JPS619094A - Method for processing video signal and its circuit - Google Patents

Abstract

PURPOSE:To prevent the delay in a color difference signal even when both signals are converted repetitively by converting a chrominance signal of color difference simultaneous transmission into a chrominance signal of color difference line sequential transmission with the converting method so that the order of the horizontal period and the order of the color difference line sequence have always a constant relation. CONSTITUTION:A video signal including a chrominance signal with color difference simultaneous transmission is inputted from a video input terminal 1, the signal is decoded into a luminance signal (a) and a color difference signal (b) at a decoder circuit 2 and a horizontal synchronizing signal and a vertical synchronizing signal are extracted from the luminance signal (a) by a synchronizing separation circuit 4. The color difference signal (b) is converted into the 2nd signal (c) of color difference line sequential transmission by using a control signal (i) from a signal changeover circuit 3. In this case, a color difference signal B-Y is assigned to an even number order horizontal period and a color difference signal R-Y is assigned to an odd number order horizontal period in such a case. The luminance signal (a) and the color difference signals obtained in this way are outputted while being subject to frequency multiplex or time multiplex by a mixing circuit 6, and the processing, recording, reproduction and transmission are executed on a transmission line 6.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is directed to converting a color difference line from a video signal that is transmitted simultaneously with color difference, or a signal having a luminance signal and a color signal equivalent thereto (color signal for color difference simultaneous transmission). The present invention relates to a video signal processing method for converting into a signal for sequential transmission (color signal for color difference line sequential transmission) and its circuit.

In other words, the NTSC system, which is the standard television system, and P
In the AL system, one set of two types of color difference signals (named in the NTSC system!) is used in one horizontal period.

, Q Q signal, U in PAL system,
(different from the V signal, but both corresponding to the color difference signals R-Y and B-Y) are simultaneously superimposed and transmitted (this is called color difference simultaneous transmission).

On the other hand, even in the standard television system, SECAM
As in the method, if you look at each horizontal period, one of the two color difference signals, and two that temporally (spatially) follow each other.
Some systems perform color difference line sequential transmission in which two color difference signals are transmitted alternately in one horizontal cycle.

The present invention converts a signal for simultaneous color difference transmission into a signal for color difference line sequential transmission, and then converts this signal back into a signal for color difference simultaneous transmission. The present invention relates to a method and a circuit for repeating a series of conversions between signals.

[Prior art]

The iterative conversion between the conventional color difference simultaneous transmission signal and the color difference line sequential transmission signal will be explained with reference to FIG.

Figure 1 3° 11/Video signal 1/9/6 signal 9.7i
, represents a number indicating the order of the horizontal period starting from the vertical synchronization signal or a signal similar to it, where n represents the n-th horizontal period, the minimum value of n is 1, and the maximum value is NTSC system. Then, in the 525° PAL system, it becomes 625. It is a positive integer.

In the following explanation, 1. In a video signal or a signal similar thereto, the brightness will be explained using the number n in the first figure).゛Figure 1 (bl is the color difference signal (bl) included in each horizontal period of the video signal or similar signal for color difference simultaneous transmission.
(hereinafter referred to as the first signal), and R, n in the figure
is the n-th horizontal cycle, the color difference included in period i (the color difference signal component of R-Y), and Bn is the n-th horizontal cycle,
It shows the color difference signal components of the included color difference signal B-Y.

In general, there is no fixed method for converting a color difference simultaneous transmission signal into a color difference line sequential transmission signal, so from b, suppose that the color difference signal component of the color difference signal B-Y is converted to an odd number in the even horizontal period. A color difference line sequential signal C (hereinafter referred to as a second signal) is shown when the color difference signal component of the color difference signal RY is assigned to the th horizontal period.

