London bombers, the conspiracies begin *sigh*

I’m loath to give publicity to this, but the pit would make no sense without the link. Plus, it’s good for a damn good laugh (and will probably crop up in GQ at some point)…

It’s a video tape!!! Things don’t appear as they should!! Have you any evidence of the medium this was recorded on, and what has subsequently happened to it? No. Better than that, you treat the image to your CSI-level genius via “magnification in Photoshop”. Thanks. Because that makes all the difference. You’ve heard of resampling, I presume? You know, the default setting in Photoshop, where it adds pixels to fill in the gaps?

And the last picture is pure genius. I applaud you.

That whole site makes me twitch.

I haven’t been that paranoid since I ran that 9 month fever. :smack:

And why aren’t the stars visible?

GorillaMan, there is one sentence from your link with which I can half-agree, and that is where he says:

[I agree with the first half. He’s no image specialist.]

IMHO, the crucial phrase in your OP is:

Whereas I have no particular knowledge of the exact compression algorithms used in the CCTV camers at Luton Station, I do have some experience with video image compression and manipulation.

Good old-fashioned analog video signals used to be recorded on videotape (or, if appropriate, broadcast over the airwaves), with a storage capacity / bandwidth dependent on the spatial resolution, framerate, and intensity depth (including color information). This method could be made fairly free of artifacts, but consumed a large storage capacity or bandwidth for the resulting quality.

In the realm of digital video, compression is used to minimize the storage and/or bandwidth requirements while maintaining the desired image quality. Without this technology, we wouldn’t have DVDs or streaming media. One of the most frequently-used video compression methods is to use key frames and delta frames. Key frames are sent every nth frame, and provide intensity information for every single pixel in the original image coming from the camera sensor (CCD or CMOS). The remaining frames are delta frames (also called P-frames or B-frames in different naming conventions), which provide information only on those pixels whose intensities have changed since the last key frame. Much of the advances in video compression involve determining how often to send key frames, and development of (often very different) algorithms for key frame compression and delta frame compression.

Closed-Circuit Television (CCTV) cameras, such as those in the OP’s link for the Luton Station CCTV, are ideally suited for video compression. Although some of them have pan/scan/zoom capabilities, most unattended ones are focussed on a static image field. Thus, key frames can be recorded fairly infrequently, and most information is in the delta frames, which show the movement of people. In addition, there is a huge incentive to reduce the data rate, since one wants to be able to store CCTV video images for several days per camera location, and it could potentially involve hundreds of gigabytes per day for a multi-camera site.

The more agressive the algorithm used to reduce the data rate, the more likely it is that “artifacts” will enter the video image, and the most common artifact found is often a ghost from the most-recent key image. In many cases, this means that images of static objects appear mixed in with the live image.

The above artifact problem can get worse if one does post-acquisition processing on certain “regions of interest” (ROI), at the expense of the rest of the image. It is entirely possible that, while enhancing the image of the guy with the backpack in the foreground of the Luton image, various key+delta frames were added together. If “backpack kid” and “white hat” were walking at different speeds, it wouldn’t be unexpected to find that image enhancement of the former causes the latter to get a railing through his head. It’s also possible that image enhancement of “white hat” would cause “backpack boy” to grow a second head.

The ideal soultion would be to record all parts of the image at maximum frame-rate, but that makes storage of the information prohibitably expensive. Since we can’t get at the raw image from the camera, I would at least want to see the various “key” and “delta” frames before claiming that someone is inserting phantom characters.

There’s also the point that, if you’re going to go to the trouble to insert a person into the image, wouldn’t you do a better job of it than the OP’s link photo shows?

[My credentials? I’m currently working on an imaging application in which the information from a high-resolution, high-framerate camera is compressed to allow streaming broadcast of sporting events that have previously been considered difficult to broadcast via TV.]

It seems to me that it would actually take more effort to make it appear that the “added” man is partly behind the railing.

“Hmmm…this doctored photo looks too realistic to be real…I’d better make it look less real, otherwise people won’t think it’s real.” Or something like that.

I think you might be on to something, Mbossa

The very fact that the forgers included the anomalies Antonius Block described shows that they were experts with an intimate knowledge of the system in question…huzzah, it’s further proof that it’s a fake!..
I’m off to buy stocks in tin foil :smiley:

So let’s think about this: you have a photo and you’re adding “white hat”. So you cut out “white hat” from some other image and you put him into the photo. Clearly, you put him in so that he is layered in front of the background, including (for the most part) the railing.

How does the railing get in front of his arm? There’s only two possibilities. One, for some bizzaro reason you actually go to special effort to layer the railing in front of his arm but behind the rest of him. Which is clearly crap. Or two, the railing is in front of his arm through some form of optical illusion or video artefact.

No brainer.

Or, on preview, what Mbossa said.

Should we tell Mr. Delusional that white hat’s left arm is bent and holding his backpack strap?

Did you look at the ‘shop’ on that website?
The horror…the horror…

Funny thing is, it WAS all a conspiracy. Just like the Lincoln assassination and 9/11. Thing is, we know exactly who, why, and how did all those things. 7/21 they’re still working on. The site seems to think that only governments can have the good conspiracies, which seems unfair.