Usually when we talk about location-based applications we count on our ability to see in order to benefit from their use. But what if you can’t see? Blind psychologist Daniel Kish describes his experience with “echolocation”, a way of interpreting echoes to learn something about the location of nearby objects.
Echoes can be used to perceive three characteristics of objects: where they are, their general size and shape and, to some extent, what they are like – solid versus sparse, sound-reflective versus sound-absorbent. This allows the brain to create an image of the environment.
For example, I perceive a parked car as a large object that starts out low at one end, rises in the middle and drops off again. The difference in the height and slope pitch at either end helps me identify the front from the back end; typically, the front will be lower, with a more gradual slope up to the roof.
Distinguishing between types of vehicles is also possible. A pickup truck, for instance, is usually taller, with a hollow sound reflecting from its bed. An SUV is usually taller and sounds blockier.
A tree has narrow and solid characteristics at the bottom – the trunk – broadening and becoming more sparse towards the top. More specific characteristics, such as the size, leafiness or height of the branches, can also be determined.
