Method for cleaning a protection device of a driver assistance system of a motor vehicle and associated driver assistance system

Abstract

The invention relates to a method for cleaning a protection device (3) for a driving assistance system (1), the protection device comprising an optical sensor (13) with an optical instrument (14), the protection device (3) having an optical element (9) arranged upstream of the optical instrument (14) and having an inner surface (9a) and an outer surface (9b) and being movably mounted about a rotation axis (Al), the method comprising the steps of processing a series of images acquired by the optical sensor (13) as the optical element (9) rotates in order to detect a substantially circular or semi-circular shape centered on the rotation axis (Al) of the optical element (9) and generated by dirt deposited on the outer surface (9b), and if the shape is detected, triggering at least one action for cleaning the outer surface (9b) of the optical element (9). The invention also relates to an associated driving assistance system (1).

Description

Technical Field

[0001] This invention relates to the field of driver assistance, and more particularly to the cleaning of driver assistance systems installed in some vehicles. Driver assistance systems may include optical sensors, such as cameras including objective lenses, designed to acquire at least one image, and particularly include at least one lens, said optical sensor being at least partially housed in a protective device. Furthermore, this invention also relates to a method for cleaning such a protective device. Background Technology

[0002] Currently, a large number of motor vehicles are equipped with forward-facing, rear-facing, or even side-facing cameras. In particular, these cameras form part of driver assistance systems, such as parking assist systems or even lane departure warning systems.

[0003] Cameras are known to be installed inside the passenger compartment of a vehicle, near the rear windshield / window, and pointing rearwards through the rear windshield. These cameras are well protected from external weather events and dirt caused by organic or inorganic contaminants. The field of view of such cameras can be cleaned with a squeegee blade, which wipes the rear window of the vehicle to remove dirt. However, the field of view of such cameras installed inside the passenger compartment is not optimal, especially for parking assist systems, as they do not allow visibility of obstacles located near the rear of the vehicle.

[0004] Therefore, depending on the intended use, cameras for driver assistance systems are preferably mounted in different locations on the exterior of the vehicle, such as on the rear or front bumper, or even on the rear or front license plate. In this case, the camera is thus highly exposed to splashes of organic or inorganic contaminants, which may deposit on its optics, reducing its effectiveness or even rendering it inoperable. In particular, contaminant splashing has been observed in rainy weather, which significantly affects the operability of driver assistance systems including such cameras. Therefore, the surfaces of the camera's optics must be cleaned to ensure they remain in good working order. To this end, one or more operations for cleaning the optical sensors can be triggered, such as spraying a cleaning fluid, to remove contaminants present in the field of view of the optical sensors.

[0005] To limit the operation of cleaning such optical sensors, driver assistance systems are known from the prior art, which have cameras including image processing devices capable of detecting the presence of dirt in the field of view of the optical sensor so as to trigger possible cleaning actions when dirt is detected.

[0006] However, in the case of such driver assistance systems, dirt can only be detected when the vehicle is moving. In practice, to determine whether the shape detected by the optical sensor corresponds to dirt or a shadow, the vehicle must be moving, allowing the optical sensor to capture multiple images corresponding to various road scenes. The captured images are then compared to verify whether the detected shape corresponds to a shadow or dirt. If the shape is persistent and stationary across the captured road scenes, this indicates the presence of dirt. Otherwise, it indicates it is simply a shadow. Therefore, the method for detecting dirt implemented by such driver assistance systems is lengthy and complex. According to another solution, a device for protecting the optical sensor is known, comprising an optical element forming a protective shield, designed to be positioned upstream of the camera optics.

[0007] According to one existing technology solution, the optical element corresponds to a protective glass with a vibrating device configured to vibrate the glass to remove any dirt. However, it has been found that despite the vibration of the protective glass, the effectiveness of such a device against stubborn and crusted dirt may be limited. Furthermore, this device lacks a means to detect the presence of dirt before the user commands the protective glass to vibrate to allow it to be cleaned.

[0008] According to another solution in the prior art, the optical element is designed to be rotated by an actuator in order to remove any contaminants by means of the centrifugal force associated with the rotation of the optical element. Thus, the optical sensor is protected by the optical element, and the optical element is cleaned by its rotation.

[0009] However, some contaminants may accumulate at points on the optics where the centrifugal force is too weak to remove them. Furthermore, stubborn dirt can accumulate on the optics when they have been stationary for extended periods, making it difficult to remove through centrifugal force. This driver assistance system does not offer any solution for automatically detecting the presence of such contaminants. Summary of the Invention

[0010] The object of the present invention is to overcome at least in part the above-mentioned disadvantages of the prior art by proposing a method for cleaning protective devices, which allows for efficient and automatic cleaning of optical elements arranged upstream of the optical devices of optical sensors forming a driver assistance system, and is easy to implement without requiring the movement of the motor vehicle.

[0011] Another object of the present invention is to provide a driver assistance system having a device for detecting contaminants, particularly stubborn or crusted contaminants, deposited on a rotating optical element arranged upstream of the optical element of the driver assistance system's optical sensor.

[0012] Therefore, the object of the present invention is a method for a protective device for cleaning a driver assistance system of a motor vehicle, the driver assistance system including an optical sensor having optical elements, and the protective device having an optical element disposed upstream of the optical elements, the optical element having an inner surface facing the optical elements and an outer surface opposite to the inner surface, and being movably mounted about a rotation axis.

[0013] The method includes the following steps:

[0014] As the optical element rotates, a series of images acquired by the optical sensor are processed to detect, on the acquired images, a roughly circular or semi-circular shape centered on the rotation axis of the optical element and formed by contaminants deposited on the outer surface of the optical element; and

[0015] If the shape is detected, at least one action is triggered to clean the outer surface of the optical element.

