3D Feature Tracking in SLAM Using LK-SURF and Hierarchical State Spaces

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Solution Overview

Problem

Current SLAM techniques face challenges in constructing and using perceptually rich maps, especially in large-scale and complex environments, due to algorithmic complexity, consistency issues, and difficulties with loop-closing detection and feature matching, particularly in GPS-denied areas with 3D motions and sensor noise.

Innovation Solution

The implementation of LK-SURF, Robust Kalman Filter, HAR-SLAM, and Landmark Promotion SLAM methods, which combine Lucas-Kanade feature tracking with Speeded-Up Robust Features, Principal Component Analysis, and hierarchical SLAM architectures to improve feature tracking, outlier rejection, and map generation in real-time, using inexpensive sensors and promoting reliable landmarks through multiple layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional SLAM techniques are used to construct perceptually rich maps in large-scale environments, then mapping capability is improved, but algorithmic complexity increases significantly

Engineering Contradiction:
Improvemapping capabilityVSAvoidalgorithmic complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the SLAM problem into distinct modules: feature extraction, feature tracking, loop detection, and map construction. Each module handles specific tasks independently, reducing overall algorithmic complexity while maintaining mapping capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional 2D feature tracking to 3D feature tracking by incorporating depth information from RGB-D sensors. This dimensional enhancement improves mapping capability in large-scale environments without proportionally increasing complexity.

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

2Productivity

If 3D features are tracked and mapped in real-time, then mapping speed is improved, but computational requirements increase

Engineering Contradiction:
Improvemapping speedVSAvoidcomputational requirements
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the most salient 3D features for tracking and mapping, rather than processing all visual data. This selective extraction maintains real-time mapping speed while reducing computational requirements by focusing on key features.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses lightweight feature representations and approximate algorithms that consume minimal computational resources, enabling real-time 3D feature tracking with inexpensive sensors rather than requiring heavy computational infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If multiple sensors and tracked objects are incorporated into SLAM, then system versatility is improved, but state space complexity increases

Engineering Contradiction:
Improvesystem versatilityVSAvoidstate space complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal feature tracking framework that can handle multiple sensor types (RGB-D cameras, LiDAR) and multiple tracked objects using the same core algorithms. This multi-functional approach improves system versatility without requiring separate complex state spaces for each sensor or object.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11140379B2Mapping and tracking system with features in three-dimensional space
Publication Date: 2021.10.05 TRX SYST
  • US11140379B2 patent drawing
  • US11140379B2 patent drawing
  • US11140379B2 patent drawing

AI summary

LK-SURF, Robust Kalman Filter, HAR-SLAM, and Landmark Promotion SLAM methods are disclosed. LK-SURF is an image processing technique that combines Lucas-Kanade feature tracking with Speeded-Up Robust Features to perform spatial and temporal tracking using stereo images to produce 3D features can be tracked and identified. The Robust Kalman Filter is an extension of the Kalman Filter algorithm that improves the ability to remove erroneous observations using Principal Component Analysis and the X84 outlier rejection rule. Hierarchical Active Ripple SLAM is a new SLAM architecture that breaks the traditional state space of SLAM into a chain of smaller state spaces, allowing multiple tracked objects, multiple sensors, and multiple updates to occur in linear time with linear storage with respect to the number of tracked objects, landmarks, and estimated object locations. In Landmark Promotion SLAM, only reliable mapped landmarks are promoted through various layers of SLAM to generate larger maps.