Improved visual performance in letter perception through edge orientation encoding in a retinal prosthesis simulation

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dc.contributor.authorKiral-Kornek, Isabell
dc.contributor.authorO'Sullivan-Green, Elma
dc.contributor.authorSavage, Craig
dc.contributor.authorMcCarthy, Chris
dc.contributor.authorGrayden, David
dc.contributor.authorBurkitt, Anthony
dc.date.accessioned2015-10-05T02:54:24Z
dc.date.available2015-10-05T02:54:24Z
dc.date.issued2014-10
dc.description.abstractObjective. Stimulation strategies for retinal prostheses predominately seek to directly encode image brightness values rather than edge orientations. Recent work suggests that the generation of oriented elliptical phosphenes may be possible by controlling interactions between neighboring electrodes. Based on this, we propose a novel stimulation strategy for prosthetic vision that extracts edge orientation information from the intensity image and encodes it as oriented elliptical phosphenes. We test the hypothesis that encoding edge orientation via oriented elliptical phosphenes leads to better alphabetic letter recognition than standard intensity-based encoding. Approach. We conduct a psychophysical study with simulated phosphene vision with 12 normal-sighted volunteers. The two stimulation strategies were compared with variations of letter size, electrode drop-out and spatial offsets of phosphenes. Main results. Mean letter recognition accuracy was significantly better with the new proposed stimulation strategy (65%) compared to direct grayscale encoding (47%). All examined parameters-stimulus size, phosphene dropout, and location shift-were found to influence the performance, with significant two-way interactions between phosphene dropout and stimulus size as well as between phosphene dropout and phosphene location shift. The analysis delivers a model of perception performance. Significance. Displaying available directional information to an implant user may improve their visual performance. We present a model for designing a stimulation strategy under the constraints of existing retinal prostheses that can be exploited by retinal implant developers to strategically employ oriented phosphenes.en_US
dc.description.sponsorshipThis research was supported by the Australian Research Council (ARC) through its Special Research Initiative (SRI)in Bionic Vision Australia (BVA). The Bionics Institute acknowledges the support it receives from the Victorian Government through its Operational Infrastructure Support Program. This work was supported by the Australian Federal and Victorian State Governments and the Australian Research Council through the ICT Centre of Excellence program,National ICT Australia (NICTA).en_US
dc.identifier.citationKiral-Kornek, F. I., E. O'Sullivan-Green, C. O. Savage, C. McCarthy, D. B. Grayden and A. N. Burkitt (2014). Improved visual performance in letter perception through edge orientation encoding in a retinal prosthesis simulation. Journal of Neural Engineering 11(6): 066002.en_US
dc.identifier.urihttp://repository.bionicsinstitute.org:8080/handle/123456789/135
dc.language.isoenen_US
dc.publisherIOP Publishingen_US
dc.subjectvisual acuityen_US
dc.subjectretinal implanten_US
dc.subjectvisual psychophysicsen_US
dc.subjectletter recognitionen_US
dc.titleImproved visual performance in letter perception through edge orientation encoding in a retinal prosthesis simulationen_US
dc.typeArticleen_US
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