JPS62137703A - Video signal recording device - Google Patents

Abstract

PURPOSE:To record both the motion pictures and the still pictures (more high definite than the motion pictures) with use of the same recording device, by changing the driving speed of a recording medium carried by a carrying means and the revolving speed of a rotary head in accordance with the analog video signal or the digital video signal supplied to the rotary head. CONSTITUTION:When a switch 702 is connected to the side (a), the signals are converted into analog signals in the form of motion pictures. Then the normal analog video signals are delivered via a switch 704. When the switch 702 is connected to the side (b), the digital signals are demodulated by a digital demodulation circuit 705 and converted into the parallel 8-bit data from the serial data by a serial/parallel converting circuit 707 after error correction 706. A switch 714 is changed in accordance with the contents of the information. Then the signals are distributed to an audio decoder 710 or a video frame memory 711.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a video signal recording device, and more particularly to a video signal recording device equipped with means for recording one field of an analog video signal on one track. be.

[Conventional technology]

Conventional recording and reproducing devices of this type do not have a combined machine that can record moving images and still images separately.
TR) is used to simply play back a still image as one frame in a video in a so-called playback pause mode, and the image quality of this still image is often inferior to that of a video. .

Here, conventional so-called 8mm IJVTR still image reproduction will be explained using FIG.

In FIG. 8, 101 is a magnetic tape (hereinafter referred to as tape), 102 is a pinch roller, 103 is a capstan motor, 104 is a rotating drum, 105 is a pulse (PG) generator related to the rotational phase of the drum 104, and 106 is a generator of pulses (PG) related to the rotational phase of the drum 104. Generator of frequency signal (drum FG) related to rotation speed of drum 104, 107° 108.112, 114, 115, 11
9 is an amplifier, 109 is a drum phase control circuit, 1
10 is a drum speed control circuit, 111 and 118 are adders, 116 is a tracking error (ATF) signal generator, 113 is a frequency signal generator (capstan FG) related to the rotation speed of the capstan motor 103, and 117 is a drum speed control circuit. The capstan speed control circuits 120 and 121 are respectively magnetic heads (hereinafter referred to as heads).

In FIG. 8, the rotary drum 104 adds the phase error signal from the phase control circuit 109 and the speed error signal from the speed control circuit 110 in an adder 111 based on the drums PG and FG. It is driven by the signal. The rotation of the drum 104 is thereby controlled so as to correct these errors.

On the other hand, the capstan motor 103 receives a speed error signal from a speed control circuit 117 based on the capstan FG, as well as an ATF (Automatic Trac) signal from an ATF signal generator 116 using a four-frequency pilot method.
Tracking control is performed using the king pinding) signal.

° Therefore, in the still image playback state, (1) or (1) in Figure 9
The head is controlled by the circuit shown in FIG. 8 so that it traces the magnetic tape as in 1).

Figure 9 shows (1) 5η frame still playback and (1)
1) A diagram showing the trace state of a head on a tape during so-called field still playback. FIG. 9 will be explained below.

In FIG. 9, (1) frame/still reproduction is one in which two field tracks are alternately reproduced, and two heads A and B are used to alternately reproduce only tracks whose azimuth matches each other. Therefore, as shown in the figure, the reproducing area for each disc becomes about + that in the case of normal reproduction, and the S/N ratio deteriorates. Furthermore, since the video signals of these two fields have a time difference of 1/60 second, there is a risk that a still image will be blurry in a fast-moving scene.

(+r>Field still playback uses a dedicated head for still images (180°
The data is repeatedly reproduced using two heads with the same azimuth and different phases. Therefore, blurring like frame still playback does not occur, but compared to normal playback, S/
Deterioration of N, vertical resolution, etc. cannot be avoided in principle.

[Intermediate point that the invention attempts to solve]

Generally speaking, human visual characteristics require higher image quality for still images than for moving images. Furthermore, in the case of still images, it is possible to print them out and fix them on paper for viewing, so even higher image quality is required. but,
Still images captured by conventional VTRs have a disadvantage in that their image quality is degraded compared to moving images due to the reasons mentioned above.

The present invention has been made in view of these drawbacks, and it is an object of the present invention to provide a video signal recording device that is capable of recording moving images and still images with higher definition than the moving images using the same device.