[0016] Detecting a circular or semi-circular shape centered on the rotation axis of the optical element allows for the detection of any contaminants. Images of roughly circular or semi-circular shapes, acquired by the optical sensor both when the vehicle is moving and when it is stationary, are obtained. In practice, it is unlikely that an optical sensor will acquire an image with this shape unless there is any contaminant on the outer surface of the optical element of the protective device. It has been found that rotationally symmetrical objects whose centers coincide with the rotation axis of the optical element are rare in road scenes typically captured by optical sensors.

[0017] Furthermore, this detection of the shape that triggers at least one cleaning action allows the driver assistance system to exhibit good operability, which is achieved by removing the dirt once it is detected.

[0018] The cleaning method according to the present invention may also include one or more of the following features, individually or in combination.

[0019] The method includes a step in which an optical sensor acquires a series of images prior to a processing step, the acquisition step being performed whether the motor vehicle is moving or stationary.

[0020] The image processing device of the driver assistance system is used to perform a series of image processing steps.

[0021] The steps of processing a series of images include at least one of the following sequences: a sequence for detecting the brightness of each pixel in each image acquired by the optical sensor, a sequence for detecting at least one dark area on each pixel in each image acquired by the optical sensor, or a sequence for comparing a series of images acquired by the optical sensor with each other.

[0022] According to one aspect, when a motor vehicle starts, the optical elements are set to begin rotating.

[0023] On the other hand, once the optical sensor is triggered, the optical element is set to begin rotating.

[0024] This cleaning method is applied whether the vehicle is moving or stationary.

[0025] According to a particular embodiment, after a step that triggers at least one cleaning action, a series of image processing steps are repeated at least once.

[0026] According to the first embodiment, when the optical element is fixed, at least one cleaning action is performed.

[0027] According to the second embodiment, at least one cleaning action is performed when the optical element rotates.

[0028] According to a particular embodiment, the at least one cleaning action is selected from actions for modifying the rotational speed of the optical element, actions for spraying cleaning fluid (e.g., cleaning liquid or compressed air), actions for stopping the rotation of the optical element, and actions for passing a wiping component (e.g., a wiping blade) across the outer surface of the optical element, or even a combination of these actions.

[0029] Optionally, the cleaning method includes a drying step, during which the optical element is set to begin rotating.

[0030] The drying step is carried out within a dwell time of, for example, less than three seconds.

[0031] The present invention also relates to a driver assistance system for a motor vehicle, comprising an optical sensor and a protective device for the optical sensor, the optical sensor having optical elements and configured to acquire at least one image, the protective device comprising:

[0032] An optical element, disposed upstream of the optical device of an optical sensor and movably mounted about a rotation axis, the optical element having an inner surface facing the optical device and an outer surface opposite the inner surface; and

[0033] An actuator configured as a rotating optical element;

[0034] The driver assistance system includes:

[0035] - An image processing device configured to process a series of images acquired by an optical sensor as the optical element rotates, in order to detect a generally circular or semi-circular shape centered on the rotation axis of the optical element, resulting from contaminants deposited on the outer surface of the optical element; and

[0036] - At least one electronic control unit is configured to communicate with an image processing device and, when the shape is detected by the image processing device, trigger at least one action for cleaning the outer surface of the optical element.

[0037] Therefore, driver assistance systems allow the aforementioned cleaning methods to be implemented.

[0038] Driver assistance systems may also include one or more of the following features, individually or in combination.

[0039] The image processing device is configured to send at least one signal to at least one electronic control unit indicating the presence of the shape, so that when the shape is detected, at least one action for cleaning the outer surface of the optical element is triggered.

[0040] According to a first alternative embodiment, the optical sensor includes an image processing device.

[0041] According to a second alternative embodiment, the image processing device is integrated into the electronic control unit.

[0042] According to the first aspect, the image processing device is configured to implement a sequence for detecting the brightness of each pixel in each image acquired by the optical sensor, or a sequence for detecting at least one dark area on each pixel in each image acquired by the optical sensor, in order to detect the shape.

[0043] According to this first aspect, the image processing device is configured to implement an algorithm for performing one or more detection sequences.

[0044] According to the second aspect, the image processing device is configured to implement a sequence for comparing a series of images acquired by an optical sensor with each other in order to detect the shape.

[0045] According to the first embodiment, an electronic control unit configured to trigger at least one cleaning action is configured to control an actuator for rotating optical elements.

[0046] According to a second embodiment, the driver assistance system includes at least one first electronic control unit and an additional electronic control unit, the first electronic control unit being configured to control an actuator for rotating optical elements, and the additional electronic control unit being configured to trigger at least one cleaning action.

[0047] According to a particular embodiment, at least one electronic control unit configured to control the actuator is configured to command a change in the rotational speed of the optical element in order to perform at least one cleaning action.

[0048] According to another specific embodiment, the driver assistance system also includes at least one nozzle configured to spray cleaning fluid onto the outer surface of the optical element when at least one cleaning action is triggered.

[0049] The nozzle is controlled by at least one electronic control unit, which is configured to trigger at least one cleaning action.

[0050] According to one aspect, the nozzle is connected to the compressor so as to spray compressed air onto the outer surface of the optical element.

[0051] According to another aspect, the nozzle is connected to a cleaning liquid reservoir so as to spray the cleaning liquid onto the outer surface of the optical element.

[0052] According to another specific embodiment, the driver assistance system also includes at least one wiping component, such as a wiping blade, configured to clean the outer surface of the optical element in order to wipe the outer surface.

[0053] The wiping device is controlled by at least one electronic control unit.

