JPH02141084A - High-definition television signal error correcting device - Google Patents

Abstract

PURPOSE:To attain a highly accurate correction by outputting a signal corrected in a field when it is outputted as a high-definition television (MUSE) signal, and correcting the section between the fields in a still area when the signal is restored to the high-definition television signal and then monitoring, etc., are executed. CONSTITUTION:The first error correction is executed before processing is executed by a MUSE decoder 15, when the signal is outputted as the MUSE signal such as the case of dubbing, editing, an output to the other MUSE decoder, the signal corrected by a first error correcting means 13 is outputted. When it is outputted for the monitoring, etc., after the restoration to the high-definition television signal, the error is corrected by the still area processing inside the MUSE decoder based on an error flag, and the animated area and the still area are corrected respectively by the first error correcting means 13 and a second error correcting means 18. Thus, the error can highly accurately be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an MU that records and reproduces high-definition television signals (MUSE signals) using the MUSE system.
This is a high-definition television signal error f1g in a digital recording/reproducing device for SE signals.

2. Description of the Related Art The MUSE method is a method for transmitting high-definition television signals using one channel of satellite broadcasting. This method compresses the baseband of a high-definition television signal with a wide band of 20 MHz to 8 MHz by multiplex sub-Nyquist sampling, and then frequency modulates the transmission band to one of the broadcasting satellites.
The channel width was kept to 27 MHz, allowing satellite broadcasting to be carried out on the same transmission channel as current broadcasting.

The sampling pattern in the MUSE method is as shown in FIG. 2, and the signal is compressed to one-fourth of the original band and transmitted.

On the other hand, on the receiver side, a MUSE decoder is used to
To restore the original high-definition television signal from the SE signal.

Here, the MUSE decoder has a frame memory and reproduces the image using all the sampling points of the four fields that have been transmitted, but regarding the points that are not transmitted as shown in Fig. 2, Reproduction is performed using a two-dimensional interpolation method. In this way, the original image can be completely reproduced for still images, but since the correlation between fields is low for moving images, if all four fields are used, the image quality will deteriorate. Therefore, to reproduce the moving image part, it is necessary to reproduce only from the currently sent sampling points for one field, without using the sampling points for four fields.

As a result, the transmission band of the moving image becomes narrower and the blur becomes noticeable.As a countermeasure, when the entire screen moves in parallel, such as during panning, the motion vector is transmitted and the difference between frames on the receiver side is Accurate interpolation is performed by correcting the position of sampling points during interpolation. With this method, in the case of parallel movement of the entire screen such as panning described above, it is possible to obtain a resolution comparable to that of a still image even though it is a moving image.

The MUSE method is a band compression method for high-definition television signals that is compatible with both still images and videos, but it also uses various control signals such as correction position information of sampling points related to still images and videos. is once per field,
It is superimposed and transmitted as digital information during the vertical blanking period, and the receiving side corrects the position of the sampling point by controlling the writing and reading addresses of the frame memory according to the control signal. As explained above, the MUSE system is a signal format that can broadcast high-definition television signals in a narrow band, so it can be used not only for television broadcasting using broadcasting satellites, but also for VTR,
It can also be applied to various recording and reproducing devices such as video discs. Here, a case will be considered in which a MUSE signal is recorded and reproduced in a digital recording/reproducing apparatus (hereinafter abbreviated as digital VTR).

FIG. 3 shows a block diagram of a reproduction system of a generally known digital VTR. Using Figure 3, digital VT
The operation during playback of R will be briefly explained.

A signal reproduced from the tape via the reproduction head l is amplified by a reproduction amplifier 2, and written to a memory 4 via a reproduction processor 3. The memory 4 is a memory for restoring the signal randomized by interleaving during recording, and the original signal is restored by writing to the memory 4 based on the address information added during recording and sequentially reading it out. be done. The error correction decoder 5 corrects errors in the reproduced signal due to dropouts and detects errors based on the error correction code added during recording, and corrects errors that cannot be corrected by the error correction decoder 5. In circuit 6, based on the error flag, interpolation is performed with neighboring correlated samples to make the error visually less noticeable. The modified reproduction signal is output from the output terminal 7.

Problems to be Solved by the Invention However, the above-described high-definition television signal error correction apparatus has the following problems.

When restoring the original high-definition television signal using the MUSE decoder, motion is detected and the MrWj method is switched between a still area and a moving area. Furthermore, in a still area, if the entire screen moves slowly, motion vectors are used to perform motion correction. If error correction in a digital VTR involves selectively employing intra-field and inter-field correction by performing motion detection, etc. in the same way as a decoder, field memory is required, resulting in a very large circuit size. Furthermore, when corrections are made only within the field, the accuracy of the corrections decreases.

Next, if corrections are made only with the MUSE decoder, the signal will be output without an error flag when it is output as a MUSE signal, such as by dubbing, editing, or outputting to another MUSE decoder. . Furthermore, not only correct samples but also error samples are used for interpolation of non-sample points, but if uncorrected error samples are used for interpolation, the image quality will deteriorate, so interpolation is performed without using error samples. This method is complicated to control.

In view of the problems of the prior art, the present invention has been developed to solve the problems of the prior art.
When correcting signal errors, errors are corrected accurately by using the processing inside the MUSE decoder that restores the original high-definition television signal from the MUSE signal, and the correction is also applied when outputting as a MUSE signal. An object of the present invention is to provide a high-definition television signal error correction device capable of outputting a high-definition television signal.

