Program sfiwipert | Image-domain waveform tomography (image perturbation). 
[SYNOPSIS]
sfiwipert < in.rsf > out.rsf pz=pz.rsf ph=ph.rsf thres=0.01
[PARAMETERS]
string  | ph | = |   | 	auxiliary input file name
string  | pz | = |   | 	auxiliary input file name
float   | thres | =0.01 |   | 	slope thresholding 
[DIRECTORY]
user/llisiw
