LED-based metameric light sources: Rendering the colours of objects and other colour quality criteria

Solid-state white light sources based on multiple light emitting diodes (LEDs) have three features that make them radically different from other sources of electrically generated light. These are the narrowband spectra of the individual LEDs, the possibility of controlling the light output of the individual LEDs and the limited stability of the LED's colour. These features make it possible to achieve a set of solid-state white light sources that are metameric to a selected reference light source. A computational method to optimise the intensities of narrowband LEDs to obtain these metameric light sources is proposed. The appearance of object colours under these metameric light sources differs and can be used to satisfy users' requests according to the various aspects of colour quality required, without altering the visual appearance of the light source.