DE102009025324A1 - Recording device i.e. document scanner, for recording spatial structures of e.g. passport, in safety technology area, has image point-recording units recording defined image points of levels that exhibit different distances to surface - Google Patents

Abstract

The device (1) has a contact surface (2) i.e. contact plate, arranged relative to an object. A contact-image sensor (5) is arranged adjacent to the contact surface for recording of the object that is arranged relative the surface. The contact-image sensor comprises image point-recording units (6-1-6-6), which comprise imaging units (7-1-7-6) e.g. rod lens and micro lens, and pixel detection units (8-1-8-6). The image point-recording units are utilized for recording defined formed image points of levels (18, 19) of the object, where the levels exhibiting different distances to the surface. An independent claim is also included for a method for recording image points of the object.

Description

The The invention relates to a method and a detection device to capture spatial structures of an object. Especially the invention relates to a detection device which has a contact surface, relative to which an object to be detected can be arranged, an adjacent one arranged to the contact surface contact image sensor for Detecting the object disposed relative to the contact surface wherein the contact image sensor comprises a plurality of pixel detection units each comprising an imaging unit and at least one Pixel detection unit, wherein the imaging units respectively Sections of relative to the contact surface, preferably in contact with the contact surface arranged object, map to the respective at least one associated pixel detection unit, wherein the pixel detection units comprise incident imaged electromagnetic Convert radiation into electrical signals. With such a detection device It is possible to have an object which is relative to the contact surface is arranged, preferably in contact with the contact surface is arranged to optically detect. The pictured electromagnetic Radiation is converted into electrical signals, which is a measure of represent a received light intensity.

Such Detecting devices and such methods for detecting a Objects are used, for example, in scanners. In the prior art is a variety of scanners for capturing objects, for example Paper documents, known. In addition, scanners become used in the field of safety technology for various tasks. For example, scanners in the field of verification of value and / or security documents known for machine detection used by information of the value and / or security document and then a verification of the recorded To execute information. Here are in particular Security features and security elements of the corresponding value and / or security document recorded and evaluated.

When Value and / or security document is called a document, which at least one so-called security feature or security element having. Security features are those features imitating, falsifying and / or copying the value and / or Make the security document difficult and / or impossible. As a security element, a structural unit is called, the includes or represents at least one security feature. Value- and / or security elements include, for example, passports, Identification cards, identity cards, driver's licenses, Vehicle registration certificates, tax stamps, postage stamps, credit cards, banknotes, Securities, etc. In the field of security technology are about In addition, for example, scanners for acquiring biometric data, used for example by papillary line patterns. The papillary line pattern a human's finger is individual to each person characterizing. This means that an identification over a pattern recognition of the papillary lines with a very high reliability is possible.

However, it is known that the pattern of a person's papillary line can be reproduced. For this example, a plastic coating can be applied to a finger-like dead object or a living finger of another person. In order to distinguish between a living person's papillary line pattern and a fake ridge-line pattern, it is known in the art to detect not only information of the surface on which the ridge line pattern is optically detectable, but also the "depth" of the finger , From the WO 98/35118 For example, an identification device is known which has a unit for detecting biometric features and a unit for detecting the vitality of a person. Only when it is recognized that the person to be identified actually lives, the acquired biometric features are compared with stored person-specific features to perform an identification. For detecting the biometric signals, it is proposed, for example, to emit and receive electromagnetic signals or acoustic signals. With electromagnetic signals in the optical range, preferably in the infrared wavelength range, the detection of an external fingerprint, ie the papillary lines on the surface, is proposed. By transmitting and receiving acoustic signals is described to capture both the external fingerprint and an internal fingerprint (an epidermis inside the finger). In order to determine the vitality of the finger, further sensors, for example a pulse detection unit, are provided.

Generally There is a need to keep getting new and more complex security features for security documents and more sophisticated ones Detection devices and methods to provide complex security features and / or to safely capture biometric features and thereby counterfeits or falsification of security features or biometric Reliably recognize features. Furthermore The detection devices and methods should be simple and inexpensive be executed as well as the detection devices a have sufficient robustness, even in portable units to be used.

