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Doelman, R. (author), Verhaegen, M.H.G. (author)We analyse the very general class of uncertain systems that have Linear Fractional Representations (LFRs), and uncertainty blocks in a convex set with a finite number of vertices. For these systems we design static output feedback controllers. In the general case, computing a robust static output feedback controller with optimal performance...journal article 2017
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Gong, H. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)We present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the...journal article 2017
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Gong, H. (author), Agbana, T.E. (author), Pozzi, P. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)In this Letter, we show that a Shack-Hartmann wavefront sensor can be used for the quantitative measurement of the specimen optical path difference (OPD) in an ordinary incoherent optical microscope, if the spatial coherence of the illumination light in the plane of the specimen is larger than the microscope resolution. To satisfy this...journal article 2017
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Gong, H. (author), Pozzi, P. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)We present a reference-less and time-multiplexing phase retrieval method by making use of the digital micromirror device (DMD). In this method, the DMD functions not only as a flexible binary mask which modulates the optical field, but also as a sampling mask for measuring corresponding phases, which makes the whole setup simple and robust. The...conference paper 2016
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de Visser, C.C. (author), Brunner, A.E. (author), Verhaegen, M.H.G. (author)The distributed-spline-based aberration reconstruction (D-SABRE) method is proposed for distributed wavefront reconstruction with applications to large-scale adaptive optics systems. D-SABRE decomposes the wavefront sensor domain into any number of partitions and solves a local wavefront reconstruction problem on each partition using...journal article 2016
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Yoo, H.W. (author), van Royen, M.E. (author), van Cappellen, WA (author), Houtsmuller, AB (author), Verhaegen, M.H.G. (author), Schitter, G (author)The pinhole plays an important role in confocal laser scanning microscopy (CLSM) for adaptive optics (AO) as well as in imaging, where the size of the pinhole denotes a trade-off between out-of-focus rejection and wavefront distortion. This contribution proposes an AO system for a commercial CLSM with an adjustable square pinhole to cope with...conference paper 2016
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Verstraete, H.R.G.W. (author), Almasian, M. (author), Pozzi, P. (author), Bilderbeek, R (author), Kalkman, J. (author), Faber, DJ (author), Verhaegen, M.H.G. (author)In this manuscript, we present a lens setup for large defocus and astigmatism correction. A deformable defocus lens and two rotational cylindrical lenses are used to control the defocus and astigmatism. The setup is calibrated using a simple model that allows the calculation of the lens inputs so that a desired defocus and astigmatism are...conference paper 2016
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Wilding, D. (author), Pozzi, P. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)Aberrations, scattering and absorption degrade the performance light-sheet fluorescence microscopes (LSFM). An adaptive optics system to correct for these artefacts and to optimize the light-sheet illumination is presented. This system allows a higher axial resolution to be recovered over the field-of-view of the detection objective. It is...conference paper 2016
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Sinquin, B. (author), Verhaegen, M.H.G. (author)We consider the problem of identifying 1D spatially-varying systems that exhibit no temporal dynamics. The spatial dynamics are modeled via a mixed-causal, anti-causal state space model. The methodology is developed for identifying the input-output map of e.g a 1D flexible beam described by the Euler-Bernoulli beam equation and equipped with a...conference paper 2016
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Verhaegen, M.H.G. (author), Hansson, A (author)The identification of multivariable state space models in innovation form is solved in a subspace identification framework using convex nuclear norm optimization. The convex optimization approach allows to include constraints on the unknown matrices in the data-equation characterizing subspace identification methods, such as the lower triangular...journal article 2016
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Agbana, T.E. (author), Yang, H. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)This paper presents experimental results of a static aberration control algorithm based on the linear relation be- tween mean square of the aberration gradient and the second moment of point spread function for the generation of control signal input for a deformable mirror (DM). Results presented in the work of Yang et al.1 suggested a good...conference paper 2016
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Pozzi, P. (author), Wilding, D. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)This proceeding reports early results in the development of a new technique for adaptive optics in confocal microscopy. The term adaptive optics refers to the branch of optics in which an active element in the optical system is used to correct inhomogeneities in the media through which light propagates. In its most classical form, mostly used in...conference paper 2016
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Doelman, R. (author), Verhaegen, M.H.G. (author)We consider the use of the nuclear norm operator, and its tendency to produce low rank results, to provide a convex relaxation of Bilinear Matrix Inequalities (BMIs). The BMI is first written as a Linear Matrix Inequality (LMI) subject to a bi-affine equality constraint and subsequently rewritten into an LMI subject to a rank constraint on a...conference paper 2016
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Yu, C. (author), Verhaegen, M.H.G. (author)In this paper, we study the deterministic blind identification of multiple channel state-space models having a common unknown input using measured output signals that are perturbed by additive white noise sequences. Different from traditional blind identification problems, the considered system is an autoregressive system rather than an FIR...journal article 2016
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Qiu, Y. (author), Van Gijzen, M.B. (author), Van Wingerden, J.W. (author), Verhaegen, M.H.G. (author), Vuik, C. (author)In this manuscript, we study preconditioning techniques for optimal in-domain control of the Navier-Stokes equation, where the control only acts on a few parts of the domain. Optimization and linearization of the optimal in-domain control problem results in a generalized linear saddle-point system. The Schur complement for the generalized saddle...report 2015
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Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)Shack-Hartmann (SH) sensor, based on sampling of wavefront tilts in subapertures, is a simple, reliable, and widely used in adaptive optics wavefront sensor. A wavefront curvature sensor has the advantage of providing the results suitable for direct control of membrane and bimorph deformable mirrors [1], but requires linear registration of...conference paper 2015
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Yu, C. (author), Verhaegen, M.H.G. (author)This paper studies the local identification of large-scale homogeneous systems<br/>with general network topologies. The considered local system identification problem involves unmeasurable signals between neighboring subsystems. Compared with our previous work in Yu et al. (2014) which solves the local identification of 1D homogeneous systems,...conference paper 2015
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Yu, C. (author), Verhaegen, M.H.G. (author), Hansson, A (author)This paper studies the local subspace identification of 1D homogeneous networked systems. The main challenge lies at the unmeasurable interconnection signals between neighboring subsystems. Since there are many unknown inputs to the concerned local system, the corresponding identification problem is semi-blind. To cope with this problem, a...conference paper 2015
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Yu, C. (author), Verhaegen, M.H.G. (author), Kovalsky, S (author), Basri, R (author)The identification of structured state-space model has been intensively studied for a long time but still has not been adequately addressed. The main challenge is that the involved estimation problem is a non-convex (or bilinear) optimization problem. This paper is devoted to developing an identification<br/>method which aims to find the global...conference paper 2015
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Gong, H. (author), Pozzi, P. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)We investigate the possibility of interferometric optical field sensor with DMD forming a series of sampling interferometers in the pupil of an optical system. Our preliminary experiment validates the feasibility of our approach for the field reconstruction in the case of coherent field. We believe that this approach can be extended to sensing...conference paper 2015