def lbp(image, radius, points, ignore_zeros=False):
'''
features = lbp(image, radius, points, ignore_zeros=False)
Compute Linear Binary Patterns
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros (default: False)
Returns
-------
features : 1-D numpy ndarray
histogram of features
Reference
---------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. LECTURE NOTES IN COMPUTER SCIENCE (Springer)
2000, ISSU 1842, pages 404-420
'''
from ..interpolate import shift
from mahotas.features import _lbp
if ignore_zeros:
Y,X = np.nonzero(image)
def select(im):
return im[Y,X].ravel()
pixels = image[Y,X].ravel()
else:
select = np.ravel
pixels = image.ravel()
image = image.astype(np.float64)
angles = np.linspace(0, 2*np.pi, points+1)[:-1]
data = []
for dy,dx in zip(np.sin(angles), np.cos(angles)):
data.append(
select(shift(image, [radius*dy,radius*dx], order=1)))
data = np.array(data)
codes = (data > pixels).astype(np.int32)
codes *= (2**np.arange(points)[:,np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
final = fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.concatenate((compressed, [0]*(npivots - len(compressed))))
return compressed
def lbp_names(radius, points):
'''Return list of names (string) for LBP features
Parameters
----------
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
Returns
-------
names : list of str
See Also
--------
lbp : function
Compute LBP features
'''
from mahotas.features import _lbp
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
return ['lbp_r{}_p{}_{}'.format(radius, points, i) for i in range(npivots)]
def lbp_names(radius, points):
'''Return list of names (string) for LBP features
Parameters
----------
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
Returns
-------
names : list of str
See Also
--------
lbp : function
Compute LBP features
'''
from mahotas.features import _lbp
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
return ['lbp_r{}_p{}_{}'.format(radius, points, i) for i in range(npivots)]
def lbp_transform_local(image, radius, points, ignore_zeros=False, preserve_shape=True):
if ignore_zeros and preserve_shape:
raise ValueError('mahotas.features.lbp_transform: *ignore_zeros* and *preserve_shape* cannot both be used together')
image = np.asanyarray(image, dtype=np.float64)
if image.ndim != 2:
raise ValueError('mahotas.features.lbp_transform: This function is only defined for two dimensional images')
if ignore_zeros:
Y,X = np.nonzero(image)
def select(im):
return im[Y,X].ravel()
else:
select = np.ravel
pixels = select(image)
angles = np.linspace(0, 2*np.pi, points+1)[:-1]
data = []
for dy,dx in zip(np.sin(angles), np.cos(angles)):
data.append(
select(shift(image, [radius*dy,radius*dx], order=1)))
data = np.array(data)
codes = (data > pixels).astype(np.int32)
codes *= (2**np.arange(points)[:,np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
if preserve_shape:
codes = codes.reshape(image.shape)
return codes
def take_hist(codes, points):
final = fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.append(compressed, np.zeros(npivots - len(compressed)))
return compressed
def lbp(image, radius, points, ignore_zeros=False):
'''
features = lbp(image, radius, points, ignore_zeros=False)
Compute Linear Binary Patterns
The return value is a **histogram** of feature counts, where position ``i``
corresponds to the number of pixels that had code ``i``. The codes are
compressed so that impossible codes are not used. Therefore, this is the
``i``th feature, not just the feature with binary code ``i``.
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros (default: False)
Returns
-------
features : 1-D numpy ndarray
histogram of features. See above for a caveat on the interpretation of
these.
Reference
---------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. Lecture Notes in Computer Science (Springer)
2000, ISSU 1842, pages 404-420
'''
from mahotas.features import _lbp
codes = lbp_transform(image,
radius,
points,
ignore_zeros=ignore_zeros,
preserve_shape=False)
final = fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.append(compressed, np.zeros(npivots - len(compressed)))
return compressed
def lbp(image, radius, points, ignore_zeros=False):
'''
features = lbp(image, radius, points, ignore_zeros=False)
Compute Linear Binary Patterns
The return value is a **histogram** of feature counts, where position ``i``
corresponds to the number of pixels that had code ``i``. The codes are
compressed so that impossible codes are not used. Therefore, this is the
``i``th feature, not just the feature with binary code ``i``.
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros (default: False)
Returns
-------
features : 1-D numpy ndarray
histogram of features. See above for a caveat on the interpretation of
these.
