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:
Dec. 10, 1996
Filed:
Feb. 08, 1993
Richard L Rylander, Stillwater, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A screen system used in the electro-optical reproduction of half-tone pictures in multicolor prints are generated by an algorithm which simulates a continuous tone image containing a range of gray shades from black to white or a color separation. The 'threshold equation' is the key of the invention as it calculates a threshold gray value that is compared to the desired local image value to determine whether that particular point should be 'on' or 'off'. Which points (spots) are 'on' and which are 'off' is determined by the function that assigns a 'threshold' value (the shade at which a pixel changes from 'off' to 'on') based on a pixels 'x' and 'y' coordinates. The generated screen comprises columns and rows of halftone dot centers in which there is equal spacing in row to row, column to column, and column to rows relationships, but the columns are not geometrically orthogonal (perpendicular) to the rows.