Occupied Map Construction Using Incident-Angle Validation
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Solution Overview
Problem
Existing simultaneous localization and mapping (SLAM) techniques using laser scanners for mobile robots often inaccurately detect objects due to shallow emission angles, leading to erroneous object determination and reduced map accuracy.
Innovation Solution
An information processing device for mobile robots that includes a detection section, a control section, and a map construction section with a normal line acquirer and validity determinator to assess the validity of detection information based on incident angles, constructing an occupied map by reflecting the validity of each determination point, thereby reducing erroneous object detection and improving map accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser scanner is used to detect objects in the movement area, then detection information can be acquired for constructing an occupied map, but erroneous determination occurs when the emission angle of the beam is shallow, leading to reduced map accuracy
Solution Approach 1:
The patent changes the parameter of beam emission angle to identify and filter out shallow angle detections. By calculating the incident angle between the beam and the object surface normal, the system distinguishes valid detections from erroneous ones caused by shallow angles, thereby improving map accuracy while maintaining detection coverage
Solution Approach 2:
The patent introduces an intermediary validation process that acts as a mediator between raw detection data and the final occupied map. The validation section calculates incident angles and determines detection validity, filtering out unreliable detections before they corrupt the map, thus resolving the contradiction between comprehensive detection and accurate mapping
2Area of stationary object
If the laser scanner emits beams to detect objects at various angles, then the coverage area is expanded, but shallow angle emissions cause erroneous determination that objects are absent
Solution Approach 1:
The system maintains wide detection coverage by emitting beams at various angles but introduces a parameter-based filter (incident angle threshold) to eliminate erroneous determinations. Validations are performed by comparing the calculated incident angle against predefined thresholds, allowing the system to keep broad coverage while rejecting shallow angle false negatives
Solution Approach 2:
The detection process is segmented into multiple stages: initial detection with wide angular coverage, incident angle calculation, validity determination based on angle thresholds, and final map construction using only validated detections. This segmentation allows the system to maintain comprehensive coverage while ensuring accuracy through selective validation
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 effectively eliminates erroneous object detection and enhances map accuracy by using the information processing device to assess and validate detection data from mobile robots, ensuring accurate object sensing and mapping even at shallow angles.
Implementation Method 1
the laser scanner acquires the presence or absence of the object as the detection information according to return of a laser beam emitted from the laser scanner and reflected on an object surface or a road surface
Data Source
AI summary
An information processing device includes a detection section configured to acquire the presence or absence of an object at the periphery of a mobile robot as the detection information, a control section configured to control the detection section, and a map construction section configured to construct an occupied map. The map construction section includes a storage configured to store the detection information in chronological order, a map producer configured to produce a map based on the detection information, a normal line acquirer configured to acquire a normal line to each determination point based on the presence or absence of the object at the periphery of each determination point on the temporal map produced by the map producer, and a validity determinator configured to determine the validity of the detection information on each determination point based on an angle between each beam and the normal line at each determination point.