EP4022883A1

EP4022883A1 - Camera device for generating an image of surroundings

Info

Publication number: EP4022883A1
Application number: EP20754254.9A
Authority: EP
Inventors: Tobias Moll
Original assignee: Audi AG
Current assignee: Audi AG
Priority date: 2019-08-29
Filing date: 2020-08-11
Publication date: 2022-07-06
Also published as: US20220272258A1; CN114009001B; US11758273B2; DE102019212988A1; WO2021037556A1; CN114009001A

Abstract

The invention relates to a camera device (10) with an enlarged or wide-angle field of view (FOV), of 165 degrees for example, for generating one or more images (U) of the surroundings simultaneously using only one image capturing device (12), such as an image sensor for example. For this purpose, the camera device (10) uses a deflecting unit (11), which is connected upstream of the image capturing device (12). The deflecting unit (11) has so-called holographic optical elements which are designed to divert or deflect light on the basis of deflecting structures (23, 24, 25, 26, 27, 28) of the elements so that the camera device (10) can capture the wide-angle field of view (FOV) without imaging errors on the resulting image(s). For this purpose, the deflecting structures (23, 20, 24, 25, 26, 27, 28) are designed to be wavelength-selective and/or angle-selective. The entire field of view (FOV) is thus divided into individual angular regions of incidence (T1, T2, T3) by virtue of the properties of the deflecting structures (23, 24, 25, 26, 27, 28).

Description

Camera device for generating an image of an environment

DESCRIPTION: The invention relates to a camera device for generating at least one image of an environment. The invention also relates to a motor vehicle with such a camera device.

A conventional camera or camera device, such as a photo or video camera, generally has an image sensor and an imaging optics arranged in front of it for generating an image of an environment. The imaging optics is also referred to as an objective and usually consists of a lens or a lens system with several lenses. It is used to bundle the light from the environment and thus to focus or deflect the light onto the image sensor, so that a desired object from the environment is sharply imaged on the image sensor. A design of the image sensor, in particular its dimensioning or sensor size, and / or a focal length of the lens define a field of view (FOV) and thus a viewing angle of the camera. The field of view here means the area in the environment that can be captured by the camera and mapped onto the image sensor.

From US 2008/0180537 A1, for example, a camera system is known which has an orientation device by means of which a user can identify the field of view of a camera.

Furthermore, US 2018/0338089 A1 discloses a camera module for normal and infrared photography. In order to improve the quality of a resulting image of the environment, it is provided here that a visual Angle, i.e. the field of view of the camera module is restricted during normal photography.

For virtual reality or augmented reality applications as well as in motor vehicles, however, wide-angle camera systems, in particular cameras with a field of view or angle of view greater than 60 degrees, are increasingly required. As a result, the largest possible area in the environment is to be covered or recorded. So-called wide-angle lenses are often used for this. However, these have the disadvantage that they are relatively large and have a pronouncedly curved lens. This can lead to unwanted reflections of the light from the environment on the lens, especially at the edges of the field of view, which would restrict the field of view. In addition, this often results in strong optical distortions, for example barrel distortion or chromatic aberration, which can lead to image errors in the resulting image.

As an alternative to a camera with a wide-angle lens, several individual cameras could also be used to capture the largest possible field of view. These can be arranged next to one another, so that their fields of view adjoin one another and when the individual images or individual recordings are put together, an image with a large field of vision results. The disadvantage of this method, however, is that there must be a plurality of installation locations for the individual cameras. In addition, individual images must be synchronized or recorded at exactly the same time so that the enlarged field of view can be captured. The use of many individual cameras also increases the costs of such a camera system.

The object of the present invention is to provide a camera device which enables an inexpensive recording of an image of an environment with an enlarged field of view. This object is achieved by the subjects of the independent patent claims. Advantageous developments of the invention are disclosed by the dependent claims, the following description and the figures.

The invention is based on the knowledge that a corresponding camera device can be provided by means of holographic-optical elements (HOE). A HOE can namely fully or partially simulate the optical function of a conventional lens, i.e. a lens system. That is, with the HOE, light from the surroundings to be imaged can be deflected or deflected in the opposite direction to the image capturing device, that is to say for example the image sensor. To deflect or redirect the light, an HOE has a deflection structure, for example in the form of an optical grating. HOEs have the advantage that, depending on the design of the deflection structure, they can be designed selectively or sensitively for different wavelengths and / or different angle of incidence ranges. So they are angle-selective and / or wavelength-selective. The property of wavelength selectivity of HOEs is also known from JP 40 866 617 A, for example. In the present invention, two or more such HOEs, which are each selective for different angles of incidence areas, are used to enlarge the field of view of the camera device. The enlarged field of view of the camera device is thus made up of the angle of incidence areas, that is to say the individual areas of view of the HOEs. The production and function of an HOE is explained in more detail later.

