JPH1078769A - Picture processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the transfer speed on a bus of extended picture data and to improve utilization efficiency of a memory. SOLUTION: A memory 12, a picture extension decoding section 13, a plotting processing section 15, data transfer control sections 131, 52 are connected to a bus 10. Compressed picture data is released and extended by a picture extension decoding section 13, extended picture data is transferred to the memory 12 by control of a data transfer control section through the bus 10, extended data stored in the memory 12 is transferred to a plotting processing section 15 by control of the data transfer control section through the bus 10, and display picture data is generated by this plotting processing section 15. An instantaneous compression section 50 compressing instantly extended picture data is provided between an output end of extended picture data of the picture extension decoding section 13 and the bus 10. An instantaneous releasing section 60 releasing compression of picture data instantly compressed is provided between an input part of the plotting processing section 15 and the bus 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention does not require high precision, such as a video game machine or a personal computer, but can be performed in response to a user input or a calculation result in a limited hardware resource. 3 in real time
The present invention relates to an image processing device suitable as a device required to display a three-dimensional object.

[0002]

2. Description of the Related Art In a home TV game machine, a personal computer, a graphic computer, or the like, image processing apparatuses for generating image data to be output to a TV receiver or a monitor receiver for display are connected to each other through a bus. A general-purpose memory, a CPU, and other arithmetic LSIs are combined, and high-speed processing is enabled by providing a dedicated rendering device between the CPU and the frame buffer as a flow of image data for rendering. .

That is, in the above image processing apparatus,
When generating an image, the CPU does not directly access the frame buffer as a display memory corresponding to the display screen, but performs geometry processing such as coordinate conversion, clipping, and light source calculation, and executes a triangle / quadrangle. A three-dimensional model is defined as a combination of basic unit figures (polygons) such as the above, and a drawing command for drawing a three-dimensional image is created. Then, the CPU sends the drawing command to the drawing device via the external bus.

[0004] The drawing command includes information such as the shape, position, orientation, color, and pattern of the polygon to be drawn. The shape, position, and orientation of a polygon are determined by the coordinates of its vertices.

In the above-described image generating apparatus, for example, when displaying a three-dimensional object, the CPU decomposes the object into a plurality of polygons, generates a drawing command corresponding to each polygon, and generates the generated drawing command. Is transferred to the drawing device via the bus. The drawing device executes the drawing command, writes display data into the frame buffer, and displays a target three-dimensional object.

[0006] At this time, in order to express the object more practically, a method called texture mapping or mip mapping is used in which a predetermined image pattern is prepared and the inside of the polygon is modified by the image pattern.

Further, a CLUT recording color conversion data
There is also widely known a method of changing a display color by converting color data of an image via a (Color Look Up Table).

[0008]

SUMMARY OF THE INVENTION Incidentally, home TVs
Operation L that constitutes a game machine or personal computer
SI has been improved in performance such as higher operating frequency and smaller circuit size without increasing cost.
The amount of general-purpose memory that can be used without increasing costs has not increased much. For this reason, in home TV game machines and personal computers, the memory capacity is a so-called bottleneck.

In particular, when texture mapping is performed using a high-quality image (pre-rendering pattern) created in advance on a high-performance workstation as a texture pattern, all patterns constituting a series of moving picture segments are stored in a memory. However, if the resolution of the texture pattern increases, the memory capacity will be reduced accordingly.

Therefore, the texture pattern is compressed and held in a memory, and the data of the compressed texture pattern is read out of the memory each time it is used, and a dedicated image decompression device (a device for decompressing the data).
And a method of decompressing and using it.

In this case, in general, the decompression decoding time is much longer than the transfer time of the display image data to the frame buffer of the drawing device, so that the image decompression device is synchronized with the drawing device. Cannot work. Therefore, so that the image decompression device and the drawing device can operate asynchronously,
The decompressed image is temporarily stored in a so-called main memory or a buffer memory such as a FIFO placed between the two devices. The data stored here is obtained by decompressing the compressed data. Therefore, the memory capacity is greatly squeezed.

