fr/fr_env/lib/python3.8/site-packages/skimage/measure/_regionprops.py

1185 lines
43 KiB
Python

import inspect
from warnings import warn
from math import sqrt, atan2, pi as PI
import numpy as np
from scipy import ndimage as ndi
from scipy.spatial.distance import pdist
from . import _moments
from ._find_contours import find_contours
from ._marching_cubes_lewiner import marching_cubes
from ._regionprops_utils import euler_number, perimeter, perimeter_crofton
from functools import wraps
__all__ = ['regionprops', 'euler_number', 'perimeter', 'perimeter_crofton']
PROPS = {
'Area': 'area',
'BoundingBox': 'bbox',
'BoundingBoxArea': 'bbox_area',
'CentralMoments': 'moments_central',
'Centroid': 'centroid',
'ConvexArea': 'convex_area',
# 'ConvexHull',
'ConvexImage': 'convex_image',
'Coordinates': 'coords',
'Eccentricity': 'eccentricity',
'EquivDiameter': 'equivalent_diameter',
'EulerNumber': 'euler_number',
'Extent': 'extent',
# 'Extrema',
'FeretDiameterMax': 'feret_diameter_max',
'FilledArea': 'filled_area',
'FilledImage': 'filled_image',
'HuMoments': 'moments_hu',
'Image': 'image',
'InertiaTensor': 'inertia_tensor',
'InertiaTensorEigvals': 'inertia_tensor_eigvals',
'IntensityImage': 'intensity_image',
'Label': 'label',
'LocalCentroid': 'local_centroid',
'MajorAxisLength': 'major_axis_length',
'MaxIntensity': 'max_intensity',
'MeanIntensity': 'mean_intensity',
'MinIntensity': 'min_intensity',
'MinorAxisLength': 'minor_axis_length',
'Moments': 'moments',
'NormalizedMoments': 'moments_normalized',
'Orientation': 'orientation',
'Perimeter': 'perimeter',
'CroftonPerimeter': 'perimeter_crofton',
# 'PixelIdxList',
# 'PixelList',
'Slice': 'slice',
'Solidity': 'solidity',
# 'SubarrayIdx'
'WeightedCentralMoments': 'weighted_moments_central',
'WeightedCentroid': 'weighted_centroid',
'WeightedHuMoments': 'weighted_moments_hu',
'WeightedLocalCentroid': 'weighted_local_centroid',
'WeightedMoments': 'weighted_moments',
'WeightedNormalizedMoments': 'weighted_moments_normalized'
}
OBJECT_COLUMNS = {
'image', 'coords', 'convex_image', 'slice',
'filled_image', 'intensity_image'
}
COL_DTYPES = {
'area': int,
'bbox': int,
'bbox_area': int,
'moments_central': float,
'centroid': float,
'convex_area': int,
'convex_image': object,
'coords': object,
'eccentricity': float,
'equivalent_diameter': float,
'euler_number': int,
'extent': float,
'feret_diameter_max': float,
'filled_area': int,
'filled_image': object,
'moments_hu': float,
'image': object,
'inertia_tensor': float,
'inertia_tensor_eigvals': float,
'intensity_image': object,
'label': int,
'local_centroid': float,
'major_axis_length': float,
'max_intensity': int,
'mean_intensity': float,
'min_intensity': int,
'minor_axis_length': float,
'moments': float,
'moments_normalized': float,
'orientation': float,
'perimeter': float,
'perimeter_crofton': float,
'slice': object,
'solidity': float,
'weighted_moments_central': float,
'weighted_centroid': float,
'weighted_moments_hu': float,
'weighted_local_centroid': float,
'weighted_moments': float,
'weighted_moments_normalized': float
}
PROP_VALS = set(PROPS.values())
def _infer_number_of_required_args(func):
"""Infer the number of required arguments for a function
Parameters
----------
func : callable
The function that is being inspected.
Returns
-------
n_args : int
The number of required arguments of func.
"""
argspec = inspect.getfullargspec(func)
n_args = len(argspec.args)
if argspec.defaults is not None:
n_args -= len(argspec.defaults)
return n_args
def _infer_regionprop_dtype(func, *, intensity, ndim):
"""Infer the dtype of a region property calculated by func.
If a region property function always returns the same shape and type of
output regardless of input size, then the dtype is the dtype of the
returned array. Otherwise, the property has object dtype.
Parameters
----------
func : callable
Function to be tested. The signature should be array[bool] -> Any if
intensity is False, or *(array[bool], array[float]) -> Any otherwise.
intensity : bool
Whether the regionprop is calculated on an intensity image.
ndim : int
The number of dimensions for which to check func.
