JPH0484583A - Image signal 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 Industrial Application] The present invention relates to an image signal reproducing device for reproducing image signals recorded on a recording medium.

[Prior Art] Conventionally, there are video recorders and still video cameras as systems for recording image signals on a magnetic tape or magnetic disk as a recording medium and reproducing the recorded image signals from the recording medium.

In the above system, time axis fluctuations occur in the reproduced image signal due to fluctuations in the relative speed between the recording medium and the reproduction head that occur during reproduction, and the image quality deteriorates. T B C (T
ime BaseCorrection).

For example, a video tape recorder uses a PLL (Pha
A sampling link clock that is synchronized with the horizontal synchronization signal in the reproduced image signal and has the same time axis fluctuation as that of the reproduced image signal is formed using a circuit such as scl, locked loop), and is reproduced using the sample link clock. After digitizing the image signal and temporarily storing it in a memory etc., the time f
By reading out the digital image signal stored in the memory in synchronization with an accurate lock signal with no fJT axis fluctuations and converting it back into an analog image signal, the time axis that occurs in the reproduced image signal during reproduction can be read out. Some method is used to remove fluctuations.

In addition, a still video camera does not display other information corresponding to the image signal (field/frame recording discrimination information, date information, etc.) and uses a single frequency signal with a frequency of 13 fH (fH is the horizontal synchronization frequency) to transmit ID data. DPS as a carrier
K (Diffcrential Phase 5hif
t keying) to form an ID signal, and this ID signal is recorded on a recording medium together with an image signal. During playback, a PLL circuit or the like modulates the carrier frequency signal of the ID signal (i.e. A sample link clock is formed that is synchronized with a single frequency signal of 13 f H (a single frequency signal with a frequency of 13 f H) and generates the same time axis fluctuation as the reproduced image signal, and the reproduced image signal is digitized using the sample link clock. After that, the digital image signal stored in the memory is read out in synchronization with an accurate lock signal with no % axis fluctuation, and then converted into an analog image signal again. Methods have been considered to remove time axis fluctuations that occur in reproduced image signals during reproduction.

[Problems to be Solved by the Invention] By the way, in the above-mentioned still video camera, when separating the ID signal from the reproduction signal reproduced from the recording medium during reproduction, the carrier frequency component (13f1
1) It is customary to use a bandpass filter (BPF) having a passband centered on the filter.

However, since the ID signal has a frequency or a phase inversion of the carrier signal of l 3 f 11 depending on the content of the ID data, the phase inversion part of the carrier signal is 13f.
It has a frequency component of H/2, and as described above, P
The amplitude and phase of the phase-inverted portion of the ID signal separated using F vary greatly.

When TBC processing is performed using an ID signal in which the amplitude and phase of the phase inversion part fluctuate greatly as described in 1-1, the ID signal (the time that occurs in the image signal during sketching) is Since there is a time axis variation that is different from the axis variation, there is a problem that accurate TBC processing cannot be performed.

The present invention solves the above-mentioned problems, and provides an image signal reproducing device that can accurately remove time axis fluctuations that occur in reproduced image signals during reproduction, and obtain reproduced images without deterioration due to time axis fluctuations. Let's call it 11 things.

[Means for Solving the Invention] The image signal reproducing device of the present invention records both an image signal and an information signal formed by modulating a carrier wave signal using data representing information corresponding to the image signal. a device for reproducing the image signal from a recording medium that is
a reproducing means for reproducing the image signal and the information signal together from the recording medium and separating and outputting the reproduced image signal and the information signal; inputting the information signal output from the reproducing means; gate means for gating and outputting the information signal for a predetermined period synchronized with a horizontal synchronization signal; clock signal forming means for forming a clock signal phase-synchronized with a carrier wave signal of the information signal outputted from the gate means; The apparatus further includes a time axis variation correcting means for correcting time axis variation with respect to the image signal outputted from the reproduction means using the clock signal formed by the clock signal forming means.

