phase_retrieval

DPCSignal2D.phase_retrieval(method='kottler', mirroring=False, mirror_flip=False)

Retrieve the phase from two orthogonal phase gradients.

Parameters:

• method (‘kottler’, ‘arnison’ or ‘frankot’, optional) – the formula to use, kottler [1] , arnison [2] and frankot [3] are available. The default is ‘kottler’.

• mirroring (bool, optional) – whether to mirror the phase gradients before Fourier transformed. Attempt to reduce boundary effect. The default is False.

• mirror_flip (bool, optional) – only active when ‘mirroring’ is True. Flip the direction of the derivatives which results in negation during signal mirroring. The default is False. If the retrieved phase is not sensible after mirroring, set this to True may resolve it.

Raises:

ValueError – If the method is not implemented

Returns:

signal – the phase retrieved.

Return type:

HyperSpy 2D signal

References

[1]

Kottler, C., David, C., Pfeiffer, F. and Bunk, O., 2007. A two-directional approach for grating based differential phase contrast imaging using hard x-rays. Optics Express, 15(3), p.1175. (Equation 4)

[2]

Arnison, M., Larkin, K., Sheppard, C., Smith, N. and Cogswell, C., 2004. Linear phase imaging using differential interference contrast microscopy. Journal of Microscopy, 214(1), pp.7-12. (Equation 6)

[3]

Frankot, R. and Chellappa, R., 1988. A method for enforcing integrability in shape from shading algorithms. IEEE Transactions on Pattern Analysis and Machine Intelligence, 10(4), pp.439-451. (Equation 21)

Examples

>>> s = pxm.data.dummy_data.get_square_dpc_signal()
>>> s_phase = s.phase_retrieval()
>>> s_phase.plot()