JP3290677B2 - Multi-screen television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-screen television having a picture-in-picture (PIP) system capable of displaying a plurality of images on one monitor screen by simultaneously performing a plurality of screen processes. The present invention relates to a television receiver, and more particularly to a multi-screen television receiver for displaying a screen of a current system on a screen of a high-vision system.

[0002]

2. Description of the Related Art At present, television broadcasting in the NTSC system is being carried out in Japan, and high-definition television broadcasting (high definition) with a large screen and high definition is about to be started. In this high-definition television, the aspect ratio of the screen is different from that of the current NTSC system, and a wide-screen (aspect ratio 16: 9) receiver is used. It is necessary to display an image having an aspect ratio of 4: 3 in the current system even in such a wide-screen receiver.

When an image having an aspect ratio of 4: 3 is directly displayed on a screen of a receiver having an aspect ratio of 16: 9, the image extends horizontally.
To display at a circularity of 1, the horizontal direction
Should be compressed. However, in this case , margins are left and right on the screen. Eliminate this blank part and display at the perfect circle ratio 1.
If it is not compressed in the horizontal direction and expanded in the vertical direction, it can be displayed on the entire screen with an aspect ratio of 16: 9 .
The upper and lower parts of the screen are cut. Illustrates this state is shown in FIG 4
You.

FIG. 4A shows an aspect ratio of 16:
This is a method of displaying all the 4: 3 images on the screen 9, and blank spaces (hatched portions in the figure) are generated on the left and right. (B) shows a case where the 4: 3 image is enlarged and displayed in order to eliminate the margin, and the upper and lower portions (dotted line portions in the figure) of the image are cut.

When a sub-screen (aspect ratio 4: 3) according to the PIP method is displayed on such a screen, the vertical range of the sub-screen in FIG. 4A is "A", but in FIG. The vertical range of the sub-screen is "B"(B> A). This is because the sub-screen has the same vertical thinning rate,
The aspect ratio of the sub-screen of FIG. 4A is 4: 3, whereas the aspect ratio of the sub-screen of FIG. 4B is not 4: 3. That is, the number of thinned scanning lines per screen is the same in both FIGS. 4A and 4B.
4B, only the vertical direction of the sub-screen is enlarged as compared with FIG. 4A. Therefore, the compression ratios in the horizontal and vertical directions do not match, resulting in an unnatural screen.

[0006]

As described above, all images of the current system are displayed on a wide screen, and PIP is displayed on this screen.
When displaying the sub-screen by the method, the aspect ratio of the sub-screen does not become 4: 3, so that the compression ratios in the horizontal and vertical directions do not match, resulting in an unnatural screen.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a natural sub-screen even when all images of the current system are displayed on a wide screen and a sub-screen of the PIP system is displayed on this screen. With the goal.

[0008]

SUMMARY OF THE INVENTION A multi-screen television receiver according to the present invention comprises a first image having an aspect ratio of n2: m (n1> n2) on a monitor screen having an aspect ratio of n1: m.
An image based on the first video signal can be displayed in the first display mode, or in the vertical direction substantially n1
/ N2 display means for displaying in the second display mode enlarged by a factor of 2 and a means for compressing an image based on the second video signal in the horizontal direction and thinning out the image in the vertical direction, and switching the thinning rate in the vertical direction. an image compression means which enables the image compressed by the image compression unit in an image by the first video signal and means for combining the sub screen, the image compressing means, display mode selected In response, the thinning-out argument is switched, and the number of scanning lines of the sub-screen after the thinning-out is changed to the first display mode.
Mode is almost n1 / n2 times that of the second display mode.
In the first display mode and the second display mode.
The vertical height of the sub-screen is approximately similar .

[0009]

According to the method of displaying an image of the current system on a wide screen, the selection means is switched, and scanning lines of the video signal are thinned based on the output of the selection means so that the vertical range of the sub-screen is constant. become. This always provides a natural sub-screen.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The video signal for the sub-screen is input to A through input terminal 1.
/ D (analog to digital converter) 10
It is converted to a digital signal and supplied to the memory 11.
The memory 11 is also supplied with a thinning signal, and thins out the video signal based on the thinning signal and outputs the thinned video signal to a D / A (digital / analog converter) 12. The D / A 12 converts the input signal into an analog signal and outputs it from the output terminal 4. From this output terminal 4, a video signal for the sub-screen is
Output to the first video signal (not shown) for the main screen.
And supplied to display means such as a picture tube.

The configuration of the above-described thinning signal generation circuit will be described. The vertical synchronizing signal (VD) is input to F
F (flip-flop) 13 to 16 clear terminals (C
L). The horizontal synchronizing signal (HD) is supplied to the clock terminals (CK) of the FFs 13 to 16 via the input terminal 2. The output of FF13 is supplied to FF14, the output of FF14 is supplied to FF15, and FF1
5 is supplied to the EX-OR 17. Also FF
13 is also supplied to the EX-OR 17. Further, the inverted output of FF15 is supplied to FF13. The output of the EX-OR 17 is supplied to the selector 18.

On the other hand, the inverted output of the FF 16 is supplied to the input terminal of the FF 16, and the output of the FF 16 is supplied to the selector 18. Further, a control signal is supplied to the selector 18, and one of the two input signals is selected and output. This output signal is the thinning signal described above.

