JPH11259640A - Process and method for color reducton of image and information storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color reducing processor for an image which can convert an inputted color moving picture into a color-reduced moving picture of specific colors in real time even when a CPU having low processing capability is used. SOLUTION: This is an image color reducing processor which converts a source moving picture into a color-reduced moving picture of a specific number of colors. This processor includes a 1st arithmetic part 44 which repeatedly generates a palette for generating palette data of the specific number of colors selected for the color reducing process of the next and succeeding screens from screen data of the source moving picture and a 2nd arithmetic part 40 which converts the screen data of the source moving picture into color-reduced screen data of the specific number of colors related to the previously generated palette data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image conversion processing device and method for converting and outputting a moving image into a reduced-color moving image and an information storage medium.

[0002]

2. Description of the Related Art Conventionally, many image processing apparatuses that take in a color image as a digital image and perform graphic processing on the digital image can handle only about 256 colors.

However, a digital color image captured by a digital camera, a scanner, or the like often includes color data of about 32,000 colors. Needs to be reduced to 256 color images.

Conventionally, such color reduction processing is performed by selecting palette data of a plurality of colors most suitable for expressing an image to be processed, palette data generation processing, and selecting an image to be processed from among the generated palette colors. Is performed in a two-stage process of a color reduction process of selecting a color to be converted for each pixel and reducing the color.

[0005] As a technique of such a color reduction processing, for example, JP-A-6-301773, JP-A-8-27877
No. 6 discloses this.

However, since the conventional color reduction processing targets still images, there is a problem that a moving image of a subject photographed by a digital video camera or the like cannot be converted into a color-reduced image in real time. there were.

That is, the process of generating the pallet data from the image to be processed imposes a large calculation load on the CPU. Therefore, when a normal CPU is used, 1 /
It is difficult to generate, in real time, palette data corresponding to an image of each frame that changes every 60 seconds.
Therefore, in the conventional color reduction processing technology that presupposes the creation of such pallet data for each frame, the color reduction processing for each frame cannot be performed in time, and as a result, frames are missing in the generated reduced color moving image. There is a problem that occurs.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to perform a process of converting an input color moving image to a predetermined color reduced color moving image. An object of the present invention is to provide an image color reduction processing apparatus, method, and information storage medium that can be executed in real time even when a CPU having a small capacity is used.

[0009]

SUMMARY OF THE INVENTION The present invention relates to an image color reduction processing apparatus for converting a moving image into a reduced number of color moving images of a predetermined number of colors. Pallet data generating means for repeatedly performing a pallet generating operation for generating pallet data of a predetermined number of colors selected, and screen data of the moving image,
Image conversion means for converting to a reduced number of color screen data of a predetermined number of colors associated with the previously generated palette data, and image output means for reading data of each color constituting the palette data based on the reduced color screen data, It is characterized by including.

[0010] The colors used for each image that is continuously input as a moving image are often similar colors. Therefore, pallet data created for a certain image can be used for images of several frames thereafter.

According to the present invention, screen data which is sequentially input as a moving image is generated by generating, from the screen data of the moving image, pallet data used for color reduction processing for the next and subsequent screens. The converted pallet data can be converted to reduced color image data. For this reason,
The color reduction processing of the original moving image to the color-reduced moving image can be executed in real time with a small calculation load.

Here, it is preferable that the pallet data generating means includes a pallet storing means for updating and storing the generated new pallet data, and the pallet generating operation is repeatedly performed at predetermined intervals.

Further, according to the present invention, there is provided an image color reduction processing apparatus for converting a moving image into a reduced number of color moving images of a predetermined number of colors. Pallet data generating means for repeatedly performing a pallet generating operation for generating pallet data of a predetermined number of colors; and reduced color screen data of a predetermined number of colors, wherein the screen data of the moving image is associated with the previously generated pallet data. And an image conversion means for converting the image data into an image.

Here, the image conversion means converts the color data of each pixel constituting the screen data of the original moving image into
It is preferable to convert the color data into color-reduced data of a predetermined number of colors associated with the pallet data generated earlier to generate the color-reduced image data.

The image conversion means converts the color data of each pixel constituting the screen data of the original image into color reduction data of a predetermined number of colors associated with the previously generated pallet data. It is preferable that the image forming apparatus is formed so as to include means for generating reduced color image data, and means for storing the reduced color image data.

