The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we derive and analyze causal equations describing propagation of attenuated pressure waves. We also review standard models, like frequency power laws, and the thermo-viscous equation and show that they lack causality in the ...

in this paper, some meteorological data, such as temperature, pressure and dew point temperature are used for extracting the atmospheric refractivity in different locations of iran. these data have been measured at different heights in twelve radiosonde sites of country by using meteorological balloons. the set of refractivity points obtained from data of each site are plotted as a function of ...

Attenuation measurements can be derived from the decay of backscattered signal with depth in an inhomogeneous material. In cases such as liver tissue, where many small inhomogeneities are likely to be included in sample volumes defined by pulse and beam widths, Rayleigh statistics describe the random nature of the magnitude of backscattered pressure. The statistics of speckle underlie the uncer...

Attenuation estimation and imaging in the cervix has been utilized to evaluate the onset of cervical ripening during pregnancy. This feature has also been utilized for the acoustic characterization of leiomyomas and myometrial tissue. In this paper, we present direct narrowband substitution measurement values of the variation in the ultrasonic attenuation coefficient in ex vivo human uterine an...

Digital filtering is one of the main fundamental aspect of Digital signal processing, So Digital filters are widely used in many digital signal processing applications. In this paper low-pass FIR filter is implemented using an efficient adjustable window function based on Blackman window function. In this adjustable window function for a fixed length the bandwidth of main lobe and side lobe amp...