Start Field II by writing Field_II_GUI at the Matlab prompt and
define a rectangular array transducer with one active element with a size
of 2 x 5 mm. Note that all units in the Field II program are SI units.
Generate an image of a point on the axis, but 10mm in front of the focus.
Explain qualitatively the appearance of the response. Repeat the calculation
for other off-axis positions of the point and explain the change in the
image.
Find the point spread function of the TX pressure field for the aperture
for a focal distance of 10, 40, and 80 mm from the transducer surface.
Explain the difference between the responses.
Repeat the same calculation for the pulse-echo response and explain the
difference.
You can experiment with other apertures and find the response from them
(use e.g. a concave focused aperture, a piston transducer, or some
multi-element types).
