JPH0832985A - Television signal processor - Google Patents

Abstract

PURPOSE:To prevent disturbance of a picture due to a clock skew in a video signal by delaying the signal whose extent of delay exceeds a prescribed value by decoding processing so that this signal is about an integral multiple of the field period of an input television signal. CONSTITUTION:Y (luminance) and I and Q (demodulated signals of a color C signal) signals outputted from a letter box decoder 15 are inputted to switches 24 to 26 through delay circuits 54 to 56. Delay circuits 54 to 56 delay the Y, I, and Q signals from the decoder 15 so that differences in extent of delay between these Y, I, and Q signals and Y, I, and Q signals from a sequential scanning conversion circuits 20, 22, and 23 are about integral multiplies of the field period (about one field period). Therefore, a clock skew doesn't exist in the video signal part or the television signal subjected to decoding processing even if a clock skew exists in the vertical synchronizing signal part. Consequently, the disturbance of the picture due to a clock skew in the video signal is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal processing apparatus for selectively displaying a plurality of types of television signals having different aspect ratios on the same screen.

[0002]

2. Description of the Related Art As is well known, the NTSC (National Television System Commi) currently implemented in Japan.
In color television broadcasting by the ttee system, the aspect ratio of the screen is 4: 3. On the other hand, in recent years, H
In DTV (High Definition Television) research, it is known that a horizontally long screen having an aspect ratio of 16: 9 is desirable.

In order to broadcast program material created on a horizontally long screen having an aspect ratio of 16: 9 so that it can be displayed as an image on a television receiver of the current NTSC system, the left and right sides of the horizontally long screen are cut. By doing so, a method of setting the aspect ratio to 4: 3 and a method of displaying a horizontally long screen with an aspect ratio of 16: 9 in the center of the screen with an aspect ratio of 4: 3 and leaving the upper and lower parts as non-image parts are considered. There is.

Of these methods, the latter method is called the letterbox method, and even if an image is displayed on an NTSC television receiver, the program material created with an aspect ratio of 16: 9 is not cut at all. have.
However, the number of effective scanning lines in the NTSC system is about 48.
Since 0 lines / frame, in order to transmit the program material with the aspect ratio of 16: 9 by the letterbox method, 360 lines / frame, which is 3/4 of the effective scanning lines, is only used for the image. Therefore, there is a drawback that the image quality is sacrificed to some extent.

Therefore, recently, it has been proposed to transmit an image quality enhancing signal by using the upper and lower non-image portions of the remaining 120 unused lines / frame. As an example, the Technical Report of the Television Society of Japan Vol.1
7, No. 65, pp19-24, BCS'93-42 (Oct. 1993). According to the system described in this document,
A television receiver capable of reproducing a high-quality image having an aspect ratio of 16: 9 can be configured.

The television receiver described in the above-mentioned document has a configuration only for receiving and reproducing letterbox type television broadcasting. However, an actual television receiver needs to be capable of selectively receiving both the current NTSC television broadcast and the letterbox television broadcast.

FIG. 3 shows a conventional television signal processing apparatus for receiving and reproducing both such NTSC and letterbox television broadcasts. That is, the television signal supplied to the input terminal 11 is input to the switch 12 and is also supplied to the sync separation circuit 13 and the identification circuit 14.

Of these, when a letterbox type television signal is input, the switch 12 outputs the signals corresponding to the upper and lower non-picture portions to the letterbox format decoder 1.
5, the switching control is performed so that the signal corresponding to the main image portion is guided to the Y / C / HH (luminance component / color component / horizontal high frequency component) separation circuit 16. Further, the switch 12 is controlled so as to guide all the television signals to the Y / C / HH separation circuit 16 when a television signal other than the letterbox system is input.

On the other hand, the sync separation circuit 13 separates the horizontal sync signal and the vertical sync signal from the input television signal and outputs the separated sync signal to the deflection circuit 17. The deflection circuit 17 generates a horizontal deflection signal and a vertical deflection signal, respectively, based on the input horizontal synchronization signal and vertical synchronization signal, and outputs the horizontal deflection signal and the vertical deflection signal to a monitor (not shown) via output terminals 18 and 19 to monitor the monitor. Deflection processing is being performed. Further, the discrimination circuit 14 discriminates whether or not the inputted television signal is of the letterbox system, and outputs the discrimination result as a judgment signal.

