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49 Results Found

  • Feature Paper
  • Article
  • Open Access
3 Citations
1,273 Views
15 Pages

20 May 2025

Quaternion tensor decompositions have recently been the center of focus due to their wide potential applications in color data processing. In this paper, we establish a simultaneous decomposition for a quaternion tensor quaternity under Einstein prod...

(This article belongs to the Special Issue Advanced Numerical Linear Algebra)
  • Article
  • Open Access
24 Citations
4,766 Views
21 Pages

28 May 2021

To protect the copyright of the color image, a color image watermarking scheme based on quaternion discrete Fourier transform (QDFT) and tensor decomposition (TD) is presented. Specifically, the cover image is partitioned into non-overlapping blocks,...

(This article belongs to the Special Issue Research on Multimedia Systems)
  • Feature Paper
  • Article
  • Open Access
597 Views
25 Pages

This paper extends the theory of equivalence canonical forms from quaternion matrices to quaternion tensors under the Einstein product. Motivated by recent results on the simultaneous decomposition of two specific configurations of five quaternion ma...

  • Article
  • Open Access
7 Citations
2,126 Views
35 Pages

25 October 2024

With the rapid advancement of information technology, digital images such as medical images, grayscale images, and color images are widely used, stored, and transmitted. Therefore, protecting this type of information is a critical challenge. Meanwhil...

  • Article
  • Open Access
4 Citations
2,666 Views
15 Pages

22 February 2023

In this paper, we study the restricted singular-value decomposition (RSVD) for three quaternion tensors under the Einstein product, and give higher-order RSVD over the quaternion algebra, which can achieve simultaneous singular value decomposition of...

(This article belongs to the Section Algebra and Number Theory)
  • Article
  • Open Access
2 Citations
2,207 Views
26 Pages

Elliptic Quaternion Matrices: A MATLAB Toolbox and Applications for Image Processing

  • Hidayet Hüda Kösal,
  • Emre Kişi,
  • Mahmut Akyiğit and
  • Beyza Çelik

6 November 2024

In this study, we developed a MATLAB 2024a toolbox that performs advanced algebraic calculations in the algebra of elliptic numbers and elliptic quaternions. Additionally, we introduce color image processing methods, such as principal component analy...

(This article belongs to the Special Issue Advances in Classical and Applied Mathematics)
  • Article
  • Open Access
1 Citations
1,959 Views
18 Pages

30 June 2022

This article makes use of simultaneous decomposition of four quaternion matrixes to investigate some Sylvester-like quaternion matrix equation systems. We present some useful necessary and sufficient conditions for the consistency of the system of qu...

(This article belongs to the Section B: Mathematics)
  • Article
  • Open Access
6 Citations
2,056 Views
26 Pages

26 July 2024

In this paper, we make use of the simultaneous decomposition of eight quaternion matrices to study the solvability conditions and general solutions to a system of two-sided coupled Sylvester-type quaternion matrix equations AiXiCi+BiXi+1Di=Ωi,i...

(This article belongs to the Section E: Applied Mathematics)
  • Article
  • Open Access
3 Citations
1,768 Views
17 Pages

Elliptic Quaternion Matrices: Theory and Algorithms

  • Hidayet Hüda Kösal,
  • Emre Kişi,
  • Mahmut Akyiğit and
  • Beyza Çelik

24 September 2024

In this study, we obtained results for the computation of eigen-pairs, singular value decomposition, pseudoinverse, and the least squares problem for elliptic quaternion matrices. Moreover, we established algorithms based on these results and provide...

(This article belongs to the Special Issue Advances in Classical and Applied Mathematics)
  • Article
  • Open Access
15 Citations
3,066 Views
20 Pages

12 December 2023

This paper proposes a new method for calculating the quaternion discrete Fourier transform for one-dimensional data. Although the computational complexity of the proposed method still belongs to the O(Nlog2N) class, it allows us to reduce the total n...

