EP2754137B1 - Device to recognise in a mobile way a document - Google Patents

Description

The present invention relates to the field of document recognition.

Modern documents, such as identification documents, driver's licenses, motor vehicle letters, banknotes or other documents, are usually provided with optically detectable security features, which allow a document to authenticate a document. For document recognition such security features are optically recorded and evaluated. Currently, however, such checks are usually only stationary using complex detection devices, which are available only to a limited group of users possible.

The publication EP 1 672 568 A1 shows a system for validating an item, for example a banknote.

The publication FR 2 801 125 A1 shows a method for recognizing a document, wherein the document comprises materials that emit a characteristic wavelength spectrum when excited by light.

The publication US 2005/100204 A1 shows a system for detecting security features of a document.

The publication WO 95/19019 A2 shows a system for the detection of banknote counterfeiting.

The publication WO 2009/158324 A1 shows a system for detecting an authenticity of an object.

It is therefore the object of the present invention to provide a document recognition concept that enables in particular a mobile document recognition.

This object is solved by the features of the independent claims. Advantageous forms of further development are the subject of the dependent claims, the description and the attached figures.

The present invention is based on the finding that security features that have wavelength conversion properties can be excited using a LED light (LED: Light Emitting Device) for the purpose of document recognition. In response to this excitation, such a security feature emits light having a wavelength spectrum different from a wavelength spectrum of the exciting LED light. This difference can be recorded and evaluated for document recognition.

A security feature exhibiting wavelength conversion properties may include, for example, siliceous pigments, especially silicate phosphorous pigments, silicate, sulfide, nitride, YAG, TAG, thiogallate phosphorous pigments added to a printing ink. Such a security feature emits a color-shifted light spectrum responsive to blue light excitation at the wavelength of about 400 nm, which may include, for example, green, yellow, orange, and / or red light.

To excite such a security feature, it is therefore possible to use an LED whose light emission spectrum comprises blue light in a wavelength range between 390 nm and 470 nm. The document recognition can therefore be performed by means of an ordinary smartphone equipped with an LED flash unit.

According to one aspect, the invention relates to a device for detecting a document having a security feature with wavelength conversion properties, with a light generating device, which is designed to illuminate the security feature for emitting light with excitation light, an image pickup device, which is formed by a receive the security feature in response to the excitation light emitted light to obtain an emission recording. The image pickup device is configured to receive light emitted by the security feature in response to a reference light to obtain a reference pickup. The apparatus further includes a processor configured to detect the document based on the emission pickup and the reference pickup.

The processor can be designed to execute a program for document recognition. The program may be stored in executable or compilable form in memory accessible to the processor.

However, the processor can be hard-wired and thus be set up by hardware technology to carry out the document recognition. The hardwiring can be realized for example by means of an application-specific integrated circuit.

The document may be one of the following documents, with or without electronics: identity document such as identity card, passport, access control card, passport, company card or credit card, tax stamp or ticket, birth certificate, driver's license or vehicle pass, banknote, check, postal stamp, or other means of payment For example, a bank card or credit card. The document can be single-layered or multi-layered or paper and / or plastic-based. The document may be constructed of plastic-based films which are joined together to form a card body by means of gluing and / or lamination, the films preferably having similar material properties.

The excitation light may comprise or be blue light in a wavelength range from 390 to 470 nm, preferably in a wavelength range between 430 and 460 nm. The For this purpose, the light-generating device can comprise an LED for generating continuous light or flash light or pulsed light.

In response to the excitation with the excitation light, the security feature is excited to emit light. Due to the wavelength conversion properties of the security feature, which can be realized, for example, by the use of a silicate compound, such as silicate phosphor, the security feature emits light having a wavelength that differs from a wavelength of the excitation light. The emission recording thus contains information about a wavelength spectrum emitted by the security feature in response to the excitation light. By analogy, the reference receptacle includes information about a reference wavelength spectrum that is emissive by the security feature in response to the reference light.

