JPH09224209A - Video signal reproduction method and reproduction circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video signal reproduction method and a reproduction circuit of two-track parallel recording and reproducing system in which image quality of a search synthesis image is improved. SOLUTION: Information of a part RS for a time tx corresponding to a head interval in block information SQ reproduced by a Q head at a high speed is added to the head of block information MP reproduced at a high speed by a P head. Furthermore, information of part TM for a last time tx in the block information MP reproduced at a high speed by the P head is added to the end of the block information SQ reproduced by the Q head at a high speed. The signals are synthesized in time series and the result is outputted as a search synthesis signal. Thus, the information of the parts RS, TM having been aborted is effectively utilized and the increase in the information amount is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal reproducing method and a reproducing circuit, and more particularly to a video signal reproducing method and a reproducing circuit for parallel recording and reproducing a video signal of one field on two tracks on a recording medium.

[0002]

2. Description of the Related Art Conventionally, as a method of recording a wideband image signal such as a high-definition signal on a magnetic tape by a rotary head, the image signal is divided into an even line image signal and an odd line image signal, and these are divided into two lines. There is known a method of separately recording and reproducing simultaneously on the parallel tracks of JP-A-59-104703 and the like.

That is, in the above conventional video signal reproducing method and reproducing circuit, as shown in FIG.
First video heads P1 and P2 for even-line video signal recording / reproduction, which are arranged to face each other by 180 °,
A second video signal recording / reproducing device for odd-numbered lines, which is arranged at a position slightly behind the video heads P2 and P1 in the rotational direction, and is arranged to face each other by 180 °.
Image heads Q1 and Q2 are used.

The image heads P1 and Q1 have the same azimuth angle, the image heads P2 and Q2 have the same azimuth angle, and the image head image heads P1 and Q1 have different azimuth angles. In addition, the image heads P1 and P2 are at the same height and the rotating drum 4
0, the image heads Q1 and Q2 are attached to the rotary drum 40 at the same height as each other and at a height different from that of the image heads P1 and P2.

The image heads P1, P2, Q1 and Q2
As shown in FIG. 13, the tape pattern recorded on the magnetic tape by the helical scan method is such that a track inclined with respect to the longitudinal direction of the magnetic tape 41 is recorded every half rotation period of the rotary drum 40. Two tracks M1 and S2 are simultaneously and separately formed by Q2, and subsequently two tracks M2 and S1 are simultaneously and separately formed by the video heads P2 and Q1. Is repeated.

Incidentally, between the tracks M1 and S1 and between the tracks M2 and S2, illustration is omitted in FIG.
The audio tracks A1 and A2 are formed by a voice head having an azimuth angle different from those of P1, P2, Q1 and Q2, or a guard band is provided.

When the recorded video signal of the magnetic tape recorded in this way is reproduced at high speed, 180 ° is applied to the rotary drum 40 as in the conventional helical scan VTR.
A magnetic tape wound diagonally over a strong angle range is run at a speed higher than that at the time of recording.
Play by 1, P2, Q1 and Q2.

For this reason, the scanning loci of the video heads P1, P2, Q1 and Q2 cross the tracks because they have different inclinations from the track marks on the magnetic tape and traverse the tracks. As shown in FIG. 14, the recording portions (hereinafter, also referred to as blocks) indicated by MP, SP, and MP from the tracks M1, S1, and M1 having the same azimuth angle are sequentially reproduced by the video head P1 to reproduce the original self-recording. Not only the corresponding recording portion M1 but also the recording portion SP is reproduced from the track S1 recorded by another video head Q1 having the same azimuth angle, and this is included as false information. Further, not only the recorded portion SQ of the track S2 corresponding to the original self-recording / reproduction by the video head Q2 but also the recorded portion MQ from the track M2 recorded by another video head P2 having the same azimuth angle is reproduced.

Similarly, at the time of reverse search in which the magnetic tape running direction is opposite to the direction of recording, as shown in FIG. 15, not only the recording portion MP of the track M1 corresponding to the original self-recording / reproduction by the video head P1, but The recorded portion SP is also reproduced from the track S1 recorded by another video head Q1. Further, not only the recording portion SQ of the track S2 corresponding to the original self-recording / reproduction by the video head Q2, but also the track M recorded by another video head P2 having the same azimuth angle.
The recorded portion MQ is also reproduced from 2.

The reproduction signal of the portion recorded by the above-mentioned another video head is a false signal and deteriorates the reproduction signal quality. Therefore, conventionally, the video head P1 (or P2) reproduces only the video signals of even lines, and the video head Q2
In (or Q1), only the video signals of the odd lines are reproduced.

FIG. 16 shows a block diagram of a first example of a conventional video signal reproducing circuit which realizes the above high speed reproduction. In the figure, the video head P1 input through the switch 51.
The high-speed reproduction signal (or P2) is a frequency modulation (FM) signal and is supplied to the envelope detector 53,
It is supplied to the demodulator 56. At the same time, the high-speed reproduction signal of the video head Q2 (or Q1) input via the switch 52 is supplied to the envelope detector 54 and the demodulator 57.

The envelope detectors 53 and 54 detect the envelope of the input high-speed reproduction signal, and show the high level of the signal input period reproduced from the track portion having the same azimuth angle as the reproduction head, as shown in FIGS. Detection signal P shown
Outputs ENV and QENV. The AND circuit 55 takes the logical product of these detection signals PENV and QENV and outputs the pulse shown in FIG. 17 (C).

