METHOD AND DEVICE FOR PERFORMING A CHECKING OF A PERSON BY MEANS OF INFRARED RADIATION AS WELL AS A MOTOR VEHICLE HAVING SAID DEVICE

Abstract

A method for performing a checking of a person, such as a vehicle passenger, by way of infrared radiation involves determining the distance between a source of infrared radiation and the person by way of light according to a distance definition and setting the intensity of the infrared radiation in dependence on the distance as determined.

Claims

1. A method for performing a checking of a person, by infrared light, comprising: determining a distance between a source of infrared radiation and the person by way of light according to a distance definition, wherein the intensity of the infrared radiation is set in dependence on the distance as determined.

2. The method according to claim 1, wherein a device having the source of infrared radiation further comprises a light source and an optical camera, wherein the light source emits light pulses and the optical camera detects light of the light pulses reflected back from the person.

3. The method according to claim 2, wherein the light pulses have a duration not longer than 1/30 second.

4. The method according to claim 2, further comprising determining the distance, by the camera, based on a pupillary distance of eyes of the person on an image sensor device of the camera, a focal length of the camera, and a constant minimum pupillary distance.

5. The method according to claim 1, wherein the source of infrared radiation comprises a light-emitting diode, and wherein a maximum intensity of the infrared radiation of the light-emitting diode is less than 100 W/m.sup.2 per 20 mm of the distance.

6. A device for performing a checking of a person, comprising: an infrared source, a light source situated at the infrared source, an optical camera, and a controller, wherein the controller is configured to illuminate the light source on the person, wherein the controller is configured to determine the distance of the person from the infrared source according to a distance definition based on a picture taken by a camera, and wherein the controller is configured to establish the electric power of the infrared source and/or the radiation intensity put out by the infrared source based on the distance.

7. The device according to claim 6, wherein the light source comprises a vertical-cavity surface-emitting laser.

8. The device according to claim 6, wherein the device is disposed as part of a motor vehicle.

9. The device according to claim 6, further comprising a device for detecting a viewing direction of the person, wherein the motor vehicle comprises a head-up display configured to adjust based on the viewing direction, and/or wherein the device for performing the checking of the person is configured to check the driving ability of a vehicle driver, wherein the motor vehicle comprises a warning device and/or a device for providing an at least partial driving blockage, wherein the warning device and/or the device for providing the at least partial driving blockage are configured to be activated based on the driving ability of the vehicle driver.

10. The device according to claim 8, further comprising multiple units, each unit having an infrared source, the units being situated at different locations and/or different components of the motor vehicle.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0026] The FIGURE shows a device in relation to one person.

DETAILED DESCRIPTION

[0027] In the following exemplary embodiments, the components which are described for the embodiments each constitute individual features, to be considered independently of each other, and which also modify device and/or method described herein independently of each other. Therefore, the device and/or method may comprise combinations other than the presented combinations of features. Moreover, the described embodiments may also be amplified with other features of the already described features of the device and/or method described herein.

[0028] The device and/or method described herein is especially relevant to a motor vehicle, which is not shown in the FIGURE, but may be thought of as an external frame. In theory, the device and/or method may also be used outside of motor vehicles.

[0029] A vehicle passenger 1, here for example the vehicle driver, may be monitored by way of a device 2 for performing a checking of a person by way of infrared radiation. The device 2 may comprise an infrared unit 10 having an infrared radiation source 12 and an infrared sensor 14, the latter preferably in the form of an infrared camera.

[0030] In some embodiments, the device 2 may additionally be equipped with an optical unit 16. The optical unit 16 may a light source 18, which may be configured to beam light (electromagnetic radiation in the visible range) onto the person 1. In particular, the light source 18 may be a vertical-cavity surface-emitting laser (VCSEL) or also a light-emitting diode or multiple light-emitting diodes (e.g., six light-emitting diodes in an array). In some embodiments, the light source 18 emits pulsed light with a frequency of 1/60 second, and of such intensity that the vehicle passenger 1 does not or hardly notices the radiation.

[0031] The light source 18 may be used to determine the distance D between the device 2 (preferably in particular referred to the infrared source 12) and the eyes 24 of the vehicle passenger 1. The device 2 may also comprise in the optical unit 16 a camera having one or more lenses, the latter as a lens system. Only a single lens 20 is illustrated in the FIGURE. The camera may also comprise an optical sensor 22. The lens 20 or the lens system may have a focal length f. Accordingly, a picture of the person 1 may be taken in the plane of the optical sensor 22. The pupillary distance of the person 1 may become the distance PD.sub.img on the optical sensor. To determine the real pupillary distance PD.sub.real of the person 1 the following equation may be used:

PID.sub.read/PD.sub.img=(D+f)/f,

which may be approximated for a typically small f:

PD.sub.real/PD.sub.img=D/f.

[0032] Using the determined PD.sub.real, the distance D may be determined. In the method described herein, the real pupillary distance PD.sub.real may be known to the device 2.

[0033] For simplicity, however, one may start from a minimum pupillary distance PD.sub.min, which is typically 51 mm for women and 53 mm for men. The distance determined by the equation:

D.sub.min=PD.sub.min?f/PD.sub.img

can then be used here as D,

D:=D.sub.min,

for the purpose of the method described herein, to define the intensity of the infrared radiation emitted by the infrared source 12. (The distance D may be determined by the indicated formulas. The method may ultimately average the distance of the individual eyes 24 of the person 1.) The controlling of the light source 18 and corresponding evaluation of the measurements by the optical sensor 22, on the one hand, and the calculation of the distance D and the corresponding actuating of the infrared source 12 and also the later evaluation of the sensor measured values of the sensor 14, on the other hand, may be performed by a controller 30 in the device 2. Alternatively, a suitable controller may also be provided outside the device.

[0034] The controller 30 may ensure that the infrared source is operated such that the intensity (E.sub.IL) of the infrared radiation emitted remains less than 100 W/m.sup.2?D/20 mm. This corresponds to a standard for light-emitting diode light at longer emission times: the switched-off energy should be less than 100 W/m.sup.2 for a distance of 20 mm from the light source.

[0035] In general, the equation:

E.sub.IL<e?D/d,

is provided where e by default (standards or the like) is the maximum permissible energy for the distance d.

[0036] In some embodiments, such as the embodiment shown in the FIGURE, multiple devices 2, namely also the devices 2-2 and 2-3, may be included. If the devices are numbered consecutively (i=1, 2, 3 etc.), the respective distance D.sub.i may be determined, where D.sub.i is the distance of the i-th device from the eyes 24 of the person 1. It is then possible to coordinate the output of infrared radiation of the individual devices 2, 2-2, 2-3, for example by a master controller (where this task can be undertaken, for example, by the controller 30 of the device 2). It should then be the case that the maximum intensity E.sub.IL (i) put out by the i-th device or its infrared source 12 furnishes a contribution such that the sum is less than the above described limit, as shown by the equation:

?.sub.i=1.sup.NEIL(i)EILmax.

[0037] For example, given the same contribution of the infrared light arriving at the person 1 when there are N devices 2-1, 2-2, 2-3, . . . 2-N, it can be provided that:

E.sub.IL(i)<100 W/m.sup.2?1/20 mm?(D.sub.i)/?.sub.i=1.sup.NDi.

[0038] In summary, the embodiments provided show how a protection of the eyes against radiation energy may be provided by determination of the distance of optical sensors.

[0039] German patent application no. 10 2022 127175.7, filed Oct. 18, 2022, to which this application claims priority, is hereby incorporated herein by reference, in its entirety.

[0040] Aspects of the various embodiments described above can be combined to provide further embodiments. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.