Double/infinity exposure, image processing. - DSLR Hack development - CHDK Forum

Double/infinity exposure, image processing.

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Double/infinity exposure, image processing.
« on: 11 / May / 2011, 13:41:01 »
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Is it possible to double/multi expose already in the buffer? To somehow turn that thing off which says that when picture 1 and picture 2 blends together it is called double exposure. Why? Because it is totally fake and hasn't anything to do with double exposure. I don't know if any more modern Canon (from 400D) has a double exposure-function, but my hasn't one. Is it hard to make one?

And also take a look at the the "image processing" - see what really is happening. Has any of this been investigated?


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Offline a1ex

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Re: Double/infinity exposure, image processing.
« Reply #1 on: 12 / May / 2011, 04:28:26 »
So... what you want to say is... if you add two numbers right now, you get the correct result, and if you add them later, you get a fake result :)

Yes, double/multiple exposure means adding (or averaging) some image buffers, usually in RGB space. Probably it works in YUV too (didn't try).

Example (averaged 1800 movie frames in RGB):
http://dl.dropbox.com/u/4124919/long-exposure.jpg

It was done with a python script, from an 1-minute movie => it's totally fake.

Re: Double/infinity exposure, image processing.
« Reply #2 on: 12 / May / 2011, 15:49:24 »
So... what you want to say is... if you add two numbers right now, you get the correct result, and if you add them later, you get a fake result :)[/url]
Hehe, that's right! ;)
What I want to know if there is some kind of interesting information just going away/being compressed when the image is going to the image processing-thing. So that those two numbers has a lot of decimals which is chopped. What if we could take that information and do something with it.

Interesting example!

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Offline a1ex

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Re: Double/infinity exposure, image processing.
« Reply #3 on: 12 / May / 2011, 16:19:07 »
If you shoot RAW, there's nothing lost.


Re: Double/infinity exposure, image processing.
« Reply #4 on: 12 / May / 2011, 16:27:31 »
Does Focus peaking only work with Auto-focus lenses? None of my manual, converted lenses seem to work..

 

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