[opendtv] Re: Why Europe should choose 720P for HDTV

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx, Tom Barry <trbarry@xxxxxxxxxxx>
  • Date: Mon, 13 Dec 2004 10:14:31 -0500

At 1:17 PM -0800 12/11/04, Henry Baker wrote:
>I think that motion has the same effect as "raising the spatial frequency"
>of the picture, which means that the proper Nyquist filter has effectively
>a lower bandwidth.  The end result is that motion is inevitably more blurred
>than static pictures.
>I haven't seen any papers or books which provide a proper mathematical
>analysis of this effect, but I'm sure that they're out there somewhere.

This is very easy to understand. The appropriate amount of motion 
blur is directly related to the resolution of the source and the 
frame rate. And, if we are dealing with fields, then there must be 
additional filtering to deal with interlace.

As the frame rate decreases, the amount of blur in motion must 
increase to prevent the perception of motion discontinuity, which may 
manifest itself as a strobing effect or judder.

One must also consider the rates of pans and zooms as they relate to 
the frame rate. Cinematographers rarely zoom, but they pan and truck 
all the time, and they calculate the rates of movement to prevent or 
minimize the perception of motion artefacts.

Gary Demos has probably done some of the most extensive work in this areas.

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