Validation method and apparatus for identification documents

Abstract

An apparatus configured to perform or control obtaining or causing obtaining an image of at least a part of a surface of a document. The apparatus deriving or causing the derivation of a representation of the at least a part of the surface from the image. The representation comprising a set of values respectively representing a corresponding set of height levels. The apparatus generates or causes the generating of a string of characters based on the representation of the part of the surface. The string of characters comprising a first portion representative of the set of height levels of the corresponding sections of the part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters. The apparatus associates or causes the associating of information representing the string of characters with identification information of the document.

Claims

1. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause an apparatus at least to perform or control: obtaining or causing obtaining an image of at least a part of a surface of a document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating a string of characters based on the representation of the at least a part of the surface, the string of characters comprising at least a first portion representative of the set of height levels of the corresponding sections of the at least a part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters; associating or causing associating information representing the string of characters with identification information of the document.

2. The apparatus according to claim 1, wherein associating the information representing the string of characters with the identification information comprises at least one of the following: storing or causing storing the information representing the string of characters with the identification information of the document; providing or causing providing the information representing the string of characters in association with the identification information of the document to be accessible by at least one external apparatus, in particular via a communication path.

3. The apparatus according to claim 1, wherein obtaining the image comprises obtaining the image using a digital camera or a scanner.

4. The apparatus according to claim 3, wherein obtaining the image of the at least a part of the surface comprises: applying or causing applying ultraviolet, UV, infrared, IR, and/or white light to the at least a part of the surface.

5. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause an apparatus at least to perform or control: obtaining or causing obtaining first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document; determining or causing determining, based on the obtained first information, whether or not the first string of characters is present in a database; if the first string of characters is not present in the database: determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the first string of characters is below a first predefined threshold; and outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the first string of characters is below the first predefined threshold.

6. The apparatus according to claim 5, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to perform or control: if the first string of characters is not present in the database, the following steps (a), (b), and (c): (a) obtaining or causing obtaining at least second information representing at least one first model string of characters with a first portion representative of a first model set of height levels of the corresponding sections of the at least a part of the surface of the first document; (b) determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the at least one first model string of characters and/or the first string of characters is below a second predefined threshold; (c) outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the at least one first model string of characters and/or the first string of characters is below the second predefined threshold.

7. The apparatus according to claim 6, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to perform or control: if at least one second string of characters is determined to be present in the database, the at least one second string of characters comprising a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of at least one respective second document corresponding to the at least one second string of characters and the distance of which to the first string of characters and/or to the at least one first model string of characters is below a third predefined threshold, the following steps (a), (b) and (c): (a) obtaining or causing obtaining, for each one of the at least one second string of characters, at least third information representing at least one respective second model string of characters corresponding to the at least one second string of characters with a first portion being representative of a second model set of height levels of corresponding sections of at least a part of the surface of the respective second document corresponding to the at least one second string of characters; (b) determining or causing determining whether or not at least one string of characters of the at least one second string of characters and the at least one corresponding second model string of characters is present in the database for which a distance to any one of the first string of characters and/or the at least one first model string of characters is below a fourth predefined threshold; and (c) if at least one string of characters of the at least one second string of characters is found, the distance of which to any one of the first string of characters and/or the at least one first model string of characters is below the fourth predefined threshold, outputting or causing outputting corresponding information.

8. The apparatus according to claim 5, wherein for each one of the at least one first model string of characters, the first model set of height levels of the corresponding sections of the at least a part of the surface of the first document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions; and/or wherein for each one of the at least one second model string of characters, the second model set of height levels of the corresponding sections of the at least a part of the surface of the second document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions.

9. The apparatus according to claim 5, wherein the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters each comprise respective second portions; and wherein respective mutual distances between the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters are determined based on the metric function and based on the respective second portions.

10. The apparatus according to claim 5, wherein obtaining the first information comprises: obtaining or causing obtaining an image of at least a part of a surface of the first document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating the first string of characters based on the representation of the at least a part of the surface; or receiving or causing receiving the first information via a network connection.

11. The apparatus according to claim 10, wherein a second portion of the first string of characters is generated based on a function of the representation and/or of the first portion of the first string of characters.

12. The apparatus according to claim 5, wherein obtaining the image comprises obtaining the image using a digital camera or a scanner.

13. The apparatus according to claim 12, wherein obtaining the image of the at least a part of the surface comprises: applying or causing applying ultraviolet, UV, infrared, IR, and/or white light to the at least a part of the surface.

14. The apparatus according to claim 5, wherein the string of characters, the first string of characters, the second string of characters, the at least one first model string of characters, and/or the second model string of characters further comprises a third portion different from the first and/or the second portion and being determined based on a hash function of the first portion and/or the second portion and/or comprising a checksum of the first portion and/or the second portion.

15. A method performed by at least one second apparatus, the method comprising: obtaining or causing obtaining first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document; determining or causing determining, based on the obtained first information, whether or not the first string of characters is present in a database; if the first string of characters is not present in the database: determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the first string of characters is below a first predefined threshold; and outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the first string of characters is below the first predefined threshold.

16. The method according to claim 15, further comprising: if the first string of characters is not present in the database, the method further comprises the following steps (a), (b), and (c): (a) obtaining or causing obtaining at least second information representing at least one first model string of characters with a first portion representative of a first model set of height levels of the corresponding sections of the at least a part of the surface of the first document; (b) determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the at least one first model string of characters and/or the first string of characters is below a second predefined threshold; (c) outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the at least one first model string of characters and/or the first string of characters is below the second predefined threshold.

