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Old 8th January 2010, 09:11   #45  |  Link
knutinh
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Join Date: Sep 2006
Posts: 42
Quote:
Originally Posted by MfA View Post
Not exactly, because generally we don't use brickwall filters in video filtering ... just for instance a simple 1/4, 1/2, 1/4 filter will let such high frequency line patterns through attenuated. You can't exactly say it leaves resolution intact though.
I was under the impression that such filtering was not possible in the sensor itself. If my sources are right that this sensor is native 60i, then it seems that electronic filtering will either be [1, 1]/2, or none. As for OLPF and optic flaws my knowledge is worse.

A tent filter will still have considerable attenuation above its cutoff frequency. If the measurement technique is good, then quoted line-pairs (or whatever) should be representative of the real frequency response, should it not?

Quote:
PS. if you are going to ignore my argument of vertical resolution in the presence of vertical motion don't quote it ...
I am not ignoring it. But for resolution in static scenes it is irrelevant. The question is to what degree cameras employ static filtering (for combating issues with movement) that also degrade the resolution in non-moving scenes. The answer seems to be that both are possible, like I said a few posts ago:
Quote:
Originally Posted by knutinh
To complicate matters further, different cameras construct the two video fields in different manners. In some cameras the even field corresponds to the even lines of pixels in the CCD chip, and the odd field to the odd lines of pixels in the CCD chip.
...
Slightly better are cameras which produce an average of the even lines and the preceding odd lines for the even field, and the odd lines and the preceding even lines for the odd field.
If you lookup that post you will see that I supply urls.

-k

Last edited by knutinh; 8th January 2010 at 09:15.
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