Further, an image capturing device can be formed by using the color reduction processing device of the present invention.

That is, the image capturing device of the present invention comprises:
An imaging unit that captures an image of a subject as an M-color image as the primary moving image; and the color reduction processing device that converts the M-color reduced-color moving image into an N-color reduced-color moving image less than M colors. It is characterized by including.

This makes it possible to convert an image of a subject, which has been photographed using an image pickup means such as a digital camera, into a color-reduced image in real time and capture it.

Such an image capturing device can be applied to a game device.

That is, an image of a subject is captured as a color-reduced moving image using the image capturing device, and a game image including the captured color-reduced moving image of the captured object is generated using a game calculation means, and is displayed on a display. Should be displayed on the screen.

Thus, the image of the subject captured in real time is displayed on the game screen as a color-reduced moving image, so that a more interesting game device can be realized.

According to the present invention, there is provided an image color reduction processing method for converting a moving image into a reduced number of color moving images of a predetermined number of colors. A pallet generation step of repeatedly performing an operation of generating pallet data of a predetermined number of colors, and converting the screen data of the moving image into reduced color screen data of a predetermined number of colors associated with the pallet data generated earlier. And performing a color reduction step.

According to the present invention, there is provided a computer-readable information storage medium storing information for converting a moving image into a reduced-color moving image of a predetermined number of colors. The first information for repeatedly performing a pallet generation operation for generating pallet data of a predetermined number of colors selected for the subsequent color reduction processing, and the screen data of the original moving image are converted into the pallet data generated earlier. And second information for converting into a reduced color screen data of a predetermined number of colors associated with.

Here, the second information is obtained by converting color data of each pixel constituting the screen data of the original moving image into reduced color data of a predetermined number of colors associated with the pallet data generated earlier. It is preferable that the image is formed so as to include information for generating the color-reduced image data.

Further, in the present invention, when generating palette data from screen data of a moving image, a palette color which has fewer colors than the original image and which can provide a visual effect close to the original image is selected. Preferably, the pallet data is generated.

[0026]

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of an image color reduction apparatus applied to the present invention.

This color reduction processing device includes a processing device 20 and an image output device 30, and converts the dynamic image data 100 of about 32,000 colors input from the image input device 10 into 256 color reduced color moving image data 140 in real time. Output.

The image input device 10 may be, for example, a digital video camera for photographing a moving image of a subject as a color image of about 32,000 colors, or may be another image input device, for example, a laser disk player.

The color reduction processing apparatus according to the present embodiment performs the M-color (M is an integer) moving image data 100 input in this manner.
Can be converted and output in real time into N-color reduced color image data 140 that is smaller than that.

Hereinafter, the configuration will be described in detail.

The processing device includes a second arithmetic unit 40, a common memory 42, a first arithmetic unit 44, a pallet memory 46, a dummy pallet memory 48, and a reduced color image memory 50. Be composed.

When the moving image data 100 is sequentially input for each screen from the image input device 10, the second arithmetic unit 40 transfers the data of each screen constituting the moving image data 100 to the common memory 40. Write and store sequentially. The data of each screen written in the image memory 42 is synchronized with the raster scanning of the moving image data 100, and
Updated every second. Specifically, as shown in FIG.
The screen data is stored in the common memory 42 as 100-1, 1
00-2, 100-3... Are sequentially updated and written.

The feature of the present embodiment is that each screen data 100-
1, 100-2... Are divided into two-stage processes, and the processes of each stage are performed separately.

The first processing is performed mainly by the first arithmetic unit 44. The first arithmetic unit 44 includes a common memory 42
Examine the screen data written in
Palette color data suitable for reduction to six colors is generated, and this is written as pallet data 130 in the pallet memory 46 and stored.

In this way, the first calculation section 44 functions as pallet data generation means together with the pallet memory 46.

The pallet data 130 is the first
Is transferred from the arithmetic unit 44 to the second arithmetic unit 40, and is also written and stored in the dummy palette memory 48.

The second processing is performed mainly by the second arithmetic section 40. The second arithmetic unit 40 uses the 256-color palette data 130 that has been created one frame or more before and that is stored in the dummy palette memory 48.
Then, the screen data of the moving image 100 currently input from the image input device 100 is converted into 256-color reduced image data 110 associated with the pallet data, and this is written and stored in the reduced-color image memory 50.

