Imaging Sensor Positioning Using Visual Markers in GPS-Denied Spaces

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional position and orientation determination methods, such as GPS, are unreliable in environments with electromagnetic interference, radio frequency multipath issues, and satellite signal drop-outs, and may not provide sufficient accuracy for certain applications, especially in enclosed spaces or underwater.

Innovation Solution

A method and system using an imaging sensor to capture two-dimensional images of markers with known coordinates, determining unit direction vectors and apex angles, and iteratively calculating marker distances and device position and orientation through processing circuitry, allowing for six degrees of freedom determination in three-dimensional space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If GPS technology is used for position determination, then convenience and ease of operation are improved, but reliability deteriorates in environments with electromagnetic interference, radio frequency multipath issues, and satellite signal drop-outs

Engineering Contradiction:

Improveconvenience of position determinationVSAvoidreliability of position determination

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary positioning system using imaging sensors and visual markers as a mediator between the mobile device and the environment. Instead of directly relying on satellite signals, the system captures images of markers and computes position through image processing and geometric calculations, thereby resolving the contradiction by providing an alternative pathway that works in GPS-denied environments

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the radio frequency-based GPS system with an optical-based imaging system. By substituting electromagnetic wave reception (GPS) with light capture (imaging sensor) and computational geometry (apex angle calculations), the system achieves reliable positioning in environments where RF signals fail, thus improving reliability while maintaining ease of operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If conventional position measurement devices are used, then ease of operation is improved, but measurement precision deteriorates in applications requiring high accuracy

Engineering Contradiction:

Improveease of position measurementVSAvoidprecision of position determination

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces conventional position measurement devices with an imaging-based system that uses apex angle calculations and iterative optimization algorithms. This substitution enables high-precision position determination by leveraging the geometric relationships between markers and the mobile device, achieving measurement precision suitable for applications like precision flight and surgical guidance while maintaining ease of operation through automated image capture and processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If imaging sensor-based position determination is implemented, then reliability and measurement precision are improved, but device complexity increases due to iterative processes and multiple calculations

Engineering Contradiction:

Improvereliability of position determinationVSAvoidcomplexity of processing circuitry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining marker coordinates in a known coordinate system and pre-calibrating the imaging sensor's intrinsic parameters (focal length, principal point). This preliminary setup eliminates the need for complex real-time calibration and reduces the computational burden during actual position determination, thereby improving reliability while managing device complexity through advance preparation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent transitions from two-dimensional image coordinates to three-dimensional position determination by introducing the apex angle concept and using iterative optimization in 3D space. This dimensional transformation allows the system to compute reliable 3D positions from 2D images by leveraging the geometric constraints of the marker configuration and the imaging geometry, achieving high reliability while the computational complexity is managed through efficient iterative algorithms

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11372455B2Imaging sensor-based position detection

Publication Date: 2022.06.28 JOHNS HOPKINS UNIVERSITY

AI summary

An example method for determining a mobile device position and orientation is provided. The method may include capturing a two-dimensional image of a surface including at least four markers, and determining a unit direction vector for each of the at least four markers based on an association between a pixel location of each of the at least four markers in the two-dimensional image. The method may further include determining apex angles between each pair of the unit direction vectors, and determining marker distances from the imaging sensor to each of the at least four markers via a first iterative process based on the apex angles. Additionally, the method may include determining the mobile device position with respect to the coordinate frame via a second iterative process based on the marker distances, the apex angles, and the coordinates of each of the at least four markers.