The cosine roll-off filter is commonly used for simple high-pass or low-pass operations. This is because an abrupt cut-off filter causes ringing in the resulting output data. The Cosine roll-off mitigates this artifact by introducing a gradual drop over a range. The desired cut-off wavelength resides within this range, but need not be centered on the range. If you observe ringing, you can reduce the artifact by widening the separation between the short and long wavelengths, or decreasing the degree of the filter.

Camerasensor

For ease of use and interpretation, the user is prompted to enter the cutoffs in units of wavelength, starting with the small wavelength. These are internally translated to wavenumbers for processing. In the illustration below the filter is portrayed in the Fourier domain, and as a result the horizontal axis is in units of Wavenumber. Wavenumbers are the inverse of wavelengths.

CMOSsensor

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To filter out the noise or obtain the regional signature of the field, select "Low" pass. To obtain the near surface signature of the field, select the "High" pass option (Default is Low).

The cosine roll-off filter (see illustration) spreads the cut-off over a range in a smooth gradual fashion using a cosine function. This range is bound by two user specified wavelengths.