JPH0799617A - Television receiver - Google Patents

Abstract

PURPOSE:To use four field memories, which are used for one slave picture, for three slave pictures and to obtain a dynamic image free from degradation as one of these three slave pictures by efficiently using four field memories in the television receiver with the picture in picture function. CONSTITUTION:The picture signal of the slave picture is stored in a memory 1, and the slave picture is read out from the memory 1 and is displayed in a master picture, and the memory 1 has memories (M1m M2, M3, and M4) of four fields. When the slave picture is set to the one-picture mode by a mode switching circuit 12, a memory 4 is controlled by a write control circuit 6 and a read control circuit 8 to use all of four fields; but when it is set to the three- picture mode, the memory 4 is controlled by a write control circuit 7 and a read control. circuit 9 to use a portion of one field and a portion of two fields for each of two pictures and the other picture respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention displays an image having an aspect ratio of 4: 3 as in the NTSC broadcasting system and an image having an aspect ratio of 16: 9 as in the high-definition broadcasting system on a common screen. The present invention relates to a television receiver that can be used.

[0002]

2. Description of the Related Art A television receiver capable of receiving a high-definition broadcasting system has a screen with an aspect ratio of 16: 9, and can display not only high-definition broadcasting but also a television signal of an NTSC broadcasting system. ing.

By the way, since this television receiver has a screen with an aspect ratio of 16: 9 as described above, all television signals of high-definition broadcasting can be displayed on the screen, but television of NTSC broadcasting. Since the John signal is a 4: 3 screen, when the screen is displayed on a 16: 9 television receiver, the following display method is used.

First, as the first method, a television signal of the NTSC broadcasting system is made to correspond to the horizontal direction of the screen of 16: 9, and the upper and lower sides of the television signal are truncated, and the second method. As a method, there is a method in which a television signal is made to correspond to the vertical direction of a 16: 9 screen and blanking (non-image portion) is formed on the left and right screens.

However, in the above-mentioned first method,
Since a part of the television signal is cut off, the screen becomes difficult to see. Further, in the second method, the left and right screens are non-image parts, 1/4 of the screen width is wasted, and the image itself is a poor image.

Therefore, in order to solve these problems, conventionally,
A method for effectively using the screen without truncating any images having different aspect ratios is disclosed in Japanese Patent Laid-Open No. 3-1400.
No. 72 (H04N7 / 01).

According to this conventional technique, for example, FIG.
As shown in (b), three screens of a 4: 3 image are displayed on a small screen in the right corner, and a large 4: 3 main screen is displayed on the left to make effective use of the screen. It is a thing.

By the way, with such a technique, when a small screen is entirely animated, for example, a method is known in which only the field memory is used. However, when only the field memory is used, The screen image is deteriorated.

Further, it is sufficient to use the frame memory instead of the field memory in order to solve the image deterioration, but there is a problem that the cost becomes high.

Further, when a three-screen moving image is formed, a control unit for controlling the memory of each child screen is required.

On the other hand, a television receiver having a function of displaying a small screen for three screens as in the prior art and a function of displaying only a small screen of one screen shown in FIG. Machine is also proposed. In such a television receiver, a small-screen image for one screen is displayed neatly and three screens are displayed, and a method which does not cost much is used. With this method, four field memories are provided, and in the three-screen display, one screen is used for a total of three memories, and when only one sub-screen is used, four field memories are used.

In the case of such a configuration, even if the conventional state is such that all the three sub-screens are displayed as field still images, only one of the three screens is displayed as a moving image, the memory for one field is used. It was a field video display.

However, in such a field moving image display, the vertical resolution is poor, and it is difficult to see fine characters, and the image quality difference in the moving image display in the three-child screen state is clear as compared with the moving image in the one-child screen state.

Further, among the memory for four fields used in the one-child screen state, the memory for one field is wasted in the three-child screen state.

[0015]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a television receiver with a picture-in-picture function, and uses four field memories for three screens, one of which is a sub-screen. Used for the child screen of
Moreover, it is an object to efficiently use the four field memories so that one of the three screens is a moving image without image deterioration.

[0016]

DISCLOSURE OF THE INVENTION The present invention provides a child which receives an image signal of a main parent screen displayed on a television screen and is displayed on the television screen smaller than the parent screen. Display means for receiving the image signal of the screen and simultaneously displaying the parent screen and the child screen on the television screen, and a one-screen display mode for displaying the child screen for one screen on the parent screen on the display means. And a mode designating means for designating a three-screen display mode in which the child screen is displayed on the display means for three screens with respect to the parent screen, and a field memory for four fields for storing image information of the child screen. In the television receiver, the image information of the sub-screen is used by the mode designating means in the 1-screen mode, the memory for all 4 fields is used, and in the 3-screen mode, the memory is divided into 2 screens. Minute static image displayed using each one field, the remaining one screen is a television receiver characterized by comprising displaying videos using two fields.

Further, according to the present invention, the mode designating means 3 is provided.
The screen mode has a three-screen still image mode designating function, and when the three-screen still image mode is designated, still images are displayed in the three-screen mode using one field for each of the three screens. It is also a television receiver that does.

Further, according to the present invention, a parent screen field discriminating means for discriminating a field of the parent screen, a child screen field discriminating means for discriminating a field of the child screen, and a timing for writing an image signal of the child screen to the memory. And a read control means for controlling the timing of reading the image signal written in the memory, and a parent controller for reading the moving picture child screen image signal in the three-screen mode or the one-screen mode from the memory. A television receiver comprising a screen field discriminating means and a correcting means for discriminating field overtaking by the sub-screen field discriminating means and correcting the read control means.

[0019]

According to the present invention, with the above-mentioned configuration, the sub-picture image memory having a capacity for four fields of the reduced picture is divided into four and used, and in the case of the three sub-picture display, one of the three pictures is displayed. Or any one screen is displayed as a 2-field sequence movie using the memory for 2 fields, and the remaining 2
By using the function to switch between the field still image display state where each screen uses the memory for one field and the state where all three screens are displayed as the field still image, the memory used for one sub-screen display is used without waste. Three
It is possible to improve the image quality of one moving image display screen of the small screen display and improve the image quality difference from the moving image display in the single small screen display state.

[0020]

EXAMPLES Examples of the present invention will be described below. Figure 1
1 shows a block diagram of the present invention. First, 1 is a memory for storing a child screen, and four field memories M1, M2, M
3 and M4. 2 and 3 are changeover switches, and 4 is a write control circuit for the memory 1, which is composed of a 1-screen mode write control circuit 6 and a 3-screen write control circuit 7. Reference numeral 5 denotes a read control circuit of the memory 1, which is a 1-screen mode read control circuit 8 and a 3-screen mode read control circuit 9.
It consists of

Reference numeral 10 is a child screen odd / even field discriminating circuit, 11 is a parent screen odd / even field discriminating circuit, and 12 is a mode switching circuit for switching between 1-screen mode and 3-screen mode.

Next, the operation of the present invention will be described. First, the small screen image memory 1 having a capacity of four fields of reduced images is divided into four and used.
3 and M4. The writing control circuit 4 of the memory 1 is composed of a writing control circuit 6 for a 1-child screen mode and a writing control circuit 7 for a 3-child screen mode, and the switching circuit 2 uses a 1-child screen / 3
Memory 1 by switching the control by the sub-screen mode switching signal
Write control to.

Similarly, the memory read control circuit 5 is composed of a read control circuit 8 for one sub-screen mode and a read control circuit 9 for the three sub-screen mode. Memory control is performed by switching control.

In each circuit of the write control and the read control in the three-screen mode, a 2-bit moving picture position designation signal for deciding any moving picture position among the three screens and all three screens are stopped. A still image / moving image switching signal for displaying an image is input.

