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Here we will introduce some FAQs about Relative Illumination in 4 topcis:

* How is Relative Illumination calculated

* Considering Fresnel loss

* Situations that Relative Illumination cannot calculate

* Relative Illumination in systems with FOV > 90 degrees

* Cosine fourth Law

 

It's suggested to see also this forum post:

 


 

excellent post!!

That is great indeed!


It should be remembered that cos^4 is not a 'Law', it is simply the result you get with a simple system with no aberration. Distortion is the biggest (but not the only) effect is determining non-cos^4 behavior. If cos^4 was a Law, you woudn't need to compute it based on solid geometry!


There is an excellent paper about this from Ronian Sew on LinkedIn.



 

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