JP2000078470A - Automatic control circuit for superimposed character luminance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a character easy to read by controlling the luminance of a character to be superimposed corresponding to the luminance of the moving background video in the case of a communication KARAOKE or the like. SOLUTION: The average luminance of a luminance signal Y separated from a moving background video signal 2 by a Y/C separating circuit 3 is calculated by an average luminance calculating part 4. Based on this average luminance of the moving background image, a value for making the character to be superimposed into luminance easy to watch is read out of a control table 5. Corresponding to this read value, the luminance of character RGB signals is controlled by a gain control amplifier 7. Then, the moving background video signal converted to RGB signals by and RGB decode circuit 8 and the luminance controlled character RGB signals are superimposed by a compositing circuit 9 and converted to signals in NTSC format by an NTSC encoder 10. Thus, even when the moving background video is changed, the character to be superimposed can be made easy to watch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superimposed character luminance automatic adjustment circuit for automatically adjusting the luminance of a superimposed character to a luminance that is easy to see in accordance with the luminance of a background moving image.

[0002]

2. Description of the Related Art Conventionally, when characters such as lyrics are superimposed on a background moving image video in karaoke or the like, in order to make the characters easier to read, characters of a fixed brightness are fixed to several types for each song. Have been used.

[0003]

However, in recent communication karaoke, a background moving image is not fixed by a song, and a number of background moving images are selected as backgrounds for exactly the same song. At this time, for example, when a background moving image with low luminance is displayed when the luminance of the character is low, the character becomes difficult to read. Similarly, when a background moving image with high brightness is displayed when the brightness of the character is high, the character becomes difficult to read.

The present invention has been made in view of such circumstances, and has as its object to provide a superimposed character brightness automatic adjustment circuit which makes it easy to read characters superimposed on a background moving image.

[0005]

According to the present invention, there is provided a circuit for automatically adjusting the luminance of a character superimposed on a background moving picture image, wherein the luminance signal is separated from the background moving picture image signal. Means for controlling the luminance of the character signal based on the luminance signal; and synthesizing the image signal based on the background moving image signal and the character signal controlled by the control means so that the character is superimposed on the background image. A superimposed character brightness automatic adjustment circuit comprising: a video signal forming means for forming a reproduced video signal.

According to a second aspect of the present invention, there is provided a circuit for automatically adjusting the luminance of a character superimposed on a background moving image, comprising: a separating unit for separating a luminance signal from a background moving image signal; Average luminance calculating means for calculating average luminance data of the background moving image based on the luminance signal, a gain control table for receiving average luminance data and outputting gain control data corresponding to the luminance data, and a character signal. A gain control amplifier that amplifies and outputs the character signal with a gain determined by the gain control data, and combines an image signal based on a background moving image signal with the output of the gain control amplifier to superimpose characters on the background image. Video signal forming means for forming a paused video signal. A par imposed letter automatic brightness adjustment circuit.

According to a third aspect of the invention, in the superimposed character brightness automatic adjusting circuit according to the second aspect, the characteristics of the brightness adjustment of the character can be changed by rewriting the contents of the gain control table from an external controller. It is characterized by doing so.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A superimposed character brightness automatic adjustment circuit according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a superimposed character brightness automatic adjustment circuit according to the first embodiment. In this figure, reference numeral 3 denotes a Y / C for inputting a background moving image video signal 2 in the NTSC format and separating it into a luminance signal Y and a color signal C.
The separation circuit 4 is an average luminance calculation unit that receives the luminance signal Y and calculates the average luminance of the screen.

Reference numeral 5 denotes a gain control table in which a table value for adjusting a character to be easily viewable based on the average luminance value is stored in advance. Reference numeral 7 denotes a gain corresponding to the table value output from the gain control table 5. R signal, G that constitutes character RGB signal 6 input from outside
It is a gain control amplifier that amplifies signals and B signals and outputs them as R, G and B signals. 8
Is a RGB signal which receives the luminance signal Y and the color signal C of the background moving image signal 2 and converts them into R, G, and B signals.
The decoding circuit 9 is an R signal, a G signal, and a B signal of the background moving image.
A synthesizing circuit 10 for superimposing the R signal, the G signal, and the B signal of the signal and the character is an NTSC encoder 10 for converting the superimposed R, G, and B signals into NTSC format signals.

