JPH02288568A - Signal processor - Google Patents

Abstract

PURPOSE:To reproduce a picture in detail by converting a reproducing signal into a standard signal at special reproduction for a helical scan VTR. CONSTITUTION:The processor is provided with a signal generator 38 counting a horizontal synchronizing signal obtained by a synchronizing signal generator 38 in the case of reading a signal from a field memory device 44 and resetting the result with a vertical synchronizing signal every other period to generate a memory control signal to read a 263H field and a 262H field alternately and generating a gate signal representing the field period, and a signal processing circuit to add the video signal obtained from a field memory device 44 and an output signal of a 1H delay line 45. Moreover, the processor is provided with a switch circuit 47 switching an output of the field memory device 44 and an output of the signal processing circuit for each field, and a synchronizing signal replacing circuit 48 replacing only the vertical synchronizing signal into the vertical synchronizing signal obtained from the synchronizing signal generator 38. Thus, even when the signal is in the slow still mode, the signal is converted into the standard signal and the picture is reproduced in detail.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a slow still image suitable for correcting the difference in the signal format of the reproduced signal from the standard format during special reproduction in a VTR, that is, when reproducing slow motion still images. The present invention relates to a signal processing device.

In a conventional so-called helical scan type VTR, information is recorded in diagonal tracks on a magnetic tape in units of fields, as shown in FIG. Adjacent tracks are recorded so that the horizontal synchronization signal positions match. This is usually called H-alignment (H means horizontal synchronization signal), and this allows the horizontal synchronization of the reproduced image even when the tape is stopped and a still image or the tape is intermittently fed to obtain a slow-motion image. Continuity of signal phase is maintained. However, the number of horizontal synchronizing signal periods in one field of the reproduced image at that time (tVH8, V
TR(7) 2648 in standard mode. 263 in 3x mode
It becomes H.

In other words, as shown in FIG. 5, when video tracks 2, 3, 4.5 are recorded on a magnetic tape 1, when reproducing them, the rotary head is moved in the direction of arrow 6 at the same speed as when recording. Scan the track in direction 7. In order for the rotary head to precisely scan the tracks 2, 3, 4, and 5, the running speed of the tape 1 is controlled by reproducing the control signal 8.

Problems to be Solved by the Invention On the other hand, when the running of the tape 1 is stopped, the broken line 9 in FIG.
This results in a rotating head trace as shown in . In this case, the track width of the reproducing head is the same as that of the recording track, but if a wide head as shown by the two-dot chain line 10 is used, it is possible to reproduce almost track 3.

As shown in FIG. 6, the rotary head is arranged such that the gap between the rotary magnetic heads 11 and 12 is located at the intersection of the circumference and a straight line passing through the center of the disk on the rotary head disk. Also, the gap of the magnetic head is the enlarged chip part 13.1 seen from the front of the magnetic head (contact surface with the tape).
4, the gap portions 16 and 17 are not perpendicular to the scanning direction (they have an azimuth).
The tilt head 14 is tilted α to the left (α is 6 in VH8).
°). Therefore, the recording pattern is formed in tracks where magnetic patterns are adjacent to each other, as indicated by diagonal lines in FIG. This method avoids crosstalk between adjacent tracks.

If track 3 is recorded by the magnetic head 11 (=chip 13), then track 3 can only be reproduced by the magnetic head 11. In the still state where the magnetic tape is stopped, the head 11 traces the broken line 9 as described above, so there is no output at the beginning of scanning one track.

