DE102015008564A1 - Generation of structured light - Google Patents

Abstract

For energy-efficient generation of a point cloud, a device with a light source (1) and a light guide device (3), which has a light coupling point (4) optically coupled to the light source (1) and a light extraction point (5), is provided. The light-conducting device (3) has a fiber bundle (6) with a multiplicity of optical fibers (7), which runs from the light-coupling point (4) to the light-extraction point (5). All adjacent optical fibers (7) of the fiber bundle (6) have a first distance from one another at the light coupling point (4). At the light extraction point (5), the optical fibers (7) have a relation to the first larger second distance.

Description

The present invention relates to a device for producing structured light in the form of a pattern in a motor vehicle with a light source and a light guide, which has a light coupling point optically coupled to the light source and a Lichtauskoppelstelle. Moreover, the present invention relates to a system for detecting a gesture and / or movement in a motor vehicle with such a device.

In motor vehicles controls are increasingly carried out by means of gesture recognition. This is advantageous because the driver is then not distracted by the fact that he must visit controls.

Typically, a system used to detect gestures and movements includes a light source, a device such as a shadow mask for producing a patterned light in the form of a scatter plot, a camera for receiving a reflected light on a surface of an object, and an associated evaluation unit.

A special 3D camera technology is known by so-called "Kinect cameras", which are used for game consoles. To create a 3D image, such a Kinect camera uses an infrared projector and an infrared camera to generate depth data. Structured light forms the centerpiece of 3D space detection. The IR projector sends a defined pattern in the infrared range into the room. This is imperceptible to the human eye. The IR camera can record this pattern and pass it on. As the light source, a laser diode is used. The pattern for the structured light is generated by a pinhole mask having a plurality of holes. The basic structure of the point cloud is defined and known. The depth is calculated by triangulation against a known template (reference point cloud). The IR projector and the camera are at a defined distance from each other. If this cloud hits an uneven object, the distance between the dots and their position in the camera image are changed. The point cloud calculated from the deformation of the pattern makes it possible to triangulate depth distances between the points. This principle is in D. Scharstein and R. Szeliski (2003): "High Accuracy Stereo Depth Maps Using Structured Light", In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 195-202 explained in more detail.

Apertures or masks have the great disadvantage that a large part of the light output is absorbed by the mask and thus can not be used. This leads to a poor pattern generation efficiency.

Alternatively, pattern and point clouds can also be generated by means of diffractive optics placed in front of a light source. With these diffractive optics, although significantly more efficient patterns can be produced, however, these optics have significant disadvantages over the temperature range required in the motor vehicle. In particular, there is a wavelength drift above the temperature, which leads to a significant deterioration in the efficiency of the quality of the pattern.

In addition, from the document WO 2014/026918 A1 a light guide plate with decoupling elements known. Light sources are mounted on the edges of the light guide plate. The light is transported by total reflection inside the plate. By attached to the surface side of the light guide plate Lichtauskoppelelemente the light is coupled out at this surface side. Typical light output elements are printed patterns of white color, the roughening of the surface of the light guide plate or embossed refractive structures. Such light guide plates are used in particular for LC displays of computers, mobile phones and the like.

The object of the present invention is to provide a device for producing structured light, in which this generation can be carried out in a more energy-efficient manner.

According to the invention this object is achieved by a device according to claim 1 or claim 8 and by a system according to claim 9. Advantageous developments of the invention will become apparent from the dependent claims.

According to the invention, there is therefore provided a device for producing structured light in a motor vehicle having a first light source and a light guide device, which has a first light coupling point optically coupled to the first light source and a light extraction point, wherein the light guide means the first fiber bundle having a plurality of first optical fibers, which extends from the Lichteinkoppelstelle to the Lichtauskoppelstelle, all adjacent first optical fibers of the first fiber bundle at the Lichteinkoppelstelle have a first distance to each other, the adjacent first optical fibers of the first fiber bundle at the Lichtauskoppelstelle have a second distance, which is larger than the first distance.

Accordingly, in one embodiment, the optical fiber device comprises at least a first fiber bundle with a multiplicity of first optical fibers. They extend from the light coupling point to the light extraction point. At the geometric location of the light coupling, d. H. the Lichteinkoppelstelle, all adjacent first optical fibers of the first fiber bundle have a minimum possible first distance from each other. The first optical fibers are thus as close as possible to each other, d. H. Ideally, the optical fibers are arranged in contact with a first distance of 0 mm. In conventional round fibers, preferably each inner fiber is surrounded by six equally shaped fibers, resulting in a densest packing. So that the light emitted by the light source can be coupled into the fiber bundle with as little loss as possible, the distance between the optical fibers should be as minimal as possible.

