Devices and methods for inspecting surfaces by recording high-resolution images.

Abstract

An apparatus (1) for inspecting the optical properties of a surface (10) having an effect pigment, the apparatus having a first radiating device (2) and a first image recording device (6), the first radiating device being adapted and intended to irradiate radiation onto the surface (10) to be inspected along a first irradiation direction (R1), the first irradiation direction being characterized by a first irradiation angle (a1), and the first image recording device being adapted to record a spatially resolved image of the surface irradiated by the first irradiating device; the apparatus (1) having a second image recording device (8) and an evaluation device, the second image recording device being adapted to record a spatially resolved image of the surface (10) irradiated by the first radiating device (2), and the evaluation device being adapted and intended to evaluate the image recorded by the second image recording device (8) to determine at least one property representing the characteristics of the effect pigment and / or a single effect pigment.

Description

Technical Field

[0001] This invention relates to apparatus and methods for inspecting surface properties. The invention is described with reference to the surface of motor vehicles, but it should be noted that the invention is also applicable to other surfaces, such as furniture surfaces. Background Technology

[0002] So-called multi-angle measuring devices are already known in the prior art. In such devices, radiation, especially visible light, is irradiated onto the surface to be inspected from different directions, and the radiation scattered and / or reflected by the surface is analyzed, and / or an image of the irradiated or illuminated surface is recorded.

[0003] For this purpose, it is known that several radiating devices are provided in a housing, which irradiate the surface from different angles, particularly with light. Furthermore, an image camera is often provided to record images of the surface irradiated by the various radiating devices.

[0004] So-called effect pigment coatings have been known in the prior art for some time. These effect pigment coatings contain effect pigments within or in the actual coating layer, which in turn alters the optical appearance of the surface. Such effect pigment layers are sometimes more difficult to optically detect than conventional surfaces, and are particularly more difficult to classify. Furthermore, the visual appearance of such effect pigment layers varies significantly depending on the direction of illumination and the direction of observation.

[0005] For this reason, various methods and apparatuses have been described that enable a more objective evaluation of these effects on pigment surfaces.

[0006] However, it is desirable to characterize these surfaces more precisely.

[0007] Therefore, the present invention is based on the aim of improving the evaluation of such surfaces and also enabling more precise inspection of these surfaces. According to the invention, this is achieved through the objectives of the independent patent claims. Advantageous embodiments and further developments are the subject of the dependent claims. Summary of the Invention

[0008] The apparatus according to the invention for inspecting the optical properties of surfaces, particularly surfaces containing effect pigments, has a first radiating device adapted and intended to irradiate radiation (and particularly light, and especially light in the visible wavelength range) onto the surface to be inspected along a first irradiation direction characterized by a first irradiation angle. Furthermore, a second radiating device is provided, adapted and intended to irradiate radiation (and particularly light, and especially light in the visible wavelength range) onto the surface to be inspected along a second irradiation direction characterized by a second irradiation angle.

[0009] In addition, a first image recording device is provided, which is adapted and intended to record a spatially resolved image of a surface irradiated and / or illuminated by at least one of the irradiation directions.

[0010] According to the invention, the device has a second image recording device adapted and intended to record spatially resolved images of a surface (in particular, additionally), and especially to record spatially resolved images of a surface irradiated and / or irradiated by at least one of the irradiation devices (in particular, additionally).

[0011] Therefore, an apparatus using (at least) two image recording devices is proposed, wherein these image recording devices preferably have different resolutions and / or are capable of recording images of the surface at different resolutions (and / or different magnifications of the recorded images relative to the surface).

[0012] An additional apparatus according to the invention for inspecting the optical properties of a surface having an effect pigment has a first radiating device adapted and intended to irradiate radiation (and in particular light, and especially light in the visible wavelength range) onto the surface to be inspected along a first irradiation direction characterized by a first irradiation angle.

[0013] Furthermore, a second irradiation device is preferably provided, which is adapted and intended to irradiate radiation (and in particular light, and especially light in the visible wavelength range) onto the surface to be inspected along a second irradiation direction, characterized by a second irradiation angle.

[0014] In addition, a first image recording device is provided, which is adapted and intended to record spatially resolved images of a surface, and particularly to record spatially resolved images of a surface irradiated by an irradiation device.

[0015] According to the invention, the device has a second image recording device and an evaluation device, the second image recording device being adapted and intended to record a spatially resolved image of a surface, and particularly to record a spatially resolved image of a surface irradiated by (at least one) irradiation device, and the evaluation device being adapted and intended to evaluate the image recorded by the second image recording device to determine at least one property representing the characteristics of effect pigments and / or individual effect pigments.

[0016] Therefore, two methods were proposed to observe the surface using two image recording devices. In the second case, properties, particularly those of the effect pigments, were determined based on the images (or multiple images).

[0017] In another preferred embodiment, the surface has so-called effect pigments, as mentioned above. Within the scope of the invention, it is therefore proposed that the recorded images are (high) resolution, such that the effect pigments can be observed at least in groups and preferably individually.

[0018] In a preferred embodiment, the first image recording device and the second image recording device are arranged such that the first image recording device and the second image recording device observe the same area of ​​the illuminated surface or record an image of the same area.

[0019] However, it is also conceivable that the second image recording device records images of surface regions different from those of the first image recording device, and particularly records images of regions laterally offset from the region recorded by the first image recording device. The displacement is preferably less than 10 cm, preferably less than 8 cm, preferably less than 6 cm, and particularly preferably less than 5 cm. The displacement is preferably greater than 0.5 cm, preferably greater than 1.0 cm, and particularly preferably greater than 2.0 cm.

[0020] Preferably, the second image recording device has an autofocus unit and / or is designed as an autofocus camera module. This is likely to be the case regardless of where the second image recording device is located.

[0021] The first image recording device may also have an autofocus unit.

[0022] In another preferred embodiment, the second image recording device has an additional illumination device that illuminates a surface area from which the second image recording device records an image. This can particularly be ring illumination.

