Receiver for an optical transmission system, optical transmission system and method for operating an optical transmission system

Abstract

The invention relates to a receiver (12) for an optical transmission system (10), comprising a camera (6) with an image sensor (4), wherein the light-sensitive surface of the image sensor (4) comprises a plurality of rows of light-sensitive elements, wherein the image sensor (4) is designed such that the light-sensitive surface of the image sensor (4) is scanned row by row or column by column, an attachment element (3) which is arranged such that light incident on the light-sensitive surface of the image sensor (4) first passes through the attachment element (3). Here, the attachment element (3) comprises a plurality of strip-shaped shaped regions (40) and a plurality of strip-shaped planar regions (32). The shaped regions (40) and the planar regions (32) are arranged alternately in a transverse direction (Q). The shaped regions (40) have a constant cross section in a preferential direction (V) which extends perpendicularly to the transverse direction (Q). The invention also relates to an optical transmission system (10) comprising a receiver (12) and a transmitter (14) according to the invention and to a method for operating an optical transmission system (10) according to the invention.

Description

Technical Field

[0001] This invention relates to a receiver for an optical transmission system, the receiver comprising: a camera having an image sensor, wherein the photosensitive surface of the image sensor includes multiple rows of photosensitive elements, and wherein the image sensor is designed such that the photosensitive surface of the image sensor is scanned row by row or column by column; and attachment elements arranged such that light incident on the photosensitive surface of the image sensor passes through the attachment elements beforehand. The invention also relates to an optical transmission system comprising a receiver and a transmitter according to the invention. Furthermore, the invention relates to a method for operating an optical transmission system according to the invention. Background Technology

[0002] From the paper "Using a CMOS Camera Sensor for Visible Light Communication" by Danakis et al., 978-1-4673-4941-3, IEEE has identified a system and method for transmitting data over visible light. In this method, a smartphone camera is used as a receiver for visible light. The camera includes a CMOS image sensor whose photosensitive surface is scanned line by line. A light source in the form of an LED that emits modulated light is used as the transmitter. A data transmission rate greater than the camera's image frequency is achieved by utilizing the rolling shutter effect of the CMOS image sensor.

[0003] A system and method for transmitting data via visible light are also known from DE 10 2018 006 988 B3. The system comprises: a receiver with an image sensor whose photosensitive surface is scanned line by line; and a transmitter with a controllable illumination device that emits modulated light. Here, the receiver has a lens film or cylindrical lens array arranged between the lens of the receiver and the transmitter. The image projected onto the photosensitive surface of the image sensor is thus blurred and imaged. An increased data transmission rate is achieved by utilizing the rolling shutter effect of the image sensor.

[0004] An optical system having an optical antenna device for illuminating an object is known from document DE 11 2006 000 484 T5. A second optical antenna element acquires a portion of the light reflected from the object. Here, the optical antenna device can selectively illuminate a spatial location, and the receiving optical antenna device can selectively receive the light. Summary of the Invention

[0005] The object of this invention is to improve a receiver for an optical transmission system, a corresponding system, and a method for operating the system.

[0006] The objective is achieved by a receiver for an optical transmission system having the features described in claim 1. Advantageous designs and improvements are the subject of the dependent claims. The objective is also achieved by an optical transmission system having the features described in claim 10. Advantageous designs and improvements are the subject of the dependent claims. The objective is also achieved by a method for operating an optical transmission system having the features described in claim 12. Advantageous designs and improvements are the subject of the dependent claims.

[0007] The receiver for an optical transmission system according to the invention includes a camera having an image sensor. Here, the photosensitive surface of the image sensor includes multiple rows of photosensitive elements. The image sensor is designed such that its photosensitive surface can be scanned row by row or column by column. The receiver also includes attachment elements. The attachment elements are arranged such that light incident on the photosensitive surface of the image sensor passes through the attachment elements beforehand.

