Title of Invention

"METHOD AND SYSTEM FOR DOCUMENT AUTHENTICATION"

Abstract

A method and system for document authentication to distinguish between an original document and subsequently reproduced copies of the original document by comparing the image of original document with that of the presented copy. A security mark, embedded in the document image, is used to derive and conclude whether the presented document is original or counterfeit. The security parameters extracted from the security mark on the document. These parameters are used for authenticating documents.

Full Text

Field of the Invention The instant invention relates to method and system for document authentication. Background of the Invention The need for distinguishing between original and counterfeit copies of a document is felt everywhere in day-to-day life. The result of forged documents, which closely resemble original document, gaining entry as original documents, amounts to huge losses for organizations as well as individuals. A common example is forgery of bank checks. These days sophisticated, high-end printers and scanners are able to reproduce replicas of bank checks that appear exactly as the original check. Every year, millions of dollars are fleeced using fraud checks, which precisely resemble the original checks. This results in cheating of money on unsuspecting legal account holders of the bank. Another example could be of a lottery ticket, which again can be reproduced with the help of modern day scanning, image capturing, and printing apparatus to closely resemble the original ticket. This loophole again can result in substantial losses for the lottery company. In yet another example, an identity card or passport could be forged to let an impostor gain entry to restricted buildings, sites, office, and thus making these sensitive sites prone to malicious intents of the impostor. Such things are possible simply because the forged documents establishing his/her identity are impervious to existing methods of fraud detection by being too good and too close in quality to seem like the original documents. Similarly, in every conceivable walk of life, forging of documents is present and results in loss to holder of rightful owner of the original copy of the document. Various methods have been suggested to recognize, catch and discard counterfeit documents. For bank notes, special paper, special ink, watermarks, and a specific process called intaglio printing are used. Some other methods to protect the authenticity of the original documents involved lacing the paper substrate with specialized coating, which is not impervious to various phenomenon, physical or otherwise, involved during the photocopying, scanning or printing process. This physical phenomenon could be heat produced, optical distortions, etc. during photocopying, scanning and printing. To take advantage of heat produced during operation of the aforementioned devices, original document is covered with a chemical coating responsive and reactionary towards heat, resulting in distortion of image printed on the document. To take advantage of optical distortions involved in operation of aforementioned devices, original document is laminated with a surface making the document react as diffraction surface. This document, when tried to be forged, is illuminated by light source in the photocopier or scanning device, produces irregular garbled patterns, which makes the reproduced copy of the original document distinct from the original copy. US6603568 describes a security system where a graphic field is added to a ticket (the document to be secured). The graphic field is a simple plurality of detectable half tone gray steps, a continuum of spots that slowly vary from small white backgrounds with large black spots to small black spots on a white background. This is a direct usage of Point Spread function. The changes due to the Print-Scan cycle are visibly apparent which is disadvantageous in the application. Hence there is a need for a system where the changes due to the Print-Scan cycle will not be so apparent to the user. The main disadvantages with all these methods are that they require substantial costs, manual intervention, and often, specific solution. The instant invention provides a low-cost, fully automatic, and all-inclusive method and system applicable to all types of document. It is a generic-yet-robust solution to address forgery of documents. Object and Summary of the Invention The principle object of the instant invention is to provide a method and system for checking the authenticity of the documents. A further object of the instant invention is to reduce the cost for identification of forged documents. Another object of the present invention is to provide a mechanism for verifying the authenticity of the presented documents, which may be grayscale or colored. Yet another object of the present invention is to provide a method and system for user identification using the security mark. A method for document authentication comprising the steps of: - Collect information from user and generate a security mark with this information embedded in it - creating an authentic document with said security mark; - obtaining multiple images of said authentic document with said security mark; - extracting a set of parameters from said security mark on each of said multiple