JPH03265293A - External input circuit for television receiver - Google Patents

Abstract

PURPOSE:To attain high picture quality with simple configuration by mixing an inputted luminance signal and chroma signal with respect to a separate signal of a standard signal given from an external device so as to generate a composite video signal thereby applying high picture quality processing. CONSTITUTION:A luminance signal and a chroma signal of a separate signal given from an external device via input terminals 13, 17 are given respectively to an encoder 16 via A/D converters 14, 18. The circuit 16 mixes the inputted luminance signal and chroma signal to form a composite video signal. Then in the case of the separate signal of the standard signal, the composite video signal from the circuit 16 is given to a video signal processing circuit 22 via a switch 15 in response to a switch control signal from a nonstandard signal detection circuit 31 and composite/separate non-signal detection circuits 32, 33. Thus, the separate signal of the standard signal is subjected to high picture quality with simple configuration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an external input circuit for a television receiver that processes composite video signals, brightness signals, and chroma signals input from the outside.

[Prior Art] For example, a high-definition television receiver (EDT) can process and display a composite video signal provided from an external device. The brightness signal and chroma signal (hereinafter sometimes referred to as separate signals) can be processed and displayed. A conventional external input circuit configuration for receiving and receiving composite video signals, luminance signals, and chroma signals is shown.

In Fig. 3, the composite video signal input from the external input terminal l is switched twice in a two-person, one-output configuration!
#! is applied to one input terminal of 2.

The luminance signal input from the external input terminal 3 is given to the other input terminal of the switch circuit 2. The switch circuit 2 is supplied with an input mode signal as a switching control signal that instructs whether to select a composite video signal or an already separated luminance signal and chroma signal as an input video signal. When the input mode signal indicates a composite video signal, the composite video signal is selected, and when the input mode signal indicates a separate signal, the luminance signal is selected and applied to the analog/digital conversion circuit 4.

The composite video signal or luminance signal converted into a digital signal by this analog/digital conversion circuit 4 is applied to one input terminal of a video signal processing circuit 5 and a switch circuit 6 having a two-manufacturing one-output configuration. The video signal processing circuit 5 includes a motion-adaptive Y/C separator according to a three-dimensional comb filter method and a motion-adaptive vertical contour correction section, and includes Y/C separated and vertical contour-corrected luminance and chroma signals. Output. The luminance signal from this video signal processing circuit 5 is applied to the other input terminal of the switch circuit 6 described above.

The switch circuit 6 is given an input mode signal as a switching control signal, and when this input mode signal indicates a composite video signal, it selects the luminance signal from the video signal processing circuit 5 and converts it into a separate signal. , the signal from the analog/digital conversion circuit 4 (which is a luminance signal) is selected and output to the next stage circuit.

The chroma signal from the video signal processing diagram H5 is applied to one input terminal of a switch circuit 7 having a two-power output configuration. The other input terminal of the switch circuit 7 is supplied with a chroma signal inputted from the input terminal 8 and converted into a digital signal by the analog/digital conversion circuit 9. This switch circuit 7 is given an input mode signal as a switching control signal, and when this input mode signal indicates a composite video signal, it selects the chroma signal from the video signal processing circuit 5 and selects the chroma signal from the video signal processing circuit 5 to separate the chroma signal from the video signal processing circuit 5. When a signal is being specified, the chroma signal from the analog/digital conversion circuit 9 is selected and output to the next stage circuit.

In this way, in conventional circuits, when a composite video signal is input, it is converted into a digital signal, then Y/C separated, and the vertical contour corrected luminance signal and chroma signal are output to the next stage circuit, and the separated luminance signal is And when a chroma signal is input, it is converted into a digital signal and output as is to the next stage circuit.

[Problems to be Solved by the Invention] By the way, examples of devices that output a video signal after being separated into a luminance signal and a chroma signal include a laser disk player and a video tape recorder.

Depending on its operating mode, such a device may output a so-called standard signal of a video signal, or a so-called non-standard signal.

For example, a video signal obtained in a normal playback mode in a laser disc player is a standard signal, but a video signal obtained in a special playback mode is a non-standard signal.

