3D Camera Self-Testing via Internal Reference Target

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Solution Overview

Problem

Current safety technology applications in industrial environments, such as 3D cameras, lack reliable and efficient methods for self-monitoring and meeting safety standards, particularly in complex automation tasks, due to limitations in conventional sensors and the absence of secure 3D cameras that can effectively implement high safety levels.

Innovation Solution

A camera system with a scanning unit that moves about an axis of rotation, incorporating an internal reference target for self-testing, allows for the generation of three-dimensional image data and functionality checks, enabling reliable cyclic function testing and increased safety levels while avoiding interactions between normal operation and self-testing, and providing a larger field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional safety sensors (light curtains, laser scanners) are used, then safety functions are provided, but the ability to protect complex automation tasks and geometries is limited

Engineering Contradiction:
Improveability to protect complex automation tasksVSAvoidsafety reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies multi-functionality by enabling the camera system to serve both normal 3D imaging operations and safety monitoring functions through the same hardware platform. The image sensor captures both scene information and reference target information, while the processor distinguishes between normal operation mode and self-test mode, allowing a single system to fulfill multiple roles including safety-critical functions

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

2Reliability

If additional reference light sources are used for self-testing, then functionality checks are enabled, but the actual measurement must be interrupted cyclically

Engineering Contradiction:
Improvefunctionality check capabilityVSAvoidmeasurement continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic action by cyclically switching the image sensor between normal operation mode and self-test mode. The sensor periodically captures reference target information instead of scene information at predetermined intervals, enabling continuous functionality checks without requiring separate test equipment or permanent measurement interruptions

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent maintains continuity of useful action by performing self-tests during normal operation through periodic sampling. The system continuously monitors its own functionality by intermittently capturing reference target images alongside normal scene images, ensuring both measurement continuity and reliability verification without stopping the measurement process

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If a reference target is detected in a rear dead zone of scanning movement, then self-test is possible, but this cannot be used for a camera due to lack of scanning movement

Engineering Contradiction:
Improveself-test capabilityVSAvoidscanning mechanism requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical scanning system with a computational approach. Instead of physically rotating the camera or using moving parts to create a dead zone for reference target detection, the system uses image processing algorithms to identify and extract reference target information from the captured image data, eliminating the need for mechanical scanning components

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

4Reliability

If the camera is designed as a secure 3D camera, then safety levels are increased, but range, size, and costs increase significantly

Engineering Contradiction:
Improvesafety levelVSAvoidcamera system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges safety monitoring functions with normal 3D imaging functions into a single integrated camera system. The same image sensor, illumination unit, and processor are used for both normal operation and safety-critical self-testing, combining multiple functions into one device to avoid the complexity and cost of separate safety systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements self-service by enabling the camera system to monitor and verify its own functionality autonomously. The system performs self-tests by detecting reference targets and evaluating whether captured information matches expected reference information, allowing the camera to self-diagnose and ensure its own safety reliability without external monitoring equipment

Inventive Principle:
Principle #25Self-service

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 solution enables reliable and simple implementation of higher safety levels in camera systems, overcoming limitations of conventional cameras by allowing for extensive self-testing and larger field views, ensuring camera functionality and safety standards are met, thereby preventing accidents.

Implementation Method 1

an illumination unit for emitting transmitted light (16) that is modulated in particular with at least one modulation frequency

Methodology Applied
Scientific EffectLight modulation: Phase Modulation

Implementation Method 2

an image sensor (24) with a plurality of light receiving elements or pixels (24a) for detecting light signals reflected by objects

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 3

the control and evaluation unit being designed to generate the three-dimensional image data using a time-of-flight method

Methodology Applied
Scientific EffectTime of flight measurement: Time of Flight

Data Source

PatentEP4116733A1Three-dimensional image data acquisition camera and method for verifying camera functionality
Publication Date: 2023.01.11 SICK AG
  • EP4116733A1 patent drawingFigure 1
  • EP4116733A1 patent drawingFigure 2
  • EP4116733A1 patent drawingFigure 3

AI summary

A camera (10) for capturing three-dimensional image data from a detection area (18) is provided. The camera comprises an image sensor (24) with a plurality of light-receiving elements (24a) for generating a respective received signal, a reference target (44), and a control and evaluation unit (26) configured to generate three-dimensional image data from the received signals and to verify the functionality of the camera (10) based on received signals generated during the detection of the reference target (44) by at least some of the light-receiving elements (44a). The camera (10) has a scanning unit (28) movable about a rotational axis, in which the image sensor (24) is housed, and the reference target (44) is arranged such that it is detected in a reference position of the scanning unit (28).