[0054] According to one specific embodiment, the driver assistance system includes a first electronic control unit configured to control actuators and electronic control units for each wiper component for performing at least one cleaning action. Attached Figure Description

[0055] Further advantages and features of the invention will become more apparent from the following description, provided by way of non-limiting specification, and in conjunction with the accompanying drawings, in which:

[0056] Figure 1 This is a schematic perspective view of a driver assistance system;

[0057] Figure 2 This is a schematic perspective view of a driver assistance system according to a specific embodiment;

[0058] Figure 3 yes Figure 1 A schematic diagram of an exploded cross-section of a driver assistance system;

[0059] Figure 4 According to the first alternative embodiment Figure 1 A flowchart of the operation of a driver assistance system;

[0060] Figure 5 According to the second alternative embodiment Figure 1 A flowchart of the operation of a driver assistance system;

[0061] Figure 6 According to the third alternative embodiment Figure 1A flowchart of the operation of a driver assistance system;

[0062] Figure 7 It shows the cleaning Figure 1 A flowchart of a method for a protective device for a driver assistance system;

[0063] Figure 8A This is a schematic diagram of images acquired by the optical sensors of a driver assistance system, showing dirt on a protective device upstream of the optical sensors; and

[0064] Figure 8B yes Figure 8A The diagram of the image obtained shows that there is no dirt on the protective device. Detailed Implementation

[0065] In these figures, the same elements are labeled with the same reference numerals.

[0066] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference involves the same embodiment, or that a feature applies only to one embodiment. Simple features of various embodiments may also be combined or interchanged to provide other embodiments.

[0067] Throughout the following description, references are made to the first electronic control unit and the additional electronic control unit, as well as the first and second cleaning actions. The index is used only to distinguish and indicate similar but not identical elements. This index does not imply that one element takes precedence over another, and such naming is readily interchangeable without departing from the scope of this specification. The index also does not imply chronological order, for example, for evaluating the implementation of a method for cleaning the optical sensor protection device, or even for evaluating the arrangement of the various components constituting a driver assistance system.

[0068] refer to Figures 1 to 6 The present invention relates to a driver assistance system 1 for a motor vehicle.

[0069] In the following description, the term "front of a motor vehicle" corresponds to the face of the motor vehicle exposed to airflow during normal operation, particularly the face with headlights. In contrast, the term "rear of a motor vehicle" is understood to refer to the face of the motor vehicle opposite to the front.

[0070] Furthermore, "upstream" in the following description is defined as the direction of light rays, i.e., from the outside to the inside of the optical sensor 13 of the driver assistance system 1. Thus, the first element arranged upstream of the second element is positioned ahead of the second element in the direction of light propagation within the optical sensor 13. Similarly, "downstream" in the following description is also defined according to the direction of light propagation within the optical sensor 13. Therefore, the first element arranged downstream of the second element is positioned behind the second element in the direction of light propagation within the optical sensor 13.

[0071] Furthermore, “dirt” in the following description is understood to refer to water droplets or traces of water present on the optical element 9 upstream of the optical sensor 13, or even organic contaminants such as insects, or mineral contaminants such as mud, or even combinations of these various elements.

[0072] Furthermore, in the following description, “luminance” is understood to refer to the visually perceived value corresponding to the luminosity of a surface. More specifically, luminance corresponds to the power of visible light emitted per unit surface area and per unit solid angle in a given direction, passing through or at a point on the surface.

[0073] In the following description, "transparent" is understood to mean a light-transmitting material through which an object is clearly visible, particularly an object disposed on the exterior of a motor vehicle, and whose image is captured by optical sensor 13. Specifically, the transparent material described below can be colored or colorless.

[0074] refer to Figures 1 to 3 An embodiment of a driver assistance system 1 for a motor vehicle is shown. The driver assistance system 1 includes an optical sensor 13 and a protective device 3 for the optical sensor 13.

[0075] The optical sensor 13 may be, for example, an image capture optical sensor, such as a camera. For instance, it may be a CCD (charge-coupled device) sensor or a CMOS sensor comprising a matrix of miniature photodiodes. According to another alternative embodiment, it may be a sensor for remote laser sensing, known as a LIDAR (light detection and ranging) sensor. Thus, the optical sensor 13 is configured to acquire at least one image.

[0076] The optical sensor 13 includes an optical element 14 having an optical axis 15. The optical element 14 may be, for example, an objective lens. The objective lens may include at least one lens, and particularly, depending on the field of view and resolution of the optical sensor 13, may include multiple lenses, for example, between two and ten lenses, typically four or five lenses, or even ten lenses in the case of a fisheye 14. At least one of the lenses of the optical element 14 is convex (dome-shaped), for example, with the convex surface facing outwards from the optical sensor 13, for example, in the case of a "fisheye" lens.

[0077] In addition, a support 17 for the optical sensor 13 (such as...) can be provided. Figure 3 (As shown). The retainer 17 is arranged behind the optical sensor 13, on the side opposite to the optical device 14. According to reference... Figures 1 to 3 In the embodiment shown, the optical sensor 13 and the support 17 are intended to be fixedly mounted in the protective device 3.

[0078] The driver assistance system 1 can be installed at the front of the vehicle, for example, at the same level as the bumper. As a variation, the driver assistance system 1 can be installed at the rear of the vehicle, for example, at the same level as the bumper or license plate. According to yet another alternative embodiment, the driver assistance system can be installed on the side of the vehicle, for example, on a rearview mirror.

[0079] The driver assistance system 1, and more specifically the protective device 3, can be attached to any component of a motor vehicle using any technology known to those skilled in the art. Figure 1 and 2 In one embodiment, the driver assistance system 1 is installed in a body component 2, such as a bumper with an opening through which at least the optics 14 of the optical sensor 13 protrudes.

