Publications by Michaël Unser

A Family of Smooth and Interpolatory Basis Functions for Parametric Curve and Surface Representation

Michaël Unser, Daniel Andreas Schmitter, Ricard Delgado Gonzalo

Interpolatory basis functions are helpful to specify parametric curves or surfaces that can be modified by simple user-interaction. Their main advantage is a characterization of the object by a set of control points that lie on the shape itself (i.e., curv ...

2016

Reconstruction From Multiple Poses in Fluorescence Imaging: Proof of Concept

Michaël Unser, Paul Guichard, Denis Fortun, Ning Chu

One disadvantage of all fluorescence imaging modalities is a poor axial resolution. To overcome this issue, we propose a novel approach to reconstruct fluorescence volumes with isotropic high resolution, from images of particle replicates observed at multi ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Variational Phase Imaging Using the Transport-of-Intensity Equation

Michaël Unser, Daniel Sage, Emrah Bostan, Masih Nilchian, Emmanuel Augustin Julien Froustey

We introduce a variational phase retrieval algorithm for the imaging of transparent objects. Our formalism is based on the transport-of-intensity equation (TIE), which relates the phase of an optical field to the variation of its intensity along the direct ...

IEEE2016

Optical Tomographic Image Reconstruction Based on Beam Propagation and Sparse Regularization

Michaël Unser, Demetri Psaltis, Cédric René Jean Vonesch, Ulugbek Kamilov

Optical tomographic imaging requires an accurate forward model as well as regularization to mitigate missing-data artifacts and to suppress noise. Nonlinear forward models can provide more accurate interpretation of the measured data than their linear coun ...

2016

Exact Algorithms for $ L ^{ 1 } $ -TV Regularization of Real-Valued or Circle-Valued Signals

Michaël Unser, Martin Kurt Storath

We consider

L ^{ 1 }

-TV regularization of univariate signals with values on the real line or on the unit circle. While the real data space leads to a convex optimization problem, the problem is nonconvex for circle-valued data. In this paper, we deriv ...

SIAM2016

Fast 3D reconstruction method for differential phase contrast X-ray CT

Michaël Unser, Masih Nilchian, Michael Thompson McCann, Marco Stampanoni

We present a fast algorithm for fully 3D regularized X-ray tomography reconstruction for both traditional and differential phase contrast measurements. In many applications, it is critical to reduce the X-ray dose while producing high-quality reconstructio ...

2016

SpotCaliper: Fast Wavelet-Based Spot Detection with Accurate Size Estimation

Michaël Unser, Daniel Sage, Zsuzsanna Püspöki, John Paul Ward

Motivation: SpotCaliper is a novel wavelet-based image-analysis software providing a fast automatic detection scheme for circular patterns (spots), combined with the precise estimation of their size. It is implemented as an ImageJ plugin with a friendly us ...

Oxford Journals2016

Hermite Snakes with Control of Tangents

Michaël Unser, Julien René Pierre Fageot, Virginie Sophie Uhlmann

We introduce a new model of parametric contours defined in a continuous fashion. Our curve model relies on Hermite spline interpolation and can easily generate curves with sharp discontinuities; it also grants direct access to the tangent at each location. ...

IEEE2016

An Inner-Product Calculus for Periodic Functions and Curves

Michaël Unser, Daniel Andreas Schmitter, Anaïs Laure Marie-Thérèse Badoual

Our motivation is the design of efficient algorithms to process closed curves represented by basis functions or wavelets. To that end, we introduce an inner-product calculus to evaluate correlations and

L _{ 2 }

distances between such curves. In partic ...

2016

Back-Propagating the Light of Field Stars to Probe Telescope Mirrors Aberrations

Michaël Unser, Frédéric Courbin, Ferréol Arnaud Marie Soulez

We propose a wavefront-based method to estimate the PSF over the whole field of view. This method estimate the aberrations of all the mirrors of the telescope using only field stars. In this proof of concept paper, we described the method and present some ...

SPIE2016

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A Family of Smooth and Interpolatory Basis Functions for Parametric Curve and Surface Representation

Reconstruction From Multiple Poses in Fluorescence Imaging: Proof of Concept

Variational Phase Imaging Using the Transport-of-Intensity Equation

Optical Tomographic Image Reconstruction Based on Beam Propagation and Sparse Regularization

Exact Algorithms for $ L ^{ 1 } $ -TV Regularization of Real-Valued or Circle-Valued Signals

Fast 3D reconstruction method for differential phase contrast X-ray CT

SpotCaliper: Fast Wavelet-Based Spot Detection with Accurate Size Estimation

Hermite Snakes with Control of Tangents

An Inner-Product Calculus for Periodic Functions and Curves

Back-Propagating the Light of Field Stars to Probe Telescope Mirrors Aberrations

Variational Phase Imaging Using the Transport-of-Intensity Equation

Fast 3D reconstruction method for differential phase contrast X-ray CT

Hermite Snakes with Control of Tangents

SpotCaliper: Fast Wavelet-Based Spot Detection with Accurate Size Estimation

An Inner-Product Calculus for Periodic Functions and Curves

A Family of Smooth and Interpolatory Basis Functions for Parametric Curve and Surface Representation

Reconstruction From Multiple Poses in Fluorescence Imaging: Proof of Concept

Back-Propagating the Light of Field Stars to Probe Telescope Mirrors Aberrations

Exact Algorithms for $ L ^{ 1 } $ -TV Regularization of Real-Valued or Circle-Valued Signals

Optical Tomographic Image Reconstruction Based on Beam Propagation and Sparse Regularization