VLFeat - Documentation > MATLAB API > IMOP - vl_imwhiten

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Documentation> MATLAB API> IMOP - vl_imwhiten

J = VL_IMWHITEN(I,ALPHA) approximatively whitens the power spectrum of the natural image I. The algorithm assumes that the modulus of the spectrum decays as 1/f^ALPHA (f is the frequency).

VL_IMWHITEN(I) uses ALPHA=1 (a typical value for natural images).

VL_IMWHITEN(I,ALPHA,CUTOFF) also applies a low-pass filter with cutoff frequency equal to CUTOFF x FN, where FN is the Nyquist frequency (half of the sampling frequency).

See also: VL_HELP().