JP2672719B2 - Television signal transmission system and reproducing apparatus thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal transmission system and a reproducing apparatus therefor in which cross color interference is eliminated.

[0002]

2. Description of the Related Art Conventionally, in the NTSC color television transmission system, I and Q signals are transmitted as color subcarriers fsc.
A color television signal that is balanced-modulated by and is multiplexed in the frequency region overlapping the luminance signal is used.

[0003]

In the conventional NTSC color television signal, as described above, I,
Since the Q signal is multiplexed in the frequency region overlapping the luminance signal, it is impossible to completely separate the luminance signal and the I and Q signals on the receiver side. Therefore, there is a problem that interference such as cross color or cross luminance occurs in the reproduced image, and the image quality of the reproduced image is deteriorated.

[0004]

In order to solve the above problems, the present invention solves the above problems by band limiting means for band limiting the color difference signals or I, Q signals in the horizontal and vertical directions, and band limiting by the band limiting means. Means for compressing the color difference signal or the I, Q signals in the horizontal and vertical directions, and a color signal composed of the color difference signals or the I, Q signals compressed by the compressing means for the vertical overpass without changing the aspect ratio of the television signal. A configuration is provided in which multiplex means for multiplexing in the scan area is provided.

Further, the two color difference signals or the I and Q signals are band-limited in the horizontal and vertical directions and, after being compressed, modulated by a color subcarrier to change the aspect ratio of the television signal.
Without overlapping the vertical overscan area.
In a reproducing apparatus for a large television signal, a separating means for separating a color signal multiplexed in the overscan area after detection of a received color television signal, and a demodulating means for demodulating the color signal separated by the separating means When the interpolation color signal demodulated by the demodulating means in the horizontal and vertical directions, an interpolation-expanding means for expanding, the YC separating means for separating a luminance signal Y from the color television signal after the detection, the interpolation and expansion The color signal derived from the means and the matrix means for obtaining the R, G and B television signals from the luminance signal Y are provided.

[0006]

On the transmitting side, the color difference signals or the I and Q signals are band-limited and compressed, and then modulated by the color subcarrier f _SC and multiplexed in the vertical overscan region of the television signal to obtain one of the television signals. Sent as a copy. This
When, the aspect ratio is unchanged. Eg aspect
A video signal with a ratio of 4: 3 has the aspect ratio of 4: 3 as it is.
Sent. Therefore, the effective luminance signal is not deleted.
In addition, a vertical audio signal into which the color difference signals or I and Q signals are inserted.
The bar scan area remains unchanged. When this television signal is received by the receiving side, after detection of the video signal, the color signal multiplexed in the vertical overscan area of the video signal is separated and demodulated, then interpolated and expanded to reproduce the reproduced color. Become a signal. This color signal is led to the matrix means together with the luminance signal separated from the television signal, and R,
It is derived as G and B signals.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, the transmitting side will be described. FIG.
FIG. 3 is a block diagram of an embodiment of an encoder unit used on the transmitting side in the television signal transmission system of the present invention.
In the figure, 2 is R (red) from the input terminal 1. G
(Green). An NTSC encoder circuit 3 that converts a B (blue) signal into an NTSC television signal and outputs an I and Q signal is a two-dimensional low-pass filter that band-compresses the I and Q signals in the horizontal and vertical directions. (Hereinafter referred to as “LPF”).

Reference numeral 4 is a compression processing circuit for compressing the I and Q signals band-limited by the two-dimensional low-pass filter 3.
Is a balanced modulation circuit that balance-modulates the I and Q signals compressed by the compression processing circuit 4 with the second subcarrier (2.1 MHz). On the other hand, 6 is the above NTSC encoder 2
From the NTSC system television signal, the color signal from the balanced modulation circuit 5 is multiplexed in the vertical overscan area, and a television signal compatible with the NTSC color television system is output to the output terminal T1. It is a vertical overscan multiplexing circuit to be derived.

