FR3138698A1 - System for automatically measuring the optical quality of a given area of vehicle glazing, method of implementing such a system and production line comprising this system - Google Patents

Abstract

System for automatically measuring the optical quality of a given area of vehicle glazing, method of implementing such a system and production line comprising this system One aspect of the invention relates to a system (100) for automatically measuring the optical quality of a given zone (12) of vehicle glazing (140), comprising: a device (120) for emitting and receiving a beam of light rays, positioned facing a first main face (10a) of the glazing and configured to emit the beam of light rays in the direction of the given zone (12 ) and to receive said beam of light rays transmitted by this given zone, a device (130) for reflecting the light rays, positioned facing a second main face (10b) of the glazing, a support (110) comprising a first end (111) on which the transmitting and receiving device (120) is mounted and a second end (112) on which the reflection device (130) is mounted, and a unit (150) for controlling movements of the support, configured to control simultaneous movements of the transmitting and receiving device (120) and the reflection device (130) relative to the given area of the glazing. Another aspect of the invention relates to a measurement method that can be implemented on the measurement system. Yet another aspect concerns a production line integrating this measurement system. Figure to be published with the abstract: Figure 1

Description

System for automatically measuring the optical quality of a given area of vehicle glazing, method for implementing such a system and production line comprising this system TECHNICAL FIELD OF THE INVENTION

The present invention relates to a system for automatically measuring the optical quality of a given area of a vehicle glazing designed to be installed within a vehicle glazing production line. The invention also relates to a production line comprising this system as well as a method for implementing this system.

The invention finds applications in the field of land vehicles and, in particular, in the fields of driving assistance and autonomous vehicles.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

More and more land transport vehicles, and in particular road vehicles such as cars and trucks, are equipped with intelligent driver assistance systems (called ADAS, for Advanced Driver Assistance System, in English terminology) to limit the risk of accidents and make driving easier for drivers. These ADAS systems are also designed to equip driverless vehicles, known as "autonomous vehicles".

These ADAS systems are embedded systems that provide various information in real time (such as the state of road traffic), detect and anticipate possible threats from the vehicle's external environment, or help the driver to perform difficult or risky maneuvers, such as overtaking other vehicles or parking. To do this, these ADAS systems include numerous detection devices, or sensors, to collect data on the vehicle's environment. Some systems, such as parking assistance systems, autonomous driving systems or collision anticipation systems, also implement one or more image acquisition devices, or cameras.

The data acquired by these image acquisition devices are processed by ADAS systems, also called embedded systems, to obtain the desired functionality. For example, a night driving assistance system can display a video of the outside environment in real time on the vehicle's dashboard via an infrared camera placed behind the vehicle's windshield. In another example, an autonomous driving system processes the images acquired by a camera placed behind the vehicle's windshield in order to extract the data necessary for the vehicle's automatic piloting.

Generally, image acquisition devices are arranged inside the vehicle and generally positioned behind one of the vehicle's windows, such as the windshield, the rear window or the side windows, so as to be protected from external elements such as rain, hail, flying stones, etc. Most of these image acquisition devices are arranged behind the windshield to enable the acquisition of information relating to the environment located in front of the vehicle. The data acquired by the on-board systems, and in particular the images, are therefore obtained through the glazing. Indeed, from an optical point of view, the positioning of the image acquisition devices behind the windshield is such that the light rays received by these image acquisition devices first pass through the glazing before reaching said devices. The glazing must therefore have optimal optical quality or at least sufficient to prevent the image captured by the image acquisition device from being distorted.

However, glazing often has optical defects with various origins. One of the characteristics causing optical defects is the inclination of the glazing. Indeed, most vehicle glazing, particularly windshields and rear windows, are inclined; the optical beams passing through these glazings can therefore be deformed by this inclination of the glazing. Another characteristic causing optical defects is the area of the glazing called the "camera zone" which includes opaque elements intended in particular to hide part of the elements of the image acquisition devices so that they are not visible from outside the vehicles. These opaque elements, most often made of enamel, in fact cause a reduction in the optical quality of the camera zone of the glazing at the level of the area bordering the opaque elements, particularly in the area of the glazing located at a distance of between 5 and 8 mm from the opaque elements. Furthermore, in the specific case of areas delimited by enamel deposited at high temperature on glass glazing, differences in the coefficient of thermal expansion or physicochemical interactions between the materials of the enamel and the glass may cause local variations in the surface near their edges, such as variations in the refractive index and/or geometric deformations relative to the rest of the surface of the glazing. In addition, areas delimited by opaque elements may also include, on their surface, functional elements (such as networks of heating wires or functional layers with optical or thermal properties) which are directly placed in the acquisition field of the image acquisition devices and which generate optical defects.

When building a vehicle, the glazing is always positioned on the vehicle before the ADAS system. The glazing is therefore manufactured before the image acquisition device is integrated. Thus, it is necessary to check the optical quality of the camera area of the glazing, and in particular the camera area, before the glazing is mounted on the vehicle in order to avoid the presence of optical defects causing harmful artifacts in the acquired images. For economic reasons, it could be interesting to integrate the measurement of the optical quality of the camera area of a glazing on a glazing production line so that each glazing can be checked before the end of its manufacture.

A known method for measuring the optical quality of glazing, particularly vehicle windshields, is deflectometry, which measures the refraction of the glazing. This method uses a screen, positioned on one side of the glazing and whose position of each emitting point is known, and a CCD sensor, positioned on the other side of the glazing. However, this measurement method only allows the distortion introduced by the glazing to be determined and does not allow the optical defects that alter the quality of the image captured using this method to be identified and quantified precisely. This method also does not allow the optical quality of a small area of glazing to be measured, particularly when opaque elements surrounding said area cause optical distortions in their vicinity. Indeed, this method has a spatial resolution such that the optical quality measurements are limited to a portion of the surface of said given area.

Another measurement method, disclosed in patent document WO 2021/110901 A1 filed in the name of the applicant, proposes to determine the optical quality of a given region using a wavefront analyzer. This analyzer makes it possible to analyze the wavefront of the light rays emitted by a light ray emitter through the camera area of the glazing. This technique has the advantage of being particularly efficient for measuring the optical quality of a given area of a glazing. However, it is manual and requires a specific adjustment for each glazing. However, on a production line, a movement rail transports the glazings one after the other, regardless of the models, in the different manufacturing blocks of the line. In other words, on the production line, the glazing models are mixed on the production line and pass one after the other. As each glazing model requires a specific adjustment, the method disclosed in this patent document cannot be integrated as is on a production line to measure the optical quality of the camera zone of the different glazing models passing one after the other.

There is therefore a real need for a technique to automate the measurement of optical quality, by wavefront analysis, on a production line.

To address the above-mentioned problems of automating the measurement of the optical quality of the camera zone of a glazing unit on a production line, the applicant proposes a measurement system in which a device for emitting and receiving a beam of light rays is mounted in one zone of a support and a device for reflecting the light rays is mounted in another zone of the support, the two zones being opposite and each facing a different face of the glazing unit. The applicant also proposes a method for implementing this system.

In the remainder of the description, the term “camera” will mean any image-taking device designed to be installed inside a vehicle, facing the glazing of said vehicle, including stereovision cameras and devices commonly called LiDAR (for Light Detection And Ranging, in English terminology). Thus, the method and the system of the invention described below for a camera zone are suitable for the case where the vehicle is equipped with a LiDAR, the camera zone then being a LiDAR zone whose specific features are described later.

In the remainder of the description, we will speak indifferently of glazing and windshield, it being understood that the invention described for a windshield can be implemented for any type of glazing equipped with a camera zone (in the visible) and/or a LiDAR zone.

