Specific lighting spectrum matching by normalized correlation coefficient and generalized reduced gradient method

The optimization matching procedure for specific LED spectrum matching is proposed by the normalized correlation coefficient and generalized reduced gradient method in this study. The different spectrum means different color temperature, color rendering index, and lighting quality features. However, the specific spectrum for human centric lighting or light therapy may not be achieved by single light source but by multi-lighting sources for cost consideration. Therefore, the Gaussian distributions are used to define the specific spectrum and generate the row data rapidly for the matching calculation. The normalized correlation coefficient is used to evaluate the spectrum matching result and optimized by generalized reduced gradient method. Finally, the specific spectrum is matched with multi-lighting sources in the optimized mixing ratio from the lighting sources database.