Tools for automated notation: webcam movie to PGN Sometimes during blitz games over the board, or when in zeitnot, it gets very difficult to annotate them.

I've seen several software / hardware to help in writing the notation, even one that's FIDE approved; these require that you repeat the moves on the device. Hardly faster than pen and paper, just as prone to errors, plus you risk typing the wrong move and wasting even more time.  

DGT makes a board that will do this automatically, but it will only work with its pieces, and starts at 400€, double that for tournament boards.  Some independent projects are available such as usb chessboard 101, or voice controlled chess robots, Chess board step sequencer.  Additionally some open projects are available that even move pieces (or gigantic pieces).

I have a playoff tonight, and the tournament rules dictate shorter and shorter games until there is a winner.  Hence I thought about shooting a movie of the board should we lose track.  But then my programming background kicked in and I thought "there must be some software that can process a movie and write the PGN". 

I searched everywhere, and found nothing. 


Does any such thing exist (webcam/video to pgn converter)? A prototype maybe? 
Has anyone attempted such a feat and shared their research?
Are there obvious limitations that make this project unlikely to succeed?
Would you buy it if it existed?
It's 2019-12 now and 5 years after the original question.


Does any such thing exist (webcam/video to pgn converter)? A
prototype maybe?

see 


https://github.com/WolfgangFahl/play-chess-with-a-webcam/issues/19
https://github.com/WolfgangFahl/play-chess-with-a-webcam/issues/22
which are both closed by now. See http://lichess.bitplan.com for a game successfully recorded. Join https://gitter.im/play-chess-with-a-webcam/community to discuss

Has anyone attempted such a feat and shared their research?

Yes - so far I found some 35 research papers and some 10 open source solutions and one commercial offering

2.1  http://wiki.bitplan.com/index.php/PlayChessWithAWebCam/Papers 

2.2. http://wiki.bitplan.com/index.php/PlayChessWithAWebCam#Open_Source_Projects

2.3. http://wiki.bitplan.com/index.php/PlayChessWithAWebCam#Commercial

http://wiki.bitplan.com/index.php/PlayChessWithAWebCam is another project
aiming at the goals stated by you. The project was started 2019-10-15 and in a few hours I already found a lot of resources e.g. this Question
Some two months later I have updated my answer (see links above)
Are there obvious limitations that make this project unlikely to succeed?
I can only answer from my own experience with a similar project I did 31 years ago see http://wiki.bitplan.com/index.php/MagneticSensorChessBoard1987.
At that time i tried to create a chess board that would detect moves. I used magnets
in the wooden pieces and reed contacts. The key to success was using a chess engine
that new "the rules" to be able to concentrate on movements alone and not having
to detect individual pieces. As outlined in an answer above promotions to non queen
pieces might be one of the edge usecases that are difficult. Detecting the motion of
pieces via picture differences is a well understood problem.

Chess engines and UCI compatible GUIs are also available these days. So the problem
is more an integration problem these days then solving the individual detail issues.

A major obstacle is the difference between a "prototype" and a product. See e.g. 
http://www.nandanbanerjee.com/files/ICCVR-08AUG12-011%20paper.pdf 

a paper that is even older than this question but far from a product that you can buy
at a reasonable price.
Would you buy it if it existed?

Yes. When I bought a new chess board a few days ago I was looking for one that
could record moves and it was still around 500 EUR. As it looks the hardware cost
will be well below 150 EUR these days including a decent chess board and pieces.

The software might well be opensource and free (as in free beer) soon. I'll update
this answer accordingly.