Returns
-------
dtype : NumPy data type
The data type of the returned property.
"""
labels = [1, 2]
sample = np.zeros((3,) * ndim, dtype=np.intp)
sample[(0,) * ndim] = labels[0]
sample[(slice(1, None),) * ndim] = labels[1]
propmasks = [(sample == n) for n in labels]
if intensity and _infer_number_of_required_args(func) == 2:
def _func(mask):
return func(mask, np.random.random(sample.shape))
else:
_func = func
props1, props2 = map(_func, propmasks)
if (np.isscalar(props1) and np.isscalar(props2)
or np.array(props1).shape == np.array(props2).shape):
dtype = np.array(props1).dtype.type
else:
dtype = np.object_
return dtype
def _cached(f):
@wraps(f)
def wrapper(obj):
cache = obj._cache
prop = f.__name__
if not ((prop in cache) and obj._cache_active):
cache[prop] = f(obj)
return cache[prop]
return wrapper
def only2d(method):
@wraps(method)
def func2d(self, *args, **kwargs):
if self._ndim > 2:
raise NotImplementedError('Property %s is not implemented for '
'3D images' % method.__name__)
return method(self, *args, **kwargs)
return func2d
class RegionProperties:
"""Please refer to `skimage.measure.regionprops` for more information
on the available region properties.
"""
def __init__(self, slice, label, label_image, intensity_image,
cache_active, *, extra_properties=None):
if intensity_image is not None:
ndim = label_image.ndim
if not (
intensity_image.shape[:ndim] == label_image.shape
and intensity_image.ndim in [ndim, ndim + 1]
):
raise ValueError('Label and intensity image shapes must match,'
' except for channel (last) axis.')
multichannel = label_image.shape < intensity_image.shape
else:
multichannel = False
self.label = label
self._slice = slice
self.slice = slice
self._label_image = label_image
self._intensity_image = intensity_image
self._cache_active = cache_active
self._cache = {}
self._ndim = label_image.ndim
self._multichannel = multichannel
self._spatial_axes = tuple(range(self._ndim))
self._extra_properties = {}
if extra_properties is None:
extra_properties = []
for func in extra_properties:
name = func.__name__
if hasattr(self, name):
msg = (
f"Extra property '{name}' is shadowed by existing "
"property and will be inaccessible. Consider renaming it."
)
warn(msg)
self._extra_properties = {
func.__name__: func for func in extra_properties
}
def __getattr__(self, attr):
if attr in self._extra_properties:
func = self._extra_properties[attr]
n_args = _infer_number_of_required_args(func)
# determine whether func requires intensity image
if n_args == 2:
if self._intensity_image is not None:
return func(self.image, self.intensity_image)
else:
raise AttributeError(
f"intensity image required to calculate {attr}"
)
elif n_args == 1:
return func(self.image)
else:
raise AttributeError(
"Custom regionprop function's number of arguments must be 1 or 2"
f"but {attr} takes {n_args} arguments."
)
else:
raise AttributeError(
f"'{type(self)}' object has no attribute '{attr}'"
)
@property
@_cached
def area(self):
return np.sum(self.image)
@property
def bbox(self):
"""
Returns
-------
A tuple of the bounding box's start coordinates for each dimension,
followed by the end coordinates for each dimension
"""
return tuple([self.slice[i].start for i in range(self._ndim)] +
[self.slice[i].stop for i in range(self._ndim)])
@property
def bbox_area(self):
return self.image.size
@property
def centroid(self):
return tuple(self.coords.mean(axis=0))
@property
@_cached
def convex_area(self):
return np.sum(self.convex_image)
@property
@_cached
def convex_image(self):
from ..morphology.convex_hull import convex_hull_image
return convex_hull_image(self.image)
@property
def coords(self):
indices = np.nonzero(self.image)
return np.vstack([indices[i] + self.slice[i].start
for i in range(self._ndim)]).T
@property
@only2d
def eccentricity(self):
l1, l2 = self.inertia_tensor_eigvals
if l1 == 0:
return 0
return sqrt(1 - l2 / l1)
@property
def equivalent_diameter(self):
return (2 * self._ndim * self.area / PI) ** (1 / self._ndim)
@property
def euler_number(self):
if self._ndim not in [2, 3]:
raise NotImplementedError('Euler number is implemented for '
'2D or 3D images only')
return euler_number(self.image, self._ndim)
@property
def extent(self):
return self.area / self.image.size
@property
def feret_diameter_max(self):
identity_convex_hull = np.pad(self.convex_image,
2, mode='constant', constant_values=0)
if self._ndim == 2:
coordinates = np.vstack(find_contours(identity_convex_hull, .5,
fully_connected='high'))
elif self._ndim == 3:
coordinates, _, _, _ = marching_cubes(identity_convex_hull, level=.5)
distances = pdist(coordinates, 'sqeuclidean')
return sqrt(np.max(distances))
@property
def filled_area(self):
return np.sum(self.filled_image)
@property
@_cached
def filled_image(self):
structure = np.ones((3,) * self._ndim)
return ndi.binary_fill_holes(self.image, structure)
@property
@_cached
def image(self):
return self._label_image[self.slice] == self.label
@property
@_cached
def inertia_tensor(self):
mu = self.moments_central
return _moments.inertia_tensor(self.image, mu)
@property
@_cached
def inertia_tensor_eigvals(self):
return _moments.inertia_tensor_eigvals(self.image,
T=self.inertia_tensor)
@property
@_cached
def intensity_image(self):
if self._intensity_image is None:
raise AttributeError('No intensity image specified.')
