Traversable Object Classification Using Free Space Probability Differences

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Solution Overview

Problem

Current advanced driver assistance systems (ADAS) struggle to distinguish between traversable and non-traversable objects without height information, as 2D radars do not provide necessary elevation measurements, leading to incorrect environmental understanding.

Innovation Solution

A device comprising an object-detection sensor unit, a map generation unit, and a classifier unit that generates occupancy and free space grid maps, allowing classification of cells as traversable or non-traversable by calculating differences in free space probability values from adjacent cells, without relying on height information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If 2D radar is used for object detection, then cost is reduced, but height information is lost leading to inability to distinguish traversable objects

Engineering Contradiction:
ImprovecostVSAvoidheight information
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent introduces map data as an intermediary that provides height information about objects. Instead of directly measuring height with expensive 3D radar, the system uses pre-existing map data (from satellite imagery, aerial photography, or other sources) that contains elevation information. This map data acts as a mediator that bridges the gap between the inexpensive 2D radar and the need for height information, allowing the system to distinguish traversable objects like curbs without using costly 3D sensing hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If 3D radar with full resolution vertical angle is used, then height information is obtained for distinguishing traversable objects, but device cost increases

Engineering Contradiction:
Improveheight informationVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses map data as a copy or representation of the real-world environment's height information. Instead of directly measuring heights with 3D radar, the system creates a digital copy of elevation data from map sources (satellite imagery, aerial photography) and uses this copied information for classification. This allows the system to obtain height information indirectly through data copying rather than direct physical measurement, significantly reducing hardware costs while maintaining classification accuracy.

Inventive Principle:
Principle #26Copying

3Reliability

If any radar detection is interpreted as non-traversable obstacle, then safety is improved by avoiding all detected objects, but wrong environmental understanding occurs

Engineering Contradiction:
ImprovesafetyVSAvoidenvironmental understanding
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the classification process into two distinct stages: first detecting objects with radar, then classifying them as traversable or non-traversable using map data. Instead of treating all detections uniformly as obstacles, the system divides the problem into detection and classification phases. This segmentation allows the system to maintain safety by detecting all objects while avoiding false positives, because the classification step correctly identifies traversable objects like curbs that should not be treated as hazardous obstacles.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3460516B1A device and a method for distinguishing between traversable and non-traversable objects
Publication Date: 2020.05.27 APTIV TECHNOLOGIES LTD
  • EP3460516B1 patent drawingFigure 1~2B
  • EP3460516B1 patent drawingFigure 3~5
  • EP3460516B1 patent drawingFigure 6

AI summary

A device for distinguishing between traversable and non-traversable objects, comprising: an object-detection sensor unit configured to monitor a space around the object-detection sensor unit and to generate data about the space, a map generation unit configured to use the data generated by the object-detection sensor unit in order to generate an occupancy grid map and a free space grid map for the space around the object-detection sensor unit, wherein each of the occupancy grid map and the free space grid map comprises an array of cells, each cell of the occupancy grid map contains an occupied space probability value representing the probability for the respective cell being occupied and each cell of the free grid map contains a free space probability value representing the probability for the respective cell being free, and a classifier unit configured to classify at least one of the cells as containing a traversable or non-traversable object by calculating a difference of two free space probability values derived from the free space probability values of at least two of the cells adjacent to the at least one cell and by using the difference as well as the occupied space probability value of the at least one cell in order to classify the at least one cell.