In this way, the second arithmetic section 40 functions as an image conversion means together with the color-reduced image memory 50.

Here, in order to perform the two processes completely separately, the pallet memory 46 and the dummy pallet memory 48 have a dual buffer structure, and have a buffer area for storing the already created pallet data. It is sufficient to secure a buffer area for storing newly created pallet data, and to select and use them alternately.

The image output device 30 reads the palette data 13 from the palette memory 46 based on the reduced color image data 110 written in the reduced color image memory 50.
The data of each pallet color constituting 0 is read out one pixel at a time, and this is output as reduced color moving image data 140.

As described above, according to the present embodiment, it is possible to perform color reduction processing on each screen data of the moving image 100 that is sequentially input by using the already created pallet data. For this reason, even when a CPU or the like that does not have a sufficient calculation speed is used for the first and second calculation units 44 and 40, the input moving image 100 can be reduced in color in real time to 256 colors and output. it can.

In the embodiment shown in FIG. 1, the case where the dummy pallet memory 48 is used has been described as an example, but if necessary, the dummy pallet memory 4 may be used.
8 can be omitted. In this case, the second arithmetic unit 40 may generate the reduced color image data 110 with reference to the pallet data stored in the pallet memory 46.

FIG. 2 is a flowchart of a process for generating pallet data executed by the first arithmetic unit 44, and FIG. A flowchart of a process for converting into the reduced color image data 110 and storing the data in the memory 50 is shown.

The original image data 100 from the image input device 10
Are sequentially input, the first arithmetic unit 44 generates the pallet data 130 once every two frames of the original moving image data 100, and divides the data in the pallet memory 46 and the dummy pallet memory 48. Perform the update process. Here, the newly created pallet data 130 is
Instead of being used for the color reduction processing of the screen data of the frame used for the data creation, it is used for the color reduction processing of the screen data of the next two frames.

Then, the second arithmetic processing unit 40 uses the pallet data 130 generated based on the screen data of the previous frame to generate the reduced color image data 110 from the currently input screen data, and Write to and store. Since the pallet data 130 used at this time is generated at least one frame before, the screen data of each input frame can be converted to 256-color reduced color image data 110 in real time.

The details of the processing shown in FIGS. 2 and 3 will be described below.

As shown in FIG. 4A, 100-1, 1
It is assumed that screen data of each frame constituting the original image data 100 is input in the order of 00-2.

First, the first arithmetic unit 44 first proceeds to step S10
Sets the internal counter to K = 1. Then, each time the screen data of each frame written in the common memory 42 is sequentially updated (step S12), the internal counter K is incremented by one (step S1).
4).

Then, the internal counter becomes K = 2,
If it is determined that the data in the common memory 42 has been updated twice (step S16), in the next step S18, the pallet data for the next frame and the subsequent frames is displayed using the screen data of the frame currently written in the common memory 42. 130, and the generated pallet data 130 is stored in the memory 46,
48 is updated and written.

Such a series of pallet generation / update processing in steps S10 to S18 is repeatedly performed until all the color reduction processing of the moving image data 100 is completed (step S10).
20).

As a result, new pallet data 130 is updated and written into the pallet memory 46 and the dummy pallet memory 48 once every two frames as shown in FIG. 4B. Become.

For example, using the screen data 100-1,
Screen data 100-3, 100 of two screens and three screens ahead
-4 Palette data 130 used for color reduction processing
1 is generated. Further, the pallet data 130-3 for the screen data 100-5 and 100-6 is generated using the screen data 100-3. As described above, in the present embodiment, the palette data 140 used for the color reduction processing of the screen data two or more frames ahead is generated based on the currently input screen data.
It is not necessary to use a high-speed CPU for the first arithmetic unit 44 used for generating the pallet data, and the pallet data 130 can be generated with a sufficient margin.

In addition, it is highly possible that the screen data for several consecutive frames have similar color distributions. Therefore, even if the palette data 130 generated based on the screen data two frames before as in the present embodiment is used as the palette data for the color reduction processing of the screen input later, the image quality is not deteriorated. Good color reduction can be performed with almost no color reduction.

