Science / Spiders / Low-Pass Filtration: multiplication of the Fourier transform of an image with a 2D function ('the filter') that attenuates amplitudes at high spatial frequencies k. This has the result of blurring the image, and of eliminating sharp edges and noise. Low-pass filtration is routinely used to limit the information in a reconstruction to the reproducible resolution, as found by resolution criteria (see Fourier Shell Correlation, Differential Phase Residual). [See High-pass filtration, regarding SPIDER operations FF and FQ].
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Entertainment / Photography / Neutral Filtration: In color printing is the filtration at which color balance is achieved, rendering a neutral gray ion the film image as a neutral gray on the photographic paper. MORE
Science / Spiders / Wiener Filtration: application of the Wiener filter, designed to restore a signal in the presence of noise in an optimal way, in the least-square sense. MORE
Science / Spiders / Low-Pass Filtration: multiplication of the Fourier transform of an image with a 2D function ('the filter') that attenuates amplitudes at high spatial frequencies k. This has the result of blurring the image, and of elimin MORE