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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.


Disparity level between the RDD and reference signal for constant distance (left), withdrawing (middle), and approaching (right) target. The above and below figure are for CW and CCW direction respectively.
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f12-sensors-12-10584: Disparity level between the RDD and reference signal for constant distance (left), withdrawing (middle), and approaching (right) target. The above and below figure are for CW and CCW direction respectively.

Mentions: According to the experimental configuration described above, the disparity levels between the RDD and reference signal are generated for the selected movement situations in Figure 12. It should be noted that the signal is processed with the envelope detector; therefore, the high frequency component is reduced for corresponding to the approximate signal level. The rotation of CW direction increases the DoA angle, which relates to the higher barrier height; hence, the disparity level tends to have a negative gradient as shown in the first row of figures. The CCW direction is demonstrated at the second row figures with positive gradient due to the lower barrier height for the further rotation. All depicted figures represent the correct rotation direction given by the acoustic signal in the distinctive radial movement. The left column delivers the situation of the equi-radius angular movement. The middle and right column provide the condition of the radial movement for the withdrawing and approaching source respectively. The overshoot and undershoot in the figures are caused by the signal level transition and IIR filter since the filter in the envelope detector has extended convergence time for the input signal change. Note that no significant shoots are observed at the left column situation because of the steady input level from equi-distance movement.


Binaural sound localizer for azimuthal movement detection based on diffraction.

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

Disparity level between the RDD and reference signal for constant distance (left), withdrawing (middle), and approaching (right) target. The above and below figure are for CW and CCW direction respectively.
© Copyright Policy
Related In: Results  -  Collection

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

f12-sensors-12-10584: Disparity level between the RDD and reference signal for constant distance (left), withdrawing (middle), and approaching (right) target. The above and below figure are for CW and CCW direction respectively.
Mentions: According to the experimental configuration described above, the disparity levels between the RDD and reference signal are generated for the selected movement situations in Figure 12. It should be noted that the signal is processed with the envelope detector; therefore, the high frequency component is reduced for corresponding to the approximate signal level. The rotation of CW direction increases the DoA angle, which relates to the higher barrier height; hence, the disparity level tends to have a negative gradient as shown in the first row of figures. The CCW direction is demonstrated at the second row figures with positive gradient due to the lower barrier height for the further rotation. All depicted figures represent the correct rotation direction given by the acoustic signal in the distinctive radial movement. The left column delivers the situation of the equi-radius angular movement. The middle and right column provide the condition of the radial movement for the withdrawing and approaching source respectively. The overshoot and undershoot in the figures are caused by the signal level transition and IIR filter since the filter in the envelope detector has extended convergence time for the input signal change. Note that no significant shoots are observed at the left column situation because of the steady input level from equi-distance movement.

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.