JP3689673B2 - Image processing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and method for reducing an image color for display.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image processing display device that displays an image processing result such as a copying machine, a display device having a small number of display colors for an image to be displayed is generally used. In that case, color reduction processing is required to display the image processing result. The color reduction processing is performed by a method such as error diffusion with emphasis on the quality of the display result.
[0003]
In such an image processing display device, even when processing for moving the display screen, such as zooming and scrolling, conventionally, the same color reduction processing is applied to display an image on the display. That is, a color reduction processing unit that emphasizes image quality has been used.
[0004]
[Problems to be solved by the invention]
However, a color reduction processing unit that places importance on image quality, such as error diffusion, takes time. Therefore, in the conventional example in which the color reduction processing unit is applied when scrolling or zooming is repeatedly performed, the color reduction processing cannot follow the movement of the image on the display, and the scrolling or zooming is not smooth.
[0005]
It is an object of the present invention to provide an image processing apparatus and method that can eliminate such disadvantages.
[0006]
[Means for Solving the Problems]
An image processing apparatus according to the present invention includes a scaling unit that scales an image, a first color reduction processing unit, a second color reduction processing unit having a color reduction characteristic different from that of the first color reduction processing unit, and the color conversion unit. The image that has been scaled by the doubling means is reduced in color by the first color reduction processing unit during a predetermined image change operation, and the image is reduced in color by the second color reduction processing unit when the predetermined image change operation is not performed. And a control means for controlling the operation.
[0007]
The image processing method according to the present invention includes a scaling step for scaling an image, and a first color reduction process for reducing the color of the image scaled in the scaling step during a predetermined image changing operation by a first color reduction process. When the predetermined image change operation is not performed in the color reduction process step, a second color reduction process that reduces the color of the image scaled in the scaling step by a second color reduction process different from the first color reduction process. And a processing step.
[0010]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows a schematic block diagram of an embodiment of the present invention. Connected to the main arithmetic CPU 10 are a main memory 12, an error diffusion processing unit 14 for performing color reduction processing by error diffusion, a bit slice processing unit 16 for performing color reduction processing by bit slice, a zoom processing unit 18, a JPEG decoder 20, and an LCD control circuit 22. To do. A liquid crystal display (LCD) 24 is connected to the LCD control circuit 22.
[0012]
FIG. 2 shows an operation flowchart of the present embodiment for the scroll operation, and FIG. 3 shows an image example. With reference to FIGS. 2 and 3, the operation of the present embodiment during scrolling will be described.
[0013]
When scrolling is started, the CPU 10 copies the portion displayed on the LCD 24 after scrolling from the zoom image work area secured on the memory 12 to a new work area. In accordance with an instruction from the CPU 10, the JPEG decoder 20 reads JPEG compressed image data from the memory 12 (S1), and expands compressed image data to be newly displayed on the display 24 by scrolling (S2). The decompressed data is written to the memory 12.
[0014]
Next, the zoom processing unit 18 converts the expanded image into an image with a magnification to be displayed on the display 24 (S3). The zoomed image is added as a zoom image in the work area secured on the memory 12. If the scroll operation is being executed (S4), the CPU 10 instructs the bit slice processing unit 16 to reduce the color of the zoom image generated in the work area (S5). The reduced color image is written to the display work area secured in the memory 12. The LCD control circuit 22 reads the reduced color image from the display work area on the memory 12 and applies it to the LCD 24. As a result, the color-reduced image by the bit slice method is displayed on the screen of the LCD 24 (S6). Until the scroll operation is finished (S4), the processes S1 to S4, S5, and S6 are repeatedly executed.
[0015]
When the scroll operation is finished (S4), the CPU 10 causes the error diffusion processing unit 14 to perform color reduction (S7). The error diffusion processing unit 14 reads the zoom image generated by the zoom processing unit 18 from the zoom image work area on the memory 12 and executes a color reduction process (S7). The result of the color reduction process is written to the display work area on the memory 12. The LCD control circuit 22 reads the reduced color image from the display work area on the memory 12 and applies it to the LCD 24. Thereby, the image reduced by the error diffusion method is displayed on the screen of the LCD 24 (S8).
[0016]
FIG. 4 shows an example of an image format. In FIG. 4, the image before color reduction is a 24-bit image of 8 bits for each color of RGB, and the image after color reduction is an 8-bit image of R3 bits, G3 bits, and B2 bits.
[0017]
When the bit slice processing unit 16 reads 24-bit image data of 8 bits for each color of RGB from the memory 12, it extracts the upper 3 bits from the R8 bit, the upper 3 bits from the G8 bit, and the upper 2 bits from the B2 bit. Pack into bit data. Thus, an 8-bit image of R3 bits, G3 bits, and B2 bits is generated from a 24-bit image of RGB each color of 8 bits.
[0018]
Supplying program code of software for realizing the functions of the above-described embodiment to a computer in an apparatus or system connected to the various devices to operate the various devices so as to realize the functions of the above-described embodiments. In addition, the present invention includes those implemented by operating a computer (CPU or MPU) of the apparatus or system according to a stored program and operating the various devices.
[0019]
In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, the program code is stored. This storage medium constitutes the present invention. As a storage medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, and the like can be used.
[0020]
Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer. Needless to say, the program code is also included in the embodiment of the invention according to the present application even when the functions of the above-described embodiment are realized in cooperation with the above.
[0021]
Furthermore, after the supplied program code is stored in the memory of the function expansion board of the computer or the function expansion unit connected to the computer, the function expansion board or the function expansion unit is based on the instruction of the program code. Needless to say, the CPU according to the present application also includes the case where the functions of the above-described embodiments are realized by performing part or all of the actual processing.
[0022]
【The invention's effect】
As can be easily understood from the above description, according to the present invention, when the scroll operation is started in the image processing result display device, the color reduction processing of the image displayed on the display is executed by means capable of high-speed processing. The scroll result or progress can be displayed at high speed. That is, scrolling is performed smoothly. When the scroll operation is completed, the color reduction process is performed by a high quality method, so that a high quality image can be displayed.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of an embodiment of the present invention.
FIG. 2 is an operation flowchart of the embodiment.
FIG. 3 is an image example.
FIG. 4 is an example of an image format.
[Explanation of symbols]
10: Main arithmetic CPU
12: Main memory 14: Error diffusion processing unit 16: Bit slice processing unit 18: Zoom processing unit 20: JPEG decoder 22: LCD control circuit 24: Liquid crystal display (LCD)

Claims (6)

A scaling means for scaling the image;
A first color reduction processing unit;
A second color reduction processing unit having a color reduction characteristic different from that of the first color reduction processing unit;
The scaled image in the scaling means in predetermined image change operation is Genshoku the first color reduction unit, in the second color reduction process unit when not in the predetermined image change operation An image processing apparatus comprising: control means for reducing the color of the image. The image processing apparatus according to claim 1, wherein the predetermined image changing operation is scrolling. The image processing apparatus according to claim 1, wherein the first color reduction processing unit is a bit slice processing unit, and the second color reduction processing unit is an error diffusion processing unit. A scaling step for scaling the image;
During a predetermined image changing operation, a first color reduction processing step for reducing the color of the image scaled in the scaling step by the first color reduction processing;
When the predetermined image changing operation is not performed, a second color reduction processing step for reducing the color of the image scaled in the scaling step by a second color reduction process different from the first color reduction process
An image processing method comprising: The image processing method according to claim 4, wherein the predetermined image changing operation is scrolling. 6. The image processing method according to claim 4, wherein the first color reduction process is a bit slice process, and the second color reduction process is an error diffusion process.

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