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Pupil Tracking and Control of a Laser Based Power System for a Vision Restoring Retinal ImplantMailhot, Nathaniel 17 January 2019 (has links)
For elderly Canadians, the prevalence of vision impairment caused by degenerative
retinal pathologies, such as age-related macular degeneration and retinitis
pigmentosa, is at an occurrence rate of 14 percent, and on the rise. It has been
shown that visual function can be restored by electrically stimulating intact retinal
tissue with an array of micro-electrodes with suitable signals. Commercial retinal
implants carrying such a micro-electrode array achieve this, but to date must
receive power and data over copper wire cable passing through a permanent surgical
incision in the eye wall (sclera). This project is defined by a collaboration
with iBIONICS, who are developing retinal implants for treatment of such conditions.
iBIONICS has developed the Diamond Eye retinal implant, along with
several technology sub-systems to form a comprehensive and viable medical solution.
Notably, the Diamond Eye system can be powered wirelessly, with no need
for a permanent surgical incision.
The thesis work is focused on the formulation, simulation and hardware demonstration
of a powering system, mounted on glasses frame, for a retinal implant.
The system includes a Micro-Electro-Mechanical System (MEMS) mirror that directs
a laser beam to the implant through the pupil opening. The work presented
here is built on two main components: an iterative predictor-corrector algorithm
(Kalman filter) that estimates pupil coordinates from measurements provided by
an image-based eye tracking algorithm; and an misalignment compensation algorithm
that maps eye pupil coordinates into mirror coordinates, and compensates
for misalignment caused by rigid body motions of the glasses lens mirror and the
MEMS mirror with respect to the eye. Pupil tracker and misalignment compensation
control performance are illustrated through simulated scenarios. The project
also involves the development of a hardware prototype that is used to test algorithms
and related software.
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