JPS60198988A - Recording and reproducing method of color difference signal - Google Patents

Abstract

PURPOSE:To record and reproduce an excellent video signal by applying line sequencing to the 1st and 2nd color difference signals on the same line in a color video signal, synchronizing the line sequential signal reproduced at reproduction and interpolating a missing line with an average value of the color difference signal so as to prevent generation of hue change. CONSTITUTION:A V signal at an input terminal 33 is fed to a switch 36 and a U signal at an input terminal 34 is subject to 1H delay 35 and fed to the other terminal of the switch 36 at recording in the recording/reproducing signal system of a color difference signal, the switch 36 is changed over at each horizontal scanning and a line sequential signal is outputted to an output terminal 38. Further, the line sequential signal from an input terminal 39 is fed to a switch 40 at reproduction, the switch 40 is switched at each horizontal scanning and the line sequential signal is separated into the U and V signals. The V signal is fed to one terminal of a switch 45, and the V signal subject to 1H delay 43 is applied to the other terminal of the switch 45. Further, the U signal is fed to one terminal of a switch 46, the U signal subject to 1H delay 44 is fed to the other terminal, the switches 45, 46 are switched at the same time at each horizontal scanning and the U and V signals are outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color difference signal processing method used in a color video signal recording/reproducing device, such as a video tape recorder, when the color difference signals are recorded and reproduced line-sequentially. be.

Conventional configurations and problems There are known methods for recording color accuracy in a rotating two-head video tape recorder, such as those that use quadrature two-phase modulation signals of color difference signals, and those that use line-sequential color difference signals. It is being An example of a video tape recorder using line-sequential color difference signals is one in which the line-sequential color difference signal and the luminance signal are each time-compressed, time-divisionally synthesized within one horizontal scanning time, and this combined signal is used as a recording signal. There is. This configuration is shown in FIGS. 1 and 2.

Figure 1 shows the configuration during recording, where 1 is the input terminal for the composite video signal, 2-digit low-pass filter, 3 is the time compression circuit, 4 is the bandpass filter, and 5 is the input terminal for the carrier color signal (R-Y ).

A color decoder detects two color difference signals J8' (B-Y), 6 is a line conditioning circuit, 7 is a time compression circuit, 8 is a synthesis circuit, 9 is an FM modulator, and 10 is a recording magnetic head.

A composite video signal inputted from the input terminal 1 in FIG. 1 is supplied to a low-pass filter 2, where the luminance signal is separated. The luminance signal is supplied to the time compression circuit 3 and is time compressed to a predetermined ratio. On the other hand, the carrier color signal in the input composite video signal is extracted by the bandpass filter 4 and supplied to the color decoder 5.

The color decoder 5 converts the carried color signal into a (R-Y) color difference signal (hereinafter simply referred to as the V signal) and a (B-Y) color difference signal (
Hereinafter, it will simply be referred to as the U signal. ) is detected.

The detected U signal and V signal are supplied to the line conditioning circuit 6,
This becomes a line-sequential color difference signal. And the line sequential color difference θ is 11.
The signal is supplied to a compression circuit for 5 hours, compressed for 1 hour, and combined with a time-compressed luminance signal in a synthesis circuit 8. Therefore, the output of the synthesis circuit 8 is a time compressed video signal of 1υ. Figure 3 shows the waveforms of each part of A to D in Figure 1 in the case where the composite video signal is a color par signal, and the line sequential conversion is simply switching between the U signal and the ■ signal every horizontal scan. . The time-compressed luminance signal period T3 shown in D in FIG. 3 is T of the luminance signal A.
This is one period compressed in time. Also, the period T41tl1 of the time compression circuit signal 5D is the time period compressed from the T2 period of the U signal 9C. The T5 period of the time-compressed video signal is the insertion period of an index signal provided to detect whether the color difference signal is a U signal or a V signal during reproduction.0 The output signal of the combining circuit 8 in FIG. The signal is FM modulated and recorded on the tape via the magnetic head 10.