To generate the at least one image of the surroundings, the camera device has a light-conducting medium, for example a plate or pane made of glass or plastic, which is designed as a light guide. A coupling-in region and a coupling-out region are arranged on the light-conducting medium, preferably along a direction of longitudinal extent of the light-conducting medium. The coupling-in area has at least two coupling-in deflection structures, that is to say for example two of the above-mentioned HOEs, each of which is designed to emit light of a predetermined spectral range falls from a given angle of incidence range from the environment onto the respective deflecting structure, to be coupled into the light guide medium. Each of the deflection structures is designed to be selective or sensitive with respect to a spectral range and angle of incidence range that are different from the other deflection structures. The light-conducting medium then takes on the function of forwarding the coupled-in light. The light-conducting medium is designed to transmit the coupled-in light from the coupling-in area to the coupling-out area by means of internal reflection. Analogously to the coupling-in area, the coupling-out area also has at least two decoupling deflection structures. The at least two outcoupling deflection structures are designed to decouple the light of the predetermined spectral range that is coupled in from each of the inward-coupling deflection structures and which falls on the respective outcoupling deflection structure from the light guide medium. Each of the deflecting structures to be coupled out is preferably assigned to one of the deflecting structures to be coupled in. That is, they only couple the deflecting structure assigned to it in each case. Correspondingly, the at least two outcoupling deflection structures are advantageously selective or sensitive to the same spectral ranges as the at least two in-coupling deflection structures.

The light-conducting medium with the coupling-in area and the coupling-out area can consequently be understood as a deflection unit for the light from the environment. The offset arrangement of the coupling-in region and the coupling-out region thus results in an offset of an optical axis of the coupled-in light and the coupled-out light.

The aforementioned image acquisition device is also provided for acquiring the light deflected by the deflection unit. This is arranged on the coupling-out area. The image acquisition device can be designed, for example, as an image sensor, such as a CCD or CMOS sensor. Alternatively, the image acquisition device can also be designed as a conventional camera with an objective. The deflection unit is thus connected upstream of the image capturing device. To capture the decoupled In terms of light, the image capturing device has at least two capturing areas. The at least two detection areas are in particular assigned to one of the at least two outcoupling deflection structures. Thus, each of these detection areas is designed to detect the light decoupled from in each case one of the outcoupling deflection structures, and the image detection device is designed to generate image data from the detected light. A separate image data record can therefore be generated by the image acquisition device for each of the acquisition areas. The image data or image data sets differ in their spectral range and angle of incidence ranges. The at least one desired image of the surroundings, that is to say one or more images of the surroundings, can then be generated or made available from these image data.

In summary, a camera device is proposed with which a wide-angle image or several individual images with different fields of view can be captured from an environment at the same time. The descriptive deflection unit can thus represent a type of wide-angle or multi-view special lens based on holographic-optical elements as imaging optics. The camera device for capturing the largest possible field of view can thus be provided in a particularly cost-effective manner.

The invention also includes embodiments which result in additional advantages.

In one embodiment it is provided that the camera device furthermore has a computing device which is designed to provide separate images from the generated image data. In other words, the deflection unit mentioned is designed as a multi-view lens. As a result, several recording areas or fields of view can be recorded with the camera device. An image of the environment is thus generated for each image data record. The images differ at least in part in their field of view. Thus, with only one camera device, that is to say in particular with only one image capturing device Little space requirement and inexpensive a camera device that can capture several recording areas (Multi View) or fields of view can be provided. The individual images can be provided as color images in accordance with their respective spectral range or as black-and-white images or gray-scale images.

In an additional or alternative embodiment, it is provided that the computing device of the camera device is designed to provide a common image of the surroundings from the generated image data. That is, the aforesaid deflection unit can form a wide-angle lens based on HOEs. The field of view of the camera device can be composed of the individual viewing areas that are provided by the angular selectivity of the deflection structures. The viewing areas, that is to say also the areas of the angle of incidence, can at least partially overlap. The image acquisition device can thus combine the various image data or image data sets that have been generated as a function of the angle of incidence ranges and different visual ranges in each case, and a common image of the surroundings can be calculated therefrom. The common image of the environment can preferably be provided as a black-and-white image or a grayscale image.

In the following embodiments, an embodiment of the steering structures from and thus also the production and function of HOEs is described in more detail.

One embodiment provides that at least one optical grating, in particular a holographic surface grating or a holographic volume grating, is provided as the respective deflection structure.

