Method for determining a mapping of a first color space of a test camera onto a second color space of a spectrometer

Abstract

The invention relates to a method (100) for determining a mapping of a first color space (R, G, B) of a test camera (K) onto a second color space (X, Y, Z) of a spectrometer (S) in order to test a vehicle component (P) in the second color space (X, Y, Z), said method (100) comprising the following steps: controlling an array of a plurality of light sources in order to generate a set of defined color spectra; detecting the set of defined color spectra in the second color space (X, Y, Z) using a spectrometer (S); detecting the set of defined color spectra in the first color space (R, G, B) using the test camera (K); determining a mapping of the first color space onto the second color space on the basis of the detected sets of defined color spectra in the second color space (X, Y, Z) and in the first color space (R, G, B); and applying the mapping to the test camera (K) in order to test the vehicle component (P) in the second color space (X, Y, Z).

Description

[0001] Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 1 Lisa Dräxlmaier GmbH Landshuter Str.100 D-84137 Vilsbiburg METHOD FOR DETERMINING AN IMAGE OF A FIRST COLOR SPACE OF A TEST CAMERA ONTO A SECOND COLOR SPACE OF A SPECTROMETER Technical field The present invention relates to a method and a testing system for determining an image of a first color space of a test camera on to a second color space of a spectrometer for testing a vehicle component in the second color space. The invention particularly relates to a test system-integrated system for RGB-to-XYZ transformation matrix generation for camera-based testing systems; a color and brightness adjustment for color cameras using a light element that is spectrally close to the test object; and a color and brightness adjustment for color cameras during component testing. State of the art Raw data values ​​from RGB image sensors (e.g. cameras) can be converted into standardized color models, orinto the standard color chromaticity system using linear matrix calculations. This is done using defined matrices for each color model and illuminant to be measured. As a rule, spectrally broadband standard illuminants such as D65, D50 are used for the standardized conversion matrices. Spectrally individual light sources to be measured are not taken into account in more detail, and when converting the RGB raw data into, for example, the standard color chromaticity system, increased conversion errors can occur depending on the light source to be measured. Color luminance cameras also offer the option of imaging the standard color chromaticity system values, but these are also generally calibrated to standard illuminants and are spectrally limited by the use of fixed color filters, which reduces measurement accuracy, and also slows the measurement time (sometimes > 1 s) due to the mechanical movement of the filters across the camera image sensor.In addition, they have a complex structure and are therefore extremely cost-intensive. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 2 Description of the invention One object of the invention is therefore to create a concept for testing test objects, in particular vehicle components, that is suitable for series testing due to easily implementable and therefore cost-effective system components. In particular, one object is to create a method and a testing system that converts RGB raw data into the standard color system using simply constructed standard color industrial cameras. This object is achieved by the subject matter of the independent claims. Advantageous developments of the invention are specified in the dependent claims, the description, and the accompanying figures.The inventive solution is based on the idea of ​​using a standard color industrial camera together with a spectrometer to determine a mapping of a first color space to a second color space using the color spectra thus acquired. The inventive solution is based on the combination of three sub-aspects, as described in more detail below. A first sub-aspect of the invention relates to a test system-integrated system for RGB-to-XYZ transformation matrix generation for camera-based test systems. The first sub-aspect of the invention relates to automated methods with sufficient accuracy for converting the raw data values ​​from standard color industrial cameras into physical quantities for photometric brightness perception and standardized color models (standard color intensity system, CIE 1931 XYZ, CIELUV). The following problems arise here, which are solved by the invention: Values ​​depending on the color model can only be calculated precisely using spectra.However, spectrometers do not produce images. Imaging systems such as cameras (color cameras, even multi- or hyperspectral cameras) have insufficient spectral resolution. Standard color industrial cameras typically have three intensity values ​​(R, G, B) for each pixel, representing the camera-typical irradiance for three spectral ranges (optical filters for "red," "green," "blue"). Due to the camera-specific optical filters, lenses, etc., these RGB values ​​cannot be directly converted into physical / photometric quantities or color models. A customized conversion matrix must be determined. The invention presented here provides a solution to these problems. With the method and testing system presented here, photometric measurement data is automatically collected using a spectrometer and raw camera data.This determines an individual, linear conversion matrix for RGB data to photometric data. This measurement data is recorded using a set of defined light spectra, which can be realized using a controllable light box. This set of defined light spectra can be created using light sources such as LEDs, which, depending on the LED type, have a variety of narrowband spectra in the visual range. The system presented here describes a unit that can, for example, be located entirely within an inline series testing station and can determine a conversion matrix from camera RGB raw data to the standard color system for the color industrial cameras used for series testing in a regular cycle. This enables the use of an attractively priced imaging inspection system with standard color industrial cameras that can deliver standardized measurement values ​​in the standard color system as images.This allows lighting components to be measured in this series test station according to OEM target specifications. Since only the cameras are located in the product inspection area, no production interruption is necessary during light box maintenance intervals. Even if the light box fails completely, the test station is still able to measure products with the cameras. This makes it possible to use familiar, standardized cameras not only to perform component tests but also to measure in the standard colorimetric system. The camera measurements can be generated without further increasing the product test cycle time. The conversion matrices can be created for each individual product to achieve the appropriate measurement accuracy within the expected measurement range. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 4 The cost-effective color industrial cameras used, with a corresponding conversion matrix, offer the option of being individually adjusted to the light product to be measured and of determining measured values ​​in the standard color system with very short measuring times (<< 0.5 s). In addition, selected standard components, such as industrial cameras, lenses, etc., which are quickly available on the market or can be replaced with equivalent components, can be used. The second partial aspect of the invention relates to a color and brightness adjustment for color cameras using a light element that is spectrally close to the test object. The following problems arise here, which are solved by the invention: A color and brightness adjustment is required for several system-fixed color cameras when measuring ambient lighting products with RGB LEDs (red, green, blue). A component test should be carried out in the standard color system (^^-, ^^-, ^^-color values) orin the CIELUV color space (according to CIE 1976 with luminance ^^, color coordinates ^^′ and ^^′). The color and brightness adjustment should be (partially) automated in the test system. The invention presented here creates a solution to these problems. The inventive method and test system presented here provides a fixed spectrometer and a fixed color camera (camera 1) that have the