How to convert lab color space to rgb color image?

To correct non uniform illumination in a retinal image, i have converted the rgb color image to CIE lab color space, then the luminance (l) is processed separately and combined it with the chrominence (a,b). Now i want to convert it back to rgb color space.

Answer 1

[Image Analyst]

Use makecform and the lab2rgb option.

Or you can use rgb2hsv and hsv2rgb, like I do most times. LAB doesn't always have the same color for different L values, just run the attached demo to see an illustration.

[DGM]

Or you could say that color points are not constrained when working in LAB, so points can be moved out of gamut. Where they go after that is a matter of the rendering intent used by the conversion tools.

All out-of-gamut colors mapped to black:

HSV and HSL are constrained. Any color point in the cylinder described by the extents of H,S and L/V lies within RGB. Most other color models (including HSI) are not constrained, so operations within them may move colors out-of-gamut and cause unexpected color shifts when converting to RGB.