The software looks good although some basic sketches of the geometries, transducer positioning, materials, axes, naming conventions, etc. should be included in the instructions in order to understand basic examples and develop more advanced ones.
Function "expsweep" works fine, it does what it is intended to do.
On the other hand function "sweepIR" does give an error in line 36: rec=rec(t:end,:); I changed it by rec = rec(1:length(t), :); but I cannot get it to work.
Another thing, use of word "offset" is a reserved word for MATLAB so I had to change it by something else.
Finally, variable Nimp is not documented as to what it is!
Please provide a corrected version of the function and it should work fine.