[0023] In this configuration, the second image recording device is preferably designed as a separate unit. On one hand, this means that the first and second image recording devices record different areas of the surface. However, on the other hand, this also means that a beam splitter unit, which is provided when the same segments of the surface will be recorded and / or recorded at the same angle, can be omitted.

[0024] In another preferred embodiment, the device has an additional detection device adapted and designed to detect radiation emitted by the radiating device and reflected by the surface. This could be a detection device adapted and designed to detect the intensity and / or wavelength of the radiation reflected by the surface.

[0025] In another preferred embodiment, the device has an additional detection device adapted and designed to detect the intensity of radiation scattered by the surface.

[0026] In another preferred embodiment, the first radiating device, and preferably at least one radiating device, is adapted and intended to emit radiation in different colors. For example, an LED capable of emitting light of different wavelengths can be used. However, it is also conceivable to use a filter arranged in the beam path between a light source, such as a white light source (e.g., one or more LEDs), and the surface to be inspected. In this way, the control device can control the irradiation of the surface in different colors, and particularly in the visible wavelength range.

[0027] In another preferred embodiment, the first radiating device has a light source and a plurality of color filter devices that can be selectively moved into the beam path between the light source and the surface to be inspected. Particularly preferably, the radiating device has a filter wheel that can rotate about a predetermined axis of rotation, and the color filter devices are arranged on the filter wheel.

[0028] However, it is also conceivable to move such filter elements into the beam path between the surface and at least one detection device and / or image recording device.

[0029] In another advantageous embodiment, the device has a second radiation detection device adapted and designed to detect radiation emitted, and in particular scattered, from the surface to be inspected at a second emission angle in response to irradiation.

[0030] Particularly preferably, the device has an additional radiation detection device adapted and designed to record radiation emitted, and in particular scattered, from the surface to be inspected at an additional emission angle in response to irradiation.

[0031] Preferably, the image recording device, and preferably two image recording devices, are arranged such that the image recording device, and preferably two image recording devices, record radiation emitted from the surface to be inspected in a vertical direction (relative to the surface to be inspected).

[0032] Preferably, at least one of the image recording devices is an image camera, and particularly a color image camera. Particularly preferably, both image recording devices are color image cameras.

[0033] In another preferred embodiment, the second image recording device has a higher recording resolution than the first image recording device, or (especially in combination with an objective lens) is capable of achieving a higher image resolution than the first image recording device. In particular, the second image recording device is capable of achieving microscopic imaging of surfaces and / or image resolution of individual effect pigments.

[0034] Preferably, the first image recording device is capable of achieving a magnification factor of the surface, wherein the magnification factor is greater than 0.2, preferably greater than 0.3, preferably greater than 0.4, and preferably greater than 0.5 (this means that the image size is reduced relative to the actual size of the surface). Preferably, the first image recording device is capable of achieving a magnification factor of the surface, wherein the factor is less than 1.2, preferably less than 1.0, preferably less than 0.9, and particularly preferably less than 0.8.

[0035] The second image capturing device is preferably capable of magnifying the surface or the magnification factor, that is, the magnification of the image relative to the actual surface, with a factor greater than 2.0, preferably greater than 3.0, and preferably greater than 4.0.

[0036] Particularly preferably, the second image recording device is capable of magnifying the surface or the image of the surface and / or having a magnification factor less than 15, preferably less than 12, preferably less than 10, preferably less than 8, preferably less than 7, and preferably less than 6. Particularly preferably, the magnification factor is approximately 5.

[0037] The first image recording device is preferably adapted and intended to record images of surfaces suitable for characterizing the visual properties caused by effect pigments.

[0038] The applicant was able to determine that a magnification factor of approximately 5 represents a good trade-off between not making the optics overly complex on the one hand and achieving a usable magnification of the image on the other hand (especially for examining effect pigments).

[0039] In particular, the second image recording device shall be adapted and intended to record a plurality of images, which are adapted to measure or determine the properties of individual effect pigments from these images, such as the size, shape, orientation, color and / or color gradient of the individual effect pigments.

[0040] In another advantageous embodiment, the device has a housing in which a first radiating device, an optional second radiating device, a first image recording device, and a second image recording device are arranged. Particularly preferably, the housing has an opening through which the first radiating device and the optional second radiating device illuminate the surface to be inspected. Preferably, this is the only opening in the housing through which external light can reach the image recording device and / or through which radiation can escape from the housing.

[0041] In a preferred embodiment, the device is a portable device or a device that a user can carry without assistance.

[0042] Preferably, the weight of the device is less than 3 kg, more preferably less than 2 kg, and particularly preferably less than 1 kg. Preferably, a control device for controlling the radiation device and / or the image recording device is also arranged in the housing. Furthermore, a storage device for storing the recorded images is also provided in the housing.

[0043] Particularly preferably, the aforementioned objective lens is integrated into the housing.

[0044] In another advantageous embodiment, a first objective lens device is assigned to a first image recording device, and / or a second objective lens device is assigned to a second image recording device, wherein the second objective lens device preferably has a longer objective lens length than the first objective lens device.

[0045] Preferably, at least one aperture is arranged in the optical path between the surface to be inspected and the second image recording device. Preferably, several apertures are arranged in the optical path. Particularly preferably, at least one of these apertures is arranged in one of the objective lens devices, and particularly in the second objective lens device.

[0046] Particularly preferably, the length of the second objective lens assembly (along the optical path) is at least 1.5 times the length of the first objective lens assembly, preferably at least 2.0 times the length.

[0047] Particularly preferably, the two objectives extend in different directions, and particularly preferably in directions perpendicular to each other. Particularly preferably, the objectives extend in the same plane.

[0048] In another advantageous embodiment, the first image recording device and the second image recording device are arranged such that they can record the surface at the same recording angle. Specifically, the arrangement of the first and second image recording devices, or the arrangement of the first and second image recording devices, allows the surface to be viewed from a substantially perpendicular direction. A substantially perpendicular viewing direction is understood to mean that the deviation of the viewing angle from a completely perpendicular direction does not exceed 10°, preferably not more than 7°, preferably not more than 5°, and preferably not more than 3°.

