smpy.filters.processing.schirmer_filter

smpy.filters.processing.schirmer_filter(scaled_radii, scale)[source]

Compute Schirmer filter values for given scaled radii.

Calculate the Schirmer filter function values used in aperture mass mapping for optimal mass reconstruction with suppressed noise.

Parameters:

  • scaled_radii (numpy.ndarray) – Radius values scaled by the aperture radius.

  • scale (float) – Scale radius of the filter in pixels.

Returns:

filter_values – Filter values at the given radii positions.

Return type:

numpy.ndarray

Notes

Implements the Q function filter as defined in McCleary et al. 2020: Q(x) = [1/(1 + e^(a-bx) + e^(dx-c))] * [tanh(x/x_c)/(pi*Rs^2*(x/x_c))]

Parameters are set to: a = 6, b = 150, c = 47, d = 50, x_c = 0.12 (Hetterscheidt et al. 2005)

References