[photogem]

Adam recently brought me to a Linux based program for forgery detection:
GitHub - andrewlevandoski/Image-Forgery-Detection

It worked only partly and then stopped.

So I asked a young and very talented person if he can help me with it.

He did and found a mistake with the source-code and rewrote the program:

Here it is and it works:


GitHub - MrcJkb/Image-Forgery-Detection

This was the test:

and the result was:

"Forgery" is the act of impersonating another in the production of a document, particularly by signing a name other than one's own. So I'm not sure exactly what this program is actually doing in this context.

[swanlefitte]

particularly by signing a name other than one's own.

This confused me. Did Samuel Clemens commit forgery by signing Mark Twain?

The program detects alterations. I think someone claiming to have a photo of a shark swimming in a pool when it was photoshopped in could be considered forgery couldn't it?

[jatrax]

"Forgery" is the act of impersonating another in the production of a document,

Not everyone on this forum has English as their first language. I suspect the use of 'forgery' was meant in a more generic sense. Alteration, fake, modified etc. The program is clearly looking at an image and trying to see if it has been digitally altered. "Photoshopped" as it is sometimes called.

[MossyRocks]

I'm kind of curious how this will work with some very processed images. Not necessarily ones that have been pushed hard in a raw developer but I'm curious what it will do with a heavily processed astro image.

[Michail_P]

Interesting.. but given the fact that it is a variance based software, I would really like to know how it can be practically useful.

[Parallax]

"Forgery" is the act of impersonating another in the production of a document, particularly by signing a name other than one's own................

Surely you're aware that legal definitions and common definitions can differ. Indeed that would be the definition in law of forgery as a verb, but Merriam-Webster defines forgery as a noun as "something forged". It defines something forged as:
2 :made falsely especially with intent to deceive
// forged signatures
//a forged document.
A photo that was photoshopped with intent to deceive would, by definition, be a forged document (or an electronic representation there of.)

Forgery | Definition of Forgery by Merriam-Webster
Forged | Definition of Forged by Merriam-Webster

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Last edited by Parallax; 05-18-2021 at 11:07 AM.

This confused me. Did Samuel Clemens commit forgery by signing Mark Twain?

No, because his pseudonym was his own name. If he'd published it under the name, "Ulysses L. Grant", that would have been a forgery, in the colloquial sense, because that was the name of of another living person (I think - someone who's already dead is not a "person"). In technical legal terms, "forgery" refers to a criminal offense involving documents that have some value, such as bank checks, wills, deeds, and such.

The program detects alterations. I think someone claiming to have a photo of a shark swimming in a pool when it was photoshopped in could be considered forgery couldn't it?

Well, not by my lights. I'd have said, "faked", I think. But thanks for that explanation.

[Tesla]

Cool! I don't care what they call it.

[photogem]

Image-forgery is well described here:
Comparative Study of Image Forgery and Copy-Move Techniques | SpringerLink

On page 716 one can see a good sample and the two different approaches, i.e. active vs. passive.
Passive approach includes "tampering".

Image forgery is a well known but in Wikipedia it is called photograph manipulation.
I think "RETOUCHING" would be the best name, but the word "PHOTOSHOPPED" became quite popular due to the well know program.


But they gave their program their name and yet, when something is found it says:
"this image may have been tampered with".

I had a good friend who was a learned "Retoucher" (Retuscheur in German).
For a long time it was that very intensive work with the airbrush-gun, his main work was advertising.
Then came Adobe PS which changed everything.
Work with the airbrush-gun stayed for those who for example worked on cars but he did courses with all the computer-programs,
but all the sudden cheap competition was available, very difficult to earn one's living.

Anyway, through him I had learned to work with Adobe PS (it was then PS7 which I had started with, later came CS2 which I still use at times because it is very small compared to CC2017. One of my sons studied Media-Art+Design. The way he is able to use PS again and again stuns me, I feel like a shirt-button on his shirt.

A well known tool is the "clone stamp tool".

If you enlarge your photo right down to pixel size, it is possible to manipulate right down on that level.

And yet, traces you cannot see remain and this program can detect such manipulations.

Basically it was Adam who recommended this program and I tried it out but came to a point where it wouldn't work anymore.

So I contacted this person who writes computer programs and is very fit with Linux.
Within a short time he had repaired it and made it public.

I had asked him if he would be able to write a firmware for the K5 series to allow KAF4 lenses but found out it would take ages,
he isn't into photography at all, his work is on very different fields, were is is one of very few.

[Racer X 69]

"Forgery" is the act of impersonating another in the production of a document, particularly by signing a name other than one's own. So I'm not sure exactly what this program is actually doing in this context.

Forgery is a forged steel crankshaft in 4130 chromoly steel.

Forgery is a forged steel crankshaft in 4130 chromoly steel.

Exactly - that word is one of those that has acquired new meaning by metaphorical use. Such as the way "impact" no longer assumes either a direct object nor some kind of physical collision, and is used as a synonym for "affect".

[Racer X 69]

Exactly - that word is one of those that has acquired new meaning by metaphorical use. Such as the way "impact" no longer assumes either a direct object nor some kind of physical collision, and is used as a synonym for "affect".

English is such a complex language.

[swanlefitte]

A well known tool is the "clone stamp tool".

If you enlarge your photo right down to pixel size, it is possible to manipulate right down on that level.

And yet, traces you cannot see remain and this program can detect such manipulations.

Have you figured out what it will detect? I am curious if you had dead pixels and used the in camera program to "get rid of them", would this be detected. Or using fill to remove sensor dust spots from blurred sky, (I do this one all the time). Cloning one pixel vs cloning in a forest are very different intentions.
It is interesting to know there is manipulation but "ethical" manipulation and detected manipulation may overlap so much it produces very noisey info.

[photogem]

Have you figured out what it will detect? I am curious if you had dead pixels and used the in camera program to "get rid of them", would this be detected. Or using fill to remove sensor dust spots from blurred sky, (I do this one all the time). Cloning one pixel vs cloning in a forest are very different intentions.
It is interesting to know there is manipulation but "ethical" manipulation and detected manipulation may overlap so much it produces very noisey info.

It detects the parts that have been tampered with, example:

Then you get a sample of the CFA-Detection and of the Copy-move-Detection.

If you are seriously interested: DIY!