JPH043716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a color image signal synthesis method for synthesizing two color image signals to obtain a new composite color image signal.

(Prior Art) Conventionally, as a simple method for synthesizing two color image signals, a method has been used in which color image signals in the form of television signals are directly mixed.

Figure 1 shows a rotating head type magnetic recording and reproducing device (hereinafter referred to as VTR) that can obtain a composite color image signal using such a conventional composition method and record it.
FIG. 1 is a magnetic tape, and 2 is a cylindrical tape guide drum on which the tape 1 is wound approximately 180 degrees diagonally. 3 is a supply reel for the magnetic tape 1, and 4 is a take-up reel. The magnetic tape 1 runs in the direction of arrow 5, and the drum 2 rotates in the direction of arrow 6. Heads 7 and 7' are used during normal recording and reproduction, and heads 8 and 8' are used to record composite color image signals.

During normal recording, the color image signal input from the input terminal 10 is supplied to the recording signal processing circuit 12 via the changeover switch 11, and after being converted into a signal form suitable for magnetic recording by the recording signal processing circuit 12, the changeover switch 13 is turned on. The data are recorded on the magnetic tape 1 by the heads 7, 7' via the magnetic tape 1. At this time, switch 11 and switch 13 are each connected to the R side in the figure.

During normal playback, switch 13 and switch 15 are each connected to the P side in the figure. The reproduced color image signal reproduced by the heads 7 and 7' is supplied to the reproduced signal processing circuit 14 via the switch 13 and returned to the television signal.
It is output from terminal 16 via.

FIG. 2 is a diagram showing the state on the magnetic tape 1 recorded by the VTR shown in FIG. 1. 19A, 19
B, 19C, and 19D are tracks on which one field of color image signals are each recorded.If track 19A is recorded in head 7, track 19B is recorded in head 7', and track 19C is recorded in head 7. If the head 7 is now in the position shown in FIG. 2 and tracing the track 19C, the head 8 is arranged so as to trace the same part of the adjacent track 19D. Head 7'
The arrangement of the head 8' and the head 8' is also similar.

Next, the operation when recording a composite color image signal using the heads 8 and 8' will be explained. In this case, the switch 13 is connected to the P side in the figure, and the switch 11 and the switch 15 are each connected to the M side in the figure. The color image signal reproduced by the heads 7 and 7' is returned to a television signal by the reproduced signal processing circuit 14, and is supplied to the mixer 17 via the switch 15, where it is mixed with a new television signal input from the terminal 10. be done. At this time, the rotation servo of the drum 2 is performed using a vertical synchronization signal separated from the new television signal inputted from the terminal 10. Therefore, the timings of the reproduced color television signal and the new television signal are made to match. The composite color image signal obtained by the mixer 7 is converted into a signal form suitable for magnetic recording again by the recording signal processing circuit 18, and is then converted into a signal form suitable for magnetic recording by the heads 8, 8', on the track next to the track being traced by the heads 7, 7'. Yes, the data is recorded on the track that has already been played back by the heads 7, 7'.

However, when color image signals are synthesized using this method, there arise problems such as moiré of the color signals and changes in hue. That is, in the case of multiplexing, it is difficult to completely match the phases of one color signal and the other color signal. Moreover, by multiplexing both color signals, they influence each other and cause a phase shift, that is, a hue shift.

Therefore, conventionally, in television broadcasting, etc., a method has been used to synthesize two color image signals by switching and outputting the two color image signals according to the luminance signal level and the phase (hue) of the color signal of one color image signal. There is.

However, for example, when creating a switching signal according to the luminance signal level, a high luminance (white) or low luminance (black) background must be placed on the portion of one color image signal that is not desired to be combined. This can be achieved by shining a spotlight on the subject you want to photograph or by photographing a white wall in the background.
The shooting itself turned into a very large-scale project.

Furthermore, since the image signals are switched, the image signals that are discarded due to this switching are not reflected in the composite image signal at all. Therefore, the effect of duplicating two types of screens cannot be expected.

