Berlin 2005 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 43: Laser in der Medizin
Q 43.5: Vortrag
Dienstag, 8. März 2005, 15:00–15:15, HU 1070
Ultrafast topometry of living human faces using pulsed holography — •Andrea Thelen1, Susanne Frey1, Sven Hirsch1, Natalie Ladriere1, Jens Bongartz2, Dominik Giel3, and Peter Hering1,4 — 1Stiftung caesar, Ludwig-Erhard-Allee 2, 53175 Bonn — 2now at: RheinAhrCampus, Fachhochschule Koblenz, Südallee 2, 53424 Remagen — 3now at: Fraunhofer Institut IPM, Heiderhofstraße 8, 79110 Freiburg — 4Institut für Lasermedizin, Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf
A hologram contains the entire three-dimensional information of the recorded object and yields therefore the possibility for high-resolving, three-dimensional topometry. With a single pulse of a frequency doubled Nd:YLF laser a hologram of a face is recorded. Due to the extremely short pulse duration of 35 ns no movement artifacts occur. In a second step a cw-laser is used to reconstruct the hologram optically with the complex conjugate reference beam. The so emerging real image is digitized into a set of two-dimensional projections, each containing a focused contour of the face as well as an unfocused background. A focus measure operator extracts the surface information, where the characteristics of the off-axis region are taken into account through an iterative algorithm. Various numerical procedures lead to three-dimensional computer models with an intrinsic gray scale texture which are already used to plan and document surgical interventions in maxillofacial surgery.