeds to step V8, and if not, the process proceeds to step V9. In step V8, the color type is set to the red palette, and the palette number is determined from the RGB table (not shown) of the red palette based on the value of the expanded Y data in the expanded YUV data.

In step V9, it is determined whether or not the expanded UV data in the expanded YUV data satisfies a condition (VU ≧ 30). When the expanded UV data meets the condition (V−U ≧ 3)
If 0) is satisfied, the process proceeds to step V10, and if not, the process proceeds to step V11. In step V10, the color type is set to the flesh color palette, and the palette number is determined from the RGB table (not shown) of the flesh color palette based on the value of the expanded Y data in the expanded YUV data.

In step V11, it is determined whether or not the expanded UV data in the expanded YUV data satisfies a condition (VU ≧ 10). When the expanded UV data meets the condition (V−U ≧ 1)
If 0) is satisfied, the process proceeds to step V12. If not, the process proceeds to step V13. In step V12, the color type is set to a gray (light) -based palette, and based on the value of the expanded Y data in the expanded YUV data,
A pallet number is determined from a GB table (not shown).

In step V13, the color type is gray (dark)
A palette number is determined from an RGB table (not shown) of a gray (dark) palette based on the value of the extension Y data in the extension YUV data. The determined pallet number is, as shown in FIG.
(VRAM). The pallet number is
Since it corresponds to the RGB data, if the pallet number can be determined, the RGB data can be determined.

In step S4, display data is generated from the determined RGB data, and the display data is displayed on the display 85 as shown in FIG. here,
An image based on the determined RGB data is displayed on the display 85.
However, an image based on the RGB data may be printed on the printer 88.

In the image processing apparatus 100, the extended YUV
The color type can be determined based on the expanded UV data in the data, and then the RGB data can be derived based on the expanded Y data in the expanded YUV data. For this reason, it is not necessary to perform calculation for obtaining RGB data or calculation for reducing the color of RGB data, and the display speed of a JPEG image is improved. The image processing device 100 can be used, for example, as a rear display device of an automatic transaction device or as a general personal computer.

[0025]

As described above, in the image processing apparatus according to the present invention, a color type table for dividing a displayable color into a plurality of color types and an RGB for dividing each color type based on RGB data are provided.
A storage means for storing a table and a color type based on the color type table using expanded UV data in the expanded YUV data when expanded YUV data obtained by expanding the compressed image data is provided. Color type determining means for determining
RGB data determining means for determining RGB data based on an RGB table for the determined color type using the expanded Y data in the expanded YUV data. For this reason, it is not necessary to perform calculation for obtaining RGB data or calculation for reducing the color of RGB data, and the display speed of a JPEG image is improved.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing the image processing apparatus of FIG. 1 in terms of sentence hardware.

FIG. 3 is an illustration of a color type table.

FIG. 4 is an exemplary diagram of an RGB table.

FIG. 5 is a flowchart of image processing in the image processing apparatus of the present invention.

FIG. 6 is a flowchart of RGB data determination processing in the image processing apparatus of the present invention.

FIG. 7 is an explanatory diagram of display of RGB data.

FIG. 8 is a flowchart of image processing in a conventional image processing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 image processing device 1 control unit 2 compressed data storage unit 3 data decompression unit 4 data editing unit 5 table storage unit 6 display data storage unit 7 display unit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kazuyuki Ohashi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (4)

[Claims] 1. A color type table for dividing a displayable color into a plurality of color types, and an R for dividing each color type based on RGB data.
Storage means for storing a GB table; and when given expanded YUV data obtained by expanding compressed image data, expanded UV in the expanded YUV data
Color type determining means for determining a color type based on the color type table using data; and determining RGB data based on an RGB table for the determined color type using expanded Y data in the expanded YUV data. An image processing apparatus comprising: RGB data determination means. 2. The method according to claim 1, wherein the determined RGB values are different from each other.
An image processing apparatus comprising: display means for converting data into display data and displaying an image based on the display data. 3. The image processing apparatus according to claim 1, further comprising a printing unit configured to convert the determined RGB data into print data and print an image based on the print data. 4. A color type table for dividing a displayable color into a plurality of color types, and an R for dividing each color type based on RGB data.
A GB table, and when given expanded YUV data obtained by expanding compressed image data,
The color type is determined based on the color type table using the expanded UV data in the UV data, and the RGB data is determined based on the RGB table for the determined color type using the expanded Y data in the expanded YUV data. An image processing method comprising: