JP3081060B2 - Multi-screen display high-definition 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 display high-definition television receiver capable of simultaneously displaying a plurality of images on a common screen.

[0002]

2. Description of the Related Art As a method for compressing a transmission signal band of a television signal, a multiplex sub-sample transmission method using offset sub-sampling between fields and between frames is known. As one of the multiple sub-sample transmission systems, MUSE (Multiple Sub-Ny) is used.
A so-called "quist sampling encoding" has been proposed, for example, as described in JP-A-61-264889.

FIG. 5 shows a processing circuit (encoder) on the transmitting side in the MUSE transmission system. In FIG. 1, an input signal supplied to an input terminal 1 is sampled by an A / D converter 2 at a sampling frequency of 48.6 MHz and converted into a digital signal. FIG. 6A shows the signal band at this time. In FIG. 6, the horizontal axis represents the horizontal component H and the vertical axis represents the vertical component V.

[0004] The digital output signal converted by the A / D converter 2 is supplied to an inter-field prefilter 3. As a process of a still image area in the inter-field pre-filter 3, as shown in FIG. 6B, a high frequency component is removed in a diagonal direction of the screen.

The output signal of the inter-field prefilter 3 is supplied to a sub-sampling circuit 4. In the sub-sampling circuit 4, an inter-field offset sub-sampling is performed at a sampling frequency of 24.3 MHz. In this case, the signal in the band of 12.15 MHz or more is folded, and the signal band becomes as shown in FIG. 6C.

The output signal of the sub-sampling circuit 4 is supplied to a sampling frequency conversion circuit 5 at the next stage.
The sampling frequency is from 24.3 MHz to 32.4
Converted to MHz. In this case, the signal band remains as shown in FIG. 6C.

On the other hand, the output signal of the A / D converter 2 is
It is supplied to the in-field pre-filter 6. In the intra-field prefilter 6, the processing of the moving image area is performed, and the band is limited to 12.15 MHz as shown in FIG. 6D.
The output signal of the in-field pre-filter 6 is supplied to a sampling frequency conversion circuit 7, and the sampling frequency is converted from 48.6 MHz to 32.4 MHz. In this case, the signal band remains as shown in FIG. 6D.

The output signals of the sampling frequency conversion circuits 5 and 7 are supplied to a linear mixing circuit 8. Also, A
The output signal of the / D converter 2 is supplied to the motion detection circuit 9. In the motion detection circuit 9, a non-linear process is performed on the absolute value of the difference between frames to detect a motion amount. The detection signal of the motion detection circuit 9 is supplied to the linear mixing circuit 8 as a control signal. The linear mixing circuit 8 controls the sampling frequency conversion circuit 5 at a rate corresponding to the amount of motion.
And 7 output signals are mixed.

The output signal of the linear mixing circuit 8 is supplied to a sub-sampling circuit 10, which performs offset sub-sampling between frames at a sampling frequency of 16.2 MHz. In this case, the signal band of the still image system as shown in FIG. 6C is 8.1M.
The frequency band above Hz is folded back, as shown in FIG. On the other hand, the signal band of the moving image system as shown in FIG.
The band of 1 MHz or more is turned back to be as shown in FIG.

The output signal of the sub-sampling circuit 10 is converted into an analog signal by a D / A converter 11, and then is led out to an output terminal 13 via a transmission line filter 12 and sent out to a transmission line. This transmission path filter 12
Has cosine roll-off characteristics at 8.1 MHz.

A high-definition television receiver which receives the above-mentioned MUSE transmission signal and performs multi-screen display has already been proposed in US Pat. No. 4,982,288. FIG.
FIG.

A digitized first high-definition television transmission signal is supplied to a switch 2 via a first input terminal 20.
1 and the frame memory 22. The switch 21 switches between an input signal from the first input terminal 20 and a frame delay signal from the frame memory 22 to perform frame interpolation. The signal interpolated between the frames is supplied to a field interpolating circuit including a field memory 24 and an interpolating circuit 25, and interpolated between the fields to form a still image signal.

On the other hand, the input signal applied to the first terminal 20 is supplied to a field interpolation circuit 26, which performs a field interpolation to form a moving picture signal. The signal interpolated between the frames is directly supplied to one terminal of the motion detection circuit 23, and further supplied to the other terminal via the frame memory 22. A motion detection signal is formed from an inter-frame difference between the two signals. The motion detection signal from the motion detection circuit 23, the still image signal from the interpolation circuit 25, and the moving image signal from the field interpolation circuit 26 are supplied to a linear mixing circuit 27, and a still image is generated in accordance with the motion detection signal. The image signal and the moving image signal are linearly mixed to form a first image signal. The circuit up to this point is the first video signal processing circuit 28 that performs normal signal processing of the main screen in the high-definition television receiver.

