def zernike_moments(points,
faces,
order=10,
scale_input=True,
decimate_fraction=0,
decimate_smooth=0,
verbose=False):
"""
Compute the Zernike moments of a surface patch of points and faces.
Optionally decimate the input mesh.
Note::
Decimation sometimes leads to an error of "Segmentation fault: 11"
(Twins-2-1 left label 14 gives such an error only when decimated.)
Parameters
----------
points : list of lists of 3 floats
x,y,z coordinates for each vertex
faces : list of lists of 3 integers
each list contains indices to vertices that form a triangle on a mesh
order : integer
order of the moments being calculated
scale_input : bool
translate and scale each object so it is bounded by a unit sphere?
(this is the expected input to zernike_moments())
decimate_fraction : float
fraction of mesh faces to remove for decimation (0 for no decimation)
decimate_smooth : integer
number of smoothing steps for decimation
verbose : bool
print statements?
Returns
-------
descriptors : list of floats
Zernike descriptors
Examples
--------
>>> # Example 1: simple cube (decimation results in a Segmentation Fault):
>>> import numpy as np
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> points = [[0,0,0], [1,0,0], [0,0,1], [0,1,1],
... [1,0,1], [0,1,0], [1,1,1], [1,1,0]]
>>> faces = [[0,2,4], [0,1,4], [2,3,4], [3,4,5], [3,5,6], [0,1,7]]
>>> order = 3
>>> scale_input = True
>>> decimate_fraction = 0
>>> decimate_smooth = 0
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... decimate_fraction, decimate_smooth, verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.09189 0.09357 0.04309 0.06466 0.0382 0.04138]
Example 2: Twins-2-1 left postcentral pial surface -- NO decimation:
(zernike_moments took 142 seconds for order = 3 with no decimation)
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.guts.mesh import keep_faces
>>> from mindboggle.mio.fetch_data import prep_tests
>>> urls, fetch_data = prep_tests()
>>> label_file = fetch_data(urls['left_freesurfer_labels'], '', '.vtk')
>>> points, f1,f2, faces, labels, f3,f4,f5 = read_vtk(label_file)
>>> I22 = [i for i,x in enumerate(labels) if x==1022] # postcentral
>>> faces = keep_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> decimate_fraction = 0
>>> decimate_smooth = 0
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... decimate_fraction, decimate_smooth, verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.00471 0.0084 0.00295 0.00762 0.0014 0.00076]
Example 3: left postcentral + pars triangularis pial surfaces:
>>> from mindboggle.mio.vtks import read_vtk, write_vtk
>>> points, f1,f2, faces, labels, f3,f4,f5 = read_vtk(label_file)
>>> I20 = [i for i,x in enumerate(labels) if x==1020] # pars triangularis
>>> I22 = [i for i,x in enumerate(labels) if x==1022] # postcentral
>>> I22.extend(I20)
>>> faces = keep_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> decimate_fraction = 0
>>> decimate_smooth = 0
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... decimate_fraction, decimate_smooth, verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.00586 0.00973 0.00322 0.00818 0.0013 0.00131]
View both segments (skip test):
>>> from mindboggle.mio.plots import plot_surfaces # doctest: +SKIP
>>> from mindboggle.mio.vtks import rewrite_scalars # doctest: +SKIP
>>> scalars = -1 * np.ones(np.shape(labels)) # doctest: +SKIP
>>> scalars[I22] = 1 # doctest: +SKIP
>>> rewrite_scalars(label_file, 'test_two_labels.vtk', scalars,
... 'two_labels', scalars) # doctest: +SKIP
>>> plot_surfaces(vtk_file) # doctest: +SKIP
"""
import numpy as np
from mindboggle.guts.mesh import reindex_faces_0to1
from mindboggle.guts.mesh import decimate
from mindboggle.shapes.zernike.pipelines import DefaultPipeline as Pipeline
# Convert 0-indices (Python) to 1-indices (Matlab) for all face indices:
index1 = False # already done elsewhere in the code
if index1:
faces = reindex_faces_0to1(faces)
# Convert lists to numpy arrays:
if isinstance(points, list):
points = np.array(points)
if isinstance(faces, list):
faces = np.array(faces)
# ------------------------------------------------------------------------
# Translate all points so that they are centered at their mean,
# and scale them so that they are bounded by a unit sphere:
# ------------------------------------------------------------------------
if scale_input:
center = np.mean(points, axis=0)
points = points - center
maxd = np.max(np.sqrt(np.sum(points**2, axis=1)))
points /= maxd