17. The method according to claim 16, further comprising: if at least one second string of characters is determined to be present in the database, the at least one second string of characters comprising a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of at least one respective second document corresponding to the at least one second string of characters and the distance of which to the first string of characters and/or to the at least one first model string of characters is below a third predefined threshold, the method further comprises the following steps (a), (b) and (c): (a) obtaining or causing obtaining, for each one of the at least one second string of characters, at least third information representing at least one respective second model string of characters corresponding to the at least one second string of characters with a first portion being representative of a second model set of height levels of corresponding sections of at least a part of the surface of the respective second document corresponding to the at least one second string of characters; (b) determining or causing determining whether or not at least one string of characters of the at least one second string of characters and the at least one corresponding second model string of characters is present in the database for which a distance to any one of the first string of characters and/or the at least one first model string of characters is below a fourth predefined threshold; and (c) if at least one string of characters of the at least one second string of characters is found, the distance of which to any one of the first string of characters and/or the at least one first model string of characters is below the fourth predefined threshold, outputting or causing outputting corresponding information.

18. The method according to claim 15, wherein for each one of the at least one first model string of characters, the first model set of height levels of the corresponding sections of the at least a part of the surface of the first document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions; and/or wherein for each one of the at least one second model string of characters, the second model set of height levels of the corresponding sections of the at least a part of the surface of the second document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions.

19. The method according to claim 15, wherein the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters each comprise respective second portions; and wherein respective mutual distances between the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters are determined based on the metric function and based on the respective second portions.

20. The method according to claim 15, wherein obtaining the first information comprises: obtaining or causing obtaining an image of at least a part of a surface of the first document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating the first string of characters based on the representation of the at least a part of the surface; or receiving or causing receiving the first information via a network connection.

21. The method according to claim 20, wherein a second portion of the first string of characters is generated based on a function of the representation and/or of the first portion of the first string of characters.

22. A non-transitory computer readable storage medium in which a computer program is stored, the computer program when executed by a processor causing an apparatus or system to perform or control: obtaining or causing obtaining first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document; determining or causing determining, based on the obtained first information, whether or not the first string of characters is present in a database; if the first string of characters is not present in the database: determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the first string of characters is below a first predefined threshold; and outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the first string of characters is below the first predefined threshold.

23. A method performed by at least one first apparatus, the method comprising: obtaining or causing obtaining an image of at least a part of a surface of a document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating a string of characters based on the representation of the at least a part of the surface, the string of characters comprising at least a first portion representative of the set of height levels of the corresponding sections of the at least a part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters; associating or causing associating information representing the string of characters with identification information of the document.

24. A non-transitory computer readable storage medium in which a computer program is stored, the computer program when executed by a processor causing an apparatus or system to perform or control: obtaining or causing obtaining an image of at least a part of a surface of a document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating a string of characters based on the representation of the at least a part of the surface, the string of characters comprising at least a first portion representative of the set of height levels of the corresponding sections of the at least a part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters; associating or causing associating information representing the string of characters with identification information of the document.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a block diagram of an exemplary embodiment of a system according to the invention;

(2) FIG. 2 is a block diagram of an exemplary embodiment of an apparatus according to the first aspect of the invention;

(3) FIG. 3 is a block diagram of an exemplary embodiment of an apparatus according to the second aspect of the invention;

(4) FIG. 4 is a block diagram of a further exemplary embodiment of an apparatus according to the second aspect of the invention;

(5) FIG. 5 is a flow chart illustrating an exemplary embodiment of a method according to the first aspect of the invention;

(6) FIG. 6 is a flow chart illustrating an exemplary embodiment of a method according to the second aspect of the invention;

(7) FIG. 7A is a first part of a flow chart illustrating a further exemplary embodiment of a method according to the invention;

(8) FIG. 7B is a second part of the flow chart of FIG. 7A.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

(9) FIG. 1 is a schematic illustration of an example embodiment of a system 10 comprising a registration device 2 (an example of the at least one first apparatus), a mobile device 4 (an example of the at least one second apparatus) and a server 3 storing database 30. It is noted that registration device 2 may incorporate and/or correspond to a further mobile device. Further, each of registration device 2 and mobile device 4 comprises or is connected to a camera (not shown) for acquiring an image of passport 1 (an example of a document addressable by a method according to the first and by a method according to the second aspect) shown in FIG. 1. It is further noted that instead of or in addition to at server 3 and mobile device 4, the respective steps of a method in accordance with the second aspect may be similarly performed by a single dedicated device comprising a corresponding database (or being connected to a corresponding network database).

(10) Passport 1 is shown at stage A of FIG. 1 being under registration and at stage B of FIG. 1 being verified. In other words, registration stage A may correspond to a stage after production of the passport at which passport 1 is (e.g. officially) registered in combination with details of its holder (e.g. in combination with necessary personal information of the passport holder). Verification stage B may correspond to a later stage at which the passport holder is identified by means of the passport and at which to this end the passport is verified. Such later stage may correspond to a traffic control situation where police personnel checks an identity of a car driver, to a passenger control situation at an airport, or to any different situation where validity of a document needs to be confirmed. Light source 5 (which may comprise one or more light sources) provides a lighting condition for the registration process and may correspond to or comprise a ultraviolet (UV), an infrared (IR) and/or a white light source.

(11) As shown in FIG. 1, registration device 2 acquires (an example of obtaining) an image of at least part of a surface of passport 1. Based on the obtained image, registration device 2 may then derive a representation of the at least a part of the surface from the image, e.g. a two-dimensional matrix comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface. Based on the representation, registration device 2 may then generate a string of characters (a code) comprising a first portion representative of the set of height levels and a second portion generated based on a function of the first portion. The code may further include a third portion which may comprise in particular a checksum of the first portion. The registration device 2 may then associate information (e.g. data) representing the string of characters with identification information of the document. To this end, registration device 2 may for example transmit the information representing the string of characters in association with a serial number of the passport and/or personal information of the passport holder to the server via communication path 23. Alternatively or in addition, in a case in which a corresponding database is stored at the registration device 2, registration device 2 may store the information representing the string of characters in association with the identification information of the document at the database of the registration device 2.

(12) As further shown in FIG. 1, mobile device 4 may perform actions for verification of the passport 1 at a later stage B. For example, mobile device 4 may obtain an image of at least a part of a surface of passport 1 using e.g. a digital camera comprised by mobile device 4. Based on the obtained image, mobile device 4 may then derive a representation of the at least a part of the surface from the image, for example a two dimensional matrix comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface. It is noted that parameters such as matrix dimension may be preset and may be employed commonly at registration device 2 and at mobile device 4. Based thereon, mobile device 4 may then generate a first string of characters based on the representation of the at least a part of the surface. In this way, mobile device 4 may thus obtain first information representing the first string of characters. It is noted that mobile device 4 may alternatively receive the first information via a network connection, for example in a case in which verification processing is outsourced to a network device, e.g. to server 3 which may for example process an image obtained at device 4 and which may sent the first information to device 4 via communication path 34. Based on the obtained first information, mobile device 4 may then determine whether or not the first string of characters is present in a database. Thereby, the database may be a database comprised by or connected to mobile device 4 (having obtained the corresponding information from registration device 2 via communication path 24). Alternatively, as shown in FIG. 1, mobile device 4 may determine, based on the obtained first information, whether or not the first string of characters is present in database 30 via communication with server 3 (an example of an external network device) connected to database 30 via communication path 34. In the affirmative case, mobile device 4 may e.g. display a confirmation message (“passport verified”) and/or may display identification information of a document associated in database 30 with the first string of characters using display 41. If the first string of characters is not present in the database mobile device 4 may determine based on the metric function disclosed above, whether or not at least one second string of characters is present in the database, a distance of which to the first string and/or to the at least one first model string of characters disclosed above is below a first predefined threshold. If at least one second string of characters is present in the database, the distance of which to the first string of characters and/or the first model string of characters is below the first predefined threshold, mobile device 4 may output corresponding information, e.g. via display 41.

(13) It is noted that any of communication paths 23, 24 and 34 described above may be a direct or indirect communication path. For example, any of communication paths 23, 24 and 34 may comprise one or more hops, for example one or more communication links or communication connections. In the context of the present disclosure communication paths are to be understood as (bi-directional) wireless communication connections like 2G/3G/4G/5G cellular wireless connections, Device-to-Device (D2D) communication paths, (bi-directional) wireless communication connections such as Wireless Local Area Network (WLAN) connections, and/or wired computer connections such as buses including in particular USB connections.

(14) FIG. 2 is a block diagram of an exemplary embodiment of registration device 2 (an example of the at least one first apparatus). In the following, it is assumed that registration device 2 of system 10 of FIG. 1 corresponds to registration device 2 of FIG. 2.

(15) Registration device 2 comprises a processor 200. Processor 200 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 200 executes a computer program code to perform any one embodiment of the disclosed method according to the first aspect (e.g. the steps of any one embodiment of the disclosed method) stored in program memory 201 or a part thereof (e.g. at least some steps of any one embodiment of the disclosed method) (as for instance further described below with reference to FIG. 5), and interfaces with a main memory 202. Accordingly, program memory 201 may contain an operating system for processor 200. Some or all of memories 201 and 202 may also be included into processor 200. One of or both of memories 201 and 202 may be fixedly connected to processor 200 or at least partially removable from processor 200, for example in the form of a memory card or stick.

(16) Processor 200 further controls a communication interface 203 which is configured to communicate via a communication network. Registration device 2 may use communication interface 203 to communicate with external apparatuses such as server 3 (via communication path 23) or mobile device 4 (via communication path 24). In the following, it is assumed that communication interface 203 is a wireless or wired communication interface configured for communicating using (bi-directional) communication connections like 2G/3G/4G/5G cellular wireless connections, Device-to-Device (D2D) communication paths, (bi-directional) wireless communication connections such as Wireless Local Area Network (WLAN) connections, or wired computer connections such as buses including in particular USB connections. In an exemplary embodiment, communication interface 203 may be or may comprise a 2G/3G/4G/5G and/or WiFi radio transceiver. For example, registration device 2 may use communication interface 203 to transmit information representing the string of characters associated with identification information of the document to server 3 via communication path 23 and/or to mobile device 4 via communication path 24.

(17) Moreover, processor 200 controls a camera 205 (e.g. a digital camera) configured for obtaining an image of at least a part of a surface of passport 1 (as shown in FIG. 1).

(18) The components 201 to 205 of registration device 2 may for example be connected with processor 200 by means of one or more serial and/or parallel busses.

