JPH07311568A - Method and device for outputting image - Google Patents

Abstract

PURPOSE:To provide a method and a device for image outputting which can output high quality images with high resolution while using a small capacity frame memory. CONSTITUTION:A CPU 1 writes the image data stored in a ROM 2 or that obtained by computing the data in the ROM 2 using a program stored in the ROM 2 into a frame memory 6. In this case, the image data is composed of length value and color data. The image data written into the frame memory 6 is converted into an image display signal for each pixel based on the length value and the color data by a data developer 11. This signal is outputted to an image display device 14 through a video signal generating means 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image output method and an image output apparatus suitable for implementing the method, and more particularly to writing image data in a frame memory in a compressed state on the frame memory. The present invention relates to a technique for reducing the amount of use of a frame memory by expanding compressed data and displaying it on a display unit such as a display.

[0002]

2. Description of the Related Art Image output devices used for video game machines, personal computers, etc. are disclosed in, for example, JP-A-4-291424, JP-A-4-45488, JP-A-5-57062, and JP-A-5-57062. 5-324
As described in Japanese Patent No. 784, various types have been conventionally proposed.

These prior arts basically have a structure as shown in FIG. That is, in FIG. 5, 91 is a CPU that controls the entire apparatus, 92 is a ROM that stores a game program and image data, and 9
Reference numeral 3 is a command input means such as a control pad connected to the CPU 91 through an I / O port 94, and 95.
C for connecting the CPU 91 to the image output device side
It is a PU interface. The image output device is a CPU
Memory swap switch 96 controlled by 91,
Frame memory 9 for accumulating image data frame by frame
7 and the image data on the frame memory 97
A video display processor (VDP) 98 that reads out in synchronization with a vertical synchronizing signal and outputs as an RGB signal is provided, and its output side is connected to a display 99 such as a CRT.

In the conventional image output device having such a configuration, the CPU 91 executes the game program stored in the ROM 92 and, at the same time as the program is executed, a still image or a moving image to be displayed on the display screen of the display 99. Of the image data is written in the frame memory 97 via the CPU interface 95 and the memory swap switch 96. This frame memory 97
The image data written in the
After being read in synchronization with the vertical synchronizing signal, it is converted into an analog signal by the D / A converter of the VDP 96, input as an RGB signal to the display 99 and displayed on the screen.

In the conventional image output device of this type, the image data for displaying the image on the display 99 is written in the frame memory 97 for each screen by the bitmap method. For example, in FIG.
As shown in (A), it is assumed that the number of pixels on the display screen of the display 99 is 25, and that this display screen is composed of color A and color B. In that case, in the conventional technique, as shown in FIG.
Also in the above, the position and the color of each pixel are recorded in a state of corresponding one-to-one to each pixel of the display screen of the display 99.

[0006]

However, the writing of image data on the frame memory 97 corresponding to all the pixels of the display 99 has an inevitable drawback of increasing the frame memory capacity. Particularly in recent computers such as video game machines, the resolution of the display is improved and the number of pixels per screen is increased, so that the required frame memory capacity is also increased.

Further, in the conventional technique for writing the image data on the side of the ROM 92 in the frame memory 97 as described above, even when the image on the display screen is enlarged / reduced, rotated, transformed or moved, it is stored in the ROM 92. The image data representing the transformed image, the image data corresponding to the transformed image obtained by calculation based on the data stored in the ROM 92, and the frame memory 9 already written.
It is necessary to rewrite the above data. However, such rewriting of data imposes a burden on the CPU 91 and hinders the improvement of the image display speed.

Further, since the amount of data stored in the ROM 92 also increases with the lengthening of the program itself and the increase in the number of display colors and the resolution of images, this stored data is compressed and stored in the ROM 92. Various techniques are known. As one of the means for compressing such data,
There is a run length method. In the run-length method, when pixels having the same color are continuously displayed on the screen of the display 99, the number of pixels continuous with the color data (length of continuous same color data) is grasped. ,
The amount of data is compressed as compared with the case where color data is stored for every pixel.

