JPS5941355B2 - Still image recording and playback device - Google Patents

Description

Detailed Description of the Invention The present invention combines a VTR (video tape recorder) that records and plays back video signals using a magnetic tape as a recording medium and a VSR (video sheet recorder) that records and plays back video signals using a magnetic sheet as a recording medium. In preparation, for example, an arbitrary field of a video signal played by a VTR was extracted and recorded on a magnetic sheet by a VSR, and this was continuously played back by the VSR to obtain a still image for motion analysis. The present invention relates to a still image recording and reproducing device.

According to the present invention, a color video signal to be recorded or reproduced has a relationship in which the carrier color signals are interleaved between every other track and every other remaining track, whereby the carrier color signals between adjacent tracks are interleaved. This is applied to a VTR in which crosstalk components can be removed using a comb filter.

In a VTR, when recording a color video signal, the luminance signal is FM-modulated, the carrier color signal is frequency-converted to a low carrier frequency signal, and both are multiplexed and recorded. In this case, the modulated luminance signal is a rotary two-head type VT
By making the angles formed by the extending directions of the gaps of the two R magnetic heads and their scanning directions different from each other, it is possible to suppress crosstalk components from adjacent tracks by utilizing azimuth loss. In addition, the converted carrier color signal is recorded on every other track and the remaining track is recorded, and the carrier frequency for low frequency conversion is the difference in DL (where fh is the horizontal frequency). By interleafing the signals, crosstalk components of adjacent tracks can be reduced by passing through a comb filter during playback.

In addition, even if there is only one type of carrier frequency, the phase of the carrier wave for low frequency conversion of the carrier color signal recorded on every other track is kept constant, and the phase of the carrier wave for low frequency conversion of the carrier color signal recorded on every other track is kept constant. Even if the phase of the carrier wave for NTSC color television signals is inverted every horizontal interval (every two horizontal intervals in the case of PAL color television signals), a frequency interleaf relationship can be achieved in the same way; When using carrier waves of different frequencies, the carrier wave for low frequency conversion of the carrier color signal recorded on every other track and the carrier wave for low frequency conversion of the carrier color signal recorded on the remaining every other track. A frequency interleaf relationship can be similarly achieved by shifting both by a predetermined phase amount every horizontal section (every two horizontal sections in the case of the PAL system) and in opposite directions for adjacent tracks. The present invention aims at simplifying the configuration by using a common video signal processing circuit for a VTR and a VSR using such a recording/reproducing method. Furthermore, by repeatedly reproducing one field of video signal, the present invention enables fast-moving video to be reproduced as completely still, compared to repeatedly reproducing one frame of video signal. It is. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 indicates a magnetic tape, and the magnetic tape 1 is pulled out from a tape cassette 2 (indicated by a two-dot chain line). It is wound around the circumferential surface of the guide drum 3 in an Ω shape over an angular range of 1800 or more, and in this state is run at a constant speed by the capstan 4 and the pinch roller 5.

For example, the tape guide drum 3 is directly connected to the shaft 6a of the motor 6 and rotates at 30 revolutions per second, and two magnetic heads (not shown) rotate integrally with the tape guide drum 3 at an angular interval of 180 revolutions. be made to do. The angles that the extending directions of the respective gaps of this magnetic head make with the scanning direction differ by about 15 degrees. In the configuration shown in Figure 1, the recording system is omitted for simplicity, but
As shown in FIG. 2, the magnetic tape 1 has a track 7a on which one field of color video signals is recorded by one magnetic head, and a track 7b on which one field of color video signals is recorded by the other magnetic head. are formed alternately without intervening no-signal areas called guard bands. As shown by the arrows in each horizontal section in FIG. 2, the phase of the carrier wave for low frequency conversion is set to a constant phase in the field corresponding to the track 7a formed by one magnetic head, and the phase of the carrier wave formed by the other magnetic head is set to a constant phase. In the field corresponding to track 7b, the phase of this carrier wave is inverted every horizontal section, so as to avoid any adverse effects due to crosstalk components between tracks, as described above. Further, reference numerals 8a and 8b indicate pickup coils arranged at an angular interval of 180 degrees, and 1 which is not shown rotates integrally with the tape guide drum 3, that is, the magnetic head.
The period defined by the detection pulses taken out from the pickup coils 8a and 8b to the terminals 9a and 9b is the track 7a.
Alternatively, it is defined to correspond to the period of one field in which the reproduction output is taken out from each of the fields 7b. Also, 1
0 indicates a disk-shaped magnetic sheet in which a plurality of circular tracks are formed concentrically.

