scholarly journals Estimation of the Reconstruction Parameters for Atom Probe Tomography

2008 ◽  
Vol 14 (4) ◽  
pp. 296-305 ◽  
Author(s):  
Baptiste Gault ◽  
Frederic de Geuser ◽  
Leigh T. Stephenson ◽  
Michael P. Moody ◽  
Barrington C. Muddle ◽  
...  

The application of wide field-of-view detection systems to atom probe experiments emphasizes the importance of careful parameter selection in the tomographic reconstruction of the analyzed volume, as the sensitivity to errors rises steeply with increases in analysis dimensions. In this article, a self-consistent method is presented for the systematic determination of the main reconstruction parameters. In the proposed approach, the compression factor and the field factor are determined using geometrical projections from the desorption images. A three-dimensional Fourier transform is then applied to a series of reconstructions, and after comparing to the known material crystallography, the efficiency of the detector is estimated. The final results demonstrate a significant improvement in the accuracy of the reconstructed volumes.

Author(s):  
Stefano Cagnoni ◽  
Monica Mordonini ◽  
Luca Mussi ◽  
Giovanni Adorni

Many of the known visual systems in nature are characterized by a wide field of view allowing animals to keep the whole surrounding environment under control. In this sense, dragonflies are one of the best examples: their compound eyes are made up of thousands of separate light-sensing organs arranged to give nearly a 360° field of vision. However, animals with eyes on the sides of their head have high periscopy but low binocularity, that is their views overlap very little. Differently, raptors’ eyes have a central part that permits them to see far away details with an impressive resolution and their views overlap by about ninety degrees. Those characteristics allow for a globally wide field of view and for accurate stereoscopic vision at the same time, which in turn allows for determination of distance, leading to the ability to develop a sharp, three-dimensional image of a large portion of their view. In mobile robotics applications, autonomous robots are required to react to visual stimuli that may come from any direction at any moment of their activity. In surveillance applications, the opportunity to obtain a field of view as wide as possible is also a critical requirement. For these reasons, a growing interest in omnidirectional vision systems (Benosman 2001), which is still a particularly intriguing research field, has emerged. On the other hand, requirements to be able to carry out object/pattern recognition and classification tasks are opposite, high resolution and accuracy and low distortion being possibly the most important ones. Finally, three-dimensional information extraction can be usually achieved by vision systems that combine the use of at least two sensors at the same time. This article presents the class of hybrid dual camera vision systems. This kind of sensors, inspired by existing visual systems in nature, combines an omnidirectional sensor with a perspective moving camera. In this way it is possible to observe the whole surrounding scene at low resolution, while, at the same time, the perspective camera can be directed to focus on objects of interest with higher resolution.


1992 ◽  
Vol 8 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Rosa M. Angulo ◽  
Jesús Dapena

This study compared the errors produced with 3-D video and film analysis techniques using the DLT method with fixed cameras when the images cover a wide field of view. The results indicated that with a large field of view (8 meters) the accuracy of video analysis is clearly inferior to that of film analysis. However, within the volume of the control object, both film and video analyses are still precise enough for most practical purposes. Errors were larger in landmarks outside the control object than in the points of the control object. The maximum errors in the calculated positions of external landmarks were particularly large in the video analysis. However, even these rather large errors for points markedly outside the control object may be acceptable. It will depend on the requirements of each particular investigation.


2021 ◽  
Vol 27 (2) ◽  
pp. 365-384
Author(s):  
Benjamin Klaes ◽  
Rodrigue Lardé ◽  
Fabien Delaroche ◽  
Constantinos Hatzoglou ◽  
Stefan Parvianien ◽  
...  

Abstract


2003 ◽  
Vol 22 (11) ◽  
pp. 1344-1357 ◽  
Author(s):  
A.H. Gee ◽  
G.M. Treece ◽  
R.W. Prager ◽  
C.J.C. Cash ◽  
L. Berman

2009 ◽  
Vol 15 (S2) ◽  
pp. 292-293 ◽  
Author(s):  
BP Geiser ◽  
DJ Larson ◽  
E Oltman ◽  
S Gerstl ◽  
D Reinhard ◽  
...  

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009


Author(s):  
M. G. Lagally

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.


2020 ◽  
Vol 13 (6) ◽  
pp. 1-9
Author(s):  
XU Hong-gang ◽  
◽  
HAN Bing ◽  
LI Man-li ◽  
MA Hong-tao ◽  
...  

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