Robot Cleaner Boundary Detection Using Structured Light

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Solution Overview

Problem

Current robot cleaners face challenges in accurately detecting boundaries between objects, such as the floor and walls or obstacles, which are crucial for safe navigation, due to variations in lighting and object materials, leading to potential collisions.

Innovation Solution

A method and system for a robot cleaner that uses a light projection unit to project patterned light, an image acquisition unit to capture images, and a controller to apply a mask for detecting brightness differences between regions, allowing for the identification of seed pixels and feature detection to determine boundaries between objects, thereby controlling the robot's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional image analysis methods are used to detect boundaries, then the system is simple, but boundary detection accuracy deteriorates due to lighting variations and object material differences

Engineering Contradiction:
Improveboundary detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a light projection unit as an intermediary device that projects structured light patterns onto the environment. This mediator actively illuminates boundaries between objects, creating high-contrast edges that are easily detectable by the image sensor, thereby significantly improving boundary detection accuracy without requiring complex image processing algorithms

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the illumination parameter by using active structured light projection instead of passive ambient light. By projecting specific light patterns and analyzing the reflected light, the system transforms the detection problem from one affected by varying ambient lighting conditions to one where the illumination is controlled and predictable, thereby improving detection accuracy

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the robot cleaner uses basic image capture without active light projection, then the device complexity is low, but the detection time increases and collision prevention capability deteriorates

Engineering Contradiction:
Improvedetection timeVSAvoiddevice complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by projecting structured light patterns onto the environment before the robot makes movement decisions. This pre-illumination of boundaries allows the image sensor to capture high-contrast edge information in advance, enabling faster boundary detection and reducing the time required for safe navigation decisions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces passive mechanical image capture with an active optical system that projects structured light. This substitution transforms the detection mechanism from relying on ambient light reflection to using controlled light projection and reflection analysis, significantly reducing detection time while maintaining relatively simple device architecture

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

3Reliability

If the robot cleaner does not use depth information from light patterns, then the system is simpler, but collision prevention capability deteriorates

Engineering Contradiction:
Improvecollision prevention capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent adds the depth dimension by analyzing the reflection patterns of projected structured light. By examining how the light patterns deform when reflected from surfaces at different distances and angles, the system extracts depth information that provides three-dimensional spatial awareness, significantly improving collision prevention capability

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

Solution Approach 2:

The patent implements feedback by continuously analyzing the reflected light patterns and using this information to adjust the robot's navigation in real-time. The system projects light, captures the reflection, processes the depth information, and uses this feedback loop to make immediate collision avoidance decisions, enhancing reliability

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

This approach enhances boundary detection accuracy, reduces detection time, and prevents collisions by specifying detection regions based on obstacles, while also providing more accurate depth information using the projected light pattern.

Implementation Method 1

a light projection unit (150) for downwardly projecting patterned light including a horizontal segment to an area in front of the main body (110)

Methodology Applied
Scientific EffectLight projection: Light

Implementation Method 2

an image acquisition unit (120) for acquiring an image of the cleaning area

Methodology Applied
Scientific EffectImage acquisition through light detection: Photography

Data Source

PatentUS9610691B2Robot cleaner and method for controlling the same
Publication Date: 2017.04.04 LG ELECTRONICS INC
  • US9610691B2 patent drawing
  • US9610691B2 patent drawing
  • US9610691B2 patent drawing

AI summary

A robot cleaner and a control method thereof according to the present disclosure select a seed pixel in an image of an area in front of a main body, obtain a brightness difference between an upper region and a lower region obtained by dividing a predetermined detection area including each of neighboring pixels of the seed pixel and select a pixel belonging to a detection area having a largest brightness difference as a pixel constituting the boundary between objects indicated in the image. Accordingly, the boundary between objects present within a cleaning area can be detected rapidly and correctly through an image.