# ------------------------------------------------------------------------
# Decimate surface:
# ------------------------------------------------------------------------
if 0 < decimate_fraction < 1:
points, faces, u1, u2 = decimate(points,
faces,
decimate_fraction,
decimate_smooth, [],
save_vtk=False)
# Convert lists to numpy arrays:
points = np.array(points)
faces = np.array(faces)
# ------------------------------------------------------------------------
# Multiprocessor pipeline:
# ------------------------------------------------------------------------
pl = Pipeline()
# ------------------------------------------------------------------------
# Geometric moments:
# ------------------------------------------------------------------------
G = pl.geometric_moments_exact(points, faces, order)
# ------------------------------------------------------------------------
# ------------------------------------------------------------------------
Z = pl.zernike(G, order)
# ------------------------------------------------------------------------
# Extract Zernike descriptors:
# ------------------------------------------------------------------------
descriptors = pl.feature_extraction(Z, order).tolist()
if verbose:
print("Zernike moments: {0}".format(descriptors))
return descriptors
def zernike_moments(points, faces, order=10, scale_input=True,
decimate_fraction=0, decimate_smooth=0, verbose=False):
"""
Compute the Zernike moments of a surface patch of points and faces.
Optionally decimate the input mesh.
Note::
Decimation sometimes leads to an error of "Segmentation fault: 11"
(Twins-2-1 left label 14 gives such an error only when decimated.)
Parameters
----------
points : list of lists of 3 floats
x,y,z coordinates for each vertex
faces : list of lists of 3 integers
each list contains indices to vertices that form a triangle on a mesh
order : integer
order of the moments being calculated
scale_input : bool
translate and scale each object so it is bounded by a unit sphere?
(this is the expected input to zernike_moments())
decimate_fraction : float
fraction of mesh faces to remove for decimation (0 for no decimation)
decimate_smooth : integer
number of smoothing steps for decimation
verbose : bool
print statements?
Returns
-------
descriptors : list of floats
Zernike descriptors
Examples
--------
>>> # Example 1: simple cube (decimation results in a Segmentation Fault):
>>> import numpy as np
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> points = [[0,0,0], [1,0,0], [0,0,1], [0,1,1],
... [1,0,1], [0,1,0], [1,1,1], [1,1,0]]
>>> faces = [[0,2,4], [0,1,4], [2,3,4], [3,4,5], [3,5,6], [0,1,7]]
>>> order = 3
>>> scale_input = True
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.09189 0.09357 0.04309 0.06466 0.0382 0.04138]
Example 2: Twins-2-1 left postcentral pial surface -- NO decimation:
(zernike_moments took 142 seconds for order = 3 with no decimation)
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.guts.mesh import keep_faces
>>> from mindboggle.mio.fetch_data import prep_tests
>>> urls, fetch_data = prep_tests()
>>> label_file = fetch_data(urls['left_freesurfer_labels'])
>>> points, f1,f2, faces, labels, f3,f4,f5 = read_vtk(label_file)
>>> I22 = [i for i,x in enumerate(labels) if x==1022] # postcentral
>>> faces = keep_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.00471 0.0084 0.00295 0.00762 0.0014 0.00076]
Example 3: left postcentral + pars triangularis pial surfaces:
>>> from mindboggle.mio.vtks import read_vtk, write_vtk
>>> points, f1,f2, faces, labels, f3,f4,f5 = read_vtk(label_file)
>>> I20 = [i for i,x in enumerate(labels) if x==1020] # pars triangularis
>>> I22 = [i for i,x in enumerate(labels) if x==1022] # postcentral
>>> I22.extend(I20)
>>> faces = keep_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> verbose = False
>>> descriptors = zernike_moments(points, faces, order, scale_input,
... verbose)
>>> print(np.array_str(np.array(descriptors),
... precision=5, suppress_small=True))
[ 0.00586 0.00973 0.00322 0.00818 0.0013 0.00131]
View both segments (skip test):
>>> from mindboggle.mio.plots import plot_surfaces
>>> scalars = -1 * np.ones(np.shape(labels))
>>> scalars[I22] = 1
>>> vtk_file = 'test_two_labels.vtk'
>>> # Note: mismatch in the following command:
>>> write_vtk(vtk_file, points, [],[], faces, scalars, 'scalars', 'int')
>>> plot_surfaces(vtk_file) # doctest: +SKIP
"""
import numpy as np
from mindboggle.guts.mesh import reindex_faces_0to1
