medpy.filter.noise.immerkaer_local#

medpy.filter.noise.immerkaer_local(input, size, output=None, mode='reflect', cval=0.0)[source]#

Estimate the local noise.

The input image is assumed to have additive zero mean Gaussian noise. The Immerkaer noise estimation is applied to the image locally over a N-dimensional cube of side-length size. The size of the region should be sufficiently high for a stable noise estimation.

Parameters:
inputarray_like

Array of which to estimate the noise.

sizeinteger

The local region’s side length.

outputndarray, optional

The output parameter passes an array in which to store the filter output.

mode{‘reflect’, ‘constant’, ‘nearest’, ‘mirror’, ‘wrap’}, optional

The mode parameter determines how the array borders are handled, where cval is the value when mode is equal to ‘constant’. Default is ‘reflect’

cvalscalar, optional

Value to fill past edges of input if mode is ‘constant’. Default is 0.0

Returns:
sigmasarray_like

Map of the estimated standard deviation of the images Gaussian noise per voxel.

See also

immerkaer

Notes

Does not take the voxel spacing into account. Works good with medium to strong noise. Tends to underestimate for low noise levels.