docs: def sinogram_as_radon(uSin, align=True):
      r"""Compute the phase from a complex wave field sinogram
  
      This step is essential when using the ray approximation before
      computation of the refractive index with the inverse Radon
      transform.
  
      Parameters
      ----------
      uSin: 2d or 3d complex ndarray
          The background-corrected sinogram of the complex scattered wave
          :math:`u(\mathbf{r})/u_0(\mathbf{r})`. The first axis iterates
          through the angles :math:`\phi_0`.
      align: bool
          Tries to correct for a phase offset in the phase sinogram.
  
      Returns
      -------
      phase: 2d or 3d real ndarray
          The unwrapped phase array corresponding to `uSin`.
  
      See Also
      --------
      skimage.restoration.unwrap_phase: phase unwrapping
      radontea.backproject_3d: e.g. reconstruction via backprojection
      """
      ndims = len(uSin.shape)
  
      if ndims == 2:
          # unwrapping is very important
          phiR = np.unwrap(np.angle(uSin), axis=-1)
      else:
          # Unwrap gets the dimension of the problem from the input
          # data. Since we have a sinogram, we need to pass it the
          # slices one by one.
          phiR = np.angle(uSin)
          for ii in range(len(phiR)):
              phiR[ii] = unwrap_phase(phiR[ii], seed=47)
  
      if align:
          align_unwrapped(phiR)
  
      return phiR