JPH0350969A - How to display a reduced screen on high-definition television - Google Patents

Abstract

PURPOSE:To improve the vertical resolution and to suppress picture flicker of a slave picture by providing an odd number field memory an even number field memory storing a signal of a scanning line of a picture and a switch or the like. CONSTITUTION:An odd number field memory 5, an even number field memory 6 storing a picture signal and a switch 7 are provided to reduce a picture and to display a reduced picture (slave picture) of the picture to part of the picture. A signal of a scanning line of a picture is stored in the memories 5, 6 and when the signal is read from the memory 5, 1st, 4th, 7th... scanning lines are read and the readout scanning lines of the order are interleaved. When the signal is read from the memory 6, 2nd, 5th, 8th... scanning lines are read and the readout scanning lines during that time are interleaved. The interleaved scanning lines are change over by the switch 7 and the summed scanning line is analog-converted by a sampling frequency in response to the reduce picture at a D/A converter 8, then the vertical resolution is increased to suppress picture flicker or the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is based on PIP (Picture In Pic).
high-definition television (e.g. HD
TV;ExtandadDefinition Ding V)
More specifically, the present invention relates to a reduced screen display method for a high-definition television that uses the PIF function to increase the vertical resolution of the reduced screen to make the image on the reduced screen easier to see.

[Conventional Example] In recent years, consumer needs for high-definition televisions have increased, and various high-definition televisions that improve the quality of terrestrial broadcast images, for example, have been proposed. The EDTV system, one of them, requires only improvements to the NTSC system and has advantages such as requiring less equipment costs for television broadcasting stations.

Furthermore, high-definition televisions based on the HDTV system utilize digital technology, and have been proposed to be equipped with various functions, such as a PIF function. In this PIF function, when a reduced screen (child screen) is superimposed on a screen (main screen), the number of scanning lines is thinned out to reduce the size in the vertical direction, and the signal after this thinning and the signal of the main screen are When switching the scan lines and converting the scan lines drawn therebetween into analog data using a D/A converter, the sampling frequency of the analog conversion is set to a value corresponding to the horizontal reduction of the reduced screen (child screen). Here, if the child screen is, for example, 179 of the main screen, the number of scanning lines is reduced to 1/3 in the vertical direction and 273 to display at double speed.
need to be converted to .

Therefore, as shown in FIG. 4, for example, a high-definition television has an odd/even field memory 1, a 1-line memory 2 for storing data read from the field memory 1, and a 1-line memory 2 for storing data read out from the field memory 1. An adder 3 for adding data read from the memory 2 and data read from the field memory 1, and a multiplier 4 for multiplying the added data by 172 are provided. and.

As shown in FIGS. 5 and 6, when reducing an image, the image to be reduced is doubled in the number of scanning lines and stored in the field memory 1. When reading a bit data string),
Leave one scanning line as it is, average the following two scanning lines, make this averaged scanning line one scanning line, and repeat the process to obtain all the scanning lines of the sub screen. That's what I do.

[Problems to be Solved by the Invention] However, in the above-mentioned reduced screen display method for high-definition television, since the scanning line of the image on the sub-screen includes an average of two scanning lines, /The information of the scanning line stored in the even field memory 1 is different from the averaged scanning line, which may cause deterioration of the resolution in the vertical direction, for example. In other words, if a straight line in the horizontal direction is displayed as a sub-screen display, and the information of the scanning lines corresponding to the straight line is averaged as described above, flickering of the sub-screen, that is, an image flicker on the sub-screen will occur. There was a problem that this occurred.

This invention has been made in view of the above problems, and its purpose is to provide a reduced screen display method for high-definition television that can increase the vertical resolution and suppress image flicker on the sub-screen. There is a particular thing.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a reduced screen display method for a high-definition television that reduces an image and displays the reduced screen of the image on a part of the screen. When reducing the image, the signals of the scanning lines of the image are stored in the odd/even field memory, and the signals of the scanning lines of the image are stored in the odd/even field memory.
One scanning line segment is read out alternately from the memory, and the one scanning line segment to be read out is thinned out in accordance with the reduced screen.

