what does key_frame mean?

[xjock]

image_dir, key_frame, output_dir

[cbuntain]

It should refer to the key image you want to be the center and origin against which other images you provide are matched.

[nowsyn]

I just want to know, if the given src image has no keypoints then how to do?
because i want to stitch some images which contains images without keypoints. That is, i can't get keypoints after using sift. I have been troubled for several days. If there is a solution, i would be appreciate it.