FIG. 2 shows a configuration for reproducing a composite video signal from a time-compressed video signal recorded using the configuration shown in FIG.

11 is a reproduction magnetic head, 12 is a switch, 13 is an amplifier, 14 is an FM demodulator, 16 and 16 are time expansion circuits, 1
7 is a synchronization circuit that obtains continuous U and V signals from line sequential signals, 18 is an encoder that forms a carrier color signal from the U and V signals, 19 is a mixing circuit, and 20 is a composite video signal output terminal. A time-compressed video signal, which is an FM modulated signal detected by the magnetic head 11, is turned into a continuous signal by a switch 12, amplified by an amplifier 13, and supplied to an FM demodulator 14. Therefore, the FM demodulator 14 outputs the time compressed video signal shown in the third diagram. The luminance signal portion in the time-compressed video signal is time-expanded by a time expansion circuit 15 and returned to its original state. Further, the color difference signal in the time-compressed video signal is time-expanded and returned to the original line-sequential color difference signal. The output signal of the time expansion circuit 16 is supplied to the synchronization circuit 17, where it is separated into a U signal and a V signal, and output as a continuous signal. The output signal of the synchronization circuit 17 is sent to the encoder 1
8, the signal is converted into a predetermined carrier color signal, and mixed with a luminance signal in a mixer 19.

Therefore, a composite video signal is reproduced at the terminal 20.The configuration of a generally well-known line sequential and synchronization system based on color difference used when recording and reproducing video signals in this manner is described below. Shown in Figure 4.

In FIG. 4, 21F'iv signal input terminal, 22(d
There is a U signal input terminal, 23ij switch, 24 is a control signal for switch 23, and switch 23 is switched every horizontal scan. This is an output terminal for a 25-wire sequential signal.

Therefore, the signals of each part of the line 11th-order circuit 8Fi are as shown in FIG. 5. n-2, n, , n- in FIG. Representing the U signal in the horizontal line, V 2.V , , Vo
・ ・represents the V signal on each horizontal line. Therefore, the line sequential signal outputted to the terminal 25 is a signal in which the U signal and the V signal are switched for each line. Next, the synchronization circuit will be explained. In FIG. 4, 26 is an input terminal for a line sequential signal, a delay line having a delay time of 27 digits 1 horizontal scanning time, 28, 29 is a switch, 30 is a switch 2, and a control signal for 29, 1 horizontal scanning 4 ■ Switch to. 31 is an output terminal for the ■ signal, and 32 is an output terminal for H and U signals. FIG. 5 shows the signals of each part of this synchronization circuit. Switches 28 and 29 are switched every horizontal scan by control signal U30, and the input signal from terminal 26 outputs a delayed signal, so that the missing line is interpolated with the signal from one line before at terminals 31 and 32. A V signal and a U signal are output.

The conventional recording and reproducing method using line sequential signals as described above with reference to FIGS. 4 and 5 has a problem in reproduced image quality. Since this is a line sequential signal, the signal of the missing line is interpolated with the signal of the previous line, so if there is no correlation between the color signals between the two lines, the color level and hue will be significantly different from the input signal, resulting in an unnatural image. It is what happens.

The case where there is no line correlation will be explained using FIG. 6.

Figure 6 shows the levels of the U signal and V signal during recording, respectively.
1" or "Q" to represent a step response assuming a state in which there is color in the vertical direction on the screen to a state in which there is no color. When the U and V signals change from "1" to ro on the nth line of the input signal, the color difference signal in one direction of the playback output becomes "1" on the nth line, and the other becomes "o", and the reproduction A color signal exists on the nth line on the screen, and the hue changes significantly.

As described above, the conventional method has a problem in that the hue changes when there is no line correlation.

OBJECTS OF THE INVENTION The present invention solves the problems in recording and reproducing color-difference images using the conventional method, and particularly solves the problems in recording and reproducing color-difference images using the conventional method.
The overall object of the present invention is to provide a method for recording and reproducing color difference signals in which no hue change occurs.