An optical grating, also called a diffraction grating, and its method of operation and manufacturing process is well known. In principle, an optical grating can be designed as at least partially periodic structures, so-called grating structures, in a substrate. By means of the grating structure, an optical grating can be achieved through the physical effect diffraction, as is known, for example, from mirrors, lenses or prisms. If light falls, that is, light rays fall on the optical grating, the incident light rays in particular fulfilling the Bragg equation, the light rays are bent or deflected by the optical grating. The light can thus be directed in particular by interference phenomena of the light beams diffracted by the optical grating. The deflection structure of the coupling-in area or the coupling-out area can accordingly also be referred to as a diffraction structure.

Preferably, an optical grating can be designed to be direction-selective or angle-selective with respect to the incident light. Thus, only light, in particular a portion of the light that falls onto an optical grating from a predetermined direction of incidence, for example at a predetermined angle, can be deflected. Light, in particular a portion of the light that falls onto the optical grating from a different direction, is preferably not deflected or, the less, the greater the difference from the predetermined direction of incidence. The portion of light which deviates from the predetermined direction of incidence or optimal direction of incidence can consequently preferably propagate unhindered through the substrate with the optical grating.

Additionally or alternatively, an optical grating can also be designed to be wavelength-selective or frequency-selective. Thus, only light, in particular a first portion of the light with a predetermined wavelength, can be deflected or diffracted by the optical grating at a specific diffraction angle. Light, in particular a second portion of the light with a wavelength other than the predetermined wavelength, is preferably not deflected, or the less the greater the difference from the predetermined wavelength. The second light component, which differs from the predetermined wavelength or optimum wavelength, can consequently preferably propagate unhindered through the substrate with the optical grating. In this way, for example, at least one monochromatic light component can be split off from polychromatic light which strikes the optical grating. The deflection effect is advantageous for the optimum wavelength maximum and falls to longer and shorter wavelengths, for example according to a Gaussian bell, or becomes weaker. In particular, the deflection effect only acts on a fraction of the visible light spectrum and / or in an angular range smaller than 90 degrees.

An optical grating can in particular be produced by means of exposure of a substrate, that is to say for example photolithographically or holographically. In this context, the optical grating can then also be referred to as a holographic or holographic-optical grating. Two types of holographic-optical gratings are known: holographic surface gratings (surface holografic gratings, short: SHG) and holographic volume gratings (volume holografic gratings, short: VHG). In the case of a holographic surface grating, the grating structure can be generated by optically deforming a surface structure of the substrate. Due to the modified surface structure, incident light can be deflected, for example reflected. Examples of holographic surface gratings are so-called sawtooth or blaze gratings. In contrast to this, in the case of holographic volume gratings, the grating structure can be incorporated into the entire volume or part of the volume of the substrate. Holographic surface gratings and holographic volume gratings are generally frequency-selective. However, optical gratings are also known which can diffract polychromatic light. These are called multiplexed volume holographic gratings (MVHG for short) and can be produced, for example, by changing the periodicity of the grating structure of an optical grating or by arranging several holographic volume grids one behind the other.

A polymer, in particular a photopolymer, or a film, in particular a photosensitive film, for example made of plastic or organic materials, is particularly suitable as the material for said substrate for incorporating an optical grating. To use such substrates for the flexible camera device, it should also be ensured that the material, in particular in substrate form, has flexible and light-wave-guiding properties. Substrates that have a deflection structure for diffracting light, both for example in the form of an optical grating can also be referred to as holographic-optical elements (HOE).

In a further embodiment it is provided that the deflection structures are formed in one piece with the light guide medium. The at least two in-coupling and the at least two out-coupling deflection structures can thus, for example, be incorporated directly into a surface structure or a volume of the light-conducting medium. That is, the respective deflecting structure can be etched or lasered, for example, into a surface of the light guide medium. Thus, the light guide medium itself can be designed as an HOE.

An alternative embodiment to this provides that the deflection structures are formed in at least one separate element from the light guide medium. That is to say that the coupling-in deflection structures, the coupling-out deflection structures and the light-conducting medium can be formed in separate substrates or elements. For example, the coupling-in deflection structures can form a first element, the coupling-out deflection structures can form a second element, and the light-guiding medium can form a third element against which the first and second elements are in contact. Thus, the deflection structures can be embodied in at least one HOE be det. For example, the coupling-in and coupling-out deflection structures can be formed in different sections of a holographic film or plate. To fasten the film or plate to the light guide medium, the film or plate can be glued to the carrier medium. Alternatively, the holographic film can also be designed as an adhesive film and adhere directly to the surface of the light-conducting medium by means of molecular forces, that is to say without adhesive.