• un dispositif d’émission et de réception d’un faisceau de rayons lumineux défini pour couvrir la zone donnée, le dispositif d’émission et de réception étant positionné en regard d’une première face principale du vitrage et configuré pour émettre le faisceau de rayons lumineux en direction de la zone donnée et pour recevoir ledit faisceau de rayons lumineux transmis par cette zone donnée, ledit dispositif d’émission et de réception comportant un émetteur de faisceau de rayons lumineux et un analyseur de fronts d’ondes configuré pour analyser le front d’onde des rayons lumineux transmis par la zone donnée,
• un dispositif de réflexion des rayons lumineux, positionné en regard d’une deuxième face principale du vitrage et configuré pour renvoyer le faisceau de rayons lumineux vers le dispositif d’émission et de réception, le dispositif d’émission et de réception et le dispositif de réflexion étant alignés suivant un axe optique,
• un support, mobile, s’étendant au moins de la première face principale du vitrage jusqu’à la deuxième face principale du vitrage et sur lequel sont montés le dispositif d’émission et de réception et le dispositif de réflexion, ledit dispositif de réflexion étant ainsi solidaire du dispositif d’émission et de réception, et
• une unité de commande de déplacements du support, configurée pour contrôler des déplacements simultanés du dispositif d’émission et de réception et du dispositif de réflexion par rapport à la zone donnée du vitrage.

According to a first aspect, the invention relates to a system for automatically measuring the optical quality of a given area of vehicle glazing, comprising:

• a device for emitting and receiving a beam of light rays defined to cover the given area, the emitting and receiving device being positioned opposite a first main face of the glazing and configured to emit the beam of light rays towards the given area and to receive said beam of light rays transmitted by this given area, said emitting and receiving device comprising a light ray beam emitter and a wavefront analyzer configured to analyze the wavefront of the light rays transmitted by the given area,
• a device for reflecting light rays, positioned opposite a second main face of the glazing and configured to return the beam of light rays towards the emission and reception device, the emission and reception device and the reflection device being aligned along an optical axis,
• a mobile support extending at least from the first main face of the glazing to the second main face of the glazing and on which the emission and reception device and the reflection device are mounted, said reflection device thus being integral with the emission and reception device, and
• a support movement control unit, configured to control simultaneous movements of the transmitting and receiving device and the reflecting device relative to the given area of the glazing.

This system allows to measure automatically, with good reliability, the optical quality of the camera zones of various models of glazing moving on a production line. It allows, in fact, to adapt the measurement to the glazing, whatever the model of glazing. It also allows to carry out the measurement in a limited time. It also allows to ignore any dust.

Furthermore, due to the solidification of the device for emitting and receiving the beam of light rays and the reflection device, the system according to the invention makes it possible to ignore possible vibrations and to obtain qualitative measurements even in the presence of vibrations.

Advantageously, the support is an open structure comprising a first zone on which the transmission and reception device is mounted and a second zone on which the reflection device is mounted, said first and second zones being diametrically opposed.

• un dispositif d’émission d’un faisceau de rayons lumineux défini pour couvrir la zone donnée, le dispositif d’émission étant positionné en regard d’une première face principale du vitrage (notamment face avant) et configuré pour émettre le faisceau de rayons lumineux en direction de la zone donnée,
• un dispositif de réception des rayons lumineux, positionné en regard d’une deuxième face principale du vitrage (notamment face arrière) et comportant un analyseur de fronts d’ondes configuré pour réceptionner le faisceau de rayons lumineux transmis par la zone donnée et analyser le front d’onde desdits rayons lumineux, le dispositif de réception et le dispositif d’émission étant alignés suivant un axe optique,
• un support, mobile, s’étendant au moins de la première face principale du vitrage jusqu’à la deuxième face principale du vitrage et sur lequel sont montés le dispositif d’émission et le dispositif de réception, ledit dispositif de réception étant ainsi solidaire du dispositif d’émission, et
• une unité de commande de déplacements du support, configurée pour contrôler des déplacements simultanés du dispositif d’émission et du dispositif de réception par rapport à la zone donnée du vitrage.

According to another embodiment, the system for automatically measuring the optical quality of a given area of vehicle glazing comprises:

• a device for emitting a beam of light rays defined to cover the given area, the emitting device being positioned opposite a first main face of the glazing (in particular the front face) and configured to emit the beam of light rays towards the given area,
• a device for receiving light rays, positioned opposite a second main face of the glazing (in particular the rear face) and comprising a wavefront analyzer configured to receive the beam of light rays transmitted by the given zone and analyze the wavefront of said light rays, the receiving device and the emitting device being aligned along an optical axis,
• a mobile support extending at least from the first main face of the glazing to the second main face of the glazing and on which the emission device and the reception device are mounted, said reception device thus being integral with the emission device, and
• a support movement control unit, configured to control simultaneous movements of the transmitting device and the receiving device relative to the given area of the glazing.

This embodiment of the system of the invention has the same advantages as those described for the first embodiment.

The transmitting or receiving device or the transmitting device may comprise a transmitter comprising a light source and a collimator placed after the light source, along the optical axis, in order to obtain a beam of light rays, for example parallel. Advantageously, the light source of the transmitter is monochromatic and adapted to emit in the visible or near infrared range, i.e. in the wavelengths between 400 nm and 1200 nm, preferably between 620 nm and 950 nm, so that the system of the invention can be used for any camera zone in the visible or near infrared. The transmitter may have two monochromatic light sources adapted to emit in the visible and near infrared ranges.

The beam of light rays may cover at least the transparent surface of the camera area but it may cover a wider area than the camera area, which is the area intended to be coupled to the vehicle camera. In particular, the beam of light rays in the visible range covers at least the transparent surface of the camera area in the visible range but it may cover a wider area than the camera area in the visible range, which is the area intended to be coupled to the vehicle camera in the visible range.

Advantageously, the support, in this embodiment, is an open structure comprising a first zone on which the transmission device is mounted and a second zone on which the reception device is mounted, said first and second zones being diametrically opposed.

The beam of light rays can cover the given area once (one measurement) or twice or more (one or more measurements), especially if the given area is large enough. The beam can thus cover partial areas positioned side by side, with a possible overlap (two by two) of said partial areas as detailed later in particular for LiDAR area.

• l’unité de commande des déplacements comporte des moyens de déplacements en translation (suivant une direction verticale du support) et/ou des moyens de déplacements angulaires dudit support.
• le support a une forme courbée s’étendant au moins de la première face principale du vitrage jusqu’à la deuxième face principale du vitrage, à distance de l’unité de commande des déplacements.
• le support a une forme de C.
• le support comporte deux branches dans des plans sensiblement parallèles l’un à l’autre , entre lesquelles sont fixées, à chacune des première et deuxième zones, une embase configurée pour supporter, respectivement, le dispositif d’émission et de réception et le dispositif de réflexion ou le dispositif d’émission et le dispositif de réception.
• le support est monté sur un bâti contrôlé par l’unité de commande et configuré pour déplacer le support en translation suivant une direction verticale et/ou en rotation suivant une direction angulaire.
• le bâti comporte une table de translation verticale montée sur des vérins et des premier et deuxième bras de rotation fixés d’une part sur le support et d’autre part sur la table de translation verticale.
• la première zone du support est positionnée à proximité de l’unité de commande, la deuxième zone étant positionnée à distance de ladite unité de commande.
• il s’étend au moins partiellement autour d’un dispositif de maintien et de déplacement du vitrage d’une ligne de production de vitrages.
• le dispositif de maintien et de déplacement du vitrage comporte au moins un rail de déplacement dudit vitrage, caractérisé en ce que le support s’étend au moins partiellement autour du rail de déplacement.
• le dispositif de réflexion comporte un miroir-plan.

In addition to the characteristics which have just been mentioned in the preceding paragraph, the measuring system according to these two embodiments of the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations:

• the movement control unit comprises means for translational movement (in a vertical direction of the support) and/or means for angular movement of said support.
• the support has a curved shape extending at least from the first main face of the glazing to the second main face of the glazing, at a distance from the movement control unit.
• the support has a C shape.
• the support comprises two branches in planes substantially parallel to each other, between which are fixed, to each of the first and second zones, a base configured to support, respectively, the transmission and reception device and the reflection device or the transmission device and the reception device.
• the support is mounted on a frame controlled by the control unit and configured to move the support in translation in a vertical direction and/or in rotation in an angular direction.
• the frame comprises a vertical translation table mounted on jacks and first and second rotation arms fixed on the one hand to the support and on the other hand to the vertical translation table.
• the first area of the support is positioned near the control unit, the second area being positioned at a distance from said control unit.
• it extends at least partially around a device for holding and moving the glazing of a glazing production line.
• the device for holding and moving the glazing comprises at least one rail for moving said glazing, characterized in that the support extends at least partially around the moving rail.
• the reflection device comprises a plane mirror.

