CROSS-REFERENCE TO RELATED APPLICATIONSThis application is a Divisional Application of co-pending application Ser. No. 10/990,719 entitled “Document Security Utilizing Color Gradients” which is a continuation-in-part of prior co-pending application Ser. No. 10/819,700 entitled “Postage Indicia Including Color Bar Sequence to Aid In Authentication” filed on Apr. 7, 2004, which is a continuation-in-part of prior co-pending application Ser. No. 10/645,376 entitled “Postage Indicia Including Encoded Ink Characteristic Data”, filed Aug. 21, 2004. All of the prior applications are incorporated herein by reference in their entirety.
BACKGROUNDThis invention relates generally to the field of document security, and more particularly to printing and reading of document components to safeguard and verify the authenticity of a document.
It has been proposed to provide postage stamp printing devices that may be used by postal patrons to print their own postage stamps. However, it is an important consideration that counterfeiting of such postage stamps be deterred. More generally, it is desirable to provide printed security elements that are suitable for deterring counterfeiting of a wide variety of documents.
SUMMARYAccordingly, apparatus and methods for printing and inspecting machine-verifiable documents such as postage stamps are provided.
In one aspect, a method includes providing authentication data. The method further includes printing on a substrate a first representation of the authentication data, and printing on the substrate a second representation of the authentication data. The first representation includes a color region that represents the authentication data by a variation of at least one color component of the color region.
The variation may be substantially continuous, and may be periodic, such as sinusoidal. Both the first and second representations may be part of a postage meter indicium. As used herein, the term “postage meter indicium” should be understood to include, but not be limited to, a postage stamp printed by a personal postage stamp printer.
The substrate may be an envelope or a medium used for printing of postage stamps by a personal postage meter.
The first representation of the authentication data may be in the form of a color stripe. The second representation of the authentication data may be in the form of a barcode such as a two-dimensional barcode. The first and second representations may be printed on the substrate substantially simultaneously. More generally, the second representation of the authentication data may be in the form of any machine-readable symbology including a two-dimensional barcode, a one-dimensional barcode, or an OCR (optical character recognition) font.
In another aspect, a method of authenticating a document includes scanning at least a portion of the document. The method further includes analyzing a color region of the scanned portion of the document to detect first authentication data represented by a variation of at least one color component of the color region. The method also includes reading a second region of the scanned portion of the document to detect second authentication data. In addition, the method includes comparing the first and second authentication data.
The variation of the at least one color component may be substantially continuous, and may be periodic, such as sinusoidal. The document may be a postage meter indicium. The second region may include a barcode such as a two-dimensional barcode.
In still another aspect, a method includes scanning a color stripe and generating color gradient data indicative of at least one characteristic of a variation in intensity of at least one color component along the length of the color stripe.
The method may further include reading a barcode adjacent to the color stripe to generate barcode data, and comparing the barcode data with the color gradient data. The color stripe and the barcode may both be part of a postage meter indicium, and the comparing step may be for the purpose of authenticating the postage meter indicium. The barcode may be a two-dimensional barcode. The variation in intensity of the at least one color component may be a sinusoidal variation, and the at least one characteristic indicated by the color gradient data may be at least one of wavelength, amplitude and phase of the sinusoidal variation.
In another aspect, an apparatus includes a data mechanism for providing authentication data, and a printing mechanism for printing on a substrate a first representation of the authentication data and a second representation of the authentication data. The second representation includes a color region that represents the authentication data by a variation of at least one color component of the color region.
In still another aspect, an apparatus for authenticating a document includes a mechanism for scanning at least a portion of the document, a mechanism for analyzing a color region of the scanned portion of the document to detect first authentication data represented by a variation of at least one color component of the color region, a mechanism for reading a second region of the scanned portion of the document to detect second authentication data, and a mechanism for comparing the first and second authentication data.
In yet another aspect, a substrate (e.g., an envelope or an item of adhesive label stock) has printed thereon a first representation of authentication data and a second representation of authentication data. The second representation of the authentication data includes a color region that represents the authentication data by a variation of at least one color component of the color region.