Further, a video signal reproduced by a video tape recorder is a non-standard signal, but a video signal obtained by simply receiving and demodulating broadcast radio waves is a standard signal.

Therefore, high-definition television receivers are not only provided with composite video signals of standard or non-standard signals, but also separate signals of standard or non-standard signals (
luminance signal and chroma signal> may be provided.

As mentioned above, according to the conventional circuit, the composite video signal is processed by the video signal processing circuit 5 that performs Y/C separation and vertical contour correction with high precision, but the separate signal is processed by the video signal processing circuit 5 that performs Y/C separation and vertical contour correction with high precision. Therefore, the processing by the video signal processing port 1\i85 is not executed.

However, even for separate signals, highly accurate processing is required. Therefore, it is conceivable to provide a vertical contour correction circuit or the like for each luminance signal and chroma signal, but providing separate contour correction circuits for the composite video signal, luminance signal, and chroma signal would result in a complicated and large configuration. Also,
Although the luminance signal and the chroma signal are input separately, there is a possibility that the accuracy of the Y/C separation circuit in the device that sends out the separate signal is low, causing dot color or dot crawl in the separate signal. Therefore, even if they are input separately, it is required to improve the accuracy of the luminance signal and chroma signal in the high-definition television receiver.

By the way, in the case of non-standard signals, the correlation between consecutive horizontal scanning lines or between consecutive frames is not necessarily high due to fluctuations in the time axis and the like. Therefore, it is required to determine whether or not to apply image quality improvement processing using line correlation or frame correlation depending on whether the separate signal is a standard signal or a non-standard signal.

The present invention has been made in consideration of the above points, and it is possible to appropriately perform image quality enhancement processing on separate signals given from an external device and provide luminance signals and chroma signals to the next stage circuit. The purpose of this invention is to provide an external input circuit for a television receiver that can be used.

[Means for Solving the Problem] In order to solve the problem, in the present invention, a composite video signal, a luminance signal and a chroma signal that have already been separated are input from an external device, and any of the input In an external input circuit of a television receiver that outputs a luminance signal and a chroma signal to the next stage circuit even in a mode, an encoder means mixes the separately inputted luminance signal and chroma signal to form a composite video signal. and composite no-signal detection means for determining whether or not a composite video signal is input, and separate no-signal detection means for determining whether or not separated luminance and chroma signals are input. non-standard signal detection means for determining whether the input luminance signal and chroma signal are standard signals or non-standard signals; video signal processing means for performing high image quality processing with at least a built-in Y/C separator; and non-composite signal processing means. Based on the output signals from the signal detecting means, the separate no-signal detecting means, and the non-standard signal detecting means, if only a composite video signal is input from an external device, the composite video signal is given to the video signal processing means to process this video. The luminance signal and chroma signal from the signal processing means are output to the next stage circuit, and when only the standard signal luminance signal and chroma signal are input from an external device, the composite video signal from the encoder means is output to the video signal processing means. The luminance signal and chroma signal from this video signal processing means are output to the next stage circuit, and when only the luminance signal and chroma signal of the non-standard signal are input from an external device, the input luminance signal and chroma signal are and output control means for outputting the chroma signal to the next stage circuit.

Note that when a composite video signal, separated luminance signal, and chroma signal are input together from an external device, various output methods are possible, but if the input signal is a standard signal, Applying a composite video signal to a video signal processing means and outputting a luminance signal and a chroma signal from the video signal processing means to a next stage circuit;
If the input signal is a non-standard signal, it is preferable to output the luminance signal and chroma signal input from the external device to the next stage circuit. It is characterized by the way the signal and chroma signal are output to the next stage circuit.

In order to detect whether the input from the external device is a composite video signal or already separated luminance and chroma signals, a composite no-signal detection means and a separate no-signal detection means are provided. Further, non-standard signal detection means is provided to determine whether a signal from an external device is a standard signal or a non-standard signal. These output signals are
Used to control the output to the next stage circuit.

Further, encoder means for forming a composite video signal from the input luminance signal and chroma signal;
A video signal processing means is provided for performing high image quality processing including at least separation processing of composite video signals.