(This article belongs to the Special Issue Signal Processing, Sensor Fusion, and Data Fusion in Measurement Systems)
  • Article
  • Open Access
1 Citations
1,493 Views
25 Pages

16 March 2025

In view of the higher requirements of modern machinery for multi-sensor information acquisition and fusion technology, this paper proposes a novel multi-fusion analytic mode decomposition (MFAMD) method to separate and demodulate fault features in si...

(This article belongs to the Special Issue Intelligent Maintenance and Fault Diagnosis of Mobility Equipment)
  • Article
  • Open Access
301 Views
33 Pages

28 September 2026

Reduced biquaternion (RB) matrices provide a commutative algebraic framework for coupled multicomponent data, but their factorizations are usually formulated through complex or real representation matrices. The aim of this study is to develop and val...

(This article belongs to the Special Issue New Trends on the Mathematical Models and Solitons Arising in Real-World Problems, 3rd Edition)
  • Article
  • Open Access
2 Citations
1,545 Views
25 Pages

14 January 2026

Computer vision and deep learning are essential in diverse fields such as autonomous driving, medical imaging, face recognition, and object detection. However, enhancing low-light remote sensing images remains challenging for both research and real-w...

(This article belongs to the Section Artificial Intelligence)
  • Article
  • Open Access
2 Citations
2,566 Views
16 Pages

Quaternion Chromaticity Contrast Preserving Decolorization Method Based on Adaptive Singular Value Weighting

  • Zhiliang Zhu,
  • Mengxi Gao,
  • Xiaojun Huang,
  • Xiaosheng Huang and
  • Yuxiao Zhao

Color image decolorization can not only simplify the complexity of image processing and analysis, improving computational efficiency, but also help to preserve the key information of the image, enhance visual effects, and meet various practical appli...

(This article belongs to the Special Issue Modern Computer Vision and Image Analysis)
  • Article
  • Open Access
1,467 Views
17 Pages

Two algorithms are proposed for the superposition of assemblies of like molecules (e.g., peptide and proteins homooligomers and homoaggregates), which do not require examining all permutations of the molecules. Both start from searching the mutual or...

(This article belongs to the Special Issue Application of Computational Studies for Elucidation of Protein Structure and Function)
  • Article
  • Open Access
1 Citations
2,287 Views
21 Pages

Fast Eigenvalue Decomposition of Arrowhead and Diagonal-Plus-Rank-k Matrices of Quaternions

  • Thaniporn Chaysri,
  • Nevena Jakovčević Stor and
  • Ivan Slapničar

26 April 2024

Quaternions are a non-commutative associative number system that extends complex numbers, first described by Hamilton in 1843. We present algorithms for solving the eigenvalue problem for arrowhead and DPRk (diagonal-plus-rank-k) matrices of quaterni...

(This article belongs to the Section E: Applied Mathematics)
  • Article
  • Open Access
5 Citations
4,864 Views
15 Pages

3 August 2021

Using the orbit decomposition, a new enumerative polynomial P(x) is introduced for abstract (simplicial) complexes of a given type, e.g., trees with a fixed number of vertices or triangulations of the torus with a fixed graph. The polynomial has the...

(This article belongs to the Special Issue Topological Graph Theory and Discrete Geometry)
  • Article
  • Open Access
976 Views
18 Pages

28 April 2026

This paper proposes a novel attitude control methodology for unmanned aerial vehicles (UAVs). The core of the approach is a decomposition of the vehicle’s orientation into a distinct horizontal tilt component and a yaw rotation. This reformulat...

(This article belongs to the Topic Vehicle Dynamics and Control, 2nd Edition)
  • Article
  • Open Access
12 Citations
3,886 Views
28 Pages

19 October 2021

Multi-focus image fusion is an important method used to combine the focused parts from source multi-focus images into a single full-focus image. Currently, to address the problem of multi-focus image fusion, the key is on how to accurately detect the...

