JPS61129694A - Superimposed display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device that displays two or more types of video signals in a superimposed manner on the screen of one display device.

Recently, CAI (Computer Aided In5
Auditory-visual education using terminals (transaction) is being actively carried out.

The above-mentioned CAT terminal converts educational explanatory text, question text, answer text, etc. generated by a computer into a video signal,
It is displayed superimposed on a video image that serves as a teaching material.

In addition, for example, on terminals for sales promotion used in stores etc., explanatory text for sales promotion generated by a computer can be converted into a video signal and displayed superimposed on the video image of the product targeted for sales promotion. It will be done.

In such a case, it is required to effectively display explanatory text generated by the computer on the background video image for teaching materials or sales promotion.

[Conventional technology]

Figure 4 shows a block diagram of an example of a general superimposed display device.
1 is a processor (CPU), 2 is a random access memory (hereinafter referred to as RAM), 3 is a file memory (FM), 4 is a display control circuit, 5 is a display (CRT), and 6 is a video signal source. (VSS)
For example, there are VTRs, video cameras, etc. 7 is a human powered device (eg, keyboard, touch screen, etc.).

In such a superimposed display device, when the power is turned on, the operating system (O3) and various image generation programs are loaded from the file memory (FM) 3 to the RAM 2 through initial program loading (IPL).
When the initial program loading (IPL) is completed, the processor (CPtl) 1
By executing the above various programs stored in the AM 2 under the management of the operating system (OS), the display control circuit 4 is controlled and the video from the background video signal source (VSS) 6 is controlled. For the signal
The characters, figures, etc. generated by the above image generation program are converted into video signals and superimposed on the display (CRT).
It operates to display on the screen of 5.

The input device 7 is the CAI terminal, the sales promotion terminal,
Used when inputting a response signal.

In this case, in the conventional method, (1) For example, a character generator (CG) 41 generates a dot signal corresponding to the character code of the explanatory text that is output from a computer, and the dot signal is transmitted to the video Synchronous signal (SYN) from signal source (VSS) 6
After being converted into a video signal synchronized with , it functions as a control signal C for a video control circuit (VCTL) 42
The video signal from the video signal source (VSS) 6 is suppressed corresponding to a pixel (dot) which is the minimum unit of the character pattern data, and the suppressed video signal and the character pattern signal converted into a video signal are combined. (dot signal) are added in analog form by an adder circuit (800) 43 and displayed in a superimposed manner on a display (CRT) 5.

■Specific frame in which a character pattern exists (for example, nXm dot) output from the character generator (CG) 41 mentioned above.
function a video signal corresponding to the control signal C as a control signal C;
The video signal from the video signal source (VSS) 6 is suppressed by the video control circuit (VCTL) 42, and the suppressed video signal and the character pattern (dot signal) converted into the video signal are added to the adder circuit (ADD). Analog addition is performed at 43 and displayed on a display (CRT) 5 to improve the superimposition of character patterns.

method is known.

[Problem that the invention seeks to solve]

In such a conventional method, in the method of suppressing the background video signal only for the pixel (2), if the image from the background video signal source is complex, the superimposed characters, figures, etc. However, there was a problem that it was extremely difficult to read.

■Character generator (CG) 41, for example nxm de, 7
In this method, the reading performance of the character pattern can be improved, but the reading performance of the character pattern can be improved. , there was a problem that it could not be applied to figures that cannot be coded.

In view of the above-mentioned conventional drawbacks, the present invention has been developed in order to obtain a variety of color tones with a small amount of image memory in the color graph ink display of the rask display type that has been widely used in the past.
Focusing on the fact that a conversion table (look-up table (LUT)) is used, for example, using the conversion table (LIIT), computer-generated character 9 image data etc. can be applied to a background video signal. The purpose of the present invention is to provide a method for overlapping images.

