Method for controlling the quality of printed documents based on pattern matching

US8571327B2 · kind B2 · utility

Assignee

• KBA-NOTASYS SA · CH

Inventors

• Jorn Sacher · Hiddenhausen, DE
• Bernd Stober · Rheda-Wiedenbrück, DE
• Harald Heinrich Willeke · Paderborn, DE
• Volker Lohweg · Bielefeld, DE
• Thomas Türke · Lonay, CH

Key dates

• Filing date: Sep 3, 2007
• Grant date: Oct 29, 2013
• Expiry date: May 23, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G07D7/0032
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A method for controlling the quality of printed documents, such as banknotes, in which only part of the surface of the printed documents is available for inspection, comprising the steps of (i) storing a reference image; (ii) acquiring a sample image of a sample printed document to be controlled, which sample image covers only a limited portion of the sample printed document; (iii) selecting a search pattern within the acquired sample image; (iv) searching the reference image for a match with the selected search pattern, (v) determining control parameters linked to the position of the search pattern within said sample image and within said reference image, (vi) comparing the control parameters linked to the position of the search pattern within the sample image with the control parameters linked to the position of the search pattern within the reference image; and (vii) based on the results of the comparison of the control parameters, accepting or rejecting the sample printed document.