PMDBLUR(1)                                                          PMDBLUR(1)



NNAAMMEE
       pmdblur - generate views for combined camera motion and depth blurring

SSYYNNOOPPSSIISS
       ppmmddbblluurr ssppeeeedd aappeerrttuurree nnssaammpp vv00ffiillee vv11ffiillee

DDEESSCCRRIIPPTTIIOONN
       _P_m_d_b_l_u_r  takes  two  viewfiles  and generates _n_s_a_m_p views starting from
       _v_0_f_i_l_e and moving towards _v_1_f_i_l_e_, simulating an  aperture  of  diameter
       _a_p_e_r_t_u_r_e  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 _s_p_e_e_d of these time
       units.   Either  _p_i_n_t_e_r_p_(_1_)  or _r_p_i_c_t_(_1_) may be called to do the actual
       work.  (The given _v_0_f_i_l_e must also be passed on the command line to the
       chosen  renderer,  since  _p_m_d_b_l_u_r provides supplemental view specifica-
       tions only.)

       For _p_i_n_t_e_r_p_, feed the output of _p_m_d_b_l_u_r to the standard input  of  _p_i_n_-
       _t_e_r_p  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 _-_f_f option
       together with the _-_f_r option of _p_i_n_t_e_r_p_.

       To use _p_m_d_b_l_u_r with _r_p_i_c_t_, 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  _p_c_o_m_b_(_1_)  program,  using  appropriate scalefactors to
       achieve an average.  Note that using _r_p_i_c_t is MUCH more expensive  than
       using  _p_i_n_t_e_r_p_, 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  _p_i_n_t_e_r_p and _r_p_i_c_t_, the computation time will be proportional
       to the number of views from _p_m_d_b_l_u_r_.  We have  found  a  _n_s_a_m_p  setting
       somewhere  between 7 and 15 to be adequate for most images.  Relatively
       larger values are appropriate for faster camera motion.

       The _-_p_m and/or _-_p_d options of _r_p_i_c_t 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 _p_m_d_b_l_u_r
       with _p_i_n_t_e_r_p as a post-process.  If both blurring methods are  used,  a
       smaller  value  should  be  given  to the _r_p_i_c_t _-_p_m option equal to the
       shutter speed divided by the number of  samples,  and  the  _-_p_d  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
       _p_m_d_b_l_u_r 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.

EEXXAAMMPPLLEESS
       To  use  _p_i_n_t_e_r_p  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

AAUUTTHHOORR
       Greg Ward

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



RADIANCE                            1/17/05                         PMDBLUR(1)
