KR100224806B1 - Apparatus for error correction in a digital video reproducting system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to error correction of a digital image reproduction system, and more particularly, to an error correction method and apparatus for a digital image reproduction system for improving error correction capability and obtaining a high quality image by repeatedly performing error correction.

According to the present invention, error correction is performed once more for data corrected once in the same state as the amount of additional information applied to the conventional error correction apparatus, and thus the error correction rate for a certain amount of additional information is compared with that of the conventional error correction apparatus. There are advantages to improving it. In addition, in the case of reproducing at the error correction rate as in the related art, the same effect can be obtained even by reducing the amount of additional information, and there is an advantage in that the amount of data stored in the storage medium can be increased.

Description

Error Correction Method and Apparatus for Digital Video Playback System

1 is a block diagram of a conventional digital image recording and reproducing system.

Fig. 2 is a diagram for explaining the structure of the red codes and the data writing and reading directions of the deshuffling memory.

3 is a flowchart of an error correction method of a digital video reproduction system according to the present invention.

4 is a block diagram of a digital image reproducing system including an error correction apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

113: playback signal input section 114: internal decoding section

115: deshuffling memory 31: double error correction

311: outer decoding unit 312: buffer memory

313: second internal decoder 117: data recovery unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to error correction of a digital image reproduction system, and more particularly, to an error correction method and apparatus for a digital image reproduction system for improving error correction capability and obtaining a high quality image by repeatedly performing error correction.

A device for converting a video or audio data into a digital signal and then storing or transmitting the recording data is limited by the capacity of the storage medium since the amount of digital data is much higher than that of analog data. To solve this problem, a method of increasing the recording density of a storage medium and a method of reducing the amount of data by compressing digital data are used. However, when the recording density is increased or the data is compressed, the error becomes very sensitive accordingly.

In general, digital video equipment such as a digital video cassette recorder (DVCR) or a compact disk system (Compact Disk System) is an error correction code to prevent deterioration of image quality due to errors occurring during recording and playback. Error Correcting Coding, Decoding, and Error Concealment are used.

Most error correction systems adopted in magnetic tapes and optical discs are product code using Reed-Solomon code or cross interleaved Reed-Solomon code, a kind of red code. CIRC). The Reed-Solomon code is an error correcting code widely applied to correct an error of a computer storage device and a digital communication system by correcting a random error pattern as well as a burst error.

Here, the proper code or CIRC code is double encoded and decoded to perform error correction to maximize error correction capability. That is, inner encoding and outer encoding are performed when data is recorded, and inner decoding and outer decoding are performed when data is reproduced.

However, the error correction code has a very good ability to correct random errors, but it is practically impossible to correct a collection error. Therefore, it is necessary to convert the continuous error having a continuous form into a form such as a random error. Shuffling is to perform such a function, and means to shuffle data included in a predetermined range in the same manner as shuffle cards when recording data onto a recording medium. At this time, data that has been shuffled and recorded should be deshuffled at the time of reproduction.

As described above, the error correction apparatus undergoes only one error correction decoding process, i.e., an internal decoding and an external decoding process, during playback. Therefore, when error correction is not performed in one error correction decoding process, an error correction method for restoring the compressed image information after restoring the compressed image information is performed using the error correction method for restoring the compressed image information. To prevent deterioration of image quality to some extent.

However, if the error is not corrected, the image signal of the previous frame is restored as it is in the error correction process. If there is a portion in which the error is not corrected in the image signal of the previous frame, the image containing the error continues to appear. There was a problem in that the image quality is deteriorated and the original image quality is not obtained.

Accordingly, an object of the present invention is to provide an error correction method capable of increasing error correction capability in a digital video reproduction system for correcting an error included in a playback signal using an error correction code.

Another object of the present invention is to provide an error correction apparatus that can perform an error correction process consisting of internal decoding and external decoding in a digital video reproduction system for correcting an error included in a playback signal using an error correction code. There is.

In order to achieve the above object, an error correction method of a digital image reproducing system according to the present invention comprises an appropriate code including vertical sub information added by internal encoding as horizontal error information added as an error correction code of image data and horizontal sub information added by external encoding. A digital video reproducing system for reproducing an error of a playback signal according to the error correcting code and reproducing the original video data with respect to a reproduced signal comprising: a method for identifying an error of the playback signal using the vertical additional information. A first outer decoding step of correcting an error of a playback signal that has passed the first inner decoding step by using the horizontal additional information, and a rearranged playback signal by rearranging the playback signals that have passed the first outer decoding step. A second internal decoding step of converting the data into a data order and correcting an error of a reproduction signal using the vertical additional information; And a second outer decoding step of rearranging the playback signals that have undergone the inner decoding step and converting them into a data order that can be decoded and correcting errors in the playback signals using the horizontal additional information.

