def test_nonuniformscale2d_update_from_vector():
scale = np.array([3, 4])
h**o = np.array([[scale[0], 0, 0],
[0, scale[1], 0],
[0, 0, 1]])
tr = NonUniformScale(np.array([1, 2]))
tr.from_vector_inplace(scale)
assert_equal(tr.h_matrix, h**o)
def test_nonuniformscale2d_from_vector():
scale = np.array([1, 2])
h**o = np.array([[scale[0], 0, 0],
[0, scale[1], 0],
[0, 0, 1]])
tr = NonUniformScale.identity(2).from_vector(scale)
assert_equal(tr.h_matrix, h**o)
def glyph(self, vectors_block_size=10, use_negative=False, channels=None):
r"""
Create glyph of a feature image. If feature_data has negative values,
the use_negative flag controls whether there will be created a glyph of
both positive and negative values concatenated the one on top of the
other.
Parameters
----------
vectors_block_size: int
Defines the size of each block with vectors of the glyph image.
use_negative: bool
Defines whether to take into account possible negative values of
feature_data.
"""
# first, choose the appropriate channels
if channels is None:
pixels = self.pixels[..., :4]
elif channels != 'all':
pixels = self.pixels[..., channels]
else:
pixels = self.pixels
# compute the glyph
negative_weights = -pixels
scale = np.maximum(pixels.max(), negative_weights.max())
pos = _create_feature_glyph(pixels, vectors_block_size)
pos = pos * 255 / scale
glyph_image = pos
if use_negative and pixels.min() < 0:
neg = _create_feature_glyph(negative_weights, vectors_block_size)
neg = neg * 255 / scale
glyph_image = np.concatenate((pos, neg))
glyph = Image(glyph_image)
# correct landmarks
from menpo.transform.affine import NonUniformScale
image_shape = np.array(self.shape, dtype=np.double)
glyph_shape = np.array(glyph.shape, dtype=np.double)
nus = NonUniformScale(glyph_shape / image_shape)
glyph.landmarks = self.landmarks
nus.apply_inplace(glyph.landmarks)
return glyph
def test_nonuniformscale_identity_3d():
assert_allclose(NonUniformScale.identity(3).h_matrix, np.eye(4))
def rescale(self, scale, interpolator='scipy', round='ceil', **kwargs):
r"""
Return a copy of this image, rescaled by a given factor.
All image information (landmarks) are rescaled appropriately.
Parameters
----------
scale : float or tuple
The scale factor. If a tuple, the scale to apply to each dimension.
If a single float, the scale will be applied uniformly across
each dimension.
interpolator : 'scipy' or 'c', optional
The interpolator that should be used to perform the warp.
Default: 'scipy'
round: {'ceil', 'floor', 'round'}
Rounding function to be applied to floating point shapes.
Default: 'ceil'
kwargs : dict
Passed through to the interpolator. See `menpo.interpolation`
for details.
Returns
-------
rescaled_image : type(self)
A copy of this image, rescaled.
Raises
------
ValueError:
If less scales than dimensions are provided.
If any scale is less than or equal to 0.
"""
# Pythonic way of converting to list if we are passed a single float
try:
if len(scale) < self.n_dims:
raise ValueError(
'Must provide a scale per dimension.'
'{} scales were provided, {} were expected.'.format(
len(scale), self.n_dims
)
)
except TypeError: # Thrown when len() is called on a float
scale = [scale] * self.n_dims
# Make sure we have a numpy array
scale = np.asarray(scale)
for s in scale:
if s <= 0:
raise ValueError('Scales must be positive floats.')
transform = NonUniformScale(scale)
from menpo.image.boolean import BooleanImage
# use the scale factor to make the template mask bigger
template_mask = BooleanImage.blank(transform.apply(self.shape),
round=round)
# due to image indexing, we can't just apply the pseduoinverse
# transform to achieve the scaling we want though!
# Consider a 3x rescale on a 2x4 image. Looking at each dimension:
# H 2 -> 6 so [0-1] -> [0-5] = 5/1 = 5x
# W 4 -> 12 [0-3] -> [0-11] = 11/3 = 3.67x
# => need to make the correct scale per dimension!
shape = np.array(self.shape, dtype=np.float)
# scale factors = max_index_after / current_max_index
# (note that max_index = length - 1, as 0 based)
scale_factors = (scale * shape - 1) / (shape - 1)
inverse_transform = NonUniformScale(scale_factors).pseudoinverse
# Note here we pass warp_mask to warp_to. In the case of
# Images that aren't MaskedImages this kwarg will
# harmlessly fall through so we are fine.
return self.warp_to(template_mask, inverse_transform,
warp_landmarks=True,
interpolator=interpolator, **kwargs)