JPS62185479A - Still picture recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention records input video signals as still images.

It relates to a still image recording and reproducing device that reproduces video signals such as television signals intermittently using a rotating recording medium (small magnetic sheet) in which video signals for one field are concentrically recorded in one rotation. The present invention relates to a still image recording and reproducing device suitable for recording and reproducing still images to obtain high quality decomposed photographic images.

[Background of the invention]

2. Description of the Related Art Recently, an electronic camera has been announced as a device as described above that records and reproduces still images using a small magnetic sheet as a rotating recording medium.

This device uses a shutter on a solid-state image sensor used in a video camera to capture a single frame image, and then magnetically records the image on a rotating magnetic sheet, allowing it to be processed and processed like a conventional film camera. It does not require any processing and can be played back as a still image on a home TV immediately after being shot.

In order to achieve the same size as a conventional film camera, a small magnetic sheet with a diameter of 47 mm was used, and one rotation of the magnetic sheet recorded one field of video signals, and 50 magnetic sheets were placed in a concentric circle. A track is formed on the sheet so that 50 still images can be recorded.

By combining this magnetic sheet with a television receiver as a still image memory, the television screen can be saved as a still image instead of a memo. Furthermore, if a moving scene is recorded intermittently, it is possible to reproduce an image similar to a decomposed photograph.

However, conventional devices do not take into consideration which of the two fields of the video signal to record, and as a result, when the track is moved during playback, skew occurs on the monitor, deteriorating the playback image quality. There's a problem.

This point will be explained below in an easy-to-understand manner.

Generally, a video signal for one frame consists of signals for two fields, an odd field and an even field.One field consists of 262.5H (however, H indicates the horizontal scanning period), so the odd field In the even field, there is a phase shift of 'AH.

Therefore, when recording the video signal for one field on each rotating track of the magnetic sheet, the video signal of the odd field is recorded on one track, the video signal of the even field is recorded on the other tracks, and so on. If even fields are mixed and recorded, and during playback, if the playback head is moved from the track where the odd field video signal is recorded to the track where the even field video signal is recorded, the above Because of the phase shift of 'AH, the reproduced image becomes discontinuous and skew occurs.

Note that related to this type of device, Japanese Patent Application Laid-open No. 5
No. 0-40021 can be mentioned, but the above-mentioned problem of skew that occurs during movement between trunks is not particularly taken into consideration.

[Purpose of the invention]

The purpose of the present invention is to record still images intermittently and continuously;
It is an object of the present invention to provide a still image recording and reproducing device that can prevent the occurrence of skew when moving between tracks when reproducing this image.

[Summary of the invention]

The feature of the present invention is to select one of the two field signals, odd number and even number, which constitute one frame of the recorded video signal, and to By recording only the field signals on each concentric track, even if the playback head is moved between tracks during playback, there will be no phase discontinuity in the playback image, and skew can be prevented. That's true.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, l is a video signal input terminal, 2 is a decoder,
3 and 5 are modulation circuits, 4 is a line sequential switch, 6 is a synchronization separation circuit, 7 is a recording gate control circuit, 8 is an addition circuit, 9 is a recording gate circuit, IO is a changeover switch, 11 is a magnetic head, and 12 is a a magnetic sheet, 13 a magnetic head feed circuit, 14 a motor, 15 a motor servo circuit, 16 a position detection magnet attached to a specific position on the magnetic sheet 12 to detect the rotational position of the sheet;
17 is a detection head placed near the magnetic sheet 12 and detects when the magnet 16 approaches; 20 is an amplifier; 21 and 22 are demodulation circuits; 25 and 26 are changeover switches, 28 is a synchronization circuit, 29 is an encoder, and 30 is a signal output terminal.

The operation of each part will be explained according to the flow of signals. During recording, a video signal input to input terminal 1 (obtained from a television, video tape recorder, etc.) is converted by decoder 2 into a luminance signal Y and two color difference signals (R-Y) and (B-Y). Ru. The luminance signal is subjected to, for example, FM modulation in the sub-modulation circuit 3, and the color difference signal is alternately switched for each IH by the line sequential switch 4 and made line sequential, and then, in the modulation circuit 5, it is subjected to, for example, FM modulation.
The signal is M-modulated and added to the modulated luminance signal in an adder circuit 8.

