Derivation of formula (2), inverse homography

[zikuicai]

Can anyone help explain the derivation of formula (2) in the paper?

I understand the equation (13.2) from [Hartley and Zisserman 2003]:

However, I still find it hard to understand what's in the parentheses of formula (2), especially the denominator.
Can anyone help? Many thanks in advance.

[iszihan]

I have the same confusion, did you find an answer to this?

[zikuicai]

Yes. You can use Sherman-Morrison formula to find the inverse homography.

[Jaswers]

Sherman-Morrison formula