EP2622539A1

EP2622539A1 - Method and device for the non-contact detection of biometric features

Info

Publication number: EP2622539A1
Application number: EP11764524.2A
Authority: EP
Inventors: Alexander Lenhardt
Original assignee: Icognize GmbH
Current assignee: Icognize GmbH
Priority date: 2010-09-28
Filing date: 2011-09-27
Publication date: 2013-08-07
Also published as: WO2012041826A1; DE202011109909U1

Abstract

The invention relates to a device for detecting biometric features of body parts, comprising a housing (10) which accommodates a biometric sensor (1) and has a sensor surface (2) which is able to detect, in a non-contact manner, biometric features of a body part (3) arranged at a distance in front of the sensor surface. In order to create a method and device for detecting biometric features having the aforementioned features, which also operate reliably in a non-contact manner in everyday operation, according to the invention units are provided for projecting an optical pattern that varies with the distance (d) from the sensor surface (2) onto a surface (3a) that can be moved together with the body part (3).

Description

Method and device for non-contact detection of biometric features

The present invention relates to a device for non-contact detection of biometric features, comprising a housing receiving a biometric sensor, which presents a sensor surface that can detect biometric features of a body part arranged at a distance in front of the sensor surface without contact.

Likewise, the present invention also relates to a method for non-contact detection of biometric features of body parts, wherein a body part at a distance from a sensor surface for detection by the sensor is presented.

As biometric features are in particular fingerprints, images of the eye iris and z. As well as infrared images of the hand veins, although fingerprints generally do not fall under the category "contactless", but in principle could also be detected without contact with the help of suitable optical detection devices.

Biometric data is increasingly being used to identify and authenticate individuals, such as cell phones or personal computers or laptops. In these devices, touch fields or touch fields are mostly still used, wherein the user can place one or more fingers of a hand on such a field or can lead across this, wherein the fingerprint is scanned. Although the eye iris can be scanned without contact with a considerable distance of the sensor surface of the eye surface, but ultimately this method is not really contactless, because the user is forced in practice to create a reliable recording, his forehead or other facial parts on a suitable Position the support so that the eye scanner can detect the iris for a sufficient time at a safe scannable distance.

These effectively non-contact methods are particularly problematic in the case of access controls, which must be passed by a large number of different people because of the risk of contamination associated with the direct contact.

Not least for this reason, but also because of the very good discriminability, palm vein scanner begin to prevail more and more, in which by infrared sensors Image of the venous structure in the hand of a person is detected, which has a pronounced degree of individuality. In this method, the person to be authorized would only need to hold his hand in a certain distance, typically 5 to 20 cm, in front of a sensor surface, which is located on or in a housing, ideally without touching the housing. However, experience has shown that this also causes problems since many persons can not estimate the correct distance and / or do not keep their hand sufficiently quiet, so that in practice the need for using hand supports has proven to be reliable even with these devices. which ensure that the user holds his hand in front of the sensor surface for a sufficient length of time and sufficiently quietly.

Compared to this prior art, the present invention seeks to provide a method and apparatus for detecting biometric features with the features mentioned that work reliable contactless in everyday use. With regard to the device mentioned in the introduction, this object is achieved in that means are provided for projecting an optical pattern changing with the distance to the sensor surface onto a surface which is movable together with the body part.

With regard to the aforementioned method, this object is achieved in that for determining a suitable detection distance, an optical pattern is projected into the space in front of the sensor surface that changes with change of the distance from the sensor surface.

With the help of the method according to the invention and the corresponding device it is possible to provide the respective user during the detection of the biometric features feedback on the correct position of the body part to be detected such. B. his hand, so that the user has thereby an immediate control over the process of feature detection. The user observes the pattern projected on a surface of the body part or a moving surface as the body part is brought in, and holds the body part, for example, his hand, so that the pattern takes on a predetermined appearance characteristic of the proper distance and position , As the pattern changes with distance to the sensor surface, the pattern at the "right" or "desired" distance has an appearance that is different from the appearance at other distances not intended for detection. The user therefore only has to adjust the distance between the body part and the sensor surface in such a way that the relevant desired pattern appears on the surface of the body part or a moving surface. This desired pattern (and possibly also the deviating patterns at undesired intervals) could be presented to the user, for example, on a scoreboard or instruction manual and the user can then create the desired pattern on the corresponding surface of the body part by varying the distance to the sensor surface. It is not a mm-exact silence required, but it is enough if the user his hand for 1 second within a tolerance deviation of z. B. ± 10 mm around the optimal distance keeps around. The easily recognizable, characteristic pattern is a great help to the user and therefore speeds up the process considerably, since the number of failed attempts compared to other unsupported procedures drastically decreases and the process itself is accelerated, because the user due to the optical Feedback about his visual perception much faster finds the right position of the body part.

