Transparent Object Visibility Measurement Under Ice Accretion
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Solution Overview
Problem
Current methods lack a standardized protocol to quantify the loss of visibility through transparent objects due to icing, which is crucial for evaluating and comparing different anti- or de-icing systems, particularly for helicopter windshields, as existing protocols do not accurately reflect the dynamic and heterogeneous nature of ice accretion and its impact on visibility.
Innovation Solution
A method involving a light source, high contrast providing object, and image acquisition device is used to emit a light beam through a transparent object under icing conditions, acquiring images over time, and analyzing blur to quantify the loss of visibility by determining haze levels, which can be correlated with a transparency index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If light transmittance measurement is used to detect ice accretion, then detection capability is improved, but it cannot accurately characterize empirical loss of visibility experienced by pilots
Solution Approach 1:
The patent replaces traditional optical measurement systems (light transmittance meters) with a human-subject-based visual acuity testing system. Instead of using mechanical/optical devices to measure transparency, the system uses human pilots or test subjects to perform letter recognition tasks, directly measuring the empirical visibility loss they experience. This substitution captures the subjective human perception of visibility rather than objective optical properties.
Solution Approach 2:
The patent introduces a high-contrast letter pattern chart as an intermediary object between the ice-covered windshield and the measurement system. The letters serve as a standardized test target that translates the complex optical effects of ice accretion into a quantifiable metric (letter recognition capability). This intermediary enables the conversion of subjective visual experience into objective measurement data.
2Ease of manufacture
If predetermined anti-icing performance objectives based on light transmittance are used, then implementation is simplified, but they are not suitable for comparing different anti- or de-icing technologies
Solution Approach 1:
The patent creates a universal measurement protocol that can evaluate multiple types of anti-icing technologies (heating devices, vibrating devices, hydrophobic coatings, ice-repellent treatments) using a single standardized method. The visual acuity-based measurement approach is technology-agnostic and can assess any system that maintains windshield transparency, enabling fair comparison across different technological approaches that were previously incompatible with traditional light transmittance standards.
3Device complexity
If traditional transparency measurement protocols are used, then measurement process is simplified, but they cannot reflect heterogeneous loss of visibility generated by ice
Solution Approach 1:
The patent applies local quality by using a high-contrast letter pattern chart with varying spatial frequencies and orientations. Different regions of the chart contain letters of different sizes and orientations, allowing the measurement to capture localized variations in visibility loss across different areas of the windshield. This enables detection of heterogeneous ice patterns that uniform transparency measurements would average out and miss.
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
Enables the characterization of visibility loss due to ice accretion, allowing for the evaluation and comparison of anti- or de-icing technologies and setting performance objectives, adaptable to various transparent objects, and potentially enabling automatic de-icing systems.
Implementation Method 1
emitting a light beam from the light source through the high contrast providing object toward the transparent object, the light beam being directed through the transparent object and the surface of the transparent object toward the image acquisition device
Data Source
AI summary
A method, comprising: providing a light source, a high contrast providing object, and an image acquisition device; emitting a light beam from the light source through the high contrast providing object, a transparent object and a surface of the transparent object toward the image acquisition device; exposing the surface of the transparent object to icing conditions such that a layer of ice is formed by ice accretion on the surface, wherein the light beam traverses the layer of ice after having traversed the transparent object; acquiring a series of images over time of the high contrast providing object using the image acquisition device; determining blur occurring in the series of images over the time; and quantifying the loss of visibility over the time through the transparent object on the basis of the determined blur.