A Ability to create complex security features consists of spatial structures as security features to use. In value and / or security documents can different on different levels of the document Information stored for example for a human viewer one over a surface represent distributed information. For example, you can the pixels of a face image in different levels of the document be saved. This means the individual pixels of the face image are stored in different levels of the document. Be over the pixels only transparent layers arranged so the facial image is perceptible to a viewer as a whole. Only with a detailed analysis can be found that individual pixels are arranged in different levels.

at The collection of papillary line patterns can over a spatial detection, d. H. a collection in different Levels of the object that are achieved only superficially developed papillary line pattern of papillary line patterns more alive Fingers can be distinguished, since with these the papillary line pattern has a greater spatial depth.

Of the Invention is therefore the technical object of a detection device and to create a process with which spatial structures can be detected optically.

The The invention is based on the idea of a contact image sensor (Contact Image Sensor - CIS) for capturing pixels to use. Such a contact image sensor comprises a plurality of Pixel detection units. The pixel detection units include each an imaging unit, which is a section of an object maps to a pixel detection unit. The pixel detection unit converts the imaged electromagnetic radiation into an electrical one Signal. This is proportional to the imaged intensity the electromagnetic radiation. The contact image sensor is facing the known from the prior art contact image sensors so modified to be sharp by means of the pixel detection units pictured pixels of at least two different ones Distance to a contact surface, relative to the contact image sensor is arranged, exhibiting levels of the object are detectable or recorded become. A method of capturing pixels of an object with a contact image sensor relative to the contact surface is arranged and a plurality of pixel detection units each comprising an imaging unit and at least one Comprise pixel detection unit, thus comprising the steps: Arrange of the object relative to the contact surface, detecting Pixels of the object, wherein the imaging units each sections of the relative to the contact surface, preferably in contact with the contact surface, arranged object on the respective map at least one associated pixel detection unit and the pixel detection units the imaged electromagnetic Convert radiation into electrical signals, which is a measure of represent a received light intensity. Here is provided that by means of the pixel detection units sharp imaged pixels of at least two a different distance captured to the contact surface having planes of the object become. If a pixel of the object is focused on a pixel detection unit Imaged, so is a maximum intensity at the pixel of the object reflected diffracted or scattered radiation the pixel detection unit mapped. This assumes that one pixel is bright (for example, white) in front of a dark one Background (for example, black). Becomes a pixel of a mapped to another level, its image is in the pixel detection level widened, so that part of the light intensity is not is detected.

When sharply imaged is a pixel called, if that captured pixels together with other pixels from other pixels a structure to a resolved and contrasting picture contributes to the structure. That is, that from a section of the object in the plane concerned (at a bright pixel), d. H. focused becomes. This is a selective mapping regarding a distance from the contact image sensor. The pixels will be detected so that the detected pixels an information content of a play back at a certain level.

Prefers thus becomes an active area of the pixel detection unit adapted to a minimum size of a spicy imaged pixel of the object of a respective imaging unit a pixel detection unit selected. Next to the focal length has on this, among other things, a choice of an aperture on the exit side the imaging unit has an influence.

Of the Advantage of the device according to the invention and the process of the invention is that information from different levels can be detected or be comprehended and spatially verified for verification trained security features or biometric features can be.

In one embodiment of the invention, it is provided that the different pixel detection units, which he sharply imaged pixels of the different levels of the object he summarize, imaging units of different imaging properties, in particular different focal length, have. If, for example, pixels of second different planes are to be detected, two different types of pixel detection units exist, which at the same time detect the pixels of the different planes. These different types of pixel detection units each have different imaging units that have different imaging properties. For example, one type of pixel detection unit includes imaging units having a first focal length and the other type of pixel detection unit has imaging units having a different focal length that deviates from the first focal length.