Next, the operation of the superimposed character brightness automatic adjustment circuit 1 will be described. When the background video signal 2 is input to the Y / C separation circuit 3, the Y / C separation circuit 3 separates the background video signal 2 into a luminance signal Y and a color signal C,
The luminance signal Y is output to the luminance average calculation section 4. The luminance average calculation unit 4 calculates the average luminance per frame of the entire screen of the background moving image video signal 2 from the input luminance signal Y,
The calculated average luminance is output to the gain control table 5.

The gain control table 5 is a table for determining an optimum table value for making the luminance of the background moving image easy to see based on the input average luminance. The gain of the gain control amplifier 7 is determined by the table value. Specifically, the gain control table 5
Is a value that decreases the luminance of the character R, G, and B signals output from the gain control amplifier 7 when the average luminance of the luminance signal Y of the background moving image is high.

Conversely, when the average luminance of the luminance signal Y of the background moving image is low, the luminance R, G, and B signals output from the gain control amplifier 7 have values that increase the luminance. The gain control amplifier 7 adjusts the luminance of the character R signal, G signal, and B signal according to the table value input from the gain control table 5 and outputs the result as character R, G, and B signals. Then, the character R, G, and B signals output from the gain control amplifier 7 are input to the synthesis circuit 9.

On the other hand, the Y / C separated luminance signal Y and color signal C of the background moving image are converted into R, G, and B signals by an RGB decoding circuit 8 and input to a synthesizing circuit 9. The synthesizing circuit 9 superimposes the R, G, B signals and the R, G, B signals from the gain control amplifier 7. Then, the superimposed R signal, G signal, and B signal are converted into NTSC format signals by the NTSC encoder 10 and output.

Next, another embodiment to which the present invention is applied will be described with reference to FIG. In FIG. 2, FIG.
The same parts as those described above are denoted by the same reference numerals and description thereof will be omitted.
In the embodiment of FIG. 2, the contents of the gain control table 5 in the embodiment of FIG.
Can be overwritten. This makes it possible to externally rewrite the contents of the gain control table 5 and change the character brightness adjustment characteristics as needed.

[0015]

As described above, according to the present invention, characters can be displayed at an appropriate luminance according to the luminance of the background image, and a character display that is much easier to read than before can be performed. it can.

According to the third aspect of the present invention, by rewriting the contents of the gain control table from the external controller, it is possible to obtain the effect of optimally changing the luminance adjustment characteristics of characters.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a superimposed character brightness automatic adjustment circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a superimposed character brightness automatic adjustment circuit according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Superimposed character brightness automatic adjustment circuit 2 ... Background video image signal 3 ... Y / C separation circuit 4 ... Average brightness calculation unit 5 ... Gain control table 6 ... Character RGB signal 7 ... Gain control amplifier
8 RGB decoding circuit 9 Synthesis circuit 10 NTSC
Encoder 12 ... External controller

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeshi Matsumoto 1-1-1, Shinurashima-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in NEC Robot Engineering Co., Ltd. EA01 5C025 AA28 BA16 BA28 CA09 DA08 5C082 AA02 BA02 BA34 BA35 BA41 BB51 CA11 CA59 CB01 DA71 MM10

Claims (3)

[Claims] 1. A superimposed character luminance automatic adjustment circuit for automatically adjusting the luminance of a character superimposed on a background moving image video, comprising: a separating unit for separating a luminance signal from the background moving image signal; Control means for controlling the luminance of the character signal based on the image signal based on the background moving image signal and the character signal controlled by the control means, and forming a video signal in which the character is superimposed on the background image. A superimposed character brightness automatic adjustment circuit, comprising: 2. A superimposed character brightness automatic adjustment circuit for automatically adjusting the brightness of a character superimposed on a background moving image, comprising: a separating unit for separating a luminance signal from the background moving image signal; Average luminance calculating means for calculating the average luminance data of the background moving image based on the luminance signal, a gain control table receiving the average luminance data and outputting gain control data corresponding to the luminance data, and a character signal. And a gain control amplifier for amplifying and outputting the character signal with a gain determined by the gain control data, and combining an image signal based on the background moving image signal with the output of the gain control amplifier to convert the character into a background image. Video signal forming means for forming a superimposed video signal; A superimposed character brightness automatic adjustment circuit, comprising: 3. The superimposed character brightness automatic adjustment circuit according to claim 2, wherein the content of the gain control table is rewritten from an external controller so that the characteristics of the character brightness adjustment can be changed. .