A digitized second MUSE transmission signal is applied to a second input terminal 29, and the second MUSE transmission signal is
The E transmission signal is supplied to a field interpolation circuit 30 to derive a moving image signal on which a field interpolation process has been performed. By this moving image processing, the aliasing component of the moving image portion shown in FIG. 6F is restored to the original, and the signal band becomes as shown in FIG. 8B.

On the other hand, the aliasing component of the still picture portion shown in FIG. 6E is not restored, and the aliasing signal band remains as shown in FIG. 8A. An input signal from the second input terminal 29 is also supplied to a second control circuit 33, and a write timing to a memory included in the time axis compression circuit 32 is generated in synchronization with a synchronization signal included in the input signal. Then, the video signal subjected to the field interpolation processing and supplied to the time axis compression circuit 32 in response to the write timing signal is written to the memory.

An input signal supplied from the first input terminal 20 is also supplied to a first control circuit 31, and the time base compression circuit 3 is synchronized with a synchronization signal included in the input signal.
2. A read timing to a memory provided in the memory 2 is generated, and a time axis compressed signal is read from the memory of the time axis compression circuit 32 in accordance with the read timing signal, and a second video signal consisting only of a moving image signal is generated. To form
Field interpolation circuit 3 for forming the second video signal
0, time axis compression circuit 32, first and second control circuits 31,
The circuit composed of the signal 33 is the signal processing circuit 34 for the child screen.

The first signal from the signal processing circuits 28 and 34
The second video signal is supplied to an insertion circuit 35, and a multi-screen high-definition television signal in which the second video signal is included in a small area in the first video signal is output to an output terminal 36.

[0018]

According to the above prior art,
Since the video signal of the child screen is composed only of the moving image signal obtained by the field interpolation processing, there is no aliasing component in the moving image area as shown in FIG. 8B, but in the still image area, the aliasing component as shown in FIG. 8A. Is not restored. For this reason, there is a drawback that the image in the still image area of the child screen becomes an image whose S / N is visually deteriorated due to the aliasing noise of the signal band. SUMMARY OF THE INVENTION It is an object of the present invention to reduce aliasing noise of a video signal of a small screen with a simple circuit configuration.

[0019]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a video signal at a predetermined sampling frequency.
After sampling and converting to a digital signal,
Fold at half the frequency of the sampling frequency
Receiver that receives the returned high-definition television video signal
A is, multi-screen display and high-definition television receiver so as to display a portion of the master screen and the second high-definition television video signal for the sub screen displaying a first high definition television video signal In the above, the input second high-definition television video signal for the small screen is stored in a frame memory.
The second high-definition that has been updated and input
Television video signal and read from the frame memory
Video signal alternately for each frame.
Ri the repeating frequency range by performing the interpolation process between frames or
Interpolating processing means for deriving a still image signal restored in step 1, and first control means for generating a first clock signal synchronized with a synchronizing signal included in the first high-definition television video signal A second control unit for generating a second clock signal synchronized with a synchronization signal included in the second high-definition television image signal; A second high-definition television video signal written by a second clock from the second control means, and a memory controlled to be read by a first clock from the first control means; Time axis compression means for compressing the time axis of the second high-definition television image signal read from the memory in accordance with the size of the child screen; A configuration in which a and interpolation means interpolating the high-definition television video signal to the first high-definition television video signal for the main picture.

In addition to the above structure, a motion detecting means for comparing the second high-definition television video signal with the immediately preceding frame to derive a motion detecting signal from an inter-frame difference,
Field interpolation processing on the high-definition television video signal, and a field interpolation means for deriving a video signal subjected to the field interpolation processing, and a motion detection signal from the motion detection means Mixing means for mixing the still image signal subjected to the frame interpolation processing and the moving picture signal subjected to the field interpolation processing; and a second clock from the second control means for outputting the mixing means output signal. And a memory controlled so as to be read by the first clock from the first control means, and the time of the second high-definition television video signal read from the memory according to the size of the child screen. The time axis compression means for compressing the axis is provided.

