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Unformatted text preview: Light and Wavelengths CS 450: Introduction to Digital Signal and Image Processing • Visible light is in the range 400 nm (blue) to 700 nm (red). Color Processing Perception of Light Cones and Wavelengths • Cones have three different kinds of color-sensitive pigments, each responding to a different range of wavelengths. • These are roughly “red”, “green”, and “blue” in their peak response but each responds to a wide range of wavelengths. • The combination of the responses of these different receptors gives us our color perception. • This is called the tristimulus model of color vision. (From G&W, individual cone responses normalized) Cones and Wavelengths • The sensitivity and number of the three types of cones are different • More sensitive overall to green and red than to blue Relative responses of the three different cones Luminous Efficiency Function • The luminous efficiency function combines the responses of all three to measure perceived brightness for different wavelengths RGB Color Model RGB Color Channels • Simplest model is just to store red, green, and blue values • Colors can be thought of as points in a RGB cube “Web Safe” Colors Primaries and Secondaries • Primary colors: ones mixed to make other colors • Secondary colors: pairwise combinations of primaries • Can be additive or subtractive CMY Model • Subtractive media absorb rather than emit light – Real-world objects – Paint – Printing ink • Th...
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This document was uploaded on 03/15/2012.

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