How is relative illumination measured?

MichaelM

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Hello,

I would like to understand how the relative illumination charts are created.

Example:
http://www.edmundoptics.de/images/articles/fig-1-rs.gif

I suppose that it is done, by rotating a lens with respect to a constant light source. However, in articles realted to relative illumination I often find references to the cos4 law, which, if I get it right, refers to looking at a "wall" with labertian radiance beahviour. I also read, that the cos4 law does actually not reffer to the object side of the lens, but the image side.

As you can see, I am quite confused. So, please help me understand.
 
oh man,
this is going to be one of those geek threads i don't understand isn't it.
 
Well that depends. Check out a couple of these and get back with us with a written an oral report on what you leaned.:biggrin-93:

https://smartech.gatech.edu/bitstream/handle/1853/3656/92-01.pdf
http://360vr.com/fisheye41/coastal-fisheyep.pdf
https://optics.synopsys.com/lighttools/pdfs/illuminationfund.pdf
http://www.cs.utah.edu/~shirley/papers/gi90.pdf
Illumination
http://white.stanford.edu/~brian/papers/ise/Maeda-Optics-SPIE-EI-5678-5.pdf

Remember
10% of your grade will come from the pop quizzes.
10% of your grade will come from your weekly Homework assignments.
20% of your grade will come from your oral report.
20% of your grade will com from your written report.
50% will come from the mid-term and final.

We hope you enjoy the semester.:bouncingsmileys:
 
Well that depends. Check out a couple of these and get back with us with a written an oral report on what you leaned.:biggrin-93:

https://smartech.gatech.edu/bitstream/handle/1853/3656/92-01.pdf
http://360vr.com/fisheye41/coastal-fisheyep.pdf
https://optics.synopsys.com/lighttools/pdfs/illuminationfund.pdf
http://www.cs.utah.edu/~shirley/papers/gi90.pdf
Illumination
http://white.stanford.edu/~brian/papers/ise/Maeda-Optics-SPIE-EI-5678-5.pdf

Remember
10% of your grade will come from the pop quizzes.
10% of your grade will come from your weekly Homework assignments.
20% of your grade will come from your oral report.
20% of your grade will com from your written report.
50% will come from the mid-term and final.

We hope you enjoy the semester.:bouncingsmileys:

I see it isn't a math class. ;)
 
Well that depends. Check out a couple of these and get back with us with a written an oral report on what you leaned.:biggrin-93:

https://smartech.gatech.edu/bitstream/handle/1853/3656/92-01.pdf
http://360vr.com/fisheye41/coastal-fisheyep.pdf
https://optics.synopsys.com/lighttools/pdfs/illuminationfund.pdf
http://www.cs.utah.edu/~shirley/papers/gi90.pdf
Illumination
http://white.stanford.edu/~brian/papers/ise/Maeda-Optics-SPIE-EI-5678-5.pdf

Remember
10% of your grade will come from the pop quizzes.
10% of your grade will come from your weekly Homework assignments.
20% of your grade will come from your oral report.
20% of your grade will com from your written report.
50% will come from the mid-term and final.

We hope you enjoy the semester.:bouncingsmileys:

I see it isn't a math class. ;)
VERY GOOD! I was wondering how long it would take someone to catch the 110% grade total. For that you don't have to do the oral report. You get an A for that 20% of your grade. :biglaugh:
 
Oh, and thanks for posting the link to that book - very informative. All this time I thought relative illumination was just a fancy term for the "glow" my niece had when she was pregnant.
 
would have helped if you had posted the page from which that image was taken. I'd never heard of a relative illumination chart and had to do some digging to figure out what was meant by it. Anyway, if you read through that page, and then read the linked page within the article:

The Relative Illumination curve is used to quantify changes in the illumination level across the sensor. Changes in illumination can have undesired effects on the final image when it comes to analysis. Details on what causes RI changes can be found in Sensor Relative Illumination, Roll Off and Vignetting. The curve in Figure 3a shows a typical relative illumination curve, with the relative brightness (relative to the brightest point in the image) vs. field height.

...


The x-axis represents the distance from the center of the sensor to the corner of the sensor. The y-axis indicates how much illumination exists at any position in the field relative to the point of highest illumination, typically the center of the field, set equal to 100%.

I imagine they measure this using an integrating sphere - no need to rotate the lens right? Just take an image and analyze the luminance information across it.
 

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