However, in the conventional image output device, the compressed data stored in the ROM 92 is expanded into a one-screen bitmap image data by using the data expansion device by a method such as the run length method. The expanded image data was written in the frame memory 97. Therefore, even if the amount of data stored in the ROM 92 is small, the frame memory 97 needs to have the same capacity as when processing uncompressed image data, and the memory capacity cannot be reduced.

In particular, when the image is deformed or rotated, the calculation becomes complicated if the data remains compressed and the CPU is burdened. Therefore, conventionally, the compressed data is once expanded into a bitmap. I was writing to the frame memory. However, since the image rotation and transformation do not cover all of the image data and are often limited to a part of the image, all of the compressed data was expanded to bitmap. , The frame memory capacity was inevitably large.

The present invention has been proposed to solve the above-mentioned drawbacks of the prior art. The first object of the present invention is to produce a high-quality image with high resolution while using a frame memory with a small capacity. An object is to provide an image output method capable of outputting.

A second object of the present invention is to simply change the length value in the image data, and the image to be displayed can be easily changed without rewriting the image data in the frame memory. An object is to provide an image output method.

A third object of the present invention is to target only the image which requires the processing when the image display of the bit map system is necessary for performing the processing such as the deformation and rotation of the image. An object of the present invention is to provide an image output method capable of displaying data for each pixel similarly to the bitmap method.

A fourth object of the present invention is to provide an image output device capable of realizing the image output method according to claim 1 with a simple structure.

A fifth object of the present invention is to provide a data expanding means suitable for expanding the image data read from the frame memory into an image display signal based on the length value and the color data.

A sixth object of the present invention is to provide an image output device capable of transforming an image displayed by image data read from a frame memory by a simple means.

[0017]

In order to achieve the above object, an image output method according to a first aspect of the present invention is a length indicating the number of consecutive pixels of the same color data in the scanning direction of an image display device. The image data is configured by the value and the color data, the image data is written in the frame memory, the image data in the frame memory is read in time with the timing of the horizontal / vertical synchronization signal, and the image data is configured. An image is displayed on the image display device based on the length value and the color data.

According to a second aspect of the image output method, the image data having the length value and the color data written in the frame memory is read, and the length value in the image data is changed to display it on the image display device. The feature is that the image is deformed.

According to the image output method of claim 3, the length value is set to 1 when a plurality of pixels having the same color are continuously displayed for a part or all of the image data for one screen. It is characterized in that the image data is continuously written into the frame memory by the number of pixels of the same color.

An image output device according to a fourth aspect of the present invention is a raster scanning type image display device controlled by a horizontal / vertical synchronizing signal, and a pixel number in which pixels of the same color data are continuous along the scanning direction of the image display device. The image data is configured by the length value and the color data indicating, and the frame memory for writing the image data, the horizontal / vertical synchronization signal generating unit for controlling the image display device, and the timing of the horizontal / vertical synchronization signal are adjusted. Based on the length value and the color data forming the image data read from the frame memory, the color controller outputs color data for the number of pixels of the length value. Data expansion means for outputting the image display signal obtained by the data expansion means to the image display device. Characterized in that it includes a Oh signal generating means.

According to another aspect of the image output device of the present invention, the data expanding means outputs a length counter for counting the length value of the image data output from the frame memory, and color data of the image data during counter operation of the length counter. And a data latch circuit that operates.

An image output apparatus according to a sixth aspect of the present invention is characterized in that the data expansion means includes means for changing the length value in the image data read from the frame memory.

[0023]

According to the first aspect of the present invention having the above-mentioned structure, the image data written in the frame memory is compressed into the length value and the color data without expanding the image data into the bit map. Written to frame memory. Therefore, when pixels displayed by the same color data are continuously displayed, the capacity of the frame memory for writing the image data is reduced as the number of continuous pixels increases.

According to the second aspect of the invention, when the length value of the image data read from the frame memory is changed, the number of pixels of the same color displayed on the screen changes. Therefore, the image displayed on the image display device can be transformed without changing the content of the image data written in the frame memory.

According to the third aspect of the invention, even when pixels having the same color data are consecutive, the length value is set to 1
By doing so, the data can be processed for each individual pixel as in the bitmap method.