[0049] The first image recording device and the second image recording device can also realize or perform surface recording at different recording angles.

[0050] In another advantageous embodiment, the device has a first beamsplitter arrangement positioned between the image recording device and the surface to be inspected. This beamsplitter arrangement can be used to ensure, for example, that both image recording devices are viewing the surface from the same angle. The beamsplitter arrangement can be designed such that it allows the same amount of light to reach both image recording devices.

[0051] However, the beam splitter device can also, and preferably is, designed to allow more light to reach the second image recording device. Preferably, the ratio of the amount of radiation reaching the first image recording device to the amount of radiation reaching the second image recording device is between 1:1 and 1:5, more preferably between 1:1 and 1:4, more preferably between 1:1 and 1:3, and particularly preferably between 1:1.5 and 1:3.

[0052] In another advantageous embodiment, the device has a second beamsplitter arrangement positioned between the image recording device and the surface. In this way, it can be coupled to different receiving and / or image recording devices at two locations.

[0053] Particularly preferably, the first beam splitter device and the second beam splitter device are arranged in series in the optical path between the surface and at least one image recording device, and preferably in series in the optical path between the surface and two image recording devices.

[0054] In another preferred embodiment, at least one beamsplitter device is selected from a set of beamsplitter devices, which includes a beamsplitter plate, a beamsplitter cube, and a thin film. The thin film is an ultrathin, ultralight, translucent mirror used in the spot of an optical instrument to split a light beam into two parallel beams, both with reduced light intensity. This beam splitting allows the beam to be used for several purposes simultaneously. Due to weak secondary reflections from a nominally non-reflective surface, the thin film virtually eliminates beam and image duplication.

[0055] Preferably, the film is a very thin membrane, particularly a cellulose membrane, and especially an optically high-quality nitrocellulose membrane (or thin layer), which is stretched and bonded to a body, particularly a ring and especially an aluminum ring. Functionally, the thin-film beam splitter serves the same purpose as a conventional plate beam splitter. Upon close observation, a plate beam splitter (or a "mirror-type" beam splitter) produces two reflected beams for a single input beam. One beam is a reflection from a first (or front) surface, and the second beam is a reflection from a second (or rear) surface.

[0056] The result is what is known as "ghosting" or secondary reflection. Furthermore, due to the thickness of the glass substrate (1-3 mm, depending on size), the plate beam splitter causes the transmitted beam to be slightly deflected laterally from the input beam. For these reasons, the plate beam splitter minimizes these effects and provides optimal performance when the glass thickness is minimal, the coated surface is aligned with the light source, the plate beam splitter is used under collimated beam conditions, and the rear surface is coated with AR (anti-reflective).

[0057] In another advantageous embodiment, the device has a third emitting device adapted and intended to irradiate radiation onto the surface to be inspected along a third emitting direction characterized by a third emitting angle.

[0058] Preferably, the irradiation angle at which the irradiating device irradiates the surface relative to the vertical direction is between 30° and 60°, more preferably between 35° and 55°, more preferably between 40° and 50°, and particularly preferably between 42° and 48°.

[0059] Preferably, the first radiating device and / or the second radiating device emit directional radiation. Preferably, the first radiating device and / or the second radiating device have a light source in the form of at least one white LED.

[0060] Preferably, the radiating device irradiates the surface at an angle between 60° and 90° relative to the vertical direction, preferably between 65° and 85°, more preferably between 70° and 80°, and particularly preferably between 72° and 78°. Preferably, the radiating device irradiates directional radiation. Preferably, the first radiating device and / or the second radiating device have a light source in the form of at least one white LED.

[0061] Preferably, the radiating device irradiates the surface at an angle between 5° and 25° relative to the vertical direction, preferably between 10° and 20°, more preferably between 12° and 18°, and particularly preferably between 14° and 16°. Preferably, the radiating device irradiates directionally. Preferably, the first and / or second radiating devices have a light source in the form of at least one white LED.

[0062] In another preferred embodiment, diffuse illumination of the surface is also provided. White LEDs can also be used for this purpose. An integrating sphere can be used to achieve this diffuse illumination.

[0063] In this case, light is preferably irradiated onto the surface at at least three different angles.

[0064] The device preferably has a fourth irradiation device adapted and designed to irradiate radiation onto the surface to be inspected along a fourth irradiation direction, characterized by a fourth irradiation angle. In this design, light is thus irradiated onto the surface from at least four different directions.

[0065] In another preferred embodiment, the device has an additional irradiation device adapted and intended to diffusely irradiate the surface. Preferably, the additional irradiation device also has at least one white LED.

[0066] Preferably, a scattering surface, particularly a scattering surface in the form of a so-called Ulbricht sphere, is provided to generate this diffuse illumination. The Ulbricht sphere is a component of technical optics. It is used as a light source to achieve diffuse radiation from directional radiation or to collect radiation from highly divergent sources.

[0067] This is preferably a hollow sphere with internal diffuse reflection, and on the surface of the hollow sphere, there is (often) an exit opening perpendicular to the light-entry opening. The light source or radiation source is located in front of the light-entry opening. The inner coating is composed of a material with optimal diffuse reflection properties. Barium sulfate (BaSO4) is a preferred material. However, good reflectivity can also be achieved over a wide wavelength range using optical PTFE.

[0068] Preferably, a control device is provided to ensure that at most one irradiation device irradiates the surface during a specified time period.

[0069] In another advantageous embodiment, the second image recording device is capable of achieving an image resolution with an active pixel count between 1500 x 1200 and 3000 x 2500, preferably between 2000 x 1500 and 2800 x 2300, and particularly preferably between 2300 x 1800 and 2700 x 2000.

[0070] Preferably, the pixel size is between 1.0 μm x 1.0 μm and 4.0 μm x 4.0 μm, more preferably between 1.2 μm x 1.2 μm and 3.0 μm x 3.0 μm, and more preferably between 1.5 μm x 1.5 μm and 2.5 μm x 2.5 μm.