The adjacent to the Lichteinkoppelstelle fibers are preferably adjacent to the Lichtauskoppelstelle. But there they have a certain second distance, which is greater than the first distance. The advantage of this device is that the entire coupled into the light guide light (except for minimal internal losses) also exits at the light extraction point and is used for pattern generation. This results in a very efficient pattern generation.

The optical fibers of each of the fiber bundles may have a diameter of less than 100 μm, in particular less than 50 μm. For example, they have a diameter of 30 microns. As a result, a multiplicity of optical fibers can be brought together at the coupling-in point to form a relatively small coupling point. Preferably, each fiber bundle has at least twenty individual optical fibers.

In an embodiment of the invention, moreover, a collimator device is arranged, with which the light emerging at the light extraction point can be collimated. The light emerging from the optical fibers is in this case aligned in parallel by the collimator device. This means that each individual light beam emerging from one of the many fibers is collimated, for example, to produce a point of predetermined size at a predetermined distance on an object.

In one embodiment, the second distance between adjacent first optical fibers is effected by second fibers. Preferably, the second fibers have the same cross-section as the first optical fibers, so that a regular structure of first and second optical fibers can result at the coupling-out point. The second distance is effected by the second fibers in combination with other elements such as filler or solely by the second fibers. The second fibers may be pure, if appropriate, optical fibers designed as dummy fibers, which are not used for light transmission, but only as a spacer. Optionally, additional spacers are used. Alternatively or in combination with the fibers, the second distance can be generated by filling material arranged between the first fibers, for example synthetic resin or plastic.

In a development, the second fibers are components of a second optical fiber bundle, which is part of the light guide device and has a second, different Lichteinkoppelstelle from the first and the Lichtauskoppelstelle, wherein the second Lichteinkoppelstelle is coupled to a second light source. The Lichteinkoppelstelle of the second fiber bundle thus differs from the Lichteinkoppelstelle the first fiber bundle, while the location of the light extraction of the two fiber bundles is the same. This is realized in particular in that the fiber bundles are interwoven at the location of the light extraction. For example, the first optical fibers and the second optical fibers adjoin one another alternately. At the light coupling point, the fibers of the second optical fiber bundle are at a distance from each other which is smaller than the distance at the coupling-out point.

In an additional refinement, the fibers are components of a third fiber bundle which is part of the light guide device and which has one of the first and second different, third Lichteinkoppelstelle and Lichtauskoppelstelle, wherein the third Lichteinkoppelstelle is coupled to a third light source. The second distance between adjacent first optical fibers is contributed by third conductive fibers (in addition to the second optical fibers). At the light coupling point, the fibers of the third optical fiber bundle have a distance from one another which is smaller than the distance at the coupling-out point. On the coupling-out side, the third fiber bundle is interwoven with the first and second fiber bundles, while the coupling-in points are spatially separated from one another. This principle of weaving the decoupling points can be continued for further fiber bundles.

If several light sources are used, they can be controlled by a control device, with which they can be activated with a time delay. This means that the individual fiber bundles are traversed by light in succession. After each fiber bundle generates its own sub-point cloud, the sub-point clouds can be generated in a time-shifted manner or one after the other to improve the resolution.

In an alternative embodiment of the device for producing structured light, the second distance of the optical fibers at the light extraction point is effected by a shadow mask, in whose holes the first optical fibers open. This means that the optical fibers are held at their exit end by the shadow mask. The shadow mask then gives the individual optical fibers the desired distance. Thus, almost any second distances, which may also be different from the diameter of the optical fibers, can be realized. In addition, the distances between the fibers of the first, second, third or further optical fiber bundle to each other at the light extraction point through the shadow mask to effect. The shadow mask is part of the light guide. Alternatively, in the manufacturing process, the shadow mask effects the distances of the fiber by fixing the fibers at the exit point through the shadow mask, connecting the fibers by means of a filler in the fixed position, and thereafter removing the shadow mask.

According to the invention the above object is also achieved by a device for generating structured light with a light source and a light guide, which is optically coupled to the light source, the light guide having a light guide plate with a plurality of outcoupling elements, and on the decoupling a Kollimatoreinrichtung is arranged with the respectively emerging light of each decoupling element is collimated.

Instead of the fiber bundles, the light guide device here has a light guide plate with a large number of outcoupling elements. Such decoupling direct the light from the interior of the light guide plate on the flat side, d. H. with a directional component perpendicular to the main extension plane of the light guide plate, out of this. Preferably, the light guide plate has at least twenty such outcoupling elements.