On the other hand, the first high-speed playback video signal demodulated by the demodulator 56 and the second high-speed reproduced video signal demodulated by the demodulator 57.
The high-speed reproduced video signals of are respectively supplied to the switch circuit 58 and passed through the switch circuit 58 only during the high level period of the output pulse from the AND circuit 55.

As a result, as shown in FIG. 18 (A), the video head P input via the switch 51.
1 (or P2) alternate reproduction high-speed reproduction signal from the track recording portions MP and SP, and alternate reproduction high speed from the track recording portions SQ and MQ input by the video head Q1 (or Q2) via the switch 52. As for the reproduction signal, only the reproduction video signal from the recording portion corresponding to the self-recording and reproduction of MP and SQ, in which both are reproduced at the same time, is selected as shown in FIG. 18B and input to the search memories 59 and 60, respectively. Will be stored and stored.

The high-speed reproduction video signals alternately read from the search memories 59 and 60 are time-divisionally combined by the switch 61 and output to the output terminal 62 as a high-speed reproduction video signal (search composite signal).

Although FIG. 17 shows the envelope detection signal during the forward search and the output signal waveform of the AND circuit 55, the detection signal PENV during the reverse search,
The output signal waveforms of QENV and the AND circuit 55 are shown in FIG.
As shown in (A), (B) and (C).

In this way, during the forward search, as shown by A to C in FIG. 25A, some information in one field is in the same direction as the time axis on the tape, for example, every other field. It is played back and at the time of reverse search,
As shown by A to C in FIG. 25B, a part of information in one field is reproduced every other field in the direction opposite to the time axis on the tape.

FIG. 20 shows a block diagram of a second example of a conventional video signal reproducing circuit. 16, those parts which are the same as those corresponding parts in FIG. 16 are designated by the same reference numerals, and a description thereof will be omitted. The example of FIG. 16 is a conventional high-speed reproducing circuit in the case where there is no space between the video heads P1 and Q2 (P2 and Q1), but this conventional circuit is an example in which there is a space between both video heads. The above-mentioned video heads P1 and Q2 used for 2-track parallel recording and reproduction
The pair of (P2 and Q1) is often arranged with a certain interval because the head drum structure is difficult or the effect of crosstalk between the two heads is desired to be small. .

Even in this case, the AND circuit 55 of FIG. 20 calculates the logical product of the envelope detection signals PENV and QENV, and the output of the AND circuit 55 controls the switching of the switch circuit 58 so that only the information corresponding to the original recording / reproduction necessary. Can be extracted.

That is, as schematically shown in FIG. 21A, the video head P1 input via the switch 51.
Alternate reproduction high-speed reproduction signals (P head reproduction information) from the recording portions MP and SP of the track by (or P2) and the video head Q1 (or Q) input via the switch 52.
2) Alternate reproduction high-speed reproduction signal (Q head reproduction information) from the recorded portions SQ and MQ of the track is only the reproduced video signal from the recorded portion corresponding to self-recording of MP and SQ, in which both are reproduced simultaneously. Is output from the switch circuit 58.

However, since there is a head interval, even if the information is reproduced at the same time point in time, the video head P1
The positional relationship in one screen between the video signal of one block reproduced by (or P2) and the video signal of one block reproduced by the video head Q2 (or Q1) is deviated by the head interval.

Therefore, in the example shown in FIG. 20, the P head reproduction information input to the search memory 64 through the switch circuit 58 has a head interval larger than that of the Q head reproduction information input to the search memory 65 through the switch circuit 58. Writing is performed as schematically shown in FIG. 21B with a delay of a corresponding time t _x . RSTWM and RSTWS indicate write start pulses for the search memories 64 and 65.

FIG. 22 shows a block diagram of a third example of a conventional video signal reproducing circuit. 16, those parts which are the same as those corresponding parts in FIG. 16 are designated by the same reference numerals, and a description thereof will be omitted. This conventional circuit is an example in which there is a space between both video heads.

In FIG. 22, the envelope detector 5
The output detection signals PENV and QENV of 3, 54 are shown in FIG.
23A and 23B, the output signal of the AND circuit 55 is as shown in FIG. 23C, which is similar to the conventional circuit shown in FIG. Circuit 5
The output signal of No. 5 is directly supplied to the switch circuit 68 as a switching signal, while it is delayed by the delay circuit 66 by the time t _x corresponding to the head interval, and is then changed to the signal shown in FIG. Is supplied as a switching signal.

On the other hand, regarding the P head reproduction information of the demodulator 56 and the Q head reproduction information of the demodulator 57, as shown schematically in FIG. , Because there is a head gap, the video head Q2
(Or Q1) P head reproduction information of the demodulator 56 reproduced by the preceding video head P1 (or P2) is delayed by time t _{x in the} delay circuit 65 shown in FIG. 22, and then supplied to the switch circuit 67, Here, switching is performed by the switching signal from the delay circuit 66. On the other hand, the Q head reproduction information from the demodulator 57 is not delayed and the switch circuit 6
It is supplied to 0 and is switched by the output signal of the AND circuit 55.

Thus, as schematically shown in FIG. 24B, the P head reproduction information inputted to the search memory 59 through the switch circuit 67 is reproduced as the Q head reproduction information inputted to the search memory 60 through the switch circuit 68. The time lag due to the head interval is corrected compared to the information.