[Means for solving problems]

For this purpose, the video signal recording device according to the present invention has a video signal recording device that runs a recording medium in the longitudinal direction.
! a rotary head for tracing the traces, means for supplying analog video to the rotary head, means for digitizing the analog video signal, and means for digitizing the analog video signal; a means for supplying a digital video signal to the rotary head; and a speed at which the recording medium is run by the conveying means depending on whether the analog video signal or the digitized video signal is supplied to the rotary head. and means for switching the rotational speed of the rotary head.

[For production]

In the above configuration, if it is desired to record a high-definition video signal, it is necessary to record the digitized video signal at a high relative speed and on a track having the same slope as the track of a normal analog video signal. I can do it.

〔Example〕

The basic concept when applying the present invention to a VTR will be explained below.

Generally, the optical system of a commercially available video camera has sufficient bandwidth for video recording using a VTR. Therefore, the same optical system is used to supply signals to a still image signal processing circuit in addition to a moving image signal processing circuit. This still image signal processing circuit digitizes and records the supplied signal.

At this time, the number of rotations of the head is increased in order to record a broadband still image signal, but simply increasing the number of rotations of the head does not change the angle of inclination of the trunk on the tape compared to when recording an analog video signal. Resulting in. Therefore, when the number of rotations of the head is increased by N times (N>1), the number of rotations of the capstan is also increased by N times.

Furthermore, by recording in accordance with the audio recording format of an 8 mm VTR as the digital recording format at this time, part of the signal processing circuit can be shared. However, as will be explained later, there is an identification (
ID) Record the signal data.

Furthermore, since the amount of still image data in the same period is significantly different from the amount of audio data, the analog-to-digital converted video signal is stored in the frame memory at the timing corresponding to the shutter release of the camera. is stored in Digital video data is then read out from the frame memory at a transmission rate that corresponds to the recordable band.
Record on tape.

FIG. 1 is a block diagram showing a schematic configuration of a signal processing system of an apparatus according to an embodiment of the present invention, in which 500 is an analog video signal processing circuit of the moving image layer, 501 is an electromagnetic conversion system,
502 is a magnetic tape, 503 is a PCM signal processing circuit, 5
04 is an optical system, 505 is an image sensor, 506 is a digital video signal processing circuit for still images, 507 is a control circuit, and 508 is a switch.

The device shown in FIG. 1 has three circuits added to the circuit configuration of a conventional camera-integrated 8 mm VTR: a still image signal processing circuit 506, a still image signal control circuit 507, and a moving image/still image switching circuit 508.

FIG. 2 shows the still image signal processing circuit 506 and PC of FIG.
This figure shows the details of the M signal processing circuit 503, and in the figure, 601 is an analog/digital converter (hereinafter referred to as A/D).
(referred to as D converter), 602 is a frame memory composed of RAM, 603 is a system controller, 604
is an address generator, and 605 is a switch.

First, an image is formed on the sensor 505 by the optical system, and its output is supplied to the A/D converter 601. A/D
All the information digitized by the converter 601 is
It is temporarily stored in the frame memory 602. Writing control to the 7-frame memory 602 is controlled by the system controller 6.
03, is performed by the address generator 604.

Now, when the shutter release instruction enters the system controller 603, it sends the address reset instruction to the response generation a60+, starts writing from the first address of the frame memory 602, and when it is finished, it outputs an end pulse to that effect. It is returned to the system controller 603. In response to this end pulse, controller 603 then issues a low speed read instruction. Here, low speed means that the transmission rate is low, and the time axis is expanded on the time axis. The data is supplied to the redundant data addition circuit 605 in 503, and redundant codes such as ID and error correction code (FCC) are added thereto, and then modulated in the modulation circuit 606 and sent to the next switch (508).
It is supplied to the S side terminal of Fig. 1).

Regarding the processing of the output signal of the switch 508, the conventional VT
It is recorded on the tape 502 by the electromagnetic conversion system 501 in the same manner as R.

Here, the data amount of the still image video signal will be described below.

FIG. 10 shows the recording format of PCM audio signals in an 8 mm VTR.

In Fig. 5, 5ynC is synchronization data, AO~A1
31 are address data, DO~ID5 are additional data, RO~R524 are right channel audio data, LONL524 are left (υ channel audio data, QO~Q131.PO-P131 are error corrections) CRC is a well-known cyclic code for error detection.RO~R524, LONL52
4 are 8-bit data words each. These are recorded per field period of the video signal.