FIG. 4 illustrates the vertical overscan area used in this embodiment. The overscan area is a portion that does not actually appear as a display, even if a video signal other than the effective screen exists.
The vertical overscan area is located at the top and bottom of the screen indicated by the diagonal lines in the figure. In the present embodiment, a color signal, which will be described later, is inserted in the overscan area instead of the video signal that is conventionally multiplexed.

The encoder section of the present embodiment is constructed as described above, and its operation will be described below. RG input to the input terminal 1 from a television camera (not shown) or the like
The B signal is guided to the NTSC encoder circuit 2, and the NTS
The C encoder circuit 2 converts the signal into an NTSC television signal and guides it to the vertical overscan multiplexing circuit 6, and separates I and Q signals to a two-dimensional LPF 3. 2
In the dimension LPF3, the resolution for color information of the human eye is
Utilizing the fact that it is lower than the resolution for luminance information,
Band limiting the I and Q signals. The horizontal frequency band of the I and Q signals in this state is as shown in FIG.

Bandwidth limited I, Q by the two-dimensional LPF 3
The signals are supplied to the compression processing circuit 4, and the compression processing circuit 4 uses a buffer memory (not shown) or the like to thin out information and perform rearrangement to compress color difference signals. In this case, the pixels are thinned out to 3/4 for each line to be 1
By making the pixels / 4, the time is horizontally compressed to ¼. As a result, the horizontal frequency band becomes as shown in FIG. It should be noted that four time-compressed one lines are rearranged in the horizontal direction so that the original one-line time is obtained. Also, by thinning out the lines for every four lines, the time compression of 1/4 is also performed in the vertical direction. Even if the color signal information is thinned out in this way, there is no problem because the human eye is originally not as sensitive to the luminance as to the luminance.

The compressed I and Q signals are supplied to the balanced modulation circuit 5
To the second subcarrier (2.
The horizontal frequency characteristic becomes a color signal as shown in FIG. 3C by being subjected to balanced modulation using 1 MHz). This color signal is supplied to the vertical overscan multiplexing circuit 6,
The multiplexing circuit 6 multiplexes the signals into the vertical overscan area of the NTSC television signal, and outputs N from the output terminal T1.
It is output as a television signal compatible with the TSC system.

In this embodiment, the I and Q signals are both 0.5 MH.
Although the band up to z is transmitted, it is also possible to increase the compression rate in the compression processing circuit 4 to transmit a color signal in a higher band. It is also possible to perform digital multiplexing by using a predictive coding method, a transform coding method, or the like for the image compression technology.

Next, the receiving side will be described. FIG. 2 is a block diagram of the television signal reproducing apparatus of this embodiment. In FIG. 2, reference numeral 7 denotes an input terminal for receiving a television signal from the transmitting side, detecting the detected television signal, and then converting it to a baseband, and 8 denotes an input terminal 7
It is a vertical overscan separation circuit for separating a signal multiplexed in a vertical overscan area from a television signal supplied to. Reference numeral 9 is a YC separation circuit for separating the luminance signal Y from the television signal, and 10 is balanced demodulation of the signal multiplexed in the vertical overscan area separated by the vertical overscan separation circuit 8 to obtain I and Q signals. A balanced demodulation circuit 11 for demodulation is an interpolation / expansion processing circuit that interpolates and expands the I and Q signals from the balanced demodulation circuit 10 in the horizontal and vertical directions to restore the original I and Q signals.

