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permutation coding for Vertex-Blend Attribute Compression

PROCEEDINGS OF THE ACM ON COMPUTER GRAPHICS AND INTERACTIVE TECHNIQUES 2022年第1期5卷 1–16页

作者： Peters, Christoph Kuth, Bastian Meyer, Quirin Karlsruhe Inst Technol Fasanengarten 5 D-76131 Karlsruhe Germany Coburg Univ Appl Sci & Arts Friedrich Streib Str 2 D-96450 Coburg Germany

Compression of vertex attributes is crucial to keep bandwidth requirements in real-time rendering low. We present a method that encodes any given number of blend attributes for skinning at a fixed bit rate while keeping the worst-case error small. Our method exploits that the blend weights are sorted. With this knowledge, no information is lost when the weights get shuffled. Our permutation coding thus encodes additional data, e.g. about bone indices, into the order of the weights. We also transform the weights linearly to ensure full coverage of the representable domain. Through a thorough error analysis, we arrive at a nearly optimal quantization scheme. Our method is fast enough to decode blend attributes in a vertex shader and also to encode them at runtime, e.g. in a compute shader. Our open source implementation supports up to 13 weights in up to 64 bits.

关键词： skinning linear vertex blend animation vertex buffer compression vertex blend attribute compression permutation coding bone weights bone indices simplex tetrahedron

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permutation coding with Differential Quinary Phase Shift Keying for Power Line Communication

Permutation Coding with Differential Quinary Phase Shift Key...

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5th IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe)

作者： Ogunyanda, K. Familua, A. D. Swart, T. G. Ferreira, H. C. Cheng, L. Univ Johannesburg Dept Elect & Elect Engn Sci ZA-2006 Auckland Pk South Africa Univ Witwatersrand Sch Elect & Informat Engn ZA-2050 Johannesburg South Africa

ISBN: (纸本)9781479977208

permutation coding (PC) has been known to be effective in combating power line channel impairments, when used in concatenation with other channel coding schemes like convolutional or Reed Solomon (RS) codes, using FSK, PSK or DPSK as the modulator. We hereby report the development of a modified DPSK modulator, called differential quinary PSK (DQuiPSK), with only 5 constellations, to improve the performance of permutation coded DPSK-OFDM modulation for power line communication (PLC) purposes. This combination is, therefore, termed an RS-PC-DQuiPSK-OFDM scheme, with RS being used as an outer code. To implement this over power line, universal software radio peripherals, which are software defined radio hardware, originally designed for radio communications, were used together with narrowband coupling circuits, to interface with the power line. Simulations and practical implementation results show the strength and competitive performance of our scheme over the conventional convolutional coded D8PSK-OFDM scheme specified in the narrowband PLC standard.

关键词： Channel coding OFDM modulation permutation coding PLC G3 Power Line Communication PRIME Quinary Phase Shift Keying Software Defined Radio

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THE ROLE OF permutation coding IN MINIMUM-DISTORTION PERFECT COUNTERFORENSICS

THE ROLE OF PERMUTATION CODING IN MINIMUM-DISTORTION PERFECT...

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Balado, Felix Univ Coll Dublin Sch Comp Sci & Informat Dublin Ireland

ISBN: (纸本)9781479928934

This paper exploits the connection between minimum-distortion perfect counterforensics and maximum-rate perfect steganography in order to provide the optimum solution to the first of these problems, in the case in which the forensic detector solely uses first-order statistics. The solution relies on Slepian's variant I permutation codes, which had previously been shown to implement maximum-rate perfect steganography when the host is memoryless (equivalently, when the steganographic detector only uses first-order statistics). Additionally, we demonstrate a blind counterforensic strategy made possible by permutation decoding, which may also find application in image processing.

关键词： Counterforensics steganography permutation coding histogram-based forensics histogram specification

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Asymptotically Optimum Perfect Universal Steganography of Finite Memoryless Sources

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IEEE TRANSACTIONS ON INFORMATION THEORY 2018年第2期64卷 1199-1216页

作者： Balado, Felix Haughton, David Univ Coll Dublin Sch Comp Sci Dublin 4 Ireland Ctr Appl Data Analyt Res Belfield Off Pk Dublin 4 Ireland

A solution to the problem of asymptotically optimum perfect universal steganography of finite memoryless sources with a passive warden is provided, which is then extended to contemplate a distortion constraint. The solution rests on the fact that Slepian's Variant I permutation coding implements first-order perfect universal steganography of finite host signals with optimum embedding rate. The duality between perfect universal steganography with asymptotically optimum embedding rate and lossless universal source coding with asymptotically optimum compression rate is evinced in practice by showing that permutation coding can be implemented by means of adaptive arithmetic coding. Next, a distortion constraint between the host signal and the information-carrying signal is considered. Such a constraint is essential whenever real-world host signals with memory (e.g., images, audio, or video) are decorrelated to conform to the memoryless assumption. The constrained version of the problem requires trading off embedding rate and distortion. Partitioned permutation coding is shown to be a practical way to implement this trade-off, performing close to an unattainable upper bound on the rate-distortion function of the problem.

关键词： Steganography source coding permutation coding arithmetic coding rate-distortion

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A generalized upper bound and a multilevel construction. for distance-preserving mappings

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IEEE TRANSACTIONS ON INFORMATION THEORY 2006年第8期52卷 3685-3695页

作者： Swart, Theo G. Ferreira, Hendrik C. Univ Johannesburg Dept Elect & Elect Engn ZA-2006 Auckland Pk South Africa

A new general upper bound is derived on the sum of the Hamming distances between sequences when mapping from one set of sequences to another. It is shown that a similar upper bound for mappings from binary sequences to permutation sequences is a special case of this upper bound and this is used to evaluate known mappings. Also, new distance-preserving mappings (DPMs) from binary sequences to permutation sequences are presented, based on a multilevel construction. In addition to explicit distance-conserving mappings, distance-increasing, and distance-reducing mappings are also presented. Several of the new DPMs attain the upper bound.