Figure 1+d) is the second signal C of the color difference line sequential transmission described above.
The figure shows a signal d (hereinafter referred to as the third signal) created from , and transmitted simultaneously with slight color difference.There are various ways to create this third signal d, but here we will discuss the commonly used method. state

That is, the color difference signal component of the n-th horizontal period (Fig. 1 (
dl (7) Rn-1, Bn) of the nth horizontal period
is in the second signal C! It is created by combining the color difference signal component Bn of the n-th horizontal period and the color difference signal component Rn-, 1 of the (n-1)th horizontal period temporally earlier by one horizontal period. , and before and after that, and in the horizontal period (n-L n+1.), R, B in the above explanation
Next, from the third signal d of color difference simultaneous transmission obtained in Fig. 1(d), the signal e of color difference line sequential transmission shown in Fig. 1(e) (hereinafter , referred to as the fourth signal)
Let us consider a case where the signal f is converted into a color difference simultaneous transmission signal f (hereinafter referred to as the fifth signal).

FIG. 1(e) shows the fourth signal d, which transmits the third signal d again in color-difference line sequential transmission. This shows the case where the signal e is converted into the signal e.

In this case, since the conversion method can generally be chosen arbitrarily,
Here, the color difference signal component of the color difference signal R-Y is applied to the even-numbered horizontal period, and the color-difference signal component of the color difference signal B-Y is applied to the odd-numbered horizontal period.
This shows the case where color difference signal components are assigned.

FIG. 1 (fl shows the case where the fourth signal e is converted into a fifth signal f for simultaneous color difference transmission,
Although various methods of creating this fifth signal f can be considered, a commonly used method will be explained here.

That is, the color difference signal component of the n-th horizontal period (Fig. 1 (
Rn 1 * Bn of the nth horizontal period of fl
2) is one color difference signal component Rn-1 of the nth horizontal period in the fourth signal e, and the color difference signal component of the n-1th horizontal period temporally preceding it by one horizontal period. Bn-2, and in the horizontal period (n-1t n+1) before and after that, R and B in the above explanation are reversed and combined.

In the above explanation, the conversion process of converting a color difference simultaneous transmission signal to a color difference line sequential transmission signal and then converting it again to a color difference simultaneous transmission signal has been performed twice. As a result, some changes occur in the color difference signal components, so next, the changes in the color difference signal components will be described.

First, when comparing the first signal S and the third signal d, which are the same color difference simultaneous transmission, the color difference signal components of the n-th horizontal period are Rn and Bn' in the first signal, but On the other hand,
The third signal d becomes Rn-1 and Bn.

This means that when converting from the first signal to the second signal C, the color difference signal component is halved, and when creating the third signal d for simultaneous color difference transmission, it takes one horizontal period. The color difference signal component in front of the target
This is due to the T complement, and this first signal 5
The zero difference in color difference signal component between the third signal 4 and the third signal 4 occurs in principle as long as the voice changes as described above.

Next, when comparing the third signal d and the fifth signal f, which also transmit the same color difference simultaneously, in the third signal d, as mentioned above, the color difference signal component of the n-th horizontal period is Rn- 1,
Bn, but in the fifth signal f, the horizontal period having the same color difference signal component is the (n+1)th horizontal period.

In other words, each time the conversion process of creating the fifth signal f from the third signal d is repeated, in the example of FIG. It shows that you are falling behind in terms of performance. That is, this result is extremely inconvenient as it may cause color shift when the process involves repeating such a conversion process.

[Summary of the invention]

The present invention has been made in view of the above, and when converting between a signal for color difference simultaneous transmission and a signal for color difference line sequential transmission, the color difference simultaneous transmission signal is By using a conversion method such that the order of color difference lines and the color difference line sequential order always have a predetermined relationship, the signal is converted into a signal for color difference line sequential transmission.
To provide a video signal processing method capable of preventing delays in color difference signals even when a series of conversions is repeated between the above two signals, and a video signal processing circuit for implementing the method. It is an object.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Before explaining the present invention in detail, the cause of the delay in color difference signals as described above will be described.

In the example shown in FIG. 1, when creating the second signal C from the first signal, the color difference signal B-Y is generated in even-numbered horizontal periods.
In contrast, while the color difference signal RY is assigned to the odd-numbered horizontal period, the third signal d to the fourth signal
When creating one signal e, the color difference signal R-Y is generated in the even-numbered horizontal period, and the color-difference signal B- is generated in the odd-numbered horizontal period.
The conversion is performed by assigning Y. In other words, the first and second conversions have opposite odd and even characteristics, and the difference between the first and second conversion methods is as described above. This is the cause of the delay in color difference signals.

