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Deep image prior 'learns' on just one image

dmitryulyanov.github.io

21–30 of 235 posts

Re: Deep image prior 'learns' on just one image

#21
Wow:

"In this work, we show that, contrary to expectations, a great deal of image statistics are captured by the structure of a convolutional image generator rather than by any learned capability. This is particularly true for the statistics required to solve various image restoration problems, where the image prior is required to integrate information lost in the degradation processes.

To show this, we apply untrained ConvNets to the solution of several such problems. Instead of following the common paradigm of training a ConvNet on a large dataset of example images, we fit a generator network to a single degraded image. In this scheme, the network weights serve as a parametrization of the restored image. The weights are randomly initialized and fitted to maximize their likelihood given a specific degraded image and a task-dependent observation model.

We show that this very simple formulation is very competitive for standard image processing problems such as denoising, inpainting and super-resolution. This is particularly remarkable because no aspect of the network is learned from data; instead, the weights of the network are always randomly initialized, so that the only prior information is in the structure of the network itself. To the best of our knowledge, this is the first study that directly investigates the prior captured by deep convolutional generative networks independently of learning the network parameters from images."

PS. This makes me wonder whether and to what degree the structure of the brain's connectome might be a necessary prior for AGI.

Re: Deep image prior 'learns' on just one image

#23
post #4

Wow, so just the weight sharing architecture does so much already? I am wondering if the same could be done with LSTMs on sequences or CNNs on voice...

I'm wondering the same thing too.

Note also that this finding strongly suggests that neural net architecture actually is quite important, possibly even more important than having more data -- which contradicts the conventional wisdom!

Re: Deep image prior 'learns' on just one image

#27
post #3

i find it impressive how it placed a lamp over the library window. After that i was expecting a vase with flowers to be placed on the table in the next, palace shot :)

could you highlight which part this is ?. I think it can only fill in patterns that already exist in the image. I see a big artifact over the window but no lamp.

well, probably it is that deep (i hope) neural network inside my skull that interpreted the artifact as the lamp.

Re: Deep image prior 'learns' on just one image

#28
post #20
post #12

Earlier quoted context omitted.

It doesn't guess "correctly" at all. Zoom in on the image, and focus on the filled-in areas, they look really blurry. It just doesn't look very bad from a birds-eye view.

Somewhat similar to content aware fill in Photoshop [0]. The untrained network can latch onto frequent patterns and match them to holes in the data. Why doesn’t it paint everything white? Are these actually transparent images or are they somehow tagged? [0] https://helpx.adobe.com/photoshop/using/content-aware-patch-...

Yes, for the inpainting, the parts to be painted (big white deleted areas) are supplied as masks, so it doesn't try to match them.

Re: Deep image prior 'learns' on just one image

#29
post #15
post #5

Red Dwarf - "Uncrop" - http://www.dailymotion.com/video/x2qlmuy

Actually... How cool would it be to have an NN that could extend an image's background with plausible scenery? Not just photoshop 'smart' fill, but for example if it detected a building on the right side of an image, it could draw the rest of it? :)

[deleted]

Re: Deep image prior 'learns' on just one image

#30
post #21

Wow: "In this work, we show that, contrary to expectations, a great deal of image statistics are captured by the structure of a convolutional image generator rather than by any learned capability. This is particularly true for the statistics required to solve various image restoration problems, where the image prior is required to integrate information lost in the degradation processes. To show this, we apply untrain…

> PS. This makes me wonder whether and to what degree the structure of the brain's connectome is a necessary prior for AGI.

Well, I wouldn't mix up AGI and AGI by deep learning, and more important I would emphasise that this is a good prior for images. The fundamental insight in CNNs and eventually in this work is that there is a correlation between pairs of nearby pixels. We have something similar for video and audio processing, but nothing remotely similar for other more abstract intelligence tasks.

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