The added signal is made conductive only for the necessary recording period by the recording gate circuit 9, and is supplied to the fixed magnetic head 11 via the R side of the changeover switch 10, and the magnetic sheet rotates exactly once for one field of the video signal. It is recorded in 12.

The magnetic heald 11 is intermittently moved in the radial direction of the magnetic sheet 12 at the same pitch (the moving mechanism is not shown) in response to a signal from the head feed circuit 13 to form concentric recording tracks. The magnetic sheet 12 is rotationally driven by a motor 14, and a signal obtained by detecting a signal from a position detection magnet 16 indicating a reference position of the magnetic sheet 12 with a detection head 17 (this is called a TACH signal) and an image are detected. The motor servo circuit 15 to which the vertical synchronizing signal separated from the signal is supplied rotates exactly once in one vertical scanning period (one field period) of the video signal, and the vertical synchronizing signal is applied to a predetermined position of the magnetic sheet 12. Controlled to be recorded.

The recording gate circuit 9 is controlled by a signal from the recording gate control circuit 7 to which the synchronization signal of the video signal separated by the synchronization separation circuit 6 and the recording command signal input from the terminal 53 are input. The details will be described later.

Next, the playback operation will be explained. During playback, the selector switch 10 is switched from the terminal P side to the P side. The signal reproduced by the magnetic head 11 is amplified by the amplifier 20 via the P side of the changeover switch 10, and the luminance signal is amplified by the demodulation circuit 2.
1, and the color difference signal is demodulated by a demodulation circuit 22.

The demodulated luminance signal and color difference signal are transferred to the V2H delay line 23.2.
Switch 2 to switch between the signal that passes through 4 and the original signal that does not pass through.
5.26 alternately switches each field to prevent skew that occurs when a field recording signal is repeatedly reproduced.

Note that the alternate switching circuits for each field of the changeover switches 25 and 26 are not shown.

The luminance signal is supplied to an encoder 29, and the color difference signal is converted back to two consecutive color difference signals by a synchronization circuit 28, which is then supplied to an encoder 29. The encoder 29 converts the luminance signal and the color difference signal into a composite video signal and outputs it to the output terminal 30.

FIG. 2 is a block diagram showing details of the recording gate control circuit 7 in FIG. 1. In the same figure, 50 is a synchronization signal input terminal, and the composite synchronization signal separated from the input video signal in the synchronization separation circuit 6 of FIG.
The signal is supplied to the field identification circuit 51 via. The field identification circuit 51 is a circuit that mutually identifies two odd-numbered and even-numbered field signals that constitute one frame of video signal.

Field identification is a well-known fact that if the phase of one horizontal synchronizing signal, which is a vertical synchronizing signal, matches in the odd field period, the phase of the vertical synchronizing signal and the corresponding horizontal synchronizing signal differs by 〃H in the even field period. This can be easily done by taking advantage of the fact that 5
2 is an AND circuit, 53 is a recording command signal input terminal, 54 is a D-type flip-flop, 55 is an input terminal for a clock supplied as a TACH signal from the rotation detection head 17 of the magnetic sheet 12 shown in FIG. /N frequency divider circuit,
57 is an output terminal.

FIG. 3 is a waveform diagram of various signals in FIG. 2.

The operation will be explained with reference to FIGS. 2 and 3.

The field identification circuit 51 performs identification based on the operating principle described above, and outputs a high signal for an even field and a low signal for an odd field as a pulse that is inverted for each field as shown in FIG. 3(B). do. The field identification signal (B') from the identification circuit 51 is AND
The signal is supplied to the circuit 52 and is ANDed with the recording command signal (C) input from the terminal 53, and is supplied to the data input (D) terminal of the D type flip-flop 54. As already mentioned, the TACH signal (E) from the rotation detection head 17 of the magnetic sheet 12 is input to the clock input terminal 55 of the flip-flop 54, and this signal (E) is used as the data input signal of the flip-flop 54. It takes in the signal and outputs it as signal (F)1 to the Q terminal. flip flop 5
The output (F) of 4 is supplied to a frequency dividing circuit 56, and the recording gate control signal (F) 2 from its output terminal 57 controls the recording gate 9 of FIG.

In Figure 3, the TACH signal (E) is the vertical synchronization signal (
A) The rotation of the magnetic sheet 12 is controlled so that it occurs earlier in terms of phase. Recording command signal (C) is at time T
, -T0, the signal is high during this period, and the magnetic sheet 12 operates to record a video signal during this period. The AND output of the field identification signal (B) and the recording command signal (C) is taken into the flip-flop 54 at the timing of the TACH signal (E), and its Q
Since it is output to the terminal, the output waveform is as shown in (F)1.

Waveform (F) 1 corresponds to the recording gate control signal when the frequency dividing circuit 56 is not provided, and when the gate control signal is high, the recording gate 9 is turned on and current is supplied to the magnetic head 11.

In the example shown in FIG. 3, the control signal (
t")+ occurs. Therefore, time T.

During the period ~T2, one field of signal is recorded on a certain track, the magnetic head 11 is moved to the next track during the period from time T2 to T, and during the next period from T3 to T4, one field of signal is recorded on the moved track. Record the signal.

Thereafter, this operation is repeated to record odd field signals concentrically on the magnetic sheet 12 every other field.

FIG. 3(F)z shows the recording gate control signal when the frequency dividing circuit 56 of FIG. 2 is used. By setting the frequency division ratio to an appropriate value N, recording and track movement can be controlled. Odd field signals can be recorded intermittently, alternately and repeatedly every N frames.

FIG. 4 shows a recorded pattern on the magnetic sheet 12 recorded according to the above operation.

In FIG. 4, Tri, Tr2. Since Tr3 indicates a recording track (magnetic sheath) 12 rotates once in one field (262.5H in Japanese TV signals) period, the recording end position is at the center position i! of one horizontal opening signal period. (
%H position), but since only the odd fields are selectively recorded, the horizontal synchronizing signals are recorded so as to line up in the radial direction of the magnetic sheet 12.

Note that, as described above, the vertical synchronization signals are also arranged in the same manner as the horizontal synchronization signals.

Therefore, even if the recording track Tri is moved to the recording track Tr2 during reproduction, the continuity of the horizontal synchronizing signal is maintained, and no skinny occurs in the reproduced image.

Near the recording end point, the horizontal synchronization signal is at %H intervals,
Since the changeover switches 25 and 26 in Fig. 1 are controlled to insert the H delay line for each field using the TACH signal, the continuity of the horizontal synchronization signal is ensured no matter where on the playback track the track is moved. is maintained.

Regarding the color difference signal, skinny is the same as the luminance signal, but in the case of color difference line sequential, the type is different for each lH, so even if horizontal synchronization signals are lined up in adjacent tracks, the type of color difference signal does not necessarily match. . If the color difference signals between adjacent tracks do not match, the line-sequential continuity will not be maintained when the tracks are advanced, and the color signals will be misjudged and the colors will change.One frame is 525H, so two frames (4 fields) ), therefore, in the case of intermittent recording, if recording is performed every four fields, the color difference signals will line up on adjacent tracks. Therefore, when recording intermittently, it is preferable to record at intervals of an integral multiple of 4 fields. FIG. 4 also shows the arrangement of color signals at this time.

〔Effect of the invention〕

According to the present invention, in a still image recording and reproducing device, it is possible to eliminate the occurrence of skew in the reproduced image when the magnetic head moves between tracks, so a high-quality reproduced image can be obtained, and there is a significant effect on performance improvement. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing details of the recording gate control circuit 7 in FIG. 1, and FIG. 3 is a waveform diagram of various signals in FIG. FIG. 4 is an explanatory diagram showing an example of a recording pattern on a magnetic sheet. Explanation of symbols 7... Recording gate control circuit, 9... Recording gate circuit, 11... Magnetic head, 12... Magnetic sheet, 51
...Field identification circuit agent Patent attorney Akira Namiki

Claims (1)

[Claims] 1. Using a magnetic head movable in the radial direction of a rotating recording medium that rotates once per vertical scanning period (one field period) of an input video signal, In a still image recording and reproducing apparatus that concentrically records the video signal as a still image and reproduces the still image, an identification means for respectively identifying two odd-numbered and even-numbered field periods constituting one frame period of the input video signal; , means for selecting a specific field period of either an odd number or an even number identified by the identification means when a recording command is input; means for recording on a medium;
1. A still image recording and reproducing apparatus characterized in that video signals in a specific field period, either an even number or an odd number, are recorded concentrically at a field ratio.