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Noom, J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)We present a novel problem formulation for model-free data-driven fault diagnosis, in which possible faults are diagnosed simultaneously to identifying the linear time-invariant system. This problem is practically relevant for systems whose model cannot be identified reliably prior to diagnosing possible faults, for instance when operating...journal article 2024
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Noom, J. (author), Smith, C.S. (author), Verbiest, G.J. (author), Katan, A.J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)We propose to use the State Estimation by Sum-of-Norms Regularisation (STATESON-)algorithm for recovering the tip-sample interaction in high-speed tapping mode atomic force microscopy (AFM). This approach enables accurate sample height estimation for each independent cantilever oscillation period, provided that the tip-sample interaction...journal article 2023
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Noom, J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)Model-based fault diagnosis for dynamical systems is a sophisticated task due to model inaccuracies, measurement noise and many possible fault scenarios. By presenting faults in terms of a dictionary, the latter obstacle is recently addressed using well-known techniques for recovering sparse information (e.g. lasso). However, current state-of...journal article 2023
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Hung, S. (author), Llobet Rosell, Arnau (author), Jurriens, Daphne (author), Soloviev, O.A. (author), Kapitein, Lukas C. (author), Grußmayer, K.S. (author), Neukomm, Lukas J. (author), Verhaegen, M.H.G. (author), Smith, C.S. (author)Single-molecule localization microscopy (SMLM) enables the high-resolution visualization of organelle structures and the precise localization of individual proteins. However, the expected resolution is not achieved in tissue as the imaging conditions deteriorate. Sample-induced aberrations distort the point spread function (PSF), and high...journal article 2022
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Kalisvaart, D. (author), Cnossen, J.P. (author), Hung, S. (author), Stallinga, S. (author), Verhaegen, M.H.G. (author), Smith, C.S. (author)Modulation enhanced single-molecule localization microscopy (meSMLM) methods improve the localization precision by using patterned illumination to encode additional position information. Iterative meSMLM (imeSMLM) methods iteratively generate prior information on emitter positions, used to locally improve the localization precision during...journal article 2022
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Malimban, Justin (author), Lathouwers, D. (author), Qian, Haibin (author), Verhaegen, Frank (author), Wiedemann, Julia (author), Brandenburg, Sytze (author), Staring, M. (author)For image-guided small animal irradiations, the whole workflow of imaging, organ contouring, irradiation planning, and delivery is typically performed in a single session requiring continuous administration of anaesthetic agents. Automating contouring leads to a faster workflow, which limits exposure to anaesthesia and thereby, reducing its...journal article 2022
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Qiu, Yue (author), van Gijzen, M.B. (author), van Wingerden, J.W. (author), Verhaegen, M.H.G. (author), Vuik, Cornelis (author)In this article, we study preconditioning techniques for the control of the Navier–Stokes equation, where the control only acts on a few parts of the domain. Optimization, discretization, and linearization of the control problem results in a generalized linear saddle-point system. The Schur complement for the generalized saddle-point system...journal article 2021
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Piscaer, P.J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)This paper presents a computationally efficient framework in which a single focal-plane image is used to obtain a high-resolution reconstruction of dynamic aberrations. Assuming small-phase aberrations, a non-linear Kalman filter implementation is developed whose computational complexity scales close to linearly with the number of pixels of...journal article 2021
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Nguyen, Hieu Thao (author), Soloviev, O.A. (author), Luke, Russell (author), Verhaegen, M.H.G. (author)We develop for the first time a mathematical framework in which the class of projection algorithms can be applied to high numerical aperture (NA) phase retrieval. Within this framework, we first analyze the basic steps of solving the high-NA phase retrieval problem by projection algorithms and establish the closed forms of all the relevant...journal article 2021
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Nguyen, Hieu Thao (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)We present the convergence analysis of convex combination of the alternating projection and Douglas–Rachford operators for solving the phase retrieval problem. New convergence criteria for iterations generated by the algorithm are established by applying various schemes of numerical analysis and exploring both physical and mathematical...journal article 2021