[Function] According to the dual configuration, it becomes possible to accurately and stably correct the time axis fluctuation occurring in the image signal reproduced from the recording medium.

[Example] Hereinafter, the present invention will be explained using examples of the present invention.

FIG. 1 is a block diagram showing a schematic configuration of a playback system of a still video camera as an embodiment of the present invention.

In FIG. 1, during reproduction, a magnetic disk l is rotated by a motor 2 at a predetermined number of rotations, and a head moving mechanism (not shown) moves a magnetic head 3 to an arbitrary track position on the magnetic disk l. The signals recorded on the tracks of the magnetic disk 1- are reproduced by the spatula 1<3 and supplied to the reproduction amplifier 4.

Then, the regenerative signal amplified by the regenerative amplifier 4 is BPF
5. The ID signal is supplied to the luminance/chrominance signal separation circuit 6, and the BPF 5 separates the ID signal from the reproduced word supplied from the reproduction amplifier 4, and the luminance/color signal separation circuit 6 separates the ID signal from the FM-modulated luminance signal. The FM modulated color difference line sequential signal is separated, the FM modulated luminance signal is demodulated in the brightness FM demodulator 7 and then supplied to the A/D converter 8, and the FM modulated color difference line sequential signal is demodulated in the color FM demodulator 7. After being demodulated at 9, the A/D
is supplied to the converter lO.

Then, the ID signal separated in the BPF 5 is supplied to the PLL circuit 14 after passing through a gate circuit 11 whose opening/closing is controlled by a gate pulse output from a mono multi-high inflator 13, which will be described later. A sample link clock signal phase-synchronized with the ID signal supplied from the gate circuit 11 is generated and supplied to the A/D converter 8, memory 16, and frequency divider 15. The printer clock signal is A
/D converter 10 and memory 17.

After the A/D converter 8 digitizes the luminance signal supplied from the luminance FM demodulator 7 in synchronization with the sunblink clock signal supplied from the PLL circuit 14, the formed digital luminance signal is It is stored in the memory 16 in synchronization with the sampling clock signal, and the A/D
The converter 10 digitizes the color difference line sequential signal supplied from the color FM demodulator 9 in synchronization with the sunblink clock signal supplied from the PLL circuit 14 and divided into 1/4 by the frequency divider 15. , the formed digital color difference line sequential signal is stored in the memory 17 in synchronization with the sunblink clock signal.

In the following manner, the luminance signal and color difference line sequential signal reproduced from the magnetic disk l are digitized in synchronization with a sample link clock signal whose phase is synchronized with the ID signal similarly reproduced from the magnetic disk l, After storing in memories 16 and 17, clock signal generator 1 is stored in memory 16.
A digital luminance signal Y is read from the memory 16 in synchronization with the clock signal and is supplied to the D/A converter 20.

Further, a clock signal generated by a clock signal generator 18 and divided into 1/4 by a frequency divider 19 is supplied to the memory 17, and the memory 17 is supplied with a clock signal whose frequency is divided by 1/4 by a frequency divider 19.
By reading out and synchronizing the digital color difference line sequential signals stored in 7, the digital color difference signal R-Y is sent to the D/A converter 21, and the digital color difference signal B-Y is sent to the D/A converter 21.
The signal is supplied to the A converter 22.

Then, the digital luminance signal Y read out from the memory 16 in the D/A converters 20, 21, and 22, and the memory 1
Digital color difference signals R-Y, B-Y read out from 7
By analogizing each of the D/A converters 20,
21.22 is the luminance signal Y9 from which time axis fluctuations have been removed.
Color signals R-Y and B-Y are output.

FIG. 2 is a timing chart showing signal waveforms at various parts of the device shown in FIG.

The opening/closing operation of the gate circuit 11 shown in FIG. 1 to the case 1 will be described below using the timing chart shown in FIG. 2.

During recording, the ID signal as shown in FIG. 2(a) is multiplexed with the image signal and recorded on the magnetic disk, and during reproduction, the ID signal is reproduced together with the image signal by the magnetic head 3 shown in FIG. 1.
The signal waveform of the signal is as shown in FIG. 2(b).

