def _compute_output_grid(convolvable1, convolvable2):
"""Calculate the output grid to be used when two convolvables are on different grids."""
# determine output spacing
errorstr = 'when convolving two analytic objects, one must have a grid.'
if m.isnan(convolvable1.sample_spacing):
if m.isnan(convolvable2.sample_spacing):
raise ValueError(errorstr)
else:
output_spacing = convolvable2.sample_spacing
elif m.isnan(convolvable2.sample_spacing):
if m.isnan(convolvable1.sample_spacing):
raise ValueError(errorstr)
else:
output_spacing = convolvable1.sample_spacing
else:
output_spacing = min(convolvable1.sample_spacing,
convolvable2.sample_spacing)
# determine region of output
if convolvable1.unit_x is None:
c1ux, c1uy = (0, 0), (0, 0)
else:
c1ux, c1uy = convolvable1.unit_x, convolvable1.unit_y
if convolvable2.unit_x is None: # this isn't totally DRY
c2ux, c2uy = (0, 0), (0, 0)
else:
c2ux, c2uy = convolvable2.unit_x, convolvable2.unit_y
output_x_left = min(c1ux[0], c2ux[0])
output_x_right = max(c1ux[-1], c2ux[-1])
output_y_left = min(c1uy[0], c2uy[0])
output_y_right = max(c1uy[-1], c2uy[-1])
# if region is not an integer multiple of sample spacings, enlarge to make this true
x_rem = (output_x_right - output_x_left) % output_spacing
y_rem = (output_y_right - output_y_left) % output_spacing
if x_rem > 1e-3:
adj = x_rem / 2
output_x_left -= adj
output_x_right += adj
if y_rem > 1e-3:
adj = y_rem / 2
output_y_left -= adj
output_y_right += adj
# finally, compute the output window
samples_x = int((output_x_right - output_x_left) // output_spacing)
samples_y = int((output_y_right - output_y_left) // output_spacing)
unit_out_x = m.linspace(output_x_left, output_x_right, samples_x)
unit_out_y = m.linspace(output_y_left, output_y_right, samples_y)
return unit_out_x, unit_out_y
def _encircled_energy_core(mtf_data, radius, nu_p, dx, dy):
"""Core computation of encircled energy, based on Baliga 1988.
Parameters
----------
mtf_data : `numpy.ndarray`
unaliased MTF data
radius : `float`
radius of "detector"
nu_p : `numpy.ndarray`
radial spatial frequencies
dx : `float`
x frequency delta
dy : `float`
y frequency delta
Returns
-------
`float`
encircled energy for given radius
"""
integration_fourier = m.j1(2 * m.pi * radius * nu_p) / nu_p
# division by nu_p will cause a NaN at the origin, 0.5 is the
# analytical value of jinc there
integration_fourier[m.isnan(integration_fourier)] = 0.5
dat = mtf_data * integration_fourier
return radius * dat.sum() * dx * dy
def fcn(self):
"""Complex wavefunction associated with the pupil."""
phase = self.change_phase_unit(to='waves', inplace=False)
fcn = m.exp(1j * 2 * m.pi *
phase) # phase implicitly in units of waves, no 2pi/l
# guard against nans in phase
fcn[m.isnan(phase)] = 0
if self.mask_target in ('fcn', 'both'):
fcn *= self._mask
return fcn
def _phase_to_wavefunction(self):
"""Compute the wavefunction from the phase.
Returns
-------
`Pupil`
this pupil instance
"""
phase = self.change_phase_unit(to='waves', inplace=False)
self.fcn = m.exp(1j * 2 * m.pi *
phase) # phase implicitly in units of waves, no 2pi/l
# guard against nans in phase
self.fcn[m.isnan(phase)] = 0
return self
def fill(self, _with=0):
"""Fill invalid (NaN) values.
Parameters
----------
_with : `float`, optional
value to fill with
Returns
-------
`Interferogram`
self
"""
nans = m.isnan(self.phase)
self.phase[nans] = _with
return self
def dropout_percentage(self):
"""Percentage of pixels in the data that are invalid (NaN)."""
return m.count_nonzero(m.isnan(self.phase)) / self.phase.size * 100
def __init__(self,
samples=128,
dia=1.0,
wavelength=0.55,
opd_unit='waves',
mask='circle',
mask_target='both',
ux=None,
uy=None,
phase=None):
"""Create a new `Pupil` instance.
