JP2638175B2 - A color-image chrominance signal multiplex transmission system with compatibility - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-vision transmission system for transmitting a high-vision signal and a television signal of a specific system with a smaller amount of information while maintaining compatibility.

(Summary of the Invention) The present invention relates to a transmission method of a high-definition signal. For example, a video having an aspect ratio of 16: 9 is transmitted while maintaining compatibility with a conventional NTSC signal having an aspect ratio of 4: 3, and an image having an aspect ratio of 16: 9. In the method of creating blank areas without signals above and below the NTSC receiver screen for matching, the horizontal and high frequency components of the two color difference signals of the Hi-Vision signal are field-sequentially applied to the upper and lower blank areas, and the vertical of the luminance signal of the Hi-Vision signal. The signal is multiplexed with the high frequency component or transmitted alone.

Thus, it is possible to transmit a high-definition signal that is compatible with a television signal of a specific system having a smaller amount of information.

(Prior Art) In a television transmission system, various technologies for multiplexing various video signals in a vertical or horizontal blanking period have been proposed so far, but a high-definition television signal of a specific system having a smaller amount of information has been proposed. As a result of the compression scan conversion of the effective scan line and the matching of the aspect ratio for the purpose of providing compatibility with the signal, the high-frequency color signal of the high-definition signal is placed in a blank portion where no signal is formed in the upper and lower portions of the specific type receiver. There is no conventional example in which components are multiplexed.

(Problems to be Solved by the Invention) A high-vision signal has, for example, 1125 scanning lines and an aspect ratio of 16: 9, and an NTSC signal has 525 scanning lines and an aspect ratio of 4: 3. When the broadcasting systems are different as described above, it is premised that the broadcasting is usually transmitted through different transmission paths and the receiver is also different.

In order to transmit a Hi-Vision signal while maintaining compatibility with the NTSC signal, high-definition information of the Hi-Vision signal must be multiplexed into the NTSC signal. A separate application has been filed for the multiplexing of the vertical high-frequency component of the luminance signal of the Hi-Vision signal (Japanese Patent Application No. 63-24009 "Image signal transmission method").
In order to express Hi-Vision video in the NTSC format due to the difference in the aspect ratio of the NTSC signal, create a blank area with no signal at the top and bottom of the screen of the NTSC receiver or match the screen height on the screen of the NTSC receiver described above In such a case, there are two methods of separately transmitting the left and right broken parts.

The purpose of the transmission system of the present invention is to use the former two of the above two systems, and the two color difference signals of the Hi-Vision, alone or together with the vertical high-frequency component of the luminance signal of the Hi-Vision signal, By multiplexing the horizontal high-frequency components in a field-sequential manner, NTSC receivers can play video with an aspect ratio of 16: 9, which is black at the top and bottom, and Hi-Vision receivers can demodulate signals multiplexed in the upper and lower blank areas. In addition, the present invention proposes a color image color difference signal multiplexing transmission system having compatibility capable of reproducing high definition high definition video.

(Means for Solving the Problems) To achieve this object, the compatible color image chrominance signal multiplex transmission system of the present invention has a larger aspect ratio and a larger number of scanning lines than a television signal of a specific system. The number of effective scanning lines of a high-definition signal having a number is compressed and scan-converted into a smaller number of effective scanning lines than the effective scanning lines of a television signal of a specific system, and transmitted. In the method of transmitting a high-definition signal while maintaining the aspect ratio of the high-definition signal, the horizontal high-frequency components of the two color difference signals of the high-definition signal are field-sequentially arranged in a signal blank portion above and below the receiver screen of the specific method, and the luminance signal of the high-definition signal is Multiplexed with or independently of the vertical high-frequency component of the above.

(Embodiment) The band of the NTSC transmission color signal is 1.5 MHz for the I signal and 0.5 MHz for the Q signal. According to the present invention, the color signal to be transmitted is broadened in order to maintain compatibility with the high-definition transmission system. In the high-vision receiver according to the present invention, the I signal is 3 MHz.
It is assumed that the z and Q signals can be reproduced up to 2 MHz. In order to make the color signal compatible, the band of the I signal is 0 to 0.
1.5MHz and 1.5 ~ 3MHz, 0 ~ 0.5MHz for Q signal
The frequency is divided into 0.5 to 2 MHz, the same transmission path as that of the conventional NTSC system is used for the reduction, and the transmission is performed by the method described in detail below for the high band.

