Right now, people around the world are marching and protesting against racism and police brutality, outraged by the most recent police murders of George Floyd and Breonna Taylor. At Signal, we support the people who have gone into the streets to make their voices heard. We believe that something ...

Blur tools for Signal: if you take or edit photos of crowds or strangers with Signal, you can use our face blur tool to quickly hide people’s biometric face data.

You can then export the photo from Signal if you want to post it publicly.

  • Szymon@lemmy.caEnglish
    241·
    1 year ago

    I recall a story of a pedophile being caught because they posted pictures using a radial warp on the face. It wasn’t too hard for enforcement to code a filter that undoes the radial warp, and instantly saw the original photo to identify and lock away the creep.

    • m-p{3}@lemmy.ca
      45·
      1 year ago

      A warp doesn’t technically lose the information, it merely displaces it. A good blur algorithm on the other hand will lead to loss of information.

      • AeroLemming@lemm.eeEnglish
        17·
        1 year ago

        To my knowledge, it’s kind of hard to quantify exactly how much information is lost with a normal blurring algorithm (gaussian, box, etc), but it’s usually less than you think. There are certain edge cases where no information is lost at all and the original image can be perfectly reconstructed if it’s simple enough. Even if it’s a normal photo of something complex, a deconvolution algorithm can work seemingly impossible magic on a blurry image without the need for an AI that will hallucinate details.

        On the other hand, pixelating part of an image provably removes a large amount of information from that section of the image and no algorithm will be able to de-pixelate something without hallucinating details. Using a big box is the absolute best because it just deletes all information from that part of the image.

        ETA: the problem is a lot worse in videos because you can use multiple frames with different offsets to reconstruct a higher quality image even if it’s pixelated.