Fourier

These two functions impliment the system of elliptical Fourier shape descriptors first described by Kuhl and Giardina in "Elliptic Fourier features of a closed contour" Computer Graphics and Image Processing 18:236-258 1982. fEfourier is the forward transform which creates a "shape spectrum" of a...

This demonstration is intended for people who know something about the theory of the discrete Fourier transform, and who would find it helpful to see some its properties demonstrated graphically, using a programming language.The demonstration shows the form of the Fourier components of a signal...

This is a tidied up version of Adam Wilmer's Fourier-Mellin transform for simple image rotation, scale and translation. No GUI is included and some code is cribbed directly from his implementation. I'm totally new to Matlab, so please excuse any coding faux-pas I have committed here.


Platforms: Matlab

Partial sums of Fourier terms for a function with jumps in value or derivative converge poorly, because of the Gibbs phenomenon. This file uses the Fourier coefficients, and locations of the singularities, to construct a different approximation that converges spectrally. For details, see T. A....


Platforms: Matlab

ifilter(x,y) or ifilter(y) or ifilter([x y]) or ry=ifilter(x,y,center,width,shape,plotmode,filtermode)Keyboard-operated interactive Fourier filter function for time-series signal (x,y), with keyboard controls that allow you to adjust the filter parameters continuously while observing the effect...


Platforms: Matlab

Program FFTSIGMA plots Fourier series representations with sigma approximation. The figures show effects of the number of series terms and use of Lanczos sigma factors to smooth Gibbs oscillations. The Fourier series of a periodic function with period px has the approximate form: f(x) = sum(...


Platforms: Matlab

DFT transforms one function into another, which is called the frequency domain representation, or simply the DFT, of the original function (which is often a function in the time domain). But the DFT requires an input function that is discrete and whose non-zero values have a limited (finite)...


Platforms: Matlab

Implementation of Fast Fourier Transform based Homogenization for heterogeneous materials dealing with electric or heat conductiviy. It takes the values of conductivity at regular grid of periodic unit cell that represents the material and produces the distribution of local fields such as...


Platforms: Matlab

The Fourier transform takes a signal in the time domain and maps it, without loss of information, into the frequency domain. The frequency domain representation is exactly the same signal, in a different form. The inverse Fourier transform(IDFT) maps the signal back from the frequency domain into...


Platforms: Matlab

This submission contains a collection of codes in different programming languages that implement the analytical framework proposed inKoay CG, Sarlls JE, doOCozarslan E. * Three Dimensional Analytical Magnetic Resonance Imaging Phantom in the Fourier Domain. Magn Reson Med. 58: 430-436 (2007)The...


Platforms: Matlab

The expected performance of a stock depends on quality of the company, market evaluation of its stock, and macroeconomic environment. Also general market current condition is a significant contributing factor in the stock performance. So that it is clear that a good investing decision should be...


Platforms: Windows

GFourier can help you use Fourier Analysis for image restoration. GFourier calculates the Fourier Transform of a given image and allows the use of filters in the frequency domain. The Inverse Fourier Transform is then used to substitute original image.. Get GFourier at SourceForge.net. Fast,...


Platforms: *nix

This program transforms the images and the sounds using single BIG Fourier Transforms (or DCT/DST,etc.). It produces very interesting and strange effects and allows you to transform sounds to images and vice-versa. To see what it does see the examples .


Platforms: *nix

PDL::FFTW is a PDL interface to the Fastest Fourier Transform in the West v2.x. This is a means to interface PDL with the FFTW library. Its similar to the standard FFT routine but its usually faster and has support for real transforms. It works well for the types of PDLs for which was the...


Platforms: *nix

FFT_Plugin is a REALBasic plugin designed to do direct and inverse Fast Fourier Transform. Windowing included with rectangular, triangular, Haming, Hanning, Welch, Blackman. compatible MacOS Classic (PPC,68k), MacOSX. Include FFT 2D. What's new in this version: Now is Universal Binary.


Platforms: Mac

This program calculates the non-destructive zoom Fast Fourier transform of a time history.The input file must be time(sec) and amplitude(units)Reference: Randall, Frequency Analysis, Bruel & Kjaer, page 170.


Platforms: Matlab

Radix 2 FFT using Decimation in FrequencyTruly Appreciates the Wonder Geniuses Joseph Fourier & Cooley Tuckey


Platforms: Matlab

This function returns N point DFT samples of 2dw band of Fourier transform of a sequence. Typically, fft() returns N samples of Fourier transform ranging from 0 to 2pi. This function takes the N-point DFT samples and returns N-point samples corresponding to frequency band wc-dw to wc+dw.


Platforms: Matlab

[cg, psg] = crandn(rgau,m)Generate correlated Gaussian sequences by Fourier synthesis.Input parameters:rgau = correlation function - length n/2m = number of realisationsOutput:cg = m x n matrix containing m sequences of n correlated variates from a zero mean, unit variance normal distributionpsg...


Platforms: Matlab

Split the signal S(SPACE,TIME) into its downward/upward space propagating and stationnary components via a 2D Fourier decomposition. S is a (SPACE,TIME) matrix. We eventually proceed to a space and/or time filtering. DT,DX are temporal and space step. PERIOD=[Tmin Tmax] and WAVELENGTH=[Xmin Xmax]...


Platforms: Matlab