Here, the above Y / C / HH separation circuit 16
Separates a Y (luminance) signal and a C (color) signal from the input television signal. Also, this Y / C / H
When the input television signal is of the letter box system, the H separation circuit 16 outputs the Y of the HH (horizontal high frequency) signal.
The signal and the C signal are separated and their demodulation processing is also performed.

The Y signal output from the Y / C / HH separation circuit 16 is supplied to the letterbox format decoder 15 and the progressive scan conversion circuit 20, respectively. Also,
The C signal output from the Y / C / HH separation circuit 16 is supplied to the color demodulation circuit 21. The color demodulation circuit 21 demodulates the input C signal to generate an I signal and a Q signal, respectively. Of these, the I signal is supplied to the letterbox format decoder 15 and the progressive scan conversion circuit 22, respectively. Further, the Q signal is supplied to the letterbox format decoder 15 and the progressive scan conversion circuit 23, respectively.

The letterbox format decoder 15, which will be described in detail later, decodes a letterbox type signal and outputs a progressive scanning Y signal, I signal and Q signal. The Y, I, and Q signals output from the letterbox format decoder 15 are supplied to the respective input terminals of the switches 24, 25, and 26, respectively. Further, the Y, I, and Q signals output from the respective progressive scan conversion circuits 20, 22, and 23 are switched by the switches 24 and 2, respectively.
5 and 26 are supplied to the other input terminals.

These switches 24, 25, 26
If the television signal supplied to the input terminal 11 is of the letterbox type based on the determination signal output from the discrimination circuit 14, the letterbox format decoder 1
The matrix circuit 27 outputs the Y, I, and Q signals output from
If the television signal supplied to the input terminal 11 is not of the letterbox type, the Y, I, and Q signals respectively output from the progressive scan conversion circuits 20, 22, and 23 are converted into the matrix circuit 27. The switching is controlled so as to lead to.

The matrix circuit 27 generates three kinds of color signals R, G and B based on the input Y, I and Q signals and outputs them to the monitor through output terminals 28, 29 and 30. There is. This allows the monitor to receive both NTSC and letterbox television signals.
The images are selectively displayed.

Next, FIG. 4 shows details of the letterbox format decoder 15. That is, the input terminal 3
A signal corresponding to the upper and lower non-picture portions of the letterbox type television signal guided by the switch 12 is supplied to 1. Further, the input terminals 32, 33 and 34 are respectively supplied with Y, I and Q signals output from the Y / C / HH separation circuit 16 and the color demodulation circuit 21.

Of these signals, the Y signal supplied to the input terminal 32 is added to the adder circuit 35 and the horizontal HPF (high pass filter).
36, a horizontal LPF (low pass filter) 37, and a motion detection circuit 38. The horizontal HPF 36 is
A frequency component of 1.2 MHz or more is extracted from the input Y signal and output to the motion adaptive scanning line interpolation circuit 39.

Further, the horizontal LPF 37 extracts frequency components of 1.2 MHz or less from the input Y signal,
It is output to the vertical LPF 40 for performing the decoding process of the SSKF (Symmetric Short Kernnel Filters) method. Further, the motion detection circuit 38 receives the input Y
The motion of the image is detected based on the signal, and the motion detection signal is output. Then, the motion adaptive scanning line interpolation circuit 39
On the basis of this motion detection signal, the well-known motion adaptive scanning line interpolation processing is performed on the output of the horizontal HPF 36 to generate an interpolation scanning line, which is output to the adding circuit 41.