Around to facilitate a calibration of the individual pixel detection units, the image contact sensor is preferably formed so that a Pixel density of pixel detection units larger is shown as a pixel density in the object, i. H. as a minimal Structure size to be captured. This means, that the structures of the object to be detected in a plane respectively have a lateral extent through at least two adjacent Pixel detection units mapped to two captured image pixels become.

advantageously, the at least two different levels are alternated by evenly arranged pixel detection units, the imaging units with different imaging properties detected. Point the structures containing the information, which are recorded and are to be evaluated laterally in the planes each expansions which are mapped by several adjacent detected pixels, so a clear signal difference of adjacent pixels can be detected. In each case only one of two adjacent pixel detection units sharpens the corresponding structure of the object when you assumes that only one level of the object at a time Information in the form of a laterally formed in the plane Structure is formed.

Around to achieve a good separation of the individual levels of the object, it is advantageous if the individual imaging units of the pixel detection units each have a low depth of field. This can be achieved, on the one hand, by the imaging units with the largest possible numerical aperture be formed.

at In a preferred embodiment, the imaging units comprise Rod lenses. With these can be particularly favorable the realize desired imaging properties.

Around a good resolution, d. H. Assignment of the collected information to get to the individual levels that are captured is provided in a preferred embodiment, that the focal lengths of the imaging units of the pixel detection units when capturing the sharply imaged pixels of the different Levels differ by at least one value, of the order of magnitude a value of a maximum length of the depth of field lies corresponding to the imaging units when capturing the pixels exhibit.

Around achieve a resolution in the range of 100 μm, Therefore, the depth of field is less than 100 microns to choose. For this purpose, on the one hand, the numerical aperture to choose the imaging unit as large as possible. On the other hand, an active area is the pixel size to choose as small as possible. Preferred embodiments therefore have a diameter of an active area of Pixel detection units of the order of magnitude the wavelength of the electromagnetic radiation, which is converted. Becomes green light, for example used, which has a wavelength in the range of 550 nm have active areas of the pixel detection units in the order of 1 micron desirable.

Around to be independent of chromatic aberration is at a preferred embodiment provides that a or a plurality of light elements relative to the contact surface are arranged to monochromatically illuminate the object to be detected. In some embodiments, there are several different ones Light source provided, the light of different wavelength, z. B. in the infrared wavelength range in the visible and in the ultraviolet wavelength range. The different ones Illuminants can be controlled so that the object each monochromatically illuminated with one of the wavelengths becomes. To obtain a uniform illumination, are preferably in each case a plurality of bulbs present, the light of the same Generate wavelength.

Around Achieving high flexibility is at a preferred level Embodiment provided that at least part of the Plurality of pixel detection units include imaging units that modifiable in terms of their imaging properties are.

In a further development, in which the imaging units comprise lenses, preferably rod lenses, it is provided that the lenses of the imaging units of the part of the plurality of pixel detection units which are modifiable in terms of their imaging properties modifiable, deformable and together, in Grup or individually coupled to an actuator, via which a deformation of all lenses of the group of lenses or of the individual lenses can be effected in order to modify the optical properties. Piezo crystals, for example, can be arranged adjacent to the lenses as actuators in order, for example, to achieve an extension of the lenses. Other embodiments provide that over a compression or elongation, a radius of curvature of the exit surface of the lenses is modified to achieve a focal length modification.

Preferably is coupled to the contact image sensor an evaluation, the is designed to determine whether and which by the captured pixels embodied information in the different levels of the object are stored. The object that captures is, for example, a finger or a value and / or Act security document.

The Features of the method according to the invention the same advantages as the corresponding features of the detection device on.

following The invention is based on preferred embodiments explained in more detail. Hereby show:

1 a schematic representation of a trained as a document scanner detection device;

2 a schematic representation of another embodiment in which individual pixel detection units include modifiable imaging units;

3 a further embodiment with modifiable imaging units; and

4 a plan view of another embodiment of modifiable imaging units.

In 1 schematically is a detection device 1 shown. The detection device 1 is designed as a document scanner. The detection device 1 includes a transparent contact surface 2 , The transparent contact surface 2 is designed here as a support plate. This includes a housing 3 to a top 4 down. In the case 3 , adjacent to the contact surface 2 , is a contact image sensor 5 arranged. The contact image sensor 5 includes individual pixel detection units 6 ,

In the figures, the reference numeral " 6 "Appended a hyphenated number to the individual pixel detection units 6 to distinguish. When referring to all pixel detection units, the reference numeral " 6 "Used without trailing number. In analogy, it deals with other features and entities that occur multiple times.