[0008] The attachment element comprises multiple strip-shaped forming regions and multiple strip-shaped planar regions. Here, the forming regions and planar regions are arranged alternately in the transverse direction. The forming regions have a constant cross-section in a preferred direction that extends perpendicular to the transverse direction.

[0009] Light passing through the forming area of ​​the attachment element is strongly refracted and a first image is generated on the photosensitive surface of the image sensor. Therefore, the first image generated on the camera's image sensor is a blurred image. Specifically, the beam of light from a point source is imaged here in the form of light bars. When modulated light arrives, the aforementioned light bars are bright and dark in chronological order according to the modulation. Due to the row-by-row or column-by-column scanning of the photosensitive surface of the image sensor, the light bars can thus have bright and dark areas according to the modulation. Data streams can be detected from the bright and dark areas of the aforementioned light bars, and the light source emits modulated light according to the data stream.

[0010] Light passing through the planar region of the attachment element travels through the attachment element at least in a straight line and produces a second image on the photosensitive surface of the image sensor. Therefore, the second image produced on the camera's image sensor is a clear optical image.

[0011] Therefore, the receiver according to the invention can detect a data stream from a first image, which has a data transmission rate greater than the image frequency of the camera. A clear optical image can be detected from a second image. Thus, the receiver according to the invention is advantageously suited for rapid data transmission and also for simultaneously capturing clear optical images. Here, the attachment elements can be manufactured relatively simply and inexpensively.

[0012] According to a preferred embodiment of the invention, the attachment element is constructed in the form of a thin film or a plate. Here, the planar region has a constant material thickness. The thin film or plate is transparent.

[0013] According to an advantageous improvement of the invention, the forming region has a recess and therefore a smaller material thickness than the planar region. Thus, the forming region is concave. This results in the refraction of the incident light beam not being uniform throughout, but rather depending on the incident position. Here, the attachment element can be manufactured particularly simply and inexpensively by, for example, continuously milling the recess from a film or plate along a preferred direction.

[0014] According to another advantageous improvement of the invention, the forming region has a raised portion and therefore a greater material thickness than the planar region. Thus, the forming region is designed to be convex. This results in the refraction of the incident light beam not being uniform throughout, but rather depending on the incident position.

[0015] According to another advantageous improvement of the invention, the attachment element comprises: a molded region having a recess and thus having a material thickness smaller than that of a planar region; and a molded region having a raised portion and thus having a material thickness larger than that of a planar region.

[0016] According to an advantageous design of the invention, the molding area has a cross-section that is at least approximately semi-circular.

[0017] According to a preferred embodiment of the invention, the lateral extension dimension of one planar region is greater than the lateral extension dimension of one molding region. Specifically, the lateral extension dimension of each planar region is greater than the lateral extension dimension of each molding region.

[0018] Particularly preferably, the lateral extension dimension of one of the planar regions is at least twice the lateral extension dimension of one of the molding regions. Furthermore, particularly preferably, the lateral extension dimension of one of the planar regions is at most ten times the lateral extension dimension of one of the molding regions. Specifically, the lateral extension dimension of each planar region is at least twice the lateral extension dimension of each molding region. Furthermore, particularly preferably, the lateral extension dimension of each planar region is at most ten times the lateral extension dimension of each molding region.

[0019] According to an advantageous improvement of the invention, the receiver further includes a receiving unit. The receiving unit has a first receiving element and a second receiving element movable relative to the first receiving element. Here, the camera is received in the first receiving element, and the attachment element is received in the second receiving element. The attachment element can therefore move, for example, swing or move relative to the camera.

[0020] The optical transmission system according to the invention includes a receiver according to the invention and a transmitter having at least one controllable light source. The at least one light source of the transmitter emits modulated light according to a preset data stream.

[0021] According to an advantageous design of the invention, the attachment element of the receiver is arranged between at least one controllable light source of the transmitter and the camera of the receiver. This ensures that light incident on the photosensitive surface of the image sensor of the camera passes through the attachment element beforehand.