from mindboggle.guts.mesh import decimate
from .pipelines import DefaultPipeline as ZernikePipeline
# Convert 0-indices (Python) to 1-indices (Matlab) for all face indices:
index1 = False # already done elsewhere in the code
if index1:
faces = reindex_faces_0to1(faces)
# Convert lists to numpy arrays:
if isinstance(points, list):
points = np.array(points)
if isinstance(faces, list):
faces = np.array(faces)
#-------------------------------------------------------------------------
# Translate all points so that they are centered at their mean,
# and scale them so that they are bounded by a unit sphere:
#-------------------------------------------------------------------------
if scale_input:
center = np.mean(points, axis=0)
points = points - center
maxd = np.max(np.sqrt(np.sum(points**2, axis=1)))
points = points / maxd
#-------------------------------------------------------------------------
# Decimate surface:
#-------------------------------------------------------------------------
if 0 < decimate_fraction < 1:
points, faces, u1,u2 = decimate(points, faces,
decimate_fraction, decimate_smooth, [], save_vtk=False)
# Convert lists to numpy arrays:
points = np.array(points)
faces = np.array(faces)
#-------------------------------------------------------------------------
# Multiprocessor pipeline:
#-------------------------------------------------------------------------
pl = ZernikePipeline()
#-------------------------------------------------------------------------
# Geometric moments:
#-------------------------------------------------------------------------
G = pl.geometric_moments_exact(points, faces, order)
#
Z = pl.zernike(G, order)
#-------------------------------------------------------------------------
# Extract Zernike descriptors:
#-------------------------------------------------------------------------
descriptors = pl.feature_extraction(Z, order).tolist()
if verbose:
print("Zernike moments: {0}".format(descriptors))
return descriptors
def zernike_moments(points,
faces,
order=10,
scale_input=True,
decimate_fraction=0,
decimate_smooth=0,
pl_cls=None):
"""
Compute the Zernike moments of a surface patch of points and faces.
Optionally decimate the input mesh.
Note::
Decimation sometimes leads to an error of "Segmentation fault: 11"
(Twins-2-1 left label 14 gives such an error only when decimated.)
Parameters
----------
points : list of lists of 3 floats
x,y,z coordinates for each vertex
faces : list of lists of 3 integers
each list contains indices to vertices that form a triangle on a mesh
order : integer
order of the moments being calculated
scale_input : Boolean
translate and scale each object so it is bounded by a unit sphere?
(this is the expected input to zernike_moments())
decimate_fraction : float
fraction of mesh faces to remove for decimation (0 for no decimation)
decimate_smooth : integer
number of smoothing steps for decimation
Returns
-------
descriptors : list of floats
Zernike descriptors
Examples
--------
>>> # Example 1: simple cube (decimation results in a Segmentation Fault):
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> points = [[0,0,0], [1,0,0], [0,0,1], [0,1,1], [1,0,1], [0,1,0], [1,1,1], [1,1,0]]
>>> faces = [[0,2,4], [0,1,4], [2,3,4], [3,4,5], [3,5,6], [0,1,7]]
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.0918881492369654,
0.09357431096617608,
0.04309029164656885,
0.06466432586854755,
0.03820155248327533,
0.04138011726544602]
>>> # Example 2: simple cube (with inner diagonal plane):
>>> # (decimation doesn't have any effect)
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> vtk_file = os.path.join(path, 'cube.vtk')
>>> faces, u1,u2, points, u3,u4,u5,u6 = read_vtk(vtk_file)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.0,
1.5444366221695725e-21,
0.0,
2.081366518964347e-21,
5.735003646768394e-05,
2.433866250546253e-21]
Arthur Mikhno's result:
0
0
0.2831
10.6997
2.1352
11.8542
>>> # Example 2.5: Parallelepiped.vtk:
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> vtk_file = os.path.join(path, 'Parallelepiped.vtk')
>>> faces, u1,u2, points, u3,u4,u5,u6 = read_vtk(vtk_file)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.2652000150907399,
0.27006648207389017,
6.902814314591948e-09,
7.901431343883835e-09,
0.12685697496878662,
5.560135951999606e-09]
Arthur Mikhno's result:
0.0251
0.0310
0.0255
0.0451
0.0189
0.0133
>>> # Example 3: Twins-2-1 left postcentral pial surface -- NO decimation:
>>> # (zernike_moments took 142 seconds for order = 3 with no decimation)
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.guts.mesh import remove_faces
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> label_file = os.path.join(path, 'arno', 'labels', 'lh.labels.DKT31.manual.vtk')
>>> faces, u1,u2, points, u3, labels, u4,u5 = read_vtk(label_file)
>>> I22 = [i for i,x in enumerate(labels) if x==22] # postcentral
>>> faces = remove_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.005558794553842859,
0.009838755429501177,
0.003512500896236744,
0.00899042745665395,
0.001672289910738449,
0.000919469614081582]
>>> # Example 5: left postcentral + pars triangularis pial surfaces:
>>> import os
>>> from mindboggle.mio.vtks import read_vtk, write_vtk
>>> from mindboggle.guts.mesh import remove_faces
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> label_file = os.path.join(path, 'arno', 'labels', 'lh.labels.DKT31.manual.vtk')
>>> faces, u1,u2, points, u3, labels, u4,u5 = read_vtk(label_file)
>>> I20 = [i for i,x in enumerate(labels) if x==20] # pars triangularis
>>> I22 = [i for i,x in enumerate(labels) if x==22] # postcentral
>>> I22.extend(I20)
>>> faces = remove_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.006591540793309832,
0.010749937070447451,
0.0034900573103799214,
0.008972460360983864,
0.0018220183025464518,
0.0016893113500293917]
>>> # View both segments:
>>> from mindboggle.mio.plots import plot_surfaces
>>> scalars = -1*np.ones(np.shape(labels))
>>> scalars[I22] = 1
>>> vtk_file = 'test_two_labels.vtk'
>>> write_vtk(vtk_file, points, [],[], faces, scalars, scalar_names='scalars', scalar_type='int')
>>> plot_surfaces(vtk_file)
"""
import numpy as np
from mindboggle.guts.mesh import reindex_faces_0to1
from mindboggle.guts.mesh import decimate
if pl_cls is None:
from .pipelines import DefaultPipeline as ZernikePipeline
else:
ZernikePipeline = pl_cls
# Convert 0-indices (Python) to 1-indices (Matlab) for all face indices:
index1 = False # already done elsewhere in the code
if index1:
faces = reindex_faces_0to1(faces)
# Convert lists to numpy arrays:
if isinstance(points, list):
points = np.array(points)
if isinstance(faces, list):
faces = np.array(faces)
#-------------------------------------------------------------------------
# Translate all points so that they are centered at their mean,
# and scale them so that they are bounded by a unit sphere:
#-------------------------------------------------------------------------
if scale_input:
center = np.mean(points, axis=0)
points = points - center
maxd = np.max(np.sqrt(np.sum(points**2, axis=1)))
points = points / maxd
#-------------------------------------------------------------------------
# Decimate surface:
#-------------------------------------------------------------------------
if 0 < decimate_fraction < 1:
points, faces, u1, u2 = decimate(points,
faces,
decimate_fraction,
decimate_smooth, [],
save_vtk=False)
# Convert lists to numpy arrays:
points = np.array(points)
faces = np.array(faces)
#-------------------------------------------------------------------------
# Multiprocessor pipeline:
#-------------------------------------------------------------------------
pl = ZernikePipeline()
#-------------------------------------------------------------------------
# Geometric moments:
#-------------------------------------------------------------------------
G = pl.geometric_moments_exact(points, faces, order)
#
Z = pl.zernike(G, order)
#-------------------------------------------------------------------------
# Extract Zernike descriptors:
#-------------------------------------------------------------------------
descriptors = pl.feature_extraction(Z, order).tolist()
return descriptors
def zernike_moments(points, faces, order=10, scale_input=True,
decimate_fraction=0, decimate_smooth=0, pl_cls=None):
"""
Compute the Zernike moments of a surface patch of points and faces.
Optionally decimate the input mesh.
Note::
Decimation sometimes leads to an error of "Segmentation fault: 11"
(Twins-2-1 left label 14 gives such an error only when decimated.)
Parameters
----------
points : list of lists of 3 floats
x,y,z coordinates for each vertex
faces : list of lists of 3 integers
each list contains indices to vertices that form a triangle on a mesh
order : integer
order of the moments being calculated
scale_input : Boolean
translate and scale each object so it is bounded by a unit sphere?