Structure of the Invention The present invention converts the first and second color difference signals of the same line of a color video signal into line sequential signals during recording, uses this line sequential signal as a recording signal, and generates an fJG signal during playback. This is a color difference recording and reproducing method in which line-sequential signals are synchronized and missing lines are interpolated with the color difference signal of the immediately preceding or succeeding line and the average signal of the color difference signals of the lines before and after. However, no hue change occurs.〇Description of Examples The present invention will be explained below using Examples.

FIG. 7 shows a line sequential circuit and a simultaneous circuit for color difference signals in one embodiment of the present invention. In FIG. 7, 33 is an input terminal for a V signal, 34 is an input terminal for a U signal, 35 is a 1H delay line, 36 is a switch, 37 is a control signal input terminal, 38 is an output terminal for a line sequential signal during recording, 39 is an input terminal for line sequential signals during playback, 40 is a switch, and 41 is a switch 40
control terminal, 42.43.44 is 1H delay line, 46.4
6 is a switch, 4 is a control terminal for switches 45 and 46,
48 is an output terminal for the V signal, and 49 is an output terminal for the U signal.

In FIG. 7, during recording, the switch 36 switches and outputs the V signal and the delayed U signal every horizontal scan.

Therefore, the line-sequential signal that is output is a line-sequential signal obtained by line-sequencing the V signal skipping signal on the same line. During playback, the lines input from the terminal 39 are sent sequentially to the switch 40,
The switch 4° is switched every horizontal scan by a control input from the terminal 41, and separates the line sequential signal into a U signal and a signal. Separated V signal to 1H delay line 4
2 and is supplied to the input terminal of switch 45.

The output signal of the sweet 1H delay line 42 is supplied to the other -☆Hg of the switch 45 via the delay line 43. On the other hand, the U signal separated by the switch 41 is supplied to the input end of the switch 4, and is also supplied to the other end of the switch 46 via the delay line 44. Switches 45 and 46 are control terminals 4
It is switched every horizontal scan by a control signal inputted from 7. Therefore, as shown in FIG. 8, for example, the V signal and U signal outputted to the terminals 48 and 49 are outputted at the same time, and any missing line is interpolated with the signal from one horizontal scan ago.

Regarding the signals of each part in the configuration shown in FIG. 7, depending on the timing of the control signal that controls the switch 36 and the color difference signal, the color difference signal of the nth line may be recorded or the color difference signal of the nth line may not be recorded. . Figure 8 shows the case where the color difference signal of the nth line is recorded, and Figure 1Q shows the case where the color difference signal of the nth line is recorded.
This is a case where the color difference signal of the number line is not recorded.

Step responses in the configuration shown in FIG. 7, which is an embodiment of the present invention, are shown in FIGS. 9 and 11.

FIG. 9 shows the case where the nth line is recorded, and FIG. 11 shows the case where the nth line is not recorded.

Regardless of whether the n-th line is recorded or the n-th line is not recorded, the color difference signals of the same line are made line-sequential during recording and restored to the original state during playback if they are distorted, so no hue change occurs.

In the configuration shown in FIG. 7, since the reproduced color difference signal is delayed by one or two lines, it is necessary to delay the luminance signal, but this can be easily realized.

As explained above with reference to FIGS. 7 to 11, in this embodiment, the color difference values of the same line are line-sequentially recorded during recording, and are synchronized during playback. No hue change occurs in the signal either.

In the configuration shown in FIG. 7, when the color difference signal changes stepwise, as shown in FIGS. 9 and 11, (n+1
) There may or may not be a love interest on the line. And this means that the number of scanning lines for television is NT.
There are 525 lines for SC and 625 lines for PAL, both of which are odd numbers, so the (n-11)th line may or may not have a color signal in each frame. This causes color flicker to occur at positions on both sides where there is no line correlation.

