JPH01235488A - Video recording/reproducing device - Google Patents

Abstract

PURPOSE:To obtain a good picture free from a noise bar by interpolation- processing and outputting a part above a prescribed amplitude among the reproduced video signals of prescribed fields as the video signal of one field portion at the time of reproducing a recording medium while running at the prescribed speed. CONSTITUTION:In a case that the signal that the video signal of one field is segment-recorded after being divided into l-pieces (l is integer 2 or more) of tracks is reproduced a recording medium while running at the speed n-times as fast as the speed at the time of recording, and a part of the prescribed amplitude among the reproduced signals of m-fields (m is integer 1 or more) portion is interpolation-processed and outputted as the video signal of one field portion, a value (n) is selected so as to satisfy an expression I. The value (k) in the expression I represents an optional integer. When the value (n) is selected in such a way, since the part above the prescribed amplitude not become the noise bar among the reproduced signals in the respective fields appears complimentarily, the interpolation processing can be performed by using these parts. Thus, the good picture free from the noise bar can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a device for recording and reproducing video signals using a rotary head, and particularly to a video recording and reproducing device using a segment recording method.

(Prior Art) A segment recording method is known as a method for recording a wideband video signal such as a high-definition television signal. In this method, when video signals are recorded on diagonal tracks on a recording medium using a rotating head, as in a VTR, one field of video signal is divided into multiple tracks and recorded, and one track The unit of video signal recorded in the video signal is called a segment.

Generally, in a VTR, when performing high-speed reproduction by running the recording medium at a faster speed than during recording, it is not possible to obtain a good image without noise bars by simply extracting the reproduction signal from the head. Therefore, in a general VTR using a non-segment recording method in which fields are recorded on one track, for example, as described in Japanese Patent Application Laid-open No. 80-117885, between fields (odd fields and By performing interpolation (between even fields), a good image is obtained. however,
Even if this high-speed playback technique in the non-segment recording method is applied to the segment recording method, it is of course impossible to produce a correct image (1).

(Problems to be Solved by the Invention) As described above, in conventional segment recording type VTRs, when recording a recording medium at a faster speed than when recording in 11i,
There was no technology to obtain good images without noise bars.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video recording and reproducing apparatus that can obtain good video when a video signal recorded by the segment recording method is played back by running a recording medium at a higher speed than during recording.

[Structure of the Invention] (Means for Solving the Problems) The present invention divides one field of video signal into one track (e is an integer of 2 or more) and records the segmented signal. Playback is performed while running the recording medium at n times the speed, and a portion of a predetermined amplitude of the reproduced video signal of m fields (m is an integer of 1 or more) is interpolated and output as a video signal of 1 field. In this case, a good image with few noise bars can be obtained by selecting n as n-(2,i'-±1)7m (k is any integer).

(Function) If the value of n is selected as described above, the parts of the reproduced video signal that do not become noise bars and have a predetermined amplitude or more will appear complementary between each disc, so these parts can be used for interpolation processing. If you do this, you will get a good image with almost no noise bars.

(Example) The present invention will be explained in detail below.

FIG. 1 is a block diagram showing the configuration of main parts on the playback side of a video recording and playback apparatus according to an embodiment of the present invention.

In FIG. 1, the input terminal 10 is connected to a rotary head 25, 26 on a head drum 24 provided in the path of a recording medium (magnetic tape) 23 from a supply reel 21 to a take-up reel 22 shown in FIG. A video signal reproduced by is input. This video signal is input to the reproduction circuit 11, where it is amplified and A/D converted.

Further, the reproduced video signal that has passed through a part of the reproduction circuit 11 (for example, an amplification section) is also input to the level detection circuit 12, and its level, that is, the envelope amplitude is detected. The level detection circuit 12 determines whether the reproduced video signal is a signal that can be correctly reproduced depending on whether the reproduced video signal has a predetermined amplitude or more, and outputs a memory write enable signal WE in accordance with the determination result. This memory write enable signal WE is a signal that inhibits a write operation of the field memory, which will be described later.

A reproduced video signal consisting of a digital signal output from the reproduction circuit 11 is distributed to the first to third field memories 14, 15, and 16 via the selector 13. The selector 13 is controlled by the memory controller 17 as to which field memory the reproduced video signal is supplied to, and the field memories 14, 15, and 16 are controlled by the memory controller 1.
7 controls the write/read mode. However, when the field memories 14, 15, and 16 are supplied with the write enable signal from the level detection circuit 12, they become write-inhibited even if they are set to write mode by the memory controller 17.

The selector 18 selects only the output of one of the field memories 14, 15, and 16 that is set in read mode by the memory controller 17, and outputs it to the terminal 19.

FIG. 3 shows the control states of the first to third field memories 14, 15, and 16 by the memory controller 17, and the three states 1, 2, and 3 are switched for each field of the reproduced video signal. . To explain the operation of the first field memory 14 using FIG. 3, first, in state l, the reproduced video signal of the first field is
All are written in. In the next state 2, of the reproduced video signal of the (i+1)th field, the part of the noise bar that is not correctly reproduced as an image is not written to the field memory 14 according to the memory write enable signal WE output from the level detection circuit 12, and the level detection Only the portion determined by the circuit 12 to have a predetermined amplitude or more is stored in the field memory 14.
written to.

And the next state! In r33, when the reproduced video signal of the (i+2)th field is being manually input, the contents of the field memory 14 are read out and sent to the terminal 1 via the selector 18.
Output to 9.

In this way, out of two consecutive fields of reproduced video signals, a portion of a predetermined amplitude or more that does not become a noise bar is 1
It is interpolated as a field video signal and output from the terminal 19.

