JPH0983958A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a television receiver with a replay function for reproducing and displaying the image of past several sec and to improve the quality of a replayed reproduced image. SOLUTION: This receiver is provided with a coding and decoding circuit 10 in which the image is encoded, stored into a memory, read from the memory and decoded. At the time of replying, LPF is switched from a second LPF 2 with a characteristic corresponding to the image of real time to a third LPF 12 with a characteristic corresponding to image encoding, and the gain and the peaking frequency of the contour correction of a second contour correction circuit 8 are switched from a characteristic corresponding to the real time image to a characteristic corresponding to the image encoding. Thus the quality of the real time image is maintained appropriately ashereto fore but the quality of the reproduced picture deteriorated by the image encoding is improved at the time of replaying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver, and more specifically, it has a function of reproducing an image by encoding the image, storing it in a memory, reading it from the memory and decoding it. Regarding a television receiver.

[0002]

2. Description of the Related Art A conventional television receiver has two television images of different channels or a television image and a V image.
There is a so-called two-screen television that splits a screen and displays a reproduced image reproduced in TR at the same time.

FIG. 15 is a block diagram showing the structure of such a two-screen TV. The two-screen TV divides the screen into left and right parts and displays a main image and a sub-image.

For example, video signals of a main image and a sub-image obtained by receiving and demodulating television broadcasts of different channels are transmitted through the first and second LPFs 1 and 2 to the first and second AA.
After being converted into digital video signals by the / D conversion circuits 3 and 4, respectively, horizontal thinning is performed by the first and second horizontal thinning / interpolation filter circuits 5 and 6 to reduce the horizontal size to 1/2. together are, the thinned band-limited by the interpolation filter to reduce aliasing distortion according to is carried out, further, the first, the second contour correction circuits 7 and 8 ₀ being performed in the horizontal direction contour correction image quality improvement Is
The main / sub switching signal is output via the switching circuit 9, so that the main image and the sub image are simultaneously displayed on the left and right of the screen.

By the way, when watching an important part of a television, for example, there are times when it is desired to go back a few seconds and review it. In order to meet such a demand, it is conceivable to provide a so-called replay memory to store images and instantly reproduce images for the past few seconds. Even if it takes a few seconds, a large-capacity memory is required. Therefore, in order to realize it with a small memory capacity, it is necessary to perform image coding (compression) / decoding (decompression).

[0006]

Therefore, for example, in the two-screen TV shown in FIG. 15 described above, by encoding the sub-image, storing it in the memory for replay, and reading it from the memory and decoding it, the past It may be possible to provide a replay function that can play back images for a few seconds, but image encoding causes image blurring and noise, which deteriorates image quality, and the characteristics are set according to normal real-time images. The second LPF 2 and the second contour correction circuit 8 ₀ shown in FIG. 15 have a drawback in that the reproduced image at the time of replay cannot be made into an appropriate image quality.

The present invention has been made in view of the above technical problems, and has a function of reproducing an image by encoding the image and storing it in a memory, and reading it from the memory and decoding it. It is an object of the present invention to improve deterioration of a reproduced image due to image coding in a television receiver provided with.

[0008]

In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the television receiver of the present invention according to any one of claims 1 to 6 is provided at an A / D conversion circuit for A / D converting a video signal and at a front stage or a rear stage of the A / D conversion circuit. A filter circuit, an encoding / decoding circuit for encoding and storing the A / D converted digital video signal in a memory, reading out from the memory and decoding, and inputting to the encoding / decoding circuit The selection means for selecting and outputting the digital video signal or the digital video signal output from the encoding / decoding circuit, and the contour correction circuit to which the digital video signal from the selection means is input are provided. Depending on the selection, the gain or peaking frequency of the contour correction of the filter circuit and the contour correction circuit may be individually switched or a combination thereof may be switched. It is configured to.

Further, the television receiver of the present invention according to claims 7 to 12 includes first and second A / D conversion circuits for A / D converting the video signals of the main image and the sub-image, respectively. A first and a second filter circuit, which are respectively provided in front of or behind the first and second A / D conversion circuits, and an A / D
First and second processing circuits for respectively thinning and band limiting the converted digital video signals of the main image and the sub image, and a first input of the digital video signals processed by the first and second processing circuits, respectively. , A second contour correction circuit, and a television receiver for switching and outputting digital video signals from the first and second contour correction circuits to perform dual-screen display of a main image and a sub-image. And a coding / decoding circuit for coding and storing the digital video signal corresponding to the A / D-converted sub-image in a memory, and reading and decoding from the memory, and the coding / decoding. Selecting means for selecting and outputting to the second contour correction circuit the digital video signal corresponding to the sub-image input to the circuit or the digital video signal output from the encoding / decoding circuit. In response to selection of said selection means, switching the second filter circuit, a gain or peaking frequency of the contour correction of said contour correction circuit separately,
Alternatively, it is configured to switch them by combining them.

According to the television receiver of the present invention as set forth in claims 1 to 6, there is provided an encoding / decoding circuit for encoding the digital video signal and storing it in the memory, and reading it from the memory for decoding. Since it is provided, so-called replay becomes possible by displaying the reproduced moving image from the encoding / decoding circuit when an important part is missed and it is desired to go back and review the past few seconds.

In addition, the real-time moving image that does not pass through the encoding / decoding circuit and the reproduced moving image from the encoding / decoding circuit have the filter characteristics of the filter circuit, the contour correction gain of the contour correction circuit, or Since the peaking frequencies are switched individually or in combination, the real-time moving image can maintain the proper image quality as before, while the image quality of the reproduced moving image whose image quality has deteriorated due to encoding can be maintained. Can be improved. That is, by switching the filter characteristics of the filter circuit, noise due to encoding can be reduced, and by changing the contour correction gain or peaking frequency of the contour correction circuit, blurring due to encoding can be corrected. It is possible to reduce noise.

According to the television receiver of the present invention described in claims 7 to 12, in a so-called two-screen TV, the digital video signal of the sub-image is encoded and stored in the memory, and read from the memory and decoded. Since it has an encoding / decoding circuit for encoding, if you want to miss important points and go back a few seconds to review the sub-image, display the replayed moving image from the encoding / decoding circuit. This enables so-called replay.

Moreover, the filter characteristics of the filter circuit, the contour correction gain of the contour correction circuit, or the real-time moving image that does not pass through the encoding / decoding circuit and the reproduced moving image from the encoding / decoding circuit. Since the peaking frequencies are switched individually or in combination, the proper image quality can be maintained for real-time moving images in the same way as in the past, while the quality of reproduced moving images whose image quality has deteriorated due to encoding can be maintained. Can be improved. That is, by switching the filter characteristics of the filter circuit, noise due to encoding can be reduced, and by changing the contour correction gain or peaking frequency of the contour correction circuit, blurring due to encoding can be corrected. It is possible to reduce noise.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[Embodiment 1] FIG. 1 is a block diagram of a television receiver according to Embodiment 1 of the present invention.
The same reference numerals are attached to the portions corresponding to the conventional example of No. 5.

The television receiver of this embodiment is a two-screen TV that displays a main image and a sub-image by splitting the screen into two left and right screens, and like the above-described conventional example, the main image and the sub-image. First and second LPFs corresponding to the respective video signals
1, 2, first and second A / D conversion circuits 3 and 4, and first and second
First and second horizontal thinning / interpolation filter circuits 5 and 6 as a second processing circuit, first and second contour correction circuits 7 and 8, and
A first switching circuit 9 for switching and outputting the digital video signals from the first and second contour correction circuits according to the main / sub switching signal.

In the television receiver according to the first embodiment, a so-called replay function is added to the sub-image so that a moving image for the past several seconds, for example, 5 seconds can be reproduced and displayed by operating a replay key (not shown). And
Therefore, in the preceding stage of the second contour correction circuit 8, the digital video signal from the second horizontal thinning / interpolation filter circuit 6 is coded (compressed) and stored in the memory, and read from the memory and decoded (expanded). Image coding / decoding circuit 10 is provided, and a real-time digital video signal from the second horizontal thinning / interpolation filter circuit 6 or a reproduced digital video signal from the image coding / coding circuit 10 is selected. A second switching circuit 11 is provided as a selection unit for outputting the output.

As described above, although the memory capacity is reduced by the image encoding / decoding to enable the replaying of the moving image for the past 5 seconds at a relatively low cost, the image encoding causes the replay as described above. In addition, the image quality is deteriorated due to image blurring and noise, and the reproduced image at the time of replay cannot be made to have an appropriate image quality.

Therefore, in the first embodiment, in order to solve such a problem, a third LPF 12 for image coding having a filter characteristic different from that of the second LPF 2 is provided, and the output of the second LPF 2 or the output of the third LPF 12 is A third switching circuit 13 for switching and outputting to the second A / D conversion circuit 4 is provided depending on whether it is a real-time image or a replay image at the time of replay, that is, in response to switching selection of the second switching circuit 11. The contour correction gain and peaking frequency of the second contour correction circuit 8 are switched by a contour correction setting signal depending on whether the image is a real-time image or a reproduced image during replay.

In place of the second switching circuit 11,
The transfer data may be selected using the bus.

FIG. 2 shows the second LPF 2 and the third LPF 1.
It is a figure showing the filter characteristic of No. 2, in which the line A shows the characteristic of the 3rd LPF 12, and the line B shows the 2nd L.
The characteristic of PF2 is shown.

The third LPF 12 has a filter characteristic that does not pass a higher frequency component than the second LPF 2 corresponding to a real-time image, thereby reducing noise due to image coding and improving image quality.

Like the second switching circuit 11, the third switching circuit 13 shown in FIG. 1 is controlled to be switched by an image coding switching signal, and when the replay image is taken in, the output of the third LPF 12 is output. The second LPF 2 is output to the second A / D conversion circuit 4, and otherwise the output of the second LPF 2 corresponding to the real-time image is output to the second A / D conversion circuit 4.

At the time of replay, the second contour correction circuit 8
The contour correction setting signal sets the contour correction gain and peaking frequency corresponding to the playback image.In normal times other than during replay, the contour correction setting signal sets the contour correction gain and peaking frequency in a real-time image. The characteristic is set to the same as the corresponding conventional one.

FIG. 3 is a diagram showing the characteristics of the second contour correction circuit 8. When the digital video signal from the second horizontal thinning / interpolation filter circuit 6 is input, the second contour correction circuit 8 has the same characteristic as the conventional one indicated by the broken line corresponding to the real-time image, Coding/
At the time of replay when the digital video signal from the decoding circuit 10 is input, as shown by the solid line, the third LPF 12
The peaking frequency is switched from pf ₁ to pf ₂ according to the filter characteristics of the above, and the contour correction gain is switched to a higher gain.

By thus increasing the contour correction gain of the second contour correction circuit 8, blurring due to image coding can be corrected, and the peaking frequency can be switched according to the filter characteristic of the third LPF 12. As a result, the effect of blur correction can be further enhanced, noise can be reduced, and the image quality of a reproduced image at the time of replay can be made appropriate.

FIG. 4 is a diagram showing the configuration of the second contour correction circuit 8, and FIG. 5 is a signal waveform diagram of each part.

The contour correction circuit 8 includes first to fourth delay circuits 14 to 17 formed of flip-flops, and fourth and fifth delay circuits.
Switching circuits 18 and 19 and first to third adder circuits 20 to
22 and a gain setting circuit 23 described later,
A gain control signal and a frequency switching signal as the above-mentioned contour correction setting signal are given.

The first delay circuit 14 delays the input signal shown in FIG.
5 further delays the output of the first delay circuit 14 by a time T and outputs the output. The fourth switching circuit 18 outputs the first delay circuit 14
Alternatively, the output of the second delay circuit 15 is switched to the third delay circuit 16 and output.

The third delay circuit 16 includes the first switching circuit 1
The output of 8 is delayed by time T and then output to output the fourth delay circuit 17
Outputs the output of the third delay circuit 16 further delayed by time T, and the fifth switching circuit 19 switches and outputs the output of the third delay circuit 16 or the fourth delay circuit 17 to the first adding circuit 19.

The first adder circuit 20 includes the input signal shown in FIG. 5 (A) and the fifth switching circuit 1 shown in FIG. 5 (C).
The outputs of 9 are added to halve the amplitude, which is then inverted to output the signal shown in FIG. Second adder circuit 21
Outputs the signal shown in FIG. 5E to the gain setting circuit 23 by adding the output of the first addition circuit 20 and the output of the fourth switching circuit 18, and the gain setting circuit 23 uses the gain control signal to output the signal. The gain is adjusted and output as shown in FIG.
And the output of the fourth switching circuit 18 are added by the third adding circuit 22 and output. The contour correction gain can be changed according to the gain.

In this embodiment, the peaking frequency for contour correction is switched by switching the fourth and fifth switching circuits 18, 19 by the frequency switching signal to switch the pulse width for contour correction.

FIG. 6 is a diagram showing a detailed configuration of the gain setting circuit 23 of FIG.

In this embodiment, the gain of the 7-bit input X is varied by the 3-bit (1, m, n) gain control signal.

The gain setting circuit 23 includes a first AND gate group 24 to which the gain control signal of the most significant bit 1 and each input of 7 bits are input, the gain control signal of the middle bit m, and the upper 6 bits. 2 and AND gate group 25 to which each of the inputs of the above is input, and a third AND gate group 2 to which the gain control signal of the least significant bit n and each input of the upper 5 bits are respectively input.
6, and a first addition circuit group 27 for adding each 7-bit output of the first AND gate group 24 and each 6-bit output obtained by adding a carry-out output to the 6-bit output of the second addition circuit group 28. , A second addition circuit group 28 for adding each 6-bit output of the second AND gate group 25 and each 6-bit output obtained by adding the low-level high-order bit to the 5-bit output of the third AND gate group 26 And a 7-bit output obtained by adding a carry-out output to the 6-bit output of the first addition circuit group 27 is the output Y of the gain setting circuit 23.
It is said.

According to this embodiment, the gain of the output Y with respect to the input X can be varied by setting the gain control signal, and its coefficient is given by the following equation.

Y = lX + (1/2) mX + (1/4) nX = {l + (1/2) m + (1/4) n} X According to this embodiment, it is shown in FIG. 7 (A). By setting the value of the 3-bit gain control signal for the input X, the gain of the output Y can be set in 8 steps as shown in FIG. 7B. At "4", the input X becomes the output Y with the same amplitude.

As described above, in the first embodiment,
By the real-time image and the replay image at the time of replay,
While switching the second and third LPFs 2 and 12, the second
Since the peaking frequency of the contour correction circuit 8 and the gain of the contour correction are switched, the real-time image can have an appropriate image quality as in the conventional case, and the reproduced image at the time of replay can be reduced in blurring and noise caused by image coding. Then, the proper image quality can be obtained.

In the first embodiment, the first to third LPFs are used.
Although 1, 2, 12 are provided in front of the first and second A / D conversion circuits 3 and 4, as another embodiment of the present invention, as shown in FIG. / first to 3LPF1 ₁ in the subsequent stage of the D conversion circuit 3, 4, 2 _1, 12 ₁ may be provided with. Second and third LPF in this case
The characteristics of the filters 2 ₁ and 12 ₁ are basically the same as those of the first embodiment.

[Second Embodiment] FIG. 9 is a block diagram of a television receiver according to a second embodiment of the present invention.
The same reference numerals are given to the portions corresponding to the first embodiment.

In the first embodiment described above, the second LPF 2 corresponding to the real-time image, the third LPF 12 corresponding to the replay image at the time of replay, and the second and third LPF 2, 2 depending on whether it is the real-time image or the replay time. Although the third switching circuit 13 for switching and outputting the output of 12 is provided, in the second embodiment, a single fourth LPF 29 capable of switching the filter characteristic is provided instead of them, whereby the third switching circuit 13 is provided. The configuration is simplified.

The fourth LPF 29 is responsive to the image coding switching signal to generate the second LPF in the first embodiment.
The second characteristic or the characteristic of the third LPF 12 can be switched.

The fourth LPF 29 is, for example, as shown in FIG.
As shown in (A), the coil L, the first to third capacitors C1 to C3, and the analog switch 30 may be used, or as shown in FIG. It may be configured by the fourth and fifth capacitors C4 and C5 and the analog switch 30.

In the fourth LPF 29 of FIG. 10A, the analog switch 30 is off in the real-time image to which the image coding switching signal is not given, and the coil L and the first and second capacitors C1 and C2 are used. With the characteristics of the second LPF 2, and in the replayed image at the time of replay in which the image coding switching signal is given, the analog switch 30 is turned on and the coil L and the first to third
The characteristics of the third LPF 12 are provided by the capacitors C1 to C3.

In the fourth LPF 29 of FIG. 10B, the analog switch 30 is off in the real-time image to which the image coding switching signal is not given, and the second L is connected by the resistor R and the fourth capacitor C4.
With the characteristics of PF2, the reproduced image at the time of replay in which the image coding switching signal is given, the analog switch 30 is turned on, and the resistor R and the fourth and fifth capacitors C are provided.
The characteristics of the third LPF 12 are obtained by 4, 4 and C5.

The other structure is the same as that of the first embodiment.

Also in the second embodiment, as in the first embodiment, the real-time image can have an appropriate image quality as in the conventional case, and the reproduced image at the time of replay is
Blurring and noise caused by image coding can be reduced to obtain an appropriate image quality.

In the second embodiment, the first and fourth LPFs are used.
Although 1 and 29 are provided in front of the first and second A / D conversion circuits 3 and 4, as another embodiment of the present invention,
As shown in FIG. 11, the first and fourth LPFs _{1 1} and 29 ₁ may be provided at the subsequent stage of the first and second A / D conversion circuits 3 and 4. The characteristics of the filter of the fourth LPF 29 _{1 in} this case are basically the same as those of the second embodiment.

[Third Embodiment] FIG. 12 is a block diagram of a television receiver according to a third embodiment of the present invention. The portions corresponding to those in the first embodiment of FIG. 1 are designated by the same reference numerals.

In the first embodiment described above, at the time of replay,
Although the gain and the peaking frequency of the second contour correction circuit 8 are switched by the contour correction setting signal, in the third embodiment, the second contour correction circuit 8 is similar to the conventional example.
The gain and the peaking frequency of the contour correction of ₀ are not changed and are set to correspond to the real-time image, thereby simplifying the configuration. Other configurations are similar to those of the first embodiment.

According to the third embodiment, the second and third LPs
Since the characteristics of F2 and F12 are switched as in the first embodiment, it is possible to reduce noise due to image coding and improve image quality during replay.

Of course, the second and third LPFs 2 and 12 may be constituted by a single fourth LPF 29, as in the second embodiment.

[Fourth Embodiment] FIG. 13 is a block diagram of a television receiver according to a fourth embodiment of the present invention. The portions corresponding to the first embodiment in FIG. 1 are designated by the same reference numerals.

In the first embodiment described above, the second LPF 2 corresponding to the real-time image, the third LPF 12 corresponding to the reproduced image at the time of replay, and the third switching circuit 13 for switching and outputting those outputs are provided. In the form 4, the second LPF 2 corresponding to the real-time image
Only the filter is provided so as not to switch the characteristics of the filter, thereby simplifying the configuration. Other configurations are similar to those of the first embodiment.

According to the fourth embodiment, like the first embodiment, the contour correction gain and the peaking frequency of the second contour correction circuit 8 are switched, so that blurring due to image coding can be corrected and noise can be reduced. It is possible to improve the image quality during replay.

[Other Embodiments] The above-described first embodiment
In 2 and 4, both the contour correction gain and the peaking frequency of the second contour correction circuit 8 are switched, but as another embodiment of the present invention, the contour correction gain or peaking frequency of the second contour correction circuit 8 is changed. You may switch only one. That is, for the characteristic corresponding to the real-time image shown by the broken line in FIG. 14, only the gain may be switched as shown by the solid line during replay, or only the peaking frequency may be switched as shown by the phantom line. May be.

Further, in each of the above-described embodiments, the replay function is added only to the sub-image, but as another embodiment of the present invention, the main image is also added with the replay function in the same configuration as the sub-image. Good.

In each of the above-described embodiments, the description has been made by applying it to the two-screen TV in which the screen is divided into the left and right, but the present invention only displays the two-screen TV including the main screen and the child screen or the main screen. Of course, it can be similarly applied to a television receiver that cannot.

[0060]

As described above, according to the present invention, coding /
Since the decoding circuit is provided, so-called replay can be performed by displaying the moving image reproduced from the encoding / decoding circuit.

Moreover, the filter characteristics of the filter circuit, the contour correction gain of the contour correction circuit, or the real-time moving image that does not pass through the encoding / decoding circuit and the reproduced moving image from the encoding / decoding circuit. Since the peaking frequencies are switched individually or in combination, the proper image quality can be maintained for real-time moving images as in the past, while the quality of reproduced moving images deteriorated due to noise or blurring due to encoding. Can be improved.

Further, according to the present invention, a so-called two-screen T
In V, it is possible to replay a sub-image and maintain the image quality of a real-time moving image appropriately as in the conventional case, while improving the image quality of a replay reproduced moving image whose image quality is deteriorated by encoding. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram of a television receiver according to a first embodiment of the present invention.

FIG. 2 is a diagram showing filter characteristics of second and third LPFs in FIG.

FIG. 3 is a characteristic diagram of the second contour correction circuit in FIG.

FIG. 4 is a configuration diagram of a second contour correction circuit in FIG.

FIG. 5 is a signal waveform diagram of each unit in FIG. 4;

6 is a configuration diagram of a gain setting circuit of FIG.

FIG. 7 is a waveform diagram for explaining the operation of the gain setting circuit in FIG.

FIG. 8 is a block diagram of a television receiver according to another embodiment of the present invention.

FIG. 9 is a block diagram of a television receiver according to a second embodiment of the present invention.

10 is a configuration diagram of a fourth LPF in FIG.

FIG. 11 is a block diagram of a television receiver according to another embodiment of the present invention.

FIG. 12 is a block diagram of a television receiver according to a third embodiment of the present invention.

FIG. 13 is a block diagram of a television receiver according to a fourth embodiment of the present invention.

FIG. 14 is a characteristic diagram of a second contour correction circuit according to another embodiment of the present invention.

FIG. 15 is a block diagram of a conventional example.

[Explanation of symbols]

1, 2 1st, 2nd LPF 3, 4 1st, 2nd A / D conversion circuits 5, 6 1st, 2nd horizontal thinning-
Interpolation filter circuit 7, 8 First and second contour correction circuit 11 Second switching circuit 12 Third LPF 29 Fourth LPF

Claims (12)

