An Extended Reweighted <inline-formula><math display="inline"><semantics><mrow><msub><mo>ℓ</mo><mn>1</mn></msub></mrow></semantics></math></inline-formula> Minimization Algorithm for Image Restoration

This paper proposes an effective extended reweighted <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mo>ℓ</mo><mn>1</mn></msub></mrow></semantics><...

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Bibliographic Details
Main Authors: Sining Huang, Yupeng Chen, Tiantian Qiao
Format: Article
Language:English
Published: MDPI AG 2021-12-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/9/24/3224
Description
Summary:This paper proposes an effective extended reweighted <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mo>ℓ</mo><mn>1</mn></msub></mrow></semantics></math></inline-formula> minimization algorithm (ERMA) to solve the basis pursuit problem <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><munder><mrow><mi>min</mi></mrow><mrow><mi>u</mi><mo>∈</mo><msup><mi>R</mi><mi>n</mi></msup></mrow></munder><mrow><mo stretchy="false">{</mo><mrow><msub><mrow><mo stretchy="false">|</mo><mo stretchy="false">|</mo><mi>u</mi><mo stretchy="false">|</mo><mo stretchy="false">|</mo></mrow><mn>1</mn></msub><mo>:</mo><mrow><mrow><mi>A</mi><mi>u</mi><mo>=</mo><mi>f</mi></mrow><mo stretchy="false">}</mo></mrow></mrow></mrow></mrow></semantics></math></inline-formula> in compressed sensing, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mo>∈</mo><msup><mi>R</mi><mrow><mi>m</mi><mo>×</mo><mi>n</mi></mrow></msup></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>m</mi><mo>≪</mo><mi>n</mi></mrow></semantics></math></inline-formula>. The fast algorithm is based on linearized Bregman iteration with soft thresholding operator and generalized inverse iteration. At the same time, it also combines the iterative reweighted strategy that is used to solve <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><munder><mrow><mi>min</mi></mrow><mrow><mi>u</mi><mo>∈</mo><msup><mi>R</mi><mi>n</mi></msup></mrow></munder><mrow><mo stretchy="false">{</mo><mrow><msubsup><mrow><mo stretchy="false">|</mo><mo stretchy="false">|</mo><mi>u</mi><mo stretchy="false">|</mo><mo stretchy="false">|</mo></mrow><mi>p</mi><mi>p</mi></msubsup><mo>:</mo><mrow><mrow><mi>A</mi><mi>u</mi><mo>=</mo><mi>f</mi></mrow><mo stretchy="false">}</mo></mrow></mrow></mrow></mrow></semantics></math></inline-formula> problem, with the weight <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>ω</mi><mi>i</mi></msub><mrow><mo stretchy="false">(</mo><mrow><mi>u</mi><mo>,</mo><mi>p</mi></mrow><mo stretchy="false">)</mo></mrow><mo>=</mo><msup><mrow><mrow><mo stretchy="false">(</mo><mrow><mi>ε</mi><mo>+</mo><msup><mrow><mrow><mo stretchy="false">|</mo><mrow><msub><mi>u</mi><mi>i</mi></msub></mrow><mo stretchy="false">|</mo></mrow></mrow><mn>2</mn></msup></mrow><mo stretchy="false">)</mo></mrow></mrow><mrow><mi>p</mi><mo>/</mo><mn>2</mn><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. Numerical experiments show that this <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mo>ℓ</mo><mn>1</mn></msub></mrow></semantics></math></inline-formula> minimization persistently performs better than other methods. Especially when <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo>=</mo><mn>0</mn></mrow></semantics></math></inline-formula>, the restored signal by the algorithm has the highest signal to noise ratio. Additionally, this approach has no effect on workload or calculation time when matrix A is ill-conditioned.
ISSN:2227-7390