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Old 09-04-2010, 08:05 PM
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Bassnut (Fred)
Narrowfield rules!

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Join Date: Nov 2006
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Quote:
Originally Posted by avandonk View Post
OK there are a few factors at work here. By dithering you immediately improve your resolution by a factor of one over root two. This is due to oversampling. More frames better definition.

By upsizing (always use bicubic) before stacking you will get better resolution merely because the arithmetic is better. Note dithering when collecting is what makes this work.


The lens has far better resolution than the sensor so we are only getting back something that already exists. You cannot make a lousy optic better.


I could go further but you get the idea. With star reduction algorithms and RL enhancement we have made the blocky 12.7 MP sensor perform
like a 64MP sensor.

All of this is mathematically valid.

It is the oversampling that is the secret. Not only does it increase signal to noise but resolution as well.

Bert
Yes, I would like the math Bert, even though I will struggle with it.

Dithering, as I understand, is primarily to eliminate sensor defects.

Even if you upsample, stacking will just align subs (canceling the dither)and produce the same results as a no-fault sensor sub.

I see dithering increasing res as say if a sub was captured at 4 times (or more) the image res to a fixed non-dithered file so that sub pixels "filled up" a larger pixel space, which is not possible now (that I know of).

Not doubting your math Bert, just asking
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