Re: [CinePaint] Looking for a feature useful to smooth timelapse sequences - grading
Bob Friesenhahn <[email protected]>
| Newsgroups | gmane.comp.video.cinepaint.user |
|---|---|
| Message-ID | <[email protected]> |
On Wed, 22 Nov 2006, John Arrowwood wrote: > > Obviously, I know about ImageMagick. I was using it. Unfortunately, > using the histogram normalization doesn't quite work, because it does > some truncation. And because the histogram curve is not guaranteed to > be exactly where it needs to be from frame to frame. Mind you, it got > it closer. But it also had undesirable side-effects. Right. Histogram normalization is like pounding a tack with a large hammer. It maximally expands the contrast so that the images look sharper on a computer display. It is useless for inter-frame use and not usually what you want for film images. > As much trouble as I'm having just communicating what it is I'm trying > to do, can you see why I am having trouble searching for a tool that > does it? I don't know, maybe you would call it inter-frame exposure > or levels smoothing or something like that... It seems like what you need is a tool that analyzes the image minimum, maximum, and mean, for each image over a sequence of images. Then it would compute a correction value for each image. Maybe it would smooth the computed values using a filter function (across frames) in order to allow gradual changes over time. ImageMagick's -level option can then be used to adjust each image's parameters. The -level option works similar to Photoshop's "Adjust Levels" dialog. This sort of work is likely very time consuming and the results are dependent on the nature of the images and what is intended. Bob ====================================== Bob Friesenhahn [email protected], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV