SPIE-the international society for optical engineering;V.507 SPIE-the international society for optical engineering;V.517 SPIE-the international society for optical engineering SPIE-the international Society for optical engineering SPIE-the international society for Optical engineering SPIE-the international society for optial engineering SPIE-the International Society for optical engineering SPIE_the international Society for optical engineering SPIE-The International Society for Optical Engineeringv.518 SPIE-the International Society for Optical Engineering