[0071] In another preferred embodiment, the focal length of the objective lens associated with the second image recording device is greater than 1.0 mm, preferably greater than 2.0 mm, preferably greater than 2.5 mm, preferably greater than 3.0 mm, preferably greater than 3.5 mm, preferably greater than 4.0 mm, and particularly preferably greater than 4.5 mm.

[0072] Preferably, the focal length of the objective lens associated with the second image recording device is less than 50 mm, preferably less than 40 mm, preferably less than 30 mm, preferably less than 20 mm, preferably less than 15 mm, preferably less than 10 mm, preferably less than 8.0 mm, preferably less than 7.0 mm, and particularly preferably less than 6.0 mm.

[0073] In another preferred embodiment, the focal length of the objective lens associated with the first image recording device is greater than 2.0 mm, preferably greater than 3.0 mm, preferably greater than 4.0 mm, preferably greater than 6.0 mm, preferably greater than 8.0 mm, preferably greater than 10.0 mm, and particularly preferably greater than 12.0 mm.

[0074] Preferably, the focal length of the objective lens associated with the first image recording device is less than 50 mm, preferably less than 45 mm, preferably less than 40 mm, preferably less than 35 mm, preferably less than 30 mm, preferably less than 25 mm, preferably less than 20 mm, preferably less than 18.0 mm, and particularly preferably less than 16.0 mm.

[0075] These focal lengths have proven particularly advantageous for imaging the corresponding good surfaces (especially when installation space is also limited).

[0076] In another preferred embodiment, the properties of the effect pigment are selected from a set of properties including the size of the effect pigment, the geometry of the effect pigment, the color of the effect pigment, the curvature of the effect pigment, the orientation of the effect pigment, the tilt of the effect pigment in the surface, the manufacturer of the surface, the manufacturer of the effect pigment, the material of the effect pigment, etc.

[0077] In another preferred embodiment, the evaluation device is adapted and intended to use artificial intelligence to determine the characteristics of the representative effect pigment.

[0078] Preferably, artificial intelligence is used to perform image evaluation, particularly of images recorded by the second image recording device. Particularly preferably, a machine learning image evaluation model is created for evaluating the images.

[0079] The image evaluation model for machine learning is preferably based on (artificial) neural networks. The neural network is preferably a deep neural network (DNN) and / or a so-called convolutional neural network (CNN) and / or a recurrent neural network (RNN), in which a parameterizable processing chain has multiple processing layers.

[0080] Preferably, the data (to be processed), particularly spatially resolved images (or data derived from spatially resolved images), is supplied as input variables to an image evaluation model or an (artificial) neural network. Preferably, the image evaluation model or artificial neural network maps the input variables to output variables according to a parameterizable processing chain, wherein the output variables preferably include the type of effect pigment, the size of the effect pigment and / or individual effect pigments, the size range of the effect pigment and / or individual effect pigments, the number of effect pigments per unit area, the size variation of the effect pigment, the tilt of the effect pigment and / or individual effect pigments, the curvature of the effect pigment, the color of the effect pigment, the curvature distribution profile of the effect pigment and / or individual effect pigment, or the type of effect pigment (i.e., whether the effect pigment is a metallic effect pigment, a pearlescent pigment, an interference pigment, or a glitter pigment).

[0081] Preferably, a machine learning image evaluation model is trained / trained using predetermined training data, wherein the training parameterizes a parameterizable processing chain.

[0082] In a preferred method, training data is used during the training of the image evaluation model. This training data comprises multiple spatially resolved images (of the surface being examined with effect pigments) recorded by at least one image recording device, and particularly a second image recording device. This provides the advantage that the training process has been specifically tailored to the testing apparatus and / or image recording device (including its optics) used and / or to be used, and therefore, for example, specific conditions of the particular apparatus, such as the optical characteristics of the image recording device or the specific lighting conditions in the testing apparatus, can be directly considered.

[0083] Preferably, the spatially resolved image (recorded by at least one image recording device, i.e., a second image recording device) intended to be used as training data is provided with (surface) type and / or classification features.

[0084] In addition, parameters used for optical settings when recording a single image, such as parameters about the aperture or lens used, or even the objective lens used, can also be used to create training data.

[0085] Preferably, the spatially resolved image, together with the surface type and / or effect pigment type and / or features (color, material, manufacturer, type of effect pigment, etc.) and / or classification features representing the characteristics of the effect pigment, is stored as and / or used as a training dataset (particularly stored as and / or used as a training dataset together on volatile and / or non-volatile storage devices). Preferably, multiple training datasets are generated in this manner.

[0086] The classification characteristics may preferably be the type of effect pigment, the genus of the effect pigment (i.e., whether the effect pigment is a metallic effect pigment, pearlescent pigment, interference pigment, or glitter pigment), the size of the effect pigment and / or individual effect pigments, the size range of the effect pigment and / or individual effect pigments, the number of effect pigments per unit area, the size variation of the effect pigments, the tilt of the effect pigment or individual effect pigments, the curvature of the effect pigments, the color of the effect pigments, the curvature distribution profile of the effect pigments or individual effect pigments, the manufacturer of the effect pigments or surface, or even the characteristics of additional layers of the surface.

[0087] The use of machine learning image evaluation models ensures the identification or determination of (complex) combinations of different features and / or reference ranges that are optimal for data processing (during training), as well as features (or combinations of features) applicable to a wide variety of surface types and / or effect pigment types.

[0088] This provides the advantage that when evaluating at least one spatially resolved image using a trained image evaluation model, characteristic parameters of the surface and / or effect pigments, such as the size, color, tilt, and density of the effect pigments, can be determined with high accuracy.

[0089] Furthermore, effect pigments can differ in properties such as brightness, dynamics, density, color gradient, or other characteristics of color.

[0090] The effect pigment preferably has an intermediate particle area between 15 µm² and 700 µm², and more preferably between 30 µm² and 500 µm².

[0091] For example, effect pigments can be selected from the following types: Effect pigments can be, for example, metallic effect pigments (e.g., aluminum flakes). The particle size of these metallic effect pigments is preferably between 5 µm and 50 µm. Smaller particles, particularly those between 5 µm and 20 µm, produce a smooth, fine metallic appearance. Larger particles (especially those between 20 µm and 50 µm) produce a more intense shimmering effect.