The error correcting apparatus of the digital image reproducing system according to the present invention for achieving the above another object is an error code consisting of vertical sub information added by internal encoding and horizontal sub information added by external encoding as an error correcting code of image data. A digital video reproducing system for reproducing an original video data by correcting an error of a playback signal according to the error correcting code with respect to a playback signal comprising a, comprising: correcting an error of a playback signal using the vertical additional information. A first internal decoder to correct an error of the first internally decoded reproduction signal using the horizontal additional information, and correct the error using the vertical additional information and the horizontal additional information again. It is characterized by including the double error government.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a conventional digital video recording and reproducing system. FIG. 1a is a block diagram of a digital video recording system and FIG. 1b is a block diagram of a digital video recording system.

Conventional digital image recording systems include an analog-to-digital converter 101, a data compressor 102, an outer encoder 103, a shuffling memory 104 ), An inner encoder 105, and a recording output unit 106.

The analog-digital converter 101 converts the incoming input image signal into a digital image signal, and the data compressor 102 compresses the data output from the analog-digital converter by using a data compression technique.

The external encoder 103 adds the horizontal sub information to the compressed input data with respect to the vertical data, and the shuffling memory 104 shuffles the image data to which the horizontal sub information is added from the external encoder 103. After ringing, the vertical encoder 105 adds vertical additional information to the data in the horizontal direction.

The recording output unit 106 is composed of a modulator for modulating the output of the internal encoder 105 and a recording amplifier for amplifying the output of the modulator after adding index information ID for distinguishing between reproduction data during reproduction. Data is recorded on the recording medium 108.

The conventional digital image reproducing system includes a reproduction signal input unit 113, an inner decoder 114, a deshuffling memory 115, an outer decoder 116, and data restoration. Section 117, digital-to-analog converter 118.

The reproduction signal input unit 113 includes a reproduction amplifier for amplifying the signal reproduced from the recording medium 111, a demodulator for demodulating the modulated data, and the like. Data, audio and video information reproduced from the recording medium 111 such as a magnetic tape or an optical disc are amplified by a reproduction amplifier, demodulated by a demodulator, and then output to the internal decoding unit 114 through a synchronous detector.

The internal decoding unit 114 corrects the random error by using the horizontal additional vertical information of the output data of the reproduction signal input unit 113, and does not qualitatively correct an error exceeding the correction range and fails to correct the entire code. An error flag, which is a signal indicating that error correction cannot be performed, is added to the output.

The deshuffling memory 115 records the data output from the internal decoder 114, rearranges the mixed data in the data order before shuffling the data, and reads the data in an outer codeword format so as to read the outer coder. 116).

The outer decoding unit 116 corrects the error for the outer code block by using the horizontal sub information according to the error flag, and outputs the output data of the deshuffling memory 115. The outer decoding unit 116 performs erasure correction when an error flag is added to the input data, and performs general error correction when the error flag is not added.

The data restoring unit 117 is an image restoring unit for restoring the data outputted from the outer decoding unit 116, and an error carrying out of the error correction capability range is used for restoring the compressed image information before using the image information of all frames. Error correction and error correction outputs are detected, and the motion information, that is, the difference between the video information between the current frame and the previous frame is detected, and the moving picture is output as it is. In the case of an image having a certain degree of motion, a noise canceling unit for outputting an image signal by mixing the image signal of the current frame and the image signal of the immediately preceding frame, and the analog-to-analog converter 118 Is converted to.

FIG. 2 shows the structure of the red code and the data writing / reading direction of the deshuffling memory. FIG. 2a shows the structure of the red code with additional information appended. FIG. 2b shows the data recording of the deshuffling memory. 2C is a diagram showing a data reading direction of the deshuffling memory.

The proper code is composed of the horizontal additional information 31 added by the external coder and the vertical additional information 32 added by the internal coder to the data 30. The deshuffling memory sequentially writes the output data of the inner decoding unit in the horizontal direction for each inner arc as shown in FIG. 2B. Then, the recorded data is sequentially read in the vertical direction as shown in FIG. 2C, and output to the outer decoding unit 70. FIG.

3 is a flowchart showing an error correction method of a digital image reproducing system according to the present invention. As an error correcting code of video data, it is possible to perform internal decoding on a reproduction signal including an appropriate code consisting of vertical additional information and horizontal additional information. The error correction process consisting of the external decoding is performed twice.

The reproduction signal is subjected to the first internal decoding 31 for correcting the error of the reproduction signal using the vertical additional information, and then shuffled the shuffled data during recording.

A first outer decoding step 32 is then performed to correct the error of the first inner decoded playback signal using the horizontal sub information.

The reproduction signal that has undergone the first outer decoding step can be internally decoded by rearranging the data in the buffer with the address first increasing in the vertical direction, and then reading the data in the buffer with the address first increasing in the horizontal direction. A second internal decoding step 33 is performed in which data is converted into the data order to correct an error of the reproduction signal using the vertical additional information.

The reproduction signal that has undergone the second internal decoding step can be externally decoded by rearranging the data in the buffer with the address first increasing in the horizontal direction and then reading the data in the buffer with the first address increasing in the vertical direction. A second outer decoding step 34 is performed in which data errors are converted into data order to correct an error of a reproduction signal using the horizontal additional information.