Each pixel detection unit 6 includes an imaging unit 7 and a pixel detection unit 8th , The imaging units 7 are formed in the illustrated embodiment as rod lenses (rodlenses). Each pixel detection unit 6 forms a section 9 of a document 10 from. Here is the document 10 with his front 11 arranged in contact with the contact surface. The imaging units 7 the individual pixel detection units 6 each form one of the sections 9 to the associated pixel detection unit 8th from. The pixel detection units 8th convert the received imaged electromagnetic radiation into an electrical signal.

The pixel detection units 8th are on a common substrate 12 , preferably by means of CMOS technology. The converted signals of the pixel detection units 8th are sent to a control unit 13 forwarded. This usually includes an evaluation unit 14 that evaluates the received electrical signals. To the document 10 to illuminate are one or more bulbs 15 intended. These generate monochromatic radiation, which is the document 10 from its front 11 that are in contact with the contact surface 2 is, illuminate. The illumination can take place both in the visible wavelength range and in the ultraviolet or infrared wavelength range. It is also possible that the excitation takes place at a wavelength which deviates from the wavelength which is determined by the contact image sensor 5 is detected. This is advantageous if the structures to be detected 16 . 17 , about the information in the document 10 are encoded as luminescent structures are formed. Some embodiments have different light sources, so that a specific wavelength can be selected for the illumination.

The structures 16 . 17 are in different levels 18 . 19 arranged at a different distance to the front 11 of the document 10 and thus to the contact surface 2 exhibit.

The imaging units 7 the individual pixel detection units 6 are formed differently. Alternating are the imaging units designed as rod lenses in this embodiment 7 a different focal length. This means that the imaging units 7 alternately changing imaging properties exhibit. The imaging units 6-1 . 6-3 . 6-5 , the rod lenses of the schematic representation are shown longer, are formed so that they pixels or a structure 16 the level 18 sharp on the pixel detection units 8-1 . 8-3 . 8-5 depict. The shorter illustrated imaging units 6-2 . 6-4 . 6-6 On the other hand, they are designed to be pixels or a structure 17 the level 19 sharp on the pixel detection units 8-2 . 8-4 . 8-6 depict. A depth of field of the imaging units 7 is each chosen so that this is less than a distance between the two levels 18 . 19 from each other.

The pixel detection units 6-1 to 6-3 form the structure in the example shown 16 starting in the plane 18 is arranged. Here are the sections 9-1 to 9-3 according to the pixel detection units 6-1 to 6-3 mapped and captured. The imaging units 7-1 and 7-3 in each case form those in the sections 9-1 and 9-3 lying portions of the structure 16 sharp on the pixel detection units 8-1 and 8-3 from. Scharf in this context means that the light detected by the respective section is focused on the active surface of the respective pixel detection unit 8-1 respectively. 8-3 is focused. The image point detection unit 6-2 on the other hand has a imaging unit designed as a microlens 7-2 on that for a sharp, ie focused image of light from the plane 19 is trained. The in the section 9-2 lying portion of the structure 16 is thus not sharp, ie not focused on the pixel detection unit 8-2 displayed. Rather, the light cone passing through the lens is in the region of a detection plane 20 in which the pixel detection units 8th are widened. Thus, between the pixels that are with the pixel detection units 8-1 and 8-3 and the pixel associated with the pixel detection unit 8-2 is detected, a clear contrast recognizable. It should be noted that an active area of the pixel detection units 8th is selected in each case adapted to a focus size, in the area of which the light of a pixel of the corresponding intended plane, which is sharply imaged, is collected.

The same applies to the pixel detection units 6-4 to 6-6 , The pixel detection units 6-4 and 6-6 are for capturing pixels in the plane 19 trained, the. Contact surface is more approximate than the plane 18 of the document 10 , The pixel detection unit 6-5 is, on the other hand, designed to be pixels of the plane 18 sharply focused on the corresponding pixel detection unit 8-5 map. For those in the field of sections 9-4 to 9-6 lying portions of the structure 19 Now it holds that these from the pixel detection units 6-4 and 6-6 sharp on the corresponding pixel detection units 8-4 and 8-6 be imaged. On the other hand, the share of structure 17 in the section 9-5 not keen on the corresponding pixel detection unit 8-5 displayed. Again, a contrast difference can be detected. This makes it possible to decide whether the structure detected 16 . 17 in the plane 18 or the level 19 lies.