[0092] Furthermore, the effect pigments can be pearlescent pigments, for example, those based on glitter, titanium dioxide, or silica. The particle size of these pearlescent pigments is preferably between 5 µm and 60 µm. Fine particles (especially those with a particle size between 5 µm and 20 µm) produce a subtle, silky sheen. Coarser particles (especially those with a particle size between 20 µm and 60 µm) provide a stronger shimmering and reflective effect.

[0093] Furthermore, effect pigments can be interference pigments. The particle size of these interference pigments is preferably between 5 µm and 50 µm. Interference pigments are often compared to pearlescent pigments because they are based on similar materials.

[0094] Finally, effect pigments can be glitter pigments. These glitter pigments preferably have a particle size between 5 µm and 200 µm (or even larger). Such glitter pigments produce a striking glitter effect and are frequently used in specialty coatings or tinting coatings.

[0095] Effect pigments may also have one or more oxide layers.

[0096] The effect pigments are preferably effect pigment flakes. These effect pigment flakes are preferably incorporated into a surface layer or into a coating on the surface.

[0097] In another preferred embodiment, at least the magnification factor of the second image recording device is variable so as to be applicable to different surfaces.

[0098] In another preferred embodiment, at least one of the image recording devices and / or at least one objective lens associated with at least one image recording device (and preferably two image recording devices and / or objective lenses associated with the two image recording devices) has an autofocus mechanism. This is particularly helpful because the individual magnifying optics, especially those associated with the second image recording device, have a relatively shallow depth of field.

[0099] In another advantageous embodiment, the evaluation device has a memory in which reference data of the effect pigment or effect pigment group is stored. Furthermore, recorded images or image data may also be stored in the memory device.

[0100] The present invention also relates to a method for inspecting the optical properties of a surface, particularly a surface coated with an effective pigment, wherein a first radiating device irradiates the surface to be inspected along a first irradiation direction characterized by a first irradiation angle; and preferably, a second irradiating device irradiates the surface to be inspected along a second irradiation direction characterized by a second irradiation angle (wherein the first irradiation angle and the second irradiation angle are preferably different), and wherein a first image recording device records at least one spatially resolved image of the surface irradiated by at least one of the irradiating devices.

[0101] According to the present invention, the second image recording device records a spatially resolved image of the surface, and in particular records a spatially resolved image of the surface irradiated by at least one of the irradiation devices.

[0102] Preferably, the image recorded by the second image recording device is a color image; that is, the second image recording device is preferably adapted and intended to record color images. Preferably, the first image recording device is also adapted and intended to record color images.

[0103] The present invention also relates to a method for inspecting the optical properties of a surface, and particularly a surface provided with an effective pigment, wherein a first radiating device irradiates radiation onto the surface to be inspected along a first irradiation direction, the first irradiation direction being characterized by a first irradiation angle.

[0104] Preferably, the second irradiation device also irradiates the surface to be inspected along the second irradiation direction, which is defined by the second irradiation angle.

[0105] In addition, the first image recording device records at least one spatially resolved image of the surface irradiated by the radiation device or at least one of the radiation devices.

[0106] In addition, the evaluation device evaluates the image recorded by the second image recording device to determine at least one characteristic representing the characteristics of the effect pigment and / or a single effect pigment.

[0107] In another preferred method, the second image recording device records a higher resolution image of the surface compared to the first image recording device, and in particular, records a microscopic image of the surface.

[0108] Particularly preferably, the second image recording device magnifies the recorded image (relative to the surface to be inspected) by a predetermined coefficient, which is preferably greater than 2, preferably greater than 3, and preferably less than 4. This coefficient is preferably less than 40, preferably less than 30, preferably less than 25, preferably less than 20, preferably less than 15, preferably less than 8, and preferably less than 6.

[0109] Preferably, the radiating device irradiates the surface with two, and more preferably several, different colors or wavelengths.

[0110] In another preferred method, the first image recording device and the second image recording device record images of the surface at the same recording angle.

[0111] In another preferred method, the second image recording device magnifies the recorded image (relative to the actual surface) by more than 2 times, preferably more than 3 times, preferably more than 4 times, preferably more than 5 times, or equal to 5 times.

[0112] Preferably, the second image recording device is capable of magnification (relative to the surface) of less than 20 times, preferably less than 15 times, preferably less than 10 times, preferably less than 8 times, particularly preferably less than 7 times, and particularly preferably less than 6 times.

[0113] In another preferred method, radiation reflected and / or scattered by the surface is split by a beamsplitter before reaching the second image recording device. Particularly preferably, the optical path from the surface to be inspected to the image recording device passes through at least two beamsplitter devices.

[0114] Preferably, the surface is irradiated at at least three different angles, and more preferably at at least four different angles.

[0115] Preferably, light is irradiated onto the surface at a 45° angle, and the radiation reflected from the surface is detected by a detection device. Preferably, a detection device is provided that detects the intensity of the radiation incident on the detection device.

[0116] Particularly preferably, at least one radiating device is altered to change the color of the light it irradiates onto the surface. This is preferably accomplished by a filter assembly and / or a filter wheel.

[0117] Preferably, the surface to be inspected is recorded by a second image recording device with an exposure time greater than 1 ms, preferably greater than 2 ms, preferably greater than 4 ms, preferably greater than 6 ms, preferably greater than 8 ms, preferably greater than 10 ms, preferably greater than 12 ms, preferably greater than 14 ms, preferably greater than 16 ms, preferably greater than 18 ms, preferably greater than 20 ms, and preferably greater than 25 ms.

[0118] Preferably, the surface to be inspected is recorded by a second image recording device with an exposure time less than 500 ms, preferably less than 400 ms, preferably less than 300 ms, preferably less than 200 ms, preferably less than 150 ms, preferably less than 120 ms, preferably less than 100 ms, particularly preferably less than 90 ms, and particularly preferably less than 85 ms.

