Methods for stimulating the effect of distortion on representations of markers and methods for analyzing representations of markers using simulations of distortion

Abstract

A method of simulating the effect of distortion on a representation of a marker, such as a fingerprint is provided. The method is useful for generating data for use in various processes concerned with fingerprints and particularly avoids the need to manually generate and collect such data. The method includes obtaining a plurality of representations from an individual, the representations being subject to different distortions relative to one another. A function, such as a thin plate spline function, is then used to describe the effects of the different distortions on the plurality of representations obtained. This generic model of the effects of distortion can then be used to generate distortions for a further representation from an individual, preferably another individual. The simulated distorted representations can be used in a variety of ways.

1 .- 18 . (canceled) 
     
     
         19 . A method of simulating the effect of distortion on a representation of a marker, the method comprising:
 a) obtaining a plurality of representations from an individual by physically sampling that individual, the representations being subject to different distortions relative to one another;   b) describing the effect of the different distortions on a pair of representations from amongst the plurality of representations using a function;   c) repeating steps a) and b) for a plurality of individuals to provide a plurality of functions;   d) obtaining a composite distorting function, the composite distorting function being based on a combination of two or more of the plurality of functions;   e) taking a further representation from a further individual by physically sampling that further individual, said further individual being a different individual from the individual of step a) and any of the individuals of step c) and applying the composite distorting function to that further representation to generate one or more simulated distorted representations using a computer implemented method; and   f) repeating step e) for another further representation.   
     
     
         20 . A method according to  claim 19  in which the function is or includes a non-linear function. 
     
     
         21 . A method according to  claim 20  in which the function is a non-linear transformation. 
     
     
         22 . A method according to  claim 19  in which the function is or includes one or more matrices. 
     
     
         23 . A method according to  claim 19  in which the representation includes one or more minutiae, each of the one or more minutiae having a position and in which the comparison considers the position of one or more minutiae in each of the representations. 
     
     
         24 . A method according to  claim 19  in which the function is defined, at least in part, by a thin plate spline approach. 
     
     
         25 . A method according to  claim 19  in which the plurality of representations are obtained from the individual under controlled conditions. 
     
     
         26 . A method according to  claim 25  in which the representations are obtained from a finger and in which the controlled conditions are controlled in terms of the finger used and/or substrate used and/or pressure used and/or extent of distortion used. 
     
     
         27 . A method according to  claim 19  in which one or more repeats of each representation are obtained. 
     
     
         28 . A method according to  claim 19  in which two or more of the functions are combined to give the distorting function in the form of a composite function. 
     
     
         29 . A method according to  claim 19  in which two or more of the functions are combined to give a general description of distortion. 
     
     
         30 . A method according to  claim 28  in which the composite function is used to generate one or more simulated distorted representations from the further representation. 
     
     
         31 . A method according to  claim 19  in which the further representation to which the function is applied is an undistorted representation. 
     
     
         32 . A method according to  claim 19  in which a plurality of simulated distorted representations are obtained from each representation. 
     
     
         33 . A method according to  claim 19  in which the distorting function is used to generate one or more simulated distorted representations for a plurality of other individuals, with the distorting function used for each of the other individuals being the same. 
     
     
         34 . A method according to  claim 19  in which the simulated distorted representations are supplied to a data set. 
     
     
         35 . A method according to  claim 34  in which the data set is used in a comparison method in which a representation being compared is considered against within finger variability and/or between finger variability. 
     
     
         36 . A method according to  claim 34  in which the data set is used to form a probability distribution. 
     
     
         37 . A method according to  claim 36  in which there is a distance between different representations of the marker, wherein the marker is the same in the different representations and the probability distribution relates to the distance between different representations of the same marker and/or in which there is a distance between different representations of different markers and the probability distribution relates to the distance between different representations of different markers. 
     
     
         38 . A method according to  claim 19  in which the method is repeated for one or more different types and/or directions of distortion. 
     
     
         39 . A method of simulating the effect of distortion on a representation of a marker, the method including:
 a) obtaining a plurality of representations from an individual by physically sampling that individual, the representations being subject to different distortions relative to one another;   b) describing the effect of the different distortions on a pair of representations from amongst the plurality of representations using a function;   c) repeating steps a) and b) for a plurality of individuals to provide a plurality of functions;   d) taking two or more of the functions and combining them to give a composite function;   e) taking a further representation from a further individual by physically sampling that further individual and applying the distorting function to that further representation to generate one or more simulated distorted representations using a computer implemented method, the distorting function being the composite function.   
     
     
         40 . A method of analysing a representation of a marker, the method including
 1) obtaining a representation of the marker from a location;   2) processing the representation by applying a composite function to the representation to generate one or more revised representations using a computer implemented method, the composite function being obtained by a method including:   a) obtaining a plurality of representations from an individual by physically sampling that individual, the representations being subject to different distortions relative to one another;   b) describing the effect of the different distortions on a pair of representations from amongst the plurality of representations using a function;   c) repeating steps a) and b) for a plurality of individuals to provide a plurality of functions; and   d) taking two or more of the functions of step c) and combining them to give the composite function;   the method of analysis further including:   3) comparing the one or more revised representations with one or more existing representations to analyse the representation of the marker for a match with the one or more existing representations and/or a lack of a match with the one or more existing representations.   
     
     
         41 . A method of analysing a representation of a marker, the method including
 1) obtaining a representation of the marker from a location;   2) processing the representation by applying a composite function to the representation to generate one or more revised representations, the composite function being obtained by a method including:   a) obtaining a plurality of representations from an individual by physically sampling that individual, the representations being subject to different distortions relative to one another;   b) describing the effect of the different distortions on a pair of representations from amongst the plurality of representations using a function; and   c) repeating steps a) and b) for a plurality of individuals to provide a plurality of functions, the composite function being based on two or more the plurality of functions;   the method of analysis further including:   3) comparing the one or more revised representations with one or more existing representations to analyse the representation of the marker for a match with the one or more existing representations and/or a lack of a match with the one or more existing representations.   
     
     
         42 . A method according to  claim 41  in which the comparing considers a position of one or more minutiae in each of the revised representations and the one or more existing representation and/or considers a position of one or more points on one or more ridges in each of the revised representations and the one or more existing representation. 
     
     
         43 . A method according to  claim 41  in which the function is defined, at least in part, by a thin plate spline approach. 
     
     
         44 . A method according to  claim 41  in which two or more of the functions are combined to give a general description of distortion. 
     
     
         45 . A method according to  claim 41  in which the further representation to which the composite function is applied is an undistorted representation. 
     
     
         46 . A method according to  claim 41  in which a plurality of revised representations are obtained from each representation. 
     
     
         47 . A method according to  claim 41  in which the composite function is used to generate one or more revised representations for a plurality of other individuals, with the composite function used for each of the other individuals being the same. 
     
     
         48 . A method according to  claim 19  in which the representation includes one or more points on one or more ridges, each of the one or more points having a position and in which the comparison considers the position of one or more points on one or more ridges. 
     
     
         49 . A method according to  claim 23  in which the representation also includes one or more points on one or more ridges, each of the one or more points having a position and in which the comparison considers the position of one or more points on one or more ridges.