In one article I faced with such terms as sSVD, cSVD and oSVD. As I understand sSVD - standart SVD, cSVD - svd for block-circulant matrices, but I can't find what is oSVD. 1) What is oSVD? 2) Can anyone suggest me a few articles about cSVD, oSVD and their implementations?
Looking at the abstract to the paper, this appears to be a term coined by the authors to describe their solution method which uses the singular value decomposition (specialized to make use of the fact that the matrix is a circulant matrix) with some kind of regularization to suppress ringing in the solution.
Unfortunately, the paper is hidden behind a paywall, and my university has no subscription to this journal. TE;DR (Too Expensive; Didn't Read.)
I'm afraid that either the original poster will have to supply more details, or someone who has access to this journal will have to look at the paper to answer the question.