[0119] Preferably, the apparatus and / or method described herein are designed to allow inspection of two original surfaces, such as the original surfaces of an object and, in particular, the original surfaces of a motor vehicle, i.e., those surfaces that exist on the motor vehicle in its manufactured state, and those surfaces that are subsequently applied (e.g., as a result of an accident).

[0120] Preferably, the surface to be inspected is a painted surface. Preferably, the thickness of these surfaces (perpendicular to the surface extension) is greater than 20 μm, more preferably greater than 40 μm, more preferably greater than 60 μm, and particularly preferably greater than 80 μm. In another preferred embodiment, the surface thickness is less than 400 μm, more preferably less than 350 μm, and more preferably less than 200 μm.

[0121] The surface to be inspected preferably consists of at least three layers, preferably at least four layers, and particularly preferably at least five layers. The surface to be inspected preferably consists of at most 12 layers, preferably at most 10 layers, and preferably at most 8 layers.

[0122] These specifications are of vital importance to the optical parameters of the second image recording device and / or the objective lens associated with the second image recording device. Preferably, the effect pigment is located in the intermediate layer of the surface to be inspected. Attached Figure Description

[0123] Further advantages and practicality can be found in the following description taken in conjunction with the accompanying drawings. In the drawings: Figure 1 A schematic representation of the device according to the invention is shown; Figure 1a A schematic representation of another device according to the invention is shown.

[0124] Figures 2a to 2c Showing from Figure 1 A detailed description of the equipment; Figure 3 A representation of the image recorded by the second image recording device is displayed; and Figures 4a to 4c Three views are shown of another embodiment of the device according to the invention. Detailed Implementation

[0125] Figure 1 A schematic representation of a device 1 according to the invention is shown. Device 1 has an optical block 51 and a housing 50, in which electrical and optical components, described in detail below, are arranged. The housing has an opening 52 through which the surface 10 to be inspected can be irradiated or illuminated, and radiation reflected and / or scattered by the surface returns to the interior of the housing 50 through the opening 52.

[0126] Reference numeral 2 indicates a first radiating device that radiates, specifically, light, onto the surface 10 along the irradiation direction R1 and at an irradiation angle α1 relative to the surface 10. Preferably, a filter wheel (not shown in detail) is provided, arranged in the beam path between the first radiating device 2 and the surface. This filter wheel preferably has multiple color filters, through which light of different colors or wavelengths can be irradiated onto the surface 10.

[0127] Reference numeral 4 indicates a second (optional) radiating device that radiates, in particular, light onto the surface 10 along the irradiation direction R2 and at an irradiation angle a2 relative to the surface 10.

[0128] Reference numeral 32 indicates a third (optional) radiating device that radiates, in particular, light onto the surface 10 along a different irradiation direction and at a different irradiation angle relative to the surface 10.

[0129] Reference numeral 6 indicates a first image recording device, which is arranged vertically relative to surface 10 and records a first image of the surface. For this purpose, the first image recording device preferably records radiation scattered by surface 10 (or a portion of surface 10).

[0130] Preferably, an image magnification of approximately 0.7 can be achieved through the first image recording device 6 and the optical devices associated with the first image recording device 6. Preferably, the size of the corresponding observation point is between 6.0 mm x 4.0 mm and 12.0 mm x 9.00 mm, and more preferably between 7.0 mm x 5.0 mm and 9.0 mm and 7.0 mm.

[0131] Preferably, the image ratio of the first image recording device is between 2.0 µm / pixel and 4.0 µm / pixel.

[0132] Reference numeral 8 indicates a second image recording device having optics described in more detail below. The second image recording device is preferably also arranged such that it records an image of a surface illuminated by at least one radiating device in a vertical direction. As explained above, the second image recording device can achieve a significantly higher resolution of the recorded image compared to the first image recording device. Reference numeral 25 indicates an aperture.

[0133] Preferably, an image magnification of approximately 5 is achieved through the second image recording device 8 and the optics associated with the second image recording device 8. Preferably, the size of the corresponding observation point is between 0.9 mm x 0.6 mm and 1.8 mm x 1.6 mm, and more preferably between 1.0 mm x 0.8 mm and 1.4 mm and 1.1 mm.

[0134] Preferably, the image ratio of the second image recording device is between 0.3 µm / pixel and 0.55 µm / pixel.

[0135] Reference numeral 28 indicates a lens, and in particular an achromatic lens, which preferably forms an entrance for radiation from the surface to the image recording apparatus.

[0136] Preferably, the distance between the lens 28 and the surface 10 is greater than 20 mm, preferably greater than 30 mm, preferably greater than 40 mm, and particularly preferably greater than 45 mm. Preferably, the distance between the lens 28 and the surface is less than 90 mm, preferably less than 80 mm, preferably less than 70 mm, preferably less than 60 mm, and particularly preferably less than 55 mm.

[0137] Figure 1a Another representation of the device according to the invention is shown, wherein, for clarity, the second image recording device is not shown here. The device has a generating device 60 for generating diffuse radiation, and the generating device 60 is in the form of a so-called Ulbricht sphere (integral sphere) 60. Reference numeral 62 indicates an irradiation device, such as a white LED, for irradiating the generating device 60.

[0138] Figure 2a The optical structure or arrangement capable of recording images by two image recording devices 6 and 8 is schematically shown. Light originating from surface 10 propagates upward from the surface (not shown) in a vertical line.

[0139] Reference numeral 42 indicates the first lens assembly, through which radiation originating from the surface passes.

[0140] Reference numeral 22 indicates a beam splitter that transmits a portion of the radiation and couples out another portion of the radiation, reflecting it to a separate radiation detection device (not shown). This separate radiation device is adapted and intended to detect the intensity of the radiation incident upon it. Preferably, this portion of the radiation is reflected in a direction perpendicular to the plane of the figure.

[0141] Reference numeral 44 indicates a second lens assembly through which radiation originating from the surface passes. This second lens assembly is preferably arranged between the first beam splitter assembly 22 and the second beam splitter assembly 24.