[Means for solving problems]

This purpose is to provide a color tone conversion table (LUT) circuit in at least one video signal generation system and to provide a color tone conversion table (LUT) circuit in at least one video signal generation system.
r) Controlling the intensity of video signals other than the video signal system provided with the color tone conversion table (LIT) circuit among the plurality of video signals by one or more outputs of the circuit to produce various superimposed displays; This is achieved by the superimposed display device of the present invention.

[Effect]

That is, according to the present invention, image data such as characters generated by a computer is temporarily stored in an image memory, and when the image data is read out, it is synchronized with a video signal from another video signal source, and the video data is After converting into a signal, accessing a conversion table (lookup table (LUT)) with the video signal and suppressing the other video signal with a suppression ratio specified by the contents of the lookup table (LUT). Since the above-mentioned other video signals are suppressed by the control signal C, various types of superimposed display such as simple superimposition, background half-brightness superimposition, etc. can be performed.
In the above image memory, it is possible to arbitrarily specify an area where other video signals can be suppressed, so multiple video signals can be superimposed in any form, the superimposed screen can be easily recognized visually, and a variety of superimposed screens can be obtained. It has the effect of

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 schematically shows an embodiment of the present invention, and shows an example in which the present invention is applied to the display control circuit 4 of the conventional superimposed display device described in FIG.

Figure 2 is a diagram showing an example of the configuration of a lookup table (hereinafter referred to as LOT), which is the main focus of the present invention, and Figure 3 shows the process of generating a screen displayed by implementing the present invention. It is a diagram.

In FIG. 1, the same reference numerals as in FIG. 4 indicate the same objects. LUT 4
A 5.5' digital to analog converter (D/A) 46 is a necessary functional block to implement the present invention.

Hereinafter, while referring to the general superimposed display device shown in Fig. 4,
The process of generating and displaying a superimposed image by implementing the present invention will be explained with reference to FIGS. 1 to 3.

First, nine character graphics (in this example, the English letters A, B, C, and D) generated by the processor (CPtl) 1 are stored in an image memory (GM) consisting of, for example, four screens.
)44.

In this embodiment, the image memory (GM) 44 corresponds to each pixel constituting the nine character shapes to be displayed.
It uses a bitmap method that corresponds to a 1-bit memory element, and has four screen memories, but a more precise superimposed display device will have even more screen memories, allowing for a variety of expressions. be able to.

In this example, the conversion table (LUT) 45 inputs a signal obtained by converting the output data of the four screen memories into a video signal synchronized with other video signals,
It outputs four control signals: green (G), blue (B) brightness control signals, and a superimposition control signal C for the video control circuit (VCTL) 42.

Each control signal may have any number of bits; for example, the brightness control signals of R; G and B may each have 4 bits, and the superimposition control signal C may have 2 bits.

At this time, one pixel can only have 2'(n・4) 16 different brightness states, but the displayed color tones are 2
It is possible to select from a range of 4096 colors (°(n=4+4+4)), and 2' (n=2)=4 superimposition modes can be selected.

Video control circuit (VCTL) 42 is a video signal source (V
The amplitude of the video signal from SS) 6 is controlled according to the superimposition control signal C, and as an example, corresponding to the 2-bit signal, the amplitude of the video signal is 1, L/2.1/4°0.
It may be controlled to attenuate as shown in FIG.

Digital to analog converter (D/A) 46 is LII
The adder circuit (ADD) 43 converts the digital output signal of the T 45 into an analog signal, and the adder circuit (ADD) 43 converts the amplitude-suppressed video signal from the video control circuit (VCTL) 42 and the digital-to-analog converter (D/^ ) 46 to generate a video signal and display it on the display (CRT) 5.

In the present invention, an arbitrary superimposition effect can be obtained by the information written into the image memory CGFI) 44 and the value set in advance in the LOT 45.

FIG. 2 shows an example of the configuration of the LIT 45.
(a) shows an example of simple superimposition, and (b) shows an example of background half-brightness superimposition.

That is, in (a), if the output of any of the screens 1, 2, 3.4 of the image memory (GM) 44 consisting of four sides is not "Oo", the superimposition control signal C is set to "0". As a result, for pixels that have some kind of signal on the screen memory, the video signal from 1 video signal source (VSS) 6 is controlled to be suppressed to "0", so simple superposition is performed. I understand that.