image = (
self.image
if not self._multichannel
else np.expand_dims(self.image, self._ndim)
)
return self._intensity_image[self.slice] * image
def _intensity_image_double(self):
return self.intensity_image.astype(np.double)
@property
def local_centroid(self):
M = self.moments
return tuple(M[tuple(np.eye(self._ndim, dtype=int))] /
M[(0,) * self._ndim])
@property
def max_intensity(self):
return np.max(self.intensity_image[self.image], axis=0)
@property
def mean_intensity(self):
return np.mean(self.intensity_image[self.image], axis=0)
@property
def min_intensity(self):
return np.min(self.intensity_image[self.image], axis=0)
@property
def major_axis_length(self):
l1 = self.inertia_tensor_eigvals[0]
return 4 * sqrt(l1)
@property
def minor_axis_length(self):
l2 = self.inertia_tensor_eigvals[-1]
return 4 * sqrt(l2)
@property
@_cached
def moments(self):
M = _moments.moments(self.image.astype(np.uint8), 3)
return M
@property
@_cached
def moments_central(self):
mu = _moments.moments_central(self.image.astype(np.uint8),
self.local_centroid, order=3)
return mu
@property
@only2d
def moments_hu(self):
return _moments.moments_hu(self.moments_normalized)
@property
@_cached
def moments_normalized(self):
return _moments.moments_normalized(self.moments_central, 3)
@property
@only2d
def orientation(self):
a, b, b, c = self.inertia_tensor.flat
if a - c == 0:
if b < 0:
return -PI / 4.
else:
return PI / 4.
else:
return 0.5 * atan2(-2 * b, c - a)
@property
@only2d
def perimeter(self):
return perimeter(self.image, 4)
@property
@only2d
def perimeter_crofton(self):
return perimeter_crofton(self.image, 4)
@property
def solidity(self):
return self.area / self.convex_area
@property
def weighted_centroid(self):
ctr = self.weighted_local_centroid
return tuple(idx + slc.start
for idx, slc in zip(ctr, self.slice))
@property
def weighted_local_centroid(self):
M = self.weighted_moments
return (M[tuple(np.eye(self._ndim, dtype=int))] /
M[(0,) * self._ndim])
@property
@_cached
def weighted_moments(self):
image = self._intensity_image_double()
if self._multichannel:
moments = np.stack(
[_moments.moments(image[..., i], order=3)
for i in range(image.shape[-1])],
axis=-1,
)
else:
moments = _moments.moments(image, order=3)
return moments
@property
@_cached
def weighted_moments_central(self):
ctr = self.weighted_local_centroid
image = self._intensity_image_double()
if self._multichannel:
moments_list = [
_moments.moments_central(
image[..., i], center=ctr[..., i], order=3
)
for i in range(image.shape[-1])
]
moments = np.stack(moments_list, axis=-1)
else:
moments = _moments.moments_central(image, ctr, order=3)
return moments
@property
@only2d
def weighted_moments_hu(self):
nu = self.weighted_moments_normalized
if self._multichannel:
nchannels = self._intensity_image.shape[-1]
return np.stack(
[_moments.moments_hu(nu[..., i]) for i in range(nchannels)],
axis=-1,
)
else:
return _moments.moments_hu(nu)
@property
@_cached
def weighted_moments_normalized(self):
mu = self.weighted_moments_central
if self._multichannel:
nchannels = self._intensity_image.shape[-1]
return np.stack(
[_moments.moments_normalized(mu[..., i], order=3)
for i in range(nchannels)],
axis=-1,
)
else:
return _moments.moments_normalized(mu, order=3)
return _moments.moments_normalized(self.weighted_moments_central, 3)
def __iter__(self):
props = PROP_VALS
if self._intensity_image is None:
unavailable_props = ('intensity_image',
'max_intensity',