• a) positionnement en translation verticale d’un système de mesure automatique de la qualité optique de la zone donnée du vitrage, ledit système comportant un support sur lequel sont montés, à distance l’un de l’autre, soit un dispositif d'émission et de réception défini pour couvrir la zone donnée, comportant un émetteur de faisceau de rayons lumineux et un analyseur de fronts d’ondes et un dispositif de réflexion des rayons lumineux, soit un dispositif d’émission et un dispositif de réception des rayons lumineux comportant un analyseur de fronts d’ondes,
• b) positionnement angulaire du système de mesure automatique de la qualité optique de la zone donnée du vitrage, le positionnement translatif et/ou le positionnement angulaire étant définis de sorte que, d’une part, le dispositif d’émission et de réception et le dispositif de réflexion, ou le dispositif d’émission et le dispositif de réception, soient alignés suivant un même axe optique et, d’autre part, que la zone donnée soit couverte par un faisceau de rayons lumineux émis par le dispositif d’émission et de réception, les opérations a) et b) étant dans n’importe quel ordre (et sont suivies de)
• c) mesure de la qualité optique de la zone donnée.

A second aspect of the invention relates to a method for automatically measuring the optical quality of a given area of vehicle glazing in a glazing production line, in particular which is implemented in the measuring system according to the invention as described above which comprises the following operations:

• (a) positioning in vertical translation of a system for automatically measuring the optical quality of the given area of the glazing, said system comprising a support on which are mounted, at a distance from each other, either a transmission and reception device defined to cover the given area, comprising a light beam transmitter and a wavefront analyzer and a light ray reflection device, or a light ray transmission device and a light ray reception device comprising a wavefront analyzer,
• (b) angular positioning of the automatic optical quality measuring system of the given area of the glazing, the translational positioning and/or the angular positioning being defined so that, on the one hand, the emitting and receiving device and the reflecting device, or the emitting device and the receiving device, are aligned along the same optical axis and, on the other hand, the given area is covered by a beam of light rays emitted by the emitting and receiving device, operations (a) and (b) being in any order (and are followed by)
• c) measurement of the optical quality of the given area.

This measuring method has the advantage of being able to be implemented in a glazing production line, for various glazing models while offering good quality and good reliability of measurements. The angular positioning of the measuring system can be planned before the vertical translation positioning.

• l’opération c) de mesure de la qualité optique de la zone donnée est réalisée pour un vitrage positionné à un angle d’installation sur véhicule.
• il comporte, après l’opération c), une opération d’enregistrement en temps réel des données de qualité optique mesurées.
• l’opération c) de mesure de la qualité optique comporte une étape de détection de la zone donnée du vitrage dans une zone du vitrage couverte par un analyseur de front d’onde et comprenant ladite zone donnée.
• l’opération c) de mesure de la qualité optique de la zone donnée comporte :
  • une étape d’émission, par le dispositif d’émission et de réception ou le dispositif d’émission, d’un faisceau de rayons lumineux en direction de la zone donnée, et
  • une étape d’analyse, par l’analyseur de front d’ondes, du front d'ondes des rayons lumineux transmis par la zone donnée avec la génération d’une carte d’erreur de front d’ondes et, à partir de ladite carte d’erreur de front d’ondes, une détermination d’au moins une carte des défauts optiques présents dans la zone donnée du vitrage.
• la zone donnée comporte au moins deux zones partielles positionnées côte à côte, avec un éventuel recouvrement (deux à deux) desdites zones partielles, la qualité optique de chaque zone partielle étant mesurée successivement par le système tel que défini ci-dessus, après déplacement de préférence du vitrage sur la ligne de production (translation horizontale), en particulier la zone donnée étant une zone LiDAR, le faisceau de rayons lumineux étant dans le proche infrarouge.
• l’opération c) de mesure de la qualité optique est mise en œuvre pour une première zone donnée, par exemple une zone caméra dans le visible avec le (premier) faisceau (monochromatique, collimaté) de rayons lumineux dans le visible, et réitérée pour une deuxième zone donnée, par exemple une zone LiDAR avec le (deuxième) faisceau (monochromatique, collimaté) de rayons lumineux dans le proche infrarouge, la deuxième zone donnée étant de préférence positionnée à côté de la première zone donnée, notamment les première et deuxième zones données sont une zone caméra dans le visible et une zone LiDAR,
• il est mis en œuvre pendant une durée inférieure à un temps de cycle de la ligne de production.

The measuring method according to the second aspect of the invention may have one or more complementary characteristics among the following, considered individually or in all technically possible combinations:

• operation c) of measuring the optical quality of the given area is carried out for glazing positioned at an installation angle on the vehicle.
• it includes, after operation c), a real-time recording operation of the measured optical quality data.
• operation c) of measuring the optical quality comprises a step of detecting the given area of the glazing in an area of the glazing covered by a wavefront analyzer and comprising said given area.
• operation c) of measuring the optical quality of the given area includes:
  • a step of emitting, by the emitting and receiving device or the emitting device, a beam of light rays towards the given area, and
  • a step of analysis, by the wavefront analyzer, of the wavefront of the light rays transmitted by the given zone with the generation of a wavefront error map and, from said wavefront error map, a determination of at least one map of the optical defects present in the given zone of the glazing.
• the given area comprises at least two partial areas positioned side by side, with a possible overlap (two by two) of said partial areas, the optical quality of each partial area being measured successively by the system as defined above, after preferably moving the glazing on the production line (horizontal translation), in particular the given area being a LiDAR area, the beam of light rays being in the near infrared.
• the operation c) of measuring the optical quality is implemented for a first given zone, for example a camera zone in the visible with the (first) beam (monochromatic, collimated) of light rays in the visible, and repeated for a second given zone, for example a LiDAR zone with the (second) beam (monochromatic, collimated) of light rays in the near infrared, the second given zone preferably being positioned next to the first given zone, in particular the first and second given zones are a camera zone in the visible and a LiDAR zone,
• it is implemented for a duration less than a production line cycle time.

• une carte d’aberration optique,
• une carte de pentes ou de déflection, notamment carte de déflection horizontale ou verticale
• une carte de la fonction d’étalement du point
• une carte de la fonction de transfert de modulation,
• une carte de distorsion verticale et/ou une carte de distorsion horizontale.

The optical defect map is chosen from the following list:

• an optical aberration map,
• a slope or deflection map, including a horizontal or vertical deflection map
• a map of the point spread function
• a map of the modulation transfer function,
• a vertical distortion map and/or a horizontal distortion map.

This optical defect map has the advantage of being obtained in real time. Depending on the embodiment in which the image acquisition device is a LIDAR, the optical defect map may be a horizontal deflection map or a vertical deflection map or both.

• une première carte de défauts optiques parmi les au moins deux cartes de défauts optiques est une carte de distorsion choisie parmi une carte de distorsion verticale et une carte de distorsion horizontale, et
• une deuxième carte de défauts optiques parmi les au moins deux cartes de défauts optiques est une carte de la fonction de transfert de modulation.

According to one embodiment, in particular for a camera zone in the visible, at least two optical defect maps are calculated and:

• a first optical defect map among the at least two optical defect maps is a distortion map selected from a vertical distortion map and a horizontal distortion map, and
• a second optical defect map among the at least two optical defect maps is a modulation transfer function map.

• Génération, à partir du front d'ondes acquis de la zone couverte par l'analyseur de front d'ondes, d'une image d'un interférogramme de la zone du vitrage couverte par l'analyseur de front d'onde, la zone du vitrage couverte par l'analyseur de font d'onde comprenant une pluralité de sous-zones dont la zone donnée ;
• Seuillage de l'image de l'interférogramme pour obtenir une première image. Le seuillage peut être réalisé par exemple par la fonction "Threshold" de la bibliothèque OpenCv ®. La première image est une matrice binaire, ou masque binaire, de même taille que l'image de l'interférogramme ;
• Application d'un filtre morphologique d'ouverture sur la première image pour obtenir une deuxième image, en particulier le filtre morphologique d'ouverture étant obtenu par composition d'un filtre morphologique d'érosion et d'un filtre morphologique de dilatation. Cette étape peut être réalisée, par exemple, par la fonction MorphologyEx Open d’OpenCV®. La deuxième image correspond à l'image de l'interférogramme seuillée filtrée ; et
• Détection, sur la deuxième image, du contour de chaque sous-zone de la zone du vitrage couverte par l'analyseur de front d'onde.