The pattern to be set may, for example, be shown or displayed next to the sensor device for explanation. Once the projected pattern on the surface has assumed the specified shape, the person knows that they have positioned their hand in the correct location. It would also be conceivable for the projected pattern to be detected automatically by a second recognition device and for the persons to be identified to be informed about the position of their hand, for example via acoustic feedback signals. Such an expanded recognition device would be suitable for visually impaired people, for example. In the following, merely by way of example and without limitation, the hand of the human body will be considered as the body part on which the biometric features are detected. It is understood, however, that the corresponding features of the invention may be used identically or analogously also in the detection of other biometric features. For example, in the detection of the eye iris, the pattern could be projected onto the forehead or root of the nose of a user, who can observe this in a mirror and adjust the distance accordingly.

The inventive method and the corresponding device work completely contactless and thus eliminate the otherwise existing risk of contamination when using the same device by numerous people, such as access controls to company premises, security areas, etc.

Incidentally, it will be understood that the device features of preferred embodiments defined below and in the claims imply corresponding method features, and vice versa, and in the following description, device and method features are not always clearly separable from one another and refer to both categories. The means for projecting the optical pattern are preferably provided adjacent to the sensor surface, which facilitates the projection of the pattern onto a palm of the hand.

Conveniently, the means for projecting the optical pattern are provided on the housing.

In particular, the means for projecting the optical pattern are provided along the circumference of the sensor surface and at a distance therefrom. For optimal distance adjustment, it is also advantageous if the means for projecting the optical pattern along the circumference of the sensor surface are arranged distributed at approximately equal angular intervals around the center of the sensor surface, because then the pattern has a fast and uniformly varying distance dependence with respect to all pattern elements.

A variant is preferred in which the means for the projection of the optical pattern each generate a light beam, wherein these multiple beams are not all parallel. A plurality of such devices accordingly generate a plurality of spots on a projection surface, the relative arrangement of which defines a distance-dependent pattern unless all the light rays are parallel.

In this case, it may also be expedient for the devices for the projection of the optical pattern to comprise optical collimator devices. These may be in the simplest form as tubular optical conductors, glass fibers or the like. The means for projection of the optical pattern may in particular comprise light-emitting diodes which form the sources of light beams.

In particular, the means for projecting the optical pattern may comprise laser diodes.

A variant is also feasible in which a light beam emanating from a single source is split by optical refraction into a plurality of beams, which are then projected onto a body part from different points. In a rectangular sensor field, it is provided in a variant that the means for projecting the optical pattern are respectively assigned to the corners and centers of the sides of the sensor rectangle. In general, in the preferred embodiment, the means for projecting the optical pattern are arranged and configured such that the light beams emanating from you generate a characteristic pattern in a distance desired for the acquisition of a biometric feature that differs from the pattern generated at other distances mere human eye is different. Alternatively, a machine differentiation of the patterns at different distances is certainly possible, but this would require further, for example, acoustic feedback devices to achieve the object according to the invention in order to allow the user a contactless adjustment of the distance between hand and sensor surface. The latter would be useful, for example, when used by Sehbe hinderte.

The pattern becomes particularly simple and easily distinguishable at various distances when the means for projecting the optical pattern are arranged and configured such that the light beams emanating from them cross at most three and preferably only one common point in the space in front of the sensor surface. The crossing points are preferably at the desired distance and the pattern is then characterized by a minimum number of points, in the preferred case a single point, while at other distances the pattern is formed by a larger number of points.

Ideally, the patterns for generating the patterns are aligned in such a way that the pattern produced at a desired spacing is located in front of the sensor surface in the region of a normal starting from the center of the sensor surface.

Otherwise, the projection of the pattern can alternatively take place on a side facing the sensor surface or on the side facing away from the sensor surface or both or other sides of the body part.

In a preferred variant of the invention, therefore, the pattern is projected in the form of a plurality of light beams onto the skin surface of the body part or a co-moving surface (for example of a glove). By observing the pattern and generating a desired pattern known or given to the user, the user then positions his hand at the location suitable for acquiring the biometric characteristics so that the detection process can proceed.

