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:
Oct. 23, 1990
Filed:
Dec. 14, 1987
Applicant:
Inventors:
P A Crossley, Palo Alto, CA (US);
H Keith Nishihara, Los Altos, CA (US);
Assignee:
Schlumberger Technologies, Inc., San Jose, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06K / ;
U.S. Cl.
CPC ...
382-8 ; 382-1 ; 382 22 ; 382 42 ; 358107 ; 356373 ;
Abstract
A method and apparatus for measuring feature dimensions uses selective dark-field illumination to illuminate a target from a single direction at a low angle to the plane of the target. Opposing edges of the target elements are distinguished and captured in separate images. The images are filtered using a Gaussian convolution operator and a Laplacian operator. The signs of the filtered images are correlated at various offsets. The relative displacement of the images which produces the maxium correlation value is used to calculate the average dimension of the target elements.