In a further embodiment it is provided that the coupling-in deflection structures are formed serially one after the other with respect to a direction of incidence of the light. In other words, the coupling structures can be stacked from one another, their surfaces preferably completely overlapping. Alternatively, in a further version Guidance form provided that the coupling-in deflection structures are flat next to each other in the coupling-in area. In other words, the deflecting structures to be coupled in can be arranged in a plane next to one another, their surfaces preferably not overlapping.

In a further embodiment it is provided that each of the in-coupling deflecting structures has an area which is larger than a respective area of the at least two out-coupling deflection structures. The coupling-in area can thus also have a larger area than the coupling-out area. Preferably, an area of the respective in-coupling deflection structure can be larger by a factor of 2 than an area of the respective out-coupling deflection structure.

In order to deflect the light from the surroundings, the coupling-in area can have a bundling structure as the respective coupling-in deflection structure. By means of this bundling structure, the light incident from the environment can be bundled and deflected over the light guide medium to the Auskoppelbe rich. The respective optical grating of the respective deflecting structure to be coupled can be formed accordingly as a bundling grating. In other words, in a further embodiment, each of the coupling-in deflection structures is designed as an optical grating with a bundle grating structure. By means of the bundling grating structure, light beams of the light to be deflected, which from the surroundings hits the respective coupling-in deflection structure, are deflected to different degrees depending on a point of incidence. Thus, the respective in-coupling deflection structure bundles or focuses the light beams towards the respective out-coupling deflection structure. Preferably, the outcoupling area can furthermore have a diffusion structure as the respective outcoupling deflection structure. By means of this, the bundled light, in particular a beam of the light bundled by the respective coupling-in deflection structure, in particular a beam path of the light, when deflected at the diffusion structure, can be parallelized or straightened out of the carrier medium in order to be captured by the image capture device. The optical grating of the respective outcoupling deflection structure can thus correspond to accordingly be designed as a diffusion grating. In other words, it is provided in this embodiment that the at least two decoupling deflection structures are designed as an optical grating with a diverging grating structure. Due to the diverging grating structure, light beams of the coupled-in light that hits the respective outcoupling deflection structure are deflected to different degrees depending on a point of incidence. As a result, the respective outcoupling deflection structure parallelizes the light beams for acquisition by the image acquisition device. The light rays thus run parallel to one another for acquisition by the image acquisition device.

This results in a bundling of the light from the environment, so that a light intensity which strikes the image sensor of the image capturing device can be increased.

To implement a bundling grating or a diverging grating, for example, an inhomogeneous grating structure, in particular an aperiodic grating structure in sections, can be incorporated into the substrate described. Alternatively, several diffraction gratings with the same or different grating structures can be arranged or switched next to one another or one behind the other.

In a further embodiment it is provided that the image capturing device has a color image sensor for capturing the coupled-out light. In other words, the image capture device can have a color filter unit with which the captured light can be separated according to wavelengths or spectral ranges. The color filter device can function, for example, according to the Bayer principle or the Foveon principle. The color image sensor is thus designed in particular as a Bayer sensor or a Foveon X3 sensor.

The invention also relates to an alternative embodiment of the camera device for generating at least one image of an environment, comprising a light-conducting medium on which, opposite one another, on different ones Surfaces, a coupling area and an image capturing device are arranged. As described above, the coupling-in area has at least two coupling-in deflection structures, each of which is designed to couple light of a predetermined spectral range, which falls from a predetermined angle of incidence range from the surroundings onto the respective deflection structure, into the light-conducting medium, with the Einkop pelling deflection structures with respect to different spectral ranges and angles of incidence ranges are selective. The light-conducting medium is designed to transmit the coupled-in light from the coupling-in area to the imaging device. The image capturing device has at least two capturing areas, each of which is designed to capture the light of the predetermined spectral range that falls on the respective capturing area separately according to angle of incidence ranges from one of the coupling deflecting structures, and the image capturing device is designed to supply image data therefrom produce. This results in a particularly compact design of the camera device.