Also possible is a variant in which a secondary sensor, in turn, detects the pattern projected onto the hand surface and aligns it with a desired, stored pattern, wherein it can also emit an acoustic signal to give the user feedback about the correct positioning. Another secondary sensor may also be useful, for example, to detect whether and when a body part enters the detection area of the primary sensor for the biometric features in order, for example, to put into operation only the means for generating the pattern and / or the primary sensor, to save energy for sensor operation in this way.

For a preferred variant, it has proven to be expedient if the light rays emanating from the means for generating the same intersect at angles of more than 20 °, preferably more than 40 °. The maximum angle of intersection of two light beams is of course below 180 °, preferably below 130 ° and in particular below 100 °. In one of a plurality of sources greater than 2 outgoing field of intersecting light beams, the intersection angles of pairs of light rays in general, but are preferably all within the above-defined areas. For example, in one embodiment, a sensor surface is surrounded by 8 sources of light rays located at the corners and at the center of the sides of a (imaginary) rectangle, respectively. For example, this rectangle could have dimensions of 8 x 12 cm ² , so that as a result the minimum distance between two light sources is 4 cm (half of 8 cm), while the maximum distance of a rectangle's diagonal (64 + 144) is ^{1 2} cm is approximately (14.5 cm).

In a further embodiment, the pattern or its light beams may experience a color change, for example, if the primary sensor has detected or recognized or not recognized the biometric feature.

In the following, further specific features of a device according to the invention are described, which are designed specifically for detecting a vein pattern, in particular the vein pattern of the human hand. Although the hand vein structure, because of its very high discriminability, has a high efficiency in detecting individual persons, it may still cause problems with the infrared images when background radiation of the environment leads to a strong background noise of the sensor signal. This problem arises in particular in the outdoor use of a Handvenensensors, for example, next to a building entrance. A possible source of background radiation interfering with the detection of the vein structure would be solar radiation in this case. A further object of the present invention is therefore to minimize interference of the measurement signal due to background radiation by a suitable embodiment of the detection device. According to the invention, a minimization of the background noise is achieved in that the housing has a shading section, which extends starting from the radiation-receiving surface of the sensor such that it at least partially shields the sensor against electromagnetic radiation falling on the housing. For this purpose, the shading section need not be transparent to electromagnetic radiation in the frequency range detected by the sensor. By this projection of the housing, the sensor surface is shielded in particular against stray side radiation.

The sensor is a technical component that can detect electromagnetic radiation in a defined frequency range. Since a vein structure is to be detected, which emits heat radiation in the infrared range, the detected frequency range is therefore the infrared range. For receiving incident infrared radiation, the sensor has a surface which absorbs this radiation as completely as possible. The infrared radiation incident on this surface constitutes the input signal and is converted by the sensor into an electrical output signal comprising information about the two-dimensional intensity pattern of incident infrared radiation on the surface and thus the vein structure causing this intensity pattern of infrared radiation.

The transparent portion of the housing is a portion that is transparent to infrared radiation. In this case, this section typically consists of a different material, or a different combination of materials than the rest of the housing, the invention is at least partially impermeable to infrared radiation in the form of Abschattungsabschnittes. In the simplest case, the transparent portion simply consists of a recess in the housing, so that it is permeable to electromagnetic radiation in each frequency range and in particular for those in the infrared range. However, the transparent section can also consist, for example, of transparent quartz glass for infrared radiation.

It is recommended that the shading section protrude with respect to the sensor surface by a height H = α x D vertically above the plane E defined by the sensor surface. Here, D is the maximum distance from the highest point of the shading section across the plane E to an edge of the sensor surface. An advantageous shielding with a simultaneously compact design of the device is achieved, as has been shown, when α is between 0.35 and 0.65, preferably between 0.4 and 0.6 and most preferably between 0.45 and 0.55 , In order to keep the section of the palm captured by the sensor surface, despite the shielding, in a size dimension that is advantageous for the recognition, it is recommended that the sensor surface be enclosed by flat inner surfaces of the shading section of the housing. In this case, the shading section of the housing should expand starting from the sensor surface in the shape of a truncated pyramid. In an alternative, likewise efficient embodiment, the shading section expands outward from the sensor surface in the manner of a truncated cone. It is particularly advantageous if the sensor surface enclosing the inner surfaces of the shading portion of the housing with the plane E of the Sen sororoberfläche an angle of 30 ° to 60 °, preferably from 40 ° to 50 ° and most preferably include 45 °.

