def laplacian_pyramid_image(shape, n_levels=4, sd=None):
"""Simple laplacian pyramid paramaterization of an image.
For more flexibility, use a sum of lowres_tensor()s.
Args:
shape: shape of resulting image, [batch, width, height, channels].
n_levels: number of levels of laplacian pyarmid.
sd: standard deviation of param initialization.
Returns:
tensor with shape from first argument.
"""
batch_dims = shape[:-3]
w, h, ch = shape[-3:]
pyramid = 0
for n in range(n_levels):
k = 2 ** n
pyramid += lowres_tensor(shape, batch_dims + (w // k, h // k, ch), sd=sd)
return pyramid
def naive(shape, sd=None):
return lowres_tensor(shape, shape, sd=sd)