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We consider signals and operators in finite dimension which have sparse time-frequency representations. As main result we show that an $S$-sparse Gabor representation in $\mathbb{C}^n$ with respect to a random unimodular window can be…

Classical Analysis and ODEs · Mathematics 2007-11-16 Goetz E. Pfander , Holger Rauhut

We present Selective Non-Gaussian Refinement (SNGR), a SLAM framework that augments iSAM2 with targeted nested sampling on windows where Gaussian approximations are likely to fail. We detect such regions using the condition number of joint…

Robotics · Computer Science 2026-04-27 Anushka Kulkarni , Sarthak Dubey

In this article we introduce a broad family of adaptive, linear time-frequency representations termed superposition frames, and show that they admit desirable fast overlap-add reconstruction properties akin to standard short-time Fourier…

Numerical Analysis · Mathematics 2010-04-20 Daniel Rudoy , Prabahan Basu , Patrick J. Wolfe

Estimation of a sparse spectral precision matrix, the inverse of a spectral density matrix, is a canonical problem in frequency-domain analysis of high-dimensional time series (HDTS), with applications in neurosciences and environmental…

Methodology · Statistics 2025-11-11 Navonil Deb , Amy Kuceyeski , Sumanta Basu

Recent prominence in 3D Gaussian Splatting (3DGS) has enabled real-time rendering while maintaining high-fidelity novel view synthesis. However, 3DGS resorts to the Gaussian function that is low-pass by nature and is restricted in…

Computer Vision and Pattern Recognition · Computer Science 2025-08-08 Junyu Zhou , Yuyang Huang , Wenrui Dai , Junni Zou , Ziyang Zheng , Nuowen Kan , Chenglin Li , Hongkai Xiong

We address the problem of signal reconstruction from intensity measurements with respect to a measurement frame. This non-convex inverse problem is known as phase retrieval. The case considered in this paper concerns phaseless measurements…

Functional Analysis · Mathematics 2019-02-13 Goetz E. Pfander , Palina Salanevich

We consider three problems for Gabor frames that have recently received much attention. The first problem concerns the approximation of dual Gabor frames in $L_2(R)$ by finite-dimensional methods. Utilizing Wexler-Raz type duality relations…

Functional Analysis · Mathematics 2025-10-20 Thomas Strohmer

We provide the foundations of a Hilbert space theory for the short-time Fourier transform (STFT) where the flat tori \begin{equation*} \mathbb{T}_{N}^2=\mathbb{R}^2/(\mathbb{Z}\times N\mathbb{Z})=[0,1]\times \lbrack 0,N] \end{equation*} act…

Functional Analysis · Mathematics 2023-10-24 Luis Daniel Abreu , Peter Balazs , Nicki Holighaus , Franz Luef , Michael Speckbacher

In this paper we construct frames of Gabor type for the space $L^2_{rad}(\R^d)$ of radial $L^2$-functions, and more generally, for subspaces of modulation spaces consisting of radial distributions. Hereby, each frame element itself is a…

Functional Analysis · Mathematics 2016-09-07 Holger Rauhut

Time-frequency (TF) representation of non-stationary signals typically requires the effective concentration of energy distribution along the instantaneous frequency (IF) ridge, which exhibits intrinsic sparsity. Inspired by the sparse…

Signal Processing · Electrical Eng. & Systems 2025-01-15 Zongyue Yang , Baoqing Ding , Shibin Wang , Chuang Sun , Xuefeng Chen

Statistical inference for time series such as curve estimation for time-varying models or testing for existence of change-point have garnered significant attention. However, these works are generally restricted to the assumption of…

Statistics Theory · Mathematics 2024-08-08 Soham Bonnerjee , Sayar Karmakar , Wei Biao Wu

Despite 3D Gaussian Splatting (3DGS) excelling in most configurations, it lacks generalization across novel viewpoints in a few-shot scenario because it overfits to the sparse observations. We revisit 3DGS optimization from a machine…

Computer Vision and Pattern Recognition · Computer Science 2025-11-25 Youngsik Yun , Dongjun Gu , Youngjung Uh

Recent years have witnessed the rapid emergence of 3D Gaussian splatting (3DGS) as a powerful approach for 3D reconstruction and novel view synthesis. Its explicit representation with Gaussian primitives enables fast training, real-time…

Computer Vision and Pattern Recognition · Computer Science 2026-04-20 Haato Watanabe , Nobuyuki Umetani

This article introduces the Generalized Fourier Series (GFS), a novel spectral method that extends the clas- sical Fourier series to non-periodic functions. GFS addresses key challenges such as the Gibbs phenomenon and poor convergence in…

Numerical Analysis · Mathematics 2025-10-17 Narsimha Reddy Rapakaa , Mohamed Kamel Riahi

In this paper, we derive the improved uniform error bounds for the long-time dynamics of the $d$-dimensional $(d=2,3)$ nonlinear space fractional sine-Gordon equation (NSFSGE). The nonlinearity strength of the NSFSGE is characterized by…

Numerical Analysis · Mathematics 2024-02-29 Junqing Jia , Xiaoqing Chi , Xiaoyun Jiang

This article deals with the use of optimal lattice and optimal window in Discrete Gabor Transform computation. In the case of a generalized Gaussian window, extending earlier contributions, we introduce an additional local window adaptation…

We develop a fast variational approximation scheme for Gaussian process (GP) regression, where the spectrum of the covariance function is subjected to a sparse approximation. Our approach enables uncertainty in covariance function…

Computation · Statistics 2019-04-24 Linda S. L. Tan , Victor M. H. Ong , David J. Nott , Ajay Jasra

This paper presents a novel boundary-optimized fast Fourier extension algorithm for efficient approximation of non-periodic functions. The proposed methodology constructs periodic extensions through strategic utilization of boundary…

Numerical Analysis · Mathematics 2025-08-27 Z. Y. Zhao , Y. F Wang , A. G. Yagola

We show that there exist complete and minimal systems of time-frequency shifts of Gaussians in $L^2(\mathbb{R})$ which are not strong Markushevich basis (do not admit the spectral synthesis). In particular, it implies that there is no…

Complex Variables · Mathematics 2018-12-06 Anton Baranov , Yurii Belov , Alexander Borichev

The present paper is devoted to the semiclassical analysis of linear Schr\"odinger equations from a Gabor frame perspective. We consider (time-dependent) smooth Hamiltonians with at most quadratic growth. Then we construct higher order…

Analysis of PDEs · Mathematics 2015-01-28 Michele Berra , Martina Bulai , Elena Cordero , Fabio Nicola