An additional reduction of the background radiation, in particular of the solar radiation, can be achieved in that the sensor surface in the mounted state of the device on a holding element essentially faces the ground. Due to this orientation away from the main source of interference outside buildings, i. the sun, the intensity of the interference signals can be significantly reduced.

It has proved to be advantageous for the detection of venous structures, when the Sen sororoberfläche in the assembled state of the device on a holding element with a Lot a Wnkel of 90 ° to 45 °, preferably from 80 ° to 55 ° and best of 70 ° to 65 °.

For the practical implementation of the present invention, it is recommended that the device for the projection of the electromagnetic radiation pattern generate light beams in the visible frequency range. Due to the reflection of the light rays on the palm of the hand, the projected radiation pattern can easily be recognized by the human eye.

In this case, the device for projection of the optical pattern should be arranged and configured such that the light beams emanating from it generate a characteristic electromagnetic radiation pattern in a distance which is advantageous for the reception of a vein structure. This radiation pattern should be different from the pattern produced at other distances for the naked human eye. Thus, as soon as the desired characteristic radiation pattern has settled, for example, on the palm of her hand, the person to be identified knows that her hand is in the correct position for the measurement. Such a radiation pattern can be realized particularly simply by the fact that the light beams emanating from the device for projection intersect in front of the sensor surface in a maximum of three or preferably only one common point in the space. If the point of intersection of the light beams is at a distance to the sensor surface which is preferred for the measurement, then characterized the desired radiation pattern by an easily recognizable minimum number of projected points. In the simplest case, this is then a single point.

In this case, the device for pattern generation is ideally oriented such that the characteristic electromagnetic radiation pattern to be generated at the desired distance is located in front of the sensor surface in the region of a normal from the center of gravity of the sensor surface. As a result, even in the case of only a single point of intersection, a centered alignment of the hand in front of the sensor surface can be easily achieved. The device for the projection of the electromagnetic radiation pattern in the visible frequency range can be provided laterally next to the sensor surface. For a compact design of the device for non-contact detection of hand vein structures, it is advisable to install the device for the projection of an electromagnetic radiation pattern in the visible frequency range on the housing.

In order to be able to recognize, if necessary, excessive pivoting of the hand from a plane parallel to the sensor surface, the most symmetrical arrangement of devices for the projection of the electromagnetic radiation pattern in the visible frequency range is recommended. Thus, it can be ensured that the projected pattern changes, regardless of which direction the hand is pivoted out of the parallel plane. Therefore, it is advantageous if a plurality of devices along the circumference of the sensor surface are arranged distributed at approximately equal angular intervals around the center of gravity of the sensor surface.

A further advantage is when the device for the projection of the electromagnetic radiation pattern in the visible frequency range comprises an optical collimator device. By using collimators, the spread of the light beams can be reduced, which makes the projected radiation pattern sharper and the distance determination more precise.

A device according to the invention for contactless detection of palm vein structures can be produced in a particularly simple, cost-effective and low-maintenance manner if the device for projecting the electromagnetic radiation pattern in the visible frequency range is a light-emitting diode.

Further advantages, features and applications of the present invention will become apparent from the following description of a preferred embodiment and the accompanying figures. Show it:

FIG. 1 shows a palm vein scanner with a palm contour indicated schematically before it, FIG. 2 shows an exemplary beam path for generating a light beam pattern,

FIG. 3 shows the desired palm position with respect to the pattern;

Figure 4 shows another variant with means for generating light rays, which are independent of the housing of the Handvenensensors.

5 shows a device according to the invention for non-contact venous structure detection, FIG. 6 shows detailed views of the shading section of the device from FIG. 1,

FIG. 7 shows a device according to the invention in the assembled state,

8 shows a device with exemplary radiation pattern and

Figure 9 shows a preferred arrangement of a hand relative to the device according to the invention.

FIG. 1 shows a housing 10 in which a sensor 1 is located, which presents a sensor surface 2 on the front surface of the housing 10. The sensor 1 is an infrared sensor which is capable of detecting a pattern formed by the veins of a hand 3, which can be evaluated by means of a corresponding evaluation device and compared with stored patterns.

In the vicinity of the sensor surface 2 can be seen in the housing a plurality of openings or holes 4, from which, as shown schematically in Figure 2, converging light beams 5, which project on the sensor surface 2 facing the inner surface of the hand 3, a specific pattern and all cross together in a crossing point 7.

