Development of an auto-focusing fluid lens system

dc.contributor.authorAbdullah, Soran Jalal
dc.date.accessioned2014-11-03T02:09:18Z
dc.date.available2014-11-03T02:09:18Z
dc.date.issued2009
dc.descriptionMasteren_US
dc.description.abstractVariable focal fluid lenses are gaining popularity in many applications where glass lenses were once the only source for optical systems. Due to the new mechanism of the fluid lens, where fluid is the main factor for focus shifting, application of the fluid lens in an automatic focusing system represents an important study for verifying the viability of fluid lenses in automated operations. Therefore, the work undergone in this thesis deals with the development of a fluid lens system that uses image feedback for focusing information. A software algorithm was devised to achieve auto-focus operation, by a number of methods, for binary targets within 1 m distance range. The system comprises two stepper motors – one for moving the target using a guide rail and the other for actuating the syringe-driven pump that injects or withdraws fluid into (or out) of the fluid lens chamber. The lens was made of polydimethylsiloxane (PDMS) polymer which has high optical transmittance. Distilled water, contained in a fluid chamber, was used as the actuating medium. A monochrome CCD camera was directly attached to the fluid lens by an extension tube to capture live images of a binary target. Slope width of pixels intensity profile along a horizontal line across the binary target was chosen as the focus measure value. The auto-focus operation independently varied the lens focal length to arrive at the focused image based on the image feedback analysis. An error-based focusing method was developed that improved the focusing time over the normal focusing method. A comparative modulation transfer function study has shown that the fluid lens image quality resembles that of a glass lens at low spatial frequency whereas glass lens performs better at high spatial frequency.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/202
dc.language.isoenen_US
dc.subjectBiological Scienceen_US
dc.subjectFluid lens systemen_US
dc.titleDevelopment of an auto-focusing fluid lens systemen_US
dc.typeThesisen_US
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