Comparison of three 3D scanning techniques for paintings, as applied to Vermeer’s ‘Girl with a Pearl Earring’

A seventeenth-century canvas painting is usually comprised of varnish and (translucent) paint layers on a substrate. A viewer’s perception of a work of art can be affected by changes in and damages to these layers. Crack formation in the multi-layered stratigraphy of the painting is visible in the surface topology. Furthermore, the impact of...

Model-based Control in Adaptive Optics Systems

Adaptive optics (AO), also called as Smart Optics, has received increasing attention in the past decades. The main idea behind AO is to actively sense and compensate the optical aberration in the system such that the image resolution is improved or the light beam is well focused. The applications of AO include ground-based telescopes, scanning...

Model-based aberration correction in a closed-loop wavefront-sensor-less adaptive optics system

In many scientific and medical applications, such as laser systems and microscopes, wavefront-sensor-less (WFSless) adaptive optics (AO) systems are used to improve the laser beam quality or the image resolution by correcting the wavefront aberration in the optical path. The lack of direct wavefront measurement in WFSless AO systems imposes a...

Extracting hysteresis from nonlinear measurement of wavefront-sensorless adaptive optics system

In many scientific and medical applications wavefront-sensorless adaptive optics (AO) systems are used to correct the wavefront aberration by optimizing a certain target parameter, which is nonlinear with respect to the control signal to the deformable mirror (DM). Hysteresis is the most common nonlinearity of DMs, which can be corrected if the...

Multiplexing control of a multichannel piezoelectric deformable mirror

Addressing of massive arrays of piezoelectric actuators is usually achieved by using separate high-voltage output drivers, one per channel. This approach applied to high-order adaptive optics systems results in complex, expensive and vulnerable to handling abuse driver electronics, hardly scalable to 103-104 actuators. To reduce the number of...