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.\" RCSid "$Id" |
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.TH PMBLUR 1 3/3/98 RADIANCE |
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.SH NAME |
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pmblur - generate views for camera motion blurring |
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.SH SYNOPSIS |
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.B pmblur |
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.B speed |
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.B nsamp |
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.B v0file |
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.B v1file |
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.SH DESCRIPTION |
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.I Pmblur |
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takes two viewfiles and generates |
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.I nsamp |
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views starting from |
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.I v0file |
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and moving towards |
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.I v1file. |
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When rendered and averaged together, these views will result in |
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a picture with motion blur due to a camera changing from v0 to v1 |
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in a relative time unit of 1, whose shutter is open starting at v0 for |
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.I speed |
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of these time units. |
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Either |
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.I pinterp(1) |
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or |
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.I rpict(1) |
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may be called to do the actual work. |
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(The given |
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.I v0file |
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must also be passed on the command line to the chosen renderer, since |
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.I pmblur |
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provides supplemental view specifications only.)\0 |
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.PP |
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For |
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.I pinterp, |
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feed the output of |
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.I pmblur |
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to the standard input of |
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.I pinterp |
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and apply the |
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.I \-B |
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option to blur views together. |
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In most cases, two pictures with z-buffers at v0 and v1 will |
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get a satisfactory result, though the perfectionist may wish to |
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apply the |
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.I \-ff |
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option together with the |
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.I \-fr |
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option of |
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.I pinterp. |
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.PP |
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To use |
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.I pmblur |
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with |
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.I rpict, |
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apply the |
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.I \-S |
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option to indicate a rendering sequence, and set the |
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.I \-o |
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option with a formatted file name to save multiple output |
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pictures. |
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When all the renderings are finished, combine them with the |
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.I pcomb(1) |
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program, using appropriate scalefactors to achieve an average. |
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Note that using |
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.I rpict |
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is MUCH more expensive than using |
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.I pinterp, |
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and it is only recommended if the scene and application |
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absolutely demand it (e.g. there is prominent refraction that |
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must be modeled accurately). |
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.PP |
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For both |
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.I pinterp |
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and |
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.I rpict, |
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the computation time will be proportional to the number of views from |
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.I pmblur. |
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We have found a |
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.I nsamp |
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setting somewhere between 5 and 10 to be adequate for most images. |
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Relatively larger values are appropriate for faster camera motion. |
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.PP |
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The |
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.I \-pm |
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option of |
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.I rpict |
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may be used instead or in combination to blur animated frames, with |
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the added advantage of blurring reflections and refractions according |
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to their proper motion. |
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However, this option will result in more noise and expense than using |
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.I pmblur |
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with |
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.I pinterp |
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as a post-process. |
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If both blurring methods are used, a smaller value should be given to the |
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.I rpict |
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.I \-pm |
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option equal to the shutter speed divided by the number of pmblur views. |
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This will be just enough to blur the boundaries of the ghosts |
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which may appear using |
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.I pmblur |
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with a small number of time samples. |
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.SH EXAMPLES |
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To use |
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.I pinterp |
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to simulate motion blur between two frames of a walk-through |
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animation, where the camera shutter is open for 1/4 of the |
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interframe distance: |
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.IP "" .2i |
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pmblur .25 8 fr1023.pic fr1024.pic | pinterp -B -vf fr1023.pic -x 640 -y 480 |
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fr1023.pic fr1023.zbf fr1024.pic fr1024.zbf > fr1023b.pic |
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.SH AUTHOR |
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Greg Ward |
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.SH BUGS |
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Changes in the view shift and lift vectors or the fore and aft |
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clipping planes are not blurred. |
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.SH "SEE ALSO" |
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pcomb(1), pdfblur(1), pinterp(1), rcalc(1), rpict(1), vwright(1) |