Artificial Perceptual Sensors - Artificial Human Sensors: Science and Applications - page 134

Figure 6.4. The degenerated perception ability in a traffic situation at dawn when it is
raining. Photo courtesy and copyright Peter Wide c 2010.
sequence process. It has been estimated that the fastest speed to process divided
attention without errors may be as low as two rapid and sequential targets per sec-
ond, Glass (1986). If a person's vision system is able to update the visual scene at
that speed, everyone may calculate the driver's capability between every update,
i.e., the distance the car moves between two visual updates. Furthermore, if there
is an aged driver, the calculated distance will most likely exhibit a larger value.
The second example illustrates the complement to the human vision by an
artificial night sensitive system. Lately, night vision systems have been of interest
to the car manufacturer. A night vision system built in the front of a car may
indicate to the driver that the car is out of its driving path or that an obstacle in
form of an animal or a human may be in the collision direction with the car. The
effectiveness is as always a communication issue, indicating the need of adapting
to the human user's perception ability. When driving the car in high speed, the
warning system indeed need to communicate a possible danger to the driver in an
effective manner that is adapted to human capability.
6.2.3 Tactile-Based Physical Sensors
Artificial tactile-based sensing development has emphasised on finding physical
object shapes and contact forces. However, there are other tactile functions that
are of important features, in for example an artificial hand concept. Tactile texture
recognition is an essential function that refers to the qualities of the physical object
surface. The knowledge about surface and surface texture, temperature and fric-
tions are important properties for estimating an object and to recognise its physical
properties. When a person moves her fingers across the surface of an object, the
complex feeling apart from its shape and (a)symmetry is by tactile-based sensing
recognised as the person's perceptual experience of the object's texture. The haptic