The processor can, for example, compare the emission recording with the reference recording in order, for example, to check the authenticity of the document. In this case, at least one wavelength difference or a temporal or a spectral decay behavior of the respective wavelength spectrum, which may comprise a single wavelength or a plurality of wavelengths, be used for comparison.

According to one embodiment, the light generating device is designed to illuminate the document with a predetermined number of light pulses in order to illuminate the security feature with the excitation light. The light pulses can be generated, for example, with a pulse duration and / or with a pulse interval of 0.05 ms to 100 ms, in particular of 0.5 ms to 10 ms. In this case, for example, two, three or more light pulses can be generated.

According to one embodiment, the light-generating device is designed to generate the number of light pulses with a light pulse spacing which lies in a predetermined light pulse distance range. The light pulse distance range may be, for example, between 0.5 ms and 10 ms.

According to one embodiment, the image recording device is designed to record the respective recording within a recording closure time, wherein each light pulse of the number of light pulses may have a time duration that is shorter than the recording closure time. Alternatively, the light generating means may be configured to generate the number of pulses within the shot shutter time.

The recording shutter time is determined, for example, by a shutter system of the image recording device, a so-called shutter. The recording shutter time is the recording shutter time in which the shutter system is open, for example, to apply light to a color image sensor of the image recording device. The absorption time can for example be in the range of 0.05 ms to 100 ms, in particular from 10 ms to 50 ms, in particular at 33 ms.

According to one embodiment, the reference light is white light, in particular daylight. Alternatively or additionally, the light generating device may be configured to generate the reference light. For this purpose, the light generating device can generate continuous light or reference light pulses during the reference recording.

The term "continuous light" denotes a continuous illumination of the security feature during a recording time, for example during the aforementioned recording shutter time within which the respective recording is made.

According to one embodiment, the processor is configured to compare the emission recording with the reference recording in order to obtain a comparison result and to recognize the document on the basis of the comparison result. For example, wavelength differences can be detected by this comparison.

According to an embodiment, the reference light has a predetermined wavelength. The processor is designed to determine a wavelength difference between the predetermined wavelength and at least one wavelength of the emission light or a temporal wavelength profile of the emission light with respect to the predetermined wavelength, in particular a time profile of a wavelength amplitude or wavelength differences, in order to obtain the comparison result.

The temporal wavelength profile of the emission light can be obtained, for example, by a plurality of images. From this, for example, a temporal decay behavior of the emission wavelengths or of the wavelength amplitudes can be compared with a temporal decay behavior of the emitted reference wavelengths or reference wavelength amplitudes. However, the temporal wavelength characteristic may also include the time course of wavelength differences.

According to one embodiment, the processor is configured to compare the comparison result with a prestored comparison reference to detect the document. Alternatively or additionally, the apparatus comprises a transceiver unit which is configured to record the emission recording or the reference recording or a comparison result of a comparison of the emission recording sending the reference record via a communication network to a remote server for the purpose of document recognition, and responsively receiving a result of the document recognition.

For example, the prestored comparison reference may indicate how a comparison should be made between the reference shot and an emission shot of a light emitted by a true or by a fake security feature. If the results of the comparison match, it is thus possible to conclude that the security feature and thus the document are authentic or falsified.

According to one embodiment, the device is a mobile communication device, in particular a smartphone, wherein the light generating device is an LED flash unit of the mobile communication device and wherein the image pickup device is a digital camera of the mobile communication device. The document recognition is thus possible with cheap and mobile communication devices. In this case, it is utilized that, for example, an LED flash of an ordinary smartphone comprises a blue part in the aforesaid wavelength range which provides a silicate connection of a light conversion safety feature, i. Wavelength conversion, can stimulate.

According to one embodiment, the device comprises a control device for activating the light-generating device in order to generate excitation light and / or reference light. The control device can be set up in terms of programming and, for example, be designed to execute a computer program that can be an application software (APP).

According to one embodiment, the device is set up by programming. In this case, the processor is designed to execute a program which implements the features of the processor. The program may be stored in a memory of the device in executable form or in a compilable form.