Reference
---------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. Lecture Notes in Computer Science (Springer)
2000, ISSU 1842, pages 404-420
'''
from mahotas.features import _lbp
codes = lbp_transform(image, radius, points, ignore_zeros=ignore_zeros, preserve_shape=False)
final = fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.append(compressed, np.zeros(npivots - len(compressed)))
return compressed
def lbp_transform(image, radius, points, ignore_zeros=False, preserve_shape=True):
'''
transformed = lbp(image, radius, points, ignore_zeros=False, preserve_shape=True)
Compute Linear Binary Pattern Transform
The return value are the transformed pixel values **histogram** of feature counts, where position ``i``
corresponds to the number of pixels that had code ``i``. The codes are
compressed so that impossible codes are not used. Therefore, this is the
``i``th feature, not just the feature with binary code ``i``.
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros. Note that if you set this to ``True``, you
will need to set ``preserve_shape`` to False. (default: False)
preserve_shape : boolean, optional
whether to return an array with the same shape as ``image``. (default:
True)
Returns
-------
features : 1-D numpy ndarray
histogram of features. See above for a caveat on the interpretation of
these.
Reference
---------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. Lecture Notes in Computer Science (Springer)
2000, ISSU 1842, pages 404-420
'''
from ..interpolate import shift
from mahotas.features import _lbp
if ignore_zeros and preserve_shape:
raise ValueError('mahotas.features.lbp_transform: *ignore_zeros* and *preserve_shape* cannot both be used together')
image = np.asanyarray(image, dtype=np.float64)
if ignore_zeros:
Y,X = np.nonzero(image)
def select(im):
return im[Y,X].ravel()
else:
select = np.ravel
pixels = select(image)
angles = np.linspace(0, 2*np.pi, points+1)[:-1]
data = []
for dy,dx in zip(np.sin(angles), np.cos(angles)):
data.append(
select(shift(image, [radius*dy,radius*dx], order=1)))
data = np.array(data)
codes = (data > pixels).astype(np.int32)
codes *= (2**np.arange(points)[:,np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
if preserve_shape:
codes = codes.reshape(image.shape)
return codes
def lbp_transform(image,
radius,
points,
ignore_zeros=False,
preserve_shape=True):
'''
transformed = lbp(image, radius, points, ignore_zeros=False, preserve_shape=True)
Compute Linear Binary Pattern Transform
The return value are the transformed pixel values **histogram** of feature counts, where position ``i``
corresponds to the number of pixels that had code ``i``. The codes are
compressed so that impossible codes are not used. Therefore, this is the
``i``th feature, not just the feature with binary code ``i``.
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros. Note that if you set this to ``True``, you
will need to set ``preserve_shape`` to False. (default: False)
preserve_shape : boolean, optional
whether to return an array with the same shape as ``image``. (default:
True)
Returns
-------
features : 1-D numpy ndarray
histogram of features. See above for a caveat on the interpretation of
these.
References
----------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. Lecture Notes in Computer Science (Springer)
2000, ISSU 1842, pages 404-420
'''
from ..interpolate import shift
from mahotas.features import _lbp
if ignore_zeros and preserve_shape:
raise ValueError(
'mahotas.features.lbp_transform: *ignore_zeros* and *preserve_shape* cannot both be used together'
)
image = np.asanyarray(image, dtype=np.float64)
if image.ndim != 2:
raise ValueError(
'mahotas.features.lbp_transform: This function is only defined for two dimensional images'
)
if ignore_zeros:
Y, X = np.nonzero(image)
def select(im):
return im[Y, X].ravel()
else:
select = np.ravel
pixels = select(image)
angles = np.linspace(0, 2 * np.pi, points + 1)[:-1]
data = []
for dy, dx in zip(np.sin(angles), np.cos(angles)):
data.append(select(shift(image, [radius * dy, radius * dx], order=1)))
data = np.array(data)
codes = (data > pixels).astype(np.int32)
codes *= (2**np.arange(points)[:, np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
if preserve_shape:
codes = codes.reshape(image.shape)
return codes
def lbp(image, radius, points, ignore_zeros=False):
'''
features = lbp(image, radius, points, ignore_zeros=False)
