Light Attenuation Determination in Scattering Media
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Solution Overview
Problem
Existing methods for determining visibility in scattering media, such as fog, are imprecise due to the need for complex reference values and high computational effort, especially when tracking light rays in fog conditions, which limits their practicality for real-time applications like vehicle headlights.
Innovation Solution
A method for quantitatively determining the temporal and spatial distribution of light rays in a scattering medium using radiation characteristics, described by a light intensity distribution body, which accounts for scattering and absorption, allowing for a mathematically sound and metrologically verifiable representation of light attenuation, enabling accurate visibility assessment without the need for calibration or experimental reference data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ray tracing methods are used to simulate light paths in scattering media, then the accuracy of visibility determination is improved, but the computational effort becomes prohibitively high
Solution Approach 1:
The patent extracts only the essential scattering parameters (scattering coefficient and phase function) from the complex ray tracing simulation, using these extracted parameters to characterize the scattering medium without performing full ray tracing. This extraction approach maintains measurement precision while dramatically reducing computational effort.
Solution Approach 2:
The patent changes the approach from tracking individual light rays to using statistical parameters (scattering coefficient and phase function) to describe light propagation. This parameter transformation enables visibility determination with much lower computational cost while preserving accuracy.
2Measurement precision
If reference values are determined through complex experimental calibration, then the accuracy of visibility estimation is improved, but the device complexity and calibration effort increase
Solution Approach 1:
The patent enables the measurement system to determine its own calibration parameters by measuring the backscatter signal at a known distance and calculating the scattering coefficient and phase function from these measurements. This self-calibration approach eliminates the need for complex external calibration equipment and procedures.
Solution Approach 2:
The patent replaces mechanical calibration equipment (such as glass diffusers and complex optical setups) with computational methods that calculate scattering parameters from measured backscatter signals. This substitution eliminates the need for physical calibration artifacts and simplifies the overall system.
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 significantly more accurate light attenuation measurements with reduced computational effort, allowing for precise determination of visibility and glare effects, enabling effective optimization of vehicle headlights and improved visibility assessment in foggy conditions.
Implementation Method 1
The fog is expressed by the coefficient of energy loss of a light beam per unit distance, the energy loss being due to the scattering behavior of the droplets
Implementation Method 2
the energy loss being due to the scattering behavior of the droplets
Data Source
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Figure 5
AI summary
A method for quantitatively determining a temporal and spatial distribution of light beams in a scattering medium from the emission characteristics of a light source, said method having the steps of: - determining a radiation direction (θ, φ) and a luminous intensity Ι(θ, φ) of one of the light beams and defining a radiation vector k with the direction (θ, φ) and the amount Ι(θ, φ), - determining a scatter-dependent luminous intensity distribution IImpuls(αImpuls, t) of the radiation vector k depending on the travel time of the light and a fog density in momentum space, - transforming the scatter-dependent luminous intensity distribution in momentum space IImpuls(αImpuls, t) into a scatter-dependent luminous intensity distribution in position space Iort(αOrt, t), - determining a luminous intensity Ε(θρ, φρ, rp) of an observer point P in position space from a distance-dependent luminous intensity ΙΕ(θ, φ, rp) and the scatter-dependent luminous intensity distribution in position space Iort(αOrt, t).