(To scan the lower part of the track 4 with different azimuths.) The output state of the head is shown in FIG. 7(a). In this way, when the tape is stopped, the head output drops considerably in some parts. To prevent this, the chip 13 shown in FIG.
If a head having a track width wider than the video track width as shown by the dotted line is used, a head output as shown in FIG. 7(b) can be obtained. (The trace width widens to the dotted line 10 in FIG. 5.) However, in this figure, the head 12 also has the same azimuth as the head 11, as shown in the chip 15 in FIG. 6(d) (a wide head up to the dotted line). This is the envelope when using . That is, at the head 12, there is a chip 1 having the same azimuth as the original recording/reproducing head 12 and the head 11.
This is possible by attaching two heads (No. 5). Now, in this case, the 1 traced by Rad11
As mentioned earlier, the horizontal synchronization signal recording parts of adjacent tracks match the field signal, so the reproduced signal is 264H long at VH8 standard speed, and 263H long in 3x mode. Become. When viewing this on a television receiver, the raster is clearly visible without any interlace. The present invention seeks to eliminate such drawbacks.

Means for Solving the Problems The present invention provides data for approximately one field of a video signal, that is, NTSC.
field memory device that can store 263H (313H for PAL, where H is the horizontal synchronization signal period) and the horizontal and vertical synchronization signals (262,5H for video signals).
When reading signals from the field memory device and the synchronization signal generator that generates the period, the horizontal synchronization signals obtained from the synchronization signal generator are counted and reset with every other vertical synchronization signal (frame synchronization signal). By doing so, 263H (313H for PAL), 262H (312H)
H), 263H (313H), 262H (312H)・
2638 (313H) field and 26 like...
28 (312H) memory control signal for alternately reading fields and the above 263H (313H), 262
A signal generator that generates a gate signal indicating an H (312H) field period and a video signal obtained from the field memory device are delayed by a 1H delay line so that the signal amplitude of the input signal and the output signal of the delay line are the same. a signal processing circuit that adds the input signal and output signal of the delay line and adjusts the amplitude to obtain a video signal having the same amplitude as the input signal of the delay line; the output of the field memory device; and the output of the signal processing circuit. and 263 obtained from the above signal generator.
H (313H).

The gate signal indicating each field period of 262H (312H) switches each field to 263H.
(313H) field period, the signal obtained from the field memory device is obtained as an output, and 262H (31
2H) The field period includes a switch circuit that obtains the signal obtained from the signal processing circuit as an output signal, and synchronization that replaces only the vertical synchronization signal of the video signal obtained from the switch circuit with the vertical synchronization signal obtained from the synchronization signal generator. This is a signal processing device having a signal exchange circuit.

As mentioned above, the reproduced signal during still and slow motion in a home VTR is a non-interlaced signal, that is, in the case of VH3, one field is a 264H signal in the standard mode, and 263H in the triple mode. A method is provided in which a so-called reproduced signal is converted into a standard signal by passing it through the signal processing device of the present invention. The slow and still playback signals of a normal home VTR can be transferred directly to another VTR.
Since the recorded signal is not a standard signal as described above, the recording phases of horizontal synchronizing signals of adjacent tracks shown in FIG. 5 will be different. The length of one field of the slow and still playback image of the recording tape is 265.5H (standard mode) and 263.5H (3x mode), and there is a horizontal scanning phase difference of 0.5H for each field. .

When this signal is applied to a TV receiver and the image is viewed, an extreme curvature appears at the top of the screen. This is usually called skew.

The present invention improves this point as well. That is, even slow and still signals can be converted into standard signals if they are passed through the signal processing device of the present invention.

Embodiment FIG. 1 is a mechanical part and block diagram showing an embodiment of the present invention. In FIG. 1, the same numbers are used for blocks or mechanical parts that are the same as those explained up to FIG. 7.

In FIG. 1, the tape 1 is supplied from a supply reel (not shown) and wound around the rotating head disk 10 and the stationary cylinder 20 via the guide ball 21, and the tape moves diagonally along the lead 50. . Tape running is driven by capstan 26. The pinch roller 27 moves the tee 11 in the direction of the arrow 6. The above-mentioned rotary magnetic heads 11 and 12 are attached to the rotary head disk, and during reproduction, tracks recorded on the tape are tracked by the control system described below. As shown in FIG. 5, the magnetic tape 1 has video tracks 2, 3, . . . and a track on which a control signal 8 is recorded. In order for the magnetic head to scan this video track 2.3..., the rotational speed and phase of the rotating magnetic head are controlled, and the rotation of the capstan is controlled, and the tape
It is necessary to control the running of the vehicle.