[0027]

However, when there is a space between the above-mentioned video heads P1 and Q2 (P2 and Q1), the search combined signal output to the output terminal 62 of FIG. 20 or 22 is displayed on the display device. When the image is displayed on the screen, the image of the above-mentioned gap of the head interval has the image information of the rewritten new field and the image information of the old field before being rewritten every other line, so that the image quality deteriorates. To do. Moreover, the higher the speed of the search (the higher the speed ratio of the high speed reproduction), the less the correlation of the images in the shifted portion, and the image quality further deteriorates.

Therefore, it is considered that the image information of the misaligned portion is discarded, but originally, the self-recording / reproduction information is small in the two-track parallel recording, and the image of even lines and the image of odd lines are rewritten at the same time as the speed search becomes faster. Since the part (image signal in the same field on the recording tape) is reduced and each block image embedded in the search composite image fluctuates considerably on the time axis, the image quality is also significantly deteriorated and a certain speed ratio With the above, effective image information cannot be obtained at all.

The present invention has been made in view of the above points,
An object of the present invention is to provide a video signal reproducing method and a reproducing circuit of a two-track parallel recording / reproducing system capable of improving the image quality of a search composite image.

Another object of the present invention is to provide a video signal reproducing method and a reproducing circuit of a two-track parallel recording / reproducing system capable of obtaining a high-speed reproduced image at a higher speed than ever before.

Still another object of the present invention is to provide a video signal reproducing method and a reproducing circuit of a two-track parallel recording / reproducing system in which the motion of a moving image is smooth.

[0032]

In order to achieve the above object, a video signal reproducing method according to the present invention according to claim 1 is a pair of first and second azimuth angles which are provided so as to face each other with respect to a rotating surface of a rotating body. One of the even line and the odd line of the video signal of one field is formed by the first head and the pair of second heads provided on the rotating surface so as to be adjacent to and opposite the first head and have different azimuth angles. The video signal of the first line is formed by the first head, and the video signal of the other line is formed by the second head by the first head.
By forming a second track having a different azimuth angle in parallel with the first track at the same time as the first track, an already recorded video signal of a tape-shaped recording medium in which a video signal is recorded in units of two parallel tracks, In the video signal reproducing method of reproducing the tape-shaped recording medium at a higher speed than that at the time of recording, the first head is provided ahead of the second head by a constant distance in the rotation direction, and the first head is provided. The reproduction signal from the second head is relatively delayed with respect to the reproduction signal from the second head by a time corresponding to a constant interval to adjust the time.
Of the video signal block reproduced from the second track by the first head is added to the beginning of the video signal reproduced by the first head for a time period corresponding to a constant interval, and interpolation is performed. The video signal block reproduced from the first track is added to the end of the reproduction video signal of the second head by a signal portion corresponding to a certain time interval from the end of the video signal block, and interpolation is performed. The reproduced video signal and the second reproduced video signal are combined in time series to obtain a high-speed reproduced video signal.

In order to achieve the above object, the video signal reproducing circuit of the present invention detects the envelope of the reproduced signal from the first head which is provided ahead of the second head by a certain distance in the rotational direction. A first detector, a second detector for detecting an envelope of a reproduction signal from the second head, a first reproduction signal from the first head and a reproduction signal from the second head, respectively. First demodulated and timed with a relative delay by a time corresponding to a fixed interval
Demodulation means for outputting the reproduced video signal and the second reproduced video signal in parallel, a signal generation circuit for generating a switching signal based on the output detection signals of the first and second detectors, and the first or second And a second memory for storing the reproduced video signal of 1) and reading it as a reproduced video signal of one line, and a second memory for storing the second or first reproduced video signal and reading it as a reproduced video signal of the other line. A first memory for selecting a signal portion for a time corresponding to a constant interval from the beginning of the second reproduced video signal block output from the demodulation means and subsequently a first reproduced video signal based on a switching signal. To the second playback video signal and then the first playback video signal.
Switching means for selecting, based on the switching signal, a signal portion corresponding to a certain time interval from the end of the reproduced video signal block of 1) based on the switching signal and inputting it to the second memory;
And a synthesizing unit for synthesizing the reproduced video signals read from the second memory in time series to obtain a high-speed reproduced video signal.

In the above-described video signal reproducing method and reproducing circuit of the present invention, the other head is utilized by utilizing the image of the misalignment portion, which is caused by the existence of the mounting interval between the first and second heads. The amount of information can be increased by interpolating in the high-speed reproduced video signal of.

In order to achieve the above-mentioned object, the video signal reproducing method of the present invention as defined in claim 3 is performed from the first track reproduced at high speed by the first head and the second track of the adjacent field. Of the reproduced signal from the second track and the reproduced signal from the first track of the adjacent field reproduced at high speed by the second head.
The reproduction signal from the first track reproduced at a high speed by the second head is replaced and added to the reproduction signal of the first track reproduced at a high speed by the head of The reproduced signal from the second track is interpolated and multiplexed to generate a first multiplexed signal,
The reproduction signal from the second track reproduced at a high speed by the first head is replaced and added to the reproduction signal of the second track reproduced at a high speed by the first head and the second signal reproduced at the high speed by the second head. The reproduced signal from the first track is interpolated and multiplexed to generate the second multiplexed signal, and the first and second multiplexed signals are time-sequentially combined to obtain a high-speed reproduced video signal. It is a thing.