Therefore, in the video signal processing method according to the embodiment of the first invention of the present application shown in FIG. The conversion method is the same as the second conversion method used to determine the allocation of color difference signals when creating the fourth signal e from the third signal d, so that the color difference signal as described above is This prevents delays.

The effects of this embodiment will be explained below with reference to FIG.

Figure 2 Ta), (bJ Ha, Figure 1 (a), respectively)
(Since it is the same as bJ, the explanation is omitted here.

' Fig. 2 ((11 is ultimately the same as Fig. 1 (C), but in this embodiment, when converting to color-difference line sequential transmission, the color-difference signal B- Y is always converted so that the color difference signal R-Y is assigned to odd-numbered horizontal periods.
) is different from the conventional example shown in FIG. 1 in that the conversion method is the same as when creating .

Figure 2+d) shows the third signal d of simultaneous color difference transmission in the same way as the third signal d in Figure 1(d) explained earlier.
The details of this method of creation will be omitted here.

FIG. 2(e) shows a signal e (hereinafter referred to as the fourth signal) which is generated from the third signal d shown in FIG. 2(d) and is transmitted in color difference line sequentially. The conversion method in this case is exactly the same as the conversion method used to create the second signal C in FIG. 2(C) above. That is, in this example, the color difference signal component of the color difference signal B-Y is assigned to the even-numbered horizontal periods, and the color-difference signal component of the color difference signal R-Y is assigned to the odd-numbered horizontal periods. .・,1 FIG. 2(f) shows a signal f (hereinafter referred to as the fifth signal) for simultaneous color difference transmission created from the fourth signal e (FIG. 2(e)), Various methods can be considered for creating this fifth signal f, but here we will use a commonly used method to create the fifth signal f (FIG. 2(f)). Color difference signal component (R
n-1, Bn) is the color difference signal component Bn of the n-th horizontal period in the fourth signal e (Fig. 2 (@)) and the n-1-th color difference signal component Bn of the n-th horizontal period temporally previous by one horizontal period. The color difference signal component Rn−1 in the horizontal period is created by the color difference signal component Rn−1 in the horizontal period, and in the horizontal periods before and after that,
, B are created by reversing and combining them.

Here, as in the case of Fig. 1, Fig. 2(d), (f
) Comparing the third signal d and the fifth signal f, which carry out the same color difference simultaneous transmission, it is found that, unlike the result in the case of FIG. 1, in the case of this embodiment shown in FIG. two signals d
, f have the same color difference signal component (for example, the color difference signal component of the nth horizontal period is Rn-1°Bn), and
No matter how many times the process of converting the signal d into the fifth signal f is repeated, the color difference signal generated in the case of Fig. The disadvantageous result of being delayed one cycle at a time does not occur.

This is clear from comparing Figures 1 and 2.
In the case of Figure 2, the first
The first conversion method from the signal C to the second signal C and the method for converting the third signal d to the fourth signal C shown in FIGS. 2(d) and (e)
This is because the method of the second conversion into the signal e uses the same predetermined method, and as a result, the second
As shown in Figures (C) and (e), the second signal C and the fourth
The signal e has the same color difference signal component in each horizontal synchronization.

In the embodiment shown in FIG. 2 above, when creating a signal for color difference line sequential transmission from a signal for simultaneous color difference transmission,
We have shown an example of a conversion method in which the color difference signal B-Y is assigned to even-numbered horizontal periods and the color-difference signal R-Y is assigned to odd-numbered horizontal periods, but the results shown in Figure 2 can be obtained by , and is not limited to such an example. Instead, a conversion may be performed in which the color difference signal B-Y is assigned to the odd-numbered horizontal period and the color-difference signal R-Y is assigned to the even-numbered horizontal period. , a more different method of conversion may be used.

That is, it is only necessary to satisfy the condition that the signal conversion method from color difference simultaneous transmission to color difference line sequential transmission is always performed using the same predetermined conversion method.

