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:
Jan. 03, 1995
Filed:
May. 14, 1993
Adalbert Hanssen, Konigsbronn, DE;
Albrecht Hof, Aalen, DE;
Carl-Zeiss-Stiftung, Heidenheim, DE;
Abstract
In a process and apparatus for measuring object topographies by means of projected fringe patterns, to enlarge the region of certainty, different periodicities are evaluated. Calibration of the measurement apparatus is carried out in at least two parallel planes, situated in the forward and in the rearward regions of the measurement volume. Corrected phase values are first calculated from the phase measurement values of the measurement object. By combination of the phase measurement values relating to the pattern of long periodicity and of the pattern of short periodicity, the fringe order of the phase values relating to short periodicity is calculated. By interpolation of the correction values between the two planes in which the reference measurements were carried out, the measurement process and a corresponding measurment apparatus provide highly accurate measurement values, with simultaneously reduced requirements on the accuracy of mechanical and/or optical adjustment.