Further, according to the current circuit technology, a signal can be transmitted at a very high speed inside the LSI, but it is difficult to increase the signal transfer speed between the LSIs. Especially in home appliances,
The frequency of the transfer clock on the board cannot be increased. For this reason, even if processing is performed at high speed inside the LSI, the transfer speed on the bus for transmitting the result to another LSI often becomes a bottleneck. As described above, the decompressed image data must be temporarily stored in the main memory and transferred to the drawing device again. In this case, however, all data is exchanged between the LSIs via the bus. Often, the processing speed at the stage becomes a bottleneck on the processing speed of the whole system.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an image processing apparatus which can increase the apparent transfer speed between LSIs via a bus and can improve the use efficiency of a memory. I do.

[0014]

In order to solve the above problems, an image processing apparatus according to the present invention comprises a memory, an image decompression decoding unit, and a drawing processing unit. The decompressed and decompressed image data in the decoding unit is transferred to the memory through a bus, and the decompressed image data stored in the memory is transferred to the drawing processing unit through the bus. An image processing device in which display image data is generated by a drawing processing unit, wherein the decompressed image data is instantaneously compressed between an output terminal of the decompressed image data of the image decompression decoding unit and the bus. And an decompression unit for decompressing the instantaneously compressed image data is provided between the input unit of the drawing processing unit and the bus. It is an butterfly.

In the image processing apparatus having the above configuration, the image data expanded by the image expansion decoding unit is instantaneously compressed by the instantaneous compression unit, and then transferred to the memory via the bus. At the time of transfer from the memory to the drawing processing unit, the decompressed image data that has been instantaneously compressed is decompressed in a decompression unit provided before the input unit of the drawing processing unit, and the decompressed image data obtained by the decompression is obtained. The image data is supplied to the drawing processing unit, and the drawing processing is executed.

Since the decompressed image data transferred through the bus is instantaneously compressed data, the apparent transfer speed when viewed from an LSI such as a memory, an image decompression decoding unit, or a drawing processing unit is, for example, 2. It can be twice as fast. Further, since the image data stored in the memory is compressed, the use efficiency of the memory is increased.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image processing apparatus according to the present invention will be described below with reference to a video game machine.
This will be described with reference to the drawings.

FIG. 2 shows an example of the configuration of a television game machine according to an embodiment of the present invention. This example is an example of a game machine having a three-dimensional graphics function and a moving image reproduction function. .

FIG. 3 shows the appearance of the game machine of this embodiment. The game machine of this embodiment comprises a game machine main body 1 and a control pad 2 constituting an operation input section for a user. The control pad 2 is connected to the game machine main body 1 by connecting a connector plug 4 attached to a tip of a cable 3 connected to the control pad 2 to a connector jack 5A of the game machine main body 1. . In this example, two connector jacks 5A and 5B are provided on the game machine main body 1 so that two control pads 2 can be connected to the game machine main body 1 for a so-called battle game or the like. ing.

The game machine of this example can enjoy the game by loading, for example, a CD-ROM disk 6 into the game machine body 1 as an auxiliary storage means in which a game program and image data are written.

Next, the configuration of the game machine of this example will be described with reference to FIG. The game machine of this example has a configuration including two system buses including a main bus 10 and a sub bus 20. These main buses 1
The exchange of data between 0 and the sub-bus 20 is controlled by the bus controller 30.

The main bus 10 has a main CP.
U11, main memory 12, image decompression decoding unit 1
3, a pre-processing unit 14, a drawing processing unit 15, and a main D
The MA controller 16 is connected. Drawing processing unit 1
5 is connected to a processing memory 17, and the drawing processing unit 15 includes a frame buffer (frame memory) for display data and a D / A conversion circuit. The signal is output to the video output terminal 18. Although not shown, the video output terminal 18 is connected to, for example, a CRT display as a display device.

The sub bus 20 has a sub CPU 21, a sub memory 22, a boot ROM 23, a sub DMA controller 24, an audio processor 25, an input unit 26, an auxiliary storage unit 27, and an extension The communication interface unit 28 is connected. Auxiliary storage unit 27
In this example, the CD-ROM decoder 41 and the CD-RO
An M driver 42 is provided. The boot ROM 23 stores a program for starting up the game machine. Further, the audio processing memory 25M is connected to the audio processing processor 25. The audio processor 25 includes a D / A conversion circuit, and outputs an analog audio signal to the audio output terminal 29.
Output to

The auxiliary storage unit 27 stores the CD-R
CD-ROM disk 6 loaded in OM driver 42
The application program (for example, a game program) and data recorded in the application are decoded. CD-
For example, a discrete cosine transform (DC
Image data of moving images and still images compressed by the MPEG2 method using T) and image data of texture images for modifying polygons are also recorded. Also, C
The application program on the D-ROM disk 6 includes a polygon drawing command.