FIG. 6 shows the pallet data 13 to be generated.
An example of 0 is shown. Such pallet data 1
Reference numeral 30 denotes a screen image data for one screen written in the common memory 42, which is optimal for expressing the screen data.
This is performed by selecting 56 pallet colors and making them into table data as shown in FIG. For example, an RGB three-dimensional histogram is generated from a color distribution in an image for one screen, and 256 colors having a high frequency are selected as palette colors from the histogram, and palette data 130 as shown in FIG. 6 is generated. At this time, each palette color is designated by a number from 0 to 255, and R, G, and B luminance data are given in association with each number. Thus, by specifying the number, a predetermined palette color is specified.

FIG. 5 shows such pallet data 13.
An example of an algorithm for generating 0 is shown.

First, in step S50, a partial space sequence having the entire color space as the only element is created from one screen of image data to be processed.

Then, the loop processing of the following steps S52 to S58 is repeated until the number of partial spaces reaches 256.

That is, as shown in step S54,
For each space included in the subspace column, the number of pixels using the color included in the original image among the pixels of the original image is obtained. Then, as shown in step S56, the largest part of the obtained number of pixels is divided into two.
Such processing is repeated until the number of subspaces reaches 256.

Then, in step S60, a representative color of the subspace is determined for each subspace.

In this manner, from the image data for one screen, it is possible to generate pallet data 130 composed of 256 pallet colors optimal for expressing the image.

Then, the second arithmetic unit 40 outputs the screen data 10 of each frame sequentially input from the image input device 10.
0-1, 100-2... Are converted into 256 color-reduced image data 11 using the already generated palette data 130.
The process of converting to 0 is performed.

FIG. 3 shows this processing flow, for example, from the image input device 10 to the screen data 100-.
When 3 is input (step S30), the palette data 130- stored in the dummy palette memory 48 is read.
1 (which is pallet data created on the basis of the screen data 100-1).
-3 is converted into reduced color screen data 110 corresponding to 256 palette colors, and written and stored in the reduced color screen memory 50 (step S32). Such processing is repeated until all the color reduction processing of the moving image data 100 is completed (step S34).

Since the color reduction processing for each screen data is performed by using the already generated pallet data 130, the processing load is extremely small. Therefore, the second arithmetic unit 40 can perform such a color reduction process in real time without using a high-speed CPU.

For example, referring to FIG. 4, screen data 100-1
The reduced-color image data 110-3 and 110-4 of the screen data 100-3 and 100-4 are generated using the pallet data 130-1 created based on the screen data 100-3, and further generated based on the screen data 100-3. Pallet data 13
Using 0-3, reduced-color image data 110-5 and 110-6 of the screen data 100-5 and 100-6 are generated.

The memory 50 for the reduced color image generated in this way
The palette data numbers shown in FIG. 6 are given to the color-reduced image data 110 stored in.

Therefore, the image output device 30 outputs such reduced-color image data 11 stored in the reduced-color image memory 50.
Based on the data of each pixel of 0 (palette color number), the corresponding palette color data is read from the palette memory 46 and output as the reduced color moving image data 140 for each pixel.

In this way, the 32000-color moving image data 100 input from the image input device 10 is
It can be converted into six color reduced color moving image data 140 almost in real time and displayed on a display.

In the above-described embodiment, the case where the pallet data is updated once every two frames has been described as an example. However, the pallet data is updated once every three or more frames as necessary. You may do so. The longer the pallet update period is set, the less the load of processing for generating pallet data is. Therefore, the load of processing of the entire apparatus can be reduced. Of course, if the entire apparatus has sufficient processing capability, the pallet data may be updated for each frame.

In the above-described embodiment, since pallet data is not generated until at least two frames of data are input from the image input device 10, there is a possibility that an image in this portion may be missing. As a countermeasure, pallet data composed of pallet colors close to a distribution that can be expected for an input image is prepared in advance as initial pallet data, and until the first pallet data 130 is generated by the processing shown in FIG. Alternatively, it may be used as palette data for color reduction processing.

Further, in the above-described embodiment, the case where the processes of FIGS. 2 and 3 are respectively performed by the first arithmetic unit 44 and the second arithmetic unit 40 constituted by using dedicated CPUs and the like will be described as an example. However, if the CPU has sufficient processing capacity and processing speed, one CPU is made to exhibit the functions of the first and second arithmetic units 44 and 40 by using a technique such as time sharing. You may comprise.

Next, a specific example of a game apparatus to which the above-described color reduction processing apparatus is applied will be described.