- Next, another embodiment method will be described which prevents the occurrence of color flicker and improves the color difference signal processing method of the above embodiment.

FIG. 12 shows a circuit used in this second embodiment method, and shows a specific circuit configuration for obtaining the supplied control signal. In FIG. 12, 5o is an input terminal into which the composite video signal to be recorded is input, 51 is a synchronizing signal separation circuit, 52 is a horizontal dome signal separation circuit, 53 is a bar frequency dividing circuit, 64 is an inverter, and 55 is a switch. , 56 is an output terminal, 57 is a vertical synchronizing signal separation circuit, and 58 is an 1A frequency dividing circuit.

The composite video signal is supplied to a separation circuit 51 (19) Mi, where the synchronization signal is separated. The separated synchronization signal Ji3 is supplied to the horizontal synchronization signal separation circuit 52, where the horizontal synchronization signal is separated. The horizontal synchronizing signal is supplied to the frequency dividing circuit 63 and frequency-divided by A, and the output signal of this frequency dividing circuit 63 is outputted to the output terminal 56 either directly or after having its phase inverted by an inverter, and is converted into line sequential data during recording. This becomes the final switch control signal. On the other hand, the output signal of the synchronization separation circuit 51 is supplied to a vertical synchronization signal separation circuit 57, where the vertical synchronization signal is separated.

The separated vertical synchronizing signal is frequency-divided by A in a frequency divider 58 and supplied to a switch 55 as a control signal. 1st
FIG. 13 shows the waveforms of each part of N-Q in FIG. 2, and the signal output to the output 1 aperture 56 has its phase inverted every frame. In this way, by supplying the /fJ signal to the control terminal 37 in FIG. 7 and controlling the line sequential switch 36, even if the frame changes, the line sequential signal will not change to the line sequential signal H or 10 in FIG. Since it is fixed to one of the positions shown in FIG. H, color flicker does not occur.

Next, still another embodiment of the present invention is shown in FIG. 1st
The configuration shown in FIG. 4 is a case where an average of two lines of color difference signals is used when performing line sequentialization during recording, and a case where a missing line is interpolated with the average signal of the preceding and succeeding lines during reproduction. 15 and 17 show the signals of each part in FIG. 14, and unnecessary parts are left blank.

In Fig. 14, 5 is the input terminal of Tsukuda=θ, 60 is the input terminal of U input, 61.62 is 1H delay ￥fJ, 6
3. 4 is a mixer, 65 is a 1H delay line, 66 is a switch, 67 is an input terminal for a control signal that switches the switch 66 every horizontal scan, and 68 is an output terminal for a line sequential signal during recording. 69 is an input terminal for line sequential signals during playback; 7
o is a switch, 71 is an input terminal for a control signal that switches the switch 70 every horizontal scan, 72, 73, 74, 76 .
76 is a 1H delay line, 7 and 78 are mixers, 7e and 8o are switches, 81 is an input terminal for a control signal that switches switches 79 and 8o every horizontal scan, 82 is a V signal output terminal, and 83 is a This is the output terminal for the U signal.

In the configuration of FIG. 14, the 1H delay line 61 and the mixer 63
The 1H delay line 62 and mixer e4 each constitute a comb filter. Therefore, the V signal and the U signal are averaged over two lines by the comb filter, resulting in signals represented by R and S. After passing through the comb filter, the signal is further supplied to a switch 66 via a 1H delay line 65. Therefore, the line sequential signal outputted to the output terminal 68 is the first line sequential signal.
The U signal and V signal at the same time represented by T in FIG. 5 or FIG. 17 are line-sequentialized.