Concerning the step of detecting the given area in an area of the glazing covered by a wavefront analyzer and comprising the given area. May comprise the following sub-steps:

• Generating, from the wavefront acquired from the area covered by the wavefront analyzer, an image of an interferogram of the area of the glazing covered by the wavefront analyzer, the area of the glazing covered by the wavefront analyzer comprising a plurality of sub-areas including the given area;
• Thresholding the interferogram image to obtain a first image. Thresholding can be done for example by the "Threshold" function of the OpenCv ® library. The first image is a binary matrix, or binary mask, of the same size as the interferogram image;
• Applying an aperture morphological filter to the first image to obtain a second image, in particular the aperture morphological filter being obtained by composing an erosion morphological filter and a dilation morphological filter. This step can be performed, for example, by the MorphologyEx Open function of OpenCV®. The second image corresponds to the filtered thresholded interferogram image; and
• Detection, on the second image, of the outline of each sub-zone of the glazing area covered by the wavefront analyzer.

When the number of detected contours is zero, a polygonal shape corresponding to a predefined area is determined on the second image, the polygonal shape representing the given area of the glazing.

When the number of detected contours is non-zero, there are:

- selection of a rectangle of maximum area,

- recovery of the coordinates of the pixels forming the outline included in the rectangle of maximum area,

- from the retrieved pixel coordinates, calculation of a polygonal shape corresponding to an approximation of the outline included in the rectangle of maximum area, the calculated polygonal shape representing the given area of the glazing.

A third aspect of the invention relates to a vehicle glazing production line, comprising a device for holding and moving a glazing unit, characterized in that it comprises a system for automatically measuring the optical quality of a given area of the glazing unit as defined above.

Advantageously, the glazing is positioned inclined on the holding and moving device with an angle of inclination at least equal to an installation angle on the vehicle, with a tolerance of 1° and in particular the glazing is curved and has a convex surface positioned substantially opposite the transmitter or the transmission device. This installation angle can vary, for example, between 20 and 40°.

The cycle time of the production line is preferably less than or equal to 20 seconds, in particular less than or equal to 15 seconds and preferably less than or equal to 12 seconds. This cycle time constraint is linked to the speed of movement of the glazing on the control line (quality) as well as to the production rate which are non-modifiable data, specific to each production line.

The production line or system can know or even store the height offset range between the camera zones of the different models of glazing produced and/or the dimension range (length and height) between the camera zones of the different models of glazing produced and/or the vehicle installation angle of the different models of glazing produced.

By "glazing" is meant a plate formed from a transparent material such as glass or plastic. Advantageously, the glazing may be a windshield, a rear window or even side glazing of a road or rail vehicle. In particular, it is a curved or even laminated glazing comprising two sheets of glass and a polymer lamination interlayer, for example made of polyvinyl butyral (PVB).

The glazing is preferably a road or railway vehicle or even aeronautical glazing and in particular a windshield. The given area is preferably a fraction of the glazing (preferably windshield), preferably curved and on the periphery, an area generally delimited in whole or in part by an opaque area in the visible or even in the infrared. For example, the given area occupies less than 10% of the surface of the glazing. The given area is transparent if the camera area is visible or may be opaque in the visible and transparent in the near infrared if the LiDAR area. The beam (preferably circular and/or collimated) may have a diameter preferably of at most 250mm or 200mm or 150mm and preferably of at least 10 or 20mm or 100mm.

It is possible to successively (during the cycle time) carry out an automatic measurement of a given zone which is a camera zone in the visible and then of another given zone which is a camera zone in the near infrared or so-called LiDAR zone (in particular less than 1000 nm) or vice versa. In this case, a (small) movement of the rail and/or the glazing from one zone to the other (camera zone, LiDAR zone) is provided. The system can comprise both a light beam emitter in the visible and another emitter in the near infrared and a wavefront analyzer sensor in the visible and another sensor in the near infrared or even a common sensor in the visible and in the near infrared.

The system may include a production line stoppage detection module, configured to receive a signal representative of the production line stoppage. The system may include a module for detecting the presence of the glazing between the transmitting and receiving device and the reflecting device or between the transmitting device and the receiving device.

When the production line is stopped, the glazing can be arranged, statically, between the emission and reception device and the reflection device or between the emission device and the reception device. The system of the invention can be integrated so as to be centered horizontally around the given area of the different glazing models (windshields, etc.). The support is therefore centered horizontally within the system regardless of its positioning, based on data from the production line. In other words, when the glazing arrives in the system of the invention, said glazing is positioned so that the beam of light rays is placed along a reference axis of the camera area. This reference axis can be an axis of symmetry of the camera area. The reference axis can also be the axis of symmetry of the glazing or close to the axis of symmetry of the glazing. For a road vehicle windshield, the reference axis is for example close to or in the (current) area of the interior rearview mirror, the rearview mirror can be removed. The camera zone can be close to other sensors (rain sensors, light sensors, etc.).

The glazing (windscreens etc.) can be manufactured model by model, it may be interesting - for reasons of time cost - to carry out the adjustments of the support only once for all the glazing of the same model. In this case, the production line directly sends the information concerning the model of glazing currently being produced to the control unit. The height and angle adjustment of the support is then carried out for the model of glazing currently being produced.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages and characteristics of the invention will appear on reading the description which follows, illustrated by the figures in which:

There schematically represents, in a front view, an example of a windshield with a camera zone;

There schematically represents, in a side view, the measuring system according to a preferred embodiment of the invention;

There schematically represents, in a perspective view, the measuring system of the ;

There represents, in the form of a functional diagram, the different stages of the method of implementing the system of the invention; and

There schematically represents, in a side view, the measuring system according to another embodiment of the invention.

DETAILED DESCRIPTION

An exemplary embodiment of a system for automatically measuring the quality of glazing on a production line is described in detail below, with reference to the attached drawings. This example illustrates the characteristics and advantages of the invention. It is however recalled that the invention is not limited to this example.

In the figures, identical elements are identified by identical references. For reasons of readability of the figures, the size scales between elements represented are not respected.

An example of a glazing whose optical quality of the camera zone is to be measured is shown in the figure . In this example, the glazing 10 comprises a glass sheet 11 and a peripheral opaque element 12a, here a frame. The opaque element 12a makes it possible in particular to hide from the outside of the vehicle elements arranged inside said vehicle, for example a part of an image acquisition device. The opaque element 12a covers at least one of the main faces of the glass sheet 11 so as to border the entire glazing 10. The opaque element 12a can be arranged on the surface of only one of the two main faces of the glass sheet 11 or can comprise several portions, each of the portions being arranged on one and the other of the main faces of the glass sheet 11. Furthermore, the glass sheet 11 can be inclined for example at an angle of 30°. In addition, the glass sheet 11 can be curved along one or two axes, so that a radius of curvature of the sheet 11 is for example between 6 m and 30 m. Preferably, the opaque element 12a is a layer of enamel deposited on the surface of the sheet 11. Naturally, the layer of enamel can be replaced by any other opaque element which makes it possible to hide from the outside certain elements arranged inside the road vehicle.

Preferably the glazing, in particular a windshield, is a laminated glazing (two curved glass sheets bonded by a polymer lamination interlayer), the opaque element 12a can also be formed of several portions, each portion being arranged on the surface of two glass sheets according to the number of portions. For example, the opaque element is a layer (ink, enamel, in particular black, etc.) deposited on the internal face of the outer glass sheet (called face F2) and/or the face called F4 on the passenger compartment side of the inner glass sheet or even a layer (ink, in particular black.) deposited on the lamination interlayer.