In accordance with some aspects of the invention, postage indicia may be printed on adhesive label stock to form postage stamps. Each indicium may include a color stripe, which may vary from indicium to indicium. Variations such as gradients in one or more color components in the color stripe may be used to represent authentication data. Each indicium may also include another representation (e.g., in a two-dimensional barcode) of the authentication data. The authenticity of the indicium may be verified by scanning the indicium and then (e.g., automatically by machine) comparing the authentication data represented by the color stripe and by the other representation. Thus the presence of these elements in a postage indicium may help to deter counterfeiting. The color stripe may include subtle gradients that are not readily detectable or reproducible, to provide an additional layer of security.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Various features and embodiments are further described in the following figures, description and claims.
DESCRIPTION OF THE DRAWINGSThe accompanying drawings illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts.
FIG. 1 is a block diagram that illustrates a consumer postage stamp printing apparatus arranged in accordance with principles of the present invention.
FIG. 2 is a block diagram that illustrates an administrative server that is part of the apparatus ofFIG. 1.
FIG. 3 is a block diagram that illustrates a postage stamp printer that is part of the apparatus ofFIG. 1.
FIG. 4 illustrates a postage stamp printed in accordance with principles of the present invention, shown in juxtaposition with a print head for printing the postage stamp.
FIG. 5 shows on a larger scale a color stripe that is part of the postage stamp ofFIG. 4.
FIG. 6 is a graph that illustrates variations in two color components along the length of the color stripe ofFIG. 5.
FIG. 7 is a flow chart that illustrates a process that may be performed by the apparatus ofFIG. 1.
FIG. 8 is a block diagram of a device that may be provided in accordance with principles of the present invention to verify the authenticity of the postage stamp ofFIG. 4.
FIG. 9 is a flow chart that illustrates a process that may be performed by the verification device ofFIG. 8.
DETAILED DESCRIPTIONThe present invention includes apparatus and methods for allowing a postal customer to print his or her own postage stamps. The stamps are printed using a personal postage stamp printer. The stamp printer prints on adhesive label stock. The postage indicium printed to form the stamp includes a color stripe. Variations such as color gradients in the color components of the color stripe represent authentication data. The postage indicium also includes another representation of the authentication data. This other representation of the authentication data may present the data in encoded (and possibly also encrypted) form in a two-dimensional barcode or in another form. The color stripe and the 2D barcode vary from stamp to stamp. The 2D barcode is downloaded to the postage stamp printer from an administrative server, which handles charging of the postage to the customer's account.
To verify the stamp, the stamp is scanned and machine analysis is performed to detect the color component variations along the color stripe and to read the authentication data encoded in the 2D barcode. If these two pieces of information match, the authenticity of the stamp may be considered to be verified.
Referring now to the drawings, and particularly toFIG. 1, thereference numeral10 indicates generally a postage stamp printing apparatus in accordance with principles of the present invention. Theapparatus10 includes a personal postage stamp printer12 (hereinafter, “printer12”) shown in data communication with a postage fundsadministrative server14. While the description of the preferred embodiment shows a particular division of steps in the process of creating an indicium employing color gradients, any other division of steps is within the scope of the invention. In one embodiment, theprinter12 may be a postage meter that can perform all the functionality. In another embodiment, theprinter12 could provide the ability to format the barcode and/or the color stripe and receive only the security data from theadministrative server14.
Both theprinter12 and theserver14 will be described in more detail below, but their functions will now be generally described. Theprinter12 prints postage stamps on demand by the postal customer that has possession of the printer. The printer may operate independently of the server to print a stamp while not connected to the server. Theserver14 handles charging the customer's account for postage corresponding to stamps authorized to be printed by theprinter12. Theserver14 also generates and downloads to theprinter12 security-related information to be included in the images printed to form the postage stamps.
Theprinter12 may be in occasional data communication with theserver14 via, for example, a dial-up connection and/or the Internet.
FIG. 2 is a block diagram that illustrates an embodiment of theserver14 shown inFIG. 1. Generally, in some embodiments, theserver14, in its hardware aspects, may be constituted by conventional computer hardware. As seen fromFIG. 2, theserver14 may include aprocessing unit20. Theprocessing unit20 may be constituted by one or more processors of the type used in server computers, mainframe computers, minicomputers and/or desktop computers. Theserver14 may also include acommunication device22 in communication with theprocessing unit20. Thecommunication device22 may, for example, comprise one or more data communication ports by which theprocessing unit20 may exchange data with the printer12 (FIG. 1) and/or with other personal postage stamp printers. (Although only one printer is shown inFIG. 1, it should be understood that theserver14 may, at any one time or at various times, be in communication with a number, and potentially a large number, of different personal postage stamp printers.)
