JPH03157073A - Two-screen television receiver - Google Patents

Abstract

PURPOSE:To obtain a slave screen with high picture quality by providing a video signal input terminal for master screen, a 1st A/D converter, a movement detection circuit and a YC separator circuit connecting to an output terminal of the 1st A/D converter, a slave screen video signal input terminal, a 2nd A/D converter and a 1st selection circuit switching an output signal of the YC separator circuit and an output signal of the 2nd A/D converter. CONSTITUTION:A YC separator circuit 30 outputs a signal processed between lines in the case of a moving picture depending on the output of a movement detection circuit 18 and outputs a signal processed between frames in the case of a still picture. A selection circuit 31 selects an output of the YC separator circuit 30 subject to movement adaptation when the master screen and the slave screen are the same and one input is enough for the processing as the channel search or the like and selects a video signal inputted to a slave screen video signal input terminal 4 when two different inputs are required. Then the YC separator circuit 30 subject to movement adaptation and the selection circuit 31 are provided in the path of the master screen video signal, which selects an output of the YC separator circuit 30 and the video signal inputted to the slave screen video signal input terminal to select the signal for the slave screen video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is necessary when using a three-dimensional YC-separated main screen video signal as a child screen video signal, and also relates to a line memory used in a vertical interpolation filter circuit. This is a two-screen TV that can reduce the capacity of the sub-screen, which is necessary when reducing the size of the sub-screen vertically to 2, and can also remove cross color from the sub-screen video signal input as a video. It is related to.

Conventional technology In recent years, two-screen TVs have been equipped with high-quality sub-screens as TV receivers use frame memory to perform YC separation and double-density scanning line interpolation, and the trend toward higher image quality is increasing. It is considered important.

An example of the conventional two-screen television mentioned above will be described below with reference to the drawings.

5 to 7 are for explaining a conventional example.

First, FIG. 5 shows a block diagram of a conventional 2M screen television.

In FIG. 5, l is an input terminal for the main screen video signal. Reference numeral 2 denotes an analog-to-digital (hereinafter abbreviated as A/D) converter which digitizes the input main screen video signal. A motion detection circuit 18 detects whether the image is a moving image or a still image and outputs a motion signal.

Reference numeral 3 denotes a scanning line interpolation circuit which interpolates lines necessary for sequential scanning conversion at double speed in accordance with the output of the motion detection circuit 18. 4 is an input terminal for a small screen video signal. 5 is A/
A Di converter digitizes the video signal for the small screen. 6
is a vertical interpolation filter circuit. A line memory 16 delays the input signal by one horizontal scanning line period (hereinafter abbreviated as H) and outputs the delayed signal. 17 is an adder which outputs the average of the input sums. A horizontal interpolation filter circuit 7 interpolates data in the horizontal direction. 8 is a field memory, and 9 is a field memory for storing one screen of a sub-screen video signal.

10 is a main screen/child screen synthesis circuit, and 11 is a main screen/child screen synthesis circuit which inserts the video signal of the child screen into the video signal of the main screen. 12 is a double speed conversion circuit, and 13 is a double speed conversion circuit which doubles the data speed and completes the sequential scan conversion. 14 is a D/A converter that converts the video signal back into an analog signal;
Reference numeral 5 denotes an output terminal for a main screen sub-screen composite video signal.

FIG. 6 is a block diagram showing the configuration of an interpolation filter circuit in a luminance signal path for a child screen.

In FIG. 6, 191 is an input terminal for a child screen luminance signal, 6 is a vertical interpolation filter circuit, 7 is a horizontal interpolation filter circuit, and 201 is a luminance signal output terminal after interpolation. Vertical interpolation filter circuit 6. The horizontal interpolation filter circuit 7 operates in the same way as the one shown in FIG. 5, so it is given the same number. FIG. 7 is a block diagram showing the configuration of the interpolation filter in the color difference signal path for the child screen. In Figure 7, 192
2 is an input terminal for a child screen color difference signal, 7 is a horizontal interpolation filter circuit, and 202 is an output terminal for a color difference signal after interpolation.

The operation of the two-screen television configured as described above will be described below.

First, in the brightness signal path for the child screen, a brightness signal is input to the input terminal 4 for the child screen, and is converted into a digital signal by the A/D converter 5. The digitized luminance signal becomes a signal obtained by averaging the current signal and the IH-delayed signal in the vertical interpolation filter circuit 6. In the horizontal interpolation filter circuit 7,
Adds the current signal and several signals delayed by several times and outputs the result. The output of the horizontal interpolation filter circuit 7 is stored in the field memory 8 and the field memory 9, and is sent to the main screen small screen synthesis circuit 10. A main screen sub-screen synthesis circuit 11 inserts the sub-screen luminance signal into the main screen luminance signal. Double speed conversion circuit 12
The data rate is doubled in the single speed conversion circuit 13, and the sequential scan conversion is completed.

