Stolen images ..... How to check

swag72

swag72

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Sara
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I am trying to ascertain whether someone has used images that aren't theirs in making their image. I'm searching online with regards to finding an invisible watermark within an image - yet all I can find is how to create one. Can anyone give me some tips as to how I can best check a persons image?
 
I have yes - The image is an astronomy image, so as I'm sure you can appreciate one galaxy image taken by Mrs X looks very similar to the same galaxy image taken by Mrs Y. This is why I was wondering about an embedded / hidden signature and how you can find one in an image.
 
There are loads of invisible watermarking tools out there... just google it. Digimarc is probably the best known. It can still be read after manipulation, and unless severe.. cropping.
 
I was googling specifically how to read them and find them and came up with Digimarc as you mention and a whole host of information about how to make them. Is there any other way to read them except Digimarc? I don't want to create an invisible watermark - I just want to check an image to see if it has one.
 
swag72 said:
I was googling specifically how to read them and find them and came up with Digimarc as you mention and a whole host of information about how to make them. Is there any other way to read them except Digimarc? I don't want to create an invisible watermark - I just want to check an image to see if it has one.
Click to expand...

The whole point of Digimarc is that it can ONLY be read by digimarc... it's truly invisible, as it is not embedded as visible information, and unless you have Digimarc, you'll never know.
 
Ok thanks for that. If an embedded watermark has been added by another piece of software then that can't be read by Digimarc then ............... Looks like this scamp will get away with it.... :(
 
No... digimarc will only read a watermark put there by itself. Has he stripped all metatdata from the image?
 
Maybe invest in Digimarc then for future use. Or find a way to hide it with reduced visibility layers that can be brought back in post.
 
You can use other tools - if Mrs X has taken a photo of a galaxy and Mrs Y has taken a photo - they <will> be different, what you need is something that will compare it byte for byte. The only issue will be making Mrs X copy of the image is resized and JPG quality exactly the same.

What about the camera serial number being stored in the EXIF? Is that available? (I assume thats what David is hinting at?)
 
Hope you get it sorted.
 
I know.... but looking forward... finding a way to encode your own will prevent this in future... that's what I was thinking.
 
swag72 said:
I have yes - The image is an astronomy image, so as I'm sure you can appreciate one galaxy image taken by Mrs X looks very similar to the same galaxy image taken by Mrs Y. This is why I was wondering about an embedded / hidden signature and how you can find one in an image.
Click to expand...

I thought there were discrepancy checking methods with astro images with the potential to show copies or not? I think I recall in the days before digital it was called "blink viewing" or analysis. Put simply as I understood it when the two images are overlaid unless taken (in the case of distant objects) at the same time of the year and broadly from the same hemisphere there should be differences detectable in star positions or other transient objects crossing the field of view. Though if the image(s) show a very distant object in isolation then that I suppose will not 'work'?
 
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