Signal, Image and Video Processing

, Volume 11, Issue 1, pp 41–48 | Cite as

Element-wise uniqueness, prior knowledge, and data-dependent resolution

  • Keith DillonEmail author
  • Yeshaiahu Fainman
Original Paper


Techniques for finding regularized solutions to underdetermined linear systems can be viewed as imposing prior knowledge on the unknown vector. The success of modern techniques, which can impose priors such as sparsity and non-negativity, is the result of advances in optimization algorithms to solve problems which lack closed-form solutions. Techniques for characterization and analysis of the system to determine when information is recoverable, however, still typically rely on closed-form solution techniques such as singular value decomposition or a filter cutoff estimate. In this letter we propose optimization approaches to broaden the approach to system characterization. We start by deriving conditions for when each unknown element of a system admits a unique solution, subject to a broad class of types of prior knowledge. With this approach we can pose a convex optimization problem to find “how unique” each element of the solution is, which may be viewed as a generalization of resolution to incorporate prior knowledge. We find that the result varies with the unknown vector itself, i.e., it is data-dependent, such as when the sparsity of the solution improves the chance it can be uniquely reconstructed. The approach can be used to analyze systems on a case-by-case basis, estimate the amount of important information present in the data, and quantitatively understand the degree to which the regularized solution may be trusted.


Underdetermined Regularization Resolution Super-resolution Sparsity 


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Copyright information

© Springer-Verlag London 2016

Authors and Affiliations

  1. 1.Department of Biomedical EngineeringTulane UniversityNew OrleansUSA
  2. 2.Department of Electrical and Computer EngineeringUniversity of CaliforniaSan DiegoUSA

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