[0022] In the method according to the invention for operating the optical transmission system according to the invention, the photosensitive surface of the image sensor is scanned row by row or column by column. Here, a first image projected onto the photosensitive surface through the shaped region of the attachment element and a second image projected onto the photosensitive surface through the planar region of the attachment element are processed separately.

[0023] According to an advantageous design of the invention, a data stream is detected from a first image, according to which at least one controllable light source of the transmitter emits modulated light. Advantageously, the data transmission rate of the data stream is greater than the image frequency of the receiver's camera.

[0024] According to an advantageous embodiment of the invention, an optical image is detected from a second image. Here, the second image is advantageously a clear optical image.

[0025] Therefore, using the method according to the invention, different information can be simultaneously transmitted from the transmitter to the receiver using a first image and a second image, and received by the receiver. For example, coordinates can be encoded in the data stream. Then, localization can be performed by evaluating the data stream detected from the first image. For example, a QR code can be scanned by evaluating the second image.

[0026] This invention is not limited to the combination of features in the claims. For those skilled in the art, particularly for purposes proposed and / or by comparison with the prior art, other reasonable combinations of features in the claims and / or individual claims and / or the specification and / or the drawings are possible. Attached Figure Description

[0027] The invention will now be described in detail with reference to the accompanying drawings. The invention is not limited to the embodiments shown in the drawings. The drawings are merely schematic illustrations of the subject matter of the invention. The drawings show:

[0028] Figure 1 A schematic diagram of an optical transmission system is shown.

[0029] Figure 2 A top view of the attachment element is shown.

[0030] Figure 3 A cross-sectional view of the attachment element is shown, and

[0031] Figure 4 The overall image projected by the attached element is shown. Detailed Implementation

[0032] Figure 1 A schematic diagram of an optical transmission system 10 is shown. The optical transmission system 10 includes a transmitter 14 having a controllable light source 1. The light source 1 is, for example, an LED, a dome light, or a vehicle headlight. The optical transmission system 10 also includes a receiver 12.

[0033] Receiver 12 includes camera 6. Camera 6 has image sensor 4. Image sensor 4 has a photosensitive surface including multiple rows and columns of photosensitive elements. During operation of camera 6, the photosensitive surface of image sensor 4 is scanned row by row or column by column. The scanned rows are then arranged together to form a complete image. Camera 6 also includes optical elements in the form of optical lenses 8. Lens 8 is arranged in front of image sensor 4 such that light incident on the photosensitive surface of image sensor 4 passes through lens 8 beforehand. Camera 6 also includes signal electronics 5, which are specifically used for scanning the photosensitive surface of image sensor 4.

[0034] The receiver 12 also includes an attachment element 3. The attachment element 3 is arranged in front of the image sensor 4 such that light incident on the photosensitive surface of the image sensor 4 passes through the attachment element 3 beforehand. The attachment element 3 is constructed in the form of a relatively thin, transparent film. The attachment element 3 is arranged between the light source 1 of the transmitter 14 and the camera 6.

[0035] The camera 6 of receiver 12 is, for example, part of a commercially available mobile phone or smartphone. Receiver 12 may also include a housing unit. The housing unit is, for example, a box having a first housing element and a second housing element. Here, the second housing element can move relative to the first housing element, particularly by swinging. The mobile phone with camera 6 is housed in the first housing element, and the attachment element 3 is housed in the second housing element. The attachment element 3 can therefore move relative to camera 6, for example by swinging or moving. When data transmission through system 10 is not desired, the attachment element 3 can be removed from camera 6, and the camera can capture a complete optical image without the attachment element 3.

[0036] Figure 2 A top view of the attachment element 3 is shown. The attachment element 3 includes a plurality of strip-shaped molding regions 40 and a plurality of strip-shaped planar regions 32. The molding regions 40 and planar regions 32 are arranged alternately along the transverse direction Q and oriented parallel to the preferred direction V. Here, the preferred direction V extends perpendicularly to the transverse direction Q.