Compute Linear Binary Patterns
Parameters
----------
image : ndarray
input image (2-D numpy ndarray)
radius : number (integer or floating point)
radius (in pixels)
points : integer
nr of points to consider
ignore_zeros : boolean, optional
whether to ignore zeros (default: False)
Returns
-------
features : 1-D numpy ndarray
histogram of features
Reference
---------
Gray Scale and Rotation Invariant Texture Classification with Local Binary Patterns
Ojala, T. Pietikainen, M. Maenpaa, T. LECTURE NOTES IN COMPUTER SCIENCE (Springer)
2000, ISSU 1842, pages 404-420
'''
from ..interpolate import shift
from mahotas.features import _lbp
if ignore_zeros:
Y, X = np.nonzero(image)
def select(im):
return im[Y, X].ravel()
pixels = image[Y, X].ravel()
else:
select = np.ravel
pixels = image.ravel()
image = image.astype(np.float64)
angles = np.linspace(0, 2 * np.pi, points + 1)[:-1]
data = []
for dy, dx in zip(np.sin(angles), np.cos(angles)):
data.append(select(shift(image, [radius * dy, radius * dx], order=1)))
data = np.array(data)
codes = (data > pixels).astype(np.int32)
codes *= (2**np.arange(points)[:, np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
final = fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.concatenate(
(compressed, [0] * (npivots - len(compressed))))
return compressed
def test_map():
assert len(set(_lbp.map(np.arange(256, dtype=np.uint32), 8))) == 36
def test_map():
assert len(set(_lbp.map(np.arange(256,dtype=np.uint32), 8))) == 36
def lddp(image,
radius1,
radius2,
points,
ignore_zeros=False,
preserve_shape=True):
"""
Custom implementation of 2nd order local directional derivative pattern
Originally obtained from mahotas.features.lbp_transform function.
An inner and an outer radius with respect to a point, which is each image pixel are selected.
Then, a set of points are obtained by interpolation on these radii, according to the number defined by *points*
argument. Note that if, for example, 8 points are given, there are 8 points that are considered on the inner radius
defined by equal angles starting from the central point and each one of them. If these two points (the origin, or the
centre) and each point define a straight line, also 8 points on the same lines are considered for the outer radius.
For reference see :
Guo, Zhenhua, et al. "Local directional derivative pattern for rotation invariant texture classification."
Neural Computing and Applications 21.8 (2012): 1893-1904.
:param np.array image: numpy array input image
:param int radius1: inner radius (in pixels)
:param int radius2: outer radius (in pixels)
:param int points: number of points to consider. It should be given regarding the inner radius, as the second set of points will be aligned to the ones lying in the inner circle.
:return: lddp histogram
"""
from mahotas import interpolate
from mahotas.features import _lbp
from mahotas import histogram
if ignore_zeros and preserve_shape:
raise ValueError(
'mahotas.features.lbp_transform: *ignore_zeros* and *preserve_shape* cannot both be used together'
)
image = np.asanyarray(image, dtype=np.float64)
if image.ndim != 2:
raise ValueError(
'mahotas.features.lbp_transform: This function is only defined for two dimensional images'
)
if ignore_zeros:
Y, X = np.nonzero(image)
def select(im):
return im[Y, X].ravel()
else:
select = np.ravel
pixels = select(image)
angles = np.linspace(0, 2 * np.pi, points + 1)[:-1]
data1 = []
for dy, dx in zip(np.sin(angles), np.cos(angles)):
data1.append(
select(
interpolate.shift(image, [radius1 * dy, radius1 * dx],
order=1)))
data1 = np.array(data1)
data2 = []
for dy, dx in zip(np.sin(angles), np.cos(angles)):
data2.append(
select(
interpolate.shift(image, [radius2 * dy, radius2 * dx],
order=1)))
data2 = np.array(data2)
data = np.array(data2 + pixels - 2 * data1)
codes = (data >= 0).astype(np.int32)
codes *= (2**np.arange(points)[:, np.newaxis])
codes = codes.sum(0)
codes = _lbp.map(codes.astype(np.uint32), points)
if preserve_shape:
codes = codes.reshape(image.shape)
final = histogram.fullhistogram(codes.astype(np.uint32))
codes = np.arange(2**points, dtype=np.uint32)
iters = codes.copy()
codes = _lbp.map(codes.astype(np.uint32), points)
pivots = (codes == iters)
npivots = np.sum(pivots)
compressed = final[pivots[:len(final)]]
compressed = np.append(compressed, np.zeros(npivots - len(compressed)))
return compressed
