Device to perform inline integrity verification of a security feature on an identification document

Abstract

The present invention relates to a method and a device to perform inline integrity verification of a security feature (101) on an identification document (102), the device (100) comprising: an illumination unit (104) for illuminating the security feature (101) on the identification document (102); - an image capturing unit (108) for acquiring an image (124) of at least a region of the illuminated security feature (101) on the identification document (102); and - a processing unit (116) for processing and verifying the security feature (101) on the identification document (102) based on the acquired image (124); wherein the illumination unit (104) comprises an IR-light source (106) for illuminating the security feature (101) on the identification document (102) with IR light.

Description

[0001] Device to perform inline integrity verification of a security feature on an identification document

[0002] The present invention relates to a device and a method for verifying a security feature on an identification document as well as to an automatic inspection unit comprising a device for verifying an identification document.

[0003] Common security features of identification documents such as passports are images or photos of the holder of the passport, i.e. an image of the face of a person on the passport. These images can be placed on the identification document on a metallic surface that has a microscopic periodic structure that results in an angle dependent highly reflective surface. The metallic surface can be placed inside the document during the lamination of the polycarbonate to generate the data page for passport or the ID cards. The image is laser engraved and has color information. There might be angle dependent features on the document, especially a diffractive optically variable image device (DOVID). Further, there may be a grid on these angle dependent images.

[0004] After the personalization of the identification document, it is desired to check whether the right image was printed on the right document. This is done by shape matching of the person in both the reference image in the database and the acquired image on the produced identification document like a passport taken by a camera.

[0005] Only at a certain angle between incident light and the observer one can see the true colors and the right contrast of the image personalized in this patch. Only at that exact angle using visible light one can acquire an image of the document that can be used later for an automatic integrity check in a personalization equipment of identification documents like passports or cards. Because of both the highly reflecting surface and the angle dependent visualization of the personalized image such an implementation of an inline integrity check of the feature in a robust and flexible manner is challenging.

[0006] Furthermore, the security feature on the identification document can have a grid on the surface and this grid disturbs the quality of the image taken. Further, the contrast of the image is sensitive to feature positional floatation within the document and is highly angle dependent and sensitive to hardware misalignment and other factors like for instance external white light illumination / reflections (e.g. light from the ceiling). Also, current approaches are not flexible and need to be adapted to the location of the security patch in the document layout due to the angle dependency of the visualization making some location difficult to implement in an inline inspection in the production machine.

[0007] For shape matching, such images provide low scores making it difficult to differentiate between wrong images, for example look alike cases. This results in a poor shape matching score when comparing the acquired image with the reference image.

[0008] It is therefore an object of the invention to provide a device and a method for verifying an identification document that provide a high-resolution image of the security patch and can be used in automatic inspection units especially in an inline inspection when shape matching the image on the document with the reference image in the database.

[0009] The problem is solved by a device to perform inline integrity verification of a security feature on an identification document according to the independent product claim and a method for performing inline integrity verification of a security feature on an identification document according to the independent method claim.

[0010] The problem is especially solved by a device to perform inline integrity verification of a security feature, preferably a high reflective security feature like an angle dependent photo with color information of the holder on an identification document, the device comprising:

[0011] - an illumination unit for illuminating at least the security feature on the identification document,

[0012] - an image capturing unit for acquiring an image of at least a region of the illuminated security feature on the identification document and

[0013] - a processing unit for processing and verifying the security feature on the identification document based on the acquired image wherein the illumination unit comprises an I R-light source for illuminating the desired region of the security feature on the identification document with IR light.

[0014] A device to perform inline integrity verification is a device which is configured to automatically check the correct producing, i.e. the right placement of the right image on the respective identification document, of a security feature on an identification document during the process of personalizing the identification document. This device is preferably configured to be used inline in the production process of a security feature on an identification document. Thus, the device can be a station in the inline process of producing and verifying the correct production and placement of a security feature on an identification document.

