title: Digital holographic microscope with automatic focus tracking by detecting sample displacement in real time.
abstract: We propose a new method for focus tracking during the recording of a sequence of digital holograms while the sample experiences axial displacement. Corrected reconstruction distances can be automatically calculated, and well-focused amplitude and phase-contrast images can be obtained for each digitized hologram. The method is demonstrated for inspection of microelectromechanical systems subjected to thermal load. The method can be applied as a quasi-real-time procedure.
authors.affiliation: Istituto per la Microelettronica e Microsistemi del Consigilio Nazionale delle Ricerche, Via P. Castellino 111 80134 Naples, Italy. p.ferraro@cib.na.cnr.it
authors.forename: Pietro
authors.initials: P
authors.lastname: Ferraro
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Coppola
authors.forename: Sergio
authors.initials: S
authors.lastname: De Nicola
authors.forename: Andrea
authors.initials: A
authors.lastname: Finizio
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pierattini