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Colaço Baptista Cerqueira, P. (author), Piscaer, P.J. (author), Verhaegen, M.H.G. (author)This paper presents a computationally efficient wavefront aberration prediction framework for data-driven control in large-scale adaptive optics systems. Our novel prediction algorithm splits prediction into two stages: A highresolution and a low-resolution stage. For the former, we exploit sparsity structures in the system matrices in a data...journal article 2021
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Nguyen, Hieu Thao (author), Bui, Hoa T. (author), Nguyen, Duy Cuong (author), Verhaegen, M.H.G. (author)Motivated by a number of questions concerning transversality-type properties of pairs of sets recently raised by Ioffe and Kruger, this paper reports several new characterizations of the intrinsic transversality property in Hilbert spaces. New results in terms of normal vectors clarify the picture of intrinsic transversality, its variants and...journal article 2020
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Yu, C. (author), Ljung, Lennart (author), Wills, Adrian (author), Verhaegen, M.H.G. (author)In this paper, a unified identification framework called constrained subspace method for structured state-space models (COSMOS) is presented, where the structure is defined by a user specified linear or polynomial parametrization. The new approach operates directly from the input and output data, which differs from the traditional two-step...journal article 2020
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Haber, Aleksandar (author), Verhaegen, M.H.G. (author)To develop high-performance controllers for adaptive optics (AO) systems, it is essential to first derive sufficiently accurate state-space models of deformable mirrors (DMs). However, it is often challenging to develop realistic large-scale finite element (FE) state-space models that take into account the system damping, actuator dynamics,...journal article 2020
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Pozzi, P. (author), Smith, C.S. (author), Carroll, E.C.M. (author), Wilding, D. (author), Soloviev, O.A. (author), Booth, Martin (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)Inhomogeneities in the refractive index of a biological microscopy sample can introduce phase aberrations, severely impairing the quality of images. Adaptive optics can be employed to correct for phase aberrations and improve image quality. However, conventional adaptive optics can only correct a single phase aberration for the whole field of...journal article 2020
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Nguyen, Hieu Thao (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)We present an efficient phase retrieval approach for imaging systems with high numerical aperture based on the vectorial model of the point spread function. The algorithm is in the class of alternating minimization methods and can be adjusted for applications with either known or unknown amplitude of the field in the pupil. The algorithm...journal article 2020
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Yu, Chengpu (author), Chen, Jie (author), Li, Shukai (author), Verhaegen, M.H.G. (author)The identification of affinely parameterized state–space system models is quite popular to model practical physical systems or networked systems, and the traditional identification methods require the measurements of both the input and output data. However, in the presence of partial unknown input, the corresponding system identification...journal article 2020
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Doelman, R. (author), Verhaegen, M.H.G. (author)A rank-constrained reformulation of the blind deconvolution problem on images taken with coherent illumination is proposed. Since in the reformulation the rank constraint is imposed on a matrix that is affine in the decision variables, we propose a novel convex heuristic for the blind deconvolution problem. The proposed heuristic allows for...journal article 2019
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Doelman, R. (author), Klingspor, Måns (author), Hansson, Anders (author), Löfberg, Johan (author), Verhaegen, M.H.G. (author)To optimally compensate for time-varying phase aberrations with adaptive optics, a model of the dynamics of the aberrations is required to predict the phase aberration at the next time step. We model the time-varying behavior of a phase aberration, expressed in Zernike modes, by assuming that the temporal dynamics of the Zernike coefficients...journal article 2019
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Piscaer, P.J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)A new wavefront sensorless adaptive optics method is presented that can accurately correct for time-varying aberrations using a single focal plane image at each sample instance. The linear relation between the mean square of the aberration gradient and the change in second moment of the image forms the basis of the presented method. The new...journal article 2019