[0015] The security feature is preferably a personalizable high reflective security feature like an angle dependent photo with color information of the holder. These security features, for instance a photo of the holder of the passport, are preferably placed on the identification document on a metallic surface that has a microscopic periodic structure that results in an angle dependent highly reflective surface. Preferably, a RGB matrix is treated by a laser to engrave dots in the specific RGB areas or to ablate material from there thus determining the color of a specific dot. Thus, the feature like for instance the image is preferably laser engraved and / or ablated by a laser and has color information. Preferably, there are angle dependent features on the document, especially a diffractive optically variable image device (DOVID). Most preferably, an image is laser engraved with color information further making use of the DOVID technology, i.e. it comprises for instance a color portrait embedded in a DOVID. Further, there is preferably a grid on these angle dependent images.

[0016] An identification document (ID) is a token which serves to identify the owner. An ID is any document that may be used to prove a person’s identity. Preferably, an identification document is an identity card (IC, ID card, citizen card) or a passport card. Sometimes, a driving license my serve as an identification document to prove a person’s identity. Further, it can be an ID access pass.

[0017] An illumination unit for illuminating at least the security feature or parts of the security feature on the identification document is a part of the device to illuminate at least certain areas of the ID and especially the security feature on the ID. It is preferably also possible to illuminate an area larger than the ID. The illumination device preferably comprises a light source. The light source may comprise light sources in the UV, VIS, NIR, IR, and THz spectral regions or a combination of these light sources and does at least and most preferably comprise an IR-light source for illuminating the security feature on the identification document with IR light.

[0018] Further, the illumination unit preferably comprise optical elements to guide the light from the light source to the desired area. Such optical elements preferably comprise mirrors, filters, polarizers, scanners, beam displacement optics like a tweaker plate, prisms, diffraction gratings, diffusers, lenses or a (sub-)combination thereof.

[0019] The image capturing unit for acquiring an image of at least a region of the illuminated security feature on the identification document is the part of the device which takes a picture of the security feature, for instance a picture of the photo on the passport. Preferably, the at least one region of the document is the region in which a security feature is located. It is preferably also possible to capture the whole ID or even an area larger than the ID. Thus, a broader area for placing the ID can be used and the requirement for alignment of the ID is not as strict. The image capturing unit preferably comprises a camera. Further, the image capturing unit preferably comprises optical elements to guide the light from the security feature to the camera. Such optical elements preferably comprise mirrors, filters, polarizers, scanners, beam displacement optics like a tweaker plate, prisms, diffraction gratings, diffusers, lenses or a (sub-)combination thereof.

[0020] The processing unit preferably comprises a processor and a graphic card. Preferably, the processing unit comprises a computer. The processing unit is adapted to process the information gathered by the image capturing unit, preferably the image information of the acquired image. The processing unit preferably comprises a negative-positive converter application, a color inverter application, a brightness adjustment application, a contrast adjustment application or a combination thereof. Further, the processing unit preferably comprises a storing unit for storing the data associated with the acquired image as well as the data of the enhanced acquired image, i.e. the image when processed by the processing unit originating from the acquired image.

[0021] With the capturing of the image of the security feature on the ID and the processing of the acquired image, artefacts in the enhanced acquired image are reduced.

[0022] Further, the processing unit is adapted to verify the security feature on the identification document based on the acquired image. The main purpose of this verification or inspection is to (a) check whether it is the right person or the right logo or text or numbers or a picture or a combination thereof on the ID and (b) whether the quality of the engraved image is above a certain threshold. Preferably, this is accomplished by a comparison of the enhanced acquired image with the original image which was the basis for the security feature in the first place, for instance, a comparison of the image as acquired with a reference image in the database which was intended to be placed on the identification document. Preferably, the comparison comprises a shape matching of the person or the logo. Most preferably, the processing unit derives parameters of both images (the enhanced acquired image and the reference image) and compares these parameters. If there is a match, i.e. for a certain percentage above a predefined threshold a number of parameters can be found in both images, the processing unit gives the result that the images are identical and the security feature on the ID is verified. Further, the threshold can be set to identify whether the acquired image is not blurred too much, only can be seen in parts (less than 20% of the image), etc. In case this threshold is not met, the processing unit gives the result that the images are not identical and the security feature on the ID is not verified.

