def preprocessing(self):
""".. method:: preprocessing()
Collects together all the preprocessing functions that are required to begin phase retrieval.
"""
# Get the scan positions
self.positions = CXData(name='positions', data=[])
self.ptycho_mesh()
if CXP.measurement.simulate_data:
self.simulate_data()
else:
# Read in raw data
self.det_mod = CXData(name = 'det_mod')
if CXP.actions.preprocess_data:
self.det_mod.read_in_data()
else:
self.det_mod.load()
if CXP.io.whitefield_filename:
self.probe_det_mod = CXData(name='probe_det_mod')
self.probe_det_mod.preprocess_data()
self.object = CXData(name='object', data=[sp.zeros((self.ob_p, self.ob_p), complex)])
self.probe_intensity = CXData(name='probe_intensity', data=[sp.zeros((self.p, self.p))])
self.probe = CXModal(modes=[])
self.psi = CXModal(modes=[])
for i in range(CXP.reconstruction.probe_modes):
self.probe.modes.append(CXData(name='probe{:d}'.format(i), data=[sp.zeros((self.p, self.p), complex)]))
self.psi.modes.append(CXData(name='psi{:d}'.format(i), data=[sp.zeros((self.p, self.p), complex) for i in xrange(self.det_mod.len())]))
self.init_probe()
# Calculate STXM image if this is a ptycho scan
if len(self.det_mod.data) > 1:
self.calc_stxm_image()
if CXP.actions.process_dpc:
self.process_dpc()
def simulate_data(self):
CXP.log.info('Simulating diffraction patterns.')
self.sample = CXData()
self.sample.load(CXP.io.simulation_sample_filename[0])
self.sample.data[0] = self.sample.data[0].astype(float)
self.sample.normalise(val=0.8)
self.sample.data[0]+=0.2
self.input_probe = CXModal()
if len(CXP.io.simulation_sample_filename)>1:
ph = CXData()
ph.load(CXP.io.simulation_sample_filename[1])
ph.data[0] = ph.data[0].astype(float)
ph.normalise(val=np.pi/3)
self.sample.data[0] = self.sample.data[0]*exp(complex(0., 1.)*ph.data[0])
p = self.sample.data[0].shape[0]
ham_window = sp.hamming(p)[:,np.newaxis]*sp.hamming(p)[np.newaxis,:]
sample_large = CXData(data=sp.zeros((CXP.ob_p, CXP.ob_p), complex))
sample_large.data[0][CXP.ob_p/2-p/2:CXP.ob_p/2+p/2, CXP.ob_p/2-p/2:CXP.ob_p/2+p/2] = self.sample.data[0]*ham_window
ker = sp.arange(0, p)
fwhm = p/3.0
radker = sp.hypot(*sp.ogrid[-p/2:p/2,-p/2:p/2])
gaussian = exp(-1.0*(fwhm/2.35)**-2. * radker**2.0 )
ortho_modes = lambda n1, n2 : gaussian*np.sin(n1*math.pi*ker/p)[:,np.newaxis]*np.sin(n2*math.pi*ker/p)[np.newaxis, :]
mode_generator = lambda : sp.floor(4*sp.random.random(2))+1
used_modes = []
self.input_psi = CXModal()
for mode in range(CXP.reconstruction.probe_modes):
if mode==0:
new_mode = [1,1]
else:
new_mode = list(mode_generator())
while new_mode in used_modes:
new_mode = list(mode_generator())
used_modes.append(new_mode)
CXP.log.info('Simulating mode {:d}: [{:d}, {:d}]'.format(mode, int(new_mode[0]), int(new_mode[1])))
ph_func = gauss_smooth(np.random.random((p,p)), 10)
self.input_probe.modes.append(CXData(name='probe{:d}'.format(mode),
data=ortho_modes(new_mode[0], new_mode[1])*exp(complex(0.,np.pi)*ph_func/ph_func.max())))
self.input_probe.normalise()
self.input_probe.orthogonalise()
for mode in range(CXP.reconstruction.probe_modes):
p2 = p/2
x, y = self.positions.correct
self.input_psi.modes.append(CXData(name='input_psi_mode{:d}'.format(mode), data=[]))
for i in xrange(len(x)):
if i%(len(x)/10)==0.:
CXP.log.info('Simulating diff patt {:d}'.format(i))
tmp = (CXData.shift(sample_large, -1.0*(x[i]-CXP.ob_p/2), -1.0*(y[i]-CXP.ob_p/2))
[CXP.ob_p/2-p2:CXP.ob_p/2+p2, CXP.ob_p/2-p2:CXP.ob_p/2+p2]*
self.input_probe[mode][0])
self.input_psi[mode].data.append(tmp.data[0])
# Add modes incoherently
self.det_mod = CXModal.modal_sum(abs(fft2(self.input_psi)))
self.det_mod.save(path=CXP.io.base_dir+'/'+CXP.io.scan_id+'/raw_data/{:s}.npy'.format('det_mod'))