Further, the sub-picture odd / even field discriminating circuit 10 discriminates odd and even fields from the sub-picture synchronizing signal and inputs them to the write and read control circuits 4 and 5. The parent screen odd / even field discriminating circuit 11 discriminates odd and even fields from the parent screen synchronizing signal and inputs them to the reading control circuit 5.

In order to access the memory 1, the write control is prioritized, so that the write control circuit 4 reads the read control circuit 5 into which area (M1, M2, M2) of the memory 1 divided into four.
A 2-bit signal indicating whether or not writing is currently performed is output to (M3, M4).

The child screen signal thus signal-processed is displayed as shown in FIG. In FIG. 3, one sub screen / 3 in a television receiver having an aspect ratio of 16: 9
It is an example of a child screen mode. Memory 1 in 1 sub-screen mode
The allocation of M1, M2, M3, and M4 is used as the memory for the first, second, third, and fourth fields.

In the memory allocation in the triple screen mode, M1 is used for the upper screen, M2 is used for the center screen, M3 is used for the lower screen, and M4 is used for the even field of any one moving image. To use.

By the way, when displaying a moving image in the three-screen mode, the vertical frequency of the sub-screen differs between the NTSC system and the high-definition broadcasting system, so that the timing of writing and reading and the sub-screen and the main screen are different. The following problems occur in the state of odd and even fields.

Here, FIG. 4 shows the control timing of the triple screen mode. For example, it is assumed that the write control circuit 5 stores in advance the still images represented by P1, P2, and P3 in the memories M1, M2, and M3, respectively, before the state shown in the drawing.

First, when the still image / moving image switching signal is "H", all three screens are in the still image state, and the read control circuit 9 causes the still image P to be displayed in the order of the upper part, the center, and the lower part of the screen.
1, P2, and P3 are read within the one field period of the main screen.

Next, when a moving image is designated in the center of the three screens by the moving image position designation signal and the still image / moving image switching signal is set to "L", the sub-screen odd / even field discriminating circuit 10 The write control circuit 7 sequentially writes the image signal to the memory M2 for the odd field and the memory M4 for the even field.

At this time, the read control circuit 5 directly reads P1 and P3 as the image signals at the upper and lower parts of the screen, but at the start of reading the image signal at the central part,
The following control is performed according to the discrimination signal from the parent screen odd / even field discrimination circuit 11 and the memory occupation signal from the write control circuit 7.

More specifically, referring to the block diagram of FIG. 2, at time T1, the control signal from the write control circuit 7 writes the image signal P4 in the memory M4, and the control from the parent screen field discrimination circuit is performed. Since the signal is an odd field, the data P2 of the memory M2 is unchanged.
A control signal is sent from the read control means 22 to read

Next, at time T2, the write control signal occupies the memory M2, and the parent screen is an even field, so the data P4 in the memory M4 is read out by the control means 22.
Controls reading. The times T3 and T4 are similarly controlled.

However, at time T5, when the parent screen is an odd field, the write control occupies the memory M2 to be read. In this case, therefore, the data P6 written in the even field of the memory M4 is used as the parent of the odd field. Must be read on the screen.

Similarly, at time T6, since the write control occupies the memory when the parent screen is the even field, the data P7 of M2 written in the odd field must be read to the parent screen of the even field.

At this time, in order to prevent the image signals of the odd field and the even field of the child screen from being reversed, writing and reading are performed when the odd / even field discrimination signals of the child screen and the parent screen both indicate the even field. While watching the timing, they are detected, and the read line is output so that the entire read field data is shifted upward by one line and the data of the first line is not output, but the data of the second line is sequentially output. The correction control circuit 23 performs line correction to avoid the image inversion phenomenon. The same control is performed when the moving image positions are the upper part and the lower part.

On the other hand, FIG. 5 is a control timing chart of the one-child screen mode. The write control circuit 6 responds to the discrimination signal from the odd / even field discrimination circuit 10 for the sub-pictures in the memory M.
The image data of the first, second, third and fourth fields are written in the order of 1, M2, M3 and M4.