This magnetic sheet 10 is fitted onto the rotating shaft 6b and rotated. In this example, a VTR and a VSR are integrated into an integrated device in which not only the tape cassette 2 but also the magnetic sheet 10 can be attached, so the magnetic sheet 10 is housed in a thin case 11 (indicated by a two-dot chain line). When replacing the magnetic sheet 10, the entire case 11 is replaced. Further, a gear 12b is fixed to the rotating shaft 6b, and a gear 12 is fixed to the rotating shaft 6a of the motor 6.
The rotating shaft 6b is driven by a timing belt 13 that is placed between the gear 12b and the gear 12b. In this case, the gears 12a and 1 are set so that the video signal recorded on the magnetic sheet 10 by one rotation is an integral multiple of the horizontal interval.
A tooth ratio of 2b is selected. This is magnetic sheet 10
This is to prevent the image quality of the raw screen from deteriorating due to jamping of the horizontal synchronization signal occurring at the part where the start and end of the track meet when recording one field of video signal as one circular track. be. Further, 14RP indicates a recording/reproducing head, and 14E indicates an erasing head. These recording/reproducing head 14RP and erasing head 14E are connected to the magnetic sheet 1
Track switching is performed by moving integrally in the radial direction of zero. 15 is for this reason the recording/playback head 14RP.
and a step motor for moving the erasing head 14E in the radial direction of the magnetic sheet 10.

The above configuration is a VSR configuration. Note that the tape guide drum 3 may be rotated via a belt or the like without being directly connected to the shaft 6a of the motor 6, and the magnetic sheet 10 may be rotated by a motor separate from the tape guide drum 3. .

In addition, the recording/reproducing head 14RP or the erasing head 1 of the VSR
4E can be moved into and out of contact with the magnetic sheet 10 using a piezoelectric element, etc., and the two may be brought into contact only when the VSR performs recording or reproducing operations, or when the VSR is reproducing still images, the magnetic tape 1 At the same time as stopping the running of the magnetic tape 1 or the magnetic sheet 10, the tension is loosened so that there is almost no contact between the magnetic tape 1 and the rotating magnetic head, thereby preventing damage caused by scanning the same part of the magnetic tape 1 or the magnetic sheet 10 for a long time. It may be possible to prevent this from occurring. Now, the high frequency color video signal reproduced from the VTR is sent to the reproduction output switching circuit 22 via the preamplifier 21.
is supplied to the TR side terminal 23a, and this reproduction output switching circuit 2
A high pass filter 24 connected to the output terminal 23c of 2
and the low-pass filter 25.

The modulated luminance signal separated by the high-pass filter 24 is supplied to the FM demodulator 27 via limiter circuits 26a and 26b, and a luminance signal appears at the output of the FM demodulator 27. On the other hand, the converted carrier color signal separated by the pass filter 25 is sent to the frequency converter 29 via the ACC circuit 28.
supplied to The carrier frequency of the converted carrier color signal is, for example, (
44--)Fh, and the frequency converter 29 receives {Fs
+(44-1)Fh} (where F is the color subcarrier frequency, approximately 3.58MHz in the NTSC system) is supplied, and is converted to a carrier color signal with Fs as the carrier frequency, and the pad After unnecessary signal components are removed by a bus filter 30, the signal is supplied to a comb filter 31. The carrier color signal from which crosstalk components have been removed by the comb filter 31 and the luminance signal from the FM demodulator 27 described above are applied to a mixer 32, and the color video signal appearing at the output of the mixer 32 is sent to a muting circuit 33. is guided to the video output terminal 34 via. A monitor receiver is connected to the video output terminal 34. Further, the muting circuit 33 cuts off the video signal component of the color video signal during the muting operation, but guides the vertical and horizontal synchronizing signals to the video output terminal 34 without blocking them. Further, 35 is an APC circuit, and its error output controls a variable frequency oscillator 36 whose center frequency is (Fs--Fh).

