Nonlinear phase retrieval using projection operator and iterative wavelet thresholding

V. Davidoiu (1) , B. Sixou (1) , M. Langer (1, 2) , F. Peyrin (1, 2)

1 Imagerie Tomographique et Radiothérapie
2 ESRF - European Synchrotron Radiation Facility

With hard X-rays synchrotron beams, phase contrast can be obtained with the measurement of the Fresnel diffraction intensity patterns associated to a phase shift induced by the object. We have studied the resolution of this inverse problem with an iterative thresholding algorithm in wavelet coordinates combined with an iterative nonlinear method with a Tikhonov regularization and projection operators. The phase retrieval algorithm was tested for a 3D Shepp-Logan phantom in the presence of noise. The results show that the combined approach outperforms the Mixed, the CTF and the nonlinear methods.

Domaines: Traitement du signal et de l'image [eess.SP]

V. Davidoiu, B. Sixou, M. Langer, F. Peyrin. Nonlinear phase retrieval using projection operator and iterative wavelet thresholding. IEEE Signal Processing Letters, 2012, 19 (9), pp.579-582. ⟨10.1109/LSP.2012.2207113⟩. ⟨hal-00798002⟩