Preferably, the invention provides a system for detecting a gesture and / or movement in a motor vehicle with an above-mentioned device for producing structured light. This system further comprises a camera for detecting the pattern of the structured light projected on the objects in the projection area and an evaluation device for determining the gesture and / or movement of the object from the point cloud determined on the basis of the reflection of the structured light. The pattern of the reflected structured light is thus detected on an object whose gesture or movement is to be reliably detected.

Conveniently, the evaluation device of the system is designed such that the gesture and / or movement can be calculated on the basis of a triangulation and a predetermined reference point cloud with respect to a reference image. This means that the individual points of the point cloud change the distance to each other when the object that is being irradiated point by point moves. As an alternative to triangulation, other methods such as time of flight could be measured to obtain depth data. For this, the camera would have to ensure a corresponding point resolution.

The present invention will now be explained in more detail with reference to the accompanying drawings, in which:

1 the basic structure of a device according to the invention for generating structured light;

2 a decoupling point with fiber spacers;

3 a side view of the light guide of 2 ;

4 a decoupling point with mask;

5 a side view of a light guide according to 4 ;

6 a decoupling point of a light guide with three fiber bundles;

7 a fiber optic overall system with a decoupling point according to 6 ;

8th a structured light generating device having a light guiding plate; and

9 a system for gesture recognition with the fiber optic system of 7 ,

The embodiments described in more detail below represent preferred embodiments of the present invention. The individual features can be realized not only in the described feature combinations, but also in isolation or other combinations.

Especially in a motor vehicle, but possibly also in other devices, a control by means of gesture recognition is to be performed. This can be done in 1 reproduced device for generating structured light in the form of a cloud of points can be used. This device has a first light source 1 and optional optics 2 with collimator for light coupling the light of the light source 1 in a light guide 3 , The light guide 3 has a coupling point 4 into which the light is through the optics 2 is coupled. Below the input side of the light guide 3 is in 1 an end view of Einkoppelstelle 4 shown. In addition, has the light-conducting device 3 a decoupling point 5 whose frontal view is in 1 also below the coupling-out side of the light-conducting device 3 is shown. Between the coupling point 4 and the decoupling point 5 runs a fiber bundle 6 , This consists of a large number of individual optical fibers 7 , Preferably, the number of optical fibers is 7 per fiber bundle 6 at least twenty. The graphics in 1 are accordingly to be seen purely schematically. The diameter of a fiber is favorably less than 100 microns and is for example at 30 microns.

Out 1 it can be seen that the fiber bundle 6 the light guide 3 from the coupling point 4 to the decoupling point 5 is widened. This means that the distance between adjacent optical fibers 7 at the coupling point 4 a first distance and at the decoupling point 5 has a second distance, wherein the second distance is greater than the first distance. The distance always refers to two adjacent optical fibers 7 , While the distance of the optical fibers 7 at the coupling point 4 is preferably minimal, ie zero, have the adjacent optical fibers 7 at the decoupling point 5 a larger, ie non-zero, distance. The circumference of the fiber bundle is thus at the decoupling point 5 greater than at the coupling point 4 ,

From the decoupling point 5 the light becomes a projection system 8th guided. This has, for example, a collimator 9 and optionally a projection optics 10 , Through the collimator, the divergent rays of the decoupling point 5 preferably converted into parallel rays. The projection optics 10 ensures that the parallel beams are deflected in different directions as desired. Thus, the size of a dot pattern or a point cloud whose principal structure through the decoupling point 5 is given, can be varied.

With this construction of 1 becomes the radiated optical power of the light source 1 distributed extremely efficiently to the sample points to be generated. The light is lost as much as possible through the optics 2 , which optionally also includes a collimator, coupled into the fiber bundle. The division of the light into the individual, preferably parallel light beams or points on an illuminated object takes place while avoiding absorption by the widening of a fiber bundle 6 and the optional projection system 8th ,

As a light source, for example, an LED, a laser, a VCSEL, a VCSEL array or the like in question. To losses during coupling in the light guide 3 To avoid the light from the light source is preferably through the optics 2 on the geometry of the coupling point 4 collimated.

