Flexible Quaternion Generalized Minimal Residual Method for Ill-Posed Quaternion Inverse Problems
Xuan Liu, Zhigang Jia, Xiaoqing Jin
TL;DR
This work addresses ill-posed quaternion inverse problems that arise in 3D signal processing and color image restoration by introducing a quaternion total variation (QTV) regularization framework. The authors develop a quaternion collaboratively weighted approach (QIRN) to reformulate QTV into a quaternion Tikhonov problem and solve it efficiently with a flexible quaternion generalized minimal residual method (FQGMRES), accompanied by an improved convergence theory that provides sharp residual bounds. They establish left, right, and flexible preconditioning strategies, along with a robust theoretical basis using quaternion polynomials and minimal polynomials to guarantee convergence. Numerical experiments demonstrate that the proposed QTV-FQGMRES framework outperforms state-of-the-art methods in iteration count, computational time, and color image restoration quality, highlighting its practical impact for fast and accurate quaternion-based inverse problems.
Abstract
The main goal of this paper is to propose a new quaternion total variation regularization model for solving linear ill-posed quaternion inverse problems, which arise from three-dimensional signal filtering or color image processing. The quaternion total variation term in the model is represented by collaborative total variation regularization and approximated by a quaternion iteratively reweighted norm. A novel flexible quaternion generalized minimal residual method is presented to quickly solve this model. An improved convergence theory is established to obtain a sharp upper bound of the residual norm of quaternion minimal residual method (QGMRES). The convergence theory is also presented for preconditioned QGMRES. Numerical experiments indicate the superiority of the proposed model and algorithms over the state-of-the-art methods in terms of iteration steps, CPU time, and the quality criteria of restored color images.
