Resolution enhancement of DEM using photometric stereo method in time-varying shadowed region

Resolution Enhancement In Ultrasonic Imaging By A Time-Varying Filter

10.1117/12.940251 ◽

1987 ◽

Author(s):

N. H. Ching ◽

D. Rosenfeld ◽

M. Braun

Keyword(s):

Resolution Enhancement ◽

Ultrasonic Imaging ◽

Time Varying

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Off-axis electron holography applied to the study of interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121624 ◽

1992 ◽

Vol 50 (1) ◽

pp. 244-245

Author(s):

J.K. Weiss ◽

M. Gajdardziska-Josifovska ◽

M. R. McCartney ◽

David J. Smith

Keyword(s):

Electric Fields ◽

Resolution Enhancement ◽

Interfacial Structure ◽

Atomic Scale ◽

Bulk Property ◽

Electron Holography ◽

Specimen Thickness ◽

Composition And Structure ◽

Chemical Segregation ◽

Diffraction Effects

Interfacial structure is a controlling parameter in the behavior of many materials. Electron microscopy methods are widely used for characterizing such features as interface abruptness and chemical segregation at interfaces. The problem for high resolution microscopy is to establish optimum imaging conditions for extracting this information. We have found that off-axis electron holography can provide useful information for the study of interfaces that is not easily obtained by other techniques.Electron holography permits the recovery of both the amplitude and the phase of the image wave. Recent studies have applied the information obtained from electron holograms to characterizing magnetic and electric fields in materials and also to atomic-scale resolution enhancement. The phase of an electron wave passing through a specimen is shifted by an amount which is proportional to the product of the specimen thickness and the projected electrostatic potential (ignoring magnetic fields and diffraction effects). If atomic-scale variations are ignored, the potential in the specimen is described by the mean inner potential, a bulk property sensitive to both composition and structure. For the study of interfaces, the specimen thickness is assumed to be approximately constant across the interface, so that the phase of the image wave will give a picture of mean inner potential across the interface.

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