Bandlimited Frequency-Constrained Iterative Methods

Variable aperture sampling reconstruction matrices have a history of being computationally intensive due to the need to compute a full matrix inverse. In the field of remote sensing, several spaceborne radiometers and scatterometers, which have irregular sampling and variable apertures, use iterativ...

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Main Authors: Harrison Garrett, David G. Long
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/17/2/236
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author Harrison Garrett
David G. Long
author_facet Harrison Garrett
David G. Long
author_sort Harrison Garrett
collection DOAJ
description Variable aperture sampling reconstruction matrices have a history of being computationally intensive due to the need to compute a full matrix inverse. In the field of remote sensing, several spaceborne radiometers and scatterometers, which have irregular sampling and variable apertures, use iterative techniques to reconstruct measurements of the Earth’s surface. However, many of these iterative techniques tend to over-amplify noise features outside the reconstructable bandwidth. Because the reconstruction of discrete samples is inherently bandlimited, solving a bandlimited inverse can focus on recovering signal features and prevent the over-amplification of noise outside the signal bandwidth. To approximate a bandlimited inverse, we apply bandlimited constraints to several well-known iterative reconstruction techniques: Landweber iteration, additive reconstruction technique (ART), Richardson–Lucy iteration, and conjugate gradient descent. In the context of these iterative techniques, we derive an iterative method for inverting variable aperture samples, taking advantage of the regular and irregular content of variable apertures. We find that this iterative method for variable aperture reconstruction is equivalent to solving a bandlimited conjugate gradient descent algorithm.
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spelling doaj-art-92fa1c32084c44629585805a3b6a928c2025-01-24T13:47:49ZengMDPI AGRemote Sensing2072-42922025-01-0117223610.3390/rs17020236Bandlimited Frequency-Constrained Iterative MethodsHarrison Garrett0David G. Long1Electrical and Computer Engineering Department, Brigham Young University, Provo, UT 84602, USAElectrical and Computer Engineering Department, Brigham Young University, Provo, UT 84602, USAVariable aperture sampling reconstruction matrices have a history of being computationally intensive due to the need to compute a full matrix inverse. In the field of remote sensing, several spaceborne radiometers and scatterometers, which have irregular sampling and variable apertures, use iterative techniques to reconstruct measurements of the Earth’s surface. However, many of these iterative techniques tend to over-amplify noise features outside the reconstructable bandwidth. Because the reconstruction of discrete samples is inherently bandlimited, solving a bandlimited inverse can focus on recovering signal features and prevent the over-amplification of noise outside the signal bandwidth. To approximate a bandlimited inverse, we apply bandlimited constraints to several well-known iterative reconstruction techniques: Landweber iteration, additive reconstruction technique (ART), Richardson–Lucy iteration, and conjugate gradient descent. In the context of these iterative techniques, we derive an iterative method for inverting variable aperture samples, taking advantage of the regular and irregular content of variable apertures. We find that this iterative method for variable aperture reconstruction is equivalent to solving a bandlimited conjugate gradient descent algorithm.https://www.mdpi.com/2072-4292/17/2/236iterative inversebandlimitedresolution enhancementvariable aperturesconjugate gradient descent
spellingShingle Harrison Garrett
David G. Long
Bandlimited Frequency-Constrained Iterative Methods
Remote Sensing
iterative inverse
bandlimited
resolution enhancement
variable apertures
conjugate gradient descent
title Bandlimited Frequency-Constrained Iterative Methods
title_full Bandlimited Frequency-Constrained Iterative Methods
title_fullStr Bandlimited Frequency-Constrained Iterative Methods
title_full_unstemmed Bandlimited Frequency-Constrained Iterative Methods
title_short Bandlimited Frequency-Constrained Iterative Methods
title_sort bandlimited frequency constrained iterative methods
topic iterative inverse
bandlimited
resolution enhancement
variable apertures
conjugate gradient descent
url https://www.mdpi.com/2072-4292/17/2/236
work_keys_str_mv AT harrisongarrett bandlimitedfrequencyconstrainediterativemethods
AT davidglong bandlimitedfrequencyconstrainediterativemethods