[0023] With the I R-light source for illuminating the security feature on the identification document with IR light, the captured image loses the color information. Further, since the engraving of the RGB pattern creates holes in these areas, the IR illumination helps to get a more reliable image which is not angle dependent. By using IR light for illumination, only the parts engraved in the metallized patch of the at least one region reflects the IR light which improves the quality of the acquired image and the image acquisition. Thus, this technique allows a more reliable handling of the processing unit when verifying the security feature on the identification document based on the acquired image, especially when shape matching since the lines forming the image have a large amount of spaces resulting in a less reliable verification.

[0024] According to an embodiment, the I R-light source is a darkfield illumination I R-light source. The darkfield illumination I R-light source further improves the reflection of the light at the above-mentioned engraved parts of the identification document and therefore increases the quality of the acquired image and further reduces artefacts in the acquired image which further improves the verification of the document.

[0025] In an embodiment, the image capturing unit comprises a camera and at least one lens to acquire the image, wherein the camera comprises a field of view of the whole identification document. This embodiment also increases the quality of the acquired image. In addition, due to the IR light and the field of view of the camera the image to be acquired can be placed everywhere on the identification document without the risk of losing quality. In addition, or alternatively, the camera and the at least one lens are configured to filter out other security elements placed on top of the security features, such as embossing or tactile features and others, and artifacts, such as a grid, of the at least one region of the identification document. To filter out these other security elements, the camera and the at least one lens preferably comprise a spatial resolution which is lower than the other security element. Especially, the optical system has a lower resolution to avoid capturing a grid on these angle dependent images. The camera and lens combination preferably has a spatial density, that is an amount of pixels per millimeter in the field of view, of around one time or less than the size of the smallest dimension of the grid (or named other security elements). Thus, the other security element can be filtered out by the optical arrangement and is not present on the acquired image.

[0026] According to a further embodiment, the image capturing unit is configured to acquire the image independently of the angle of view to the identification document. Since the image was produced on the ID by making holes in the metallic surface, the image capturing unit preferably employs means in which uneven structures on the metallic surfaces are enhanced and thus made more easily visible, for instance by IR darkfield technology. Due to this embodiment, the acquisition of the image is no longer angle dependent. Hence, the acquisition of the image is further independent from the position of the image. Such an implementation enables the use of the device with an inline inspection.

[0027] The acquired image may however be a negative image. Therefore, the processing unit is configured to process and thus enhance the acquired image by using at least one of the following: color inversion; and / or negative-positive conversion brightness adjustment; and / or contrast adjustment.

[0028] The security feature can be a portrait of a person as known from passports. Alternatively, it can be a graphical sign, like the logo of a company, or text or numbers or a picture or a (sub-)combination thereof. In an embodiment, the processing unit for verifying the identification document is configured to compare the enhanced acquired image with a reference image of the identification document.

[0029] The method for verifying a security feature on an identification document comprises the following steps: illuminating at least parts of the identification document with I R-light via an illumination unit; acquiring an image of at least a region of the illuminated identification document via an image capturing unit; and optionally enhancing the acquired image by processing the acquired image and verifying the security feature on the identification document based on the acquired image, especially the enhanced acquired image, via a processing unit by comparing the enhanced acquired image with a reference image.

[0030] By illuminating the identification document with I R-light via an illumination unit and then acquiring an image of at least a region of the illuminated identification document, the color information of the security feature is lost and the acquired image has only black and white and grey information. Thus, the quality of the contrast of the acquired image is higher than with this color information.

[0031] By processing and verifying the security feature of the identification document based on the acquired image via a processing unit it can be verified that the right information, that includes images, logo, text or number, is personalized in the security feature on the correct ID. The verification is preferably carried out by a comparison of the acquired image and a reference image. Preferably, the comparison is carried out between an enhanced acquired image which is processed by one or more steps to improve quality of the acquired image and the reference image. Thus, the enhancing step is preferred. The reference image is the original image which was used to produce the security feature. It is preferably stored in the processor of the production device or in a database.

[0032] The processing steps can use the means as described in context with the product.

[0033] Preferably, the method is executed by the device for verifying an identification document as mentioned before. According to an embodiment, the method further comprises the step: acquiring the image independently of the angle of view to the identification document.

