Department of Electrical and Systems Engineering

1
ABSTRACT Three dimensional (3D)
image acquisition systems are becoming more
valuable in today's digital environment.
Contemporary 3D acquisition systems allow for the
construction of accurate models of 3D objects.
The reduction in price and the ubiquity of
personal computers creates the opportunity for
new virtual reality applications. One growing
application for such a system is the modeling of
historical artifacts and excavation sites.
Archaeologists spend large amounts of time
documenting and diagramming uncovered artifacts
3D acquisition systems can help to insure that
more time is spent on the actual excavation and
analysis process of these sites. For such an
application, a 3D modeling system would require
medium to high accuracy reconstruction, ease of
use, affordability, and operational safety for
both the operator and the scanned artifact. With
these specifications in mind, we chose to develop
a sensor based 3D modeling structured light
system. One major advantage of such a system is
its low cost. A laser, charge coupled device
(CCD) camera, and motor are all
commercial-off-the-shelf (COTS) products, which
makes this system cheaper than other systems that
implement more advanced tools. Our system
acquires data from a 3D object by panning a laser
across an object and simultaneously capturing
images using a digital color camera. From the
disparity between the laser profile over the
object and the laser's expected projection onto
the reference plane, depth values will be
calculated and then analyzed to create a 3D
model.
3D Sensor Based Structured Light
SYSTEM OVERVIEW
SYSTEM COMPONENTS
A class IIIb laser with a single slit is used to
project a laser line onto a 3D scene.  The laser
is mounted on top of a rotary turntable that is
used to rotate the laser across an object with a
resolution of ten lines per 3 degrees and 0.1
degree accuracy.  A CCD camera is used to
capture images of the distorted laser line as it
pans completely across the object. Once all the
images are captured, they are run through a laser
line detection module to extract the position in
pixels of the distorted laser line. From the
distortion in the laser line and the camera/laser
calibration matrices a depth map of the scanned
scene is constructed.  The depth map is finally
refined into a 3D model. An overall system
flowchart can be seen below.

• Hardware flowchart

• Graphical User Interface for Image Acquisition
  System

GROUP 2 AUTHORS Oyebode Fajobi ESE 05 Kevin
Quach ESE 05 Imo Udom ESE 05 ADVISOR Kostas
Daniilidis Associate Professor Computer
Information Science DEMO TIMES Thursday, April
21st, 2005 1030 AM - 1200 PM 100 -130 PM

• Graphical User Interface for Turntable

Department of Electrical and Systems Engineering