Improving Power Spectra Estimation in 2-Dimensional Areas Using Number of Active Sound Sources

2011 ◽  
Vol E94-A (1) ◽  
pp. 273-281 ◽  
Author(s):  
Yusuke HIOKA ◽  
Ken'ichi FURUYA ◽  
Yoichi HANEDA ◽  
Akitoshi KATAOKA
Keyword(s):  
Power Spectra ◽  
Sound Sources

scholarly journals The role of spectral composition of sounds on the localization of sound sources by cats

2013 ◽  
Vol 109 (6) ◽  
pp. 1658-1668 ◽  
Author(s):  
Daniel J. Tollin ◽  
Janet L. Ruhland ◽  
Tom C. T. Yin
Keyword(s):  
Sound Localization ◽  
Spectral Composition ◽  
Power Spectra ◽  
Sound Sources ◽  
Gaze Shift ◽  
Localization Accuracy ◽  
Low Pass ◽  
Localization Performance ◽  
High Pass

Sound localization along the azimuthal dimension depends on interaural time and level disparities, whereas localization in elevation depends on broadband power spectra resulting from the filtering properties of the head and pinnae. We trained cats with their heads unrestrained, using operant conditioning to indicate the apparent locations of sounds via gaze shift. Targets consisted of broadband (BB), high-pass (HP), or low-pass (LP) noise, tones from 0.5 to 14 kHz, and 1/6 octave narrow-band (NB) noise with center frequencies ranging from 6 to 16 kHz. For each sound type, localization performance was summarized by the slope of the regression relating actual gaze shift to desired gaze shift. Overall localization accuracy for BB noise was comparable in azimuth and in elevation but was markedly better in azimuth than in elevation for sounds with limited spectra. Gaze shifts to targets in azimuth were most accurate to BB, less accurate for HP, LP, and NB sounds, and considerably less accurate for tones. In elevation, cats were most accurate in localizing BB, somewhat less accurate to HP, and less yet to LP noise (although still with slopes ∼0.60), but they localized NB noise much worse and were unable to localize tones. Deterioration of localization as bandwidth narrows is consistent with the hypothesis that spectral information is critical for sound localization in elevation. For NB noise or tones in elevation, unlike humans, most cats did not have unique responses at different frequencies, and some appeared to respond with a “default” location at all frequencies.

Spectral Cues Explain Illusory Elevation Effects With Stereo Sounds in Cats

2003 ◽  
Vol 90 (1) ◽  
pp. 525-530 ◽  
Author(s):  
Daniel J. Tollin ◽  
Tom C.T. Yin
Keyword(s):  
Direct Evidence ◽  
Power Spectra ◽  
Spectral Shape ◽  
Precedence Effect ◽  
Time Of Arrival ◽  
Exact Form ◽  
Sound Sources ◽  
Spectral Cues ◽  
Interaural Differences ◽  
High Elevations

Mammals localize sound sources in azimuth based on two binaural cues, interaural differences in the time of arrival and level of the sounds at the ears. In contrast, the cue for elevation is based on patterns of the broadband power spectra at each ear that result from the direction-dependent acoustic filtering properties of the head and pinnae. Although the exact form of this “spectral shape” cue is unknown, most attention has been directed toward a prominent direction-dependent energy minimum, or “notch,” because its location in frequency, for both humans and cats, moves predictably from low to high as a source is moved from low to high elevations. However, there is little direct evidence that these spectral notches are important elevational cues in animals other than humans. Here we demonstrate a striking illusion in the localization of sounds in elevation by cats using stimulus configurations that elicit summing localization and the precedence effect that can be explained by spectral shape cues.

Image formation analysis of thick biological specimens using three-dimensional power-spectra of through focus series

1994 ◽  
Vol 52 ◽  
pp. 124-125
Author(s):  
Karen F. Han
Keyword(s):  
Inelastic Scattering ◽  
Imaging Techniques ◽  
Mass Density ◽  
Relative Proportion ◽  
Three Dimensional ◽  
Power Spectra ◽  
Image Formation ◽  
Energy Filtering ◽  
Ewald Sphere ◽  
Nonlinear Imaging

The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.

Log-log scale roughness spectroscopy of surfaces

1993 ◽  
Vol 51 ◽  
pp. 224-225
Author(s):  
P. Fraundorf ◽  
B. Armbruster
Keyword(s):  
Power Spectrum ◽  
Autocorrelation Function ◽  
Power Spectra ◽  
Scanning Force Microscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Scanning Force ◽  
Lateral Structure ◽  
Scale Roughness

Optical interferometry, confocal light microscopy, stereopair scanning electron microscopy, scanning tunneling microscopy, and scanning force microscopy, can produce topographic images of surfaces on size scales reaching from centimeters to Angstroms. Second moment (height variance) statistics of surface topography can be very helpful in quantifying “visually suggested” differences from one surface to the next. The two most common methods for displaying this information are the Fourier power spectrum and its direct space transform, the autocorrelation function or interferogram. Unfortunately, for a surface exhibiting lateral structure over several orders of magnitude in size, both the power spectrum and the autocorrelation function will find most of the information they contain pressed into the plot’s origin. This suggests that we plot power in units of LOG(frequency)≡-LOG(period), but rather than add this logarithmic constraint as another element of abstraction to the analysis of power spectra, we further recommend a shift in paradigm.

Role of pinnae and head movements in localizing pure tones 1The authors would like to thank Mr. Remi Humbert for implementing the experiment in Turbo Pascal and for his further assistance.

1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet
Keyword(s):  
Sound Source ◽  
Head Movement ◽  
Movement Analysis ◽  
Head Movements ◽  
Sound Sources ◽  
Localization Accuracy ◽  
Sound Effects ◽  
Posterior Quadrant ◽  
Localization Performance ◽  
Pure Tones

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.

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