Function File: rgb = lab2rgb (lab)
Function File: rgb_map = lab2rgb (lab_map)

Transform a colormap or image from CIE L*a*b* to sRGB color space.

A color in the CIE L*a*b* (or CIE Lab) space consists of lightness L* and two color-opponent dimensions a* and b*. The whitepoint is taken as D65. The CIE L*a*b* colorspace is a colorimetric colorspace. It is additionally designed to incorporate the human perception of color differences.

A color in the RGB space consists of red, green, and blue intensities. The input RGB values are interpreted as nonlinear sRGB values with the white point D65. This means the input values are assumed to be in a colorimetric (sRGB) colorspace.

Input values of class single and double are accepted. The shape and the class of the input are conserved.

The input values of L* are normally in the inteval [0, 100] and the values of a* and b* in the interval [-127, 127].

note: This function returns slightly different values than the Matlab version. But it has a better "round trip accuracy" (<2e-5) for RGB -> Lab -> RGB.

See also: rgb2lab, rgb2xyz, rgb2hsv, rgb2ind, rgb2ntsc.

Package: image