06:47 am, 5 Sep 06
coded exposure photography
Coded Exposure Photography:
In a conventional single-exposure photograph, moving objects or moving cameras cause motion blur. The exposure time defines a temporal box[via Behdad]
filter that smears the moving object across the image by convolution. This box filter destroys important high-frequency spatial details
so that deblurring via deconvolution becomes an ill-posed problem.
Rather than leaving the shutter open for the entire exposure duration, we ``flutter'' the camera's shutter open and closed during the
chosen exposure time with a binary pseudo-random sequence. The flutter changes the box filter to a broad-band filter that preserves
high-frequency spatial details in the blurred image and the corresponding deconvolution becomes a well-posed problem. We demonstrate that
manually-specified point spread functions are sufficient for several challenging cases of motion-blur removal including extremely large
motions, textured backgrounds and partial occluders.
Except these guys forgot to mention that, uh, terrorists often drive fast and elude capture because of motion blur.
I'm wondering whether a shutter like this could be implemented via a standard SLR lens attachment, or whether it requires a new camera. (They used a standard camera, but they might have had to hax0r it by gluing the internal shutter open and/or groping the camera's electronics.)
At the other end of the scale, I bet this could be used to make cheapo cameras, like those on cellphones, work a lot better by letting them use longer exposures.
Awesome
Looks like the current version only solves linear blur. All motion seems linear for a small time window, though. Not hard to imagine a future version detecting each independent region of motion, running the algorithm on a locally-rectified region, and stitching it back together.Too bad they didn't do it via firmware hacking instead of building their own Frankenstein camera, then others could play. :-)
Re: Awesome
You can't flutter a physical shutter fast enough. They made it out of a funky material that turns clear when you send a current through it.Re: Awesome
Whoa. Yeah, I guess I didn't really do the math on the shutter speeds.Re: Awesome
Reminds me of the original Rapatronic cameras.