Spatial mapping for a visual prosthesis
A visual prosthesis and a method of operating a visual prosthesis are disclosed. Neural stimulation through electrodes is controlled by spatial maps, where a grouped or random association is established between the pixels of the acquired image and the electrodes. In this way distortions from the foveal pit and wiring mistakes in the implant can be corrected. Moreover, broken electrodes can be bypassed and a resolution limit can be tested, together with testing the benefit the patient receives from correct spatial mapping.
1. A method of mapping relationship of pixels of an acquired image to electrodes of a visual prosthesis implant adapted to be positioned on the retina of a subject, the method comprising:
associating a plurality of pixels of the acquired image to form a group of pixels;
associating a plurality of electrodes to form a group of electrodes; and
mapping the group of pixels to the group of electrodes.
2. The method of claim 1 , wherein the group of pixels exhibits an average pixel value, and wherein the mapping of the group of pixels to the group of electrodes results in configuring the visual prosthesis to excite each electrode of the group of electrodes with the average pixel value.
3. The method of claim 1 , wherein the number of pixels in the group of pixels is the same as the number of electrodes in the group of electrodes.
4. The method of claim 1 , wherein the associating the plurality of pixels and the associating the plurality of electrodes are controllable associating operations.
5. The method of claim 1 , wherein a total number of electrodes is 60, arranged in a 6×10 array.
6. A method of undoing perceptual visual distortion in a subject, comprising:
providing the subject with a visual prosthesis, the visual prosthesis configured to acquire images and comprising electrodes positioned on the retina of the subject; and
mapping relationship of pixels of the acquired images to the electrodes in accordance with the method of claim 1 .
7. The method of claim 6 , wherein the group of pixels exhibits an average pixel value, and wherein the mapping of the group of pixels to the group of electrodes results in configuring the visual prosthesis to excite each electrode of the group of electrodes with the average pixel value.
8. The method of claim 6 , wherein the number of pixels in the group of pixels is the same as the number of electrodes in the group of electrodes.
9. The method of claim 6 , wherein the associating the plurality of pixels and the associating the plurality of electrodes are controllable associating operations.
10. A visual prosthesis comprising:
an implanted portion having a radiofrequency receiver and an array of electrodes suitable for stimulating visual neurons; and
an external portion having a video processing unit and including a spatial redirection map, wherein the spatial redirection map establishes a relationship between an image acquired by the visual prosthesis and the array of electrodes, the relationship providing an association between an average pixel value of a plurality of pixels and a subset of the array of electrodes.
11. The visual prosthesis of claim 10 , wherein the plurality of pixels consists of a number of pixels equal to a number of electrodes in the subset of the array of electrodes.
12. The visual prosthesis of claim 10 , wherein multiple associations between average pixel values and subsets of the array of electrodes are provided.
13. A method of mapping relationship of pixels of an acquired image to electrodes of a visual prosthesis implant adapted to be positioned on the retina of a subject, the method comprising:
dividing the acquired image in a plurality of areas,
positioning the electrodes on the retina in a way that a one-to-one spatial relationship between each area and each electrode is implicitly established;
and mapping each area to each pixel in a random one-to-one spatial relationship different from the implicitly established one-to-one spatial relationship.
14. A diagnostic method to determine how a subject's retina is mapped, the diagnostic method comprising the method of claim 13 .
15. A visual prosthesis comprising:
an implanted portion having a radiofrequency receiver and an array of electrodes suitable for stimulating visual neurons; and
an external portion having a video processing unit and including a spatial redirection map, wherein the spatial redirection map establishes a relationship between an image acquired by the visual prosthesis and the array of electrodes, the relationship providing a random association between each pixel value and each electrode of the array of electrodes.
16. The visual prosthesis of claim 15 , wherein the array of electrodes is a 6×10 array of electrodes.