DEVICE FOR PROTECTING AN OPTICAL SENSOR

Abstract

The present invention relates to a device for protecting at least one optical sensor of a motor vehicle, the device being configured to be attached to the at least one optical sensor, the device comprising: a protective element comprising a transparent optical element rotatably mounted about an axis of rotation, the transparent optical element being configured to be arranged upstream of the at least one optical sensor. The device further comprises an optical sensor housing configured to receive the at least one optical sensor; and an actuator coupled to the protective element for rotating the transparent optical element, in order to allow dirt to be removed by a centrifugal effect.The device further comprises a signal processing unit configured to be coupled to the at least one optical sensor and configured to perform signal processing to remove at least one defect on an image captured by the at least one optical sensor.

Description

Title of the invention: DEVICE FOR PROTECTING AN OPTICAL SENSOR Technical field

[0001] The present invention relates to the field of driver assistance, and in particular to driving assistance systems installed in certain vehicles, the driving assistance system possibly comprising an optical sensor, for example a camera comprising a lens. More particularly, the invention relates to a device for protecting such an optical sensor. STATE OF THE ART

[0002] Currently, many motor vehicles are equipped with front, rear or side view cameras. In particular, such cameras are part of driver assistance systems such as parking assistance systems or lane departure detection systems. There are cameras that are installed inside the passenger compartment of a vehicle for parking assistance. These cameras are well protected from the weather and from soiling caused by organic or mineral contaminants. However, the viewing angle of such cameras installed inside the passenger compartment is not optimal, especially for parking assistance, since they do not provide a view of obstacles located near the rear of the vehicle, for example.

[0003] It is therefore preferable to install these driving assistance systems, and in particular their cameras, on the exterior of vehicles in various locations, depending on their intended use. In such a case, the driving assistance system, and in particular the camera of such a system, is greatly exposed to the weather and to projections of mineral or organic dirt which can reduce its effectiveness or even render it inoperative.

[0004] To counter the deposition of dirt on the driver assistance system, there is a known way of arranging a device for cleaning the optical component of the camera, generally a cleaning liquid sprayer located near the camera, making it possible to remove contaminants that have been deposited over time. However, the use of these sprayers increases the operating costs of such a driver assistance system, since they require the use of fairly large quantities of cleaning liquid. On the other hand, the optical component of the camera, generally consisting of a lens, is a relatively fragile device. It must therefore be protected against projections that could damage it. Consequently, such cameras are usually housed in enclosures protective covers including a protective window arranged opposite the lens. However, cleaning the lens, or the window in the casing that protects it, is of major importance for the correct operation of the camera. Summary of the invention

[0005] An object of the present invention is to provide an optical sensor protection device which is capable of identifying and removing defects on a lens and also capable of removing possible defects in at least one of the images captured by the optical sensor.

[0006] Another object of the present invention is to provide an optical sensor protection device which has a simple architecture, is less expensive and takes up less housing space compared to known protection devices.

[0007] Another object of the present invention is to provide an eccentric protection device for protecting the optical sensor, which is of lower cost than known protection devices and which uses a small optical window for image capture.

[0008] Another object of the present invention is to provide an eccentric protection device which allows dirt to be removed by a centrifugal effect and an aerodynamic effect.

[0009] To achieve these objectives, the present invention relates to a device for protecting at least one optical sensor of a motor vehicle, the device being configured to be attached to the at least one optical sensor, the device comprising: a protective element comprising a transparent optical element rotatably mounted about an axis of rotation, the transparent optical element being configured to be arranged upstream of the at least one optical sensor; an optical sensor housing configured to receive the at least one optical sensor; an actuator coupled to the protective element for rotating the transparent optical element, in order to allow dirt to be removed by a centrifugal effect;the device further comprising a signal processing unit configured to be coupled to the at least one optical sensor and configured to perform signal processing to remove at least one defect on an image captured by the at least one optical sensor.;

[0010] According to a characteristic of the present invention, the transparent optical element forms the protective element entirely.

