Function File: lab = xyz2lab (xyz)
Function File: lab_map = xyz2lab (xyz_map)

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

A color in the CIE XYZ color space consists of three values X, Y and Z. Those values are designed to be colorimetric, meaning that their values do not depend on the display device hardware.

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 also a colorimetric colorspace. It is designed to incorporate the human perception of color differences.

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

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

See also: lab2xyz, rgb2lab, rgb2hsv, rgb2ind, rgb2ntsc.

Package: image