Vector#
Module to compute filters on vector/direction fields
Used for filtering orientation and fiber data.
- alignment(vectors, structural_element, structural_element_offset=None, weights=None, sink=None)[source]#
Compute alignment of central vector with neighboring vectors.
Arguments
- vectorsarray
Input vector field array.
- structural_element: array or str
Structural element specification.
- structural_element_offsettuple or None
Structural element offset
- weightsNone or array
Weights for each vector in the vector field.
- sinkarray
Output, if None, a new array is allocated.
Returns
- sinkarray
Filtered output.
Algorithm#
- For each central voxel
compute a set of weights to neighboring vectors via the scalar product of the central vector with the structural element vectors
compute the scalar product of the central vector with the neighbouring vectors
from the weighed sum
- orientation(vectors, structural_element, structural_element_offset=None, weights=None, sink=None)[source]#
Compute orientation alignment of central vector with neighboring vectors.
Arguments
- vectorsarray
Input vector field array.
- structural_element: array or str
Structural element specification.
- structural_element_offsettuple or None
Structural element offset
- weightsNone or array
Weights for each vector in the vector field.
- sinkarray
Output, if None, a new array is allocated.
Returns
- sinkarray
Filtered output.
Algorithm#
- For each central voxel
compute a set of matched orientation weights to neighboring vectors via the absolute value scalar product of the central vector with the structural element vectors (e.g. direction vectors from center), and further multiply by the input weights for the vectors.
compute the absolute value of the scalar product of the central vector with the neighbouring vectors
from the weighed sum
- orientation_ellipsoid(vectors, weights=None, max_radius=5, scales=(2, 1), sink=None)[source]#
Compute orientation alignment of central vector with neighboring vectors.
Arguments
- vectorsarray
Input vector field array.
- weightsNone or array
Weights for each vector in the vector field.
- max_radiusfloat
The maximal radius of the ellipse
- scalestuple or list
A tuple (s1,s2) with s1 for the scale of the mayor axis and s2 the scale for the 2 minor axes of the ellipsoid.
- sinkarray
Output, if None, a new array is allocated.
Returns
- sinkarray
Filtered output.
Algorithm#
- For each central voxel
compute a set of matched orientation weights to neighboring vectors via the absolute value scalar product of the central vector with the structural element vectors (e.g. direction vectors from center), and further multiply by the input weights for the vectors.
compute the absolute value of the scalar product of the central vector with the neighbouring vectors
from the weighed sum
- similarity(vectors, structural_element, structural_element_offset=None, weights=None, sink=None)[source]#
Compute sum of scalar products of the center vector with neighbouring vectors defined by the structural element.
Arguments
- vectorsarray
Input vector field array.
- structural_element: array or str
Structural element specification.
- structural_element_offsettuple or None
Structural element offset
- weightsNone or array
Weights for each vector in the vector field.
- sinkarray
Output, if None, a new array is allocated.
Returns
- sinkarray
Filtered output.
Algorithm#
For each center voxel compute the scalar products of the center vector with the neighbouring vectors defined by the structural element and sum.