(This article belongs to the Special Issue Advances in Image Fusion)
  • Article
  • Open Access
1,919 Views
28 Pages

Some Properties of the Solution to a System of Quaternion Matrix Equations

  • Shao-Wen Yu,
  • Xiao-Na Zhang,
  • Wei-Lu Qin and
  • Zhuo-Heng He

8 December 2022

This paper investigates the properties of the ϕ-skew-Hermitian solution to the system of quaternion matrix equations involving ϕ-skew-Hermicity with four unknowns AiXi(Ai)ϕ+BiXi+1(Bi)ϕ=Ci,(i=1,2,3),A4X4(A4)ϕ=C4. We present th...

(This article belongs to the Section Algebra and Number Theory)
  • Article
  • Open Access
3 Citations
2,133 Views
19 Pages

20 June 2022

Let H be the real quaternion algebra and Hm×n denote the set of all m×n matrices over H. For A∈Hm×n, we denote by Aϕ the n×m matrix obtained by applying ϕ entrywise to the transposed matrix AT, where ϕ is a...

(This article belongs to the Special Issue Selected Papers from the 2021 International Conference on Matrix Inequalities and Matrix Equations)
  • Feature Paper
  • Article
  • Open Access
1 Citations
892 Views
28 Pages

A Color Image Encryption Model Based on a System of Quaternion Matrix Equations

  • Chen-Yang Qi,
  • Chang Liu,
  • Zhuo-Heng He and
  • Shao-Wen Yu

16 January 2026

In the era of big data and multimedia communication, securing color images against unauthorized access and attacks is a pressing challenge. While quaternion-based models provide a unified representation for color images, most existing encryption sche...

  • Article
  • Open Access
1 Citations
1,503 Views
12 Pages

Quaternion SVD-SCMA for 6G Uplink: Exploiting Cross-Polarization Diversity in Hypercomplex 4D Spaces

  • Sergio Vidal-Beltrán,
  • Brenda Lourdes Ramírez-Gómez,
  • Grethell Georgina Pérez-Sánchez,
  • Jesús Yalja Montiel-Pérez and
  • José Luis López-Bonilla

Sixth-generation (6G) networks require advanced non-orthogonal multiple access (NOMA) schemes to support the technical requirements of dense massive machine-type communications (mMTC). While sparse-code multiple access (SCMA) improves uplink spectral...

(This article belongs to the Special Issue Recent Advances in Next-Generation 6G Wireless Networks)
  • Article
  • Open Access
2 Citations
1,659 Views
18 Pages

19 August 2025

In this paper, we present a Mirsky-type unitarily invariant norm inequality for dual quaternion matrices, which can be regarded as a singular value perturbation theorem for dual quaternion matrices. By using this unitarily invariant norm inequality,...

(This article belongs to the Special Issue Exploring Symmetry in Dual Quaternion Matrices and Matrix Equations)
  • Article
  • Open Access
704 Views
20 Pages

26 March 2026

In this paper, a non-decomposition approach is adopted to study the robust stability of quaternion-valued neural networks (QVNNs) with leakage, discrete, and neutral time delays, and the parameter uncertainty is also considered. The existence and uni...

  • Article
  • Open Access
1 Citations
538 Views
22 Pages

4 June 2026

This paper investigates the problem of exponential synchronization for a class of quaternion-valued inertial neural networks with mixed time delays under aperiodic intermittent control. First, a neural network model incorporating both discrete and di...

(This article belongs to the Special Issue Recent Advances in Nonlinear Dynamics: Chaos, Synchronization, and Their Theoretical and Practical Applications)
  • Review
  • Open Access
1 Citations
3,256 Views
40 Pages

Quaternionic and Octonionic Frameworks for Quantum Computation: Mathematical Structures, Models, and Fundamental Limitations

  • Johan Heriberto Rúa Muñoz,
  • Jorge Eduardo Mahecha Gómez and
  • Santiago Pineda Montoya

26 November 2025

We develop detailed quaternionic and octonionic frameworks for quantum computation grounded on normed division algebras. Our central result is to prove the polynomial computational equivalence of quaternionic and complex quantum models: Computation o...

