Homogeneous Transformation Matrix for 3D Motion Tracking

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Solution Overview

Problem

Conventional 2D image systems struggle to accurately calculate the translation and rotation of objects in 3D space due to the projection of data onto a flat plane, making it difficult to track motion in three-dimensional environments effectively.

Innovation Solution

A low-resolution motion tracking technique that incorporates 3D imaging data to estimate a homogeneous transformation matrix, improving the accuracy of motion tracking by using a combination of optical flow and 3D data to characterize object movement over time, and creating 3D digital models of the scene.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional 2D image systems are used to track motion, then the system is simple and easy to operate, but the measurement precision of 3D translation and rotation is poor

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from 2D image capture to 3D imaging by incorporating depth information through time-of-flight measurements. The system captures both 2D image data and 3D depth data, then fuses these multi-dimensional data streams to achieve accurate 3D motion tracking. This dimensionality change enables precise measurement of translation and rotation in three-dimensional space while maintaining system feasibility.

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

Solution Approach 2:

The patent combines multiple data sources including 2D image data from conventional cameras, 3D depth data from time-of-flight sensors, and motion tracking information from inertial measurement units. By merging these diverse data streams and processing them through integrated algorithms, the system achieves high-precision 3D motion tracking that overcomes the limitations of individual 2D systems.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If 3D imaging data is incorporated to improve motion tracking accuracy, then the measurement precision improves, but the processing complexity and computational requirements increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary processing of 3D imaging data by extracting key features and constructing preliminary 3D models before full motion analysis. Depth information from time-of-flight sensors is pre-processed to identify significant spatial features, reducing the computational burden during subsequent motion tracking operations. This preliminary action enables accurate 3D motion measurement while managing processing complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs self-calibration and automatic feature matching algorithms that reduce the need for manual intervention and complex external processing. The 3D imaging system automatically adjusts parameters and refines measurements based on incoming data streams, enabling the system to serve itself in maintaining high measurement precision without proportionally increasing operational complexity.

Inventive Principle:
Principle #25Self-service

3Productivity

If low-resolution motion tracking is used to estimate transformation matrix, then the processing speed is fast, but the accuracy of motion characterization is insufficient

Engineering Contradiction:
Improveprocessing speedVSAvoidaccuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic processing architecture that adapts resolution and processing intensity based on motion characteristics. During high-speed motion events, the system uses lower resolution tracking to maintain processing speed. During stationary or slow-motion periods, the system switches to high-resolution 3D imaging for accurate characterization. This dynamic switching enables both fast processing speed and high measurement precision at different operational phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic sampling at different resolution levels. Low-resolution tracking operates continuously at high frame rates to capture fast motion events, while high-resolution 3D imaging is periodically activated to refine measurements and update the transformation matrix. This periodic alternation between resolution levels maintains both processing speed and accuracy.

Inventive Principle:
Principle #19Periodic action

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 the accuracy of motion tracking and 3D image acquisition, enabling better characterization of object motion and scene representation, particularly in large areas, and allows for real-time, high-precision tracking without the need for human operators, as demonstrated by the use of mobile robotic platforms.

Implementation Method 1

Optical flow and its derivatives can be used to track the motion of an object. In optical flow, motion is calculated by comparing successive two-dimensional (referred to herein, alternatively, as '2-dimensional' or '2-D') images.

Methodology Applied
Scientific EffectOptical flow:

Data Source

PatentUS10706565B2Method and apparatus for motion tracking of an object and acquisition of three-dimensional data over large areas
Publication Date: 2020.07.07 SAVTEQ INC
  • US10706565B2 patent drawing
  • US10706565B2 patent drawing
  • US10706565B2 patent drawing

AI summary

A multi-dimensional solution directed to employment of a low-resolution motion tracking technique to estimate a homogeneous transformation matrix that is further adapted to accurately characterize movement/motion between successive positions of an object through time. Low-resolution tracking is first used to estimate a homogeneous transformation matrix that describes the motion between successive positions of an object as that object moves over time. The 3-dimensional imaging data is then used to calculate a more accurate homogeneous transformation matrix, providing the accuracy to better characterize motion of the object over time. In the case where the ‘object’ being tracked is a 3-dimensional imaging system (herein, 3DIS), the resulting homogeneous transformation matrix is used to create 3-dimensional digital models of the scene that is in the field-of-view of the 3-dimensional imaging system (3DIS).