During reproduction, this line sequential signal is input to the terminal 69. The switch 70 separates the U signal and V signal, and the ■ signal is 1.
The output signal j;
It is supplied to the other end of the switch 79 via a comb filter composed of a mixer 77 and a mixer 77 . The fcU signal separated by switch 70 is supplied to one end of switch 8° via a 1H delay line 74, and to the other end of switch 80 via a comb filter consisting of delay lines 74 and 76 and a mixer 78. supplied to Switches 79 and 80 are switched in synchronization with one horizontal scan D by a control signal applied from a control signal input terminal 81, and the V signal outputs a comb filter output signal to a terminal 82. is U
The signal also operates to output the output of the comb filter to the terminal 83. Therefore, when recording, the average of the color difference signals of the (n-1)th line and the nth line is line-sequentially recorded, and the color difference signals of the nth line and (n-1-1)th line are line-sequentially recorded. Although there will be slight deviations depending on whether the signal is recorded in the same way, the signal of each part will be as shown in Figure 15 or Figure 17, and the reproduced output color difference signal will be the average signal of the two lines, and the missing line will be the average signal of the lines before and after it. This is the interpolated signal.

Step responses in this case are shown in FIGS. 16 and 18.

Step response [(n+1)th line is %.

There are cases where the (n+2)th line is W and the (n+3)th line is %, and only the (n+2)th line is at the color difference signal level of 14, but the U signal and ■ signal also change in the same way. Therefore, no hue change occurs.

However, if each frame is K as shown in Fig. 16, and
As shown in the figure, color flicker occurs on the screen. In this case as well, color flicker can be removed by inverting the control signal at the terminal 67 for each frame using the configuration shown in FIG. 12, for example.

Detailed Description of the Invention As described above, the present invention converts U and V signals of the same line into line-sequential signals during line-sequentialization, and when restoring color difference signals from this line-sequential signal, The same line extension signal and V signal are obtained. This has the effect that no hue change occurs even in video signals without line correlation.

Further, the occurrence of color flicker can be prevented by inverting the control signal of the switch used for line sequentialization in any one frame in the configuration shown in FIG. 6, for example.

Furthermore, when interpolating a missing line during playback, even if the signal immediately before the missing line is interpolated, or the average signal of the lines before and after it is interpolated, the hue of the video signal with no lie/correlation will not change. It is something.

Therefore, for example, the color difference borrowing processing method of the present invention is
When applied to the video tape recorder shown in FIG. 2 and FIG. 2, a good bidirectional image can be obtained even when the color difference signals are converted line-by-line and recorded and reproduced.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams of the video signal processing unit of a rotary two-head video chip/recorder during recording and playback, respectively, and FIG. 3 is an explanation of the operation of the video signal processing unit. FIG. 4 is a configuration diagram of a conventional color difference signal processing method, FIG. 6 is an explanatory diagram of its operation, and FIG. 12 is a block diagram showing an example of a configuration for preventing color flicker in the embodiment of FIG. 7, and FIG. 13 is a diagram showing the signals of each part in FIG. 12. A waveform diagram, FIG. 14 is a configuration diagram of another embodiment of the present invention, and FIGS. 16 to 18 are diagrams explaining its operation. 33.59 ~ ■ Signal input terminal, 34.60...U signal input terminal, 35.42.43.44.61°62.6
6.72,73,74,75,761H delay line, 36,
40,46,46,66°0,79.80-...Switch, 48.82--V signal output terminal, 49.83-
・U signal output terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Fig. 3 Fig. 4 Drop Fig. 5 Fig. 7 R1 Fig. 8 Fig. 9 Fig. 1 01; sf Fig. 11 Fig. 1 Fig. 12 Fig. 13 Fig. 15

Claims (2)

[Claims] (1) At the time of recording, the first and second color difference signals forming the same line with a color video signal are line-sequentialized, this line-sequential signal is used as a recording signal, and at the time of playback, the reproduced line-sequential signal is A color difference signal recording and reproducing apparatus characterized in that the missing line is synchronized and interpolated with the color difference signal of the line immediately before or after the missing line, or the average signal of the color difference signals of the lines before and after the missing line. (2) The color difference signal recording and reproducing method according to claim 1, wherein the color difference signal to be line-sequentialized is always a color difference signal of the same line in each frame.