According to a further aspect, the invention relates to a method for recognizing a document that has a security feature with wavelength conversion properties comprising illuminating the security feature with excitation light, receiving light emitted by the security feature in response to the excitation light to obtain emission capture, receiving light emitted by the security feature in response to a reference light to obtain reference capture, and detecting the document the basis of the emission intake and the reference intake.

The method can be carried out, for example, by means of the aforementioned device. In particular, the step of illuminating the security feature can be carried out by means of the illumination device. The recording steps may be performed by the image pickup device. The step of recognizing the document may be performed by the processor.

Further features of the method result directly from the functionality of the device for recognizing the document or from the functionality of an element of this device.

According to a further aspect, the invention relates to a computer program with a program code for carrying out the method for recognizing a document, when the computer program is executed on a mobile communication device, in particular on a smartphone. For example, the computer program may be implemented as an APP.

According to a further aspect, the invention relates to a program-technically configured device which is designed to execute the computer program with a program code for carrying out the method according to the invention for recognizing a document.

According to a further aspect, the invention relates to a signal sequence, in particular a signal sequence which can be transmitted via a communication network, such as the Internet, which represents data representing the computer program with a program code for carrying out the method according to the invention for recognizing a document.

According to a further aspect, the invention relates to a document of the aforementioned type having a security feature which comprises a printing ink having wavelength-converting pigments, in particular silicate phosphor pigments, silicate, sulfide, nitride, YAG, TAG, thiogallate phosphorous pigments, includes.

Fig. 1

ein Blockdiagramm einer Vorrichtung zum Erkennen eines Dokumentes gemäß einer Ausführungsform; und

Fig. 2

ein Diagramm eines Verfahrens zum Erkennen eines Dokumentes gemäß einer Ausführungsform.

Further embodiments will be explained with reference to the accompanying drawings. Show it:

Fig. 1

a block diagram of a device for recognizing a document according to an embodiment; and

Fig. 2

a diagram of a method for recognizing a document according to an embodiment.

Fig. 1 Fig. 12 shows a block diagram of a document recognition apparatus 100 having a security feature with wavelength conversion characteristics. The device 100 comprises a light-generating device 101, which is used to excite the in Fig. 1 not shown document generates excitation light.

The apparatus 100 further comprises an image pickup device 103, for example a digital camera, which receives the light emitted by the security feature in response to the excitation from the excitation light, thereby obtaining an emission pickup.

The image pickup device 103 is configured to receive light emitted by the security feature in response to a reference light to obtain a reference pickup. The reference light may be, for example, white light, in particular daylight, or continuous light. According to an embodiment, the reference light may be generated by the light generating device 101.

The apparatus 100 further comprises a processor 105, which is provided to detect the document on the basis of the emission recording and the reference recording.

In the Fig. 1 illustrated device 100 may be, for example, a mobile communication device, in particular a smartphone, or a portable computer equipped with a light generating device, such as an LED, and an image pickup device, such as a digital camera. Such communication devices can be set up, for example, by means of software, in particular by means of an APP, for the recognition of documents which have wavelength-converting security features. For this purpose, the existing hardware can advantageously be used unchanged. Because all image acquisition procedures and / or Bildanalysealgorithmen, which as proof of authenticity or authenticity a document can be used in the context of document recognition, can be run on a processor as an APP.

The light generating device can be designed, for example, a flash unit based on an HP LED (High Power Light Emitting Diode) or an HB LED (High Brightness LED). Such LEDs emit light of the color blue in a wavelength range of 390 to 470 nm, in particular in a wavelength range of 430 to 460 nm and may for example be in the form of an LED chip. In this wavelength range in particular so-called conversion phosphors in printing inks, which can also be used for the production of white light emitting LEDs, are excited.