On the other hand, the signals of the upper and lower non-picture portions supplied to the input terminal 31 are supplied to the LD / VH separation demodulation circuit 42. The LD / VH separation / demodulation circuit 42 detects the LD from the input signals of the upper and lower non-image parts based on the motion detection signal.
A signal (moving image quality enhancement signal) and a VH signal (still image quality enhancement signal) are separated and demodulated. And
The LD signal output from the LD / VH separation demodulation circuit 42 is supplied to the vertical HPF 43 for performing the decoding process of the SSKF method, and the VH signal is converted to the 3-4 conversion circuit 44.
Is supplied to.

Here, the vertical HPF 43 subjects the input LD signal to vertical processing for decoding processing by the SSKF method, and generates a signal for a main scanning line and a signal for an interpolation scanning line. To do. The signal for the main scanning line is supplied to the adding circuit 35, and the signal for the interpolating scanning line is supplied to the adding circuit 45.

The adder circuit 35 adds the signal of the main picture portion supplied to the input terminal 32 and the signal for the main scanning line output from the vertical HPF 43, and the added output is used as the main scanning line. It is output to the 4 conversion circuit 46. The adder circuit 45 adds the signal for the interpolation scanning line output from the vertical HPF 43 and the output signal of the vertical LPF 40, and outputs the added output to the adder circuit 41.

The adder circuit 41 adds the output signal of the adder circuit 45 and the output signal of the motion adaptive scanning line interpolation circuit 39, and outputs the added output to the 3-4 conversion circuit 46 as an interpolation scanning line. There is. And this 3-4 conversion circuit 4
6 is 3 based on the input main scanning line and interpolation scanning line.
The 3-4 conversion processing for generating four scanning lines from the one scanning line is performed to generate a sequential scanning signal having 480 effective scanning lines, and the signal is output to the adding circuit 47.

On the other hand, the 3-4 conversion circuit 44 subjects the input VH signal to 3-4 conversion processing and progressive scanning conversion processing to generate a progressive scanning signal having 480 effective scanning lines, It is output to the V shift circuit 48. The V shift circuit 48 vertically shifts the frequency of the input signal and outputs it to the adder circuit 47. Therefore, the adder circuit 47 adds the output signal of the 3-4 conversion circuit 46 and the output signal of the V shift circuit 48, and outputs the added output as the Y signal output of the letterbox format decoder 15 via the output terminal 49. Is supplied to the switch 24.

The I and Q signals supplied to the input terminals 33 and 34 are supplied to the 3-4 conversion circuits 50 and 51, respectively. These 3-4 conversion circuits 50 and 51 perform 3-4 conversion processing and progressive scanning conversion processing on the input I and Q signals, respectively, to generate progressive scanning signals with 480 effective scanning lines, The signal is used as the I and Q signal outputs of the letterbox format decoder 15 and output terminals 52 and 53.
Is supplied to the switches 25 and 26 via the.

According to the conventional television signal processing apparatus as described above, when a letterbox type television signal is input, the above-mentioned Television Society Technical Report Vol. 17, No. 65, pp 19- 24, BCS'93-42 (Oct. 1993)
Since the same operation as the system described in (1) is performed, a high-quality image with an aspect ratio of 16: 9 can be reproduced, and even when a normal NTSC television signal is input, it is displayed on the same monitor. be able to.

By the way, the time required for the decoding process is greatly different between when a letterbox television signal is received and when a normal NTSC television signal is received. That is, the decoding process of the letterbox type television signal is performed by the NTSC.
The delay is considerably longer than the time required for decoding the television signal of the system.

As described above, there are two parts where a long delay occurs in the decoding process of the letterbox type television signal. One is a process of rearranging the additional signal multiplexed with the signals of the upper and lower non-image parts to the position of the original image.
One is to convert the number of effective scanning lines from 360 to 480 3
-4 conversion processing. The delay amount in these two processes will be described with reference to FIG.

First, FIG. 5A shows a case where a normal NTSC television signal is input. In this television signal, 240 scanning lines per field are video signals. FIG. 5B shows a case where a letter box type television signal is input. The upper and lower 30 scanning lines per field are non-image areas, and the 180 scanning lines are main image areas.

