five-point algorithm produces several solutions. How to check the real one?

Question

I use five-point algorithm to calculate essential matrix referring to http://users.cecs.anu.edu.au/~hongdong/new5pt_cameraREady_ver_1.pdf . Finally, I got 4 solutions after eliminating the roots of which imaginary part are non-zero of equation C(z) = 0. Is there any technique to determine the true estimate?

Answer 1

suppose you have got the four candidate solution. as we have known, the five point we use to determine the essential matrix are all in front of both two camera.

therefore, them you can triangulate just one of the five point using the four candidate solution, them there are only one candidate suffice that the point stay in front of both of the camera.

that candidate is the "true estimate".

for a more detail explaination and visualizaiton, you can refer to the book "Multiple view geometry in computer vision",second version page 259 9.6.3 https://www.amazon.com/Multiple-View-Geometry-Computer-Vision/dp/0521540518/ref=sr_1_1?s=books&ie=UTF8&qid=1487321676&sr=1-1&keywords=multiple+view+geometry+in+computer+vision

i hope this answer can help you.