JPS62169595A - Picture reproducing device - Google Patents

Abstract

PURPOSE:To prevent flicker with a simplified constitution by applying 0.5H signal delay converting a field signal into a frame signal in the state of FM modulation signals of luminance and chrominance signals subjected to frequency division multiplex. CONSTITUTION:A delay circuit 13 retarding a multiplex FM signal reproduced from a recording medium 1 by 0.5H and a switching circuit 14 outputting switchingly a multiplex FM signal retarded by the said delay circuit and a multiplex FM signal reproduced from the recording medium and not retarded in the field period are provided. The multiplex FM signal being the output of the switching circuit 14 is separated into a luminance signal and a chrominance signal component, they are FM- demodulated respectively, and R-Y signal and a B-Y signal being the result of simultaneous processing of the demodulated luminance signal and the demodulated line sequential signal are inputted to a signal synthesis circuit such as an encoder circuit 12 or the like. Since the delay of 0.5H to convert the field signal into the frame signal is processed in the stage of the multiplex FM signal in the titled device, the delay circuit and the switching circuit are enough for one system and no gain difference of the luminance signal and the line sequential signal is caused between the signals retarded by 0.5H and the signal not retarded and a color still picture without flicker is reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reproducing device that repeatedly reproduces the same field, for example, to obtain a still image.

[Prior Art] Recently, electronic cameras, video floppy devices, and the like have been proposed as recording devices for video still image signals. These devices sequentially concentrically record multiple fields of color video signals corresponding to multiple color still images on a rotating magnetic sheet, and the recorded video signal consists of, for example, a luminance signal and a color signal. The signal is FM modulated and frequency division multiplexed, and the color signal is a line sequential signal in which two color difference signals, RY and BY signals, are alternately switched every horizontal period.

When recording such a color video signal, so-called "field recording" is sometimes performed in which only one of odd or even fields constituting one frame is recorded on one track.

In order to reproduce such a recorded field video signal and display it on a video monitor, the field video signal must be converted into a frame video. Conventionally, as such a reproducing device, for example, Japanese Patent Application Laid-Open No. 58-3338
7 and Japanese Patent Laid-Open No. 59-125184 have been proposed.

FIG. 2 is a schematic configuration diagram showing an example of such a conventional playback device, in which a plurality of field color still image video signals are arranged to form a plurality of concentric recording tracks on a rotating magnetic sheet (1). recorded magnetically. Then, any one circular recording track contains a luminance signal and an RY signal (R is a red signal).

Line sequential signals of two color difference signals, Y is a luminance signal) and B-Y signal (B is a blue signal) are FM modulated and frequency division multiplexed, and this multiplexed FM signal is transmitted over one field period. minutes are magnetically recorded. The rotating magnetic sheet (1) is driven to rotate at a field period of, for example, 60 Hz. The reproducing head (2) repeatedly reproduces the multiplexed FM signal from the single recording track. The FM modulation signal of the luminance signal extracted by the first filter circuit (3) which selects and outputs only the FM modulation signal of the luminance signal from the reproduced multiplex FM signal is sent to the first FM demodulation circuit (
4). In addition, a second FM signal that selects and outputs only the FM modulation signal of the line sequential signal from the reproduced multiplex FM signal is used.
FM of the line sequential signal extracted by the filter circuit (5) of
The modulated signal is supplied to a second FM demodulation circuit (6). At this time, the luminance signal for one field period is repeatedly obtained at the output of the first FM demodulation circuit (4), and the R-Y signal and the B- A signal for one field period of a line sequential signal in which the Y signal appears alternately every horizontal period is repeatedly obtained. The first FM demodulation circuit (4
) is supplied to one fixed contact (7a) of the first changeover switch (7), and the luminance signal is supplied to the first changeover switch (7) via a 0.5H (0.5 horizontal period) delay circuit (8). The movable contact (7c) of the first changeover switch (7) is connected to the luminance signal input terminal of the encoder circuit (12). R-Y signal and B of the output of the second FM demodulation circuit (6)
The line sequential signal of the -Y signal is supplied to one fixed contact (9a) of the second changeover switch (9), and this line sequential signal is passed through the 0.5H delay circuit (10) to the second changeover switch (9). 9) to the other fixed contact (9b), and the movable contact (9c) of the second changeover switch (9) to the synchronization circuit (
Connect to the input of 11). The synchronization circuit (11) synchronizes the line-sequential signals of the R-Y signal and the B-Y signal input through the movable contact (9c) of the second changeover switch (9), and converts them into the R-Y signal and the B-Y signal. The B-Y signal is output independently, and the R-Y signal input terminal of the encoder circuit (12) is connected to the B-
Supplied to each Y signal input terminal. Encoder circuit (
12) is designed to synthesize and output a composite video signal from the input luminance signal, RY signal, and BY signal. By the way, switching control of the first changeover switch (7) and the second changeover switch (9) is performed in conjunction with each other in a field period.