Further, the video signal reproducing circuit of the present invention according to claim 5 detects the envelope of the reproduced signal from the first head, which is provided ahead of the second head by a constant distance in the rotational direction. 1 detector, a second detector for detecting the envelope of the reproduction signal from the second head, and a first detector
The first reproduction signal from the head and the reproduction signal from the second head, respectively, and the first reproduction video signal which is time-delayed by relatively delaying by a time corresponding to a constant interval. The demodulation means for outputting the second reproduction video signal in parallel, the signal generation circuit for generating the switching signal based on the output detection signals of the first and second detectors, and the first or second reproduction video signal Output from demodulation means: first memory for storing and reading as reproduced video signal of one line; second memory for storing second or first reproduced video signal and reading as reproduced video signal of other line; First done
Video signal of the self-recording / reproducing portion of the first track which is reproduced at high speed by the head, the reproduced video signal from the first track which is reproduced at high speed by the second head, and high speed reproduction by the first head The reproduced video signal from the reproduced second track is selected based on the switching signal and input to the first memory, and the reproduced signal of the self-recording / reproducing portion of the second track which is reproduced at high speed by the second head. A reproduction signal from the second track which is reproduced at high speed by the first head and a reproduction signal from the first track which is reproduced at high speed by the second head, based on the switching signal. A configuration having switching means for inputting to the memory, and synthesizing means for synthesizing the reproduced video signals read from the first and second memories in time series to obtain a high-speed reproduced video signal, Those were.

In the invention described in claims 3 and 5, the first
And, in each playback video signal of the second head, the playback video signal block of a portion other than the self-recording / playback which was conventionally discarded is interpolated,
By replacing the reproduced video signal block of the same even-numbered line or the odd-numbered line as the self of the other head in the reproduced video signal of its own head, both reproduced video signal blocks can be used, which results in 3 Double the amount of information can be obtained.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of a video signal reproducing circuit according to the present invention. In this embodiment and other embodiments described later, the video heads P1 and P2 having the configuration shown in FIG. 12 are the video heads Q2 and Q.
The recorded video signal of the magnetic tape of the tape pattern shown in FIG. 13 which is arranged in advance in the rotation direction with a space X larger than 1 and which is parallel-recorded in two tracks shown in FIG. 13 is reproduced.

In FIG. 1, the high-speed reproduction signal of the video head P1 (or P2) input through the switch 11 is
It is a frequency-modulated (FM) signal and is supplied to the demodulator 13 while being supplied to the envelope detector 15. Also,
At the same time, the high speed reproduction signal of the video head Q2 (or Q1) input via the switch 12 is also frequency-modulated (F
M) signal, which is supplied to the demodulator 14 while being supplied to the envelope detector 16.

Here, the self-recording / reproducing portion which can be reproduced by one scan of the head in one field of the search / combine screen is scattered as shown by A to C in FIG. 2 (A).
The video head P1 (or P2) is the video head Q2.
(Or Q1) is scanned on the magnetic tape in advance of the interval X with respect to (or Q1), so that the video head P1 (or P2) is track M1 (or M2) as schematically shown in FIG. The position of scanning the
1) is ahead of the position where the track S2 (S1) is being scanned by the distance X.

However, the above-mentioned video head P1 (or P
2) and the video head Q2 (or Q1) are reproducing at the same time with the head interval X, the reproduction signals of both video heads (P head reproduction information and Q head reproduction information)
Are simultaneously obtained from time t1 to t2 as shown in FIG. However, the P head reproduction information leads the Q head reproduction information by a time t _x corresponding to the head interval X over the information originally reproduced.

Information M of one block reproduced from the track M1 (or M2) by the video head P1 (or P2).
P and the video head Q2 (or Q1) is on track S2 (S
When the information of 1 block reproduced from 1) is viewed as a part of the search combined image, the area 33 of the information MP of 1 block is lower than the area 34 of the information SQ of 1 block as shown in FIG. 2B. Located on the side.

By the way, in the two-track parallel recording in which the video signal of one field is divided into even lines and odd lines and recorded, in the video signal recording part of the odd lines having the same positional relationship as the video signal recording part of the even lines. Has line correlation. That is, the odd line information of the RS portion shown in FIG. 3A has a line correlation with the even line information recorded in the RM portion adjacent thereto, and the even line information of the TM portion includes the TS portion adjacent thereto. There is line correlation with the odd line information recorded in.

Therefore, in the information of the RS portion above the area 34 of the information SQ of one block shown in FIGS. 2B and 3A, the information of the upper portion of the area 33 of the information MP of one block is shown in FIG. The RM portion shown in (A) is interpolated, and the TS portion shown in FIG. 3A below the area 34 of the information SQ of one block is converted to the TS portion shown in FIG. Interpolate.

That is, when the head scanning portion on the tape pattern shown in FIG. 3A is reproduced, reproduction information obtained at the timing schematically shown in FIG. Is corrected and then interpolated. Regarding the interpolated portion, although the vertical resolution is lowered, it is possible to reproduce twice the shift X in the vertical alignment, and the image quality of the search combined image is improved by increasing the amount of this information.

Referring back to FIG. 1 again, the envelope detectors 15 and 16 detect the envelope of the input high-speed reproduction signal and detect the high level of the signal input period reproduced from the track portion having the same azimuth angle as the reproduction head. Signal P
ENV and QENV are generated and output to the control (CTL) circuit 17. The control circuit 17 first calculates the logical product of these detected signals to obtain the signal S shown in FIG.
1 is generated.

The control circuit 17 subsequently delays this signal S1 by a time t _x corresponding to the head interval X, and the delay time shown in FIG.
The signal S2 shown in (C) is generated, and these signals S2 and
By taking the logical product of 1 and S2, the signal S3 shown in FIG. 4D is obtained, and from the signals S1 and S2 to FIG.
Signals S4 and S5 shown in (F) are generated.