Then, the additional signals for 180 scanning lines are time-compressed to ⅓ and multiplexed on the scanning lines of the non-image portion, which are present in 60 lines per field. Of the additional signals for 180 scanning lines, the additional signals to be multiplexed on the upper 90 lines are multiplexed on the 30 scanning lines on the upper non-image part, and should be multiplexed on the lower 90 lines. The signals are multiplexed on the 30 scanning lines in the lower non-image area.

Therefore, in order to return all the additional signals multiplexed on the 60 scanning lines in the upper and lower non-image areas to their original positions,
A delay of 90 scanning lines is required at the minimum. The reason for this is that as shown in FIG.
Of the 80 scanning lines, the additional signal to be multiplexed to the lower 90 scanning lines is multiplexed to the 30 scanning lines of the lower non-image area, so that the additional signal is input only to the lower non-image area. This is because the lower 90 additional signals can be obtained.

Therefore, by performing a process of rearranging the additional signals multiplexed on the scanning lines of the upper and lower non-image parts to the positions of the original image, a delay of about 90 scanning lines, that is, about 90 lines occurs. . Further, when the 3-4 conversion process and the progressive scan conversion process are performed, an image of 480 effective scanning lines is obtained at the timing shown in FIG. 5D, and thus the NTSC system shown in FIG. Compared with the case of the television signal of, the delay of 120 lines, that is, about 1/2 field period is generated.

Now, consider a case where a television signal reproduced by a VTR (video tape recorder) or the like is supplied to the conventional television signal processing apparatus shown in FIG. In a television signal reproduced by a VTR or the like, clock skew occurs in the vertical sync signal portion. In the case of the television signal of the current system, since the delay due to the decoding process is small, this clock skew exists in the synchronizing signal portion and the clock skew does not affect the video signal portion.

However, when the letter box type television signal is decoded, it is delayed by about 1/2 field period, so that there is a clock skew in the video signal portion and the display image is disturbed. There will be problems.

[0033]

As described above, in the conventional television signal processing device, when a signal in which a clock skew occurs in the synchronizing signal portion, such as a television signal reproduced by a VTR, is input. Since a delay of about 1/2 field period occurs in the decoding process of the letterbox type television signal, there is a problem that a clock skew exists in the video signal portion and the image is disturbed.

Therefore, the present invention has been made in consideration of the above circumstances, and even when a signal in which a clock skew is generated in the synchronizing signal portion is input, image distortion due to the clock skew existing in the video signal portion is caused. It is an object of the present invention to provide an extremely good television signal processing device that can be prevented.

[0035]

A television signal processing apparatus according to the present invention includes a plurality of decoding means for performing a decoding process corresponding to a plurality of types of television signals transmitted by different television systems, respectively. Of the signals output from the plurality of decoding means, a signal having a delay amount due to the decoding process exceeding a predetermined amount is delayed with respect to a television signal input to the decoding means so as to be an integral multiple of a field period. And a delay means.

[0036]

According to the above structure, a signal whose delay amount due to the decoding process exceeds a predetermined amount among the signals output from the plurality of decoding means is supplied to the television signal input to the decoding means. Since the delay is made to be an integral multiple of the field period, even if a clock skew occurs in the vertical sync signal portion, the clock skew does not exist in the video signal portion of the decoded television signal, It becomes possible to prevent image distortion due to the presence of clock skew in the video signal portion.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. 1, the same parts as those in FIG. 3 are designated by the same reference numerals. That is, the Y, I and Q signals output from the letterbox format decoder 15 are supplied to the switches 24, 25 and 26 via the delay circuits 54, 55 and 56, respectively. These delay circuits 54, 55 and 56 are used for the letterbox format decoder 15
The Y, I, and Q signals output from the progressive scan conversion circuit 2
The difference in the delay amount from the Y, I, and Q signals output from 0, 22, and 23 is approximately an integral multiple of the field period (in this case, about 1
The field period).

According to the configuration of the above embodiment, the delay amount when the letter box type television signal is decoded is set to about one field period, so that a clock skew occurs in the vertical synchronizing signal portion. However, there is no clock skew in the video signal portion of the decoded television signal, and it is possible to prevent image distortion due to the clock skew in the video signal portion.