FIG. 7 shows a front view and a side view of an image capturing device used in the game device. In this image capturing device, a unitized photographing unit 112 is mounted and fixed on the upper surface of the monitor 70 located in front of the player. The photographing unit 112 has a mirror 12 on its front surface, and a CCD for photographing a color image through a photographing hole 14 provided near the center of the mirror 12.
A camera 10a is provided.

The image of the player playing the game while watching the game screen displayed on the display 70 is captured by using the camera 10a functioning as the image input device 10, and is input to the color reduction processing device shown in FIG. . Then, as shown in FIG. 7A, the captured image of the player is displayed on the monitor 70 in real time as a 256-color reduced-color moving image that forms a part of the game screen.

FIG. 8 shows an example of a hardware configuration of a game device configured using the image capturing device shown in FIG. In the game device shown in FIG.
000, ROM 1002, RAM 1004, information recording medium 1006, sound generation IC 1008, image generation IC 101
0, I / O ports 1012, 1014, color reduction processing device 2
A color reduction IC 1300 functioning as 0 is connected to the system bus 1016 so as to be able to transmit and receive data mutually. The image generation IC 1010 has a display 1
018, a speaker 1020 is connected to the sound generation IC 1008, a control device 1022 is connected to the I / O port 1012, a communication device 1024 is connected to the I / O port, and an image is connected to the IC 1300 for color reduction processing. A capturing CCD camera 10a is connected.

The information recording medium 1006 mainly stores programs, image data and sound data for expressing objects to be displayed. In this embodiment, in addition to this,
The above-described operations shown in FIGS.
Also, a program for color reduction processing to be executed by 0 is stored. When the present invention is applied to a home game device, the information recording medium for storing the game program is C
D-ROMs, game cassettes, DVDs and the like are used. When applied to arcade game machines, ROM
In this case, the information recording medium 10 is used.
06 is the ROM 1002.

The control device 1022 is equivalent to a game controller and an operation panel, and is a device for the player to input the result of the determination made in accordance with the progress of the game to the main body of the device.

A program stored in the information recording medium 1006, a system program (such as initial information of the apparatus main body) stored in the ROM 1002, a control apparatus 1022
The CPU 1000 performs various data processing for controlling the entire apparatus in accordance with a signal or the like input by the CPU 1000. RAM1004
Is storage means used as a work area of the CPU 1000, and stores given contents of the information recording medium 1006 and the ROM 1002 or arithmetic processing of the CPU 1000. In addition, a data structure having a logical configuration (for example, a structure of object data) for realizing the present embodiment is constructed on the RAM or the information recording medium.

Further, this type of device includes a sound generation IC 100
8 and an image generating IC 1010 are provided so that a suitable output of game sounds and game images can be performed.
Sound generation IC 1008 Information recording medium 1006 and ROM 10
02 is an integrated circuit that generates game sounds such as sound effects and background music based on the information stored in 02, and the generated game sounds are output by the speaker 1020. The image generation IC 1010 includes a RAM 1004,
A so-called head-mounted display (HMD) can be used as the display 1018 based on image information sent from the ROM 1002 information recording medium 1006 or the like.

The communication device 1024 exchanges various types of information used inside the game device with the outside. The communication device 1024 is connected to another game device to transmit and receive given information according to the game program. It is used for transmitting and receiving information such as a game program via a communication line.

The various processes described with reference to FIGS. 1 to 7 include an information recording medium 1006 storing a program for performing the processes shown in the flowcharts of FIGS. 2 and 3, a CPU 1000 operating according to the program, and an image generation device. IC
1010, a sound generation IC 1008, and the like.
Note that the processing performed by the image generation IC 1010, the sound generation IC 1008, and the like may be performed by software using the CPU 1000, a general-purpose DSP, or the like.

Further, in the above-described embodiment, the case where the present invention is applied to a game device has been described as an example. However, the present invention is directed to a case where a color image of a subject captured by a variety of other devices, for example, a CCD or the like is read by a computer. It can also be applied to a case where the image is displayed in real time as a color-reduced image on the display of the above.

Further, in the above embodiment, the case where the color image of 32,000 colors is reduced to 256 colors has been described as an example. However, the present invention is not limited to this, and the color image of M colors is
The present invention can be widely applied to the case where the color reduction processing is performed on a smaller number of N color images.

