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8/9/2019 29 CapstonePoster 3DScanning Final
1/1
3D Surface Scanning and Reconstruction Via Structured Light Methods
Click: See the World in 3D
Abstract
Background
ResultsMethods
Max Larner, Nabjot Sandhu, Mark Ortiz, Kathleen Chung, Chai Lor,Changqing LiSchool of Engineering, University of California, Merced
Acknowledgements
References
Conclusion
The code used in the programming was originated at BrownUniversity and can be found at the following address:
http://mesh.brown.edu/dlanman/scan3d.
Guidance was provided by Dr. Changquing Li and Chai Lor.
Additional thanks to Matthew Carfano for the company logo.
1.http://mesh.brown.edu/3DPGP-2009/index.html2. http://code.google.com/p/structured-
light/downloads/detail?name=ThreePhase-1-win.zip&can=2&q=
3. Zhang S, Huang PS; Novel method for structured light system
calibration. Opt. Eng. 0001;45(8):083601-083601-8.
Coding:
An open source C++ code from Brown Universitywas used[1]. Modifications to the code were made
to make it specific and compatible for the specific
equipment used to carry out the experiment.
Visual Studio was used to run and modify the
code, then Meshlab, which is also an open source
program was used for the surface reconstruction
from the point clouds.
1. Implement code for camera and projector
calibrations[1, derived from 3].
2. Implement structured light scanner.
3. Save images and call them into Meshlab.
4. Use Meshlab to reconstruct surfaces from point
clouds and reconstruct the scanned image.
Physical Setup:
The setup is done on an optical board and
encased by a dark box made out of painted acrylic.
The setup allows for the camera to have a
horizontal view of the specimen. The camera and
pico projector(AAXA P4X) is mounted a certain
distance away from the platform on which the
specimen is placed.
Figure 2. Setup on the optical board
Scanning and reconstruction of an image are key
for the creation of a 3D model. 3D models can becreated through the use of structured light
methods. This was done by using a structured light
method coded in C++. The camera-projector pair
must be calibrated and the object is then scanned
with grey codes. It was concluded that an accurate
3D model can be created with high precision if a
proper calibration technique is used.
3D images can be used in research to accurately
create models of specimens. Current widely used
camera systems capture images in 2D, but to get
accurate measurements and models of the
specimens they need to be viewed as 3D images.
A solution to this problem is the use of structured
light to take scans that can be interpreted as 3D
images. These scans use a series horizontal and
vertical grey patterns. Scans of an object can be
taken using programming languages such as C++.The code for the calibrations and scanning was
found as an open source f ile from Brown
University[1]. The code used various C++ libraries
including OpenCV. The complication with the file
was that it was not compatible with current
operating systems, so modifications were
necessary to run the code. These scans produce
horizontal and vertical interpretations of the
specimen or object being scanned. The individual
interpretations are then decoded to create a depth
map. The depth map is then used to construct a
point cloud which can then be saved as .wrl files.
The models can be opened with a program such
as Meshlab which is used to process and edit 3Dpoint clouds. In Meshlab these individual points
are reconstructed into a surface which can be
meshed into a well defined 3D image.
Location
Actual
(mm)
Imaged
(mm) %Error
Top to First Ring 68 68.32 0.470588Top to Second Ring 74 73.54 -0.62162
Across Top 58 55.57 -4.18966
Inner Rectangle 31 30.45 -1.77419
Between Rings 7 7.15 2.142857
Figure 4. Untouched scan image
Figure 5. Cleaned scan image, all
extraneous points removed
Figure 6. Reconstructed surface
image with residual normals
Figure 7. Complete meshed
and surfaced object surface
Figure 1.Calibration board
used for camera and
projector pair
Results from the scans indicate that calibration
plays a large role in obtaining an accurate scan.When calibration is properly preformed, resolution
within 5% (