For example, the conversion phosphors may be in the form of pigments added to an ink. The pigments can be excited by means of an LED flash and then emit a wavelength spectrum which differs from an excitation spectrum. The wavelength-converting pigments are thus excited in the color and cause a color shift of the color. This color shift is detectable, for example, as a wavelength shift with respect to a wavelength of the excitation light. This wavelength shift can be used for document recognition, in particular for recognizing the authenticity of a document, even using a smartphone. For example, a light emission spectrum, i. Color, the security feature when excited using an LED flash and without any excitation by the LED flash, for example, in daylight, are detected. In addition, the light emission spectrum of the security feature can be compared with a color space stored, for example, in a database. The database may for example be stored in a memory of the device. However, according to one embodiment, the database may be stored on a remote server to which the device communicates, for example via a communication network.

For example, if the security feature includes conversion phosphors, its emission spectrum is in the white color region in response to excitation in a wavelength range between 390 and 470 nm. In this case, color coordinates or a so-called CRI (Color Rendering Index), which can be greater than 80, are generated.

In order to excite the security feature, light pulses defined by the light generating device 101, for example by means of an LED flash unit of a smartphone, can be combined with a light pulse Pulse duration and a pulse interval of 0.05 ms to 100 ms, in particular from 0.5 ms to 10 ms are generated. Alternatively or for generating the reference light, a light pulse of 30 ms to continuous light can be generated.

The image pickup device 103 may comprise, for example, a color image sensor, for example a CCD sensor or a CMOS sensor or a FOVEON sensor, and comprise a shutter, global shutter and rolling shutter which has a shutter speed in the range of 0.05 ms to 100 ms, in particular from 10 ms to 50 ms, in particular in a range of 330 ms.

For recording production, the document, in particular the security feature, for example, twice recorded by the image pickup device 103, in particular photographed. For this purpose, the light-generating device 101 can be designed to generate at least two individual flashes during a recording closure time during the first recording in order to illuminate the document. The light generating device 101 may further be formed, in the second photograph, the document during the entire recording shutter time of the shutter system, i. by means of continuous light, to illuminate. However, the order of the shots or the order of the above-described light excitation patterns may be reversed.

According to one embodiment, at least two successive recordings are made, wherein a time interval in the range from 0.05 ms to 100 ms, in particular from 30 ms to 300 ms, can be set between the first recording and the second recording. In this case, one of the recordings can be used as reference record and the other record as emission record for document recognition.

If the document comprises at least one security feature with the luminescence properties described above, a specific spectral and / or temporal emission pattern is effected on account of the specific temporal and / or spectral excitation and decay characteristics of the security feature. In this case, one of the recordings described above can be used as a reference recording.

According to one embodiment, the device 100 uses both recordings for a comparison, which can be carried out by means of an application program running on the processor 105, for example for the authenticity check of the document. The verification result of the authenticity check of the document can, for example, on a Display device of the device 100, for example, on a display, visualized or acoustically signaled.

According to one embodiment, the device comprises a memory with a database in which a comparison reference is stored. On the basis of the first and second recordings, a comparison result is determined, which can be compared with the comparison reference for document recognition stored in the database. Here, predetermined criteria can be used to perform, for example, the authenticity check of the document. The result of the authenticity check can be visualized or acoustically signaled on a display of the device.

For performing the document recognition, the apparatus 100 may include an application program executing on the processor and driving the light generating means 101 to generate light for the respective shot. The application program may further synchronize the image pickup device 103 with the light generating device to obtain the respective shot.

According to one embodiment, the first recording, the second recording and / or the comparison result can be transmitted via a secure wireless connection via a communication network to a verification center, for example to a trust center. On the basis of the data transmitted to it, the verification center can carry out the document recognition, for example the authenticity check, and transmit the result of the authenticity check via a secured wireless connection back to the device. The device may then display the verification result on a display. For this purpose, the device can be set up to communicate in accordance with at least one of the aforementioned standards: ISM, Edge, UMTS, LTL, SMS; Bluetooth, WLAN, WMAX, femtocell or NFC. The transmission of the recordings and / or the comparison result, the receipt of the result of the document recognition and the display of the result on a display or the processing of the data to be displayed can be carried out by means of one or the aforementioned application program.

