Fig. 4.

Skull-induced aberration compensation of PA signals produced from a 0.1 mm absorbing sphere passing through a skull tissue. (a) Skull thickness is 2 mm and the target is located at 5 mm depth (PA signal is contaminated with 10% background noise), (b) skull thickness is 2 mm and the target is located at 5 mm depth (PA signal is contaminated with 20% background noise), (c) skull thickness is 1 mm and the target is located at 20 mm depth (PA signal is contaminated with 10% background noise), and (d) skull thickness is 1 mm and the target is located at 20 mm depth (PA signal is contaminated with 20% background noise). (i) Signal amplitudes and (ii) signal gradients. In this simulation, there is a 5 mm layer of ultrasound gel between the ultrasound transducer and the skull.