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. 09, 1982
Filed:
Aug. 01, 1979
Ruediger Sommer, Raisdorf, DE;
Hermann Wischer, Kiel, DE;
Dr.-Ing. Rudolf Hell GmbH, Kiel, DE;
Abstract
The invention relates to facsimile reproduction and particularly to a method for converting a video signal obtained by scanning an original dot by dot and line by line, into a bilevel black/white signal. In the black/white recording of colored originals in which both the background and the information can be white, black, grey or colored, grey/black transitions coming from 'white' and grey/white transitions coming from 'black' are frequently not evaluated correctly by the dynamic threshold so that information is lost in the copy. In order that these types of transitions are also detected, it is suggested to eliminate the DC component of the video signal and to compare the video signal modified in this way with a second dynamic threshold signal derived from it. The comparison signal is logically linked to the customary black/white signal in such a manner that the black/white signal is flipped to 'white' at a grey/black transition and to 'black' at a grey/white transition in each case for a specified time interval. In this manner, for example between a colored area in the original recorded as 'black' and a black letter in this area, a white boundary line is created which makes the front contour of the letter visible. Similarly, between a colored area in the original reproduced as 'white' and the white edge of the original copy a black boundary line is generated which makes the contours of the colored area in the original clearly recognizable.