### Estimating iterations and match quality

Verfasst:

**19. Jul 2013 12:08**Hi,

I don't get how the number of iterations necessary for RANSAC is calculated. The formula from l10 slide 26 is pretty simple of course, but how do we get the probability of an inlier? Do we have to guess it completely random? Just to be sure: inliers in our case are point pairs that are matched correctly, i.e. both points in the pair represent the same point in world space?!

As I'm not able to get any decent homographies at all, could someone please have a look at my input and tell me, whether the matches I work with are accurate enough? I filtered out point pairs above a certain chi-squared threshold, but I'm not sure if this is sufficient, there are still a lot of nasty diagonals ...

Thanks a lot!

I don't get how the number of iterations necessary for RANSAC is calculated. The formula from l10 slide 26 is pretty simple of course, but how do we get the probability of an inlier? Do we have to guess it completely random? Just to be sure: inliers in our case are point pairs that are matched correctly, i.e. both points in the pair represent the same point in world space?!

As I'm not able to get any decent homographies at all, could someone please have a look at my input and tell me, whether the matches I work with are accurate enough? I filtered out point pairs above a certain chi-squared threshold, but I'm not sure if this is sufficient, there are still a lot of nasty diagonals ...

Thanks a lot!