Moreover, as can be seen on the , the opaque element 12a delimits a camera zone 12 of the glazing 10, preferably peripheral, located at the upper edge of the glazing 10 here an upper central zone, and in the case of a windshield close to or in the location reserved for the interior rearview mirror, the rearview mirror being able to be removed. The camera zone 12 is intended to be placed on the optical path of an image acquisition device, such as a camera of an intelligent driving assistance system. For example, the surface area of the camera zone 12 is less than 0.5m².

Figures 2 and 3 show two different viewing angles of the measuring system according to the invention. This measuring system 100 comprises a device 120 for emitting and receiving beams of light rays transmitted to, and received from, the camera zone 12 of the glazing 10. The measuring system 100 also comprises a device 130 for reflecting the light rays emitted by the emitting and receiving device 120. The emitting and receiving device 120, the reflection device 130 and the camera zone 12 of the glazing 10 are aligned along an optical axis AA.

The reflection device 130 is a device adapted to reflect the light rays sent by the emission and reflection device 120, along the optical axis AA, via the camera zone 12. According to certain embodiments, the reflection device 130 is a plane mirror, for example of circular shape with a diameter of at least 100 mm. The reflection device 130 is positioned opposite a main face of the glazing 10, for example the rear face of said glazing, that is to say the face intended to be inside the vehicle often called F2 if monolithic glazing or F4 if laminated glazing.

The transmitting and receiving device 120 comprises an emitter 121 configured to emit a beam of light rays through the camera zone 12 of the glazing 10. To do this, the emitter 121 comprises a light source and a collimator placed after the light source, along the optical axis, in order to obtain a beam of light rays that are, for example, parallel. Advantageously, the light source of the emitter 121 is monochromatic and adapted to emit in the visible or near infrared range, i.e. in the wavelengths between 400 nm and 1200 nm, preferably between 620 nm and 950 nm, so that the system of the invention can be used for any camera zone in the visible or near infrared. The light source can be, for example, laser diodes, a white source, a helium-neon source, etc. Advantageously, the size of the beam makes it possible to uniformly cover the entire camera zone 12 of the glazing 10 while guaranteeing sufficient resolution and a flow making it possible to obtain information in the entire camera zone 12. The beam of light rays covers at least the transparent surface of the camera zone but it can cover a wider area than the camera zone 12, which is the area intended to be coupled to the vehicle camera, the coupling generally being only on a region of this area. For example, the camera zone 12, in particular in the visible, has a width (lower base for example if trapezoidal) of at least 20 mm, 30 mm or 50 mm and at most 150 mm or 100 mm; it is preferably trapezoidal (upper base of width less than the lower base) and the height is at least 8 mm, 10 mm or even 15 mm and at most 60 mm or 55 mm or 30 mm or 25 mm.

The beam of light rays has, for example, a diameter greater than or equal to the maximum width of the camera area, preferably at least 100mm.

In particular in the case of a LiDAR zone, the camera zone 12 has a width (lower base for example if trapezoidal) of at least 150 mm or 200 or 250 mm and at most 600 mm. It is preferably trapezoidal (upper base of width less than the lower base) and the height is at least 100 mm or 150 mm and at most 400 mm or 300 mm or 250 mm. Thus, the beam of light rays has, for example, a diameter greater than or equal to a portion of the LiDAR zone, for example half the width of the LiDAR zone.

A laminated glazing, such as a road vehicle windshield, may have a tinted inner sheet with a through hole in the LiDAR zone for increased transparency at the LiDAR working wavelength. An example of a LiDAR zone is described in application WO2021053138.

In the case of a LiDAR zone, when the beam of light rays has a width less than the width of said LiDAR zone, it is considered that the LiDAR zone is formed of two (or three or more) partial camera zones, with an overlap, for example by a horizontal offset (preferably by moving the glazing).

The wavefront measurement is then the same for the LiDAR zone as for a camera zone even when the size of the LiDAR zone is two (or three or more) times larger than the camera zone in the visible. In the case of a large LiDAR zone (i.e. of a width greater than the width of the beam of light rays), the wavefront measurement is then carried out in two (or three or more) partial measurements, by shifting the LiDAR zone between each partial measurement, i.e. by shifting the glazing (windshield, etc.) so that the reflection device 130 and the emission and reflection device 120 are aligned along the optical axis AA, via the partial camera zone considered. The number of partial camera zones is limited only to the cycle time allocated to measuring the optical quality of the given area of the glazing, the measurement time of a camera zone (and therefore of a partial camera zone) being, thanks to the invention, significantly less than the cycle time (of the order of 1/3 or even 1/6th of the cycle time).

The LiDAR area can be opaque in the visible, in particular by means of a black camouflage element (and transparent at the working wavelength of the LiDAR). The analysis area is therefore not necessarily transparent.

The beam of light rays in the visible range is chosen, in particular, so as to cover all of the camera zones in the visible range of all of the glazing models (of the production line). A beam of light rays in the near infrared range is chosen, in particular, so as to cover all of the partial zones (of predefined size) forming the LiDAR zone when the latter is of large dimensions. The beam therefore covers the camera zone 12 of the glazing model having the largest camera zone in the visible range or the partial zone of the largest LiDAR zone. The beam has, for example, a diameter of 130 mm and is adjusted so as to be centered on the center of gravity of the camera. Thus, the measuring system is suitable for all of the glazing models moving along the production line. In the context of stereovision, i.e. with two camera zones in the visible range (each provided for one camera), the beam of light rays can make it possible to measure both camera zones in one go.

The transmitting and receiving device 120 also comprises a wavefront analyzer 122, also called an abberometer, designed to measure the shape of the wavefront of the rays emitted by the emitter 121 and reflected by the reflection device 130 and to determine the deformation undergone by the wavefront during its passage through the camera zone 12. It is recalled that a wavefront is the shape of the surface of a light wave at a given location, the light ray being an imaginary straight line perpendicular to said wavefront. The wavefront analyzer 122 measures the shape of this wave surface. To do this, the wavefront analyzer (more simply called analyzer) breaks down the wavefront into elementary wavefronts and determines, for each elementary wavefront, its orientation; the measurement of these orientations makes it possible, after integration, to go back to the shape of the wavefront. An example of a wavefront analyzer that can be implemented in the system according to the invention is described in detail in patent document WO 2021/110901 A1.

The transmitting and receiving device 120, the reflecting device 130 and the camera zone 12 are aligned along the optical axis AA. This optical axis AA forms with the glazing 10 an angle α corresponding to the installation angle on the vehicle. This installation angle can vary, for example, between 20 and 40°. Thus, the measurement of the optical quality of the camera zone 12 is carried out for the angle of inclination at which the glazing will be installed in the vehicle. The measurement obtained therefore corresponds to the actual quality of the glazing in place on the vehicle.

To ensure alignment of the transmitting and receiving device 120 and the reflection device 130 via the camera zone 12, said transmitting and receiving device 120 and the reflection device 130 are mounted on the same support 110. The transmitting and receiving device 120 and the reflection device 130 are thus integral with each other so that any vibrations of the production line have no effect on the measurements carried out with the wavefront analyzer. They are mounted, in particular, each at one end of the support 110, each of the ends of the support facing one of the faces of the glazing 10. In the example of FIGS. 2 and 3, the support 110 has a substantially arched shape, that is to say a curved shape having substantially the appearance of an arc. The section of this arch shape is rounded with, for example, a U or C shape. In the preferred embodiment of Figures 2 and 3, the arch-shaped support 110 has a substantially semi-cylindrical, C-shaped section. In another embodiment (not shown), the support 110 is circular and hollowed out in its center so that it surrounds the rail 200 and the glazing holding device 210.

The support 110 (also called a hoop support or simply a support) comprises a first zone 111 and a second zone 112 diametrically opposed. These first and second zones 111, 112 can be the ends of the support 110 when the latter is an open structure as shown in FIGS. 2 and 3. The transmission and reception device 120 is mounted on the first zone 111; the reflection device 130 is mounted on the second zone 112. The zones 111 and 112 can be curved, like the end 111, or flattened, like the end 112 of the The shape of the end is adapted to the device it supports, in order to facilitate the mounting of said device.

In a preferred embodiment, the first zone 111 on which the transmission and reception device 120 is mounted is positioned in the vicinity of the control unit 150 described below. The second zone 112- on which the reflection device 130 is mounted is then positioned at a distance from the control unit 150. Indeed, the transmission and reception device being relatively heavy, compared to the reflection device, it is advantageous for it to be positioned as close to the ground as possible to avoid the risks of misalignment of the optics housed in said device.