(19) It is to be understood that registration device 2 may comprise various other components like a user interface for receiving user input.

(20) FIG. 3 is a block diagram of an exemplary embodiment of server 3 (which may be a further example of the at least one first and/or second apparatus). In the following, it is assumed that server 3 of system 10 of FIG. 1 corresponds to server 3 of FIG. 3. Server 3 is an example of the disclosed network device and may correspond to or comprise a network server and/or server cloud connected to a network such as a local area network and/or the Internet.

(21) Server 3 comprises a processor 300. Processor 300 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 300 executes a computer program code (e.g. computer program code causing server 3 to store information representing a string of characters in association with identification information of a document as received from registration device 2, and/or to obtain first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document, e.g. based on an image received from mobile device 4) stored in program memory 301, and interfaces with a main memory 302. Accordingly, program memory 301 may contain an operating system for processor 300. Some or all of memories 301 and 302 may also be included into processor 300. One of or both of memories 301 and 302 may be fixedly connected to processor 300 or at least partially removable from processor 300, for example in the form of a memory card or stick.

(22) Processor 300 further controls a communication interface 303 which is configured to communicate via a communication network. Server 3 may use communication interface 303 to communicate with registration device 2 and/or with mobile device 4 of system 10 via said local area network and/or the Internet. Communication paths 23 and 34 may thus at least in part correspond to or comprise communication connections within such local area network and/or the Internet. Communication interface 303 may in addition or alternatively correspond to or comprise a wireless communication interface configured for communicating via a cellular network (e.g. to transmit and receive cellular radio signals). For example, communication interface 303 may be or may comprise a 2G/3G/4G/5G radio transceiver. It is however to be understood that the invention is not limited to this. Interface 303 may similarly be a wireless communication interface configured for communicating via a Device-to-Device (D2D) communication path or a (bi-directional) wireless communication connection in a Wireless Local Area Network (WLAN). For example, server 3 may use communication interface 303 to receive information representing a string of characters in association with corresponding identification information of a document from registration device 2 via communication path 23 and/or to transmit stored information to mobile device 4 via communication path 34.

(23) The components 301 to 303 of server 3 may for example be connected with processor 300 by means of one or more serial and/or parallel busses.

(24) It is to be understood that server 3 may comprise various other components like a user interface for receiving user input.

(25) FIG. 4 is a block diagram of an exemplary embodiment of mobile device 4 (a further example of the at least one second apparatus). In the following, it is assumed that mobile device 4 of FIG. 1 corresponds to mobile device 4 of FIG. 4.

(26) Mobile device 4 comprises a processor 400. Processor 400 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 400 executes a computer program code stored in program memory 401 (e.g. computer program code causing mobile device 4 to perform any one embodiment of the disclosed method according to the second aspect (e.g. the steps of any one embodiment of the disclosed method) or a part thereof (e.g. at least some steps of any one embodiment of the disclosed method) (as for instance further described below with reference to FIG. 6), when executed on processor 400), and interfaces with a main memory 402. Program memory 401 may also contain an operating system for processor 400 and further data. Some or all of memories 401 and 402 may also be included into processor 400. One of or both of memories 401 and 402 may be fixedly connected to processor 400 or at least partially removable from processor 400, for example in the form of a memory card or stick.

(27) A program memory (e.g. program memory 201 and/or program memory 401) may for example be a non-volatile memory. The program memory (e.g. program memory 201 and/or program memory 401) may for instance be a FLASH memory (or a part thereof), any of a ROM, PROM, EPROM, MRAM or a FeRAM (or a part thereof) or a hard disc (or a part thereof), to name but a few examples. For example, a program memory may for instance comprise a first memory section that is fixedly installed, and a second memory section that is removable, for instance in the form of a removable SD memory card.

(28) A main memory (e.g. main memory 201 and/or main memory 401) may for example be a volatile memory. It may for example be a DRAM memory, to give non-limiting example. It may for instance be used as a working memory for a processor (e.g. processor 200 and/or processor 400) when executing an operating system and/or programs.

(29) Processor 400 further controls a communication interface 403 which is configured to communicate via a communication network. Mobile device 4 may use communication interface 403 to communicate with external apparatuses such as server 3 (via communication path 34) or registration device 2 (via communication path 24). In the following, it is assumed that communication interface 403 is a wireless or wired communication interface configured for communicating using (bi-directional) communication connections like 2G/3G/4G/5G cellular wireless connections, Device-to-Device (D2D) communication paths, (bi-directional) wireless communication connections such as Wireless Local Area Network (WLAN) connections, or wired computer connections such as buses including in particular USB connections. In an exemplary embodiment, communication interface 403 may be or may comprise a 2G/3G/4G/5G and/or WiFi radio transceiver. For example, mobile device 4 may use communication interface 403 to determine, based on the obtained first information, whether or not the first string of characters is present in database 30 via communication with server 3 via communication path 34.

(30) Moreover, processor 400 controls a camera 405 (e.g. a digital camera) configured for obtaining an image of at least a part of a surface of passport 1 (as shown in FIG. 1).

(31) The components 401 to 405 of mobile device may for instance be connected with processor 400 by means of one or more serial and/or parallel busses.

(32) It is to be understood that mobile device 4 may comprise various other components like a user interface for receiving user input.

(33) FIG. 5 is a flow chart 500 illustrating an exemplary embodiment of a method according to the first aspect of the invention. Without limiting the scope of the invention, it is assumed in the following that registration device 2 as disclosed above with respect to FIGS. 1 and 2 performs the steps of flow chart 500. It is noted that the steps of flow chart 500 could likewise be performed by a mobile device substituting or used in combination with registration device 2.