[0034] This can for instance be accomplished by capturing an image with IR technology. Especially with darkfield IR light, only angle independent surfaces of the document return information. This can for instance be the holes of the metallic surface - the larger the hole is, the brighter the information in the captured image and the dark parts of the acquired image correspond to intact metallic surface or DOVID or RGB matrix as that reflection is not captured by the camera due to the use of the darkfield. Thus, no reflective surfaces have a negative impact and the ID can more freely be positioned when capturing the acquired image and allows for the security feature to be present anywhere in the document without the need to adapt or realign the device. Thus, a robust system to different document layouts insensible to misalignments is provided.

[0035] In a further embodiment, the method additionally comprises the step: processing the acquired image by using at least one of the following: inverting the colors; and / or converting negative to positive and vice versa; and / or adjusting the brightness; and / or adjusting the contrast.

[0036] With these different processing applications, the quality of the acquired image can be enhanced and the result more reliably compared to the refence image.

[0037] In addition, an automatic inspection unit is also disclosed and claimed by the present invention. The automatic inspection unit comprises a device for verifying an identification document as mentioned before, especially inline during the personalization process of the ID.

[0038] Further preferred features and / or advantages of the invention are subject matter of the following description of the figures: Fig. 1 a schematic illustration of a device for verifying an identification document according to the invention; and

[0039] Fig. 2 a schematic comparison between the processed image according to the prior art and according to the invention.

[0040] In the figures, identical components are always shown with the same reference signs.

[0041] Fig. 1 shows a schematic illustration of a device 100 for verifying an identification document 102 with a security feature 101. The security feature 101 is schematically shown on the identification document 102 in a higher level to better illustrate. The security feature 101 preferable is embedded in the level of the identification document 102. Preferably, both the security feature 101 and the identification document 102 have a lamination cover (not shown).

[0042] The device 100 comprises an illumination unit 104 for illuminating the identification document 102. The identification document 102 can be a passport, a driver's license or any other ID card or access granting card. On the identification document 102 is a security feature 101 in the form of a photo of a person.

[0043] The illumination unit 104 comprises an I R-light source 106 for illuminating the identification document with IR light LIR. Preferably, the I R-light source 106 is a darkfield illumination IR- light source.

[0044] In addition, the device 100 comprises an image capturing unit 108 for acquiring an image of at least a region of the illuminated identification document 102.

[0045] The image capturing unit 108 comprises a camera 110 and at least one lens 112 to acquire the image. The camera 110 comprises a field of view 114 of the whole identification document 102.

[0046] Moreover, the device 100 comprises a processing unit 116 for processing and verifying the identification document 102 based on the acquired image.

[0047] For verifying the identification document 102, the processing unit 116 is connected to the image capturing unit 108 to receive the acquired image from the image capturing unit 108. After that the processing unit 116 enhances the acquired image. This is described in more detail with regard to Fig. 2 in the following. Afterwards, the enhanced acquired image is compared to a reference image and it is decided whether the acquired image and the reference image is a match.

[0048] The aforementioned device 100 can be part of an automatic inspection unit 118 for an inline inspection. Such inspection units 118 can be a station in the device for personalizing the ID by printing the security feature 101 on the identification document 102.

[0049] With regard to Fig. 2, a comparison between the verification of a security feature 101 on an identification document 102 based on an image verification according to the prior art and according to the invention is shown.

[0050] On the left side, a reference image 120 is shown. The upper line shows an acquired image 122 captured with white light according to known techniques. As can be seen from the image 122 that the quality is not that good. A comparison with the reference image 120 is difficult, especially if the comparison should be automatically, which means that the comparison and the verification is not made by e.g. a human worker.

[0051] As can be seen from the lower line, the first shown image is an acquired image 124 captured by the image capturing unit 108 and with IR light LIR.

[0052] Although the acquired image 124 is a negative image, the quality is much better than the acquired image 122 according to the prior art.

[0053] Since the acquired image 124 is a negative, the processing unit 116 in a first step 126 inverts the colors of the acquired image 124 or when it is a black and white picture it converts negative to positive and vice versa. This results in an enhanced acquired image with inverted colors and / or negative / positive conversion. After that as a second step 128 the processing unit continues the enhancement by adjusting the brightness and / or the contrast of the acquired image 124. This results in an enhanced acquired image with adjusted brightness and / or contrast.

