def __init__(self,
stddev_maj,
stddev_min,
position_angle,
support_scaling=8,
**kwargs):
self._model = Gaussian2D(1. / (2 * np.pi * stddev_maj * stddev_min),
0,
0,
x_stddev=stddev_maj,
y_stddev=stddev_min,
theta=position_angle)
try:
from astropy.modeling.utils import ellipse_extent
except ImportError:
raise NotImplementedError("EllipticalGaussian2DKernel requires"
" astropy 1.1b1 or greater.")
max_extent = \
np.max(ellipse_extent(stddev_maj, stddev_min, position_angle))
self._default_size = \
_round_up_to_odd_integer(support_scaling * 2 * max_extent)
super(EllipticalGaussian2DKernel, self).__init__(**kwargs)
self._truncation = np.abs(1. - 1 / self._array.sum())
def test_ellipse_extent():
# Test this properly bounds the ellipse
imshape = (100, 100)
coords = y, x = np.indices(imshape)
amplitude = 1
x0 = 50
y0 = 50
a = 30
b = 10
theta = np.pi / 4
model = Ellipse2D(amplitude, x0, y0, a, b, theta)
dx, dy = ellipse_extent(a, b, theta)
limits = ((y0 - dy, y0 + dy), (x0 - dx, x0 + dx))
model.bounding_box = limits
actual = model.render(coords=coords)
expected = model(x, y)
# Check that the full ellipse is captured
np.testing.assert_allclose(expected, actual, atol=0, rtol=1)
# Check the bounding_box isn't too large
limits = np.array(limits).flatten()
for i in [0, 1]:
s = actual.sum(axis=i)
diff = np.abs(limits[2 * i] - np.where(s > 0)[0][0])
assert diff < 1
def bounding_box(self):
"""
Tuple defining the default ``bounding_box`` limits.
``((y_low, y_high), (x_low, x_high))``
"""
a = self.a
b = self.b
theta = self.theta.value
dx, dy = ellipse_extent(a, b, theta)
return ((self.y_0 - dy, self.y_0 + dy),
(self.x_0 - dx, self.x_0 + dx))
def __init__(self, stddev_maj, stddev_min, position_angle, support_scaling=1,
**kwargs):
self._model = Ellipse2D(1. / (np.pi * stddev_maj * stddev_min), 0, 0,
stddev_maj, stddev_min, position_angle)
try:
from astropy.modeling.utils import ellipse_extent
except ImportError:
raise NotImplementedError("EllipticalTophat2DKernel requires"
" astropy 1.1b1 or greater.")
max_extent = \
np.max(ellipse_extent(stddev_maj, stddev_min, position_angle))
self._default_size = \
_round_up_to_odd_integer(support_scaling * 2 * max_extent)
super(EllipticalTophat2DKernel, self).__init__(**kwargs)
self._truncation = 0
def __init__(self, stddev_maj, stddev_min, position_angle,
support_scaling=8, **kwargs):
self._model = Gaussian2D(1. / (2 * np.pi * stddev_maj * stddev_min), 0,
0, x_stddev=stddev_maj, y_stddev=stddev_min,
theta=position_angle)
try:
from astropy.modeling.utils import ellipse_extent
except ImportError:
raise NotImplementedError("EllipticalGaussian2DKernel requires"
" astropy 1.1b1 or greater.")
max_extent = \
np.max(ellipse_extent(stddev_maj, stddev_min, position_angle))
self._default_size = \
_round_up_to_odd_integer(support_scaling * 2 * max_extent)
super(EllipticalGaussian2DKernel, self).__init__(**kwargs)
self._truncation = np.abs(1. - 1 / self._array.sum())
def __init__(self, stddev_maj, stddev_min, position_angle, support_scaling=1,
**kwargs):
self._model = Ellipse2D(1. / (np.pi * stddev_maj * stddev_min), 0, 0,
stddev_maj, stddev_min, position_angle)
try:
from astropy.modeling.utils import ellipse_extent
except ImportError:
raise NotImplementedError("EllipticalTophat2DKernel requires"
" astropy 1.1b1 or greater.")
max_extent = \
np.max(ellipse_extent(stddev_maj, stddev_min, position_angle))
self._default_size = \
_round_up_to_odd_integer(support_scaling * 2 * max_extent)
super(EllipticalTophat2DKernel, self).__init__(**kwargs)
self._truncation = 0
def bounding_box(self, factor=5.5):
"""
Tuple defining the default ``bounding_box`` limits in each dimension,
``((y_low, y_high), (x_low, x_high))``
The default offset from the mean is 5.5-sigma, corresponding
to a relative error < 1e-7. The limits are adjusted for rotation.
Parameters
----------
factor : float, optional
The multiple of `x_stddev` and `y_stddev` used to define the limits.
The default is 5.5.
Examples
--------
>>> from astropy.modeling.models import Gaussian2D
>>> model = Gaussian2D(x_mean=0, y_mean=0, x_stddev=1, y_stddev=2)
>>> model.bounding_box
((-11.0, 11.0), (-5.5, 5.5))
This range can be set directly (see: `Model.bounding_box
<astropy.modeling.Model.bounding_box>`) or by using a different factor
like:
>>> model.bounding_box = model.bounding_box(factor=2)
>>> model.bounding_box
((-4.0, 4.0), (-2.0, 2.0))
"""
a = factor * self.x_stddev
b = factor * self.y_stddev
theta = self.theta.value
dx, dy = ellipse_extent(a, b, theta)
return ((self.y_mean - dy, self.y_mean + dy),
(self.x_mean - dx, self.x_mean + dx))
