JPH04318318A - Vtr - Google Patents

Abstract

PURPOSE:To always easily watch a picture even under a high speed picture search. CONSTITUTION:A regenerative video signal from an input terminal 1 is taken out through a selector 2 to an output terminal 3, and is also supplied to an adder 4. Then, a detecting signal of a noise bar from a terminal 5 where the detecting signal of the noise bar is supplied is supplied to a control circuit 6, and a control signal from this control circuit 6 is supplied to the selector 2, and is also supplied to the adder 4. Then, by a feedback of an adding output to an input of this adder 4, the regenerative video signal from the terminal 1 is accumulated in order, and this adding output is supplied to a level deciding circuit 7 where an average level of this accumulated signal is decided in accordance with the adding output, and then this decided level signal is supplied to the selector 2, so that this selector 2 is changed over to the side of the deciding circuit 7 during a period of the noise bar in accordance with the control signal from the control circuit 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VTR that performs recording and reproduction using a rotating head.

0002

2. Description of the Related Art For example, consumer VTRs are required to perform a so-called high-speed picture search. However, in this case, for example, in a VTR in which the azimuth angle of the recording/reproducing head is alternately changed for the recording track on the tape, each head reproduces signals from tracks with different azimuth angles during high-speed picture search. As a result, so-called noise bars occur, resulting in an extremely difficult-to-see image.

That is, FIG. 3 shows how a high-speed picture search is performed. Note that in this figure, each track is drawn vertically for explanation. With respect to such a recording track, A in the figure shows the scanning locus of the head during a high-speed picture search at an odd-numbered speed, for example, 3x speed, and B in the figure shows a high-speed picture search at an even-numbered speed, for example, 4x speed. In these figures, the azimuth angle of head A is +
, the azimuth angle of head B is -, and if the azimuth angle of the head when recording each track is as shown in the lower column, then each head A and B will be able to record the parts shown with diagonal lines in the figure. Only the signal will be extracted.

[0004] Therefore, signals in the portions not marked with vertical lines are not reproduced from each head A and B, and these portions become noise bars. As is clear from the figure, the position of the noise bar is fixed in odd-numbered high-speed picture search. On the other hand, in high-speed picture search at even multiple speeds, the noise bar and the image are played back alternately. However, in either case, the noise bar is visually noticeable, and the image quality is significantly degraded due to the noticeable noise.

[0005] In a VTR whose head has a constant azimuth angle, a guard band is provided between each track, and a similar noise bar is generated by this guard band.

[0006]

SUMMARY OF THE INVENTION The problem to be solved is that when a high-speed picture search is performed using a conventional device, noise bars occur and the image becomes extremely difficult to see.

[0007]

[Means for Solving the Problems] The present invention provides a VTR that performs recording and playback using a rotary head, in which a playback signal (input terminal 1) is transmitted when the tape is transported at a higher speed than during recording and played back. This VTR is designed to replace (selector 2) a missing portion with a signal corresponding to the average luminance level (adder 4, level determining circuit 7) of a portion that has a strong temporal and spatial correlation with the missing portion.

[0008]

[Operation] According to this, by replacing the missing part in the reproduced signal with a signal corresponding to the average brightness level of the part with strong spatiotemporal correlation with the missing part, the image is always easy to see even during high-speed picture search. can be made into something.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of the main parts. In this diagram,
Reference numeral 1 denotes an input terminal to which a reproduced video signal demodulated from a signal reproduced by heads A and B (not shown) is supplied. The reproduced video signal from the input terminal 1 is taken out to the output terminal 3 through the selector 2. At the same time, this input terminal 1
A reproduced video signal from the adder 4 is supplied to the adder 4.

Reference numeral 5 denotes a terminal to which a noise bar detection signal is supplied; for example, a noise bar is detected from the amplitude level before demodulation of the signal reproduced by the above-mentioned heads A and B, and is supplied to the terminal 5. . The noise bar detection signal from this terminal 5 is supplied to the control circuit 6, the control signal from this control circuit 6 is supplied to the selector 2, and the control signal from this control circuit 6 is supplied to the adder 4. .