The term "in the vicinity" means that the transmitting and receiving device is relatively close to the control unit compared to the reflecting device which is further away.

This preferred embodiment in which the transmitting and receiving device 120 is positioned “downwards” (i.e. in the vicinity of the control unit 150) and the reflection device is positioned “upwards” (i.e. at a distance from the control unit 150) also makes it possible to avoid dust during measurements.

In some embodiments, the support 110 is made of a black and matte material or covered with a black and matte layer (paint). This black and matte color makes it possible to avoid any parasitic reflection during measurements.

According to some embodiments, the arch-shaped support 110 comprises a single branch of a width adapted to the size of the transmission and reception device and/or the reflection device. According to other embodiments, such as that of the , the support 110 comprises two branches 113, 114, substantially parallel to each other and between which are mounted the transmission and reception device 120 and the reflection device 130. A base can be fixed between the two branches 113, 114, at one or both ends 111, 112 of the support, to facilitate the installation of the devices 120 and 130. The embodiment with double branches 113, 140 offers a weight saving, not insignificant for the mechanical movement of the support, as explained later. Whatever the embodiment, the support can be made of metal or, in the absence of a hot zone in the vicinity, in rigid rubber or in any other material sufficiently robust to support the weight of the transmission and reception device 120 (for example of the order of 25 kg) without untimely movement.

The fact that the transmitting and receiving device 120 and the reflecting device 130 are mounted on the two opposite ends of the same support 110 makes it possible to ensure alignment of the two devices in all circumstances, which offers an appreciable time saving for a measurement whose duration is limited by the production line itself. Indeed, a duration of the order of 12 to 16 seconds inside the measuring system 100 is allocated, by the production line, for measuring the optical quality of the camera zone of a glazing, this duration being determined according to the speed of movement of the glazings on the production line and the number of glazings to be manufactured per day.

The fact that the transmitting and receiving device 120 and the reflecting device 130 are mounted on two opposite zones of the same support 110 makes the two devices integral with each other. This interlocking allows simultaneous movement of the two devices 120, 130; it also makes it possible to avoid vibrations likely to distort the measurements. Indeed, under the effect of the movements, and/or other external events, the support 110 is likely to vibrate; as the vibrations are similar for the two devices 120 and 130, this has the effect of canceling them out so that said vibrations do not cause any impact on the measurements.

As shown in FIGS. 2 and 3, the support 110 is mounted on a frame 140 controlled by a control unit 150. The frame 140 is an assembly of parts fixed to each other so as to be able to cause a movement of the support 110. The frame 140 may comprise, for example, a translation table 144 mounted on jacks 143 allowing a vertical translational movement of said translation table. The frame 140 may also comprise a first and a second rotation arm, respectively 141, 142, fixed on the one hand on the support 110 and on the other hand on the table 144. These rotation arms 141, 142 are mounted so as to be movable in translation relative to the table 144 and are fixed on the support 110 at a distance from each other. Thus mounted, the rotation arms 141, 142 make it possible to transform a translational movement into an angular movement of the support 110. Indeed, each of the rotation arms 141, 142 is movable in translation, independently of one another and each of the rotation arms is fixed to the support 100 at an angular location of the arch different from one another. For example, the rotation arm 141 can be fixed near the zone 111 of the support 110 and the rotation arm 142 can be fixed approximately at the center of the arch 110. Thus, each different vertical movement of the rotation arms 141, 142 results in a different angular movement of the support 110. Advantageously, the rotation arms 141, 142 each have an angled shape making it possible to improve the precision of the rotational movement of the support 110.

The frame 140 thus allows a translational movement of the support 110 in a vertical direction Y and a rotational movement in the direction R. The translational movement makes it possible to adapt the position of the devices 120 and 130 according to the dimension of the glazing model 10 of which the optical quality of the camera zone is measured. According to current glazing models, the vertical translation is included in an interval, for example, from 0 to 25 cm. The rotational movement, or angular movement, makes it possible to adapt the position of the devices 120 and 130 according to the installation angle of the glazing 10. According to current glazing models, the angular movement is included, for example, between 20 and 40°. It should be noted, however, that these examples of movements depend heavily on the glazing models and that they can, of course, evolve according to the evolution of the glazing and the camera zones of the glazing.

The coupling of the translational and rotational movement allows an optimal alignment of the emission and reception device 120 and of the reflection device 130, with the camera zone 12 of the glazing 10 whatever the model of the glazing 10. The control unit 150 comprises electronic and/or computer means for controlling the translational and rotational movements of the frame 140 and, consequently, the translational and rotational movements of the support 110. This control unit 150 can be controlled by an operator who enters, for example via a keyboard, the number of the glazing model to be measured; alternatively the control unit 150 can be connected to a general control device of the production line or to the control unit of the previous block in the production line which automatically transmits the number of the glazing model to be measured.

The examples in Figures 2 and 3 show a device for holding and moving the glazing on the production line. They show in particular a rail 200 for moving the glazing 10 ensuring the movement of each glazing from one block to the next block on the production line. The also shows a holding element 210, in connection with the rail 200, and making it possible to hold the glazing on the rail 200, inside the measuring system 100. Alternatively, the holding of the glazing 10 on the rail 200 inside the measuring system 100 can be ensured by a robot arm 220, as shown in the .

The support 110 as just described is designed to extend at least partially around the rail 200 and/or the holding element 210 of the glazing 10 so as to extend from one face of the glazing 10 to the other face of the glazing. Thus, the emission and reception device 120 is positioned opposite one of the faces of the glazing, for example the front face 10a, and the reflection device 130 is positioned opposite the other face of the glazing, for example the rear face 10b of the glazing (the front face being the face of the glazing intended to be outside the vehicle often called F1 and the rear face being the face intended to be inside the vehicle often called F2 if monolithic glazing or F4 if laminated glazing).

The glazings 10 are positioned inclined on the production line. They are, for example, positioned at an angle of inclination of approximately 10 to 15° relative to the vertical Y, i.e. relative to the normal to the ground, to which is added the inclination corresponding to the angle α of installation on the vehicle, with a tolerance of ±1°. Thus, for example, for an angle α of approximately 30°, the glazing 10 is inclined by approximately 45° relative to the vertical, on the rail 200. To avoid any risk of contact between the measuring system of the invention and the glazing 10, while taking this inclination into account, the support 110 has suitable dimensions. A support 110, of rounded shape, may, for example, have a diameter greater than 1500 mm. In particular, the distance between the transmitting and receiving device 120 and the reflecting device 130 may be 1500 mm with a distance between the transmitting and receiving device and the camera area of approximately 900 mm and a distance between the camera area and the reflecting device of approximately 600 mm. The frame may have a diameter of the order of 2500 mm. Such dimensions also make it possible to take into account the fact that the surface of the glazing is curved and that it is necessary for the system not to touch the glazing. The C-shape, described above, of the support 110 also contributes to avoiding any risk of contact between the system and the glazing, by reducing the dimensions of the system as much as possible.

The glazings 10 are for example positioned on the production line so that the convex surface of said curved glazings is opposite the transmission and reception device 120, that is to say with the concave face substantially facing the ground. This positioning makes it possible to reproduce as best as possible the relative positioning between the glazing and the camera, when the glazing is mounted on a vehicle.

Another embodiment of the system according to the invention is shown in the . This embodiment differs from the previous one in that a transmission device 160 is positioned on the first area 111 of the support and a wavefront analyzer 170 is positioned on the second area 112 of said support. In this embodiment, there is no reflection device; the analyzer 170 directly receives the beam of light rays sent by the transmission device. Except for this difference, all the variants, explanations and advantages given previously remain valid, the reflection device 130 having to be replaced by the analyzer 170 and the transmission and reception device 120 by the transmission device 160 in the preceding description.

