Construction Progress Measurement Using Building Element Depth Maps
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Solution Overview
Problem
Existing methods for comparing point clouds generated by 3D scanners with BIM models are complex and inaccurate, especially due to differences in gridding and lighting conditions, making detailed documentation of construction progress difficult.
Innovation Solution
Generate building element-specific depth maps using 3D scanner data and compare them with previously generated depth maps, utilizing graphics processors for efficient data management and comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 3D scanners are used to scan the structure regularly, then construction progress can be tracked, but the data volume increases and comparison accuracy decreases due to different gridding and lighting conditions
Solution Approach 1:
The patent segments the building into building elements and generates building element-specific depth maps from the point cloud data. This segmentation allows each building element to be compared independently, reducing the complexity of comparing entire point clouds while maintaining detailed monitoring capability.
Solution Approach 2:
The patent introduces depth maps as an intermediary representation between the raw point cloud data and the building model. These depth maps serve as a standardized intermediate format that normalizes the data from different scans, enabling accurate comparisons across multiple time points while reducing the data volume needed for analysis.
2Loss of information
If point clouds are generated from multiple scans, then construction progress can be documented, but the data volume and complexity increase significantly
Solution Approach 1:
The patent extracts only the essential depth information from the complex point cloud data by generating building element-specific depth maps. This extraction process discards redundant information while preserving the critical data needed for construction progress monitoring, significantly reducing the data volume required for documentation.
Solution Approach 2:
The patent creates a simplified copy of the building elements in the form of depth maps that represent the essential geometric information. These depth map copies are much smaller in size compared to the original point cloud data but contain sufficient information for accurate progress tracking and comparison.
3Measurement precision
If detailed comparison of point clouds is performed, then construction progress can be accurately recorded, but the computational effort and time increase considerably
Solution Approach 1:
The patent performs preliminary processing by generating building element-specific depth maps from the point cloud data before the actual comparison with the building model. This preliminary action prepares the data in an optimized format that is ready for efficient comparison, reducing the computational time needed for the actual progress assessment.
Solution Approach 2:
The patent changes the representation parameters from raw point cloud coordinates to building element-specific depth maps. This parameter transformation optimizes the data structure for comparison operations, enabling accurate progress measurement with significantly reduced computational effort and processing time.
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
Significantly reduces data volume for documentation and enhances the efficiency of construction progress monitoring by improving data compressibility and comparability, allowing for precise tracking of construction deviations.
Implementation Method 1
3D scanners, such as lidar or laser scanners
Implementation Method 2
3D scanners, such as lidar or laser scanners
Data Source
Figure 1
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Figure 4
AI summary
To measure construction progress, a digital building model (BM) is imported, based on which a spatial arrangement of a building element surface (F1,...,F4) is determined for each building element (BE1,...,BE4). Furthermore, the building (B) is scanned using a 3D scanner (S3D), generating a multitude of spatial scan points (P, P'). The scan points (P, P') are then at least partially assigned to spatially corresponding building element surfaces (F1,...,F4). According to the invention, a building element surface-specific texture (TX2) and/or depth map (DM2) is generated for each building element surface (F1,...,F4) based on the scan points (P, P') specifically assigned to that building element surface. To determine the construction progress, the generated textures (TX2) and/or depth maps (DM2) are then compared with previously generated textures (TX1) and/or depth maps (DM1).