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© National Instruments Corporation A-1 NI PCI-1405 User Manual
A
Introduction to Color
Color is the wavelength of the light we receive in our eye when we look at
an object. In theory, the color spectrum is infinite. Humans, however, can
see only a small portion of this spectrum—the portion that goes from the
red edge of infrared light, which is the longest wavelength, to the blue edge
of ultraviolet light, which is the shortest wavelength. This continuous
spectrum is called the visible spectrum, as shown in Figure A-1.
Figure A-1. White Light and the Visible Spectrum
White light is a combination of all colors at once. The spectrum of white
light is continuous and goes from ultraviolet to infrared in a smooth
transition. You can represent a good approximation of white light by
selecting a few reference colors and weighting them appropriately.
The most common way to represent white light is to use three reference
components, such as red, green, and blue (R, G, and B primaries). You
can simulate most colors of the visible spectrum using these primaries.
For example, video projectors use red, green, and blue light generators,
and an RGB camera uses red, green, and blue sensors.