images; - setting a threshold based on each said set of parameters from said security mark on each of said multiple image; - presenting said authentic document to a verification device; - extracting said set of parameters from said security mark on said authentic document; - obtaining set of values based on said set of parameters for said security mark on the authentic document; - comparing said set of values to multiple thresholds obtained by said setting of thresholds; and - authenticating a document subject to results of said comparing. A system for document authentication comprising: - a document creation device receiving an original document for creating an authentic document with a security mark; - a first image acquisition device receiving said authentic document for obtaining multiple images of said authentic document; - an image processing device for extracting a set parameters from said security mark on each of said multiple images and authentic document, and setting multiple thresholds and set of values; and - a verification device for authenticating said authentic document subject to comparison of said multiple thresholds and set of values. Brief Description for the Accompanying Drawings The invention will now be described with reference to the accompanying drawings. Figure 1 illustrates the flowchart for the operation of method for obtaining an authentic document. Figure 2 illustrates the flowchart for the training operation in the preferred embodiment. Figure 3 illustrates the flowchart for the operation of method for establishing authenticity of the document in the preferred embodiment. Detailed Description of the Invention The present invention relates to correctly deciding whether the presented document is an original one or counterfeit. The original printed copy of the document cannot be reproduced exactly, no matter, howsoever sophisticated scanning, printing video device, digital or analog, are employed to produce exact replica of the original document. The present invention can identify between the original and reproduced image. Figure 1 illustrates the flowchart for the operation of method for obtaining an authentic document. The initial document maybe taken as the original document or the digital image of the document taken using a scanner (1.1). The invention embeds a specially devised pattern, hereafter referred to as security mark, in the document to produce an authentic document. This security mark contains various sub-patterns; each designed to deal with different aspects of counterfeiting a document. The security mark is embedded in the original document using a printer with a processor for generating a security mark (1.2 and 1.3). In another embodiment, a digital copy is embedded with a security mark (1.2) and the image with security mark is printed out using a simple printer to form an authentic document (1.3). A second digital copy of the authentic document is acquired using various image acquisition devices like a scanner or a digital camera (1.4). This image is called an authentic image and is used as a reference image for the subsequent authentication process. Figure 2 illustrates the flowchart for the training operation in the preferred embodiment. Before starting the verification process of any document, training is conducted to compute a set of threshold values corresponding to 18 parameters. Several authentic images are taken of the authentic document using different image acquisition devices. Several fake documents are generated using various means including tampering of the authentic image. Fake images of such fake documents are acquired using different image acquisition devices. Thus multiple images are acquired to form a comprehensive set of test data for different image acquisition devices for both fake and authentic documents. (2.2) Various parameters like brightness, contrast, shapes of embedded geometrical, linearity, grayscales, variogram for texture detection, special frequency spectra, colorimeters, sharpness and blurriness for said security mark are extracted from each digital image, both fake and authentic, and the parameters are stored for a set of original and fake documents. (2.3 and 2.4) These parameter values for each digital image are used for determining a threshold value corresponding to each parameter. (2.5) The weight for each parameter is also determined using this set of parameters extracted from various images as the input for a statistical analysis. Statistical analysis is performed for test data obtained for both fake and authentic documents to obtain threshold values. The weights may also be obtained using the test data as training input for a neural network. (2.5) Figure 3 illustrates the flowchart for the operation of method for establishing authenticity of the document in the preferred embodiment. Now, the document to be verified is presented to the authentication device. (3.2) The security mark located and extracted and the parameters are calculated. (3.3 and 3.4) These parameters are compared with the corresponding threshold values computed earlier. (3.5) The result of each comparison is given different weight calculated previously (3.6), and a decision value calculated by the sum of these weighted values (3.7). This decision value defines the authenticity of the document. Once an image is reproduced by photocopying, scanning-printing or