Second. Also in the third field memory 15.16,
It is controlled by the memory controller 17 to prevent duplication of operations with other field memories as shown in FIG. ! Writing is performed in any of states 1 to 3, and reading is performed in other states.

Here, as a specific example, the running speed of the recording medium is 7/2 times that of recording, that is, in the equation for n, e-3, m
FIG. 4 shows the locus of the rotary head during reproduction in the case of -2, k-1. The playback envelope (envelope of the playback video signal) at this time is as shown in Figure 5, and if this is represented on the screen by associating the position on the screen with the segment as shown in Figure 6, it is shown in Figure 7. It comes to show. Fifth
In the figure, the shaded area is a part of the reproduced video signal whose amplitude is less than a predetermined value, and the shaded area in FIG. 7 represents the part of the noise bar corresponding to the shaded area in FIG. 5.

As is clear from FIG. 7, the parts where the noise bar 5 appears are reversed in the first and second fields, in other words, the parts where the noise bar does not appear are complementary.

Therefore, using the circuit shown in FIG. 1, of the reproduced video signals of the first and second fields, only the portions determined by the level detection circuit 12 to have a predetermined amplitude or more are used for interpolation processing as a video signal of one field. In principle, a good image without noise bars can be obtained.

In the above embodiment, explanation was given using 7/2x speed playback as an example.
A similarly good image can be obtained by performing n-times speed reproduction that satisfies the following formula (% formula 1) (k is any integer). This equation (1) is derived as follows.

That is, when one field is divided into tracks and recorded, interpolation processing is performed using a portion of the reproduced video signal for one m field having a predetermined amplitude or more, and the video signal for one field is constructed. Since equal video information is required in 9 segments, it is necessary for the playback envelope to have a period T of T-m/I (field) (2) as shown in Figure 8. It is. In FIG. 8, as in the case of FIG. 5, m-2 (field) 1. The case of r-3 (track) is shown. For example, in Figure 5, two consecutive scan periods are one period of the playback envelope, and one
Since the field consists of three segments, the playback envelope period is m/, e-2/ as shown in Figure 8.
There will be 3 fields.

At this time, n is n-(A/m)+l...(3)
becomes. Here, A is the number of tracks passed when the rotary head scans the recording medium m times, and when A is an integer, the above period T is obtained.

Generally, when playing back a video signal recorded using the segment recording method in which one field is made up of e track segments at standard speed (same speed as when recording), the 9th
As shown in the figure, segments 1, 2 .・
The video signals of segments 1, 2, . . . of the second field are sequentially reproduced after the video signals of segments 1, 2, .

Note that the arrows in Fig. 9 should be reversed to show the segments.

No 1. ...may be played back in the order of the first segment.

Even when performing n-times speed reproduction, the conditions for obtaining a correct image are the same. That is, when performing n-times speed playback, as shown in FIG. 10, no blocks of the playback envelope with a period T appear within the m field period, so the segments at the corresponding positions of these playback envelope blocks are , as shown in the figure, the first segment of the odd field as in the case of standard speed playback in FIG.

The second segment, . . . second segment, the first segment of the even field, the second segment, . . . the first segment may be reproduced in sequence.

A at this time is A-2i・km±1 −(4).

Therefore, n is n-(A/m)+1 = f (2,i' ・k-m±1)/ml+1- (
2J!・k±1)7m ...(5),
It is the same as equation (1).

[Effects of the Invention] According to the present invention, a video signal of one field is divided into segments and a signal recorded in segments is reproduced at n times speed, thereby producing a reproduced video signal of m fields of 1 minute (m is an integer of 1 or more). When interpolating and outputting a portion of a predetermined amplitude as a video signal for one field, n is set to n-(2,i'・
By selecting the conditions of k±1)7m, parts of the reproduced video signal that do not become noise bars and have a predetermined amplitude or more appear in a complementary manner in each field, and by performing interpolation processing using these parts, You can get good images with almost no noise bars.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of main parts of a video recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a tape running system and a rotary head mechanism for the same signal, and FIG. A diagram for explaining the control procedure of the field memory in the embodiment, FIG. 4 is a diagram showing the rotary head trajectory on the magnetic tape during 7i double speed playback in the same embodiment, and FIG. 5 is a diagram for 7i double speed playback in the same embodiment. Fig. 6 is a diagram showing the correspondence between each segment and the position on the playback screen in the same embodiment, and Fig. 7 is a playback screen corresponding to Fig. 5. The diagrams schematically showing the above display state and FIGS. 8 to 10 are diagrams for explaining the present invention in detail. 10... Playback video signal input terminal, 11... Playback circuit, 12... Level detection circuit (amplitude detection means), 13.
...Selector, 14-16...Field memory, 1
7...Memory controller, 18...Selector, 1
9...Output terminal. Applicant's agent Patent attorney Takehiko Suzue District 1, No. 2, Figure 8, Figure 9

Claims (1)

[Claims] A recording medium is moved in the longitudinal direction, and a rotary head is used to
In a video recording and reproducing apparatus that divides a field video signal into l tracks (l is an integer of 2 or more) and records and reproduces the same, means for performing reproduction while running the recording medium at n times the recording speed. and a means for detecting the amplitude of the reproduced video signal obtained by this means; and a means for detecting the amplitude of the reproduced video signal obtained by this means, based on the amplitude detection result obtained by this means, and a means for interpolating and outputting a portion larger than the amplitude as one field worth of video signal, and n satisfies the following formula n=(2l·k±1)/m (k is any integer). Features of video recording and playback device.