The Experts below are selected from a list of 45 Experts worldwide ranked by ideXlab platform
Michelle Effros - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Separable Karhunen Loeve Transforms for the weighted universal Transform coding algorithm
1999 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999Co-Authors: Hanying Feng, Michelle EffrosAbstract:The weighted universal Transform Code (WUTC) is a two-stage Transform Code that replaces JPEG's single, non-optimal Transform Code with a jointly designed collection of Transform Codes to achieve good performance across a broader class of possible sources. Unfortunately, the performance gains of WUTC are achieved at the expense of significant increases in computational complexity and larger Codes. We here present a faster, more space-efficient WUTC algorithm. The new algorithm uses separable coding instead of direct KLT. While separable coding gives performance comparable to that of WUTC, it uses only 1/8 of the floating-point multiplications and 1/32 of storage of direct KLT. Experimental results included in this work compare the performance of new separable WUTC with both the WUTC and other fast variations of that algorithm.
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Data Compression Conference - Fast weighted universal Transform coding: toward optimal, low complexity bases for image compression
Proceedings DCC '97. Data Compression Conference, 1Co-Authors: Michelle EffrosAbstract:Effros and Chou (see Proceedings of the IEEE International Conference on Image Processing, Washington, DC, 1995) introduce a two-stage universal Transform Code called the weighted universal Transform Code (WUTC). By replacing JPEG's single, non-optimal Transform Code with a collection of optimal Transform Codes, the WUTC achieves significant performance gains over JPEG. The computational and storage costs of that performance gain are effectively the computation and storage required to operate and store a collection of Transform Codes rather than a single Transform Code. We consider two complexity- and storage-constrained variations of the WUTC. The complexity and storage of the algorithm are controlled by constraining the order of the bases. In the first algorithm, called the fast WUTC (FWUTC), complexity is controlled by controlling the maximum order of each Transform. On a sequence of combined text and gray-scale images, the FWUTC achieves performance comparable to the WUTC. In the second algorithm, called the jointly optimized fast WUTC (JWUTC), the complexity is controlled by controlling the average order of the Transforms. On the same data set and for the same complexity, the performance of the JWUTC always exceeds the performance of the FWUTC. The JWUTC and FWUTC algorithm are interesting both for their complexity and storage savings in data compression and for the insights that they lend into the choice of appropriate fixed- and variable-order bases for image representation.
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DCC - Suboptimality of the Karhunen-Loeve Transform for Transform coding
Data Compression Conference 2003. Proceedings. DCC 2003, 1Co-Authors: Michelle Effros, Hanying Feng, Kenneth ZegerAbstract:The performance of the KLT for Transform coding applications was examined. The KLT has long been viewed as the best available block Transform for Transform coding. The fixed-rate and variable-rate Transform Codes were also presented. The fixed-rate approach uses an optimal fixed-rate scalar quantizer to describe the Transform coefficients; the variable-rate approach uses a uniform scalar quantizer followed by an optimal entropy Code. Earlier work shows that for the variable-rate case, there exist sources on which the KLT is not unique and the optimal Transform Code matched to a "worst" KLT yields performance as much as 1.5 dB worse than the optimal Transform Code matched to a "best" KLT. The results were strengthened to show that in both the fixed-rate and the variable-rate coding frameworks, there exist sources for which the performance penalty for using a "worst" KLT can be made arbitrarily large. Further demonstrations in both frameworks show that there exist sources for which even a best KLT gives suboptimal performance. Finally, the results show that even for vector sources where the KLT yields independent coefficients, the KLT can be suboptimal for fixed-rate coding.