Next, in the example of (b), the screen memory 4 is used to control the superimposed background, and if there is display information in any of the screen memories 1, 2, or 3, the video corresponding to that pixel is displayed. The video signal from the signal source (VSS) 6 is suppressed to "0", and only in the area where the output of the screen memory 4 is "1" and there is no display signal on other screen memories, the video signal source (VSS) is suppressed to "0". ) The intensity of the video signal from 6 is controlled to be 172.

FIG. 3 shows an example of a superimposed screen subjected to such superimposition control, where ■ indicates the image data of screens L2 and 3 (
For example, the letters ^, B, C, D) are shown, ■ indicates the image data for the superimposed foreground control of the screen 4, ■ indicates the background image from the video signal source (VSS) 6, and ■ A superimposed display screen on a display (CRT) is shown.

With such screen information, the LO shown in FIG. 2(b)
When superimposition control is performed using the setting information of T45, "1" of ■
In the ゛ area, only for the area without the alphabetic character ■,
The background image of (3) is suppressed to 172, and the portion corresponding to each pixel of the English letters in the area is.

Since it is suppressed to 0', the English character can be clearly read, but the English character in the area that is not subject to suppression control (the "0' area of ■)" (in this example,
It can be seen that the English letters ``口'') are buried in the background image and are difficult to read.

In this way, in the present invention, the image memory (GM) 4
By changing the data set in LtlT 45 corresponding to the area that can be specified in 4, in any superimposition mode,
For example, since the background video signal from the video signal source (VSS) 6 can be suppressed, not only characters but also graphics can be displayed in a superimposed manner that is easy to see.

〔Effect of the invention〕

As described above in detail, the superimposed display device of the present invention temporarily stores image data such as characters generated by a computer in an image memory, and when reading out the image data, the superimposed display device stores computer-generated image data such as characters, etc. After synchronizing with the video signal and converting it into a video signal, a conversion table (look-up table (LUT)) is accessed with the video signal, and a suppression ratio specified by the contents of the look-up table (LUT) is used. ,
A control signal for suppressing the other video signal is generated, and the other video signal is suppressed by the control signal, so that various types of superimposition display such as simple superimposition, background half-brightness superimposition, etc. In addition, the image memory allows you to arbitrarily specify an area where other video signals can be suppressed, so multiple video signals can be superimposed in any shape, making it easy to visually recognize the superimposed screen, and allowing a variety of This has the effect of providing a superimposed screen.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing an embodiment of the present invention for a display control circuit in a superimposed display device. FIG. 2 is a diagram showing an example of the configuration of a lookup table (LtlT). FIG. 3 is a diagram schematically showing the process of generating a superimposed display screen by implementing the present invention. FIG. 4 is a block diagram showing a configuration example of a general superimposed display device. It is. In the drawing, 1 is the processor (CPU). 2 is random access memory (RAM). 3 is a file memory (Fl'l). 4 is a display control circuit, and 41 is a character generator (CG). 42 is a video control circuit (VCTL). 43 is an addition circuit (ADD), 44 is an image memory (
GM). 45 is a lookup table (LUT). 46 is a digital to analog converter (D/A). 5 is a display (CRT), 6 is a video signal source (VS
S). 7 is a human powered device. ■～■ are image data, ■ are superimposed display screens. are shown respectively. Brown 1 Prisoner cpu+ ¥-2 figure ((1) (shi) Brown 3 figure bidet 1r island statue

Claims (1)

[Claims] A device that superimposes and displays a plurality of video signals, the device including a color tone conversion table (LUT) in at least one video signal generation system.
) A circuit is provided, and one or more outputs of the color tone conversion table (LUT) circuit determine the intensity of a video signal other than the video signal system provided with the color tone conversion table (LUT) circuit, among the plurality of video signals. What is claimed is: 1. A superimposed display device characterized in that the superimposed display is controlled to obtain various superimposed displays.