BUILT-IN MATHEMATICA SYMBOL

LowpassFilter

LowpassFilter[data, c]
applies a lowpass filter with a cutoff frequency to an array of data.

LowpassFilter[data, c, n]
uses a filter kernel of length n.

LowpassFilter[data, c, n, wfun]
applies a smoothing window wfun to the filter kernel.

Details and OptionsDetails and Options

• LowpassFilter works with arbitrary-rank numerical arrays as well as with 3D and 2D images, operating separately on each channel.
• When applied to images and multidimensional arrays, filtering is applied successively to each dimension, starting at level 1. LowpassFilter[data, {c1, c2, ...}] uses the frequency for the dimension.
• LowpassFilter[data, c] uses a filter kernel length and smoothing window suitable for the cutoff frequency and the input data.
• Typical windows include:
•  BlackmanWindow smoothing with a Blackman window DirichletWindow no smoothing HammingWindow smoothing with a Hamming window {v1,v2,...} use a window with values f create a window by sampling f over the range and
• LowpassFilter[data, c] takes a SampleRate option that specifies the sampling rate of the data. With SampleRate->r, the cutoff frequency should be between 0 and r×. »
• By default, SampleRate->1 is assumed for images as well as data.
• LowpassFilter works with SampledSoundList. With SampledSoundList[list, r], SampleRate->r is used.
• For multichannel sound and image objects, each channel is processed separately.
• LowpassFilter takes a Padding option that specifies the padding values to use on the sides of the input.
• The default setting is Padding->"Fixed", corresponding to repetitions of the elements on each side.

ExamplesExamplesopen allclose all

Basic Examples (3)Basic Examples (3)

Lowpass filtering of a unit step sequence:

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Lowpass filtering of a noisy sinusoidal sequence:

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Lowpass filtering of an image:

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