The light guide medium can thus be designed as a carrier unit or carrier medium, that is to say for carrying or holding the coupling area of the image acquisition device. In this case, the coupling area and the image capturing device are arranged opposite one another on the light-conducting medium, their respective surfaces preferably completely overlapping one another. The coupled-in light can thus shine through the light-conducting medium without being reflected internally and strike the image acquisition device for acquisition. The light-conducting medium can thus be designed to be penetrated by the coupled-in light and, in particular, to pass the coupled-in light on to the image capturing device. In this embodiment, the respective deflecting structure serves to deflect or deflect light from the respective angle of incidence range in a direction of incidence for the image detection device. For example, the light can be deflected from an angle of 45 degrees with respect to a normal to a surface of the light guide medium to a 0 degree angle (normal to the surface) for detection by the image detection device. As described above, light that has a different spectral range than the specified and hits the respective deflection structure from a different angle of incidence range than the previous one is deflected less or not and is thus preferably transmitted unhindered through the light-conducting medium. This preferably undeflected light can also be referred to as scattered light. In order to avoid the capture of scattered light in this embodiment of the camera device by the image capture device, the image capture device or its capture areas can also be designed to be angle-selective and wavelength-selective. To implement the wavelength selectivity, the image acquisition device can comprise a color filter unit, as is known, for example, from a Bayer sensor or another color image sensor. To realize the angle selectivity, the image capture device can comprise a diaphragm unit. This means that the detection areas can be separated from one another in the direction of incidence of light, for example, by a suitable arrangement of diaphragms. The arrangement of diaphragms can thus prevent the light that is intended for one of the detection areas from reaching another of the detection areas as scattered light. Other suitable measures for suppressing the scattered light can also be used.

The invention also relates to a motor vehicle with a camera device as described above. The light-conducting medium is designed as a window pane of the motor vehicle, that is to say, for example, as a windshield, a side window, or a rear window of the motor vehicle. The motor vehicle according to the invention is preferably configured as a motor vehicle, in particular as a passenger vehicle or truck, or as a passenger bus or motorcycle.

The invention also includes further developments of the motor vehicle according to the invention which have features as they have already been described in connection with the further developments of the camera device according to the invention. For this reason, the relevant further Formations of the motor vehicle according to the invention are not described again here.

The invention also includes the combinations of the features of the described embodiments.

Exemplary embodiments of the invention are described below. 1 shows a schematic representation of an advantageous embodiment of a camera device for capturing an enlarged field of view with only one image capturing device;

2 shows a schematic illustration of an alternative embodiment of the camera device; and

Fig. 3 is a schematic representation of a further alternative configuration from the camera device. The exemplary embodiments explained below are preferred embodiments of the invention. In the Ausführungsbeispie len, the described components of the embodiments each represent individual features of the invention to be considered independently of one another, which further develop the invention in each case also independently of one another. Therefore, the disclosure is also intended to include combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention already described. In the figures, the same reference symbols denote functionally identical elements.

1 shows a schematic illustration of an exemplary embodiment of a camera device 10 which is used to generate one or more images of a Environment with only one image capturing device 12 has an enlarged field of view FOV. The image acquisition device 12 is shown in FIG. 1 as an image sensor such as a CCD or a CMOS sensor. In order to capture the enlarged field of view FOV, the image capture device 12 is preceded by a deflection unit 11. The deflection unit 11 thus represents the imaging optics, ie the lens, of the camera device 10. In particular, the deflection unit 11 is a wide-angle or multi-view lens based on holographic-optical elements (HOE), that is, deflecting structures that are integrated into a suitable Substrate are incorporated, designed as bildge generating optics.

An FIOE is a well-known optical component that uses the physical effect of diffraction to direct light, e.g. similar to a lens or a mirror. However, an HOE has the advantage that, depending on a configuration of the deflection structure, it can deflect or deflect the light angle-selectively and / or wavelength-selectively. In addition, in contrast to a lens, an HOE can have a particularly large detection range or viewing angle of up to 170 degrees. This means that light that falls on the HOE at a steep or acute angle in relation to a surface of the HOE can also be deflected. Furthermore, the deflecting structure of an HOE can also be incorporated into a glass plate or film a few millimeters thick, in a particularly space-saving manner, with little effort. These properties of an HOE are now used in order to be able to capture the enlarged field of view FOV, preferably with a viewing angle greater than 60 degrees, in particular greater than 100 degrees, preferably between 0 degrees and 170 degrees, with only one image acquisition device 12, without imaging errors on the or the resulting images. For this purpose, the deflection unit 11 according to FIG. 1 now comprises several such deflection structures or HOEs. This divides the entire field of view FOV into several individual visual areas or angle of incidence areas T1, T2, T3. A partial area of the field of view FOV is thus recorded in each case by these angle of incidence areas T1, T2, T3. Preferably, the angle of incidence ranges can slightly overlap. Alterna- The angle of incidence ranges T1, T2, T3 as shown in FIG. 1 can, however, also directly adjoin one another.

In an advantageous embodiment of the camera device 10, not shown in FIG. 1, it can also be provided that the angle of incidence regions T1, T2, T3 capture separate regions in the vicinity. That is to say, the angle of incidence ranges T1, T2, T3 cannot abut or overlap one another.