On the other hand, the first high-speed reproduction video signal demodulated by the demodulator 13 in FIG. 1 (P head reproduction information MP in FIG. 3B) is supplied to the delay circuit 18, where the head interval X After being delayed for a time t _x corresponding to the shift, the signal S2
Of the signal S5 is supplied to the search memory 23 through the switch circuit 19 which is turned on only during the high level period, and is supplied to the search memory 24 through the switch circuit 20 which is turned on only during the high level period of the signal S5.

Further, the second high-speed reproduction video signal demodulated by the demodulator 14 (Q head reproduction information S of FIG. 3 (B)).
Q) is supplied to the search memory 24 through the switch circuit 21 that is turned on only during the high level period of the signal S1 without being delayed, while it is supplied to the search memory 24 through the switch circuit 22 that is turned on only during the high level period of the signal S4. 23. The search memories 23 and 24 perform the write operation by the same write pulse RSTW.

As a result, after the information of the RS portion of the first time t _x in the Q head information SQ input via the switch circuit 22 is written in the search memory 23, it is input via the switch circuit 19. P head reproduction information MP
Is written. Further, Q head information S input to the other search memory 24 via the switch circuit 21.
After Q is written, the information of the TM portion at the last time t _x in the P head reproduction information MP input via the switch circuit 20 is written.

Therefore, from the search memory 23, as shown in FIG.
As schematically shown in (A), the information of the RS portion and the P head reproduction information MP are time-sequentially combined and read,
Further, from the search memory 24, the Q head reproduction information SQ and the information of the TM portion are combined in time series and read. These signals are alternately selected by the switch 25, time-division multiplexed, and output to the output terminal 26 as a search combined signal.

As described above, in this embodiment, even if there is a head mounting position interval, the image information is increased as compared with the prior art, so that it is possible to obtain a high-quality high-speed reproduced image.

FIG. 5 shows a block diagram of the second embodiment of the present invention. In the figure, the P head reproduction information and Q
The head reproduction information is supplied to the time-axis conversion circuit 35, where it is time-axis converted and returned to a single-system signal, and a switch and interpolation circuit 37 that performs the same switching and interpolation operations as shown in FIG. Is supplied to the search memory 36, and the search synthesis signal interpolated in the same manner as above is output under the control of the control circuit 38. This embodiment is characterized in that the P head reproduction information and the Q head reproduction information are returned to one system of signals and then processed.

FIG. 6 is a block diagram of a video signal reproducing circuit according to a third embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
The outline of this embodiment will be described first.

Information obtained during high-speed reproduction has the following three patterns.

A period in which an even line video signal and an odd line video signal in the same field are both obtained.

A period in which the video head P1 (or P2) picks up the video signal information of the odd line of the adjacent track (field).

A period in which the video head Q2 (or Q1) picks up the video signal information on the even line of the adjacent track (field).

As for the conventional method, the effective information can be obtained by taking the logical product of the envelope detection signals of the reproduced signals from the video head P1 (or P2) and the video head Q2 (or Q1).

The information of the period of time is the information that the video head P1 picks up the track S1 recorded by the video head Q1 and the track S2 recorded by the video head Q2.
2 is the information to pick up. This is SP block information.
In order to input the SP block information picked up by the video head P1 (or P2) to the search memory which outputs the video signal of the odd line, the signal paths of that period are switched to effectively use the information that was conventionally discarded. it can.

However, when the search combined image is set,
The image information of this part consists of the image information of the new field that has been rewritten and the image information of the old field that has not been rewritten.
Exists every other line. This causes deterioration of image quality.

By the way, in the two-track parallel recording in which the video signal of one field is divided into even-numbered lines and odd-numbered lines and recorded, even if there is a head interval, it is adjacent to the recorded tracks of even-numbered lines as described above. The information of the adjacent recording portions of the recorded tracks of the odd-numbered lines is electrically corrected and recorded so as to have line correlation with each other.

Therefore, it is extremely effective to interpolate the video signal portion of the even line having the same positional relationship with the SP block information which is originally the odd line track information. As the control signal, a signal when the envelope detection signal of the reproduction signal of the video head Q2 (or Q1) is invalid and the envelope detection signal of the reproduction signal of the video head P1 (or P2) is valid is used. To use.

Information of the period is for the video head P1.
The information is information that the video head Q1 picks up the track M1 recorded by the video head Q1 and the information that the video head Q2 picks up the track M2 recorded by the video head P2. This is MQ block information. By effectively switching the signal path during that period so that the MQ block information picked up by the video head Q2 (or Q1) is input to the search memory that outputs the video signal of even lines, the information that was conventionally discarded can be effectively used. it can.

However, when the search combined image is set,
The image information of this part consists of the image information of the new field that has been rewritten and the image information of the old field that has not been rewritten.
Exists every other line. This causes deterioration of image quality.

However, as described above, the information in the adjacent recording portions of the odd-numbered track recorded adjacent to the even-numbered track is electrically corrected and recorded so as to have line correlation with each other. Therefore, it is extremely effective to interpolate the video signal portion of the odd line having the same positional relationship with the MQ block information which is originally the even line track information. As the control signal, a signal when the envelope detection signal of the reproduction signal of the video head Q2 (or Q1) is valid and the envelope detection signal of the reproduction signal of the video head P1 (or P2) is invalid is used. To use.

