Method of inserting hidden data into digital archives comprising polygons and detection methods
First Claim
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1. ) a combined process of insertion of a watermark and its corresponding detection process in a digital file composed of polygonals (as is the case of a cartographic map, or an architect'"'"'s plan) or similar items, in which the insertion process is characterised by comprising the following steps:
- a) Defining the length N of the watermark b) Defining the arbitrary key to be used as the identifier (different for each instance of the map) c) Generating W, a set of N real numbers belonging to (0,1), using the key and any pseudo random number generator routine d) Loading the (X,Y) corrdinates of all the polygonals existing of the map e) Selecting all polygonals in the map with a minimum number of vertices, and ignore the others f) For each one;
g) Calculating its length L h) Calculating the curvilinear coordinates of all its vertices i) For each element W(i) of W j) Calculating the (X,Y) coordinates of a point with curvilinear coordinates W(i)*L by linear interpolation of those of the vertices k) Adding a new vertex with such coordinates (X,Y) to the map l) Next W(i) m) Next polygonal and the corresponding detection process is characterized by comprising the following steps;
a) Otaining information about N, the random number generator, and the set of known keys used b) Loading the (X,Y) coordinates of the polygonals existing in the map c) Selecting all polygonals in the map with a minimum number of vertices, and ignoring the others d) For each one;
e) Calculating the curvilinear coordinates of all its vertices f) For each key;
g) Setting an integer counter to 0 h) Generating W as described before i) For each element W(i) of W j) Check if within a tolerance there exist a vertex of curvilinear coordinate W(i)*L k) If so, incrementing by one the counter, otherwise continue l) Next W(i) m) Quitting if the quotient of the counter and N is larger than a preset threshold;
the current key denotes the watermark found n) Next key o) Next polygonal
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Abstract
The invention relates to a method of inserting a watermark into a digital archieve comprising polygons (e.g. a map) and of detecting the absence or presence of said watermark. The watermark does not alter the digital map in any noticeable manner and it cannot be modified by common isometric transformation.
36 Citations
7 Claims
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1. ) a combined process of insertion of a watermark and its corresponding detection process in a digital file composed of polygonals (as is the case of a cartographic map, or an architect'"'"'s plan) or similar items, in which the insertion process is characterised by comprising the following steps:
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a) Defining the length N of the watermark b) Defining the arbitrary key to be used as the identifier (different for each instance of the map) c) Generating W, a set of N real numbers belonging to (0,1), using the key and any pseudo random number generator routine d) Loading the (X,Y) corrdinates of all the polygonals existing of the map e) Selecting all polygonals in the map with a minimum number of vertices, and ignore the others f) For each one;
g) Calculating its length L h) Calculating the curvilinear coordinates of all its vertices i) For each element W(i) of W j) Calculating the (X,Y) coordinates of a point with curvilinear coordinates W(i)*L by linear interpolation of those of the vertices k) Adding a new vertex with such coordinates (X,Y) to the map l) Next W(i) m) Next polygonal and the corresponding detection process is characterized by comprising the following steps;
a) Otaining information about N, the random number generator, and the set of known keys used b) Loading the (X,Y) coordinates of the polygonals existing in the map c) Selecting all polygonals in the map with a minimum number of vertices, and ignoring the others d) For each one;
e) Calculating the curvilinear coordinates of all its vertices f) For each key;
g) Setting an integer counter to 0 h) Generating W as described before i) For each element W(i) of W j) Check if within a tolerance there exist a vertex of curvilinear coordinate W(i)*L k) If so, incrementing by one the counter, otherwise continue l) Next W(i) m) Quitting if the quotient of the counter and N is larger than a preset threshold;
the current key denotes the watermark foundn) Next key o) Next polygonal - View Dependent Claims (2, 3, 4, 5, 6)
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7. ) The combined process characterised in that it does not depend or rely on the format, number of bits, etc. in which the digital file is stored inside a computer system, but only on the geometric information itself represented by it.
Specification
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Current AssigneeCarlos Manuel Lopez Vazquez
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Original AssigneeCarlos Manuel Lopez Vazquez
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InventorsLopez Vazquez, Carlos Manuel
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Application NumberUS10/454,318Publication NumberTime in Patent OfficeDaysField of SearchUS Class Current713/176CPC Class CodesG06T 1/0064 Geometric transfor invarian...G06T 2201/0051 Embedding of the watermark ...H04N 1/32149 Methods relating to embeddi...H04N 1/32277 Compression