(this is the expected input to zernike_moments())
decimate_fraction : float
fraction of mesh faces to remove for decimation (0 for no decimation)
decimate_smooth : integer
number of smoothing steps for decimation
Returns
-------
descriptors : list of floats
Zernike descriptors
Examples
--------
>>> # Example 1: simple cube (decimation results in a Segmentation Fault):
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> points = [[0,0,0], [1,0,0], [0,0,1], [0,1,1], [1,0,1], [0,1,0], [1,1,1], [1,1,0]]
>>> faces = [[0,2,4], [0,1,4], [2,3,4], [3,4,5], [3,5,6], [0,1,7]]
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.0918881492369654,
0.09357431096617608,
0.04309029164656885,
0.06466432586854755,
0.03820155248327533,
0.04138011726544602]
>>> # Example 2: simple cube (with inner diagonal plane):
>>> # (decimation doesn't have any effect)
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> vtk_file = os.path.join(path, 'cube.vtk')
>>> faces, u1,u2, points, u3,u4,u5,u6 = read_vtk(vtk_file)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.0,
1.5444366221695725e-21,
0.0,
2.081366518964347e-21,
5.735003646768394e-05,
2.433866250546253e-21]
Arthur Mikhno's result:
0
0
0.2831
10.6997
2.1352
11.8542
>>> # Example 2.5: Parallelepiped.vtk:
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> vtk_file = os.path.join(path, 'Parallelepiped.vtk')
>>> faces, u1,u2, points, u3,u4,u5,u6 = read_vtk(vtk_file)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.2652000150907399,
0.27006648207389017,
6.902814314591948e-09,
7.901431343883835e-09,
0.12685697496878662,
5.560135951999606e-09]
Arthur Mikhno's result:
0.0251
0.0310
0.0255
0.0451
0.0189
0.0133
>>> # Example 3: Twins-2-1 left postcentral pial surface -- NO decimation:
>>> # (zernike_moments took 142 seconds for order = 3 with no decimation)
>>> import os
>>> from mindboggle.mio.vtks import read_vtk
>>> from mindboggle.guts.mesh import remove_faces
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> label_file = os.path.join(path, 'arno', 'labels', 'lh.labels.DKT31.manual.vtk')
>>> faces, u1,u2, points, u3, labels, u4,u5 = read_vtk(label_file)
>>> I22 = [i for i,x in enumerate(labels) if x==22] # postcentral
>>> faces = remove_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.005558794553842859,
0.009838755429501177,
0.003512500896236744,
0.00899042745665395,
0.001672289910738449,
0.000919469614081582]
>>> # Example 5: left postcentral + pars triangularis pial surfaces:
>>> import os
>>> from mindboggle.mio.vtks import read_vtk, write_vtk
>>> from mindboggle.guts.mesh import remove_faces
>>> from mindboggle.shapes.zernike.zernike import zernike_moments
>>> path = os.environ['MINDBOGGLE_DATA']
>>> label_file = os.path.join(path, 'arno', 'labels', 'lh.labels.DKT31.manual.vtk')
>>> faces, u1,u2, points, u3, labels, u4,u5 = read_vtk(label_file)
>>> I20 = [i for i,x in enumerate(labels) if x==20] # pars triangularis
>>> I22 = [i for i,x in enumerate(labels) if x==22] # postcentral
>>> I22.extend(I20)
>>> faces = remove_faces(faces, I22)
>>> order = 3
>>> scale_input = True
>>> zernike_moments(points, faces, order, scale_input)
[0.006591540793309832,
0.010749937070447451,
0.0034900573103799214,
0.008972460360983864,
0.0018220183025464518,
0.0016893113500293917]
>>> # View both segments:
>>> from mindboggle.mio.plots import plot_surfaces
>>> scalars = -1*np.ones(np.shape(labels))
>>> scalars[I22] = 1
>>> vtk_file = 'test_two_labels.vtk'
>>> write_vtk(vtk_file, points, [],[], faces, scalars, scalar_names='scalars', scalar_type='int')
>>> plot_surfaces(vtk_file)
"""
import numpy as np
from mindboggle.guts.mesh import reindex_faces_0to1
from mindboggle.guts.mesh import decimate
if pl_cls is None:
from .pipelines import DefaultPipeline as ZernikePipeline
else:
ZernikePipeline = pl_cls
# Convert 0-indices (Python) to 1-indices (Matlab) for all face indices:
index1 = False # already done elsewhere in the code
if index1:
faces = reindex_faces_0to1(faces)
# Convert lists to numpy arrays:
if isinstance(points, list):
points = np.array(points)
if isinstance(faces, list):
faces = np.array(faces)
#-------------------------------------------------------------------------
# Translate all points so that they are centered at their mean,
# and scale them so that they are bounded by a unit sphere:
#-------------------------------------------------------------------------
if scale_input:
center = np.mean(points, axis=0)
