JPH06233248A - Video signal processing circuit - Google Patents

Abstract

PURPOSE:To enable a reception by a high quality picture from which an offensive picture-quality disturbance is removed by discriminating whether a reception signal is a present NTSC system or a letter box system EDTV or not and substituting the non-picture part areas of the upper and lower parts of a screen by a mask signal for the television signal of the letter box system EDTV. CONSTITUTION:The television signal V1 of a base band zone are inputted in a discrimination control part 1, a black burst signal generation part 2 and a switch circuit part 3, respectively. The discrimination control part 1 performs the system discrimination (discrimination of an NTSC system or a letter box system EDTV) by detecting the presence or absence of the discriminating signal of an input television signal and the signal processing generating control signals BBF and MSL corresponding to the systems. When the input television signal is the letter box system EDTV, the non-picture part area of the upper and lower parts of a screen where a vertical reinforcing signal is superposed are evenly displayed by black and grey, etc., for instance, because the signals of these non-picture part areas are substituted by mask signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing circuit which is connected to a television receiver to receive an image with little image quality interference, and more particularly, to an image quality which is obtrusive to a television signal of a letterbox EDTV. The present invention relates to a video signal processing circuit suitable for receiving a high-quality image from which interference has been removed.

[0002]

2. Description of the Related Art Having compatibility with the current TV system,
Research and development of EDTVs that provide wider-screen, higher-definition, higher-quality images and provide more realistic TV images are underway. Various systems have been devised to realize this EDTV, and one of them is the letterbox system EDTV.

In this letterbox EDTV, a horizontally long image having a horizontally long aspect ratio different from 4: 3 is transmitted by providing a non-image area above and below the screen to widen the screen. In addition, vertical high-frequency components of luminance are superimposed as vertical reinforcement signals on the upper and lower non-image areas of the screen to achieve high precision and high image quality. The television signal of this system has an advantage that it can receive a landscape image with a landscape aspect ratio even when it is received by a current television receiver (NTSC system), and is promising as a next-generation television system in Japan. Is being watched.

[0004]

When a television signal of a letterbox EDTV is received by a current television receiver, a landscape image with a landscape aspect ratio can be received. However, in the upper and lower non-image areas of the screen, it is expected that an unpleasant image disturbance will occur due to the superimposed vertical reinforcement signals, which may cause viewer discomfort. That is, in the existing television receiver, letterbox method E
When a DTV television signal is received, there is a problem that an unpleasant image quality disturbance occurs.

An object of the present invention is to connect an existing television receiver to an existing television receiver in the form of an adapter capable of receiving a letterbox EDTV television signal with a high quality image without image quality interference. The present invention is to provide a video signal processing circuit.

[0006]

In order to achieve the above object, according to the present invention, a received signal is detected by detecting the presence or absence of an identification signal for a television signal in a baseband band.
A signal processing means for discriminating between the SC system and the letterbox system EDTV is provided. For the television signal of the letter box EDTV, a signal processing means for replacing the upper and lower non-image areas of the screen with a mask signal is provided.

Further, a means for the viewer to select one of a plurality of mask signals having different characteristics is provided.

Further, for the television signal of the letterbox EDTV, the viewer is provided with a means for selecting one of a plurality of display areas on the screen of the horizontally long image portion.

[0009]

In the television signal of the letterbox EDTV, an identification signal indicating the mode of various parameters is added to a predetermined position. Therefore, by detecting the presence or absence of the identification signal of the received television signal, it is possible to accurately discriminate between the NTSC system and the letterbox system EDTV without malfunction.

For a television signal of the letterbox EDTV, mask signals are used to replace the signals in the non-picture area above and below the screen on which the vertical reinforcement signal is superimposed. Therefore, in the existing television receiver, the non-image area is uniformly displayed in, for example, black or gray, and the disturbing image quality disturbance can be completely removed.

Further, in the present invention, since the viewer can select one of a plurality of types of mask signals and one of the display areas of the horizontally long image portion, the letter box can be selected in the existing television receiver according to the viewer's preference. A television signal of the system EDTV can be received.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A video signal processing circuit of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. Further, FIG. 2 is a timing chart of signals in the respective units.

Baseband television signal VI
Are input to the identification control unit 1, the black burst signal generation unit 2, and the switch circuit unit 3, respectively.