[0054] After this enhancement, the acquired image 124 is ready for the verification process, namely, for the comparison of the enhanced acquired image with inverted colors and / or negative / positive conversion and / or with adjusted brightness and / or adjusted contrast with the reference image 120.

[0055] To sum it up, the present invention offers the following advantages:

[0056] - removing of the angle dependency of the image acquisitions; making it possible to reuse hardware set-ups for different positions of a security feature in or on a document;

[0057] - improving the overall contrast of the acquired image;

[0058] - improving the quality of the acquired image and of the data personalized in the security sign as security elements and artefacts can be filtered out; and

[0059] - provide a robust, efficient and high-quality inline inspection unit.

[0060] List of reference signs

[0061] 100 device to perform inline integrity verification

[0062] 101 security feature

[0063] 102 identification document ID

[0064] 104 illumination unit

[0065] 106 IR-light source

[0066] 108 image capturing unit

[0067] 110 camera

[0068] 112 lens

[0069] 114 field of view of the camera

[0070] 116 processing unit

[0071] 118 automatic inspection unit

[0072] 120 reference image

[0073] 122 acquired image with white light

[0074] 124 acquired image with IR light

[0075] 126 enhanced acquired image with inverted colors and / or negative / positive conversion

[0076] 128 enhanced acquired image with adjusted brightness and / or contrast

[0077] L|R IR light

Claims

Claims1. Device (100) to perform inline integrity verification of a security feature (101) on an identification document (102), the device (100) comprising: an illumination unit (104) for illuminating the security feature (101) on the identification document (102); an image capturing unit (108) for acquiring an image (124) of at least a region of the illuminated security feature (101) on the identification document (102); and a processing unit (116) for processing and verifying the security feature (101) on the identification document (102) based on the acquired image (124); wherein the illumination unit (104) comprises an IR-light source (106) for illuminating the security feature (101) on the identification document (102) with IR light.

2. Device (100) according to claim 1 , wherein the IR-light source (106) is a darkfield illumination IR-light source.

3. Device (100) according to claim 1 or 2, wherein the image capturing unit (108) comprises a camera (110) and at least one lens (112) to acquire the image (124), wherein the camera (110) comprises a field of view of the whole identification document (102).

4. Device (100) according to claim 3, wherein the camera (110) and the at least one lens (112) are configured to filter out security elements and / or artefacts on the at least one region of the identification document (102).

5. Device (100) according to any one of claims 1 to 4, wherein the image capturing unit (108) is configured to acquire the image (124) independently of the angle of view to the identification document (102).

6. Device (100) according to any one of claims 1 to 5, wherein the processing unit (116) is configured to process the acquired image (124) by using at least one of the following: color inversion; and / or negative-positive conversion; and / or brightness adjustment; and / or contrast adjustment.

7. Device (100) according to any one of the preceding claims, wherein the processing unit (116) for verifying the identification document (102) is configured to compare a reference image (120) with the acquired image (124) of the security feature (101) on the identification document (102).

8. Device (100) according to any one of the preceding claims, wherein the identification document (102) is at least one of the following documents: passport driver’s license; and / or ID access pass.

9. Method for verifying a security feature (101) on an identification document (102), the method comprising the steps: illuminating at least parts of the identification document (102) with I R-light via an illumination unit (104); acquiring an image (124) of at least a region of the illuminated identification document (102) via an image capturing unit (108); and optionally enhancing the acquired image (124) by processing the acquired image (124) and verifying the security feature (101) on the identification document (102) based on the acquired image (124), especially the enhanced acquired image (126, 128) via a processing unit (116) by comparing the acquired image (124, 126, 128) with a reference image (120).

10. Method according to claim 9, further comprising the step: acquiring the image (124) independently of the angle of view to the identification document (102).

11. Method according to claim 9 or 10, further comprising the step: processing the acquired image (124) by using at least one of the following: inverting the colors; and / or converting negative to positive and vice versa; and / or adjusting the brightness; and / or adjusting the contrast.

12. Automatic inspection unit comprising a device (100) according to any one of claims 1 to 8.

Images