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root/radiance/ray/doc/man/man1/pdfblur.1
Revision: 1.3
Committed: Tue Jan 18 01:37:43 2005 UTC (19 years, 4 months ago) by greg
Branch: MAIN
Changes since 1.2: +21 -6 lines
Log Message:
Eliminated redundant specification of focal distance in pdfblur

File Contents

# Content
1 .\" RCSid "$Id: pdfblur.1,v 1.2 2003/12/09 15:59:06 greg Exp $"
2 .TH PDFBLUR 1 1/24/96 RADIANCE
3 .SH NAME
4 pdfblur - generate views for depth-of-field blurring
5 .SH SYNOPSIS
6 .B pdfblur
7 .B aperture
8 .B nsamp
9 .B viewfile
10 .SH DESCRIPTION
11 .I Pdfblur
12 takes the given
13 .I viewfile
14 and computes
15 .I nsamp
16 views based on an aperture diameter of
17 .I aperture
18 (in world coordinate units) and a focal distance equal to the length of the
19 .I \-vd
20 view direction vector.
21 When rendered and averaged together, these views will result in
22 a picture with the specified depth of field.
23 Either
24 .I pinterp(1)
25 or
26 .I rpict(1)
27 may be called to do the actual work.
28 (The given
29 .I viewfile
30 must also be passed on the command line to the chosen renderer, since
31 .I pdfblur
32 provides supplemental view specifications only.)\0
33 .PP
34 For
35 .I pinterp,
36 feed the output of
37 .I pdfblur
38 to the standard input of
39 .I pinterp
40 and apply the
41 .I \-B
42 option to blur views together.
43 In most cases, a single picture with z-buffer is all that is required
44 to get a satisfactory result, though the perfectionist may wish to
45 apply three pictures arranged in a triangle about the aperature, or
46 alternatively apply the
47 .I \-ff
48 option together with the
49 .I \-fr
50 option of
51 .I pinterp.
52 (The latter may actually work out to be faster, since rendering
53 three views takes three times as long as a single view, and the
54 .I \-fr
55 option will end up recomputing relatively few pixels by
56 comparison.)\0
57 .PP
58 To use
59 .I pdfblur
60 with
61 .I rpict,
62 apply the
63 .I \-S
64 option to indicate a rendering sequence, and set the
65 .I \-o
66 option with a formatted file name to save multiple output
67 pictures.
68 When all the renderings are finished, combine them with the
69 .I pcomb(1)
70 program, using appropriate scalefactors to achieve an average.
71 Note that using
72 .I rpict
73 is MUCH more expensive than using
74 .I pinterp,
75 and it is only recommended if the scene and application
76 absolutely demand it (e.g. there is prominent refraction that
77 must be modeled accurately).
78 .PP
79 For both
80 .I pinterp
81 and
82 .I rpict,
83 the computation time will be proportional to the number of views from
84 .I pdfblur.
85 We have found a
86 .I nsamp
87 setting somewhere between 5 and 10 to be adequate for most images.
88 Relatively larger values are appropriate for larger aperatures.
89 .PP
90 The
91 .I \-pd
92 option of
93 .I rpict
94 may be used instead or in combination with or instead of
95 .I pdfblur
96 to blur depth-of-field.
97 If used in combination,
98 it is best to set the
99 .I \-pd
100 option to the overall
101 .I aperture
102 divided by
103 .I nsamp
104 to minimize ghosting in the output.
105 .SH EXAMPLES
106 To use
107 .I pinterp
108 to simulate an aperture of 0.5 inches on a lens focused at a
109 distance of 57 inches:
110 .IP "" .2i
111 rpict -vf myview -x 640 -y 480 -z orig.zbf scene.oct > orig.pic
112 .br
113 pdfblur 0.5 57 8 orig.pic | pinterp -B -vf orig.pic -x 640 -y 480
114 orig.pic orig.zbf > blurry.pic
115 .PP
116 To use
117 .I rpict
118 exclusively to do the same:
119 .IP "" .2i
120 pdfblur .5 57 5 myview | rpict -S 1 -vf myview -x 640 -y 480
121 -o view%d.pic scene.oct
122 .br
123 pcomb -s .2 view1.pic -s .2 view2.pic -s .2 view3.pic -s .2
124 view4.pic -s .2 view5.pic > blurry.pic
125 .SH AUTHOR
126 Greg Ward
127 .SH BUGS
128 This program really only works with perspective views.
129 .SH "SEE ALSO"
130 pcomb(1), pinterp(1), pmblur(1), rcalc(1), rpict(1), vwright(1)