JP2603689Y2 - 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 television receiver which projects a still image on a part of a main screen as a sub-screen or simultaneously projects a plurality of different channels as a still image on one screen. .

[0002]

2. Description of the Related Art There are at least two methods for displaying a second television screen (hereinafter, referred to as a child screen) as a still image in a first television screen (hereinafter, referred to as a parent screen). Each structure is shown in FIGS.

The method shown in FIG. 5 realizes a still image by storing only the data of the first field (or the second field) of the child screen in the field memory 6 and repeatedly reading the data for each field of the parent screen. Things.

In the method shown in FIG. 6, two field data of a first field and a second field of a child screen are stored in first and second field memories 6 and 7, respectively, and the data is repeatedly read for each parent frame. This realizes a still image.

[0005]

The still image obtained by the configuration shown in FIG. 5 has a vertical resolution of about half that of the still image obtained in FIG. 6, and for example, diagonal lines are jagged.

A still image obtained by the configuration shown in FIG.
Although the vertical resolution is about twice as large as that of the above, a still image with blur occurs on a moving image (when there is no correlation between the data of the first field and the second field or the third field).

Therefore, an object of the present invention is to reduce the vertical resolution when there is a correlation between frames in a non-moving image, and to achieve a still image without blur even when there is no correlation between frames in a moving image. An object of the present invention is to provide a television receiver for displaying an image.

[0008]

SUMMARY OF THE INVENTION Therefore, in order to solve the above-mentioned problems, a first invention of the present invention relates to a television receiver for projecting a second television screen on a part of a first television screen. A first field memory that stores data of a second field of the second television screen, a second field memory that stores data of a first field of the second television screen, and a third field memory that stores data of a third field of the second television screen. Data and second
A comparator circuit for comparing the field memory data, before
The difference between the data compared by the comparing circuit is equal to or higher than a certain level.
At the time, the data in the first field memory is rewritten to the data in the second field memory, and the comparison circuit compares the data .
If the data difference is less than a certain level, the first field
And a memory control circuit for causing the read memory to hold the data of the second field and alternately reading and outputting the data of the first field memory and the data of the second field memory for each field of the first television screen. It is a thing.

A second aspect of the present invention is directed to a television receiver for simultaneously projecting a plurality of television screens in a first television screen, comprising: a first field memory for storing data of a second field of the plurality of television screens; A second field memory for storing data of a first field of a plurality of television screens; a synchronization signal generator for generating synchronization signals corresponding to horizontal and vertical synchronization signals of the first television screen; A switching circuit for switching a video signal of one television screen, a comparison circuit for comparing data of a third field of each of the plurality of television screens with data of a second field memory, and a comparison circuit for comparing the data compared by the comparison circuit . Level difference
If the value is equal to or greater than the threshold value, the data in the first field memory is rewritten to the data in the second field memory,
If the difference between the compared data is less than a certain level, the first
Field data holds the data of the second field.
Allowed, and a memory control circuit that reads and outputs the data of the first field memory data and the second field memory alternately in units of fields, the
When the switching circuit is switching to the synchronization signal,
Memory controller that reads and outputs based on the
And a control circuit .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. Since the luminance signal and the color difference signal are basically the same, only the luminance signal will be described. The same applies to a signal in which a luminance signal and a color difference signal are time-division multiplexed.

FIG. 1 is a block diagram of a television receiver according to the present invention, and FIG. 2 is a diagram schematically illustrating an operation on a time axis.

In FIG. 1, during the first field period of the child screen, the luminance signal data of the first field, which has been A / D-converted by the A / D converter 4 based on the clock from the memory control circuit 13, is supplied to the memory control circuit 13
Is written to the first field memory 6 via the first switching circuit 5 switched to the input side 5a of the A / D converter 4 based on the control command from the A / D converter 4.

Next, during the second field period of the child screen, the data read from the first field memory 6 is written into the second field memory 7 based on the control command from the memory control circuit 13, and is written into the first field memory 6. Is the second of the sub-screen which is A / D converted and passed through the first switching circuit 5
The field period data is stored.

Next, the memory control circuit 13 sets the first switching circuit 5 to the output side 5b of the second field memory 7 during the third field period of the child screen,
The first field data stored in the second field memory 7 and the A / D converted third field data are compared in pixel units of the same address (pixel data at the same screen position). When the absolute value of the difference is equal to or higher than a certain level, the data in the second field memory 7 is written to the first field memory 6;
The data in the field memory 6 holds the data in the second field.