other optical means, there are certain changes introduced in these sub-patterns in the security mark. These changes can be captured by the algorithm used in the present invention. The method determines various factors to distinguish between original and fake images. In one embodiment, measuring blurriness introduced by calculating the Modular Transfer Function (MTF), which measures the spatial frequency present in the images. The modulation transfer reflects how well the contrast has been maintained in the image. The method also determines the shift in the image due to scanning and generates histogram patterns of gray levels to identify the forged copies. Similarly, the method checks for a number of other parameters to verify the authenticity of the documents. The method leverages the inherent advantage in determining a counterfeit document - one needs to detect all parameters in the Security Mark in two copies of the document image. The presented document can be marked as counterfeit based on the weighted comparison values of all parameters with their thresholds. The basic premise of the solution is that an image loses its quality when it is scanned or photocopied. This happens even if the image is scanned at high resolution and subsequently printed too at a high resolution. The method detects the deterioration in quality of the image by comparing the image with the original image. The security mark consists of a plurality of grayscale regions or sub-patterns. Factors are estimated from these regions, which are combined to take decision about the authenticity of the document. The sub-patterns can be rearranged according to the size and layout of the document. In the preferred embodiment, a set of four 'circular patterns' is treated as the registration marks to estimate any geometrical or affine transformations present in the security mark. Process of printing and scanning introduces geometrical transformations, like skew, shear, scaling, translation etc. Using the registration marks, the security mark extracted from the presented copy is mapped to the coordinate space of the original security mark to correct these modifications The security mark has linear and spherical distribution of gray scales to estimate the overall brightness and contrast change. These patterns are used as a normalization step before the factors mentioned below are estimated. A random spread of different gray levels, randomly is used to estimate brightness and contrast of the image. Some gray scale patterns represent certain three- dimensional geometrical shapes. These shapes can be reconstructed when the pattern is sampled at a particular dpi and 24-bit gray scale. The method steers the scanned data to these dpi and gray scales so the true dimensions of these geometrical shapes can be determined. We expect a redistribution of gray scales and spatial frequencies in a print-scan-cycle, which should be indicated in the change in the dimension of these geometrical shape(s). Some regions of the security mark are optimized in spatial frequency domain, to suffer the losses in a print-scan-cycle. These patterns are filtered at certain experimentally predetermined frequencies. The solutions proposed so far involved substantial manual intervention in the verification of the documents. Only very few proposed solutions are automated and even those are not fully automated as they involve some manual intervention. Our solution is unique that it is fully automatic, from start to end. By being fully automated, our solution provides significant cost advantages. It does not require any special security ink, special paper for printing the document, watermarked paper, holograms, chemicals used in verification, intaglio markers, etc., as required by other methods involving manual intervention. Our solution does not involve any of the above-mentioned costly paraphernalia, thus bringing the costs down. Our solution works for regular ink and paper used for printing. Apart from these, only scanner and printer are required, which are found in most of the organizations these days. Therefore, there are no additional costs to the company for verifying the authenticity of the presented document. In a preferred embodiment, a system for document authentication includes device for creating an authentic document. An image acquisition device is added for acquiring multiple images for creating set of test data. An image processor is added for extracting the parameters and determining the threshold for the test data and authentic document. A verification device is used for acquiring and verifying the authentic document by extracting parameters from the verified document. Most of the documents that need to be verified for authenticity are colored or grayscale. This invention is fully equipped to process grayscale and color document images. Examples of these documents are bank check, currency, ticket, banknote, stamp-paper, passport, photo-identification card, special event ticket, stock certificate, bond certificate, traveler's check, gift checks, gift vouchers, redemption vouchers, anti-counterfeiting label, tax stamp, postage stamp, birth certificate, mortgage papers, insurance certificate, vehicle registration card, deed, will, certificate of title, visa, paid reports, membership cards, etc. In another embodiment, the sub-pattern in the security mark may be used to