Saturday, January 10, 2009

Limits in photography.


I originally took this photo because it was funny. The pedestrian crossing in the foreground was painted halfway across the road and stayed that way for weeks. In a strict interpretation of the law, the pedestrian has right of way to the middle of the road and after that, they're on their own. (I blurred out the car registration and the sign on the right, but that's the only modification).

It serves another purpose though. See the bus in the distance? Despite the original being a 10 megapixel image, it's not possible to read what it says on the bus destination board. If you enlarge it, you get this:


No matter how you enlarge or filter that image, all you see is a yellow blur. That's because digital images are built of pixels, and the number of pixels defines how far it can be enlarged. Keep going, and you'll get a lot of coloured squares.

A similar issue applies to real film cameras. They can produce much finer detail than digital, but the film has a grain made up of particles of silver nitrate, and there is a limit to enlargement. It depends on the ASA rating: film with finer grain produces better detail but needs more light to do it. So a 400 ASA photo will show grain if enlarged to 8x10 but will take photos in poor light. A 25 ASA slide film will give you images you can project on big screens, but needs very good lighting to produce those images.

Southern Writer sent me some links to a new process called Penetrating Photographic Process (here and here) and asked what I thought of it (well, I think she did it to get me moving again. The blog has been somewhat spartan of late - so thanks for the e-prod, SW ;)). My first impression of this process is that it's nothing more than an artefact generating system.

I am not saying the original UFO photos were faked. They might well be real. The second link does look especially impressive. What I take issue with is the enlargement of those images beyond the capabilities of cameras, whether film or digital. I think this penetrating photographic process is a load of hokum, but it's easy to prove me wrong.

Take that photo of the bus. It would require far less enlargement and processing than was used on those UFO photos. If you want me to believe that the penetrating photographic process has any basis in reality whatsoever, just tell me the destination and bus number in that yellow blur. Better yet, show the enhanced image that reveals the information.

Yes, I do know the answer. And no, I don't expect any PPP practitioner has ever validated their method on a mundane target such as this, even though it's the first thing any decent scientist would do.

Those running this process charge for their work. Before I'd be willing to pay out, I'd want to see some evidence that it works.

2 comments:

Southern Writer said...

Bravo! Well done. If I were offering the ten thousand dollar challenge, I would have to pay you. I thought, myself, that it was probably a case of pareidolia, which is something else I wish you'd discuss with us.




ver: loolaro

Of course it doesn't spell anything, but it should.

Romulus Crowe said...

Well, faces in clouds and so on are commonly seen because we're prorgrammed to look for faces. That's why I never say anything about the photos I put up - I want to see if anyone else sees what I see without prompting.

There's a sceptic site here that covers it:
http://skepdic.com/pareidol.html

I remember the 'bigfoot on mars' image. It was part of a much larger image, in which it's clear that the thing is just a few metres from the Rover's camera and would be about six inches tall.

The more vague images appear, the harder it is to find something that has any kind of definitive evidence to it. It can all be dismissed by a sceptic as pariedolic imagery.

Well, nobody said it would be easy.

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