[0084]

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a color reduction processing device to which the present invention is applied.

FIG. 2 is a flowchart illustrating a process for generating pallet data.

FIG. 3 is a flowchart illustrating a process for generating color-reduced image data using a color palette.

FIG. 4 is an explanatory diagram showing a relationship between input moving image data, pallet data generated thereby, and reduced-color moving image data generated using the pallet data.

FIG. 5 is a flowchart illustrating an example of an algorithm for generating pallet data.

FIG. 6 is an explanatory diagram showing an example of generated color pallet data.

FIG. 7 is an explanatory diagram illustrating an example of an image capturing device to which the present invention has been applied.

FIG. 8 is a functional block diagram illustrating an example of a game device to which the present invention has been applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 image input device 10 a camera 20 processing device 30 image output device 40 second calculation unit 42 common memory 44 first calculation unit 46 pallet memory 48 dummy pallet memory 50 reduced color image memory 100 primary image data 110 reduced color image data 130 Pallet data 140 Color-reduced moving image data

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09G 5/36 510 G09G 5/36 510M 520 520A

Claims (10)

[Claims] An image color reduction processing apparatus for converting a primary moving image into a reduced color moving image of a predetermined number of colors, wherein a predetermined number of colors selected for color reduction processing for a next screen and subsequent screens from screen data of the primary moving image. Pallet data generating means for repeatedly performing a pallet generating operation for generating the pallet data, and an image for converting the screen data of the moving image into reduced color screen data of a predetermined number of colors associated with the pallet data generated earlier. An image color reduction processing apparatus, comprising: conversion means; and image output means for reading data of each color constituting the pallet data based on the color reduction screen data. 2. The pallet data generation unit according to claim 1, wherein the pallet data generation unit includes a pallet storage unit in which generated new pallet data is updated and stored, and wherein the pallet generation operation is repeatedly performed at predetermined intervals. Characteristic image color reduction processing device. 3. An image color reduction processing apparatus for converting an original moving image into a reduced-color moving image of a predetermined number of colors, wherein the predetermined number of colors selected for the next and subsequent screens from the screen data of the original moving image. Pallet data generating means for repeatedly performing a pallet generating operation for generating the pallet data, and an image for converting the screen data of the moving image into reduced color screen data of a predetermined number of colors associated with the pallet data generated earlier. A conversion means, and an image color reduction processing device comprising: 4. The image conversion device according to claim 1, wherein the image conversion unit is configured to associate color data of each pixel constituting screen data of the original moving image with the previously generated pallet data. An image color reduction processing apparatus for converting the image data into color-reduced color data and generating the color-reduced image data. 5. The image conversion unit according to claim 1, wherein the image conversion unit associates the color data of each pixel constituting the screen data of the moving image with the previously generated pallet data. An image color reduction processing apparatus, comprising: means for converting the color-reduced color data into color-reduced color data to generate the color-reduced image data; and means for storing the color-reduced image data. 6. An image of a subject as M
6. An image pickup means for picking up an image as a color image, and the color reduction processing device according to any one of claims 1 to 5, which converts the M color-reduced moving image into N color-reduced moving images less than M colors. An image capturing device characterized by the above-mentioned. 7. A game device, comprising: the image capturing device according to claim 6; and game calculation means for generating a game screen including a color-reduced moving image of the captured subject. 8. An image color reduction processing method for converting a source image into a reduced color moving image of a predetermined number of colors, the method comprising the steps of: A palette generation step of repeatedly performing an operation of generating color palette data, and a color reduction step of converting screen data of the moving image into color reduction screen data of a predetermined number of colors associated with the previously generated palette data. A color reduction processing method for an image, comprising: 9. A computer-readable information storage medium in which information for converting a moving image into a reduced-color moving image of a predetermined number of colors is stored. First information for repeatedly performing a pallet generation operation of generating pallet data of a predetermined number of colors selected for use, and screen information of the moving image associated with the pallet data generated earlier. An information storage medium characterized by storing second information for converting into color-reduced screen data of a number of colors. 10. The color information according to claim 9, wherein the second information is a color reduction of a predetermined number of colors in which color data of each pixel constituting screen data of the original moving image is associated with the pallet data generated earlier. An information storage medium comprising information for converting data into data and generating the color-reduced image data.