As shown in Fig. 6, since one field corresponds to a half-circle of the disk, the rotating head magnetic disk 10 is synchronized with a reference signal equal to the frame frequency (2 fields) of a so-called television signal, and the capstan is also used to record data on the tape. It is necessary to adjust one phase in synchronization with the reproduction signal of the control signal. The reference signal is obtained, for example, by dividing the signal of the oscillator 35 that oscillates at a frequency four times the color subcarrier frequency (fsc). The frequency of the NTSC synchronization signal is 2 in the relationship between the horizontal synchronization signal frequency (fu) and the color subcarrier.
fsc=455fH...(1), frame frequency 1p=1/2 field frequency (fpt)=f
From the relationship o1525, 4fsc=455X525fr
t therefore fri=2fy=Yo'SO=' 4 f
SC..., (2) 455x525 238.875 In other words, dividing the 4fsc oscillator signal by 238.875 gives the field frequency.

The oscillator 35 in FIG. 1 generates a reference signal with a frequency of 4 fsc, which is divided by 238.875 in the frequency divider 37, and then the vertical synchronization signal (field frequency signal) is output from the divider 37.
is obtained. Then, this signal is further divided into 1/2 by a frequency divider 39.
If the frequency is divided by , the frame frequency becomes a rotation reference signal for the rotary head disk 10 and a control reference signal for the capstan. The relationship between these signals is as shown in FIG.

Figure 2(a) shows the output of the branching unit 37, which is 59.94H.
z vertical synchronization signal. As mentioned above, this is 1/2
From the relationship fr;=fo 1525, the vertical synchronization signal period T
v becomes 262.58. H is the horizontal synchronization signal period.

In other words, H=earth H Tv = '=-'-"x-'-= 262, 58
-(3) frl 2 fHI.

Now, if the vertical synchronization signal is added to the 172-minute period 39, the signal shown in FIG. 2(b) is obtained.

On the other hand, a magnet 12 is attached to the rotary head disk 10 and corresponds to the position of the rotary head 11 for indicating the rotational phase of the rotary magnetic head, and a fixed pickup 23 is located on the rotational orbit of the magnet 12. This positional relationship is as shown in the top view of the rotary head drum in FIG.

In this positional relationship, the signal obtained by amplifying the output of the pickup 23 by the amplifier 30 is as shown in FIG. 2(C). Next, the signal of the 1/2 frequency divider shown in FIG.
is added to the drive circuit 41 of the drive motor 25. As a result, phase comparator 40 → drive circuit 41 → drive motor 25 → motor shaft → magnet 2 of disk 10
A phase control loop of 2→pickup→amplifier→phase comparator 40 is formed. Therefore, the above reference signal (Fig. 2(b)
)) The rotational phase of the rotating head matches.

On the other hand, the reference signal of the 1/2 frequency divider 39 (FIG. 2(b)
) is supplied to the pulse delay circuit 34, and as shown in FIG. 2(e), a signal in which the rising edge of FIG. 2(b) is delayed by TD is obtained. Furthermore, this signal is applied to a phase comparator 33. On the other hand, the control signal 8 shown in FIG. 1 is recorded on the magnetic tape.