[0011] According to a characteristic of the present invention, the axis of rotation of the transparent optical element coincides with an optical axis of the at least one optical sensor.

[0012] According to a characteristic of the present invention, the device further comprises at least one bearing configured to allow the protective element to be driven in a rotational movement relative to the at least one optical sensor.

[0013] According to a feature of the present invention, the at least one bearing element is positioned around the optical sensor housing.

[0014] According to a characteristic of the present invention, the transparent optical element is arranged partially inside the protective element and positioned in front of the at least one optical sensor.

[0015] According to a characteristic of the present invention, the axis of rotation of the transparent element diverges from the optical axis of the at least one optical sensor.

[0016] According to a characteristic of the present invention, the axis of rotation of the transparent element is parallel to the optical axis of the at least one optical sensor.

[0017] According to a characteristic of the present invention, the at least one bearing element is arranged around the axis of rotation of the transparent optical element, laterally relative to the optical sensor housing.

[0018] According to a feature of the present invention, the device further comprises a synchronization unit configured to synchronize a passage of the transparent optical element which is rotated with an image frequency of the at least one optical sensor.

[0019] According to a characteristic of the present invention, the transparent optical element is a flat element.

[0020] According to a characteristic of the present invention, the device further comprises a protective cover positioned in front of the transparent optical element.

[0021] According to a feature of the present invention, the protective cover is configured to provide an aerodynamic effect to the transparent optical element.

[0022] According to a characteristic of the present invention, the device comprises two or more optical sensors whose optical axes are angularly offset.

[0023] According to a feature of the present invention, the device further comprises an angular position detection unit operatively connected to the signal processing unit, and configured to determine an angular position of the transparent optical element to perform the signal processing.

[0024] According to a characteristic of the present invention, the device further comprises a spraying device arranged upstream of the protective element.

[0025] According to a feature of the present invention, the spraying device is arranged on an element of a vehicle, and the element being positioned closer to the device.

[0026] According to a feature of the present invention, the spraying device comprises a cover provided with a spray ramp configured to spray a washing fluid onto the protective element.

[0027] According to a feature of the present invention, the cover is configured to protect the transparent optical element when the protective element is in a fixed position.

[0028] According to a characteristic of the present invention, the present invention also relates to a driving assistance system for a motor vehicle, comprising: at least one optical sensor configured to capture images of a road scene; and a device making it possible to protect the at least one optical sensor such as that which has just been presented.

[0029] According to a characteristic of the present invention, the present invention also relates to a motor vehicle comprising the driving assistance system such as that which has just been presented.

[0030] Other advantages, attributes and details of the invention will become apparent from the following description of preferred embodiments of the invention and the drawings. BRIEF DESCRIPTION OF THE INVENTION

[0031] To complete the description and to enable a better understanding of the invention, a set of drawings is provided. Said drawings are an integral part of the description and illustrate an embodiment of the invention, which should not be considered as limiting the scope of the invention, but only as an example of the possible implementation of the invention. The drawings include the following features.

[0032] [Fig.l] schematically represents a motor vehicle comprising a driver assistance system according to an embodiment of the present invention.

[0033] [Fig.2] illustrates a longitudinal cross-sectional view of a device for protecting an optical sensor installed on a motor vehicle, according to a first embodiment of the present invention.

[0034] [Fig. 3] illustrates a longitudinal cross-sectional view of a device for protecting an optical sensor installed on a motor vehicle, according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] The description presented below in association with the accompanying drawings is intended to be a description of various embodiments of the disclosed subject matter and is not necessarily intended to represent the only embodiment(s). In some instances, the description includes specific details to provide an understanding of the disclosed subject matter. However, it will be apparent to those skilled in the art that embodiments may be implemented without such specific details.