That is, the movable contacts (7c) and (9c) are repeatedly and alternately connected to one fixed contact (7a) and (9a) and the other fixed contact (7b) and (9b) in sequence for each field.

In this case, in the first field, the movable contacts (7c) and (9c) of the first and second changeover switches (7) and (9) are connected to one fixed contact (7a) and (9a), respectively. . At this time, the luminance signal output from the first demodulation circuit (4) is transmitted to the encoder circuit (1) via the first switch circuit (7).
2). Also at this time, the second demodulation circuit (6)
The line-sequential signals output from
The Y signals are each supplied to an encoder circuit (12),
The encoder circuit (12) synthesizes and outputs the composite signal, and when this is supplied to a monitor, a color image of the first field can be obtained.

Next, in the case of the second field, the movable contacts (7C) and (
9c) are connected to the other fixed contacts (7b) and (9b), respectively. At this time, since the m-degree signal supplied to the encoder circuit (12) is first delayed by 0.5H by the delay circuit (8), the first field and the second field are in an interlacing relationship. Also, at this time, since the line sequential signal obtained at the movable contact (9C) of the second changeover switch (9) is delayed by 0.5H in the delay circuit (10), the R-Y of the output of the synchronization circuit (11) Both signal and B-Y signal are 0.5
This will result in an H delay. These are the encoder circuits (
12), a second field signal is obtained which forms a frame signal together with the first field signal as in the conventional case.

Since the above operation is repeated, this encoder circuit (12
) A color still image can be obtained by supplying the composite video signal obtained from the output of the monitor to a monitor.

[Problems to be Solved by the Invention] However, in the conventional device configured in this way, two systems of delay circuits and changeover switches are required, which not only complicates the circuit configuration but also increases the Due to variations in circuit gain between the signal that passes through the delay circuit and the through signal that does not pass through the delay circuit, the vertical scanning frequency fv
Flicker occurring at a frequency of 72 occurs in the reproduced video.

Adjustment to remove this flicker is extremely difficult, but as a means to do this,
126982 has been proposed, but there is a problem in that it requires a more complicated circuit configuration.

The present invention was made to solve these problems, and an object of the present invention is to provide an image reproducing apparatus that converts a field signal into a frame signal with a simple configuration and does not cause flicker.

[Means for Solving the Problem] The image reproducing device according to the present invention includes a delay circuit that delays multiple FM signals reproduced from a recording medium by 0°5H, and a delay circuit that delays multiple FM signals reproduced from a recording medium by 0°5H, and records the multiple FM signals delayed by this delay circuit. A switching circuit is provided that switches and outputs the non-delayed multiplexed FM signal reproduced from the medium at a field cycle, and the multiplexed FM signal output from this switching circuit is separated into a luminance signal and a color signal component, each of which is FM demodulated. R-Y signal and B-Y signal' which are synchronized luminance signal and demodulated line sequential signal.
The circuit is configured to input the signals into a signal synthesis circuit such as an encoder circuit.

[Function] In this invention, since the 0.5H delay for converting a field signal into a frame signal is performed at the stage of multiplexed FM signals, the delay circuit and the switching circuit can be integrated into one system, and the luminance after FM demodulation is 0.5H for signals and line sequential signals
A flicker-free color still image can be reproduced without creating a gain difference between delayed and non-delayed images.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, (1) to (6), (11), and (12) indicate the same or equivalent parts as the same reference numerals in FIG. (1) is a rotating magnetic sheet that is a recording medium, (2) is a reproducing head, (3) is a first filter circuit that extracts the FM modulation signal of the luminance signal from the reproduced multiplex FM signal, and (4) is A first FM demodulation circuit that FM demodulates the output signal of this circuit and outputs a luminance signal, (5) a second filter circuit that extracts a line-sequential FM modulation signal from the regenerated multiplexed FM signal, and (6) a , a second FM demodulation circuit which FM demodulates the output signal of this circuit (5) and outputs a color difference line sequential signal; (11) synchronizes the output color difference line sequential signal from this circuit (6) and outputs a color difference line sequential signal; A synchronization circuit (12), which is a color signal processing circuit that independently and simultaneously outputs the color difference signal of the first color difference signal and the second color difference signal, outputs the luminance signal output from the circuits (4) and (11) and the first color difference signal. An encoder circuit (13), which is a signal synthesis circuit that synthesizes the second color difference signals and outputs a composite video signal, is a delay circuit (14) that delays the reproduced multiplexed FM signal from the reproduction head (2) by 0.5H. ) is the reproduction multiplex F from the reproduction head (2)
The M signal is connected to one fixed terminal (14a) and the delay circuit (13
) is input to the other fixed terminal (14b), and one and the other of these input signals are alternately switched in a field period and output from the movable contact (14c).

