Hello Jamie,
Short answer: you can't measure luminance with any software program. You need a light meter to do that.
Longer answer: You can calibrate your camera system with a light meter. But it is not easy. To do it accurately, you need to go through a detailed procedure. The camera may or may not save images in a linear intensity format, so you must determine the shape of any intensity nonlinearities of your camera.
Also, the sensitivity of your system varies with many factors. Each pixel in your camera is different.
Some references I found:
http://www.mpi-inf.mpg.de/resources/hdr/calibration/index.htmlhttp://www.astrophoto.net/calibration.htm
--
Harry Parker
Senior Systems Engineer
Digital Imaging Systems, Inc.
----- Original Message ----
From: "Feusner, Jamie" <
[hidden email]>
To:
[hidden email]
Sent: Saturday, August 18, 2007 3:04:07 PM
Subject: calculate luminance
Hello,
How do I calculate the luminance of an image in cd/m2, either in imagej, Scion Image, Photoshop, or some other program?
Thanks,
Jamie Feusner
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