Image Processing Strategies Dedicated to Visual Cortical Stimulators: A Survey

Buffoni, Louis-Xavier; Coulombe, J.; Sawan, Mohamad

doi:10.1111/j.1525-1594.2005.29104.x

Cited by 34 publications

(18 citation statements)

References 17 publications

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“…A description of surgical difficulties and expected phosphene maps has been published earlier (Srivastava et al 2007). A similar approach to generate phosphene has been suggested by Buffoni et al (2005).…”

Section: Introductionmentioning

confidence: 98%

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Srivastava

Troyk

Dagnelie³

2009

J. Neural Eng.

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In order to assess visual performance using a future cortical prosthesis device, the ability of normally sighted and low vision subjects to adapt to a dotted ‘phosphene’ image was studied. Similar studies have been conduced in the past and adaptation to phosphene maps has been shown but the phosphene maps used have been square or hexagonal in pattern. The phosphene map implemented for this testing is what is expected from a cortical implantation of the arrays of intracortical electrodes, generating multiple phosphenes. The dotted image created depends upon the surgical location of electrodes decided for implantation and the expected cortical response. The subjects under tests were required to perform tasks requiring visual inspection, eye–hand coordination and way finding. The subjects did not have any tactile feedback and the visual information provided was live dotted images captured by a camera on a head-mounted low vision enhancing system and processed through a filter generating images similar to the images we expect the blind persons to perceive. The images were locked to the subject’s gaze by means of video-based pupil tracking. In the detection and visual inspection task, the subject scanned a modified checkerboard and counted the number of square white fields on a square checkerboard, in the eye–hand coordination task, the subject placed black checkers on the white fields of the checkerboard, and in the way-finding task, the subjects maneuvered themselves through a virtual maze using a game controller. The accuracy and the time to complete the task were used as the measured outcome. As per the surgical studies by this research group, it might be possible to implant up to 650 electrodes; hence, 650 dots were used to create images and performance studied under 0% dropout (650 dots), 25% dropout (488 dots) and 50% dropout (325 dots) conditions. It was observed that all the subjects under test were able to learn the given tasks and showed improvement in performance with practice even with a dropout condition of 50% (325 dots). Hence, if a cortical prosthesis is implanted in human subjects, they might be able to perform similar tasks and with practice should be able to adapt to dotted images even with a low resolution of 325 dots of phosphene.

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Section: Introductionmentioning

confidence: 98%

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Srivastava

Troyk

Dagnelie³

2009

J. Neural Eng.

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“…Image segmentation, edge detection [4] and stereo processing techniques for building disparity maps, have been used to aid in navigation. However, these methods do not permit actual object recognition, sought-after in this paper, which calls for more complex processing to adequately extract the information prior to stimulation.…”

Section: Related Workmentioning

confidence: 99%

Image processing system dedicated to a visual intra‐cortical stimulator

Ghannoum

Ghafar-Zadeh²

2014

IET Image Processing

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Microstimulation is a feasible method targeting visual impairment. In this paper, the authors focus on intra-cortical stimulation to cover the broader spectrum of the issue with the aim of providing a better suited visual aid. They present an overall modular architecture and focus on creating re-usable image processing tools that can be used for image simplification and recognition tasks. One of the main challenges in the image processing path is the real-time restriction; hence they resort to field-programmable gate array (FPGA) hardware acceleration. Herein they demonstrate and describe the architecture of an image feature extractor based on the difference of Gaussians that is at once accurate, generic and low on resources. This architecture also features a Huffman encoding engine that proves useful when resorting to software-hardware (SW-HW) hybrid implementations, and a technique of calibrating and calculating the phosphene map.

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“…Louis‐Xavier Buffoni et al (127) of the Ecole Polytechnique de Montreal (Montreal, Quebec, Canada) reported on the state‐of‐the‐art of multielectrode devices for providing a breakthrough in visual cortical stimulation allowing the blind to recover partial vision. Six image processing strategies that could be used in such a subsystem were presented from the most optimistic that use brightness modulation to emulate grayscale to the most conservative that use only on/off phosphene evocation.…”

Section: Visual Supportmentioning

confidence: 99%

Artificial Organs 2005: A Year in Review

Malchesky¹

2006

Artificial Organs

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Image Processing Strategies Dedicated to Visual Cortical Stimulators: A Survey

Cited by 34 publications

References 17 publications

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Image processing system dedicated to a visual intra‐cortical stimulator

Artificial Organs 2005: A Year in Review

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