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Showing 1 to 13 of 13 for “"Shack-Hartmann"”.
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Coherence-Gated Wave-Front Sensing in Strongly Scattering Samples
… samples, is presented. This method combines Shack-Hartmann wave-front sensing and phase shifting interferometry (PSI). It employs virtual lenses to mimic the function of a conventional Shack-Hartmann sensor. The use of a modal estimation algorithm allows an approximation of the measured …
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Assembly and proving of a wave front sensing confocal Scanning Laser Ophthalmoscope
… a compact adaptive-optical cSLO. In this work a Shack-Hartmann wave front sensor was implemented into a slightly modified Heidelberg Retina Tomograph (HRT) and aberrations of model eyes were measured. Results show that this system is now ready for testing on living eyes.
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Development of a new Infrared Pyramid Wavefront Sensor
… sensor was chosen due to its advantages over the Shack-Hartmann sensor. It is expected to achieve a gain in terms of sensitivity, raising the limiting magnitude, when used in closed-loop regime. In this work the possibility of building such an instrument has been studied in the framework of a …
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Optimierung einer adaptiven Optik und ihre Anwendung in der ortsaufgelösten Spektroskopie von T Tauri
… für extraterrestrische Physik basiert auf einem Shack-Hartmann-Wellenfrontsensor und ist eines der wenigen Systeme weltweit, die mit einem Laserleitstern ausgerüstet sind. Die effektive Verwendung sowohl leuchtschwacher natürlicher Leitsterne als auch des Laserleitsterns erfordert optimierte …
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Adaptive optics, aberration dynamics and accomodation control. An investigation of the properties of ocular aberrations, and their role in accomodation control.
… of two parts: a report on the use of a binocular Shack-Hartmann (SH) sensor to study the dynamic correlation of ocular aberrations; and the application of an adaptive optics (AO) system to investigate the effect of the manipulation of aberrations on the accommodation control. The binocular SH …
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High-speed video microscopy in optical tweezers
… Durham Smart Imaging. The camera was used in a Shack-Hartmann sensor setup to determine rapidly and non-ambiguously the sign and magnitude of the orbital angular momentum of a helically-phased beam light beam, as an alternative to interferometric techniques. Chapter 4 presents a di- rect …
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Point Spread Function Reconstruction for the Adaptive Optics System ALFA and its Application to Photometry
… algorithm developed for curvature sensors to the Shack-Hartmann sensor (SHS) used on ALFA. The practicability and performance of this algorithm was then tested using simulations of atmospheric turbulence. WFS signals are affected by noise, depending on the brightness of the guide star as well as …
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On-Orbit Characterization of a Microelectromechanical Systems (MEMS) Deformable Mirror (DM): Mission Results from the Deformable Mirror Demonstration Mission (DeMi) CubeSat
… the Boston Micromachines Corporation (BMC) and a Shack-Hartmann wavefront sensor (SHWFS). The mission objectives were on-orbit characterization of the MEMS DM, on-orbit demonstration of closed-loop mirror control, and improvement of the point spread function (PSF) of an astronomical source. This …
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Characterization of the atmospheric turbulence at the Sutherland site and conceptual design study and optimization of an Adaptive Optics system for the Southern African Large Telescope
… refer to the number of subapertures of the Shack-Hartmann wavefront sensor. I conclude with the significant improvement in spectroscopic performance for SALT that could be achieved by implementing an AO system. The gains in encircled/enslited energy are most significant in the near infrared …
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Development of an automated alignment system for the Magdalena Ridge Observatory Interferometer
… of three core components of the AAS: 1. A Shack-Hartmann detector for measuring the angle and position of collimated reference and starlight beams. 2. A dual-wavelength reference light source to be placed near each unit telescope that acts as a bright proxy for starlight. 3. A broadband …
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MCAO for Extremely Large Telescopes: the cases of LBT and E-ELT
… launcher position. The centroiding error in a Shack-Hartmann WFS increases proportionally to the elongation (in a photon noise dominated regime), strongly limiting the performance. To compensate for this effect a straightforward solution is to increase the laser power, i.e. to increase the …
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Phasing of Ground-based Optical Arrays for Space Applications
… atmospheric phase is sensed using a distributed Shack-Hartmann Wavefront Sensor (SHWFS) using light reflected from the target, and corrected using a calibrated feedforward phase offset, (ii) internal phase disturbances are sensed and corrected using Digitally Enhanced Heterodyne Interferometry …
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The effect of aberrations and light scatter on visual performance at photopic and mesopic light levels
… were tested under mesopic conditions. A Shack Hartmann aberrometer was used to take wavefront aberration measurements. No significant regressions were found between aberrations and foveal dip. We concluded that aberrations were probably not the cause of the foveal dip. Q value lenses …