JPH0638649B2 - High-definition television receiver with dual-screen display function - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a television receiver capable of simultaneously displaying a moving image and a still image on one screen.

[Background of the Invention]

In recent years, in order to effectively utilize a CRT screen in a television receiver, other TV programs are reduced and displayed on a part of the original TV screen. A so-called small screen insertion (P in P) television has been announced (Japanese Patent Laid-Open No. 54-54).
98116). This P in P
The concept of (in picture) will be briefly described below with reference to FIGS. 6 to 9.

FIG. 6 is a conceptual diagram of the P in P screen. 101 is a television receiver, 102 is a cathode ray tube, 103 is a parent screen part, 104 is a small screen part into which another program screen is reduced and inserted, and The screens and small screens are of a format that allows independent channel selection.

FIG. 7 shows an example of a small screen insertion method. I is the small screen before reduction, and II is the parent screen in which the small screen is inserted. If the screen reduction rate is (scanning cycle after reduction) / (scanning cycle of original signal), and the screen reduction rate of the small screen is set to 1/3 in the vertical and horizontal directions, one scanning line from three screens of the small screen I. It is extracted, and the horizontal period is time-compressed to 1/3 to synchronize with the main screen and then inserted into the main screen. Scan line-shows a part of the scan line before and after reduction.

FIG. 8 shows the state of small screen insertion on the time axis. I is the video signal of the small screen before reduction, and II is the video signal of the parent screen in which the small screen is inserted. From the video signal I of the small screen, as shown in FIG. 7, one scanning line is extracted for every three lines and written in the analog or digital field memory III, and the small screen insertion position of the video signal II of the main screen ( It is possible to obtain a two-screen television signal by reading using the clock of three parts in the thick line part). Field memory at this time
III requires A and B2 fields. That is, while reading the memory A, the next field is written in the memory B, and when reading the memory B, the memory A
Write the next field in. FIG. 9 shows the configuration of a conventional P in P television. In the figure, 401 is an antenna, 402 is a small screen insertion circuit, 403 is a video processing circuit, 404 is a cathode ray tube, 405 is a main screen tuner,
406 is an IF / video detection circuit, 407 is a sync separation circuit,
408 is a small screen tuner, 409 is an IF / video detection circuit, 410 is a sync separation circuit, 411 and 412 are field memories A and B, 413 is a write clock generation circuit,
Reference numeral 414 is a read clock generation circuit.

The small-screen video signal obtained by the tuner 408 and the IF / video detection circuit 409 is written to, for example, the A field memory 411 by the write clock generation circuit 413 whose timing is adjusted by the sync separation circuit 410. During this period, the video signal one field before written in the B field memory 412 is a read clock generation circuit 414 whose insertion timing is determined according to the sync signal separated by the sync separation circuit 407 from the video signal of the parent screen. Is read out by the clock of and is inserted into the video signal of the main screen by the small screen insertion circuit 402. If writing to the field memory for the small screen is stopped here, a still image can be obtained.

In the child screen of the conventional P in P television described above, the number of scanning lines is reduced to, for example, 1/3, and the number of samples in the horizontal period is reduced to, for example, 100. Therefore, the image quality is rough and fine characters can be read. There was a drawback that I could not.
In addition, there is also a problem in that there is practically no need to tune in to watch other channel programs at the same time, in other words, there is little demand for watching, and therefore the significance of existence in practice is doubtful.

[Object of the Invention]

The present invention has been conceived in view of the conventional technical circumstances as described above, and therefore the object of the present invention is to provide a high-quality image regardless of whether it is a parent screen or a child screen. Moreover, even if it is called P in P, it is not possible to see the programs of other channels at the same time, but the screen of the same program can be viewed in P in P as a moving image and a still image. To provide a machine.

[Outline of Invention]

In order to achieve this object, in the present invention, the sizes of the moving image and the still image are made equal, and with respect to the moving image, scanning line interpolation by a line memory is performed. As for still images, one field memory is used, the number of samples in the horizontal period is set to about 300, and scanning line interpolation is performed using all scanning lines to obtain a high-quality image.

Further, for the color difference signal, the fact that the frequency band of the color difference signal is narrower than that of the luminance signal is used, and two color difference signals are multiplexed into one signal processing.

Example of Invention

An embodiment of the present invention will be described below with reference to FIG. First
The figure is a block diagram showing the function of the television receiver according to the present invention, in which 501 is a scanning line conversion circuit,
Reference numeral 502 is a deflection circuit, and the same parts as those in FIG. 9 are denoted by the same reference numerals.

Next, the operation of the embodiment of the present invention will be described. Antenna 401, tuner 405, IF / video detection circuit 406
The video signal processed in (1) is separated by a sync separation circuit 407 to generate a horizontal sync signal having a double repetition frequency. The deflection circuit 502 drives the scanning system by the horizontal synchronizing signal and the vertical synchronizing signal having the doubled frequency. The video signal converted by the scanning line conversion circuit 501 is displayed on the cathode ray tube 404 after being subjected to various controls (for example, contrast, hue, saturation, image quality, etc.) by the video processing circuit 403.

Next, a detailed block diagram of the scanning line conversion circuit 501 is shown in FIG. 2A, and its operation will be described.

In FIG. 2A, 601 is a luminance signal input terminal, 602 is a field memory, 603 is a switch (S ₁ ), 604, 6
05 is a line buffer memory, 606 is a switch (S ₂ ),
607 is a switch (S ₃ ), 608, 609 and 610 are line memories, 611 is a switch (S ₄ ), 612 is an averager, 6
13 is a signal multiplexer, 614 is a luminance signal output terminal, 615
Is a sync signal input terminal, 616 is a control circuit, and 617 is a screen switching switch (S ₅ ).

First, the luminance signal will be described. First, the input terminal 60
When the luminance signal is input to 1, the field memory 602 stores the image for one field. Since a new screen is written for each stored field, the current image and the image stored in the field memory are always shifted by one field. When the screen switching switch 617 is switched to the 2 screen side, the field memory 602 is controlled by the control signal output from the control circuit 616, and the writing is stopped and only the reading is performed. In the same state, the still image information is output to the output of the field memory 602.

This image information is written by selecting one of the line buffer memories 604 and 605 by the switch (S ₁ ) 603. One line buffer memory (eg 60
When 4) is writing, the other line buffer memory (for example, 605) is in the reading state, and the switch (S ₂ ) 6
The image information is output by connecting with 06. Since this line buffer reads the image information at a clock which is four times as fast as when writing, the image is compressed in half in the horizontal direction when it is displayed on a television whose horizontal frequency is twice the normal frequency.

Next, the operation of the line memory, which is the other signal flow, will be described.

When a luminance signal is input from the input terminal 601, the switch (S
₃ ) 607 switches at every horizontal cycle and connects the signal to any one of the line memories in the next stage. In the line memory, writing (W) is performed at a normal speed as shown in FIG. Read (R) is twice as fast as writing. The three line memories alternately repeat this at the timings shown in FIG. 3 to obtain a continuous video signal at twice the speed. The switch (S ₄ ) 611 switches the video signal output from the line memory as shown in FIGS. 3A and 3B and outputs two continuous video signals.

The A signal train and the B signal train are always delayed by 1/2 horizontal cycle from the B signal train.

If the A signal sequence and the B signal sequence are averaged by the averaging unit 612, a high-quality image in which a scanning line obtained by newly averaging the upper and lower scanning lines is interpolated between the upper and lower scanning lines as shown in FIG. 3C. Signal is obtained. Further, if only one of the A signal train and the B signal train is taken out by the averaging device 612, a high-quality signal in which the scanning line is repeated twice can be obtained.

Here, the screen switching switch (S ₅ ) 617 in FIG.
When switching to the screen side, the three line memories 608, 609, 61 are controlled by the control signal output from the control circuit 616.
When 0, the amount of video information is halved at the time of writing, and reading is performed at twice the speed at the time of writing.

This will be described with reference to FIG. The rectangle in the same figure shows one line memory, and one division in the rectangle shows a cell in which one sample is inserted. FIG. 3A shows the operation of a normal line memory, and video information is written from 1 in order. (b)
Shows the state of the line memory in the case of two screens, and the video information is sent in order from 1, but the information amount is halved by writing every other video information at the time of writing.

The reading is performed at a speed twice as fast as usual from the head, so that the image information compressed in the horizontal direction by 1/2 is obtained at the output. Further, by operating the signal multiplexer 613 to project a moving image on the left side and a still image on the right side in the center of the screen as shown in FIG. 5, a still image of a desired image as shown in FIG. You can see it at the same time. If the screen switch (S ₅ ) 617 is switched to the normal screen, the screen becomes one screen and a normal moving image can be viewed.

Next, the color difference signal will be described.

FIG. 2B is a block diagram showing the processing of the color difference signals of the scanning line conversion circuit 501 in FIG. 1, 620 and 621 are color difference signal input terminals, 622 is a color difference signal multiplexer, 623 is a color difference signal separator, and 624. , 625 are color difference signal output terminals. Also,
The same parts as those in FIG. 2A are designated by the same reference numerals, and the operation thereof is the same as that of the case of the luminance signal, and thus the description thereof is omitted.

When the color difference signals (RY, BY) are input to the color difference signal input terminals 620 and 621 as shown in FIGS. 2C and 2C, respectively, the color difference signal multiplexer 622 outputs two color difference signals as shown in FIG. 2C. Dot-sequential multiplexing.

Here, the color difference signal has half the amount of information as compared with the luminance signal, but since the frequency band of the color difference signal is narrower than that of the luminance signal, there is no visual problem.

The thus-multiplexed color difference signals are processed in the same manner as the luminance signals and input to the color difference signal separator 623. The color difference signal separator 623 performs an operation reverse to that of the color difference signal multiplexer 622. That is, the color-difference signals multiplexed in a dot-sequential manner are alternately taken out to the outputs of the two systems, so that the color-difference signal output terminals 624, 62
In 5, the separated color difference signals (RY, BY) are obtained.

Also, when displaying a still image as a black and white screen, the second
Field memory 602, switch (S ₁ ) 603 in FIG.
This can be achieved simply by removing the line barriers 604 and 605 and the switch (S ₂ ) 606.

〔The invention's effect〕

According to the present invention, by providing the line memory and the simple field memory, the number of scanning lines is 2 for a normal moving image.
You can get a double high-quality image, and a moving image is a high-quality image with twice the number of scanning lines for two screens. Can be seen. Further, since the field memory has a small capacity, there is an effect that the two-screen television receiver can be realized more economically.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2A is a block diagram showing a specific example of a scanning line conversion circuit for luminance signals, and FIG. 2B is a specific example of a scanning line conversion circuit for color difference signals. FIG. 2C is a schematic diagram illustrating a method of multiplexing color difference signals, FIG. 3 is a timing diagram illustrating the operation of the line memory, and FIG. 4 is a schematic diagram illustrating the operation of the line memory when two screens are displayed. FIG. 5 is a conceptual diagram of a screen of a dual-screen television according to the present invention, FIG. 6 is a conceptual diagram of a P in P (picture in picture) screen, and FIGS. 7 and 8 show a small screen insertion method, respectively. FIG. 9 is an explanatory diagram for explaining, and is a block diagram showing a conventional small screen insertion television. Reference numeral 401 ... Antenna, 403 ... Image processing circuit, 404
…… CRT, 405 …… Chuna, 406 …… IF
・ Video detection circuit, 407 ... Sync separation circuit, 501 ...
Scanning line conversion circuit, 502 ... Deflection circuit, 601 ... Luminance signal input terminal, 602 ... Field memory, 603 ...
… Switch (S ₁ ), 604, 605 …… Reinbarhua, 606
...... Switch (S ₂ ), 607 …… Switch (S ₃ ), 608, 60
9,610 …… Line memory, 611 …… Switch (S ₄ ), 6
12 ... Averager, 613 ... Signal multiplexer, 614 ... Luminance signal output terminal, 615 ... Sync signal input terminal, 616
...... Control circuit, 617 ...... Screen switching switch (S ₅ ), 62
0,621 ... color difference signal input terminal, 622 ... color difference signal multiplexer, 623 ... color difference signal separator, 624, 625 ... color difference signal output terminal

Claims (2)

[Claims] 1. A line memory comprising a plurality of line memories capable of storing a video signal for one line in a horizontal direction, and controlling writing and reading of an input video signal to and from the line memory to generate a line interpolation signal The television signal converting means (hereinafter, referred to as TV signal converting means) for converting the television signal by the 2: 1 interlace scanning method as the video signal to a television signal by the 1: 1 non-interlace scanning method and outputting the television signal. And a plurality of line buffer memories, and a field memory capable of storing a video signal of one field, and a plurality of line buffer memories. Controlling writing and reading of the same video signal repeatedly read from the memory to these line buffer memories Therefore, when it is displayed on the screen, it has a still image signal creating means for creating and outputting a still image signal displayed on a dimensionally reduced screen, and a screen switching means. When the screen side is switched to the two-screen side, the TV signal output from the TV signal converting means is converted into a TV signal displayed on a dimensionally reduced screen to generate the still image signal. A high-definition television receiver with a dual-screen display function, characterized in that it is displayed on the same screen as two screens, a moving image and a still image, together with the still image signal output from the means. 2. A television receiver according to claim 1, wherein two color difference signals obtained by YC separating an inputted television signal are:
A television receiver characterized in that these signals are dot-sequentially multiplexed and then processed in the TV signal converting means and the still image signal creating means.