Next, the memory control circuit 13
The data of the first field memory 6 and the data of the second field memory 7 which have been written during the field period are alternately switched by the second switching circuit 8 for each field of the parent screen, and the D / A converter 9 performs D / A conversion. The analog image is converted and a still image of the analog small screen is output to the main screen small screen switching circuit 11. The main screen sub-screen switching circuit 11 converts the main screen image from the main screen video chroma jungle processing circuit 10 and the small screen still image from the D / A converter 9 into horizontal and Switching is performed in accordance with a control signal generated by the memory control circuit 13 based on the vertical synchronization signals HDR and VDR, and a still image of a child screen is displayed on the main screen. FIG. 5 is a block diagram showing the configuration of the comparison circuit 12.

The above embodiment is an example in which a still image of a child screen is displayed on a certain parent screen. As shown in FIG. 6, a synchronization signal corresponding to the horizontal and vertical synchronization signals of the parent screen is generated. A synchronizing signal generator 19 is provided, and the horizontal and vertical synchronizing signals are switched by a third switching circuit 18 and input to the main screen video chroma jungle processing circuit 10 instead of the main screen video signal. The present invention is also applied to a so-called multi-channel television receiver which simultaneously displays sub-screens of a plurality of different channels by writing and reading sub-screen data of a plurality of different channels in the field memories 6 and 7, respectively. What you can do is obvious.

[0017]

As described above, the present invention includes two field memories and a comparison circuit, stores the data of the first field in the second field memory, and stores the data of the second field in the first field memory. The data is stored in a comparison circuit, and data in the first field and data in the third field are compared to detect a correlation between frames. When there is no correlation (a moving image), the data in the second field memory is stored in the first field memory. Is written by the conventional method shown in FIG. 5, and when there is a correlation (an image without motion), the first image is created.
By generating a still image by the conventional method shown in FIG. 6 without rewriting the contents of the field memory, it is possible to provide a still image without blurring the information amount as much as possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a television receiver of the present invention.

FIG. 2 is a schematic diagram showing an operation according to FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a comparison circuit according to FIG. 1;

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a block diagram showing one embodiment of a conventional television receiver.

FIG. 6 is a block diagram showing another embodiment of a conventional television receiver.

[Explanation of symbols]

 1, 2 input signal switching circuit 3 video chroma jungle processing circuit for small screen 4 A / D converter 5 1st switching circuit 6 1st field memory 7 2nd field memory 8 2nd switching circuit 9 D / A converter 10 For main screen Video chroma jungle processing circuit 11 Main screen sub screen switching circuit 12 Comparison circuit 13 Memory control circuit 14 Inversion circuit 15 Addition circuit 16 Absolute value circuit 17 Comparator 18 Third switching circuit 19 Synchronization signal generation circuit

Continuing from the front page Examiner Masahiro Ohno (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 5/45 H04N 5/265

Claims (2)

(57) [Scope of request for utility model registration] 1. A television receiver for displaying a second television screen on a part of a first television screen, comprising: a first field memory for storing data of a second field of the second television screen; a second field memory for storing data of the first field of the second television screen, and a third field of the data of the second television screen a comparator circuit for comparing the data of the second field memory, the comparator circuit comparing The level of the data
In the above case, the data in the first field memory is rewritten to the data in the second field memory, and the comparison circuit compares the data.
If the difference between the data is less than a certain level, the first fee
Holding the data of the second field in the field memory,
And a memory control circuit for alternately reading and outputting the data of the first field memory and the data of the second field memory for each field of the first television screen. 2. The method according to claim 1 , wherein a plurality of television screens are included in the first television screen.
In a television receiver that simultaneously displays the second field of a plurality of television screens
A first field memory for storing data of a first field of the plurality of television screens;
A second field memory and a memory corresponding to the horizontal and vertical synchronizing signals of the first television screen;
Synchronizing signal generator for generating a synchronizing signal and switching between the synchronizing signal and the video signal of the first television screen
Switching circuit, and the third field data of each of the plurality of television screens.
A comparison circuit for comparing the data of the two-field memory, and a difference between the data compared by the comparison circuit at a certain level or less.
In the above case, the data in the first field memory is
Rewriting the data of Rudomemori, said comparator circuit compares
If the difference between the data is less than a certain level, the first fee
Holding the data of the second field in the field memory,
And the data of the first field memory and the second field
Read data alternately from memory and field memory
A memory control circuit that outputs
When the circuit is switching to the synchronization signal, the synchronization signal
Memory control circuit to read and output based on
A television receiver comprising a road and a road.