[0080] Reference Figures 1 to 3 The protection device 3 includes an optical element 9 movably mounted around a rotation axis A1 and an actuator 5, such as a motor, configured to rotate the optical element 9. The optical element 9 is arranged upstream of the optical device 14 of the optical sensor 13. Therefore, as referenced... Figure 1 and 2As shown, with the driver assistance system 1 installed on the motor vehicle, the optical element 9 also protrudes from the body element 2. More specifically, the optical element 9 has an inner surface 9a facing the optical device 14 and an outer surface 9b opposite to the inner surface 9a. Therefore, the optical element 9 is designed to protect the optical device 14 of the optical sensor 13 from any spray of dirt or solid debris that could damage the optical device 14. Thus, it is a protective element, or more specifically, a protective cover for the optical sensor 13, and it is this optical element 9 that is attacked from the outside, i.e., equivalently subjected to sprays of water, contaminants, stone chips, and deposits of contaminants or traces of water.

[0081] Furthermore, rotating the optical element 9 around the rotation axis A1 allows any contaminants to be removed from the outer surface 9b via centrifugal effect. According to Figure 3 In a particular embodiment, optical element 9 is separate from optical sensor 13. According to an alternative embodiment not shown herein, optical element 9 may be a component of optical device 14, particularly an external lens of optical device 14.

[0082] The optical element 9 is designed to cover at least the entire surface of the optical device 14. Therefore, the optical element 9 is arranged within the field of view of the optical sensor 13. For this purpose, the optical element 9 is transparent so as not to impair the operability of the optical sensor 13. The optical element 9 can be made of glass or a transparent plastic such as polycarbonate.

[0083] Furthermore, the outer surface 9b of the optical element 9 can have one or more of the following properties: hydrophobicity, infrared filtering, photocatalysis, superhydrophobicity, oleophobicity, hydrophilicity, superhydrophilicity, stone chip resistance, or even any other surface treatment for reducing dirt adhesion. In particular, by virtue of the hydrophobic properties of the outer surface 9b of the optical element 9, any water droplet flowing down the outer surface 9b of the optical element 9 will not leave a trace, because water will not adhere to the outer surface 9b. Therefore, this allows for limiting the presence of water traces on the optical element 9, which can impair the proper operation of the driver assistance system 1, particularly the quality of the images acquired by the optical sensor 13. Furthermore, according to the surface treatment of the outer surface 9b, the possibility of organic or inorganic contaminants adhering to the outer surface 9b can be limited, thereby also contributing to the proper operation of the driver assistance system 1. Furthermore, the optical element 9 has an optical axis 91 that coincides with the rotation axis A1 of the optical element 9. Furthermore, according to... Figures 1 to 3 In this embodiment, the optical axis 15 of the optical sensor 13 and the rotation axis A1 of the optical element 9 also coincide.

[0084] According to reference Figure 3In the illustrated embodiment, the protective device 3 may further include a housing 6 configured to at least partially house the optical sensor 13. According to this particular embodiment, the housing 6 and the optical element 9 form a single piece. According to another embodiment not shown herein, the housing 6 and the optical element 9 may be two separate parts joined together. The housing 6 is arranged to be rotated by an actuator 5, which causes the optical element 9 to rotate in order to remove any contaminants present on the outer surface 9b of the optical element 9 by centrifugal effect. Furthermore, the housing 6 may be a sealed housing made of any suitable material known to those skilled in the art. Additionally, the housing 6 may have anti-condensation devices, such as at least one through-hole 61 formed in the housing 6 by perforation, and the through-hole 61 preferably has one or more semi-permeable membranes (not shown). In this case, devices can be provided to compensate for any mass loss that may be caused by such perforation so as not to cause the rotation of the optical element 9 to become unbalanced.

[0085] The actuator 5 is configured to rotate the housing 6 at a speed range, for example, between 1,000 and 50,000 rpm, preferably between 5,000 and 20,000 rpm, and even more preferably between 7,000 and 15,000 rpm. This rotational speed allows most of the dirt that may have been deposited on the outer surface of the optical element 9 to be removed by centrifugal force.

[0086] To detect contaminants on the outer surface 9b of the optical element 9, particularly stubborn contaminants such as crusts or deposits caused by prolonged parking of the vehicle, where the contaminants are located in a position that makes them difficult to remove by centrifugal force, the driver assistance system 1 also includes an image processing device 7 and at least one electronic control unit 11, as shown in reference 1. Figures 4 to 6 As shown.

[0087] Image processing device 7 is configured to process a series of images acquired by optical sensor 13 as optical element 9 rotates. More specifically, image processing device 7 is configured to detect a generally circular or semi-circular shape 8 centered on the rotation axis A1 of optical element 9. Figure 8A(Illustrated schematically). Due to the rotation of optical element 9, if any dirt is present on the outer surface 9b of optical element 9, this will result in the circular or semi-circular shape 8. In other words, this approximately circular or semi-circular shape centered on the rotation axis A1 of optical element 9 is produced by dirt deposited on the outer surface 9b of optical element 9. In images acquired by optical sensor 13, it has been found that it is impossible to detect this shape in images acquired by optical sensor 13 when there is no dirt on the outer surface 9b of optical element 9. In fact, rotationally symmetric objects centered on the rotation axis A1 of optical element 9 are rare in road scenes acquired by optical sensor 13. Therefore, the detection of dirt in the field of view of optical sensor 13 is improved. Furthermore, images acquired by optical sensor 13 and analyzed by processing device 7 for detecting this shape can be acquired when the vehicle is moving or stationary.

[0088] Reference Figures 4 to 6 and Figure 8A , 8B According to the first embodiment, the image processing device 7 can be configured to implement a sequence for detecting the brightness of each pixel in each image acquired by the optical sensor 13, or to implement a sequence for detecting at least one dark area on each pixel in each image acquired by the optical sensor 13, in order to detect the shape 8. Therefore, the image processing device 7 can even detect traces of almost invisible or even colorless dirt, such as organic residue from insects. More specifically, the image processing device 7 is configured to implement an algorithm for executing one or more detection sequences.

[0089] In fact, even when shadows are present in the image acquired by optical sensor 13, the brightness of each pixel in the acquired image is approximately the same or nearly the same. Therefore, a significant decrease in brightness in some areas of the image acquired by optical sensor 13 can indicate the presence of stubborn contaminants on the outer surface 9b of optical element 9. Even in the case of colorless contaminants, this will diffract light and thus cause a decrease in brightness in some areas of the image acquired by optical sensor 13. Furthermore, if the detected decrease in brightness, or even the dark area, has a generally circular or semi-circular shape 8 centered on the rotation axis A1 of optical element 9, this indicates the presence of any contaminants. As previously stated, detecting this shape 8 indicates the presence of any contaminants. As an alternative embodiment or as an addition, image processing device 7 can be configured to implement a sequence for comparing a series of images acquired by optical sensor 13 with each other in order to detect said shape 8.

[0090] The contaminant detected by the image processing device 7 is located on the outer surface 9b of the optical element 9 of the protection device 3 (see also...). Figures 1 to 3 ).

[0091] Furthermore, in order to transmit the images acquired by the optical sensor 13 to the user of the motor vehicle, the image processing device 7 can be connected to at least one display component, such as screen 21 (in Figures 4 to 6 (Illustrated schematically) It is configured to display images acquired by optical sensor 13. This screen 21 can be arranged inside the passenger compartment of a motor vehicle, for example, on the center console.

[0092] In addition, at least one electronic control unit 11 is configured to communicate with the image processing device 7 and, when the shape 8 is detected by the image processing device 7, trigger at least one action to clean the outer surface 9b of the optical element 9.

[0093] More specifically, the image processing device 7 is configured to send at least one signal to at least one electronic control unit 11 indicating the presence of the shape 8, so as to allow at least one action for cleaning the outer surface 9b of the optical element 9 to be triggered when the shape 8 is detected.

[0094] Figures 4 to 6 A block diagram of the operation of the driver assistance system 1 according to various embodiments is shown, in particular a block diagram of cleaning the outer surface 9b of the optical element 9.

[0095] Image processing device 7 is connected to at least one electronic control unit 11. One or more electronic control units 11 are configured to trigger one or more cleaning actions. Furthermore, the same unit or another electronic control unit 11 can be configured to control actuator 5 to rotate optical element 9 (e.g., ...). Figures 1 to 3 (As shown).

[0096] As a non-limiting example, the electronic control unit 11 can command a change in the rotational speed of the optical element 9 to perform a cleaning action. More specifically, it can control the acceleration and deceleration of the optical element 9 to assist in the removal of any adhering dirt. Advantageously, the same electronic control unit 11 configured to control the actuator 5 is configured to command a change in the rotational speed of the optical element 9.

[0097] Furthermore, the cleaning action may also involve spraying a cleaning fluid (such as compressed air or cleaning liquid) onto the outer surface 9b of the optical element 9. For this purpose, the body element 2 has an opening to allow the nozzle 19 of the driver assistance system 1 to pass through (e.g., Figure 2(Illustrated schematically), and the electronic control unit 11 controls the nozzle 19 to trigger this cleaning action. According to a particular embodiment, when the cleaning action corresponds to spraying compressed air onto the outer surface 9b of the optical element 9, the nozzle 19 may be connected to a compressor (not shown) to spray compressed air onto the outer surface 9b. According to another embodiment, when the cleaning action corresponds to spraying cleaning fluid, the nozzle 19 may be connected to a cleaning fluid reservoir (not shown), such as a windshield washer fluid reservoir of a motor vehicle, to spray cleaning fluid onto the outer surface 9b of the optical element 9.

[0098] According to another alternative embodiment, the cleaning action may involve stopping the rotation of the optical element 9, which, in combination with the wiping component 23 (e.g., a wiping blade), removes any contaminants from the outer surface 9b by mechanical action, more specifically, by sweeping the outer surface 9b of the optical element 9. As for various other cleaning actions, the wiping component 23 is controlled by at least one electronic control unit 11. Furthermore, these different cleaning actions may optionally be combined, as described in further detail below.

[0099] The driver assistance system 1 may include a single electronic control unit 11 configured to command the actuator 5 to rotate the optical element 9 and perform one or more cleaning actions. Alternatively, the driver assistance system 1 may include a first electronic control unit 11 and one or more other electronic control units 11', the first electronic control unit 11 being specifically configured to control the actuator to rotate the optical element 9, and the one or more other electronic control units 11' being configured to perform cleaning actions. For example, the first electronic control unit 11 may be configured to control the actuator to rotate the optical element 9 and modify the rotation speed when performing such cleaning actions, and at least one additional electronic control unit 11' may be configured to perform cleaning actions, for example, corresponding to cleaning fluid sprayed onto the outer surface 9b of the optical element 9, or even to cleaning actions corresponding to the passage of the wiper component 23.

[0100] According to the first alternative embodiment ( Figure 4The driver assistance system 1 includes at least one first electronic control unit 11 and additional electronic control units 11', more specifically, two additional electronic control units 11'. The first electronic control unit 11 is configured to control the actuator 5 for rotating the optical element 9, and each of the additional electronic control units 11' is configured to trigger at least one cleaning action, i.e., spraying cleaning fluid or stopping the rotation of the optical element 9 to command the wiper component 23 to pass over its outer surface 9b, or even modify the rotational speed of the optical element 9. Alternatively, the two cleaning actions can be combined, particularly the spraying of cleaning fluid and the passage of the wiper component 23. Thus, the driver assistance system 1 includes a first electronic control unit 11 configured to control the actuator 5 and additional electronic control units 11' for each cleaning component that allow at least one cleaning action to be performed. The image processing device 7 can be configured to notify the additional electronic control units 11' of the presence of a generally circular or semi-circular shape 8 centered on the rotation axis A1 of the optical element 9 to allow the first cleaning action, such as spraying cleaning fluid, and then optionally allow the second cleaning action if necessary.

[0101] According to the second alternative embodiment ( Figure 5 The same electronic control unit 11 is configured to trigger one or more cleaning actions and control the actuator 5 to rotate the optical element 9. Therefore, the driver assistance system 1 can include a limited number or even a single electronic control unit 11, which allows for a limitation on the number of components in the driver assistance system 1, thus compared to the reference... Figure 4 Compared to the first alternative embodiment described, it allows for limitations in size and cost.

[0102] According to these first ( Figure 4 ) and the second ( Figure 5 In an alternative embodiment, at least one electronic control unit 11, image processing device 7, and optical sensor 13 are separate components.

[0103] According to the third alternative embodiment ( Figure 6 The optical sensor 13 includes an image processing device 7. (See reference...) Figure 4 The optical sensor 13 is connected to the electronic control unit 11 or various electronic control units 11, 11'. More specifically, the optical sensor 13 is adapted to send signals to the unit or each electronic control unit 11, particularly in the absence of an additional intermediate image processing device 7, as shown in the reference. Figure 4 and 5 As shown. The optical sensor 13 can also be connected to the screen 21. This could involve direct communication, whereby the optical sensor 13 transmits the acquired image to the screen 21 without going through additional image processing devices, as shown in the reference. Figure 4 and 5 As shown.

[0104] According to this third alternative embodiment, the driver assistance system 1 includes a single electronic control unit 11 for controlling the actuator 5 to rotate the optical element 9, and optionally, ensuring at least one cleaning action when this involves modifying the rotational speed of the optical element 9, and also for controlling the nozzle 19 or the wiper component 23 when the driver assistance system 1 includes such an element.

[0105] According to an alternative embodiment not shown herein, the driver assistance system 1 may include an image processing device 7 integrated in an optical sensor 13, a first electronic control unit 11 configured to control the rotation of an optical element 9, and at least one additional electronic control unit 11' configured to control at least one cleaning action.

[0106] The use of the optical sensor 13, which includes the image processing device 7, allows for a limitation on the number of components in the driver assistance system 1, and thus limits its size. In fact, no additional image processing device is required besides those already embedded in the optical sensor 13.

[0107] According to an alternative embodiment not shown herein, the driver assistance system 1 includes a single electronic control unit 11, in which an image processing device 7 is integrated. Therefore, an additional image processing device 7 communicating with the optical sensor 13 and the electronic control unit 11 is not required to control one or more cleaning actions. According to this alternative embodiment, the electronic control unit 11 is configured to control the rotational speed of the optical element 9 and also to control one or more cleaning actions. Furthermore, according to this alternative embodiment, the electronic control unit 11 can be connected to a screen 21 to transmit images acquired by the optical sensor 13 to the user of the vehicle when necessary, such as during parking maneuvers.

[0108] refer to Figure 7 The diagram shows a flowchart illustrating the operation of the aforementioned driver assistance system 1, and more specifically, it shows a method for cleaning the protective device 3 of the optical sensor 13, particularly the optical element 9.

[0109] The method includes step E1, which initiates the rotation of optical element 9 to remove any contaminants, such as dust, that might accumulate on it via centrifugal effect. This E1 step, initiating the rotation, can be performed when the vehicle is started or once optical sensor 13 is triggered. Optical element 9 is initiated to rotate via actuator 5 (see [link to relevant documentation]). Figure 3 Furthermore, at least during the operation of the driver assistance system 1, the optical element 9 remains rotated to remove any water droplets or dirt that may have deposited on it through centrifugal effect, thereby ensuring that the optical sensor 13 (specifically as shown in the image) can effectively remove the contaminants. Figures 1 to 3The quality of the images acquired (as shown) ensures the correct operability of the driver assistance system 1.

[0110] The method includes step E2, in which the optical sensor 13 acquires a series of images. This step E2, in which the optical sensor 13 acquires images, can be performed whether the vehicle is moving or stationary.

[0111] The method then includes step E3, which involves processing a series of images acquired by the optical sensor 13 as the optical element 9 rotates, to detect a generally circular or semi-circular shape 8 centered on the rotation axis A1 of the optical element 9 (e.g., ...) on the acquired images. Figure 8A (As shown). This shape 8 is detected in the image acquired by the optical sensor 13 even when the vehicle is stationary, allowing the identification of the presence of dirt on the outer surface 9b of the optical element 9, since it has been found that this shape is unlikely to be detected when there is no dirt on the outer surface 9b.

[0112] The image processing device 7 of the driver assistance system 1 is used to perform step E3, which processes a series of images. As previously described, the image processing device 7 can be included in the electronics of the optical sensor 13, as shown in the reference. Figure 6 As shown, they may be included in at least one electronic control unit 11 of the driver assistance system 1, or they may even be separate from the optical sensors 13 and the electronic control unit 11, as shown in the reference. Figure 4 and 5 As shown.

[0113] Step E3, which processes a series of images, may include at least one sequence from a sequence used to detect brightness or darkness, or even a sequence used to compare the images acquired by the optical sensor 13 during step E2, as previously described.

[0114] After step E3, which processes a series of images, the method may include step E4, which sends a signal to at least one electronic control unit 11 indicating the absence (step E5') or presence (step E5) of a generally circular or semi-circular shape 8 centered on the rotation axis A1 of the optical element 9.