Hanying Feng - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Separable Karhunen Loeve Transforms for the weighted universal Transform coding algorithm
1999 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999Co-Authors: Hanying Feng, Michelle EffrosAbstract:The weighted universal Transform Code (WUTC) is a two-stage Transform Code that replaces JPEG's single, non-optimal Transform Code with a jointly designed collection of Transform Codes to achieve good performance across a broader class of possible sources. Unfortunately, the performance gains of WUTC are achieved at the expense of significant increases in computational complexity and larger Codes. We here present a faster, more space-efficient WUTC algorithm. The new algorithm uses separable coding instead of direct KLT. While separable coding gives performance comparable to that of WUTC, it uses only 1/8 of the floating-point multiplications and 1/32 of storage of direct KLT. Experimental results included in this work compare the performance of new separable WUTC with both the WUTC and other fast variations of that algorithm.
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DCC - Suboptimality of the Karhunen-Loeve Transform for Transform coding
Data Compression Conference 2003. Proceedings. DCC 2003, 1Co-Authors: Michelle Effros, Hanying Feng, Kenneth ZegerAbstract:The performance of the KLT for Transform coding applications was examined. The KLT has long been viewed as the best available block Transform for Transform coding. The fixed-rate and variable-rate Transform Codes were also presented. The fixed-rate approach uses an optimal fixed-rate scalar quantizer to describe the Transform coefficients; the variable-rate approach uses a uniform scalar quantizer followed by an optimal entropy Code. Earlier work shows that for the variable-rate case, there exist sources on which the KLT is not unique and the optimal Transform Code matched to a "worst" KLT yields performance as much as 1.5 dB worse than the optimal Transform Code matched to a "best" KLT. The results were strengthened to show that in both the fixed-rate and the variable-rate coding frameworks, there exist sources for which the performance penalty for using a "worst" KLT can be made arbitrarily large. Further demonstrations in both frameworks show that there exist sources for which even a best KLT gives suboptimal performance. Finally, the results show that even for vector sources where the KLT yields independent coefficients, the KLT can be suboptimal for fixed-rate coding.
Jean-marie Gorce - One of the best experts on this subject based on the ideXlab platform.
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Toward Increasing Packet Diversity for Relaying LT Fountain Codes in Wireless Sensor Networks
IEEE Communications Letters, 2011Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic and lower complexity Luby Transform Code in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
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Towards increasing packet diversity for relaying LT Fountain Codes in Wireless Sensor Networks
2010Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic Luby Transform Code in order to maintain high transmission performance with low decoding computational complexity in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
Anya Apavatjrut - One of the best experts on this subject based on the ideXlab platform.
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Toward Increasing Packet Diversity for Relaying LT Fountain Codes in Wireless Sensor Networks
IEEE Communications Letters, 2011Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic and lower complexity Luby Transform Code in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
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Towards increasing packet diversity for relaying LT Fountain Codes in Wireless Sensor Networks
2010Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic Luby Transform Code in order to maintain high transmission performance with low decoding computational complexity in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
Cristina Comaniciu - One of the best experts on this subject based on the ideXlab platform.
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Toward Increasing Packet Diversity for Relaying LT Fountain Codes in Wireless Sensor Networks
IEEE Communications Letters, 2011Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic and lower complexity Luby Transform Code in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
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Towards increasing packet diversity for relaying LT Fountain Codes in Wireless Sensor Networks
2010Co-Authors: Anya Apavatjrut, Claire Goursaud, Cristina Comaniciu, Katia Jaffrès-runser, Jean-marie GorceAbstract:Diversity is a powerful means to increase the transmission performance of wireless communications. For the case of fountain Codes relaying, it has been shown previously that introducing diversity is also beneficial since it counteracts transmission losses on the channel. Instead of simply hop-by-hop forwarding information, each sensor node diversifies the information flow using XOR combinations of stored packets. This approach has been shown to be efficient for random linear fountain Codes. However, random linear Codes exhibit high decoding complexity. In this paper, we propose diversity increased relaying strategies for the more realistic Luby Transform Code in order to maintain high transmission performance with low decoding computational complexity in a linear network. Results are provided herein for a linear network assuming uniform imperfect channel states.