Furthermore, if the color image signal used to create the switching signal is close to the threshold value, there will be too many switching parts in one screen, making the screen very unsightly. Put it away.

(Objective) In view of the above-mentioned drawbacks, the present invention provides a color image that can obtain a good composite image signal without any unsightly appearance due to hue shift or switching without any special efforts when photographing color image signals to be composited. The purpose is to present a signal synthesis method.

(Example) FIG. 3 is a diagram showing an example in which the synthesis method of the present invention is applied to a VTR.

21 and 22 are recording heads, 23 and 24 are reproduction heads, and the heads 21, 22, 23, 24
are fixed to the rotating drum 25, respectively. FIG. 4 is a diagram showing the state on the magnetic tape 1 recorded by the VTR shown in FIG. 3. 26A, 26B,
Tracks 26C and 26D each record one field of color image signals, and are recorded in the order of tracks 26A, 26B, 26C, and 26D by the recording heads 21 and 22. 27 is an arrow indicating the direction in which the magnetic tape 1 travels.

Assuming that the recording head 21 is now in the position shown in FIG.
is located at the position shown and traces the same track 26B. When the head 21 finishes recording one field's worth of color image signals on the track 26B, the heads 22 and 24 then trace the track 26C. head 22 and head 24
The azimuth angles of the heads 21 and 23 are the same, and the azimuth angles of the heads 21 and 23 are different. The positional relationship between the heads 22 and 24 is almost the same as the positional relationship between the heads 21 and 23 shown in FIG.

In this configuration, the operation during normal recording will first be explained. In FIG. 3, 28 is a terminal to which a color television signal is input, and in this embodiment, the input color image signal will be described as an NTSC signal. The NTSC signal input from the terminal 28 is passed through a high-pass filter (hereinafter referred to as HPF) 29 for separating the carrier color signal and a low-pass filter (hereinafter referred to as LPF) for separating the luminance signal.
30.

The luminance signal separated by LPF30 is sent to switch 3.
The signal is supplied to a frequency modulator (hereinafter referred to as FM modulator) 32 through the N terminal of 1, and is subjected to FM modulation. The FM modulated luminance signal is sent to the mixer 3 via the amplifier circuit 33.
4. Furthermore, the luminance signal separated by the LPF 30 is supplied to a synchronization separation circuit 35, where the synchronization signal is separated. Furthermore, the horizontal synchronization signal is sent to the horizontal synchronization separation circuit 36 from the synchronization signal, and the horizontal synchronization signal is sent to the vertical synchronization separation circuit 3.
At 7, the vertical synchronization signals are separated.

On the other hand, the carrier color signal separated by the HPF 29 is supplied to the L-side terminal of the switch 39 via the A-side terminal of the switch 38, and the signal whose phase is inverted by the phase inversion circuit 40 is supplied to the H-side terminal of the switch 39.
The switch 39 is configured so that the phase of the color signal is shifted by 180 degrees every horizontal scanning period (hereinafter referred to as 1H) between adjacent tracks recorded on the magnetic tape 1. This is a switch for switching between and passing the carrier color signal. For example, in odd fields, it is always connected to the L side terminal, and in even fields,
The H side terminal and the L side terminal are connected alternately every 1H. This is a process performed during recording using the known PI method.
The switching of this switch 39 is performed by a switching signal generation circuit 41.
controlled by The switching signal generation circuit 41 is separated by a horizontal synchronization separation circuit 36 and has an N signal of a switch 42.
A horizontal synchronization signal via a side terminal and a vertical synchronization signal separated by a vertical synchronization separation circuit 37 are supplied.

The carrier color signal processed in this manner is frequency-converted by a frequency converter 43 to a band lower than the band of the above-mentioned FM modulated luminance signal, and is supplied to a mixer 34 via an amplifier circuit 44. In the mixer 34
The FM modulated luminance signal and the low frequency converted color signal are mixed to obtain a mixed signal. This mixed signal is recorded as a color image signal on the magnetic tape by the recording heads 21 and 22 via the N-side terminal of the switch 45 and the head switching circuit 46. Although not shown, the head switching circuit 46 is controlled by a vertical synchronization signal separated from the input color image signal. That is, it is controlled by a vertical synchronization signal separated by a vertical synchronization separation circuit 37 in the figure.

