Tomographic Reconstruction for Single Conjugate Adaptive Optics

2012 ◽  
pp. 303-322
Author(s):  
Jenny Niebsch ◽  
Ronny Ramlau
Keyword(s):  
Adaptive Optics ◽  
Tomographic Reconstruction

Static and predictive tomographic reconstruction for wide-field multi-object adaptive optics systems

2013 ◽  
Vol 31 (1) ◽  
pp. 101 ◽  
Author(s):  
C. Correia ◽  
K. Jackson ◽  
J.-P. Véran ◽  
D. Andersen ◽  
O. Lardière ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Tomographic Reconstruction ◽  
Wide Field

Matrix-free tomographic reconstruction for atmospheric turbulence

2019 ◽  
Vol 488 (1) ◽  
pp. 395-400
Author(s):  
Alexandre J T S Mello ◽  
Daniel R Pipa
Keyword(s):  
Atmospheric Turbulence ◽  
Adaptive Optics ◽  
Tomographic Reconstruction ◽  
Memory Requirement ◽  
Alternative Method ◽  
Sparse Methods ◽  
Matrix Free

ABSTRACT Turbulence compensation in astronomy using adaptive optics depends on the use of tomographic techniques to work on wide fields of view. However, classic tomographic methods are computer intensive and consume too much memory to store the tomographic matrix. Recently, various methods have been proposed in an attempt to reduce memory requirements, for example using sparse methods. In this work, we propose a new alternative method that avoids matrices altogether, is faster than classical methods for big systems, and have a very small memory requirement to implement.

scholarly journals Rapid tomographic reconstruction through GPU-based adaptive optics

2018 ◽  
Vol 27 (2) ◽  
pp. 214-226 ◽  
Author(s):  
Carlos González Gutiérrez ◽  
María Luisa Sánchez Rodríguez ◽  
Ramón Ángel Fernández Díaz ◽  
José Luis Calvo Rolle ◽  
Nieves Roqueñí Gutiérrez ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Tomographic Reconstruction

scholarly journals Limitations imposed by optical turbulence profile structure and evolution on tomographic reconstruction for the ELT

2020 ◽  
Vol 494 (2) ◽  
pp. 2773-2784 ◽  
Author(s):  
O J D Farley ◽  
J Osborn ◽  
T Morris ◽  
T Fusco ◽  
B Neichel ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Tomographic Reconstruction ◽  
Large Data ◽  
Atmospheric Conditions ◽  
Optical Turbulence ◽  
Statistical Nature ◽  
Number Of Layers ◽  
Wide Range ◽  
The Impact

ABSTRACT The performance of tomographic adaptive optics (AO) systems is intrinsically linked to the vertical profile of optical turbulence. First, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous turbulence profile. Secondly over the course of an observation, the profile as seen by the telescope changes and the tomographic reconstructor must be updated. These changes can be due to the unpredictable evolution of turbulent layers on meteorological time-scales as short as minutes. Here, we investigate the effect of changing atmospheric conditions on the quality of tomographic reconstruction by coupling fast analytical AO simulation to a large data base of 10 691 high-resolution turbulence profiles measured over two years by the Stereo-SCIDAR instrument at ESO Paranal, Chile. This work represents the first investigation of these effects with a large, statistically significant sample of turbulence profiles. The statistical nature of the study allows us to assess not only the degradation and variability in tomographic error with a set of system parameters (e.g. number of layers and temporal update period), but also the required parameters to meet some error threshold. In the most challenging conditions where the profile is rapidly changing, these parameters must be far more tightly constrained in order to meet this threshold. By providing estimates of these constraints for a wide range of system geometries as well as the impact of different temporal optimization strategies we may assist the designers of tomographic AO for the extremely large telescope to dimension their systems.

Design and calibration of an IVEM for general 3-dimensional imaging of non-diffracting materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1040-1041
Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  
Keyword(s):  
3D Imaging ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3 Dimensional ◽  
3D Microstructure ◽  
Image Translation ◽  
Digital Correlation ◽  
On Line ◽  
Mechanical Stage ◽  
Projection Angle

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

Practical electron tomography

1995 ◽  
Vol 53 ◽  
pp. 742-743
Author(s):  
C.L. Woodcock
Keyword(s):  
Electron Tomography ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3D Shape ◽  
Computational Resources ◽  
Shape Of Particles

Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.Tomographic reconstruction results in a three dimensional description of an individual EM specimen, most commonly a section, and is therefore applicable to problems in which ultrastructural details within the thickness of the specimen are obscured in single micrographs. Information that can be recovered using tomography includes the 3D shape of particles, and the arrangement and dispostion of overlapping fibrous and membranous structures.

TOMOGRAPHIC RECONSTRUCTION OF ASYMMETRIC SPRAYS FROM A TWIN-HOLE AIR SHROUD INJECTOR

1997 ◽  
Vol 7 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Changhyuk Lee ◽  
Suk Ho Chung
Keyword(s):  
Tomographic Reconstruction
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