(This signal is recorded with a constant phase relationship with the recording of video tracks 2, 3, 4, . . . ) This signal is reproduced by the fixed magnetic head 29 as the tape runs. The reproduced control signal is amplified by an amplifier 31 and applied to a phase comparator 33. Therefore, since the signal shown in FIG. 2(e) is also added to the phase comparator 33, a phase error signal of both signals is obtained, and the capstan motor 28
is added to the drive circuit 32 of. Therefore, phase comparator 3
A phase control loop such as 3-drive circuit 32→capstan motor 28→capstan 26→pinch roller 27→magnetic tape 1→fixed magnetic head 29→amplifier 31→phase comparator 33 is formed. Therefore, the above delay time T
By adjusting D, the rotating magnetic heads 11 and 12 can completely trace the video track.

When tracking is performed in this manner, a mixed signal of an FM luminance signal and a subcarrier modulated (629 KHz subcarrier in the case of VH5) color signal is obtained from the rotating magnetic heads 11 and 12. A rotary transformer 19 is usually used to extract this from the rotating body. The reproduced mixed signal passes through one rotary transformer, is amplified by a preamplifier 42, is demodulated by a signal processing circuit 43, and is obtained from a terminal 51 as a reproduced video signal. normal VTR
applies this output to a TV receiver to view the reproduced image.

Now, the signal processing circuit according to the present invention is not used for normal playback (slow and still playback). During still playback, the tape stops as described above and the signal processing occurs as shown by the broken line in Figure 5. It is possible to stop the tape at such a tape position based on the above control signal playback position.The control system for this is not directly related to the present invention and will therefore be omitted.

Also, slow playback can be made into slow motion with variable speed by instantly transitioning tracks and controlling the amount of time the track is stopped in still mode. In other words, slow playback can be said to be still playback that divides time.

Now, during still shooting, as mentioned above, on VH3, the playback signal is 1
The field signal is 264H in standard mode,
In 3x mode, it becomes 263H. This signal is obtained at terminal 51. The signal processing method according to the present invention will be described below. The video signal obtained from the signal processing circuit 43 is applied to a field memory device 44. This field memory device usually stores digital signals after converting them into digital signals. Here, we will introduce an analog to digital converter (A/D) or a digital to analog converter (D) for this purpose.
/A) etc. are not shown, but are assumed to be included in this field memory device 44. Furthermore, this field memory device is a so-called fast-in/fast-out type memory in which reading and reading clocks can be handled separately.

Sampling frequency (=clock frequency) f with bit accuracy when converting an analog video signal to digital/analog
Suppose you did it in c. The memory configuration in this case is as follows. In other words, if one memory cell unit is formed for each bit corresponding to each bit, and one unit is stored horizontally for each horizontal line (as will be explained later), then as shown in FIG. It becomes like this. Figure 3 shows
5 is an enlarged view of the main part of FIG. 4 showing one screen and its waveform. FIG.

k=8. When fc=13.5MHz, 858 memory cells are required for one horizontal line, and 26 memory cells are required for vertical line.
If there are three lines, one field of screen can be stored in memory. In order to read and write to this memory, it can be seen from the above points that it is sufficient to add a clock for writing and reading, a signal for controlling the scanning timing for each line, and the start point of one image.

A description will be given of how a video signal during still shooting is stored in the field memory device. As described above, the video signal obtained from the signal processing circuit 43 is applied to the field memory device 44 and also to the synchronization separation circuit 5.
It can also be added to 2.

In the synchronization separation circuit 52, a horizontal synchronization signal is extracted from the video signal and applied to the field memory device 1t44 and the clock generator 53. Furthermore, the synchronous separation circuit 5
2 to the vertical synchronization signal separator 56.
added to. Here, only the vertical synchronization signal is extracted and applied to the field memory device 44. Therefore, since the field memory device 44 is supplied with a signal for controlling the memory as described above, the memory cells within the memory are connected to each other.

is converted into a signal for scanning and a single image is captured. Since the signal processing circuit 43 always outputs a video signal, the system controller 55 of the magnetic recording/reproducing device supplies a timing signal and a command signal to the field memory device to memorize only one required image. A method for reading signals stored in the field memory device in this manner will be described below.

