Good day, I am having difficulty understanding the derivation below.
This is adopted from Simon Prince's computer vision book, pg 543 for the derivation, pg 626 for the inversion relation.
I can not understand how can we get from the red arrowed line to green arrowed line. My attempted derivation for that specific part (the only part that changes) ended up with equation in the skin colour box. Please help out, thanks in advance.
