Digital imaging method and apparatus for detection of document security marks

Assignee: Xerox Corp

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Filing: 2000-06-08

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Granted: —

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Expires: 2020-06-08

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Abstract

Abstract The present invention provides in one aspect a method of digitally processing images, comprising the steps of: potentially including in a printed document a security mark defined by a plurality of actual mark constituents, processing the image data to identify potential constituents, for each potential mark constituent represented by said digital image data, determining if said potential mark constituent, together with at least one other potential mark constituent represented by said digital data, defines a potential security mark, and, for each potential security mark represented in said digital image data, determining if said potential security mark represents an actual security mark present in said printed document. In a second aspect there is provided a digital image processing method for preventing unauthorized reproduction of a printed document. In a third aspect there is provided a method of processing digital image data representing a color printed document that includes a security mark.

Inventors

👤 Zhigang Fan

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 13:07

CPC Classifications

H; H04; H04N; H04N1/00; H04N1/00838; H04N1/0084; H04N1/00843; H04N1/00846; H04N1/00856; H04N1/00875

Claims Analysis

Total Claims: 3

Claim 1

Independent Claim 155 words

A method of digital image processing comprising: (a) for a printed document potentially including a security mark defined therein by a plurality of actual mark constituents each having a select color, size, and shape and having a select spatial arrangement relative to each other, scanning said document to obtain digital image data corresponding to said printed document, said digital image data defined in terms of a plurality of color input pixel values; (b) processing said digital image data to identify all portions representing potential constituents of a security mark; (c) for each potential mark constituent represented by said digital image data, determining if said potential mark constituent, together with at least one other potential mark constituent represented by said digital image data, defines a potential security mark; (d) for each potential security mark represented in said digital image data, determining if said potential security mark represents an actual security mark present in said printed document.

Claim 2

Dependent Claim 227 words

A digital image processing method for preventing unauthorized reproduction of a printed document including a security mark defined in terms of a plurality of actual mark constituents having a select color, select dimensions and arranged in a select pattern relative to each other, said method comprising: a. scanning said printed document to derive color digital data representing said printed document, said color digital data defined in terms of a plurality of pixels each having a color value; b. identifying all pixels of said color digital data having a color value representing a color at least approximating said select color of said plurality of actual mark constituents; c. constructing a binary map of said color digital data defined in terms of "on" and "off" pixels, said "on" pixels corresponding to said identified pixels of said color digital data having color values at least approximating said select color of said plurality of actual mark constituents; d. using said binary map, identifying potential mark constituents defined by said "on" pixels; e. using said binary map, identifying at least one neighborhood of plural potential mark constituents together defining a potential security mark; f. identifying said potential security mark as an actual security mark if said potential mark constituents thereof are uniform relative to each other; and g. preventing effective duplication of said printed document if an actual security mark is identified.

Claim 3

Independent Claim 203 words

A method of processing digital image data representing a color printed document that includes a security mark for purposes of identifying the security mark represented in said digital image data, said method comprising: a. processing said digital image data to identify all portions thereof defining a select color corresponding to the color of the security mark in said printed document; b. for each portion of said digital image data defining the select color, determining if the portion represents a potential constituent of a security mark in said printed document; c. for each potential security mark constituent identified in said digital image data, determining if said potential security mark constituent, together with at least one other potential security mark constituent, defines a potential security mark in said digital image data; d. comparing the potential security mark constituents defining each potential security mark to each other to determine if they are uniform in terms of color and size relative to each other; and e. identifying a potential security mark as a security mark represented in said digital image data if the potential security mark constituents of said potential security mark are sufficiently uniform in terms of the least color and size relative to each other.

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