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ra_t8(1) [xfree86 man page]

RA_T8(1)						      General Commands Manual							  RA_T8(1)

NAME
ra_t8 - convert RADIANCE picture to/from Targa 8-bit image file SYNOPSIS
ra_t8 [ -d ][ -b ][ -c ncolors ][ -g gamma ][ -e +/-stops ][ -n sampfac ] input [ output ] ra_t8 -r [ -g gamma ][ -e +/-stops ] [ input [ output ] ] DESCRIPTION
Ra_t8 converts between RADIANCE and Targa 8-bit color-mapped image files (type 1 in Targa's documentation). In the default mode, a RADI- ANCE picture is converted to a color-mapped Targa file of the same horizontal and vertical dimensions with 8-bits per pixel. The -d option turns off dithering. The -b option converts the image to black and white. Only with this option can the input be taken from stdin. The -c option allows fewer than 256 colors. The -g option specifies the exponent used in gamma correction; the default value is 2.2. An expo- nent of 1.0 turns gamma correction off. The -e option specifies an exposure compensation in f-stops (powers of two). Only integer stops are allowed, for efficiency. The -n option specifies a sampling factor for neural network color quantization. This value should be between 1 and 80, where 1 takes the longest and produces the best results in small areas of the image. If no value is given, a faster median cut algorithm is used. The -r option invokes a reverse conversion, from an 8-bit Targa file to a RADIANCE picture. If the output file is missing, the standard output is used. AUTHORS
Greg Ward Anthony Dekker provided the code for neural network color quantization BUGS
Run-length encoded files can be read but not written with this program. SEE ALSO
pfilt(1), ra_bmp(1), ra_bn(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t16(1), ra_tiff(1), ximage(1) RADIANCE
5/30/95 RA_T8(1)

Check Out this Related Man Page

RA_BMP(1)						      General Commands Manual							 RA_BMP(1)

NAME
ra_bmp - convert RADIANCE picture to/from Windows BMP image SYNOPSIS
ra_bmp [ -b ][ -g gamma ][ -e spec ][ -p xr yr xg yg xb yb xw yw ] [ [ input|- [ output ] ] ra_bmp -r [ -g gamma ][ -e +/-stops ] [ [ input|- [ output ] ] DESCRIPTION
Ra_bmp converts between RADIANCE and a Windows BMP image. During forward conversion, the -b option produces 8-bit grayscale output rather than 24-bit RGB. The -g option specifies the exponent used in monitor gamma correction; the default value is 2.2. The -e option specifies a tone-mapping method or exposure compensation. If the argument is one of the special words "auto", "human", or "linear", the image will be tone-mapped with histogram adjustment, human vision simulation, or an averaged linear exposure, respectively. (These words may be abbreviated by one or more letters.) Otherwise, the exposure specification is interpreted as a linear compensation value in integer f- stops, which must be proceeded by a '+' or '-'. The CRT color output primaries may be specified with the -p option. The -r option invokes a reverse conversion, from a Windows BMP image to a RADIANCE picture. Tone-mapping and monitor primaries are not supported for reverse conversion. Ra_bmp can accept 16-bit or color-mapped BMP files on input, but cannot not produce them on output. A hyphen ('-') may be specified to indicate standard input for either forward or reverse conversion so that an output file may be speci- fied. If the BMP input is taken from the standard input or sent to the standard output without tone-mapping, then the scanlines may be reversed from their usual ordering. Reversed scanlines sometimes causes difficulties for programs attempting to interpret the resulting RADIANCE picture or BMP image, which may be rejected or displayed inverted. AUTHOR
Greg Ward SEE ALSO
pfilt(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t8(1), ra_t16(1), ra_tiff(1), ximage(1) RADIANCE
3/25/04 RA_BMP(1)
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