(34) In a step 501, the registration device 2 obtains an image of at least a part of a surface of a document, in particular of passport 1, using camera 205.

(35) In a step 503, the registration device 2 derives a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface. For example, the registration device 2 may perform processes of filtering the image for example for reducing artifacts due to imperfect optics and/or lighting conditions and may thereby optimize the image. The registration device 2 may then convert the image into a two dimensional matrix where each dimension represents a corresponding dimension of the image and where each entry represents a corresponding height value of a respective section of the image.

(36) In a step 505, the registration device 2 generates a string of characters based on the representation of the at least a part of the surface, the string of characters comprising at least a first portion representative of the set of height levels of the corresponding sections of the at least a part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters. In a simple example, the registration device may place the entries of the matrix one after the other in order to obtain the first portion of the string of characters. Based thereon, using a statistical function such as a suitable averaging function, the registration device 2 may generate the second portion of the string of characters as a portion which varies little when entries of the matrix vary little, e.g. as a result of small changes in lighting conditions. As explained above, the string of characters may further comprise a third portion comprising a checksum of the first portion for verifying the string of characters.

(37) In a step 507, registration device 2 associates information representing the string of characters with identification information of the document. For example, registration device 2 may transmit information representing the string of characters in association with a serial number of the passport and/or personal information of the passport holder to server 3 via communication path 23 to be stored in database 30.

(38) FIG. 6 is a flow chart 600 illustrating an exemplary embodiment of a method according to the second aspect of the invention. Without limiting the scope of the invention, it is assumed in the following that mobile device 4 as disclosed above with respect to FIGS. 1 and 4 performs the steps of flow chart 600. It is noted that the steps of flowchart 600 may further be performed by server 3 of FIG. 1. Further, in alternative embodiments, the steps of flowchart 600 may likewise be performed by one or more fixedly installed devices, installed e.g. at an airport or at any official building where verification of official documents is performed.

(39) In a step 601, mobile device 4 obtains first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document. As mentioned above, mobile device 4 may obtain an image of a part of a surface of passport 1 using camera 405, may derive a representation of the surface from the image and may generate the first string of characters based on the representation. Further, for example, server 3 may perform step 601 by obtaining the first information from mobile device 4 via communication path 34.

(40) In a step 603, mobile device 4 determines, based on the obtained first information, whether or not the first string of characters is present in a database, e.g. in database 30 via communication with server 3 via communication path 34. Alternatively, server 3 may perform step 603 by determining whether or not the first string of characters is present in database 30.

(41) In a step 605, if the first string of characters is not present in the database, e.g. not in database 30, mobile device 4 determines, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the first string of characters is below a first predefined threshold. The mobile device 4 may perform such determination e.g. via communication with server 3 via communication path 34. Further, server 3 may perform step 605 by determining, whether or not the at least one second string of characters is present in database 30.

(42) In a step 607, mobile device 4 outputs corresponding information if at least one second string of characters is present in the database, the distance of which to the first string of characters is below the first predefined threshold. For example, mobile device 4 may display corresponding information via display 41. Alternatively, server 3 may perform step 607 by outputting corresponding information to mobile device 4 via communication path 34 to be displayed by mobile device 4 via display 41.

(43) FIG. 7A is a first part of a flow chart illustrating a further exemplary method 700 according to an exemplary embodiment of the invention and FIG. 7B illustrates the second part of method 700.

(44) Without limiting the scope of the invention, it is assumed in the following that steps 711 to 718 of method 700 are exemplary steps of a registration process that may be carried out by a registration device 2 as an example of an apparatus according to the first aspect. Further, steps 721 to 727 are steps of a verification process that may be performed by mobile device 4 as an example of an apparatus according to the second aspect in communication with server 3. It is noted, however, that steps 721 to 727 may be performed e.g. by a dedicated verification device (e.g. installed at an airport) with its own database or in communication with a database such as a network based database.

(45) Turning to FIG. 7A, in step 711, registration device 2 acquires an image of a part of a surface of a passport A, i.e. a passport to be registered. In a step 712 (which may be performed before, after or simultaneously with step 711), registration device 2 obtains identification information of passport A, e.g. by automatically reading text and/or image information from passport A and/or via user input. Identification information may correspond to a serial number of passport A and/or to personal information relating to the passport holder. In step 713, registration device 2 may perform steps of improving the obtained image, in particular may correct the obtained image for size and/or angle and/or may apply at least one (software based) filter to the image.

(46) Based on the image, the registration device 2 generates in step 714 a two dimensional matrix, each entry of the matrix corresponding a perceived height of a corresponding section of the part of the surface of passport A. It is noted that the method may be further improved in terms of robustness if steps 711 to 714 are applied to more than one part of a surface of the passport. For example, the steps 711 to 714 may be applied to different parts of the surface, the position of which is identifiable for corresponding steps applied in a later verification process such as surfaces with a predefined extension with respect to two or more edges of the passport. In addition or alternatively, for each or at least one of such two or more parts of the surface to which steps 711 to 714 are applied, for example different resolutions and/or different sizes of the two dimensional matrix may be applied to introduce further redundancy.