On the other hand, in the color difference signal path of the sub-screen video signal, the signal flow is the same as the luminance signal path, but the color difference signal is input to the input terminal 4, and it does not pass through the vertical interpolation filter circuit, but only in the horizontal interpolation filter circuit 7. pass through.

(Toshiba Shiview = Vol. 42, No. 12 "High-quality Digital Telepino Published December 1, 1986) The invention attempts to solve!I! TitleHowever, with the above configuration, (1)!! for the screen Since three-dimensional VC separation is not performed in the video signal path, the three-dimensional YC-separated video signal cannot be used as a sub-screen video signal.

(2) The storage capacity of the line memory used in the vertical interpolation filter circuit cannot be reduced.

(3) Since the child screen brightness signal always passes through the vertical interpolation filter circuit, the vertical resolution deteriorates when the vertical reduction rate of the child screen is %.

(4) Since the child screen color difference signal does not pass through the vertical interpolation filter circuit, cross color occurs when a video signal is input.

- had the following issues.

In view of the above problems, the present invention (1) utilizes a three-dimensional YC-separated video signal for a main screen as a video signal for a sub-screen to create a high-quality sub-screen. (2) Reduce the storage capacity of line memory. (3) Improve the vertical resolution when reducing the child screen to 2 in the vertical direction. (4) To provide a two-screen television capable of removing cross-colors from sub-screen images that occur during video input.

Means for Solving the Problems In order to solve the above problems, the two-screen television of the present invention includes: (]) a main screen video signal input terminal, a first A/D converter, and a first A/D converter. A motion detection circuit and a YC separation circuit connected to the output terminal of the converter, a video signal input terminal for a small screen, a second A/D converter, an output signal of the YC separation circuit, and a second A/D converter. This device includes a first selection circuit that switches the output signal of the converter.

(2) Also, calculate the average of the output of the time axis multiplexing circuit, the line memory, the time axis separation circuit, the output of the first selection circuit, and the output of the time axis separation circuit connected to the output terminal of the first selection circuit. It is equipped with a horizontal interpolation filter circuit.

(3) Also, a sub-screen brightness signal input terminal, a vertical interpolation filter circuit connected to the input terminal, a second selection circuit for switching between the input signal and the output signal of the vertical interpolation filter circuit, and a horizontal interpolation filter circuit. It has a configuration.

(4) Furthermore, the configuration includes a color difference signal input terminal for a child screen, a vertical interpolation filter circuit connected to the input terminal, a third selection circuit for switching between the input signal and the output signal of the vertical interpolation filter circuit, and a horizontal interpolation filter circuit. It is equipped with the following.

Effects The present invention has the above-described configuration. (1) When only one input is required, such as when the parent screen and the child screen are the same, the output of the motion-adapted YC separation circuit is used as the child screen video signal.

(2) When the vertical size of the child screen is reduced to 1/n, the speed of the video signal input to the line memory is reduced to 1/n, and the storage capacity is reduced to 1/n.

(3) When the vertical reduction rate of the child screen is 2, the vertical resolution of the child screen is not degraded by not passing the child screen brightness signal through the vertical interpolation filter circuit.

(4) The vertical interpolation filter circuit outputs the average of two adjacent lines, so when a video signal is input, if it passes through the vertical interpolation filter circuit, the color difference signal for the small screen whose phase is inverted for each line will be This cancels out and removes the cross color.

Embodiment Hereinafter, a two-screen television according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a two-screen television in one embodiment of the present invention.

In Fig. 1, 1 is an input terminal for the main screen video signal;
is an A/D converter, 3 is a scanning line interpolation circuit, 4 is an input terminal for a video signal for a small screen, 5 is an A/D converter, 6 is a vertical interpolation filter circuit, 7 is a horizontal interpolation filter circuit, 8 is a frame 9 is a frame memory, 10 is a main screen small screen synthesis circuit, 11 is a main screen small screen synthesis circuit, 12 is a double speed conversion circuit, 13 is a double speed conversion circuit, 14 is a D/A converter, 15 is a main screen child The screen composite video signal output terminal 18 is a motion detection circuit which operates in the same way as the conventional example shown in FIG. 5 and is given the same number. 30 is a YC separation circuit connected to the output end of the A/D converter 2, which separates the luminance signal and the color difference signal. 31 is a selection circuit that switches between the VC-separated main screen video signal and the input sub-screen video signal.

The operation of the two-screen television configured as described above will be described below.

