JPH0718221Y2 - Digital television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of Invention] (Field of Industrial Application) The present invention relates to a digital television receiver in which luminance signal processing and chromaticity signal processing are performed digitally.

(Prior Art) FIG. 5 shows a configuration of a so-called digital television receiver in which a luminance signal (hereinafter referred to as Y signal) processing circuit and a chromaticity signal (hereinafter referred to as C signal) processing circuit portion are digitized. . In FIG. 5, an analog composite video signal is input from an analog digital (hereinafter referred to as A /
It is supplied to the converter 2 and is converted into a digital composite video signal. This digital composite video signal is supplied to a luminance / chromaticity (hereinafter referred to as Y / C) separation circuit 3 and separated into a Y signal and a C signal. The Y signal is a Y signal processing circuit 4 and the C signal is a chroma band pass filter. 5 is supplied.

The Y signal processing circuit 4 corrects the image quality or the contrast, and the output thereof is returned to an analog Y signal by a digital-analog (hereinafter referred to as D / A) converter 7. On the other hand, the C signal component extracted by the chroma band pass filter 5 is demodulated to a color difference signal by the color signal processing circuit 6, and this color difference signal is returned to an analog color difference signal by the D / A converter 8.

These analog Y signal and color difference signal are supplied to a matrix circuit 9, and the matrix circuit 9 obtains R, G, B primary color signals by a matrix operation.

By the way, generally, in a television receiver, for example, the ratio between the level of the luminance signal and the level of the chromaticity signal is adjusted so that the human's dark color approaches a natural color. Since the body color is reproduced by the color reproduction characteristics of the picture tube and the level ratio sent from the broadcasting station, it can be adjusted according to the user's preference.

(Problems to be solved by the invention) However, in the conventional system, the adjustment target is limited to a specific color such as a body color, and even if this color is reproduced well, other colors are not reproduced. However, they do not always improve at the same time. For example, if the C signal level is fixed and the Y signal level is increased, the whole screen becomes whitish and the color fades, and if the Y signal level is decreased, the color appears harsh.

Next, consider a video signal sent from a broadcasting station. Assuming white is Y signal 100% and black is Y signal 0%,
Looking now at a video signal of a human face, the Y signal corresponding to the deep color portion is about 60%. However, the Y
When the signal is set to about 70%, it may become more whitish and pinkish and may be close to natural. Performing this adjustment raises the Y signal level, but at the same time, the black portion also fades and becomes closer to gray, and the natural feeling of the other colors excluding the wasted color fades.

Therefore, an object of the present invention is to provide a digital television receiver capable of solving the problem that the color tone of other portions is deteriorated when the color tone is partially adjusted as described above with a simple configuration. Is.

[Constitution of device]

(Means for Solving the Problems) In this invention, the digital Y signal line is provided with a non-linear processing means.

(Operation) By providing the non-linear processing circuit, the Y signal level can be brought closer to the adjustment state corresponding to each color portion, rather than being entirely adjusted to adjust the color tone of a part, and the whole screen can be displayed naturally. Color feeling can be improved.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
The figure is an embodiment of the present invention, in which an analog composite video signal is input through an input terminal 1 to an A / D converter 2
Is supplied to. The A / D converter 2, Y / C separation circuit 3, Y signal processing circuit 4, chroma bandpass filter 5, color signal processing circuit 6, D / A converters 7, 8 and matrix circuit 9 are shown in FIG. There is no difference from the conventional one. Therefore, the same numbers as in FIG.

In the case of this invention, the Y signal processing circuit 4 and the D / A converter 7
A characteristic is that a non-linear circuit 10 is provided on the Y signal line between them, and the non-linear processing of the Y signal is provided by this circuit.

As the above-mentioned non-linear circuit 10, for example, a read-only memory (hereinafter referred to as ROM) that stores function data is used. The ROM outputs the data written in the address when the address is designated, and is used in the form of inputting the Y signal to the address line of the ROM as shown in FIG. Therefore, an arbitrary function f is used as ROM data.
By writing the data indicating (x), a non-linear output with respect to the linearity of the input can be obtained as shown in FIG. By doing so, for example, when a Y signal of a level corresponding to a dark color arrives, the level is raised, and when a Y signal of a level corresponding to another color arrives, the level is output as it is. In addition, the color tone can be partially corrected, and the color tone of other parts is not impaired. Also, there are various modes of non-linear functions depending on the subject,
It is also possible to modify the Y signal at multiple level positions. This circuit does not add any complexity to the system even if it is done in this way. For example, the nonlinear characteristic can be freely selected by the switch 10A as shown in FIG. Can be achieved.

[Effect of device]

As described above, the present invention can provide a digital television receiver in which the digital luminance signal is nonlinearly processed by a simple configuration and the degree of freedom of adjustment is expanded without impairing the color tone.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the non-linear circuit of FIG. 1, FIG. 3 is a diagram showing an example of non-linear characteristics, and FIG. Figure showing an example of
FIG. 5 is a block diagram of a conventional digital television receiver. 2 ... Analog-digital converter, 3 ... Luminance / chromaticity separation circuit, 4 ... Luminance signal processing circuit, 7,8 ... Digital-analog converter, 10 ... Non-linear processing circuit.

Claims (1)

[Scope of utility model registration request] 1. In a digital television receiver for digitally processing a luminance signal and a chromaticity signal, a digital luminance signal line is raised and output when the digital luminance signal has a level corresponding to a specific color. , A digital television receiver characterized by being provided with a non-linear processing circuit for outputting as it is when the level is equivalent to other colors.