[0142] Reference numeral l1 indicates the distance between the first lens assembly 42 and the second lens assembly. This distance is preferably greater than 10 mm, preferably greater than 12 mm, preferably greater than 14 mm, preferably greater than 16 mm, preferably greater than 18 mm, and particularly preferably greater than 20 mm. Furthermore, this distance l1 is preferably less than 50 mm, preferably less than 40 mm, preferably less than 35 mm, preferably less than 30 mm, and particularly preferably less than 25 mm. These distance limitations were determined by the applicant through extensive investigation to achieve a particularly advantageous design for the optical arrangement.

[0143] Reference numeral 24 indicates a beam splitter, referred to as the first beam splitter device above, which splits the radiation incident on it into a first part and a second part (preferably larger than the first part), the first part reaching the first image recording device 6 and the second part reaching the second image recording device 8.

[0144] Reference numeral 16 indicates a first objective lens device associated with the first image recording device 6, and reference numeral 18 indicates a second objective lens device associated with the second image recording device 8. It can be seen that the second objective lens device 18 is significantly longer than the first objective lens device 16.

[0145] Preferably, the second objective lens assembly is at least twice the length of the first objective lens assembly. Preferably, the second objective lens assembly is at most four times the length of the first objective lens assembly 16. Preferably, the second objective lens assembly 18 extends perpendicular to the first objective lens assembly 16.

[0146] Lens assembly 46 is arranged within the first objective lens assembly 16, and second lens assembly 48 is arranged within the second objective lens assembly 18.

[0147] Therefore, an optical arrangement 30 is provided in general, which is capable of image recording by the first image recording device 6 and the second image recording device 8. Preferably, the optical arrangement 30 has at least two separate lens assemblies, preferably three separate lens assemblies, and particularly preferably four separate lens assemblies.

[0148] Reference numeral 36 denotes a first aperture, which is preferably disposed in the first objective lens assembly 16. Preferably, the first aperture 36 is disposed between the beam splitter assembly 24 and the first image recording device. Preferably, the cross-sectional area of ​​the aperture is greater than 0.5 mm, more preferably greater than 1.0 mm, and more preferably greater than 1.5 mm. Preferably, the cross-sectional area of ​​the aperture is less than 10 mm, more preferably less than 8.0 mm, more preferably less than 6.0 mm, particularly preferably less than 4.0 mm, and particularly preferably less than 3.0 mm.

[0149] Reference numeral 38 indicates a second hole, which is preferably arranged between the beam splitter plates. Preferably, the cross-section of the second hole is greater than 2.0 mm, more preferably greater than 4.0 mm, and more preferably greater than 6.0 mm. Preferably, the cross-section of the second hole is less than 16 mm, more preferably less than 14.0 mm, more preferably less than 12.0 mm, particularly preferably less than 10.0 mm, and particularly preferably less than 9.0 mm.

[0150] Preferably, the size of the second hole is greater than 8 mm, more preferably greater than 10 mm, more preferably greater than 11 mm, particularly preferably greater than 12 mm, particularly preferably greater than 14 mm, and particularly preferably greater than 15 mm.

[0151] Preferably, the size of the second hole 36 is less than 25 mm, more preferably less than 22 mm, more preferably less than 20 mm, more preferably less than 18 mm, and particularly preferably less than 17 mm. Preferably, the first hole 36 is arranged between the beam splitter device 24 and the second image recording device 8.

[0152] The reference numeral l2 indicates the distance between the lens assembly 44 and the first aperture.

[0153] The distance is preferably greater than 6 mm, preferably greater than 8 mm, preferably greater than 10 mm, preferably greater than 11 mm, preferably greater than 12 mm, and particularly preferably greater than 14 mm. Furthermore, the distance is preferably less than 40 mm, preferably less than 30 mm, preferably less than 25 mm, preferably less than 20 mm, and particularly preferably less than 17 mm. These distance limitations were determined by the applicant through extensive investigation to achieve a particularly advantageous design for the optical arrangement.

[0154] Figure 2b Another embodiment of the optical structure is shown. In this embodiment, beam splitter cubes 22a and 24a are used instead of beam splitter plates 22 and 24.

[0155] Figure 2c The optical setup inside the device's housing is shown.

[0156] Figure 3 An example of an image recorded by a second image recording device is shown. This image was recorded with the first lens group having an aperture of 16 mm and an exposure time of 30 ms.

[0157] Here you can see multiple individual effect pigments. Using appropriate image analysis, and if necessary, artificial intelligence (AI), various data about the effect pigments can be output. For example, the color of the effect pigment, or the proportion of those effect pigments having a certain color, can be determined.

[0158] Furthermore, the number of effect pigments per unit area can be determined. Additionally, values ​​such as the size of an individual effect pigment or the average size of the effect pigments can be determined. The curvature of the effect pigments, or values ​​representing characteristics of the color behavior of the effect pigments, such as values ​​indicating how the effect pigments behave when illuminated from different directions, can also be determined.

[0159] In doing so, the AI ​​can preferably access a very large number of images, such as Figure 3 As shown, this is to enable an objective statement about the effect pigments.

[0160] Figures 4a to 4cAnother embodiment of the device 1 according to the invention is shown. A first image recording device 6 and a second image recording device 8 are also provided herein. Preferably, the second image recording device is an image recording device having an autofocus unit, and / or the image recording device is capable of autofocus.

[0161] However, in Figures 4a to 4c In the embodiment shown, the second image recording device 8 is arranged laterally adjacent to the first image recording device 6, such as... Figure 4b This can be seen in the image. Preferably, compared to the first image recording device, the second image recording device observes slightly different or offset areas of the surface to be inspected.

[0162] In this embodiment, a second image recording device is proposed to be designed as a separate unit. Reference numeral 82 denotes an objective lens 82, which has a lens 84. Reference numeral 86 denotes an illumination device for illuminating a surface. This illumination device is preferably designed for annular illumination, and preferably at least partially surrounds the lens 84 with respect to the viewing direction. Preferably, the illumination device is equipped with at least one LED, and particularly preferably with multiple LEDs.

