scholarly journals Analyses on limitations of coherent field imaging principle

2014 ◽  
Vol 63 (10) ◽  
pp. 104203
Author(s):  
Si Qing-Dan ◽  
Luo Xiu-Juan ◽  
Zeng Zhi-Hong
Keyword(s):  
Coherent Field ◽  
Field Imaging

Compressed sensing sparse reconstruction for coherent field imaging

2016 ◽  
Vol 25 (4) ◽  
pp. 040701
Author(s):  
Bei Cao ◽  
Xiu-Juan Luo ◽  
Yu Zhang ◽  
Hui Liu ◽  
Ming-Lai Chen
Keyword(s):  
Compressed Sensing ◽  
Sparse Reconstruction ◽  
Coherent Field ◽  
Field Imaging

scholarly journals Four-phase closure algorithm for coherent field imaging

2015 ◽  
Vol 64 (5) ◽  
pp. 054204
Author(s):  
Cao Bei ◽  
Luo Xiu-Juan ◽  
Si Qing-Dan ◽  
Zeng Zhi-Hong
Keyword(s):  
Coherent Field ◽  
Closure Algorithm ◽  
Field Imaging

scholarly journals Improving coherent field imaging quality by suppressing the influence of transmitting aperture spacing error

2015 ◽  
Vol 64 (12) ◽  
pp. 124203
Author(s):  
Cheng Zhi-Yuan ◽  
Ma Cai-Wen ◽  
Luo Xiu-Juan ◽  
Zhang Yu ◽  
Zhu Xiang-Ping ◽  
...  
Keyword(s):  
Imaging Quality ◽  
Coherent Field ◽  
Field Imaging

Detector Noise Quantitative Ratio Modelling in Coherent Field Imaging

2015 ◽  
Vol 44 (4) ◽  
pp. 407002
Author(s):  
程志远 CHENG Zhi-yuan ◽  
罗秀娟 LUO Xiu-juan ◽  
马彩文 MA Cai-wen ◽  
张羽 ZHANG Yu ◽  
刘辉 LIU Hui ◽  
...  
Keyword(s):  
Detector Noise ◽  
Quantitative Ratio ◽  
Coherent Field ◽  
Field Imaging

scholarly journals Optical transfer function of coherent field imaging based on deviation of receptors

2013 ◽  
Vol 62 (22) ◽  
pp. 224201
Author(s):  
Xiang Li-Bin ◽  
Zhang Wen-Xi ◽  
Wu Zhou ◽  
L Xiao-Yu ◽  
Li Yang ◽  
...  
Keyword(s):  
Transfer Function ◽  
Optical Transfer Function ◽  
Coherent Field ◽  
Optical Transfer ◽  
Field Imaging

scholarly journals Resolution of coherent field imaging technique

2013 ◽  
Vol 62 (16) ◽  
pp. 164203
Author(s):  
Zhang Wen-Xi ◽  
Xiang Li-Bin ◽  
Kong Xin-Xin ◽  
Li Yang ◽  
Wu Zhou ◽  
...  
Keyword(s):  
Imaging Technique ◽  
Coherent Field ◽  
Field Imaging

scholarly journals All-phase target reconstruction method for coherent field imaging

2015 ◽  
Vol 64 (12) ◽  
pp. 124205
Author(s):  
Cao Bei ◽  
Luo Xiu-Juan ◽  
Chen Ming-Lai ◽  
Zhang Yu
Keyword(s):  
Reconstruction Method ◽  
Coherent Field ◽  
Field Imaging

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Detection of a point defect in a silicon single crystal by high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 466-467
Author(s):  
M. Awaji
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Point Defect ◽  
Point Defects ◽  
Noise Level ◽  
Dark Field ◽  
Silicon Single Crystal ◽  
High Resolution Image ◽  
Dark Field Imaging ◽  
Field Imaging

It is necessary to improve the resolution, brightness and signal-to-noise ratio(s/n) for the detection and identification of point defects in crystals. In order to observe point defects, multi-beam dark-field imaging is one of the useful methods. Though this method can improve resolution and brightness compared with dark-field imaging by diffuse scattering, the problem of s/n still exists. In order to improve the exposure time due to the low intensity of the dark-field image and the low resolution, we discuss in this paper the bright-field high-resolution image and the corresponding subtracted image with reference to a changing noise level, and examine the possibility for in-situ observation, identification and detection of the movement of a point defect produced in the early stage of damage process by high energy electron bombardment.The high-resolution image contrast of a silicon single crystal in the [10] orientation containing a triple divacancy cluster is calculated using the Cowley-Moodie dynamical theory and for a changing gaussian noise level. This divacancy model was deduced from experimental results obtained by electron spin resonance. The calculation condition was for the lMeV Berkeley ARM operated at 800KeV.

Quantitative analysis by reconstruction of HREM focal series

1994 ◽  
Vol 52 ◽  
pp. 740-741
Author(s):  
W. Coene ◽  
A. Thust ◽  
M. Op de Beeck ◽  
D. Van Dyck
Keyword(s):  
Phase Retrieval ◽  
Image Plane ◽  
Initial Guess ◽  
Recursive Least Squares ◽  
Objective Lens ◽  
Electron Wave ◽  
Electron Sources ◽  
Original Algorithm ◽  
Coherent Field ◽  
Direct Interpretation

Compared to conventional electron sources, the use of a highly coherent field-emission gun (FEG) in TEM improves the information resolution considerably. A direct interpretation of this extra information, however, is hampered since amplitude and phase of the electron wave are scrambled in a complicated way upon transfer from the specimen exit plane through the objective lens towards the image plane. In order to make the additional high-resolution information interpretable, a phase retrieval procedure is applied, which yields the aberration-corrected electron wave from a focal series of HRTEM images (Coene et al, 1992).Kirkland (1984) tackled non-linear image reconstruction using a recursive least-squares formalism in which the electron wave is modified stepwise towards the solution which optimally matches the contrast features in the experimental through-focus series. The original algorithm suffers from two major drawbacks : first, the result depends strongly on the quality of the initial guess of the first step, second, the processing time is impractically high.

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