def main():
# Variables to be set.
wavelength = 0.5 * pow(10, -6)
pixeltom = 6 * pow(10, -6)
distance = 0.2
propagation_type = 'IR Fresnel'
k = wavenumber(wavelength)
sample_field = np.zeros((500, 500), dtype=np.complex64)
sample_field[240:260, 240:260] = 1000
random_phase = np.pi * np.random.random(sample_field.shape)
sample_field = sample_field * np.cos(
random_phase) + 1j * sample_field * np.sin(random_phase)
sample_field = torch.from_numpy(sample_field)
hologram = propagate_beam_torch(sample_field, k, distance, pixeltom,
wavelength, propagation_type)
reconstruction = propagate_beam_torch(hologram, k, -distance, pixeltom,
wavelength, propagation_type)
# from odak.visualize.plotly import detectorshow
# detector = detectorshow()
# detector.add_field(sample_field)
# detector.show()
# detector.add_field(hologram)
# detector.show()
# detector.add_field(reconstruction)
# detector.show()
assert True == True
def main():
# Variables to be set.
wavelength = 0.5 * pow(10, -6)
pixeltom = 6 * pow(10, -6)
distance = 0.1
propagation_type = 'Fraunhofer'
k = wavenumber(wavelength)
sample_field = np.zeros((150, 150), dtype=np.complex64)
sample_field[40:60, 40:60] = 10
sample_field = add_random_phase(sample_field)
hologram = propagate_beam(sample_field, k, distance, pixeltom, wavelength,
propagation_type)
if propagation_type == 'Fraunhofer':
distance = np.abs(distance)
reconstruction = propagate_beam(hologram, k, distance, pixeltom,
wavelength, 'Fraunhofer Inverse')
from odak.visualize.plotly import detectorshow
detector = detectorshow()
detector.add_field(sample_field)
detector.show()
detector.add_field(hologram)
detector.show()
detector.add_field(reconstruction / np.amax(np.abs(reconstruction)))
detector.show()
assert True == True
def test():
no0 = [100, 100]
no1 = [100, 100]
size0 = [10., 10.]
size1 = [10., 10.]
wavelength = 0.005
surface_location_0 = [0., 0., 0.]
surface_location_1 = [0., 0., 10.]
wave_number = wave.wavenumber(wavelength)
samples_surface_0 = tools.grid_sample(no=no0,
size=size0,
center=surface_location_0)
samples_surface_1 = tools.grid_sample(no=no1,
size=size1,
center=surface_location_1)
field_0 = np.zeros((no0[0], no0[1]))
field_0[50, 50] = 1.
field_0[0, 20] = 2.
field_0 = field_0.reshape((no0[0] * no0[1]))
# Propagates to a specific plane.
field_1 = wave.propagate_field(samples_surface_0,
samples_surface_1,
field_0,
wave_number,
direction=1)
# Reconstruction: propagates back from that specific plane to start plane.
field_2 = wave.propagate_field(samples_surface_1,
samples_surface_0,
field_1,
wave_number,
direction=-1)
assert True == True
def compare():
wavelength = 0.5 * pow(10, -6)
pixeltom = 6 * pow(10, -6)
distance = 0.2
propagation_type = 'IR Fresnel'
k = wavenumber(wavelength)
sample_field = np.zeros((500, 500), dtype=np.complex64)
sample_field[240:260, 240:260] = 1000
random_phase = np.pi * np.random.random(sample_field.shape)
sample_field = sample_field * np.cos(
random_phase) + 1j * sample_field * np.sin(random_phase)
sample_field_torch = torch.from_numpy(sample_field)
## Propagate and reconstruct using torch.
hologram_torch = propagate_beam_torch(sample_field_torch, k, distance,
pixeltom, wavelength,
propagation_type)
reconstruction_torch = propagate_beam_torch(hologram_torch, k, -distance,
pixeltom, wavelength,
propagation_type)
## Propagate and reconstruct using np.
hologram = propagate_beam(sample_field, k, distance, pixeltom, wavelength,
propagation_type)
reconstruction = propagate_beam(hologram, k, -distance, pixeltom,
wavelength, propagation_type)
np.testing.assert_array_almost_equal(hologram_torch.numpy(), hologram, 3)
def main():
# Variables to be set.
wavelength = 0.5*pow(10,-6)
pixeltom = 6*pow(10,-6)
distance = 0.2
propagation_type = 'Bandlimited Angular Spectrum'
k = wavenumber(wavelength)
sample_field = np.zeros((500,500),dtype=np.complex64)
sample_field[
240:260,
240:260
] = 1000
random_phase = np.pi*np.random.random(sample_field.shape)
sample_field = sample_field*np.cos(random_phase)+1j*sample_field*np.sin(random_phase)
criterion = torch.nn.MSELoss()
if np.__name__ == 'cupy':
sample_field = np.asnumpy(sample_field)
sample_field = torch.from_numpy(sample_field)
hologram = propagate_beam_torch(
sample_field,
k,
distance,
pixeltom,
wavelength,
propagation_type
)
hologram.requires_grad = True
reconstruction = propagate_beam_torch(
hologram,
k,
-distance,
pixeltom,
wavelength,
propagation_type
)
loss = criterion(torch.abs(sample_field), torch.abs(reconstruction))
loss.backward()
print(hologram.grad)
print('backward successfully')
#from odak.visualize.plotly import detectorshow
#detector = detectorshow()
#detector.add_field(sample_field)
#detector.show()
#detector.add_field(hologram)
#detector.show()
#detector.add_field(reconstruction)
#detector.show()
assert True==True
def main():
# Variables to be set.
wavelength = 0.5*pow(10,-6)
pixeltom = 6*pow(10,-6)
distance = 10.0
propagation_type = 'Fraunhofer'
k = wavenumber(wavelength)
sample_field = np.zeros((150,150),dtype=np.complex64)
sample_field = np.zeros((150,150),dtype=np.complex64)
sample_field[
65:85,
65:85
] = 1
sample_field = add_random_phase(sample_field)
hologram = propagate_beam(
sample_field,
k,
distance,
pixeltom,
wavelength,
propagation_type
)
if propagation_type == 'Fraunhofer':
