JPH05292536A - Automatic picture quality adjusting device - Google Patents

Abstract

PURPOSE:To enable a user to see a color video picture in natural white and hue under any illumination without troubling him. CONSTITUTION:This device is provided with color temperature detecting means 1R, 1G, and 1B which detect the color temperature of external light, a video signal processing circuit 2 which outputs red, green, and blue video signals, and a color temperature setting circuit 3 which adjusts respective signal levels of red, green, and blue video signals outputted from the video signal processing circuit 2 based on color temperature information detected by color temperature detecting means 1R, 1G, and 1B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic image quality adjusting device suitable for use in a color television receiver, a color video monitor, a color rear projector and the like.

[0002]

2. Description of the Related Art In general, white light having the same color temperature displayed on an image screen of a color television receiver, a color video monitor, or the like also illuminates a place where the user is watching (including natural light). ), The impression will be different depending on the color temperature.

However, in a conventional color television receiver or the like, even if the color temperature is fixed or has a color temperature adjusting function, the color temperature is manually adjusted by the user. For this reason, there is an inconvenience that the user is presented with an unnatural white or shaded color image screen depending on the illumination of the place being viewed.

In view of the above problems, an object of the present invention is to allow a user to view a color image screen in a natural white color or shade under any lighting without bothering the user.

[0005]

As shown in FIG. 1, for example, the automatic image quality adjusting apparatus of the present invention includes color temperature detecting means 1R, 1G and 1B for detecting the color temperature of external light and red, green and blue image signals. Of the red, green and blue video signals output from the video signal processing circuit 2 based on the color temperature information detected by the color temperature detecting means 1R, 1G and 1B. The color temperature setting circuit 3 for adjusting each signal level is provided.

The automatic image quality adjusting apparatus of the present invention is shown in FIG.
As described above, the color temperature detecting means 1R, 1G,
The image signal processing circuit 2 is provided with an image contrast adjusting circuit 2a for controlling the screen brightness according to the ambient brightness based on the color temperature information detected by 1B.

[0007]

According to the present invention, the color temperature of external light is detected, and the signal levels of the red, green, and blue video signals are adjusted based on this color temperature information. You can view a color video screen with natural white and shades under any lighting without any trouble.

Further, according to the present invention, the color temperature detecting means 1
Since the ambient brightness can be measured with R, 1G, and 1B, the function of adjusting the screen brightness according to the ambient brightness can be combined with the above to realize a color image screen with a natural hue that is easier to see. You can

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the automatic image quality adjusting device of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 2 denotes a video signal processing circuit. The video signal processing circuit 2 is supplied with a color video signal such as a reception signal of a television broadcast signal or a reproduction signal from a video tape recorder, and decodes this color video signal. Then, the three primary color signals of the red video signal R, the green video signal G and the blue video signal B are obtained on this output side.

In this example, a video contrast adjusting circuit 2a for controlling the screen brightness according to the ambient brightness by a contrast control signal described later is provided in the video signal processing circuit 2.

A red video signal R, a green video signal G and a blue video signal B obtained at the output side of the video signal processing circuit 2.
The gain control amplifiers 3R and 3G each have a color temperature setting circuit 3 whose gain is controlled by a color temperature control signal described later.
And 3B to supply them to the color cathode ray tube 4, respectively, so that a color image screen is obtained by this color cathode ray tube 4.

Further, in FIG. 1, reference numerals 1R, 1G and 1B denote red, green and external light (for example, light around the television receiver) to which external light is supplied via a red filter 5R, a green filter 5G and a blue filter 5B, respectively. Shown is a blue light sensor, which is a red, green and blue light sensor 1R, 1G and 1B.
The red, green and blue detection signals corresponding to the respective external light intensities are supplied to the interface circuit 6, respectively.

In this interface circuit 6,
The color temperature of the external light is detected by the ratio of the magnitudes of the red, green and blue detection signals of the external light, and the red, green and blue video signals R, G and B corresponding to the color temperature of the external light are obtained. Such a color temperature control signal is supplied to the color temperature setting circuit 3, the gains of the gain control amplifiers 3R, 3G and 3B constituting the color temperature setting circuit 3 are controlled, and red and green supplied to the color cathode ray tube 4 are supplied. And the levels of the blue video signals R, G and B are controlled.

In the interface circuit 6, the red, green and blue detection signals are summed or averaged to detect the brightness of the external light, and the brightness of the external light (ambient brightness) is detected. Then, the contrast control signal is obtained, and this contrast control signal is supplied to the image contrast adjusting circuit 2a of the image signal processing circuit 2 so that the brightness of the screen is controlled according to the ambient brightness.

The interface circuit 6 can be configured by hardware, but can also be configured by software processing by a microcomputer.

As described above, this embodiment detects the ambient brightness (external light) of a television receiver, for example, and based on the color temperature of this external light, the signal levels of the red, green and blue video signals. Therefore, there is an advantage that a color image screen can be viewed in a natural white or a hue under any lighting without any trouble of the user.

Further, according to this embodiment, the ambient light of the television receiver can be measured by the optical sensors 1R, 1G, 1B for detecting the color temperature of the external light. The brightness of the image screen can be adjusted, and by combining this image contrast adjustment function and the function to obtain a color image screen with a natural white or shade depending on the color temperature of the above-mentioned external light, it is possible to obtain a natural hue that is easier to see. There is a benefit that can realize a color video screen.

In the color temperature setting circuit 3 of the example of FIG. 1, the gain control amplifiers 3R, 3G and 3B are described as controlling the gains respectively, but one gain of these three gain control amplifiers is fixed, Even if the other two are controlled, the same effect as described above can be obtained. For example, as shown in FIG. 2, the gain of the gain control amplifier 3G that amplifies the green video signal is fixed, and other red video signals and blue video signals are obtained. The gains of the gain control amplifiers 3R and 3B for amplifying the signals may be adjusted.

Further, in the above-mentioned embodiment, an example using a color cathode ray tube was described, but the present invention can be applied to a rear projector using a color cathode ray tube, a rear projector using a color liquid crystal display device, and the like. Of course. Further, the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0020]

According to the present invention, there is an advantage that the user can view a color image screen with a natural white color or shade under any lighting without bothering the user.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic image quality adjustment device of the present invention.

FIG. 2 is a configuration diagram showing another example of a color temperature setting circuit.

[Explanation of symbols]

 1R, 1G, 1B optical sensor 2 video signal processing circuit 3 color temperature setting circuit 4 color cathode ray tube 5R, 5G, 5B color filter 6 interface circuit

Claims (2)

[Claims] 1. A color temperature detecting means for detecting a color temperature of external light, a video signal processing circuit for outputting red, green and blue video signals, and based on color temperature information detected by the color temperature detecting means. And a color temperature setting circuit for adjusting each signal level of the red, green and blue video signals output from the video signal processing circuit. 2. A video contrast adjusting circuit for controlling the brightness of the screen according to the ambient brightness based on the color temperature information detected by the color temperature detecting means is provided in the video signal processing circuit. The automatic image quality adjusting device according to claim 1.