The output control means converts the composite video signal into a video signal based on the output signals from the composite no-signal detection means, the separate no-signal detection means, and the non-standard signal detection means, when only the composite video signal is input from an external device. The video signal processing means outputs the luminance signal and chroma signal from the video signal processing means to the next stage circuit, and when only the standard signal luminance signal and chroma signal are input from an external device, the composite signal from the encoder means The video signal is given to the video signal processing means, and the luminance signal and chroma signal from the video signal processing means are output to the next stage circuit, and when only the luminance signal and chroma signal of the non-standard signal are input from the external device, , outputs the input luminance signal and chroma signal to the next stage circuit.

Thereby, high image quality processing can be applied to standard signals such as luminance signals and chroma signals from an external device.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, a composite video signal applied from an external device via an input terminal 10 is converted into a digital signal via an analog/digital conversion port 11, and then converted into a digital signal via an analog/digital conversion port 11.
It is applied to the (2)th input terminal of the switch circuit Fl@12 which has a single output configuration.

Further, the luminance signal of the separate signal given from the external device via the input terminal 13 is converted into a digital signal via the analog/digital conversion circuit 14, and after fS, the second input terminal of the above-mentioned switch circuit 12, Two manual inputs (supplied to the first input terminal of the switch circuit 15 in the output configuration and to the encoder circuit 1N16).

Further, the chroma signal of the separate signal applied from the external device via the input terminal 17 is converted into a digital signal via the analog/digital conversion circuit 18, and then the chroma signal is converted into a digital signal via the analog/digital conversion circuit 18. 1 input terminal,
and is applied to the encoder circuit 16.

The encoder circuit 16 mixes the input luminance signal and chroma signal to form a composite video signal, and sends the formed composite video signal to the switch circuit 1 described above.
5 to the second input terminal.

The switch circuit 12 includes a switch control circuit 30 which will be described later.
When the switch control signal SL is logic "1", the composite video signal from the analog/digital conversion circuit &'J11 is selected, and when the switch control signal SL is logic "O", the analog/digital conversion is performed. circuit 14
Select the luminance signal from. The selected composite video signal or luminance signal is applied to a first input terminal of a switch circuit 20 having a two-power output configuration.

The switch circuit 15 includes a switch control circuit 30 which will be described later.
When the switch control signal S2 is logic "1", the formed composite video signal from the encoder circuit 16 is selected, and the logic r□,
At this time, the luminance signal from the analog/digital conversion circuit 14 is selected.

The selected composite video signal or luminance signal is applied to the second input terminal of the switch circuit 20.

The switch circuit 20 also includes a switch control circuit 30 which will be described later.
A switch control signal S3 is applied from logic r1. , the signal from the switch circuit 12 is selected, and the signal from the switch circuit 15 is selected when the logic is "O".
Select the signal from.

The selected signal is sent to the switch circuit 2 of the two-manufacturing i-output configuration.
1 and the video signal processing circuit 22. The video signal processing circuit 22 includes a motion-adaptive Y/C separator according to a three-dimensional comb filter method and a motion-adaptive vertical contour correction section. Output a signal. The luminance signal from this video signal processing circuit 22 is applied to the second input terminal of the switch circuit 21, and the chroma signal is applied to the second input terminal of one switch circuit.

These switch circuits 21 and 19 are also supplied with a common switching control signal S4 from a switch circuit 30, which will be described later, and these switch circuits 21 and 19 switch in conjunction with each other. When the switch control signal S4 is logic "1", the switch circuit 2■ selects the signal from the switch circuit 20 (in this case, the luminance signal as described later), and the switch circuit 1￥819 selects the signal from the switch circuit 20, and the switch circuit 1￥819 selects the signal from the switch circuit 20. Selects the remaining chroma signals and supplies them to the next stage circuit. When the switch control signal S4 is logic "O", the switch circuit 2
1 and 19 select the luminance signal and chroma signal from the video signal processing circuit 22, respectively, and apply them to the next stage circuit.

The switch control circuit 830 that outputs the above-mentioned switch control signals Sl to S4 includes an analog/digital conversion circuit 11.
A composite video signal from the analog/digital conversion circuit 14 and a luminance signal from the analog/digital conversion circuit 14 are applied, and each switch control signal 81 to S4 is formed based on these signals.