Next, the configuration of a video signal processing circuit for realizing the video signal processing method, which is the second invention of the present application, will be explained.

Figure 3 shows the circuit configuration for the conversion process from the first signal s to the third signal d shown in Figure 2 above. This is a signal processing unit that converts into a signal for color difference line sequential transmission, and in this processing unit 2G, 1 is a video input terminal into which a video signal having a luminance signal and a color signal that is transmitted simultaneously with color difference is input, and 2 is a video input terminal. A decoder circuit (DECODER) 4 decodes the video signal into a luminance signal a and a color difference simultaneous transmission signal (first signal b); Corresponding Fig. 4<g) (h) shows a synchronous separation circuit that outputs signals g and h, and 5 indicates these two signals g.
, h to the control signal I (
The synchronization separation circuit 4 and the switch signal generation circuit 5 constitute a control signal generation means. 3 is a switching circuit for converting the first signal C into a second signal C (
(conversion circuit), which converts the first signal C into a second signal C using the control signal i so that the horizontal period order and the color difference line sequential order have a predetermined relationship. . 6 is a mixing circuit for mixing this second signal C and the luminance signal a. Also, 7 is the transmission line, and this part is recorded.

Reproduction, transmission, processing, etc. are performed.

30, which is opposite to the signal processing section 20, is a color difference line sequencer 4. ．．
Yo Ofl! It's Ifi. . . Kfl*f6@
f□ signal processing section, and in this signal processing section 30,
8 is a separation circuit that separates a video signal including a color difference line sequential transmission signal (second signal C) into a luminance signal a and a second signal C; 9 is a separation circuit that delays the second signal C by one horizontal period; IH
a delay circuit; 10 is a switching circuit that alternately switches the second signal C output from the separation circuit 8 and the IH-delayed second signal to create a third signal d; 11 is a switching circuit for generating a third signal d; An encoder circuit (IINCODER) encodes the signal d and the luminance signal a, and 12 is a video output terminal.・Also, FIG. 5 shows an example of the configuration of the control signal l generation circuit (synchronization separation circuit 4 and switch signal generation circuit 5). In the figure, 25 is an input terminal, 26a, 26
b is a differentiation circuit which detects the edges of the vertical synchronization signal and horizontal synchronization signal respectively taken out by the synchronization separation circuit 4 and obtains signals g and h as shown in FIG. 4; and 27, this signal g is input to the reset (R3T). 28 is an output terminal of a T-flip-flop to which a signal is applied to the clock (T) input.

Next, the operation will be explained.

A video signal including color signals transmitted simultaneously with color difference is input from the video input terminal 1, and this video signal is processed by the decoder circuit 2 into a luminance signal a (corresponding to 181 in FIG. 2) and a color difference signal b (
) in FIG. 2).

Next, a horizontal synchronization signal and a vertical synchronization signal are extracted from the luminance signal a by the synchronization separation circuit 4. Note that these signals may also be extracted from the input video signal.
Then, a signal g corresponding to the vertical synchronization signal and horizontal synchronization signal is generated.

The control signal i (FIG. 4(l)) of the switching circuit 3 is generated from these two signals g and h by the switch signal generating circuit 5.

The color difference signal b (first signal b) obtained by the decoder circuit 2 and transmitted simultaneously is transferred to the second color difference signal sequentially transmitted by the signal switching circuit 3 using the control signal i (FIG. 4 (1)). signal C (FIG. 2(C)).
.

At this time, the color difference signal B-Y is allocated to even-numbered horizontal periods, and the color-difference signal RY is allocated to odd-numbered horizontal periods.

The luminance signal a and color difference signal (second signal C) thus obtained are frequency-multiplexed or time-multiplexed and outputted by the mixing circuit 6, and are recorded, reproduced, transmitted, processed, etc. through the transmission line 7. It will be done.

Next, the signal that has passed through the transmission line 7 (a video signal including a color signal of color difference line sequential transmission) is separated into a luminance signal and a color difference signal by a separation circuit 8, and the luminance signal is input to an encoder circuit 11, which will be described later. It is encoded into a video signal together with the color difference signal d, and is output from the video output terminal 12.

