Page 43 - Concise Encyclopedia of Robotics

Binaural Machine Hearing
desired key is larger than half the highest number in the list,then the second
half of the list is accepted, and the first half is rejected. The process is
repeated, each time selecting half of the list and rejecting the other half,
until only one item remains. This item is the desired key.
item from a list of 21. Keys are indicated by filled-in squares, except for the
desired key, 21, which is indicated by a shaded circle. “Dummy” keys are
shown as open squares. Compare BIASED SEARCH.
1. The illustration shows an example of a binary search to choose one
2.
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4.

5.

6.
Binary search

BINAURAL MACHINE HEARING
Binaural machine hearing utilizes two sound transducers, spaced a certain
minimum distance from each other, to determine the direction from which
acoustic waves are coming. This is done by comparing the relative phase
and/or the relative loudness of the incoming wavefronts at the transducers.
The human ear/brain system processes acoustic information to a high
degree of exactitude, allowing a person to locate a sound source with
remarkable accuracy even when the source cannot be seen. When
equipped with sensitive transducers, a circuit called a phase comparator,
and a sophisticated controller, a robot can do the same.
In binaural machine hearing, two sound transducers are positioned
on either side of a robot’s “head.” The phase comparator measures the
relative phase and intensity of the signals from the two transducers.
These data are sent to the controller, letting the robot determine, with

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