According to the fourth aspect of the invention, the CPU writes the image data in the ROM or the image data obtained as a result of calculating the data in the ROM to the frame memory by the program stored in the ROM. In this case, the image data is composed of the length value and the color data.
Therefore, for example, in a display screen with 25 pixels composed of color A and color B as shown in FIG.
As shown in FIG. 6C, only a length value, which is the number of pixels in which the same color is continuous, and a signal indicating the color of the pixel are written in the frame memory. As a result, the memory capacity required for the number of pixels of 25 in the case of the bitmap arrangement of FIG. 6B is reduced to 18 in the case of the present invention.

The image data written in the frame memory as described above is read out from the frame memory at the timing of the horizontal / vertical synchronizing signals by the action of the memory controller. The image data is composed of the length value and the color data, and the image cannot be displayed on an image display device such as a CRT as it is. Therefore, in the present invention, the image data is converted into an image display signal for each pixel based on the length value and the color data by the data expansion means, and then the image display signal is converted into a video signal such as a video encoder. It is output to the image display device via the signal generating means.

According to the fifth aspect of the present invention, when the image data read from the frame memory is sent to the data expanding means, the data expanding means stores the length value of the image data in the length counter and the color data in the data latch circuit. take in. From the data latch circuit, the color data for each pixel is output to the video signal generating means at the timing of the horizontal / vertical synchronizing signal. The length counter subtracts and counts the length value each time color data is output from the data latch circuit for each pixel. As a result, color data is output from the data latch circuit by the number of pixels corresponding to the length value.

According to the invention of claim 6, the length value changing means provided in the data expanding means changes the length value in the image data read from the frame memory. Then, since the number of pixels having the same color data output from the data expansion means is changed, different images are displayed on the image display device without changing the image data written in the frame memory. Can be displayed.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(1) Configuration of the Embodiment In FIG. 1, 1 is a CPU, 2 is a ROM for storing data such as programs and image data, and 3 is an I / O port 4.
Command input means connected to the CPU 1 via
Reference numeral 20 is an interface for connecting the image output means of the present invention and the CPU side.

Reference numeral 5 is a memory swap switch, and this memory swap switch is for switching a plurality of frame memories 6 and 6 provided in this embodiment. 7 is a VDP, and this VDP 7 is a frame memory 6
An image to be read from the memory controller 8 for controlling the reading of the image data from the camera, an image display device such as a CRT, and a horizontal / vertical synchronizing signal generator 9 for outputting the horizontal / vertical synchronizing signal to the memory controller 8 and the frame memories 6 and 6. Address pointer 1 that points to the address of the data
0, a development unit 11 for image data read from the frame memories 6 and 6, a D / A converter 12 and a video signal generating means 13. This video signal generating means 13
Are connected to the image display device 14 provided outside the VDP 7.

The data expansion unit 11 takes in the length counter 15 for taking in the length value in the image data, the length comparator 16 for detecting the value of the length counter 15, and the color data in the image data for horizontal and horizontal reading.
The data latch circuit 17 is provided for outputting in synchronization with the timing of the vertical synchronizing signal.

A color palette 18 is connected to the output side of the data expanding section 11 in the VDP 7, and a data expanding section 1 is provided between the data expanding section 11 and the color palette 18.
The image data expanded by 1 is transferred to the data expansion unit 11
A switch 19 is provided for selecting whether to directly output from the D / A converter 12 to the D / A converter 12 or to output to the D / A converter 12 via the color palette 18.

(2) Operation of Embodiment The operation of this embodiment having the above-mentioned configuration will be described with reference to the block diagram of the image data written in the address of the frame memory of FIG. 2 and the flowchart of FIG.

First, the CPU 1 is a CD-ROM or ROM.
The program is read from the ROM 2 such as a cartridge and executed, and the image data included in the program is read by the CPU.
Writing to the frame memory 6 via the interface 5. The image data in this case is composed of the length value and the color data, and may be stored in the ROM 2 as it is, or the display image may use polygons.
In the case of a D image, it may be data calculated based on the data in the ROM 2. Further, the data stored in the ROM 2 may be processed based on the command given by the command input means 3 connected to the CPU 1.

