Secure Computing: Sec-C

(I'm actually surprised that more than 12 people are reading my blog.)

In my last posting I mentioned about the frozen-video and how nothing indicates that Bin Laden is alive today. This was done with video and audio analysis. However, a couple of people have written to me and asked about the image analysis.

As far as my tools can detect, there has been no image manipulation of the Bin Laden portion of the image beyond contrast adjustment. His beard really does appear to be that color. (I've asked another graphics researcher to also look at the image I analyzed, as a cross-check.)

One of the limitations of image analysis is that staged environments are not digital fakes. For example, when China Airlines painted over their logo on crashed planes, the pictures did not analyze as being faked -- because they were not. In the case of his beard, it could be a costume mask, or a trimmed and dyed beard.

Another limitation concerns image size and resaves. If you make a picture small enough or resave it many times, then the fine details vanish. A picture that looks obviously like a fake cannot be detected as being a fake.

With regards to Bin Laden's beard... It cannot be detected with any of my tools as being digitally modified. However:

• The whole inner frame of Bin Laden was resaved at least twice. The number of reseaves does not appear to be enough to distort significant modifications.
  
  
• The colorful border was also saved twice. However...
  
  
• Even though the Bin Laden frame and border were both saved twice each, they were not saved at the same time. I know this because the Jpeg artifacts (8x8 squares) are on the 8x8 grid for the Bin Laden frame, but are shifted over on the border -- the border's 8x8 artifacts do not lie on the Jpeg 8x8 grid.
  
  
• The whole video frame (border + Bin Laden) was combined from many parts. Here's the order, starting with the last thing added:
  
  1. As-Sahab logo, English subtitles, and text below Bin Laden (alternates between English and Arabic) was added last.
     
  2. "The Solution" and Arabic in the top right corner was the penultimate addition.
     
  3. The Bin Laden frame and border were combined.
     
  4. In the Bin Laden frame, there is no indication of manipulation and no indication of a chromakey replacement. In the border, the spinning globe was modified along with the strobing colors.
  
  
• Both saturation and PCA shows fine horizontal stripes on Bin Laden and the background. These came from interlaced video sources. In contrast, the text elements and As-Sahab logo appear to be from non-interlaced sources.

My findings are certainly not perfect. I just got the results from a blind test for image analysis. My overall accuracy was 84%. For the question, "Is it computer graphics (CG)?", my tools and methods had 0% false-positives (no claims that a real image is CG), and 27% false-negatives where I claimed the image was real but it was really CG. And most of the false-negatives were award winners from the CG Society; it is a good thing most regular people don't have this kind of artistic skill. Ignoring the CG Society's award winners, my accuracy was in the 90 percentile, but there is always room for error.

As for the video and audio analysis: there is no error. The splices are real, and the video does not appear to show any recent indication of Osama Bin Laden being alive today.

In my last posting, I said that Osama is as alive as Elvis. Hyperqube had a better analogy: Osama is as alive as that dude from Weekend at Bernie's.