The yc separation circuit 30 outputs a signal processed between lines in the case of a moving image based on the output of the motion detection circuit 18, and outputs a signal processed between frames in the case of a still image.The 0 selection circuit 31 outputs a signal processed between frames in the case of a still image. When the sub-screens are the same or when only one input is required, such as channel search, use the motion-adaptive YC separation circuit 3.
0 output is selected, and if two different inputs are required, the video signal input to the small screen video signal input terminal 4 is selected.

As described above, according to this embodiment, the YC separation circuit 30 is adapted to the main screen video signal path, and the selection circuit switches between the output of the VC separation circuit 30 and the video signal input to the child screen video signal input terminal. By providing 31, the signal of the sub-screen video can be switched.

Next, one embodiment of the configuration of the interpolation filter circuit 6 will be described. FIG. 2 is a block diagram showing an example of the configuration of an interpolation filter circuit.

In FIG. 2, 19 is an input terminal of the interpolation filter circuit 6, and 20 is an output terminal of the interpolation filter circuit 6. The vertical interpolation filter circuit 6 includes a time axis multiplexing circuit 34, a line memory 16, a time axis separation circuit 35, and an adder 17. 7 is a horizontal interpolation filter circuit.

The operation of the two-screen television configured as described above will be described below.

Considering the case where the size of the sub-screen is reduced to 1/n in the vertical direction, the time axis weighting circuit 34 multiplexes the video signal on the time axis and reduces the data rate to 1/n, thereby creating a line memo. The time axis separation circuit 35, which reduces the input to January 6 to 1/n bits, returns the multiplexed video signal output of the line memory to its original speed, and the adder 17 returns the input video signal to the input video signal. The output signal of the adder 17, which takes the average of the IH-delayed video signals and performs vertical interpolation, is sent to a horizontal interpolation filter circuit 7, which performs horizontal interpolation to complete the interpolation.

As described above, according to this embodiment, the interpolation filter circuit for the child screen video signal is configured in the vertical and horizontal directions, and the time axis multiplexing circuit 34 is provided on the input side of the line memory 16, and the time axis multiplexing circuit 34 is provided on the output side of the line memory 16. By providing the separation circuit 35, the number of input bits of the line memory 16 can be reduced to 1/n.

Next, an embodiment of the configuration of the interpolation filter circuit of the sub-screen luminance signal path will be described. FIG. 3 is a block diagram showing an example of the configuration of an interpolation filter circuit in a child screen luminance signal path.

In FIG. 3, 191 is an input terminal for a sub-screen luminance signal, 6 is a vertical interpolation filter circuit, 36 is a selection circuit for switching between the input luminance signal and the output of the vertical interpolation filter circuit 6, and 7 is a horizontal interpolation filter. A circuit 201 is an output terminal for the interpolated luminance signal.

The operation of the two-screen television configured as described above will be described below.

A television receiver that performs progressive scan conversion has a field of 525 lines/l, and a sub-screen reduced to 2 in the vertical direction is 52 lines/l field.
5/2 lines/1 field. The signal input to the sub screen video signal input terminal 191 is 525/2 line/
Since it is one field, no vertical interpolation is necessary when reducing to two. Therefore, when selecting the luminance signal input to the input terminal 191 and reducing it to a value other than 2, the selection circuit 36 selects the output of the vertical interpolation filter circuit 6. The output signal of the selection circuit 36 is subjected to horizontal interpolation in the horizontal interpolation filter circuit 7.

As described above, according to this embodiment, in the path of the child screen luminance signal, there is a selection of switching between a path that does not pass through the vertical interpolation filter circuit 6 and a signal input from the output of the vertical interpolation filter circuit 6 and the input terminal 191. By providing the circuit 36, when the vertical reduction rate of the child screen is 2, no vertical interpolation is performed.

Next, an embodiment of the configuration of the interpolation filter circuit of the child screen color difference signal path will be described. FIG. 4 is a block diagram showing an example of the configuration of an interpolation filter circuit in the child screen color difference signal path.

In FIG. 4, 192 is an input terminal of a color difference signal for a sub-screen, 6 is a vertical interpolation filter circuit, 37 is a selection circuit for switching between the input color difference signal and the vertically interpolated color difference signal, and 7 is a horizontal interpolation filter circuit. , 202 are output terminals for interpolated color difference signals.

The operation of the two-screen television configured as described above will be described below.

Similarly to the embodiment shown in FIG. 3, the selection circuit 37 outputs the color difference signal input to the input terminal 192 when the vertical reduction rate of the child screen is %, and when,
Outputs vertically interpolated color difference signals. However, when the input color difference signal is a video signal that is not subjected to YC separation, the color difference signal that has passed through the vertical interpolation filter circuit 6 is selected even when the size of the child screen is reduced by A in the vertical direction.

