TY  - JOUR
A1  - Kazasidis, Orestis
A1  - Verpoort, Sven
A1  - Soloviev, Oleg
A1  - Vdovin, Gleb
A1  - Verhaegen, Michel
A1  - Wittrock, Ulrich
T1  - Extended-image-based correction of aberrations using a deformable mirror with hysteresis
JF  - Opt. Expr.
N2  - With a view to the next generation of large space telescopes, we investigate guide-star-free, image-based aberration correction using a unimorph deformable mirror in a plane conjugate to the primary mirror. We designed and built a high-resolution imaging testbed to evaluate control algorithms. In this paper we use an algorithm based on the heuristic hill climbing technique and compare the correction in three different domains, namely the voltage domain, the domain of the Zernike modes, and the domain of the singular modes of the deformable mirror. Through our systematic experimental study, we found that successive control in two domains effectively counteracts uncompensated hysteresis of the deformable mirror.
KW  - active optics, metrics, aberration compensation
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-14759
UR  - https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-26-21-27161&id=398820
VL  - 26
SP  - 27161
EP  - 27178
ER  - 
TY  - CHAP
A1  - Kazasidis, Orestis
A1  - Verpoort, Sven
A1  - Wittrock, Ulrich
T1  - Algorithm design for image-based wavefront control without wavefront sensing
T2  - SPIE Optical Instrument Science, Technology, and Applications, Proc. SPIE
N2  - Active optics is an enabling technology for future large space telescopes. Image-based wavefront control uses an image-sharpness metric to evaluate the optical performance. A control algorithm iteratively adapts a corrective element to maximize this metric, without reconstructing the wavefront. We numerically study a sharpness metric in the space of Zernike modes, and reveal that for large aberrations the Zernike modes are not orthogonal with respect to this metric. The findings are experimentally verified by using a unimorph deformable mirror as
corrective element. We discuss the implications for the correction process and the design of control algorithms.
KW  - active optics, adaptive optics, sharpness metrics, aberration compensation, algorithm design
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-14760
UR  - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10695/1069502/Algorithm-design-for-image-based-wavefront-control-without-wavefront-sensing/10.1117/12.2312523.full
VL  - 10695
SP  - 1069502
ER  - 
TY  - BOOK
ED  - Wittrock, Ulrich
T1  - Adaptive optics for industry and medicine. Proceedings of the 4th International Workshop on Adaptive Optics for Industry and Medicine
Y1  - 2005
UR  - https://www.springer.com/de/book/9783540239789
SN  - 3-540-23978-2
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Grosse-Wentrup, David
A1  - Stier, Alexandra
A1  - Hölscher, Uvo
T1  - Supporting Tool for Usability Specifications
T2  - Dössel, Olaf; Schlegel, Wolfgang C. (Eds.) IFMBE Proceedings World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany Vol. 25/7 Diagnostic and Therapeut
Y1  - 2009
SN  - 978-3-642-03884-6
SP  - 845
EP  - 847
ET  - Springer Berlin Heid
ER  - 
TY  - CHAP
A1  - Verpoort, Sven
A1  - Wittrock, Ulrich
T1  - Miniaturized adaptive mirror for solid state laser resonators
T2  - Proceedings of the 7th International Workshop on Adaptive Optics for Industry and Medicine, Shatura, Russia
Y1  - 2009
ER  - 
TY  - CHAP
A1  - Schulze, M
A1  - Deemann, D
A1  - Hartensuer, R
A1  - Koch, R
A1  - Löhrer, L
A1  - MJ, Raschke
A1  - UM, Hölscher
A1  - Vordemvenne, T.
T1  - A New Combined Optical and Robotic Testing System to Evaluate Multisegmental Spinal Kinematics
T2  - Lim CT, Goh JCH, eds. 6th World Congress of Biomechanics (WCB 2010) August 1-6, 2010 Singapore
Y1  - 2010
SN  - 978-3-642-14515-5
SP  - 580
EP  - 583
PB  - Springer
CY  - Berlin, Heidelberg
ER  - 
TY  - JOUR
A1  - Schulze, M
A1  - Deemann, D
A1  - Hartensuer, R
A1  - Löhrer, L
A1  - MJ, Raschke
A1  - Hölscher, U
A1  - Vordemvenne, T.
T1  - Investigation of multisegmental spinal biomechanics with a combined optical and robotic test setup
JF  - Langenbecks Archives of Surgery
Y1  - 2010
VL  - 395
SP  - 769
EP  - 829
ER  - 
TY  - JOUR
A1  - Schulze, M
A1  - Deemann, D
A1  - Hartensuer, R
A1  - Löhrer, L
A1  - MJ, Raschke
A1  - Hölscher, U
A1  - Vordemvenne, T.
T1  - A new in vitro biomechanical test system to evaluate adjacent level effects of the lumbar spine (P 62)
JF  - European Spine Journal
Y1  - 2010
VL  - 19
SP  - 233
EP  - 364
ER  - 
TY  - JOUR
A1  - Brüggemann, M
A1  - Stier, A
A1  - Hölscher, U
T1  - Sicherer Zustand in Prozessleittechnik und Medizintechnik Safe State in Process Control Engineering and Medical Engineering
JF  - Biomedizinische Technik; ISSN 0013-5585
Y1  - 2010
VL  - 55
ER  - 
TY  - JOUR
A1  - Hölscher, U.
A1  - Liu, L.
A1  - Gruchmann, T.
A1  - Pantiskas, C.
T1  - Cross-National and Cross-Cultural Design of Medical Devices
JF  - AAMI HE 75
Y1  - 2009
ER  -