Patent ID: 8624527

Claim:
An illumination system comprising: a plurality of LED units, each LED unit comprising a plurality of differently colored, independently controllable LEDs forming a color gamut; a system controller for generating control signals for each of the LED units consistent with a desired system-level output; at least one sensing unit for sensing an operating state of the LEDs during operation thereof; a plurality of local controllers each associated with at least one LED unit, each local controller comprising a memory and a compensator, wherein: the memory comprises calibration data for use over a short time period, the compensator updates the calibration data based on measurements from a sensing unit over a long time period longer than the short time period, based at least in part on the calibration data, the local controller operates the LEDs of the LED unit to maintain output intensities consistent with commands issued by the system controller, and the calibration data comprises in-cycle calibration data and long-term calibration data, the in-cycle calibration data being used by the local controller over a single cycle between activation and de-activation of the LED unit, and the long-term calibration data being used by the local controller to adjust a baseline current level to each of the LEDs.