[0036] Reference throughout the specification to "an embodiment" means that a particular attribute, structure, feature, operation, or function described in connection with an embodiment is included in at least one embodiment of the disclosed subject matter. Thus, any appearance of the phrase "in an embodiment" in the specification does not necessarily refer to the same embodiment. Furthermore, the particular attributes, structures, features, operations, or functions may be combined in any suitable manner in one or more embodiments. Furthermore, it is intended that embodiments of the disclosed subject matter may and do encompass modifications and variations of the disclosed embodiments.

[0037] Referring now to the drawings, like reference numerals designate like or corresponding parts throughout the various views. Hereinafter, illustrative embodiments of the present disclosure will be described in detail based on the drawings.

[0038] In the following description, “upstream” is defined by the direction of the light radiation, i.e. from the outside to the inside of the optical sensor.

[0039] In the following description, "soiling" means water droplets as well as traces of water, organic or mineral contaminants or a combination of these different elements.

[0040] [Fig.l] represents a motor vehicle 100 equipped with at least one driver assistance system 105 according to the invention. The driver assistance system 105 comprises a device 115 for protecting an optical sensor 110 for a motor vehicle, such as a camera having an optical component, a lens for example. The protective device 115 can be fixed, using any known technique, to any element 120 of the vehicle 100, such as to a bodywork element or to an external element such as a bumper, a rearview mirror or a license plate. For this purpose, mention may be made, in a non-exhaustive manner, of a fastening system, a screwing system or even an adhesive bonding system.

[0041] The optical sensor 110 is for example an optical image capture sensor 110 such as a camera. It may be a CCD (charge coupled device) sensor or a CMOS sensor comprising a matrix array of miniature photodiodes. According to another variant, it may be a LIDAR sensor, LIDAR meaning “light detection and ranging”.

[0042] [Fig.2] illustrates a longitudinal cross-sectional view of a device for protecting an optical sensor installed on a motor vehicle, according to a first embodiment of the present invention. The device 115 shown in [Fig.2] is configured to be attached to the at least one optical sensor 110. The device 115 comprises a protective element 130 comprising a transparent optical element 132 rotatably mounted about an axis of rotation. The transparent optical element 132 is configured to be arranged upstream of the at least one optical sensor 110. According to the first embodiment of the present invention, the transparent optical element 132 forms the protective element 130 entirely. Furthermore, the axis of rotation of the transparent optical element 132 coincides with an optical axis of the at least one optical sensor 110.

[0043] The device further comprises an optical sensor housing 134 configured to receive the at least one optical sensor 110, and an actuator 136 coupled to the protective element 130 to rotate the transparent optical element 132, to allow dirt to be removed by a centrifugal effect. For example, the actuator 136 comprises an electric motor, such as a brushless motor, to drive the transparent optical element 132. The actuator 136 comprises a stator 138 and a rotor 140, as shown in [Fig. 1]. The electric motor forming the actuator 136 is configured to rotate the optical element 132 at a speed of between 1000 and 50000 rpm, preferably between 5000 and 20000 rpm, and more preferably between 7000 and 15000 rpm.Such rotational speeds are sufficient to remove dirt deposited on the optical element 132 by a centrifugal effect, thereby maintaining the optical component of the optical sensor 110 in a clean state which is ideal for ensuring improved operation of the driver assistance system.

[0044] Further, the protection device 115 includes at least one bearing element 142, or rotatable support, configured to rotate the transparent optical element 9 relative to the optical sensor 110. According to the first embodiment of the present invention, the at least one bearing element 142 is positioned around the optical sensor housing. In one example, a single large diameter ball bearing is positioned around the optical sensor housing. Further, the diameter of the at least one ball bearing 142 is larger than the diameter of ball bearings used in known protection devices.

[0045] During operation, the actuator 136 drives the transparent optical element 132 in rotation relative to the optical sensor 110. This rotation is possible due to the presence of the at least one bearing element 142.

