Vehicle Sensor System Resolving Ground Obstacle Detection

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Solution Overview

Problem

Existing optical sensor systems for vehicles, including self-driving ones, often fail to detect obstacles close to the ground due to their arrangement, leading to potential collisions and safety risks, especially when the vehicle undergoes pitching movements or encounters bumps.

Innovation Solution

Incorporating a depth camera that generates three-dimensional images and adjusts a reference contour based on acceleration-dependent movements, combined with a distance sensor, to enhance obstacle detection and reduce errors, allowing for better recognition of objects both above and below the monitoring area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the distance sensor is arranged at a distance from the ground to avoid erroneous detection during pitching movements, then false detection of ground as obstacle is avoided, but obstacles close to the ground are not detected

Engineering Contradiction:
Improveavoid false detectionVSAvoiddetection of close obstacles
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The monitoring area is divided into two segments: a first monitoring area for flat surfaces parallel to ground (detected by distance sensor) and a second monitoring area for areas below the flat surface (detected by depth camera). This segmentation allows each sensor to focus on specific zones, resolving the contradiction between avoiding false detection and detecting close obstacles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from two-dimensional flat surface monitoring (distance sensor) to three-dimensional volume monitoring (depth camera). The depth camera captures depth information in the vertical dimension below the flat surface, enabling detection of obstacles that would be missed by traditional distance sensors positioned to avoid ground detection errors.

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

2Measurement precision

If the distance sensor scans a line-shaped area parallel to ground, then flat surfaces are monitored effectively, but obstacles below the monitoring area are missed

Engineering Contradiction:
Improveflat surface monitoringVSAvoidobstacle detection completeness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system merges the functionality of a distance sensor (for flat surface monitoring) with a depth camera (for volumetric obstacle detection). The evaluation unit combines data from both sensors, maintaining effective flat surface monitoring while adding comprehensive obstacle detection capability below the monitoring area.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a depth camera is added to detect obstacles below the monitoring area, then obstacle detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The depth camera serves multiple functions: detecting obstacles below the monitoring area, providing depth information for the evaluation unit, and working in conjunction with the distance sensor to create a comprehensive monitoring system. This multi-functionality justifies the added complexity by delivering significant performance improvements.

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

Solution Approach 2:

The evaluation unit acts as an intermediary that processes and integrates data from both the distance sensor and depth camera. It combines the line-shaped area data from the distance sensor with the three-dimensional image data from the depth camera, resolving the complexity of managing multiple sensors through centralized intelligent processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If the reference contour is adjusted based on acceleration values, then detection accuracy during vehicle movement is improved, but processing complexity increases

Engineering Contradiction:
Improvedetection accuracy during movementVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system implements feedback by continuously monitoring acceleration values and using them to adjust the reference contour in real-time. The evaluation unit receives acceleration data, processes it to determine vehicle movement state, and dynamically adapts the reference contour accordingly, maintaining high detection accuracy during pitching movements while using straightforward processing logic.

Inventive Principle:
Principle #23Feedback

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 combination of distance sensors and depth cameras improves obstacle detection accuracy and reduces errors, enabling safer vehicle operation by identifying flat obstacles and adapting to movement-induced changes, thus preventing collisions and enhancing safety.

Implementation Method 1

The depth camera is preferably a TOF camera (i.e. a time-of-flight camera or a camera with time-of-flight measurement)

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

a laser scanner, which determines distance information for a first monitoring area

Methodology Applied
Scientific EffectLIDAR: LIDAR

Data Source

PatentEP3026459B1Sensor system
Publication Date: 2018.12.12 SICK AG
  • EP3026459B1 patent drawingFigure 1~2
  • EP3026459B1 patent drawingFigure 3~4

AI summary

The invention relates to an optical sensor system with a distance sensor, in particular a laser scanner, which determines distance information for a first monitoring area, wherein the first monitoring area defines a flat surface that preferably runs parallel to a surface. The sensor system further comprises an evaluation unit configured to recognize objects based on the distance information and to output a warning signal upon detection of an object, wherein the sensor system additionally comprises a depth camera that generates a three-dimensional image of a second monitoring area.