Objection detection by robot using sound localization and sound based object classification bayesian network
An object detection system includes at least one sound receiving element, a processing unit, a storage element and a sound database. The sound receiving element receives sound waves emitted from an object. The sound receiving element transforms the sound waves into a signal. The processing unit receives the signal from the sound receiving unit. The sound database is stored in the storage element. The sound database includes a plurality of sound types and a plurality of attributes associated with each sound type. Each attribute has a predefined value. Each sound type is associated with each attribute in accordance with Bayesian's rule, such that a conditional probability of each sound type is defined for an occurrence of each attribute.
1 . An object detection system for use with a robot, said object detection system comprising:
at least one sound receiving element for receiving sound waves emitted from an object, said at least one sound receiving element transforming said sound waves into a signal;
a processing unit for receiving said signal from said sound receiving unit;
a storage element; and
a sound database stored in said storage element, said sound database includes a plurality of sound types and a plurality of attributes associated with each sound type, each attribute having a predefined value, each sound type being associated with each attribute in accordance with Bayesian's rule, such that a conditional probability of each sound type is defined for an occurrence of each attribute.
2 . The object detection system as set forth in claim 1 , wherein said sound types are arranged as parental nodes within said Bayesian network.
3 . The object detection system as set forth in claim 2 , wherein said attributes are arranged as child nodes with respect to said parental nodes within said Bayesian network.
4 . The object detection system as set forth in claim 1 , wherein said attributes are selected from the group consisting of: histogram features, linear predictive coding, cepstral coefficients, short-time Fourier transform, timbre, zero-crossing rate, short-time energy, root-mean-square energy, high/low feature value ratio, spectrum centroid, spectrum spread and spectral rolloff frequency.
5 . A method of identifying objects using sound emitted by the objects, the method comprising the steps of:
providing a sound database which includes a plurality of sound types and a plurality of attributes associated with each sound type, wherein each attribute has a predefined value, and wherein each sound type is associated with each attribute in accordance with Bayesian's rule, such that a conditional probability of each sound type is defined for an occurrence of each attribute;
forming a sound input based on sound emitted from the object;
applying a filter to the sound input to facilitate extraction of spectral attributes that correspond with the attributes of the sound database;
extracting the spectral attributes;
comparing the spectral attributes of the sound input with the predetermined attributes of the sound database; and
selecting the sound type having attributes with the highest similarity to the spectral attributes of the sound input.
6 . The method as set forth in claim 5 , wherein the plurality of attributes for each sound type is selected from the group consisting of: histogram features, linear predictive coding, cepstral coefficients, short-time Fourier transform, timbre, zero-crossing rate, short-time energy, root-mean-square energy, high/low feature value ratio, spectrum centroid, spectrum spread and spectral rolloff frequency.
7 . The method as set forth in claim 5 , wherein the step of localizing the sound input includes computation of a Fourier transform based on the sound input.
8 . The method as set forth in claim 5 , wherein the step of localizing the sound input includes determining a directional component at each frequency band of the sound input.
9 . The method as set forth in claim 5 , wherein the step of localizing the sound input includes a clustering frequencies having substantially the same directional component.
10 . The method as set forth in claim 5 , wherein the step of localizing the sound input includes forming a pair of sound signals based on the sound emitted from the object.
11 . The method as set forth in claim 10 , wherein the step of localizing the sound input includes measuring a period of time elapsed between the formations of the sound signals to define an interaural time difference.
12 . The method as set forth in claim 11 , wherein the step of localizing the sound input includes measuring and determining a difference in amplitude between the sound signals to define an interaural level difference.
13 . The method as set forth in claim 12 , wherein the step of localizing the sound input includes estimating azimuth based on a combination of the interaural time and level differences.
14 . A method of training a Bayesian network classifier, said method comprising the steps of:
providing the network with a plurality of sound types;
providing the network with a plurality of attributes, wherein each attribute has a predefined value;
defining a conditional probability for each attribute given an occurrence of each sound type; and
classifying the sound types in accordance with Bayesian's rule, such that the probability of each sound type given a particular instance of an attribute is defined.
15 . The method as set forth in claim 14 , wherein the plurality of attributes for each sound type is selected from the group consisting of: histogram features, linear predictive coding, cepstral coefficients, short-time Fourier transform, timbre, zero-crossing rate, short-time energy, root-mean-square energy, high/low feature value ratio, spectrum centroid, spectrum spread and spectral rolloff frequency.