extract information about the user or the owner of the document. While extracting the parameters, user rights information for a user is decrypted from sub patterns of the security mark on authentic document; and rights information is verified using stored information. The user information encrypted/ decrypted by shuffling the position of certain blocks of sub-sub-regions in the security mark to encode the ownership All documents cited in the description are incorporated herein by reference The present invention is not to be limited in scope by the specific embodiments and examples which are intended as illustrations of a number of aspects of the invention and any embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims. We claim: 1. A method for document authentication comprising the steps of: creating an authentic document with a security mark; obtaining multiple images of said authentic document with said security mark; - extracting a set of parameters from said security mark on each of said multiple images; - setting a set of thresholds based on each said set of parameters from said security mark on each of said multiple image; presenting said authentic document to a verification device; - extracting said set of parameters from said security mark on said authentic document; - obtaining set of values based on said set of parameters for said security mark on the authentic document; comparing said set of values to multiple thresholds obtained by said setting of thresholds; and authenticating a document subject to results of said comparing. 2. A method for document authentication as claimed in claim 1, wherein: - rights information for a owner is decrypted from sub patterns of said security mark on said authentic document; and - said rights information is verified using stored information. 3. A method for document authentication as claimed in claim 1 and claim 2, wherein said creating of said authentic document comprising the steps of: - obtaining a physical copy of an original document; and - embedding said security mark with said sub patterns in said physical copy. 4. A method for document authentication as claimed in claim 1 and claim 2, wherein said creating of said authentic document comprising the steps of: - obtaining a digital copy of an original document; and - embedding said security mark with said sub patterns in said digital copy. 5. A method for document authentication as claimed in claim 1, wherein said set of parameters comprising brightness, contrast, shapes of embedded Geometrical pattern, linearity of grayscales, variogram for texture detection and spatial frequency spectra for said security mark. 6 A method for document authentication as claimed in claim 1, wherein said setting of each said threshold comprising the steps of: - Collecting a set of test data from different combinations of image acquisition devices and printing devices for a group of fake and authentic documents; - Performing data analysis on said set of test data; - Deciding relative weights for said parameters based on results of said data analysis; and - Generating threshold based on said relative weights. 7 A method for document authentication as claimed in claim 6, wherein said data analysis comprising statistical analysis on said set of test data. 8 A method for document authentication as claimed in claim 6, wherein said data analysis comprising training of neural network using said set of test data. 9 A system for document authentication comprising: - A document creation device receiving an original document for creating an authentic document with a security mark; - A first image acquisition device receiving said authentic document for obtaining multiple images of said authentic document; - An image processing device for extracting a set parameters from said security mark on each of said multiple images and authentic document, and setting multiple thresholds and set of values; and - A verification device for authenticating and authentic document subject to comparison of said multiple thresholds and set of values. 10 A system for document authentication as claimed in claim 9, wherein said document creation comprising a printing device with a processor for embedding said security mark in said original document for creating said authentic document. 11 A system for document authentication as claimed 9, wherein said document creation comprising: - A second image acquisition device for acquiring a digital copy of said original document; - A processing device for embedding said security mark on said digital copy; and - a printing device for printing said digital copy with said security mark as said authentic document. 12. A system for document authentication as claimed in claim 9, wherein said first image acquisition device is a scanner. 13. A system for document authentication as claimed in claim 11, wherein said second image acquisition device is a scanner.

Documents:

3196-del-2005-abstract.pdf

3196-DEL-2005-Claims-(18-07-2012).pdf

3196-del-2005-claims.pdf

3196-DEL-2005-Correspondence Others-(18-07-2012).pdf

3196-del-2005-correspondence-others.pdf

3196-del-2005-description (complete).pdf

3196-DEL-2005-Drawings-(18-07-2012).pdf

3196-del-2005-drawings.pdf

3196-del-2005-form-1.pdf

3196-del-2005-form-18.pdf

3196-del-2005-form-2.pdf

3196-del-2005-form-3.pdf

3196-DEL-2005-GPA-(18-07-2012).pdf

3196-del-2005-gpa.pdf