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Generalized analytic signal associated with the linear canonical transform (LCT) was proposed recently by Fu and Li ["Generalized Analytic Signal Associated With Linear Canonical Transform," Opt. Commun., vol. 281, pp. 1468-1472, 2008].…

Information Theory · Computer Science 2017-09-21 Soo-Chang Pei , Shih-Gu Huang

An orthogonal approximation for the 8-point discrete cosine transform (DCT) is introduced. The proposed transformation matrix contains only zeros and ones; multiplications and bit-shift operations are absent. Close spectral behavior…

Multimedia · Computer Science 2014-02-26 R. J. Cintra , F. M. Bayer

This paper studies the cosine as basis function for the approximation of univariate and continuous functions without memory. This work studies a supervised learning to obtain the approximation coefficients, instead of using the Discrete…

Signal Processing · Electrical Eng. & Systems 2024-05-28 Ana I. Pérez-Neira , Marc Martinez-Gost , Miguel Ángel Lagunas

Low-Dose computer tomography (LDCT) is an ideal alternative to reduce radiation risk in clinical applications. Although supervised-deep-learning-based reconstruction methods have demonstrated superior performance compared to conventional…

Image and Video Processing · Electrical Eng. & Systems 2024-05-24 Feng Wang , Renfang Wang , Hong Qiu

In recent years there has been a growing interest in the fractional Fourier transform driven by its large number of applications. The literature in this field follows two main routes. On the one hand, the areas where the ordinary Fourier…

Numerical Analysis · Mathematics 2012-01-26 Rafael G. Campos , J. Rico-Melgoza , Edgar Chávez

The discrete cosine transform (DCT) is the key step in many image and video coding standards. The 8-point DCT is an important special case, possessing several low-complexity approximations widely investigated. However, 16-point DCT…

Multimedia · Computer Science 2017-02-08 F. M. Bayer , R. J. Cintra , A. Edirisuriya , A. Madanayake

In this paper, we introduce low-complexity multidimensional discrete cosine transform (DCT) approximations. Three dimensional DCT (3D DCT) approximations are formalized in terms of high-order tensor theory. The formulation is extended to…

Image and Video Processing · Electrical Eng. & Systems 2023-06-21 V. A. Coutinho , R. J. Cintra , F. M. Bayer

Low-dose computed tomography (LDCT) reduces radiation exposure but suffers from image artifacts and loss of detail due to quantum and electronic noise, potentially impacting diagnostic accuracy. Transformer combined with diffusion models…

Image and Video Processing · Electrical Eng. & Systems 2025-07-01 Qiqing Liu , Guoquan Wei , Zekun Zhou , Yiyang Wen , Liu Shi , Qiegen Liu

In this work, we introduce a definition of the Discrete Fourier Transform (DFT) on Euclidean lattices in $\R^n$, that generalizes the $n$-th fold DFT of the integer lattice $\Z^n$ to arbitrary lattices. This definition is not applicable for…

Quantum Physics · Physics 2017-04-04 Lior Eldar , Peter Shor

Low-dose CT (LDCT) imaging attracted a considerable interest for the reduction of the object's exposure to X-ray radiation. In recent years, supervised deep learning (DL) has been extensively studied for LDCT image reconstruction, which…

Image and Video Processing · Electrical Eng. & Systems 2022-10-06 Qiaoqiao Ding , Hui Ji , Yuhui Quan , Xiaoqun Zhang

Discrete transforms such as the discrete Fourier transform (DFT) or the discrete Hartley transform (DHT) furnish an indispensable tool in signal processing. The successful application of transform techniques relies on the existence of the…

Data Structures and Algorithms · Computer Science 2015-08-27 H. M. de Oliveira , R. J. Cintra , R. M. Campello de Souza

Distilling latent diffusion models (LDMs) into ones that are fast to sample from is attracting growing research interest. However, the majority of existing methods face two critical challenges: (1) They hinge on long training using a huge…

Computer Vision and Pattern Recognition · Computer Science 2024-11-08 Qingsong Xie , Zhenyi Liao , Zhijie Deng , Chen chen , Haonan Lu

An exact discretization method is being developed for solving linear systems of ordinary fractional-derivative differential equations with constant matrix coefficients (LSOFDDECMC). It is shown that the obtained linear discrete system in…

Dynamical Systems · Mathematics 2019-03-18 Fikret A. Aliev , N. A. Aliev , N. I. Velieva , K. G. Gasimova , Y. V Mamedova

Stochastic gradient descent in continuous time (SGDCT) provides a computationally efficient method for the statistical learning of continuous-time models, which are widely used in science, engineering, and finance. The SGDCT algorithm…

Probability · Mathematics 2019-06-18 Justin Sirignano , Konstantinos Spiliopoulos

The potential huge advantage of spectral computed tomography (CT) is its capability to provide accuracy material identification and quantitative tissue information. This can benefit clinical applications, such as brain angiography, early…

Image and Video Processing · Electrical Eng. & Systems 2020-08-18 Weiwen Wu , Haijun Yu , Peijun Chen , Fulin Luo , Fenglin Liu , Qian Wang , Yining Zhu , Yanbo Zhang , Jian Feng , Hengyong Yu

Low-dose computed tomography (LDCT) is an important topic in the field of radiology over the past decades. LDCT reduces ionizing radiation-induced patient health risks but it also results in a low signal-to-noise ratio (SNR) and a potential…

Image and Video Processing · Electrical Eng. & Systems 2022-10-03 Wenjun Xia , Qing Lyu , Ge Wang

This study presents the design, discretization and implementation of the continuous-time linear-quadratic model predictive control (CT-LMPC). The control model of the CT-LMPC is parameterized as transfer functions with time delays, and they…

Optimization and Control · Mathematics 2025-03-18 Zhanhao Zhang , Anders Hilmar Damm Christensen , Steen Hørsholt , John Bagterp Jørgensen

In this article, we develop a new method to approximate numerically the fractional Laplacian of functions defined on $\mathbb R$, as well as some more general singular integrals. After mapping $\mathbb R$ into a finite interval, we…

Numerical Analysis · Mathematics 2022-12-13 Jorge Cayama , Carlota M. Cuesta , Francisco de la Hoz , Carlos J. Garcia-Cervera

A fast Discrete Cosine Transform (DCT) algorithm is introduced that can be of particular interest in image processing. The main features of the algorithm are regularity of the graph and very low arithmetic complexity. The 16-point version…

Information Theory · Computer Science 2022-12-29 Maxim Vashkevich , Alexander Petrovsky

This paper proposes a graph linear canonical transform (GLCT) by decomposing the linear canonical parameter matrix into fractional Fourier transform, scale transform, and chirp modulation for graph signal processing. The GLCT enables…

General Mathematics · Mathematics 2024-07-18 Jian Yi Chen , Bing Zhao Li