Thank you for posting your question to Science Buddies. After doing some research concerning your topic, I think I've come up with something you may like to try. I haven't attempted it myself (my digital camera is not up for the task), but theoretically it should work. First though, unfortunately I don't see that there is any single software (at least in the range of free to cheep) that will stitch and perform individual pixel analysis and color code them based on intensity.
That being said, a good (free) image stitch program is called Hugin. A link to it's operation and the software can be found here: http://lifehacker.com/378490/stitch-pho ... e-software
I suggest taking your images encompassing the entire horizon and working your way up to Zenith with a nominal 20% - 30% image overlap, as suggested in the link. Using Hugin, stitch them together into a single image 0 to 360 degrees azimuth by 0 to 90 degrees elevation. Be sure to document very well which image corresponds to which look angle. Then using ImageJ, as suggested in the SB project procedures, analyze consecutive areas of the images using procedures from Step 7 thereby obtaining average pixel intensity for that area (vs intensity for every single pixel in each image). If you can, I would try to select sections of the images at some small increment like 1 or 0.5 degrees. Repeat this process until you've analyzed the entire panorama image you've created. Assign colors to intensity ranges (i.e. 0 < 100 = white; 101 < 200 = green; etc…) and plot them on a polar plot. You can do this in excel with some effort, but I’d look for a program, like matlab that can handle such operations much better. This will entail a lot of manual processing, but I think in this case “brute force” method is going to be your best bet.
Please post back with any other questions.
All that said, I’m not a computer programmer by trade, so if a programming expert has some other advice, feel free to correct or amend my advice.
I hope this helps.
"As the circle of light increases, so does the circumference of darkness around it."
~ Albert Einstein