Artificial Perceptual Sensors - Artificial Human Sensors: Science and Applications - page 148

6.4.2 Human Aid Applications
Visually impaired people have for their mobility, as tradition, been using walk-
ing sticks to detect obstacles. Despite more or less highly and complex technology
solutions that are often available, still the currently most common method of range
detection used by the blind is the traditional walking stick, that exhibits an effec-
tive interaction with the individual. The limitation of the walking stick is that a
blind person must come into close proximity with its surroundings to determine
the location of an obstacle. The development of technology aid is, despite their
limitations, available to assist the blind person in moving and travelling situa-
tions, i.e., an electronic travel aid. The techniques, as described earlier also use
electronic sticks that are normally ultrasound, radio frequency signals or laser to
detect obstacles at a generally longer distance than the traditional stick. However,
the effectiveness of the interface between a user and the system may raise some
fundamental questions concerning the perceptual limitation.
As noticed, the interface between the sensor system and the individual needs
to be of high importance. The interfacing device also needs to be fast and should
exhibit a natural additional moment to the human perception. The intelligence
of the systems available on the market is, however, moderately limited in terms
of interacting with a user. For example, when producing a varying frequency of
chirps (sound), vibration or pressure that is inversely proportional to the distance
measured. The user often lacks additional information, i.e., if a moving object is
interfering with an unexpected behaviour that may affect the users information
path about the object, for example, a crossing dog. In the literature also, sensors
mounted on a lightweight helmet have been found, which allow the user to obtain
a reading in whichever direction the head points. This solution may not be best
suited for the user, due to its inconvenient cap that most likely affects the flexibility.
The portable power source and corresponding electronic circuit in using elec-
tronic aid are often encased in a box and attached to the user's belt or fixed to the
stick. The obstacle avoidance warnings are focussed on single objects and may be
indicatory on distance of up to 1.5 m (12 feet), which also is a challenge for the user
to master in a complex dynamic environment, Lopes (2001).
6.4.3 Human Substituting Perceptual and Interaction System
The beneficial use of artificial sensor capability is generally considered to be its
ability to perform in a superior manner, when the desire in certain demanding
situations may be to measure human-related properties in complicated or haz-
ardous situations. The typical use of these sensors are in tasks where the human
senses may not perform the very best. For example, a quality measuring operator
who is frequently smelling and tasting jam in a production unit may exhibit a pas-
sive perception attitude and experience a mood of blase which may result in a not
optimal process of sensing.
The canary in a cage placed in a mine is perhaps the most illustrative example
of biological supportive sensor systems that since years ago have protected the