[0163] Therefore, preferably, the second image recording device 8 also observes the surface 10 from the vertical direction, but preferably, as mentioned above, observes the area of ​​the lateral offset of the surface 10.

[0164] It should be noted that all features described in the reference method are also disclosed in a corresponding manner for use with the device, specifically meaning that the corresponding device has means suitable for and intended to perform the corresponding method. Furthermore, the features described in the reference device are also applicable to one or more methods. This means that the method is performed using the corresponding device features.

[0165] The applicant reserves the right to claim all features essential to the invention disclosed in the application documents, provided that all features, individually or in combination, are novel compared to the prior art. It should also be noted that a single figure also depicts a feature that may be advantageous in itself. Those skilled in the art will readily recognize that the specific features described in the figures can be advantageous even without employing other features from the figures. Furthermore, those skilled in the art will recognize that advantages can also arise from combinations of several features shown in a single figure or different figures.

Claims

1. An apparatus (1) for inspecting the optical properties of a surface (10) comprising an effect pigment, the apparatus having a first irradiation device (2) and a first image recording device (6), the first irradiation device being adapted and intended to irradiate radiation onto the surface (10) to be inspected along a first irradiation direction (R1), the first irradiation direction being characterized by a first irradiation angle (a1), and the first image recording device being adapted to record a spatially resolved image of the surface irradiated by the first irradiation device. Its features are, The device (1) has a second image recording device (8) and an evaluation device, the second image recording device being adapted to record a spatially resolved image of the surface (10) irradiated by the first irradiation device (2), and the evaluation device being adapted and intended to evaluate the image recorded by the second image recording device (8) to determine at least one property representing the characteristics of effect pigments and / or individual effect pigments.

2. The device (1) according to claim 1, characterized in that, The device has a second radiation device (4) adapted and intended to irradiate the surface to be inspected (10) along a second irradiation direction (R2), the second irradiation direction being characterized by a second irradiation angle (a2).

3. The device (1) according to at least one of the preceding claims, characterized in that, The properties of the effect pigment are selected from a set of properties including the size of the effect pigment, the geometry of the effect pigment, the color of the effect pigment, the curvature of the effect pigment, the orientation of the effect pigment, the amount of effect pigment per unit area, the surface or the manufacturer of the effect pigment, etc.

4. The device (1) according to at least one of the preceding claims, characterized in that, The evaluation device is adapted and designed to use artificial intelligence to determine the properties that represent the characteristics of the effect pigment.

5. The device (1) according to at least one of the preceding claims, characterized in that, The evaluation device has a storage device in which reference data of the effect pigment or effect pigment group is stored.

6. The device according to claim 1, characterized in that, The second image recording device (8) is capable of achieving a higher recording resolution than the first image recording device (6), and in particular, the second image recording device (8) is capable of microscopic recording of the surface (10).

7. The device according to at least one of the preceding claims, characterized in that, The device has a housing (50) in which the first radiation device (2), preferably the second radiation device (4), the first image recording device (6) and the second image recording device (8) are arranged. The housing (50) preferably has an opening (52) through which the first radiation device (2) and preferably the second radiation device (4) irradiate the surface (10) to be inspected.

8. The device according to at least one of the preceding claims, characterized in that, A first objective lens device (16) is assigned to the first image recording device (6), and a second objective lens device (18) is assigned to the second image recording device (8), wherein the second objective lens device (18) preferably has a longer objective lens length than the first objective lens device (16).

9. The device according to at least one of the preceding claims, characterized in that, The first image recording device (6) and the second image recording device (8) are arranged such that the first image recording device and the second image recording device can record the surface at the same recording angle.

10. The device according to at least one of the preceding claims, characterized in that, The device (1) has a first beam splitter device (22) arranged between the image recording device (6, 8) and the surface (10).

11. The device according to at least one of the preceding claims, characterized in that, The device (1) has a third irradiation device (32) adapted and intended to irradiate radiation onto the surface to be inspected along a third irradiation direction characterized by a third irradiation angle, and the device (1) preferably includes a fourth irradiation device adapted and intended to irradiate radiation onto the surface to be inspected (10) along a fourth irradiation direction characterized by a fourth irradiation angle.

12. The device according to at least one of the preceding claims, characterized in that, The second image recording device (8) is capable of magnification greater than 2 times, preferably greater than 4 times and preferably greater than or equal to 5 times; and / or the second image recording device (8) is capable of magnification less than 20 times, preferably less than 15 times, preferably less than 10 times and preferably less than 8 times.

13. The device according to at least one of the preceding claims, characterized in that, The objective lens associated with the second image recording device has a focal length greater than 5 mm, preferably greater than 7 mm, preferably greater than 9 mm, preferably greater than 11 mm, preferably greater than 12 mm, particularly preferably greater than 13 mm, particularly preferably greater than 14 mm; and / or the objective lens associated with the second image recording device has a focal length less than 40 mm, preferably less than 30 mm, preferably less than 25 mm, preferably less than 22 mm, preferably less than 20 mm, preferably less than 18 mm, particularly preferably less than 17 mm.

14. A method for inspecting the optical properties of a surface, particularly a surface provided with an effective pigment (10), wherein, The first radiation device (2) irradiates the surface to be inspected along the first irradiation direction (R1), which is characterized by the first irradiation angle (a1). The second radiation device (4) irradiates the surface to be inspected with radiation along the second irradiation direction (R1), the second irradiation direction being characterized by the second irradiation angle (a2); The first image recording device (6) records at least one spatially resolved image of the surface (10) irradiated by at least one of the irradiation devices. Its features are, The second image recording device (8) records a spatially resolved image of the surface (10) irradiated by at least one of the radiation devices (2, 4), and the evaluation device evaluates the image recorded by the second image recording device (8) to determine at least one property representing the characteristics of the effect pigment and / or a single effect pigment.

15. The method according to the preceding claims, characterized in that, Compared with the first image recording device (6), the second image recording device (8) records a higher resolution image of the surface (10), and in particular records a microscopic image of the surface (10); and / or the first image recording device (6) and the second image recording device (8) record images of the surface (10) at the same recording angle.

Images