Is there any way to compute translation vector in a known unit like 'mm' or 'cm' between two planar objects using corresponding feature points. If yes, please let me know how can I do that.
So far I've tried with Essential Matrix computation (for non planer objects) and didn't get them in a known unit.
Thanking You in advance!
Only if you know the physical distance between some of those points (at least two) on the plane, so to fix the scale. Otherwise you are out of luck.
Without a reference distance, there is no way to tell whether you are looking at two buildings hundred of yards away, or two matchboxes nearby: this is how miniature visual effects in movies are done.