The image data written in the frame memory 6 is, for example, the data of the n-th line of the image display device as shown in FIG. The image data is written in the form shown in. That is, the color data A indicating the first pixel n0 of the line n and the length value 0 indicating the number of consecutive pixels 1 of the color data are written in the address m of the frame memory 6, and the next address m + 1 is written in As the second and third pixels n1 and n2 of the line n, the length value 1 indicating the number of pixels 2 continuous with the color data B is written. Similarly, at each address of the frame memory 6, the length value and the color data of the pixel of each line are written.

When the image data is written in the frame memories 6 and 6 by the CPU 1, the memory swap switch 5 controlled by the CPU 1 is switched to determine which of the two frame memories 6 and 6 is to be written. It The frame memory that is not on the data writing side by the CPU 1 is used for reading data by the VDP 7. By using the dual mode type frame memory using the memory swap switch 5 as described above, it is possible to read and write image data at the same time.

After the image data is written in the frame memory 6, the CPU 1 controls the memory swap switch 5 to set the frame memory 6 in which the data is written to VDP7.
Connect to. Horizontal / vertical sync signal generator 9 of VDP 7
Outputs the horizontal / vertical synchronizing signals for generating the image display signal to the video signal generating means 13, and at the same time, to the memory controller 8, the horizontal and vertical positions on the image display device 14 of the pixel to be displayed. Is informed. The memory controller 8 reads the image data written in the corresponding address of the frame memory 6 based on the horizontal / vertical synchronization signal.

That is, as shown in the flow chart of FIG. 3, first, the memory controller 8 sets the base address of the frame memory 6 in the address pointer 10 and indicates that the display is performed from the first pixel of the line. A counter indicating horizontal resolution is set to N = 0 (step 1). Then address pointer 1
The image data is read from the address of the frame memory 6 set to 0. Among the image data, the length value data is fetched by the length counter 15 and the color data is fetched by the data latch circuit 17 (step 2). The color data for one pixel in the data latch circuit 17 is output to the D / A converter 12 according to the display signal for each pixel sent from the horizontal / vertical synchronizing signal generator 9 (step 3).

In this case, the switch 19 is switched according to the structure of the color data forming the image signal. That is, when the color data can be directly used by the video signal generating means 13, the output from the data latch circuit 17 is directly output to the D / A converter 12 as color data. When the color data output from the data latch circuit 17 indicates the address of the color palette 18, the color data corresponding to the input address is output from the color palette 18 to the D / A converter 12. It

In this way, when the color data for one pixel is output from the data latch circuit 17, the counter indicating the horizontal resolution is incremented by one (N = N + in step 3).
1), N reaches the value of horizontal resolution, and color data is output until all pixels for one line are displayed (step 4). That is, every time one pixel of data is output from the data latch circuit 17, the content of the length counter 15 is judged by the length comparator 16 to be "0" (step 5). If the determination result is not "0", it is necessary to continuously display pixels of the same color, so the length value taken into the length counter 15 is decremented (step 6), and the process returns to step 3. Then, the output of the color data from the data latch circuit 17 is repeated.

On the other hand, when the pixels having the same color data are output by the number corresponding to the length value, the output of the length counter 15 becomes "0", so that the address pointer 10
Is incremented (step 7), the next image data is read from the frame memory 6, and the length value of the length counter 15 and the color data of the data latch circuit 17 are updated (step 2).

Thereafter, in the same manner, the data latch circuit 17
From the above, color data of the same color for the number of pixels corresponding to the length value is output to the D / A converter 12. In the D / A converter 12, the color data is converted into an analog RGB signal, and the analog RGB signal and the horizontal / vertical synchronizing signals are further combined in the video signal generator 13 to generate an image display signal. It is output to 14.

(3) Effect of Embodiment As described above, according to this embodiment, as is clear from the data structure diagram on the frame memory in FIG. 2, when the pixels of the same color are consecutive, the image data is The capacity of the frame memory to be written can be reduced. In particular, many images used for games and business programs have continuous pixels of the same color, such as the background portion, so the memory capacity is much smaller than writing by the normal bitmap method. .

