[opendtv] Re: Mediaflo Technology

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Mon, 13 Nov 2006 11:12:36 -0500

At 10:36 AM -0500 11/13/06, Mark Schubin wrote:
I'll make more slides when I get a chance, but be aware that there are many interacting parameters:

- increase the samples on an imager and you can use less-restrictive filtering, so MTF goes up, but, if imager size is not increased, the line pairs/mm goes up, too, so lens-based and diffraction-based MTF go down - increase imager size, and lp/mm goes down, so diffraction-based MTF goes up, but aperture probably goes down, so diffraction-based MTF goes down (not to mention lens weight issues) - increase individual sensor size, and dynamic range goes up, but, if done with pixel offset as in the AG-HVX200, the possibility of color aliasing increases; large sensor sites also introduce aliasing if the sensor size doesn't match the desired pixel size (for which the optical filtering should be designed)

There's much more. Microlenses work great at narrow apertures but poorly at wide apertures. Larger imagers can cause vignetting at wide focal lengths (as on the Dalsa Origin).

I'll try to put more together when I get a chance. I'm afraid there's no "the rest of the story," only "more of the story."


Thanks Mark.

Obviously there are many variables at work here.

There is one area that might yield some interesting results in the short term.

Perhaps you could focus on the cameras that are shooting with 2/3 inch CCD sensors with 2 Mpixel resolution and determine the relative MTF of 1920 x 1080 versus 1280 x 720, as produced by the same camera with the same lens.


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