[0021]

According to the above arrangement, the high-definition television video signal of the small picture has a still image portion having a return component of 12.15M in the frame interpolation processing by the frame interpolation processing means.
Hz, it is possible to reduce the deterioration of the S / N of the small-screen video signal due to the aliasing component in the low band of the signal band, and to sharpen the small-screen video when performing multi-screen display. be able to.

The high-definition television video signal of the small picture is restored to 12.15 MHz in the still image portion by frame interpolating processing by frame interpolating processing means, and is also processed by field interpolation processing means. The video signal subjected to the field interpolation processing is derived, and the aliasing component of the video portion is completely restored.

The folded portion is 12.15 MHz.
The still image signal restored up to this point and the moving image signal whose aliasing portion has been completely restored are mixed by the mixing means using the motion detection signal detected by the motion detection means to generate a signal for a child screen. Therefore, since the aliasing component of the moving image signal is completely restored, there is no S / N degradation due to the aliasing component, and the S / N degradation due to the aliasing component of the still image signal is reduced.
It is possible to further sharpen the image of the child screen when the multi-screen display is performed.

[0024]

1 and 3 are block diagrams showing different embodiments of the present invention. 1 and 3, the portions corresponding to those of the conventional example shown in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted. First, a first embodiment of the present invention will be described with reference to FIG.

The first video signal processing circuit 28 is the same as the conventional example. The digitized second MUSE transmission signal applied to the input terminal 29 is supplied to a frame interpolation circuit including a switch 40 and a frame memory 41. The switch 40 performs switching between an input signal from the input terminal 29 and a frame delay signal from the frame memory 41 to perform frame interpolation processing.

By this frame interpolation processing, FIG.
2A is restored to 12.15 MHz and becomes the signal band shown in FIG. 2A. The aliasing component of the moving image portion shown in FIG. 6F is not restored, and the aliasing signal band remains as shown in FIG. 2B. However, the deterioration of the S / N of the video signal due to the return of the signal band is largely affected by the still image portion where the return exists even in the low frequency component.

Therefore, in the first embodiment, since the aliasing component of the still picture portion is restored to 12.15 MHz, the influence of the aliasing component in the low frequency band is reduced, and the deterioration of the S / N of the video signal is also reduced. Is done. The signal interpolated between frames forms a second video signal via the time axis compression circuit 32. The operations of the first control circuit 31, the second control circuit 32, and the insertion circuit 35 are the same as in the conventional example.

The switch 40, the frame memory 41,
First and second control circuits 31 and 33 and time axis compression circuit 32
The circuit composed of the signal processing circuit 42 for the small picture in the first embodiment of the present invention.

FIG. 3 is a block diagram of a second embodiment of the present invention. In FIG. 3, a first video signal processing circuit 28 is the same as the conventional example. The digitized second MUSE transmission signal applied to the input terminal 29 is supplied to a frame interpolation circuit including a switch 40 and a frame memory 41. The switch 40 switches between an input signal from the input terminal 29 and a frame delay signal from the frame memory 41 and performs a frame interpolation process to form a still image signal. By this frame interpolation processing, the aliasing component of the still image portion in FIG. 6E is restored to 12.15 MHz, and becomes the signal band shown in FIG. 4A.

On the other hand, the second M applied to the input terminal 29
The USE transmission signal is supplied to a field interpolation circuit 30, where a field interpolation process is performed to form a moving image signal. By this field interpolation processing, the aliasing component of the moving image portion shown in FIG. 6F is restored, and the signal band becomes as shown in FIG. 4B. Therefore, according to this embodiment, the aliasing component of the still image portion to the low band is reduced, and the aliasing of the moving image portion is restored, so that the S / N deterioration of the video signal of the child screen is further reduced.

The signal interpolated between frames is directly supplied to one terminal of the motion detection circuit 50, and further supplied to the other terminal via the frame memory 41. The motion detection circuit 50 forms a motion detection signal based on the inter-frame difference between the two signals. The motion detection signal from the motion detection circuit 50, the still image signal subjected to the frame interpolation processing from the switch 40, and the field interpolation circuit 3
The moving image signal subjected to the field interpolation process from 0 is supplied to the linear mixing circuit 51, and the still image signal and the moving image signal are linearly mixed according to the motion detection signal.

This linearly mixed video signal is derived via the time axis compression circuit 32 as a second video signal for a small picture. In this case, writing to the memory provided in the time axis compression circuit 32 is performed by a control signal from the second control circuit 33, and reading from the memory is performed by a control signal from the first control circuit 31. This is the same as in the first embodiment. Further, the second video signal for the small screen derived from the time axis compression circuit 32 is supplied to the first circuit by the insertion circuit 35.
In the same manner as in the embodiment, the video signal is inserted at a desired position of the first video signal for the main screen.

