Determination of luminance value/brightness

Hello, 

for an eyetracking experiment, I would like to determine the luminance value/brightness of different digital pictures and equalize these values. Does this function exist in Photoshop Elements and if yes, how does it work? Is it also possible to determine the luminance value/brightness of a video?

Thank you very much in advance,

Katharina

By @KTBN22

I don't think this Elements forum is the good one to start with.

For discussion about scientific aspects of light and color, I would recommend asking in the 'Color management' forum where you'll find the best experts.

https://community.adobe.com/t5/color-management/ct-p/ct-Color-Management?page=1&sort=latest_replies&filter=all&tabid=all

If you get good advice and solutions of your issue with the full Photoshop, then you might get help to see if those solutions are applicable in some way in Elements.