man/man1/ra_rgbe.1

.\" RCSid "$Id: ra_rgbe.1,v 1.3 2024/09/10 20:24:42 greg Exp $"
.TH RA_RGBE 1 1/23/98 RADIANCE
.SH NAME
ra_rgbe - convert between different RADIANCE picture types
.SH SYNOPSIS
.B ra_rgbe
[
.B \-r
][
.B "\-e +/-stops"
][
.B \-f
][
.B "\-n frameno"
]
[
.B input
[
.B outspec
]
]
.SH DESCRIPTION
.I Ra_rgbe
converts between RADIANCE run-length encoded and flat formats, and
separates concatanated animation frames produced by
.I rpict(1).
The
.I \-e
option specifies an exposure compensation in f-stops (powers of two).
Only integer stops are allowed, for efficiency.
By default,
.I ra_rgbe
produces a flat RADIANCE picture file from any type of RADIANCE
input picture.
The
.I \-r
option causes
.I ra_rgbe
to produce a run-length encoded file instead.
.PP
If the input file consists of multiple animation frames as produced by
.I rpict
with the
.I \-S
option,
.I ra_rgbe
will read each frame and write it to the output file created by calling
.I printf(3)
with the output specification and frame number as arguments.
If the output specification begins with an exclamation mark ('!'),
then this interpreted as a command spec., which is also run through
.I printf
with the frame number to get the final command.
This command must accept a Radiance picture on its standard input,
and may write results either to a file or to the standard output.
The
.I \-n
option may be used to select a specific frame for output, and
other frames in the input will be skipped.
Normally, all frames will be read and written.
.PP
.I Ra_rgbe
will report an error and exit if the target output file already exists,
unless the
.I \-f
option is given.
If the output file is missing, the standard output is used.
If the input file is missing or set to '-', the standard input is used.
.SH NOTES
The file format for RADIANCE pictures was changed between release
1.4 and release 2.0.
The older format can still be read by all the programs, but only
the newer format is produced.
This newer format cannot be read by RADIANCE software prior to
release 2.0.
.PP
.I Ra_rgbe
provides some downward compatibility by producing files that can
be read by older RADIANCE software.
The resultant files are also easier to manipulate with programs
designed to read raw raster data.
.PP
The other use for
.I ra_rgbe
is as a quicker way to adjust the exposure of a RADIANCE picture than
.I pfilt(1),
since
.I ra_rgbe
only allows integer f-stop changes.
In this mode,
.I ra_rgbe
should be used with the
.I \-r
option.
.SH NOTES
Hyperspectral Radiance pictures (.hsr files) are
converted to approximate RGBE pixels.
However, the colors may not be very accurate.
Pass the HSR picture through
.I rcomb(1)
or
.I ra_xyze(1)
first if greater color fidelity is required.
.SH AUTHOR
Greg Ward
.SH ACKNOWLEDGEMENT
Work on this program was initiated and sponsored by the LESO
group at EPFL in Switzerland.
.SH "SEE ALSO"
pfilt(1), printf(1), ra_xyze(1), rcomb(1), rpict(1)
Revision:	1.4
Committed:	Tue Oct 1 01:16:26 2024 UTC (13 months ago) by greg
Branch:	MAIN
Changes since 1.3:	+3 -1 lines
Log Message:	feat(ra_xyze): added accurate conversion of hyperspectral pictures on input
#	User	Rev	Content
1	greg	1.4	.\" RCSid "$Id: ra_rgbe.1,v 1.3 2024/09/10 20:24:42 greg Exp $"
2	greg	1.1	.TH RA_RGBE 1 1/23/98 RADIANCE
3			.SH NAME
4			ra_rgbe - convert between different RADIANCE picture types
5			.SH SYNOPSIS
6			.B ra_rgbe
7			[
8			.B \-r
9			][
10			.B "\-e +/-stops"
11			][
12			.B \-f
13			][
14			.B "\-n frameno"
15			]
16			[
17			.B input
18			[
19			.B outspec
20			]
21			]
22			.SH DESCRIPTION
23			.I Ra_rgbe
24			converts between RADIANCE run-length encoded and flat formats, and
25			separates concatanated animation frames produced by
26			.I rpict(1).
27			The
28			.I \-e
29			option specifies an exposure compensation in f-stops (powers of two).
30			Only integer stops are allowed, for efficiency.
31			By default,
32			.I ra_rgbe
33			produces a flat RADIANCE picture file from any type of RADIANCE
34			input picture.
35			The
36			.I \-r
37			option causes
38			.I ra_rgbe
39			to produce a run-length encoded file instead.
40			.PP
41			If the input file consists of multiple animation frames as produced by
42			.I rpict
43			with the
44			.I \-S
45			option,
46			.I ra_rgbe
47			will read each frame and write it to the output file created by calling
48			.I printf(3)
49			with the output specification and frame number as arguments.
50			If the output specification begins with an exclamation mark ('!'),
51			then this interpreted as a command spec., which is also run through
52			.I printf
53			with the frame number to get the final command.
54			This command must accept a Radiance picture on its standard input,
55			and may write results either to a file or to the standard output.
56			The
57			.I \-n
58			option may be used to select a specific frame for output, and
59			other frames in the input will be skipped.
60			Normally, all frames will be read and written.
61			.PP
62			.I Ra_rgbe
63			will report an error and exit if the target output file already exists,
64			unless the
65			.I \-f
66			option is given.
67			If the output file is missing, the standard output is used.
68			If the input file is missing or set to '-', the standard input is used.
69			.SH NOTES
70			The file format for RADIANCE pictures was changed between release
71			1.4 and release 2.0.
72			The older format can still be read by all the programs, but only
73			the newer format is produced.
74			This newer format cannot be read by RADIANCE software prior to
75			release 2.0.
76			.PP
77			.I Ra_rgbe
78			provides some downward compatibility by producing files that can
79			be read by older RADIANCE software.
80			The resultant files are also easier to manipulate with programs
81			designed to read raw raster data.
82			.PP
83			The other use for
84			.I ra_rgbe
85			is as a quicker way to adjust the exposure of a RADIANCE picture than
86			.I pfilt(1),
87			since
88			.I ra_rgbe
89			only allows integer f-stop changes.
90			In this mode,
91			.I ra_rgbe
92			should be used with the
93			.I \-r
94			option.
95	greg	1.3	.SH NOTES
96			Hyperspectral Radiance pictures (.hsr files) are
97			converted to approximate RGBE pixels.
98			However, the colors may not be very accurate.
99			Pass the HSR picture through
100			.I rcomb(1)
101	greg	1.4	or
102			.I ra_xyze(1)
103	greg	1.3	first if greater color fidelity is required.
104	greg	1.1	.SH AUTHOR
105			Greg Ward
106			.SH ACKNOWLEDGEMENT
107			Work on this program was initiated and sponsored by the LESO
108			group at EPFL in Switzerland.
109			.SH "SEE ALSO"
110	greg	1.3	pfilt(1), printf(1), ra_xyze(1), rcomb(1), rpict(1)