Photogrammetry for 3D Reconstruction in Solidworks and its Applications in Industry
Abstract
Close range, image based photogrammetry and LIDAR laser scanning technique are commonly utilized methodologies to snap real objects.3D models of already existing model or parts can be reconstructed by laser scanning and photogrammetry. These 3D models can be useful in applications like quality inspection, reverse engineering. With these techniques, they have their merits and limitations. Though laser scanners have higher accuracy, they require higher initial investment. Close-range photogrammetry is known for its simplicity, versatility and effective detection of complex surfaces and 3D measurement of parts. But photogrammetry techniques can be initiated with comparatively much lower initial cost with acceptable accuracy. Currently, many industries are using photogrammetry for reverse engineering, quality inspection purposes. But, for photogrammetric object reconstruction, they are using different softwares. Industrial researchers are using commercial/open source codes for reconstruction and another stand-alone software for reverse engineering and mesh deviation analysis. So the problem statement here for this thesis is to integrate Photogrammetry, reverse engineering and deviation analysis to make one state-of-the-art workflow. The objectives of this thesis are as follows: 1. Comparative study between available source codes and identify suitable and stable code for integration; understand the photogrammetry methodology of that particular code. 2. To create a taskpane add-in using API for Integration of selected photogrammetry methodology and facilitate methodology with parameters. 3. To demonstrate the photogrammetric workflow followed by a reverse engineering case studies to showcase the potential of integration. 4. Parametric study for number of images vs accuracy. 5. Comparison of Scan results, photogrammetry results with actual CAD data. In this thesis, only open source code photogrammetry tools have been studied. Photogrammetric results obtained in the form of point cloud from these tools were compared to ideal point cloud from laser scanning tool. This was done using CloudCompare function. Once the best possible code for integrated is identified, its methodology was injected in SOLIDWORKS CAD tool. SOLIDWORKS tool provides functions like mesh cleanup(Pre-processing), reverse engineering and mesh-CAD deviation analysis. After integration has been done with API programming using CSharp, this workflow was tested with case studies for accuracy of results with actual 3D models. These CAD models were firstly converted to surface mesh and compared with mesh comparison function. The case studies presented in this report shows that scan mesh and photogrammetry mesh have relative accuracy of within 2 mm for a object of size ( 150 to 300 mm). The parametric study presented suggests that higher number of images increases accuracy of the reconstructed model. After comparison of CAD data, photogrammetry and scan results it can be inferred that photogrammetry can replace laser scanners if allowed tolerances are little higher. Hence this thesis, successfully presents reverse engineering function through photogrammetry in an integrated environment.
Degree
M.Sc.
Advisors
El-Mounayri, Purdue University.
Subject Area
Aerospace engineering|Computer science|Robotics|Transportation
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