Structured Light Illumination Technique (SLIT)

(Last update July 28, 2003)

Implemented Fall of 1995

Laurence Hassebrook and Raymond Daley

Department of Electrical Engineering at the University of Kentucky

in collaboration with

Richard Muse and Terry McIlvain

Center for Robotic and Manufacturing Systems

Figure 1: The Structured Light Illumination Technique (SLIT) machine represents our first machine based on the classical single light stripe technique. We constructed it with a $13,000 grant in about 14 weeks. It was one of those rare projects where everything worked right, fit well together, etc.. Its measurement accuracy for a flat surface was a standard deviation of 1.56 microns or 0.0000625 inches. The surface under measurement was a black foam "rubber" surface which was machined to be flat. One of the problems with measuring such a surface was that it had a mixture of textures. The basic surface texture was corrupted by large pockets or "crater" like shapes. The Central Limit Theorem was limited in this case since the mixture of measurements led to high standard deviations. We developed some vary sophisticated nonlinear filtering techniques to separate the two surface textures which allowed for the high accuracy. The machine was also made more robust by using 3 levels of measurement combined into an AI like state process.