For reading, it is the same as for writing, and there may be a lock signal, a read start timing signal for each line (corresponding to a horizontal synchronizing signal), and a single image read timing signal (corresponding to a vertical synchronizing signal). First, the read start signal for each line is sent from the oscillator 35 to the frequency divider 36.
A signal corresponding to the horizontal synchronization signal obtained through As mentioned above, from the relationship of equation (1), this signal is 4f
It can be obtained by dividing the oscillator output of sc by 910.

In addition, the image readout timing signal for - sheets is obtained by dividing the horizontal synchronizing signal of the frequency divider 36 by 263 for one field and by 262 for the other field, as shown in Fig. 2 (g).
) is obtained. This signal is obtained by a signal generator 38. The signal generator 35 also receives the horizontal synchronizing signal from the frequency divider 36 and the frame signal from the 1/2 frequency divider 39 (see FIG. 2(b)), resulting in the 263H signal.

262H, 263H, 262H . . . obtain start timing signals of the field memory device 44 with cycles. Also, the read clock signal is passed through the frequency divider 36 as in the case of writing.
The clock signal is applied to a clock generator 54 which generates a clock n times as large as the horizontal synchronization signal, and the clock signal obtained here is applied to the field memory device. Therefore, reading is independently controlled by the control signal generated by the reference signal obtained from the oscillator 35.

The thus obtained video signal from the field memory device 144 is added to a 1H delay 41145 where it is delayed by one horizontal opening signal period. The delayed video signal is applied to mixer 46. The output video signal from the field memory device 44 is also added to the mixer 46, where both signals are mixed at the same signal level. The obtained video signal is adjusted to the same level as the signal obtained from the field memory device. The signal obtained from this mixer 46 has the following meaning. Consider, for example, a case where a diagonal white band 66 is projected on the monitor television 59 in FIG. 4(a). If we look closely at the points where one scanning line 60 and the next scanning line 61 intersect with the white band 66, line 60 intersects with point 67.68, and line 61 intersects with point 69.70.
intersect with If this is shown as a video signal, Figure 4 (■, (
C).

By the way, as mentioned above, one field of a still reproduction image of a VTR is 264H or 263H. This scans the same raster on the TV screen. In this case, the points 67 and 69 are positioned apart, so that they appear stepped on the screen as shown at 73.degree. 74 in FIG. In order to make this look smooth, an ink lace method is used. That is, scanning lines are interpolated for each field. With this method, line 6
During 0.61 63 will be scanned in the next field.

In a normal image, there is a signal corresponding to line 63, but in both still images, one field 264H (
or 263H) is a repetition of the same signal. Therefore, the present invention creates a signal corresponding to this line 63 by the 1H delay line 45 and mixer 46 as described above. FIG. 4(d) shows the signal. This signal is a signal obtained by adding a certain line and the next line to 1/2, and becomes a signal when scanning line 63 between lines 60 and 61.

Now, the signals of the field memory device are read out by exchanging the 263H field and 262H field. Therefore, the 263H field is an odd field, and the even field is the 1H delay line 45. mixture! ! ! If a video signal is generated as a signal passed through 46, it will be seen that the above-mentioned increment relationship is obtained. For this purpose, a switch circuit 47 is provided, and the output signal of the field memory device 44 and the output signal of the mixer 46 are added to the switch circuit 47, and the switch shown in FIG. Both signals can be switched using a control signal. However, the vertical synchronization signal of Increce is 262.5.
Since it is necessary to have an H period, it is necessary to replace the vertical synchronization signal output from the switch circuit 47. This circuit is the V synchronization switching circuit 48.

The vertical synchronization signal obtained from the frequency divider 37 is applied to the V synchronization switching circuit 48, where switching is performed.

A pseudo standard signal is obtained at the output terminal 49.

The present invention is generally capable of converting a playback signal during special playback of an edge scan VTR into a standard signal. During special playback on a helical scan VTR, in addition to the above-mentioned slow still, playback at 2x, 3x, . . . up to n times is possible. At that time, the number of horizontal synchronizing signal lines between one field is doubled, 261H, 13 times, 258H, 14 times, 255H, and so on. Even in this case, the present invention can be applied, and if the number is small, there will be a portion without a screen, but the signal will be converted to a standard signal.

Effects of the Invention The present invention is a signal processing method for converting the signal format of a playback signal into a standard signal during slow still operation in a helical scan type VTR, which enables reproduction of a fine-grained image when viewing the playback screen on a TV screen, as well as the output signal of the main output signal. This is a highly effective signal processing device that can be recorded as a standard signal even if it is dubbed, and when it is played back, it does not produce skew distortion, etc., as in the case of conventional signals.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a signal waveform diagram of the main part in the block diagram of FIG. 1, FIG. 3 is an enlarged view of a TV screen for explaining the embodiment, and FIG. Figure 4 is T
V screen diagram and waveform diagram, Figure 5 is a helical scan type V
A tape pattern diagram of the TR, FIG. 6 is a plan view and a front view of a main part of a rotary head disk, and FIG. 7 is an envelope waveform diagram of the head output during still operation. 33... Phase comparator, 34... Delay circuit, 35... Oscillator, 36... Frequency divider, 37... Frequency divider device, 38... signal generator, 39... frequency divider, 40... phase comparator, 41... drive, 43...・Signal processing, 44...Field memory device, 4
5...1H delay line, 46...mixer,
47... Switch circuit, 48... Synchronous exchange, 52... Synchronous separation, 53.54...
... Clock generator, 56 ... Vertical synchronization separation. Name of agent: Patent attorney Shigetaka Awano and 1 other famous person: 1.

Claims (2)

[Claims] (1) A field memory device that can store about one field of the video signal, that is, 263H in NTSC (313H in PAL, where H is the horizontal synchronization signal period), and a horizontal synchronization signal of the video signal from the reference clock generator signal. A synchronization signal generator generates a vertical synchronization signal (262.5H cycle), and when reading signals from the field memory device, counts the horizontal synchronization signals obtained from the synchronization signal generator and generates every other vertical synchronization signal. By resetting with (frame synchronization signal), 263H (
PAL is 313H), 262H (312H), 263H
263 like (313H), 262H (312H)...
A signal generator that generates a memory control signal for alternately reading the H (313H) field and the 262H (312H) field, and a gate signal indicating the 263H (313H) and 262H (312H) field periods, and the field memory device. The resulting video signal is delayed by a 1H delay line, the input signal and output signal of the delay line are made the same signal amplitude, and the input signal and output signal of the delay line are added together and the amplitude is adjusted to achieve the delay. 263H (313H), 2 which is obtained from the signal generator by a signal processing circuit that obtains a video signal with the same amplitude as the input signal of the line, the output of the field memory device, and the output of the signal processing circuit.
A gate signal indicating each field period of 62H (312H) is used to switch each field to 263H (263H).
During the 313H) field period, the signal obtained from the field memory device is taken out as an output, and the 262H(
312H) The field period is a switch circuit that can take out the signal obtained from the signal processing circuit as an output signal, and synchronization in which only the vertical synchronization signal of the video signal obtained from the switch circuit is replaced with the vertical synchronization signal obtained from the synchronization signal. A signal processing device comprising a signal switching circuit. (2) The field memory device is composed of a read-out type memory in which the write clock signal and the read clock signal are handled asynchronously, and when writing the video signal of the reproduced still image, it is synchronized with the horizontal synchronization signal of the video signal of the reproduced still image. Memory writing is controlled by a clock signal, and reading from the memory is controlled by a clock signal synchronized with the horizontal synchronization signal from the synchronization generator, and the phase of the horizontal synchronization signal of the video signal read from the field memory device is controlled. 2. The signal processing device according to claim 1, wherein the signal processing device is continuous.