The ID signal reproduced by the magnetic head 3 is separated from the image signal via the BPF 5 shown in FIG.
The signal waveform becomes as shown in FIG. 2(C).

Assuming that the phase of the ID signal is reversed at point A in the figure, as shown in FIG. 2(a), depending on the content of the corresponding information data, the reproduced I output from the BPF 5 in FIG.
In the D signal, fluctuations in signal amplitude and phase occur in the range indicated by B in FIG. 2(C).

Then, when a reproduction ID signal as shown in FIG. 2(C) is supplied to the PLL circuit 14 in FIG. 1 and TBC processing is performed,
Even if no time axis fluctuation occurs in the image signal during reproduction, the PLL circuit 14 converts the amplitude and phase fluctuations of the signal occurring during the period indicated by B of the reproduction ID signal into the time axis that occurred during reproduction. Since it is erroneously detected as a fluctuation, incorrect time axis correction processing will be performed. Therefore, in the embodiment shown in FIG. 1, the synchronization signal separation circuit 12 separates the horizontal synchronization signal Hs (see FIG. 2(d)) from the reproduced luminance signal output from the luminance FM demodulator 7. By supplying the signal to the multivibrator 13, a gate pulse Gp as shown in FIG. 2(e) is generated from the monomultivibrator 13 and is supplied to the gate circuit 11.

The gate circuit 11 is connected to the mono multivibrator 1.
The gate is configured to close during the period when the gate pulse Gp supplied from 3 is at a high level (H in the figure).
From the gate circuit 11, as shown in FIG. 2(f), the B
In the reproduction ID signal output from PF5, the BPF
5, a gated reproduction ID signal is outputted every IH (H is one horizontal opening period) during which fluctuations in the amplitude and phase of the signal are occurring, and is supplied to the PLL circuit 14 at the subsequent stage. Therefore, the PLL circuit 14 outputs the playback I during playback.
Since a sampling clock signal is generated that follows the time axis fluctuation occurring in the D signal, it becomes possible to perform accurate and stable correction of the time axis fluctuation.

FIG. 3 is a block diagram showing a schematic configuration of a playback system of a still video camera as another embodiment of the present invention.

In FIG. 3, components similar to those shown in FIG. 1 are given the same reference numerals, and detailed explanations will be omitted.

In the embodiment shown in FIG. 3, the synchronization signal separation circuit 23 separates the horizontal synchronization signal Hs and the vertical synchronization signal Vs from the reproduced luminance signal output from the luminance FM demodulator 7, and the horizontal synchronization signal Hs is further frequency-divided. After the frequency is divided into 172 by the converter 24, the frequency is divided into 172 by supplying it to the mono multivibrator 25.
, from the mono multivibrator 25, a gate pulse Gp' having the same pulse waveform as the gate pulse Gp output from the mono multivibrator 13 in FIG. period) and is supplied to the gate circuit 11.

The gate circuit 11 is connected to the mono multivibrator 1.
In order to close the gate while the gate pulse Gp supplied from the circuit 3 is at a high level, the gate circuit 11 outputs the signal B from the gate circuit 11.
In the reproduction ID signal output from PF5, the BPF
5, the period during which signal amplitude and phase fluctuations occur is gated every 2H or 4H.
Since the signal is output and supplied to the PLL circuit 14 at the subsequent stage, the PLL circuit 14 generates a sampling clock signal that follows the time axis fluctuations occurring in the reproduction ID signal during reproduction, so it is accurate and stable. This makes it possible to correct the time axis fluctuations that occur.

In the embodiment shown in FIG. 3, compared to the embodiment shown in FIG.
It is necessary to perform BC processing.

FIG. 4 is a block diagram showing a schematic configuration of a playback system of a still video camera as another embodiment of the present invention.

Incidentally, in FIG. 4, components similar to those shown in FIGS. 1 and 3 are numbered and detailed explanations will be omitted.