It shows that it is advantageous the detected pixel resolution to choose so that each structural unit by at least two pixels, preferably better 3 pixels, is imaged to avoid possible edge errors, d. H. a non-optimal orientation of the structure with respect better able to process the captured pixels. There are However, embodiments are also possible in which Structures up to a 1: 1 assignment Pixel: captured pixel possible are. In this case, however, a good calibration is necessary to reliably determine from which Level electromagnetic radiation is detected.

The contact image sensor may be formed in a line-shaped or matrix-shaped manner. At the in 1 The illustrated embodiment is the contact image sensor 5 assumed as a line. About the scan actuator 21 can be the contact image sensor 5 moved perpendicular to the drawing plane to the document 10 to capture areally.

Via an interface 29 can the control unit 13 Exchange information, such as evaluation results, with other devices. The interface can be designed, for example, as a network interface.

In 2 a further embodiment of a detection device is shown. The same technical features are provided here with the same reference numerals. In an upper portion is a plan view of the line-shaped contact image sensor 5 shown. The lower section shows a schematic side view. Deviating from the embodiment according to 1 is in the embodiment according to 2 alternating every other imaging unit 7-1 . 7-3 . 7-5 designed modifiable. The individual imaging units designed as rod lenses 7-1 . 7-3 . 7-5 are with a mechanics 22 connected via a lens actuator 23 are deformable together in terms of their length. This will cause a focal length of the corresponding imaging unit 7-1 . 7-3 . 7-5 modified. In this arrangement, for example, the non-modifiable in terms of their length imaging units 7-2 . 7-4 and 7-6 configured to focus pixels in a plane of a pad (not shown) on the corresponding pixel detection units 8-2 . 8-4 . 8-6 Imagine modifying the lengths of the rod lenses of the imaging units 7-1 . 7-3 . 7-5 a distance can be varied which the plane has to the contact surface, which detek should be. As a result, a higher flexibility is created because documents of different construction can be detected and evaluated with the same detection device, in which the individual arranged in different levels structures have different distances to the contact surface.

3 shows a modification of the device according to 2 , In this embodiment, all mapping units are 7-1 to 7-6 variable executed. Here, the mapping properties can be modified in groups. The imaging properties of the rod lenses of the imaging units 7-1 . 7-3 . 7-5 can as in the embodiment according to 2 be modified in terms of their length. In the embodiment according to 3 However, they are also the imaging units designed as rod lenses 7-2 . 7-4 . 7-6 with another mechanics 23 and another modification actuator 24 coupled.

In this embodiment, the imaging units 7 both groups of pixel detection units 6 be modified in terms of their imaging properties. Thus, in this embodiment, two levels, freely selectable within limits of a contact surface, can be detected. In the embodiment according to 3 In addition, it is possible to capture the same portions of the document one after the other with different imaging characteristics of the two groups of pixel detection units. In addition to a lateral variation of the signal, a temporal variation due to a change in the imaging characteristic of the associated imaging unit of a respective pixel can also be evaluated. Particularly advantageously, the groups of imaging units are set so that they each time alternately time sequentially map the corresponding levels. For example, at one time, the pixel detection units form 6-1 . 6-3 . 6-5 a first level and the pixel detection units 6-2 . 6-4 . 6-6 a second level off. At a subsequent time, the mapping units are modified so that now the pixel detection units 6-1 . 6-3 . 6-5 the second level and the pixel detection units 6-2 . 6-4 . 6-6 capture the first level.