Hereinafter, a color signal transmission method according to the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 are block diagrams showing an encoder and a decoder according to an embodiment of the present invention, respectively.

In FIG. 1, the input I signal that has been subjected to the matrix processing is first band-limited to 0 to 3 MHz by an LPF (low-pass filter) 1. This output is further separated into a 0-1.5 MHz signal and a 1.5-3 MHz signal by an LPF 2 of 0-1.5 MHz. The signal of 1.5 to 3 MHz is obtained by subtracting the input and output signals of the LPF 2 by the subtractor 3. This allows 0-1.
The characteristics around 1.5 MHz of the 5 MHz signal and the 1.5 to 3 MHz signal have a complementary relationship. The signal 0~0.5MHz the I signal at thisゝ, NTSC transmission method similar to the color of 3.58MHz via [pi / 2 phase shifter 4 in view of the later of the Q signal subcarrier f _sc modulator 5 in modulated, the adder 12, is transmitted via the switch s _2. 1.5~3MHz signals is the output of the subtracter 3 I signal also modulates the 3.58MHz color subcarrier f _sc in the modulator 6, thereby the signal of the band 0.58~2.08MHz and 5.08~6.58MHz is obtained. Among them, the signal of 5.08 to 6.58 MHz is removed by the LPF 7, and the signal component of 0.58 to 2.08 MHz is obtained at the output of the LPF 7.

On the other hand, the input Q signal that has undergone matrix processing is first LPF8
Is limited to a band of 0 to 2 MHz. Subsequently, the signal is separated into a signal of 0 to 0.5 MHz and a signal of 0.5 to 2 MHz using the LPF 9 and the subtractor 10 in the same manner as the I signal. 0 to 0.5MHz of Q signal
The signal modulates the NTSC color transmission system similar 3.58MHZ subcarrier f _sc in the modulator 11, an adder 12, is transmitted via the switch S _2. For the Q signal component of 0.5 to 2 MHz, NTSC due to the difference in aspect ratio
It is multiplexed in a field sequence on the upper and lower blank portions of the signal.

A high frequency component of which is the output I signal LPF7 the high-frequency component of the Q signal output from the subtracter 10 is switched every field by the switch S _1. Switching between the I signal and the Q signal for each field is equivalent to halving the field frequency. This narrows the band in the direction of motion that can be transmitted. In the case of a still image or a moving image with a small motion, the reproduction signal is not affected even if the field frequency is reduced by half because the band in the motion direction is narrow. For moving video,
Since the high frequency components of the color signal are small, the amount of information to be transmitted is small. Therefore, it is possible to transmit the high frequency components of the color signal in a field sequence.

Then the color signals after the switching, which is the output of the switch S ₁ is time-base-compressed by the time axis compressor 13. The aspect ratio of a high-definition image is 16: 9, while the aspect ratio of an NTSC image is 4: 3. The number of vertical effective scanning lines on the NTSC receiver after signal transmission to maintain compatibility is that if the vertical direction is compressed and the aspect ratio is 16: 9, the upper and lower parts will be blank. Become. This is because the number of vertical scanning lines in an NTSC receiver is considerably smaller than that of 525. A means for assigning the vertical high frequency component of the luminance signal of the effective screen in the center of the screen to the upper and lower blank portions has been separately filed by the present applicant (see Japanese Patent Application No. 63-24009, "Image Signal Transmission System").
In the present invention, the high-frequency component of the color signal of the effective screen in the center of the screen is additionally or separately applied to the upper and lower blank portions by the time axis compressor
At 13 the time axis is compressed and multiplexing is attempted. The reason why the high frequency component of the color signal is compressed on the time axis is that the area of the upper and lower blank portions is reduced to about half that of the central portion of the screen.