On the other hand, regarding the color difference signal, the signal that has passed through the transmission line 7 is input to the separation circuit 8, whereby a second signal C of color difference line sequential transmission is obtained. Then, this second signal C and this second signal C are processed by the IH delay circuit 9 for one horizontal period (I
H) The delayed signal is alternately switched using the switching circuit 10, and the color 1 and the 3rd signal of the difference transmission are
Create a signal d. This third signal d is input to the encoder circuit 11 together with the luminance signal mentioned above, and is encoded into a video signal (corresponding to the third signal in FIG. 2(d), which is modulated with a single color subcarrier). be done.

The process of converting from the first signal s to the third signal d has been described above. Next, the process of converting from the third signal d to the fifth signal f will be described.

A signal corresponding to the third signal d output from the video output terminal 12 is input to the video input terminal 1, and this video input signal is processed by the decoder circuit 2 into a luminance signal a and a color difference signal d.
It is decoded as

Next, a horizontal synchronization signal and a vertical synchronization signal are extracted from the luminance signal a (or the input video signal) by a synchronization separation circuit 4. From this vertical synchronization signal and horizontal synchronization signal,
Signals g corresponding to these.

h (FIG. 4(g) (hl)) is created, and the switch signal generating circuit 5 creates a signal l (FIG. 4(1)) for controlling the switching circuit 3 from these two signals g and h.

The color difference signal d (third signal d) obtained by the decoder circuit 2 and transmitted simultaneously is sent to the switching circuit.
・・Same as the method of converting the first signal S to the second signal C using the control signal i (Fig. 4 (1)) by path 3, R-Y
is assigned.

The luminance signal a and the color difference signal (fourth signal (e)) thus obtained are frequency-multiplexed or time-multiplexed and outputted by the mixing circuit 6, and are subjected to recording, reproduction, transmission processing, etc. through the transmission line 7. will be carried out.

Next, the signal that has passed through the transmission line 7 is separated into a luminance signal and a color difference signal by a separation circuit 8, and the luminance signal is input to an encoder circuit 11, where it is encoded into a video signal together with a color difference signal f, which will be described later, and is sent to a video output terminal. It is output from 12.

On the other hand, regarding the color difference signal, the signal that has passed through the transmission path 7 is input to the separation circuit 8, thereby obtaining the fourth signal e of the color difference line sequential transmission. Then, this fourth signal e and this fourth signal 6 are processed by an IH delay circuit 9 for one horizontal period (I
H) The delayed signal is alternately switched using the switching circuit 10 to create a fifth signal f for color difference simultaneous transmission.

This fifth signal x4r is input to the encoder circuit 11 together with the previously mentioned luminance signal, and the video signal (FIG. 2(f)
(modulated on the color subcarrier).

The process of converting from the third signal d to the fifth signal f has been explained above, but if further conversion is performed below, the process of converting from the third signal d to the fifth signal f will be explained. Kudzu repeated.

Next, the operation of the control signal i generation circuit will be explained with reference to FIG.

A luminance signal a is input from an input terminal 25, and a synchronization separation circuit 4 separates a vertical synchronization signal and a horizontal synchronization signal. The left edge of each signal is detected by the differentiating circuits 26a and 26b, and signals g and h as shown in FIGS. 4(g) and 4(h) are obtained at each output. This signal g is input to the reset (R3T) input of the T-flip-flop 27, and the signal g is input to the clock (T) input. Then, a control signal i as shown at +11 in FIG. 4 is obtained from the Q output of the T-flimp frond 27.

In this embodiment, when converting a color signal of color difference simultaneous transmission to a color difference line sequential signal, the conversion is always carried out so that the order of the horizontal period and the order of color difference line sequential are in a constant relationship. Therefore, color shift will not occur even when conversion is repeatedly performed between the above two signals during repeated recording and playback. Further, in order to obtain the circuit number of this embodiment, it is sufficient to simply add a simple circuit to the conventional circuit, and the cost does not increase.

