JPS6171792A - Superimpose circuit - Google Patents

Abstract

PURPOSE:To attain a single color adjustment of a character/graphic signal from a computer by selecting either of a digital three primary color signal from a digital matrix circuit and a combination circuit for outputting said signal and an input from the combination circuit in accordance with a command and providing a selector circuit for superimposing and outputting both of them. CONSTITUTION:The action of a superimpose inputs simultaneously the highest order bit MSB to lowest order bit LSB of signals R, G and B outputted from a digital matrix circuit 14 and signals from the MSB to LSB of an I demodulation combination circuit 15 corresponding to each signal to a digital selector 16, and a mode switching signal 11 switches pictures of a television and computer in units of bit. Since an analog signal will not mix with a digital signal in the same circuit, a digital switching noise mixed on a signal line can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a superimpose circuit suitable for use in high-definition color displays and the like aimed at significantly improving image quality.

[Background of the invention]

The superimpose circuit referred to here is a TV tuner or video disc player (hereinafter abbreviated as VDP).
, an image based on a video signal generated from a video signal generation source such as a video tape recorder (hereinafter abbreviated as VTR), and an image generated from a text/graphic signal generated from a text/graphic signal generation source such as a computer on the same screen. This is a circuit for superimposing and displaying.

FIG. 2 is a block diagram showing a conventional superimpose circuit.

As shown in FIG. 2, a television tuner and Vl)P.

A composite video signal 1 output from one of the VTRs (not shown) is input to a video signal processing circuit 4 which has image quality adjustment functions such as color tone and color density, and is processed to produce a luminance signal Y and color difference. It is converted into signals R-Y and B-Y.

Furthermore, these signals are converted into analog R, G, and B signals by an analog matrix circuit 5 and input to an analog data selector circuit 6. Further, in synchronization with this signal, character/graphic three primary color signals (digital R9G, B signals) from a computer (not shown) are also input to the analog data selector circuit 6.

The analog data selector circuit 6 is controlled by the mode switching signal 3, and the display mode can be set to [TV], [computer], [
Selected from [Super Invoice]. When the display mode is [TV], the analog data selector circuit 6
outputs analog R1G, B signals (output signals from the analog matrix circuit 5), and outputs digital R, G, B signals (output signals from the computer) when the display mode is [computer]. Further, when the top of the display is [Superimpose], the output is switched bit by bit to perform superimposition.

Then, R from this analog data selector circuit 6,
The G and B output signals are input to the display 8 via the video amplification circuit Z.

In the conventional superimpose circuit shown in Fig. 2, when switching between an analog signal (analog R1G, B signal) and a digital signal (digital R1G, B signal) as described above, the analog signal and digital signal are connected to the same circuit. Because of this, digital switching noise gets mixed into the signal line, crosstalk occurs inside the analog data selector IC, and image quality deteriorates.
There was a drawback.

Furthermore, since the analog data selector circuit 6 uses an expensive analog data selector ICf, it is economically disadvantageous.
Since more than 0 points are required, the circuit scale becomes large and takes up too much space.

It also lacked reliability.

Furthermore, since it is impossible to adjust the brightness level of the character Φ figure three primary color signals (digital R, G, E signals) output from the computer, images produced by these signals inevitably have poor color expression. there were.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and therefore, an object of the present invention is to improve image quality, be economical and reliable, and have a small circuit scale, and to provide a computer It is an object of the present invention to provide a superimpose circuit which enables independent color adjustment of character and graphic signals from a .

[Summary of the invention]

The present invention aims to achieve all of the above objectives.

A video signal processing circuit that processes a video signal from a video signal generation source and outputs a luminance signal and a color difference signal, and an A/D that converts the luminance signal and color difference signal from analog quantities to digital quantities.
A conversion circuit, a digital matrix circuit that converts the digital luminance signal and color difference signal from the conversion circuit into all five primary color signals and outputs them, and a digital matrix circuit that receives the digital three primary color signals and luminance specification data from the character/figure signal source and converts the luminance signal. A combinational circuit that outputs digital three primary color signals containing information, and inputs the digital three primary color signals from the digital matrix circuit and those from the combinational circuit, selects one of them according to a command, or selects one of them according to a command, or supervises both of them. It consists of a selector circuit that imposes and outputs, and the output from the selector circuit is output to all display devices.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 3.

FIG. 1 is a block diagram showing one embodiment of the present invention. 8
As shown in Figure 1'L1, TV cheese and FDP,
A composite video signal 9 output from one of the VTRs (not shown) is input to a video signal processing circuit 12 having image quality adjustment functions such as color tone and color saturation, where it is processed and has a brightness signal Y and a , color difference signals R-Y, BY, and are converted by the A/D conversion circuit 13 into, for example, 8-bit digital luminance signal Y and color difference signals R-Y, BY, respectively, and output. Further, the signals are converted into, for example, 8-bit RoG, 13 signals in the digital matrix circuit 14 and input to the digital data selector circuit 16.

ti, the character salary figure signal 10 output from a computer (not shown) includes R, G, E signals (1 bit each) and I
A signal (17Ltanzity signal: A signal that controls all information about brightness; logic ``1'' represents a brightness tone, and logical addition represents a full brightness tone);
Each is input to the I demodulation combination circuit 15, and luminance demodulation (hereinafter referred to as I demodulation) is performed as an I signal total control signal (detailed operation will be explained later). For example, each 8-bit R , G, and B signals. These output signals are input to the digital data selector circuit 16 in synchronization with the digitized R, G, and B signals (for example, 8 bits each) from the composite video signal 9 described above.