Here, the control of the rotating head during normal recording,
That is, the control of the drum 25 will be explained. The vertical synchronization signal separated by the vertical synchronization separation circuit 37 is supplied to the phase comparison circuit 49 via the R side terminal of the switch 48. On the other hand, 50 is a magnet for generating phase detection pulses (hereinafter referred to as PG), 51 is a PG head, and the PG pulse obtained from the PG head 51 is sent to the phase comparator circuit 4 through the R side terminal of the switch 52.
9. The phase error output between the vertical synchronization signal and the PG pulse obtained by the phase comparator circuit 49 is supplied to the control signal addition circuit 54 via the N-side terminal of the switch 53, and the phase error output is obtained by the speed control circuit 55 based on the PG pulse. Added to speed control signal. The drum motor rotation control signal obtained by the control signal addition circuit 54 is then supplied to the drum motor drive circuit 56 to control and drive the drum motor, and the vertical synchronization signal is applied to predetermined positions of the tracks 26A to 26D shown in FIG. Drum 4 while controlling the phase so that it is recorded.
7 rotates at a constant speed of 60 revolutions per second. 57 is an arrow indicating the rotation direction of the drum 25.

The capstan motor 59 that drives the capstan 58 obtains a speed control signal in a speed control circuit 61 based on an FG signal obtained from a signal generator 60 for detecting rotation of the capstan motor 59 (hereinafter referred to as FG). The rotation speed is controlled to be constant by driving the capstan motor drive circuit 62 using the speed control signal.

On the other hand, the vertical synchronization signal separated by the vertical synchronization signal separation circuit 37 is recorded on the end of the magnetic tape 1 by the control head 64 as a control signal via the R side terminal of the switch 63.

Next, the operation during normal playback will be explained. In this case, switches 48, 52, and 63 are each connected to the P side terminal. The reproduced signals reproduced by the reproduction heads 23 and 24 are supplied to a preamplifier 66 via a head switching circuit 65. From the reproduced color image signal amplified by the preamplifier 41, the HPF 67 separates the FM modulated luminance signal and the LPF 68 separates the low frequency conversion color signal. FM modulated luminance signal is
The signal is FM demodulated by an FM demodulator 69 to produce a luminance signal in the form of an original television signal.

The reproduced luminance signal thus formed into a television signal is passed through an amplifier circuit 70 to a mixer 7.
1. On the other hand, since the low-frequency conversion color signal has been processed so that the phase is shifted by 180 degrees every 1H between adjacent tracks, it is necessary to return it to the original phase. The switch 72 is a switch that selectively outputs the signal that has passed through the phase inversion circuit 73 from the H side terminal and the signal that has not passed through the phase inversion circuit 73 from the L side terminal. For example, if odd fields are recorded with a constant phase and even fields are recorded with phase inversion every 1H, the playback signal of the odd field is always taken out from the L side terminal, and the playback signal of the even field is Take out the L side terminal and H side terminal alternately every 1H. The switching of this switch 72 is controlled by a switching signal generating circuit 74. The switching signal generation circuit 74 includes a synchronization separation circuit 75, a horizontal synchronization separation circuit 76, and a switch C of a switch 77 based on the reproduced luminance signal.
A horizontal synchronizing signal obtained through a side terminal and a vertical synchronizing signal obtained via a synchronization separation circuit 75 and a vertical synchronization separation circuit 78 are supplied.

The low band converted color signal passed through the switch 72 is frequency converted to the original band by a frequency converter 79. The frequency-converted color signal is processed using a 1H delay line (hereinafter referred to as 1HDL).
(referred to as ) 80 and is added with an adder 81 to remove color signal crosstalk from adjacent tracks. The switch 82 is connected to the C side terminal during normal reproduction. The reproduced color signal from which crosstalk has been removed by the adder 81 is supplied to the mixer 71 via the amplifier circuit 83 and multiplexed with the reproduced luminance signal. The reproduced color television signal obtained by mixer 71 is output from terminal 84 to the outside. The head switching circuit 65 mentioned above is controlled by the reproduced vertical synchronization signal separated by the vertical synchronization separation circuit 78.

