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Computing the Lipschitz Constant Needed for Fast Scene Recovery from CASSI Measurements

Overgaard, Niels Christian LU and Holst, Anders LU orcid (2024) 18th European Conference on Computer Vision, ECCV 2024 In Lecture Notes in Computer Science 15120. p.339-353
Abstract
The linear inverse problem associated with the standard model for hyperspectral image recovery from CASSI measurements is considered. This is formulated as the minimization of an objective function which is the sum of a total variation regularizer and a least squares loss function. Standard first-order iterative minimization algorithms, such as ISTA, FISTA and TwIST, require as input the value of the Lipschitz constant for the gradient of the loss function, or at least a good upper bound on this value, in order to select appropriate step lengths. For the loss term considered here, this Lipschitz constant equals the square of the largest singular value of the measurement map. In applications, this number is usually computed directly as the... (More)
The linear inverse problem associated with the standard model for hyperspectral image recovery from CASSI measurements is considered. This is formulated as the minimization of an objective function which is the sum of a total variation regularizer and a least squares loss function. Standard first-order iterative minimization algorithms, such as ISTA, FISTA and TwIST, require as input the value of the Lipschitz constant for the gradient of the loss function, or at least a good upper bound on this value, in order to select appropriate step lengths. For the loss term considered here, this Lipschitz constant equals the square of the largest singular value of the measurement map. In applications, this number is usually computed directly as the largest eigenvalue of a huge square matrix. This can sometimes become a bottleneck in an otherwise optimized algorithm. In the present paper we effectively eliminate this bottleneck for CASSI reconstructions by showing how the Lipschitz constant can be calculated from a square matrix whose size is easily three orders of magnitudes smaller than in the direct approach.

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publication status
published
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host publication
Computer Vision – ECCV 2024 : 18th European Conference, Milan, Italy, September 29–October 4, 2024, Proceedings, Part LXII - 18th European Conference, Milan, Italy, September 29–October 4, 2024, Proceedings, Part LXII
series title
Lecture Notes in Computer Science
volume
15120
pages
15 pages
publisher
Springer
conference name
18th European Conference on Computer Vision, ECCV 2024
conference location
Milan, Italy
conference dates
2024-09-29 - 2024-10-04
external identifiers
  • scopus:85208544942
ISSN
0302-9743
1611-3349
ISBN
978-3-031-73032-0
978-3-031-73033-7
DOI
10.1007/978-3-031-73033-7_19
language
English
LU publication?
yes
id
fb44681b-a2f4-4515-83b8-ea849cfaed02
date added to LUP
2025-01-10 13:16:25
date last changed
2025-05-01 20:34:14
@inproceedings{fb44681b-a2f4-4515-83b8-ea849cfaed02,
  abstract     = {{The linear inverse problem associated with the standard model for hyperspectral image recovery from CASSI measurements is considered. This is formulated as the minimization of an objective function which is the sum of a total variation regularizer and a least squares loss function. Standard first-order iterative minimization algorithms, such as ISTA, FISTA and TwIST, require as input the value of the Lipschitz constant for the gradient of the loss function, or at least a good upper bound on this value, in order to select appropriate step lengths. For the loss term considered here, this Lipschitz constant equals the square of the largest singular value of the measurement map. In applications, this number is usually computed directly as the largest eigenvalue of a huge square matrix. This can sometimes become a bottleneck in an otherwise optimized algorithm. In the present paper we effectively eliminate this bottleneck for CASSI reconstructions by showing how the Lipschitz constant can be calculated from a square matrix whose size is easily three orders of magnitudes smaller than in the direct approach.<br/><br/>}},
  author       = {{Overgaard, Niels Christian and Holst, Anders}},
  booktitle    = {{Computer Vision – ECCV 2024 : 18th European Conference, Milan, Italy, September 29–October 4, 2024, Proceedings, Part LXII}},
  isbn         = {{978-3-031-73032-0}},
  issn         = {{0302-9743}},
  language     = {{eng}},
  pages        = {{339--353}},
  publisher    = {{Springer}},
  series       = {{Lecture Notes in Computer Science}},
  title        = {{Computing the Lipschitz Constant Needed for Fast Scene Recovery from CASSI Measurements}},
  url          = {{http://dx.doi.org/10.1007/978-3-031-73033-7_19}},
  doi          = {{10.1007/978-3-031-73033-7_19}},
  volume       = {{15120}},
  year         = {{2024}},
}