Means for Solving the Problems The present invention corrects errors in the playback signal of a digital recording and playback device that records and plays back a MUSE signal obtained by band-compressing a high-definition television signal. A first error correction means, a MUSE decoder that receives the MUSE signal corrected by the first error correction means and restores the original high-definition television signal, and utilizes processing of a still area inside the MUSE decoder. a second error correction means for correcting errors;
The signal corrected by the first error correcting device is adopted in the moving area, and the signal corrected by the second error correcting device is adopted in the stationary area to restore the high-definition television signal. This is a high-definition television signal error correction device.

Effect of the present invention With the above-described configuration, when correcting errors in the MUSE signal reproduced by the digital 1'R, the first error correction is performed before processing by the MUSE decoder, and the dubbing, editing, etc. When outputting as a MUSE signal, such as to a MUSE decoder, the signal corrected by the first error correction means is output. Next, when the MUSE decoder restores the signal to a high-definition television signal and outputs it to a monitor or the like, a second error correction is performed by static area processing within the MUSE decoder based on the error flag. here,
Since the processing results of the moving region and the still region are selectively adopted through motion detection, the first error correction means performs 11 corrections on the moving regions, and the second error correction means corrects the still regions. It will be done.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a high-definition television signal error (
1 is a diagram showing an example of a primary device; FIG. In FIG. 1, 8 is a playback head, 9 is a playback amplifier, 10 is a playback processor, 11 is a memory for restoring data randomized by interleaving to its original form, and 12 is for error correction and error detection of the playback signal. Error correction decoder 1
3 is an error correction circuit that corrects error samples based on the error flag (broken line), and 14 is an output terminal for the MUSE signal.

Next, 15 is a MUSE decoder that restores the original high-definition television signal from the MUSE signal, and 16 separates audio, information signals, control signals, motion vector signals, and video signals from the input reproduced MUSE signal. Separation circuit, 17 is a frame memory, 18 is a still area interpolation correction circuit that performs interpolation and correction in a still area, 19 is a moving area interpolation circuit that performs interpolation in a moving area, and 20 is a moving area interpolation circuit that performs interpolation and correction in a moving area; The moving part detection circuit 21 that performs the detection employs the signal from the moving area interpolation circuit 19 for areas in which movement is detected based on the judgment of the moving part detection circuit 20, and for other areas. , a mixing circuit that synthesizes a video signal by employing the signal from the still area interpolation correction circuit 18; 22 is a TCI;
The decoder restores a high-definition television signal, and 23 is an output terminal for the restored high-definition television signal.

Below, a method for correcting errors in the MUSE signal reproduced by the digital VTR in this embodiment will be explained.

If an error occurs in the reproduced signal due to the influence of the tape head system or transmission system, and the error cannot be corrected by the error correction decoder 12, an error flag indicating that it is an error sample is set, and the error correction circuit 13 sets the error flag. Based on this, corrections are made using neighboring samples in the field. The modified MUSE signal is output from the output terminal 14 and is also input to the MUSE decoder 15 for restoration to the original high-definition television signal.

At the same time, the error flag is also sent to the MU along with the MUSE signal.
It is input to the SE decoder. Here, in the MUSE decoder, non-sample points are interpolated using samples from 4 fields in the static area and samples within the field in the dynamic area, but error samples are interpolated between fields in the static area. Make corrections. Error samples have already been corrected within the field by the error correction circuit 13, but for static areas, it is more accurate to correct between fields, so the results of correction between fields are output as corrected values. do.

By using the method described above, when outputting as a MUSE signal, such as dubbing, editing, or outputting to another MUSE decoder, the MU modified in the field can be used.
When the SE signal is output, restored to a high-definition television signal, and output to a monitor or the like, highly accurate correction can be performed by further performing inter-field correction in the still area. Further, when interpolating non-sample points, error samples are used, but since intra-field correction has already been performed, the image quality does not deteriorate significantly. Furthermore, in the case of high-speed playback, correlation between fields naturally disappears, but this can be dealt with by correction within the field.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described in detail, errors in a MUSE signal reproduced by a digital recording/reproducing apparatus can be corrected with high accuracy. Furthermore, the MUSE decoder has a built-in field memory for interpolation in advance, and the circuit required for inter-field correction is relatively small-scale, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a high-definition television signal error correction device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a sampling pattern of a MUSE signal in the same embodiment, and FIG. 3 is a digital FIG. 2 is a block diagram of a reproduction system of a VTR. 6.13---One error correction circuit, 1B---One static area interpolation correction circuit. Name of agent Patent attorney Shigetaka Awano One idiot Figure 2 -・−×−〇−×−・−×−○−×−・−×−〇−−X
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Claims (2)

[Claims] (1) MU made by band-compressing high-definition television signals
A high-definition television signal error correction device for correcting errors in a playback signal of a digital recording and playback device that records and plays back SE signals, comprising a first error correction means for correcting errors in the playback signal; a MUSE decoder that receives the modified MUSE signal as input and restores the original high-definition television signal; and a second error correction means that performs error correction using processing of a still area inside the MUSE decoder. , the signal corrected by the first error correcting device is adopted in the moving domain, and the signal corrected by the second error correcting device is adopted in the stationary domain to restore the high definition television signal. A high-definition television signal error correction device featuring the following features: (2) The high-definition television signal error correction apparatus according to claim 1, wherein the correction in the first and second error correction means is performed based on a flag indicating that the sample is an incorrect sample.