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:
Jan. 18, 1983

Filed:

Apr. 22, 1981
Applicant:
Inventors:

John Bedford, Midlothian, GB;

Graham M Clarke, Edinburgh, GB;

Assignee:

Ferranti Limited, Cheadle, GB;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
250236 ; 358293 ;
Abstract

Correction for variations in scan period of optical image scanners includes measuring and storing the scan times at which optical events occur to cause image detector signals, detecting an optical marker near the end of the scan and the scan time of its detection, determining the difference between this scan time and a stored scan period, comprising the nominal scan time for marker detection, which difference represents the scan period error, dividing the difference by the stored scan period to provide a scan time unit error and multiplying each stored measured scan time by the unit error to provide a correction for each measured scan time, thereafter adding the correction to the stored measured scan time to give a corrected scan time.


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