(47) In steps 715 to 717, registration device 2 generates a first, a second and a third portion of a string of characters based on the generated matrix as disclosed in detail above. In step 718, registration device 2 stores the string of characters in association with the obtained identification information in a database, e.g. in database 30 via communication with server 3 and/or in a database comprised by registration device 2.

(48) Turning to FIG. 7B and thus to a verification process of verifying a passport B (which may correspond to passport A or which may be a different passport not registered or registered at a different registration stage), for example performed by mobile device 4, in a step 721 mobile device 4 performs steps 711 to 716 and/or 717 for passport B to generate a first string of characters and to obtain corresponding identification information (a serial number and/or personal information of a holder) of passport B.

(49) In step 722, mobile device 4 determines if the first string of characters obtained for passport B is present in a database. For example, mobile device 4 may communicate with server 3 via communication path 34 and may cause server 3 to determine if the first string of characters obtained for passport B is present in database 30. If the first string of characters is determined to be present in database 30, mobile device 4 outputs corresponding information, e.g. as a corresponding message displayed on display 41 in step 723.

(50) If the first string of characters obtained for passport B is determined to be not present in database 30, mobile device 4 generates (or causes server 3 to generate, this optionally being implicit in step 722) t first model strings of characters being variants of the first string of characters in step 724. For example, 10 first model strings of characters may be generated, each model string of characters representing respective heights of the part of the surface as perceived under a different lighting condition.

(51) In a step 725, mobile device 4 obtains (or causes server 3 to obtain, this optionally being implicit in step 722) u second strings of characters present in the database, e.g. in database 30 that are similar to any one of the t first model string of characters and/or the first string of characters. For example, 7 second strings of characters may be found in database 30, a distance of which to the first string of characters (as described above) is below a predetermined threshold (an example of a first or second threshold as referred to herein).

(52) In a step 726, mobile device 4 generates (or causes server 3 to generate, this optionally being implicit in step 722) v second model strings of characters being variants of the each one of the second model strings of characters. For example 10 second model strings of characters may be generated for each of the 7 second strings of characters.

(53) In a step 727, mobile device 4 determines (or causes server 3 to determine, this optionally being implicit in step 722) whether or not a string of characters is present (among the u second strings of characters and/or the v second model strings of characters) in the database, e.g. in database 30, a distance of which to the first and/or the first model string is below a predefined threshold. For example, the first model string of characters and the 10 first model string of characters (11 strings of characters) may be compared to the second strings of characters and the respective corresponding second model strings of characters (77 strings of characters) to determine if a pair (one of the 11 strings of characters and one of the 77 strings of characters) of strings of characters is present in the database with a distance below a predefined threshold (the fourth threshold disclosed herein). In the affirmative case, mobile device 4 may output corresponding information e.g. via display 41 e.g. confirming that a match is found (e.g. “passport confirmed”) and/or corresponding information, e.g. a serial number of passport B and/or corresponding personal information (e.g. a name) of the holder of passport B to be verified by a user of mobile device 4. In the non-affirmative case in which no match is found (no pair of strings of characters, a mutual distance of which is below the predefined threshold), mobile device 4 may output corresponding non-affirmative information via display 41 (e.g. “passport not confirmed”).

(54) The following example embodiments of the invention are also disclosed:

Embodiment 1

(55) A method performed by at least one first apparatus, the method comprising: obtaining or causing obtaining an image of at least a part of a surface of a document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating a string of characters based on the representation of the at least a part of the surface, the string of characters comprising at least a first portion representative of the set of height levels of the corresponding sections of the at least a part of the surface and a second portion generated based on a function of the representation and/or of the first portion of the string of characters; associating or causing associating information representing the string of characters with identification information of the document.

Embodiment 2

(56) The method according to embodiment 1, further comprising: obtaining or causing obtaining the identification information of the document from the document and/or via user input.

Embodiment 3

(57) The method according to any of embodiments 1 to 2, wherein obtaining an image of at least a part of the surface of the document comprises: obtaining or causing obtaining the image via a digital camera or scanner comprised by or connected to the at least one first apparatus.

Embodiment 4

(58) The method according to any of embodiments 1 to 3, wherein the height levels of the sections are representative of a microstructure of the surface of the document.

Embodiment 5

(59) The method according to any of embodiments 1 to 4, wherein deriving the representation corresponds to or comprises: converting or causing converting the image into a two-dimensional matrix, where each dimension of the matrix corresponds to a spatial dimension of the image (and/or document) and wherein each entry of the matrix is a value representing a height of a corresponding section of the image.

Embodiment 6

(60) The method according to any of embodiments 1 to 5, wherein associating the information representing the string of characters with the identification information comprises at least one of the following: storing or causing storing the information representing the string of characters with the identification information of the document providing or causing providing the information representing the string of characters in association with the identification information of the document to be accessible by at least one external apparatus, in particular via a communication path.

Embodiment 7

(61) The method according to any of embodiments 1 to 6, wherein the at least one first apparatus corresponds to or is comprised by a dedicated device comprising and/or connected to a digital camera and/or scanner.

Embodiment 8

(62) The method according to any of embodiments 1 to 7, wherein the at least one first apparatus corresponds to or is comprised by a mobile device.

Embodiment 9

(63) The method according to any of embodiments 1 to 8, wherein the database is comprised by the at least one first apparatus and/or is connected to the at least one first apparatus via a communication path.

