[1] Tech Univ Denmark, Dept Mech Engn, DTU Mekan, DK-2800 Lyngby, Denmark
[2] BAM Bundesanstalt Mat Forsch & Prufung, Unter Eichen 87, D-12205 Berlin, Germany
[3] Tech Univ Denmark, Dept Photon Engn, DTU Foton, DK-2800 Lyngby, Denmark
[4] SHUTE Sensing Solut ApS, Diplomvej 381, DK-2800 Lyngby, Denmark