At the decoupling point 5 can the distance between the individual optical fibers 7 , for example, according to 2 by so-called "dummy fibers" 11 getting produced. There are the individual optical fibers 7 together with the dummy fibers 11 preferably also packed as densely as the optical fibers 7 alone at the coupling point 4 , This means that each fiber is surrounded by six neighboring fibers of the same diameter. Optionally, the dummy fibers have 11 and the optical fibers 7 So the same diameter. But you can also have different diameters. For the same diameter, the screening corresponds to the fiber diameter. The screening of the fiber end faces at the decoupling point 5 but does not have to be hexagonal centered or triangular. It can also be square, for example. Each fiber-optic fiber 7 Transports light to a respective pattern point and assigns it to a defined geometric position. The dummy fibers, which serve as spacers, may also be made of the same material as the optical fibers, but they are not used here for light conduction. However, fibers which have no light-conducting properties can also be used as dummy fibers. To clarify the distance function of the dummy fibers 11 is a side view of the light guide 3 in 3 shown schematically. Between every two optical fibers 7 Here is symbolically a dummy fiber 11 at the decoupling point 5 ,

The 4 and 5 show an example in which the screening of the optical fibers 7 at the decoupling point 5 does not have to correspond to the fiber diameter of the optical fibers. At the decoupling point 5 become the optical fibers 7 for example through a shadow mask 12 fixed by threading the fibers through the mask. Optionally, a casting is done with a filler material 13 , especially plastic. Finally, the optical fibers can be cut off at the decoupling point and the decoupling point then polished.

Due to the large distances in a fiber system with dummy fibers, which are used only as a spacer, the lateral resolution for z. B. image processing systems relatively poor. In order to significantly improve the lateral resolution, the dummy fibers can be partially or completely also designed as light-conducting fibers and connected to one or more lighting units.

Such a system with improved lateral resolution is in the 6 and 7 shown. 6 shows a decoupling point 5 in which the fibers, as in the example of 2 , are densely packed and preferably have the distance zero to the respective neighbors. Fibers of a first fiber bundle are in 6 marked with "a". This fiber bundle system "a" corresponds for example to that of the light-conducting fibers 7 of the 2 and 3 , Now, however, the remaining fibers are not only used for spacing the "a" fibers, but also for light conduction. Specifically, in the example of 6 and 7 three such systems of 1 interwoven. The complete fiber optic system of 7 So has three light sources 1 . 1' and 1'' , Accordingly, it also has three collimators or optics 2 . 2 ' and 2 '' to the light of each light source for the coupling point 4 the light guide 3 to collimate or align in parallel.

The light guide 3 owns here three fiber bundles 6 . 6 ' and 6 '' , While the individual fiber bundles 6 . 6 ' and 6 '' at the coupling point 4 are separated from each other, they are at the decoupling point 5 interwoven. The arrangement of the individual optical fibers of the three fiber bundles, 6 . 6 ' and 6 '' at the decoupling point 5 , the frontal view of 6 correspond. Each optical fiber "a" originates from the fiber bundle 6 , each optical fiber "b" from the fiber bundle 6 ' and each optical fiber "c" from the fiber bundle 6 '' , The number of individual optical fibers per fiber bundle can be the same, but it can, as the example of 6 also shows different. Preferably, the distribution is chosen such that the fibers of each bundle are evenly distributed over the total area, so that each individual pattern generation system 1 . 2 . 6 respectively 1' . 2 ' . 6 ' respectively 1'' . 2 '' . 6 '' can produce a uniform cloud of points over a given area. For this purpose, the output side is behind the light guide 3 still the projection system 8th that has the function as in the example of 1 has.

Basically, three light pattern generation systems need not be interwoven. Rather, it can also be two, four or more. With these nested or interwoven pattern generation systems, it is possible to sequentially project several patterns in time and to capture them as partial images. These staggered partial images can be viewed through a camera 14 (see. 9 ) and a computing unit or evaluation unit connected thereto 15 evaluated in a suitable manner and the results are then superimposed accordingly. Thus, the lateral resolution for z. B. image processing systems, whereby the relative movement of an object 16 can be better determined.

8th shows a further embodiment of an inventive device for generating structured light in the form of a point cloud. The light source 1 is here bar-shaped, as well as the optical system 2 with optional collimator. In contrast to the preceding embodiments, the light-guiding device comprises 3 here no fiber bundles, but a light guide plate 17 , While the light on a narrow front 18 the light guide plate 17 by means of the optical system 2 it is coupled by decoupling elements 19 on a large side surface 20 the light guide plate 17 , preferably substantially perpendicular, to this side surface 20 decoupled. After decoupling, the respective light beam has (preferably more than twenty over the entire side surface 20 distributed) a certain divergence. Therefore, the light rays are transmitted through the projection system 8th as in the example of 1 , further formed. This projection system 8th optionally has a collimator here again 9 and an optical system 10 for pattern widening.