The input section 26 includes the control pad 2 as the operation input means described above, a video signal input terminal, and an audio signal input terminal.

The main CPU 11 manages and controls each unit on the main bus 10 side. Also, this main CP
U11 performs a part of the processing when the object is drawn as a group of many polygons. The main CPU 11 creates, on the main memory 12, a drawing command sequence for generating a drawing image for one screen, as will be described later. Main CP
Data exchange between the U11 and the main bus 10 is performed in packet units by converting data into a packet format, thereby enabling burst transfer.

The main memory 12 has a memory area for compressed image data and a memory area for decompressed image data subjected to decompression processing for image data of moving images and still images. The main memory 12 has a memory area for graphics data such as a drawing instruction sequence (this is called a packet buffer). This packet buffer is used to set a drawing command sequence by the main CPU 11 and
It is used for transferring the drawing instruction sequence to the drawing processing unit.

The image decompression decoding unit 13 includes a CD-ROM
The expansion processing of the compressed moving image data reproduced from the disk 6 and transferred to the main memory and the compressed texture pattern data on the main memory 12 is performed. In this example, since the image compression method of MPEG2 is adopted, As a matter of course, it has a decoder configuration corresponding to it.

As will be described later, the output stage of the image decompression decoding unit 13 can perform reversible compression / decompression instantaneously, that is, almost in real time, and a compression ratio of, for example, 1
An instantaneous compression section 50 of about ４ to １ ／ is provided.
In addition, the image decompression decoding unit 13 of this example uses, as an output format of the output image data, a first output data format (hereinafter, the first output data format) for requantizing and outputting the value of each pixel of the image data. Format is referred to as a direct color format), and a second method of converting each of the pixels into index data indicating a color similar to the color of the pixel among a predetermined limited number of reproduced colors and outputting the index data. An output data format (hereinafter, this second output data format is referred to as an index color format) can be selected in conformity with the processing in the drawing processing unit 15.

The drawing processor 15 executes a drawing command transferred from the main memory 12 and writes the result into the frame memory. The image data read from the frame memory is supplied to a video output terminal 1 via a D / A converter.
8 and displayed on the screen of the image monitor device.

Note that the drawing processing unit 15 is provided in the main memory 1
If the output format of the image data received from 2 is an index color format, a process of converting each pixel data from the index data to the corresponding representative color data is performed. For this purpose, the drawing processing unit 15 converts the index data and the representative color data into a CLUT (C
color Look Up Table).

The pre-processing section 14 has a configuration of a processor having a CPU, and can share a part of the processing of the main CPU 11. For example, the pre-processing unit 14 may also perform a process of converting polygon data into two-dimensional coordinate data for display.

In this example, an instantaneous decompression unit 60 for decompressing the instantaneous compression by the instantaneous compression unit 50 is provided between the preprocessing unit 14 and the main bus.

Next, the basic processing of this game machine will be briefly described below.

[Fetching of Data from Auxiliary Storage Unit 27] When the game machine in the example of FIG. 2 is powered on and the CD-ROM disk 6 is loaded into the game machine body 1, the game stored in the boot ROM 23 is played. A program for performing a so-called initialization process for execution is executed by the sub CPU 21. Then, the data recorded on the CD-ROM disk 6 is captured as follows.

That is, in the auxiliary storage unit 27, the compressed image data, the drawing command, and the program executed by the main CPU 11 are stored in the CD-ROM disk 6.
CD-ROM driver 42, CD-ROM decoder 41
, And are temporarily loaded into the sub memory 22 by the sub DMA controller 24.

The data fetched into the sub memory 22 is transferred to the main memory 12 by the sub DMA controller and bus controller 30, and further by the main DMA controller 16. The sub CP
U21 is configured to directly access the frame of the drawing processing unit 15, and the sub CPU
The change of the display image content is also performed by the drawing processing unit 15.
Is possible apart from the control.

[Expansion and transfer of compressed image data] FIG.
FIG. 3 is a block diagram for explaining in more detail mainly the flow of image data in the block diagram of FIG. In FIG. 1, dotted arrows indicate the flow of image data.

