Laser Profilometry Object Identification

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Solution Overview

Problem

Current profilometric identification methods for 3D objects, such as aircraft, using radar signatures are not sufficiently precise due to intense but few peaks, making it difficult to discriminate between objects with similar profiles.

Innovation Solution

A method involving the acquisition of profilometric signatures using a pulsed laser beam with a length at least 10 times shorter than the object, incorporating coherent and incoherent components, and processing through Shepp-Logan filtering and centered moments to enhance discrimination, along with database creation through digital simulation and facetization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radar profilometry is used to identify 3D objects, then identification can be performed, but the signature contains very intense but few peaks which are not sufficiently precise to discriminate between objects with similar profiles

Engineering Contradiction:
Improveidentification precisionVSAvoidsignature detail
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the electromagnetic wave interaction by separating coherent reflection components from incoherent diffusion components in the profilometric signature. This segmentation allows both components to be processed and combined, preserving detailed information that would be lost in traditional radar profilometry which only captures intense peaks.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If a pulsed laser beam with very short length is used, then more precise profilometric signature can be obtained, but the device complexity increases

Engineering Contradiction:
Improveprofilometric signature precisionVSAvoidlaser system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical radar systems with an optical laser-based profilometry system. By using optical waves instead of radio waves, the system achieves higher precision measurements while the complexity is managed through digital signal processing of coherent and incoherent components rather than complex hardware modifications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If traditional radar signatures with few intense peaks are used, then acquisition is simple, but discrimination between similar objects is difficult

Engineering Contradiction:
Improvesignature acquisition simplicityVSAvoidobject discrimination capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent adds a new dimension to the profilometric signature by incorporating both coherent reflection components and incoherent diffusion components. This dimensional expansion of the signature space provides richer information for object discrimination while maintaining the simplicity of laser-based acquisition, transforming a one-dimensional intensity measurement into a multi-component signature.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 more accurate and stable signatures, enabling better discrimination between objects by increasing the signal-to-noise ratio and reducing confusion between similar profiles.

Implementation Method 1

pointing at the object a pulsed laser beam of length Li

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

the signature comes from the back-scattering of the electromagnetic wave by the object

Methodology Applied
Scientific EffectBack-scattering: Scattering

Implementation Method 3

a coherent component representative of the reflection of the laser beam on the object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

an incoherent component representative of the diffusion of the laser beam on the object

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP1991945B1Method for identifying by laser profilometry
Publication Date: 2009.06.03 THALES SA
  • EP1991945B1 patent drawingFigure 1a~1b
  • EP1991945B1 patent drawingFigure 2
  • EP1991945B1 patent drawingFigure 3~4

AI summary

The invention concerns a method for identifying an object by profilometry including a step of acquiring a profilometric signature of the object and a step of comparing a signature of the object representing the acquired signature with signatures of a database. The profilometric signature of the object is obtained by pointing on the object a pulsed laser beam of length L1, said length L1 being at least 10 times shorter than the length R1, of the object considered along the pointing axis of the laser.