37 is an AFC circuit, and the AFC circuit 37 is supplied with a horizontal synchronization signal separated by a horizontal synchronization separation circuit 38 from the output of the mixer 32, and 44fh synchronized with this horizontal synchronization signal.
A signal with a frequency of is formed and applied together with the output of the variable frequency oscillator 36 to the frequency converter 39, from which a signal with a frequency of {F8+(44-1)Fh} appears.

The output of this frequency converter 39 is supplied to a phase inverting transformer, and further supplied to the frequency converter 29 via a phase switching circuit 40. The phase switching circuit 40 sets the phase of the carrier wave to correspond to the scanning of the tracks 7a and 7b by the magnetic head. That is, when one magnetic head scans the track 7a, the phase of the carrier wave is kept constant, and when the other magnetic head scans the track 7b, the phase of the carrier wave is inverted every horizontal section, and this The phase inversion for each horizontal section corresponds to the phase inversion of the recorded carrier wave. As a result,
The phase of the carrier wave of the carrier color signal obtained as the output of the frequency converter 29 is aligned to the same phase regardless of whether it is the reproduction output of the track 7a or 7b, and the comb filter 31 in the next stage removes crosstalk components. It can be done. As described above, there are two reproduction modes for the color signal reproduction system: a mode for reproduction output from every other track 7a, and a mode for reproduction output from the remaining every other track 7b.

Therefore, an identification circuit 41 is provided for performing field identification and line identification, and the output of this identification circuit 41 controls switching of the phase switching circuit 40. Field identification (i.e. identification of tracks 7a and 7b) is provided by the output of flip-flop 42, to which the detection pulses from terminals 9a and 9b are applied via an amplifier to its set and reset terminals. The field period switching pulse P1 appearing at the output of the flip-flop 42 is at a low level in the scanned field of the track 7a, and at a high level in the scanned field of the track 7b. The signal is applied to the identification circuit 41 via the identification circuit 41. Line identification is performed by phase-detecting the carrier color signal using a continuous wave synchronized with the phase of the burst signal in the carrier color signal taken out from the APC circuit 35 and generated by the continuous wave generating circuit 44. It will be done. By this line identification, the polarity of the horizontal synchronization signal from the horizontal synchronization separation circuit 38 is controlled to form a switching pulse with a line period, and the combined pulse of the field period and line period switching pulse is used to control the phase switching circuit. 40 is controlled. The above is the reproduction system of a VTR.

The recording/reproducing head 14RP of the VSR is connected to a recording/reproducing switching circuit 45, and a high frequency color video signal defined by a recording gate circuit 47 as the length of one field is supplied to its recording side terminal 46r. This high frequency color video signal is taken out from the output of the limiter circuit 26a and is sent to the amplifier 4.
The modulated luminance signal passed through the ACC circuit 8 and the converted carrier color signal taken out from the output of the ACC circuit 28 and passed through the amplifier 49 are added together by the mixer 50. Further, the reproduction signal from the magnetic sheet 10 taken out from the reproduction side terminal 46p of the recording/reproduction switching circuit 45 is supplied to the SR side terminal 23b of the aforementioned reproduction output switching circuit 22 via the preamplifier 51. The aforementioned reproduction system is connected to this reproduction output switching circuit 22, so that the VTR and VSR have a common reproduction system. Further, an erase bias signal from an erase bias oscillator 53 is supplied to the erase head 14E of the VSR via an erase bias supply switch 52. Further, there are a playback switch Sp that is turned on when reproducing a still image, a recording switch Sr that is turned on when recording a still image, and a track changeover switch St that is turned on when switching tracks of the magnetic sheet 10. A switch control signal forming section 54p and a recording erase command forming section 5 are provided in connection with these operation switches.
4r, a track switching pulse forming section 54t is provided.

A switch control signal P corresponding to the on/off state of the reproduction switch Sp generated from the switch control signal forming section 54p
2, the aforementioned reproduction output switching circuit 22, reproduction mode fixing switch 43, recording/reproduction switching circuit 45, and erase bias supply switch 52 are controlled. Record erasure command forming unit 54
r generates an erase command P3 corresponding to the length of one predetermined field after turning on the recording switch Sr and a recording command P4 for the length of one field after that, and this recording command P4
The recording gate circuit 47 is turned on by this. Therefore, the recording/erasing command forming section 54r includes a flip-flop 42.
A switching pulse P1 having a field period of
The field signals are recorded on the magnetic sheet 10. Further, the operation of the recording switch Sr is enabled only when the reproduction switch Sp is off. Furthermore, the switch control signal forming section 54p is put into the same state as when the playback switch Sp is off when the power is turned on or when a control pulse indicating that the VTR is in the recording or playback state is supplied from the terminal 56. The SR is set in a recording preparation state when the power is turned on or when the VTR is in a recording or reproducing state. Further, track switching pulses from the track switching pulse forming section 54t are supplied to the step motor 15 via the drive circuit 57 to perform track switching.

This track switching pulse is automatically generated at the trailing edge of the recording command P4 in addition to the operation of the track switching switch St. The muting signal generator 58 detects when the switch control signal P2 changes to a high level on the reproduction side, for example, and when a track switching pulse is generated, and the vertical sync signal is separated from the reproduced color video signal by the vertical synchronization separation circuit 59. A muting signal for a period of, for example, 10 fields is generated from the above-mentioned detection time in synchronization with the synchronizing signal, and the muting circuit 33 is caused to perform a muting operation based on this muting signal. An embodiment of the present invention having the above-described configuration will be described in detail along with its operation.

