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Recovering Blurred Text Using Photoshop and JavaScript 157

Posted by timothy
from the careful-how-you-hide-stuff dept.
An anonymous reader writes "There's been a lot of talk about recovering blurred or pixelated text, but here's an actual implementation using nothing but Photoshop and a little JavaScript. Includes a Hollywood-esque video showing the uncovered letters slowly appearing."
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Recovering Blurred Text Using Photoshop and JavaScript

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  • Just ovveride? (Score:5, Insightful)

    by Dreen (1349993) <dreen1@@@gmail...com> on Wednesday October 08, 2008 @06:43PM (#25306737)
    I never understood why people use pixel mis-mashing when they want to obfuscate something in an image.

    drawing a big black rectangle is 10x faster and there is no way you can de-obfuscate that
  • by Empiric (675968) on Wednesday October 08, 2008 @06:50PM (#25306827) Homepage

    Is it not the case that the reason this works is because you're running the -same blur algorithm- with the -same input- (the unblurred letters/pixels) and simply iterating through the letters and looking for equivalent output?

    Presumably, the blur algorithm output could resolve such that multiple unblurred letters resolve to the same blurred pixels, but even if it is not this trivial to map the input state to output state, it still wouldn't seem to me to approach solving the general case of letters "blurred" by any arbitrary means, which is the real-world capability implied by the article.

    What am I missing here?

  • Re:Just ovveride? (Score:5, Insightful)

    by Jabbrwokk (1015725) <grant.j.warkenti ... om minus painter> on Wednesday October 08, 2008 @07:04PM (#25306961) Homepage Journal

    Absolutely agree.

    Plus TFA says the original image was blurred using the Photoshop "mosaic" filter. So this approach, while interesting for text blurred using that exact filter, is probably useless in most real-world approaches, such as trying to recover text obliterated with the rubber-stamp tool, or like you suggest, a black box.

  • by X0563511 (793323) on Wednesday October 08, 2008 @07:05PM (#25306973) Homepage Journal

    I imagine the "cheating" aspect of using a PSD file is that you are working with a lossless image. There's no JPEG/MPEG compression going on etc. Working with another lossless format like BMP, or PNG, would probably work just as well.

  • Re:Just ovveride? (Score:1, Insightful)

    by Anonymous Coward on Wednesday October 08, 2008 @07:12PM (#25307033)

    Better is to blur something completely different from the original. Then if someone decodes it all they will get is a funny message about them wasting their time (or maybe a big "fuck you" or something).

  • Failure (Score:5, Insightful)

    by sexconker (1179573) on Wednesday October 08, 2008 @07:13PM (#25307051)

    "While my original goal of recovering the censored text on my friendâ(TM)s page was never achieved, the project was a success."

    I wouldn't call that a success...

    Good execution of a basic concept, but the fact remains that this shit is infeasible in practice. You have all the font issues (the typeface, the spacing, the color, the size, etc.), and you've got all the source issues - Are you sure that's text? Is it English? Was it obfuscated in other ways? Has the image been altered after the text was rendered? How has compression affected it?

    The biggest fucking issue, of course, is that you're assuming the text was obfuscated using photoshop, or at least very similar blurring/pixelating algorithms.

    It's a great project in terms of using javascript and photoshop to do something neat but basic in concept (essentially brute forcing, as the author says).

    But unless you have inside info about how the text was rendered and obfuscated, you're better off taking a step back and squinting.

    I think I see a duck.

  • Re:Just ovveride? (Score:5, Insightful)

    by More_Cowbell (957742) * on Wednesday October 08, 2008 @08:19PM (#25307573) Journal
    Not quite sure if that is funny or disturbing... :)
  • by vodevil (856500) on Wednesday October 08, 2008 @08:36PM (#25307725)
    I think people would be more interested if this removed the blur from nipples.
  • Re:Just ovveride? (Score:1, Insightful)

    by Anonymous Coward on Wednesday October 08, 2008 @08:50PM (#25307839)

    disturbunny is disturbed.

  • by Anonymous Coward on Wednesday October 08, 2008 @09:30PM (#25308171)

    Remove the text you want hidden and replace it with some lipsum of believable length and general consistency. Apply standard mosaic filter. Simple, relatively quick, no special software needed.

  • randomize after (Score:3, Insightful)

    by pikine (771084) on Wednesday October 08, 2008 @10:55PM (#25308749) Journal
    If you randomize pixel in any way before applying mosaic, adding noise or just randomly permute the pixels around, then what you get in the mosaic is going to be the same colored blocks that look like a solid colored strip. That's because mosaic computes the average of the pixel values that fall under the block, which would be the same for all blocks if randomness is evenly distributed. However, if you apply mosaic first and then randomize the blocks after, then the result looks much more like mosaic and yet is irreversible.

FORTRAN is a good example of a language which is easier to parse using ad hoc techniques. -- D. Gries [What's good about it? Ed.]

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