JP3575889B2 - Color addition circuit in image processing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color addition circuit in an image processing apparatus such as a video game machine.
[0002]
[Prior art]
In image processing such as a game machine, one color palette number and color code are generally designated for one pixel which is a data point, and the designated color is output. If it is expressed in other colors, it is necessary to change the palette number and color code.
If another character overlaps one pixel expressing one color by specifying the palette number and color code, if the character has a translucent color, the pixel will be the color obtained by adding that color. Must be.
In this way, color addition is to create two other colors by overlapping two colors, and it is desirable that this can be realized on the screen.
[0003]
Various methods of color addition have been conventionally considered.
FIG. 4 is a circuit block diagram showing an example of a color addition circuit which has been conventionally considered.
When color addition is performed for the background image and the object, the pixel information at the same position is input to the priority circuits 21 and 22, respectively, and the display priority is determined. The two palette circuits 23 and 24 output RGB signals based on the palette numbers and color codes from the priority circuits 21 and 22, respectively. These RGB signals are color-added by the adding unit 25, and a mixed color is output.
[0004]
[Problems to be solved by the invention]
The color adder circuit that has been considered in the past performs color addition after passing through the priority circuit and palette circuit of the object and background image in this way, so there are two priority circuits and palette circuits for color addition. It was necessary to prepare, the circuit configuration became complicated, and the price reduction was requested.
The object of the present invention is to meet the above-mentioned demand. In image processing that can simplify the circuit and realize low cost by adding colors using one priority circuit (object / background image switching means) and a palette circuit. The object is to provide a color addition circuit.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the color addition circuit in the image processing according to the present invention is the same pixel position on the display screen of the object information and the background image information in the color addition circuit in the image processing for superimposing the colors of the pixels of the background image and the object. Object / background image switching means for alternately switching and outputting pixel information, a palette circuit for outputting RGB signals based on pixel information output from the object / background image switching means, and object information output from the palette circuit and holding means for holding one of the RGB signals of the same pixel position of the background picture information, and one of the RGB signals of the same pixel position of the object information and the background picture information held in the holding means, then output from the palette circuit the other RGB signals of the same pixel position of the object information and the background image information is It is composed of a summing circuit for adding and.
[0006]
According to the above configuration, for example, when a pattern written on ground glass is placed in front of the background image, the background image should look like a color that is superimposed on the ground glass pattern, but with a simple configuration The above color addition can be realized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is an overall block diagram of a game machine using a color addition circuit in image processing according to the present invention.
When a coin is inserted into the coin related device 15, it is transmitted to the CPU 11 via the input / output control device 13, and the game is started. The backup memory 12 stores setting values for the number of coins, the number of plays, and the difficulty level. The CPU 11 reads a program for controlling the entire game from the program ROM 16 and controls the video control circuit 9 according to the read program to display an initial screen on the CRT 10.
The work RAM 17 is an area used when the CPU 11 performs calculations.
[0008]
The communication RAM 18 stores a command of the CPU 11 relating to sound, and is used when the CPU 11 confirms the sound status.
Sound is generated by the sound system circuit 19, and the sound is output from the speaker 20.
The character ROM 8 connected to the video control circuit 9 stores characters (16 × 16 dots) constituting the background image, and the character at the address read from the screen RAM 7 is read out. The screen RAM 7 has N background images, and by superimposing these, a screen with a sense of depth can be produced. The buffer circuit 6 is a bitmap type memory and stores an OBJ character for displaying the frame.
[0009]
The character read based on the screen RAM 7 and the object read from the buffer circuit 6 are processed by an adder circuit according to the present invention described later and displayed on the CRT 10.
The adding circuit according to the present invention comprises an object / background image switching circuit 1, a palette circuit 2, a flip-flop circuit 3, an adder 4 and a D / A conversion character 5.
