Fitting of Brightness as a Function of Current Amplitude in a Visual Prosthesis

摘要

To accurately represent a visual scene a visual prosthesis must convey luminance information across a range of brightness levels. To do this, the brightness of phosphenes produced by an individual electrode should scale appropriately with luminance, and the same luminance should produce equivalently bright phosphenes across the entire electrode array. Given that the function relating current to brightness varies across electrodes, it is necessary to develop a fitting procedure that will permit brightness to be equated across an entire array.;The current invention describes a method of performing a brightness fitting that normalizes brightness across electrodes. The method determines a set of parameters that are stored in the subjects Video Configuration File—the look-up table that converts the video camera input to stimulation profiles for each electrode. One electrode would be specified as the standard. Brightness rating would be carried out on that electrode so “rating” as a function of current amplitude was known for that electrode.

主权项

1. A visual prosthesis, comprising:
an array of electrodes suitable to be placed in proximity to visual neural tissue; a camera for receiving a visual scene; and a control device coupling said camera to said array of electrodes including a neural stimulator for applying a plurality of stimuli visual neural tissue; means for measuring brightness responses to said stimuli on a first one of said array of electrodes; means for deriving a first formula comprising a stimulation curve estimating brightness levels not tested based upon said brightness responses to said stimuli on said first one of said array of electrodes; means for measuring brightness responses to said stimuli on a second one of said array of electrodes; means for deriving a second formula comprising a stimulation curve estimating brightness levels not tested based upon brightness response to said stimuli on said second one of said electrodes and said first formula; and means for generating stimuli by applying said first formula and said second formula to visual input from said camera.