During normal playback, the reproduced vertical synchronization signal separated by the vertical synchronization separation circuit 78 is sent to P of the switch 48.
The signal is supplied to the phase comparison circuit 49 via the side terminal, and is compared in phase with the output reference signal of the reference oscillator 85 via the P side terminal of the switch 52. The phase control signal obtained by the phase comparator circuit 49 is added to the speed control signal in the control signal addition circuit 54 as in normal recording. The rotation of the drum 25 is controlled via a drum motor drive circuit 56.

Next, control of the capstan 58 will be explained. First, a speed control signal obtained by the speed control circuit 61 based on the FG signal obtained in the same manner as during recording is supplied to the control signal addition circuit 86. The control head 64 reproduces the control signal recorded on the edge of the magnetic tape 1 during normal recording, and supplies this reproduction control signal to the phase comparator circuit 87 via the P-side terminal of the switch 63. In the phase comparison circuit 87, the vertical synchronization signal separated from the reproduction luminance signal by the vertical synchronization signal separation circuit 78 and the reproduction control signal are phase-compared. Phase comparison circuit 8
The output of 7 is supplied as a phase control signal to a control signal addition circuit 86, where the speed control signal is added to the control signal addition circuit 86.
The capstan motor drive circuit 62 is controlled by the output.

The operation of recording a composite color image signal in the VTR shown in FIG. 3 will be described below. At this time, switches 31, 42, 45, and 53 are each connected to the M side terminal.

The color image signals reproduced by the reproduction heads 23 and 24 are supplied to the aforementioned reproduction signal processing circuit via a head switching circuit 65, and a reproduced color television signal is obtained by a mixer 71. The control of the head switching circuit 65 at this time is performed by the vertical synchronizing signal separated by the vertical synchronizing signal separation circuit 78, as in normal reproduction. The reproduced color signal obtained by the adder 81 is supplied to the B side terminal of the switch 38, and the reproduced luminance signal obtained by the FM demodulator 69 is supplied to the adder 87.

Meanwhile, a new color television signal is being supplied to terminal 28. The carrier color signal separated from this signal by the HPF 29 is supplied to the A side terminal of the switch 38, and the luminance signal separated by the LPF 30 is supplied to the adder 87. The adder 87 adds the reproduced luminance signal and the new input luminance signal to obtain a composite luminance signal, which is supplied to the mixer 34 via the M side terminal of the switch 31, the FM modulator 32, and the amplifier circuit 33. Ru. The switch 38 is switched between the A side terminal and the B side terminal every 1H by the switching signal generating circuit 88. Switching signal generation circuit 88
A horizontal synchronization signal separated by a horizontal synchronization separation circuit 36 is supplied to the horizontal synchronization signal. As a result, a composite color signal is obtained from the switch 38 in which the reproduced color signal and the newly input carrier color signal are alternately taken out every 1H.

This composite color signal is processed to remove crosstalk between adjacent tracks as described above, but in this case, since correlated signals are repeated every 2H, the composite color signal is processed every 2H. The phase must be shifted by 180°. That is, for example, in several fields, the switch 39 is always L.
connected to the side terminal, and in even fields
The H side terminal and the L side terminal are connected alternately every 2H. Therefore, the number of horizontal synchronizing signals input to the switching signal generating circuit 41 must be halved, and the horizontal synchronizing signal passed through the 1/2 down converter 89 is obtained via the M side terminal of the switch 42.

The synthesized color signal processed in this manner is again frequency-converted to a low frequency by the frequency converter 43, and is supplied to the mixer 34 via the amplifier circuit 44. Then, the composite color signal and the composite luminance signal are multiplexed in a mixer 34 to obtain a composite color image signal. The composite color image signal obtained in this way is sent to the recording head 2.
1, 22 and the reproduction heads 23, 24 in a delay circuit 90, and then the switch 4
5 and the recording heads 21 and 22 via the head switching circuit 46.