(This article belongs to the Topic Topological, Quantum, and Molecular Information Approaches to Computation and Intelligence)
  • Article
  • Open Access
2 Citations
1,139 Views
22 Pages

CMAWRNet: Multiple Adverse Weather Removal via a Unified Quaternion Neural Architecture

  • Vladimir Frants,
  • Sos Agaian,
  • Karen Panetta and
  • Peter Huang

30 October 2025

Images used in real-world applications such as image or video retrieval, outdoor surveillance, and autonomous driving suffer from poor weather conditions. When designing robust computer vision systems, removing adverse weather such as haze, rain, and...

(This article belongs to the Section Image and Video Processing)
  • Article
  • Open Access
8 Citations
2,605 Views
13 Pages

A Novel Zero Watermarking Based on DT-CWT and Quaternion for HDR Image

  • Jiangtao Huang,
  • Shanshan Shi,
  • Zhouyan He and
  • Ting Luo

29 September 2021

This paper presents a high dynamic range (HDR) image zero watermarking method based on dual tree complex wavelet transform (DT-CWT) and quaternion. In order to be against tone mapping (TM), DT-CWT is used to transform the three RGB color channels of...

(This article belongs to the Special Issue Theory and Applications in Digital Signal Processing)
  • Article
  • Open Access
35 Citations
10,334 Views
23 Pages

Attitude Determination Using a MEMS-Based Flight Information Measurement Unit

  • Der-Ming Ma,
  • Jaw-Kuen Shiau,
  • I.-Chiang Wang and
  • Yu-Heng Lin

22 December 2011

Obtaining precise attitude information is essential for aircraft navigation and control. This paper presents the results of the attitude determination using an in-house designed low-cost MEMS-based flight information measurement unit. This study prop...

(This article belongs to the Section Physical Sensors)
  • Article
  • Open Access
2 Citations
1,555 Views
16 Pages

17 August 2023

In this paper, the adaptive synchronization problem of quaternion-valued Cohen–Grossberg neural networks (QVCGNNs), with and without known parameters, is investigated. On the basis of constructing an appropriate Lyapunov function, and utilizing...

(This article belongs to the Section C2: Dynamical Systems)
  • Article
  • Open Access
240 Views
16 Pages

Three Minimum Variance Distortionless Response Algorithms Based on Quaternion Model for Single MEMS Vector Hydrophone

  • Shan Zhu,
  • Yanan Geng,
  • Keqiang Mu,
  • Yongwei Li and ,
  • Feng Li,
  • Zhiqiang Gao,
  • Yunyue Zhang and
  • Zhicheng Zhao
  • + 3 authors+ 0 author

29 September 2026

To address the limitations of the traditional long-vector model, which cannot adequately preserve the inherent orthogonal structure among channels in the signal processing of a single vector hydrophone, three minimum variance distortionless response...

  • Article
  • Open Access
1 Citations
1,439 Views
19 Pages

Quaternion CNN in Deep Learning Processing for EEG with Applications to Brain Disease Detection

  • Gerardo Ortega-Flores,
  • Guillermo Altamirano-Escobedo,
  • Diego Mercado-Ravell and
  • Eduardo Bayro-Corrochano

28 October 2025

Despite the popularity of electroencephalograms (EEGs) as tools for assessing brain health, they can sometimes be abstract and prone to noise, making them difficult to interpret. The following work aims to implement a Quaternion Convolutional Neural...

(This article belongs to the Special Issue Mechatronic Systems Design and Optimization)
  • Article
  • Open Access
21 Citations
4,283 Views
17 Pages

Static Attitude Determination Using Convolutional Neural Networks

  • Guilherme Henrique dos Santos,
  • Laio Oriel Seman,
  • Eduardo Augusto Bezerra,
  • Valderi Reis Quietinho Leithardt and ,
  • André Sales Mendes and
  • Stéfano Frizzo Stefenon
  • + 1 author+ 0 author

26 September 2021

The need to estimate the orientation between frames of reference is crucial in spacecraft navigation. Robust algorithms for this type of problem have been built by following algebraic approaches, but data-driven solutions are becoming more appealing...

