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Binaural sound localizer for azimuthal movement detection based on diffraction.

Kim K, Choi A - Sensors (Basel) (2012)

Bottom Line: The gradient analysis of the ILD between the structured and unstructured microphone demonstrates the rotation directions as clockwise, counter clockwise, and no rotation of the sound source.Acoustic experiments with different types of sound source over a wide range of target movements show that the average true positive and false positive rates are 67% and 16%, respectively.Spectral analysis demonstrates that the low frequency delivers decreased true and false positive rates and the high frequency presents increases of both rates, overall.

View Article: PubMed Central - PubMed

Affiliation: Division of Electronics & Electrical Engineering, Dongguk University-Seoul, Seoul 100-715, Korea. kwkim@dongguk.edu

ABSTRACT
Sound localization can be realized by utilizing the physics of acoustics in various methods. This paper investigates a novel detection architecture for the azimuthal movement of sound source based on the interaural level difference (ILD) between two receivers. One of the microphones in the system is surrounded by barriers of various heights in order to cast the direction dependent diffraction of the incoming signal. The gradient analysis of the ILD between the structured and unstructured microphone demonstrates the rotation directions as clockwise, counter clockwise, and no rotation of the sound source. Acoustic experiments with different types of sound source over a wide range of target movements show that the average true positive and false positive rates are 67% and 16%, respectively. Spectral analysis demonstrates that the low frequency delivers decreased true and false positive rates and the high frequency presents increases of both rates, overall.

No MeSH data available.


Overall RDD system (a) physical configuration and (b) detection algorithm.
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f6-sensors-12-10584: Overall RDD system (a) physical configuration and (b) detection algorithm.

Mentions: Figure 6 demonstrates the overall configuration and algorithm for rotation direction detection. The vertical location of the reference microphone shown in Figure 6(a) provides the equi-radius circle to the circular moving target from both microphones. Without the RDD structure, both signals from bottom and top receiver create the identical level for any circular traces. Only the physical structure of RDD imposes the mutual level difference for rotation detection in the system. The envelope detection in the Figure 6(b) is implemented over the digital domain by squaring followed by the first order infinite impulse response (IIR) filter for low pass filtering. The digital low pass filter via first order IIR structure has low complexity but the pole location of the filter significantly approaches to the unit circle for precise filtering. The coefficient should be selected with care for maintaining stability and RDD system utilizes pole location at 0.9999. In order to estimate the gradient accurately, least square method is exercised based on the first order model as xn = (a × n) + b. The n is the discrete time index and xn is the incoming signal level at the time n. The estimated gradient a and constant value b are obtained by the following equation:(3)(ab)=(RTR)−1RTq,where R=(112131⋮⋮N1),and q=(x1x2x3⋮xN)


Binaural sound localizer for azimuthal movement detection based on diffraction.

Kim K, Choi A - Sensors (Basel) (2012)

Overall RDD system (a) physical configuration and (b) detection algorithm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472845&req=5

f6-sensors-12-10584: Overall RDD system (a) physical configuration and (b) detection algorithm.
Mentions: Figure 6 demonstrates the overall configuration and algorithm for rotation direction detection. The vertical location of the reference microphone shown in Figure 6(a) provides the equi-radius circle to the circular moving target from both microphones. Without the RDD structure, both signals from bottom and top receiver create the identical level for any circular traces. Only the physical structure of RDD imposes the mutual level difference for rotation detection in the system. The envelope detection in the Figure 6(b) is implemented over the digital domain by squaring followed by the first order infinite impulse response (IIR) filter for low pass filtering. The digital low pass filter via first order IIR structure has low complexity but the pole location of the filter significantly approaches to the unit circle for precise filtering. The coefficient should be selected with care for maintaining stability and RDD system utilizes pole location at 0.9999. In order to estimate the gradient accurately, least square method is exercised based on the first order model as xn = (a × n) + b. The n is the discrete time index and xn is the incoming signal level at the time n. The estimated gradient a and constant value b are obtained by the following equation:(3)(ab)=(RTR)−1RTq,where R=(112131⋮⋮N1),and q=(x1x2x3⋮xN)

Bottom Line: The gradient analysis of the ILD between the structured and unstructured microphone demonstrates the rotation directions as clockwise, counter clockwise, and no rotation of the sound source.Acoustic experiments with different types of sound source over a wide range of target movements show that the average true positive and false positive rates are 67% and 16%, respectively.Spectral analysis demonstrates that the low frequency delivers decreased true and false positive rates and the high frequency presents increases of both rates, overall.

View Article: PubMed Central - PubMed

Affiliation: Division of Electronics & Electrical Engineering, Dongguk University-Seoul, Seoul 100-715, Korea. kwkim@dongguk.edu

ABSTRACT
Sound localization can be realized by utilizing the physics of acoustics in various methods. This paper investigates a novel detection architecture for the azimuthal movement of sound source based on the interaural level difference (ILD) between two receivers. One of the microphones in the system is surrounded by barriers of various heights in order to cast the direction dependent diffraction of the incoming signal. The gradient analysis of the ILD between the structured and unstructured microphone demonstrates the rotation directions as clockwise, counter clockwise, and no rotation of the sound source. Acoustic experiments with different types of sound source over a wide range of target movements show that the average true positive and false positive rates are 67% and 16%, respectively. Spectral analysis demonstrates that the low frequency delivers decreased true and false positive rates and the high frequency presents increases of both rates, overall.

No MeSH data available.