Next, control of the drum 25 during recording of a composite color image signal will be explained. In this case, the phase control signal is obtained by comparing the phases of the reproduced vertical synchronization signal separated from the reproduced luminance signal and the vertical synchronization signal separated from the newly inputted color television signal in a phase comparison circuit 91. Use signals.
This synchronizes the timing of the reproduced color television signal and the input color television signal. The output of the phase comparison circuit 91 is supplied to the control signal addition circuit 54 via the M side terminal of the switch 53, where it is added to the speed control signal, and the drum 25
control the rotation of

The control of the capstan 58 is the same as that during normal playback, so a description thereof will be omitted. The head switching circuit 65 is controlled by a reproduced vertical synchronizing signal or a vertical synchronizing signal separated from the input television signal, and the head switching circuit 46 is controlled by a vertical synchronizing signal separated from the color image signal delayed by a delay circuit 90 or by a vertical synchronizing signal separated from the input television signal. The control signal of the switching circuit 65 is transferred to the delay circuit 9.
Control is performed using a signal delayed by a delay time of 0.

The composite color image signal recorded in this way is similar to the color image signal recorded during normal recording.
There is a correlation not every 1H, but every 2H. Therefore, the process for removing crosstalk between adjacent tracks is not the same as during normal playback. That is, during normal reproduction, the adder 81 adds 1HDL signals obtained through the C side terminal of the switch 82, but when reproducing a composite color image signal, the signals obtained through the D side terminal of the switch 82 are added. Add the 2 HDL signals.

FIG. 5 is a diagram showing the appearance on the screen when the composite color image signal obtained by the VTR of FIG. 3 is reproduced on a television receiver or the like. In FIG. 5, 1 to 263 are odd field scanning trajectories, and 263 to 525 are even field scanning trajectories. For example, if the solid line is a signal containing a color signal separated from a newly input color image signal, the dotted line is a signal containing a color signal separated from a reproduced color image signal. In this way, the same color signal on the playback screen is 1/60
Composite color image signals containing the same color signal are arranged on two scanning trajectories lined up every second.

As described above, according to the VTR shown in FIG. 3, a composite color image signal can be obtained without causing color unevenness or hue shift, and without using special techniques during photographing. Moreover, such a good composite color image signal can be obtained and recorded with a single device.

FIG. 6 is a diagram showing another embodiment in which the synthesis method of the present invention is applied to a VTR. Components similar to those in FIG. 3 are given the same numbers, and explanations are omitted.

The operations during normal recording and normal playback are the same as those of the VTR shown in FIG. 3, so the explanation will be omitted. However, in FIG. 6, the part that performs processing for removing crosstalk of color signals between adjacent tracks is omitted because it may be the same as in a conventional VTR.

The operation of recording a composite color image signal in the VTR shown in FIG. 6 will be described below. At this time, the switches 31 and 45 are each connected to the M side terminal.

The color image signals reproduced by the reproduction heads 23 and 24 are processed as described in the explanation of FIG. 3 via the head switching circuit 65, and a reproduced color television signal is obtained by the mixer 71. At this time, the head switching circuit 65 is controlled by the vertical synchronizing signal separation circuit 78.
This is done using a vertical synchronization signal separated by .
The reproduced color signal obtained by the frequency converter 79 is supplied to the C side terminal of the switch 101, and the reproduced color signal obtained by the frequency converter 79 is supplied to the C side terminal of the switch 101
The reproduced luminance signal obtained is supplied to an adder 87.

Meanwhile, a new color television signal is being supplied to terminal 28. The carrier color signal separated from this signal by the HPF 29 is supplied to the A side terminal of the switch 101, and the luminance signal separated by the LPF 30 is supplied to the adder 87. The adder 87 adds the reproduced luminance signal and the new input luminance signal to obtain a composite luminance signal, which is supplied to the mixer 34 via the M side terminal of the switch 31, the FM modulator 32, and the amplifier circuit 33. Ru. The connection of the switch 36 is switched between the A side terminal and the C side terminal every vertical retrace period by the switching signal generating circuit 100. A vertical synchronization signal separated by a vertical synchronization separation circuit 37 is supplied to the switching signal generation circuit 100. As a result, a composite color signal is obtained from the switch 101 in which the reproduced color signal and the newly input carrier color signal are alternately taken out for each field.

