ToF and Radar Sensor Fusion for 3D Human Tracking Near Robots

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Solution Overview

Problem

Existing automated manufacturing systems struggle with transforming 2D sensor data into real 3D information about objects or obstacles, leading to unnecessary machine stops and reduced productivity, while also being costly.

Innovation Solution

A fusion system combining data from multiple sensors, including time-of-flight (ToF) sensors and radar sensors, to provide a high-resolution 3D perception of the environment, enabling the detection and tracking of human activities and obstacles in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If 2D sensor data is used for obstacle detection, then the system complexity is reduced, but the measurement precision and reliability of 3D obstacle detection deteriorates

Engineering Contradiction:
Improvesensor system complexityVSAvoid3D obstacle detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms 2D sensor data into 3D spatial information by introducing depth estimation through stereo vision or time-of-flight measurements. This allows the system to achieve accurate 3D obstacle detection without requiring complex 3D sensor arrays, effectively adding a depth dimension to the detection capability while maintaining system simplicity.

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

Solution Approach 2:

The patent introduces machine learning algorithms as an intermediary that processes 2D sensor data and infers 3D obstacle characteristics. The ML model acts as a mediator between the simple 2D sensors and the complex 3D detection requirement, extracting depth and spatial information from 2D images through learned patterns.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If conventional 2D sensor systems are used, then the device cost is reduced, but the productivity deteriorates due to unnecessary machine stops

Engineering Contradiction:
Improvesensor system costVSAvoidmanufacturing productivity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent replaces complex mechanical 3D scanning systems with computationally intensive 2D sensor processing enhanced by machine learning. Instead of using expensive 3D laser scanners or multiple cameras, the system uses standard 2D sensors with ML-based depth estimation, substituting hardware complexity with software intelligence to maintain productivity.

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

Solution Approach 2:

The patent changes the processing parameters from direct 3D spatial measurement to 2D image feature analysis with inferred depth. By transforming the detection paradigm from measuring 3D coordinates directly to estimating depth from 2D patterns, the system achieves accurate obstacle detection at lower cost while avoiding false stops that reduce productivity.

Inventive Principle:
Principle #35Parameter changes

3Speed

If direct sensor data triggering is used, then the response speed is improved, but the reliability of collision avoidance deteriorates due to false positives

Engineering Contradiction:
Improveresponse speedVSAvoidcollision avoidance reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent performs preliminary classification and filtering of sensor data using machine learning before triggering safety responses. The ML model pre-processes the raw sensor input to distinguish between actual obstacles and false positives (such as reflective surfaces or transient objects), ensuring that only genuine threats trigger machine stops and maintaining both fast response and high reliability.

Inventive Principle:
Principle #10Preliminary 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

The system effectively reduces unnecessary machine stops by accurately detecting and classifying obstacles in 3D space, improving productivity and safety while being more cost-effective than traditional 3D scanner systems.

Implementation Method 1

combining one or more two-dimensional images obtained from a time-of-flight (ToF) sensor

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

combining one or more two-dimensional images obtained from a time-of-flight (ToF) sensor with contemporaneously obtained data from a radar sensor

Methodology Applied
Scientific EffectRadar: Radar

Data Source

PatentEP4283335B1Detection and tracking of humans using sensor fusion to optimize human to robot collaboration in industry
Publication Date: 2025.02.19 INFINEON TECHNOLOGIES AG
  • EP4283335B1 patent drawingFigure 1~2
  • EP4283335B1 patent drawingFigure 3
  • EP4283335B1 patent drawingFigure 4

AI summary

A method of detecting and tracking human activities in the vicinity of a robot comprises the step of combining one or more two-dimensional images obtained from a time-of-flight (ToF) sensor with contemporaneously obtained data from a radar sensor, to obtain fused sensor data, and further comprises detecting the presence of a human in the vicinity of the robot, based on the fused sensor data, and estimating direction of motion and speed of motion of the human, based on the fused sensor data. In some embodiments, the detecting and estimating are performed using a machine-learning model, the machine-learning model having been trained using two-dimensional ToF images and radar sensor data representative of an environment for the robot.