The digital data selector circuit 16 is controlled by the mode switching signal 11 for switching the display mode, and when the display mode is [TV], the R2O, B signal (
That is, when the display mode is [computer], the R, G output from the I demodulation combination circuit 15 is
, all B signals (i.e., signals generated by all computers) are output. In addition, when the display mode is [suit-imposed], all output switching and superimposition are performed in units of biy).

For example, each 8-bit R, G, and B signal output from the digital data selector circuit 16 is
The conversion circuit 17 converts the signals into analog RoG and B@ signals, which are displayed on the display 18.

FIG. 3 is a block diagram showing the signal line connection state of the main part in FIG. 1.

Superimposition and the operation of the I demodulation combination circuit 15 will be explained with reference to FIG.

As shown in FIG. 3, superimposition refers to the transition from the most significant pit (hereinafter abbreviated as MSB) to the least significant bit (hereinafter abbreviated as LSB) of the RlG and B signals output from the digital matrix circuit 14. , I corresponding to each signal
The signals from MSB to LSB of the demodulation combination circuit 15 are simultaneously input to the all-digital data selector 16, and the mode switching signal 11 switches between the television picture and the computer picture dot by dot.

Next, the operation of the I demodulation combination circuit 15 will be explained.

For example, by adding a 1-pit I signal to the three primary color symbols R2O and H as the output of a 16-bit personal computer,
Conventional 8-period PC RlG, 8 colors of E33 original (=
23), it is possible to express 16 colors (=2') including full tones and no-f tones.

These R, G, E and I signals are input to the I demodulation combination circuit 15 as a character/solid signal 10 as shown in FIG.

Incidentally, the number of bits and nodes of the R, G, and B signals of the computer output from the I demodulation combination circuit 15 and input to the digital data selector circuit 16 are as follows.

Each of B and I has 1 bit, but the output stage thereof has the same number of bits as the R, G, and B output signal bits of the digital matrix circuit 16 (for example, 8 bits each). For example, if the R, G, and E signals output from the combinational circuit 15 are 8 bits each, depending on the state of the I signal, any full tone or half tone tone fR, G, B can be independently divided into 256 gradations. (26) It is possible to select and output.

That is, the output of the I demodulation combination circuit 15 is full tone from the most significant pit (hereinafter abbreviated as MSB) to the least significant pit (hereinafter abbreviated as LSE) (1111111
1), the halftone is (Qllllllll
) or (oollllll).

Furthermore, considering the visual characteristics of the eyes for the three primary colors R, G, and E, it is possible to set all independent levels for each color. In other words, it becomes possible to adjust the color of the character/graphic signal of the computer alone, and to perform offset adjustment and white balance adjustment using the I demodulation combination circuit 15.

With such an I demodulation method, by adding 1 strength signal line in addition to the I signal, it is possible to express 2+1 colors.

According to this embodiment, analog signals (video signals from a TV tuner, etc.) and digital signals (character/graphic signals from a computer) are not mixed in the same circuit, so they are not mixed in the signal line. Digital switching noise can be eliminated, crosstalk problems can also be improved, and image quality can be improved. Furthermore, in this example, the entire circuit is constructed using digital ICs, but digital ICs are inexpensive, easy to use, and do not require peripheral elements, so they are extremely reliable and economical. It's advantageous. Furthermore, the digital IC does not require all peripheral elements, and the package of the IC is compact, so by using the digital IC, the circuit scale can be kept small and space can be utilized effectively.

〔Effect of the invention〕

According to the present invention, digital switching noise can be eliminated and crosstalk can be improved, image quality can be improved, and the circuit can be configured with an inexpensive and easy-to-use digital IC, so reliability and economic efficiency can be improved. This has the effect of making it possible to achieve this goal. Furthermore, the I demodulation combination circuit enables color adjustment of the character/figure signals from the conbeater alone, and also enables offset adjustment and white balance adjustment.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing a conventional superimpose circuit, and Fig. 3 is a block diagram showing an embodiment of the present invention.
The figure is a block diagram showing the signal line connection state of the main parts in the first batch. 1.9... Composite video signal 2 output from a TV tuner, video disc player, or video tape recorder 2 R, G, B signals output from a converter 3.11... Mode switching signal 4.12... Video Coordination processing circuit 5 ・7゛ analog matrix path 6 . . . Analog data selector circuit 7 . . . Video intensifier circuit 8.18 . I signal 13...Al1) Conversion circuit 1t...Digital matrix circuit 15...-j J4 combination circuit 16...Digital data selector circuit 17...D
/A conversion circuit and

Claims (1)

[Claims] 1) A video signal processing circuit that processes a video signal from a video signal generation source and outputs a luminance signal and a color difference signal, and A that converts the luminance signal and color difference signal from analog quantities to digital quantities.
A /D conversion circuit, a digital matrix circuit that converts the digital luminance signal and color difference signal from the conversion circuit into three primary color signals, and outputs the three primary color signals, and the digital three primary color signals and brightness designation data from the character/figure signal generation source are input. a combinational circuit that outputs digital three primary color signals containing luminance information; and a combinational circuit that receives the digital three primary color signals from the digital matrix circuit and those from the combinational circuit, and selects one of them according to a command, or both. 1. A superimpose circuit comprising: a selector circuit that superimposes and outputs a superimposed image, and outputs an output from the selector circuit toward a display device.