The retina is a thin layer of neural tissue that lines the back wall inside
the eye. Some of these cells act to receive light, while others interpret the
information and send messages to the brain through the optic nerve. This is part
of the process that enables us to see. In damaged or dysfunctional retina, the
photoreceptors stop working, causing blindness. By some estimates, there are more
than 10 million people worldwide affected by retinal diseases that lead to loss
absence of effective therapeutic remedies for retinitis pigmentosa (RP) and age-related
macular degeneration (AMD) has motivated the development of experimental strategies
to restore some degree of visual function to affected patients. Because the remaining
retinal layers are anatomically spared, several approaches have been designed
to artificially activate this residual retina and thereby the visual system.
present, two general strategies have been pursued. The "Epiretinal"
approach involves a semiconductor-based device placed above the retina, close
to or in contact with the nerve fiber layer retinal ganglion cells. The information
in this approach must be captured by a camera system before transmitting data
and energy to the implant. The "Sub retinal" approach involves the electrical
stimulation of the inner retina from the sub retinal space by implantation of
a semiconductor-based micro photodiode array (MPA) into this location. The concept
of the sub retinal approach is that electrical charge generated by the MPA in
response to a light stimulus may be used to artificially alter the membrane potential
of neurons in the remaining retinal layers in a manner to produce formed images.
Some researchers have developed an implant system where a video camera captures
images, a chip processes the images, and an electrode array transmits the images
to the brain. It's called Cortical Implants.
The human visual system is remarkable instrument.
It features two mobile acquisition units each has formidable preprocessing circuitry
placed at a remote location from the central processing system (brain). Its primary
task include transmitting images with a viewing angle of at least 140deg and resolution
of 1 arc min over a limited capacity carrier, the million or so fibers in each
optic nerve through these fibers the signals are passed to the so called higher
visual cortex of the brain
nerve system can achieve this type of high volume data transfer by confining such
capability to just part of the retina surface, whereas the center of the retina
has a 1:1 ration between the photoreceptors and the transmitting elements, the
far periphery has a ratio of 300:1. This results in gradual shift in resolution
and other system parameters.
At the brain's highest level the visual cortex
an impressive array of feature extraction mechanisms can rapidly adjust the eye's
position to sudden movements in the peripherals filed of objects too small to
se when stationary. The visual system can resolve spatial depth differences by
combining signals from both eyes with a precision less than one tenth the size
of a single photoreceptor.
You may also like this : Bio Battery, Paper Battery , Smart Antenna, Mobile Train Radio Communication, Hydrogen Super Highway , Humanoids Robotics, Optical Ethernet , Transparent Electronics , Thermography , Surface Plasmon Resonance , Microwave Superconductivity , Memristor , Earthing transformers For Power systems, Direct Current Machines , DD Using Bio-robotics , Wireless LAN Security , Smart Note Taker , Clos Architecture in OPS, 4G Wireless Systems , Wearable Bio-Sensors , Poly Fuse , Non Visible Imaging , Nuclear Batteries-Daintiest Dynamos , MILSTD 1553B , Micro Electronic Pill , MOBILE IPv6 , Chip Morphing , Challenges in the Migration to 4G, CAN , BIT for Intelligent system design, A 64 Point Fourier Transform Chip , Anthropomorphic Robot hand: Gifu Hand II , ANN for misuse detection, Adaptive Optics in Ground Based Telescopes , Aluminum Electrolytic Capacitors , IBOC Technology , Honeypots , Immersion Lithography , Grating Light Valve Display Technology , Fractal Antennas , HART Communication ,E-Textiles, Electro Dynamic Tether , FPGA in Space , DV Libraries and the Internet , Co-operative cache based data access in ad hoc networks , Mesh Topology , Mesh Radio, Metamorphic Robots, Low Energy Efficient Wireless Communication Network Design,Electronics Seminar Reports, PPT and PDF.
Labels : ECE Seminar Topics List, ECE Seminar Topics 2009|2010|2011|2012, ECE Paper Presentations, B Tech ECE Seminar Topics, ECE Seminar Topics Free Download, Electronics Seminar Topics List, List Seminar Topics Electronics, Seminar Topics for Electronics and Communication 2009|2010|2011|2012, IEEE Seminar Topics Electronics Communication 2009|2010|2011|2012, Seminar Topics Electronics Communication Engineering, Latest Seminar Topics Electronics Communication 2009|2010|2011|2012, IEEE, Electronics for You, Electronics Seminar Topics PDF, Electronics Seminar Topics 2009|2010|2011|2012, Electronics Seminar Topics Technical Seminars