That code is non-functional and only meant as an example to start your
printf("\nSigh: This program is not complete/will be replaced. \n"
"So: Use this just to see hints of how to use things like
" conversions, finding the fundamental matrix, using
" finding and matching in features2d and using camera
"Usage: build3dmodel -i <intrinsics_filename>\n"
"\t[-d <detector>] [-de <descriptor_extractor>] -m