[Claims] 1. An A / D conversion circuit for A / D converting a video signal, a filter circuit provided before or after the A / D conversion circuit, and an A / D converted digital video signal encoded. Encoding / decoding circuit for storing in memory and reading from the memory for decoding, and the digital video signal input to the encoding / decoding circuit or digital video output from the encoding / decoding circuit A television comprising: a selecting unit that selects and outputs a signal; and a contour correction circuit to which the digital video signal from the selecting unit is input, and the filter circuit is switched according to the selection of the selecting unit. Receiver. 2. The television receiver according to claim 1, wherein the filter circuit is composed of a plurality of low-pass filters having different filter characteristics, and outputs of the plurality of low-pass filters are switched and selected according to the selection of the selecting means. . 3. The television receiver according to claim 1, wherein the filter circuit is composed of a single low-pass filter, and the filter characteristic of the single low-pass filter is switched according to the selection of the selecting means. 4. An A / D conversion circuit for A / D converting a video signal, a filter circuit provided before or after the A / D conversion circuit, and an A / D converted digital video signal is encoded. Encoding / decoding circuit for storing in memory and reading from the memory for decoding, and the digital video signal input to the encoding / decoding circuit or digital video output from the encoding / decoding circuit A selection unit for selecting and outputting a signal; and a contour correction circuit to which the digital video signal from the selection unit is input, and switching the contour correction gain of the contour correction circuit according to the selection by the selection unit. Television receiver characterized by. 5. An A / D conversion circuit for A / D converting a video signal, a filter circuit provided in a stage before or after the A / D conversion circuit, and an A / D-converted digital video signal encoded. Encoding / decoding circuit for storing in memory and reading from the memory for decoding, and the digital video signal input to the encoding / decoding circuit or digital video output from the encoding / decoding circuit A selection unit for selecting and outputting a signal; and a contour correction circuit to which the digital video signal from the selection unit is input, the peaking frequency of the contour correction circuit being switched according to the selection by the selection unit. And a television receiver. 6. The television receiver according to claim 1, wherein at least one of a contour correction gain and a peaking frequency of the contour correction circuit is switched according to the selection by the selection means. 7. A first and a second A / D conversion circuit for A / D converting the video signals of the main image and the sub-image, respectively, and a front stage and a rear stage of the first and second A / D conversion circuits, respectively. First and second filter circuits, first and second processing circuits for respectively thinning and band limiting the A / D converted digital video signals of the main image and the sub image,
The first and second contour correction circuits to which the digital video signals processed by the second processing circuit are respectively input, and the digital video signals from the first and second contour correction circuits are switched and output to output the main image and the sub-image. In a two-screen display television receiver, the digital video signal corresponding to the A / D-converted sub-image is encoded and stored in a memory and read from the memory before the second contour correction circuit. And a digital video signal output from the encoding / decoding circuit corresponding to the sub-picture input to the encoding / decoding circuit, and the digital video signal output from the encoding / decoding circuit. A television receiver, comprising: a selection means for selecting and outputting to two contour correction circuits, and switching the second filter circuit according to selection by the selection means. 8. The television according to claim 7, wherein the second filter circuit is composed of a plurality of low-pass filters having different filter characteristics, and outputs of the plurality of low-pass filters are switched and selected according to the selection of the selecting means. Receiver. 9. The television receiver according to claim 7, wherein the second filter circuit is composed of a single low-pass filter, and the filter characteristic of the single low-pass filter is switched according to the selection of the selecting means. 10. A first and a second A / D conversion circuit for A / D converting the video signals of the main image and the sub-image, respectively, and a stage before or after the first and second A / D conversion circuits, respectively. First and second filter circuits, first and second processing circuits for respectively thinning and band limiting the A / D converted digital video signals of the main image and the sub image,
The first and second contour correction circuits to which the digital video signals processed by the second processing circuit are respectively input, and the digital video signals from the first and second contour correction circuits are switched and output to output the main image and the sub-image. In a two-screen display television receiver, the digital video signal corresponding to the A / D-converted sub-image is encoded and stored in a memory and read from the memory before the second contour correction circuit. And a digital video signal output from the encoding / decoding circuit corresponding to the sub-picture input to the encoding / decoding circuit, and the digital video signal output from the encoding / decoding circuit. A second contour correction circuit for selecting and outputting the contour correction circuit, and the contour correction gain of the second contour correction circuit is switched according to the selection of the selection means. Receiver. 11. A first and second A / D conversion circuit for A / D converting video signals of a main image and a sub image, respectively, and a first stage and a second stage of the first and second A / D conversion circuits, respectively. First and second filter circuits, first and second processing circuits for respectively thinning and band limiting the A / D converted digital video signals of the main image and the sub image,
The first and second contour correction circuits to which the digital video signals processed by the second processing circuit are respectively input, and the digital video signals from the first and second contour correction circuits are switched and output to output the main image and the sub-image. In a two-screen display television receiver, the digital video signal corresponding to the A / D-converted sub-image is encoded and stored in a memory and read from the memory before the second contour correction circuit. And a digital video signal output from the encoding / decoding circuit corresponding to the sub-picture input to the encoding / decoding circuit, and the digital video signal output from the encoding / decoding circuit. And a selecting means for selecting and outputting to the two contour correcting circuits, and switching the peaking frequency of the second contour correcting circuit according to the selection of the selecting means. Receiver. 12. The second according to the selection of the selecting means.
10. The television receiver according to claim 7, wherein at least one of a contour correction gain and a peaking frequency of the contour correction circuit is switched.