YouTube - Extraordinary People - The boy who sees without eyes [1/5]
(5 part series)
A boy who lost his eyes to cancer uses his hearing to "see" what's around him...pretty amazing.
"This is a documentary about a boy (Ben Underwood) who has taught himself to use echo location to navigate around the world. Ben Underwood is blind, but has managed to do some truly extraordinary feats"
his website:
Ben Underwood
Echolocation: What is it anyway?
"Human echolocation is the ability of humans to sense objects in their environment by hearing echoes from those objects. This ability is used by some blind people to navigate within their environment. They actively create sounds, such as by tapping their canes or by making clicking noises with their mouths. Human echolocation is similar in principle to active sonar and to the animal echolocation employed by some animals, including bats and dolphins.
By interpreting the sound waves reflected by nearby objects, a person trained to navigate by echolocation can identify the location and sometimes size of nearby objects, and use this information to steer around obstacles and travel from place to place. However, since humans make sounds with much lower frequencies and slower rates, human echolocation can only picture comparatively much larger objects than other echolocating animals."
Extraordinary People - The boy who sees without eyes
