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  2. Spectral method - Wikipedia

    en.wikipedia.org/wiki/Spectral_method

    Compute the Fourier transform (b j,k) of g.Compute the Fourier transform (a j,k) of f via the formula ().Compute f by taking an inverse Fourier transform of (a j,k).; Since we're only interested in a finite window of frequencies (of size n, say) this can be done using a fast Fourier transform algorithm.

  3. Fourier transform - Wikipedia

    en.wikipedia.org/wiki/Fourier_transform

    In mathematics, the Fourier transform (FT) is an integral transform that takes a function as input and outputs another function that describes the extent to which various frequencies are present in the original function. The output of the transform is a complex-valued function of frequency.

  4. Bailey's FFT algorithm - Wikipedia

    en.wikipedia.org/wiki/Bailey's_FFT_algorithm

    Bailey algorithm (4-step version) for a 16-point FFT The Bailey's FFT (also known as a 4-step FFT ) is a high-performance algorithm for computing the fast Fourier transform (FFT). This variation of the Cooley–Tukey FFT algorithm was originally designed for systems with hierarchical memory common in modern computers (and was the first FFT ...

  5. Gabor transform - Wikipedia

    en.wikipedia.org/wiki/Gabor_transform

    The Gabor transform, named after Dennis Gabor, is a special case of the short-time Fourier transform.It is used to determine the sinusoidal frequency and phase content of local sections of a signal as it changes over time.

  6. Fourier analysis - Wikipedia

    en.wikipedia.org/wiki/Fourier_analysis

    The discrete version of the Fourier transform (see below) can be evaluated quickly on computers using fast Fourier transform (FFT) algorithms. [8] In forensics, laboratory infrared spectrophotometers use Fourier transform analysis for measuring the wavelengths of light at which a material will absorb in the infrared spectrum.

  7. Gerchberg–Saxton algorithm - Wikipedia

    en.wikipedia.org/wiki/Gerchberg–Saxton_algorithm

    The pseudocode below performs the GS algorithm to obtain a phase distribution for the plane "Source", such that its Fourier transform would have the amplitude distribution of the plane "Target". The Gerchberg-Saxton algorithm is one of the most prevalent methods used to create computer-generated holograms .

  8. Spectral leakage - Wikipedia

    en.wikipedia.org/wiki/Spectral_leakage

    The Fourier transform of a function of time, s(t), is a complex-valued function of frequency, S(f), often referred to as a frequency spectrum.Any linear time-invariant operation on s(t) produces a new spectrum of the form H(f)•S(f), which changes the relative magnitudes and/or angles of the non-zero values of S(f).

  9. DFT matrix - Wikipedia

    en.wikipedia.org/wiki/DFT_matrix

    In this case, if we make a very large matrix with complex exponentials in the rows (i.e., cosine real parts and sine imaginary parts), and increase the resolution without bound, we approach the kernel of the Fredholm integral equation of the 2nd kind, namely the Fourier operator that defines the continuous Fourier transform. A rectangular ...