For the generation of a desired pattern, the decoupling elements 19 according to the pattern over the side surface 20 the light guide plate 17 arranged. In order to achieve a uniform intensity distribution for all decoupled light beams, light may also be present on several or all narrow sides of the light guide plate 17 be coupled.

9 finally shows a system for detecting a gesture or a movement that can also be used in a vehicle. Symbolic of any pattern generation system is in 9 that of 7 selected. One of them on an object 16 generated points 21 is reflected by the camera 14 recorded and by the evaluation device 15 further processed for gesture recognition. Now moves the object 16 to a new object position 16 ' , so the point wanders 21 to the new position 21 ' , This in turn is done by the camera 14 and the evaluation device 15 registered. From this change in the position of the point 21 can by triangulation corresponding position data of the object 16 be gained, as the distance between pattern generation system and camera 14 is known. Advantageously, by the pattern generation system, a point cloud or a dot pattern with the points 21 produced very energy efficient.

LIST OF REFERENCE NUMBERS

1, 1 ', 1' '

light source

2, 2 ', 2' '

optics

3

light guide

4

coupling point

5

decoupling point

6, 6 ', 6' '

fiber bundles

7

optical fibers

8th

projection system

9

collimator

10

projection optics

11

Dummy Fiber

12

shadow mask

13

filling material

14

camera

15

evaluation

16, 16 '

object

17

Light guide plate

18

front

19

outcoupling

20

side surface

21, 21 '

Point

a

first optical fiber system

b

second optical fiber system

c

third optical fiber system

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2014/026918 A1 [0007]

Cited non-patent literature

• D. Scharstein and R. Szeliski (2003): "High Accuracy Stereo Depth Maps Using Structured Light", In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pp. 195-202 [0004]

Claims (10)

Device for producing structured light in a motor vehicle with - a first light source ( 1 ) and - a light-conducting device ( 3 ), which is optically connected to the first light source ( 1 ) coupled first Lichteinkoppelstelle ( 4 ) and a light extraction point ( 5 ), characterized in that - the light-conducting device ( 3 ) a first fiber bundle ( 6 ) with a plurality of first optical fibers ( 7 ), which is from the first Lichteinkoppelstelle ( 4 ) to the light extraction point ( 5 ), - all adjacent first optical fibers ( 7 ) of the first fiber bundle ( 6 ) at the first light coupling point ( 4 ) have a first distance to each other, - the adjacent first optical fibers ( 7 ) of the first fiber bundle ( 6 ) at the light extraction point ( 5 ) have a second distance greater than the first distance Device according to claim 1, characterized in that at the light extraction point ( 5 ) a collimator device ( 9 ) is arranged, with which the at the Lichtauskoppelstelle ( 5 ) emerging light is collimated. Device according to one of claims 1 or 2, characterized in that the second distance between adjacent first optical fibers ( 7 ) is effected by fibers. Apparatus according to claim 3, characterized in that the fibers components of a second optical fiber bundle ( 6 ' ), which part of the light guide device ( 3 ) and one of the first different, second Lichteinkoppelstelle and the Lichtauskoppelstelle ( 5 ), wherein the second light coupling point to a second light source ( 1' ) is coupled. Device according to one of claims 3 or 4, characterized in that the fibers comprise components of a third fiber bundle ( 6 '' ), which part of the light guide device ( 3 ) and one of the first and second different, third Lichteinkoppelstelle and the Lichtauskoppelstelle ( 5 ), wherein the third light coupling point to a third light source ( 1'' ) is coupled. Device according to claim 4 or 5, characterized in that the light sources ( 1 . 1' . 1'' ) are driven by a control device, with which they are mutually activated with a time delay. Apparatus according to claim 1, characterized in that the second distance through a shadow mask ( 12 ), in whose holes the first optical fibers ( 7 ), causes. Device for producing structured light in a motor vehicle with a light source ( 1 ) and - a light-conducting device ( 3 ), which optically to the light source ( 1 ) is coupled, characterized in that - the light-conducting device ( 3 ) a light guide plate ( 17 ) with a plurality of decoupling elements ( 19 ), and - at decoupling elements ( 19 ) a collimator device ( 9 ) is arranged, with which the respective emerging light each output element ( 19 ) is collimatable. System for detecting a gesture and / or movement in a motor vehicle with a device according to one of the preceding claims for producing a structured light, with a camera ( 14 ) for detecting a reflection of the structured light and with an evaluation device ( 15 ) for determining the gesture and / or movement of an object from a point cloud determined on the basis of the reflection of the structured light. System according to claim 9, characterized in that the evaluation device is designed to calculate the gesture and / or movement on the basis of a triangulation and a predetermined reference point cloud.

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