Radiance pmdblur program

PMDBLUR(1)                                                          PMDBLUR(1)

NAME

       pmdblur - generate views for combined camera motion and depth blurring

SYNOPSIS

       pmdblur speed aperture nsamp v0file v1file

DESCRIPTION

       Pmdblur  takes  two  viewfiles  and generates nsamp views starting from
       v0file and moving towards v1file, simulating an  aperture  of  diameter
       aperture  in  world  coordinate  units.   When  rendered  and  averaged
       together, these views will result in a picture with motion  and  depth-
       of-field blur due to a camera changing from v0 to v1 in a relative time
       unit of 1, whose shutter is open starting at v0 for speed of these time
       units.   Either  pinterp(1)  or rpict(1) may be called to do the actual
       work.  (The given v0file must also be passed on the command line to the
       chosen  renderer,  since  pmdblur provides supplemental view specifica-
       tions only.)

       For pinterp, feed the output of pmdblur to the standard input  of  pin-
       terp  and  apply  the -B option to blur views together.  In most cases,
       two pictures with z-buffers at  v0  and  v1  will  get  a  satisfactory
       result,  though  the  perfectionist  may  wish  to apply the -ff option
       together with the -fr option of pinterp.

       To use pmdblur with rpict, apply the -S option to indicate a  rendering
       sequence, and set the -o option with a formatted file name to save mul-
       tiple output pictures.  When all the renderings are  finished,  combine
       them  with  the  pcomb(1)  program,  using  appropriate scalefactors to
       achieve an average.  Note that using rpict is MUCH more expensive  than
       using  pinterp, and it is only recommended if the scene and application
       absolutely demand it (e.g. there is prominent refraction that  must  be
       modeled accurately).

       For  both  pinterp and rpict, the computation time will be proportional
       to the number of views from pmdblur.  We have  found  a  nsamp  setting
       somewhere  between 7 and 15 to be adequate for most images.  Relatively
       larger values are appropriate for faster camera motion.

       The -pm and/or -pd options of rpict may be used instead or in  combina-
       tion  to  blur  animated  frames,  with the added advantage of blurring
       reflections and refractions according to their proper motion.  However,
       this  option  will  result in more noise and expense than using pmdblur
       with pinterp as a post-process.  If both blurring methods are  used,  a
       smaller  value  should  be  given  to the rpict -pm option equal to the
       shutter speed divided by the number of  samples,  and  the  -pd  option
       equal  to  the aperture divided by the number of samples.  This will be
       just enough to blur the boundaries of the ghosts which may appear using
       pmdblur with a small number of time samples.

       To  simulate a particular camera's aperture, divide the focal length of
       the lens by the f-number, then convert to the corresponding world coor-
       dinate  units.   For  example,  if  you wish to simulate a 50mm lens at
       f/2.0 in a scene modeled in meters, then you divide 50mm by 2.0 to  get
       25mm, which corresponds to an effective aperture of 0.025 meters.

EXAMPLES

       To  use  pinterp  to simulate motion blur between two frames of a walk-
       through animation, where the camera shutter is  open  for  1/4  of  the
       interframe distance with an aperture of 0.1 world units:

         pmdblur .25 .1 8 fr1023.hdr fr1024.hdr | pinterp -B -vf fr1023.hdr -x
         640 -y 480 fr1023.hdr fr1023.zbf fr1024.hdr fr1024.zbf > fr1023b.hdr

AUTHOR

       Greg Ward

SEE ALSO

       pcomb(1),  pdfblur(1),  pinterp(1),  pmblur(1),   rcalc(1),   rpict(1),
       vwright(1)

RADIANCE                            1/17/05                         PMDBLUR(1)