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Deep image prior 'learns' on just one image

dmitryulyanov.github.io

91–100 of 235 posts

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

#91
Maybe it's the presentation of the restoration process, but I'm particularly impressed with the inpainting sample.

The idea of not running the simulation `past` the realistic interpretation and using that result makes sense but the results are way beyond what I would have expected!

Great work on the write up.

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

#93
post #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!

It's not about neural network architecture. CNNs are taught by presenting them overlapping pieces of image. To speed things up and keep things orgsnized this is not done sequentially but in parralel making multiple neurons share weights but this is just a trick.

So what makes this result possible is not the architecture of NN in CNN but rather architecture of C. That allows us to get multiple samples from single image. The rest is just that actual content of the image is easier to learn then the noise.

Brain is almost nothing like CNN.

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

#94
post #80

Earlier quoted context omitted.

The “task dependent observation model” also comes out of thin air, or is it trained with lots of data?

Observation model is trivial and data-free. For example, just mean squared error for denoising, mean squared error of downscaled image for super-resolution, etc.

I'm fairly certain that's not? Where in the paper does it talk about this other network, generally called the discriminator?

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

#95
post #90
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…

I don't understand their editorializing > contrary to expectations, ingore the weasel words > a great deal of image statistics are captured by the structure of a convolutional image generator rather than by any learned capability. > 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…

The point is that a fully connected network would not get you the same results. I.e. the convolutional structure allows it to learn interesting things from a single example because by choosing a convolutional architecture, you are implicitly imposing a prior.

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

#96
post #80

Earlier quoted context omitted.

Observation model is trivial and data-free. For example, just mean squared error for denoising, mean squared error of downscaled image for super-resolution, etc.

I'm fairly certain that's not? Where in the paper does it talk about this other network, generally called the discriminator?

There is no discriminator in this work. Read the paper.

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

#98
post #23

Earlier quoted context omitted.

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!

There is some pretty strong evidence for this: all the toddlers in the world. You only need to show them something once and they'll immediately be able to recognize more examples of the same thing from different angles and even when it is partially hidden. All they have to guide them is the structure of their brains, not the quantity of data they have been exposed.

Seems like this view gets told every once in a while by someone who clearly hasn't been around any 0-2 year olds.

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

#99

Earlier quoted context omitted.

There is some pretty strong evidence for this: all the toddlers in the world. You only need to show them something once and they'll immediately be able to recognize more examples of the same thing from different angles and even when it is partially hidden. All they have to guide them is the structure of their brains, not the quantity of data they have been exposed.

"All they have to guide them is the structure of their brains, not the quantity of data they have been exposed." A typical toddler (say 12 months' old) has spent 4000-5000 hours with open eyes. Even if you assume a low frame rate (10fps), resolution (1080p), and a 1000:1 compression ratio, that's still 1TB of training data.

Also, find me a 12 month old that can recognize an object after seeing it once.

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

#100
post #85

I don't see how any choice of a function g(theta) could have the property they desire, ie could eliminate R(g(theta)). Can anyone explain?

It's expressed somewhat awkwardly, but what's going on is that R(x) is zero if x is in range of g, and infinite otherwise. Choice of g is such that natural images are in range of g, and non-natural images aren't.
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