blog/2024/03/24/image-comparison/

[giscus[bot]]

blog/2024/03/24/image-comparison/

The personal blog of Josh Hendricks.

https://www.joshooaj.com/blog/2024/03/24/image-comparison/

[Uncle-Chicken]

HI!
I was looking for a way to nowadays check if somebody violated (my) copyright. I was thinking about uploading pictures to social media and before doing that i was looking for ways to protect them.
First i tried to manually add (a complex) non visible watermark which could only be seen when playing around with sharpness afterwards. Afterwards i applied one of those AI watermark removers and sadly it made that watermark non recoverable.
Afterwards i looked for other ways and ended up at your youtube video.

Would you say your tool / perceptual hashes are a way to proof it is my picture? (i just realized, it would only proof its "about" the same picture - not even mine) And how close does a hash even have to be to be able to say "this is the same (/this is mine)? Once the hash is different its not the same anymore and no proof?
Do you maybe know any way to nowadays protect own pictures?

Thank you and greetings :)

[joshooaj]

Because of how lossy the hash is, you definitely can't use it as proof that two images are the same. At best, you could use this method to filter for similar images that you would then check by other means. Maybe you pre-process images to find potential violations that you then verify by eye. Since this process only looks at brightness gradient patterns and not colors or lines/edges, you might find images with a similar hash that are very different but have similar composition.

I truly don't know what the best strategy would be to monitor for image/art copyright violations. My guess is it would probably be a multilayered approach where you look for obvious exact matches using a file hash using a SHA algorithm, then look for similarity maybe using something like this algorithm or maybe there's something you can use from the ImageMagick utility?