JPH0319486A - Digital data recorder - Google Patents

Abstract

PURPOSE:To improve visual picture quality by recording an identification signal for propriety of correction to a recording and reproducing section at data recording and applying switching control to the connection to a correction circuit in response to the identification signal at data reproduction. CONSTITUTION:A coding circuit 2 adds a bit error correction code to a data, inputs the result to a conversion circuit 3, where the data is converted into a data suitable for magnetic recording and recorded on a magnetic tape by a recording and reproducing section 4. In this case, an identification signal representing whether the format is a standard television format or a high definition television format is inputted to a control circuit 5 and the signal is recorded on a magnetic tape with the recording and reproducing section 4 together with the picture data. At reproduction when the identification signal represents the standard television format, a switch of a changeover device 8 is turned to the position of (b), the correction circuit 9 corrects the signal and in the case of the high definition television format, the switch of the changeover device 8 is turned to the position of (a) to bypass the correction circuit. Thus, the reproduction picture quality is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a digital data recorder, such as a digital video tape recorder (hereinafter abbreviated as "digital VTRJ"), which digitizes and records and reproduces video signals. In particular, when recording a high-definition image with more scanning lines and a larger image matrix size in addition to standard matrix size images, data that cannot be error-corrected during playback may be recorded in the previous image. The present invention relates to a digital data recorder that improves image quality by effectively using a correction mode in which data is replaced with the same address data.

[Conventional technology]

recent years. With the advancement of digital ICs (integrated circuits), the development of digital VTRs that enable high-quality recording and playback by digitizing television video signals is progressing (Television Society Journal VoQ.39, &4.1985, p3
12-p315, ``Digital VTRJ'').Such a digital VTR digitizes the video signal input from another image device using an A/D converter, and transfers this digital data to a magnetic tape, etc. in the recording/reproducing section. The digital data is recorded on or reproduced from a magnetic recording medium, and the digital data read out from the recording/reproducing section is converted into a video signal by a D/A converter and output. Code error (hereinafter referred to as "error J")
is corrected using an error correction code added before recording. For errors that exceed the correction ability, they are replaced with data at the same position in the previous image (hereinafter referred to as "Modification II").This improves image quality.On the other hand, some recent medical devices In order to improve the diagnostic ability of medical images, a system has been developed that captures and displays high-definition images with the number of scanning lines increased to 1050, twice that of the standard television system. , the digital VT
Since images that can be recorded and reproduced in R are limited to standard television format, in order to record the above-mentioned high-definition medical images, it is necessary to divide and record the high-definition image data. If an image was simply divided into four parts and recorded, if any corrections were made during playback, the data would be replaced with completely different data, so it was necessary to remove the corrections. However, when playing back standard television format images.
There was a problem where errors were displayed as they were because there was no correction mode. (Problem that J@Ming is trying to solve) The above conventional technology does not take into account the use of modification modes suitable for standard television system image signals and high-definition image television signals, and when in semi-TV mode, However, there was a problem in which errors were noticeable.The purpose of the present invention is to improve the playback image quality by using the correction mode only in the standard TV mode and not in the high-definition TV mode. Means for Solving] When recording images on a digital VTR, an identification signal between a standard television system image signal and a high-definition image television signal is recorded together with the image data, and the identification signal is used when playing back. Use to switch the correction mode. In other words,
Use retouching mode when using a standard television format image signal, and turn off retouching mode when using a high-definition image television signal. [Operation] When recording an image, an identification signal is recorded in a part of the image area or audio track to indicate whether it is a standard TV format or a high-definition TV format. During playback, the signal is read out and the correction mode is turned on or off depending on the format of the recorded image. [Example] An example of the present invention will be described below with reference to FIG.

Figure 1 shows a system block diagram of a digital VTR. The video input is digitized by A/D conversion m1, and if it is a digital input, it is input to the encoding circuit 2 as is. The encoding circuit 2 adds an error correction code to the data to correct bit errors caused by scratches on the tape or poor contact with the head during playback, and inputs the data to the conversion circuit 3. A conversion circuit 3 converts the data into a data structure suitable for magnetic recording, and then a recording/reproducing section 4 records the data on a magnetic tape. At this time, an identification signal indicating whether it is a standard television format or a high-definition television format is input to the control circuit 5, and the signal is recorded on a magnetic tape by the recording/reproducing section 4 together with the image data. Here, as an example, as shown in FIG. 2, FM modulation is performed and recorded on the audio track 12 of the magnetic tape 11. Next, during reproduction, the data read from the recording and reproducing section 4 is inversely converted from a format suitable for magnetic recording to the original format by an inverse conversion circuit 6 and inputted to a correction circuit 7. The correction circuit 7 performs error correction using the error correction code added by the code circuit 2 during recording, and then inputs the data to the switch 8. The identification signal of the TV format recorded on the audio track 12 of the magnetic tape 11 is read at the same time as the reproduction, and if it is the IJl semi-TV format, the switch of the selector 8 is connected to the b side, and correction is performed by the correction circuit 9. In the case of high-definition television format, connect the switch of switch 8 to the a side and bypass the correction circuit. Thereafter, both are digitally output and, at the same time, video is output by the D/A converter 10. In this embodiment, the television format identification signal is recorded on the audio track l2 of the magnetic tape 11, but it may also be recorded on a part of the image data area. Although bypassed, it is also possible to record in standard television format without any retouching. That is, instead of recording whether the format is a standard television format or a high-definition television format, it is sufficient to record whether or not correction is to be performed during playback. Even in standard television formats, if the same image is recorded three times and error correction is performed by majority voting between the bits of each image, it will be more reliable to bypass the correction mode. [Effects of the Invention] According to the present invention, the retouching process can be stopped only in special cases such as high-definition images or majority processing in standard TV formats, and can be performed at other times, resulting in improved image quality. Visual improvements can be made.

[Brief explanation of drawings]

FIG. 1 is a system block diagram showing an embodiment of the present invention;
Figure 2 shows the recording format of magnetic tape. DESCRIPTION OF SYMBOLS 1... A/D converter, 2... Code circuit, 3... Conversion circuit, 4... Recording/reproducing part, 5... Control circuit, 6...
... Distribution conversion circuit, 7... Correction circuit, 8... Switch, 9... Correction circuit, 10... D/A converter, 11.
...Magnetic tape, 12...Audio track.

Claims (1)

[Claims] 1. A/D converter that digitizes the video signal, a code circuit that adds an error correction code, a recording/reproducing unit that performs magnetic recording, a correction circuit that performs error correction, and a modification that replaces code errors that cannot be corrected with front image data. In a digital data recorder comprising a circuit and a D/A converter for converting into a video signal, an identification signal indicating whether or not modification is necessary is recorded in the recording/reproducing section when recording data, and the modification is performed according to the identification signal during data reproduction. A digital data recorder characterized by comprising a control means for switching and controlling connections to a circuit.