The discrimination control unit 1 discriminates a system by discriminating the presence or absence of the discrimination signal of the input television signal (discrimination between the NTSC system and the letterbox system EDTV) and a signal for generating control signals BBF and MSL corresponding to the system. Perform processing.

In the black burst signal generator 2, as shown in FIG.
In accordance with the control signals BBF shown in (2) and (4), the signal component of the video signal portion is a black level application signal for the television signal in the area excluding the vertical blanking period of each field. The signal processing for replacement is performed to generate the black burst signal BB shown in (5) of FIG.

In the switch circuit section 3, either the input television VI or the black burst signal BB is selected by the control signal MSL, and the output television signal VO is selected.
To generate. That is, when the input television signal is the letterbox EDTV, the signal BB is generated during the period of the non-picture area above and below the screen where the vertical reinforcement signal VP is superimposed by the control signal MSL shown in (3) of FIG. Select.
On the other hand, in the period other than this, the signal VI is selected. Then, the horizontally long image portion generates the output television signal VO by replacing the upper and lower non-image portion areas of the signal VM screen having the same component as the input signal with the mask signal of the signal BB. When the input television signal is of the NTSC system, for example, the control signal MSL of which the entire period is low (LOW) is always the signal VI.
Select the same output television signal VO as the input signal
To generate.

When this output television signal VO is displayed on an existing television receiver, an image of a letterbox type EDTV in which the non-image areas at the top and bottom of the screen are uniformly black and the disturbing image disturbance is removed. Can be received.

Next, a second embodiment of the present invention will be described with reference to the block diagram shown in FIG. This is suitable when the viewer selects a plurality of types of mask signals.

The input television signal VI in the baseband band is input to the identification control section 1, the mask signal generation section 5, and the switch circuit section 3.

The identification control unit 1 performs the system discrimination of the NTSC system and the letterbox system EDTV by detecting the presence or absence of the identification signal of the input television signal, and performs the signal processing of generating the control signals BBF and MSL corresponding to the system. .

The masking signal generator 4 generates a plurality of different brightness level signals from black to white, for example, and uses a brightness level signal corresponding to the selection control signal MSCT selected by the viewer as the masking signal MSK. Output.

In the mask signal generator 5, (2) in FIG.
By the control signal BBF shown in (4), signal processing for replacing the signal component of the video signal portion with the signal of the masking signal MSK is performed on the television signal in the area excluding the vertical blanking period of each field. , Mask signal MS is generated.

The switch circuit section 3 selects either the input television signal VI or the mask signal MS according to the control signal MSL to generate the output television signal VO. That is, when the input television signal is the letterbox EDTV, the masking is performed during the period of the region where the vertical reinforcement signal VP of the upper and lower non-image areas of the screen is superimposed by the control signal MSL shown in (3) of FIG. Select the signal MS. Then, in a period other than this region, the signal VI is selected, the horizontally long image portion generates the same signal VM as the input signal, and the upper and lower non-image portion regions of the screen generate the output television signal VO replaced with the mask signal of the signal MS. To do. On the other hand, when the input television signal is the NTSC system, for example, the signal VI is always selected by the low control signal MSL in all the periods, and the same output television signal VO as the input signal is generated.

In an existing television receiver, this signal VO
Is displayed, the non-image areas at the top and bottom of the screen are evenly displayed at the brightness selected by the viewer (for example, any of black, gray, ..., White), and the letter box is displayed without disturbing image quality disturbance. System EDTV images can be received.

Next, the identification control unit 1 in these embodiments will be described with reference to the embodiments shown in FIGS.

FIG. 4 shows the first embodiment, FIG. 4A shows the overall configuration, and FIG.

The input television signal VI is input to the system identification section 6 and the synchronization extraction section 7. In the system identification unit 6, the signal V
A signal component at a predetermined position of I is extracted to detect the presence or absence of an identification signal, and when there is an identification signal, a letter box EDTV is generated, and when there is no identification signal, a system mode signal MOD representing the NTSC system is generated. Further, the sync extraction unit 7 extracts the vertical sync signal VD and the horizontal sync signal HD from the signal VI. In the control signal generator 8, the signals VD, HD, MOD
Accordingly, control signals BBF and MSL corresponding to each method as shown in FIG. 4B are generated. In either method, the control signal BBF generates a signal in which the area of the image signal portion other than the vertical blanking period of each field is HIGH ((2) and (4) in FIG. 2). On the other hand, the control signal MS
L is always in the low (a) form in the case of the NTSC system,
Alternatively, the vertical blanking period of each field and the period of 240 lines of the effective pixel scanning line generate a signal in a low form (b). In the case of the letterbox EDTV, a signal in which the periods of the upper and lower non-image areas of the screen of each field are high is generated. In the case of the NTSC system, by using the control signal MSL of the form (b), the signal component superimposed in the character multiplex broadcasting can be replaced with the mask signal.