First, the operation of extracting the reproduction output from the magnetic tape 1 with a VTR and recording an arbitrary image as a still image on the magnetic sheet 10 while viewing the reproduced image will be explained with reference to FIG. At this time, the switch control signal P2 is at a low level, so as shown in FIG. 1, the reproduction output switching circuit 22 is connected to the VTR side, the reproduction mode fixing switch 43 is set to the non-fixed side, and the recording The reswitching circuit 45 is connected to the recording side terminal 46r, the erasing bias supply switch 52 is turned on, no muting signal is generated, and the video output terminal 34 receives a color video signal demodulated from the playback output of the VTR. You can watch the playback video on the monitor receiver. Here, FIG. 3A shows a switching pulse P1 with a field period, the low level field Ta is the period for taking out the playback output from the track 7a, and the high level field Tb is the period when the reproduction output is taken out from the track 7a.
This is the period during which the reproduced output is extracted from b. This switching pulse P1 is differentiated by a differentiating circuit 55, and the differentiated pulse shown in FIG. 3B is supplied to the recording/erasing command forming section 54r. Then, when the recording switch Sr is turned on at time t1 as shown in FIG. As shown in Figure 3E, time T2
An erasure command P3 for one field from to time T3 is generated, and a recording command P4 for the next one field from time T3 to T4 (FIG. 3F) is generated. During one field in which the erase command P3 is generated, the erase bias oscillator 53 operates to supply an erase bias signal to the erase head 14E, and during one field in which the record command P4 is generated, the recording gate circuit 47 is turned on. The reproduction signal from the track 7a is supplied to the recording/reproducing head 14RP via the recording gate circuit 47 and the recording/reproducing switching circuit 45, and is recorded on the magnetic sheet 10. Further, at the trailing edge of this recording command P4, a track switching pulse is generated as shown in FIG. 3G, and track switching is performed. With the above steps, one still image is recorded on the magnetic sheet 10. Next, at time T5, the recording switch S is turned on again.
When r is turned on, the timing is taken up to the time point T6 when a positive differential pulse appears, and from this time point T6, an erase command P3 for one field and a record command P4 for the next one field are generated, and at the trailing edge of the record command P4. The track switching pulse is generated in the same way as described above. In this way, one of the reproduced signals of the VTR is extracted from one track 7a.
The fields are recorded on the magnetic sheet 10. To play back the still images recorded as above, press the playback switch S.
This is done by turning on p. Playback switch Sp
When turned on, the switch control signal P2 becomes high level,
The reproduction output switching circuit 22 is connected to the VSR side, the reproduction mode fixing switch 43 is connected to the grounded fixed side,
The recording/reproducing switching circuit 45 is connected to the reproducing side terminal 46p, and the erasing bias supply switch 52 is turned off. Therefore, when the recording/reproducing head 14RP repeatedly scans the same track, the reproduction signal extracted from the magnetic sheet 10 is transferred to the recording/reproducing switching circuit 45, the preamplifier 51, and the reproduction output switching circuit 22.
is given to the regeneration system via. Among these reproduction systems, the luminance signal reproduction system operates in the same way as for the reproduction output of a VTR, but in the color signal reproduction system, the switching pulse of the field period is fixed at a low level, so the carrier wave for low frequency conversion is The phase of is fixed to a constant value. This is because the high frequency color video signals recorded on the magnetic sheet 10 are limited to those reproduced from the track 7a.
Therefore, a good still image free from the influence of crosstalk components can be viewed on the monitor receiver connected to the video output terminal 34. Furthermore, when the track changeover switch St is turned on, a track changeover pulse is generated, the track is changed over, and another still image can be viewed.If the VTR is placed in the recording state or the playback state during such still image playback, the switch control signal P2 becomes low level, and the SR automatically switches from the playback state to the recording preparation state. FIG. 4 is a time chart used to explain the muting operation of the muting circuit 33.

FIG. 4A shows the vertical sync pulse separated from the reproduced color video signal. First, to explain the case of switching from the VTR playback output to the VSR playback output, as shown in FIG. The reproduction output is supplied to the reproduction system. Since there is no defined time relationship between the reproduced output of the TR and the reproduced output of the VSR, the vertical synchronization signal during the reproduced output of the VSR is the vertical synchronization signal during the reproduced output of the TR shown by the broken line in FIG. 4A. The signal will be out of phase. Muting signal generator 5
8 contains the switch control pulse P2 shown in FIG. 4C.
A time point T2 rises from the differential pulse corresponding to the leading edge of , and coincides with the vertical synchronization signal separated from the reproduction output of the VSR.
Form a timing pulse (Fig. 4E) that falls at
Muting signals for 10 fields from the fall of this timing pulse to time T3 are output. The generation of this muting signal takes place, for example, by means of a monostable multivibrator of the retriever type. Due to this muting signal, the muting circuit 33 sends only vertical and horizontal synchronizing signals to the video output terminal 34 for 10 fields.
Since the monitor receiver connected to the The still images played back are stable and do not suffer from the negative effects of vertical shaking on the screen. On the contrary, VS
A similar muting operation is performed when switching from the R reproduction output to the VTR reproduction output. Next, when the track changeover switch St is turned on at time T4, a track changeover pulse shown in FIG. 4D is generated.