关键词： code constructions distance bounds distance-preserving mappings (DPMs) Hamming distance permutation coding

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Using graphs for the analysis and construction of permutation distance-preserving mappings

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第2期54卷 910-916页

作者： Swart, Theo G. Ferreira, Hendrik C. Ouahada, Khmaies Univ Johannesburg Dept Elect & Elect Engn Sci ZA-2006 Johannesburg South Africa

A new way of looking at permutation distance-preserving mappings (DPMs) is presented by making use of a graph representation. The properties necessary to make such a graph distance-preserving, are also investigated. Further, this new knowledge is used to analyze previous constructions, as well as to construct a new general mapping algorithm for a previous multilevel construction.

关键词： code constructions distance-preserving mappings (DPMs) graphs permutation coding

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Frequency permutation Subsets for Joint Radar and Communication

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2024年第2期23卷 1143-1157页

作者： Dayarathna, Shalanika Senanayake, Rajitha Smith, Peter Evans, Jamie Univ Melbourne Dept Elect & Elect Engn Melbourne Vic 3010 Australia Victoria Univ Wellington Sch Math & Stat Wellington 6140 New Zealand

This paper focuses on waveform design for joint radar and communication systems and presents a new subset selection process to improve the communication error rate performance and global accuracy of radar sensing of the permutation based random stepped frequency radar waveform. An optimal communication receiver based on integer programming is proposed to handle any subset of permutations followed by a more efficient sub-optimal receiver based on the Hungarian algorithm. Considering optimal maximum likelihood detection, the block error rate is analyzed under both additive white Gaussian noise and correlated Rician fading. We propose two methods to select a permutation subset with an improved block error rate and an efficient encoding scheme to map the information symbols to selected permutations under these subsets. From the radar perspective, the ambiguity function is analyzed with regards to the local and the global accuracy of target detection. Furthermore, a subset selection method to reduce peak-to-sidelobe ratio (PSLR) is proposed by extending the properties of Costas arrays. Finally, the process of remapping the frequency tones to the symbol set used to generate permutations is introduced as a method to improve both the communication and radar performances of the selected permutation subset.

关键词： Radar OFDM Receivers Sensors Frequency modulation Encoding Symbols Joint radar and communications permutation coding error rate Hamming distance maximum likelihood ambiguity function peak-to-sidelobe ratio subset selection

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A RANKING METHOD FOR RATING THE PERFORMANCES OF permutation CODES

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SAIEE AFRICA RESEARCH JOURNAL 2017年第1期108卷 12-23页

作者： Ogunyanda, K. Swart, T. G. Univ Johannesburg Dept Elect & Elect Engn Sci ZA-2006 Auckland Pk South Africa

Minimum Hamming distance, dm, has been widely used as the yardstick for the performance of permutation codes (PCs). However, a number of PCs with the same dm and cardinality can have different performances, even if they have the same distance optimality. Since PC is a robust channel coding scheme in power line communications applications, we present a simple and fast ranking method that predicts the relative performance of PCs, by using the information extracted from their Hamming distance distributions. This tool is useful for selecting an efficient PC codebook out of a number of similar ones.

关键词： Channel coding Hamming distance distribution permutation coding Power line communications Ranking method

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permutation sequences and coded PAM signals with spectral nulls at rational submultiples of the symbol frequency

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CRYPTOGRAPHY AND COMMUNICATIONS-DISCRETE-STRUCTURES BOOLEAN FUNCTIONS AND SEQUENCES 2011年第2期3卷 87-108页

作者： Ouahada, Khmaies Swart, Theo G. Ferreira, Hendrik C. Univ Johannesburg Dept Elect & Elect Engn Sci ZA-2006 Auckland Pk South Africa

Coded PAM signals with spectral nulls at rational submultiples of the symbol frequency are presented. Spectral shaping using permutation symbols and distance-preserving mappings (DPMs) are two techniques presented in this paper to design codes with better error correction capability, which make them achieve a significant decoding gain compared to other published codes. The use of Viterbi decoding algorithm, gives these new codes an advantage with their property of no error propagation. The well shaped power spectral densities of these new codes may overcome some communications problem like zero frequency components.

关键词： Code constructions Distance-preserving mappings permutation coding Pulse amplitude modulation Spectral shaping

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permutation CODES AND STEGANOGRAPHY

PERMUTATION CODES AND STEGANOGRAPHY

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IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Balado, Felix Haughton, David Univ Coll Dublin Sch Comp Sci & Informat Dublin Ireland

ISBN: (纸本)9781479903566

We show that Slepian's Variant I permutation codes implement first-order perfect steganography (i.e., histogram-preserving steganography). We give theoretical expressions for the embedding distortion, embedding rate and embedding efficiency of permutation codes in steganography, which demonstrate that these codes conform to prior analyses of the properties of capacity-achieving perfect stegosystems with a passive warden. We also propose a modification of adaptive arithmetic coding that near optimally implements permutation coding with a low complexity, confirming all our theoretical predictions. Finally we discuss how to control the embedding distortion. permutation coding turns out to be akin to Sallee's model-based steganography, and to supersede both this method and LSB matching.

关键词： permutation coding histogram preservation arithmetic coding model-based steganography LSB matching

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