Slashdot Mirror
Colorizing Images and Video by Scribbling
Guspaz writes "Up until now, colorizing a video or image has been a painstaking and mostly manual task. However, researchers in Israel have come up with a new way of colorizing images just by making a few scribbles. The technique works on the premise that 'neighboring pixels in space-time that have similar intensities should have similar colors,' and also allows colorization of videos by 'marking' about one in ten frames."
I'm colorblind! That whole site is very confusing! :P
Back when voyager(s) were flying by planets I recall reading how the cameras worked. From what I remember, the cameras actually capture images in black and white. The cameras can detect much more "color" depth than color cameras could (or can?). The scientist would process the pictures to colorize them, you identify one area of color you know and the algorithm would process the rest of the 1 billion shades of gray into a color mapping for people to view. Now why cant identify this gray shade as the color red; anytime you see it then that is red. Go on for each color spectrum or have the algorithm adjust what a little red hue is for a given little hue of gray. It appears that is what the scribbles are doing which is quite clever and the algorithm doesn't have to work (guess) so much.
from looking at the before and after images, this technique looks pretty cool and will probably have applications for recoloring an image that is already color. For instance, the image where he recolors the fabric on the chair.
Video Compression !
Only save the intensity channel and a few bits of markup and you compress the stream quite a bit.
The bikini - security through obscurity since 1943
...and raise enought money to rebuild the smoking ruins of their server room.
I'm not wrong. You haven't thought about it hard enough.
Isn't that just a fill tool? Paint does that.
No. Fill just goes until it meets a boundary. This colorization is a lot smarter than that. It appears to notice the boundarys by the sudden changes of the temperature in the color of pixels. That way it can then make an educated guess on how much to color and when to stop. You can then optimize this by putting in more than one input of the colors you want to change. This effect is really quite amazing. Scroll down and look at the gif video of the birthday party. JUST AMAZING.
I'm a virgo and on Slashdot. Coincidence? Yes.
> Personally I can't wait until there is a Photoshop filter for this. :D
You have misspelled Gimp..
This work is very similar to some work that was presented at last years siggraph using graph cut optimization titled Interactive Digital Photomontage by some researchers at the University of Washington. This stuff is really cool and has applications outside of just re-coloring black and white. For example, compositors in the film industry adjust the color composition of scenes that were filmed during the day to look like they were filmed at night. Sometimes they just need to tweak the color because the art director isnt happy with it. Other times it's because they introduced CG elements into live action scenes and they dont quite match. If they can tweak those colors interactively, without authoring masks, it is faster than re-rendering the scene and that saves money.
Very cool stuff.
Pete
What's a sig? Pete Brubaker
Are you listening, Mr. Lucas?
In Soviet Rush, today's Tom Sawyer gets high on you.
No kidding. Even if you are not doing colorization, the boundry detection algorithm he is using kicks ass over the "magic wand" tools in both photoshop and gimp. Perhaps it is the fact that it is doing several "magic wands" at once and boundries are determined by what matches the best, rather than just "does this match good enough".
The site is slashdotted so I cannot read it, but i wonder if something akin to this could be used for compressing motion video. For example the intensity is encoded with currrent techniques, but instead of the color being encoded at a lower resolution, instead only a very small amount of colored points are encoded. Then during the decoding, the decoder uses an error function, intensity, and the time domain of previous and future frames to 'fill' the colors out.
-Don
Take a look and feel free: http://www.PieMenu.com
That feels better now.
Take a look and feel free: http://www.PieMenu.com
I tried out their matlab code and put a few example colourings on my web page, for the interested:
http://www.inference.phy.cam.ac.uk/cjb/
Hey, that is actually true!
What's this? a slashdotter who knows what he's talking about?
He's a witch!
It's easier to fight for one's principles than to live up to them.
" The technique works on the premise that 'neighboring pixels in space-time that have similar intensities should have similar colors"
Interestingly, the retina exploits that same property of natural scenes to compress images. This correlation between luminance and color is an opportunity to throw out redundant information. The eye multiplexes color and luminance information over a single channel, transmitting luminance while discarding color at high spatial frequencies and transmitting color while discarding luminance at low spacial frequencies. First reported by C.R. Ingling, color/luminance multiplexing is an inherent property of the linear color-opponent center-surround receptive field. For a good explication of the subject, see:
Vision Res. 1985;25(1):33-8."The spatiotemporal properties of the r-g X-cell channel."
Ingling CR Jr, Martinez-Uriegas E.
Abstract: Analysis of the simple-opponent r-g receptive field of the X-channel shows that it is tuned to both high and low temporal frequencies, high and low spatial frequencies, and that its spectral sensitivity is both chromatic and achromatic.
Ceci n'est pas une signature.
Take a few deep breaths, you'll get over it. In the meantime, I can spread some disinformation if you want. Hmmm...
The MPEG standard, knowing that porn tends to drive the industry, actually contains several optimizations for drawing things such as skin tones and nipples. Really.
Make me a friend and I'll mod you up
24 bits per pixel X 4 pixels = 72 bits
In other news, mathematicians still agree that 24 times 4 is 96.
YUV 4:2:0 saves 50% bits over YUV 4:4:4, more info on wikipedia (per usual) http://en.wikipedia.org/wiki/Chroma_subsampling