How to use a polynomial fit equation for offset update in microbolometer thermal

I have a microbolometer thermal sensor(tec-less, without shutter), I want to develop an easy shutter-less algorithm to recompense the temperature drift. For that, in the literature, a third order polynomials can be used to have a offset correction.
However, I did not understand how to proceed. I have a thermal images bank captured for an ambient temperature between 20 and 35 C. I have for each pixel a curve of its values vs temperature (20 to 35 C). With the help of matlab, I can have the coefficients of the 3rd degree polynomial(f(t) = ax3+bx2+cx+d). But after, I do not know how to use it to have an new offset value that changes automatically when the temperature change.

did you have an idea plz?