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:
Feb. 03, 1998
Filed:
Oct. 21, 1996
Spencer D Luster, Toledo, OH (US);
Medar, Inc., Farmington Hills, MI (US);
Abstract
Spectral transmittance of a dye coating for optical data is determined off-line. Light source wavelength is then matched to the wavelengths at which the dye has the least transmission (i.e. maximum absorbance). The method and system of the present invention are provided for detecting local and global defects in the coating wherein the inspection is done at the maximum absorbance wavelengths to produce a maximum change in a transmitted light signal for a given change in physical thickness of the dye coating. Relative change in thickness is determined based on the change in the transmitted light signal through the dye coating. In order to complete detection and measurement of the transmittance changes, a pair of electronic signals are split from a camera signal wherein one of the electronic signals is filtered by a FIR filter to identify local changes in dye thickness against a globally varying background. In order to detect global variations in the dye thickness, the other electronic signal is processed by a simple thresholding circuit.