Theserver14 may further include anoutput device24 in communication with theprocessing unit20 and aninput device26 in communication with theprocessing unit20. Theoutput device24 may, for example, comprise one or more printers and/or one or more display monitors. Theinput device26 may include conventional devices such as a keyboard and/or mouse or other pointing device. Theinput device26 may be used by a human operator to control, administer, maintain or provide input to theserver14.
There may also be included in the server14 astorage device28 that is in communication with theprocessing unit20. Thestorage device28 may comprise, for example, a combination of magnetic, optical and/or semiconductor memory devices. In some embodiments, thestorage device28 may include one or more hard disk drives, RAM (random access memory), ROM and one or more drives for removable data storage media.
Thestorage device28 may store a number of programs for controlling theprocessing unit20. For example, thestorage device28 may storeserver functions software30 that enables theserver14 to function as a host to client devices such as the above-mentioned personal postage stamp printers that may be in communication with theserver14 from time to time. (In an alternative embodiment, a personal computer may be connected to a personal stamp printer.)
Thestorage device28 may also store postagefunds handling software32 that enables theserver14 to handle charges to customer accounts in respect of postage funds disbursed by printing of postage stamps authorized by theserver14.
Thestorage device28 may further storesoftware34 that enables theserver14 to generate image data that corresponds to 2D barcodes to be printed by the personal postage stamp printers as part of the postage indicia that form the stamps.
FIG. 3 is a block diagram that illustrates an embodiment of theprinter12. Theprinter12 includes aprint head50. Theprint head50 may, for example, be a color inkjet print head, or a thermal print head of a type suitable for color direct thermal printing. Theprint head50 may include afirst set52 of print elements and asecond set54 of print elements. The first set52 of print elements may be dedicated to printing the color stripe portion of the postage indicia printed by theprinter12. The second set54 of print elements may operate to print other portions of the postage indicia. In some embodiments, thefirst set52 of print elements may consist of 16 adjoining print elements at a lower end56 of theprint head50, and thesecond set54 of print elements may consist of approximately 280 print elements, being all of the other print elements of theprint head50. In some embodiments, the print head may print at a density of about 300 dpi (dots per inch) to produce indicia having a height of about one inch.
Theprinter12 also includes aprinter controller58 that is operatively coupled to theprint head50 to control theprint head50. Theprinter controller58 includes aprint head controller60 which is coupled to theprint head50 and which provides the direct control of theprint head50. Theprint head controller60 may be constituted by suitable processing or control circuitry and may provide general control functions for theprinter12.
Theprinter controller58 may also include aROM62 which may store a sequence of units of authentication data. Each unit of authentication data may be used to generate a respective color stripe as part of a respective postage stamp to be printed by theprinter12. Each unit of authentication data may, for example, be a string of data bits, and may consist of as little as a few data bits. In one embodiment, each unit of authentication data may consist of around two bytes to 18 bits of data, and may be represented in the corresponding color stripe by variations along the length of the color stripe in a single color component. For example, the color stripe may include superimposed sinusoidal variations in the color component corresponding to, say, six wavelengths, with three bits encoded in each wavelength as variations in phase and/or amplitude associated with each wavelength.
A portion (indicated at64) of theprint head controller60 may be dedicated (e.g., hard-wired) to control only thefirst set52 of print elements, and to cause theprint elements52 to print only color stripes as defined by the units of authentication data stored in theROM62. TheROM62 may be coupled to thededicated portion64 of theprint head controller60. Asecurity perimeter66 may be provided to prevent and/or deter (and/or to provide evidence of) tampering with theROM62, thededicated portion64 of theprint head controller60 and theprint elements52 to assure that theprint elements52 print only color stripes defined by the data in theROM62. Alternatively the printer controller may be capable of calculating a unit of authentication data for each postage stamp according to an algorithm from a seed value stored in ROM.
Theprinter controller58 may further include anon-volatile RAM68, which may be in communication with theprint head controller60. TheRAM68 may operate as working memory and may also store image data, to be discussed below, which is downloaded to theprinter12 from the server14 (FIG. 1) and which may be used to control theprint head50 to print one or more postage indicium elements prescribed by theserver14. In some embodiments,RAM68 may also function as program storage for a program to control theprint head controller60.
