JP2624782B2 - Television signal transmission method and demodulation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a television signal system, more specifically,
Even the receiver of the current NTSC television signal etc. can receive.
A high-definition image can be obtained if received by a dedicated receiver. A so-called compatible television signal, particularly a television suitable for transmitting signal components missing in the time-vertical frequency domain in an interlaced scanning signal. It relates to the John signal system.

[Conventional technology]

As is well known, in order to improve the vertical resolution of television (hereinafter abbreviated as TV) images,
Transmission using a progressive scanning camera, transmission by interlaced scanning, and conversion by progressive scanning display has been considered. FIG. 2 shows the principle of the frequency spectrum of the time frequency f-vertical frequency v in these cases. That is, the spectrum of the progressive scan camera output (FIG. 2 (a))
Is filtered by a filter as shown in FIG. 2 (b) and transmitted in the state of FIG. 2 (c). At the time of displaying, the state shown in FIG. 2B is again interpolated by the interpolation filter.

[Problems to be solved by the invention]

In the above prior art, no consideration is given to the blocking component in the processing (spatiotemporal filter) from FIG. 2A to FIG. 2B, and there is a problem in reproducibility, for example, when fine horizontal stripes move up and down. .

A main object of the present invention is to transmit a blocking component when a progressive scanning signal is passed through a spatiotemporal filter and further converted to an interlaced signal.

FIG. 3 is an enlarged view for clarifying the relationship between FIGS. 2 (a) and 2 (b). In this figure, the hatched portion 1
Indicates a frequency spectrum transmitted as an interlaced scanning signal, and the dotted portion 2 is blocked by a filter;
Represents a frequency spectrum that is not transmitted. In this case, although the characteristics of the filter are schematically shown, there are various modifications without being particularly limited to such a diamond shape.

An object of the present invention is to realize means for smoothly reproducing a motion by transmitting the blocked component as well.

[Means for solving the problem]

The above object is achieved by transmitting the component 2 using any transmission means.

 Examples of possible transmission media include: (i) a method using another channel.

(Ii) A method of orthogonally modulating a carrier frequency in the same channel.

(Iii) A transmission method using a so-called Fukinuki Hole.

(Iv) A method of removing existing frequency spectrum components and inserting them instead.

(V) A method in which the upper and lower scanning lines in the current screen are cut and inserted instead.

and so on. However, in many cases, there is a limit to the horizontal frequency, so it is necessary to limit the horizontal frequency to, for example, 1.4 MHz.

[Action]

The component blocked by the spatio-temporal filter prior to the interlaced scanning is extracted, and this is transmitted through the aforementioned separate channel or the gap between components in the current TV signal.

Even when the image is received by the conventional receiver, the image quality is not greatly disturbed, and the image can be received by the conventional television receiver, so-called compatibility.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

A signal 10 (corresponding to FIG. 2 (a)) captured by the progressive scanning camera 11 is subjected to a spatio-temporal filter 21 to generate a low-frequency component 1 (corresponding to FIG. 2 (b)) in a spatio-temporal frequency domain. ) Only are removed. This signal is subjected to 2: 1 sub-sampling (extraction) for each scanning line by the switch 22. This signal is converted into a normal TV signal by the time expansion circuit 23.

On the other hand, if the signals 1 and 24 are subtracted from the original signal 10 by the subtraction circuit 24, [vertical-motion] signals 2 and 25 are obtained. This is performed by the switch 26 to perform 2: 1 sub-sampling in the same manner as described above, and the time expansion circuit 27 obtains a signal corresponding to the time expansion circuit 23 in time. This will be further described later.

Here, the delay circuit 28 is for making the delay time equal to that of the spatiotemporal filter 21. In this description, it is shown that the delay element is provided separately. However, actually, the delay element in the spatiotemporal filter 21 is often used as it is.

Now, the output of the time expansion circuit 27 obtained in this way is
29 is modulated by the modulation circuit 32 by the above-mentioned predetermined method, combined with the output signal 30 of the time expansion circuit 23, and transmitted. Here, the delay circuit 31 is used to make the delay in the modulation circuit 32 coincide with the delay as necessary. However, when using another channel, two time enlargement circuits
The outputs of 23 and 27 are transmitted respectively.

Next, a signal spectrum when the [vertical-motion] signal 2, 25 is sub-sampled by the switch 26 will be described.

For signals 1 and 24 transmitted in the conventional manner, switch 22
As shown in FIG. 2 (c),
The spectrum arrangement is as shown in FIG. On the other hand, when the signals 2 and 25 are sub-sampled by the switch 26, the result is as shown in FIG. This can be understood from FIG.

FIG. 4 shows a case where scanning lines in sequential scanning are viewed from the side.

In the figure, assuming that white circles and black circles indicate light and dark, respectively, the frequency is [30 Hz, 525/2 cpH], which is the center of the signal 2 in FIG.

The signal 2 in this case is the signal 1 from the signal of FIG.
(In this case, the DC value in the [fv] region) is subtracted.

Here, when this signal 25 is sub-sampled by the switch 26, a white circle or a black circle is selected.
This is a direct current in the [fv] region. Then, a component due to interlaced scanning is added, and a frequency spectrum as shown in FIG. 2C is obtained.

To add the two signal components as described above through the time expansion circuits 23 and 27, there are, for example, the five methods described above.
These are still used to transmit high-luminance components and side information of a wide aspect screen even today, and may be handled in the same manner.

Here, a case will be described in which the upper and lower scanning lines in (v) are cut off to make that area a non-image portion.