As shown in FIG. 1, the image decompression decoding unit 1
3 is, in this example, the DMA controller 131 and the FI
The FO memory 132 and an MPEG decoder (hereinafter, MD)
An EC 133, a packer 134, a FIFO memory 135, and an instantaneous compression unit 50. Instantaneous compression unit 5
0 is a conversion table 52 for performing instantaneous compression,
A controller 51.

The DMA controllers 131 and 51 are:
Arbitration of the main bus 10 is performed, and the compressed image data and the decompressed image data (instantaneously compressed) are transferred between the main memory 12 and the image decompression decode 13 while the main bus 10 is idle. It is for transferring. The FIFO memory 132 and the FIFO memory 135 are buffers with a minimum number of stages for preventing data from being lost even when a plurality of bus requests collide.

The MDEC 133 decompresses and decodes data compressed according to the MPEG2 system. This decompression decoding processing will be described by taking the case of texture pattern data as an example.

Before explaining the decompression decoding, how the data of the texture pattern is compressed will be described.

In this example, the texture pattern data is a two-dimensional image in which the pixel data of each of the red (R), green (G), and blue (B) components is 8 bits. At this time, the pixel assigned to (R, G, B) = (0, 0, 0) is interpreted as a transparent color.

First, the texture pattern is divided into a rectangular area of 16 × 16 pixels as shown in FIG. This rectangular area is called a macro block. Thereafter, the texture pattern is processed on a macroblock basis. Macroblocks whose pixel values are all transparent are removed and packed in advance. At the same time, a table indicating macroblock position information is recorded in the header, which is additional information.

As shown in FIG.
The primary color signal expression is converted into an expression composed of a luminance signal and a color difference signal. This is hereinafter referred to as CSC (Color S)
space conversion).
As shown in FIG. 4, the macro block composed of the luminance components is divided into four, and is composed of four luminance blocks Y0, Y1, Y2, and Y3 each having an area of 8 × 8 pixels. In addition, the macroblock composed of the color difference signal components is composed of two color difference signal blocks in which four adjacent pixels are grouped into a block of 8 pixels × 8 pixels. Thus, the macroblock is divided into a total of six blocks.

The DCT (D
iscrite Cosine Transforma
) is applied. DCT is a kind of similarity transformation generally called orthogonal transformation. Considering a matrix X of 8 × 8 pixels having each luminance value of a block as a component, DCT
Using a matrix P and its inverse matrix Pi, refers to a transformation defined in the form of Y = P · X · Pi. The coefficients of the DCT matrix P are as shown in Table 1 shown in FIG.

The DCT-transformed block is quantized at a different resolution for each component. A table that specifies the quantization width (step) for each component is called a quantization table (Q table). An example of the quantization table is shown in Table 2 of FIG.

In actual quantization, the value of the Q table corresponding to each component is replaced by a value QUAN that determines the overall quantization step.
This is done by dividing by the product of T.

Here, the entire quantization step QUANT
When the value of is increased, the image quality after decoding deteriorates, but the number of 0 components in the block increases, so that the compression ratio can be improved.

After the quantized blocks are numbered one-dimensionally in an order called zigzag order, variable-length coding by Huffman coding is performed. At the same time,
In this example, a 16 × 16 × 1 bit α pattern (mask pattern) in which the bit corresponding to the transparent color becomes 1 for each macroblock is prepared.

The result obtained in a macroblock unit is the final compressed image format, which is called a bit stream. That is, the continuation of a set of data and a mask pattern in units of macroblocks is 64 pixels ×
The data is texture pattern data for 64 pixels, which is recorded on the CD-ROM 6. The CD-ROM further includes a table indicating the above-described macroblock position information as the texture pattern data.
It is recorded in the header as described above.

The procedure of image expansion decoding is performed by following the reverse of the above-described image compression procedure. Since the compression in this case is irreversible, the decoding is performed using a mask pattern that is interleaved and recorded in the pixel value compressed data so that the transparent color pixels of the decompressed macroblock are correctly decoded. Pixels with a corresponding mask pattern bit of 1 are forcibly changed to a transparent color regardless of the pixel value of the decoding result.