In addition, theprinter controller58 may include amodem70 through which theprinter12 may engage in data communication with theserver14, a mediamotion control circuit72 that controls feeding of a substrate (e.g., an item of adhesive label stock, which is not shown inFIG. 3) past theprint head50, and apower supply74 that provides power for at least part of theprinter12. The printer controller may also have a communication port (USB, serial, parallel, etc.) for communicating with a PC.
Theprinter12 may also include other components which are not indicated inFIG. 3. Such other components may include, for example, a housing, a user interface (e.g., one or more switches or buttons, a display, a touch screen, etc.), and mechanical components for transporting the stamp stock past theprint head50.
FIG. 4 illustrates apostage stamp80 printed by theprinter12 in accordance with principles of the present invention, and shown in juxtaposition with theprint head50 of the printer12 (the balance ofprinter12 is not shown inFIG. 4). Thepostage stamp80 includes apostage indicium82 formed on a substrate84 (e.g., adhesive label stock). In some embodiments, the substrate may be a type of stock suitable for thermal color printing.
The postage indicia82 may include alogo86 and adata field88 in which machine-readable data is printed. Thedata field88 may, for example, take the form of a two-dimensional barcode. Some or all of thedata field88 may be printed in accordance with the “Information-Based Indicia Program” (IBIP) promulgated by the U.S. Postal Service. The IBIP information may contain high-density variable cryptographically protected information in a two-dimensional barcode. The IBIP information may be used for security and marketing purposes. As will be seen, thedata field88 may also include data provided for security purposes (stamp authenticity verification purposes) in accordance with the principles of the present invention.
Thepostage indicium82 also includes acolor stripe90, printed in accordance with principles of the present invention. Thecolor stripe90 may be printed by theprint elements52 of theprint head50, so that thecolor stripe90 extends along the bottom of thepostage indicium82, adjacent to thelogo86 and thedata field88. Thelogo86 and thedata field88 are printed by theprint elements54 of theprint head50.
Thepostage indicium82 also includes analphanumeric data field91 that may include alphanumeric information such as amount of postage, date of printing/mailing and location/zip code of mailing.
Thepostage indicium82 is shown inFIG. 4 in juxtaposition with theprint head50. Thearrow mark92 is indicative of the direction in which thesubstrate84 is moved past theprint head50 to allow thefirst set52 of print elements to print thecolor stripe90 while the second set ofprint elements54 print other portions of theindicia82 such as thedata field88 and thelogo86. Thus thecolor stripe90 and thedata field88 may be printed simultaneously or substantially simultaneously.
As will be further discussed below, thedata field88 represents authentication data that is also represented by thecolor stripe90. That authentication data may, for example, be presented at a predetermined part (indicated at94) of thedata field88.
It should be understood that theindicia82 may include other elements, which are not shown, and which may include one or more finder or reference marks, to aid in subsequent scanning and parsing of theindicia82. In addition to or instead of representing the authentication data in a 2D barcode, the authentication data may be represented in other ways, such as a one-dimensional barcode, and/or alphanumeric characters that are machine- and/or human-readable. The 2D barcode may be omitted.
FIG. 5 shows thecolor stripe90 in isolation, and on a larger scale than inFIG. 4. (Because of the limitations of reproduction of drawings in patent publications, the color stripe is not in actuality shown in color.) The color stripe may includegaps96, each near a respective end of the color stripe. Thegaps96 may be used during subsequent analysis of the color stripe as reference points. In other embodiments, thegaps96 may be omitted, or may be supplemented or replaced by other reference marks, which are not shown.
In some embodiments, one or more color components of thecolor stripe90 may exhibit variations or gradients along the length ofcolor stripe90 to represent authentication data. In some embodiments, the variations may be continuous and/or periodic, such as sinusoidal variations. In some embodiments, sinusoidal variations of one color component may be superimposed upon each other.
In some embodiments, a linear gradient or linear gradients in a color component may be exhibited along at least a portion of the length of the color stripe. The slope of the gradient in such a case may be employed to represent authentication data.
In some embodiments, a variation in color component along at least a portion of the length of the color stripe may take the form of a sinusoid impressed on a linear gradient. In such a case, one or more of the slope of the linear gradient, and the wavelength, amplitude and phase of the sinusoid may be used to represent authentication data.