In each of the first and second embodiments, the luminance signal is subjected to inter-frame interpolation for a still image portion and field interpolation is performed for a moving image portion. However, the same processing is performed on the color difference signal. In the above embodiment, the sub-screen is described as one screen. However, the same may be applied to a case where a large number of sub-screens are displayed.

[0034]

Since the present invention has the above-described configuration, the aliasing component of the still image signal band of the video signal for the small screen is reduced, and the degradation of the S / N due to the aliasing component can be reduced. A clear child screen display can be performed by the circuit configuration. At the same time, since the folded portion of the moving image signal is completely restored, the S / N does not deteriorate due to the folded component of the moving image signal, and the image of the child screen can be further sharpened.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory diagram of FIG. 1;

FIG. 3 is a block diagram of another embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of FIG. 3;

FIG. 5 is a block diagram of a transmission side.

FIG. 6 is an operation explanatory diagram of FIG. 5;

FIG. 7 is a configuration diagram of a conventional example.

FIG. 8 is a diagram showing a signal band in the small-screen receiving circuit.

[Explanation of symbols]

 Reference Signs List 30 Field interpolation circuit 31 First control circuit 32 Time axis compression circuit 33 Second control circuit 35 Insertion circuit 40 Switch 41 Frame memory 50 Motion detection circuit 51 Linear mixing circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 7/015 H04N 5/45 H04N 5/907

Claims (2)

(57) [Claims] 1. A video signal at a predetermined sampling frequency.
After sampling and converting to a digital signal,
Fold at half the frequency of the sampling frequency
Receiver that receives the returned high-definition television video signal
A is, multi-screen display and high-definition television receiver so as to display a portion of the master screen and the second high-definition television video signal for the sub screen displaying a first high definition television video signal In step (2), the input second high-definition television image signal for the sub-screen is updated and written into the frame memory and input.
The second high definition television video signal
The video signal read from the frame memory is
Interpolation between frames by alternately deriving
Interpolating means for deriving a still image signal restored to the repetition frequency range, and a first synchronizing signal synchronized with a synchronizing signal included in the first high definition television image signal.
A first control means for generating a clock signal of
A second control means for generating a second clock signal synchronized with a synchronization signal included in the high-definition television video signal, and a second interpolating processing performed by the interpolating processing means. Writing the high-definition television video signal with the second clock from the second control means,
A memory which is controlled so as to be read by a first clock from the first control means, and which sets a time axis of a second high-definition television video signal read from the memory in accordance with a size of a small screen. Time axis compression means for compressing, and interpolation means for interpolating the second high-definition television image signal for the small screen read out from the time axis compression means into the first high-definition television image signal for the main screen And a multi-screen display high-definition television receiver. 2. A video signal at a predetermined sampling frequency.
After sampling and converting to a digital signal,
Fold at half the frequency of the sampling frequency
Receiver that receives the returned high-definition television video signal
A is, multi-screen display and high-definition television receiver so as to display a portion of the master screen and the second high-definition television video signal for the sub screen displaying a first high definition television video signal In step (2), the input second high-definition television image signal for the sub-screen is updated and written into the frame memory and input.
The second high definition television video signal
The video signal read from the frame memory is
Interpolation between frames by alternately deriving
Interpolating means for deriving a still image signal restored to the repetition frequency range, and comparing the second high-definition television video signal with the immediately preceding frame to derive a motion detection signal from the inter-frame difference. Motion detection means;
Field interpolation processing on the high-definition television video signal, and a field interpolation means for deriving a video signal subjected to the field interpolation processing, and a motion detection signal from the motion detection means Mixing means for mixing the still image signal subjected to the frame interpolation processing and the moving image signal subjected to the field interpolation processing, and a synchronizing signal synchronized with the synchronizing signal included in the first high-definition television video signal A first control unit for generating a first clock signal; a second control unit for generating a second clock signal synchronized with a synchronization signal included in the second high definition television image signal; Output signal of the second control means from the second control means.
And the first clock from the first control means.
Equipped with a memory controlled to be read by the clock of
Time axis compression means for compressing the time axis of the second high-definition television image signal read from the memory according to the size of the child screen; and a second height for the child screen read from the time axis compression means. Interpolating means for interpolating a high-definition television image signal into a first high-definition television image signal for a main screen. A multi-screen display high-definition television receiver.