@TECHREPORT\{IMM2006-04874, author = "P. C. Hansen and S. H. Jensen", title = "Subspace-Based Noise Reduction for Speech Signals via Diagonal and Triangular Matrix Decompositions", year = "2006", keywords = "Rank reduction, subspace methods, noise reduction, speech processing, {SVD,} {GSVD,} rank-revealing decompositions, {FIR} filter interpretation, canonical filters.", number = "", series = "IMM-Technical Report-2006-18", institution = "Informatics and Mathematical Modelling, Technical University of Denmark, {DTU}", address = "Richard Petersens Plads, Building 321, {DK-}2800 Kgs. Lyngby", type = "", url = "http://www2.compute.dtu.dk/pubdb/pubs/4874-full.html", abstract = "We survey the definitions and use of rank-revealing matrix decompositions in single-channel noise reduction algorithms for speech signals. Our algorithms are based on the rank-reduction paradigm and, in particular, signal subspace techniques. The focus is on practical working algorithms, using both diagonal (eigenvalue and singular value) decompositions and rank-revealing triangular decompositions ({ULV,} {URV,} {VSV,} {ULLV} and {ULLIV}). In addition we show how the subspace-based algorithms can be evaluated and compared by means of simple {FIR} filter interpretations. The algorithms are illustrated with working Matlab code and applications in speech processing." }