FIG. 5 shows a second embodiment, FIG. 5A shows the overall configuration, and FIG. This is suitable when the area replaced by the mask signal of the letterbox EDTV is changed with time.

The input television signal VI is input to the system identification section 6 and the synchronization extraction section 7. In the system identification unit 6, the signal V
A signal component at a predetermined position of I is extracted to detect the presence or absence of an identification signal, and when there is an identification signal, a letterbox type EDTV, and when there is no identification signal, a mode mode signal MOD representing the NTSC system is generated. Further, the sync extraction unit 7 extracts the vertical sync signal VD and the horizontal sync signal HD from the signal VI. In the control signal generator 8, the signals VD, HD, MOD
Based on the above, a control signal similar to that shown in FIG. 4B is generated. That is, the control signal BBF generates a signal in which the area of the image signal portion is high except for the area of the vertical blanking period of each field in any method. Further, the control signal MSL1 is always low in the NTSC system, or the vertical blanking period of each field and the effective pixel scanning line 2
40-line period low, letterbox method E
In the DTV, a signal in which the period in the upper and lower non-image areas of the screen of each field is high is generated. In the wobbling unit 9, in the case of the letterbox type EDTV, the control signal M
SL1 is, for example, the solid line in (b) and (3) of FIG.
As indicated by the broken line in (b), the control signal MSL is generated by performing a fobbling process that temporally changes the area to be replaced with the mask signal by one line. Therefore, since the area replaced by the mask signal of the letterbox EDTV changes temporally without being fixed on the screen, it is possible to suppress the occurrence of a burn-in phenomenon or the like on the display unit of the receiver.

As described above, according to the first and second embodiments, the video signal processing circuit capable of receiving the image of the letterbox type EDTV which is connected to the existing television receiver in the form of an adapter and has no undesired image quality interference. Can be realized at low cost by simple signal processing.

Next, a third embodiment of the present invention will be described with reference to the block diagram shown in FIG. This is suitable for digital signal processing.

Baseband television signal VI
Is input to the identification control unit 1 and the A / D conversion unit 10.

The identification control unit 1 determines the NTSC system and the letterbox EDTV system by detecting the presence or absence of the identification signal of the input television signal, and generates the control signals BBF and MSL necessary for the signal processing corresponding to each system. I do.

In the A / D converter 10, for example, sampling is performed at a frequency four times as high as the color subcarrier fsc and converted into a digital signal VID.

The black burst signal generator 11 performs signal processing in which the control signal BBF replaces the signal of the video signal portion in the area excluding the vertical blanking period of each field with the digital value signal of the black level component. , Generate a black burst signal BBD.

The selection circuit section 12 selects and outputs one of the signals VID and BBD according to the control signal MSL. That is, in the case of the letterbox EDTV, the signal BBD is selected in the periods of the upper and lower non-image areas of the screen of each field, and the signal VID is selected in the periods of other areas. In the case of the NTSC system, the control signal is shown in FIG.
In (b) of (a), the signal VID is selected, and in (b), the signal VID is selected and output during the vertical blanking period of each field and the period of 240 lines of the effective pixel scanning line, and the signal BBD is selected in other periods.

The D / A converter 13 performs digital-to-analog conversion to generate an output television signal VO in which signal components that disturb the image quality are replaced with mask signals.

FIG. 7 is a block diagram of the fourth embodiment of the present invention, which is suitable for the viewer to select the mask signal.

Baseband television signal VI
Is input to the identification control unit 1 and the A / D conversion unit 10.

The identification control unit 1 discriminates the NTSC system and the letterbox EDTV system by detecting the presence or absence of the identification signal of the input television signal, and generates the control signals BBF and MSL necessary for the signal processing corresponding to each system. I do. In the A / D converter 10, for example, sampling is performed at a frequency that is four times the frequency of the color subcarrier fsc and converted into a digital signal VID.

In the masking signal generator 14, for example,
The selection control signal MSCT selected by the viewer is generated by generating digital values of a plurality of different brightness levels from black to white.
The digital value of the corresponding brightness level is output as the masking signal MSKD.