Embodiment 10

(64) A method performed by at least one second apparatus, the method comprising: obtaining or causing obtaining first information representing a first string of characters with a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of a first document; determining or causing determining, based on the obtained first information, whether or not the first string of characters is present in a database; if the first string of characters is not present in the database: determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the first string of characters is below a first predefined threshold; and outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the first string of characters is below the first predefined threshold.

Embodiment 11

(65) The method according to embodiment 10, wherein determining, based on the obtained first information, whether or not the first string of characters is present in a database comprises: determining or causing determining, based on the obtained first information, whether or not the first string of characters is present in a database via communication with an external network device, in particular one or more servers and/or a server cloud, comprising or connected to the database.

Embodiment 12

(66) The method according to any of embodiments 10 to 11, wherein determining, based on the obtained first information, whether or not the first string of characters is present in a database comprises: determining or causing determining, based on the obtained first information, whether or not the first string of characters is stored in the database in association with identification information of the first document.

Embodiment 13

(67) The method according to any of embodiments 10 to 12 further comprising: obtaining or causing obtaining the identification information of the first document from the document, in particular via a camera and/or the scanner comprised by the at least one second apparatus and/or via user input.

Embodiment 14

(68) The method according to any of embodiments 10 to 13, wherein the database is comprised by the at least one second apparatus and/or is connected to the at least one second apparatus via a communication path.

Embodiment 15

(69) The method according to any of embodiment 1 to 14, wherein the database is a storage accessible via the communication path, in particular a storage comprised by or connected to a network server and/or a network server cloud.

Embodiment 16

(70) The method according to any of embodiment 10 to 15, wherein if it is determined that the first string of characters (and/or information thereof) is present in the database, the method further comprises: determining or causing determining a document associated with the first string of characters in the database, the document in particular being stored in the database in association with the first string of characters, as corresponding to the first document.

Embodiment 17

(71) The method according to any of embodiment 1 to 16, wherein, if it is determined that the first string of characters (and/or information thereof) is present in the database, the method further comprises: outputting or causing outputting identification information of the document associated with the first string of characters in the database (e.g. stored in the database in association with the first string of characters).

Embodiment 18

(72) The method according to any of embodiments 10 to 17, further comprising: if the first string of characters is not present in the database, the method further comprises the following steps (a), (b), and (c):

(73) (a) obtaining or causing obtaining at least second information representing at least one first model string of characters with a first portion representative of a first model set of height levels of the corresponding sections of the at least a part of the surface of the first document;

(74) (b) determining or causing determining, based on a metric function, whether or not at least one second string of characters is present in the database, a distance of which to the at least one first model string of characters and/or the first string of characters is below a second predefined threshold;

(75) (c) outputting or causing outputting corresponding information if at least one second string of characters is present in the database, the distance of which to the at least one first model string of characters and/or the first string of characters is below the second predefined threshold.

Embodiment 19

(76) The method according to any of embodiments 10 to 18, wherein the second predefined threshold corresponds to (and/or is equal to) the first predefined threshold.

Embodiment 20

(77) The method according to any of embodiments 10 to 19, further comprising: if at least one second string of characters is determined to be present in the database, the at least one second string of characters comprising a first portion representative of a set of height levels of corresponding sections of at least a part of a surface of at least one respective second document corresponding to the at least one second string of characters and the distance of which to the first string of characters and/or to the at least one first model string of characters is below a third predefined threshold, the method further comprises the following steps (a), (b) and (c):

(78) (a) obtaining or causing obtaining, for each one of the at least one second string of characters, at least third information representing at least one respective second model string of characters corresponding to the at least one second string of characters with a first portion being representative of a second model set of height levels of corresponding sections of at least a part of the surface of the respective second document corresponding to the at least one second string of characters;

(79) (b) determining or causing determining whether or not at least one string of characters of the at least one second string of characters and the at least one corresponding second model string of characters is present in the database for which a distance to any one of the first string of characters and/or the at least one first model string of characters is below a fourth predefined threshold; and

(80) (c) if at least one string of characters of the at least one second string of characters is found, the distance of which to any one of the first string of characters and/or the at least one first model string of characters is below the fourth predefined threshold, outputting or causing outputting corresponding (affirmative) information.

Embodiment 21

(81) The method according to embodiment 20, wherein the information outputted is affirmative information, e.g. “document accepted”, or corresponds to the identification information of the second document, e.g. a serial number of the second document, in particular to be confirmed by a user of the at least one second apparatus.

Embodiment 22

(82) The method according to any of embodiments 20 to 21, if no string of characters of the at least one second string of characters is found, the distance of which to any one of the first string of characters and/or the at least one first model string of characters is below the fourth predefined threshold the method comprise a step (d) of: outputting or causing outputting corresponding non-affirmative information, e.g. “document not accepted”.

Embodiment 23

(83) The method according to any of embodiments 20 to 22, wherein the third predefined threshold corresponds to (and/or is equal to) the second predefined threshold and/or the first predefined threshold.

Embodiment 24

(84) The method according to any of embodiments 10 to 23, wherein for each one of the at least one first model string of characters, the first model set of height levels of the corresponding sections of the at least a part of the surface of the first document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions; and/or wherein for each one of the at least one second model string of characters, the second model set of height levels of the corresponding sections of the at least a part of the surface of the second document is obtained by calculating the height levels of the corresponding sections assuming different lighting conditions.

Embodiment 25

(85) The method according to any of embodiments 10 to 24, wherein the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters each comprise respective second portions; and wherein respective mutual distances between the first string of characters, the at least one second string of characters, the at least one first model string of characters and the at least one second model string of characters are determined based on the metric function and based on the respective second portions.

