title: Restoration of singularities in reconstructed phase of crystal image in electron holography.
abstract: Off-axis electron holography can be used to measure the inner potential of a specimen from its reconstructed phase image and is thus a powerful technique for materials scientists. However, abrupt reversals of contrast from white to black may sometimes occur in a digitally reconstructed phase image, which results in inaccurate information. Such phase distortion is mainly due to the digital reconstruction process and weak electron wave amplitude in some areas of the specimen. Therefore, digital image processing can be applied to the reconstruction and restoration of phase images. In this paper, fringe reconnection processing is applied to phase image restoration of a crystal structure image. The disconnection and wrong connection of interference fringes in the hologram that directly cause a 2π phase jump imperfection are correctly reconnected. Experimental results show that the phase distortion is significantly reduced after the processing. The quality of the reconstructed phase image was improved by the removal of imperfections in the final phase.
authors.affiliation: Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan Global Research Center for Environment and Energy Based on Nanomaterials Science, Nagoya 464-8603, Japan liwei00jp@yahoo.co.jp.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Global Research Center for Environment and Energy Based on Nanomaterials Science, Nagoya 464-8603, Japan EcoTopia Science Institute, Nagoya University, Nagoya 464-8603, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Tanji
keywords: electron holography; image processing; interference fringes; phase restoration; singularities; structure image