A structure of the deflection unit 11 according to FIG. 1 is now briefly described below. The deflection unit 11 comprises a light guide medium 20 which is designed as a light guide. The light guide medium 20 is shown in Fig. 1 as a glass plate or glass pane. Alternatively, all other types of materials that have light-guiding properties, such as plastic, are also conceivable in order to provide the light-guiding medium 20. A coupling-in region 21 and a coupling-out region 22 are arranged on the light-conducting medium 20. Coupling area 21 and decoupling area 22 are arranged along a direction of longitudinal extent of the light guide medium 20 separately from one another on different sides or surfaces of the light guide medium 20.

For coupling in the light from the environment, the coupling area in FIG. 1 has three coupling-in deflection structures 23, 24, 25 or HOEs. These are planar, that is, in a plane next to one another in relation to a direction of incidence of the light from the environment and thus form the coupling-in area 21. Each of the coupling-in deflection structures 23, 24, 25 is designed to absorb light of a predetermined spectral range, which is composed of a nem of the respectively predetermined angle of incidence ranges T1, T2, T3 falls from the surroundings onto the respective deflecting structure 23, 24, 25, deflecting it in such a way that it is coupled into the light guide medium 20. Each of the deflecting structures 23, 24, 25 is formed with respect to a different union spectral range and angle of incidence range T1, T2, T3 selectively. For example, the first coupling-in deflection structure 23 for red light can be in a spectral range of approximately 470 nanometers to 780 nanometers and the incident angle range T1 can be selectively formed with a detection angle of 55 degrees. Correspondingly, the second deflection structure 24 can, for example, be selectively designed for green light in a spectral range of approximately 490 nanometers to 570 nanometers and the angle of incidence range T2 with a detection angle of 55 degrees. The third deflection structure

25, on the other hand, can be designed to be selective for blue light in a spectral range of approximately 430 nanometers to 490 nanometers and the angle of incidence range T3 with a detection angle of 55 degrees. Put together, this would result in a field of view FOV of 165 degrees for the camera device 10 according to FIG. 1.

After the light has been coupled into the light-conducting medium 20 by the coupling-in deflection structures 23, 24, 25, it is transmitted from the light-conducting medium to the coupling area 22 by means of internal reflection, in particular total reflection, by 20. Each of the outcoupling deflection structures 26, 27, 28 is assigned to one of the in-coupling deflection structures 23, 24, 25. In this context, “assigned” means that each of the outcoupling deflection structures 26, 27, 28 is selective with respect to the same spectral range as in each case one of the in-coupling deflection structures 23, 24, 25. For example, the first out-coupling deflection structure

26 to be assigned to the first coupling-in deflection structure 23. Only the light that was detected by the first coupling-in deflection structure 23 is therefore coupled out again from the light-conducting medium via the first deflecting structure to be coupled out. Analogously, for example, the second outcoupling deflection structure 27 is assigned to the second in-coupling deflection structure 24, so that only light that was detected by the second in-coupling deflection structure 24 is decoupled from the light guide medium 20 via the second out-coupling deflection structure 27. Correspondingly, the third outcoupling deflection structure 28 is assigned to the third in-coupling deflection structure 25, so that only light that was detected by the third in-coupling deflection structure 25 is decoupled from the light guide medium 20 via the third out-coupling deflection structure 28. In FIG. 1, the respective deflection structures are formed in separate elements from the light guide medium 20. Alternatively, however, the deflection structures could also be incorporated directly into a surface or a volume of the light guide medium 20, that is to say, for example, exposed or etched in.

Finally, the image capturing device 12 is arranged on the coupling-out region 22. Corresponding to the three decoupling deflection structures 26, 27, 28, the image capturing device 12 in FIG. 1 also has three different capturing areas 13, 14, 15 through which the decoupled light is captured. That is to say, each of the deflecting structures 26, 27, 28 to be coupled out is assigned to a respective detection area 13, 14, 15 of the image detection device 12. The respective detection area 13, 14, 15 thus only detects the decoupled light that was decoupled from the light guide medium 20 by the respectively assigned decoupling deflection structure 26, 27, 28. The image capturing device 12 can then generate image data from the captured light. A separate image data set is preferably generated for each detection area 13, 14, 15. Since the deflection structures 23, 24, 25, 26, 27, 28 separate the light from the environment according to wavelengths and angles of incidence areas T1, T2, T3, the image capturing device 12 can thus, according to the embodiment shown in FIG. 1, three areas according to the spectrum and angle of incidence T1, T2, T3 separate image data sets generated by. These image data sets can then either be used as separate single images of the surroundings or, as shown in FIG. 2, be calculated by a computing device 30 to form a common image U of the surroundings.