• a) positionnement en translation verticale 330 du système 100 et, en particulier, du support 110 sur lequel sont montés, à distance l’un de l’autre, soit le dispositif d'émission et de réception 120 et le dispositif de réflexion 130, soit le dispositif (160) d’émission et le dispositif (170) de réception,
• b) positionnement angulaire 340 du système 100, le positionnement translatif et/ou le positionnement angulaire étant définis de sorte que, d’une part, le dispositif d’émission et de réception 120 et le dispositif de réflexion 130 dans un mode de réalisation) ou le dispositif 160 d’émission et le dispositif 170 de réception (dans l’autre mode de réalisation) soient alignés suivant le même axe optique AA et, d’autre part, que la zone donnée 12 soit couverte par le faisceau de rayons lumineux émis par le dispositif d’émission et de réception 120 ou le dispositif d’émission 160, et
• c) mesure 350 de la qualité optique de la zone donnée 12.

The measurement system 100 described above can be implemented by the method 300 shown in the . This process involves the following operations (a) and b) (in any order):

• a) positioning in vertical translation 330 of the system 100 and, in particular, of the support 110 on which are mounted, at a distance from each other, either the transmission and reception device 120 and the reflection device 130, or the transmission device (160) and the reception device (170),
• b) angular positioning 340 of the system 100, the translational positioning and/or the angular positioning being defined so that, on the one hand, the emission and reception device 120 and the reflection device 130 in one embodiment) or the emission device 160 and the reception device 170 (in the other embodiment) are aligned along the same optical axis AA and, on the other hand, that the given area 12 is covered by the beam of light rays emitted by the emission and reception device 120 or the emission device 160, and
• c) measure 350 of the optical quality of the given area 12.

More precisely, this method 300 comprises a first operation 320 of detecting the presence of the glazing and identifying the model of glazing to be measured. Indeed, since the glazings (windshields, etc.) are manufactured model by model, it may be interesting – for reasons of time cost – to carry out the adjustments of the support 110 only once for all the glazings of the same model. In this case, the production line directly sends the information concerning the model of glazing currently being produced to the control unit 150. The height and angle adjustment of the support 110 is then carried out for the model of glazing currently being produced.

In an alternative, the operation 310 of stopping the glazing in the block can be carried out before the operation 320 of identifying the glazing model, this alternative however resulting in a longer measurement duration than in the embodiment of the .

Depending on the glazing model, the positioning of the support 110 is controlled and the frame 140 is moved accordingly. The vertical translational positioning of the support 110 (operation 330) can be carried out first, then its angular positioning (operation 340). Alternatively, the angular positioning of the support 110 can be carried out before the vertical translational positioning, more simply called translational positioning. When the translational and rotational positionings of the support 100 are completed, the method comprises a step 310 of stopping the glazing 10 in the measuring system 100. It then comprises an operation 350 of measuring the optical quality of the camera zone of the glazing 10 by the wavefront analysis method. The measurement itself is very fast (of the order of a 100th of a millisecond); most of the allocated time, for example 14 seconds, is used for the mechanical positioning of the support 110.

• Génération, à partir du front d'ondes acquis de la zone couverte par l'analyseur de front d'ondes, d'une image d'un interférogramme de la zone du vitrage couverte par l'analyseur de front d'onde, la zone du vitrage couverte par l'analyseur de font d'onde comprenant une pluralité de sous-zones dont la zone donnée ;
• Seuillage de l'image de l'interférogramme pour obtenir une première image. Le seuillage peut être réalisé par exemple par la fonction "Threshold" de la bibliothèque OpenCv ®. La première image est une matrice binaire, ou masque binaire, de même taille que l'image de l'interférogramme ;
• Application d'un filtre morphologique d'ouverture sur la première image pour obtenir une deuxième image, en particulier le filtre morphologique d'ouverture étant obtenu par composition d'un filtre morphologique d'érosion et d'un filtre morphologique de dilatation. Cette étape peut être réalisée, par exemple, par la fonction MorphologyEx Open d’OpenCV®. La deuxième image correspond à l'image de l'interférogramme seuillée filtrée ; et
• Détection, sur la deuxième image, du contour de chaque sous-zone de la zone du vitrage couverte par l'analyseur de front d'onde.

The optical quality measurement operation 350 comprises a step of detecting the given area 12 in a zone of the glazing covered by a wavefront analyzer and comprising the given area. This step comprises the following sub-steps:

• Generating, from the wavefront acquired from the area covered by the wavefront analyzer, an image of an interferogram of the area of the glazing covered by the wavefront analyzer, the area of the glazing covered by the wavefront analyzer comprising a plurality of sub-areas including the given area;
• Thresholding the interferogram image to obtain a first image. Thresholding can be done for example by the "Threshold" function of the OpenCv ® library. The first image is a binary matrix, or binary mask, of the same size as the interferogram image;
• Applying an aperture morphological filter to the first image to obtain a second image, in particular the aperture morphological filter being obtained by composing an erosion morphological filter and a dilation morphological filter. This step can be performed, for example, by the MorphologyEx Open function of OpenCV®. The second image corresponds to the filtered thresholded interferogram image; and
• Detection, on the second image, of the outline of each sub-zone of the glazing area covered by the wavefront analyzer.

When the number of detected contours is zero, a polygonal shape corresponding to a predefined area is determined on the second image, the polygonal shape representing the given area of the glazing.

When the number of detected contours is non-zero, there are:

- selection of a rectangle of maximum area,

- recovery of the coordinates of the pixels forming the outline included in the rectangle of maximum area,

- from the retrieved pixel coordinates, calculation of a polygonal shape corresponding to an approximation of the outline included in the rectangle of maximum area, the calculated polygonal shape representing the given area of the glazing.

The operation 350 of measuring the optical quality also includes a step of analysis, by the wavefront analyzer, of the wavefront of the light rays transmitted by the camera zone with the generation of a wavefront error map. From this wavefront error map, at least one map of the optical defects present in the camera zone of the glazing is determined in real time.

The method of the invention further comprises, between the step of detecting the presence of the glazing and the detection of the given zone, a step of acquiring the wavefront of the zone of the glazing covered by the wavefront analyzer.

It will be understood from the above that the method preferably does not include a step of positioning the support in horizontal translation, i.e. in the main direction of movement of the line. Indeed, the system of the invention can be integrated so as to be centered horizontally around the given area of the different windshield models. The support 110 is therefore centered horizontally within the system regardless of its positioning, based on data from the production line. In other words, when the glazing 10 arrives in the system of the invention, said glazing is positioned so that the beam of light rays is placed along a reference axis CC of the camera zone 12. This reference axis CC can be an axis of symmetry of the camera zone 12, as shown in FIG. , or a partial camera area in the case of a large LiDAR area. The CC reference axis may, alternatively, be a predefined axis corresponding to the axis of emission of the beam of light rays and known to the production line, in particular when the camera area is not centered on the glazing. This CC axis constitutes a reference for positioning the glazing in the production line. It should be noted that this CC reference axis may, in certain cases, coincide with the axis of symmetry of the glazing with a possible offset of a few centimeters in the rearview mirror area, for example 5 cm maximum.

In a preferred embodiment of the invention (in the case of a measurement of a single zone), the method of the invention provides for a stop of the glazing defined as a function of this reference axis CC, that is to say so that the beam of light rays is aligned with the reference axis CC. Thus, no horizontal translation of the support 110 is necessary, the horizontal centering of the support 110 being in fact obtained as soon as the glazing stops. The means for translational movement of the support 110 therefore only integrate means for vertically adjusting the position of the glazing. Alternatively, in the case where two given areas, for example adjacent, are measured, either preferably the glazing itself is moved by the production line after the measurement of the first given area to measure the second given area, or a horizontal translation of the support 110 is provided, after the measurement of the first given area, so that the emission and reception device and the reflection device (or the emission device and the reception device) are aligned with the second given area.

In another embodiment, the means for translational movement of the support 110 integrate both means for vertically adjusting the position of the glazing and means for horizontally adjusting the positioning of said glazing in the optical quality measurement block. This embodiment can be implemented in particular in the context of stereovision, with two camera zones in the visible offset from each other.

The results of the measurements of operation 350 can then be recorded (operation 360). The measurements are preferably recorded in real time in a file specific to each glazing. Thus, at the end of the production line, it is possible to know the optical quality of the camera zone of each of the glazings produced on this production line.

