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. 10, 1981
Filed:
Apr. 11, 1979
Gerhard Haupt, Konstanz, DE;
Abstract
Patterns on a recording medium are scanned, with reflected light from a light source, and interference factors occurring from fluctuating diffused reflectance of the recording medium and the changing distance of the light source from the scanning field are overcome through the regulation of the light source in response to the light received by the scanner. With a control loop for the light source undesired information in the image signal is eliminated by regulating the illumination intensity. In the scanning device, a sensor converts the light reflected from the scanning field into a plurality of individual analog signals. A sum signal is formed from the individual signals and is provided, delayed, as a measurable variable and is compared with a predetermined reference value in a comparator. The output signal of the comparator controls a regulating unit in the electric circuit of the light source. Inasmuch as the aforementioned interference factors are particularly aggravating when different recording media are scanned and the recording media are not automatically transported during scanning, the device is of particular advantage when employed in manually-guided, hand-held reading devices.