I'm putting the Optris calculations into a spreadsheet -- the following is documentation of the formulae used in readable form
From the Optris "IR Basics" documentation (Page 7)
From the actual object temperature (To) and ambient (Ta)
To Actual temperature e
emmisivity
Ta Actual ambient C a
constant in the calorimeter
Tp Temperature of pyrometer
n exponent -- depends on wavelenght
U = C *( e*To^n + (1- e)*Ta^n - Tp^n)
Measured temperature reported by the calorimeter
Tm Measured temperature
Note : the optris equation uses the same symbol
for Tm and To ---
so it seems to be self-referential
Tm = root(n,(U - C*Ta^n + C*e*Ta^n + C*Tp^n)/ C*e)
Note that a lot of the "e" cancel out, leaving
1/e terms
root(n,val) can be computed as power(val,1/n)
-- some languages have problems with this
Pm Total power calculated from Tm
Pm = a * e * ( Tm^4 - Ta^4)
I'll put these equations into the spreadsheet and see what happens for various
"n" (wavelength) and "e" emmisivity
