The　measurement　of　metallic　spherical　objects　in　various　industrial　applications　has　a　significant　role　in　guaranteeing　safety　and　product　quality,　which　can　be　realized　by　the　eddy-current　testing　(ECT)　technique　without　contact.　In　this　study,　for　the　measurement　of　thickness　and　radius　of　nonmagnetic　spherical　shells,　the　original　analytical　model　is　simplified　according　to　the　asymptotic　forms　of　the　modified　spherical　Bessel　functions.　The　simplified　model　contains　only　elementary　functions,　and　can　therefore　accelerates　the　sphere　property　estimation　by　employing　the　optimization　approach　based　on　the　Newton-Raphson　method.　In　numerical　simulation　and　experimental　study,　the　proposed　method　can　provide　accurate　spherical　shell　radii　with　less　computational　time　compared　with　the　original　analytical　model.　©　2001-2012　IEEE.