The MDEC 133 is constituted by the following processing. (1) The compressed image and additional information (geometry information and the like) are interleaved and recorded on the CD-ROM 6. These pieces of information are continuously read out by the CD-ROM driver 42 and the CD-ROM decoder 41, and once stored in the main memory 12, only the compressed image information is cut out as described above. hand,
The data is transferred to the image decompression decoding unit 13. The additional information is processed in the CPU 11, whereby the position information of the object whose decompressed image is used as the texture is calculated. (2) The MDEC 133 includes a variable length decoder and decodes a Huffman-coded block. The Huffman tree at this time is fixed, but the value of the corresponding code can be changed. (3) The MDEC 133 also includes an inverse quantizer.
This inverse quantizer performs inverse quantization on the decoded block, and converts the block order according to the above-described zigzag order. Inverse quantization is performed in different steps for each coefficient unit of the block. (4) The inverse DCT converter included in the MDEC 133 is 8 ×
The inverse orthogonal transform of eight pixels is performed. (5) The MDEC 133 further includes a CSC processing unit,
The macroblock image represented by the luminance signal / color difference signal is converted into an image represented by three primary color signals R, G, and B. An example of the conversion is shown in Table 3 in FIG.

As described above, of the input data transferred from the auxiliary storage unit 27 to the main memory 12, the compressed image data is transferred from the main memory 12 to the image decompression decoding unit 13 by the DMA controller 131.
In the MDEC 133, a decoding process corresponding to MPEG2 is performed, and the compressed image data is decompressed, and each pixel is decoded as the direct color format image data including the three primary color signals R, G, and B as described above. .

This image data is supplied to the packer 134. The packer 134 packs the image data that has been decompressed and decoded in a format compatible with the drawing processing unit 15 on a pixel-by-pixel basis. That is, as described above, in this example, the output format of the image data to be sent to the drawing processing unit 15 can be one of the direct color format and the index color format. Step 134 is performed.

The packer 134 has a configuration as shown in FIG. That is, the packer 134 performs dither processing based on the dither matrix table 72 and vector quantization for converting pixel data into a representative color prepared in the CLUT 74 in order to convert the pixel data into the index color format. And a pack processing unit 75.

When outputting in the direct color format and the number of bits of the input pixel is equal to the number of bits of the output pixel, the dither processing section 71 and the vector quantizer 73 are bypassed, and the decoded data is packed. 75
Are packed and output in pixel units.

Even in the case of outputting in the direct color format, when the bit number N of the output pixel is smaller than the bit number of the input pixel, the dither processing section 71 performs an appropriate rounding process. In this case, MDEC 133
Can obtain decoded data in a 16-bit signed fixed-point format, and the rounding process is one of the following. a) After the clipping process is performed so that the input pixel falls within the range of N bits, the lower N bits of the integer part of the input pixel value are output. b) The upper N + 1 bits of the input pixel are rounded off and the upper N bits are output. c) After the input pixel is multiplied by the ordered dither of the fixed dither matrix table 72, the upper N + 1 bits are rounded off and the upper N bits are output.

Next, when outputting in the index color format, vector quantization using a pixel value (pixel color data) preset in the CLUT 74 as a representative point is performed in the vector quantizer 73. Instead of each pixel value, the data of the index of the corresponding representative point is output.

That is, FIG. 9 shows an example of the CLUT 74, which is an example in the case where there are 256 representative colors. That is, 256 color data 0 to color data 255 are selected in advance as possible colors of the image, and the CLUT
74, and an index is given as a color number of each color data.

As a method of vector quantization, for example,
Pixel value after decompression decoding (for each color component of the three primary colors R, G, B, for example, color data consisting of 8 bits)
And 16 to 256 types of representative color data (each of the three primary colors R, G, and B, for example, composed of 8 bits) provided as the CLUT 74, and
In the UT 74, the index of the color data having the closest color is output instead of the pixel value.

In this case, two colors (R1, G1, B1)
(R2, G2, B2) is calculated by the following formula, for example.

D = (R1-R2) * (R1-R2) + (G1-G2) * (G1-G2) + (B1-B2) * (B1-B2) (Q1) In this equation (Q1) , * Indicate multiplication.

As described above, in the index color method, the 24-bit pixel value after decompression decoding is compression-converted into 8-bit index data and output.

As described above, the pixel data packed by the packer 134 is sent to the instantaneous compression section 50 through the FIFO memory 135, and the image data is instantaneously compressed.
The instantaneous compression here differs from high-efficiency compression such as MPEG2 in that the compression ratio is low, such as 1/4 to 1/2, but is compressed / decoded reversibly at high speed by a compression / decoding circuit with a small hardware scale. What can be used is used.

