vcrgbhls(1)

PROGRAM
vcrgbhls - Conversion between NTSC RGB and HLS color spaces

SYNTAX

vcrgbhls

-i  input image filename

-o  output image filename

[-n]
    normalization factor

[-h]
    Convert (RGB to HLS) [True] or (HLS to RGB) [False]

[-V]
    Gives the version for vcrgbhls

[-U]
    Gives the usage for vcrgbhls

[-P]
    Prompts for command line options

[-A [file1]]
    Creates the answer file called vcrgbhls.ans or file1

[-a [file1]]
    Uses vcrgbhls.ans or file1 as the answer file

DESCRIPTION
vcrgbhls converts between NTSC RGB or generic RGB and HLS color spaces. Color images are displayed and manipulated using the NTSC receiver primary color system. This routine needs to work with an image normalized between 0 and 1.

The algorithm which transforms from RGB to HLS was taken from Foley & VanDam (Fundamentals of Interactive Computer Graphics), and the HLS to RGB was taken from Ken Fishkin (with our modifications).

The -h option specifies which conversion will be done. If -h = 1 (TRUE, default), the conversion is from RGB to HLS. If -h = 0 (FALSE), the conversion is from HLS to RGB.

The -n option specifies the normalization factor. The default value is 255.

This routine will not touch the data map; therefore, the map may be invalid after running this routine. The map may be deleted from the image or a new map may be inserted.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input image filename

-o  type: outfile
    desc: output image filename

OPTIONAL ARGUMENTS

-n  type: float
    desc: normalization factor
    default: 255
    bounds: value > 0.0

-h  type: boolean
    desc: Convert (RGB to HLS) [True] or (HLS to RGB) [False]
    default: true

EXAMPLES
vcrgbhls -i image1 -o image2 -h 1
this will convert image1 (RGB) to image2 (HLS) using normalization factor = 255. Normalization factor = 255 is used because an 8 color plane machine (256 colors) is being used.

vcrgbhls -i image1 -o image2 -h 2 -n 15
this will convert image1 (HLS) to image2 (RGB) using normalization factor = 15. Normalization factor = 15 is used because an 4 color plane machine (16 colors) is being used.

SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), lvcrgbhls(3)

RESTRICTIONS
vcrgbhls must have an input image of data storage type FLOAT and the input image color map model must be of type RGB or HLS.

COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.