In FIG. 6, 401 is an area in which one field of analog video signal is recorded per one track, and 402 is a time-base compressed PCM of one field period per one track.
This is an area where audio signals are recorded in the format described above.

Therefore, the stereo signal, including the R channel, is 1
050 words of information can be recorded in each field. Here, 1 word = 8 pinpoints, so if the video signal is quantized with 8 bits, the amount of data corresponds to exactly one pixel. Now, the number of pixels to be digitized is (500X500
), one frame is (500 x 5
Since the number of words in the audio area per second is 1050x60 words, to record a still image using this format,
A recording time of 12) seconds in 0x3)/(1050x60) is required per frame.

In addition, even in the composite method that digitizes the luminance signal and color signal without separating them, the sampling frequency is 3 fsc (fs
c is the color subcarrier frequency), approximately 4 seconds are required.

Therefore, each track of such recording is divided into 6 parts.
When using the format for recording channel audio signals, the amount of information that can be recorded per field period is 6.
Since the time required for recording is doubled, the time required for recording is reduced to 1/6.

Therefore, in this case, the time is 2 seconds for the component method, and less than 1 second for the hunposite method when the sampling frequency is 3 fsc. 403 of the 1111th ffi shows the recording pattern at this time, and M'yFM shows the relationship between the number of bits and processing time and the processing time for each sampling method.

In Figure 7, A in the diagram is a combo.

When the sampling layer wave number is 3 fsc in the composite method, B is 4 fsc in the composite method, and C is
represents the above relationship based on the component method using the number of pixels described above.

However, as it is, it is not as good as a popular single-lens seven-lens camera in terms of continuous shooting (continuous shooting), so the following processing is performed to shorten the recording time. That is, an example will be described in which data of a composite video signal conforming to the NTSC system is recorded in the recording format of the 6-channel PCM audio signal as described above.

As mentioned above, the time required to record information in a 6-channel PCM7 format is about 2/3 seconds, and in a conventional VTR, about 60 tracks are recorded during this time. In order to record these 60 trunks in a short time, both the tape feeding speed and the drum rotation speed are increased. If you do this, 6
With the channel PCM format, recording time can be shortened without changing the track formation direction.

FIG. 6 clearly shows the relationship between the rotational speed and the amount of recorded data, and it can be seen that as the speed increases, the processing capacity per unit time increases.

Next, a specific example will be explained.

FIG. 3 is a block diagram showing a schematic circuit configuration of a rotation control system of an apparatus according to an embodiment of the present invention. In the figure, 12
2, 123 is a switch for switching the reference voltage, 124 is a frequency divider with a frequency division ratio of 1/N, and 126 is the switch 122, 12.
3, and the same reference numerals as in FIG. 8 indicate the same or corresponding parts.

In FIG. 3, the speed control reference voltage AI for standard speed,
Two types of reference voltages are prepared: Ax (At is for the drum, A2 is for the capstan) and speed control reference voltage Bl for high speed, B2 (Bs is for the drum, B2 is for the capstan). Switch in conjunction with the operation panel. In conjunction with this, the processing speed of the PCM signal processing circuit 503 of the signal processing system is also increased (i.e., the output redundancy addition circuit 606 of the address generator (604 in FIG. 2), which is a signal for controlling readout of the frame memory. and the processing speed of the modulation circuit 607
This is N times the number when processing M audio signals.

Incidentally, the processing during digital recording of the drum PG will be explained using FIG. 4. Figure 4 shows the 30Hz signal PG synchronized with the rotation of the rotating drum during normal analog recording, the waveforms when the drum is rotated at 3x speed during digital recording, the frequency division 6124 at that time, and the monomulti A timing chart of each output waveform of the vibrator 125 is shown. For example, when N=3 and the drum is rotated at 3 times the speed, the frequency divider 124 is also set to a + division ratio, and in combination with the mono multi-vibration break 125, the same / I'm getting a russ column.

In FIG. 3, switching between the PG output of the amplifier 107 for standard speed recording and the processed pulse output of the mono-multivibrator is performed by a switch 126 in conjunction with other switches 122 and 123.

In the manner described above, high-speed recording becomes possible and recording time can be shortened.

Further, FIG. 5 shows a block diagram of a reproducing circuit corresponding to the recording apparatus as described above. In Figure 4, 700 is a tape, 701 is an electromagnetic conversion system, 702, 704, 714
is a switch, 703 is an analog video signal processing circuit, 7
05 is a digital demodulation circuit - 706 is an error correction circuit, 7
07 is a serial-parallel conversion circuit, 708 is an ID detection circuit, 7
09 is a system controller, 710 is an audio decoder, 711 is a frame memory, 712 is an address generator, and 713 is a digital/analog converter (D/A converter).

Now, the information recorded on the tape 700 is reproduced as an electrical signal by an electromagnetic conversion system 701 composed of a head, a rotary transformer, and the like. This signal is supplied by a switch 702 to either an analog video signal processing circuit 703 or a still image processing circuit including a digital demodulation circuit 705. If the switch 702 is connected to the a side, the signal is processed as an analog signal as a moving image,
It is output as a normal analog video signal via switch 704.

On the other hand, if the switch 702 is connected to the b side, the signal is demodulated as a digital signal by the digital demodulation circuit 705, error corrected by the error correction 706, and converted from serial data to parallel 8-bit data by the serial-parallel conversion circuit 707. be done. A switch 714 is switched depending on the content of the information, and the information is distributed to the audio decoder 710 or the video frame memory 711. The switching of this switch 714 allows identification information regarding whether the aforementioned audio data included in the playback signal is still image data to be input along with other additional data.
Detected by the D detection unit 708, the system controller 70
It is controlled by 9. The system controller 709 also controls the switch 70 based on the operation of an operation section (not shown).
Switch 2,704. Furthermore, the controller 709
determines the address data generated by the address data generator 712. Writing and reading to and from frame memory 711 are controlled according to the address of address generator 712.

In this way, the data string read out in a sequence that reproduces the form of the video signal is transferred to the D/A converter 713.
The signal is then supplied to the switching switch 704 as an analog signal. A video signal of a still image or a moving image is output from the switch 704 depending on the recording mode.

〔Effect of the invention〕

According to the present invention, as explained above, it is possible to record a moving image and a still image with higher resolution than the moving image on the same recording medium using the same device, and at the same time, the recording time of the still image can be shortened and the recording trunk pattern can be changed. A video signal recording device can be obtained which can be made identical.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a recording apparatus signal processing system as an embodiment of the present invention, FIG. 2 is a block diagram showing details of the still image signal processing circuit and PCM signal processing circuit of FIG. 1, FIG. 3 is a block diagram showing a schematic circuit configuration of a rotation control system of a recording apparatus which is an embodiment of the present invention;
The figure is a timing chart showing the waveforms of each part in FIG. 3, FIG. 5 is a block diagram of a reproducing circuit corresponding to the recording device shown in FIG. 7 is a diagram showing the relationship between the amount of information of a digital still image signal and the recording time. FIG. 8 is a diagram showing the main part configuration of the rotation control system circuit in a conventional VTR. Figure 9 shows the positional relationship between the tape and head for still playback in a conventional VTR, Figure 10 shows the recording format of PCM audio signals in an 8mm VTR, and Figure 11 shows the positional relationship between the tape and the head for still playback on a magnetic tape. FIG. 3 is a diagram showing a recording pattern of FIG. In the figure, 103 is a capstan motor, 104 is a drum, 122 and 123 are reference voltage changeover switches, and 126
500 is a switch, 500 is an analog video signal processing circuit for moving pictures, 501 is an electromagnetic conversion system, 502 is a magnetic tape, 50
3 is a PCM signal processing circuit, 504 is an optical system, 505 is an image sensor, 506 is a still image signal processing circuit, 507 is a control circuit, and 508 is a switch.

Claims (1)

[Claims] A conveying means for running a recording medium in a longitudinal direction, a rotating head for tracing in a direction crossing the running direction of the medium, a means for supplying an analog video signal to the rotating head, and a means for digitizing the analog video signal. a means for supplying the digitized video signal to the rotary head; and a means for supplying the digitized video signal to the rotary head; A video signal recording device comprising means for switching the running speed of a recording medium and the rotational speed of the rotary head.