inverse polynomial

[bing ai]

Hi Group and Prof. Scaramuzza,

I have one question regarding the inverse polynomial of the Scaramuzza Omni model:

the inverse polynomial coefficients are composed in Line 17 in Davide Scaramuzza OCam Calibration Toolbox omni3d2pixel.m,. Would you mind helping me understand the math/physics behind it? Not sure why only (end-1) coefficient is changed and only changed by m(j).

Thanks,

Bing