In this example, run-length encoding and Huffman encoding are performed simultaneously for compression. A conversion table 52 which is a codebook as a dictionary for the compression is provided in the instantaneous compression unit 50. The conversion table 52, which is a codebook, is generated and held in advance.

As shown in the figure, the instantaneous compression section 50 functionally includes a DMA controller 51 and uses a conversion table 52 to simultaneously perform run-length encoding and Huffman encoding to instantaneously compress the data while simultaneously performing MPEG expansion decoding. The transferred image data is transferred to the main memory 12. More than,
This is the operation of the image decompression decoding unit 13.

When performing motion compensation, instantaneous lossless compression in the instantaneous compression section 50 is not performed. In this case, when reading the bit stream, the image decompression decoding unit 13 simultaneously reads and processes the image data of the previous frame expanded on the main memory 12.

When a predetermined amount of unit data called macroblocks of the expanded image data is stored in the main memory 12, the main CPU 11 transmits the expanded data to the instantaneous decompression unit 60 and the preprocessing unit 60 via the main bus 10. The data is transferred to the frame buffer of the drawing processing unit 15 via the unit 14. At this time, if the decompressed image data is transferred to the image memory area of the frame buffer, it is displayed on the image monitor as a background moving image. If the image data is transferred to the texture area of the frame buffer, the image data of this texture area is used as a texture image for modifying the polygon.

The instantaneous decompression unit 60 comprises a DMA controller 61 as a functional block and a conversion table 62 for performing a reverse conversion of the conversion table 52 of the instantaneous compression unit 50. Image data is decompressed using the conversion table 62 and the MPE
The image data is G-decompressed and decoded and sent to the drawing processing unit 15 through the preprocessing unit 14.

In the case of this example, when the output format is the direct color format, the preprocessing unit 14 outputs an image composed of three primary color signals of R, G, and B having a specified number of bits of data for each pixel. The data is supplied to the drawing processing unit 15, and the drawing processing is executed.

On the other hand, in the case of the index color format, the drawing processing section 15 is supplied with the above-described index data. As described above, the drawing processing unit 15
Has a CLUT similar to the above-described CLUT 74, performs processing for converting image data in index color format into corresponding representative color data, and restores the image data. Then, a rendering process is executed using the restored image data.

[Processing and Transfer of Drawing Instruction Sequence] The polygons forming the surface of the object are drawn in order from the polygon located deeper in the depth direction in accordance with Z data which is three-dimensional depth information. An image can be stereoscopically displayed on the two-dimensional image display surface. Main CPU1
1 creates, on the main memory 12, a drawing command sequence for causing the drawing processing unit 15 to perform drawing in order from the polygon located at a deep position in the depth direction.

The main CPU 11 calculates the movement of the object and the viewpoint based on the user's operation input from the control pad of the input unit 26, and creates a polygon drawing instruction sequence on the main memory 12.

When the drawing command sequence is completed, the main DM
The AC 16 transfers the drawing command from the main memory 12 to the drawing processing unit 15 through the preprocessing unit 14 for each drawing command.

The drawing processing section 15 sequentially executes the transmitted data and stores the result in the drawing area of the frame memory. At the time of rendering the polygon, the data is sent to the gradient calculation unit of the rendering processing unit 15, and the gradient is calculated. The gradient calculation is a calculation for calculating the inclination of the plane of the mapping data when filling the inside of the polygon with the mapping data by polygon drawing. In the case of texture, polygons are filled with texture image data,
In the case of Gouraud shading, polygons are filled with luminance values.

Furthermore, the texture of a moving image is possible.
That is, in the case of the moving image texture, the compressed moving image data from the CD-ROM disk 6 is once read into the main memory 12 as described above. Then, the compressed image data is sent to the image expansion decoding unit 13. The image data is expanded by the image expansion decoding unit 13.

Then, as described above, the decompressed moving image data is sent to the texture area on the frame memory of the drawing processing unit 15. Since the texture area is provided in the frame buffer of the drawing processing unit 15, the texture pattern itself can be rewritten for each frame. As described above, when a moving image is sent to the texture area, the texture is dynamically rewritten and changed every frame. If texture mapping to polygons is performed using the moving image in the texture area, the texture of the moving image is realized.

