Minimal-Energy Control Sequences for Linear Multi-Primary Displays

A control sequence gives the intensities of the primaries for a pixel in a display. A multi-primary display has four or more primaries, so that multiple control sequences can sometimes produce the same colour. Different primaries likely consume different amounts of energy; furthermore, the energy consumption can be a complicated function. A minimal-energy control sequence for a target colour produces that colour with as little energy as possible. This paper shows that such minimal-energy sequences take a simple geometric form when each primary’s energy function is linear. The display gamut, in CIE XYZ space, can be dissected into parallelepipeds. The originating vertex of each parallelepiped is the sum of a set of primaries at full intensity. Each edge of a parallelepiped is the translation of one primary. A colour with XYZ coordinates in a certain parallelepiped is a unique linear combination of the primaries in the originating vertex, and the three edge primaries. This paper proves that there exists a dissection such that these linear combinations are minimal-energy control sequences. In the generic case, this dissection is unique. An algorithm for a minimal-energy dissection is presented, along with an example.