title: Autofocusing in digital holographic phase contrast microscopy on pure phase objects for live cell imaging.
abstract: Digital holography enables a multifocus quantitative phase microscopy for the investigation of reflective surfaces and for marker-free live cell imaging. For digital holographic long-term investigations of living cells an automated (subsequent) robust and reliable numerical focus adjustment is of particular importance. Four numerical methods for the determination of the optimal focus position in the numerical reconstruction and propagation of the complex object waves of pure phase objects are characterized, compared, and adapted to the requirements of digital holographic microscopy. Results from investigations of an engineered surface and human pancreas tumor cells demonstrate the applicability of Fourier-weighting- and gradient-operator-based methods for robust and reliable automated subsequent numerical digital holographic focusing.
authors.affiliation: Center for Biomedical Optics and Photonics, University Medical Center of Muenster, Muenster, Germany. langehanenberg@uni-muenster.de
authors.forename: Patrik
authors.initials: P
authors.lastname: Langehanenberg
authors.forename: Björn
authors.initials: B
authors.lastname: Kemper
authors.forename: Dieter
authors.initials: D
authors.lastname: Dirksen
authors.forename: Gert
authors.initials: G
authors.lastname: von Bally
mesh_terms: D000465:Algorithms; D045744:Cell Line, Tumor; D004867:Equipment Design; D005583:Fourier Analysis; D006696:Holography; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D008853:Microscopy; D008858:Microscopy, Phase-Contrast / Q000379:methods*; D015233:Models, Statistical; D010190:Pancreatic Neoplasms / Q000473:pathology; D012815:Signal Processing, Computer-Assisted