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.

Date of Patent:
Aug. 25, 1992

Filed:

Aug. 02, 1990
Applicant:
Inventors:

John M Fitts, Santa Monica, CA (US);

Douglas M Linn, Walled Lake, MI (US);

Nilesh C Thakker, West Hills, CA (US);

Assignee:

General Motors Corporation, Detroit, MI (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
36455101 ; 364526 ; 356446 ;
Abstract

Video monitors sequentially displaying coarse bar patterns of various spatial frequencies are spaced two feet or more from a painted surface to be inspected. Video cameras, also spaced far from the surface, view the images reflected from the paint and a computer system analyzes the images by determining the modulation transfer function (MTF) of each reflecting surface. Surface curvature is compensated for by selecting the spatial frequencies in the sequence of patterns in accordance with the effect of the curvature on a reference pattern. The area under the MTF curve correlates to the distinctness of image of the surface and the area under the low spatial frequency portion of the curve correlates to orange peel.


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