same detection range ("position 1"). Both measure (almost) simultaneously a specially developed light element (RGB LED light source, "calibration light source") that is placed in "position 1". Spectrometer measurement values ​​can be recorded in the standard colorimetric system (^^. Spec , ^^ Spec , ^^ Spec ) and camera values ​​in the camera RGB color space (^^ Cam , ^^ Cam , ^^ Cam) can be recorded. Camera 1 can be calibrated to the spectrometer using a “calibration sequence”. The “calibration light source” can then be moved to the next camera (camera 2) (“position 2”). The “calibration light source” can then be measured using camera 2. Camera 2 can be calibrated using the spectrometer’s measured values ​​determined at “position 1”. The “calibration light source” can then be moved to the next camera (camera 3) (“position 3”) and the “calibration light source” can be measured using camera 3. Camera 3 can be calibrated using the spectrometer’s measured values ​​determined at “position 1”. The process can be repeated in a similar manner for other cameras (“position 4”, “position 5”, etc.). Finally, the calibration light source can be returned to position 1 and a control measurement can be performed with the spectrometer to check whether changes toof the calibration light source during the calibration of all cameras. The system presented here describes a unit that can, for example, be located entirely in an inline series testing station, and which can determine a conversion matrix from camera RGB raw data to the standard color system for the color industrial cameras used for series testing in a regular cycle. This enables the use of an attractively priced, imaging testing system with standard color industrial cameras that can deliver standardized measured values ​​in the standard color system as an image. Thus, lighting components can be measured in accordance with OEM target specifications in this series testing station. Since only the cameras are located in the product testing area, no production interruption is necessary during maintenance intervals of the spectrometer or the calibration light source. Even in the event of a complete failure of the spectrometer and / or the calibration light source, the testing station is still capable ofThe cameras allow for continued measurement and testing of products. This makes it possible to use familiar, standardized cameras not only to perform component testing but also to measure in the standard color system. The camera measurement values ​​can be generated without further increasing the product test cycle time. The conversion matrices can be created for each product individually to achieve the appropriate measurement accuracy within the expected measurement range. The cost-effective color industrial cameras used, with the appropriate conversion matrix, offer the possibility of being individually adjusted to the light product to be measured and of determining measurement values ​​in the standard color system with very short measurement times (< 0.5 s). In addition, selected standard components, such as industrial cameras, lenses, etc., can be used, which are readily available on the market or can be replaced with equivalent components. The specially developed "calibration light source" contains identical lighting elements, for exampleRGB LEDs, like the product to be tested, can be controlled in the same way as the product to be tested. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 6. Therefore, there is no additional effort in cabling, control, etc. due to the "calibration light source." The third aspect of the invention relates to a color and brightness adjustment for color cameras during component testing. The following problems arise here, which are solved by the invention: A color and brightness adjustment is carried out from a point-measuring spectrometer (or spectroradiometer) to a surface-detecting color camera. With the adjusted color camera, every area in the camera image can be freely measured, not just point-measuring, but also, for example, across a surface or line. The light elements to be examined are, for example, RGB LEDs (red, green, blue), which can vary slightly spectrally in the respective color channel (so-called color binning variation).a general camera calibration (measurement) error that is not tailored to LED color binning, which should be minimized / avoided. At least one or more RGB LEDs should be measured. The invention presented here provides a solution to these problems. With the inventive method and test system presented here, each of the primary colors (red, green, blue) of the RGB LEDs can be measured (almost) simultaneously using the spectrometer and the color camera. The spectrometer's measurement point is located in the image field of the color camera. This allows multiple camera pixels to be referenced to the spectrometer measurement point. The measurement data from the spectrometer measurement point can be offset against the intensity values ​​of the pixel color channels of the color camera, and a separate "camera value to spectrometer value" conversion matrix can be determined for each RGB LED. This allows camera RGB raw data to be converted into the standard color system (^^-, ^^-, ^^-color values) and corresponding further color conversionsThis color information may be necessary, for example, for further component production steps and tests. When measuring multiple RGB LEDs, either the "spectrometer with camera" system should be movable, or a measurement point should be created that contains light information from all RGB LEDs. This disclosure considers the latter case. The system presented here describes a unit that can, for example, be located entirely in an inline series testing station. With the color industrial cameras used for series testing, a conversion matrix from camera RGB raw data to the standard color system can be determined for each test of an RGB LED. The conversion of the camera RGB values ​​is therefore more precise than pre-calibrated state-of-the-art measurement systems and can thus provide imaging color information with almost the same accuracy as spectrometers. This enablesthe use of an attractively priced, imaging inspection system with a standard color industrial camera and spectroradiometer, which can deliver standardized measurement values ​​in the standard color system as an image. Thus, lighting components can be measured and tested in accordance with OEM target specifications in this series test station. This enables high-quality and highly variable lighting component tests to be carried out. By using standard RGB industrial cameras with an additional spectroradiometer as well as freely programmable image evaluation software and the measurement sequence described below, the measurement system itself can be implemented without integrating other, expensive systems. The third aspect of the invention described in this disclosure offers, in particular, the following technical advantages: The free choice of standard RGB industrial cameras offers the advantage of market and availability independence. Thus, depending on availability, price and technicalAny RGB camera can be used for the requirements. Furthermore, familiar standard components, such as industrial cameras, lenses, etc., can be used, which are interchangeable with equivalent components. Since the cameras and the spectroradiometer are arranged in a fixed position within the test system but are not permanently installed together, they can be freely removed and replaced. This is particularly important when removing the spectroradiometer during the annual calibration routine. The RGB industrial camera does not need to be repositioned. Time-consuming readjustment can be minimized, simplifying this routine. A possible "dummy calibration" of the camera allows the camera to operate freely without a spectroradiometer. This allows the test system to "compensate" for a missing or defective spectroradiometer. However, this does result in a certain loss of accuracy. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 8 The measuring system(Camera+spectroradiometer) can compensate for product color variations (such as LED color binning) and maintain measurement accuracy. This also makes it possible to use other LED types with the same measurement system without losing measurement accuracy (e.g., during product updates or other derivatives). The measurements of the camera and the spectroradiometer can be performed synchronously, thus enabling very short measurement times (< 0.5 s) with measured values ​​in the standard color space. Inhomogeneities in the measurement point have a minimal impact on the overall result if the prerequisite is met that the spectroradiometer measurement point can be completely displayed in the camera image. However, this is usually done during initial setup and can thus be ensured. Even component position variations during the measurement are uncritical as long as the same measurement spot is evaluated (almost) simultaneously with the camera and spectroradiometer. When multiple LEDs are to be measured, it does not matter whether theyvary in color (LED color binning), since a separate conversion matrix "camera-to-spectroradiometer values" can be carried out for each of the RGB LEDs. According to a first aspect, the above-described object is achieved by a method for determining a mapping of a first color space (e.g., R, G, B) of a test camera to a second color space (e.g., X, Y, Z) of a spectrometer for testing a test object, in particular a vehicle component, in the second color space, wherein the method comprises the following steps: controlling an arrangement of a plurality of light sources to generate a set of predefined color spectra; detecting the set of predefined color spectra with a spectrometer in the second color space; detecting the set of predefined color spectra with the test camera in the first color space; determining a mapping of the first color space to the second color space based on the detected sets of predefinedColor spectra in the second color space and in the first color space; and applying the image to the inspection camera to inspect the vehicle component in the second color space. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 9 Such a method allows the inspection of vehicle components and is suitable for series testing due to its easily implemented and therefore cost-effective system components. This method converts RGB raw data into the standard color space using simply constructed standard color industrial cameras. A standard color industrial camera is used together with a spectrometer to determine a mapping of a first color space, e.g., RGB of the camera, to a second color space, e.g., the standard color space, using the color spectra thus acquired. According to a second aspect, the above-described object is achieved by an inspection system for determining a mapping of a first color space (e.g., R, G, B) of a inspection camera to a second color space.(for example, X, Y, Z) of a spectrometer for testing a test object, in particular a vehicle component, in the second color space, wherein the testing system comprises: an arrangement of a plurality of light sources, which is configured to generate a set of predefined color spectra; a spectrometer configured to detect the set of predefined color spectra in the second color space; a test camera configured to detect the set of predefined color spectra in the first color space; and a control computer configured to determine a mapping of the first color space to the second color space based on the detected sets of predefined color spectra in the second color space and in the first color space; and to apply the mapping to the test camera for testing the vehicle component in the second color space. Just like the method, the analogous testing system also allows the testing of vehicle components and is suitableis particularly well-suited for series testing due to its easy-to-implement and therefore cost-effective system components. The testing system converts RGB raw data into the color space standard system using simply constructed standard color industrial cameras. A standard color industrial camera is used together with a spectrometer to determine a mapping of a first color space, e.g., RGB of the camera, to a second color space, e.g., the color space standard system, using the color spectra thus acquired. The following embodiments of the method or testing system relate to the first aspect of the invention described above. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 10 According to an exemplary embodiment of the method or testing system, the first color space is a color space of a 3-channel color camera for generating three color channels (e.g., R, G, B); and the second color space is a standard viewer color space (e.g., X, Y, Z). Thus, the firstColor space can correspond to the color space of an easily procured 3-channel color camera and the second color space can correspond to the standard viewer color space (X, Y, Z), which provides advantageous perception by the human observer. According to an exemplary embodiment of the method or test system, the method or test system comprises the following step: positioning the arrangement of the plurality of light sources at a predetermined distance from the test camera; wherein the predetermined distance from the test camera corresponds to a distance from the vehicle component to be tested by the test camera. This results in the advantage that the test camera is calibrated or adjusted at the same distance from the plurality of light sources as occurs in the test system as the distance to the vehicle component. The adjustment or calibration can therefore be carried out very precisely. According to an exemplary embodiment of the method or test system, the arrangement of theA plurality of light sources are housed in an integrating sphere, which has a light exit surface from which light emerges according to the set of predefined color spectra generated by the light sources. Such an integrating sphere allows directed radiation to be converted into diffuse radiation or to collect the radiation from divergent sources. According to an exemplary embodiment of the method or test system, the integrating sphere and the spectrometer are housed in a light box; and the spectrometer is calibrated with the integrating sphere and the light exit surface of the integrating sphere. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 11 This allows a particularly compact structure to be achieved, with which a precise adjustment of the camera can be achieved. According to an exemplary embodiment of the method or test system, the light box comprises a light source driver module for controlling the arrangement of the plurality of light sources; and the generationThe set of predefined color spectra is determined based on controlling the light source driver module with a control computer. The light box can be easily controlled via the control computer. According to an exemplary embodiment of the method or test system, the mapping of the first color space to the second color space is represented by a transformation matrix T. With such a transformation matrix, a simple conversion of the first color space into the first color space and vice versa can be performed. According to an exemplary embodiment of the method or test system, the acquired set of predefined color spectra in the second color space is represented by a spectrometer matrix ^^; the acquired set of predefined color spectra in the first color space is represented by a camera matrix ^^; and the transformation matrix ^^ is determined via the matrix relationship ^^ ൌ ൫^^T ⋅ି^ ⋅ ^^൯. This provides a simple relationship for converting the first color space into the first color space and vice versa. The following embodiments of the method or inspection system relate to the second partial aspect of the invention described above. According to an exemplary embodiment of the method or inspection system, the inspection camera is a first inspection camera of a plurality of inspection cameras; and the arrangement of the plurality of light sources is a reference light source. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 12 With such a system comprising a plurality of inspection cameras, a particularly good resolution can be achieved for each camera of the camera system. According to an exemplary embodiment of the method or inspection system, the method comprises arranging the reference light source in a first position, wherein in the first position of the reference light source, the first inspection camera and the spectrometer receive light from a light exit surface of the reference light source.This offers the advantage that the first inspection camera and the spectrometer share a common measurement spot on the homogeneously emitted reference light source, so that their respective spectra can be converted into one another. According to an exemplary embodiment of the method or inspection system, the method comprises: representing the acquired set of predefined color spectra in the second color space of the spectrometer using a spectrometer matrix ^^. Pos1 with respect to the first position of the reference light source; displaying the captured set of predefined color spectra in the first color space of the first inspection camera by a first camera matrix ^^ K1 with respect to the first position of the reference light source; and determining the transformation matrix ^^ K1of the first inspection camera in relation to the first position of the reference light source via the matrix relationship ^^K1 ൌ ^^^ TPos1 ⋅ ^^K1^ ⋅ ^^^TK1 ⋅ ^^K1^െ1 . This provides a simple relationship for converting the first color space into the first color space and vice versa. According to an exemplary embodiment of the method or inspection system, the method comprises: arranging the reference light source in a second position, wherein in the second position of the reference light source a second inspection camera of the plurality of inspection cameras and the spectrometer receive light from a light exit surface of the reference light source. In this way, all positions can be gradually approached with the reference light source in order to calibrate or adjust the corresponding inspection cameras. According to an exemplary embodiment of the method or inspection system, the method comprises: displaying the recorded set of predefined color spectra in the first Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 13 Color space of the second test camera through a second camera matrix ^^. K2 with respect to the second position of the reference light source; and determining the transformation matrix ^^ K2 the second test camera with respect to the second position of the reference light source via the matrix Beziehung As already described above, a simple relationship exists for transforming the first color space into the first color space and vice versa. According to an exemplary embodiment of the method or inspection system, the method comprises: arranging the reference light source in further positions, wherein in the further positions of the reference light source, a further inspection camera of the plurality of inspection cameras and the spectrometer each receive light from a light exit surface of the reference light source; and determining the respective transformation matrices ^^ K^^of the other test cameras in relation to the respective further positions of the reference light source via the respective matrix relationship ^^ ൌ ^^^ T ⋅ ^^ ^ ⋅ ^ TPos1 K^^ ^^K^^ As already described above, this provides a simple relationship for converting the first color space into the first color space and vice versa. According to an exemplary embodiment of the method or test system, the method comprises: after arranging the reference light source in the further positions, arranging the reference light source in the first position; and displaying the acquired set of predefined color spectra in the second color space of the spectrometer using a control spectrometer matrix ^^Pos1,Control with respect to the first position of the reference light source. This offers the advantage that a comparison can be made to check whether the environment has changed during the movement of the reference light source. According to an exemplary embodiment of the method or test system, the method comprises: displaying an error if a deviation of the control spectrometer matrix ^^Pos1,Control from the spectrometer matrix ^^ Pos1exceeds a threshold value. Lisa Dräxlmaier GmbH February 7, 2025 1722023-WO-PCT 14 An error can thus be efficiently determined and displayed in order to warn the user that something has changed in the test environment. The following embodiments of the method and test system relate to the third partial aspect of the invention described above. According to an exemplary embodiment of the method or test system, the arrangement comprising the plurality of light sources, the spectrometer and the test camera are integrated in a test station and arranged in the test station in a fixed position relative to one another. With such a fixed position relative to one another, a particularly precise measurement can be carried out and thus a more precise calibration or adjustment of the components. According to an exemplary embodiment of the method or test system, a measuring point of the spectrometer lies in an image area of ​​the test camera.This ensures that the inspection camera and spectrometer are aligned to the same measurement point. According to an exemplary embodiment of the method or inspection system, the plurality of light sources comprises a first light source for generating light of a first color (R), a second light source for generating light of a second color (G), and a third light source for generating light of a third color (B); and the inspection camera is a 3-channel color camera for generating three color channels (R, G, B). Such an inspection system or method is easy to implement; the light source can be a simple RGB LED, and the camera a readily available industrial color camera.According to an exemplary embodiment of the method or inspection system, the method comprises: switching on the first light source to generate light of the first color (R); capturing a 3-channel color image in the first color space of the inspection camera and a spectroradiometer measurement in the second color space of the spectrometer with the first light source switched on; generating a camera value (^^. rot , ^^ rot , ^^ rot ) for each of the three color channels (R, G, B) of the 3-channel color camera in the first color space for the first light source; and generating a spectroradiometer value (^^ rot , ^^ rot , ^^ rot) of the corresponding color channel (R, G, B) of the 3-channel color camera in the second color space for the first light source. This allows the first color space to be easily mapped to the second color space. According to an exemplary embodiment of the method or test system, generating the camera value (^^ rot , ^^ rot , ^^ rot) for each of the three color channels (R, G, B) the following: Averaging of pixels of the image area of ​​the inspection camera that lie within the spectrometer's measurement point. By averaging the corresponding pixels, very precise, sharp camera values ​​can be generated. The spectrometer and inspection camera are directed at the same measurement point. According to an exemplary embodiment of the method or inspection system, the method comprises: after switching on the first light source, successively switching on the second light source to generate light of the second color (G) and the third light source to generate light of the third color (B); and correspondingly capturing 3-channel color images ^^ grün , ^^ grün , ^^ grün , ^^ blau , ^^ blau , ^^ blau and spectroradiometer measurements ^^ grün , ^^ grün , ^^ grün, ^^ blau , ^^ blau , ^^ blaufor the second light source and the third light source. This allows precise measurements of the test object to be determined via the plurality of cameras. According to an exemplary embodiment of the method or test system, the method comprises: determining a spectrometer matrix ^^ RGB-LED1 and a camera matrix ^^ RGB-LED1 for the first light source based on the acquired 3-channel color images and the acquired spectroradiometer measurements using the following relationships: Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 16 These matrices make it easy to accurately map the first color space into the second color space and vice versa. According to an exemplary embodiment of the method or test system, the method comprises: determining the mapping of the first color space to the second color space for the first light source using a transformation matrix ^^ RGB-LED1 for the first light source via the matrix relationship Such a transformation matrix is ​​easy to determine. This disclosure describes color cameras, luminance cameras, color luminance cameras, and hyperspectral cameras. Color cameras or color luminance cameras are imaging measurement systems calibrated to a color space. Using color filters (usually rotating), several images filtered in different colors are captured. Therefore, these systems are relatively slow, and the individual images are captured sequentially. Since luminance cameras are calibrated with standardized light sources (e.g., standard illuminant A, D50, D65, etc.), a measurement error can occur despite calibration for spectra that are to be measured individually. Hyperspectral cameras are imaging measurement systems that have far more than three color channels and thus provide more detailed spectral information than simple RGB color cameras. The spatial resolution of hyperspectral cameras is generally lower than that of