| Vibro-acoustography (VA) displays the vibroacoustic response of the object (tissue) induced by two intersecting ultrasound beams of different frequencies. VA image of a given object may vary depending on boundary conditions. Such variations are attributed to the reverberation of the sound emanating from the object in the acoustic environment of the experiment. This effect can be explained in terms of acoustic propagation through multiple paths before reaching the receiving hydrophone. The goal of this study is to reduce VA image variations caused by the acoustic multipath. Two methods based on channel estimation are developed to evaluate the effect of multipath and correct the received acoustic data from the object. The first method uses two ultrasound excitation pulses having different length for every image location. Another method uses tissue responses of different excitation amplitudes to remove reverberation and measure tissue nonlinearity. |