Normalized Cross-corelation in terms of sums

[Henry1]

As per attached image , Normalized cross corelation can be expressed in terms of sums.But step by step explanation of the formula is not given.
Can anyone expand the formula step by step.

 

[Deleted member 4993]

As per attached image , View attachment 14894Normalized cross corelation can be expressed in terms of sums.But step by step explanation of the formula is not given.
Can anyone expand the formula step by step.

Did you do a Google search on "normalized cross-correlation"?

Read some of those referenced papers - and tell us if you did not understand and exactly where did you get lost.

 

[Henry1]

I know how the first equation in the image attached is derived but I am not able to derive the second equation from the first equation as written in the image that " replacing I bar with .... and multiplying the numerator & denominator by N yeilds "