Dec 30, 2010

Lab color model is preferred for computer vision

For working with computer vision and image processing, I prefer using Lab to other popular color models like RGB and CMYK. Unlike the RGB and CMYK color models, Lab color is designed to approximate human vision. It aspires to perceptual uniformity. Perceptually uniform means that a change of the same amount in a color value should produce a change of about the same visual importance. The L compoent in Lab closely matches human perception of lightness while a and b components represent stimulation along the color opponent dimensions of red-green and blue-yellow respectively.

The Lab color space is a color-opponent space. The color opponent theory states that the human visual system interprets color information by processing signals from cones and rods in an antagonistic manner. The three types of cones have some overlap in the wavelengths of light to which they respond, so it is more efficient for the visual system to record differences between the responses of cones, rather than each type of cone's individual response. The opponent color theory suggests that there are three opponent channels: red versus green (a component in Lab), blue versus yellow (b component in Lab), and black versus white (L component in Lab). Responses to one color of an opponent channel are antagonistic to those to the other color.

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