Is the measured signal similar to the expected value of the detector? The formula looks very similar to the expected value for a continuous distribution we saw earlier in the semester.
it might also be similar to convolution
There isn't really an expected value here since we don't have any randomness, but if we introduced some randomness into the system (like only sending one wavelength at a time with pdf given by the s function) then it could be similar!
We can kind of think of this as an expected value, if we think of the detector sensitivity r(λ)r(\lambda)r(λ) as the "probability" that the detector detects light with wavelength λ\lambdaλ.