(This article belongs to the Special Issue Sensors for Space Applications)
  • Article
  • Open Access
23 Citations
6,268 Views
26 Pages

PolSAR Image Classification via Learned Superpixels and QCNN Integrating Color Features

  • Xinzheng Zhang,
  • Jili Xia,
  • Xiaoheng Tan,
  • Xichuan Zhou and
  • Tao Wang

6 August 2019

Polarimetric synthetic aperture radar (PolSAR) image classification plays an important role in various PolSAR image application. And many pixel-wise, region-based classification methods have been proposed for PolSAR images. However, most of the pixel...

(This article belongs to the Section Remote Sensing Image Processing)
  • Article
  • Open Access
1,668 Views
18 Pages

Wireless capsule endoscopy (WCE) offers a non-invasive diagnostic alternative for the gastrointestinal tract using a battery-powered capsule. Despite advantages, WCE encounters issues with video quality and diagnostic accuracy, often resulting in mis...

(This article belongs to the Special Issue Biomedical Imaging and Data Analytics for Disease Diagnosis and Treatment, 2nd Edition)
  • Article
  • Open Access
26 Citations
3,355 Views
22 Pages

Hyperspectral Image Enhancement by Two Dimensional Quaternion Valued Singular Spectrum Analysis for Object Recognition

  • Yuxin Lin,
  • Bingo Wing-Kuen Ling,
  • Lingyue Hu,
  • Yiting Zheng and ,
  • Nuo Xu,
  • Xueling Zhou and
  • Xinpeng Wang
  • + 2 authors+ 0 author

25 January 2021

This paper proposes a two dimensional quaternion valued singular spectrum analysis based method for enhancing the hyperspectral image. Here, the enhancement is for performing the object recognition, but neither for improving the visual quality nor su...

(This article belongs to the Special Issue Signal and Image Processing for Remote Sensing)
  • Article
  • Open Access
1 Citations
584 Views
18 Pages

28 January 2026

Unbiased Finite Impulse Response (UFIR) filters are widely used in engineering applications, such as vehicle attitude estimation, due to their advantages, including independence from initial conditions and insensitivity to noise. However, the perform...

(This article belongs to the Special Issue Advanced Filtering, Fusion, and State Estimation in Microsystems and Robotics)
  • Article
  • Open Access
3 Citations
1,167 Views
29 Pages

20 November 2025

Color constancy, the ability to perceive consistent object colors under varying illumination, is a core function of the human visual system and a persistent challenge in machine vision. Retinex theory models this process by decomposing an image S int...

(This article belongs to the Section Computing and Artificial Intelligence)
  • Review
  • Open Access
17 Citations
3,556 Views
81 Pages

21 April 2025

This survey provides a review of the theoretical research on the classic system of matrix equations AX=C and XB=D, which has wide-ranging applications across fields such as control theory, optimization, image processing, and robotics. The paper discu...

(This article belongs to the Special Issue Mathematics: Feature Papers 2025)
  • Article
  • Open Access
18 Citations
947 Views
23 Pages

This paper develops a direct analytical framework for synchronizing and controlling fractional-order octonion-valued fuzzy bidirectional associative memory neural networks (FOOVFBAMNNs). Octonion algebra is neither commutative nor associative, which...

(This article belongs to the Special Issue Advances in Fractional-Order Memristive High-Dimensional Neural Networks: Dynamics, Synchronization, and Brain-Inspired Engineering Applications)
  • Article
  • Open Access
39 Citations
2,799 Views
18 Pages

In this work, we investigate analytically the solutions of a nonlinear div-curl system with fractional derivatives of the Riemann–Liouville or Caputo types. To this end, the fractional-order vector operators of divergence, curl and gradient are ident...