Parameters
----------
samples : `int`, optional
number of samples across the pupil interior
dia : `float`, optional
diameter of the pupil, mm
wavelength : `float`, optional
wavelength of light, um
opd_unit : `str`, optional, {'waves', 'um', 'nm'}
unit used to m.express the OPD. Equivalent strings may be used to the
valid options, e.g. 'microns', or 'nanometers'
mask : `str` or `numpy.ndarray`
mask used to define the amplitude and boundary of the pupil; any
regular polygon from `prysm.geometry` as a string, e.g. 'circle' is
valid. A user-provided ndarray can also be used.
mask_target : `str`, {'phase', 'fcn', 'both', None}
which array to mask during pupil creation; only masking fcn is
faster for numerical propagations but will make plot2d() and the
phase array not be truncated properly. Note that if the mask is not
binary and `phase` or `both` is used, phase plots will also not be
correct, as they will be attenuated by the mask.
ux : `np.ndarray`
x axis units
uy : `np.ndarray`
y axis units
phase : `np.ndarray`
phase data
Notes
-----
If ux give, assume uy and phase also given; skip much of the pupil building process
and simply copy values.
Raises
------
ValueError
if the OPD unit given is invalid
"""
if ux is None:
# must build a pupil
self.dia = dia
ux = m.linspace(-dia / 2, dia / 2, samples)
uy = m.linspace(-dia / 2, dia / 2, samples)
self.samples = samples
need_to_build = True
else:
# data already known
need_to_build = False
super().__init__(unit_x=ux,
unit_y=uy,
phase=phase,
wavelength=wavelength,
phase_unit=opd_unit,
spatial_unit='mm')
self.xaxis_label = 'Pupil ξ'
self.yaxis_label = 'Pupil η'
self.zaxis_label = 'OPD'
self.rho = self.phi = None
if need_to_build:
if type(mask) is not m.ndarray:
mask = mcache(mask, self.samples)
self._mask = mask
self.mask_target = mask_target
self.build()
self.mask(self._mask, self.mask_target)
else:
protomask = m.isnan(phase)
mask = m.ones(protomask.shape)
mask[protomask] = 0
self._mask = mask
self.mask_target = 'fcn'
def write_zygo_ascii(file,
phase,
unit_x,
unit_y,
wavelength=0.6328,
intensity=None,
high_phase_res=False):
# construct the header
timestamp = datetime.datetime.now()
line1 = 'Zygo ASCII Data File - Format 2'
line2 = '0 0 0 0 ' + timestamp.strftime('"%a %b %d %H:%M:%S %Y').ljust(
30, ' ') + '"'
if intensity is None:
line3 = '0 0 0 0 0 0'
else:
raise NotImplementedError(
'writing of ASCII files with nonempty intensity not yet supported.'
)
px, py = phase.shape
ox = m.searchsorted(unit_x, 0)
oy = m.searchsorted(unit_y, 0)
line4 = f'{oy} {ox} {py} {px}'
line5 = '"' + ' ' * 81 + '"'
line6 = '"' + ' ' * 39 + '"'
line7 = '"' + ' ' * 39 + '"'
timestamp_int = int(str(timestamp.timestamp()).split('.')[0])
res = (unit_x[1] - unit_x[0]) * 1e-3 # mm to m
line8 = f'0 0.5 {wavelength*1e-6} 0 1 0 {res} {timestamp_int}' # end is timestamp in integer seconds
line9 = f'{py} {px} 0 0 0 0 ' + '"' + ' ' * 9 + '"'
line10 = '0 0 0 0 0 0 0 0 0 0'
line11 = f'{int(high_phase_res)} 1 20 2 0 0 0 0 0'
line12 = '0 ' + '"' + ' ' * 12 + '"'
line13 = '1 0'
line14 = '"' + ' ' * 7 + '"'
header_lines = (line1, line2, line3, line4, line5, line6, line7, line8,
line9, line10, line11, line12, line13, line14)
header = '\n'.join(header_lines) + '\n'
if intensity is None:
line15 = '#'
line16 = '#'
# process the phase and write out
coef = ZYGO_PHASE_RES_FACTORS[int(high_phase_res)]
encoded_phase = phase * (coef / wavelength / wavelength / 0.5)
encoded_phase[m.isnan(encoded_phase)] = ZYGO_INVALID_PHASE
encoded_phase = m.flipud(encoded_phase.astype(m.int64))
encoded_phase = encoded_phase.flatten()
npts = encoded_phase.shape[0]
fits_by_ten = npts // 10
boundary = 10 * fits_by_ten
# create an in-memory buffer and write out the phase to it
s = StringIO()
s.write(header)
s.write('#\n#\n')
m.savetxt(s,
encoded_phase[:boundary].reshape(-1, 10),
fmt='%d',
delimiter=' ',
newline=' \n')
tail = ' '.join((str(d) for d in encoded_phase[boundary:]))
s.write(tail)
s.write('\n#\n')
s.seek(0)
if not isinstance(file, IOBase):
with open(file, 'w') as fd:
shutil.copyfileobj(s, fd)
else:
shutil.copyfileobj(s, fd)
