def plot_calibrated_data(self, data_to_plot, *args, **kwargs):
""" Plot calibrated data for visual inspection.
Parameters
----------
data_to_plot : string
Specify the calibrated data to be plotted. Valid options are:
{'au_x_grating_dp', 'au_x_grating_im', 'moo3_dp', 'moo3_im'}
"""
# Construct object containing user defined data to plot and set the
# calibration checking that it is defined.
if data_to_plot == 'au_x_grating_dp':
dpeg = self.calibration_data.au_x_grating_dp
size = dpeg.data.shape[0]
dpegs = stack_method([dpeg, dpeg, dpeg, dpeg])
dpegs = ElectronDiffraction(dpegs.data.reshape((2, 2, size, size)))
dpegs.apply_affine_transformation(self.affine_matrix,
preserve_range=True,
inplace=True)
data = dpegs.mean((0, 1))
data.set_diffraction_calibration(self.diffraction_calibration)
elif data_to_plot == 'au_x_grating_im':
data = self.calibration_data.au_x_grating_im
#Plot the data
data.plot(*args, **kwargs)
def get_distortion_residuals(self, mask_radius, spread):
"""Obtain residuals for experimental data and distortion corrected data
with respect to a simulated symmetric ring pattern.
Parameters
----------
mask_radius : int
Radius, in pixels, for a mask over the direct beam disc.
spread : float
Gaussian spread of each ring in the simulated pattern.
Returns
-------
diff_init : ElectronDiffraction
Difference between experimental data and simulated symmetric ring
pattern.
diff_end : ElectronDiffraction
Difference between distortion corrected data and simulated symmetric
ring pattern.
"""
# Check all required parameters are defined as attributes
if self.calibration_data.au_x_grating_dp is None:
raise ValueError(
"This method requires an Au X-grating diffraction "
"pattern to be provided. Please update the "
"CalibrationDataLibrary.")
if self.affine_matrix is None:
raise ValueError(
"This method requires a distortion matrix to have "
"been determined. Use get_elliptical_distortion "
"to determine this matrix.")
# Set name for experimental data pattern
dpeg = self.calibration_data.au_x_grating_dp
ringP = self.ring_params
size = dpeg.data.shape[0]
dpref = generate_ring_pattern(image_size=size,
mask=True,
mask_radius=mask_radius,
scale=ringP[0],
amplitude=ringP[1],
spread=spread,
direct_beam_amplitude=ringP[3],
asymmetry=1,
rotation=ringP[5])
# Apply distortion corrections to experimental data
dpegs = stack_method([dpeg, dpeg, dpeg, dpeg])
dpegs = ElectronDiffraction(dpegs.data.reshape((2, 2, size, size)))
dpegs.apply_affine_transformation(self.affine_matrix,
preserve_range=True,
inplace=True)
# Calculate residuals to be returned
diff_init = ElectronDiffraction(dpeg.data - dpref.data)
diff_end = ElectronDiffraction(dpegs.inav[0, 0].data - dpref.data)
residuals = stack_method([diff_init, diff_end])
return ElectronDiffraction(residuals)
def plot_corrected_diffraction_pattern(self, reference_circle=True):
"""Plot the distortion corrected diffraction pattern with an optional
reference circle.
Parameters
----------
reference_circle : bool
If True a CircleROI widget is added to the plot for reference.
"""
# Check all required parameters are defined as attributes
if self.calibration_data.au_x_grating_dp is None:
raise ValueError(
"This method requires an Au X-grating diffraction "
"pattern to be provided. Please update the "
"CalibrationDataLibrary.")
if self.affine_matrix is None:
raise ValueError(
"This method requires a distortion matrix to have "
"been determined. Use get_elliptical_distortion "
"to determine this matrix.")
# Set name for experimental data pattern
dpeg = self.calibration_data.au_x_grating_dp
# Apply distortion corrections to experimental data
size = dpeg.data.shape[0]
dpegs = stack_method([dpeg, dpeg, dpeg, dpeg])
dpegs = ElectronDiffraction(dpegs.data.reshape((2, 2, size, size)))
dpegs.apply_affine_transformation(self.affine_matrix,
preserve_range=True,
inplace=True)
dpegm = dpegs.mean((0, 1))
# Plot distortion corrected data
dpegm.plot(cmap='magma', vmax=0.1)
# add reference circle if specified
if reference_circle is True:
circ = CircleROI(cx=128, cy=128, r=53.5, r_inner=0)
circ.add_widget(dpegm)
def get_diffraction_calibration(self, mask_length, linewidth):
"""Determine the diffraction pattern pixel size calibration in units of
reciprocal Angsstroms per pixel.
Parameters
----------
mask_length : float
Halfwidth of the region excluded from peak finding around the
diffraction pattern center.
linewidth : float
Width of Line2DROI used to obtain line trace from distortion
corrected diffraction pattern.
Returns
-------
diff_cal : float
Diffraction calibration in reciprocal Angstroms per pixel.
"""
# Check that necessary calibration data is provided
if self.calibration_data.au_x_grating_dp is None:
raise ValueError(
"This method requires an Au X-grating diffraction "
"pattern to be provided. Please update the "
"CalibrationDataLibrary.")
if self.affine_matrix is None:
raise ValueError(
"This method requires a distortion matrix to have "
"been determined. Use get_elliptical_distortion "
"to determine this matrix.")
dpeg = self.calibration_data.au_x_grating_dp
size = dpeg.data.shape[0]
dpegs = stack_method([dpeg, dpeg, dpeg, dpeg])
dpegs = ElectronDiffraction(dpegs.data.reshape((2, 2, size, size)))
dpegs.apply_affine_transformation(self.affine_matrix,
preserve_range=True,
inplace=True)
dpegm = dpegs.mean((0, 1))
# Define line roi along which to take trace for calibration
line = Line2DROI(x1=5, y1=5, x2=250, y2=250, linewidth=linewidth)
# Obtain line trace
trace = line(dpegm)
trace = trace.as_signal1D(0)
# Find peaks in line trace either side of direct beam
db = (np.sqrt(2) * 128) - (5 * np.sqrt(2))
pka = trace.isig[db +
mask_length:].find_peaks1D_ohaver()[0]['position']
pkb = trace.isig[:db -
mask_length].find_peaks1D_ohaver()[0]['position']
# Determine predicted position of 022 peak of Au pattern d022=1.437
au_pre = db - (self.ring_params[0] / 1.437)
au_post = db + (self.ring_params[0] / 1.437)
# Calculate differences between predicted and measured positions
prediff = np.abs(pkb - au_pre)
postdiff = np.abs(pka - au_post)
# Calculate new calibration value based on most accurate peak positions
dc = (2 / 1.437) / (pka[postdiff == min(postdiff)] -
pkb[prediff == min(prediff)])
# Store diffraction calibration value as attribute
self.diffraction_calibration = dc[0]
return dc[0]