Abdelhameed Ibrahim Shoji Tominaga Takahiko Horiuchi Material Classification for Printed Circuit Boards by Spectral Imaging System. 216-225 2009 CCIW http://dx.doi.org/10.1007/978-3-642-03265-3_23 conf/cciw/2009 db/conf/cciw/cciw2009.html#IbrahimTH09