In the mask signal generator 15, the control signal BB
By F, signal processing for replacing the signal component of the video signal portion in the area excluding the vertical blanking period of each field with the signal MSKD is performed to generate the mask signal MSD.

The selection circuit section 12 selects and outputs one of the signals VID and MSD according to the control signal MSL. That is, in the case of the letterbox EDTV, the signal MSD is selected during the period of the upper and lower non-image areas of the screen of each field, and the signal VID is selected and output during the period of other areas. Further, in case of the NTSC system, FIG.
In the control signal of (a) of (3) of (b), the signal VID,
In (B), the signal VID is selected and output during the vertical blanking period of each field and the period of 240 lines of the effective pixel scanning lines, and the signal MSD during the other periods. Then, the D / A conversion unit 13 converts the signal into an analog signal, and generates an output television signal VO in which a signal component that causes an unpleasant image quality is replaced with a mask signal.

The identification control unit 1 in these embodiments
Can be realized by the one shown in FIG. 4 or FIG.

As described above, according to the third and fourth embodiments, the letter box type EDTV which is connected to the existing television receiver in the form of an adapter and does not cause an unpleasant image quality disturbance.
It becomes possible to realize a video signal processing circuit capable of receiving the image.

Next, a fifth embodiment of the present invention will be described with reference to the block diagram shown in FIG. This is suitable for selecting and displaying the horizontally long image portion of the letterbox EDTV at a plurality of different positions on the screen.

The input television signal VI in the base band is input to the A / D converter 10 and the controller 16.

In the A / D converter 10, for example, sampling is performed at a frequency four times as high as the color subcarrier fsc and converted into a digital signal VID. In addition, the control unit 16 determines the NTSC system or the letterbox EDTV system according to the presence or absence of the identification signal of the input television signal, generates the control signal MSL necessary for the signal processing of the mask signal replacement, and the image display mode. Synchronous control signal VSC corresponding to signal DPM is generated.

The mask signal generator 17 selects one of a plurality of digital values of different brightness levels from black to white, for example, according to the selection control signal MSCT selected by the viewer, and outputs the mask signal MSD. To generate.

The selection circuit section 18 selects and outputs one of the signals VID and MDS according to the control signal MSL. That is, in the case of the letterbox EDTV, the signal VID is selected in the period of the horizontally long image portion and the signal MSD is selected in the periods other than this to generate the output signal VS. In the case of the NTSC system, for example, the signal VID is always
To generate the output signal VS.

In the case of the letterbox type EDTV, the process section 19 performs the switching process of the sync signal and the burst signal at a predetermined position according to the sync control signal VSC. Then, for example, as shown in FIG. 8B, the horizontally long image portion is displayed at the central portion of the screen in the standard mode, the upper portion of the screen in the upper mode, and the lower portion of the screen in the lower mode.
The signal VSS in which the position of the synchronization signal system is changed is generated. In the case of the NTSC system, the switching process of these synchronizing signal systems is not performed, and the signal VS becomes the output signal VSS as it is. Then, the D / A conversion unit 13 converts the analog signal into an analog signal, replaces an unpleasant signal component that disturbs the image quality with a mask signal, and outputs an output television signal for displaying the landscape image portion in a screen area selected by the viewer. Generate VO.

FIG. 9 shows an example of the control unit 16 in this embodiment. 9A is a block diagram, and FIG. 9B is a timing chart of control signals in the case of a letterbox EDTV.

The input television signal VI is input to the system identification section 6 and the synchronization extraction section 7. The system identification unit 6 extracts a signal component at a predetermined position of the signal VI to detect the presence or absence of the identification signal. If the identification signal is present, a letterbox system EDTV, and if not, a system mode representing the NTSC system. Generate the signal MOD. Further, the sync extraction unit 7 extracts the vertical sync signal VD and the horizontal sync signal HD from the signal VI.

In the mask control signal generator 20, the signal V
The control signal MSL shown in (2) of FIG. 9B is generated based on D, HD, and MOD. That is, in the case of the letterbox EDTV, a low signal is generated in the region of the horizontally long image portion of each field, and a high signal is generated in the other regions. In the case of the NTSC system, for example, a low signal is always generated.

In the synchronizing signal generator 21, the signals VD and H
According to D, MOD and image display mode signal DPM,
The synchronization control signal VSC shown in (3) of FIG. That is, in the case of the letterbox EDTV, the SYN mode is set according to the standard, upper and lower modes.
A signal indicating the positions of the C signal and the HD signal is generated. Also,
In the case of the NTSC system, a signal corresponding to the standard mode is generated.

According to the present embodiment, an existing television receiver is connected in the form of an adapter so that there is no obtrusive image quality obstruction and the landscape image portion is displayed at a position on the screen selected by the viewer. It becomes possible to realize a video signal processing circuit capable of receiving the image of the box system EDTV.

Next, an embodiment of the connection between the video signal processing circuit according to the present invention and the existing existing television receiver will be described with reference to FIGS.

FIG. 10 is suitable for combination with a television signal in the base band obtained by a current television receiver.

The current television receiver has a tuner section 23, a video intermediate frequency amplification section 24, a video detection section 25, a video amplification section 26, and a video demodulation section 2 as shown in the broken line in FIG.
7, a matrix conversion unit 28, and an image display unit 29. The output signal of the video amplifier 26 is a television signal demodulated in the baseband. Therefore, the video signal processing circuit 22 according to the present invention is connected between the video amplification unit 26 and the video demodulation unit 27 in the form of an adapter. Then, the output signal of the video amplifier 26 is input as the input television signal VI of the video signal processing circuit 22, and the output television signal VO is input to the video demodulator 27.
Then, the image display unit 29 can receive an image of a letterbox EDTV which does not disturb the image quality.

FIG. 11 shows an example of connection by combination with a recording device such as a VCR. The television signal VI in the baseband band obtained from the recording device 30 is input to the video signal processing circuit 22. Then, the output signal VO is input to the external input terminal 31 of the current television receiver, and the signal demodulated by the video demodulation unit 27 and the matrix conversion unit 28 is displayed on the image display unit 29. Then, an image of a letterbox EDTV that does not disturb the image quality is received.

In this way, by connecting the video signal processing circuit of the present invention to the existing existing television receiver in the form of an adapter, a letterbox type ED that does not interfere with image quality is provided.
It can receive TV images.

[0063]

According to the present invention, the letterbox system E
The current NTS for DTV television signals without image quality interference
A video signal processing circuit that can be received by a C television receiver can be realized at low cost by simple signal processing.

[Brief description of drawings]

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

FIG. 2 is a timing chart of signals at various parts in the present invention.

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

FIG. 4 is an explanatory diagram of an embodiment of an identification control unit according to the present invention.

FIG. 5 is an explanatory diagram of a second embodiment of the identification control unit according to the present invention.

FIG. 6 is a block diagram of a third embodiment of the present invention.

FIG. 7 is a block diagram of a fourth embodiment of the present invention.

FIG. 8 is a block diagram of a fifth embodiment of the present invention.

FIG. 9 is an explanatory diagram of a control unit according to a fifth embodiment.

FIG. 10 is a block diagram of an embodiment in combination with a current receiver.

FIG. 11 is a block diagram of an embodiment in combination with a recording device.

[Explanation of symbols]

1 ... Identification control unit, 2 ... Black burst signal generation unit, 3
… Switch circuit part.

Claims (6)

[Claims] 1. A letter for transmitting a horizontally long image having a horizontally long aspect ratio, which is a video signal processing circuit connected to a television receiver having an aspect ratio of 4: 3, in which non-image areas are provided above and below the screen. A signal processing means for discriminating between a television signal of the box type EDTV and a television signal of the current NTSC system by detecting the presence or absence of an identification signal, and a mask signal for the non-picture area above and below the screen of the letter box type EDTV. In the television signal of the letterbox EDTV, the television signal obtained by replacing the non-picture area above and below the screen with a mask signal is used as an output signal. Video signal processing circuit. 2. A video signal processing circuit according to claim 1, wherein one of a plurality of types of signals having different characteristics is selected and used as a mask signal. 3. A video signal processing circuit according to claim 1 or 2, wherein the region replaced by the mask signal is not fixed constantly on the screen but changes temporally. 4. A video signal processing circuit according to claim 1, 2 or 3, wherein a horizontally long image portion of said letterbox EDTV is selected at a plurality of different positions on a screen for display. 5. A video signal processing circuit according to claim 1, 2, 3 or 4, wherein the signal processing is digital. 6. The method according to claim 1, 2, 3, 4 or 5.
A video signal processing circuit that connects to a television receiver with an aspect ratio of 4: 3 in the form of an external adapter.