[0115] Regardless of the outcome of step E3, which processes a series of images, the various images acquired by optical sensor 13 can be transmitted to the passengers of the motor vehicle during step E7, which displays the acquired images. Specifically, these acquired images are displayed on screen 21 arranged inside the passenger compartment of the motor vehicle (schematically shown in...). Figures 4 to 6 (as shown in the image), for example, as referenced. Figure 8A and 8B As shown. More specifically, Figure 8ACorresponding to the image acquired by the optical sensor 13, which has a generally circular or semi-circular shape 8 centered on the rotation axis A1 of the optical element 9, it reflects the presence of any dirt. Furthermore, Figure 8B This corresponds to an image without any dirt or grime. Therefore, Figure 8A The image displayed on screen 21 corresponds to the image shown when the electronic control unit 11 is notified that there is dirt on the outer surface 9b of the optical element 9 (step E5). Figure 8B This corresponds to the image displayed on screen 21 when the electronic control unit 11 is notified that there is no dirt on the outer surface 9b of the optical element 9 (step E5'). The cleaning method will not impair the use of the driver assistance system 1 if required by the vehicle user.

[0116] When, for example, a signal indicating the presence of a generally circular or semi-circular shape 8 is received via the electronic control unit 11, the method implements step E6, which triggers at least one action for cleaning the outer surface 9b of the optical element 9. In other words, detecting the generally circular or semi-circular shape 8 during step E5 allows the cleaning step E6 to be triggered automatically. Therefore, the operability of the optical sensor 13 is improved because the outer surface 9b of the optical element 9 is cleaned once the generally circular or semi-circular shape 8 is detected, so that the outer surface 9b of the optical element 9 is cleaned before the image acquired by the optical sensor 13 may be displayed on the screen 21.

[0117] As previously described, the cleaning action can be, for example, an action to modify the rotational speed E6a of the optical element 9. This modification of the rotational speed E6a of the optical element 9 can correspond to an acceleration of that rotational speed, or even to its acceleration and deceleration phases, in order to allow any contaminants on the outer surface 9b of the optical element 9 to lose their adhesion and thus be removed. These acceleration and deceleration phases can optionally correspond to rapid changes in the rotational direction of the optical element 9.

[0118] As an alternative embodiment or additionally, the cleaning action may involve, for example, spraying E6b cleaning fluid. This spraying step E6b can be performed while the optical element 9 is fixed or rotated.

[0119] More specifically, and optionally, according to the reference Figure 7 In the specific embodiment shown, when the cleaning action corresponds to step E6b of spraying cleaning fluid, the method advantageously includes a drying step E6b' during which the optical element 9 is set to begin rotating. This can occur, for example, between a new iteration of one or more cleaning actions E6 and step E2 of acquiring a series of images. The drying step E6b' allows the cleaning liquid used, as well as optional contaminants that may have deposited on the optical element 9, to be removed immediately after the cleaning action.

[0120] Furthermore, a drying step E6b' can be performed to allow any liquids (e.g., water, melted snow, or even hydrocarbons) on the outer surface 9b of the optical element 9 to be removed, particularly immediately after the cleaning action. This avoids detecting traces of dirt that do not correspond to stubborn or crusted deposits. However, according to other embodiments not described herein, this drying step E6b' can be performed for a duration exceeding 3 seconds.

[0121] According to yet another alternative embodiment, or additionally, the cleaning action may include actions to stop the rotation of the optical element and actions to make the wiping component 23 (such as...) Figure 6 (As shown) The combination of action E6c through the outer surface 9b of optical element 9.

[0122] These different cleaning actions can be combined. Depending on the cleaning action performed, it can be performed while the optical element 9 is fixed or rotating, especially when it involves spraying cleaning fluid, thus making the cleaning method versatile.

[0123] Furthermore, after triggering at least one cleaning action E6, the steps of acquiring a series of images (E2) and processing the acquired images (E3) are repeated at least once. Therefore, the effectiveness of the cleaning can be checked, and optionally, an additional step E6 triggering at least one cleaning action can be initiated to remove any contaminants that may still be present on the outer surface 9b of the optical element 9.

[0124] If the image processing device 7 no longer detects the approximately circular or semi-circular shape 8, it is not necessary to repeat step E6, which involves triggering at least one cleaning action. The result of step E4, which sends a signal to at least one electronic control unit 11, will correspond to the absence of detection of the shape 8 (step E5').

[0125] While the shape 8 is still detected by the image processing device 7, step E6, which triggers at least one cleaning action, is repeated to perform a second cleaning cycle. In this case, cleaning operations can be combined. It is conceivable that the first cleaning action corresponds to step E6a, which modifies the rotational speed of the optical element 9. Since the presence of the shape 8 is still detected, this indicates that the cleaning action E6a, used to modify the rotational speed, is insufficient to remove any contaminant. In practice, such contaminant may sometimes need to be wetted, for example, using a cleaning liquid, to promote, for example, loss of adhesion to the outer surface 9b of the optical element 9, or to initiate its fragmentation to facilitate its removal. Therefore, as the second step E6, which triggers at least one cleaning action, the cleaning method can implement step E6b, which involves spraying a cleaning fluid (e.g., a cleaning liquid), to wet the contaminant, followed by step E6a, which modifies the rotation of the optical element 9, to remove the wetted contaminant. Alternatively, these steps E6b, which involve spraying a cleaning fluid, and E6a, which modifies the rotational speed of the optical element 9, can be implemented together.

