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View Full Version : converting grayscale (black&white) video to rgb (color) video


RiOt
19th July 2003, 21:30
I originally started this thread, July 15th, 2003 (Doom9's Forum > Announcements and Chat > General Discussion > Greyscale to RGB conversion) My objective (goal) is also stated within those threads. To sum, I want to covert old grayscale home videos to good quality. I want the quality to be very good, photo realistic or near photo realistic quality. (very much like monochrome photo images are converted to color) I wanted to know if software like Avisynth or Virtualdub was capable of this task. If this wasn’t possible I wanted to know if there was software within the $500.00 price range that was capable. Despite asking this question and waiting for answers I came up with some interesting information. http://www.neuraltek.com/ (Neuraltek) makes such software. They even colorize grayscale video. The proprietary software they use is called TimeBrush. They can excellently colorize 30 minutes of monochromatic video for $25,000. Well, I have about 1 hours worth of home videos that I want properly colorized. I Can’t do $50,000. This lead me further into this matter. Perhaps the method used by TimeBrush is akin to one of the following and if it isn't perhaps one of the following links can be inciteful (a stepping stone):

1) http://www.cs.sunysb.edu/~tfwelsh/colorize/index.html and http://mrl.nyu.edu/projects/image-a...s/colorize.html
2) http://www.cad.zju.edu.cn/home/dzh/...eo%20Colorizing
3) http://www.icip03.upv.es/technical_program.htm search for subject(title) "Colorization Algorithm for Grayscale Image by Propagating Seed Pixels"
4) http://www.icme2003.com/Papers/Publ...?Sessionid=1027
(There are also very helpful links and *.pdf’s from the sites listed)

After seeing some of the program algorithms used I don’t believe this is way over my head anymore. I’m a mediocre C++ programmer and don’t know anything technical perse about video but I’m willing to learn. I believe it’s a matter of having the right tools and knowing how to use them. I’m hoping that this is were Virtualdub and or avisynth come into the picture. Can someone help me or point me in the right direction? I have to thank the moderator Wilbert for the helpful information he gave me and for pointing me in this direction. Perhaps the results can be useful to anyone interested and won’t cost $25,000 - $50,000.

Malcolm
21st July 2003, 12:46
Very interesting!

But some of your links don't work. Probably a copy&paste error!

Malcolm

Mug Funky
29th July 2003, 09:47
hmm. i couldn't find anything on the timebrush site but meaningless marketing patter.

the word "neural net" doesn't solve all the problems black and white film presents us with. sounds a bit rich to me.

but from what i can intuit about the problem of colourising black and white, a graphical user interface is essential or you'd go insane, even on a system well in advance of what's available today.

so that pretty much rules out avisynth. it'd be awesome to see it happen, but i didn't find "timebrush" convincing at all... no samples i could find, comparisons, or any attempt at an explanation less mystical than saying AI does it all...

i'll check out the other links. good thread! i'm really interested in this problem now... (anyone see the "heart shaped box" video? hand coloured black and white. that's why it looks so spooky.)


[edit]

wow, those research links were pretty useful...

i think using the swatch matching technique thing, maybe some Xvid code could be modified to do this... after all, MPEG compression usually consists of a motion search for the luma (greyscale) part only, and the chroma is assumed to follow logically. if motion searches were combined nicely with this still image colour transfer, then there could be some nice things happening.

i don't think avisynth could do this alone... but it could plug into premiere or after effects which has the existing interface stuff...

definitely a good post. too bad a good solution doesn't exist for you in this case, but if demand for this sort of thing is high enough, i would expect there could be a practical solution in a couple of years.

morsa
8th August 2003, 09:57
I've got good result with learning filter colorizing some smal videos.It is terribly slow and I'm not using Avisynth.I guess developing a kind of filter that interpolates missing frames would be more usefull for this task than this filter.I mean you could use the chroma from the interpolated frames to paste it on the original ones giving them color.Also remember that the colorized sequence should begin with a colorized first frame and posibly some kind of color key frames.