def subsample_streamlines(streamlines,
clustering_threshold=6.,
removal_distance=2.):
""" Subsample a group of streamlines (should be used on streamlines from a single bundle or similar structure).
Streamlines are first clustered using `clustering_threshold`, then for each cluster, similar streamlines (closer than `removal_distance`) are removed.
Parameters
----------
streamlines : `ArraySequence` object
Streamlines to subsample
clustering_threshold : float
distance threshold for clustering (in the space of the tracks)
removal_distance : float
distance threshold for removal (in the space of the tracks)
Returns
-------
`ArraySequence` object
Downsampled streamlines
"""
output_streamlines = []
qb = QuickBundles(streamlines, dist_thr=clustering_threshold, pts=20)
for i in range(len(qb.centroids)):
temp_streamlines = qb.label2tracks(streamlines, i)
output_streamlines.extend(
remove_similar_streamlines(temp_streamlines,
removal_distance=removal_distance))
return output_streamlines