It should be understood that the appearance of the color stripe, and the authentication data represented thereby, may vary from indicium to indicium, and from embodiment to embodiment.
FIG. 6 graphically illustrates an example of variations in intensity in two color components that may be implemented in a particular color stripe in some embodiments. InFIG. 6, the horizontal axis represents displacement along the length of the color stripe, and the vertical axis represents variation in color intensity. The solid-line curve98 represents variation in a green color component, and the dashed-line curve102 represents variation in a red color component. It will be observed that both red and green color component variations are sinusoidal along the length of the color stripe. The red color component variation is a relatively large amplitude, large wavelength variation, that may be readily visible to the naked eye. The green color component variation is a relatively low amplitude, small wavelength variation, that may not be readily visible to the naked eye. The authentication data, in this example, may be represented by one or more of phase, amplitude and wave-length of either or both of the red and green color component variations. The low amplitude, small wavelength green variation may be particularly difficult to counterfeit.
FIG. 7 is a flow chart that illustrates a process by which one or more postage stamps, like thestamp80 shown inFIG. 4, may be printed in accordance with principles of the present invention. The process illustrated inFIG. 7 includes process steps performed by thepostage indicia printer12 or by theadministrative server14, or by theprinter12 and theserver14 operating in cooperation with each other. Accordingly,FIG. 7 is illustrative of software processes that control theprinter12 and theserver14 in accordance with principles of the present invention. The process illustrated inFIG. 7 includes process steps performed by the postagestamp printing apparatus10. These steps are performed by theprinter12 and theadministrative server14. The preferred division of the steps is described in the following.
Initially in the process ofFIG. 5 isstep104, at which the postage indicia printer12 (FIGS. 1 and 3) initiates a data communication session with the administrative server14 (FIGS. 1 and 2). This may be done, for example, by thepostage indicia printer12 dialing up theserver14 and engaging in a handshaking procedure with theserver14. The purpose of the communication session is to obtain authorization from theserver14 for theprinter12 to print one or more stamps, and also for theprinter12 to receive from theserver14 data to be used in printing the stamps. (In an alternative embodiment, the printer may receive the data to be used in printing the stamps via a connection to a PC and the Internet.)
Next in the process ofFIG. 7 isstep106, which in some embodiments may precede, or may occur simultaneously with,step104. Atstep106, theprinter12 determines a series of units of authentication data to be represented in the color stripes in respective stamps for which authorization is to be received from theserver14. In some embodiments, theprinter12 may determine the number of stamps for which authorization is to be requested. This number of stamps (as well as the denominations of the stamps, e.g.) may be determined based on input from a user of theprinter12. The printer12 (for example, by operation of theprint head controller60,FIG. 3) may then refer to units of authentication data in theROM62 on the basis of an index value stored in theRAM68. The index value may point to an address in theROM62 which contains the first of the units of authentication data. In other embodiments, theROM62 may be omitted, and theprinter12 may generate the authentication data by a random process, or by a pseudo-random process that uses the serial number of theprinter12 as an input. In other embodiments, the user may request a number of stamps of various denominations through an Internet web service linked to theadministrative server14.
In any event, atstep108 theprinter12 transmits to theserver14 the authentication data to be included in the stamps for which authorization is being requested. This may be done, in part, by reading out authentication data from theROM62 based on the index value referred to above. After reading out the authentication data and transmitting the authentication data to theserver14, the index value may be updated to point to the next address in theROM62 after the locations at which the transmitted authentication data was stored.
Atstep110, theserver14 generates image data that represents the data fields88 of the stamps now being authorized by theserver14 for printing by theprinter12. As part of the process step of generating the data field image data, theserver14 may encrypt the authentication data received from theprinter12 using a secret key held in theserver14 and may then encode the encrypted authentication data to include the encrypted authentication data in the data for the data field. The data field for each stamp to be printed by theprinter12 may thus represent authentication data encrypted and encoded by theserver12. In some embodiments, the authentication data may be encoded for inclusion in the data field without encrypting.
Before, after or simultaneously withstep110 is astep112, at which theserver14 initiates a charge to the customer's account for the postage to be represented by the stamps now being authorized for printing. For example, theserver14 may transfer a suitable quantity of funds from a deposit account maintained by the holder of theprinter12 to an account for the benefit of a postal authority such as the U.S. Postal Service. In other embodiments, the server may initiate a charge to a credit card account or another type of account maintained by the holder of theprinter12 at a financial institution.