RGB color cameras.The spectral resolution of hyperspectral cameras is many times lower than that of spectrometers. Therefore, an error always occurs when converting the spectral information to standard brightness or color values ​​(e.g. Lu'v' color space, luminance ^^ with color coordinates ^^′ and ^^'). A simple variant of the hyperspectral camera is the multispectral camera. This has significantly fewer color channels per pixel than the "hyper" variant. Color calculation errors are even more pronounced here. This disclosure describes spectrometers and spectroradiometers. Spectrometers and spectroradiometers are calibrated point-measuring measuring systems. These offer the highest resolution in the wavelength range. All brightness and color values ​​are summed to a single value at this measuring point. No brightness or Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 17 Color information can be realized without a complex scanning process (e.g., mirror deflection, mechanical process, etc.). However, one is free to calculate brightness and color information. Brief description of the figures The invention is described in more detail below with reference to exemplary embodiments and the figures. They show: Fig. 1 a schematic representation of a method 100 according to the invention for determining a mapping of a first color space (R, G, B) of a test camera (K) onto a second color space (X, Y, Z) of a spectrometer for testing a test object, in particular a vehicle component; Fig. 2 a graphic representation 200 of the spectral sensitivity of an exemplary test camera; Fig. 3 a graphic representation 300 of the spectral value functions according to the CIE 1931 standard; Fig.4 shows a schematic representation of an exemplary test system 400 with a first area 410 for transformation matrix generation and a second area 420 for test object measurement according to the first partial aspect of the invention; Fig. 5 shows a plan view of an exemplary test system 500 with fixedly arranged cameras K1 to K8, a fixed spectrometer S and a calibration light source L movable on an xy rail system according to the second partial aspect of the invention; Fig. 6 shows a side view of the test system 500 from Fig. 5 with spectrometer S and camera K1 with calibration light source L at position 1 with overlapping measurement range and differently controlled light colors red, green, blue; Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 18 Fig. 7 shows a plan view of the test system 500 from Fig. 5 with calibration light source L at position 1 with travel path 701 over all cameras; and Fig.8 shows an exemplary set 800 of test images (red, green, blue) 801, 802, 803 of an RGB LED 812 behind a diffuse lens with region 813 for “camera-to-spectrometer” matching according to the third aspect of the invention. The figures are merely schematic representations and are intended to explain the invention only. Like or similar elements are designated by the same reference numerals throughout. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the concept of the present invention. The following detailed description is not to be taken in a limiting sense.Further, it should be understood that the features of the various embodiments described herein may be combined with one another unless specifically stated otherwise. The aspects and embodiments are described with reference to the drawings, wherein like reference numerals generally refer to like elements. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects of the invention. However, it may be apparent to one skilled in the art that one or more aspects or embodiments may be practiced with a lesser level of specific detail. In other instances, well-known structures and elements are shown in schematic form to facilitate describing one or more aspects or embodiments.It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the concept of the present invention. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 19 Fig. 1 shows a schematic representation of a method 100 according to the invention for determining a mapping of a first color space (R, G, B) of a test camera (K) onto a second color space (X, Y, Z) of a spectrometer for testing a test object, in particular a vehicle component.The method 100 comprises the following steps: controlling 101 an arrangement of a plurality of light sources to generate a set of predefined color spectra; capturing 102 the set of predefined color spectra with a spectrometer (S) in the second color space (X, Y, Z); capturing 103 the set of predefined color spectra with the inspection camera (K) in the first color space (R, G, B); determining 104 a mapping of the first color space to the second color space based on the captured sets of predefined color spectra in the second color space (X, Y, Z) and in the first color space (R, G, B); and applying 105 the mapping to the inspection camera (K) to inspect the vehicle component (P) in the second color space (X, Y, Z). The invention described here comprises three sub-aspects.While Figure 1 as well as Figures 2 and 3 illustrate the general concept of the invention, Figure 4 shows the first partial aspect of the invention, Figures 5 to 7 the second partial aspect of the invention, and Figure 8 the third partial aspect of the invention. All three partial aspects are based on the general illustration in Figure 1. The first partial aspect is described in more detail below with reference to Figure 1. The first color space can be a color space of a 3-channel color camera for generating three color channels (R, G, B). The second color space can be a standard viewer color space (X, Y, Z), as described in more detail with reference to Figures 2 to 4. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 20 The method 100 can comprise the following step: positioning the arrangement of the plurality of light sources 405 at a predetermined distance from the inspection camera K, 402.The predetermined distance to the test camera K, 402 can, for example, correspond to a distance to the vehicle component P, 401 to be tested by the test camera K, as described in more detail with reference to Figure 4. The arrangement of the plurality of light sources 405 can be accommodated in an integrating sphere I, 404, which has a light exit surface L, 406, from which light emerges according to the set of predefined color spectra generated by the light sources, as described in more detail with reference to Figure 4. The integrating sphere I, 404 and the spectrometer S, 403 can, for example, be accommodated in a light box 409, as described in more detail with reference to Figure 4. The spectrometer S, 403 can be calibrated with the integrating sphere I, 404 and the light exit surface L of the integrating sphere I, 404, as described in more detail with reference to Figure 4. The light box 409 may include a light source driver module T, 407 for controlling the arrangement of the plurality of light sources 405, as described in more detail with reference to Figure 4.The generation of the set of predefined color spectra can, for example, be based on controlling the light source driver module T, 407 with a control computer PC, 408, as described in more detail with reference to Figure 4. The mapping of the first color space to the second color space can be represented by a transformation matrix T, as described in more detail with reference to Figure 4. The acquired set of predefined color spectra in the second color space (X, Y, Z) can be represented by a spectrometer matrix S, as described in more detail with reference to Figure 4. The acquired set of predefined color spectra in the first color space (R, G, B) can be represented by a camera matrix ^^, as described in more detail with reference to Figure 4. The transformation matrix ^^ can be determined using the matrix relationship ^^ ൌ ൫^^T ⋅ି^. ⋅ ^^൯determine, as described in more detail with reference to Figure 4. The second partial aspect is described in more detail below with reference to Figure 1. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 21 The test camera K, 402 can be a first test camera K1 of a plurality of test cameras K1, K2, K3, K4, K5, K6, K7, K8, as described in more detail with reference to Figures 5, 6 and 7. The arrangement of the plurality of light sources can be a reference light source L, 510, as described in more detail with reference to Figures 5, 6 and 7. The method 100 may further comprise the following step: arranging the reference light source L, 510 in a first position Pos1, 501, as described in more detail with reference to Figures 5, 6 and 7, wherein in the first position 501 of the reference light source L, 510, the first inspection camera K1 and the spectrometer S, 403 receive light from a light exit surface of the reference light source L, 510.The method 100 may comprise the following steps: Representing the acquired set of predefined color spectra in the second color space (X, Y, Z) of the spectrometer S, 403 by a spectrometer matrix ^^. Pos1 with respect to the first position Pos1, 501 of the reference light source L, 510; displaying the captured set of predefined color spectra in the first color space (R, G, B) of the first test camera K1 by a first camera matrix ^^ K1 with respect to the first position Pos1, 501 of the reference light source L, 510; and determining the transformation matrix ^^ K1 of the first test camera K1 in relation to the first position Pos1,501 of the reference light source L, 510 via the matrix relationship ^^K1 ൌ ^^^ TPos1 ⋅ ^^K1^ ⋅ as described in more detail with reference to Figures 5, 6, and 7. The method 100 may comprise the following step: arranging the reference light source L, 510 in a second position Pos2, 502, wherein in the second position 502 of the reference light source L, 510, a second inspection camera K2 of the plurality of inspection cameras K1, K2, K3, K4, K5, K6, K7, K8 and the spectrometer S, 403 receive light from a light exit surface of the reference light source L, 510, as described in more detail with reference to Figures 5, 6, and 7. The method 100 may comprise the following steps: displaying the captured set of predefined color spectra in the first color space (R, G, B) of the second inspection camera K2 by a second camera matrix ^^ K2 with respect to the second position Pos2, 502 of the reference light source L; and determining the transformation matrix ^^ K2of the second test camera K2 in relation to the second position Pos2, 502 of the reference light source L, 510 via the matrix Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 22Relationship ^^ ൌ ^ TK2 ^^Pos1 ⋅ as described in more detail with reference to Figures 5, 6, and 7. The method 100 may comprise the following steps: arranging the reference light source L, 510 in further positions Pos3-Pos8, 503-508, wherein in the further positions 503-508 of the reference light source L, 510, a further inspection camera K3, K4, K5, K6, K7, K8 of the plurality of inspection cameras K1, K2, K3, K4, K5, K6, K7, K8 and the spectrometer S, 403 receive light from a light exit surface of the reference light source L, 510; and determining the respective transformation matrices ^^ K^^ the other test cameras ^^ K^^ in relation to the respective further positions Pos3, Pos4, Pos5, Pos6, Pos7, Pos8 of the reference light source L, 510 via the respective matrix relationship ^^K^^ ൌ ^^^ TPos1 ⋅ ^^K^^^ ⋅ ^^^T K^^ as described in more detail with reference to Figures 5, 6, and 7. The method 100 may further comprise the following steps: after arranging the reference light source L, 510 in the further positions Pos3, Pos4, Pos5, Pos6, Pos7, Pos8, arranging the reference light source L, 510 in the first position Pos1, 501; and representing the acquired set of predefined color spectra in the second color space (X, Y, Z) of the spectrometer S, 403 by a control spectrometer matrix ^^Pos1,Control with respect to the first position Pos1, 501 of the reference light source L, 510, as described in more detail with reference to Figures 5, 6, and 7. The method 100 may further comprise the following step: displaying an error if a deviation of the control spectrometer matrix ^^Pos1,Control from the spectrometer matrix ^^ Pos1exceeds a threshold value, as described in more detail with reference to Figures 5, 6 and 7. The third partial aspect is described in more detail below with reference to Figure 1. The arrangement comprising the plurality of light sources, the spectrometer S, 403 and the inspection camera K can be integrated in a test station and arranged in a fixed position relative to one another in the test station, as described in more detail with reference to Figure 8. A measuring point 813 of the spectrometer S, 403 can, for example, lie in an image area 811 of the inspection camera K, as described in more detail with reference to Figure 8. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 23 The plurality of light sources can comprise a first light source for generating light of a first color (R), a second light source for generating light of a second color (G) and a third light source for generating light of a third color (B), as described in more detail with reference to Figure 8.The inspection camera K can be a 3-channel color image camera for generating three color channels (R, G, B), as described in more detail with reference to Figure 8. The method 100 can comprise the following steps: switching on the first light source to generate light of the first color (R); capturing a 3-channel color image in the first color space of the inspection camera K and a spectroradiometer measurement in the second color space (X, Y, Z) of the spectrometer S, 403 with the first light source switched on; generating a camera value (^^. rot , ^^ rot , ^^ rot ) for each of the three color channels (R, G, B) of the 3-channel color camera in the first color space (R, G, B) for the first light source; and generating a spectroradiometer value (^^ rot , ^^ rot , ^^ rot ) of the corresponding color channel (R, G, B) of the 3-channel color camera in the second color space (X, Y, Z) for the first light source, as described in more detail in Figure 8. The generation of the camera value (^^ rot , ^^rot , ^^ rot ) for each of the three color channels (R, G, B) may comprise the following: averaging pixels of the image area of ​​the inspection camera K that lie within the measurement point 813 of the spectrometer S, 403, as described in more detail with reference to Figure 8. The method 100 may comprise the following steps: after switching on the first light source, successively switching on the second light source to generate light of the second color (G) and the third light source to generate light of the third color (B); and correspondingly capturing 3-channel color images ^^ grün , ^^ grün , ^^ grün , ^^ blau , ^^ blau , ^^ blau and spectroradiometer measurements ^^ grün , ^^ grün , ^^ grün ,^^ blau , ^^ blau , ^^ ^^^^^^^^ for the second light source and the third light source, as described in more detail in Figure 8. The method 100 may include the following step: determining a spectrometer matrix ^^ RGB-LED1and a camera matrix ^^ RGB-LED1 for the first light source based on the acquired 3-channel color images and the acquired spectroradiometer measurements via the following relationships, as described in more detail in Figure 8: Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 24 The method 100 may comprise the following step: determining the mapping of the first color space to the second color space for the first light source via a transformation matrix ^^RGB-LED1 for the first light source via the matrix relationship ^^ ൌ ൫^^^ ⋅ as described in more detail with reference to Figure 8. The method 100 described above with the three described sub-aspects can be implemented in a testing system. Such a testing system for determining a mapping of a first color space (R, G, B) of a testing camera K onto a second color space (X, Y, Z) of a spectrometer S for testing a vehicle component P in the second color space (X, Y, Z) comprises the following components: an arrangement of a plurality of light sources, which is designed to generate a set of predefined color spectra; a spectrometer S, which is designed to detect the set of predefined color spectra in the second color space (X, Y, Z); a testing camera K, which is designed to detect the set of predefined color spectra in the first color space (R, G, B); and a control computer (PC).The control computer is configured to determine a mapping of the first color space to the second color space based on the acquired sets of predefined color spectra in the second color space (X, Y, Z) and in the first color space (R, G, B); and to apply the mapping to the inspection camera (K) for inspecting the vehicle component (P) in the second color space (X, Y, Z). Fig. 2 shows a graphical representation 200 of the spectral sensitivity of an exemplary inspection camera. A color (industrial) camera is an imaging system with typically three intensity values ​​per pixel. These three intensity values ​​are determined by subpixels, each of which has a different color filter in the beam path in front of the subpixel. There are 25 different technical systems for how this can be