As described above, according to the present embodiment, in the path of the sub-screen color difference signal, there is a path that does not pass through the vertical interpolation filter circuit 6, and a selection circuit that switches between the output of the vertical interpolation filter circuit 6 and the input signal from the input terminal 192. 37 is provided, and when a video signal is input, the color difference signal that has passed through the vertical interpolation filter circuit 6 is always selected regardless of the reduction rate of the child screen.

Effects of the Invention As described above, according to the present invention, the (+) main screen video signal input terminal and the first A/D
a converter, a motion detection circuit and a VC separation circuit connected to the output terminal of the first A/D converter, a video signal input terminal for a small screen, a second A/D converter, and a VC separation circuit. By providing a first selection circuit that switches between the output signal of the A/D converter and the output signal of the second A/D converter, three-dimensional YC separation is possible when only one input is required, such as when the parent screen and child screen are the same. By using the video signal obtained as the video signal for the sub-screen,
It can be made into a high-quality sub-screen.

(2) A time axis multiplexing circuit connected to the output terminal of the first selection circuit, a line memory, a time axis separation circuit, and an adder that averages the output signal of the selection circuit and the output signal of the time axis separation circuit. By providing a horizontal interpolation filter circuit, the storage capacity of the line memory can be reduced.

(3) Providing a brightness signal input terminal for a child screen, a vertical interpolation filter circuit connected to the input terminal, a second selection circuit for switching between the input signal and the output signal of the vertical interpolation filter circuit, and a horizontal interpolation filter circuit. This makes it possible to improve the vertical resolution when reducing the child screen to A in the vertical direction.

(4) By providing a color difference signal input terminal for a child screen, a vertical interpolation filter circuit connected to the input terminal, a third selection circuit for switching between the input signal and the output of the vertical interpolation filter circuit, and a horizontal interpolation filter circuit. , when inputting video, it is possible to remove the cross color of the sub-screen image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a two-screen TV according to an embodiment of the present invention, FIG. 2 is a block diagram showing an embodiment of the configuration of an interpolation filter circuit, and FIG. 3 is an interpolation filter circuit in a child screen brightness signal path. 4 is a block diagram showing an example of the configuration of the interpolation filter circuit in the child screen color difference signal path. FIG. 5 is a block diagram of a conventional two-screen television. FIG. 6 is a block diagram 1 showing the structure of an interpolation filter circuit in a conventional luminance signal path for a small screen, and FIG. 7 is a block diagram showing the structure of an interpolation filter circuit in a conventional color difference signal path for a small screen. 1...Video signal input terminal for main screen, 2,5...
...A/D converter, 4...Video signal input terminal for small screen, 6...Vertical interpolation filter circuit, 7.
...Horizontal interpolation filter circuit, 16...Line memory, 17.Old...Adder, 1B...Motion detection circuit, 19...Interpolation filter circuit input Terminal, 20... Interpolation filter circuit output terminal, 3o
...YC separation circuit, 31.36.37...
...Selection circuit, 34...Time axis multiplex circuit, 35
...Time axis separation circuit, 191...Brightness signal input terminal for sub-screen, 192...Color difference signal input terminal for sub-screen, 201...Sub-screen 202... Interpolated color difference signal output terminal for sub screen.

Claims (4)

[Claims] (1) A video signal input terminal for the main screen, a first analog-to-digital converter connected to the video signal input terminal for the main screen, and a motion detection device connected to the output end of the first analog-to-digital converter. circuit, a YC separation circuit, a sub-screen video signal input terminal, a second analog-to-digital converter connected to the sub-screen video signal input terminal, and the YC
A two-screen television comprising a first selection circuit with two inputs and one output that switches between the output signal of the separation circuit and the output signal of the second analog-to-digital converter. (2) A vertical interpolation filter circuit connected to the output end of the first selection circuit, and a horizontal interpolation filter circuit connected to the output end of the vertical interpolation filter circuit, the vertical interpolation filter circuit being a video signal converter. an input terminal, a time multiplex circuit connected to the input terminal, a line memory connected to the output end of the time multiplex circuit, a time separation circuit connected to the output end of the line memory, and the input terminal and the time separation circuit. A two-screen television comprising an adder connected to the output end of the television. (3) an input terminal for a sub-screen luminance signal, a vertical interpolation filter circuit connected to the luminance signal input terminal, a second selection circuit that switches between the input luminance signal and the output signal of the vertical interpolation filter circuit; and a horizontal interpolation filter circuit connected to the output end of the second selection circuit. (4) an input terminal for a child screen color difference signal; a vertical interpolation filter circuit connected to the color difference signal input terminal; a third selection circuit for switching between the input color difference signal and the output signal of the vertical interpolation filter circuit; and a horizontal interpolation filter circuit connected to the output end of the selection circuit of No. 3.