To overcome some drawbacks of Viterbi algorithm （VA）, such as exponential growing complexity of decoding, and its poor performance under bad channel conditions, some available known information must be used as cons...To overcome some drawbacks of Viterbi algorithm （VA）, such as exponential growing complexity of decoding, and its poor performance under bad channel conditions, some available known information must be used as constrained condition and apriori knowledge for decoding. A new constrained VA is proposed by adding con- straint bits directly for conventional codec. Compared with the conventional VA, under the bad channel condi- tion, the proposed scheme can improve the peak signal to noise ratio （PSNR） of the decoding image 2--10 dB by changing the number of constrained bits. Experimental results show that it is an efficient error-controlling way for the transmission of set partitioning in hierarchical trees （SPIHT） coded image.展开更多
The constrained Viterbi algorithm （C-VA） makes use of some prior reliable information to reduce complexity and improve performance of Viterbi algorithm （VA）. However it can only be used in the concatenate code sch...The constrained Viterbi algorithm （C-VA） makes use of some prior reliable information to reduce complexity and improve performance of Viterbi algorithm （VA）. However it can only be used in the concatenate code scheme because the detection result of cyclic redundancy check code （CRC） is exploited to provide reliable information. In this paper, a different way is proposed to provide reliable information for C-VA, which is possible to be used in simple codec. Known bits were added to the set partitioning in hierarchical trees （SPIHT） coded image sequence periodically and directly. They were thought to be reliable information for C-VA in the decoder. Experimental results show that the proposed scheme can obtain much better error resilient ability compared with conventional VA under the extremely inferior channel condition if the best desired quality of reconstructed images can be sacrificed.展开更多
文摘To overcome some drawbacks of Viterbi algorithm （VA）, such as exponential growing complexity of decoding, and its poor performance under bad channel conditions, some available known information must be used as constrained condition and apriori knowledge for decoding. A new constrained VA is proposed by adding con- straint bits directly for conventional codec. Compared with the conventional VA, under the bad channel condi- tion, the proposed scheme can improve the peak signal to noise ratio （PSNR） of the decoding image 2--10 dB by changing the number of constrained bits. Experimental results show that it is an efficient error-controlling way for the transmission of set partitioning in hierarchical trees （SPIHT） coded image.
基金Project supported by the National Natural Science Foundation of China (Grant No.60372070)
文摘The constrained Viterbi algorithm （C-VA） makes use of some prior reliable information to reduce complexity and improve performance of Viterbi algorithm （VA）. However it can only be used in the concatenate code scheme because the detection result of cyclic redundancy check code （CRC） is exploited to provide reliable information. In this paper, a different way is proposed to provide reliable information for C-VA, which is possible to be used in simple codec. Known bits were added to the set partitioning in hierarchical trees （SPIHT） coded image sequence periodically and directly. They were thought to be reliable information for C-VA in the decoder. Experimental results show that the proposed scheme can obtain much better error resilient ability compared with conventional VA under the extremely inferior channel condition if the best desired quality of reconstructed images can be sacrificed.