[0126] According to another alternative embodiment, when a second step E6 is required to trigger at least one cleaning action, the triggering step E6 may include a first step E6b of spraying cleaning liquid, followed by a step E6c of passing the wiping component 23 across the outer surface 9b of the optical element 9 when the element stops, so as to allow mechanical cleaning of the outer surface 9b. Therefore, the electronic control unit 11 can control the combination of cleaning actions jointly or sequentially.

[0127] In the above method, reference is made to the electronic control unit 11. This method can be implemented, for example, by referring to... Figure 5 and 6 The method is implemented using the driver assistance system 1 shown. As an alternative embodiment, the method can be implemented using a driver assistance system 1, which includes a first electronic control unit 11 and one or more additional electronic control units 11', as shown in the reference... Figure 4 As shown.

[0128] The cleaning method described above can be performed whether the vehicle is moving or stationary. This provides versatility for cleaning the optical element 9, without being limited by the requirement that the vehicle must be moving. Therefore, this ensures that the driver assistance system 1 can operate correctly when needed by the user of the vehicle.

[0129] The foregoing embodiments are examples provided by way of non-limiting illustration. In practice, those skilled in the art can certainly use other types of actuators 5 besides motors to rotate the optical element 9 without departing from the scope of the invention. Furthermore, those skilled in the art can perform cleaning actions other than those described above without departing from the scope of the invention. Moreover, those skilled in the art can combine some steps of the above-described cleaning method, or even interchange some steps of the cleaning method, without departing from the scope of the invention.

[0130] Therefore, by means of the aforementioned driver assistance system 1 which implements the cleaning method, it is possible to obtain a cleaning method for a protective device 3 for an optical sensor 13 of a motor vehicle, which allows for effective automatic cleaning of the optical element 9 arranged upstream of the optical sensor 13, and the method is simple to implement and has a dirt detection step that can be performed even when the motor vehicle is stationary.

Claims

1. A cleaning method for cleaning a protective device (3) of a driver assistance system (1) for a motor vehicle, the driver assistance system (1) including an optical sensor (13) having an optical element (14), and the protective device (3) having an optical element (9) disposed upstream of the optical element (14), the optical element (9) having an inner surface (9a) facing the optical element (14) and an outer surface (9b) opposite to the inner surface (9a), and being movably mounted about a rotation axis (A1). in, The method includes the following steps: • Processing (E3) a series of images acquired by the optical sensor (13) as the optical element (9) rotates, in order to detect on the acquired images a generally circular or semi-circular shape (8) formed by contaminants deposited on the outer surface (9b) of the optical element (9) centered on the axis of rotation (A1) of the optical element (9); and • If the shape (8) is detected, at least one action (E6) is triggered to clean the outer surface (9b) of the optical element (9).

2. The cleaning method according to claim 1, wherein, The process of processing (E3) a series of images is carried out by means of the image processing device (7) of the driver assistance system (1).

3. The cleaning method according to claim 1 or 2, wherein, The steps of processing (E3) a series of images include at least one of the following sequences: a sequence for detecting the brightness of each pixel of each image acquired by the optical sensor (13); a sequence for detecting at least one dark area on each pixel of each image acquired by the optical sensor (13); or a sequence for comparing the series of images acquired by the optical sensor (13) with each other.

4. The cleaning method according to claim 1 or 2, wherein, After triggering at least one cleaning action (E6), repeat the process (E3) of a series of images at least once.

5. The cleaning method according to claim 1 or 2, wherein, The at least one cleaning action is performed when the optical element (9) is stationary.

6. The cleaning method according to claim 1 or 2, wherein, The at least one cleaning action is performed when the optical element (9) rotates.

7. The cleaning method according to claim 1 or 2, wherein, The at least one cleaning action is selected from an action of modifying the rotational speed of the optical element (9) (E6a), an action of spraying cleaning fluid (E6b), an action of stopping the rotation of the optical element, and an action of causing the wiping component (23) to pass over the outer surface (9b) of the optical element (9) (E6c), or even a combination of these actions.

8. The cleaning method according to claim 7, wherein, The cleaning method includes a drying step (E4b'), during which the optical element (9) is set to begin rotating.

9. The cleaning method according to claim 7, wherein, The cleaning fluid is a cleaning liquid or compressed air.

10. The cleaning method according to claim 7, wherein, The wiping component (23) is a wiping blade.

11. A driver assistance system (1) for a motor vehicle, comprising an optical sensor (13) and a protective device (3) for said optical sensor (13), said optical sensor (13) having an optical element (14) and configured to acquire at least one image, said protective device (3) comprising: • Optical element (9), arranged upstream of the optical device (14) of the optical sensor (13) and movably mounted about the rotation axis (A1), the optical element (9) having an inner surface (9a) facing the optical device (14) and an outer surface (9b) opposite to the inner surface (9a). and • Actuator (5), configured to rotate the optical element (9); The driver assistance system (1) includes: - An image processing device (7) is configured to process a series of images acquired by the optical sensor (13) as the optical element (9) rotates, in order to detect a generally circular or semi-circular shape (8) centered on the rotation axis (A1) of the optical element (9) caused by contaminants deposited on the outer surface (9b) of the optical element (9); and - At least one electronic control unit (11) is configured to communicate with the image processing device (7) and trigger at least one action for cleaning the outer surface (9b) of the optical element (9) when the shape (8) is detected by the image processing device (7).

12. The driver assistance system (1) according to claim 11, wherein, The optical sensor (13) includes the image processing device (7).

13. The driver assistance system (1) according to claim 11 or 12, wherein, An electronic control unit (11) configured to trigger the at least one cleaning action is configured to control an actuator (5) for rotating the optical element (9).

14. The driver assistance system (1) according to claim 11 or 12, wherein, The driver assistance system also includes at least one nozzle (19) configured to spray cleaning fluid onto the outer surface (9b) of the optical element (9) when the at least one cleaning action is triggered.

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