Next, its operation will be explained. First, in the case of the first field, the movable contact (14c) of the changeover switch (14) is connected to one fixed contact (14a), and the multiplexed FM signal of the luminance signal and chromaticity signal reproduced by the reproduction head (2) is transmitted. It is supplied to the inputs of the first filter circuit (3) and the second filter circuit (5). The first filter circuit (3) extracts only the FM modulation signal component of the luminance signal from the multiplexed FM signal and supplies it to the first FM demodulation circuit (4). A luminance signal is obtained, and the second filter (5) extracts the line sequential signal F of the multiplexed FM signal.
A second FM demodulation circuit (6) extracts only the M modulation signal.
A line-sequential signal is obtained at the output of the second FM demodulation circuit (6), and this line-sequential signal is synchronized by the synchronization circuit (11), and the R-Y signal and B-Y signal are sent to the encoder circuit ( 1
2). In the encoder circuit (12), the signal is combined with the luminance signal to form a contrasting video signal and output.

If this is supplied to a monitor, a color image of the first field can be obtained.

Next, in the case of the second field, the movable contact (14c) of the changeover switch (14) is connected to the other fixed contact (14b). At this time, the multiplexed F reproduced by the reproduction head (2)
The M signal is delayed by 0.5H in the circuit (13) and then supplied to the first and second filter circuits (3) and (5).

By the way, since multiple FM signals require a wide frequency band ranging from low frequencies to high frequencies, the delay circuit (13) is also capable of delaying a wide band signal, such as an OCA delay line. The multiplexed FM signal delayed by 0.5H is separated by the first and second filter circuits (3) and (5) into a luminance signal F'M modulation signal and a color difference signal FM modulation signal, respectively. and the second FM demodulation circuits (4) and (6). The luminance signal output from the first FM demodulation circuit (4) has already been demodulated as an FM modulation signal with a delay of 0.5H, so
．． There is a delay of 5H, and the first field and the second field are in an interlaced scanning relationship. At this time, since the line sequential signal delayed by 0.5H is also output from the second FM demodulation circuit (6), the R-Y(No. 1!, B -Y signals are both delayed by 0.5H. When these are combined in the encoder circuit (12), a second field signal forming a frame together with the first field signal as in the conventional case is obtained.

By the way, when performing 0.5H delay after performing FM demodulation, that is, after converting the signal into a baseband video signal as in the conventional device, there is a circuit between the signal that has passed through the delay circuit and the signal that does not pass through the delay circuit. Even if there is some amplitude or DC component offset due to gain variations, flicker occurs in the reproduced image. However, in the state of de M signal, 0
, 5H delay, even if some amplitude difference occurs between the signal passed through the delay circuit and the signal not passed through the delay circuit, the baseband signal after FM demodulation has the characteristic that no amplitude difference or DC offset occurs.

Therefore, according to the present invention, when converting a field signal into a frame signal, flicker does not occur and
Moreover, good color still images can be obtained with a simpler configuration.

[Effects of the Invention] As described above, according to the present invention, the signal delay of 0.5H for converting a field signal into a frame signal can be reduced to 1
Since this is carried out in the form of FM modulated signals of frequency-division multiplexed luminance and chromaticity signals, it is possible to obtain an image reproducing apparatus with a simplified configuration and no flicker.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional image reproducing apparatus. In the figure, (1) is a rotating magnetic sheet (recording medium). (2) is the playback head, (3) is the first filter circuit, (
4) is the first FM demodulation circuit, (5) is the second filter circuit, (6) is the second FM demodulation circuit, (11) is the synchronization circuit (one color signal processing circuit), and (12) is the Encoder circuit (
(13) is a delay circuit, and (14) is a changeover switch (signal switching circuit). The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] A frame video signal is obtained by reproducing a field composite video signal from a recording medium in which the luminance signal of the field period and the line sequential signals of the first and second color difference signals are respectively FM modulated and frequency division multiplexed. In the image reproducing apparatus, a delay circuit delays a frequency division multiplexed FM signal reproduced from the recording medium by 1/2 horizontal period, and an FM signal reproduced from the recording medium and an FM signal delayed by the delay circuit are provided. a signal switching circuit that inputs each input signal and alternately selects and outputs one and the other of these input signals in a field period; a first filter circuit that extracts and outputs only the FM modulation signal of the luminance signal from the output signal of this circuit; A first FM demodulation circuit that FM demodulates the output signal of the first filter circuit and outputs a luminance signal, and a second FM demodulation circuit that extracts and outputs only the FM modulation signal of the color difference line sequential signal from the output signal of the signal switching circuit. a filter circuit, a second FM demodulation circuit that FM demodulates the output signal of the second filter circuit and outputs a color difference line sequential signal; a second FM demodulation circuit that synchronizes the output color difference line sequential signal of the second FM demodulation circuit; a color signal processing circuit that independently and simultaneously outputs a color difference signal and a second color difference signal; a luminance signal output from the first FM demodulation circuit; and first and second color difference signal outputs from the color signal processing circuit. What is claimed is: 1. An image reproducing device comprising: a signal synthesizing circuit which inputs these signals and outputs a synthesized composite video signal of these signals.