On the other hand, even when pixels of the same color are continuous,
By setting the length value to 1, it is possible to process each pixel as one image data as in the case of the bitmap. Therefore, in one screen written in the frame memory, only the specific portion that needs to be deformed such as rotation is treated as a bitmap with the length value set to 1, and the other portions correspond to the number of consecutive pixels of the same color. By setting the length value as described above, it is possible to simultaneously achieve the effects of both simplification of the arithmetic processing required for deformation and the like and reduction of the frame memory capacity.

(4) Other Embodiments The present invention is not limited to the above-described embodiments, and as shown in FIG. 4, it is provided at the front stage of the length counter 15 for fetching the length value data from the frame memory 6. ,
A length value changing means 21 controlled by the CPU 1 may be provided. By changing the length value of the image data read from the frame memory 6 by the length value changing means 21, the number of pixels of the same color output from the data latch circuit 17 can be changed freely, so that the frame memory 6 can be rewritten. The image displayed on the image display device 14 can be deformed without performing.

[0048]

As described above, according to the present invention, since the image data to be written in the frame memory is composed of the length value and the color data, the capacity of the frame memory can be reduced and the image can be deformed or rotated. CPU processing
It is possible to provide an image output method and an image output method that can be quickly performed without burdening the user.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image output device according to the present invention.

FIG. 2 is a diagram showing a structure of a display image and image data on a frame memory in the embodiment of FIG.

FIG. 3 is a flowchart illustrating the operation of a data expansion unit 11 in the embodiment of FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a block diagram showing an example of a conventional image output device.

FIG. 6 is a diagram showing a relationship between a display image and a frame memory in which the data is written.

[Explanation of symbols]

 1 ... CPU 2 ... ROM 3 ... Command input means 4 ... I / O port 5 ... Memory swap switch 6 ... Frame memory 7 ... Video display processor (VDP) 8 ... Memory controller 9 ... Horizontal / vertical sync signal generator 10 ... Address Pointer 11 ... Data expansion unit 12 ... D / A converter 13 ... Video signal generating means 14 ... Image display means (CRT) 15 ... Length counter 16 ... Length comparator 17 ... Data latch circuit 18 ... Color palette 19 ... Switch 20 ... CPU interface 21 ... Length value changing means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G09G 5/36 530 W 9471-5G

Claims (6)

[Claims] 1. A raster scanning type image display device controlled by horizontal / vertical synchronizing signals, wherein image data for displaying on a screen-by-screen basis in the image display device is written in a frame memory, and the image data is written from the frame memory. In the image output method for displaying an image on the image display device based on the read image data, the length value and the color data indicating the number of consecutive pixels of the same color data along the scanning direction of the image display device. The image data is formed by and the image data is written in the frame memory, the image data in the frame memory is read in synchronization with the timing of the horizontal / vertical synchronization signals, and the length value and the color forming the image data are read. An image output method comprising displaying an image on the image display device based on data. 2. An image displayed on an image display device is deformed by reading image data having a length value and color data written in a frame memory and changing the length value in the image data. The image output method according to claim 1, which is characterized in that. 3. When a plurality of pixels having the same color are continuously displayed for a part or all of the image data for one screen, the image data having a length value of 1 is displayed in the same color. The image output method according to claim 1, wherein the number of pixels is continuously written in the frame memory. 4. A raster scanning type image display device controlled by horizontal / vertical synchronizing signals, and a length value and color data indicating the number of consecutive pixels of the same color data along the scanning direction of the image display device. The image data is configured by and a frame memory for writing the image data, a horizontal / vertical synchronization signal generation unit for controlling the image display device, and an image on the frame memory according to the timing of the horizontal / vertical synchronization signal. A memory controller for controlling the reading of data; a data expanding means for outputting color data corresponding to the number of pixels of the length value based on the length value and the color data constituting the image data read from the frame memory; Video signal generating means for outputting the image display signal obtained by the data expanding means to the image display device. An image output apparatus characterized by there. 5. The data expanding means comprises a length counter for counting a length value of image data output from a frame memory, and a data latch circuit for outputting color data of image data during counter operation of the length counter. The image output device according to claim 4, which is provided. 6. The image output apparatus according to claim 4 or 5, wherein said data expanding means comprises means for changing a length value in the image data read from the frame memory.