For example, to simplify the explanation, the number of scanning lines in the upper and lower blank part is 175, the number of scanning lines in the effective screen is 350, and so on.
Taking 2, the compression ratio of the time axis compression is 1: 2. Under this compression ratio, the output of the LPF 7 is 0.58 to 2.08 of the I signal.
The signal component of MHz has a band of 1.16 to 4.16 MHz, and the signal component of 0.5 to 2.0 MHz of the Q signal output from the subtracter 10 has a band of 1.0 to 4.0 MHz. Since these signals are multiplexed into the upper and lower blank portions, for example, when a carrier f of 4.68 MHz (= 17/13 · f _sc ) is modulated by the modulator 14, the I signal band is 0.52 to 3.52 MHz and 5.84 to 8.84 M
The bandwidths of the Hz and Q signals are 0.68 to 3.68 MHz and 5.68 to 8.68 MHz. Of these, the higher frequency component is removed (the LPF for that is omitted), and the lower component is multiplexed on the upper and lower blank portions and transmitted. That is, in this case, the I signal is 0.52-
As for the 3.52 MHz and Q signal, components of 0.68 to 3.68 MHz are transmitted. Switch S ² is the signal that is output of the adder 12 when the effective screen, when the signal is of the upper and lower blank portions are switched to the output side of the multiplier 14.

When only the high frequency component of the color signal is multiplexed in the upper and lower blank portions, the output C signal thus obtained is multiplexed as it is. When the vertical high-frequency component of the luminance signal is also multiplexed in the upper and lower blank areas, use the bandwidth arrangement between the vertical high-frequency component of the luminance signal to be transmitted and the high-frequency component of the chrominance signal, and use some interleaving techniques. However, since this technique may use a well-known technique, a detailed description thereof will be omitted.

The above is the description of the encoder configuration example according to the transmission system of the present invention. Next, the decoder configuration example will be described with reference to FIG.

Color signal transmitted is switched to the multiplier 24 side by the first switch S ₃ as the input C signal and when the effective screen as when the multipliers 22 and 23 side of the upper and lower blank portions. In this case, when the input C signal is transmitted with the vertical high frequency component of the luminance signal and the high frequency component of the chrominance signal both multiplexed in the upper and lower blank portions, a processing circuit which is deformed at the preceding stage or one dimension is required. In this case, however, a case will be described in which only high-frequency components of a color signal are multiplexed.

At the time of the effective screen, the π / 2 phase shifter 21 and the multiplier 22 are further multiplied by the color subcarrier 3.58 fMHf _{sc in the same} manner as the normal NTSC transmission method.
Thus, the low-frequency component of the I signal is demodulated by the multiplier 23, and the reduced component of the Q signal is demodulated by the multiplier 23. In the upper and lower blank portions, the multiplier 24 multiplies the carrier f having the same frequency as that of the modulation of the high frequency component of the color signal at the time of the encoder to demodulate the high frequency component of the color signal. In the case of the present embodiment, the band of the high band I signal transmitted is
Since the band of the high-frequency Q signal is 0.68 to 3.68 MHz, the frequency f of the carrier wave is 4.68 MHz (= 17/13 · f _sc ).
Then, the band of the signal to be demodulated is 1.16 to 4.
16MHz and 5.84 ~ 8.84MHz, Q signal is 1.0 ~ 4.0MHz and 5.36 ~ 8.3
6MHz. Of these, LPF25 passes only the lower component. Next, time axis expansion is performed by the time axis expander 26. As a result, the signal band of the present embodiment is such that
2.08 MHz and the high band Q signal is 0.5 to 2.0 MHz.

Since the high frequency components of the color signal are transmitted in a field sequence, it is necessary to perform field interpolation. In the case of the configuration example shown in FIG. 2, it is called zero-order interpolation. When the high band I signal is being transmitted, the switch S ₄ is up and the switch is
High band I signal S ₅ becomes lower is sent to the next stage as soon as they are recorded in the field memory 27. When the high band Q signal is being transmitted, the switch S ₄ is down and the switch S ₅ is up, and the high band I signal one field before recorded in the field memory 27 is sent to the next stage. As a result, the high band I signal is transmitted to the next stage without interruption even during the transmission of the high band Q signal. The operation of the field memory 28 is the same as the operation of the field memory 27, and the high-frequency Q signal is transmitted without interruption. High band I signal is demodulated then use the demodulator 29 at the color subcarrier f _sc, the band of the result of high band I signal 1.5 to 3.0
MHz and 4.16 to 5.66 MHz, but the LPF 30 allows lower frequencies to pass. As a result, the high-frequency I signal becomes the same as the high-frequency component 1.5 to 3.0 MHz when separated by the encoder, and the I-signal before encoding is reproduced by adding the low-frequency I signal to the adder 31. Can be. High-frequency Q signal field memories 28, after the switch S ₆ is 0.5 bandwidth
2.0 MHz, which is the same as the high-frequency Q signal when separated on the encoder side, and by adding to the low-frequency Q signal by the adder 32, the Q signal before encoding can be reproduced.

