Timelapse Color Issues

Well, I have been handed a handful of time lapse shots of factory assembly robots. These were shot with a digital SLR.

Problem is there are slight shifts in the brightness. Sometimes frame to frame and sometimes there will be several consistent frames and then it shifts again.

This of course causes flickering in the image.

I have tried adjusting frame by frame but there is just to much material for that.

Is there a way to automate say matching the darkest area, the lightest and then the gamma over a string of frames instead of one at a time.

Thanks for any info!

The flickering is probably due to using a lens without a physical iris ring, or to setting the exposure in the camera, rather than by manually setting the iris. (there's play in there...) There's been some discussion on this. Try a search in the archives for "exposure variations" or "flicker"

Color Stabilizer, in the Pro version of AE, will help with this. It's designed to keep specified areas in each frame consistent from frame to frame. Results can be pretty good. I think Twixtor also makes a dedicated plug in.

good luck
randy

Randy,

Thanks for that input. It's all running though AE first anyhow to resize/reframe/zoom the images and produce a quicktime to go to FCP. I gave Color Stabilizer a quick shot and I think it will do the trick. Not perfect but I didn't play with the settings much. The results were better than my hand tweaking on just the first attempt. I'll take a look at the Twixtor plug as well.

Thanks again

The flickering could be caused by the DSLR being set to Auto White Balance rather than the white balance being set manually. Even a slight change in color balance could cause flickering if this is the case. You could try setting up a batch process in photoshop to match the pallete of each individual frame to a "master frame". Tried this method a few times and it has often been a quick and sometimes not too nasty way of minimizing flicker.

If you get the chance try this method before you use Color Stabilizer and good luck.

Randy,
Tried Color Stabilizer and it worked pretty well. Added Wide Time and set it for 2 frames forward and 2 frames back. That cleaned up what flicker was left and it's completely clean now. Thanks.

Graeme,
I figured there must be some way to batch this in Photoshop but didn't know how to do it. Any pointers? Otherwise I will try to feel my way through that process as it might be a more direct solution to the root of the problem. Thanks.

Don"t have access to any version of PS at the mo so this is from memory, you might have to fill in the gaps. Take a frame from the sequence you are working with and add adjustment layers to taste... this is now your master frame. Merge layers and leave the file as an open document within PS. Open the first frame of your sequence. Make sure that the Show Actions window is open and click on New Action or New Set then New Action, name the new set/action and the record light in the action window should light up. Click on Match Palette in (I think) the Image Adjust drop down menu, you should then be given a selection of all open documents. Choose the document that you have just corrected and this will match palette to your master frame. Now save the image to your desktop and the hit the stop button on the Action Menu. Go to the Automate Batch option in the file menu, target the folder that contains the images you want to process in Source and choose the Destination folder that you want to save the processed images into, hit OK and the batch process should start.

Sorry for the convoluted explanation. It is a bit of a hit and miss affair I have to admit but I hope the suggestion helps.

Let me know how you get on.

I'll give it a try tomorrow. Thanks for the help!

Ah?good tips, both. I hadn?t tried WideTime for cleanup, but will.

Graeme, how?s processing time in PS? I?ve got a bunch of perspective corrections to do, and am more familiar with PS than AE, but I?ve shied away from it, thinking it would take forever?

randy

rrotheisler Wrote:
-------------------------------------------------------
>
> Graeme, how?s processing time in PS? I?ve got a
> bunch of perspective corrections to do, and am
> more familiar with PS than AE, but I?ve shied away
> from it, thinking it would take forever?
>
> randy

Hi Randy

Reasonably quick on a quad core Mac Pro depending on how involved the processing is. I use PS for processing lots of time lapse footage shot on DSLRs and also for "abstract" effects in animation pieces. I find that I can do things in PS that I can"t do in either AE or Shake... but I think that has more to do with the fact that know PS much more than I know either Shake or AE.