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Bivek Gupta

Publications and source records attributed to Bivek Gupta.

8 recordsLinked to original sources
arXiv2024

A mathematical survey on Fourier type integral transform and their offshoots: windowed Fourier transform, wavelet transform and Stockwell transform

This comprehensive review paper delves into the intricacies of advanced Fourier type integral transforms and their mathematical properties, with a particular focus on fractional Fourier transform (FrFT), linear canonical transform (LCT), quadratic phase Fourier transform (QPFT), and their associated offshoots: windowed Fourier transform, wavelet transform, and Stockwell transform. In the pursuit of a deeper understanding of these transformations, we explore their convolution properties, shedding light on their capacity to define windowed, wavelet and Stockwell transforms in the realm of Fourier, fractional Fourier and quadratic phase Fourier transforms. This review also expands its purview to the realm of uncertainty principles. Several uncertainty principles, like Heisenberg, logarithmic, local, R\'enyi uncertainty principles, etc., within the context of fractional Fourier, linear canonical, and quadratic phase Fourier transforms, as well as their derivative offshoots are presented in the paper both for the functions of complex as well as quatenrion valued. In particular, the counterpart of several important inequalities of classical Fourier transform are also presented in details for the quaternion case. This article also reviews that multiresolution analysis that has been developed in the literature so far.

math.CA↗
arXiv2023

Uncertainty principles associated with the short time quaternion coupled fractional Fourier transform

In this paper, we extend the coupled fractional Fourier transform of a complex valued functions to that of the quaternion valued functions on $\mathbb{R}^4$ and call it the quaternion coupled fractional Fourier transform (QCFrFT). We obtain the sharp Hausdorff-Young inequality for QCFrFT and obtain the associated R\`enyi uncertainty principle. We also define the short time quaternion coupled fractional Fourier transform (STQCFrFT) and explore its important properties followed by the Lieb's and entropy uncertainty principles.

math.GM↗
arXiv2022

Linear Canonical Stockwell Transform and the associated Multiresolution Analysis

In this article, we give a new definition of the linear canonical Stockwell transform (LCST) and study its basic properties along with the inner product relation, reconstruction formula and also characterize the range of the transform and show that its range is the reproducing kernel Hilbert space. We also develop a multiresolution analysis (MRA) associated with the proposed transform together with the construction of the orthonormal basis for $L^2(\mathbb{R}).$

math.FA↗
arXiv2022

Short time quaternion quadratic phase Fourier transform and its uncertainty principles

In this paper, we extend the quadratic phase Fourier transform of a complex valued functions to that of the quaternion valued functions of two variables. We call it the quaternion quadratic phase Fourier transform (QQPFT). Based on the relation between the QQPFT and the quaternion Fourier transform (QFT) we obtain the sharp Hausdorff-Young inequality for QQPFT. We define the short time quaternion quadratic phase Fourier transform (STQQPFT) and explore some of its properties including inner product relation and inversion formula. We find its relation with that of the 2D quaternion ambiguity function and the quaternion Wigner-Ville distribution associated with QQPFT and obtain the Lieb's uncertainty and entropy uncertainty principles for these three transforms.

eess.SP↗
arXiv2022

Linear canonical wavelet transform and the associated uncertainty principles

We define a novel time-frequency analyzing tool, namely linear canonical wavelet transform (LCWT) and study some of its important properties like inner product relation, reconstruction formula and also characterize its range. We obtain Donoho-Stark's and Lieb's uncertainty principle for the LCWT and give a lower bound for the measure of its essential support. We also give Shapiro's mean dispersion theorem for the proposed LCWT.

math.FA↗
arXiv2022

Multidimensional Fractional Wavelet Transforms and Uncertainty Principles

In this paper, we have given a new definition of continuous fractional wavelet transform in $\mathbb{R}^N$, namely the multidimensional fractional wavelet transform (MFrWT) and studied some of the basic properties along with the inner product relation and the reconstruction formula. We have also shown that the range of the proposed transform is a reproducing kernel Hilbert space and obtain the associated kernel. We have obtained the uncertainty principle like Heisenberg's uncertainty principle, logarithmic uncertainty principle and local uncertainty principle of the multidimensional fractional Fourier transform (MFrFT). Based on these uncertainty principles of the MFrFT we have obtained the corresponding uncertainty principles i.e., Heisenberg's, logarithmic and local uncertainty principles for the proposed MFrWT.

math.FA↗
arXiv2019

A note on continuous fractional wavelet transform in $\mathbb{R}^n$

In this paper, we have studied continuous fractional wavelet transform (CFrWT) in $n$-dimensional Euclidean space $\mathbb{R}^n$ with dilation parameter $\boldsymbol a=(a_{1},a_{2},\ldots,a_{n}),$ such that none of $a_{i}'s$ are zero. Necessary and sufficient condition for the admissibility of a function is established with the help of fractional convolution. Inner product relation, reconstruction formula and the reproducing kernel for the CFrWT depending on two wavelets are obtained. Heisenberg's uncertainty inequality and Local uncertainty inequality for the CFrWT are obtained. Finally, boundedness of the transform on the Morrey space $L^{1,ν}_{M}(\mathbb{R}^n)$ and the estimate of $L^{1,ν}_{M}(\mathbb{R}^n)$-distance of the CFrWT of two argument functions with respect to different wavelets are discussed.

math.FA↗