The embodiment of FIG. 6 and FIG. 9 described later is constructed in view of the above points. In the embodiment shown in FIG. 6, the envelope detector 15 detects the envelope of the high-speed reproduction signal from the video head P1 (or P2) and reproduces from the track portion having the same azimuth angle as the reproduction head at a high level during the signal input period. 7A, the envelope detector 16 detects the envelope of the high-speed reproduction signal from the video head Q2 (or Q1) and reproduces it from the track portion having the same azimuth angle as the reproduction head. Of the high level during the signal input period
The detection signal QENV shown in (B) is generated. In this embodiment, there is no head interval.

The control (CTL) circuit 30 receives the detection signals PENV and QENV as input signals, calculates the logical product of these signals, and outputs the signal S1 shown in FIG. 7C.
To generate the detection signal PENV and the detection signal QENV.
The signal T1 shown in FIG. 7D is obtained by taking the logical product of the inversion signals of
Is generated, and a logical product of the inverted signal of the detection signal PENV and the detection signal QENV is taken to obtain the signal R1 shown in FIG.
Generate

On the other hand, the P head reproduction information output from the demodulator 13 and the Q head reproduction information output from the demodulator 14 are obtained from respective blocks of two adjacent tracks schematically shown in FIG. 8A. It is a video signal reproduced at high speed. However, in this video signal, SP block information is originally odd line track information (S track information), and M
The Q block information is originally even-line track information (M track information), and the track information actually reproduced is the one schematically shown in FIG. 8B.

Therefore, in this embodiment, the demodulator 13
The P head reproduction information outputted from the demodulator 14 and the Q head reproduction information outputted from the demodulator 14 are passed through the switch circuit 27 which is turned on during the high level period of the signal S1, and thereby the signal portion self-recorded and reproduced. Only the extracted data is supplied to the search memories 23 and 24 in parallel and written therein.

Further, the P head reproduction information output from the demodulator 13 is passed through the switch circuit 28 which is turned on during the high level period of the signal T1, so that only the SP block information portion is extracted and the search memory. 23 and 24 are respectively supplied in parallel and written.

Further, the Q head reproduction information output from the demodulator 14 is passed through the switch circuit 29 which is turned on during the high level period of the signal R1, so that only the MQ block information portion is extracted and the search memory is searched. 23 and 24 are respectively supplied in parallel and written.

As a result, from the search memory 23, as shown in FIG.
As schematically shown in (C), the video head P1 (or P
The M track reproduction information self-recorded / reproduced in 2), the SP block information interpolated into the even line information, and the MQ block information replaced from the Q head reproduction information are combined in time series and read. In addition, the search memory 24
As shown in FIG. 8 (C), the video head Q
2 (or Q1), the S track reproduction information self-recorded / reproduced, the MQ block information interpolated into the odd line information, and the SP block information replaced from the P head reproduction information are combined in time series and read. . These signals are alternately selected by the switch 25, time-division multiplexed, and output to the output terminal 26 as a search combined signal.

In this embodiment, the interpolated information portion has a lower vertical resolution than a normal reproduced image, but the information that was conventionally discarded can be effectively used, and the relative information that cannot be obtained by the information. By interpolating the information on the image side to be reproduced, the information amount three times as large as that in the conventional accelerated reproduction can be obtained. For this reason, in this embodiment, the image quality of the search combined image can be dramatically improved as compared with the conventional one, and the motion of the moving image becomes smooth in particular.

FIG. 9 shows a block diagram of a fourth embodiment of a video signal reproducing circuit according to the present invention. In the figure, the same components as those in FIGS. 1 and 6 are designated by the same reference numerals, and the description thereof will be omitted. This embodiment is an example in which the image heads P1 and P2 are arranged on the rotating drum in advance of the image heads Q2 and Q1 by X in the rotational direction.

In FIG. 9, the control circuit 31 controls the detection signals PENV and QENV shown in FIGS.
10 as an input signal, and taking the logical product of these,
The signal S1 shown in FIG. 10C is generated, and the signal S1 shown in FIG.
The signals T1 and R1 shown in FIG.
Signals S2 and T2 shown in FIGS. 10D and 10F are generated by delaying T1 by a time t _x corresponding to the head interval X.

The output P head reproduction information of the demodulator 13 is delayed by the delay circuit 18 relative to the output Q head reproduction information of the demodulator 14 by the time t _x, and the switch circuit 1
9 and 32 are supplied. The switch circuit 19 is turned on during the high level period of the signal S2, and the switch circuit 32 is turned on by the signal T.
It is turned on for a high level period of 2. As a result, the output P head reproduction information of the demodulator 13 is corrected for the deviation corresponding to the head interval X, and the same information as in the third embodiment is written in the search memories 23 and 24, respectively.

FIG. 11A shows P in this embodiment.
FIG. 11 shows head reproduction information and Q head reproduction information.
(B) shows the track information which is actually reproduced. Further, FIG. 11C schematically shows the reproduced signals output from the search memories 23 and 24.

By the same configuration as shown in FIG. 5,
It is also possible to perform the same signal processing as in FIG. 6 and FIG. 9 after converting the signals reproduced in two systems into the signals of one system by time-axis conversion.

The present invention is not limited to the above embodiment, and the delay circuit 18 may be provided on the input side of the demodulator 13. Further, in the above embodiments, the speed of high-speed reproduction is arbitrary, and the present invention can be applied to both forward search and reverse search.

[0081]

As described above, according to the first and second aspects of the present invention, the image of the misaligned portion which is generated due to the existence of the mounting interval between the first and second heads is displayed. By using it to interpolate in the high-speed playback video signal of the other head to increase the amount of information, the image quality of the high-speed playback image can be improved compared to the conventional one, and the motion of the high-speed playback image can be made smooth. it can.

