.TH LUM 9.1
.SH NAME
lum \- compute luminance
.SH SYNOPSIS
.B fb/lum
[
.I input
]
.SH DESCRIPTION
.I Lum
computes the luminance of the input picture using the NTSC formula
.IR L =.299 R +.587 G +.114\f2B\f1.
Pixel values are mapped through the input image's color map, if any.
The resulting image is written to standard output.
.SH SOURCE
.B /sys/src/fb/lum.c
.SH "SEE ALSO
.IR picfile (9.6)