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  - GEN
A1  - Gardemann, J
T1  - 36th annual conference of the German Tropical Pediatric Society (GTP)  February 2-4, 2018   The Ebola-Kindergarten: interim observation unit for children of admitted vhf-patients in Kenema / Sierra Leone 2014
Y1  - 2018
ER  - 
TY  - CHAP
A1  - Remmerbach, Klaus-Ulrich
A1  - Aranzales, Acero
A1  - David, Ivan
T1  - The psychology of money
T2  - ITB-Arbeitsberichte
Y1  - 2018
VL  - 6
ER  - 
TY  - JOUR
A1  - Rupprecht, M.
T1  - Low interest rates and household portfolio behaviour in euro area countries
JF  - Intereconomics - Review of European Economic Policy
Y1  - 2018
U6  - http://dx.doi.org/10.1007/s10272-018-0743-6
SN  - 0020-5346
VL  - 53
IS  - 3
SP  - 174
EP  - 178
ER  - 
TY  - JOUR
A1  - Piroos, A.
A1  - Neffe, C.
A1  - Lattuch, F.
T1  - The way we work: Linking market orientation with internal workplace solutions
JF  - Human Resource Management
Y1  - 2018
VL  - 26
IS  - 3
SP  - 41
EP  - 44
ER  - 
TY  - JOUR
A1  - Annas, S.
A1  - Jantzen, H.-A.
A1  - Scjolz, J.
A1  - Janoschke, U.
T1  - A Scale-up Strategy for the Fluid Flow in Biogas Plants
JF  - Chemical Engineering & Technology
Y1  - 2018
SN  - 1521-4125
IS  - 3
ER  - 
TY  - CHAP
A1  - Tallau, Christian
A1  - Baule, Rainer
T1  - Minimum capital under Basel III: Adequate for the next crisis?
T2  - FIRM Yearbook 2018
Y1  - 2018
SN  - 978-3-00-058858-7
SP  - 135
EP  - 137
CY  - Frankfurt
ER  - 
TY  - GEN
A1  - Kappel, Antonia
A1  - Schiele, Holger
A1  - Buchholz, Wolfgang
T1  - Supplier relationships with competing customers - How can purchasers find out who is the preferred customer?, 27th Annual International Purchasing and Supply Education and Research Association (IPSERA) Conference: "Purchasing and Supply Chain Management: Fostering Innovation", Athens, Greece.
Y1  - 2018
ER  - 
TY  - JOUR
A1  - Neffe, C.
A1  - Lattuch, F.
T1  - Behavior of successful family and non-family executives in German family firms
JF  - Academy of Management Proceedings
Y1  - 2018
VL  - 2018
IS  - 1
ER  -