As can be seen with reference to FIG. 2, in which the hand has been omitted and the light beams 5 emanating from the bores 4 are reproduced schematically in the form of long thin cylinders, the light beams directed in FIG. 2 generally produce a pattern of 4 points appear on the housing 10 facing the palm of the hand as bright spots. The light beams 5 preferably have a blue hue in order not to disturb the infrared measurement of the hand veins as such. However, the four light beams 5 are aligned so that they intersect at a point 7 located at a distance d to the sensor surface 2 level 6. Thus, if the palm of the hand is held just in front of the sensor surface 2 at a distance d, only a single and substantially circular light blue spot will be projected onto the palm, while one point will change as the distance to the sensor surface 2 changes From the one, central and roughly circular light spot at the desired distance d, first a deformation in the direction of a rectangular spot occurs and then several (eg 4) separate light spots or light spots form on the palm of the hand.

The four rays of light emanating from points or holes that lie on the extended diagonal of the sensor surface and at the same distance from the center of the sensor surface are generally sufficient to generate the corresponding pattern. In the embodiments, however, further holes for the exit of corresponding light beams are shown, which are respectively assigned to the sides or edges of the sensor surface in the middle.

The light beams could also emanate from these openings or light sources and they could also be provided in addition to the light beams 5 already shown and intersect at the same point 7 in which the illustrated beams 5 intersect.

The sensor surface 2 may be, for example, specularly or partially specular, so that the user can easily recognize whether a corresponding single point of light forms on his palm, or if several separate points of light or a larger, consumed light spot have formed, from which the User can recognize that he still has to change the distance therefrom to the sensor surface 2 something, whether to detect the smallest possible and circular as possible light spot on his hand, so that recorded by the sensor 1 recorded and registered or compared with stored patterns can be.

The distance d between the plane 6 with the point of intersection 7 of the light beams and the sensor surface 2 is in a preferred variant about 5 cm, so that the user can keep his hand 3 at a considerable distance from the housing 10 and to the sensor surface 2 and the measurement is thus completely contactless.

It is understood that the light rays 5 could in principle also generate any other pattern on a palm or other surface moving together with the palm, with a particular characteristic pattern forming at the desired distance d, for example is given by means of a display board. The variant shown, however, shows a particularly simple and intuitively fast pattern to be detected in the form of a single, circular as possible light spot, which widens when changing the distance in the direction of the corners of a square surrounding the light spot and finally dissolves into four separate points. Such a light spot is particularly easy to identify.

Of course, it is equally possible that the corresponding light rays do not impinge on the palm of the hand from the side of the sensor surface 2, but impinge, for example, on the back of the hand from the opposite side. In this case, the user could adjust the distance of the hand to the sensor surface 2 by observing the pattern on the back of the palm. However, this would require additional components half of the actual sensor housing require and the arrangement of the light sources or on the housing 10 to the sensor 1 around is preferred. If the sensor surface 2, for example, 3 x 3 cm ² and the light sources or LEDs in the corner regions of the sensor surface 2 is a square of z. B. 5 x 5 cm ² span, then the diagonally opposite light beams 5 intersect at an angle of about 70 ° and the adjacent light beams 5 intersect at an angle of about 50 °. These cut angles allow sufficient focusing at the desired 5 cm spacing to a single, substantially circular spot of light.

It can be used as light sources on the one hand laser diodes that produce a very finely focused beam, but it is also possible to use simple light emitting diodes and to bundle the light with appropriate optical aids. For example, the light-emitting diodes may be arranged in tubular depressions 4, the walls of which reflect the light emanating from the LEDs and sufficiently bundle, whereby the light-emitting diodes themselves in the form of their transparent housing optical aids for generating a beam-like light beam, which also in the desired distance the formation of a sufficiently small and sharp light spot leads.

FIG. 3 again shows the housing 10 with the sensor 1 and the diagrammatically reproduced outlines of a hand 3, which is arranged so that the crossing point of the four illustrated light beams is imaged on the palm of the hand, which the user either in a reflective surface of the sensor 2 or but can recognize and control one of the mirror surfaces for this purpose, for example, edge surfaces 8, which surround the sensor surface 2.

FIG. 4 shows a further variant with a sensor 1 'in a corresponding housing, the light beams or the sources of the light beams however not being arranged in the housing of the sensor itself, but somewhere in its surroundings, but exactly so that the light from The pattern generated by the light beams or the pattern which forms at a desired distance from the sensor is located approximately centrally in front of the sensor surface 2.

