Lidar Reflection Clustering for False-Positive Detection Filtering

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Solution Overview

Problem

Lidar sensors in vehicles often produce false-positive detections due to reflective materials like window panes, leading to potential dangerous interventions in automated driving systems, as they incorrectly measure distances and create phantom objects.

Innovation Solution

A method and device that check for laser pulses reflected multiple times at different distances, cluster initial reflections, and mark further reflections as false-positive if they occur on approximately homogeneous surfaces, particularly at larger distances, to differentiate between real and phantom targets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lidar sensor scans all reflected laser pulses to detect objects, then detection coverage is improved, but false-positive detections increase due to reflective materials

Engineering Contradiction:
Improvedetection accuracyVSAvoidfalse-positive detections
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the detection process into distinct phases: identifying first reflections, clustering them to define regions, and then evaluating subsequent reflections against these regions. This segmentation allows the system to differentiate between valid objects and phantom targets caused by reflective materials like window panes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary clustering of first reflections before evaluating further reflections. By pre-defining regions based on initial reflections and their spatial relationships, the system establishes a reference framework that enables rapid identification and filtering of false positives from reflective surfaces.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If lidar sensor marks all further reflections as potential targets, then detection sensitivity is improved, but reliability decreases due to phantom targets

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidoperation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the characteristics of first reflections (clustering, spatial distribution, distance relationships) are used to evaluate and validate subsequent reflections. This feedback loop enables the system to confirm or reject potential targets based on consistency with previously established reflection patterns, thereby improving both precision and reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes evaluation parameters based on reflection order and spatial relationships. First reflections are clustered to establish baseline parameters (region boundaries, distance ranges), while further reflections are evaluated against these parameters with additional criteria (whether they fall within clustered regions, their distance relative to first reflections). This dynamic parameter adjustment improves measurement precision while filtering phantom targets.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If lidar sensor differentiates between various cluster types, then classification accuracy is improved, but processing complexity increases

Engineering Contradiction:
Improvecluster classification accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality analysis by examining specific geometric properties of reflection clusters (planar surfaces, curved surfaces, extension in one or three spatial directions) rather than treating all clusters uniformly. This localized approach enables accurate classification of different target types (edges, dust/fog, volumetric objects) while keeping processing complexity manageable through focused feature extraction.

Inventive Principle:
Principle #3Local quality

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 approach significantly increases the reliability of lidar sensor operations in real traffic scenarios, preventing false interventions and enhancing the safety of automated and autonomous driving systems by accurately distinguishing between real and phantom detections.

Implementation Method 1

for every laser pulse that is reflected back to the lidar sensor in a scan range of this, it is checked whether this is reflected back several times in different distances

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

laser pulse that is reflected back several times

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentUS20230366994A1Method and device for determining false-positive detections of a lidar sensor
Publication Date: 2023.11.16 MERCEDES BENZ GROUP AG
  • US20230366994A1 patent drawing
  • US20230366994A1 patent drawing
  • US20230366994A1 patent drawing

AI summary

A method for determining false-positive detections of a lidar sensor in a scanning process of the surroundings of a vehicle involves, for every laser pulse that is reflected back to the lidar sensor in a scan range of this, checking whether this is reflected back several times in different distances. First reflections of a laser pulse that is reflected back several times are clustered and then, if a distance evaluation of reflections from the cluster produced reveals that the laser pulses are being reflected at a reflecting surface that is at least approximately homogeneous, further reflections following the respective first reflection are marked as false-positive detections.