The switch control circuit 30 includes a non-standard signal detection circuit 31,
Composite no-signal detection circuit 32, separate no-signal detection circuit 33, exclusive NOR circuit 34, OR circuit 35, inverter circuit 36, AND circuit 37
It is made up of spikes.

A luminance signal from the analog/digital conversion circuit 14 is given to the non-standard signal detection circuit 31 . The non-standard signal detection port 131 detects whether the separate signal or the non-standard signal is a standard signal based on this luminance signal, and outputs logic "O" when the signal is a non-standard signal, and logic r1. when the signal is a standard signal. A detection signal Kl, which takes the value, is applied to the switch circuit 15 as a switch control signal S2, and is also applied to the two-person chaor circuit 835 and the inverter circuit 36. Even when no separate signal is input, the non-standard signal detection circuit 31 is set to logic “0”.
A detection signal Kl is output.

A composite video signal from the analog/digital conversion circuit 11 is applied to the composite no-signal detection circuit 32 . The composite no-signal detection circuit 32 outputs a logic "0" when the composite video signal is not input, and a logic "1" when the composite video signal is input.
is applied to the switch circuit 120 as the switch control signal S3, and also to the two-person exclusive Noah circuit 834.

The separate no-signal detection circuit 33 is given a luminance signal from the analog/digital conversion circuit 14 . The separate no-signal detection circuit 33 detects the luminance signal (separate signal)
A detection signal of 3 is applied to the exclusive NOR circuit 34 and the AND circuit 37, which takes a logic "0" when the signal is not input, and a logic "1" when the signal is input.

The signal from the exclusive NOR circuit 34 is the OR circuit 3
The output signal from the OR circuit 35 is applied to the switch circuit 12 as a switch control signal SL.

Further, the signal from the inverter circuit 36 is transmitted to the AND circuit 137.
The signal from the AND circuit 37 is applied to the switch circuits 21 and 19 as a switch control signal S4.

Therefore, the relationship between the logic of 1 to 3 in the detection signals from each of the detection circuits 3-33 and the logic of each switch control signal 81-S4 is as shown in the truth table of FIG.

The reason why the switch control signals 81 to S4 having the logic shown in FIG. 2 are formed from the detection signals Kl to 3 is based on the following idea.

If only a composite video signal is input without a separate signal, the input composite video signal is given to the video signal processing circuit 22, regardless of whether the composite video signal is a non-standard signal or a standard signal. The video signal processing circuit 22 outputs the luminance signal and chroma signal to the next stage circuit. In the case of non-standard signals, line correlation and frame correlation are not sufficient, but since no separate signals are input, this processing is the only option.

When only a separate signal is input without a composite video signal, the processing method changes depending on whether the separate signal is a non-standard signal or a standard signal. If the signal is a standard signal, a composite video signal obtained by mixing the input luminance signal and chroma signal is given to the video signal processing circuit 822 for processing, and the luminance signal output from the video signal processing circuit 22 is processed. and output the chroma signal to the next stage circuit. On the other hand, if the signals are non-standard, the input luminance signal and chroma signal are output as they are to the next stage circuit.

Note that analog/digital conversion has been performed.

The reason why the processing is performed differently depending on whether the signal is a standard signal or a non-standard signal is as follows.

Even if the luminance signal and chroma signal are input separately,
Since the video signal processing circuit 22 performs image quality enhancement processing, in the case of a standard signal, passing the signal through this circuit 22 improves the image quality. However, in the case of non-standard signals,
Since the line correlation and frame correlation are insufficient, no improvement in image quality can be expected even through the video signal processing circuit 22, and the image quality may deteriorate instead. Therefore, in this case, it was decided to output the input luminance signal and chroma signal as they are.

Even when a composite video signal and a separate signal are input together, the processing method differs depending on whether the signal is a non-standard signal or a standard signal. If it is a standard signal, convert the input composite video signal to video signal processing diagram #I2.
2 for processing, and the luminance signal and chroma signal output from this video signal processing circuit 22 are output to the next stage circuit. On the other hand, if the signals are non-standard, the input luminance signal and chroma signal are output as they are to the next stage circuit.

