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Michaël Unser

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Publications associées (516)

Mmse Denoising Of Sparse Levy Processes Via Message Passing

Michaël Unser, Ulugbek Kamilov, Arash Amini

Many recent algorithms for sparse signal recovery can be interpreted as maximum-a-posteriori (MAP) estimators relying on some specific priors. From this Bayesian perspective, state-of-the-art methods based on discrete-gradient regularizers, such as total-v ...

Ieee2012

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

Michaël Unser, Daniel Sage, Suliana Manley, 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

Compressibility of Deterministic and Random Infinite Sequences

Michaël Unser, Arash Amini

We introduce a definition of the notion of compressibility for infinite deterministic and i.i.d. random sequences which is based on the asymptotic behavior of truncated subsequences. For this purpose, we use asymptotic results regarding the distribution of ...

IEEE2011

Reconstruction of Large, Irregularly Sampled Multidimensional Images. A Tensor-Based Approach

Michaël Unser

Many practical applications require the reconstruction of images from irregularly sampled data. The spline formalism offers an attractive framework for solving this problem; the currently available methods, however, are hard to deploy for large-scale inter ...

Institute of Electrical and Electronics Engineers2011

Image Denoising in Mixed Poisson-Gaussian Noise

Michaël Unser, Thierry Blu, Florian Luisier

We propose a general methodology (PURE-LET) to design and optimize a wide class of transform-domain thresholding algorithms for denoising images corrupted by mixed Poisson-Gaussian noise. We express the denoising process as a linear expansion of thresholds ...

Institute of Electrical and Electronics Engineers2011

3D Steerable Wavelets And Monogenic Analysis For Bioimaging

Michaël Unser

In this paper we introduce a 3D wavelet frame that has the key property of steerability. The proposed wavelet frame relies on the combination of a 3D isotropic wavelet transform with the 3D Riesz operator which brings steerability to the pyramid. The novel ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

A Fast Wavelet-Based Reconstruction Method for Magnetic Resonance Imaging

Michaël Unser, Matthieu Guerquin-Kern

In this work, we exploit the fact that wavelets can represent magnetic resonance images well, with relatively few coefficients. We use this property to improve magnetic resonance imaging (MRI) reconstructions from undersampled data with arbitrary k-space t ...

Institute of Electrical and Electronics Engineers2011

Exact Complex-Wave Reconstruction in Digital Holography

Christian Depeursinge, Michaël Unser, Nicolas Pavillon, Chandra Sekhar Seelamantula

We address the problem of exact complex-wave reconstruction in digital holography. We show that, by confining the object-wave modulation to one quadrant of the frequency domain, and by maintaining a reference-wave intensity higher than that of the object, ...

OSA2011

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

A Primal-Dual Reconstruction Algorithm For Fluorescence And Bioluminescence Tomography

Michaël Unser, Jean-Charles Baritaux

We introduce a new primal-dual reconstruction algorithm for fluorescence and bioluminescence tomography. As often in optical tomography, image reconstruction is performed by optimizing a multi-term convex cost function. Current reconstruction methods emplo ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

Efficient Image Reconstruction Under Sparsity Constraints With Application To Mri And Bioluminescence Tomography

Michaël Unser, Matthieu Guerquin-Kern, Jean-Charles Baritaux

Most bioimaging modalities rely on indirect measurements of the quantity under investigation. The image is obtained as the result of an optimization problem involving a physical model of the measurement system. Due to the ill-posedness of the above problem ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

Stochastic Models for Sparse and Piecewise-Smooth Signals

Michaël Unser, Pouya Dehghani Tafti

We introduce an extended family of continuous-domain stochastic models for sparse, piecewise-smooth signals. These are specified as solutions of stochastic differential equations, or, equivalently, in terms of a suitable innovation model; the latter is ana ...

IEEE2011

Maximum-Likelihood Identification of Sampled Gaussian Processes

Michaël Unser, Simona Maggio, Hagay Kirshner

This work considers sampled data of continuous-domain Gaussian processes. We derive a maximum-likelihood estimator for identifying autoregressive moving average parameters while incorporating the sampling process into the problem formulation. The proposed ...

SampTA2011

Variational Enhancement And Denoising Of Flow Field Images

Michaël Unser, Pouya Dehghani Tafti, Ricard Delgado Gonzalo

In this work we propose a variational reconstruction algorithm for enhancement and denoising of flow fields that is reminiscent of total-variation (TV) regularization used in image processing, but which also takes into account physical properties of flow s ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

Sparsity-Driven Reconstruction for FDOT With Anatomical Priors

Michaël Unser, Martina Bucher, Kai Hassler, Jean-Charles Baritaux, Sebanti Sanyal

In this paper we propose a method based on (2, 1)-mixed-norm penalization for incorporating a structural prior in FDOT image reconstruction. The effect of (2, 1)-mixed-norm penalization is twofold: first, a sparsifying effect which isolates few anatomical ...

Institute of Electrical and Electronics Engineers2011

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

Continuous-Domain ARMA Modeling for Ultrasound Tissue Characterization

Michaël Unser, Simona Maggio

In this study, we investigate the possibility of applying a continuous-time ARMA (CARMA) model to radio-frequency ultrasound signals. We consider the effect of the discretization process on the parameters of the continuous system, and we take into account ...

IEEE2011

On the Hilbert Transform of Wavelets

Michaël Unser, Kunal Narayan Chaudhury

A wavelet is a localized function having a prescribed number of vanishing moments. In this correspondence, we provide precise arguments as to why the Hilbert transform of a wavelet is again a wavelet. In particular, we provide sharp estimates of the locali ...

IEEE2011

Resolution-Invariant Separable Arma Modeling Of Images

Michaël Unser, Aurélien Bourquard, Hagay Kirshner

We suggest a continuous-domain stochastic modeling of images that is invariant to spatial resolution. Specifically, we are proposing an estimator that is calibrated with respect to the sampling step, and that can potentially handle aliased data. Motivated ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

The Ovuscule

Philippe Thévenaz, Michaël Unser, Ricard Delgado Gonzalo

We propose an active contour (a.k.a. snake) that takes the shape of an ellipse. Its evolution is driven by surface terms made of two contributions: the integral of the data over an inner ellipse, counterbalanced by the integral of the data over an outer el ...

IEEE2011

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