Fig. 2 FIG. 10 is a flowchart of a method of recognizing a document having a security feature with wavelength conversion characteristics. FIG. The method includes illuminating 201 the security feature with excitation light, capturing 203 a light emitted by the security feature in response to the excitation light to obtain an emission capture, capturing 205 one by the security feature in response to a reference light emitted light to obtain a reference recording, and the recognition 207 of the document based on the emission recording and the reference recording. The recording steps 103, 205 can be performed in any order.

This in Fig. 2 For example, the method illustrated may be implemented by means of an application program that includes the facilities of the in Fig. 1 shown device, which may be a smartphone, controls. Further process steps therefore arise directly from the functionality of in Fig. 1 illustrated device 100.

Reference numerals:

100

contraption

101

Light fixture

103

Image recording device

105

processor

201

light

203

take up

205

take up

207

Detect

Claims (12)

1. An apparatus for identifying a document having a security feature having wavelength conversion properties, comprising:

   a light-generation device (101), which is configured to illuminate the security feature using excitation light to emit light;

   an image recording device (103), which is configured to record light emitted by the security feature in response to the excitation light to obtain an emission recording, wherein the image recording device is furthermore configured to record light emitted by the security feature in response to a reference light to obtain a reference recording; and

   a processor (105), which is configured to identify the document on the basis of the emission recording and of the reference recording.
2. The apparatus as claimed in claim 1, wherein the light-generation device (101) is configured to illuminate the document using a predetermined number of light pulses so as to illuminate the security feature with the excitation light.
3. The apparatus as claimed in claim 2, wherein the light-generation device (101) is configured to generate the number of light pulses having a light pulse interval which lies in a predetermined light pulse interval range.
4. The apparatus as claimed in one of the preceding claims, wherein
   the reference light is white light, in particular daylight, or wherein
   the light-generation device (101) is configured to generate the reference light, in particular as a continuous light during the reference recording, or wherein
   the light-generation device (101) is configured to generate reference light pulses as the reference light during the reference recording.
5. The apparatus as claimed in one of the preceding claims, wherein the processor (105) is configured to compare the emission recording with the reference recording in order to obtain a comparison result and in order to identify the document on the basis of the comparison result.
6. The apparatus as claimed in claim 5, wherein the reference light has a predetermined wavelength, and wherein the processor (105) is configured
   to determine a wavelength difference between the predetermined wavelength and at least one wavelength of the emission light, or
   to determine a temporal wavelength profile of the emission light with respect to the predetermined wavelength, in particular a temporal profile of a wavelength amplitude or wavelength differences,
   in order to obtain the comparison result.
7. The apparatus as claimed in either of claims 5 and 6, wherein
   the processor (105) is configured to compare the comparison result with a previously stored comparison reference in order to identify the document, or wherein
   the apparatus comprises a transmitting/receiving unit which is configured to transmit the emission recording or the reference recording or a comparison result of a comparison between the emission recording and the reference recording via a communication network to a remote server for the purpose of document identification and, in response thereto, to receive a result of the document identification.
8. The apparatus as claimed in one of the preceding claims, which is a mobile communication device, in particular a smart phone, wherein the light-generation device (101) is an LED flash unit of the mobile communication device, and wherein the image recording device (103) is a digital camera of the mobile communication device.
9. The apparatus as claimed in one of the preceding claims, which has a program-technological design.
10. A method for identifying a document having a security feature having wavelength conversion properties, comprising:

    illuminating (201) the security feature using excitation light,

    recording (203) light emitted by the security feature in response to the excitation light to obtain an emission recording,

    recording (205) light emitted by the security feature in response to a reference light to obtain a reference recording, and

    identifying (207) the document on the basis of the emission recording and of the reference recording.
11. A computer program for executing the method as claimed in claim 10, if the computer program is executed on a mobile communication device, in particular on a smartphone.
12. A signal sequence, in particular a signal sequence which is transmittable via a communication network such as the Internet, which signal sequence represents data which represent the computer program as claimed in claim 11.

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