As shown in Fig. 1, the coupling-in deflection structures 23, 24, 25 and the outcoupling deflection structures 26, 27, 28 with the image capture device 12 are on different optical axes A and A '. This equalization of the optical axes A and A 'results from the fact that HOEs act transparently for all non-associated wavelengths and angle of incidence ranges. That is to say, light which has a different spectral range than the specified and which strikes the respective deflection structure from a different angle of incidence range T1, T2, T3 than the preceding one, does not is distracted. Without an offset of the optical axes A and A ', the image capturing device 12 would thus be superimposed with light or scattered light transmitted by the deflecting structures 23, 24, 25 that are coupled in. In order to avoid the capture of scattered light from the environment by the image capture device 12, it can advantageously be provided that a surface of the light guide medium 20, outside of the sections that include the coupling area 21 and the decoupling area 22, has a protective layer. This protective layer is designed to avoid the transmission of light from the environment through the light guide medium 20.

2 now shows an alternative embodiment of the deflection unit 11. Instead of two-dimensionally next to one another, the coupling-in deflection structures 23, 24, 25 are arranged here one after the other in series with respect to a direction of incidence of the light L1, L2, L3 from the surroundings. The surfaces of the coupling structures from 23, 24, 25 overlap in particular completely. The deflecting structures 23, 24, 25 to be coupled in can preferably be incorporated into a common substrate, for example by multiple exposure. Alternatively, the deflecting structures 23, 24, 25 to be coupled in can also be incorporated in a plurality of substrates or elements, which are then arranged in a sandwich construction, stacked on top of one another.

Using FIG. 2, the generation of an image U with an enlarged field of view FOV by means of the camera device 10 can now be described again. The light that falls onto the coupling region 21 from the environment in order to generate the image U is shown schematically in FIG. 2 as individual light components or light rays L1, L2, L3. A light beam L1 which has a wavelength in the red light range and falls, for example, within the angle of incidence range T1 on the coupling-in area 21, is coupled by the first coupling-in deflection structure 23 into the light guide medium 20 and transmitted there to the coupling-out area by means of internal reflection. The decoupling first deflection structure 26, which is assigned to the first coupling-in deflection structure 23, is also selective for light with a wavelength in the red light range, so that the light beam L1 overflows the first outcoupling deflection structure 26 is coupled from the light guide medium 20. The image acquisition device 12 is arranged on the decoupling area 22, the first detection area 13 thereof resting against the first deflection structure 26 to be decoupled. The decoupled light beam L1 can now be detected via the first detection area 13 and the image detection device 12 can generate the image data B1 from the light beam L1 detected by the first detection area 13. Similarly, for example, the image data B2 and B3 can each be generated by light beams L2 and L3, which have a wavelength in the green light range or in the blue light range and each strike the second or third coupling-in deflection structure 24, 24 in a corresponding angle of incidence range T2, T3. The individual image data B1, B2, B3 can then be combined by a computing device 30, which is also part of the camera device 10, to form the image U of the surroundings. The computing device 30 can then, for example, control a control signal S for a display device 40, such as a display in the multimedia interface of a motor vehicle, so that the image U, which shows the enlarged field of view FOV, is displayed to a user or driver of the motor vehicle.

Fig. 3 shows an alternative embodiment of the camera device 10. Here, the coupling area 21 and the image capturing device 12 are arranged opposite one another on different surfaces of the light guide medium 20, their surfaces completely overlapping. The light guide medium 20 thus serves as a carrier medium for the coupling area 21 and the image capturing device 12. Instead of forwarding by means of internal reflection, the light guide medium 20 in this embodiment is penetrated by the coupled light L1, L2, L3. Thus the light L1, L2,

L3, preferably without being deflected, can be transmitted or forwarded from the coupling area 21 to the image capturing device 12. In order to superimpose light L1, L2, L3 of different wavelengths or angle of incidence ranges T1, T2, T3 on the image capture device 12 in this embodiment, it is provided that each of the three capture areas 13, 14, 15 of the image capture device 12 according to the respectively assigned arranged coupling-in deflection structure 23, 24, 25 be designed to be wavelength-selective and angle-selective.

Overall, the examples show how a multi-view camera can be implemented with HOEs.

