using imshow inverts the y value
help text in figure
multiprocess raw processing
explicit tmp format
Revert "explicit tmp format"

This reverts commit e1ee92cfe0d8af3f3cc3821c23c7dbb7675dbe2a.
barrel correct using StringIO

https://gist.github.com/dgouldin/1411980#file-gistfile1-py
http://stackoverflow.com/questions/12694230/python-pil-reading-png-from-stdin
return images as generator
Stitch over known overlap
switch to allow explicit load image to memory

this is needed because for runs with lots of files we get
an error when trying to process because the number of open files exceeds
the limit set by the OS (see `ulimit -n`).

We can get around this by explicitly loading the images to memory and
then discarding the file object that they came from.

https://mail.python.org/pipermail/image-sig/2010-May/006299.html

This is sub optimal as it takes up lots of memory. It is only a problem
when using parallel_process - if this could accept a generator as input
then there would be no issue as we are using generators throughout here.
synchronisation script

used to extract frames from all of the videos.

this used the whistle transient as the method of synchronisation.

i think there is still potential in using the light switch transient.

it should also be possible just to convolve the audio streams, but i
haven't made this work yet. In principle you just have to take the cross
correlation of the two signals, or the convolution with one of them
reversed (use scipy.signal.fftconvolve), whilst zero padding the signals
so that you don't cycle round.

http://dsp.stackexchange.com/questions/736/how-do-i-implement-cross-correlation-to-prove-two-audio-files-are-similar
https://gist.github.com/endolith/376572
http://stackoverflow.com/questions/7697169/padding-arrays-using-numpy