The adder 4 sequentially accumulates the reproduced video signal from the input terminal 1 during the period when the control signal from the control circuit 6 is supplied. That is, by feeding back the addition output of the adder 4 to the input, the reproduced video signal from the input terminal 1 is sequentially accumulated. The added output of the adder 4 is supplied to a level determining circuit 7, and the average level of the accumulated signal is determined according to the added output. This determined level signal is supplied to the selector 2. Furthermore, this selector 2 is switched to the decision circuit 7 side during the noise bar period in response to a control signal from the control circuit 6. As a result, the noise bar portion in the reproduced video signal is replaced with a signal corresponding to the average luminance level of a portion that has a strong spatiotemporal correlation with the noise bar portion.

FIG. 2 shows a timing chart. In this figure, A indicates a reproduced video signal supplied to the input terminal 1, and the portion marked with a broken horizontal line in the figure is a noise bar. The control circuit 6 outputs the following information to this reproduced video signal:
First, as shown in B of the same figure, a reset signal is generated several horizontal scanning lines before the noise bar, and an enable signal is generated several horizontal scanning lines before the noise bar, as shown in C of the same figure. These reset signals and enable signals are supplied to the adder 4. As a result, the adder 4 accumulates the reproduced video signals for the period of several horizontal scanning lines before this noise bar, this accumulated value is supplied to the level determining circuit 7, and the signal with the determined average level is sent to the selector 2. supplied to And this selector 2 has a control circuit 6
A signal corresponding to the period of the noise bar as shown in D in the same figure is supplied from
As a result, as shown in E in the figure, the noise bar part in the reproduced video signal is output to the output terminal 3 as a signal (corresponding to the average luminance level of the signal during the previous few horizontal scanning lines). The signal replaced by (shown with diagonal lines) is extracted.

Therefore, in this device, by replacing the noise bar portion with a signal corresponding to the average luminance level of the strongly correlated portion, the noise becomes less visually noticeable, thereby preventing deterioration of image quality. can.

[0014] Thus, according to the above-mentioned device, the reproduced signal (
High-speed Even in picture search, images can always be easily viewed.

[0015] In the above example, the average luminance level of the noise bar part is obtained using the signals of several horizontal scanning lines before the noise bar, but it is also possible to use not only the signals before the noise bar but also the several horizontal scanning lines after the noise bar. In this case, it is possible to obtain a more accurate average brightness level of the noise bar portion. In that case, an image memory is used to store the reproduced video signal until the several horizontal scan lines before and after the noise bar are accumulated and the average brightness level is determined, and when reading this memory, the reproduced video signal is determined. What is necessary is to replace it with the calculated average brightness level.

Furthermore, the average brightness level can be determined not only from several horizontal scanning lines before and after the noise bar, but also from the reproduced video signal of the corresponding portion of the adjacent track by performing a high-speed picture search at an even multiple speed. You may also do so.

Further, the present invention can be similarly applied to a noise bar using a guard band.

[0018] The above-mentioned embodiment also applies to current consumer VTRs.
Although the present application is not limited to such a 1 field = 1 track VTR, for example, the case where it is applied to an H
Segment recording for DTV (one field is recorded in two parts of the head)
It can be used in a wider range of applications, such as when recording in a format that involves more than scanning.

[0019]

According to the present invention, by replacing a missing part in a reproduced signal with a signal corresponding to the average luminance level of a part that has a strong spatiotemporal correlation with the missing part, even in high-speed picture search. It is now possible to make images easier to view.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an example of essential parts of a VTR according to the present invention.

FIG. 2 is a diagram for explaining the same.

FIG. 3 is a diagram for explaining high-speed picture search.

[Explanation of symbols]

1 Input terminal 2 Selector 3 Output terminal 4 Adder 5 Terminal to which the noise bar detection signal is supplied 6 Control circuit 7 Level determination circuit

Claims (1)

[Claims] [Claim 1] A V that performs recording and reproduction using a rotating head.
In TR, when playing back a tape by transporting it at a higher speed than during recording, a missing part in the reproduced signal is replaced with a signal corresponding to the average brightness level of a part that has a strong spatiotemporal correlation with the missing part. A VTR made like this.