When thinning out one scanning line, the number of scanning lines to be thinned out is changed between the odd field memory and the even field memory, and the signal of the reduced screen is obtained by using these different numbers of scanning lines. shall be.

[Operation] Since the above method is used, when thinning out the scanning lines read from the odd/even field memory according to the reduced screen size,
Two scanning line segments are not averaged into one scanning line segment, but the numbers of scanning lines that are thinned out and read out from the odd field memory and the even field memory are different. In other words, the scan lines after being thinned out by 1 are not averaged and are stored as they are in the odd/even field memory, so the vertical resolution of the screen is high, which may cause image flickering. do not have.

[Example] Embodiments of the present invention will be described below based on the drawings.

In Figure 1, a high-definition television has an image signal (
For example, a field memory for storing 8-bit data) is provided, and this field memory is provided with an odd field memory 5 and an even field memory 6. One scanning line of the image is read out alternately for each scanning line from the odd-7-even field memories 5 and 6.
For example, when obtaining a 1/9 sub-screen, as shown in FIG. The second scanning line segment of the even field memory 6 is read out as is, and then the odd field memory 6 is read out as is.
The fourth scanning line segment of the memory 5 is read out as is.

The thinned out scanning lines read from the odd/even field memories 5 and 6 are switched by the switch 7, and the added scanning lines are converted to the reduced screen ( (horizontal reduction).

In this way, when reading one scanning line from the odd field memory 5, one scanning line of the 1st, 4th, 7th, etc. is read out, and the scanning line read out at rljlI is Further, when reading one scanning line from the even field memory 6, the second, fifth,
One scanning line of the 8th grain, . That is, the number of scanning lines read out from the odd field memory 5 and the even field memory 6 is made different, and information on the scanning lines of the child screen is not partially missing. Note that the scanning lines after the above-described thinning are maintained in an interlaced relationship.

Then, as shown in FIG. 3, since the thinned out scanning lines and the scanning lines of the main screen are switched by the switch unit 9, the main screen and the 179 child screen are overlapped on the screen 10, and the display be done. Furthermore, since the information on each scanning line of the sub-screen is the same as the information stored in the odd-7-even field memories 5 and 6, it is possible to increase the resolution in the vertical direction to be reduced. will not occur.

[Effects of the Invention] As explained above, according to the reduced screen display method for high-definition television of the present invention, the scanning lines read from the odd/even field memory are thinned out in accordance with the reduction of the screen.
When obtaining signals for the reduced screen (child screen) using the thinned out scanning lines, the number of scanning lines read out from the odd field memory and the even field memory is made different.

Since the information on the scanning lines drawn during that time is directly used as a signal for the sub-screen, the vertical resolution of the sub-screen can be increased, and image flicker and the like on the sub-screen can be eliminated.

[Brief explanation of drawings]

FIG. 1 is a schematic partial block diagram of a high-definition television showing an embodiment of the present invention; FIG. 2 is a diagram for explaining a method of thinning out scanning lines in the high-definition television;
FIG. 3 is a double-sided view illustrating the display state of the high-definition television, FIG. 4 is a schematic partial block diagram of a conventional high-definition television, and FIGS. 5 and 6 are diagrams of the conventional high-definition television. FIG. 3 is a screen diagram illustrating a method of thinning out scanning lines. In the figure, 5 is an odd field memory, 6 is an even field memory, 7 is a switch, 8 is a D/A conversion section, 9 is a switch section, and 10 is a screen (of a high-definition television).

Claims (1)

[Claims] (1) In a reduced screen display method for high-definition television that reduces an image and displays a reduced screen of the image on a part of the screen, when reducing the image, the signals of the scanning lines of the image are changed to odd/even numbers. storing in a field memory, alternately reading out one scanning line from the odd/even field memory, thinning out the read one scanning line according to the reduced screen, and thinning out the one scanning line, The reduction of the high-definition television, characterized in that the number of scan lines to be thinned out is different between the odd field memory and the even field memory, and the signal of the reduced screen is obtained by the different numbers of scan lines. Screen display method.