Fast Style Transfer takes a very long time to train a style model (and the output models can be somewhat large; the pre-trained models in the Dropbox are 20MB), but the styles can be applied quickly. Fast Style Transfer is the technique that is used by Prisma/Facebook. This repo is the first I've seen that uses TensorFlow instead of lua/Torch dependency shenanigans, and as a result should be much easier to set up. (this code release also beats Google's TF code release for their implementation: https://research.googleblog.com/2016/10/supercharging-style-... )
EDIT: Playing around with this repository, I can stylize a 1200x1200px image on a dual-core CPU on a 2013 rMBP in about 30 seconds.
Normal Style Transfer is ad-hoc between the style image and the initial image; it can only be used for one image at a time, but overall it is faster than training a model for Fast Style Transfer (however, this is infeasible for mobile devices).
EDIT: There's a catch. The checkpointed models are calibrated for smaller images, so you'll get better styles with smaller images. Larger images tend to just have images repeated: https://twitter.com/minimaxir/status/793161755992002560
The jumping fox video does looks a bit 'off' though, I think because the animation is kept the same and so it ends up looking too realistic for that style. Still this is early days!
https://github.com/lengstrom/fast-style-transfer/blob/master...
(Original photo: https://github.com/lengstrom/fast-style-transfer/blob/master... )
With the "Great Wave" painting as the network's style input, the limitations of the technique become more apparent. It's clear that a human painter would never render the Chicago skyline in this way: there are incongruent little waves on buildings' edges and all over the sky.
The antennas on top of the tallest tower are particularly revealing. The neural network just sees an area of higher local contrast, and has continued the same pattern that was applied in the sky at the top-right of the antennas but with more contrast applied. This doesn't make any sense for what's supposed to be a painting.
There's no intelligence here, "just" pattern matching that can do a brilliant illusion of creative variance on the right kind of content. ("Just" in quotes because it's still a great achievement.)
Merely because sometimes it gets things wrong, and I think a normal human could correct things if they had more control over the process.
Don't know if there's an analog way for fast style transfer.