The synthesized color signal processed in this manner is again frequency-converted to a low frequency by the frequency converter 43, and is supplied to the mixer 34 via the amplifier circuit 44. Then, the composite color signal and the composite luminance signal are multiplexed in a mixer 34 to obtain a composite color image signal. The composite color image signal obtained in this way is sent to the recording head 2.
After delaying the delay circuit 90 according to the phase difference between the playback heads 23 and 24 and the playback heads 23 and 24, the switch 4
5 and the recording heads 21 and 22 via the head switching circuit 46.

FIG. 7 is a diagram showing the appearance on the screen when the composite color image signal obtained by the VTR shown in FIG. 6 is reproduced on a receiver or the like. In FIG. 7, 1 to 263 are the scanning trajectories of odd fields, and 263 to 52
5 is a scanning locus of an even field. For example, if the solid line is a signal containing a color signal separated from a newly input color image signal, the dotted line is a signal containing a color signal separated from a reproduced color image signal. In this way, on the playback screen, two types of color signals appear in adjacent scanning trajectories every 1/60 seconds.

In this way, the VTR shown in FIG. 6 also achieves the same effect as the VTR shown in FIG. 3.

In the apparatuses shown in FIGS. 3 and 4, most of the recording signal processing circuit and reproduction signal processing circuit are omitted for the sake of simplicity. For example, circuits that are known in conventional VTRs, such as clamp circuits, automatic gain control circuits, clip circuits, automatic phase control circuits, etc. that are less relevant to the present invention are omitted.

Furthermore, although the present invention has been explained using a VTR as an example, there are no apparatuses that can utilize the synthesis method of the present invention.
Not limited to VCRs. Furthermore, when the present invention is used in a recording/reproducing apparatus, the recording method shown in FIG. 3 is not limited to that used.

(Effects) As explained above, according to the synthesis method of the present invention,
Since only one of the two color image signals is switched and multiplexed every predetermined period, color unevenness, color shift, and even hue shift of the color burst signal do not occur as in the conventional method. Further, there is no need to perform any special operations when photographing color image signals to be synthesized, and a good synthesized color image signal can be obtained with a simple device and operation.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a VTR using the conventional compositing method, Fig. 2 is a diagram showing a state recorded on a magnetic tape by the VTR shown in Fig. 1, and Fig. 3 is a diagram illustrating the compositing method of the present invention. Figure 4 is a diagram showing a state recorded on a magnetic tape by the VTR shown in Figure 3, and Figure 5 is a composite image obtained by the VTR shown in Figure 3. Figure 6 showing the appearance on the screen when a color image signal is reproduced on a receiver, etc.
The figure shows a VTR as another embodiment using the synthesis method of the present invention, and FIG. 7 shows the VTR shown in FIG.
FIG. 3 is a diagram showing the appearance on the screen when the composite color image signal obtained in the above is reproduced on a receiver or the like. 35 is a sync separation circuit, 36 is a horizontal sync separation circuit, 37 is a vertical sync separation circuit, 38 is a changeover switch, 87 is an adder, and 88 is a changeover signal generation circuit.

Claims (1)

[Claims] 1. A first luminance signal separated from the first color image signal and a second luminance signal separated from the second color image signal.
A first color signal separated from the first color image signal and a second color signal separated from the second color image signal are added at predetermined intervals. 1. A method for synthesizing color image signals, comprising: switching to a switched color signal to obtain a switched color signal; and multiplexing the synthesized luminance signal and the switched color signal to obtain a synthesized color image signal. 2. The color image signal synthesis method according to claim 1, wherein the predetermined period is a horizontal scanning period. 3. The color image signal synthesis method according to claim 1, wherein the predetermined period is a vertical scanning period.