Further, according to the present invention as defined in claims 3 to 5, among the reproduced video signals of the first and second heads, the reproduced video signal blocks of the portions other than the self-recording / reproducing which were conventionally discarded are interpolated, By replacing the reproduced video signal block of the same even-numbered line or odd-numbered line as the self of the other head in the reproduced video signal of its own head and using both reproduced video signal blocks, the information amount three times as large as that in the conventional case can be obtained. Since it is obtained, the image quality of the high-speed playback image can be dramatically improved, especially the motion of the moving image can be smoothed, and further, the high-speed playback of the double speed ratio which is much faster than the conventional one can be performed. .

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of an image obtained by one head scan during high-speed reproduction and one rewriting block.

FIG. 3 is an explanatory diagram of a scanning portion on the tape pattern of the head according to FIG. 1 and reproduction information.

4 is a diagram showing reproduction information output by FIG. 1 and switching signal waveforms of respective parts in FIG.

FIG. 5 is a block diagram of a second embodiment of the present invention.

FIG. 6 is a block diagram of a third embodiment of the present invention.

FIG. 7 is a switching signal waveform diagram of each part of FIG.

FIG. 8 is a diagram schematically showing reproduction information and output information of each part of FIG.

FIG. 9 is a block diagram of a fourth embodiment of the present invention.

FIG. 10 is a switching signal waveform diagram of each part of FIG.

FIG. 11 is a diagram schematically showing reproduction information and output information of each part of FIG.

FIG. 12 is a diagram illustrating a mounting state of a head to which the present invention is applied to a rotary drum.

FIG. 13 is a diagram showing an example of a tape pattern to which the present invention is applied.

FIG. 14 is an explanatory diagram of head scanning and a reproducing portion at the time of forward search.

FIG. 15 is an explanatory diagram of head scanning and a reproducing portion at the time of reverse search.

FIG. 16 is a configuration diagram of a first example of a conventional video signal reproducing circuit.

FIG. 17 is a switching signal waveform diagram of each part of FIG. 16.

FIG. 18 is a diagram schematically showing reproduction information and output information of each part of FIG.

FIG. 19 is an envelope detection signal waveform diagram at the time of reverse search.

FIG. 20 is a configuration diagram of a second example of a conventional video signal reproducing circuit.

21 is a diagram schematically showing reproduction information and output information of each part of FIG.

FIG. 22 is a configuration diagram of a third example of a conventional video signal reproducing circuit.

FIG. 23 is a switching signal waveform diagram of each part of FIG. 22.

FIG. 24 is a diagram schematically showing reproduction information and output information of each part of FIG. 22.

FIG. 25 is a diagram schematically showing information obtained by one scan of the head during high speed reproduction.

[Explanation of symbols]

11, 12 Head changeover switch 13, 14 Demodulator (demodulation means) 15 Envelope detector (first detector) 16 Envelope detector (second detector) 17, 30, 31, 38 Control circuit (signal generation circuit) ) 18 delay circuit (demodulation means) 19, 20, 21, 22, 27, 28, 29, 32 switch circuit (switching means) 23 search memory (first memory) 24 search memory (second memory) 25 switch ( Synthesizing means) 26 Search synthesized signal output terminal 33 Block information MP area 34 Block information SQ area 35 Time axis conversion circuit 36 Search memory 37 Switch and interpolation circuit P1, P2 Video head (first head) Q1, Q2 Video head (Second head) PENV, QENV Envelope detection signals S1 to S5, T1, 2, R1, R2 switching signals MP, SQ high-speed playback portion (playback information) for self-recording / playback SP block information (recording portion) where the video heads P1 and P2 pick up tracks recorded by the video heads Q1 and Q2 MQ video head P1 Block information (recording portion) where the video heads Q1 and Q2 pick up the tracks recorded by P2, P2

Claims (5)

