04-01-2013, 04:14 PM
A Smart Mobility Solution for Physically Challenged
A Smart Mobility Solution for Physically Challenged.pdf (Size: 1.02 MB / Downloads: 45)
Abstract—
This paper presents a hand gesture and a vision
driven wheelchair system for physically handicapped people. The
system is contrived to have a utilitarian design that caters to
most of the disabilities rather than just one. In order to minimize
system-human interaction, we have endeavored to present two
distinct but closely related concepts viz. the hand gesture and
vision based control system in conjunction for the wheelchair
control. The wheelchair system is designed such that it provides
for a natural and an intuitive user interface which can
comprehend and react to in compliance with the users’
instinctive volition which eases the mobility of the physically
challenged people. All image processing was performed using NI
Vision Assistant. NI LabVIEW was used to train and implement
Neural Networks for Hand Gesture Classification and also to
enable motion control. A prototype was developed on which all
our experiments were successfully carried out. The system has
been tested for users with varied hand shapes and proved to be
extremely reliable.
INTRODUCTION
Old age results in infirmity which eventuates in bodily
enervations. This state in old people often leads to adverse
scenarios where locomotion may pose a major challenge. This
situation is more tragic in the case of the paralyzed and the
quadriplegic [1]. In perspective of these issues, a locomotive
contrivance would serve a monumental purpose, especially
one that comprehends and complies with the users’ will. The
challenge would thus be to devise and construct a locomotive
contraption viz. a wheelchair which accords with the subject’s
instinctive volition and reciprocates in a manner that will
assist navigation.
Various wheelchair systems are found aplenty. Voice
operated devices are by far the most popular. However, voice
operated wheelchairs certainly inhibit the user’s natural ability
to communicate. Moreover, it doesn’t conform to the user’s
instinctive ability to enable locomotion and may prove to be
very difficult to control and maneuver. Numerous attempts
have been made to map eye movements onto a display and to
perform certain tasks by drifting the cursor across various
options available across the terminal. Though successful, this
mode of operations exerts a huge amount of stress on the user
and may make the system impracticable. Certain endeavors
have also been made to develop thought-controlled
wheelchairs.
SYSTEM CONFIGURATION
The conceived architecture of the wheelchair is shown in
fig. 1. The illustration shows the presence of two IEEE-1394,
Monochrome, CMOS cameras for image acquisition. For
capturing hand gestures, a monochrome camera is situated
facing downward as shown. For enabling vision control, eye
movements are captured. This is done by the second
lightweight camera affixed to a band around the forehead,
focused on the eye as outlined. The cameras can be
repositioned based on users’ convenience. The wheelchair
consists of a black colored hand rest. To avoid system
complexity the user is restrained to issue the hand gestures
while placing the hand on the hand rest. Also the hand rest is
black colored to make the background uniform and to
alleviate succeeding complications in image processing.
Besides the cameras, the system consists of an image
processing and a decision-making unit. The image processing
was performed exclusively using LabVIEW RT with Vision
Development Module and decision-making was established
using NI LabVIEW RT with the help of features extracted
from the image-processing unit. The result of the decisionmaking
unit would be signaled as commands to the motors
through the digital I/O module 9472.
Vision Based Control:
Vision based control has been included in our application in
concern of enhancing the scope of the functionalities offered
by the electronic wheelchair. It isn’t hard to notice that eye
movements are far more comfortable than moving any other
part of the body. This simple notion plays a momentous role
in establishing motion control for maneuvering the wheelchair.
Fundamentally, the notion is to afford a system that directs the
subject to the place desired merely by eye movements i.e. the
direction of motion is determined by where the subject is
looking. This rationale can be corroborated by everyday
experience. Whenever a person desires to move to a place in
close proximity, his instinctive reaction would be to look
toward the place before making a move. It is possible to track
the movement of the iris, which is an obvious indicator of the
direction of travel.
SUMMARY AND FUTURE WORK
The paper describes a novel vision and hand gesture based
locomotive system ideal for physically challenged individuals.
The electronic wheelchair also focuses on complying with
user’s instinctive volition enabling much easier mobility. An
eclectic set of 8 hand gestures were selected by statistical
analysis and were used in our experimentations. Our system
excels other systems in that it uses only a minimum number of
gestures and facilitates easy implementations with accurate
results. The system proved to be highly responsive to the user
inputs and behaved precisely in the manner it was
programmed to. We plan to incorporate dynamic, three
dimensional gestures[10] in the future for increased
functionalities .We also plan to incorporate GPS based failure
notification system, which can also be used to monitor the
users’ whereabouts.