Afterstep110, and either before, after or simultaneously withstep112, isstep114, at which theserver14 downloads to theprinter12 the data field image data generated by theserver14 atstep110. That is, theserver14 transmits the data field image data to theprinter12, and the printer12 (e.g., themodem70, theprint head controller60 and the RAM68) receives the data field image data from theserver14. The data field image data for each stamp of the batch of stamps being authorized may be stored inRAM68 or non-volatile memory.
The downloading of data may also include image data that represents thelogo86 to be included in the stamps. In another embodiment, the image data for the logo may have been loaded into theprinter12 at the factory at which theprinter12 was manufactured. In still other embodiments, the logo may be replaced with a custom or customizable image selected by the holder of the stamp printer, and the image data for such image may be downloaded from the server to the stamp printer or pre-stored in the stamp printer.
Followingstep114 isstep116, at which the data communication session between theserver14 and theprinter12 is ended.
Step118 followsstep116 in the process illustrated inFIG. 5. Atstep118, theprinter12 prints the stamps authorized by theserver14 during the session. (In other embodiments, the stamps may be printed during the session. In still other embodiments, the printer prints some stamps during the session with the server or afterward, while storing authorization and data for further stamps in non-volatile memory for later printing.) As part of printing each stamp, thefirst set52 of print elements (FIGS. 3 and 4) of theprint head50 print a color stripe90 (FIG. 4) that represents the authentication data for the stamp in question stored. It will be understood that the authentication data had been communicated to theserver14 during the session, and that the appropriate address in theROM62 is indicated by an index value stored in theRAM68 or non-volatile memory. The printing of thecolor stripe90 by thefirst set52 of print elements may be controlled by first driver software (not separately shown) which may be stored inRAM68 orROM62.
Also as part of the printing of the same stamp, thesecond set54 of print elements of theprint head50 print thedata field88 of the stamp, including the authentication data represented by thecolor stripe90. It will be recalled that the authentication data had been encoded by theserver14. The second set54 ofprint elements54 also prints thelogo86 and other portions of theindicium82. The printing performed by thesecond set54 of print elements may be controlled by second driver software (not separately shown) which may be stored inRAM68 orROM62. Other methods of representing the authentication data could also be used in addition to or instead of the two dimensional barcode shown inFIG. 4.
It will be appreciated that the components and/or the layout of theindicium82 may be changed. For example, the location of thecolor stripe90 in theindicium82 may be changed. Thedata field88 may take a form other than a two-dimensional barcode, and thelogo86 may be omitted.
FIG. 8 is a block diagram that illustrates a stamp reading andverification device120 provided according to principles of the present invention.
Thestamp verification device120 ofFIG. 6 includes ascanner122 that is arranged to scan apostage stamp80 to capture a color image of the indicium82 (FIG. 4, not separately shown inFIG. 8) from thepostage stamp80. (At the time of scanning by theverification device120, thestamp80 may be affixed to a mail piece, which is not separately shown.) Thedevice120 also includes ananalysis portion126 which is coupled to thescanner122 to receive from thescanner122 image data which is generated by thescanner122 and represents the image of the indicia. The image data is represented byblock128 in theanalysis portion126. The image data block128 may comprise, for example, storage and/or preliminary analysis of the image data. Theanalysis portion126 includes a data field reading (e.g., 2D barcode reading) block130 and a colorstripe analysis block132, both of which operate on the color image data ofblock128. Theanalysis portion126 further includes a verificationprocessing portion block134 which receives data, including authentication data read from thedata field88 by the datafield reading block130 and authentication data extracted from thecolor stripe90 by the colorstripe analysis block132.
In some embodiments, thestamp verification device120 may also include a spectral analysis block136 (shown in phantom) to determine at least one spectral characteristic of thestamp80 on the basis of the image data from theimage data block128, and to provide a result of the spectral analysis to the verificationprocessing portion block134.
In some embodiments, thescanner122 may be a conventional high-quality scanner, such as the Epson “Expression” model 1680. Image data generated by thescanner122 may be provided in raw form to the colorstripe analysis block132 to facilitate reliable detection of color component variations by the colorstripe analysis block132. In other embodiments, the image data generated by thescanner122 may be pre-processed by conventional driver software, such as the “VueScan” driver available from Hamrick Software, Phoenix, Ariz.
