VISUAL PROSTHESIS
By Richard Jones and David Henley
OVERVIEW
Various methods of helping (partially) blind– Brain implant– Seeing with sound– Eye implant
The First Useful Artificial Eye
First implanted in 1978 Allowed ‘Jerry’ to see shades
of grey– Whilst connected to a 10ft
by 7ft, 2 ton computer Now computer weighs 5kg,
and Jerry sees phosphenes
Edge detection algorithms applied to images from camera ‘Jerry’ can navigate New York subway Very limited field of view
Neural Implants
Camera mounted on glasses Computer converts signals
into a form that can be ‘understood’ by the brain
Signal passes down wires into the skull
Connect to an electrode array on the surface of the visual cortex.
Since the 1950s it has been known that stimulating the visual cortex produces phosphenes
The Second Generation
Costs $80,000 US Percutaneous pedestals
- were sunk into both sides of Jens skull
Connected to platinum electronic arrays lying on surface of visual cortex
Phosphene images had to be mapped He drove a car
Alternative methods
Implant described sits on top of the visual cortex– Many neurons are stimulated at once
Richard Normann, is working on device that will be implant into the visual cortex– Lower voltages required, so safer– Much more accurate
Potential to stimulate individual neurons
vOICe DEVICE
Visual Cortex can be stimulated by sound Typically 4000 pixels (vocals) / sec Perception 1000-4000 $2500 (exc training/adaptation) Environment /web etc
HOW IT WORKS
1) Left and Right– Scanning, stereo
2) Top and Bottom– Pitch = elevation
3) Dark and Light– Loudness = brightness
EXAMPLE
Oscilloscope other sound?
EXAMPLE 2
USER THOUGHTS
A late-blinded user of The vOICe commented on August 29, 2002, saying: ``Just sound?.... No, It is by far more, it is sight ! There IS true light perception generated by the vOICe. When I am not wearing the voice the light I perceive from a small slit in my left eye is a grey fog. When wearing the vOICe the image is light with all the little greys and blacks. Yet a definite light image .” …….
ADVANTAGES
Cheap (1/10 implant cost) Fewer risks Quick No implants, no electrodes, no surgery Unobtrusive
DISADVANTAGES
Cannot hear anything else Limited information Brain can only perceive so much sound Training is equivalent to learning a foreign
language
EYE IMPLANT
Artificial Retina Optic nerves and ganglia are intact Partially sighted Infra-red positioning/info/power
EYE IMPLANT
EYE IMPLANT
EXAMPLE OF PIXELATION
CONCLUSON
Field is advancing all the time Three routes mentioned here have adv/disadv Dr. Dobelle has predicted that guide dogs /
Braille will be obsolete by 2100 Geordi LaForge here we come!!!