Embodiment 26

(86) The method according to any of embodiments 10 to 25, wherein obtaining the first information comprises: obtaining or causing obtaining an image of at least a part of a surface of the document; deriving or causing deriving a representation of the at least a part of the surface from the image, the representation comprising a set of values respectively representing a corresponding set of height levels of corresponding sections of the at least a part of the surface; generating or causing generating the first string of characters based on the representation of the at least a part of the surface; or receiving or causing receiving the first information via a network connection.

Embodiment 27

(87) The method according to embodiment 26, wherein a second portion of the first string of characters is generated based on a function of the representation and/or of the first portion of the first string of characters.

Embodiment 28

(88) The method according to any of embodiments 1 to 27, wherein obtaining the image comprises obtaining the image using a digital camera or a scanner.

Embodiment 29

(89) The method according to embodiment 28, wherein obtaining the image of the at least a part of the surface comprises: applying or causing applying ultraviolet, UV, infrared, IR, and/or white light to the at least a part of the surface.

Embodiment 30

(90) The method according to any of embodiments 1 to 29, wherein the string of characters, the first string of characters, the second string of characters, the at least one first model string of characters, and/or the second model string of characters further comprises a third portion different from the first and/or the second portion and being determined based on a hash function of the first portion and/or the second portion and/or comprising a checksum of the first portion and/or the second portion.

Embodiment 31

(91) The method according to any of embodiments 1 to 30, wherein a mobile device corresponds to and/or is comprised by an Internet-of-Things (IoT) device, a smartphone, a tablet computer, a notebook computer, a smart watch, and a smart band.

Embodiment 32

(92) The method according to any of embodiments 1 to 31, wherein the height levels represent a microstructure of the at least part of the surface.

Embodiment 33

(93) The method according to any of embodiments 1 to 32, wherein the document, the first document and/or the second document corresponds to at least one of an official document, an official identification document, and/or a government-issued document and/or card.

Embodiment 34

(94) The method according to any of embodiments 1 to 33, wherein a communication path corresponds to and/or comprises a (bi-directional) wireless and/or wired network connection, in particular a wireless network connection that enables a network entity to transmit and receive data via said connection.

Embodiment 35

(95) The method according to embodiment 34, wherein a wireless connection comprises a wireless communication path or link in a wireless communication network, in particular a terrestrial wireless communication network like a Wireless Local Area Network (WLAN) or a cellular network, wherein WLAN is for example specified by the standards of the IEEE 802.11 family (http://www.ieee.org/) and wherein a cellular network may for example be a mobile phone network like a 2G/3G/4G/5G cellular communication network, the 2G/3G/4G/5G cellular radio communication standards being developed by the 3GPP and being available under http://www.3gpp.org/, wherein a wireless connection may further comprise a Device-to-Device (D2D) communication path.

Embodiment 36

(96) An apparatus comprising at least one processor and at least one memory that contains program code, wherein the memory and the program code are configured to use the at least one processor to cause an apparatus to perform and/or control at least the method of any of embodiment 1 or 10.

Embodiment 37

(97) An apparatus comprising at least one processor and at least one memory that contains program code, wherein the memory and the program code are configured to use the at least one processor to cause an apparatus to perform and/or control at least the method of any of embodiments 11 to 36.

Embodiment 38

(98) System comprising at least one first apparatus configured to perform the method according to any of embodiments 1 or 10 and at least one second apparatus configured to perform the method according to any of embodiments 11 to 36.

(99) In the specification, any presented connection in the described embodiments is to be understood in a way that the involved components are operationally coupled. Thus, the connections can be direct or indirect with any number or combination of intervening elements, and there may be merely a functional relationship between the components.

(100) Moreover, any of the methods, processes and actions described or illustrated herein may be implemented using executable instructions in a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, or the like) to be executed by such a processor. References to a ‘computer-readable storage medium’ should be understood to encompass specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices.

(101) The expression “A and/or B” is considered to comprise any one of the following three scenarios: (i) A, (ii) B, (iii) A and B. Furthermore, the article “a” is not to be understood as “one”, i.e. use of the expression “an element” does not preclude that also further elements are present. The term “comprising” is to be understood in an open sense, i.e. in a way that an object that “comprises an element A” may also comprise further elements in addition to element A.

(102) It will be understood that all presented embodiments are only exemplary, and that any feature presented for a particular example embodiment may be used with any aspect of the invention on its own or in combination with any feature presented for the same or another particular example embodiment and/or in combination with any other feature not mentioned. In particular, the example embodiments presented in this specification shall also be understood to be disclosed in all possible combinations with each other, as far as it is technically reasonable and the example embodiments are not alternatives with respect to each other. It will further be understood that any feature presented for an example embodiment in a particular category (method/apparatus/computer program) may also be used in a corresponding manner in an example embodiment of any other category. It should also be understood that presence of a feature in the presented example embodiments shall not necessarily mean that this feature forms an essential feature of the invention and cannot be omitted or substituted.

(103) The sequence of all method steps presented above is not mandatory, also alternative sequences may be possible. Nevertheless, the specific sequence of method steps exemplarily shown in the figures shall be considered as one possible sequence of method steps for the respective embodiment described by the respective figure.

(104) The invention has been described above by means of example embodiments. It should be noted that there are alternative ways and variations which are obvious to a skilled person in the art and can be implemented without deviating from the scope of the appended claims.