[0046] The device 115 further comprises an electronic control unit 150 configured to be coupled to the optical sensor 110, and is in particular configured to activate the actuator 136 in order to rotate the optical element 132. According to the embodiment described here, the actuator 136 is activated by the electronic control unit 150 such that the optical element 132 is constantly rotated during operation of the vehicle.

[0047] The electronic control unit 150 comprises a signal processing unit 152, an angular position detection unit 154. The angular position detection unit 154 is operatively connected to the signal processing unit 152, and configured to determine an angular position of the transparent optical element 132 to perform signal processing. For example, the angular position of the optical element may be determined using one of: an angular sensor, phase current detection, a grating of the optical element, etc. Further, the signal processing unit 152 is configured to be coupled to the at least one optical sensor 110 and configured to perform signal processing to remove defects on the lens 131 and also removes at least one defect on an image captured by the at least one optical sensor 110.For example, image frames of the same object may be captured and analyzed by the signal processing unit. If there is any defect, the defect may be located at different parts of the image frames. By analyzing the images, a position of the defect may be identified. Finally, the defect in the images may be removed using techniques known to those skilled in the art. Further, the signal analysis may be synchronized with the rotation of the lens 131 to detect and remove defects on the lens 131. Thus, the lifetime of the lens 131 may be increased and the quality of the images captured by the optical sensor 110 may also be improved.

[0048] [Fig. 3] illustrates a longitudinal cross-sectional view of a device for protecting an optical sensor installed on a motor vehicle, according to a second embodiment of the present invention. The protection device 215 according to this second embodiment is an eccentric device unlike the protection device 115 in the first embodiment. According to this second embodiment of the present invention, the protection device 215 comprises: a protective element 230 comprising a transparent optical element 232 mounted for rotation about an axis of rotation, the transparent optical element 232 being configured to be arranged upstream of the at least one optical sensor 210. An optical sensor housing configured to receive the at least one optical sensor.Further, the protective device 215 comprises an actuator 236 coupled to the protective element 230 for rotating the transparent optical element 232, to allow dirt to be removed by a centrifugal effect. The device 215 further comprises an electronic control unit 250 configured to be coupled to the optical sensor 210, and is particularly configured to activate the actuator 236 to rotate the optical element.

[0049] According to this embodiment, the transparent optical element 234 is arranged partially inside the protective element 232 and positioned in front of the at least one optical sensor 210. Thus, in this embodiment, only a part of the protective element is used as a transparent optical element, and the image capture is synchronized with the passage of the window in front of the optical sensor 210. In one aspect, the electronic control unit 250 comprises a synchronization unit 252 configured to synchronize a passage of the transparent optical element 234 which is rotated with a frame rate of the at least one optical sensor 210.

[0050] According to this embodiment, the rotation axis 220b of the transparent optical element 234 diverges from the optical axis 220a of the at least one optical sensor 210. In one example, the rotation axis 220b of the transparent element is parallel to the optical axis 220a of the at least one optical sensor 210.

[0051] Thus, the protection device 215 according to this embodiment is an eccentric device and the device is synchronized with the rotation. In other words, when the transparent optical element 234 passes through the front of the optical sensor 210, the electronic control unit 250 produces a signal to the optical sensor 210 to capture the images.

[0052] According to this second embodiment, the transparent optical element is a flat element.

[0053] Furthermore, as can be seen in [Fig.3], the device further comprises a protective cover 260 positioned in front of the transparent optical element 234. The protective cover 260 is configured to impart an aerodynamic effect to the transparent optical element 234 to deflect rain, mud, etc. so as to prevent them from striking the transparent optical element 234.

[0054] According to a variant of the second embodiment, the device 215 may comprise two or more than two optical sensors 210 whose optical axes are angularly offset.