Since there is no prescribed time relationship between the signals reproduced from each track of the magnetic sheet 10, the vertical synchronization signal being reproduced from one track and the signal from the next track are different from each other as shown by the broken line in FIG. 4A. The phase of the muting signal generator 58 is shifted from the vertical synchronization signal being reproduced and output from the new track, and as shown in FIG. The timing up to T5 is taken, and from this time T, to time T
Up to 6 10 field muting signals are generated. Muting circuit 3 using this muting signal
The operation of step 3 is the same as described above. Furthermore, when switching between the VTR playback output and the VSR playback output and track switching are performed almost at the same time, the muting signal is generated by the retriker type monostable multivibrator. The muting operation can be performed for a certain amount of time (a period of 10 fields in this example). As is clear from the foregoing, according to the present invention, when the recording format of the carrier color signal differs between every other track and every other track of the VTR, the signal of only one recording format is transmitted. A still image is recorded on the magnetic sheet 10, and when the still image is reproduced, the reproduction mode of the color signal reproduction system is fixed to the one corresponding to the signal recorded on the magnetic sheet 10, so the VTR
The color signal reproducing system of the VSR and VSR can be shared, and the circuit configuration can be simplified. In addition, any image reproduced by a VTR can be immediately recorded as a still image, and motion analysis can be performed.
By alternately reproducing still images from the SR, the required length of the magnetic tape 1 can be shortened, and an image that serves as an index for the video recorded on the magnetic tape 1 can be recorded and stored on the magnetic sheet 10. It is now possible to keep the However, in the present invention, since a still image is formed using one field signal, a completely stopped image can be obtained compared to a still image formed using one frame signal. In the above embodiment, one field of the reproduction output of the VTR is recorded on the magnetic sheet 10 by the SR, but during the recording operation of the VTR, the high frequency color video signal to be recorded is recorded on the magnetic sheet 10 by the VSR. You may also do this.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a recording pattern of a magnetic tape, and FIGS. 3 and 4 are waveform diagrams used to explain the operation of an embodiment of the present invention. . 1 is a magnetic tape, 3 is a tape guide drum, 8a and 8b are pickup coils, 10 is a magnetic sheet, 14RP is a recording/reproducing head, 14E is an erasing head, 22 is a playback output switching circuit, 29 and 39 are frequency converters, and 33 is a 40 is a phase switching circuit, 43 is a reproduction mode fixing switch, 45 is a recording/reproduction switching circuit, Sp is a reproduction switch, Sr is a recording switch, and St is a track switching switch.

Claims (1)

[Claims] 1. A magnetic tape playback machine that plays back color video signals from a magnetic tape, a magnetic sheet recording and playback machine that records and plays back color video signals using a magnetic sheet, and video of one field period from the playback output of the magnetic tape playback machine. comprising a gate circuit that extracts a signal and supplies it to the magnetic sheet recording/reproducing machine, and a reproduction signal supply circuit that continuously supplies the reproduction signal from the magnetic sheet recording/reproducing machine to the reproduction circuit of the magnetic tape reproduction machine, The above magnetic tape reproducing machine reproduces signals in which the phases of the carrier color signals are interleaved between every other track and every other remaining track, and reproduces the interleaved carrier color signals. The magnetic tape reproducing apparatus further comprises a color signal reproducing circuit for eliminating signal crosstalk between adjacent tracks on the magnetic tape by controlling the phase relationship using a carrier wave for frequency conversion in synchronization with the switching of the tracks. When recording the reproduction signal from the reproduction head on the magnetic sheet recording/reproducing machine, a color video signal corresponding to every other track is generated by a reproduction mode switching signal synchronized with this recording timing and the switching of the tracks. One field is extracted and recorded by the gate circuit, and when reproducing the recorded signal, a still image obtained by repeatedly reproducing the magnetic sheet is sent to the magnetic tape reproducing machine via the reproduced signal supply circuit. A still image recording and reproducing device, wherein the phase of the carrier wave that is supplied to a color signal reproducing circuit and that controls the color signal reproducing circuit corresponds to the relationship between the carrier color signals recorded on the magnetic sheet.