Search Results for author: Luca Calatroni

Found 16 papers, 6 papers with code

Whiteness-based bilevel learning of regularization parameters in imaging

no code implementations10 Mar 2024 Carlo Santambrogio, Monica Pragliola, Alessandro Lanza, Marco Donatelli, Luca Calatroni

We consider an unsupervised bilevel optimization strategy for learning regularization parameters in the context of imaging inverse problems in the presence of additive white Gaussian noise.

Bilevel Optimization Image Deconvolution

Deep image prior inpainting of ancient frescoes in the Mediterranean Alpine arc

1 code implementation25 Jun 2023 Fabio Merizzi, Perrine Saillard, Oceane Acquier, Elena Morotti, Elena Loli Piccolomini, Luca Calatroni, Rosa Maria Dessì

The unprecedented success of image reconstruction approaches based on deep neural networks has revolutionised both the processing and the analysis paradigms in several applied disciplines.

Image Reconstruction

Fluctuation-based deconvolution in fluorescence microscopy using plug-and-play denoisers

no code implementations20 Mar 2023 Vasiliki Stergiopoulou, Subhadip Mukherjee, Luca Calatroni, Laure Blanc-Féraud

The spatial resolution of images of living samples obtained by fluorescence microscopes is physically limited due to the diffraction of visible light, which makes the study of entities of size less than the diffraction barrier (around 200 nm in the x-y plane) very challenging.

Denoising Super-Resolution

Beyond $\ell_1$ sparse coding in V1

no code implementations24 Jan 2023 Ilias Rentzeperis, Luca Calatroni, Laurent Perrinet, Dario Prandi

Compared to other methods, soft thresholding achieves this level of sparsity at the expense of much degraded reconstruction performance, that more likely than not is not acceptable in biological vision.

Scaled, inexact and adaptive generalized FISTA for strongly convex optimization

no code implementations11 Jan 2021 Simone Rebegoldi, Luca Calatroni

The proposed algorithm is combined with an adaptive (non-monotone) backtracking strategy, which allows for the adjustment of the algorithmic step-size along the iterations in order to improve the convergence speed.

Deblurring Image Denoising Optimization and Control

A cortical-inspired sub-Riemannian model for Poggendorff-type visual illusions

1 code implementation28 Dec 2020 Emre Baspinar, Luca Calatroni, Valentina Franceschi, Dario Prandi

We consider Wilson-Cowan-type models for the mathematical description of orientation-dependent Poggendorff-like illusions.

Vocal Bursts Type Prediction

Non-convex Super-resolution of OCT images via sparse representation

no code implementations22 Oct 2020 Gabriele Scrivanti, Luca Calatroni, Serena Morigi, Lindsay Nicholson, Alin Achim

We propose a non-convex variational model for the super-resolution of Optical Coherence Tomography (OCT) images of the murine eye, by enforcing sparsity with respect to suitable dictionaries learnt from high-resolution OCT data.

Super-Resolution

On the inverse Potts functional for single-image super-resolution problems

1 code implementation19 Aug 2020 Pasquale Cascarano, Luca Calatroni, Elena Loli Piccolomini

We consider a variational model for single-image super-resolution based on the assumption that the image gradient of the target image is sparse.

Image and Video Processing Numerical Analysis Numerical Analysis 65F22, 65K10 G.1.6; G.1.10; I.4.3; I.4.4; I.4.5; I.4.6

Cortical-inspired Wilson-Cowan-type equations for orientation-dependent contrast perception modelling

no code implementations15 Oct 2019 Marcelo Bertalmío, Luca Calatroni, Valentina Franceschi, Benedetta Franceschiello, Dario Prandi

We consider the evolution model proposed in [9, 6] to describe illusory contrast perception phenomena induced by surrounding orientations.

Space-adaptive anisotropic bivariate Laplacian regularization for image restoration

no code implementations2 Aug 2019 Luca Calatroni, Alessandro Lanza, Monica Pragliola, Fiorella Sgallari

In this paper we present a new regularization term for variational image restoration which can be regarded as a space-variant anisotropic extension of the classical isotropic Total Variation (TV) regularizer.

Image Restoration

A cortical-inspired model for orientation-dependent contrast perception: a link with Wilson-Cowan equations

no code implementations18 Dec 2018 Marcelo Bertalmío, Luca Calatroni, Valentina Franceschi, Benedetta Franceschiello, Dario Prandi

We consider a differential model describing neuro-physiological contrast perception phenomena induced by surrounding orientations.

Anisotropic osmosis filtering for shadow removal in images

1 code implementation17 Sep 2018 Simone Parisotto, Luca Calatroni, Marco Caliari, Carola-Bibiane Schönlieb, Joachim Weickert

We present an anisotropic extension of the isotropic osmosis model that has been introduced by Weickert et al.~(Weickert, 2013) for visual computing applications, and we adapt it specifically to shadow removal applications.

Analysis of PDEs 68U10, 94A08, 49K20, 65M06,

Unveiling the invisible - mathematical methods for restoring and interpreting illuminated manuscripts

1 code implementation19 Mar 2018 Luca Calatroni, Marie d'Autume, Rob Hocking, Stella Panayotova, Simone Parisotto, Paola Ricciardi, Carola-Bibiane Schönlieb

The last fifty years have seen an impressive development of mathematical methods for the analysis and processing of digital images, mostly in the context of photography, biomedical imaging and various forms of engineering.

Image Restoration

Bilevel approaches for learning of variational imaging models

1 code implementation8 May 2015 Luca Calatroni, Cao Chung, Juan Carlos De Los Reyes, Carola-Bibiane Schönlieb, Tuomo Valkonen

We review some recent learning approaches in variational imaging, based on bilevel optimisation, and emphasize the importance of their treatment in function space.

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