It will be understood by those skilled in the art that extending the rod lenses is only one possible modification of the imaging properties. In 4 is a schematic plan view of another type of imaging units 7-1 to 7-4 displayed. Shown is a plan view of cylindrical lens elements 26 , Adjacent to the lens elements 26-1 to 26-4 are piezo elements 27-1 to 27-4 arranged. About these can be the lens elements 26-1 to 26-4 individually compressed, resulting in radii of curvature of the lens elements 26 vary this is exemplified in a lower area for a lens element 26-1 shown schematically. While bottom left is the lens element 26-1 is shown undeformed, right below is the lens element 26-1 through the piezo elements 27-1 shown compressed so that a radius of curvature 28 is changed. As a result, the imaging properties change so that another plane of an object is focused sharply relative to the lens element 26-1 arranged pixel detection unit is mapped.

described are embodiments with line-shaped image contact sensors. Other embodiments may be matrix-type image contact sensors include.

It It will be understood by those skilled in the art that merely exemplary Embodiments are described schematically. The illustrated Dimensions do not correspond to the real dimensions, but are chosen for the purpose of illustration only.

1

detection device

2

contact area

3

casing

4

Top (of the housing 3 )

5

Contact Image Sensor

6 6-1 ... 6-6

Pixel detection unit

7, 7-1 ... 7-6

imaging unit

8th, 8-1 ... 8-6

Pixel detection unit

9 9-1 ... 9-6

section

10

document

11

front

12

substratum

13

control unit

14

evaluation

15

Lamp

16 17

structures

18 19

levels (of the document / object)

20

detection plane

21

Scanaktor

22

mechanics

23

Linsenaktor

24

Further mechanics

25

Another Linsenaktor

26

lens element

27

piezo element

28

radius of curvature

29

interface

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 98/35118 [0004]

Claims (23)

