Patent ID: 7284255

Claim:
A method for correlating a first packet of feature waveforms from an unknown source with a second packet of feature waveforms from a known broadcast audio source in order to associate a known broadcast audio source with the first packet of feature waveforms, comprising the steps of: (A) receiving free field audio signals using a microphone that is included in a portable data collection unit, wherein the free field audio signals are audible to a user proximate the portable data collection unit, and generating the first packet of feature waveforms in accordance with said free field audio signals received by the microphone; and determining, with at least one processor, at least first, second and third correlation values (cv 1 , cv 2 , cv 3 ) by correlating features from the first and second packets, wherein the first correlation value (cv 1 ) is determined by correlating features associated with a first frequency band from the first and second packets, the second correlation value (cv 2 ) is determined by correlating features associated with a second frequency band from the first and second packets, and the third correlation value (cv 3 ) is determined by correlating features associated with a third frequency band from the first and second packets; (B) computing, with said at least one processor, a first weighting value in accordance with the features from the second packet associated with the first frequency band, a second weighting value in accordance with the features from the second packet associated with the second frequency band, and a third weighting value in accordance with the features from second packet associated with the third frequency band; (C) computing, with said at least one processor, a weighted Euclidean distance value (D w ) representative of differences between the first and second packets from the first, second and third correlation values and the first, second and third weighting values; wherein the first weighting value corresponds to a standard deviation (std 1 ) of the features from the second packet associated with the first frequency band, the second weighting value corresponds to a standard deviation (std 2 ) of the features from the second packet associated with the second frequency band, and the third weighting value corresponds to a standard deviation (std 3 ) of the features from the second packet associated with the third frequency band; wherein the weighted Euclidean distance value (D w ) is determined in accordance with the following equation: D w =[((std 1 )*(1− cv 1 )) 2 +((std 2 )*(1 −cv 2 )) 2 +((std 3 )*(1 −cv 3 )) 2 ] 1/2 /[(std 1 ) 2 +std 2 ) 2 +(std 3 ) 2 ] 1/2 ; and (D) determining, with said at least one processor and in accordance with the weighted Euclidean distance value (D w ), whether the first packet derived from the free field audio signals received by the microphone in the portable data collection unit is associated with the known broadcast audio source.