Fiducial Marker Alignment for BIM-Based Construction Deviation Detection

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Solution Overview

Problem

The construction process of complex structures, such as buildings, is prone to errors due to the laborious and time-consuming manual alignment of 3D scan images with computer models, leading to significant re-work, schedule delays, and increased costs, as discrepancies in component installation are often detected too late.

Innovation Solution

The method involves using fiducial markers to automate the alignment of image data from 3D physical structures with their corresponding computer models, enabling the detection of deviations and real-time correction by generating a transformation function based on control points and refining the alignment with 3D physical elements, thereby facilitating timely error detection and minimizing re-work.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual alignment of 3D scan images with computer models is performed, then construction progress can be monitored, but the process is laborious and time-consuming, leading to delays and increased costs

Engineering Contradiction:
Improvealignment accuracyVSAvoidalignment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Fiducial markers are pre-placed on the construction structure before scanning. These markers serve as predetermined reference points that enable automatic detection and alignment, eliminating the need for manual feature identification and significantly reducing alignment time while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a digital copy of the physical construction by scanning it and aligning the scan data with the BIM model. Fiducial markers are detected in both the physical world (in scan images) and the digital model, enabling automated correspondence establishment between real and virtual representations.

Inventive Principle:
Principle #26Copying

2Reliability

If manual alignment processes are used, then construction monitoring can be performed, but errors are detected too late, causing significant re-work and schedule delays

Engineering Contradiction:
Improveerror detection capabilityVSAvoidconstruction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system provides continuous feedback by automatically comparing scan data with the BIM model at frequent intervals. Deviations are detected and reported in real-time, enabling immediate corrective action before errors propagate through subsequent construction activities, thus maintaining both reliability and productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Errors are detected preliminarily through automated scanning and alignment before they become problematic. By continuously monitoring construction progress against the BIM model and identifying deviations early, the system prevents minor errors from escalating into major re-work scenarios.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If automated alignment using fiducial markers is implemented, then alignment speed and accuracy improve, but the complexity of the system increases due to marker placement and detection requirements

Engineering Contradiction:
Improvealignment speedVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Fiducial markers serve as intermediaries between the physical construction and the digital BIM model. These simple, standardized markers simplify the complex task of aligning two different representations by providing easily detectable, unambiguous reference points that bridge the physical-digital gap.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transforms the complex problem of 3D alignment into a simpler parameter-matching problem by detecting fiducial marker positions. Instead of aligning entire complex geometries, the system focuses on matching the coordinates of standardized marker features, significantly reducing computational and operational complexity.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If repetitive manual alignment is performed, then construction tracking can be maintained, but significant manual effort is required for each alignment operation

Engineering Contradiction:
Improvetracking accuracyVSAvoidoperational simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The alignment system performs self-service by automatically detecting fiducial markers in scan images and computing alignment transformations without human intervention. The system autonomously completes the entire alignment process from data acquisition to result generation, eliminating repetitive manual operations while maintaining high tracking accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical alignment process is replaced with an automated computational system. Instead of physically manipulating and visually aligning models, the system uses algorithmic detection of fiducial markers and mathematical transformation computations to achieve alignment, substituting manual mechanical operations with automated information processing.

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

Data Source

PatentUS11348322B1Tracking an ongoing construction by using fiducial markers
Publication Date: 2022.05.31 DOXEL INC
  • US11348322B1 patent drawing
  • US11348322B1 patent drawing
  • US11348322B1 patent drawing

AI summary

The disclosed embodiments include a method for automating alignment of image data captured of a three-dimensional (3D) physical structure with a computer model of the 3D physical structure. The method can include obtaining two-dimensional (2D) images of the 3D physical structure undergoing construction, detecting fiducial markers corresponding to control points in the 2D images, and determining a transformation function based on the control points. The method can further include obtaining more 2D images, detecting other fiducial markers, and aligning image data to a computer model by utilizing the transformation function. The method can further include refining an alignment by utilizing a refinement transformation based on 3D physical elements of the 3D physical structure.