National Instruments Image Acquisition Software - Manual (Page 46)

Appendix A StillColor
© National Instruments Corporation A-9 NI-IMAQ User Manual
used if you are performing averaging on your image. For example,
averaging an image 16 times requires four extra bits (16 =
) to represent
the increased dynamic range. In this case, using the 16-bit representation
may increase the dynamic range of your image.
Luminance, Intensity, Hue, or Saturation are defined using the Red, Green,
and Blue values in the following formulas:
Luminance = 0.299
×
Red + 0.587
×
Green + 0.114
×
Blue
Intensity = (Red + Green + Blue) / 3
Hue = ATN2 (Y, X)
where
Y = (Green - Blue) / and
X = (2
×
Red - Green - Blue) /
Saturation =
where
Y = (Green - Blue) / and
X = (2
×
Red - Green - Blue) /
32-Bit HSL and HSI
You can also pack the three 8-bit Hue, Saturation, and Luminance planes
(HSL) or the three Hue, Saturation, and Intensity planes (HSI) in one array
of 32-bit integers, which is equivalent to the 32-bit RGB representation.
2
4
2
6
X
2
Y
2 ×
2
6
UM.book Page 9 Monday, July 13, 1998 9:49 AM