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Recovering redacted information from pixelated videos

positive.security

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Re: Recovering redacted information from pixelated videos

#31

Post by MauranKilom »

slingnow wrote: post #20

Funny how the whole article talks about this approach, and then at the end shows the approach failing in the real world. I don't know about you, but I can't conclusively come up with a license plate in that final video.

Sure, but the technique used was also very trivial. Just aligning and averaging all the video frames basically leaves a mosaic-pixel-sized blur on everything (assuming the camera movement is uncorrelated with the mosaic grid).

You can get much further by applying deconvolutions and using more math. I've been meaning to put some time into this myself but never got it off the ground.

I wonder if the author would be open to making e.g. the car data available?

Re: Recovering redacted information from pixelated videos

#32

Post by [deleted] »

rndgermandude wrote: post #28
Pxtl wrote: post #27

Earlier quoted context omitted.

I assume I got down-voted by people cranky about AMP links.

I basically only saw "Barry O'Bama" at first, and thought "oh good, another rightwingey troll/rant". I managed to pick up on the PULSE GAN before my mouse made it over to the downvote button, tho, so it wasn't me. I think you'd be better off just adding half a sentence of tl;dr like "... Barry O'Bama, where PULSE GAN incorrectly reconstructed a pixelated image of Barack Obama, resulting in a white guy that didn't loo…

[deleted]

Re: Recovering redacted information from pixelated videos

#33

Post by [deleted] »

hwers wrote: post #24
GistNoesis wrote: post #8

Even the best can make obvious mistakes. "I hacked a hardware crypto wallet and recovered $2M [video]" https://news.ycombinator.com/item?id=30067340 Showing a blurry 16 out of 24 trezor wallet seed words https://youtu.be/dT9y-KQbqi4?t=1720

That probably isn't very useful since the video isn't moving.

[deleted]

Re: Recovering redacted information from pixelated videos

#34

Post by 0des »

rndgermandude wrote: post #28
Pxtl wrote: post #27

Earlier quoted context omitted.

I assume I got down-voted by people cranky about AMP links.

I basically only saw "Barry O'Bama" at first, and thought "oh good, another rightwingey troll/rant". I managed to pick up on the PULSE GAN before my mouse made it over to the downvote button, tho, so it wasn't me. I think you'd be better off just adding half a sentence of tl;dr like "... Barry O'Bama, where PULSE GAN incorrectly reconstructed a pixelated image of Barack Obama, resulting in a white guy that didn't loo…

How can we avoid comments like these in the future?

Re: Recovering redacted information from pixelated videos

#35

Post by fy20 »

archi42 wrote: post #26
sumtechguy wrote: post #10

Earlier quoted context omitted.

Is anyone using this sort of idea on upscaling videos?

AI upscaling? Yes. Seems like some fans used AI upscaling for the older Star Gate SG-1 seasons, since these were direct-to-VHS and hence shot on low quality media (by now there are official bluray releases which are also somehow upscaled, but I was told those would be of inferior quality compared to the fan effort). Not sure if those efforts worked on a frame-by-frame basis or used information across frames. [edit] h…

And to think we all laughed at CSI enhancing CCTV images...

Re: Recovering redacted information from pixelated videos

#36

Post by breakingsystems »

MauranKilom wrote: post #31
slingnow wrote: post #20

Funny how the whole article talks about this approach, and then at the end shows the approach failing in the real world. I don't know about you, but I can't conclusively come up with a license plate in that final video.

Sure, but the technique used was also very trivial. Just aligning and averaging all the video frames basically leaves a mosaic-pixel-sized blur on everything (assuming the camera movement is uncorrelated with the mosaic grid). You can get much further by applying deconvolutions and using more math. I've been meaning to put some time into this myself but never got it off the ground. I wonder if the author would be ope…

> I wonder if the author would be open to making e.g. the car data available?

Here you go:

- The stabilized frames out of blender (with 4 blurry frames in a separate folder): https://breaking.systems/plate_frames_sorted.zip

- The original video in case you'd like to improve the stabilization as well: https://breaking.systems/plate_vid_orig.mp4

Would love to hear back in case you'll tackle it!

Re: Recovering redacted information from pixelated videos

#37

Post by Grustaf »

MauranKilom wrote: post #31
slingnow wrote: post #20

Funny how the whole article talks about this approach, and then at the end shows the approach failing in the real world. I don't know about you, but I can't conclusively come up with a license plate in that final video.

Sure, but the technique used was also very trivial. Just aligning and averaging all the video frames basically leaves a mosaic-pixel-sized blur on everything (assuming the camera movement is uncorrelated with the mosaic grid). You can get much further by applying deconvolutions and using more math. I've been meaning to put some time into this myself but never got it off the ground. I wonder if the author would be ope…

Yes, I've also always felt there must be ways to extract more data from a moving clip, precisely because of the effect he explains, but then it seems that just superimposing the images doesn't actually extract that information, at least not all of it.

But I wonder how to actually do it, do you have concrete ideas for a simple algorithm?

Re: Recovering redacted information from pixelated videos

#38

Post by throwawayciv651 »

Syzygies wrote: post #11

As University libraries have moved online, one reads many poorly scanned journal articles. I often wonder about taking the time to clean them up. What replaces temporal information here is the same characters appearing over and over. So of course I read this article hoping to learn about an off-the-shelf tool that would do a great job of scanned text reconstruction. Alas, the best candidates were "no code available."

Not off the shelf but here are some tools. I have no experience with them.

Wolf binarization - I think it makes the text more clear before OCR.

https://github.com/chriswolfvision/local_adaptive_binarizati...

This thing OCRs the pdf using Tesseract OCR

https://github.com/ocrmypdf/OCRmyPDF/

Two other pdf tools

https://github.com/qpdf/qpdf

https://github.com/pikepdf/pikepdf

Re: Recovering redacted information from pixelated videos

#39

Post by josefx »

archi42 wrote: post #26
sumtechguy wrote: post #10

Earlier quoted context omitted.

Is anyone using this sort of idea on upscaling videos?

AI upscaling? Yes. Seems like some fans used AI upscaling for the older Star Gate SG-1 seasons, since these were direct-to-VHS and hence shot on low quality media (by now there are official bluray releases which are also somehow upscaled, but I was told those would be of inferior quality compared to the fan effort). Not sure if those efforts worked on a frame-by-frame basis or used information across frames. [edit] h…

The remastered edition of Command and Conquer also used AI up scaling for the cut scenes. They lost the original recordings and the videos from the PlayStation release were the best they could track down. The result is far from perfect but probably the best one could hope for https://www.youtube.com/watch?v=ikJLYYTrIxs&t=689s.

I previously replied to the wrong comment on accident.

Re: Recovering redacted information from pixelated videos

#40

Post by josefx »

fy20 wrote: post #35
archi42 wrote: post #26

Earlier quoted context omitted.

AI upscaling? Yes. Seems like some fans used AI upscaling for the older Star Gate SG-1 seasons, since these were direct-to-VHS and hence shot on low quality media (by now there are official bluray releases which are also somehow upscaled, but I was told those would be of inferior quality compared to the fan effort). Not sure if those efforts worked on a frame-by-frame basis or used information across frames. [edit] h…

And to think we all laughed at CSI enhancing CCTV images...

Luckily we can track the amount of lawsuits filled against Ryan Gosling to see if the police started to submit AI up scaled images as evidence. https://petapixel.com/2020/08/17/gigapixel-ai-accidentally-a...
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