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Pencigraphy: Image Composites from Video
jafuser writes: "Prof. Steve Mann (of cyborg fame) has a detailed technical description on his site that demonstrates a method of transforming video into a high resolution composite image. Pictures are seamlessly mosaiced together to form one larger picture of the scene. Portions of the video that were "zoomed in" will result in a much clearer region in the final picture. I wonder if this could be used in a linear sequence to 'restore' old video to higher resolutions? It's on sourceforge; download and play!" Mann has been experimenting with such composites using personal video cameras for years.
Juding from the description found in that article, I believe that it is possible to enhance old video to higher qualities. However, the quality of color sometimes cannot be enhanced no matter what. Unless one has access to the original film reel, it is unlikely that any sort of improvements could be made; video copies are utterly useless in this manner. Anything from before 1990 in VHS is much worse quality, case in point being the John Woo film A Better Tomorrow. The problem with these videos is that not only is the quality blurry, but the color blending is off and sometimes exceeds the lines it should, creating distorted images. I've seen this in a lot of older movies... I wonder if there's a way to correct this. :)
At any rate this looks very promising indeed... it'd be cool to see some of the old classics in better quality.
The new method, which allows an image to be created by ``painting with video'' is used in conjunction with a wearable wireless webcam, so that image mosaics can be generated simply by looking around, in a sense, ``painting with looks''.
Just in case anyone was wondering - this wasn't being done in anything close to real-time the last time I checked. There's a cluster in Prof. Mann's lab which is dedicated to compositing these images (my cube is in the next room).
Still an interesting project. The affine transformation approach has been well-understood for some time (you do a brute force and ignorance test of promising-looking affine transformations [rotations and scalings] to find one that matches the new image to the old). As far as I can tell, he's doing the same thing with a different coordinate system that has a bit less distortion.
My undergraduate design project was with Steve Mann on this technology (objective was the "parallelization" of the software on a Beowulf cluster - shout out to Mike and Anna :) ).
:)
The main use of this system so far has been to stitch multiple images into one panoramic shot. Like any auto-stitching program, this requires a certain amount of overlap between frames - the more overlap, the better the stitching. The code works remarkably well, automatically rotating, zooming, skewing and otherwise transforming the images to fit together and then mapping them into a "flat" image as opposed to a parallelogram-shaped one.
Yes, the higher resolution from multiple shots of the same scene works, and is a very cool effect of the system. Of course, this requires a more or less static scene.
Finally, it's not necessarily "video" that it uses, although pulling individual frames from a video would work. It's based of the head-mounted cameras of the wearcam systems, which essentially use a stripped-down webcam for image-gathering, so you already know the fps and resolution limitations involved with those.
Of course, in the 2 years since I've been there, the technology has probably improved, although I doubt the webpage has.
Mann has a bunch of cool projects involved with the wearcam/wearcomps. This is a great one, another is the Photoquantigraphic Lightspace Rendering (painting with light), which can also be found on the wearcam site.
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This is a gateway to pingpong-ball-less motion capture. In future with sufficient processing power and algorithyms, it ought to be possible to combine two lenses spaced apart for stereo, combined with x,y,and z axis positioning sensors. Such a device could record stereo data, combined positional data and the understanding that objects "grow" as the come closer", to make 3D models of anything it sees. The more time it can watch an object and rotate/zoom around it, the more detailed the model can be. It doesn't even have to make the model in realtime, just record as much data as it can then upload it to more powerful computers later. When does Minority Report take place? 2050 or so? Well by then I fully expect that instead of the flat holograms Tom Cruise watched we'll have full 3D.
You know how televisions shows will pixelate the face of someone that doesn't want to be show on television? Sometimes it is just a passerby on MTV's Realworld who won't sign a release, but sometimes its somebody a little more important like a corporate or federal whistle-blower.
I've long thought that pixelization wasn't a very good way to protect the identities of these people because when they are on video, they move around and the camera sometimes moves around, but often the pixelization is applied in post-production so it stays in a relatively constant location rather than tracking the features on the person's face. Anyone sufficiently motivated and sufficiently equipped with the right tools ought to be able to reconstruct a much higher resolution, non-pixelated image of the secret person's face by extracting all of the useful information from each frame and then corollating it all together with the general movements of the person in the frame.
It sounds to me like pencigraphy is exactly the kind of science required to do something like that. So now the question is, who do we want to unmask? Too bad Deep Throat never made an on camera appearance.
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