'mean_intensity',
'min_intensity',
'weighted_moments',
'weighted_moments_central',
'weighted_centroid',
'weighted_local_centroid',
'weighted_moments_hu',
'weighted_moments_normalized')
props = props.difference(unavailable_props)
return iter(sorted(props))
def __getitem__(self, key):
value = getattr(self, key, None)
if value is not None:
return value
else: # backwards compatibility
return getattr(self, PROPS[key])
def __eq__(self, other):
if not isinstance(other, RegionProperties):
return False
for key in PROP_VALS:
try:
# so that NaNs are equal
np.testing.assert_equal(getattr(self, key, None),
getattr(other, key, None))
except AssertionError:
return False
return True
# For compatibility with code written prior to 0.16
_RegionProperties = RegionProperties
def _props_to_dict(regions, properties=('label', 'bbox'), separator='-'):
"""Convert image region properties list into a column dictionary.
Parameters
----------
regions : (N,) list
List of RegionProperties objects as returned by :func:`regionprops`.
properties : tuple or list of str, optional
Properties that will be included in the resulting dictionary
For a list of available properties, please see :func:`regionprops`.
Users should remember to add "label" to keep track of region
identities.
separator : str, optional
For non-scalar properties not listed in OBJECT_COLUMNS, each element
will appear in its own column, with the index of that element separated
from the property name by this separator. For example, the inertia
tensor of a 2D region will appear in four columns:
``inertia_tensor-0-0``, ``inertia_tensor-0-1``, ``inertia_tensor-1-0``,
and ``inertia_tensor-1-1`` (where the separator is ``-``).
Object columns are those that cannot be split in this way because the
number of columns would change depending on the object. For example,
``image`` and ``coords``.
Returns
-------
out_dict : dict
Dictionary mapping property names to an array of values of that
property, one value per region. This dictionary can be used as input to
pandas ``DataFrame`` to map property names to columns in the frame and
regions to rows.
Notes
-----
Each column contains either a scalar property, an object property, or an
element in a multidimensional array.
Properties with scalar values for each region, such as "eccentricity", will
appear as a float or int array with that property name as key.
Multidimensional properties *of fixed size* for a given image dimension,
such as "centroid" (every centroid will have three elements in a 3D image,
no matter the region size), will be split into that many columns, with the
name {property_name}{separator}{element_num} (for 1D properties),
{property_name}{separator}{elem_num0}{separator}{elem_num1} (for 2D
properties), and so on.
For multidimensional properties that don't have a fixed size, such as
"image" (the image of a region varies in size depending on the region
size), an object array will be used, with the corresponding property name
as the key.
Examples
--------
>>> from skimage import data, util, measure
>>> image = data.coins()
>>> label_image = measure.label(image > 110, connectivity=image.ndim)
>>> proplist = regionprops(label_image, image)
>>> props = _props_to_dict(proplist, properties=['label', 'inertia_tensor',
... 'inertia_tensor_eigvals'])
>>> props # doctest: +ELLIPSIS +SKIP
{'label': array([ 1, 2, ...]), ...
'inertia_tensor-0-0': array([ 4.012...e+03, 8.51..., ...]), ...
