Frequency domain compensation for inhomogeneous layers in ultrasound holography.
A frequency-domain compensation method is presented that is based on the ultrasound holography B-scan (UHB) imaging principle. In an acoustic imaging system, the wavefront-angle-dependent distortions caused by any kind of known inhomogeneous reason can be compensated by this method. It is applied here in the frequency domain using the so-called rear-ranging operation for the longitudinal distortion and the multiplication of phase factors for the lateral distortion. The method is especially suitable for compensating different velocity layers in acoustic imaging systems. The results of both computer simulations and water-tank experiments are promising.
Qin
Z D
ZD
Dept. of Electr. Eng., Oulu Univ.
Tauriainen
A
A
Ylitalo
J
J
Alasaarela
E
E
Lu
W
W