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. Regards Craig ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.