10-10-2014, 12:14 PM
Retina Based Mouse Control
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Abstract
—The paper presents a novel idea to control computer
mouse cursor movement with human eyes. In this paper, 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
INTRODUCTION
EOPLE with physical disabilities face a lot of problems in
communication with their fellow human beings. In this
paper, the design of an eye-controlled mouse system with an
emphasis on the Human-Computer-Interface (HCI) based on
Electro-oculography (EOG) has been presented. Computers
can be used by persons with disabilities for communication,
environmental control, source of information and
entertainment.
There are a lot of head and eye movement tracking systems
for cursor control. Some of them are equipped with
sophisticatedly designed systems using complicated concepts
or using high quality devices such as high cost 3-D graphical
hardware [1
Sensing Eye Signals
Due to the higher metabolic rate at the retina compared to
the cornea, the eye maintains a voltage of +0.40 to +1.0
millivolts with respect to the retina. This corneoretinal
potential, which is roughly aligned with the optic axis and
hence rotates with the direction of gaze, can be measured by
surface electrodes placed on the skin around the eyes, (see
Fig. 2). The actual recorded potentials are smaller in the range
of 15 to 200 microvolts and are usually amplified before
processing [4]. With proper calibration, the orientation of the
electric dipole can be used to specify the angular position of
the eyeball to within 2 degrees vertically and 1.5 degrees
horizontally [4]–[5]
Discussions
When eyes move in continuous vertical fashion, the
variations in the output can be seen accordingly (see Fig. 9).
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.
Some variations are also detected in the output when eyes
are still (see Fig. 10). The reason is that the eyes still do some
movements known as stabilizing movements to remain
focusing the image onto the retina when at rest. This portion
can be neglected by implementing a software based Band
Reject filter. The white doted lines in the figure 10 show the
range of this filter.
CONCLUSION AND FUTURE DIRECTIONS
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.
A. Future Directions
Human Computer Interfaces have an enormous scope in
near future. There are four aspects as far as future
enhancements are concerned.
• Making a model that can do clicking as well. By
clicking, the user can search directories, write notes
and browse internet pages etc.
• Making of Sophisticated Software by which one can
paint, chat and play virtual games.
• Use of other areas of scalp for EOG acquisition.
• Make a sophisticated product that can be
implemented in fighter jets. Pilot just has to point the
target with the eyes and press the trigger when target