Protective Field Segmentation for Secure Object Tracking

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Solution Overview

Problem

Current monitoring devices in security technology, such as safety laser scanners and cameras, lack the capability for secure and precise object tracking due to limitations in computational resources and the inability to access scan point clouds or depth maps securely, restricting their ability to provide fine positional accuracy for object tracking within safety-critical applications.

Innovation Solution

The solution involves configuring two protective fields into multiple partial protective fields, which are interlocked along a line, allowing for secure object tracking with increased resolution by evaluating the temporal sequence of safe output signals, analogous to incremental encoders, enabling discrete and precise position determination along one dimension and potentially expanding to two or three dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional object tracking algorithms are used in safety monitoring devices, then object tracking capability is provided, but the computational complexity and resource requirements exceed what is available in safety-certified systems

Engineering Contradiction:
Improveobject tracking capabilityVSAvoidcomputational resource requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the protective field into multiple partial protective fields arranged in a pattern, transforming the continuous space into discrete zones. This segmentation allows position determination through simple binary detection of which zone an object occupies, rather than requiring complex continuous coordinate calculation, thereby reducing computational complexity while maintaining tracking capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex computational algorithms with a simpler binary detection system. Instead of using resource-intensive image processing or Kalman filtering, the system uses binary sensors to detect which partial protective field an object occupies, substituting mechanical/digital detection with an optimized electrical/binary signal processing approach that is suitable for safety-certified embedded systems

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

2Reliability

If safety laser scanners or cameras are used for protective field monitoring, then safety compliance is achieved, but secure access to scan point clouds or depth maps for object tracking is not available

Engineering Contradiction:
Improvesafety complianceVSAvoidaccess to position data
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent performs preliminary segmentation of the protective field into partial protective fields before object detection occurs. By pre-defining discrete zones with binary detection capabilities, the system prepares the monitoring space in advance, allowing direct position determination from binary sensor outputs without requiring subsequent access to detailed scan point clouds or depth maps, thus maintaining safety compliance while enabling secure position information

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple protective fields are evaluated simultaneously, then more position classes are distinguishable, but the computational intensity increases and positioning accuracy remains limited

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcomputational intensity
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent divides the protective field into multiple partial protective fields with distinct spatial patterns, enabling fine position determination through binary detection. Each partial field represents a discrete position class, and the combination of binary sensor outputs directly encodes the object's position without requiring intensive computational processing, thus achieving high positioning accuracy with low computational power

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts only the essential position information needed for tracking by using binary detection of partial protective field violations. Instead of processing complete scan point clouds or depth maps, the system extracts minimal binary signals indicating which partial fields are violated, eliminating unnecessary computational intensity while maintaining precise position determination

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration allows for secure, high-resolution object tracking in one or multiple directions without requiring extensive computational resources, enhancing the safety functionality of monitoring devices and providing a finer grid for validation, thereby reducing potential errors in object tracking.

Implementation Method 1

a first safe optoelectronic sensor (10a, 10b) with a light receiver (26) that generates a received signal (22) from received light (16) from the surveillance area (18)

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

In a time-of-flight (TOF) camera, a scene is illuminated with amplitude-modulated light. The light returning from the scene is received and demodulated at the same frequency used to modulate the transmitted light (lock-in method). The demodulation results in an amplitude measurement value that corresponds to one sample of the received signal. According to the Nyquist criterion, at least two samples are necessary to determine the phase of a periodic signal. Therefore, the measurement is performed with different relative phase positions between the signals for the transmit-side modulation and the receive-side demodulation.This allows the absolute phase shift between the transmitted and received signals to be determined, which in turn is proportional to the object distance in the scene.

Methodology Applied
Scientific EffectTime of Flight: Time of Flight

Data Source

PatentEP4431985B1Secure object tracking of an object
Publication Date: 2024.12.25 SICK AG
  • EP4431985B1 patent drawingFigure 1~2
  • EP4431985B1 patent drawingFigure 3~4b
  • EP4431985B1 patent drawingFigure 5~6

AI summary

A monitoring device for the safe tracking of an object (20) in a monitoring area (18) is described, comprising at least one first safe optoelectronic sensor (10, 10a) and a safety controller (36) connected to the first optoelectronic sensor (10, 10a). The first optoelectronic sensor (10, 10a) monitors a first protective field (38A) and a second protective field (38B) for object intrusions and outputs a corresponding safe output signal at a first and second safe output (32), respectively. The safety controller evaluates the safe output signals. The first protective field (38A) has several first partial protective fields, and the second protective field (38B) has several second partial protective fields. The first partial protective fields and the second partial protective fields are arranged alternately along a line.