The Robotics Institute

Carnegie Mellon Robotics Institute

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Abstract

The measurement of shape is a basic object inspection task. We use a noncontact method to determine shape called photometric stereo. The method uses three light sources which sequentially illuminate the object under inspection and a video camera for taking intensity images of the object. A significant problem with using photometric stereo is determining where to place the three light sources and the video camera. In order to solve this problem, we have developed an illumination planner that determines how to position the three light sources and the video camera around the object. The planner determines how to position light sources around an object an accurate measurement. We predict the uncertainty in our measurements due to sensor noise by performing a statistical simulation in our planner. This gives us the capability to determine when a measured shape differs in a statistically significant way from what we expect. From a high level, our planner has three major inputs: the CAD model of the object to be inspected, a noise model for our sensor, and a reflectance model for the object to be inspected. We have experimentally verified that the plans generated by the planner are valid and accurate.

Notes

Sponsor: ARPA, Dept. of Army

Grant ID: DAAH04-94-G-0006

Number of pages: 57

Text Reference

Fredric Solomon and Katsushi Ikeuchi, "An Illumination Planner for Convex and Concave Lambertian Polyhedral Objects," tech. report CMU-RI-TR-95-04, Robotics Institute, Carnegie Mellon University, March, 1995

BibTeX Reference

@techreport{Ikeuchi_1995_363,
   author = " Fredric Solomon and Katsushi Ikeuchi",
   title = "An Illumination Planner for Convex and Concave Lambertian Polyhedral Objects",
   booktitle = "",
   institution = "Robotics Institute",
   month = "March",
   year = "1995",
   number= "CMU-RI-TR-95-04",
   address= "Pittsburgh, PA",
}

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