The influences of ambiguity phase aberration profiles on focusing quality in the very near field-part II: dynamic range focusing on reception

For pt. I see ibid., vol. 49, no. 1, p. 57-71 (2002). The influences of ambiguity phase aberration profiles, including constant, tilted, and quadratic profiles, on focusing quality have been quantitatively analyzed with the very near field approximation for single range focusing on transmission. In this paper, their influences are analyzed in a very different situation: dynamic range focusing on reception, which is commonly used in medical ultrasound imaging for beam formation on reception. It is shown that the results for dynamic range focusing on reception are dramatically different from those for single range focusing on transmission. For example, constant phase aberration profiles are harmless to focusing quality for single range focusing on transmission but become harmful for dynamic range focusing on reception. The analysis also shows that, compared with single range focusing on transmission, dynamic range focusing on reception is much more sensitive to ambiguity phase aberration profiles, which have adverse effects on focusing quality even in the near field and far field. These significant differences are caused by the fundamental differences between single range focusing and dynamic range focusing as well as between transmission and reception. Numerical and simulation results are also derived to test the correctness and accuracy of the theoretical results.