[Claims] 1. A pair of first heads having different azimuth angles, which are provided so as to face the rotation surface of the rotating body, and mutually provided so as to be adjacent to and opposite the first head on the rotation surface. By the pair of second heads having different azimuth angles, the video signal of one line of even line and odd line of the video signal of one field forms the first track by the first head, and the other The video signal of the line is imaged in units of two parallel tracks by forming a second track having a different azimuth angle from the first track in parallel with the first track by the second head. A video signal reproducing method for reproducing an already-recorded video signal of a tape-shaped recording medium on which a signal is recorded at a speed of the tape-shaped recording medium higher than that at the time of recording, wherein the first head is The second head is provided ahead of the second head by a constant interval, and the reproduction signal from the first head is relative to the reproduction signal from the second head by a time corresponding to the constant interval. The video signal block reproduced from the second track by the second head is delayed for time adjustment, and a signal portion for a time corresponding to the fixed interval from the beginning of the video signal block is reproduced by the first head. The signal is added to the beginning of the signal and interpolated, and the signal portion before the time corresponding to the fixed interval from the end of the video signal block reproduced from the first track by the first head is recorded by the second head. A high-speed playback video signal is obtained by adding the playback video signal to the end of the playback video signal and interpolating, and synthesizing the playback video signal of the first head and the second playback video signal after interpolation in time series. When Video signal playback method. 2. A pair of first heads having different azimuth angles, which are provided so as to face the rotation surface of the rotating body, and a pair of first heads, which are provided so as to be adjacent to and opposite the first head, on the rotation surface. By the pair of second heads having different azimuth angles, the video signal of one line of even line and odd line of the video signal of one field forms the first track by the first head, and the other The video signal of the line is imaged in units of two parallel tracks by forming a second track having a different azimuth angle from the first track in parallel with the first track by the second head. In a video signal reproducing circuit for reproducing an already recorded video signal of a tape-shaped recording medium on which a signal is recorded, at a speed of the tape-shaped recording medium higher than that at the time of recording, Also, a first detector for detecting the envelope of the reproduction signal from the first head, which is provided in advance in the rotation direction by a constant interval, and a second detector for detecting the envelope of the reproduction signal from the second head. The detector, the first reproduction signal from the first head and the reproduction signal from the second head are respectively demodulated, and the time is adjusted by relatively delaying the time corresponding to the constant interval. Demodulating means for outputting in parallel the first reproduced video signal and the second reproduced video signal, and a signal generation circuit for generating a switching signal based on the output detection signals of the first and second detectors, A first memory that stores the first or second reproduced video signal and reads it as a reproduced video signal of the one line; and a second memory that stores the second or first reproduced video signal and reproduces the other line As a video signal A second memory for reading, a signal portion for a time corresponding to the constant interval from the beginning of the second reproduction video signal block output from the demodulation means, and subsequently the switching of the first reproduction video signal. A signal selected based on a signal and input to the first memory, followed by the second reproduced video signal and the first reproduced video signal.
Switching means for selecting, based on the switching signal, a signal portion before the end of the reproduced video signal block corresponding to the certain interval based on the switching signal, and inputting the selected signal portion to the second memory; and the first and second memories. And a synthesizing unit for synthesizing the reproduced video signals read from the respective units in time series to obtain a high-speed reproduced video signal. 3. A pair of first heads provided opposite to a rotation surface of a rotating body and having different azimuth angles, and a pair of first heads provided adjacent to the rotation surface and adjacent to the first head. By the pair of second heads having different azimuth angles, the video signal of one line of even line and odd line of the video signal of one field forms the first track by the first head, and the other The video signal of the line is imaged in units of two parallel tracks by forming a second track having a different azimuth angle from the first track in parallel with the first track by the second head. A video signal reproducing method for reproducing an already-recorded video signal recorded on a tape-shaped recording medium at a speed of the tape-shaped recording medium higher than that at the time of recording, wherein the first head is From the first track reproduced at high speed and the second track of the adjacent field, and from the second track reproduced at high speed by the second head and the first track of the adjacent field. Of the reproduction signal of the first track, the reproduction signal of the first track reproduced by the first head at a high speed is replaced with the reproduction signal of the first track reproduced by the second head at a high speed. In addition, the reproduced signal from the second track reproduced at high speed by the first head is interpolated and multiplexed to generate a first multiplexed signal, and the second reproduced at high speed by the second head. The reproduction signal of the second track reproduced at high speed by the first head is replaced and added to the reproduction signal of the track No. First played
Reproduction signals from the tracks are interpolated and multiplexed to generate a second multiplexed signal, and the first and second multiplexed signals are time-sequentially combined to obtain a high-speed reproduced video signal. Video signal playback method. 4. The first head is provided ahead of the second head by a constant distance in the rotational direction, and the reproduction signal from the first head is compared with the reproduction signal from the second head. 4. The video signal reproducing method according to claim 3, wherein the first and second multiplexed signals are generated after the time is adjusted by relatively delaying by a time corresponding to the constant interval. 5. A pair of first heads having different azimuth angles, which are provided so as to face the rotation surface of the rotating body, and a pair of first heads, which are provided so as to be adjacent to and opposite the first head, on the rotation surface. By the pair of second heads having different azimuth angles, the video signal of one line of even line and odd line of the video signal of one field forms the first track by the first head, and the other The video signal of the line is imaged in units of two parallel tracks by forming a second track having a different azimuth angle from the first track in parallel with the first track by the second head. In a video signal reproducing circuit for reproducing an already recorded video signal of a tape-shaped recording medium on which a signal is recorded, at a speed of the tape-shaped recording medium higher than that at the time of recording, Also, a first detector for detecting the envelope of the reproduction signal from the first head, which is provided in advance in the rotation direction by a constant interval, and a second detector for detecting the envelope of the reproduction signal from the second head. The detector, the first reproduction signal from the first head and the reproduction signal from the second head are respectively demodulated, and the time is adjusted by relatively delaying the time corresponding to the constant interval. Demodulating means for outputting in parallel the first reproduced video signal and the second reproduced video signal, and a signal generation circuit for generating a switching signal based on the output detection signals of the first and second detectors, A first memory that stores the first or second reproduced video signal and reads it as a reproduced video signal of the one line; and a second memory that stores the second or first reproduced video signal and reproduces the other line As a video signal A second memory for reading, a reproduced video signal of the self-recording / reproducing portion of the first track which is reproduced at high speed by the first head output from the demodulating means, and is reproduced at high speed by the second head. The reproduced video signal from the first track and the reproduced video signal from the second track reproduced at high speed by the first head are selected based on the switching signal and input to the first memory. A reproduction signal of a self-recording / reproducing portion of the second track reproduced at high speed by the second head, a reproduction signal from the second track reproduced at high speed by the first head, Switching means for selecting a reproduction signal from the first track reproduced at high speed by the second head based on the switching signal and inputting it to the second memory; And a synthesizing unit for synthesizing the reproduced video signals read from the second memory in time series to obtain a high-speed reproduced video signal.