Optoelectronic Sensor Inclined Image Sensor for Distance-Dependent Focus

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Solution Overview

Problem

Existing optoelectronic sensors face challenges in achieving sharp image recording across varying distances without complex focus adjustments, especially when combining laser scanners and camera systems, as they require different technical processes that are difficult to coordinate effectively.

Innovation Solution

An optoelectronic sensor with a camera module and time-of-flight measurement module integrated in a rotating scanning unit, where the image sensor is optically inclined to provide different effective optical path lengths for each receiving line, allowing for complementary depths of field without dynamic focus adjustment, and a control unit coordinates image data with distance information for optimal image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a camera system is used to capture images from different positions, then the coverage area is increased, but the system complexity and bulkiness increase significantly

Engineering Contradiction:
Improvecoverage areaVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines a laser scanner and a camera system into a single integrated sensor unit that rotates together. This merging allows both distance measurement and image capture to occur from the same positions, increasing coverage area while avoiding the complexity of separate moving camera systems. The integration means the camera and laser scanner share the same rotational mechanism and coordinate system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotating sensor unit serves multiple functions simultaneously: it performs both time-of-flight distance measurement and image capture across a wide area. This multi-functionality eliminates the need for separate dedicated camera systems positioned elsewhere, reducing overall system complexity while maintaining comprehensive coverage.

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

2Manufacturing precision

If the focus position is adjusted for different object distances, then image quality is improved, but the device complexity increases due to moving focus adjustment parts

Engineering Contradiction:
Improveimage qualityVSAvoidfocus adjustment mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic focus adjustment that automatically adapts to different object distances based on the rotational position and measured distance data. The focus position changes continuously as the sensor rotates and detects objects at varying ranges, optimizing image quality without requiring manual intervention or complex mechanical focus mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the time-of-flight distance measurements to automatically adjust the focus position of the camera. The measured distance to objects provides real-time information that controls the focus adjustment, creating a closed-loop system that maintains sharp images across varying distances without adding mechanical complexity.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If a rotating camera system is used to cover larger areas, then the monitoring capability is improved, but the coordination of mirror movement and image capture becomes very complex

Engineering Contradiction:
Improvemonitoring capabilityVSAvoidcoordination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the camera system with the laser scanner's rotational mechanism, so both components rotate together as a single unit. This eliminates the need for separate mirror movement coordination and image capture timing that plagues rotating camera systems. The integrated design means both sensors observe the same scene from the same position, greatly simplifying coordination.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex mechanical mirror movement systems with a direct rotational mounting of the camera and laser scanner. Instead of using mirrors to redirect light paths in rotating camera systems, this design allows the camera to directly view the scene as it rotates, eliminating the mechanical complexity of mirror coordination while maintaining wide-area monitoring capability.

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

4Manufacturing precision

If high-resolution cameras are used to cover large distance ranges, then the image resolution is improved, but the focus adjustment becomes impossible at typical laser scanner angular velocities

Engineering Contradiction:
Improveimage resolutionVSAvoidfocus adjustment speed
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The patent implements dynamic focus adjustment that operates at the same high speeds as the laser scanner's rotation. The focus mechanism is designed to respond to changing object distances in real-time during rapid rotation, maintaining high-resolution image capture despite the fast angular velocities that would normally make focus adjustment impossible.

Inventive Principle:
Principle #15Dynamics

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

Enables high-quality image capture across all distance ranges with reduced manufacturing costs and data processing, eliminating the need for moving focus adjustment parts and complex data fusion, allowing for fast evaluation and high clock frequency.

Implementation Method 1

a light beam generated by a laser

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

The light is reflected by objects in the scanning plane

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

the time-of-flight measurement module (22) has a light transmitter (26) for emitting transmitted light and a light receiver (36) for receiving the transmitted light reflected by objects in the monitoring area (20)

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 4

an image sensor (44) with several receiving lines (44a-d) aligned parallel to the axis of rotation (18)

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3736603B1Optoelectronic sensor and method for detecting a monitored area
Publication Date: 2021.09.29 SICK AG
  • EP3736603B1 patent drawingFigure 1
  • EP3736603B1 patent drawingFigure 2
  • EP3736603B1 patent drawingFigure 3~5

AI summary

An optoelectronic sensor (10) for monitoring a monitoring area (20) is described, comprising a scanning unit (12) movable about a rotational axis (18) for periodically scanning the monitoring area (20), a camera module (24) arranged in the scanning unit (12) with a receiving optic (42) and an image sensor (44) with at least two receiving lines (44a-c) of light receiving elements, and a control and evaluation unit (48) for reading out image data from the image sensor (44). The image sensor (44) is optically inclined in the direction of the optical axis of the camera module (24) so ​​that the optical path lengths from the receiving optic (42) to the respective receiving lines (44a-c) differ.