Helmet-Mounted Optical Position Detection Using Coplanar Sensors

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Solution Overview

Problem

Existing systems for optical position and orientation detection of objects in the aeronautical field face challenges such as ambiguity in position and attitude determination, sensitivity to system dynamics, and the need for high precision, particularly in environments with complex cockpit topologies and electromagnetic disturbances.

Innovation Solution

The system employs electro-optical sensors with linear CCD sensors positioned in the same plane on a pilot's helmet, using a holographic video projector to project test patterns that allow for the calculation of vanishing points and determination of posture through the intersection of beam networks, eliminating the need for precise sensor positioning and reducing computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple cameras and sensors are used for electro-optical posture detection, then measurement precision is improved, but device complexity increases and real-time analysis becomes computationally intensive

Engineering Contradiction:

Improveposture detection precisionVSAvoidnumber of cameras and sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the detection task by using a single camera to capture images of multiple independently positioned sensors on the helmet. Each sensor's position is determined separately through image processing, dividing the complex multi-sensor problem into simpler individual sensor detection tasks that can be processed more efficiently

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses visual copying by projecting a known pattern onto the sensors and capturing their positions through camera images. The 3D position information is obtained by creating a visual copy of the sensor arrangement in the image plane and processing these 2D image coordinates to reconstruct 3D spatial positions

Inventive Principle:

Principle #26Copying

2Reliability

If electromagnetic posture detection is used, then robustness to optical disturbances is improved, but susceptibility to electromagnetic disturbances worsens

Engineering Contradiction:

Improverobustness to optical disturbancesVSAvoidelectromagnetic disturbances

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electromagnetic detection mechanisms with an optical-mechanical system. Instead of using electromagnetic fields for detection, the system uses a camera-based optical system to detect the positions of sensors on the helmet, thereby avoiding susceptibility to electromagnetic disturbances while maintaining robustness through optical detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If linear sensors are positioned in a parallelogram configuration, then orientation determination is improved, but mechanical positioning precision requirements worsen

Engineering Contradiction:

Improveorientation determination accuracyVSAvoidsensor positioning tolerance

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the sensor configuration adaptable rather than fixed. The system can process arbitrary sensor positions and orientations through image analysis, allowing the sensor arrangement to be dynamically adjusted during installation without requiring precise pre-positioning, as the software can compensate for various configurations

Inventive Principle:

Principle #15Dynamics

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 enhances precision and robustness by simplifying sensor placement, reducing mechanical precision requirements, and improving resistance to environmental disturbances, while maintaining accurate position and orientation tracking.

Implementation Method 1

The mobile part with respect to the fixed reference which constitutes the fixed part is equipped with: a first electro-optical device fixed to the mobile part; a second electro-optical device coplanar with the first electro-optical device and not parallel

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2169421B1System for optical detection of the position and/or orientation of objects comprising at least two coplanar sensors

Publication Date: 2015.02.25 THALES SA

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AI summary

The electro-optical system for determining the position and orientation of a moving part comprises a fixed projector having a projection center (O) and a moving part. The projector is rigidly connected to a virtual image plane, and the moving part is rigidly connected to two linear sensors defining a first and a second direction vector. The fixed part projects patterns, not shown, onto the image plane and the sensors, forming at least two intersecting gratings of at least three parallel segments each.The two electro-optical devices are coplanar and their directions intersect, the orientation and position of the moving part are determined by calculating the positions of the projections on the image plane of a first triplet of points comprising the projections of three points, these three points are known by measurement of the first electro-optical device and of a second triplet of points comprising the projections of three points, these three points are known by measurement of the second electro-optical device.