By means of the device according to the invention and the corresponding method, it is possible to carry out an actually non-contact yet reliable and reliable detection of biometric features, for example the vein structure of a hand, by projecting a pattern onto the body part to be arranged at the correct distance with corresponding optical devices will allow the user to vary by changing the distance of the body part to the sensor surface 2 so as to set the correct distance. The system can then, for example, by changing the color of the light sources, such. B. the light-emitting diodes that generate the pattern, a successful measurement or authentication or even a failed authentication (for example, green light for "detected and authorized" and red for "not detected" or "unauthorized").

FIG. 5 shows a device according to the invention for non-contact venous structure detection. This consists of an infrared radiation-impermeable housing 13 with flat surfaces, which surrounds a sensor 1 1 with a sensor surface 12 for receiving electromagnetic radiation in the infrared range. In this case, the recess could be covered in an advantageous modification of the present embodiment for the protection of the sensor 1 1 with a transparent material for infrared radiation, for example quartz glass. The housing 13 has a shading section 17 which extends outgoing from the sensor surface 12 over the plane E defined by the sensor surface 12. At the same time, the shading section 17 shadows the sensor 11 at least partially against electromagnetic radiation 18 falling on the housing 13. The sensor surface 12 is bordered by flat inner surfaces 19 of the shading portion 17 of the housing 13. For mounting the device to a holding element, for example on a wall 17, the housing 13 has a flat rear side. The plane E includes with the back of the housing 13 at an acute angle. In the illustrated embodiment, the sensor surface 12 is square. The shading portion 17 is formed by webs, which on the receiving side on the plane E protruding and on all four sides of the square sensor surface 12 includes. In each case, a side surface of the webs is thus identical to one of the inner surfaces 19 of the shading portion 17 of the housing 13. The shading portion 17 widens here in a truncated pyramid outward. In the present case, due to the square configuration of the sensor surface 12, all four webs have identical shape and dimensions. In addition, opposing web burrs 23 each extend parallel to each other. In the detail view in FIG. 6a of the shading section 17 of the device from FIG. 15, it is clear that each of the housing webs has a triangular cross section in each case. The illustrated sectional view is perpendicular to two parallel web burrs 23. The vertical height of the webs above the plane E is denoted by H. The height can be given as H = ax D, where D is the maximum distance from the highest point of the shading section 17 vertically above E to an edge of the sensor surface 12 and a is a dimensionless factor. The exact determination of D in the case of a square sensor surface 12 with symmetrical shielding section 17, which is based on the sensor surface 12 pyramid-truncated is extended outwardly in the form of a figure, can be seen from above with reference to Figure 6a and the vertical view shown in Figure 6b. D designates according to the definition given above in this specific case, the direct distance between an intersection point of two web ridge and the opposite corner of the sensor surface. 2

An inventive device for non-contact detection of a vein structure is shown in Figure 7 in the assembled state on a holding element, here a wall 20. This wall 20 advantageously has a wall recess 21 below the device to allow a centered positioning of a hand 16 under the sensor 1 1. Without the recess 21 in the wall 20, the housing 13 would have to be designed in such a way that a sufficient distance of the sensor 11 to the wall 20 is ensured, so that there is sufficient space for a complete positioning, for example, of a hand 16 under the sensor 11 , In this case, however, the device would have to be dimensioned significantly larger, which may prove to be disadvantageous from a practical, financial and aesthetic point of view. Alternatively, the angle of inclination of the sensor surface 12 to the back of the housing 13 would have to be sharpened. However, this would lead to problems with the shadowing of the sensor surface 12, since more disturbing background radiation could be incident on the sensor surface 12 laterally. The arrow 18 indicates the direction of incidence of the sun's rays, here by way of example perpendicularly from above. It can be seen that the sensor surface 12 of the device is oriented approximately completely away from the incident sunrays 18 in the illustrated embodiment. As a result, it can be ensured that hardly any solar radiation 18 directly impinges on the sensor surface 12. Stray radiation, which is reflected, for example, from the ground, is shielded by the shading portion 17 of the housing 13. In FIG. 8, the device from FIG. 6 can be seen mounted on a wall 20 in the mounted state. By way of example, this figure shows the radiation pattern 15 generated by a device for projecting an electromagnetic radiation pattern in the visible frequency range, wherein the generated individual beams intersect at a fixed point of intersection 22 which has a perpendicular distance to the sensor surface 12 required for the recognition of the vein structure , Thus, the radiation pattern at all distances except the preferred one consists of several, in the case shown four points.