4 is a block diagram of a digital image reproducing system including an error correction apparatus according to the present invention. In order to double the error correction process, a double error correction is composed of an outer decoding unit 411, a buffer memory 412, a second inner decoding unit 413 and an address control unit 414 together with the inner decoding unit 114. It includes a government 31, the function of decoding the outer decoding unit 411 and the second inner decoding unit 413 is the same as the functions of the conventional outer decoding unit and the inner decoding unit, respectively.

The functions of the reproduction signal input unit 113, the internal decoding unit 114, and the deshuffling memory 115 are the same as those shown in FIG. 1, and the internal decoding unit 114 performs the first internal decoding and deshuffling. The memory 115 rearranges the data prior to shuffling, reads them in an external codeword format, and outputs them to the external decoding unit 411.

The outer decoding unit 411 firstly decodes the deshuffled data 401 by correcting an error with respect to the outer code block using the horizontal additional information. The first outer decoded data 402 is written to the buffer memory 412, and the address control section 414 writes the data to an address that first increases in the vertical direction.

The address controller 414 reads the data in the buffer memory 412 at an address that first increases in the horizontal direction, outputs the data to the data array 403 for internal decoding, and inputs the data to the second internal decoding unit 413.

The second internal decoding unit 413 corrects the error using the vertical additional information to read the data 403, and then performs second internal decoding. The second internally decoded data 404 is written to the buffer memory 413 again, and the address controller 414 writes the data to the buffer memory 412 at an address that first increases in the horizontal direction.

The address controller 414 reads the data in the buffer memory 412 at an address that first increases in the vertical direction, outputs the data to the data array 405 for external decoding, and inputs the data to the external decoding unit 411 again.

The outer decoding unit 411 second-decodes the read data 405 by correcting an error using the horizontal additional information. The error corrected data by the second internal decoding and the second external decoding is output to the data restoring unit 117.

The external decryption unit 411 and the second internal decryption unit 413 of the double error correction unit 41 are composed of one component having both functions of external decryption and internal decryption, and according to a control signal, 2 can be operated as an internal decoding unit. The control signal is a signal for selecting the internal decoding and the external decoding according to the data writing and output directions of the buffer memory 412 which are changed by the error correction process in the address controller 414 or the system controller.

As described above, according to the present invention, the error correction data is once again corrected in the same state as the amount of additional information applied to the conventional error correction apparatus, so that the amount of additional information is fixed compared to the conventional error correction apparatus. This has the advantage of improving the error correction rate. In addition, in the case of reproducing at the error correction rate as in the related art, the same effect can be obtained even by reducing the amount of additional information, and there is an advantage in that the amount of data stored in the storage medium can be increased.

Claims (5)

For a reproduction signal including an appropriate code consisting of information of a vertical portion added internally as an error correcting code of video data and horizontally added information added externally, the error of the reproduction signal is corrected according to the error correction code. A digital video reproducing system for reproducing video data of an image, comprising: a first internal decoder for correcting an error of a reproduction signal using the vertical sub information, and a first internal decoded reproduction signal using the horizontal sub information. A double error correction unit for correcting an error and correcting the error using the vertical additional information and the horizontal additional information again, wherein the double error correction unit is a storage means for recording or reading data. For recording and reading data to and from the storage means in order of data to be decoded or internally decoded or decoded. A second decoding unit for correcting an error of a reproduction signal by using the horizontal sub information and outputting the correction signal to the storage unit, and outputting the error to the storage unit by correcting an error of the reproduction signal using the vertical sub information. And an internal decoding unit, which records the output data of the external decoding unit in the storage unit in a data order for internal decoding by the address control unit, and then reads the data into the second internal decoding unit to read the data into the second internal decoding unit. (2) writes the output data, which is internally decoded, and the second internally decoded output data by the second internal decoding unit, in the data order for external decoding by the address control means, is read into the external decoding unit, and then read by the external decoding unit. And a second external decoding unit outputs the decoding unit to output the error correction apparatus of the digital image reproducing system. 2. The apparatus according to claim 1, wherein the means for recording and reading data in a data order for internal decoding of said address control means writes data to said storage means at an address that first increases in the horizontal direction, and increases first in the vertical direction. And an error correction apparatus for reading the data of the storage means at an address. 2. The apparatus according to claim 1, wherein the means for recording and reading data in data order for external decoding of the address control means writes data to the storage means at an address that first increases in the vertical direction, and increases first in the horizontal direction. And an error correction apparatus for reading the data of the storage means at an address. The apparatus of claim 1, wherein the outer decoding unit and the second inner decoding unit are configured as one device having both functions of outer decoding and inner decoding, and operate as an outer decoding unit or a second inner decoding unit according to a control signal. An error correcting device for a digital video playback system. 5. The error correcting apparatus according to claim 4, wherein said control signal is a signal generated by said address control means in accordance with a data recording and output direction of said storage means.