(This article belongs to the Special Issue New Advancements in Pure and Applied Mathematics via Fractals and Fractional Calculus)
  • Article
  • Open Access
1 Citations
675 Views
18 Pages

This paper builds upon a previous study suggesting an optimization procedure for rotation sequences by introducing a fourth factor in Euler-type decompositions, thus allowing for an additional degree of freedom used both as a variational parameter an...

(This article belongs to the Special Issue Applied Mathematical Modelling in Mechanical Design and Analysis)
  • Article
  • Open Access
1,135 Views
18 Pages

A Closed-Form Dual Quaternion Model for Drift Correction in TLS Pose-Circuits

  • Rubens Antonio Leite Benevides,
  • Daniel Rodrigues Dos Santos and
  • Luis Augusto Koenig Veiga

21 November 2025

Laser scanning allows for the rapid acquisition of three-dimensional data in the form of 3D point clouds. However, due to the accumulation of errors in the registration of multiple pairs of point clouds along the sensor’s trajectory, the genera...

(This article belongs to the Collection 3D Imaging and Sensing System)
  • Review
  • Open Access
12 Citations
1,080 Views
85 Pages

12 August 2025

This paper primarily investigates the solutions to the system of equations A1XB1=C1 and A2XB2=C2. This system generalizes the classical equation AXB=C, as well as the system of equations AX=B and XC=D, and finds broad applications in control theory,...

(This article belongs to the Special Issue Mathematics: Feature Papers 2025)
  • Article
  • Open Access
28 Citations
4,991 Views
20 Pages

Screen-Shooting Resilient Watermarking Scheme via Learned Invariant Keypoints and QT

  • Li Li,
  • Rui Bai,
  • Shanqing Zhang,
  • Chin-Chen Chang and
  • Mengtao Shi

30 September 2021

This paper proposes a screen-shooting resilient watermarking scheme via learned invariant keypoints and QT; that is, if the watermarked image is displayed on the screen and captured by a camera, the watermark can be still extracted from the photo. A...

(This article belongs to the Special Issue Security for Mobile Sensing Networks)
  • Technical Note
  • Open Access
4 Citations
3,285 Views
16 Pages

A Closed-Form Solution to Linear Feature-Based Registration of LiDAR Point Clouds

  • Yongbo Wang,
  • Nanshan Zheng,
  • Zhengfu Bian and
  • Hua Zhang

8 September 2021

Due to the high complexity of geo-spatial entities and the limited field of view of LiDAR equipment, pairwise registration is a necessary step for integrating point clouds from neighbouring LiDAR stations. Considering that accurate extraction of poin...

  • Article
  • Open Access
27 Citations
4,860 Views
22 Pages

Prediction of Joint Angles Based on Human Lower Limb Surface Electromyography

  • Hongyu Zhao,
  • Zhibo Qiu,
  • Daoyong Peng,
  • Fang Wang and ,
  • Zhelong Wang,
  • Sen Qiu,
  • Xin Shi and
  • Qinghao Chu
  • + 3 authors+ 0 author

7 June 2023

Wearable exoskeletons can help people with mobility impairments by improving their rehabilitation. As electromyography (EMG) signals occur before movement, they can be used as input signals for the exoskeletons to predict the body’s movement in...

(This article belongs to the Special Issue Human Activity Recognition Using Sensors and Machine Learning)
  • Article
  • Open Access
2 Citations
4,488 Views
31 Pages

27 November 2015

Let \(\mathbf{H}\) be the quaternion algebra. Let \(\mathfrak{g}\) be a complex Lie algebra and let \(U(\mathfrak{g})\) be the enveloping algebra of \(\mathfrak{g}\). The quaternification \(\mathfrak{g}^{\mathbf{H}}=\)\(\,(\,\mathbf{H}\otimes U(\math...