31 research outputs found
Two dimensional symmetric and antisymmetric generalizations of sine functions
Properties of 2-dimensional generalizations of sine functions that are
symmetric or antisymmetric with respect to permutation of their two variables
are described. It is shown that the functions are orthogonal when integrated
over a finite region of the real Euclidean space, and that they are
discretely orthogonal when summed up over a lattice of any density in .
Decomposability of the products of functions into their sums is shown by
explicitly decomposing products of all types. The formalism is set up for
Fourier-like expansions of digital data over 2-dimensional lattices in .
Continuous interpolation of digital data is studied.Comment: 12 pages, 5 figure
Comments on ‘Area and power efficient DCT architecture for image compression’ by Dhandapani and Ramachandran
A new VLSI algorithm and architecture for the hardware implementation of type IV discrete cosine transform using a pseudo-band correlation structure
An algebraic method for synthesizing fast algorithms of discrete cosine transform of arbitrary size
The eigen-structures of real (skew) circulant matrices with some applications
The circulant matrices and skew-circulant matrices are two special classes of Toeplitz matrices and play vital roles in the computation of Toeplitz matrices.
In this paper, we focus on real circulant and skew-circulant matrices. We first investigate their real Schur forms, which are closely related to the family of discrete cosine transform (DCT) and discrete sine transform (DST). Using those real Schur forms, we then develop some fast algorithms for computing real circulant, skew-circulant and Toeplitz matrix-real vector multiplications. Also, we develop a DCT-DST version of circulant and skew-circulant splitting (CSCS) iteration for real positive definite Toeplitz systems. Compared with the fast Fourier transform (FFT) version of CSCS iteration, the DCT-DST version is more efficient and saves a half storage. Numerical experiments are presented to illustrate the effectiveness of our method.The authors would like to thank the supports of the National Natural Science Foundationof China under Grant No. 11371075, the Hunan Key Laboratory of Mathematical Modeling and Analysis inEngineering, and the Portuguese Funds through FCT-Fundação para a Ciência, within the Project UID/ MAT/00013/2013