In the embodiment shown in FIG. 4, a horizontal synchronizing signal Hs and a vertical synchronizing signal Vs are separated from the reproduced luminance signal output from the luminance FM demodulator 7 by a synchronizing signal separation circuit 23, and a monomultibilalator 26 and an ID signal are separated. , demodulator 27, and shift register 28.

Further, the ID signal demodulator 27 is supplied with a reproduction signal from the reproduction amplifier 4, and the ID signal demodulator 27 separates the ID signal from the reproduction signal and restores the ID data by performing DPSK demodulation. The signal is supplied to the shift register 28.

Then, the shift register 28 and the ID signal demodulator 27
A reversal instruction that indicates the position at which the ID data supplied by the ID data is sequentially shifted and the content of the ID data changes from "0" to "i" or from "1" to "0", that is, the timing at which the phase of the ID signal is reversed. The signal is applied to a mono multiviralator 26.

Incidentally, only when an inversion instruction signal is supplied from the shift register 28 from the mono-multiviralator 26, a gate pulse having the same pulse waveform as the gate pulse Gp output from the mono-multiviralator 13 in FIG. Gp
'' is generated and supplied to the gate circuit 11.

Then, the gate circuit 11
During the period when the gate pulse Gp'' supplied from circuit 3 is at a high level, circuits 1 to 1 are closed, so that the reproduced ID signal outputted from circuit 11 from circuit 11 passes through BPF 5. The gated reproduction ID signal is output only during the period in which fluctuations in signal amplitude and phase are occurring, and is supplied to the PLL circuit 14 at the subsequent stage.
Since the L circuit 14 generates a sunblink clock signal that follows the time axis fluctuation occurring in the reproduction ID signal during playback, it becomes possible to perform accurate and stable correction of the time axis fluctuation. .

Note that, compared to the embodiments shown in FIGS. 1 or 3, the embodiment shown in FIG. Since it is gated by the 1~ circuit, efficient and highly accurate TBC processing can be performed.

Furthermore, in the embodiments shown in FIGS. 1, 3, and 4, after the reproduced image signal is digitized in synchronization with a sunblink clock that follows the time axis fluctuation occurring in the image signal during reproduction, , is stored once in a memory, etc., read out from the memory in synchronization with an accurate lock signal, and then converted back to an analog signal to correct time axis fluctuations.
It may also be configured to perform in an analog manner using a delay element such as a multiplexed device.

[Effects of the Invention] As explained above, according to the present invention, the conventional problems are solved, the time axis fluctuations that occur in the reproduced image signal during reproduction are accurately removed, and the deterioration due to the time axis fluctuations is reduced. It becomes possible to provide an image signal reproducing device that can obtain reproduced image signals that are not available before.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a playback system of a still video camera as an embodiment of the present invention. FIG. 2 is a timing chart showing signal waveforms at each part of the device shown in FIG. FIGS. 3 and 4 are block diagrams showing a schematic configuration of a playback system of a still video camera as another embodiment of the present invention. 5...Bant pass filter 8.10...A/D converter 11...Gate circuit 12...Synchronization signal separation circuit 13...Mono multi high inflator 14...PLL circuit 15.19. ...Frequency divider 16,17...Memory 18...Clock signal generator 20-22...D/A converter

Claims (1)

[Claims] The image signal is obtained from a recording medium on which both the image signal and an information signal formed by modulating a carrier wave signal using data representing information corresponding to the image signal are recorded. A reproducing device, comprising: reproducing means for reproducing both the image signal and the information signal from the recording medium, and separating and outputting the reproduced image signal and information signal; and information output from the reproducing means. gating means for inputting a signal, gating the inputted information signal for a predetermined period synchronized with a horizontal synchronizing signal, and outputting the gated signal; and forming a clock signal phase-synchronized with a carrier wave signal of the information signal outputted from the gating means. A clock signal forming means; and a time axis variation correcting means for correcting a time axis variation with respect to an image signal output from the reproduction means using the clock signal formed by the clock signal forming means. An image signal reproducing device characterized by: