JPH04139981A - Picture signal processing unit - Google Patents

Abstract

PURPOSE:To output a picture signal without causing any jitter or the like by replacing a synchronizing signal in a 1st period designated by a period designation signal generated from a signal generating means among synchronizing signals in the picture signal into a synchronizing signal generated from the signal generating means. CONSTITUTION:A synchronizing signal replacement circuit 6 replaces a synchronizing signal in a reproduced luminance signal fed from an FM demodulator 5 into replacement synchronizing signal (d) in response to the applied replacement period designation signal (c). Thus, the synchronizing signal replacement circuit 6 outputs a signal and is fed to a 1/2H delay line 10 and a changeover switch 11 in a skew compensation circuit 9. In this case, a luminance signal whose synchronizing signal is replaced outputted from the synchronizing signal replacement circuit 6 is delayed by the 1/2 H delay line 10 and fed to the changeover switch 11 and the luminance signal not causing jitter and fluctuation is outputted by controlling the changeover switch 11 with a switch changeover control signal (g).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image signal processing device that processes image signals.

[Conventional technology]

2. Description of the Related Art Conventionally, as an image signal processing device for processing image signals, there is an electronic still video system that records still image signals on a recording medium such as a magnetic disk and reproduces the still image signals recorded on the recording medium.

In the electronic still video system described above, a still image signal for one field is recorded on one track on a magnetic disk, and by repeatedly reproducing one track, the reproduced still image signal for one field can be reproduced. So-called field reproduction is performed in which a still image signal for one frame is formed from a signal.

However, during the field playback described above, the horizontal synchronization signal is detected at the PG point on the magnetic disk, that is, at the position 7H±2H (H is one horizontal synchronization period) before the vertical synchronization signal recorded on the track on the magnetic disk. A discontinuity occurs in the phase, and in order to compensate for this discontinuity in phase, the still image signal for one field reproduced from the magnetic disk is delayed by %I] every one field period, which is a so-called skew. Compensation was being processed.

Note that there are the following three types of conventional skew compensation processing methods.

First, the first method is to combine the reproduced still image signal with no 'AH delay without replacing the composite synchronization signal (horizontal synchronization signal and vertical synchronization signal) in the reproduced still image signal,
This is a method of performing skew compensation processing by alternately outputting a reproduced still image signal delayed by 2H every one field period.

A second method is to perform skew compensation processing by replacing the composite synchronization signal in the reproduced still image signal with a composite synchronization signal without phase discontinuity generated by a synchronization signal generator or the like.

Furthermore, as a third method, the PG in the reproduced still image signal
Skew compensation processing is performed by replacing the synchronization signal in the period including the point and vertical synchronization signal (approximately equivalent to the vertical blanking period) with a synchronization signal without phase discontinuity generated by a synchronization signal generator, etc. .

[Problem that the invention is trying to solve]

However, the conventional method described above has the following problems.

In other words, since the first method does not replace the composite synchronization signal in the still image signal, there is a discontinuity in the phase of the synchronization signal at the switching part between the odd field still image signal and the even field still image signal. Therefore, for example, when counting the number of synchronization signals and generating other timing signals, there is a risk that another timing signal may be generated at an incorrect timing.

Furthermore, in the second method, the composite synchronization signal in the reproduced still image signal is replaced with a composite synchronization signal generated from a synchronization signal generator, etc., so the image part and the composite synchronization signal part in the reproduced still image signal are replaced. The phase relationship between the images is disrupted and jitter occurs in the reproduced still image.

Furthermore, the third method replaces the synchronization signal in the period including the PG point and vertical synchronization signal in the reproduced still image signal with a synchronization signal generated from a synchronization signal generator, etc. During the corresponding period, the phase relationship between the synchronization signal part and the image part is maintained, and no jitter occurs in the horizontal direction of the screen, but a shift occurs in the vertical direction of the screen, causing fluctuation. Put it away.

SUMMARY OF THE INVENTION Therefore, the present invention provides an image signal processing device that can solve the two problems, maintain the phase continuity of a synchronization signal in an image signal, and output an image signal free from jitter. aim at something.

[Means to solve the problem]

The image signal processing device of the present invention is a device for processing an image signal composed of a signal of an odd field) and a signal of an even field, and is synchronized with a synchronization signal in the image signal, and a period designation signal that designates a first period including a switching point, a signal generating means that generates a synchronization signal that is phase-synchronized with a synchronization signal other than the first period in the image signal; Replacement means for replacing, among the synchronization signals, a synchronization signal during a first period specified by the period designation signal generated by the signal generation means with the synchronization signal generated by the signal generation means. .

[Effect]

According to the above-described configuration, it is possible to maintain the phase continuity of the synchronizing signal in the image signal and output an image signal free of jitter or the like.

〔Example〕

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

FIG. 1 is a diagram showing a schematic configuration of a playback device for an electronic still video system to which the present invention is applied, as a first embodiment of the present invention.

In the figure, 1 is a magnetic head for reproducing still image signals recorded on a magnetic disk (not shown), 2 is a preamplifier for amplifying the signal reproduced by the magnetic head, and 3 is the preamplifier. 2 is an FM modulated brightness signal separation circuit that separates the FM modulated brightness signal from the signal outputted from the signal outputted from the FM modulated brightness signal separation circuit 3; 4 is an equalizer circuit that compensates for the frequency characteristics of the FM modulated brightness signal separated in the FM modulated brightness signal separation circuit 3; FM output from the equalizer circuit 4
An FM demodulator 6 for FM demodulating a modulated luminance signal is a FM demodulator 6 which converts a synchronization signal in the luminance signal output from the FM demodulator 5 to a synchronization signal output from a synchronization signal generator 8, which will be described later. 7 is a sync signal separation circuit that separates a sync signal from the luminance signal output from the FM demodulator 5; 8 is a sync signal separation circuit that separates the sync signal from the sync signal separated in the FM demodulator 5; Attached is a synchronous signal generator that generates the synchronous signal and other various timing signals that are exchanged in the exchange circuit 6, and 9 is a synchronous signal generator that generates the input signal to y2I.
] Delaying I/2H delay line 10 and the V2II delay line 1
A signal delayed from 0 and a signal not delayed are set to 1
A skew compensation circuit is constituted by a changeover switch 11 which is switched every field period, and 12 is an output terminal for a luminance signal.

The operation of the configuration shown in FIG. 1 will be explained below using the timing charts shown in FIGS. 2 and 3.

Incidentally, FIG. 2 shows a case where the luminance signal outputted from the output terminal is switched from an odd field to an even field.
Further, FIG. 3 shows a case where the field is switched from an even field to an odd field.

In FIG. 1, a still image signal reproduced from a magnetic disk (not shown) by a magnetic head 1 is amplified by a preamplifier 2 and then supplied to an FM modulated luminance signal separation circuit 3.

Then, in the FM modulated luminance signal separation circuit 3, the FM
After the modulated luminance signal is separated and the frequency characteristics are compensated for in the equalizer circuit 4, the modulated luminance signal is
By performing the M demodulation, the FM demodulator 5 outputs a reproduced luminance signal as shown in FIGS. Ru.

In synchronization signal separation circuit 7, a second
A synchronizing signal as shown in FIG.

In the synchronization signal generator 8, the synchronization signal separation circuit 7
Based on the synchronization signal supplied from the synchronization signal switching circuit 6, the synchronization signal switching circuit 6 generates a switching period designation signal C (see FIGS. 2 and 3 C), which specifies the switching period. A switching synchronization signal d (see FIGS. 2 and 3 g)) that is switched in the switching circuit 6 (see FIGS. 2 and 3 g), and a switch switching control signal that controls the switching operation of the switching switch 11 in the skew compensation circuit 9. g (see FIGS. 2 and 3 g)).

As shown in FIGS. 2 and 3, when the switching period designation signal C is at a high level, the sync signal indicates the switching period, and when the switch switching control signal g is at a high level. During the low level period, the selector switch 11 selects the delayed luminance signal (see FIGS. 2 and 3 f) output from each delay line 10. 11 or the luminance signal not delayed by the V2H delay line 10 (see FIGS. 2 and 3e)).

In addition, the rising timing of the switching period designation signal C is 1 at the start point of the vertical synchronization signal (point G in FIG. 2b) and FIG. 3b) for both odd and even fields.
1, 5 before T-T, and the falling timing is 3H before the start point of the vertical synchronization signal (point B in Fig. 2b) when switching from an odd field to an even field.
When switching from an even field to an odd field, 2.5H before the start point of the vertical synchronization signal (the third
Point C) in Figure b).

Further, the above-mentioned switching synchronization signal d is output only during the period when the above-mentioned switching period designation signal C is at a high level, and its phase is 12H before the start point of the vertical synchronization signal (second
(see Figures 1 and 3).

Further, the switch switching control signal g switches from high level to low level when switching from an odd field to an even field, and the switching retiming occurs 6H after the start point of the vertical synchronization signal (Fig. 2b). When switching from an even field to an odd field, it switches from low level to high level, and the switching timing is 2H before the start point of the vertical synchronization signal (point F).
This is point D in Figure 3b).

As described above, the switch switching period designation signal C1 generated by the synchronization signal generator 8 is sent to the switching circuit 6, and the switch switching control signal g is sent to the switching circuit 6. The signal is supplied to the changeover switch 11.

Then, in the synchronization signal switching circuit 6, the synchronization signal in the reproduced luminance signal supplied from the FM demodulator 5 in the previous stage is switched to the synchronization signal d in accordance with the supplied switching period designation signal C. By changing the attachment, the one with the synchronization signal can be replaced with the circuit 6.
The signal shown in e) of Figs. 2 and 3 is output from the
It is supplied to the %H delay line 10 and changeover switch 11 in the skew compensation circuit 9.

The luminance signal with the synchronizing signal output from the synchronizing signal switching circuit 6 is delayed by the 'AH delay line IO, and is switched as shown in f) in FIGS. 2 and 3. By controlling the changeover switch 11 with the switch changeover control signal g, the changeover control signal g is supplied to the switch 11, so that when switching from an odd field to an even field as shown in h) in FIGS. 2 and 3, When switching from to an odd field, it becomes possible to output a luminance signal in which no phase discontinuity occurs in the synchronizing signal, and no jitter or fluctuation occurs in both the horizontal and vertical directions.

In the first embodiment, the case of field playback in the playback device of an electronic still video system has been explained above, but even during frame playback in which two tracks on a magnetic disk are played back alternately, there is no difference in the recording time. Due to differences in the switching timing of the magnetic head during playback, uneven rotation of the magnetic disk, etc., the phase of the synchronization signal may become discontinuous when switching from an odd field to an even field or from an even field to an even field. , the same problem as the above-mentioned field playback may occur.

Therefore, as shown in Figure 4, by replacing the sync signal during the period in which the phase discontinuity of the sync signal occurs with the sync signal in which the phase discontinuity does not occur, the same effect as during field playback can be obtained. You will be able to obtain

In FIG. 4, the same components as in FIG. 1 are given the same numbers, and detailed explanations will be omitted.

FIG. 4 is a diagram showing a schematic configuration of a reproducing apparatus for an electronic still video system to which the present invention is applied as a second embodiment of the present invention. The signals reproduced by the switch 14 are alternately switched for each field period and supplied to the preamplifier 2.The following operation is the same as that of the embodiment shown in Fig. 1, but when reproducing the frame, Since there is no need to perform skew compensation, the skew compensation circuit 9 in FIG. has been done.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide an image signal processing device that can maintain the phase continuity of a synchronizing signal in an image signal and output an image signal free from jitter or the like. You will be able to do this.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a playback device for an electronic still video system to which the present invention is applied as a first embodiment of the present invention. 2 and 3 are timing charts showing signal waveforms at various parts in FIG. 1 in order to explain the operation of the embodiment shown in FIG. 1. FIG. 4 is a diagram showing a schematic configuration of a reproducing apparatus for an electronic still video system to which the present invention is applied as a second embodiment of the present invention. 1... Magnetic head 2... Preamplifier 3... FM modulation brightness signal separation circuit 4... Equalizer circuit 5... FM demodulator 6... Replacement circuit with synchronization signal 7... Synchronization signal Separation circuit 8... Synchronous signal generator 9... Skew compensation circuit lO... y2H delay line 11... Changeover switch 12... Output terminal

Claims (1)

[Scope of Claims] A device for processing an image signal composed of an odd field signal and an even field signal, comprising: a switching point between the odd field and the even field in synchronization with a synchronization signal in the image signal; a period designation signal that specifies a first period including a first period, a signal generating means for generating a synchronization signal that is phase-synchronized with a synchronization signal other than the first period in the image signal, and ,
Image signal processing characterized by comprising: replacement means for replacing a synchronization signal during a first period designated by a period designation signal generated by the signal generation means with a synchronization signal generated by the signal generation means. Device.