def create_random_linear_transform(image,
fixed_parameters,
transform_type='affine',
sd_affine=1.0):
transform = ants.create_ants_transform(
transform_type="AffineTransform",
precision='float',
dimension=image.dimension)
ants.set_ants_transform_fixed_parameters(transform, fixed_parameters)
identity_parameters = ants.get_ants_transform_parameters(transform)
random_epsilon = np.random.normal(loc=0,
scale=sd_affine,
size=len(identity_parameters))
if transform_type == 'translation':
random_epsilon[:(len(identity_parameters) - image.dimension)] = 0
random_parameters = identity_parameters + random_epsilon
random_matrix = np.reshape(
random_parameters[:(len(identity_parameters) - image.dimension)],
newshape=(image.dimension, image.dimension))
decomposition = polar_decomposition(random_matrix)
if transform_type == "rigid":
random_matrix = decomposition['Z']
elif transform_type == "affine":
random_matrix = decomposition['Xtilde']
elif transform_type == "scaleShear":
random_matrix = decomposition['P']
random_parameters[:(len(identity_parameters) - image.dimension)] = \
np.reshape(random_matrix, newshape=(len(identity_parameters) - image.dimension))
ants.set_ants_transform_parameters(transform, random_parameters)
return (transform)
def test_set_ants_transform_parameters(self):
for tx in self.txs:
ants.set_ants_transform_parameters(tx, tx.parameters**2)