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Focus Feedback Control with a Deformable Lens


A. Ruckli

Semester Thesis, SS17

An ongoing challenge in _lm production is continued focus when the object of interest moves in depth with respect to the video camera. Professional _lm productions use dedicated focus pullers (camera assistants) to adjust focus manually. Standard consumer cameras (think DSLRs) employ contrast and phase shift autofocus systems. A different approach is to identify a map that relates object distance to focus state (e.g. focal length, optical-power, focusing lens motor position, etc. depending on the type of lens) and then feed object distance measurements to the map for determining a focus set-point. In this work, we followed this distance/focus mapping approach and created a function that transforms Aruco marker distance to optical-power values for a state-of-the-art Optotune focus-tunable lens. Using this map we designed a focus controller that operates at 30Hz with an accuracy of 0:089 diopters which is in the order of magnitude of the optical-power reproducibility of the lens.

Supervisors: Nikolaos Kariotoglou, Reto Hofmann, Max Polzin, John Lygeros


Type of Publication:

(13)Semester/Bachelor Thesis

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% Autogenerated BibTeX entry
@PhdThesis { Xxx:2017:IFA_5662
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