Visual-Inertial Sensor Fusion for Accurate Positional Awareness

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Solution Overview

Problem

Current technologies for providing fast, accurate, and reliable positional awareness to robots and wearable devices, such as VR/AR headsets, face challenges including high computational costs, energy inefficiency, and high costs due to reliance on expensive sensors like stereo RGB systems and active sensing methods, which limit their widespread adoption.

Innovation Solution

The implementation of a visual-inertial sensor system that offloads computational tasks from the main processor to a low-power sensor module, using a combination of grayscale and colored cameras with inertial measurement units (IMUs) to process image and inertial data, reducing costs and energy consumption while maintaining performance, and employing techniques like image undistortion, feature detection, and sensor fusion for accurate localization and tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If depth sensor based approaches are used for positional awareness, then measurement precision is improved, but use of energy increases and device cost increases

Engineering Contradiction:
Improvepositional awareness accuracyVSAvoidpower drain
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces active depth sensing mechanisms (which consume significant power) with a passive visual-inertial system. The visual system uses grayscale and color cameras to capture images, while the inertial system uses IMUs to measure motion. By fusing these passive sensing modalities, the system achieves depth and position information without the high energy consumption of active depth sensors.

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

Solution Approach 2:

The patent changes the sensing parameters from active depth measurement (high energy) to passive visual feature detection combined with inertial motion capture. The system processes image data to extract visual features and fuses them with inertial measurement data, fundamentally changing how positional information is obtained to reduce energy consumption while maintaining accuracy.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If visual approaches are used for positional awareness, then device cost is reduced, but measurement precision deteriorates due to slow processing and scale ambiguity

Engineering Contradiction:
Improvedevice costVSAvoidpositional awareness accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent merges visual sensing (cameras) with inertial sensing (IMUs) into a unified visual-inertial system. The visual component provides cost-effective positioning but suffers from scale ambiguity and slow processing. The inertial component provides fast motion capture and scale information. By fusing these complementary systems, the patent achieves both low cost and high precision positional awareness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inertial measurement unit acts as an intermediary that bridges the gap between visual feature matching and accurate 3D positioning. The IMU provides motion data that helps resolve scale ambiguity in visual approaches and accelerates processing by providing direct motion measurements, thereby improving precision while maintaining the cost benefits of visual sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If marker based approaches are used for positional awareness, then measurement precision is improved, but adaptability deteriorates due to limited operational area

Engineering Contradiction:
Improvelocation recognition accuracyVSAvoiduseful operating area
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces marker-based positioning (which requires physical markers in the environment) with markerless visual-inertial positioning. The system uses natural visual features from grayscale and color images combined with inertial motion data to achieve accurate positioning without requiring any special markers or pre-configured environmental elements, thereby expanding the useful operating area to unlimited spaces.

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

4Adaptability or versatility

If RFID/WiFi approaches are used for positional awareness, then adaptability is improved, but measurement precision deteriorates and device cost increases

Engineering Contradiction:
Improveoperational flexibilityVSAvoidlocation accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces RFID/WiFi-based positioning (which uses wireless signal triangulation) with visual-inertial positioning. The visual-inertial system achieves superior accuracy by directly measuring visual features and inertial motion, while maintaining adaptability through markerless operation. This substitution eliminates the precision limitations of signal-based methods while keeping the system flexible and wireless.

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

Data Source

PatentUS20230071839A1Visual-Inertial Positional Awareness for Autonomous and Non-Autonomous Tracking
Publication Date: 2023.03.09 TRIFO INC
  • US20230071839A1 patent drawing
  • US20230071839A1 patent drawing
  • US20230071839A1 patent drawing

AI summary

The described positional awareness techniques employing visual-inertial sensory data gathering and analysis hardware with reference to specific example implementations implement improvements in the use of sensors, techniques and hardware design that can enable specific embodiments to provide positional awareness to machines with improved speed and accuracy.