inlier matches more than putative matches

[shiu...@gmail.com]

Hi,

From my understanding the inlier matches were verified from putative matches and it should less than putative matches. However i found that the inlier matches were more than putative matches in the same image pair when I enabled SiftExtraction.estimate_affine_shape=true and SiftExtraction.domain_size_pooling=true. 

Is this normal and may I know why?

Thank you.

[Johannes Schönberger]

Did you enable guided matching? In this case, the inlier matches can be more.

On Mon, Apr 13, 2020, at 11:46 AM, shiu...@gmail.com wrote:
> Hi,
>
> From my understanding the inlier matches were verified from putative
> matches and it should less than putative matches. However i found that
> the inlier matches were more than putative matches in the same image
> pair when I enabled SiftExtraction.estimate_affine_shape=true and
> SiftExtraction.domain_size_pooling=true.
>

> inlier.png

>
> putative.png
>
> Is this normal and may I know why?
>
> Thank you.
>

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> Attachments:
> * inlier.png
> * putative.png

[shiu...@gmail.com]

Hi Johannes,

Thank you for your reply. 

Kind regards,

On Monday, 13 April 2020 19:25:20 UTC+8, Johannes Schönberger wrote:

Did you enable guided matching? In this case, the inlier matches can be more.

On Mon, Apr 13, 2020, at 11:46 AM, shiu...@gmail.com wrote:
> Hi,
>
> From my understanding the inlier matches were verified from putative
> matches and it should less than putative matches. However i found that
> the inlier matches were more than putative matches in the same image
> pair when I enabled SiftExtraction.estimate_affine_shape=true and
> SiftExtraction.domain_size_pooling=true.
>
> inlier.png
>
> putative.png
>
> Is this normal and may I know why?
>
> Thank you.
>
>  --
>  You received this message because you are subscribed to the Google
> Groups "COLMAP" group.
>  To unsubscribe from this group and stop receiving emails from it, send

> an email to col...@googlegroups.com.

[Ash Doshi]

Hi Johannes,

This is a followed up question regarding inlier matches being more than putative matches.

I looked at the code for TwoViewGeometry and specifically where it estimates the homography and fundamental matrices. Based on the best ratio obtained from one of them, it runs the ExtractInlierMatches function. This basically extracts the inlier matches from the putative matches, i.e. inlier is a subset of putative. With the guided matching flag ON, how does this give more inliers compared to putative?

Kind regards,

Ash.