Camera-Based Ambient Light Estimation Using Band-Stop Filter
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Solution Overview
Problem
Current sensor-driven lighting systems fail to accurately separate and characterize the contributions of ambient light, particularly distinguishing daylight from artificial light sources, which limits their ability to provide advanced light control.
Innovation Solution
A camera-based system with a band-stop filter is used to estimate ambient light by allowing visible and near-infrared light to pass through, enabling signal processing of pixel information from red, blue, and green color channels to differentiate daylight from artificial light contributions, allowing for more accurate light source adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photocell is used to monitor ambient light levels, then the lighting system can control light source operation, but the system cannot separate daylight contribution from artificial light source contribution
Solution Approach 1:
The patent segments the ambient light measurement into multiple wavelength channels (visible and near-infrared) to differentiate between daylight and artificial light sources. By dividing the spectral range into distinct measurement bands, the system can analyze the spectral characteristics of ambient light and determine the contribution of each light source type separately.
Solution Approach 2:
The patent extends the measurement dimension from simple intensity detection (single photocell) to spectral dimension analysis (multi-wavelength camera). By adding the spectral dimension through wavelength-selective filtering and multi-channel detection, the system gains the ability to identify and separate different light source contributions based on their spectral signatures.
2Measurement precision
If a camera with band-stop filter is used to separate daylight and artificial light contributions, then light control accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the camera system multi-functional by using it for both visible light capture and near-infrared spectral analysis. The same camera hardware, when combined with appropriate filtering and processing, performs multiple measurement functions that would otherwise require separate dedicated sensors, thereby reducing overall system complexity despite the advanced capabilities.
Solution Approach 2:
The band-stop filter acts as an intermediary element that enables spectral separation without requiring complex multi-sensor arrangements. The filter mediates between the broadband camera sensor and the spectral analysis requirement, allowing the system to achieve precise daylight/artificial light separation through relatively simple optical modification.
3Adaptability or versatility
If multiple wavelength channels are used to characterize ambient light contributors, then light control capability is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent achieves enhanced light control adaptability by changing the spectral parameter measurement rather than requiring multiple complete sensor systems. By varying the wavelength selection through filtering and analyzing different spectral parameters, the system gains versatility in characterizing ambient light sources while maintaining a unified hardware platform that is easier to manufacture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides advanced light control by enabling precise estimation of daylight contribution, allowing lighting units to adjust their light emission parameters, such as intensity, to optimize lighting based on accurate ambient light analysis.
Implementation Method 1
A camera with a band-stop filter that allows visible and near infra-red light to pass through
Implementation Method 2
pixel information of red, blue, and/or green color channels
Data Source
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AI summary
A lighting unit (10) for estimating an amount of daylight in a lighting environment includes: a light source (12); a filter (330) configured to block incident light in a first wavelength range, the incident light comprising both daylight and non-daylight incident light; a camera (32) configured to receive the filtered incident light and generate a detection signal (342), the filtered incident light being outside the first wavelength range; and a controller (22) in communication with the camera and configured to process the detection signal to estimate the amount of daylight incident light.