points = points - center
maxd = np.max(np.sqrt(np.sum(points**2, axis=1)))
points = points / maxd
#-------------------------------------------------------------------------
# Decimate surface:
#-------------------------------------------------------------------------
if 0 < decimate_fraction < 1:
points, faces, u1,u2 = decimate(points, faces,
decimate_fraction, decimate_smooth, [], save_vtk=False)
# Convert lists to numpy arrays:
points = np.array(points)
faces = np.array(faces)
#-------------------------------------------------------------------------
# Multiprocessor pipeline:
#-------------------------------------------------------------------------
pl = ZernikePipeline()
#-------------------------------------------------------------------------
# Geometric moments:
#-------------------------------------------------------------------------
G = pl.geometric_moments_exact(points, faces, order)
#
Z = pl.zernike(G, order)
#-------------------------------------------------------------------------
# Extract Zernike descriptors:
#-------------------------------------------------------------------------
descriptors = pl.feature_extraction(Z, order).tolist()
return descriptors
def zernike_moments(points, faces, order=10, scale_input=True,
decimate_fraction=0, decimate_smooth=0, verbose=False):
"""
Compute the Zernike moments of a surface patch of points and faces.
Optionally decimate the input mesh.
Note::
Decimation sometimes leads to an error of "Segmentation fault: 11"
(Twins-2-1 left label 14 gives such an error only when decimated.)
Parameters
----------
points : list of lists of 3 floats
x,y,z coordinates for each vertex
faces : list of lists of 3 integers
each list contains indices to vertices that form a triangle on a mesh
order : integer
order of the moments being calculated
scale_input : bool
translate and scale each object so it is bounded by a unit sphere?
(this is the expected input to zernike_moments())
decimate_fraction : float
fraction of mesh faces to remove for decimation (0 for no decimation)
decimate_smooth : integer
number of smoothing steps for decimation
verbose : bool
print statements?
Returns
-------
descriptors : list of floats
Zernike descriptors
"""
import numpy as np
from mindboggle.guts.mesh import reindex_faces_0to1
from mindboggle.guts.mesh import decimate
from mindboggle.shapes.zernike.pipelines import DefaultPipeline as Pipeline
# Convert 0-indices (Python) to 1-indices (Matlab) for all face indices:
index1 = False # already done elsewhere in the code
if index1:
faces = reindex_faces_0to1(faces)
# Convert lists to numpy arrays:
if isinstance(points, list):
points = np.array(points)
if isinstance(faces, list):
faces = np.array(faces)
# ------------------------------------------------------------------------
# Translate all points so that they are centered at their mean,
# and scale them so that they are bounded by a unit sphere:
# ------------------------------------------------------------------------
if scale_input:
center = np.mean(points, axis=0)
points = points - center
maxd = np.max(np.sqrt(np.sum(points ** 2, axis=1)))
points /= maxd
# ------------------------------------------------------------------------
# Decimate surface:
# ------------------------------------------------------------------------
if 0 < decimate_fraction < 1:
points, faces, u1, u2 = decimate(points, faces,
decimate_fraction, decimate_smooth, [], save_vtk=False)
# Convert lists to numpy arrays:
points = np.array(points)
faces = np.array(faces)
# ------------------------------------------------------------------------
# Multiprocessor pipeline:
# ------------------------------------------------------------------------
pl = Pipeline()
# ------------------------------------------------------------------------
# Geometric moments:
# ------------------------------------------------------------------------
G = pl.geometric_moments_exact(points, faces, order)
# ------------------------------------------------------------------------
# ------------------------------------------------------------------------
Z = pl.zernike(G, order)
# ------------------------------------------------------------------------
# Extract Zernike descriptors:
# ------------------------------------------------------------------------
descriptors = pl.feature_extraction(Z, order).tolist()
if verbose:
print("Zernike moments: {0}".format(descriptors))
return descriptors