Detection device ( 1 ) comprising a contact surface ( 2 ), relative to which an object to be detected can be arranged, one adjacent to the contact surface ( 2 ) arranged contact image sensor ( 5 ) for detecting the relative to the contact surface ( 2 ), wherein the contact image sensor ( 5 ) a plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ), each having an imaging unit ( 7 . 7-1 , ..., 7-6 ) and at least one pixel detection unit ( 8th . 8-1 , ..., 8-6 ), wherein the imaging units ( 7 . 7-1 , ..., 7-6 ) sections of each relative to the contact surface ( 2 ), preferably in contact with the contact surface ( 2 ) arranged on the respective at least one associated pixel detection unit ( 8th . 8-1 , ..., 8-6 ), the pixel detection units ( 8th . 8-1 , ..., 8-6 ) convert incident electromagnetic radiation into electrical signals, characterized in that by means of the pixel detection units ( 6 . 6-1 , ..., 6-6 ) sharply imaged pixels of at least two a different distance to the contact surface ( 2 ) ( 18 . 19 ) of the object are detectable or detected. Detection device ( 1 ) according to claim 1, characterized in that the different pixel detection units ( 6 . 6-1 , ..., 6-6 ), which display the sharply-imaged pixels of the different levels ( 18 . 19 ) of the object, imaging units ( 7 . 7-1 , ..., 7-6 ) having different imaging properties, in particular different focal lengths. Detection device ( 1 ) according to claim 1 or 2, characterized in that at least a part of the plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ) Imaging units ( 7 . 7-1 , ..., 7-6 ) that are modifiable under the control of their imaging properties. Detection device ( 1 ) according to one of the preceding claims, characterized in that the imaging units ( 7 . 7-1 , ..., 7-6 ) Rod lenses include. Detection device ( 1 ) according to claim 4, characterized in that the lenses of the imaging units ( 7 . 7-1 , ..., 7-6 ) of the part of the plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ), which are controlled in terms of their imaging properties modifiable, are deformable and are coupled together, in groups or individually with an actuator, on the corresponding deformation of all lenses, the group of lenses or the individual lens is effected to the optical properties modify. Detection device ( 1 ) according to one of the preceding claims, characterized in that the at least two different levels ( 18 . 19 ) by means of alternately arranged pixel detection units ( 6 . 6-1 , ..., 6-6 ), the imaging units ( 7 . 7-1 , ..., 7-6 ) having different imaging properties, are detectable. Detection device ( 1 ) according to one of the preceding claims, characterized in that a diameter of an active area of the pixel detection units ( 8th . 8-1 , ..., 8-6 ) is on the order of the wavelength of the electromagnetic radiation that is being converted. Detection device ( 1 ) according to one of the preceding claims, characterized in that one or more light-emitting elements relative to the contact surface ( 2 ) are arranged to monochromatically illuminate the object to be detected. Detection device ( 1 ) according to one of the preceding claims, characterized in that the focal lengths of the imaging units ( 7 . 7-1 , ..., 7-6 ) of the pixel detection units ( 6 . 6-1 , ..., 6-6 ) upon detection of the sharply-imaged pixels of the different planes differ at least by a value which is of the order of magnitude of a maximum length of the depth-of-field regions which the imaging units ( 7 . 7-1 , ..., 7-6 ) accordingly when capturing the pixels. Detection device ( 1 ) according to one of the preceding claims, characterized in that an evaluation unit is provided to determine whether and which are represented by the pixels embodied information in the different planes of the object. Detection device ( 1 ) according to one of the preceding claims, characterized in that the object is a finger or a security document. Method for capturing picture elements of an object with a contact image sensor ( 5 ), which is relative to a contact surface ( 2 ) is arranged and a plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ), each having an imaging unit ( 7 . 7-1 , ..., 7-6 ) and at least one pixel detection unit ( 8th . 8-1 , ..., 8-6 ), comprising the steps of: arranging the object relative to the contact surface ( 2 ), Capturing pixels of the object, wherein the imaging units ( 7 . 7-1 , ..., 7-6 ) sections of each relative to the contact surface ( 2 ), preferably in contact with the contact surface ( 2 ), arranged object on the respective at least one associated Pixel detection unit ( 8th . 8-1 , ..., 8-6 ) and the pixel detection units ( 8th . 8-1 , ..., 8-6 ), which convert the imaged electromagnetic radiation into electrical signals which represent a measure of a received light intensity, characterized in that by means of the pixel detection units ( 6 . 6-1 , ..., 6-6 ) sharply imaged pixels of at least two a different distance to the contact surface ( 2 ) ( 18 . 19 ) of the object. Method according to claim 12, characterized in that the sharply imaged pixels of the at least two different planes ( 18 . 19 ) of the object by means of the pixel detection units ( 6 . 6-1 , ..., 6-6 ) whose mapping units ( 7 . 7-1 , ..., 7-6 ) have different imaging properties, in particular different focal length. A method according to claim 12 or 13, characterized in that at least for a part of the plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ) the imaging units ( 7 . 7-1 , ..., 7-6 ) can be modified in terms of their imaging properties in order to be able to acquire the pixels of the different planes ( 18 . 19 ) of the object to create different imaging properties. Method according to one of claims 12 to 14, characterized in that the cutouts of the object by means of Rod lenses are displayed. A method according to claim 15, characterized in that the rod lenses of the imaging units ( 7 . 7-1 , ..., 7-6 ) of the part of the plurality of pixel detection units ( 6 . 6-1 , ..., 6-6 ), which are modified in terms of their imaging properties, are deformed. Method according to one of claims 12 to 16, characterized in that the pixels of the at least two different levels ( 18 . 19 ) relative to a lateral extent of the contact image sensor ( 5 ) are detected evenly alternately. Method according to one of claims 12 to 17, characterized in that the pixels of the at least two levels ( 18 . 19 ) are staggered in time. Method according to one of claims 12 to 18, characterized in that the object with monochromatic electromagnetic Radiation is illuminated. Method according to one of claims 12 to 19, characterized in that the sharply imaged pixels of the different planes with focal lengths of the imaging units ( 7 . 7-1 , ..., 7-6 ) of the pixel detection units ( 6 . 6-1 , ..., 6-6 ) which differ at least by a value which is of the order of a value of a maximum length of the depth of field which the image units ( 7 . 7-1 , ..., 7-6 ) accordingly when capturing the pixels. Method according to one of claims 12 to 20, characterized in that the detected pixels evaluated to determine if and which represented by the pixels Information stored in the different levels of the object are. Method according to one of claims 12 to 21, characterized in that papillary lines in at least two planes of a finger and with regard to an equality of the patterns be evaluated. Method according to one of claims 12 to 22, characterized in that information from at least two levels a value and / or security document are read out and evaluated, to do a verification.