In the above embodiment, the circuit for generating the control signal l has a simple circuit configuration as shown in FIG. 5, but the circuit is not limited to this. For example, instead of a T-flip-flop, a more stable A multifunctional counter circuit or the like may be used.

〔Effect of the invention〕

As described above, according to the present invention, signals for simultaneous color difference transmission and sequential color difference line transmission can be transmitted.
When converting between the color signals of the color difference simultaneous transmission and the color difference line sequential transmission, the color signals of the color difference line sequential transmission are converted into the color signals of the color difference line sequential transmission using a conversion method that always maintains a constant relationship between the horizontal period order and the color difference line sequential order. Since it is converted into a signal, it is possible to prevent delays in the color difference signal even when conversion is repeatedly performed between the above two signals, and furthermore, the processing circuit to realize this can be simply added by simply adding a circuit. There is an effect that can be achieved with

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship of signal placement when video signal processing is performed using a conventional method, and FIG. 2 is a diagram showing the relationship of signal placement when signal processing is performed using a video signal processing method according to an embodiment of the present invention. 3 is a block diagram of the same path for video signal processing according to an embodiment of the present invention, FIG. 4 (al is a signal arrangement diagram showing the order of luminance signals, and FIG. 4 (gl (h)
4(1) is a waveform diagram of a signal output from the switching signal ordering circuit of the circuit shown in FIG. 3, and FIG. 5 is a waveform diagram of a signal output from the synchronous separation circuit of the circuit shown in FIG. 3, respectively. The figure is a diagram showing an example of the configuration of a portion related to control signal generation in the circuit shown in FIG. 3. 2... Decoder circuit, 3... Switching circuit (conversion circuit), 4-... Synchronous separation circuit, 5... Switch signal generation circuit, 6... Mixing circuit. , Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) For a video signal in which a luminance signal and a chromaticity signal are time-axis multiplexed or frequency multiplexed, the color signal for simultaneous color difference transmission is horizontally transmitted in order to perform color difference simultaneous transmission with all color information in each horizontal period. Converts, records, and transmits color signals into color signals for color difference line sequential transmission for carrying out color difference line sequential transmission with color difference signals divided into a plurality of horizontal periods so that the order of cycles and color difference line sequential order have a predetermined relationship. The color signal for color difference line sequential transmission that has undergone the above processing is converted into a color signal for color difference simultaneous transmission using color information of a plurality of temporally or spatially adjacent horizontal periods, and hereinafter referred to as the color signal for color difference simultaneous transmission. 1. A video signal processing method characterized in that when converting a color signal into a color signal for color difference line sequential transmission, the conversion between the two is performed while maintaining the above predetermined relationship. (2) The above-mentioned predetermined relationship when converting the color signal for color difference simultaneous transmission into the color signal for color difference line sequential transmission is based on the even or odd horizontal period calculated from the vertical synchronization signal of the video signal or a signal equivalent thereto. The R-Y signal of the color difference signals is
The video signal according to claim 1, wherein the video signal has such a relationship that the sequential order of the color difference lines is determined by assigning the B-Y signal of the color difference signals in odd or even horizontal periods. Processing method. (3) For a video signal in which a luminance signal and a chromaticity signal are time-axis multiplexed or frequency multiplexed, a color signal for simultaneous color difference transmission and multiple color signals for simultaneous color difference transmission having all color information for each horizontal period are used. In a video signal processing circuit that performs conversion between color signals for color difference line sequential transmission for performing color difference line sequential transmission having color difference signals divided into horizontal periods of a decoder circuit that decodes the input video signal into a luminance signal and a color signal for simultaneous color difference transmission; and a control signal generator that generates a control signal for conversion processing based on a vertical synchronization signal and a horizontal synchronization signal included in the video signal. means for converting the color signal for color difference simultaneous transmission outputted from the decoder circuit into a color signal for color difference line sequential transmission such that the horizontal period order and the color difference line sequential order have a predetermined relationship according to the conversion processing control signal. and a mixing circuit that mixes the color signal for color difference line sequential transmission with the luminance signal output from the decoder circuit, and outputs a video signal including the color signal for color difference line sequential transmission. A video signal processing circuit characterized by: