DocumentCode :
3091268
Title :
The use of instantaneous phase for improving sparse arrays images
Author :
Prado, Vander ; Higuti, Ricardo T. ; Kitano, Claudio ; Martinez-Graullera, Oscar
Author_Institution :
Fac. de Eng. de Ilha Solteira, Univ. Estadual Paulista, Ilha Solteira, Brazil
fYear :
2013
fDate :
21-25 July 2013
Firstpage :
974
Lastpage :
977
Abstract :
Sparse arrays have pitch larger than halfwavelength (λ/2) and there is a reduced number of elements in comparison with a full-populated array. Consequently, there is a reduction in cost, data acquisition and processing. However, conventional beamforming techniques result in large side and grating lobes, and consequently in image artifacts. In this work the instantaneous phase of the signals is used in a beamforming technique instead of the instantaneous amplitudes to improve images obtained from sparse arrays configurations. A threshold based on a statistical analysis and the number of signals used for imaging is applied to each pixel, in order to determine if that pixel is related to a defect or not. Three sets of data are used to evaluate the technique, considering medical and non-destructive testing: a simulated point spread function, a medical phantom and an aluminum plate with 2λ-, 7λ- and λ-pitch, respectively. The conventional amplitude image is superposed by the image improved by the instantaneous phase, increasing the reflectors detectability and reducing artifacts for all cases, as well as dead zone for the tested plate.
Keywords :
acoustic signal processing; aluminium; array signal processing; optical transfer function; phantoms; plates (structures); statistical analysis; structural acoustics; ultrasonic imaging; Al; aluminum plate; beamforming; data acquisition; data processing; grating lobes; image artifacts; medical phantom; medical testing; nondestructive testing; reflectors; signals; simulated point spread function; sparse arrays; statistical analysis; ultrasonic imaging; Acoustics; Antenna radiation patterns; Array signal processing; Arrays; Gratings; IP networks; Imaging;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Ultrasonics Symposium (IUS), 2013 IEEE International
Conference_Location :
Prague
ISSN :
1948-5719
Print_ISBN :
978-1-4673-5684-8
Type :
conf
DOI :
10.1109/ULTSYM.2013.0250
Filename :
6724800
Link To Document :
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