Of course, each glazing moving along the production line is treated in the same way. After detecting the arrival of a new glazing (operation 370), operation 310 and the following operations 350 and 360 are repeated for the new glazing up to the last glazing on the production line.

As explained above, the translational adjustment and the angular adjustment of the support 110 is carried out once for each windshield model. The measurement of the camera area and the calculations of the different metrics indicating its quality level are carried out in a predefined cycle time, preferably at most 20 seconds, for example 12 seconds.

Although described through a number of examples, variants and embodiments, the measurement system according to the invention, and its method of implementation, include various variants, modifications and improvements which will be obvious to those skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention.

Claims (25)

System (100) for automatically measuring the optical quality of a given area (12) of a vehicle window (140), comprising:

• a device (120) for emitting and receiving a beam of light rays defined to cover the given area, the emitting and receiving device being positioned opposite a first main face (10a) of the glazing and configured to emit the beam of light rays towards the given area (12) and to receive said beam of light rays transmitted by this given area, said emitting and receiving device comprising a light ray beam emitter (121) and a wavefront analyzer (122) configured to analyze the wavefront of the light rays transmitted by the given area (12),
• a device (130) for reflecting light rays, positioned opposite a second main face (10b) of the glazing and configured to return the beam of light rays towards the emission and reception device (120), the emission and reception device (120) and the reflection device (130) being aligned along an optical axis (AA),
• a support (110), movable, extending at least from the first main face (10a) of the glazing (10) to the second main face (10b) of the glazing and on which the emission and reception device (120) and the reflection device (130) are mounted, said reflection device thus being integral with the emission and reception device, and
• a support movement control unit (150), configured to control simultaneous movements of the transmitting and receiving device (120) and the reflecting device (130) relative to the given area of the glazing.

System according to claim 1, characterized in that the support is an open structure comprising a first zone (111) on which the transmission and reception device (120) is mounted and a second zone (112) on which the reflection device (130) is mounted, said first and second zones being diametrically opposed. System (100) for automatically measuring the optical quality of a given area (12) of a vehicle window (140), comprising:

• a device (160) for emitting a beam of light rays defined to cover the given area, the emitting device being positioned opposite a first main face (10a) of the glazing and configured to emit the beam of light rays towards the given area (12),
• a device (170) for receiving light rays, positioned opposite a second main face (10b) of the glazing and comprising a wavefront analyzer configured to receive the beam of light rays transmitted by the given zone (12) and analyze the wavefront of said light rays, the receiving device (170) and the emitting device (160) being aligned along an optical axis (AA),
• a support (110), movable, extending at least from the first main face (10a) of the glazing (10) to the second main face (10b) of the glazing and on which the emission device and the reception device are mounted, said reception device thus being integral with the emission device, and
• a support movement control unit (150), configured to control simultaneous movements of the transmitting device (160) and the receiving device (170) relative to the given area of the glazing.

System according to claim 3, characterized in that the support is an open structure comprising a first zone (111) on which the transmission device (160) is mounted and a second zone (112) on which the reception device (170) is mounted, said first and second zones being diametrically opposed. System according to any one of claims 1 to 4, characterized in that the movement control unit (150) comprises means for translational movement of the support (110) and/or means for angular movement of said support. System according to any one of claims 1 to 5, characterized in that the support (110) has a curved shape extending at least from the first main face (10a) of the glazing (10) to the second main face (10b) of the glazing, at a distance from the movement control unit (150). System according to claim 6, characterized in that the support has a C shape. System according to any one of the preceding claims, characterized in that the support (110) comprises two branches (113, 114) in planes substantially parallel to each other, between which are fixed, to each of the first and second zones (111, 112), a base configured to support, respectively, the transmission and reception device (120) and the reflection device (130) or to support, respectively the transmission device (160) and the reception device (170). System according to any one of claims 6 to 8, characterized in that the support (110) is mounted on a frame (140) controlled by the control unit (150) and configured to move the support (110) in translation in a vertical direction (Y) and/or in rotation in an angular direction (R). System according to claim 9, characterized in that the frame (140) comprises a vertical translation table (144) mounted on jacks (143) and first and second rotation arms (141, 142) fixed on the one hand to the support (110) and on the other hand to the vertical translation table (144). System according to any one of claims 2, 4 or 5 to 10, characterized in that the first zone (111) of the support (110) is positioned close to the control unit (150), the second zone (112) of the support (110) being positioned at a distance from said control unit. System according to any one of claims 1 to 11, characterized in that it extends at least partially around a device for holding and moving the glazing (200-220) of a glazing production line. System according to claim 12, in which the device for holding and moving the glazing comprises at least one rail (200) for moving said glazing, characterized in that the support (110) extends at least partially around the moving rail. System according to any one of claims 1 to 2 and 5 to 13, characterized in that the reflection device (130) comprises a plane mirror. System according to any one of the preceding claims, characterized in that the emission device (160) or the emission or reception device (120) is configured to emit a beam of light rays in the visible and/or a beam of light rays in the near infrared. Method (300) for automatically measuring the optical quality of a given area (12) of a vehicle glazing (10) in a glazing production line, in particular implemented in the measuring system according to one of claims 1 to 15, which comprises the following operations:

1. positioning in vertical translation (330) of a system (100) for automatically measuring the optical quality of the given area of the glazing, said system comprising a support (110) on which are mounted, at a distance from each other, either an emission and reception device (120) defined to cover the given area, comprising an emitter (121) of a beam of light rays and a wave front analyzer (122), and a reflection device (130) or a device (160) for emitting a beam of light rays defined to cover the given area and a device (170) for receiving the light rays comprising a wave front analyzer,
2. angular positioning (340) of the system (100) for automatically measuring the optical quality of the given area of the glazing, the translational positioning and/or the angular positioning being defined so that, on the one hand, the emission and reception device (120) and the reflection device (130) or the emission device (160) and the reception device (170) are aligned along the same optical axis (AA) and, on the other hand, that the given area (12) is covered by a beam of light rays emitted by the emission and reception device (120) or the emission device (160), operations a) and b) being in any order
3. measurement (350) of the optical quality of the given area (12).

Method according to claim 16, characterized in that the operation c) of measuring (350) the optical quality of the given zone is carried out for glazing positioned at an installation angle on the vehicle (α). Method according to claim 16 or 17, characterized in that it comprises, after operation c), an operation (360) of recording in real time the measured optical quality data. Method according to any one of claims 16 to 18, characterized in that operation c) of measuring the optical quality comprises a step of detecting the given zone (12) of the glazing in a zone of the glazing covered by the wavefront analyzer and comprising said given zone. Method according to any one of claims 16 to 19, characterized in that the operation c) of measuring (350) the optical quality of the given zone comprises:

• a step of emitting, by the emitting and receiving device (120) or the emitting device (160), a beam of light rays towards the given area, and
• a step of analysis, by the wavefront analyzer, of the wavefront of the light rays transmitted by the given zone with the generation of a wavefront error map and, from said wavefront error map, a determination of at least one map of the optical defects present in the given zone of the glazing.

Method according to any one of claims 16 to 20, characterized in that the given zone comprises at least two partial zones positioned side by side, the optical quality of each partial zone being measured successively by the system according to any one of claims 1 to 15, preferably after movement of the glazing on the production line, in particular the given zone being a LiDAR zone, the beam being in the near infrared. Method according to any one of claims 16 to 20, characterized in that the operation c) of measuring the optical quality is implemented for a first given zone (12) and repeated for a second given zone, the second given zone preferably being positioned next to the first given zone, in particular the first and second given zones are a camera zone in the visible, the beam of light rays being in the visible, and a LiDAR zone, the beam of light rays being in the near infrared. Method according to any one of claims 16 to 22, characterized in that it is implemented for a duration less than a cycle time of the production line. Vehicle glazing production line, comprising a device for holding and moving a glazing unit, characterized in that it comprises a system (100) for automatically measuring the optical quality of a given area of the glazing unit according to any one of claims 1 to 15. Production line according to claim 24, characterized in that the glazing (10) is positioned inclined on the holding and moving device with an angle of inclination at least equal to an installation angle (α) on the vehicle, with a tolerance of 1°, and in particular the glazing is curved and has a convex surface positioned substantially opposite the transmitter or the transmission device.