TY - JOUR T1 - Minimisation and Parameter Estimation in Image Restoration Variational Models with ℓ1-Constraints AU - M. Tao JO - East Asian Journal on Applied Mathematics VL - 1 SP - 44 EP - 69 PY - 2018 DA - 2018/02 SN - 8 DO - http://doi.org/10.4208/eajam.210117.060817a UR - https://global-sci.org/intro/article_detail/eajam/10884.html KW - Parameter selection, $ℓ_1$-Constraints, alternating direction method of multipliers, impulsive noise, image processing. AB -
Minimisation of the total variation regularisation for linear operators under $ℓ_1$-constraints applied to image restoration is considered, and relationships between the Lagrange multiplier for a constrained model and the regularisation parameter in an unconstrained model are established. A constrained $ℓ_1$-problem reformulated as a separable convex problem is solved by the alternating direction method of multipliers that includes two sequences, converging to a restored image and the “optimal" regularisation parameter. This allows blurry images to be recovered, with a simultaneous estimation of the regularisation parameter. The noise level parameter is estimated, and numerical experiments illustrate the efficiency of the new approach.