LMS Colour Space

L, M and S are the types of cone cells in the human eye.
The Spectral Sensitivity of each cell is mapped to this color space.

It is mostly used is psychophysical research.

It also makes it easy to model some of the per-cone gain adjustments that happen in the retina. The retina adjusts the sensitivity of different cones when trying to white balance a scene and some digital imaging white balancing algorithms mimic these operations in LMS space. This method is called the von Kries transform.