3D Shelf Obstruction Detection for Mixed-Depth Object Positioning

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Solution Overview

Problem

The varying structure of shelves in environments such as retail facilities complicates object detection, reducing the accuracy of status information detected from captured data, particularly when shelf edges have mixed depths, affecting the precision of identifying objects and obstructions.

Innovation Solution

A method involving a mobile automation apparatus equipped with image and depth sensors that generates three-dimensional positions of objects by projecting two-dimensional boundaries into point clouds, and detects obstructions directly from point clouds using local support structure planes, employing cost functions to refine object positions and identify obstructions robustly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional object detection methods are used on captured data, then the detection process is simple, but the accuracy of status information is reduced due to varying shelf structures and mixed depths

Engineering Contradiction:
Improveaccuracy of status informationVSAvoidcomplexity of detection method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms two-dimensional image data into three-dimensional point cloud data, adding a depth dimension to the detection process. This dimensional transformation enables accurate representation of objects on shelves with varying depths and mixed structures, resolving the accuracy issue while maintaining manageable system complexity through software-based processing.

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

Solution Approach 2:

The patent changes the detection parameters by introducing depth information and three-dimensional spatial coordinates. By transforming from 2D image coordinates to 3D point cloud coordinates with depth values, the system can accurately detect objects on shelves with mixed depths, significantly improving measurement precision without requiring complex hardware modifications.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If 3D position generation from 2D boundaries is implemented, then object position accuracy is improved, but the processing complexity increases

Engineering Contradiction:
Improveprecision of object positionsVSAvoidcomplexity of processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary coordinate transformation process that maps 2D image boundaries to 3D point cloud positions through depth information. This intermediary step uses the known camera parameters and point cloud depth data to calculate accurate 3D positions, improving precision while keeping processing complexity manageable through systematic mathematical transformations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary actions by first capturing both 2D images and 3D point cloud data simultaneously, then pre-processing the point cloud to identify shelf structures and depth information before generating object positions. This preliminary preparation of spatial data enables accurate 3D position generation without requiring complex real-time processing during object detection.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If detection accuracy is improved through 3D point cloud analysis, then the reliability of product status monitoring is enhanced, but the computational requirements and processing time increase

Engineering Contradiction:
Improvereliability of product status monitoringVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the detection process into distinct stages: point cloud acquisition, shelf structure identification, object boundary detection, and position calculation. By dividing the complex 3D detection task into manageable segments, the system achieves high reliability in product status monitoring while reducing overall processing time through parallel processing of different detection stages.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by focusing detection efforts on relevant regions identified in the 2D image boundaries, rather than processing the entire point cloud. By limiting 3D position generation to only those areas where objects are detected in 2D, the system maintains high reliability for monitored products while significantly reducing unnecessary computational overhead and processing time.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12579686B2Mixed depth object detection
Publication Date: 2026.03.17 ZEBRA TECHNOLOGIES CORP
  • US12579686B2 patent drawing
  • US12579686B2 patent drawing
  • US12579686B2 patent drawing

AI summary

A method includes obtaining (i) a point cloud, captured by a depth sensor, of a structure and an obstruction, and (ii) a plurality of local structure planes derived from the point cloud and corresponding to respective portions of the structure, for each local structure plane: selecting a membership set of points from the point cloud, generating a mask based on the membership set of points, selecting a subset of points from the point cloud based on the local structure plane and the mask, and detecting obstructions from the subset of points.