[0055] Furthermore, as can be seen in [Fig. 3], the device further comprises a spraying device 265 arranged upstream of the protective element 232. For example, the spraying device 265 is arranged on an element of a vehicle, and the element being positioned closer to the device 215. The spraying device comprises a cover having a spray bar configured to spray a washing fluid onto the protective element 232. The cover is configured to protect the transparent optical element 234 when the protective element 232 is in a fixed position.

[0056] Advantageously, by having a small optical window, i.e. the transparent optical element, the protection device 215 can be produced at a lower cost compared to known protection devices.

[0057] According to another embodiment of the present invention, the present invention also relates to a driving assistance system for a vehicle automobile, comprising: at least one optical sensor configured to capture images of a road scene; and a device for protecting the at least one optical sensor such as that which has just been presented.

[0058] According to another embodiment of the present invention, the present invention also relates to a motor vehicle comprising the driving assistance system such as that which has just been presented.

[0059] Those skilled in the art will realize that the present invention is in no way limited to the preferred embodiments described above. On the contrary, numerous modifications and variations are possible within the scope of the appended claims. In addition, those skilled in the art will readily realize that the various embodiments described herein may be freely combined to obtain new combinations.

[0060] Furthermore, variations of the disclosed embodiments may be understood and made by those skilled in the art when practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. List of reference signs

[0061] 100 Motor vehicle

[0062] 105 Driver assistance system

[0063] 110 Optical sensor

[0064] 115 Protective device

[0065] 120 Vehicle element

[0066] 131 Optical sensor lens

[0067] 130 Protective element

[0068] 132 Transparent optical element

[0069] 134 Optical sensor housing

[0070] 136 Actuator

[0071] 138 Stator

[0072] 140 Rotor

[0073] 142 Landing

[0074] 150 Electronic control unit

[0075] 152 Signal processing unit

[0076] 154 Angular position detection unit

[0077] 215 Protective device

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] 210 Optical sensor 232 Protective element 234 Transparent optical element 236 Actuator 240 Bearing 220a Rotation axis of the transparent optical element 220b Optical axis 250 Electronic control unit 252 Synchronization unit 260 Protective cover 270 Spraying device

Claims

Claims

1. A device for protecting at least one optical sensor of a motor vehicle, the device being configured to be attached to the at least one optical sensor, the device comprising: • a protective element comprising a transparent optical element rotatably mounted about an axis of rotation, the transparent optical element being configured to be arranged upstream of the at least one optical sensor; • an optical sensor housing configured to receive the at least one optical sensor; • an actuator coupled to the protective element for rotating the transparent optical element, in order to allow dirt to be removed by a centrifugal effect; • the device further comprising a signal processing unit configured to be coupled to the at least one optical sensor and configured to perform signal processing to remove at least one defect on an image captured by the at least one optical sensor.

2. A device as claimed in claim 1, the transparent optical element forming the protective element entirely.

3. A device as claimed in any preceding claim, the axis of rotation of the transparent element coinciding with an optical axis of the at least one optical sensor.

4. A device as claimed in any preceding claim, the device further comprising at least one bearing configured to allow the protective element to be rotated relative to the at least one optical sensor.

5. A device as claimed in claim 1, the transparent optical element being arranged partially inside the protective element and positioned in front of the at least one optical sensor.

6. A device as claimed in claim 5, the device further comprising a synchronization unit configured to synchronize a passage of the transparent optical element being rotated with a frame rate of the at least one optical sensor.

7. A device as claimed in claim 5, the device further comprising a protective cover positioned in front of the transparent optical element.

8. A device as claimed in any preceding claim, the device further comprising an angular position detection unit operatively connected to the signal processing unit, and configured to determine an angular position of the transparent optical element to perform the signal processing.

9. A device as claimed in any preceding claim, the device further comprising a spraying device arranged upstream of the protective element.

10. Driving assistance system for a motor vehicle, comprising: • at least one optical sensor configured to capture images of a road scene; and • a device for protecting the at least one optical sensor as claimed in the preceding claims 1 to 9.

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