Use this command to gamma correct a stream of pfs images. Gamma
correction is equivalent to raising value of R, G and B (or Y for
gray-scale images) channels to 1/gamma power. More information on
gamma correction can be found at:
This command can work on color images, in which case XYZ channels are
transformed to RGB space, then they are gamma corrected before they
are converted back to XYZ. For gray-scale images (only Y channel and
XZ missing) gamma correction is applied only to Y channel.
Data can be multiplied by an optional multiplier before gamma
Note: gamma correction will set the LUMINANCE tag to DISPLAY thus
cancelling any sRGB correction when saving to LDR files (like PPM,
TIFF). This will also cause a warning message when saving to HDR
files, because the intensities after gamma correction are not linearly
related to luminance any more.