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Michaël Unser

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Page 6 of 26

Learning Steerable Wavelet Frames

Michaël Unser

SampTA2011

Laplace-Gradient Wavelet Pyramid and Multiscale Tensor Structures Applied on High-Resolution DEMs

Michaël Unser, Dimitri Nestor Alice Van De Ville, Stéphane Joost, François Golay, Michaël Kalbermatten

University of Zürich2009

A Psf-Based Approach To Biplane Calibration In 3D Super-Resolution Microscopy

Michaël Unser, Suliana Manley, Daniel Sage, Hagay Kirshner, Thomas Pengo

Super-resolution localization microscopy methods such as PALM and STORM have been shown to provide imaging with resolutions up to a few tens of nanometers while using relatively simple setups. Biplane PALM has extended the PALM technique to three-dimension ...

Ieee2012

Divergence-Free Wavelet Frames

Michaël Unser, John Paul Ward, Emrah Bostan

We propose an efficient construction of wavelet frames in any number of dimensions that are divergence-free. Our approach is based on applying the Leray projector, which is scale-invariant, to a standard wavelet frame. We prove that the projected wavelets ...

IEEE Institute of Electrical and Electronics Engineers2015

Blind optimization of algorithm parameters for signal denoising by Monte-Carlo sure

Michaël Unser, Thierry Blu, Sathish Ramani

We consider the problem of optimizing the parameters of an arbitrary denoising algorithm by minimizing Stein's Unbiased Risk Estimate (SURE) which provides a means of assessing the true mean-squared-error (MSE) purely from the measured data assuming that i ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2008

Continuous-Domain Formulation of Inverse Problems for Composite Sparse-Plus-Smooth Signals

Michaël Unser, Shayan Aziznejad, Thomas Jean Debarre

We present a novel framework for the reconstruction of 1D composite signals assumed to be a mixture of two additive components, one sparse and the other smooth, given a finite number of linear measurements. We formulate the reconstruction problem as a cont ...

2021

Coupled Splines for Sparse Curve Fitting

Icíar Lloréns Jover, Michaël Unser, Shayan Aziznejad, Thomas Jean Debarre

We formulate as an inverse problem the construction of sparse parametric continuous curve models that fit a sequence of contour points. Our prior is incorporated as a regularization term that encourages rotation invariance and sparsity. We prove that an op ...

2022

Fast Haar-Wavelet Denoising Of Multidimensional Fluorescence Microscopy Data

Michaël Unser, Thierry Blu, Cédric René Jean Vonesch, Florian Luisier

We propose a novel denoising algorithm to reduce the Poisson noise that is typically dominant in fluorescence microscopy data. To process large datasets at a low computational cost, we use the unnormalized Haar wavelet transform. Thanks to some of its appe ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

Efficient Inversion of Multiple-Scattering Model for Optical Diffraction Tomography

Michaël Unser, Emmanuel Emilien Louis Soubies, Thanh-An Michel Pham

Optical diffraction tomography relies on solving an inverse scattering problem governed by the wave equation. Classical reconstruction algorithms are based on linear approximations of the forward model (Born or Rytov), which limits their applicability to t ...

2017

Image Segmentation With Background Correction Using A Multiplicative Smoothing-Spline Model

Michaël Unser, Aurélien Bourquard, Ramtin Madani

This paper presents an image-segmentation method which compensates multiplicative distortions based on smooth regularity assumptions. In this work, we generalize the original Chan-Vese functional to handle a continuous multiplicative bias. In the derivatio ...

Ieee2012

Jump-Penalized Least Absolute Values Estimation of Scalar or Circle-Valued Signals

Michaël Unser, Martin Kurt Storath

We study jump-penalized estimators based on least absolute deviations which are often referred to as Potts estimators. They are estimators for a parsimonious piecewise constant representation of noisy data having a noise distribution which has heavier tail ...

Oxford University Press2017

Exponential-Spline Wavelet Bases

Michaël Unser, Ildar Khalidov

We build a multiresolution analysis based on shift-invariant exponential B-spline spaces. We construct the basis functions for these spaces and for their orthogonal complements. This yields a new family of wavelet-like basis functions of

L _{ 2 }

, wit ...

IEEE2005

On Regularized Reconstruction of Vector Fields

Michaël Unser, Pouya Dehghani Tafti

In this paper, we give a general characterization of regularization functionals for vector field reconstruction, based on the requirement that the said functionals satisfy certain geometric invariance properties with respect to transformations of the coord ...

IEEE2011

Coupled tomography and distinct-element-method approach to exploring the granular media microstructure in a jamming hourglass

Giorgio Margaritondo, Michaël Unser, Thomas Liebling, Daniel Sage, Lionel Pournin, Slobodan Mitrovic, Marco Ramaioli, Michel Tsukahara, Slobodan Mitrovic, Vincent Gajdosik

We describe an approach for exploring microscopic properties of granular media that couples x-ray microtomography and distinct-element-method (DEM) simulations through image analysis. We illustrate it via the study of the intriguing phenomenon of instant a ...

APS2008

Model-Based Estimation of Three-Dimensional Stiffness Parameters in Photonic-Force Microscopy

Michaël Unser, Andrzej Kulik, Philippe Thévenaz, Elena Bertseva

We propose a system to characterize the 3-D diffusion properties of the probing bead trapped by a photonic-force microscope. We follow a model-based approach, where the model of the dynamics of the bead is given by the Langevin equation. Our procedure comb ...

Institute of Electrical and Electronics Engineers2010

Quantitative evaluation of software packages for single-molecule localization microscopy

Michaël Unser, Suliana Manley, Daniel Sage, Hagay Kirshner, Thomas Pengo

The quality of super-resolution images obtained by single-molecule localization microscopy (SMLM) depends largely on the software used to detect and accurately localize point sources. In this work, we focus on the computational aspects of super-resolution ...

Nature Publishing Group2015

Parametric B-Spline Snakes on Distance Maps—Application to Segmentation of Histology Images

Michaël Unser, Philippe Thévenaz, François Aguet, Chandra Sekhar Seelamantula

We construct parametric active contours (snakes) for outlining cells in histology images. These snakes are defined in terms of cubic B-spline basis functions. We use a steerable ridge detector for obtaining a reliable map of the cell boundaries. Using the ...

EURASIP2008

Steerable Pyramids and Tight Wavelet Frames in L_2(R^d)

Michaël Unser, Dimitri Nestor Alice Van De Ville

We present a functional framework for the design of tight steerable wavelet frames in any number of dimensions. The 2-D version of the method can be viewed as a generalization of Simoncelli's steerable pyramid that gives access to a larger palette of steer ...

Institute of Electrical and Electronics Engineers2011

Learning Weakly Convex Regularizers for Convergent Image-Reconstruction Algorithms

Michaël Unser, Alexis Marie Frederic Goujon, Sebastian Jonas Neumayer

We propose to learn non-convex regularizers with a prescribed upper bound on their weak-convexity modulus. Such regularizers give rise to variational denoisers that minimize a convex energy. They rely on few parameters (less than 15,000) and offer a signal ...

2024

3D Steerable Wavelets in Practice

Michaël Unser

We introduce a systematic and practical design for steerable wavelet frames in 3D. Our steerable wavelets are obtained by applying a 3D version of the generalized Riesz transform to a primary isotropic wavelet frame. The novel transform is self-reversible ...

Institute of Electrical and Electronics Engineers2012