B11-P-07Phase-contrast characteristics of annular bright-field imaging in STEM

Abstract

Noises have great influence on the phase reconstruction of holograms, especially in the gas atmosphere observations. Under noisy conditions, abrupt phase imperfections sometimes occur in a digitally reconstructed phase image, resulting in inaccurate information. In the presentation, computer simulation of electron holography under noisy and low electron luminance conditions will be accomplished and show the efficiency of the proposed restoration processing method [1]. The interference pattern of a CeO2 particle is shown in Fig. (a). One of Poisson noise holograms with λ=8 is shown in Fig. (b). The hologram after adding Gaussian noise is shown in Fig. (c). The hologram with about 25 thousands electrons is shown in Fig. (d). The reconstructed phase image from the noisy electron hologram is shown in Fig. (e). The reconstructed phase image from the corrected interference fringes under noisy situation is shown in Fig. (f). The reconstructed phase image obtained from the corrected interference fringes under noisy and low luminance situation is shown in Fig. (g). The corrected phases show that the method of phase imperfections restoration contributes to the correctly phase reconstruction of the hologram with a quit weak wave intensity and noisy circumstance. [1] W. Li and T. Tanji. Microscopy, 62 (6): 583-588 (2013) Figure: Holograms and reconstructed phase images (a) (b)