In the above embodiments, the specific method is described as the NTSC transmission method, the number of effective scanning lines in the receiver of the specific method is 350, and the transmission bands of the two color signals of the Hi-Vision signal are 3 MHz and 2 MHz, respectively. However, it is obvious to those skilled in the art that the present invention is not limited to this, and that the present invention can be changed or modified without departing from the scope of the present invention.

(Effects of the Invention) In the conventional NTSC transmission system, the color bands that can be transmitted are I signals of 0 to 1.5 MHz and Q signals of 0 to 0.5 MHz. In the method of the present invention, the aspect ratio is set to 16: 9 instead of 4: 3, and the high frequency range of the color signal is multiplexed in the blank part formed above and below, so that
A conventional 4: 3 aspect ratio receiver can reproduce an effective screen with a 16: 9 aspect ratio black, with the top and bottom black. On a 16: 9 aspect ratio receiver, the I signal is 0 to 3.0 MHz and the Q signal is 0 to
A 2.0MHz wideband color signal can be reproduced.

[Brief description of the drawings]

FIGS. 1 and 2 are block diagrams respectively showing an embodiment of an encoder and a decoder for a color signal portion according to the transmission system of the present invention. 1,30 LPF (0 to 3 MHz) 2 LPF (0 to 1.5 MHz) 3,10 Subtractor 4,21 π / 2 phase shifter 5,6,11,14,22, 23,24,29 Multiplier 7 LPF (0 to 2.1 MHz) 8 LPF (0 to 2 MHz) 9 LPF (0 to 0.5 MHz) 12,31,32 Adder 13 …… Time axis compressor S ₁ , S ₂ , S ₃ , S ₄ , S ₅ , S ₆ … Switch 25… LPF (0 to 4.2 MHz) 26… Time axis expander 27,28… Field memory

Continued on the front page (72) Inventor Shoichi Suzuki 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Research Institute (72) Inventor Taiji Nishizawa 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Within the Broadcasting Corporation Broadcasting Research Institute (72) Inventor Kazuma Enami 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Within the Broadcasting Corporation Research Institute (72) Inventor Yutaka Tanaka 1-110, Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Haruo Okuda 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Research Institute (56) References JP-A-1-200881 (JP, A) Hei 1-258581 (JP, A) JP-A-2-184183 (JP, A)

Claims (5)

(57) [Claims] An effective scanning line of a high-vision signal having a larger aspect ratio and a greater number of scanning lines than a television signal of a specific system has a smaller number of effective scanning lines than an effective scanning line of a television signal of a specific system. In a method of transmitting a high-definition signal while maintaining the aspect ratio of the high-definition method with respect to the receiver of the specific method by transmitting the compression scan conversion to the high-definition method, a high-definition image is formed in a signal blank portion above and below the screen of the specific method. A color image chrominance signal multiplexing with compatibility characterized in that the horizontal high frequency components of two color difference signals of the signal are multiplexed and transmitted in a field-sequential manner together with the vertical high frequency component of the luminance signal of the HDTV signal or independently. Transmission method. 2. A color image chrominance signal multiplex transmission system having compatibility as claimed in claim 1, wherein said specific system is an NTSC transmission system. 3. The color image chrominance signal multiplex transmission system with compatibility according to claim 1 or 2, wherein the aspect ratio of said Hi-Vision signal is 16: 9. 4. The transmission system according to claim 1, wherein the number of effective scanning lines smaller than the number of effective scanning lines of the television signal of the specific system is 350. Multiplexed color image color difference signal transmission system 5. The transmission system according to claim 1, wherein the bands of two color difference signals for transmitting the Hi-Vision signal are 3 MHz and 2 MHz, respectively. Color image color difference signal multiplex transmission method.