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BABA GHULAM SHAH BADSHAH UNIVERSITY COLLEGE OF ENGINEERING AND TECHNOLOGY SEMINAR PRESENTATION |
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RETINA BASED MOUSE CONTROL By:
SAHIL KUMAR SAREEN
04-ITE-07
B.TECH ITE 6TH SEMISTER |
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Facial positioning of electrodes Techniques Block Diagram Introduction RETINA BASED MOUSE CONTROL Implementation Result Conclusion |
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INTRODUCTION The concept presents a novel idea to control computer
mouse cursor movement with human eyes. In this topic, a working
of the product has been described as to how it helps the special
people share their knowledge with the world. Number of traditional
techniques such as Head and Eye Movement Tracking Systems etc.
exist for cursor control by making use of image processing in which
light is the primary source. Electro-oculography (EOG) is a new
technology to sense eye signals with which the mouse cursor can be
controlled. The signals captured using sensors, are first amplified,
then noise is removed and then digitized, before being transferred to
PC for software interfacing. |
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FACIAL POSITIONING OF ELCCTODES |
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TECHNIQUES HEAD MOVEMENT TRECKING SYSTEM
EYE TRACKING
ELECTRO-OCULOGRAPHY (EOG)
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HEAD MOVEMENT TRACKING SYSTEM Head Movement Tracking System is a device that transmits
a signal from top of the computer monitor and tracks a
reflector spot placed on the user's forehead or eyeglasses.
Using only the movement of the user’s head, the movement of the cursor can be controlled, allowing ‘The Head Mouse’ to be used as an ordinary computer mouse . |
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Eye tracking is a technology in which a camera or imaging
system visually tracks some features of the eye and then a
computer determines where the user is looking at .
Eye tracking technology can be divided into two areas;
firstly a remote computer-mounted device, in which an IR camera is mounted on a computer screen, secondly a head-mounted device, in which an IR camera is placed on user’s head. This technique is accurate but expensive. Eye tracking |
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Electro-oculography (EOG) is a new technology of placing electrodes on user’s forehead around the eyes to record eye movements. EOG is a very small electrical potential that can be detected using electrodes. The majority of the people using
this setup may have severe cerebral palsy or been born with a congenital brain disorder or suffered traumatic brain injury, for example from automobile or drowning accidents. This
technique is adapted because it is inexpensive and accurate EOG |
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IMPLEMENTATION .
A). Sensing Eye Signals
Due to the higher metabolic rate at the retina compared to the eye maintains a voltage of +0.40 to +1.0 millivolts with respect to the retina.
The potential is about 15-200 micro volts .
To detect vertical motion one electrode is 2cm above and one is 1cm below the left eye.
To detect horizontal motion an electrode is placed outer side of each eye.
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B). Signal Amplification
Devices considered for signal amplification are A0401 instrumentation amplifier with built-in filters , Eye Sense EOG amplifier, RHA1016, CED1902 etc.
All these devices were very expensive.
Common mode signals present in instrumentation filter’s input are greatly reduced by amplifiers common moDe rejection.
To remove interference and electro-static discharge a RC low pass filter is used. |
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C). Driven-Right Leg
IN126P’s Common Mode Rejection Ratio (CMRR) is
around 94DB.
To improve it, a Drive-Right Leg circuit is implemented.
The circuit reads noise and transfers a minute signal back to the body through electrode to reduce its effect.
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D). Q-Notch Filter
A simple q notch is used to reduce power line noise and interference due to nearby electrical equipments.
It reduce the fluctuation when it is set to 60Hz cutoff
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E). High Pass Filter
A high pass filter is used to reject the dc generated by the potential difference between the reference electrode and active electrodes.
DC potential is due to skin impedance and can be highly variable, due to skin temperature, skin moisture, humidity, day time etc.
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F). Anti-Aliasing Filter
Aliasing occurs when the input signal frequency is greater then ½ of sampling frequency.
The sample frequency achieved through custom software is 100Hz.
Since power line noise frequency > 1/2 sampling frequency.
Therefore no Anti-Aliasing filter is required.
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H). Software Interfacing
The software has been written down in Visual C++
environment.
2. It will receive digital information from two
parallel ports, one after the other and then that
information would be mapped onto a real-time graph.
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RESULT A Brief Discussions
When eyes move in continuous vertical fashion, the
variations in the output can be seen accordingly.
Because of the positive and negative nature of the
instrumentation amplifier’s input channel, higher value is
achieved when eyes move upward and lower value is achieved
when eyes move downward. Similar would be the case for
right-left movement.
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CONCLUSION A human computer interface with basic functionality is
successfully implemented and demonstrated. The final
application consisted of:
• An eye controlled cursor providing control over left,
right, up and down.
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