A hand 16 in a preferred position relative to the sensor surface 12 is shown in FIG. The hand 16 is located exactly at the intersection 21 of the beams 15 and thus in an advantageous for detection vertical distance to the sensor surface 12. The perceived in this position by the person to be recognized radiation pattern 15 on her hand surface is a single point 21, which should be located substantially in the middle of the palm of the hand. As soon as the hand 16 is moved out of this position, it disintegrates the hand 16 projected radiation patterns from a single point 21 back into multiple points. As a result, the person to be identified knows that his hand 16 is located in a distance which is not suitable for detecting the vein structure or in a disadvantageous orientation relative to the sensor 11.

For purposes of the original disclosure, it is to be understood that all such features as will become apparent to those skilled in the art from the present description, drawings and dependent claims, even though they have been specifically described only in connection with certain further features, both individually and in any combination with other features or feature groups disclosed herein, unless this has been expressly excluded or technical conditions make such combinations impossible or pointless. On the comprehensive, explicit representation of all conceivable combinations of features and the emphasis on the independence of the individual features of each other is here omitted only for the sake of brevity and readability of the description.

LIST OF REFERENCE NUMBERS

1/171 1 sensor

2/12 sensor surface

3 hand

4 hole

5 beams of light

6 level

7 crossing point

8 border areas

10/13 housing

14 projection device

15 radiation pattern

16 hand

17 shading section

18 background radiation

19 inner surface

20 wall

21 wall recess

22 intersection

23 bridge ridge

E level

H height

d / D distance

Claims

P a n t a n s p r e c h e

1. A device for detecting biometric features of body parts, comprising a biometric sensor (1) receiving housing (10), which a sensor surface (2) pre-

5 sent, the non-contact biometric features of a distance in front of the sensor surface arranged body part (3) can detect, characterized in that means for projecting a with the distance (d) to the sensor surface (2) changing optical pattern on one together with the body part (3) movable surface (3a) are provided.

10

2. Apparatus for detecting biometric features of body parts according to claim 1, characterized in that the means for projection of the optical pattern are provided adjacent to the sensor surface.

153. Device for detecting biometric features of body parts according to one of the preceding claims, characterized in that the means for projection of the optical pattern are provided on the housing.

4. An apparatus for detecting biometric features of body parts according to one of the preceding 0 henden claims, characterized in that the means for projection of the optical pattern along the circumference of the sensor surface and at a distance therefrom are provided

5. An apparatus for detecting biometric features of body parts according to any one of vorste- 5 Henden claims, characterized in that the means for projecting the optical pattern along the circumference of the sensor surface are arranged distributed at approximately equal angular intervals around the center of the sensor surface.

6. Apparatus for detecting biometric features of body parts according to any one of the preceding claims, characterized in that the means for projecting the optical pattern each generate a light beam.

Device for detecting biometric features of body parts according to one of the preceding claims, characterized in that the means for projection of the optical pattern comprise optical collimator means. Device for detecting biometric features of body parts according to one of the preceding claims, characterized in that the means for projecting the optical pattern are light-emitting diodes.

Device for detecting biometric features of body parts according to one of the preceding claims, characterized in that the means for projection of the optical pattern are respectively associated with the corners and centers of the sides of the rectangle next.

Apparatus for detecting biometric features of body parts according to any one of the preceding claims, characterized in that the means for projection of the optical pattern are arranged and configured such that the light beams emanating from you produce a characteristic pattern in a distance desired for the acquisition of a biometric feature in that it differs from the pattern produced at other distances for the naked human eye

A method for non-contact detection of biometric features of body parts, wherein a body part is presented at a distance from a sensor surface for detection by the sensor, characterized in that for determining a suitable detection distance, an optical pattern is projected into the space in front of the sensor surface that changes with changed the distance from the sensor surface

Method for the non-contact detection of biometric features of body parts according to claim 1 1, characterized in that the pattern is formed by a plurality of light beams emanating from different points.

Method for non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that the pattern is formed by a plurality of intersecting light beams.

Method for the non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that the light beams are aligned such that at the desired detection distance a pattern different from the patterns at other distances with the naked eye is produced.

Method for the non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that the light beams are reflected in such a way, that is to say they are of a very high quality Detection distance characteristic pattern is located in the region of a normal from the center of the sensor surface normal in front of the sensor surface

Method for non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that the beams are aligned so that they intersect in a maximum of three different spatial points.