Then, the reading control means 20 also reads the image data in the order of the memories M1, M2, M3, and M4 in accordance with the discrimination signal of the parent screen odd / even field discrimination circuit 20, but it is likely to read at the start of reading. When the write control occupies the memory to be set, the data of another memory in which the odd / even of the field discrimination can maintain the same relationship must be read.

However, regarding the read address displacement indicated by the dotted line in FIG. 5, when the same memory is accessed by writing and reading, a field overtaking phenomenon occurs after that, and it seems that an image of another field is connected from the middle of the image. The image is deteriorated in various states.

Therefore, as shown in FIG. 5, in the field correction control circuit 21 of the block diagram of FIG. 2, P4, P5, and P6 are output from the outputs of the write control circuit 6 and the child screen / parent screen field discrimination circuits 10 and 11. , P5 one field before is read again, and then P
6, P7 and P8 are read out.

This is an explanation when the field period of the parent screen is shorter than the field period of the child screen. Conversely, when the field period is long, the same control can be performed by reading out one field data. You can do it.

[0044]

According to the present invention, four field memories for one sub-screen can be used to construct a sub-screen for three screens, and one of the three screens can be used as a moving image without image quality deterioration. In addition, there is a great merit that the 4-field memory can be effectively utilized.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a read control circuit according to the present invention.

FIG. 3 is a diagram of a television screen of the present invention.

FIG. 4 is a diagram showing a write / read timing of a memory when a three-screen mode of the present invention is displayed.

FIG. 5 is a diagram showing the write / read timing of the memory in the single-screen mode display of the present invention.

[Explanation of symbols]

 1 memory 2 switch 3 switch 4 write control circuit 5 read control circuit 6 1 screen mode write control circuit 7 3 screen mode write control circuit 8 1 screen mode read control circuit 9 3 screen mode read control circuit 10 child screen odd / even field discrimination Circuit 11 Parent screen Odd / even field discrimination circuit 12 1 screen / 3 screen mode switching

Claims (4)

[Claims] 1. An image signal of a main parent screen displayed on a television screen is received, and an image signal of a child screen displayed on the television screen smaller than the parent screen is received, Display means for simultaneously displaying the parent screen and the child screen on a television screen, a one-screen display mode for displaying the child screen for one screen on the display means, and the child screen for the parent screen On the other hand, in the television receiver including a mode designating means for designating a three-screen display mode for displaying on the display means for three screens and a field memory for four fields for storing image information of the sub-screen, According to the designation of the mode designation means, the image information of the screen uses all the four fields of the memory in the one-screen mode, and uses the memory for the two fields in the three-screen mode for each one field. To use to display a still image, remaining one screen 2
A television receiver characterized in that a moving image is displayed using the fields. 2. The television receiver according to claim 1, wherein the three-screen mode of the mode specifying means has a three-screen still image mode specifying function, and when the three-screen still image mode is specified, the three-screen mode is selected. A television receiver characterized in that a still image is displayed by using one field for each of three screens of memory. 3. The television receiver according to claim 1, wherein a parent screen field discriminating means for discriminating a field of the parent screen, a child screen field discriminating means for discriminating a field of the child screen, and the child screen Write control means for controlling the timing of writing the image signal to the memory, read control means for controlling the timing of reading the image signal written to the memory, and read the child screen image signal of the moving image in the three-screen mode from the memory. A television receiver comprising: a parent screen field discriminating means and a child screen field discriminating means, and a correcting means for discriminating field overtaking and correcting the read control means. 4. The television receiver according to claim 1, wherein a parent screen field discriminating means for discriminating a field of the parent screen, a child screen field discriminating means for discriminating a field of the child screen, and the child screen Write control means for controlling the timing of writing the image signal in the memory, read control means for controlling the timing of reading the image signal written in the memory, and read out the child screen image signal of the moving image in the single screen mode from the memory. A television receiver comprising: a parent screen field discriminating means and a child screen field discriminating means, and a correcting means for discriminating field overtaking and correcting the read control means.