FIG. 5 shows an example of the arrangement of signals when the number of scanning lines effective as a screen is 480, of which 60 are cut from the upper and lower lines and the image signal 1 is sent to 360 in the center. In this case, the aspect ratio is 16: 9 with respect to the current aspect ratio of 4: 3. Here, the dotted line indicates the second field.

Here, numbers from L1 to L360 are assigned to the 360 scanning lines at the center, and the corresponding [vertical-motion] signal 2,29
Into the upper and lower 60.

Since 1/3 compression is performed in the horizontal direction, the horizontal frequency that can be transmitted is 4.2 / 3 = 1.4 MHz. Also, as shown, L1, L
2, L3... Are made to match the relationship of the [fv] region with the image signal at the center.

It is necessary to separate the signal 30 and the signal 29 on the receiving side. For this purpose, the separation may be performed according to each of the above-mentioned methods (i) to (v). The signal 30 is converted into a progressive scan by a conventionally known method, and a [time-vertical] signal is added to reproduce the signal of FIG. 2 (a).

Although the [vertical-motion] signal 29 has a spectral structure as shown in FIG. 2 (c) as described above, it is necessary to return this to this state (FIG. 3). For this purpose, the polarity may be inverted for each scanning line. That is, the [time-vertical] frequency of the inverted polarity is [30 Hz, 525/2 cp
H], the state returns to the above state.

〔The invention's effect〕

According to the present invention, components missing when converting from sequential scanning to interlaced scanning, in particular, at least a low-frequency component in the horizontal direction can be transmitted, so that the vertical resolution is improved, There are effects such as improvement in resolution.

The information to be newly inserted is a high-frequency component, and the position to be inserted has been considered for the insertion of a horizontal high-frequency signal and the like, and can be a compatible high-definition television signal. .

In the present invention, many other modifications are conceivable, for example, as follows.

(1) Although signals are multiplexed by time division multiplexing in FIG. 5, frequency division may be used.

(2) The characteristics of the spatiotemporal filter shown in FIGS. 2 (b), (c) and 3 are merely examples, and there are many possible configurations.

(3) Although the case of the progressive scanning camera is shown, a component corresponding to the spectrum shown in FIG. 3 may be sent in other cases.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG.
FIG. 3 shows a spatio-temporal frequency characteristic when converting from progressive scanning to interlaced scanning, FIG. 3 shows a spectrum newly transmitted in the present invention, and FIG. 4 shows a state of a scanning line corresponding to FIG. FIG. 5 is an explanatory diagram showing an example of multiplexing. 11: progressive scanning camera, 21: spatio-temporal filter, 22, 26,
2: 1 sub-sampling circuit (thinning circuit).

Claims (5)

(57) [Claims] 1. A vertical scanning time signal for converting a main image portion signal by interlaced scanning into a sequential scanning signal on a receiving side as a vertical signal, or a vertical signal of a corresponding vertical scanning image signal as a reinforcement signal. A television signal transmission system for transmitting a frequency component, wherein the [vertical-time]
A television signal transmission system characterized in that only a horizontal frequency low frequency component of frequency components is transmitted using a temporal or frequency gap of an image signal. 2. The horizontal-frequency low-frequency component of the [vertical-time] frequency component is time-compressed in the horizontal time direction, and one time-compressed signal of the horizontal-frequency low-frequency component corresponding to a plurality of scanning lines is provided. 2. The television signal transmission system according to claim 1, wherein the time multiplexed signal is time-multiplexed on the scanning line, and the time-multiplexed signal is multiplexed and transmitted to the non-image area scanning lines at the top and bottom of the screen. 3. The horizontal frequency low-frequency component of the [vertical-time] frequency component is time-compressed in the horizontal time direction, and the time-compressed horizontal frequency low-frequency component signal corresponding to three scanning lines is converted into one signal. 2. The television signal transmission system according to claim 1, wherein time multiplexing is performed on the scanning lines, and the time multiplexed signal is multiplexed and transmitted to the non-image part scanning lines at the top and bottom of the screen. 4. On the transmitting side, the horizontal frequency low-frequency component of the [vertical-time] frequency component of the progressively scanned image signal is time-compressed in the horizontal time direction, and the time-compressed horizontal frequency corresponding to a plurality of scanning lines. A signal of a low-frequency component is time-multiplexed on one scanning line, and the time-multiplexed signal is received on a television signal transmitted by being multiplexed and transmitted to a non-image part scanning line at the top and bottom of the screen,
The signals in the non-image portion period of the television signal are extracted, the time-multiplexed signals corresponding to the individual scanning lines are time-expanded for each scanning line, and combined with the signals of the corresponding scanning lines in the main image portion, and sequentially. A television signal demodulation method characterized by forming a scanning image signal. 5. On the transmitting side, the horizontal frequency low frequency component of the [vertical-time] frequency component of the progressively scanned image signal is time-compressed in the horizontal time direction, and the time-compressed horizontal signal corresponding to three scanning lines. The signal of the frequency low-frequency component is time-multiplexed on one scanning line, and the time-multiplexed signal is multiplexed on the non-image part scanning lines at the top and bottom of the screen and receives the transmitted television signal,
The signals in the non-image portion period of the television signal are extracted, the time-multiplexed signals corresponding to the individual scanning lines are time-expanded for each scanning line, and combined with the signals of the corresponding scanning lines in the main image portion, and sequentially. A television signal demodulation method characterized by forming a scanning image signal.