When the pixel positions of the object read from the buffer circuit 6 and the character of the background image are the same, they are input to the object / background image switching circuit 1 at the same timing. The object / background image switching circuit 1, the palette circuit 2, the flip-flop circuit 3, and the adder 4 are operated at a speed (clock frequency f ₁ = 2f) that is twice the speed of the other circuits (clock frequency f). It has become.
[0010]
FIG. 2 is a circuit block diagram showing an embodiment of a color addition circuit in image processing according to the present invention.
In the object / background image switching circuit 1, half the cycle time of the other circuits is switched to the object side, and the remaining half cycle is switched to the background image side. First, object information is input to the palette circuit 2 in dot units (having a palette number and color code information for each dot).
The palette circuit 2 stores RGB signals designated by palette numbers and color codes as shown in FIG.
Therefore, the RGB signal based on the object information is read from the palette circuit 2 in dot units and held in the flip-flop circuits 3a, 3b and 3c.
[0011]
Background image information is input to the palette circuit 2 in dot units in the next half cycle, and the RGB signals are read out in the same manner.
The adders 4a, 4b and 4c are inputted with RGB signals based on the background image information from the palette circuit 2 and RGB signals based on the object information held in the flip-flop circuits 3a, 3b and 3c, and are respectively added. .
The added output is converted into an analog signal by the D / A converter 5 and sent to the CRT.
Similarly, for the next overlapping pixel, the RGB signal of the object information is read out with a half period of one cycle time of the other circuit, and the RGB signal of the background image is read out with the other half of the period, and the colors are added. This operation is repeated for each overlapping pixel.
If the object information and the background image information do not overlap, they are input to the object / background image switching circuit 1 at different timings, so that they are added by the palette circuit 2, the flip-flop circuit 3, and the adder 4. There is no.
[0012]
【The invention's effect】
As described above, the present invention alternately outputs pixel information at the same pixel position on the display screen of the object information and the background image information in the color addition circuit in the image processing for superimposing the colors of the background image and the object pixel. Object / background image switching means, a palette circuit that outputs RGB signals based on pixel information output from the object / background image switching means, and the same pixel position of the object information and background image information output from the palette circuit Holding means for holding one of the RGB signals, one RGB signal at the same pixel position of the object information and background image information held in the holding means, and then the object information and background image information output from the palette circuit It is composed of a summing circuit for adding the other RGB signals for the same pixel position of There.
Therefore, since the priority circuit and the palette circuit are one system, the cost can be reduced as compared with the conventional color addition circuit.
For example, it can be suitably expressed for display of a background image through glass.
This addition function and resolution enhancement can be switched and used as modes.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall block of a game machine using a color addition circuit in image processing according to the present invention.
FIG. 2 is a circuit block diagram showing an embodiment of a color addition circuit in image processing according to the present invention.
FIG. 3 is a circuit diagram showing details of a pallet circuit.
FIG. 4 is a circuit block diagram illustrating an example of a color addition circuit in conventional image processing.
[Explanation of symbols]
1. Object / background image switching circuit (priority circuit)
2 ... pallet circuit 3, 3a, 3b, 3c ... flip-flop circuit 4, 4a, 4b, 4c ... adder 5 ... D / A converter 6 ... buffer circuit 7 ... background image RAM
8 ... Character ROM
9 ... Video control circuit 10 ... CRT

Claims (1)

In the color addition circuit in the image processing that overlaps the color of the pixel of the background image and the object,
Object / background image switching means for alternately switching and outputting pixel information of the same pixel position on the display screen of object information and background image information,
A palette circuit that outputs RGB signals based on pixel information output from the object / background image switching means;
Holding means for holding one RGB signal at the same pixel position of the object information and the background image information output from the palette circuit;
One RGB signal at the same pixel position in the object information and background image information held in the holding means is added to the other RGB signal at the same pixel position in the object information and background image information output from the palette circuit. And an adder circuit to
A color addition circuit in image processing, comprising:

Images