[0037] The strip-shaped forming region 40 of the attachment element 3 is configured such that light passing through the forming region 40 is refracted relatively strongly. Specifically, the light beam 60 from the point light source 1 is imaged in the form of a light strip 50 extending in the lateral direction Q. The light passing through the forming region 40 of the attachment element 3 produces a first image on the photosensitive surface of the image sensor 4. Due to the relatively strong refraction of light, the first image is blurred.

[0038] The planar region 32 of the attachment element 3 is configured such that light passing through the planar region 32 passes through the attachment element 3 at least in a near-straight line, i.e., without refraction or only slightly refracted. The light passing through the planar region 32 of the attachment element 3 produces a second image on the photosensitive surface of the image sensor 4. The second image is a clear optical image.

[0039] Figure 3 Show Figure 2 The cross-sectional view of the attachment element 3 shown is shown here. The cross-sectional view shown here extends through the attachment element 3 along the transverse direction Q and perpendicular to the preferred direction V. The molded region 40 and the planar region 32 are arranged alternately along the transverse direction Q as already mentioned.

[0040] The planar region 32 of the attachment element 3 has at least an approximately constant material thickness. The material thickness here refers to the length of the film extending in a direction perpendicular to the preferred direction V and perpendicular to the transverse direction Q. Therefore, the light beam 60 passes through the planar region 32 at least approximately in a straight line and is either not refracted or only slightly refracted.

[0041] The molding region 40 of the attachment element 3 has a recess 37 and is therefore concave. The molding region 40 thus has a smaller material thickness than the planar region 32. The molding region 40 here has a constant cross-section continuously along the preferred direction V. Currently, the molding region 40 has an approximately semi-circular cross-section. The light beam 60 incident on the molding region 40 is therefore refracted in different intensities along the transverse direction Q depending on the incident position.

[0042] It is also conceivable that the molding region 40 of the attachment element 3 has a raised portion and is therefore convex in shape. In this case, the molding region 40 has a larger material thickness than the planar region 32. The cross-section of the molding region 40 may also differ from a semi-circular shape.

[0043] The extension dimension of each planar region 32 along the lateral direction Y is greater than the extension dimension of each molding region 40 along the lateral direction Y. Currently, the extension dimension of each planar region 32 along the lateral direction Y is approximately 4 μm, and the extension dimension of each molding region 40 along the lateral direction Y is approximately 2 μm. Currently, the extension dimension of each planar region 32 along the lateral direction Y is approximately three times the extension dimension of each molding region 40 along the lateral direction Y. The extension dimensions of each planar region 32 and each molding region 40 along the lateral direction Y should be less than 1 mm.

[0044] Figure 4 Shown by in Figure 2 and Figure 3 The image shown is a projected overall image of the attachment element 3. The transmitter 14 that generates the overall image is currently a motor vehicle. The motor vehicle has two light sources 1, which are configured as headlights. The two light sources 1 are considered to be approximately point-shaped.

[0045] The overall image mentioned includes a first image generated by light passing through the molding area 40 of the attachment element 3. The overall image also includes a second image generated by light passing through the planar area 32 of the attachment element 3.

[0046] Light emitted by one of the light sources 1, reaching a portion of the forming area 40 of the attachment element 3, is refracted and imaged in the form of light stripes 50. The light stripes 50 generated by both light sources 1 extend here in the lateral direction Q.

[0047] Light emitted from the remainder of emitter 14 and reaching perpendicularly onto the planar region 32 of attachment element 3 passes through attachment element 3 at least in a generally straight line. This produces a second image. The second image is, in this case, a clear optical image.

[0048] The second image also shows relatively fine stripes with low brightness, extending in the preferred direction V. These stripes are produced by the portion of the shaped area 40 of the attachment element 3 where no light from the light source 1 reaches. However, the aforementioned stripes are relatively fine and therefore almost invisible in the overall image. Thus, the transmitter 14—currently a motor vehicle—is clearly identifiable in the overall image.