Claims

PATENT CLAIMS:

Camera device (10) for generating at least one image (U) of an environment, comprising a light guide medium (20) which is designed as a light guide and on which a coupling-in area (21) and a decoupling area (22) are arranged, and an image capturing device ( 12), which is arranged on the coupling-out region (22), the coupling-in region (21) having at least two coupling-in deflection structures (23, 24, 25), each of which is designed to produce light (L1, L2, L3) of a predetermined spectral range that falls onto the respective deflecting structure (23, 24, 25) from a given angle of incidence range (T1, T2, T3) from the surroundings, into the light guide medium (20), the deflecting structures (23, 24, 25) being coupled opposite different spectral ranges and angles of incidence ranges (T1, T2, T3) are selective, the light guide medium (20) is formed, the coupled light (L1, L2, L3) by means of internal reflection, from the coupling area (2 1) to be transmitted to the decoupling area (22), the decoupling area (22) has at least two decoupling deflection structures (26, 27, 28), each of which is formed by one of the decoupling deflection structures (23, 24, 25) ) coupled light (L1, L2, L3) of the predetermined spectral range that falls on the respective deflection structure (26, 27, 28) to be coupled out of the light guide medium (20), and the image acquisition device (12) at least two acquisition areas (13, 14 , 15), each of which is designed to detect the light (L1, L2, L3) decoupled from respectively one of the outcoupling deflection structures (26, 27, 28), and the image acquisition device (12) is designed to generate image data (B1 , B2, B3).

The camera device (10) according to claim 1, wherein the camera device (10) furthermore has a computing device (30) which is designed to generate separate images (U) from the generated image data (B1, B2, B3). provide.

3. Camera device (10) according to one of the preceding claims, wherein the camera device (10) further comprises a computing device (30) which is designed to use the generated image data (B1, B2,

B3) to provide a common image (U).

4. Camera device (10) according to one of the preceding claims, wherein at least one optical grating, in particular a holographic surface grating or a holographic volume grating, is provided as the respective deflection structure (23, 24, 25, 26, 27, 28).

5. Camera device (10) according to one of the preceding claims, wherein the deflection structures (23, 24, 25, 26, 27, 28) are formed in one piece with the light guide medium (20), or the deflection structures (23,

24, 25, 26, 27, 28) are formed in at least one separate element from the light guide medium (20).

6. Camera device (10) according to one of the preceding claims, wherein the coupling-in deflection structures (23, 24, 25) are formed serially one after the other with respect to a direction of incidence of the light (L1, L2, L3) or flat next to one another in the coupling-in area (21) are.

7. Camera device (10) according to one of the preceding claims, wherein each of the coupling-in deflection structures (23, 24, 25) has an area which is larger than an area associated with the coupling-out deflection structure (26, 27, 28).

8. Camera device (10) according to one of the preceding claims, wherein each of the coupling-in deflection structures (23, 24, 25) is designed as an optical grating with a bundling grating structure, which light rays of the light to be deflected (L1, L2, L3) from the In order to meet the respective coupling-in deflection structure (23, 24, 25), deflected to different degrees depending on a point of incidence, so that the coupling-in deflection structure (23, 24, 25) bundles the light beams (L1, L2, L3) to the respectively assigned outcoupling deflection structure (26, 27, 28) and each of the outcoupling deflection structures (26, 27, 28) as an optical grating is formed with a diffusion grating structure which deflects the light rays of the coupled-in light (L1, L2, L3) that strikes the respective outcoupling deflection structure (26, 27, 28) to different degrees depending on a point of incidence, so that the outcoupling deflection structure (26, 27 , 28) parallelizes the light beams for acquisition by the image acquisition device (12).

9. Camera device (10) according to one of the preceding claims, wherein the image capturing device (12) for capturing the out-coupled light (L1, L2, L3) has a color image sensor.

10. Camera device (10) for generating at least one image (U) of an environment, comprising a light guide medium (20) on which a coupling area (21) and an image capturing device (12) are arranged opposite on different surfaces, the coupling area (21 ) has at least two coupling-in deflection structures (23, 24, 25), each of which is designed to emit light (L1, L2, L3) of a predetermined spectral range from the surroundings from a predetermined angle of incidence range (T1, T2, T3) the respective deflecting structure (23, 24, 25) falls into the light guide medium (20), the deflecting structures (23, 24, 25) being selective with respect to different spectral ranges and angles of incidence (T1, T2, T3), the light guide medium ( 20) is designed to transmit the coupled light (L1, L2, L3) from the coupling area (21) to the image capturing device (12), and the image capturing device (12) we has at least two detection areas (13, 14, 15), each of which is designed to capture the light (L1, L2, L3) of the predetermined spectral range that is coupled in by one of the deflecting structures (23, 24, 25) that is coupled in, which is directed to the respective The respective detection area (13, 14, 15) falls, according to incidence angle areas (T1, T2, T3) to be detected separately and the image detection device (12) is designed to generate image data (B1, B2, B3) therefrom. 11. Motor vehicle with a camera device (10) according to one of the preceding claims, wherein the light guide medium (20) is designed as a window pane of the motor vehicle.