As described above, according to this embodiment, the decompressed image data is instantaneously compressed and
Through the main memory. Therefore, the use efficiency of the memory is improved by the amount of compression. In addition, when the output format of the decompressed image data is the index color format, the pixel data is composed of index data, so that the data amount is reduced and the use efficiency of the main memory is improved accordingly.

The expanded image data transferred from the image expansion decoding unit 13 to the main memory 12 through the main bus 10 and the expanded image data transferred from the main memory 12 to the main bus 10
The decompressed image data transferred to the drawing processing unit 15 through the process is data that is instantaneously compressed, and the amount of data is small, so that the bus transfer speed is improved.

In this embodiment, even if the format of the input compressed image data is one type, the output format of the output data from the image decompression decoding unit 13 is either the direct color format or the index color format. It is possible to select, and it is not necessary to prepare input image data separately to obtain different output formats.
The use efficiency of the main memory is improved.

Even in the case of the direct color format, the number of bits suitable for the processing in the drawing processing section 15 can be rounded by dither processing, so that output data of a desired number of bits can be easily obtained. .

In the above example, the image processing apparatus according to the present invention is applied to a game machine. However, it goes without saying that the image processing apparatus according to the present invention can be used for various purposes.

[0084]

As described above, according to the present invention, the apparent transfer speed of decompressed image data transferred on the bus is improved, and the amount of decompressed image data stored in the memory is reduced. Memory efficiency can be improved.

Also, since only one type of compressed image data is required regardless of the plurality of output formats of the decompressed image data,
There is no need to store a plurality of compressed image data for a plurality of output formats in a memory, and this also has the effect of improving memory efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a processing portion of image data in an embodiment of an image processing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a game machine as an embodiment of an image processing device according to the present invention.

FIG. 3 is a diagram showing an example of an appearance of the game machine in the example of FIG. 2;

FIG. 4 is a diagram for explaining a processing unit of compressed image data according to the embodiment of the present invention;

FIG. 5 is a diagram for explaining a compression method of compressed image data according to the embodiment of the present invention.

FIG. 6 is a diagram for explaining a compression method of compressed image data according to an embodiment of the present invention.

FIG. 7 is a diagram for explaining a compression method of compressed image data according to an embodiment of the present invention.

FIG. 8 is a block diagram showing a detailed example of some blocks in FIG. 1;

FIG. 9 is a diagram for explaining an index color format.

[Explanation of symbols]

10: Main bus, 11: Main CPU, 12: Main memory, 13: Image decompression decoding unit, 14: Preprocessing unit,
15 drawing unit, 16 main DMA controller
50: Instantaneous compression unit, 51: Conversion table for instantaneous compression,
60: Instantaneous decompression unit, 61: Conversion table for compression / decompression,
71 dither processing unit, 72 dither matrix table, 73 vector quantizer, 74 CLUT, 75
Pack processing units, 132 and 135 ... FIFO memories,
133: MPEG decoder, 134: Packer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H04N 1/41 G06F 15/66 A 7/24 H04N 7/13 Z

Claims (4)

[Claims] 1. An image processing apparatus comprising: a memory, an image decompression decoding unit, and a drawing processing unit, wherein compressed image data is decompressed and decompressed by the image decompression decoding unit, and the decompressed image data is transmitted to the data transfer control unit. The image is transferred to the memory via a bus under control of the unit, and the decompressed image data stored in the memory is transferred to the drawing processing unit via the bus, and the display processing unit generates display image data. A processing device, comprising: between the output end of the decompressed image data of the image decompression decoding unit and the bus, an instantaneous compression unit that instantaneously compresses the decompressed image data; A decompressing unit for decompressing the instantaneously compressed image data is provided between the input unit and the bus. 2. A first output data format for requantizing and outputting a value of each pixel of the decompressed image data when transferring the decompressed image data to the memory; A second output data format, which is converted into index data indicating a color similar to the color of the pixel among a predetermined limited number of reproduced colors and is output, can be selected. The image processing device according to claim 1. 3. The image processing apparatus according to claim 2, wherein
When the first output data format is selected, quantization means for requantizing the value of each pixel of the decompressed image data using a dither method is provided on the output side of the image decompression decoding unit. An image processing apparatus characterized in that: 4. The image processing apparatus according to claim 2, wherein
When the second output data format is selected, quantization means for vector-quantizing the decompressed image data in accordance with the predetermined number of reproduction colors is provided on the output side of the image decompression decoding unit. An image processing apparatus, comprising: