Multi-Channel Lighting Calibration Matrix for Reflection and Batch Variation
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Solution Overview
Problem
Existing calibration methods for multi-channel lighting systems fail to account for varying reflective properties of environments and luminaire production variability, leading to significant errors in light intensity measurements across different spectral ranges.
Innovation Solution
A method for calibrating multi-channel lighting systems involves obtaining total light outputs, spectral distribution mapping, and measured light intensities to derive a calibration matrix that compensates for environmental reflections and luminaire batch deviations, converting luminous flux values into calibrated illuminance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing calibration methods are used, then the calibration process is simple, but the measurement precision deteriorates due to unaccounted environmental reflections and luminaire variability
Solution Approach 1:
The calibration process is segmented into multiple measurement steps for different spectral ranges (blue, green, red, far-red), with each step targeting specific wavelength regions. This segmentation allows systematic compensation for environmental reflections and luminaire variability across different spectral bands, improving overall measurement precision while maintaining manageable process complexity through structured measurement sequences.
Solution Approach 2:
The calibration method incorporates feedback by measuring actual light output at the area of interest and comparing it with expected values. The difference (error signal) is then used to adjust and refine the calibration constants for each spectral range. This feedback mechanism enables continuous improvement of measurement accuracy by accounting for real-time environmental conditions and luminaire performance variations.
2Adaptability or versatility
If multi-channel lighting systems are used to achieve desired spectral power distributions, then the adaptability improves, but the device complexity increases due to multiple overlapping LED chip spectra
Solution Approach 1:
The spectral power distribution control is segmented into separate calibration processes for different spectral ranges (blue 400-499nm, green 500-599nm, red 600-699nm, far-red 700-799nm). Each spectral range is calibrated independently using dedicated LED chip combinations, allowing precise control of each wavelength region while simplifying the overall system management through modular calibration segments that can be processed separately.
Solution Approach 2:
Different LED chip combinations are assigned to different spectral ranges based on their specific emission characteristics. Each local spectral region receives optimized calibration using chips with appropriate spectral properties, allowing fine-tuned control of each wavelength band. This local quality approach enables precise spectral power distribution control by matching specific chip types to specific spectral regions where they perform best.
3Measurement precision
If calibration is performed without accounting for environmental reflections, then the ease of operation improves, but the measurement precision deteriorates due to reflection index variations
Solution Approach 1:
The calibration process performs preliminary measurements of the area of interest before final calibration calculations. By measuring light output at multiple spectral ranges and comparing with expected values in advance, the system identifies and compensates for environmental reflection effects before final calibration is applied. This preliminary action allows the system to account for reflection index variations without requiring complex real-time adjustments during operation.
Solution Approach 2:
The calibration method introduces an intermediary calibration constant that mediates between the raw light measurements and the final calibrated values. This intermediary parameter absorbs the effects of environmental reflections and luminaire variability, allowing the system to maintain high measurement precision while keeping the operational process simple. The calibration constant acts as a compensating factor that translates raw measurements into accurate calibrated values without requiring complex real-time calculations.
Data Source
AI summary
A method is provided of calibrating a lighting system to enable conversion between i) light output settings for a plurality of lighting channels of the lighting system, each channel having a respective color spectrum from a first set of color spectra, and ii) a light intensity at an area of interest for each of a second set of color spectra. The method derives a calibration matrix, based on a set default light outputs from the lighting channels, a mapping to light spectra to be measured, and light intensities measured at those light spectra. This calibration procedure takes advantage of the fact that using the same measurement device conventionally used for a simple calibration, it is possible to retrieve not only the total measured PPFD, but also partial PPFD values per spectral range.