Orthogonal transforms and their application to image coding

Imperial Users onl

ON SOME RESULTS OF NUMBER THEORETIC TRANSFORM (NTT) -PERIODIC SIGNAL

The interest givento the application of Number Theoretic Transforms (NTT’s)to digital signal processing has not ceasegrow. These transformations are used to improve convolutions, where arithmetic operations give a modulo an integerresIn order to understand the domain of the NTT, we have to show their powerful properties and exploit them in diffeapplications such as in signal processing

Glosarium Matematika

273 p.; 24 cm

Implementation of Digital Filters Using Fermat Number Transform On TMS320C30 Digital Signal Processor

Precise systems design, equipment standardization, and stability of performance characteristics are among the many advantages digital techniques can offer in signal processing. Earlier research in this field of study has contributed much to many of the modern day conveniences. Many of these contributions focus on improving computational efficiency of discrete Fourier transform (DFT) calculation. However, there are many shortcomings; therefore number theoretic transform (NTT) is proposed. This study implements three digital filters using one of the NTT, namely the Fermat number transform (FNT), and DFT. It compares the execution time, number of operation, and memory requirement for both implementations. Implementation of both types of filters employs the radix-2 fast Fourier transform (FFT) . This study proposes a modified diminished-one number system in implementing FNT. The number system was originally proposed by Leibowitz. I would like to take this opportunity to thank my major advisor, Dr. Lu, for the encouragement she has offered over the years. Her patience and constructive guidance has been very helpful. Also, I would like to thank Dr. Teague for his kindness in giving me access to his digital signal processing laboratory, where most of the work in this study was done. My appreciation also goes to my parents for their continuous supportComputer Scienc

Design of tch-type sequences for communications

This thesis deals with the design of a class of cyclic codes inspired by TCH codewords. Since TCH codes are linked to finite fields the fundamental concepts and facts about abstract algebra, namely group theory and number theory, constitute the first part of the thesis. By exploring group geometric properties and identifying an equivalence between some operations on codes and the symmetries of the dihedral group we were able to simplify the generation of codewords thus saving on the necessary number of computations. Moreover, we also presented an algebraic method to obtain binary generalized TCH codewords of length N = 2k, k = 1,2, . . . , 16. By exploring Zech logarithm’s properties as well as a group theoretic isomorphism we developed a method that is both faster and less complex than what was proposed before. In addition, it is valid for all relevant cases relating the codeword length N and not only those resulting from N = p

Number theoretic transform implementation using microprocessors

Since 1974 considerable interest has been shown in the literature in the topic of number theoretic transforms. These transforms provide an efficient integer processing technique for convolution. Microprocessors are suited to integer processing particularly for applications where the required processing load is small. It was therefore a natural step to investigate and tailor the properties of number theoretic transforms to the capabilities of microprocessors to provide cheap and compact processors using efficient signal processing algorithms. It was found that efficient number theoretic transforms could be defined using the Modulus M = 65521 and this is especially convenient for a microprocessor implementation. Relevant aspects of modular arithmetic are investigated. The techniques developed are extended to allow for complex signal processing. In conclusion it is shown that number theoretic transforms can be used to encode and decode Reed-Soloman error correcting codes

Number theoretic techniques applied to algorithms and architectures for digital signal processing

Many of the techniques for the computation of a two-dimensional convolution of a small fixed window with a picture are reviewed. It is demonstrated that Winograd's cyclic convolution and Fourier Transform Algorithms, together with Nussbaumer's two-dimensional cyclic convolution algorithms, have a common general form. Many of these algorithms use the theoretical minimum number of general multiplications. A novel implementation of these algorithms is proposed which is based upon one-bit systolic arrays. These systolic arrays are networks of identical cells with each cell sharing a common control and timing function. Each cell is only connected to its nearest neighbours. These are all attractive features for implementation using Very Large Scale Integration (VLSI). The throughput rate is only limited by the time to perform a one-bit full addition. In order to assess the usefulness to these systolic arrays a 'cost function' is developed to compare them with more conventional techniques, such as the Cooley-Tukey radix-2 Fast Fourier Transform (FFT). The cost function shows that these systolic arrays offer a good way of implementing the Discrete Fourier Transform for transforms up to about 30 points in length. The cost function is a general tool and allows comparisons to be made between different implementations of the same algorithm and between dissimilar algorithms. Finally a technique is developed for the derivation of Discrete Cosine Transform (DCT) algorithms from the Winograd Fourier Transform Algorithm. These DCT algorithms may be implemented by modified versions of the systolic arrays proposed earlier, but requiring half the number of cells

Implementation and analysis of the generalised new Mersenne number transforms for encryption

PhD ThesisEncryption is very much a vast subject covering myriad techniques to conceal and safeguard data and communications. Of the techniques that are available, methodologies that incorporate the number theoretic transforms (NTTs) have gained recognition, specifically the new Mersenne number transform (NMNT). Recently, two new transforms have been introduced that extend the NMNT to a new generalised suite of transforms referred to as the generalised NMNT (GNMNT). These two new transforms are termed the odd NMNT (ONMNT) and the odd-squared NMNT (O2NMNT). Being based on the Mersenne numbers, the GNMNTs are extremely versatile with respect to vector lengths. The GNMNTs are also capable of being implemented using fast algorithms, employing multiple and combinational radices over one or more dimensions. Algorithms for both the decimation-in-time (DIT) and -frequency (DIF) methodologies using radix-2, radix-4 and split-radix are presented, including their respective complexity and performance analyses. Whilst the original NMNT has seen a significant amount of research applied to it with respect to encryption, the ONMNT and O2NMNT can utilise similar techniques that are proven to show stronger characteristics when measured using established methodologies defining diffusion. Analyses in diffusion using a small but reasonably sized vector-space with the GNMNTs will be exhaustively assessed and a comparison with the Rijndael cipher, the current advanced encryption standard (AES) algorithm, will be presented that will confirm strong diffusion characteristics. Implementation techniques using general-purpose computing on graphics processing units (GPGPU) have been applied, which are further assessed and discussed. Focus is drawn upon the future of cryptography and in particular cryptology, as a consequence of the emergence and rapid progress of GPGPU and consumer based parallel processing