# Uncomment if you want to match the physical size of hologram and input field.
#from odak.wave import fraunhofer_equal_size_adjust
#hologram = fraunhofer_equal_size_adjust(hologram,distance,pixeltom,wavelength)
propagation_type = 'Fraunhofer Inverse'
distance = np.abs(distance)
reconstruction = propagate_beam(
hologram,
k,
-distance,
pixeltom,
wavelength,
propagation_type
)
#from odak.visualize.plotly import detectorshow
#detector = detectorshow()
#detector.add_field(sample_field)
#detector.show()
#detector = detectorshow()
#detector.add_field(hologram)
#detector.show()
#detector = detectorshow()
#detector.add_field(reconstruction)
#detector.show()
assert True==True
def __init__(self,
phase=None,
shape=[10., 10.],
center=[0., 0., 0.],
angles=[0., 0., 0.],
diffusion_angle=5.,
diffusion_no=[3, 3],
name='diffuser'):
"""
Class to represent a simple thin diffuser with a random phase.
Parameters
----------
phase : ndarray
Initial phase to be loaded. If non provided, it will start with a random phase.
shape : list
Shape of the detector.
center : list
Center of the detector.
angles : list
Rotation angles of the detector in degrees.
diffusion angles : list
Full angle of diffusion along two axes.
diffusion_no : list
Number of rays to be generated along two axes at each diffusion.
"""
self.settings = {
'name': name,
'center': center,
'angles': angles,
'rotation mode': 'XYZ',
'shape': shape,
'diffusion angle': diffusion_angle,
'number of diffusion rays': diffusion_no
}
self.plane = define_plane(self.settings['center'],
angles=self.settings['angles'])
self.k = wavenumber(0.05)
self.diffusion_points = circular_uniform_sample(
no=self.settings["number of diffusion rays"],
radius=np.tan(np.radians(self.settings["diffusion angle"] / 2.)),
center=[0., 0., 1.])
if type(phase) == type(None):
self.surface_points = grid_sample(no=[100, 100],
size=self.settings["shape"],
center=self.settings["center"],
angles=self.settings["angles"])
def gerchberg_saxton(field,
n_iterations,
distance,
dx,
wavelength,
slm_range=6.28,
propagation_type='IR Fresnel'):
"""
Definition to compute a hologram using an iterative method called Gerchberg-Saxton phase retrieval algorithm. For more on the method, see: Gerchberg, Ralph W. "A practical algorithm for the determination of phase from image and diffraction plane pictures." Optik 35 (1972): 237-246.
Parameters
----------
field : torch.cfloat
Complex field (MxN).
distance : float
Propagation distance.
dx : float
Size of one single pixel in the field grid (in meters).
wavelength : float
Wavelength of the electric field.
slm_range : float
Typically this is equal to two pi. See odak.wave.adjust_phase_only_slm_range() for more.
propagation_type : str
Type of the propagation (IR Fresnel, TR Fresnel, Fraunhofer).
Result
---------
hologram : torch.cfloat
Calculated complex hologram.
reconstruction : torch.cfloat
Calculated reconstruction using calculated hologram.
"""
k = wavenumber(wavelength)
reconstruction = field
for i in range(n_iterations):
hologram = propagate_beam(reconstruction, k, -distance, dx, wavelength,
propagation_type)
hologram = produce_phase_only_slm_pattern(hologram, slm_range)
reconstruction = propagate_beam(hologram, k, distance, dx, wavelength,
propagation_type)
reconstruction = set_amplitude(hologram, field)
reconstruction = propagate_beam(hologram, k, distance, dx, wavelength,
propagation_type)
return hologram, reconstruction
def main():
# Variables to be set.
wavelength = 0.5 * pow(10, -6)
pixeltom = 6 * pow(10, -6)
distance = 10.0
propagation_type = 'Fraunhofer'
k = wavenumber(wavelength)
sample_field = np.random.rand(150, 150).astype(np.complex64)
plane_field = plane_tilt(sample_field.shape[0],
sample_field.shape[1], [0.3, 0.9, 1., 1.],
dx=pixeltom,
axis='x')
lens_field = quadratic_phase_function(sample_field.shape[0],
sample_field.shape[1],
k,
focal=0.3,
dx=pixeltom)
prism_field = prism_phase_function(sample_field.shape[0],
sample_field.shape[1],
k,
angle=0.1,
dx=pixeltom,
axis='x')
sample_field = sample_field * plane_field
#from odak.visualize.plotly import detectorshow
#detector = detectorshow()
#detector.add_field(sample_field)
#detector.show()
#detector = detectorshow()
#detector.add_field(hologram)
#detector.show()
#detector = detectorshow()
#detector.add_field(reconstruction)
#detector.show()
assert True == True
