man/man1/pdfblur.1

.\" RCSid "$Id: pdfblur.1,v 1.4 2005/01/18 03:59:40 greg Exp $"
.TH PDFBLUR 1 1/24/96 RADIANCE
.SH NAME
pdfblur - generate views for depth-of-field blurring
.SH SYNOPSIS
.B pdfblur
.B aperture
.B nsamp
.B viewfile
.SH DESCRIPTION
.I Pdfblur
takes the given
.I viewfile
and computes
.I nsamp
views based on an aperture diameter of
.I aperture
(in world coordinate units) and a focal distance equal to the length of the
.I \-vd
view direction vector.
When rendered and averaged together, these views will result in
a picture with the specified depth of field.
Either
.I pinterp(1)
or
.I rpict(1)
may be called to do the actual work.
(The given
.I viewfile
must also be passed on the command line to the chosen renderer, since
.I pdfblur
provides supplemental view specifications only.)\0
.PP
For
.I pinterp,
feed the output of
.I pdfblur
to the standard input of
.I pinterp
and apply the
.I \-B
option to blur views together.
In most cases, a single picture with z-buffer is all that is required
to get a satisfactory result, though the perfectionist may wish to
apply three pictures arranged in a triangle about the aperature, or
alternatively apply the
.I \-ff
option together with the
.I \-fr
option of
.I pinterp.
(The latter may actually work out to be faster, since rendering
three views takes three times as long as a single view, and the
.I \-fr
option will end up recomputing relatively few pixels by
comparison.)\0
.PP
To use
.I pdfblur
with
.I rpict,
apply the
.I \-S
option to indicate a rendering sequence, and set the
.I \-o
option with a formatted file name to save multiple output
pictures.
When all the renderings are finished, combine them with the
.I pcomb(1)
program, using appropriate scalefactors to achieve an average.
Note that using
.I rpict
is MUCH more expensive than using
.I 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).
.PP
For both
.I pinterp
and
.I rpict,
the computation time will be proportional to the number of views from
.I pdfblur.
We have found a
.I nsamp
setting somewhere between 5 and 10 to be adequate for most images.
Relatively larger values are appropriate for larger aperatures.
.PP
The
.I \-pd
option of
.I rpict
may be used instead or in combination with or instead of
.I pdfblur
to blur depth-of-field.
If used in combination,
it is best to set the
.I \-pd
option to the overall
.I aperture
divided by
.I nsamp
to minimize ghosting in the output.
.PP
To simulate a particular camera's aperture, divide the focal length of
the lens by the f-number, then convert to the corresponding
world coordinate 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.
.SH EXAMPLES
To use
.I pinterp
to simulate an aperture of 0.5 inches on a lens focused at a
distance of 57 inches:
.IP "" .2i
rpict -vf myview -x 640 -y 480 -z orig.zbf scene.oct > orig.pic
.br
pdfblur 0.5 57 8 orig.pic | pinterp -B -vf orig.pic -x 640 -y 480
orig.pic orig.zbf > blurry.pic
.PP
To use
.I rpict
exclusively to do the same:
.IP "" .2i
pdfblur .5 57 5 myview | rpict -S 1 -vf myview -x 640 -y 480
-o view%d.pic scene.oct
.br
pcomb -s .2 view1.pic -s .2 view2.pic -s .2 view3.pic -s .2
view4.pic -s .2 view5.pic > blurry.pic
.SH AUTHOR
Greg Ward
.SH BUGS
This program really only works with perspective views.
.SH "SEE ALSO"
pcomb(1), pinterp(1), pmblur(1), pmdblur(1), rcalc(1), rpict(1), vwright(1)
Revision:	1.5
Committed:	Tue Jan 18 20:19:56 2005 UTC (20 years, 9 months ago) by greg
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad3R8
Changes since 1.4:	+8 -1 lines
Log Message:	Added example aperture calculation
#	User	Rev	Content
1	greg	1.5	.\" RCSid "$Id: pdfblur.1,v 1.4 2005/01/18 03:59:40 greg Exp $"
2	greg	1.1	.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	greg	1.3	views based on an aperture diameter of
17	greg	1.1	.I aperture
18	greg	1.3	(in world coordinate units) and a focal distance equal to the length of the
19			.I \-vd
20			view direction vector.
21	greg	1.1	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	greg	1.3	.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	greg	1.5	.PP
106			To simulate a particular camera's aperture, divide the focal length of
107			the lens by the f-number, then convert to the corresponding
108			world coordinate units.
109			For example, if you wish to simulate a 50mm lens at f/2.0 in
110			a scene modeled in meters, then you divide 50mm by 2.0 to get 25mm,
111			which corresponds to an effective aperture of 0.025 meters.
112	greg	1.1	.SH EXAMPLES
113			To use
114			.I pinterp
115			to simulate an aperture of 0.5 inches on a lens focused at a
116			distance of 57 inches:
117			.IP "" .2i
118			rpict -vf myview -x 640 -y 480 -z orig.zbf scene.oct > orig.pic
119			.br
120			pdfblur 0.5 57 8 orig.pic \| pinterp -B -vf orig.pic -x 640 -y 480
121			orig.pic orig.zbf > blurry.pic
122			.PP
123			To use
124			.I rpict
125			exclusively to do the same:
126			.IP "" .2i
127			pdfblur .5 57 5 myview \| rpict -S 1 -vf myview -x 640 -y 480
128			-o view%d.pic scene.oct
129			.br
130			pcomb -s .2 view1.pic -s .2 view2.pic -s .2 view3.pic -s .2
131			view4.pic -s .2 view5.pic > blurry.pic
132			.SH AUTHOR
133			Greg Ward
134			.SH BUGS
135			This program really only works with perspective views.
136			.SH "SEE ALSO"
137	greg	1.4	pcomb(1), pinterp(1), pmblur(1), pmdblur(1), rcalc(1), rpict(1), vwright(1)