Color / brightness / contrast consistency in time lapse photography
 

Hi - I have been dabbling with time lapse video in Vegas Pro 8 lately. Here is my very first attempt:

YouTube - Clouds Time Lapse, Take 1

Overall, I think it came out ok, but after I started putting it together, I realized I had set my camera's metering to spot, so some portions - especially with clouds in the center of the frame - tend to have a darker sky, and it shows in the video.

So, is there an easy way to correct this? I could not come up with anything obvious in Vegas. I also tried a second video (not online) with fixed exposure, and found that some frames still turned out differently enough to cause a flickering effect.

One thing I have been considering is Image Magick. This is a command line utility to manipulate photos, and it can measure certain things like min and max values for each color channel. Could I take a single frame, and set the levels for all other frames to match, or is that naive thinking?