Abstract
A position sensitive detector (PSD) has been used to determine the diameter of cylindrical pins based on the shift in a laser beam's centroid. The centroid of the light beam is defined here as the weighted average of position by the local intensity. A shift can be observed in the centroid of an otherwise axially symmetric light beam, which is partially obstructed. Additionally, the maximum shift in the centroid is a unique function of the obstructing cylinder diameter. Thus to determine the cylinder diameter, one only needs to detect this maximum shift as the cylinder is swept across the beam.
© 2007 Optical Society of America
Full Article | PDF ArticleMore Like This
W. Doyle St. John
Appl. Opt. 48(22) 4501-4505 (2009)
Jung-Ki Kim, Man-Suhk Kim, Jong Han Bae, Jin Hyuk Kwon, Hang-Boo Lee, and Soo-Hoa Jeong
Appl. Opt. 39(16) 2584-2591 (2000)
Jeffrey S. Morgan, D. C. Slater, John G. Timothy, and E. B. Jenkins
Appl. Opt. 28(6) 1178-1192 (1989)