Top all-time · #4975
Vladimir Yuzhikov
Personal blog · yuzhikov.com/articles · on HN as YUVladimirprogrammingscience
Vladimir Yuzhikov's personal blog at yuzhikov.com covers programming and science. Since 2012, 15 different Hacker News readers have linked it 18 times, most often “Restoration of defocused and blurred images”. No feed was found, so read it on the site itself.
Restoration of distorted images is one of the most interesting and important problems of image processing - from the theoretical, as well as from the practical point of view. There are especial cases: blurring due to incorrect focus and blurring due to movement - and these very defects, which each o
Most-linked posts?
- Restoration of defocused and blurred images9 people · 9 mentions · first linked 2012-10-21
- Restoration of defocused and blurred images, Part 2 – Practice (2012)3 people · 4 mentions · first linked 2012-11-25
- /articles/BlurredImagesRestoration1.htm3 people · 3 mentions · first linked 2020-05-31
What Hacker News says?
Yes, that's it, thank you! And here's the English version of the article I linked above: https://yuzhikov.com/articles/BlurredImagesRestoration1.htm
Comment linking /articles/BlurredImagesRestoration1.htm
on “Image Scrubber: tool for anonymizing photographs taken at protests”Submitted Restoration of defocused and blurred images as a story · 354 points
HN discussionHere's a good read on undoing blurs: https://yuzhikov.com/articles/BlurredImagesRestoration1.htm The short explanation is blurs are kernels that spread a pixel's value across other pixels, so knowing this, you can treat blurred pixel values as a system of equations to solve.
Comment linking /articles/BlurredImagesRestoration1.htm
on “Image Scrubber: tool for anonymizing photographs taken at protests”Submitted Restoration of defocused and blurred images (2012) as a story · 215 points
HN discussionAs a toy example if you have pixels a,b,c and you blur to (a+b)/2,(b+c)/2, you can recover back c - a. You might be able to have a good estimate of the boundary condition ("a"), e.g. you can just use (a+b)/2 as an approximation for "a", so the recovered result might look fairly close. You'll basically want to look up the area of deconvolution. You can interpret it in linear algebra terms as trying to invert an ill-c…
Comment linking /articles/BlurredImagesRestoration1.htm
on “It's easier than ever to de-censor videos”Submitted Restoration of defocused and blurred images, Part 2 – Practice (2012) as a story · 37 points
HN discussionCheck out Deconvolution[1]) The technique has been done before and the text string of the private key would probably be the easiest point of attack. WHY BLURRING SENSITIVE INFORMATION IS A BAD IDEA[2] RESTORATION OF DEFOCUSED AND BLURRED IMAGES[3] Take away: black out any and all sensitive information. Blurring just marginally reduces the independence of the bits presented in blurred output. To have privacy, all dep…
Comment linking /articles/BlurredImagesRestoration1.htm
on “How we found rogerkver’s obfuscated wallet private key”Submitted Part 2. Restoration of defocused and blurred images as a story · 1 points
HN discussionhttp://yuzhikov.com/articles/BlurredImagesRestoration1.htm
Comment linking /articles/BlurredImagesRestoration1.htm
on “Host your own contacts and calendars and share them across devices”Submitted Restoring defocused and blurred images (part 2) - practical issues and solutions as a story · 1 points
HN discussionI'm author of this article (and SmartDeblur http://smartdeblur.net/ ), thank you for posting! Also, you can look at the second part that describes practical issues and their solutions: http://yuzhikov.com/articles/BlurredImagesRestoration2.htm And if you have any qustions, feel free to ask me.
Comment linking /articles/BlurredImagesRestoration2.htm
on “Restoration of defocused and blurred images (2012)”Funny how you present your view as fact and then complain about having to put up with myths... http://yuzhikov.com/articles/BlurredImagesRestoration2.htm
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on “Girl unaware all her pictures are sent to journalist”Paying for Blurity? Meh. There are free AND open source implementations out there, including SmartDeblur ( http://yuzhikov.com/projects.html ) that has been recently publicized all over the net. Here's a detailed article for those who are interested in image deconvolution: http://habrahabr.ru/post/147828/
Comment linking /projects.html
on “How we got a Y Combinator interview but blew it”As soon as I saw that edited photo with a blurred out face of the crack cocaine user, I was reminded of http://yuzhikov.com/articles/BlurredImagesRestoration1.htm
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on “The San Francisco Drug Economy”Blur can be reverted with deep neural networks. You should not rely on it for hiding sensitive info. http://yuzhikov.com/articles/BlurredImagesRestoration1.htm
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on “Show HN: Secure sensitive info while recording videos live or screen sharing”That's an example of bruteforce, but the blur itself can actually be reversed sometimes: http://yuzhikov.com/articles/BlurredImagesRestoration1.htm
Comment linking /articles/BlurredImagesRestoration1.htm
on “Show HN: Chrome extension to blur personal data before screen capture”They're simply averaged out after a number of trials. You're trying to scramble information that needs to be removed. It's like how a blurred image can be brought back into focus, but a removed one cannot, e.g. -- http://yuzhikov.com/articles/BlurredImagesRestoration1.htm
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on “Robust and Efficient Elimination of Cache and Timing Side Channels”It's the next part of previous article: http://yuzhikov.com/articles/BlurredImagesRestoration1.htm
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on “Restoring defocused and blurred images (part 2) - practical issues and solutions”