Reference numeral 12 is a matrix circuit for deriving R, G and B signals to an output terminal T2 from the luminance signal Y from the YC separation circuit 9 and the I and Q signals from the interpolation / expansion processing circuit 11. The television signal reproducing apparatus according to this embodiment has the above-mentioned configuration, and its operation will be described below. The television signal from the transmitting side received by the main unit is
After being detected by a detection circuit (not shown), it is converted into a baseband, and the television signal converted into the baseband is input from the input terminal 7 to the vertical overscan separation circuit 8
Supplied to The vertical overscan separation circuit 8 separates the signal multiplexed in the vertical overscan region from the received signal, guides the separated signal to the balanced demodulation circuit 10, and supplies the main signal to the YC separation circuit 9. The YC separation circuit 9 separates only the luminance signal and supplies it to the matrix circuit 12. On the other hand, in the balanced demodulation circuit 10, the balanced-modulated I and Q signals are demodulated and derived as I and Q signals. Then, the I and Q signals are supplied to the interpolation / expansion processing circuit 11. The interpolating / expanding processing circuit 11 interpolates and expands the input I and Q signals in the horizontal and vertical directions to restore the original color signals and supplies them to the matrix circuit 12. The matrix circuit 12 creates RGB signals from the input luminance signals Y, I and Q signals, and outputs high-definition RGB signals to the output terminal T2.
Derive a television signal.

In the present embodiment, color difference signals such as RY and BY may be used instead of the I and Q signals. Also,
The color signal in the current NTSC signal is multiplexed in the effective screen area, because this is because compatibility with the current television receiver is taken into consideration. If such compatibility is not taken into consideration, the effective screen area Since it is not necessary to multiplex the color signal in the area, in that case, there is almost no cross-luminance interference in which the color signal is mixed with the luminance signal.

[0017]

According to the present invention, since the color signal multiplexed in the overscan area is temporally separated from the luminance signal existing in the effective screen area, cross color interference caused by mixing the luminance signal into the color signal is prevented. It is possible to improve the quality of the reproduced image. Further, if the receiver using the color difference signal processing method according to the present invention becomes mainstream and compatibility with the current television receiver does not have to be considered, the color signals multiplexed in the effective screen area can be used. It is also possible not to transmit the signal, and in that case, it is possible to eliminate the cross-luminance interference in which the color signal is mixed with the luminance signal, and the problem of the Y / C separation is eliminated. Furthermore, according to the present invention, it is possible to increase the compression rate of the color signal and to widen the band of the color signal as compared with the current NTSC system, so that the image quality can be improved. Moreover, the aspect ratio remains unchanged.
So, for example, a video signal with an aspect ratio of 4: 3
It will be sent as it is with the aspect ratio of 4: 3,
Therefore, the effective luminance signal is not scraped and can be reproduced.
You.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a block diagram of a main part on a transmission side.

FIG. 2 shows an embodiment of the present invention and is a block diagram of a main part on the receiving side.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is an operation explanatory diagram of the present invention.

[Explanation of symbols]

 3 Two-dimensional LPF 4 Compression processing circuit 5 Balanced modulation circuit 6 Vertical overscan multiplexing circuit 8 Vertical overscan separation circuit 9 YC separation circuit 10 Balanced demodulation circuit 11 Interpolation / expansion processing circuit 12 Matrix circuit

Claims (2)

(57) [Claims] 1. A band limiting means for band limiting a color difference signal or I, Q signals in horizontal and vertical directions, and a color difference signal or I, Q signals band limited by the band limiting means in horizontal and vertical directions. And a multiplexing means for multiplexing the color difference signals or the color signals consisting of I and Q signals compressed by the compression means in the vertical overscan area without changing the aspect ratio of the television signal. A television signal transmission system. 2. The aspect ratio of a television signal is changed by band-limiting the two color difference signals or the I and Q signals in the horizontal and vertical directions and compressing the modulated color subcarrier.
Instead of the color
In the revision signal reproducing apparatus, after detecting the received color television signal, a separating means for separating the color signals multiplexed in the overscan area, and a demodulating means for demodulating the color signals separated by the separating means, demodulated interpolation color signal demodulated by means in the horizontal and vertical directions, an interpolation-expanding means for expanding, the YC separating means for separating from the luminance signal Y color television signal after the detection, from said interpolation and expansion means A television signal reproducing apparatus comprising: a color signal derived and a matrix means for obtaining R, G, B television signals from the luminance signal Y.