Next, the operation of the circuit of FIG. 1 will be described with reference to FIG. FIG. 2 is a timing chart in the circuit of FIG. In this figure, when the VD signal a rises, FF
13 to 16 output "L" from the output terminal Q of each FF while the data so far is cleared. As a result, “H” is output from the inverted output terminal of the FF 15 and the FF 15
13 input terminal D.

After the VD signal a rises, the HD signal b
Rises first, the output c of the FF 13 changes to "H". Then, at the rising edge of the second clock, FF
The output d of 14 changes to "H", and the output e of the FF 15 changes to "H" at the rising edge of the third clock. At this time, the inverted output of the FF 15 becomes “L”. Therefore, the output c of the FF 13 becomes “L” at the next clock. Thus, the FFs 13 to 15 form a shift register. The output f of the EX-OR 17 is "L" when both the signal c and the signal e are "H" or "L", and is "H" otherwise. Accordingly, the ratio of the signal f is "H" being 2 and the ratio of "L" being 1.

On the other hand, the FF 16 forms a binary counter, and its output is like a signal g. That is, FF1
6 is a signal g in which the ratio of "H" and "L" is 1 each.
Is output.

By the way when displaying the image of the current scheme widescreen and how to display all images as shown in FIG. 3 (a) (hereinafter described as the first method), expanding as shown in FIG. 3 (b)
There is a method of displaying the entire screen (hereinafter referred to as a second method). The control signal supplied to the selector 18 is a signal for switching the output signal of the selector 18 in accordance with the first and second methods. As a result, the signal f is selected when displaying by the first method , and the signal f is selected by the second method .
For display, the signal g is selected. When the thinning signal output from the selector 18 is "H", the video signal is written into the memory 11, and when it is "L", the video signal is thinned without being written.

FIG. 3 shows the configuration of the sub-screen when such a thinning signal is used. In this figure, (a) shows a case where the image is displayed by the first method , and (b) shows a case where the image is displayed by the second method . Here, when the numbers S1 and S2 of the scanning lines used for the sub-screen per field by the first and second methods are obtained, the equations (1) and (2) are obtained.

S1 = (525/2) × (2/3) × (1 / n) (1) S2 = (525/2) × (1/2) × (1 / n) (2) (1) In the formula, (2/3) is the thinning rate, and the scanning line
Two of the three are written to memory 11 and one is decimated.
I will In the equation (2), (1/2) is a thinning rate.
Yes, one of two scanning lines is written to memory 11
Means that one is thinned out. Also (1)
In equation (2), (1 / n) represents the size of the sub-screen.
Is any factor that determines, when the n = 2, compared with the case of displaying with S1 = (525/2) × 1/ 3, S2 = (525/2) × 1/4 , and the first method, Display in the second way
In this case, the number of arguments is larger. By changing the thinning rate in this way, the vertical height of the sub-screen can be set to “A” in both the first and second methods. This is because interval between scanning lines is large specific base second method to the first method. Therefore, the horizontal and vertical compression ratios of the sub-screen match, and a natural sub-screen can always be provided.

As described above, when an image of the current system is displayed on a wide screen and a sub-screen is inserted in the screen by the PIP system, there are two types of display methods. By changing the thinning rate of the scanning lines in accordance with this display method, it is possible to always provide a natural sub-screen.

[0020]

As described above, when an image of the current system is displayed on a high-definition wide screen and a sub-screen is inserted in the screen by the PIP method, the thinning rate of scanning lines is changed according to the display method. It is possible to always provide a natural sub-screen.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention.

FIG. 2 is a timing chart for explaining the operation in FIG. 1;

FIG. 3 is an explanatory diagram illustrating a sub-screen display method according to the present invention.

FIG. 4 is an explanatory view for explaining a conventional sub-screen display method.

[Explanation of symbols]

 10 A / D 11 Memory 12 D / A 13-16 FF 17 EX-OR 18 Selector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/45-5/46 H04N 7/01

Claims (2)

(57) [Claims] 1. A first image having an aspect ratio of n2: m (n1> n2) on a monitor screen having an aspect ratio of n1: m.
An image based on the first video signal can be displayed in the first display mode, or in the vertical direction substantially n1
Display selection means for displaying in the second display mode enlarged by a factor of / n2, and means for compressing an image based on the second video signal in the horizontal direction and thinning out in the vertical direction, and switching the thinning rate in the vertical direction. an image compression means which enables the image compressed by the image compression unit in an image by the first video signal and means for combining the sub screen, the image compressing means, display mode selected In response, the thinning-out argument is switched, and the number of scanning lines of the
Is approximately n1 / n2 times that of the second display mode.
In the first display mode and the second display mode.
A multi-screen television receiver characterized in that the vertical height of the sub-screen in the screen is approximately similar . 2. The monitor has an aspect ratio of 16: 9.
And the aspect ratio of the image based on the first video signal is
When the ratio is 12: 9, the image compressing means may store the image based on the second video signal in the memory using a vertical synchronization signal and a horizontal synchronization signal of the second video signal. Generating a signal for controlling writing of the second video signal, wherein the second video signal is a first signal that permits writing of two of three scanning lines.
And the second video signal are output from one of two scanning lines.
Signal generating means for generating a second signal permitting writing of a book; selecting the first signal in the first display mode and selecting the second signal in the second display mode Means for outputting a second video signal decimated in accordance with the first or second signal selected by said selecting means from said memory. Screen television receiver.