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. 18, 2000
Filed:
Apr. 01, 1998
David A Robinson, Northants, GB;
Medar, Inc., Farmington Hills, MI (US);
Abstract
A calibration algorithm is provided for calibrating a machine vision system including a color camera, a framegrabber and an illumination source wherein subsequently acquired images are processed on a pixel-by-pixel basis. After framegrabber offsets are measured to obtain initial or offset calibration data, the camera is pointed at a target monotone patch of known reflectance such as pure white and the camera outputs for red, green and blue are determined while observing the monotone patch to obtain spatial calibration data. The gain for each of the output channels of the color camera is automatically determined from the initial calibration data. Applying the three gain factors to a subsequent image on the pixel-by-pixel basis allows one to end up with a color-corrected image without incurring any time performance penalty. At any time during an inspection process, a small area of white reflectance can be observed. The resulting dynamic white calibration data is used to correct for any medium to long term temporal variation in imaging conditions.