Classes and functions for generalized q-sampling
finds the ‘vertices’ in the equatorial zone conjugate to ‘pole’ with width half ‘width’ degrees
Normalize quantitative anisotropy.
Used mostly with GQI rather than GQI2.
Parameters: | qa : array, shape (X, Y, Z, N)
max_qa : float,
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Returns: | nqa : array, shape (x, Y, Z, N)
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Notes
Normalized quantitative anisotropy has the very useful property to be very small near gray matter and background areas. Therefore, it can be used to mask out white matter areas.
non-parametric anisotropy
Nimmo-Smith et. al ISMRM 2011
find ‘vertices’ within the cone of ‘width’ degrees around ‘pole’
finds the ‘vertices’ in the equatorial band around the ‘pole’ of radius ‘width’ degrees
Part of the GQI2 integral
Eq.8 in the referenced paper by Yeh et al. 2010
maps a 3-vector into the z-upper hemisphere