Hacker Factor - Digital image analysis and forensics

[str8thinker]

Hacker Factor, a leader in cutting edge computer forensics research, provides custom software and services with a security focus to business customers.

About Dr. Neal Krawetz
Neal Krawetz earned his Ph.D. in Computer Science from Texas A&M University and Bachelors degree in Computer and Information Science from the University of California, Santa Cruz. In 2002, he founded Hacker Factor Solutions (www.hackerfactor.com) where he specializes in non-classical computer forensics, online profiling, and computer security. His research into anti-anonymity technologies combines fields as vast as ergonomics and child development to artificial intelligence and theoretical biophysics. He is the author of three books and numerous articles, and is a popular speaker at local and national conferences. His work experience spans small startup companies, academic and university environments, and large Fortune-100 corporations.

Since it's of great importance to us here to distinguish original images from digitally altered ones, Neal has kindly provided a white paper, A Picture's Worth: Digital Image Analysis and Forensics, to introduce us to the principles involved. It is listed on his Publications page, along with other interesting stuff. His Blog is also worth a visit.

While the paper is somewhat technical in places, Neal offers a number of commonsense tips to discern the authentic image from the bogus:

• Specular highlights and shadows. Sharp highlights and shadows indicate light direction. When items are merged into one picture, they may not have the same lighting.

• Color tones in anti-aliasing. Images rarely have sharp, crisp edges. Instead, anti-aliasing techniques blur adjacent colors together. When an object is cut out of one picture and pasted into another, the edges may contain coloring that does not match the new background.

• Reflections. When images are (Photo)shopped, reflections may not be modified. For example, a removed object may still be present in a reflection. Similarly, an added object may be missing within a reflection.

• Scale. When images are combined, they may not be at the correct scale.

• Roots. People or objects spliced into an image may appear to be “floating” (not rooted to the ground).

• Items. Common items in the image may be regional or time-specific. For example, electrical outlets differ by continent. Text and currency in an image may identify a location. And clocks and calendars disclose time. Similarly, photos that show computer screens may display a specific application, operating system, or recognizable web site.

• Duplication. Items within the picture may be copied and duplicated in other locations around the image. The duplications may be unmodified, scaled, rotated, flipped, or otherwise manipulated.

Unfortunately, many items cannot be clearly recognized without enhancing the image. Basic image enhancement methods can clarify elements within a picture for easier identification.

In 2006, Andrea Bertaccini was awarded the “CG Choice Award” from the CG Society for the rendering of Buzz Aldrin’s famous moonwalk (above, left). According to the artist, the picture was based the original NASA photo (above, right). However, details within the picture suggest additional resources (see paper).

Neal also includes advanced techniques such as Principal Component Analysis.

This is a tantalizing insight into a rapidly advancing technology.

See also:

Body by Victoria
(Photoshop Disasters recently featured a wonderfully horrible image from Victoria's Secret.)

Gender Guesser
(The words you use can disclose identifying features. This tool attempts to determine an author's gender based on the words used.)

[Dragonfly]

Thank you Str8thinker - this is an interesting, important, but also complex topic in the age of multimedia & digitalisation. I'm familiar with Image analysis.
I am not scared of people with low level photoshop skills. But we have to keep in mind, there are a lot of people with very high developed photoshop skills. How would you handle this problem? Of course I could ask my higher self, but how do I approach from the technical side?

Kind regards, Dragonfly

[str8thinker]

How would you handle this problem?

Apologies if I appeared to pass myself off as someone with such skills. Far from it. It must take a lot of time and effort to gain expertise in image forensics - each photo requires a lot of time to test. Reminds me of this guy's work on identifying the mysterious Louisiana creature. We need people like him here!

(I'm sure I've seen similar image analysis posts here at PA but can't recall where)

PS There was a recent post about a UFO sighted in Czechoslovakia which got posted on YouTube as "U.F.O. During Moldova TV News, Eastern Europe, 2008. AWESOME". Bill Ryan commented on the photographic aspects of that one. I can't find the PA thread containing it anywhere. That's a good candidate for this kind of analysis. Can anyone help me locate it?

[Dragonfly]

No probs str8thiner! Excellent you brought this issue to the table IMO. The awareness not to blindly believe in contents and depictions should increase more and more.

[noxon medem]

Posted by str8thinker (here)
PS. There was a recent post about a UFO sighted in Czechoslovakia which got posted on YouTube as "U.F.O. During Moldova TV News, Eastern Europe, 2008. AWESOME". Bill Ryan commented on the photographic aspects of that one. I can't find the PA thread containing it anywhere. That's a good candidate for this kind of analysis. Can anyone help me locate it?

- You find it on this thread: Probable Fake...Gulf of Aden??
https://projectavalon.net/forum4/show.....Gulf-of-Aden
Thread Opening Post is about a different videoclip, that seems to be a mystery solved now.
" U.F.O. Wormhole or "Optical illusion" !? Unknown Source."
https://youtube.com/watch?v=Upvca...layer_embedded
Bill Ryan commented on a photographic aspect of that one, and on different aspects concerning the one you mention,
https://youtube.com/watch?v=se0AfvfNXb0
that is introduced in post #7, and has started a parallell interesting debate (investigation) on the thread.

[str8thinker]

thanks noxon medem, that's the one.