def _build_graph(self, x_train, global_step, hm_reg_scale,
height_map_noise):
'''
Builds the graph for this model.
:param x_train (graph node): input image.
:param global_step: Global step variable (unused in this model)
:param hm_reg_scale: Regularization coefficient for laplace l1 regularizer of phaseplate
:param height_map_noise: Noise added to height map to account for manufacturing deficiencies
:return: graph node for output image
'''
input_img = x_train
with tf.device('/device:GPU:0'):
# Input field is a planar wave.
input_field = tf.ones((1, self.wave_res[0], self.wave_res[1],
len(self.wave_lengths)))
# Planar wave hits aperture: phase is shifted by phaseplate
field = optics.height_map_element(
input_field,
wave_lengths=self.wave_lengths,
height_map_regularizer=optics.laplace_l1_regularizer(
hm_reg_scale),
height_map_initializer=None,
height_tolerance=height_map_noise,
refractive_idcs=self.refractive_idcs,
name='height_map_optics')
field = optics.circular_aperture(field)
# Propagate field from aperture to sensor
field = optics.propagate_fresnel(
field,
distance=self.sensor_distance,
sampling_interval=self.sample_interval,
wave_lengths=self.wave_lengths)
# The psf is the intensities of the propagated field.
psfs = optics.get_intensities(field)
# Downsample psf to image resolution & normalize to sum to 1
psfs = optics.area_downsampling_tf(psfs, self.patch_size)
psfs = tf.div(psfs, tf.reduce_sum(psfs, axis=[1, 2],
keepdims=True))
optics.attach_summaries('PSF', psfs, image=True, log_image=True)
# Image formation: PSF is convolved with input image
psfs = tf.transpose(psfs, [1, 2, 0, 3])
output_image = optics.img_psf_conv(input_img, psfs)
output_image = tf.cast(output_image, tf.float32)
optics.attach_summaries('output_image',
output_image,
image=True,
log_image=False)
output_image += tf.random_uniform(minval=0.001,
maxval=0.02,
shape=[])
return output_image
def forward_model(input_field):
field = optics.height_map_element(
input_field,
wave_lengths=self.wave_lengths,
height_map_regularizer=optics.laplace_l1_regularizer(
hm_reg_scale),
height_map_initializer=None,
height_tolerance=height_map_noise,
refractive_idcs=self.refractive_idcs,
name='height_map_optics')
field = optics.circular_aperture(field)
field = optics.propagate_fresnel(
field,
distance=self.distance,
input_sample_interval=self.input_sample_interval,
wave_lengths=self.wave_lengths)
return field