Operation of thestamp verification device120 will now be described with reference toFIG. 7, which is a flow chart that illustrates an indicium reading and verification process performed by thedevice120.
The process ofFIG. 7 begins with astep140 at which thescanner122 scans thestamp80. Then, atstep142, the resulting digital image data is stored in theimage data block128. Atstep144, the colorstripe analysis block132 detects variations in color components along the length ofcolor stripe90, on the basis of the image data stored in theimage data block128, to extract authentication data from thecolor stripe90.
Atstep146, the datafield reading block130 reads the data field88 (as represented in the image data stored in image data block128) to read authentication data from thedata field88. The reading of the authentication data by the datafield reading block130 may include decrypting the authentication data. The decrypting may involve using a public key and may verify that the authentication data encoded in thedata field88 was generated by theadministrative server14 using the secret key referred to in connection withstep110 ofFIG. 7.
Continuing to refer toFIG. 7, atstep148, the authentication data extracted from the color stripe by the colorstripe analysis block132 and the authentication data read from thedata field88 by the datafield reading block128 are compared by the verificationprocessing portion block134. Adecision block150 may follow or form part ofstep148. Atdecision block150, it is determined whether the authentication data extracted from the color stripe and the authentication data read from the data field match. If so (and if it is determined atdecision block152, shown in phantom, that thestamp80 exhibits a proper spectral response for the authorized stock on which stamps are to be printed), thestamp80 may be considered to be authenticated (step154). If the authentication data extracted from the color stripe and the authentication data read from the data field are determined not to match (or if thestamp80 does not exhibit the proper spectral response), thestamp80 may be found to be counterfeit (step156).
With a system as described herein, including printing of a color stripe in a postage indicium to form a postage stamp printed on demand by a personal postage stamp printer, along with corresponding authentication data encoded as part of a data field that is separate from the color stripe, and analyzing the color stripe and reading the data field to confirm that the authentication data from the data field matches the authentication data from the color stripe, authentication of a postage stamp that is printed on demand can be facilitated and automated, and counterfeiting of such postage stamps can be detected and deterred. Moreover, with the authentication of a postage stamp by comparing authentication data from the color stripe to authentication data in the data field, it may be the case that the stamp verification device does not require access to a central database, thereby significantly reducing the cost and increasing the convenience of the counterfeit-prevention system. With this system, it also may not be necessary to account for blank stamp printing stock. Furthermore, a color stripe as described herein may present significant technical challenges to a would-be counterfeiter.
In some embodiments, the inputs for the datafield reading block130 and the colorstripe analysis block132 need not be obtained via a shared scanner or a shared image data store. For example, data field reading and color stripe analysis may proceed in separate channels.
A stamp authentication device in accordance with some embodiments may read other data from the stamp to be authenticated in addition to the authentication data described above, and may perform other tests in addition to comparing authentication data extracted from the color stripe with authentication data read from the data field and detecting a spectral response of the stamp.
In some embodiments, a color stripe and a data field which includes corresponding authentication data may be included in an indicium printed (by a postage meter, for example) directly on a mail piece (envelope) or otherwise used for purposes other than printing a postage stamp on demand from a personal postage stamp printer. Thus, the verification process described herein may be employed to verify postage meter indicia as well as postage stamps printed on adhesive stock, with or without pictorial images as part of the postage indicia.
The order in which process steps are described herein and/or indicated in the drawings is not meant to imply a fixed order of steps, and it is contemplated that the process steps may be performed in any order that is practicable.
In some embodiments, the stamp printer may generate image data for the data field (e.g. 2D barcode) on the basis of encrypted authentication data received from the server.
A color stripe as described herein may be printed as a security element in other types of documents besides postage meter indicia or postage stamps printed on demand. Such a color stripe may be printed on substrates other than postage stamp stock or envelopes. Authentication data may also be represented by color component gradients in color fields that are not in the shape of a stripe.
The words “comprise,” “comprises,” “comprising,” “include,” “including,” and “includes” when used in this specification and in the following claims are intended to specify the presence of stated features, elements, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, elements, integers, components, steps, or groups thereof.
A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.