Noncontact method for determination of the fuel assembly height by means of a 3D reconstruction

Author(s):  
Sergey Kravtsov ◽  
Konstantin Rumyantsev
2008 ◽  
Vol 191 (5) ◽  
pp. 1552-1558 ◽  
Author(s):  
Adam L. Summerlin ◽  
Mark E. Lockhart ◽  
Andrew M. Strang ◽  
Peter N. Kolettis ◽  
Naomi S. Fineberg ◽  
...  

Atomic Energy ◽  
2004 ◽  
Vol 97 (2) ◽  
pp. 571-576 ◽  
Author(s):  
A. V. Bushuev ◽  
A. F. Kozhin ◽  
G. Li ◽  
V. N. Zubarev ◽  
A. A. Portnov ◽  
...  

Author(s):  
D. Typke ◽  
G. Pfeifer ◽  
R. Hegerl ◽  
W. Baumeister

The method of quasi-conical tilting for the 3D reconstruction of single macromolecules utilizes the fact that particles tend to adsorb to the supporting film in a few preferred orientations, though with arbitrary azimuthal angles. Therefore, a single electron micrograph of a tilted specimen containing a large number of particle projections provides the data of a conical tilt series with projection directions distributed randomly on a cone. For the selection of particles of equal orientation with respect to the supporting film and for the determination of their azimuth angles, a zero tilt image taken after the minimum dose “tilt image” is utilized.A disadvantage of the method is the large focal range of the tilt image, which e.g. at 30,000× magnification exceeds 5 μm. This, however, can be overcome by small-spot illumination in conjunction with dynamic focusing. For this, the illuminating beam is reduced to a diameter of 50-200 nm, and shifted stepwise or continuously over the object; for each spot position the focus is properly adjusted. Thus the focus range of the whole image is restricted to that of a single spot. Another way to realize dynamic focusing of a tilted object is the use of a narrow slit aperture in the condenser C2, thus illuminating a straight line parallel to the tilt axis.


2018 ◽  
Vol 7 (3.13) ◽  
pp. 51
Author(s):  
S Kravtsov ◽  
K Rumyantsev

A method for determining the head height of fuel assemblies in the reactor core of a nuclear power unit using a 3-D reconstruction of a stereopair of collinear images is considered. The method is based on the principle of statistical evaluation of the height of a set of points for a 3-D reconstruction of the contour of the head of the fuel assembly. To obtain a stereopair of images, it is suggested to use a collinear digital stereo-vision system. A model experiment was carried out. The results are compared with the known method for determining the height of the heads of fuel assemblies, based on an estimate of the height of the centers of gravity of the contours of fuel assembly heads. The proposed method shows a higher accuracy in solving the problem of determining the heights of fuel assembly heads in comparison with the known method.  


2018 ◽  
Vol 4 (1) ◽  
pp. 517-520 ◽  
Author(s):  
Andreas Wachter ◽  
Jan Kost ◽  
Werner Nahm

AbstractContemporary surgical microscope systems have excellent optical properties but some desirable features remain unavailable. The number of co-observers is currently restricted, by spatial and optical limitations, to only two. Moreover, ergonomics poses are a problem: Current microscope systems impede free movement and sometimes demand that surgeons take uncomfortable postures over long periods of time. To rectify these issues, some companies developed surgical microscope systems based on a streaming approach. These systems remove some of the limitations. Multi-observer positions, for example, are not independent from each other, for example. In order to overcome the aforementioned limitations, we are currently developing an approach for the next generation of surgical microscope: Namely the fully digital surgical microscope, where the current observation system is replaced with a camera array, allowing real-time 3D reconstruction of surgical scenes and, consequently, the rendering of almost unlimited views for multiple observers. These digital microscopes could make the perspective through the microscope unnecessary allowing the surgeon to move freely and work in more comfortable postures. The requirements on the camera array in such a system have to be determined. For this purpose, we propose of estimation the minimal number of cameras and their positions needed for the 3D reconstruction of microsurgical scenes. The method of estimation is based on the requirements for the 3D reconstruction. Within the MATLAB simulation environment, we have developed a 3D model of a microsurgical scene, used for the determination of the number of required cameras. In a next step a small, compact and costefficient system with few opto-mechanical components could be manufactured.


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