Image analysis – Image compression or coding – Adaptive coding
Reexamination Certificate
1999-11-02
2003-04-22
Johns, Andrew W. (Department: 2621)
Image analysis
Image compression or coding
Adaptive coding
C382S232000, C341S063000, C714S795000
Reexamination Certificate
active
06553145
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a video data transceiving device, and a transceiving method thereof, and more particularly, to a video data transceiving device for transceiving video data, which performs discriminative error protection according to the significance of the video data, and a method thereof.
2. Description of the Related Art
Compressed video data is sensitive to errors due to the characteristics of compression algorithms. Therefore, research has been done on methods for coping with errors likely to be generated during the transmission of video information via a communications channel.
FIG. 1
is a block diagram illustrating the structure of a conventional video data transceiving device
1
. Referring to
FIG. 1
, the device
1
includes a transmit stage
10
and a receive stage
12
. The transmit stage
10
includes a video data supply portion
100
for supplying video data, a video data encoder
102
for compressing received video data, a forward error correction (FEC) coder
104
for adding various error correction codes including redundancy information to compressed video data provision against noise generated on a communications channel, and an interleaver
106
for interleaving a bit stream generated and output from the FEC coder
104
. The receive stage
12
includes a deinterleaver
120
for recovering the interleaved bit stream, an FEC decoder
122
for decoding a signal (not shown) which is encoded by the FEC coder
104
and has error correction codes added thereto, and outputting compressed video data, a video data decoder
124
for recovering the compressed video data, and a video sync
126
.
In the operation of the system
1
, a video data signal output from the video data supply portion
100
is input to the video data encoder
102
and compressed. Compressed video data is input to the FEC encoder
104
, and various error correction codes including redundancy information are added to the compressed video data. The interleaver
106
performs an interleaving operation of rearranging a signal output from the FEC encoder
104
in a predetermined sequence to prevent generation of burst errors liable to be generated by fading under a wireless environment, and transmits the resultant signal to a communications channel. The deinterleaver
120
performs a deinterleaving operation of receiving the signal transmitted via the communications channel and rearranging it into the original sequence. The deinterleaved signal is decoded by the FEC decoder
122
. The video data decoder
124
receives the decoded signal and decompresses the decoded signal, thereby reducing video data. In this way, the conventional video data transmitting and receiving device
1
copes with noise that can be added to the communications channel.
Typically, in the device
1
, it is assumed that the bits of a bit stream output from the video data encoder
102
all have the same significance. However, the compressed video data has different levels of significance. When video data of high significance is damaged by an error, degradation of the quality of an image becomes relatively serious. This problem is solved by adding a large amount of redundancy information to the video data to facilitate the restoration of the damaged video data. In this case, overhead information increases, causing a problem in that the channel rate is increased.
FIG. 2
is a block diagram of a conventional video data transceiving device for fixing the above-described problem. Referring to
FIG. 2
, the conventional video data transceiving device
2
includes a rate compatible punctured convolution (RCPC) encoder
202
for performing RCPC.
In the operation of the device
2
, first, a video data encoder
200
divides a syntax element into several grades according to the significance of the syntax element, and transmits source significance information (SSI) including the information of the grades to the RCPC encoder
202
. The RCPC encoder
202
extracts puncturing rule information and transmits coding information including the above information to a viterbi decoder
208
. Accordingly, the RCPC encoder
202
performs channel coding on each grade by applying an error correction coding method, and the viterbi decoder
208
decodes a channel on the basis of the puncturing rule information, thereby improving the error correction capability.
However, in the device
2
, the syntax elements of compressed video data have different SSI, and variable length coding is performed according to the SSI, so that each bit stream of video data has a different length according to the significance of the video data. For a video data bit stream prior to convolution coding, its significance is frequently changed, and the coding rule corresponding to the significance is thus also frequently changed during RCPC coding. In particular, when the coding ratio is changed with respect to small sections, there is a disadvantage in that the error correction performance of the device
2
is liable to be degraded due to the characteristics of the RCPC, as compared to when a typical convolution coding method is used.
Meanwhile, a general video compression algorithm uses a variable length, coding method, uses a prediction coding technique referring to a previous frame or a previous macro block, records coding information using administrative information, and performs decoding based on the administrative information. However, when error is generated upon coding a spatially macro block, this compression algorithm is highly likely to affect the decoding of the next and successive code word. Also, when an error is generated in the coding word of a previous frame or a macro block, the compression algorithm is highly likely to affect the decoding of the next frame or macro block. Further, when an error is generated in the administrative information, the compression algorithm may affect an entire video sequence or an entire frame. Further still, in a channel coding process, the amount of data is increased by adding various error correction codes to the compressed video data.
Consequently, in a conventional video data transceiving device, it does not control an increase of data upon channel coding according to the significance of compressed video data, causing a disadvantage in that it is difficult to use a limited channel capacity effectively.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide a video data transmitting device which performs discriminative error protectional channel coding according to the significance of video data.
It is another objective of the present invention to provide a video data receiving device for receiving and restoring video data which is channel-coded by the transmitting device.
It is still another objective of the present invention to provide a video data transceiving device which performs discriminative error protectional channel coding and transmits video data by discriminative error protection of the video data according to the significance of the video data, and receiving and restoring the channel coded video data.
It is yet another objective of the present invention to provide a video data coding method performed by the transmitting device.
It is still yet another objective of the present invention to provide a video data decoding method performed by the receiving device.
Accordingly, to achieve the first objective, there is provided a video data transmitting device comprising: a compression portion for discriminating the significance of the video data, generating region information classified by regions, compressing the video data by regions according to the region information, and outputting compressed video data; and a coding portion for coding the compressed video data by regions according to a predetermined coding rule corresponding to the significance included in the region information using the RCPC coding method, and inserting a predetermined marker.
It is preferable that the compression portion comprises:
Kang Sang-ug
Yoo Kook-yeol
Dang Duy M.
Johns Andrew W.
Samsung Electronics Co,. Ltd.
Sughrue & Mion, PLLC
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