Ice Thickness Measurement Using Light Diffusion Intensity Profiles

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Solution Overview

Problem

Existing methods for estimating ice thickness on aircraft surfaces are unreliable when the air/ice interface is not plane, as deformations lead to unpredictable refraction of light rays, making it difficult to measure ice thickness accurately across varying aircraft surface shapes.

Innovation Solution

A system comprising a light source that projects a collimated beam to generate a luminous pattern by diffusion in the ice, an imaging device to capture the pattern, and a calculation unit that estimates ice thickness based on the luminous intensity profile, using predetermined tables to account for direct diffusion rather than refraction, allowing for measurements regardless of the air/ice interface shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If refraction-based measurement method is used, then measurement precision is improved when ice surface is plane, but reliability deteriorates when air/ice interface is deformed

Engineering Contradiction:

Improveice thickness measurement precisionVSAvoidmeasurement reliability on deformed surfaces

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from refraction angle to light diffusion intensity profile. By measuring the intensity distribution of light that has diffused through the ice rather than relying on refraction angle, the system can accurately measure ice thickness regardless of surface deformation. The diffusion pattern's characteristics (intensity, spread) provide information about ice thickness without being affected by interface shape.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the optical refraction mechanism with light diffusion mechanism. Instead of using a camera to capture refraction spots and calculate thickness from refraction angles, the system uses a light source to create diffusion patterns in the ice and measures the intensity profile of this diffusion. This substitution eliminates the dependency on plane surface geometry while maintaining measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If refraction angle measurement is used, then ice thickness can be determined, but the method fails when air/ice surface is not plane

Engineering Contradiction:

Improveice thickness measurement capabilityVSAvoidadaptability to various surface shapes

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The measurement parameter is changed from geometric refraction angle to optical diffusion intensity profile. The diffusion intensity pattern provides information about ice thickness through the relationship between light propagation distance and intensity attenuation, a parameter that remains valid regardless of surface geometry. This allows the system to adapt to various surface shapes including curved, uneven, and deformed ice surfaces.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The light diffusion-based measurement method provides universal applicability across different surface geometries. The same measurement system and algorithm can measure ice thickness on plane surfaces, curved surfaces, and deformed surfaces without requiring adjustment or recalibration, making the system universally applicable to various aircraft surface configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 accurate measurement of ice thickness, including submillimeter thicknesses, on aircraft surfaces with any shape, using a low-cost collimated light source and high dynamic range imaging, eliminating the need for a plane air/ice interface, and improving measurement accuracy by accounting for diffusion patterns.

Implementation Method 1

a light source configured to project a collimated beam onto the surface in such a manner as to generate a luminous pattern by diffusion in the ice

Methodology Applied

Scientific EffectLight diffusion: Diffusion

Implementation Method 2

an imaging device configured to acquire an image of the ice including the luminous pattern

Methodology Applied

Scientific EffectImage acquisition: Photography

Data Source

PatentUS9568305B2Method and system for measuring the thickness of ice on a surface, notably of an aircraft, using a luminous pattern generated by diffusion in the ice

Publication Date: 2017.02.14 AIRBUS OPERATIONS (SAS)

AI summary

A system and method for providing an estimate of the thickness of the ice regardless of the shape of its surface at the level of the air/ice interface. To this end the system and method measure an intensity profile of a luminous pattern generated by diffusion in the ice, which enables the system to measure the thickness of the ice even when the air/ice surface is not plane.