[0049] List of reference numerals in the attached diagram:

[0050] 1. Light source

[0051] 3. Attachment components

[0052] 4 Image Sensor

[0053] 5. Signal Electronic Devices

[0054] 6 cameras

[0055] 8 lenses

[0056] 10 System

[0057] 12 receivers

[0058] 14. Transmitter

[0059] 32 Planar region

[0060] 37. Depression

[0061] 40 Molding Area

[0062] 50 light bars

[0063] 60 beams

[0064] Q. Horizontal direction

[0065] V Priority Direction

Claims

1. A receiver (12) for an optical transmission system (10), the receiver comprising: A camera (6) having an image sensor (4), wherein the photosensitive surface of the image sensor (4) comprises multiple rows of photosensitive elements, wherein the image sensor (4) is designed such that the photosensitive surface of the image sensor (4) is scanned row by row or column by column; and An attachment element (3) is arranged such that light incident on the photosensitive surface of the image sensor (4) passes through the attachment element (3) beforehand. Its features are, The attachment element (3) includes multiple strip-shaped forming regions (40) and multiple strip-shaped planar regions (32), which are arranged alternately in the transverse direction (Q). The forming regions (40) have a constant cross-section in the preferred direction (V), which extends perpendicular to the transverse direction (Q).

2. The receiver (12) according to claim 1, characterized in that, The attachment element (3) is constructed in the form of a thin film or a plate, wherein the planar region (32) has a constant material thickness.

3. The receiver (12) according to claim 2, characterized in that, The molding area (40) has a recess (37) and a smaller material thickness than the planar area (32).

4. The receiver (12) according to claim 2, characterized in that, The forming area (40) has a raised portion and a greater material thickness than the planar area (32).

5. The receiver (12) according to claim 2, characterized in that, The attachment element (3) includes: a molded region (40) having a recess (37) and thus having a material thickness smaller than that of the planar region (32); and a molded region (40) having a raised portion and thus having a material thickness larger than that of the planar region (32).

6. The receiver (12) according to any one of the preceding claims, characterized in that, The forming area (40) has a cross-section that is at least approximately semi-circular.

7. The receiver (12) according to any one of the preceding claims, characterized in that, The extension dimension of one of the planar regions (32) in the lateral direction (Y) is greater than the extension dimension of one of the forming regions (40) in the lateral direction (Y).

8. The receiver (12) according to any one of the preceding claims, characterized in that, The extension dimension of one of the planar regions (32) in the lateral direction (Y) is at least twice the extension dimension of one of the forming regions (40) in the lateral direction (Y), and / or the extension dimension of one of the planar regions (32) in the lateral direction (Y) is at most ten times the extension dimension of one of the forming regions (40) in the lateral direction (Y).

9. The receiver (12) according to any one of the preceding claims, further comprising a receiving unit, characterized in that, The housing unit has a first housing element and a second housing element that can move relative to the first housing element, wherein the camera (6) is housed in the first housing element and the attachment element (3) is housed in the second housing element.

10. An optical transmission system (10) comprising a receiver (12) according to any one of the preceding claims and a transmitter (14) having at least one controllable light source (1), the at least one controllable light source emitting modulated light according to a preset data stream.

11. The system (10) according to claim 10, characterized in that, The attachment element (3) is arranged between the at least one controllable light source (1) and the camera (6).

12. A method for operating an optical transmission system (10) according to any one of claims 10 to 11, characterized in that, The photosensitive surface of the image sensor (4) is scanned row by row or column by column, wherein a first image projected onto the photosensitive surface through the shaped area (40) of the attachment element (3) is processed separately from a second image projected onto the photosensitive surface through the planar area (32) of the attachment element (3).

13. The method according to claim 12, characterized in that, From the first image detection data stream, based on the data stream, at least one controllable light source (1) of the transmitter (14) emits modulated light.

14. The method according to any one of claims 12 to 13, characterized in that, Detect optical images from a second image.

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