scholarly journals Phase Corrections With Adaptive Optics and Gerchberg-Saxton Iteration: A Comparison

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 147534-147541 ◽  
Author(s):  
Ming Li
Author(s):  
H.A. Cohen ◽  
W. Chiu

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.


Author(s):  
Carlos Correia ◽  
Henri-Francois Raynaud ◽  
Caroline Kulcsar ◽  
Jean-Marc Conan
Keyword(s):  

2020 ◽  
Vol 10 (10) ◽  
pp. 52-58
Author(s):  
Sergey M. AFONIN ◽  

An electroelastic actuator for nanomechatronics is used in nanotechnology, adaptive optics, microsurgery, microelectronics, and biomedicine to actuate or control mechanisms, systems based on the electroelastic effect, and to convert electrical signals into mechanical displacements and forces. In nanomechatronic systems, a piezoactuator is used in scanning microscopy, laser systems, in astronomy for precision alignment, for compensation of temperature, gravitational deformations and atmospheric turbulence, focusing, and stabilizing the image. In this study, a condition for absolute stability of an electroelastic actuator control system for nanomechatronics under deterministic and random inputs is obtained. A number of equilibrium positions in an electroelastic actuator mechatronic control system are found, the totality of which is represented by a straight line segment. The electroelastic actuator’s deformation control system dead band relative width is determined for the actuator’s symmetric and asymmetric hysteresis characteristics. Under deterministic inputs and with fulfilling the condition for the derivative of the nonlinear hysteresis actuator deformation characteristic, the set of equilibrium positions of the electroelastic actuator control system for nanomechatronics is absolutely stable. Under random inputs, the system absolute stability with respect to the mathematical expectations of the electroelastic actuator mechatronic control system equilibrium positions has been determined subject to fulfilling the condition on the derivative of the actuator hysteresis characteristic.


1989 ◽  
Author(s):  
R. A. Craig ◽  
C. R. Batishko ◽  
J. L. Brimhall ◽  
W. T. Pawlewicz ◽  
K. A. Stahl ◽  
...  

1991 ◽  
Author(s):  
W. J. Gignac ◽  
R. R. Stephens ◽  
A. A. Narayanan ◽  
R. R. Craig ◽  
H. W. Yen
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document