The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 2004
Filed:
Jun. 23, 2003
Joseph C. Marron, Ann Arbor, MI (US);
LightGage, Inc., Bloomfield, NY (US);
Abstract
A system of frequency-scanning interferometry uses a computer system operating in accordance with a program for measuring distances or range, including measuring topographical information about test object surfaces. Interferometric data is detected using a single point detector or an array of such detectors and recorded (stored) in the computer system, and a series of measurements are taken over a range of illumination frequencies. The interferometric data varies in a sinusoidal manner with a change in illumination frequency at interference frequencies corresponding to particular measures of distance or range. A Fourier transform for locating peak interference frequencies is first limited in frequency space and second divided into stages to save processing time. A coarse spacing between Fourier frequency samples is used for a first approximation, and finer spacing between Fourier frequency samples are used in the vicinity of the first approximation to make a second more accurate approximation.