Method for non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that the beams are aligned so that they intersect at a single point in space.

Method for non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that at least 3, preferably 8 light beams are used which emanate from different points of the surroundings of the sensor and intersect at a common point in space.

Method for non-contact detection of biometric features of body parts according to one of the preceding claims, characterized in that each of the light beams is generated by a respective light emitting diode, in particular by a respective laser diode.

Device according to one of claims 1 to 1 1, designed for non-contact detection of a vein structure with a sensor (1) for measuring electromagnetic radiation in a fixed frequency range, which has a radiation receiving surface (2), a housing (3), the one for electromagnetic radiation in the fixed frequency range has transparent portion, and means (4) for projecting an electromagnetic radiation pattern (5) in the visible frequency range, which varies with the distance to the sensor (1),

wherein the sensor (1) is disposed in the housing (3) so that electromagnetic radiation in the predetermined frequency range through the transparent portion of the housing (3) on the receiving surface (2) of the sensor (1) falls and this in operation the device can detect the vein structure of a body part (6) which is positioned at a predefined distance in front of the sensor (1), the radiation pattern (5) being projected onto a surface movable with the body part (6),

characterized in that the housing (3) has a shading section (7) which extends starting from the radiation-receiving surface (2) of the sensor (1) such that it at least partially faces the sensor (1) on the housing ( 3) falling electromagnetic radiation (8) shaded.

21. The device according to claim 20, characterized in that the shading section (4) on the receiving side by a height H = ax D perpendicularly protrudes beyond the plane E, which is determined by the electromagnetic radiation receiving surface (2) of the sensor (1), where D is the maximum distance from the highest point of the shading section (7) perpendicularly across E to an edge of the receiving surface (2), and a between 0.35 and 0.65, preferably between 0.4 and 0.6, and most preferably between 0.45 and 0.55.

22. Device according to one of claims 20 or 21, characterized in that the receiving surface (2) of the sensor (1) by flat inner surfaces (9) of the Abschattungsabschnitts (7) of the housing (3) is enclosed.

23. Device according to one of claims 20 - 22, characterized in that the Abschattungsabschnitt (7), starting from the receiving surface (2) of the sensor (1) widens pyramid-truncated outward.

24. The device according to any one of claims 20-23, characterized in that the shading section (7), starting from the receiving surface (2) of the sensor (1) widens frustoconically outward.

25. Device according to one of claims 20 to 24, characterized in that a the receiving surface (2) of the sensor (1) enclosing the inner surface (9) of the shading portion (7) of the housing (3) with the plane E an angle of 30 ° to 60 °, preferably from 40 ° to 50 ° and most preferably from 45 °.

26. The device according to any one of claims 20 -25, characterized in that the receiving surface (2) of the sensor (1) in the assembled state of the device on a holding element (10) is substantially facing the ground.

27. Device according to one of claims 20 to 26, characterized in that the receiving surface (2) of the sensor (1) in the assembled state of the device on a holding element (10) with a Lot an angle of 90 ° to 45 °, preferably from 80 ° to 55 ° and most preferably from 70 ° to 65 °.

28. The device according to claim 7, characterized in that the device (4) for the projection of the electromagnetic radiation pattern (5) in the visible frequency range is arranged and configured such that the light beams emanating from it in a for the Aufhof In order to obtain a vein structure advantageous distance, a characteristic electromagnetic radiation pattern (5) should be produced which differs from the electromagnetic radiation pattern (5) generated at other distances for the naked human eye. 29. Device according to one of claims 20 to 28, characterized in that the means (4) for projecting the electromagnetic radiation pattern (5) in the visible frequency range laterally adjacent to the receiving surface (2) of the sensor (1) is provided.

30. Device according to one of claims 20 to 29, characterized in that the device for projection of the electromagnetic radiation pattern (5) in the visible frequency range on the housing (3) is provided.

31. Device according to one of claims 20 to 30, characterized in that a plurality of devices (4) for the projection of the electromagnetic radiation pattern (5) in the visible frequency range along the circumference of the receiving surface (2) of the sensor (1) approximately the same Angular distances are distributed around the center of gravity of the surface (2).

32. Device according to one of claims 20 to 31, characterized in that the means (4) for projection of the electromagnetic radiation pattern (5) in the visible frequency range comprises an optical collimator.

33. Device according to one of claims 20 to 32, characterized in that the means (4) for projecting the electromagnetic radiation pattern (5) in the visible frequency range comprises light-emitting diodes.