The reason why this control is performed in the case of a non-standard signal is the same as the reason when only a separate signal of the non-standard signal is input.

In the case of a standard signal, it is conceivable to give a composite video signal obtained by combining separate input luminance signals and chroma signals to the video signal processing circuit 22 and output the output luminance signal and chroma signal, but as described above, The input composite video signal is processed by the video signal processing circuit 2.
2 and output the output luminance signal and chroma signal to the next stage circuit for the following reason. When mixing luminance signals and chroma signals, it is affected by quantization errors, etc., and the resulting composite video signal has more noise components than the input composite video signal due to the mixing process. Therefore, it was decided to provide the input composite video signal to the video signal processing circuit 22.

Therefore, according to the above-mentioned embodiment, even if a separate signal is input, if it is a standard signal, it is processed by the video signal processing port 122 that performs high-image quality processing, so that high image quality can be achieved. The luminance signal and chroma signal can be provided to the next stage circuit.

Note that although the above description shows a system that determines whether a standard signal or a non-standard signal is applied only to separate signals, this determination can also be performed for composite video signals, and the results can also be used to determine the processing method. You may try changing it.

In this case, cases in which both a separate signal and a composite video signal are input are more finely divided than in the embodiment.

Furthermore, when both a composite video signal and separated luminance and chroma signals are input, an output method different from that of the above embodiment may be adopted. For example, in order to simplify the configuration, processing may be performed in the same manner as when only separate signals are input.

Further, the video signal processing circuit may be any circuit as long as it includes at least an adaptive Y/C separation section.

[Effects of the Invention] As described above, according to the present invention, when a separate signal of a standard signal is input, it is processed by a video signal processing circuit that performs high-quality processing, thereby achieving high image quality. The brightness signal and chroma signal that can be obtained can be given to the next stage circuit.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the external input circuit of a television receiver according to the present invention, Fig. 2 is a diagram showing a truth table for explaining the operation of each part, and Fig. 3 shows a conventional circuit. It is a block diagram. 11.14.18...Analog/digital conversion circuit,
12.15, ■9~2■...Switch circuit, ■6...
- Encoder circuit, 22...Video signal processing circuit, 3
0... Switch control circuit, 31... Non-standard signal detection circuit, 32... Composite no-signal detection circuit, 33.
... Separate no-signal detection circuit, 34 ... Exclusive NOR circuit, 35 ... OR circuit, 36 ... Inverter circuit, 37 ... AND circuit.

Claims (2)

[Claims] (1) A television that receives a composite video signal, already separated luminance signal, and chroma signal from an external device, and outputs the luminance signal and chroma signal to the next stage circuit regardless of the input mode. an encoder means for forming a composite video signal by mixing the separated input luminance signal and chroma signal; and a composite no-signal detection for determining whether or not the composite video signal is input, in the external input circuit of the television receiver separate no-signal detection means for determining whether or not the separated luminance signal and chroma signal are input; and at least determining whether the separated input luminance signal and chroma signal are standard signals or non-standard signals. a video signal processing means incorporating at least a Y/C separation unit and performing high-image quality processing; the composite no-signal detection means, the separate no-signal detection means, and the non-standard signal detection means. When only a composite video signal is input from an external device, the composite video signal is given to the video signal processing means, and the luminance signal and chroma signal from this video signal processing means are sent to the next stage circuit. When only the standard signal luminance signal and chroma signal are input from an external device, the composite video signal from the encoder means is supplied to the video signal processing means to output the luminance signal from the video signal processing means. and output control means for outputting the input luminance signal and chroma signal to the next stage circuit when only the non-standard luminance signal and chroma signal are input from an external device. An external input circuit for a television receiver, comprising: (2) When a composite video signal, a separated luminance signal, and a chroma signal are both input from an external device, the output control means determines that the input signal is a standard signal and outputs the input composite video signal. is applied to the video signal processing means to output the luminance signal and chroma signal from the video signal processing means to the next stage circuit, and if the input signal is a non-standard signal, the luminance signal and chroma signal input from the external device are 2. The external input circuit for a television receiver according to claim 1, wherein the external input circuit for a television receiver outputs the signal to a next-stage circuit.