James Kuffner  

Recovering 3D Geometry using a Robot Arm and a Laser Scanner
James Kuffner, Jr.

Spring 1994

Project Overview : The goal of this project is to reconstruct the 3D geometry of a static object.  Scanning devices that use rotating or translating platforms can only scan relatively small movable objects, and typically must make multiple scans and combine the data as a post-process.   Mounting the scanner on a controlled robot provides a means for scanning larger objects in a single pass.  In addition, objects which cannot be moved (such as building facades) can also be scanned.

Concept : Given a robot with a device that emits a plane of laser light, the idea is to sweep the plane of light across the surface of the object and view the profile of the object contour using an off-axis CCD camera mounted near the laser. The resulting camera images can be used to compute the 3D coordinates of points on the object surface via triangulation.

scannerClick here to view a diagram.

Final Report: Download a gzipped postscript file (15 pages = 139K).

Software: Four original C programs constituted the bulk of the project effort.

bulletA program to correct for camera image distortion.
bulletA program to interpret the camera images and output 3D coordinates of the object surface.
bulletA program to take a set of 3D coordinates and output a triangular mesh corresponding to a surface that fits the data points.
bulletFinally, a visualization program written for the SGI that allows a user to interactively view the triangular mesh of the original scanned object.

Work Schedule : The project was completed in approximately five weeks. Three main work phases were involved: [Equipment setup, testing, and data collection (1.5 weeks), Data interpretation software (2.5 weeks), Mesh visualization software (1 week)].

Other References: Standard calibration algorithms presented in class and in the textbook were used, as well as notes on triangulation and mesh-generation from 3D data points (specifically: Drushel, R F. Survey of methods for 3-dimensional reconstruction" comp.graphics.visualization: Usenet, 1993)

1997 - 2009 © James Kuffner, Jr.