...,
'inertia_tensor_eigvals-1': array([ 2.67...e+02, 2.83..., ...])}
The resulting dictionary can be directly passed to pandas, if installed, to
obtain a clean DataFrame:
>>> import pandas as pd # doctest: +SKIP
>>> data = pd.DataFrame(props) # doctest: +SKIP
>>> data.head() # doctest: +SKIP
label inertia_tensor-0-0 ... inertia_tensor_eigvals-1
0 1 4012.909888 ... 267.065503
1 2 8.514739 ... 2.834806
2 3 0.666667 ... 0.000000
3 4 0.000000 ... 0.000000
4 5 0.222222 ... 0.111111
"""
out = {}
n = len(regions)
for prop in properties:
r = regions[0]
rp = getattr(r, prop)
if prop in COL_DTYPES:
dtype = COL_DTYPES[prop]
else:
func = r._extra_properties[prop]
dtype = _infer_regionprop_dtype(
func,
intensity=r._intensity_image is not None,
ndim=r.image.ndim,
)
column_buffer = np.zeros(n, dtype=dtype)
# scalars and objects are dedicated one column per prop
# array properties are raveled into multiple columns
# for more info, refer to notes 1
if np.isscalar(rp) or prop in OBJECT_COLUMNS or dtype is np.object_:
for i in range(n):
column_buffer[i] = regions[i][prop]
out[prop] = np.copy(column_buffer)
else:
if isinstance(rp, np.ndarray):
shape = rp.shape
else:
shape = (len(rp),)
for ind in np.ndindex(shape):
for k in range(n):
loc = ind if len(ind) > 1 else ind[0]
column_buffer[k] = regions[k][prop][loc]
modified_prop = separator.join(map(str, (prop,) + ind))
out[modified_prop] = np.copy(column_buffer)
return out
def regionprops_table(label_image, intensity_image=None,
properties=('label', 'bbox'),
*,
cache=True, separator='-', extra_properties=None):
"""Compute image properties and return them as a pandas-compatible table.
The table is a dictionary mapping column names to value arrays. See Notes
section below for details.
.. versionadded:: 0.16
Parameters
----------
label_image : (N, M[, P]) ndarray
Labeled input image. Labels with value 0 are ignored.
intensity_image : (M, N[, P][, C]) ndarray, optional
Intensity (i.e., input) image with same size as labeled image, plus
optionally an extra dimension for multichannel data.
Default is None.
.. versionchanged:: 0.18.0
The ability to provide an extra dimension for channels was added.
properties : tuple or list of str, optional
Properties that will be included in the resulting dictionary
For a list of available properties, please see :func:`regionprops`.
Users should remember to add "label" to keep track of region
identities.
cache : bool, optional
Determine whether to cache calculated properties. The computation is
much faster for cached properties, whereas the memory consumption
increases.
separator : str, optional
For non-scalar properties not listed in OBJECT_COLUMNS, each element
will appear in its own column, with the index of that element separated
from the property name by this separator. For example, the inertia
tensor of a 2D region will appear in four columns:
``inertia_tensor-0-0``, ``inertia_tensor-0-1``, ``inertia_tensor-1-0``,
and ``inertia_tensor-1-1`` (where the separator is ``-``).
Object columns are those that cannot be split in this way because the
number of columns would change depending on the object. For example,
``image`` and ``coords``.
extra_properties : Iterable of callables
Add extra property computation functions that are not included with
skimage. The name of the property is derived from the function name,
the dtype is inferred by calling the function on a small sample.
If the name of an extra property clashes with the name of an existing
property the extra property wil not be visible and a UserWarning is
issued. A property computation function must take a region mask as its
first argument. If the property requires an intensity image, it must
accept the intensity image as the second argument.
Returns
-------
out_dict : dict
Dictionary mapping property names to an array of values of that
property, one value per region. This dictionary can be used as input to
pandas ``DataFrame`` to map property names to columns in the frame and
regions to rows. If the image has no regions,
the arrays will have length 0, but the correct type.
Notes
-----
Each column contains either a scalar property, an object property, or an
element in a multidimensional array.
Properties with scalar values for each region, such as "eccentricity", will
appear as a float or int array with that property name as key.
Multidimensional properties *of fixed size* for a given image dimension,
such as "centroid" (every centroid will have three elements in a 3D image,
no matter the region size), will be split into that many columns, with the
name {property_name}{separator}{element_num} (for 1D properties),
{property_name}{separator}{elem_num0}{separator}{elem_num1} (for 2D
properties), and so on.
For multidimensional properties that don't have a fixed size, such as
"image" (the image of a region varies in size depending on the region
size), an object array will be used, with the corresponding property name
as the key.
Examples
--------
>>> from skimage import data, util, measure
>>> image = data.coins()
>>> label_image = measure.label(image > 110, connectivity=image.ndim)
>>> props = measure.regionprops_table(label_image, image,
... properties=['label', 'inertia_tensor',
... 'inertia_tensor_eigvals'])
>>> props # doctest: +ELLIPSIS +SKIP
{'label': array([ 1, 2, ...]), ...
'inertia_tensor-0-0': array([ 4.012...e+03, 8.51..., ...]), ...
...,
'inertia_tensor_eigvals-1': array([ 2.67...e+02, 2.83..., ...])}
The resulting dictionary can be directly passed to pandas, if installed, to
obtain a clean DataFrame:
>>> import pandas as pd # doctest: +SKIP
>>> data = pd.DataFrame(props) # doctest: +SKIP
>>> data.head() # doctest: +SKIP
label inertia_tensor-0-0 ... inertia_tensor_eigvals-1
0 1 4012.909888 ... 267.065503
1 2 8.514739 ... 2.834806
2 3 0.666667 ... 0.000000
3 4 0.000000 ... 0.000000
4 5 0.222222 ... 0.111111
[5 rows x 7 columns]
If we want to measure a feature that does not come as a built-in
property, we can define custom functions and pass them as
``extra_properties``. For example, we can create a custom function
that measures the intensity quartiles in a region:
>>> from skimage import data, util, measure
>>> import numpy as np
>>> def quartiles(regionmask, intensity):
... return np.percentile(intensity[regionmask], q=(25, 50, 75))
>>>
>>> image = data.coins()
>>> label_image = measure.label(image > 110, connectivity=image.ndim)
>>> props = measure.regionprops_table(label_image, intensity_image=image,
... properties=('label',),
... extra_properties=(quartiles,))
>>> import pandas as pd # doctest: +SKIP
>>> pd.DataFrame(props).head() # doctest: +SKIP
label quartiles-0 quartiles-1 quartiles-2
0 1 117.00 123.0 130.0
1 2 111.25 112.0 114.0
2 3 111.00 111.0 111.0
3 4 111.00 111.5 112.5
4 5 112.50 113.0 114.0
"""
regions = regionprops(label_image, intensity_image=intensity_image,
cache=cache, extra_properties=extra_properties)
if extra_properties is not None:
properties = (
list(properties) + [prop.__name__ for prop in extra_properties]
)
if len(regions) == 0:
ndim = label_image.ndim
label_image = np.zeros((3,) * ndim, dtype=int)
label_image[(1,) * ndim] = 1
if intensity_image is not None:
intensity_image = np.zeros(
label_image.shape + intensity_image.shape[ndim:],
dtype=intensity_image.dtype
)
regions = regionprops(label_image, intensity_image=intensity_image,
cache=cache, extra_properties=extra_properties)
out_d = _props_to_dict(regions, properties=properties,
separator=separator)
return {k: v[:0] for k, v in out_d.items()}
return _props_to_dict(
regions, properties=properties, separator=separator
)
def regionprops(label_image, intensity_image=None, cache=True,
coordinates=None, *, extra_properties=None):
r"""Measure properties of labeled image regions.
Parameters
----------
label_image : (M, N[, P]) ndarray
Labeled input image. Labels with value 0 are ignored.
.. versionchanged:: 0.14.1
Previously, ``label_image`` was processed by ``numpy.squeeze`` and
so any number of singleton dimensions was allowed. This resulted in
inconsistent handling of images with singleton dimensions. To
recover the old behaviour, use
``regionprops(np.squeeze(label_image), ...)``.
intensity_image : (M, N[, P][, C]) ndarray, optional
Intensity (i.e., input) image with same size as labeled image, plus
optionally an extra dimension for multichannel data.
Default is None.
.. versionchanged:: 0.18.0
The ability to provide an extra dimension for channels was added.
cache : bool, optional
Determine whether to cache calculated properties. The computation is
much faster for cached properties, whereas the memory consumption
increases.
coordinates : DEPRECATED
This argument is deprecated and will be removed in a future version
of scikit-image.
See :ref:`Coordinate conventions <numpy-images-coordinate-conventions>`
for more details.
.. deprecated:: 0.16.0
Use "rc" coordinates everywhere. It may be sufficient to call
``numpy.transpose`` on your label image to get the same values as
0.15 and earlier. However, for some properties, the transformation
will be less trivial. For example, the new orientation is
:math:`\frac{\pi}{2}` plus the old orientation.
extra_properties : Iterable of callables
Add extra property computation functions that are not included with
skimage. The name of the property is derived from the function name,
the dtype is inferred by calling the function on a small sample.
If the name of an extra property clashes with the name of an existing
property the extra property wil not be visible and a UserWarning is
issued. A property computation function must take a region mask as its
first argument. If the property requires an intensity image, it must
accept the intensity image as the second argument.
Returns
-------
properties : list of RegionProperties
Each item describes one labeled region, and can be accessed using the
attributes listed below.
Notes
-----
The following properties can be accessed as attributes or keys:
**area** : int
Number of pixels of the region.
**bbox** : tuple
Bounding box ``(min_row, min_col, max_row, max_col)``.
Pixels belonging to the bounding box are in the half-open interval
``[min_row; max_row)`` and ``[min_col; max_col)``.
**bbox_area** : int
Number of pixels of bounding box.
**centroid** : array
Centroid coordinate tuple ``(row, col)``.
**convex_area** : int
Number of pixels of convex hull image, which is the smallest convex
polygon that encloses the region.
**convex_image** : (H, J) ndarray
Binary convex hull image which has the same size as bounding box.
**coords** : (N, 2) ndarray
Coordinate list ``(row, col)`` of the region.
**eccentricity** : float
Eccentricity of the ellipse that has the same second-moments as the
region. The eccentricity is the ratio of the focal distance
(distance between focal points) over the major axis length.
The value is in the interval [0, 1).
When it is 0, the ellipse becomes a circle.
**equivalent_diameter** : float
The diameter of a circle with the same area as the region.
**euler_number** : int
Euler characteristic of the set of non-zero pixels.
Computed as number of connected components subtracted by number of
holes (input.ndim connectivity). In 3D, number of connected
components plus number of holes subtracted by number of tunnels.
**extent** : float
Ratio of pixels in the region to pixels in the total bounding box.
Computed as ``area / (rows * cols)``
**feret_diameter_max** : float
Maximum Feret's diameter computed as the longest distance between
points around a region's convex hull contour as determined by
``find_contours``. [5]_
**filled_area** : int
Number of pixels of the region will all the holes filled in. Describes
the area of the filled_image.
**filled_image** : (H, J) ndarray
Binary region image with filled holes which has the same size as
bounding box.
**image** : (H, J) ndarray
Sliced binary region image which has the same size as bounding box.
**inertia_tensor** : ndarray
Inertia tensor of the region for the rotation around its mass.
**inertia_tensor_eigvals** : tuple
The eigenvalues of the inertia tensor in decreasing order.
**intensity_image** : ndarray
Image inside region bounding box.
**label** : int
The label in the labeled input image.
**local_centroid** : array
Centroid coordinate tuple ``(row, col)``, relative to region bounding
box.
**major_axis_length** : float
The length of the major axis of the ellipse that has the same
normalized second central moments as the region.
**max_intensity** : float
Value with the greatest intensity in the region.
**mean_intensity** : float
Value with the mean intensity in the region.
**min_intensity** : float
Value with the least intensity in the region.
**minor_axis_length** : float
The length of the minor axis of the ellipse that has the same
normalized second central moments as the region.
**moments** : (3, 3) ndarray
Spatial moments up to 3rd order::
m_ij = sum{ array(row, col) * row^i * col^j }
where the sum is over the `row`, `col` coordinates of the region.
**moments_central** : (3, 3) ndarray
Central moments (translation invariant) up to 3rd order::
mu_ij = sum{ array(row, col) * (row - row_c)^i * (col - col_c)^j }
where the sum is over the `row`, `col` coordinates of the region,
and `row_c` and `col_c` are the coordinates of the region's centroid.
**moments_hu** : tuple
Hu moments (translation, scale and rotation invariant).
**moments_normalized** : (3, 3) ndarray
Normalized moments (translation and scale invariant) up to 3rd order::
nu_ij = mu_ij / m_00^[(i+j)/2 + 1]
where `m_00` is the zeroth spatial moment.
**orientation** : float
Angle between the 0th axis (rows) and the major
axis of the ellipse that has the same second moments as the region,
ranging from `-pi/2` to `pi/2` counter-clockwise.
**perimeter** : float
Perimeter of object which approximates the contour as a line
through the centers of border pixels using a 4-connectivity.
**perimeter_crofton** : float
Perimeter of object approximated by the Crofton formula in 4
directions.
**slice** : tuple of slices
A slice to extract the object from the source image.
**solidity** : float
Ratio of pixels in the region to pixels of the convex hull image.
**weighted_centroid** : array
Centroid coordinate tuple ``(row, col)`` weighted with intensity
image.
**weighted_local_centroid** : array
Centroid coordinate tuple ``(row, col)``, relative to region bounding
box, weighted with intensity image.
**weighted_moments** : (3, 3) ndarray
Spatial moments of intensity image up to 3rd order::
wm_ij = sum{ array(row, col) * row^i * col^j }
where the sum is over the `row`, `col` coordinates of the region.
**weighted_moments_central** : (3, 3) ndarray
Central moments (translation invariant) of intensity image up to
3rd order::
wmu_ij = sum{ array(row, col) * (row - row_c)^i * (col - col_c)^j }
where the sum is over the `row`, `col` coordinates of the region,
and `row_c` and `col_c` are the coordinates of the region's weighted
centroid.
**weighted_moments_hu** : tuple
Hu moments (translation, scale and rotation invariant) of intensity
image.
**weighted_moments_normalized** : (3, 3) ndarray
Normalized moments (translation and scale invariant) of intensity
image up to 3rd order::
wnu_ij = wmu_ij / wm_00^[(i+j)/2 + 1]
where ``wm_00`` is the zeroth spatial moment (intensity-weighted area).
Each region also supports iteration, so that you can do::
for prop in region:
print(prop, region[prop])
See Also
--------
label
References
----------
.. [1] Wilhelm Burger, Mark Burge. Principles of Digital Image Processing:
Core Algorithms. Springer-Verlag, London, 2009.
.. [2] B. Jähne. Digital Image Processing. Springer-Verlag,
Berlin-Heidelberg, 6. edition, 2005.
.. [3] T. H. Reiss. Recognizing Planar Objects Using Invariant Image
Features, from Lecture notes in computer science, p. 676. Springer,
Berlin, 1993.
.. [4] https://en.wikipedia.org/wiki/Image_moment
.. [5] W. Pabst, E. Gregorová. Characterization of particles and particle
systems, pp. 27-28. ICT Prague, 2007.
https://old.vscht.cz/sil/keramika/Characterization_of_particles/CPPS%20_English%20version_.pdf
Examples
--------
>>> from skimage import data, util
>>> from skimage.measure import label, regionprops
>>> img = util.img_as_ubyte(data.coins()) > 110
>>> label_img = label(img, connectivity=img.ndim)
>>> props = regionprops(label_img)
>>> # centroid of first labeled object
>>> props[0].centroid
(22.72987986048314, 81.91228523446583)
>>> # centroid of first labeled object
>>> props[0]['centroid']
(22.72987986048314, 81.91228523446583)
Add custom measurements by passing functions as ``extra_properties``
>>> from skimage import data, util
>>> from skimage.measure import label, regionprops
>>> import numpy as np
>>> img = util.img_as_ubyte(data.coins()) > 110
>>> label_img = label(img, connectivity=img.ndim)
>>> def pixelcount(regionmask):
... return np.sum(regionmask)
>>> props = regionprops(label_img, extra_properties=(pixelcount,))
>>> props[0].pixelcount
7741
>>> props[1]['pixelcount']
42
"""
if label_image.ndim not in (2, 3):
raise TypeError('Only 2-D and 3-D images supported.')
if not np.issubdtype(label_image.dtype, np.integer):
if np.issubdtype(label_image.dtype, bool):
raise TypeError(
'Non-integer image types are ambiguous: '
'use skimage.measure.label to label the connected'
'components of label_image,'
'or label_image.astype(np.uint8) to interpret'
'the True values as a single label.')
else:
raise TypeError(
'Non-integer label_image types are ambiguous')
if coordinates is not None:
if coordinates == 'rc':
msg = ('The coordinates keyword argument to skimage.measure.'
'regionprops is deprecated. All features are now computed '
'in rc (row-column) coordinates. Please remove '
'`coordinates="rc"` from all calls to regionprops before '
'updating scikit-image.')
warn(msg, stacklevel=2, category=FutureWarning)
else:
msg = ('Values other than "rc" for the "coordinates" argument '
'to skimage.measure.regionprops are no longer supported. '
'You should update your code to use "rc" coordinates and '
'stop using the "coordinates" argument, or use skimage '
'version 0.15.x or earlier.')
raise ValueError(msg)
regions = []
objects = ndi.find_objects(label_image)
for i, sl in enumerate(objects):
if sl is None:
continue
label = i + 1
props = RegionProperties(sl, label, label_image, intensity_image,
cache, extra_properties=extra_properties)
regions.append(props)
return regions
def _parse_docs():
import re
import textwrap
doc = regionprops.__doc__ or ''
matches = re.finditer(r'\*\*(\w+)\*\* \:.*?\n(.*?)(?=\n [\*\S]+)',
doc, flags=re.DOTALL)
prop_doc = {m.group(1): textwrap.dedent(m.group(2)) for m in matches}
return prop_doc
def _install_properties_docs():
prop_doc = _parse_docs()
for p in [member for member in dir(RegionProperties)
if not member.startswith('_')]:
getattr(RegionProperties, p).__doc__ = prop_doc[p]
if __debug__:
# don't install docstrings when in optimized/non-debug mode
_install_properties_docs()