Next, FIG. 2 shows another embodiment of the present invention. That is, while the embodiment shown in FIG. 1 receives a progressive scanning television signal, the embodiment shown in FIG. 2 shows an interlaced scanning television signal. When the same parts as those in FIG. 1 are designated by the same reference numerals, the Y signal output from the Y / C / HH separation circuit 16 and the I and Q signals output from the color demodulation circuit 21 are directly switched by the switch 24. , 25, 26.

In this case, in the letterbox format decoder 15 shown in FIG. 4, the 3-4 conversion circuits 44, 46, 5 are used.
The signal of 360 effective scanning lines is converted into a signal of progressive scanning of 480 effective scanning lines by 0, 51. However, in this other embodiment, conversion into a sequential scanning signal is not performed, and the effective scanning line is not converted. The interlaced scanning signal of several 480 lines is output.

With the configuration of the above-mentioned other embodiment,
Similar to the embodiment shown in FIG. 1, even if clock skew occurs in the vertical synchronizing signal portion, the clock skew does not exist in the video signal portion of the decoded television signal, and the clock skew occurs in the video signal portion. It is possible to prevent the image from being disturbed due to the presence of. The present invention is not limited to the above-described embodiments, but can be variously modified and implemented without departing from the scope of the invention.

[0042]

As described above in detail, according to the present invention,
It is possible to provide a very good television signal processing device capable of preventing image distortion due to the presence of clock skew in the video signal portion even when a signal in which a clock skew is generated in the synchronization signal portion is input.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block configuration diagram showing a conventional television signal processing device.

FIG. 4 is a block diagram showing details of a letterbox format decoder of the conventional apparatus.

FIG. 5 is a diagram for explaining a problem of the conventional device.

[Explanation of symbols]

11 ... Input terminal, 12 ... Switch, 13 ... Synchronous separation circuit, 14 ... Identification circuit, 15 ... Letterbox decoder, 16 ... Y / C / HH separation circuit, 17 ... Deflecting circuit, 1
8, 19 ... Output terminal, 20 ... Progressive scan conversion circuit, 21 ...
Color demodulation circuit, 22, 23 ... Sequential scan conversion circuit, 24-2
6 ... Switch, 27 ... Matrix circuit, 28-30 ... Output terminal, 31-34 ... Input terminal, 35 ... Addition circuit, 36
... Horizontal HPF, 37 ... Horizontal LPF, 38 ... Motion detection circuit, 39 ... Motion adaptive scanning line interpolation circuit, 40 ... Vertical LP
F, 41 ... Addition circuit, 42 ... LD / VH separation demodulation circuit,
43 ... Vertical HPF, 44 ... 3-4 conversion circuit, 45 ... Addition circuit, 46 ... 3-4 conversion circuit, 47 ... Addition circuit, 48 ...
V shift circuit, 49 ... Output terminal, 50, 51 ... 3-4 conversion circuit, 52, 53 ... Output terminal, 54-56 ... Delay circuit.

Claims (5)

[Claims] 1. A plurality of decoding means for performing decoding processing respectively corresponding to a plurality of types of television signals transmitted by different television systems, and a delay due to the decoding processing among signals output from the plurality of decoding means. A television comprising: a delay unit for delaying a signal whose amount exceeds a predetermined amount so as to be an integral multiple of a field period with respect to a television signal input to the decoding unit. Signal processing device. 2. A discriminating means for discriminating a system of an inputted television signal, and a selecting means for selectively taking out output signals of the plurality of decoding means or the delay means based on a discrimination result of the discriminating means. The television signal processing device according to claim 1, further comprising: 3. The television signal processing apparatus according to claim 1, wherein the predetermined amount is about 1/2 field period or more. 4. The television system is an NTSC system or a letterbox system.
The described television signal processing device. 5. Decoding means for subjecting an input television signal to a predetermined decoding process, and a signal output from this decoding means to be an integral multiple of a field period with respect to the input television signal. A television signal processing device, comprising: