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.\" RCSid "$Id: pdfblur.1,v 1.3 2005/01/18 01:37:43 greg Exp $" |
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.TH PDFBLUR 1 1/24/96 RADIANCE |
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.SH NAME |
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pdfblur - generate views for depth-of-field blurring |
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.SH SYNOPSIS |
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.B pdfblur |
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.B aperture |
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.B nsamp |
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.B viewfile |
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.SH DESCRIPTION |
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.I Pdfblur |
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takes the given |
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.I viewfile |
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and computes |
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.I nsamp |
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views based on an aperture diameter of |
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.I aperture |
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(in world coordinate units) and a focal distance equal to the length of the |
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.I \-vd |
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view direction vector. |
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When rendered and averaged together, these views will result in |
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a picture with the specified depth of field. |
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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 viewfile |
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must also be passed on the command line to the chosen renderer, since |
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.I pdfblur |
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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 pdfblur |
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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, a single picture with z-buffer is all that is required |
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to get a satisfactory result, though the perfectionist may wish to |
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apply three pictures arranged in a triangle about the aperature, or |
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alternatively 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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(The latter may actually work out to be faster, since rendering |
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three views takes three times as long as a single view, and the |
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.I \-fr |
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option will end up recomputing relatively few pixels by |
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comparison.)\0 |
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.PP |
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To use |
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.I pdfblur |
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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 pdfblur. |
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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 larger aperatures. |
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.PP |
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The |
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.I \-pd |
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option of |
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.I rpict |
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may be used instead or in combination with or instead of |
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.I pdfblur |
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to blur depth-of-field. |
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If used in combination, |
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it is best to set the |
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.I \-pd |
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option to the overall |
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.I aperture |
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divided by |
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.I nsamp |
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to minimize ghosting in the output. |
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.SH EXAMPLES |
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To use |
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.I pinterp |
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to simulate an aperture of 0.5 inches on a lens focused at a |
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distance of 57 inches: |
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.IP "" .2i |
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rpict -vf myview -x 640 -y 480 -z orig.zbf scene.oct > orig.pic |
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.br |
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pdfblur 0.5 57 8 orig.pic | pinterp -B -vf orig.pic -x 640 -y 480 |
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orig.pic orig.zbf > blurry.pic |
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.PP |
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To use |
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.I rpict |
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exclusively to do the same: |
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.IP "" .2i |
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pdfblur .5 57 5 myview | rpict -S 1 -vf myview -x 640 -y 480 |
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-o view%d.pic scene.oct |
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.br |
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pcomb -s .2 view1.pic -s .2 view2.pic -s .2 view3.pic -s .2 |
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view4.pic -s .2 view5.pic > blurry.pic |
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.SH AUTHOR |
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Greg Ward |
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.SH BUGS |
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This program really only works with perspective views. |
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.SH "SEE ALSO" |
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pcomb(1), pinterp(1), pmblur(1), pmdblur(1), rcalc(1), rpict(1), vwright(1) |