Tunable Lighting System Color Gamut Approximation
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Solution Overview
Problem
Current variable color lighting systems can only span a part of the color triangle, leading to uncertainty in color output and limited color rendering index, as they may not be able to produce colors outside their gamut, and approximating within the gamut can result in significant differences in perceived color temperature and CRI.
Innovation Solution
A method and system that receive a target color point and flux, compare it to the lighting system's gamut, and if outside, determine a first approximation color point within the gamut based on minimizing distance in the x-y color plane, then adjust the duty cycles of light sources to achieve the highest possible flux, and if necessary, find a second approximation point to meet the target flux, ensuring a closer match to the requested color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lighting system attempts to produce colors outside its gamut, then the color rendering index and perceived color accuracy deteriorate, but the system cannot expand its physical gamut beyond what the light sources define
Solution Approach 1:
The system pre-calculates and stores mapping data for approximating out-of-gamut colors to the nearest in-gamut colors. This preliminary preparation allows the system to quickly determine the best approximation without real-time complex calculations, maintaining color accuracy while adapting to gamut limitations.
Solution Approach 2:
The system changes the duty cycles of individual light sources dynamically to achieve the desired color output. By adjusting these parameters within the constraints of the available gamut, the system optimizes color rendering for both in-gamut and out-of-gamut requests.
2Reliability
If the system limits the allowable gamut to the minimal guaranteed gamut, then color rendering reliability improves, but the adaptability and user choice significantly deteriorate
Solution Approach 1:
The system pre-calculates approximation mappings for the entire possible gamut range, not just the minimal guaranteed gamut. This allows it to reliably handle any color request by providing the best possible approximation, maintaining consistency while maximizing the available color range.
Solution Approach 2:
The system is designed to handle both in-gamut and out-of-gamut color requests through a unified approach. The same control mechanism and approximation algorithms work for all color requests, making the system universally applicable across the full spectrum of possible color inputs.
3Device complexity
If the system merely approximates the nearest color point within the gamut, then the device complexity remains low, but the color rendering index and perceived color temperature accuracy significantly deteriorate
Solution Approach 1:
The system pre-calculates and stores optimal approximation mappings that consider multiple factors including color temperature, CRI, and perceptual accuracy. This preliminary computation creates a comprehensive lookup table that guides real-time color approximation, significantly improving accuracy without adding complexity to the real-time control algorithm.
Solution Approach 2:
The system uses pre-computed approximation data that captures the optimal mapping between requested colors and achievable colors. This copied information from offline calculations allows the real-time system to achieve high accuracy without performing complex optimization routines during operation.
4Illumination intensity
If the system adjusts duty cycles to achieve highest possible flux at the approximation color point, then the brightness output improves, but the ability to meet exact target flux requirements deteriorates
Solution Approach 1:
The system pre-calculates the relationship between duty cycle settings and resulting flux output for each approximated color point. This preliminary data allows the system to determine the optimal duty cycle that achieves the target flux as closely as possible, balancing maximum brightness with flux accuracy for out-of-gamut colors.
Data Source
AI summary
A method for providing a light output from a lighting system (100) capable of emitting light within a lighting system color gamut (202) in an x-y color plane, comprising the steps of: receiving (302) a light output target comprising a target color point (210, 219) and a target flux; comparing (304) the target color point with the lighting system color gamut (202); and if the target color point is outside of the color gamut: determining (310) a first approximation color point (212, 220) inside the color gamut based on a minimization of a distance in the x-y color plane between the target color point and the first approximation color point; determining (312) a highest possible flux achievable by the lighting system at the first approximation color point; if the highest possible flux achievable by the lighting system at the first approximation color point is equal to or larger than the target flux, control (309) the lighting system to provide light defined by the first approximation color point and the target flux; and if the highest possible flux achievable by the lighting system at the first approximation color point is lower than the target flux, determining (314) a second approximation color point (214, 222) at which the lighting system is capable of providing the target flux based on a minimization of a distance in the x-y color plane between the first approximation color point and the second approximation color point; and controlling (315) the lighting system to provide light defined by the second approximation color point and the target flux.