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Electronic illumination systems are now available with multiple independently controllable LEDs of different spectral power distribution (SPD). These independent SPD can be combined in the proper proportions to replicate a target SPD. Generally at least four channels and sometimes eight or more channels are needed for a sufficiently broad tuning range with sufficiently high quality replication. As the number of independent channels rises above three, there are an infinite number of SPD that can achieve the same chromaticity. Algorithms employing a merit function are used to quickly sort to a good solution. In addition to spectrum, time is often an important quality of illumination such as with daylight and fire. A system that combines spectral tuning and time synchronization is referred to here as a light player. There are multiple optimization goals that may be of interest in determining the synthesized SPD. Examples include efficacy, color rendering, color saturation, high/low melanopic suppression, and smallest SPD error. One application of a light player is to replicate the time-varying SPD of daylight towards a healthier and more enjoyable indoor illuminated environment. Other applications include, retail appearance enhancement, medical diagnosis, horticulture, and standard illuminant synthesis such as D65. This talk will explore the general architecture of light players, the algorithms for synthesizing an SPD, summary information of daylight recordings, and a brief demonstration of a light player.
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