accomplished (for example, using a prism camera with three spectral bands, multilayer image sensors, Bayer sensors).As an example, the spectral sensitivity of a color sensor is shown here. The output intensity ^^, ^^, ^^ for each color channel of the camera is determined via the integral of the respective spectral distribution ^ത^cam. ^ ^^ ^ , ^ത^cam ^ ^^ ^ , ത ^^cam ^ ^^ ^ of the curves shown here in the red 201, green 202, and blue 203 ranges. These spectral distributions are modified accordingly by additional optical elements in the beam path, such as pre-filters (e.g., neutral density gray filters), lenses, etc. In the following, ^^, ^^, ^^ are always used for camera intensity values ​​of a spectrum. Fig. 3 shows a graphical representation 300 of the spectral value functions according to the CIE 1931 standard. The spectral value functions defined according to CIE 1931 ^ത^ ^ ^^ ^ , ^ത^ ^ ^^ ^ , ^ത^ ^^^ ^ After integration over the wavelength, they yield the standard observer color space with ^^, ^^, ^^ as the corresponding perceived tristimulus color intensity. ^^ corresponds to human brightness sensitivity in daylight. A color perception can be represented by converting the tristimulus values ​​accordingly to the CIE standard chromaticity diagram (CIE 1931): ^^ ^ ^ ൌ ^^ ^ ^^ ^ ^^^^ ^ ^ ൌ ^^ ^ ^^ ^ ^^or converted into the CIELUV color space (CIE 1976)ᇱ 4^^ ^ ^ ൌ ^^ ^ 15^^ ^ 3^^ ᇱ 9^^ ^ ^ ൌ^^ ^ 15^^ ^ 3^^ Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 26 This represents a linear relationship for color differences between the geometric representation and the perception. The camera values ​​^^, ^^, ^^ are obtained as the basis for the component measurement, which are then converted into ^^, ^^, ^^ by linear transformation in order to then convert to the CIELUV color space. The subsequent component assessment should be carried out in CIELUV in order to technically assess color deviations with equal distances in the same way as via human perception. Fig. 4 shows a schematic representation of an exemplary testing system 400 with a first area 410 for transformation matrix generation and a second area 420 for test object measurement according to the first partial aspect of the invention. In order to perform the linear transformations from ^^, ^^, ^^ to ^^, ^^, ^^, as described above for Figure 3, the camera- and test object-specific transformation matrix ^^ must be found.For this purpose, a set of selected spectra is measured using the inspection camera and a spectrometer. It is assumed that the spectrum to be measured later (here, narrowband LED spectra in the VIS range) closely resembles the set of selected spectra. For this purpose, the inspection system 400 shown in Figure 4 is used, with the setup shown here for transformation matrix acquisition (range 1, 410) and for test piece measurement (range 2, 420). The setup for obtaining the transformation matrix ^^ (area 1, 410) is divided into three main parts: a measurement PC (PC, 408), a test camera (K, 402), and a light box 409, which is divided into a spectrometer (S, 403), an LED driver module (T, 407), and several LEDs (LEDs, 405) located in an integrating sphere (I, 404). The spectrometer (S, 403) is calibrated with the integrating sphere (I, 404) and its homogeneous, diffuse light exit surface (L, 406).The light box is positioned so that it can be moved within the area 1, 410 and is thus also capable of providing additional inspection cameras with transformation matrices. For the sake of simplicity, only the operation of one inspection camera will be considered below. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 27 The individually adjustable LEDs (LEDs, 405) are controlled by the measuring PC (PC, 408) via the driver module (T, 407), so that a previously defined set of ^^ spectra is generated. These spectra are measured with the spectrometer (S, 403) and stored as ^^. ^^ , ^^ ^^ , ^^ ^^ This results in a spectrometer matrix ^^. Accordingly, the ^^-, ^^-, ^^-values ​​of the spectra are determined with the camera (K, 402) at the light exit surface (L, 406). This results in a camera matrix ^^. ^^ ^ ^^ ^ ^^ ^ ^^ ^ ^^ ^ ^^ ^ ^^ ൌ ^ ⋮ ⋮ ⋮ ൩ , ^^ ൌ ^ ⋮ ⋮ ⋮൩ ^^^ ^^ ^ ^^ ^ ^^ ^ ^^ ^ ^^ ^ According to the linear approach ^^ ൌ ^^ ⋅ ^^the transformation matrix ^^ is During further testing, the test camera (K, 402) is operated independently. This means that the light box 409 is not required during testing. In this specific case, the test camera (K, 402) is moved from the light box 409 to the test cell in area 2, 420, in which the test piece (P, 401) is located. The test piece (P, 401) is at the same distance from the test camera (K, 402) as the exit surface (L, 406) of the light box 409. The measuring PC (PC, 408) controls the test piece (P, 401) and the test camera (K, 402), which now have the corresponding ^^ ^^ -, ^^ ^^ -, ^^ ^^ - provides test values ​​in the previously defined camera image area. Using the previously obtained transformation matrix ^^, these values ​​are converted into test tristimulus color values ​​^^ ^^ , ^^ ^^ , ^^ ^^converted. ^^ ^^ ൌ ^^^ ^^ , ^^ ^^ , ^^ ^^ ^ ^^ ^^ ൌ ^^ ⋅ ^^ ^^ ⇒ ^^ ^^ ൌ ^^^ ^^ , ^^ ^^ , ^^ ^^^ In this way, further calculation into the CIELUV color space can be implemented as shown above. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 28 To recalculate and check the transformation matrix ^^, the inspection camera (K, 402) is moved back into the area 1, 410 at a specified time interval. In this way, the ^^-, ^^-, ^^- camera values ​​can be adjusted again using the specified spectra of the LEDs of the light box 409 and the spectrometer (S, 403). Fig. 5 shows a plan view of an exemplary inspection system 500 with fixedly arranged cameras K1 to K8, fixed spectrometer S and a calibration light source L movable on an xy rail system according to the second partial aspect of the invention. In order to perform the linear transformations from ^^, ^^, ^^ to ^^, ^^, ^^ shown in Figure 3, the camera-specific transformation matrix ^^ must be found.This requires at least three "test colors," each falling within the camera ^^, ^^, ^^ spectral ranges and the ^^, ^^, ^^ spectral ranges. This applies when measuring an RGB LED. For other light types (white light, etc.), an accuracy analysis of the measuring system should be carried out beforehand. In order to optimally calibrate cameras K1 to K8 to the product to be tested, a light source ("calibration light source 510") was developed that incorporates identical RGB LEDs as the product to be tested. Slight measurement fluctuations resulting from color binning of the product RGB LEDs are tolerated because they have less impact than when calibrating the camera with a light type that is spectrally different from the product (e.g., standard light A, D65, etc.). The light source 510 is designed so that it can be controlled with the same control module and the same digital commands as the components to be tested. This enables extremely simple system integration.In addition, the "calibration light source" 510 is illuminated as homogeneously as possible to compensate for positioning errors between the camera positions 501 to 508 or the spectrometer S, 403. The "calibration light source" 510 is located on an xy-rail system and can be moved between the individual cameras K1, K2, K3, K4, K5, K6, K7, K8 to be calibrated. Figure 5 shows an exemplary inspection system 500 with an exemplary number of eight cameras K1, K2, K3, K4, K5, K6, K7, K8. It is understood that any other number of cameras can also be used here. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 29 Fig. 6 shows a side view of the inspection system 500 from Figure 5 with spectrometer S and camera K1 with calibration light source L at position 1 with an overlapping measurement range and variously controlled light colors (red, green, and blue). The first step of camera calibration takes place at position 1, 501.If the "calibration light source" 510 is located at this point, the spectrometer S, 403, and camera 1 (K1) share a common measurement spot on the homogeneously emitted "calibration light source" 510, as shown in Figure 6. The "calibration light source" 510 is now controlled so that it emits defined colored light. Schematically shown here in the colors red (201), green (202), and blue (203). For each of these colors, a measurement data set from the spectrometer with ^^ results. Pos1 and the camera K1 with ^^ K1 . These are sufficient to perform a conversion for each camera pixel from camera ^^^^^^- values ​​to ^^^^^^ -values. Following the linear approach ^^ ൌ ^^ ⋅ ^^, a conversion matrix ^^ K1 ("^^^^^^-to-^^^^^^") for camera K1. This transformation matrix ^^ results in Since the spectrometer 403 is permanently installed, like the cameras, measurement data can only be generated with the spectrometer at one location (position 1, 501). This only happens at position 1, 501. Therefore, it is necessary to move the "calibration light source" 510 into the respective field of view of each camera K1 to K8, as shown in more detail in Figure 7. Fig. 7 shows a top view of the test system 500 from Figure 5 with calibration light source L at position 1 with travel path 701 across all cameras. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 30 By proving that the radiation of the "calibration light source" 510 is constant over time, it is assumed that the controlled light of the "calibration light source" 510 changes infinitesimally slightly, while this light is measured with the cameras at the other camera positions. The same spectrometer data set is always used to calibrate the following cameras K2- K8 ^^ Pos1as with camera K1 at position 1, 501. The data sets of the following cameras are analogous to camera K1 with ^^ K2 , ^^ K3 , … ^^ K8 . Likewise, the conversion matrices for each camera K2 to K8 are Each camera calibration is checked for accuracy with a verification measurement of the controlled light colors. Once all cameras have been calibrated, the "calibration light source" 510 is moved back to position 1, 501, and then measured again with the spectrometer S, 403. This results in the data set ^^Pos1,Control. A comparison for data deviations ^^ Pos1 and ^^Pos1,Control is implemented as a step to validate the correct camera alignment of all cameras. If this is successful, the cameras can be used. The eight conversion matrices ^^ K1…8are applied to the recorded ^^^^^^ camera image of the respective camera during each component test. Each of the cameras can now display images in the ^^, ^^, ^^ color space, which can then be transferred to the CIELUV color space (CIE 1976) in order to be able to carry out not only comparative tests on components, but also absolute measurements in a defined color space. Fig. 8 shows an exemplary set 800 of test images (red, green, blue) 801, 802, 803 of an RGB LED 812 behind a diffuse scattering screen with region 813 for "camera-to-spectrometer" comparison according to the third partial aspect of the invention. In order to be able to carry out the linear transformations from ^^, ^^, ^^ to ^^, ^^, ^^, as shown in Figure 3, the camera- and test object-specific transformation matrix ^^ must be found. For this purpose at least three “test colours” are required, each of which is inserted into the camera- ^^, ^^, Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 31 ^^ spectral ranges and fall into the ^^, ^^, ^^ spectral ranges. This applies when measuring an RGB LED. For other light types (e.g., white light, etc.), an accuracy analysis of the measurement system should be carried out beforehand. The status light of the Gen6 charging socket must be calibrated for brightness and color. Since a brightness and color calibrating status light uses RGB LEDs, each of which must be controlled and measured in the individual color channels, this is a suitable example for explaining color and brightness calibration for color cameras during component testing. The three test colors required for camera calibration arise from the calibration of the status light, since the RGB LEDs used (three in this case) must be calibrated here.The RGB LED calibration routine is as follows: - Switch on the red LED with a known current, measure the color and brightness, - Repeat with the green LED, - Repeat with the blue LED. - Summarize the measured values ​​and calculate them in a given calibration matrix. - Write the calculated calibration data to the LED controller. The LED controller can now convert given color and brightness values ​​into a corresponding current supply for the individual LEDs (red, green, blue) so that the RGB LED shines in the desired / controlled color and brightness. - Validation test with color and brightness control of the RGB LED. The following RGB LED calibration steps are used for camera calibration: In the RGB LED calibration routine, the red LED of the RGB LED 812 is controlled first. A camera image 811 and a spectroradiometer measurement are recorded simultaneously.At a point 813 (see illustration in Figure 8) in the image 811, the spectroradiometer measurement point is superimposed on the camera image 811. All ^^, ^^, ^^ color values ​​of the pixels within this area 813 are averaged for each color channel 801, 802, 803, resulting in one camera value for each ^^. rot , ^^ rot and ^^ rot for the red LED. The corresponding spectroradiometer values ​​are ^^ rot , ^^ rot and ^^ rot Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 32 The same procedure is performed for the other two primary LEDs (green and blue). This results in a spectrometer matrix ^^ and a camera matrix ^^ for the first RGB LED: This is sufficient to perform a conversion for each camera pixel from camera ^^^^^^ values ​​to ^^^^^^ values. For this purpose, a conversion matrix ^^ is created for this one RGB LED with its three image recordings. RGB-LED1(“^^^^^^-to-^^^^^^”). According to the linear approach ^^ ൌ ^^ ⋅ ^^the transformation matrix ^^ is The resulting transformation matrix ^^ RGB-LED1 is only valid for the RGB LED measured here. The three images of the RGB LED are now displayed with ^^ RGB-LED1converted and you get three camera ^^^^^^ images from the three camera ^^^^^^ images - one ^^^^^^ image for the controlled red LED, one ^^^^^^ image for the controlled green LED and one ^^^^^^ image for the controlled blue LED. No further images need to be taken; instead you use the ones that have already been taken and simply convert them to a different color space. The camera images were previously only used for the "camera values ​​to spectroradiometer values" comparison. Now it is possible to select each measurement range in the three ^^^^^^ images for the RGB LED calibration, which is necessary to determine optimal measurement values ​​for the RGB LED calibration. For example, tracking of an evaluation region can now be implemented in the image, enabling repeatable measurements even with fluctuating component positions. This evaluation region then provides ^^^^^^ values ​​for the RGB LED calibration.This makes it possible to have a separate transformation matrix for each of the three RGB LEDs ^^. RGB- LED1 , ^^ RGB-LED2 and ^^ RGB-LED3 and apply it to the three respective camera images. This results in three images (red, green, blue LED) for the first RGB LED, converted using the transformation matrix. RGB-LED1 , three images with the transformation matrix ^^ RGB-LED2 , and three images with the transformation matrix ^^ RGB-LED3, which provide more precise measurement data than a general conversion of all nine images using a single transformation matrix. This saves enormous effort in positioning or tracking the spectroradiometer to the same measurement position every time and can be greatly simplified using image analysis algorithms. With camera analysis and camera-spectroradiometer alignment, one achieves almost the same accuracy as with a spectroradiometer measurement alone. However, one is position-independent and free in the subsequent analysis. Without camera support, the spectroradiometer measurement spot is very sensitive to changes in the component's position and can therefore produce correspondingly fluctuating measurement values ​​for the RGB LED calibration.

[0002] Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 34 LIST OF REFERENCE SYMBOLS 100 Method for determining a mapping of a first color space to a second color space 101 Control 102 Acquisition in second color space 103 Acquisition in first color space 104 Determination 105 Application 200 Representation of the spectral sensitivity 201 Intensity of the color channel R (red) or color channel R 202 Intensity of the color channel G (green) or color channel G 203 Intensity of the color channel B (blue) or color channel B 300 Representation of the CIE 1931 spectral value functions 400 Test system with first area 410 for transformation matrix generation and second area 420 for test piece measurement 410 first area for transformation matrix generation 420 second area for Test object measurement 401 Test object P or vehicle component 402 Test camera K 403 Spectrometer S or spectroradiometer 404 Integrating sphere I 405 Light sources or LEDs 406 Light exit surface L of the Integrating sphere I 407 Driver module T orLED driver module 408 Control computer or PC 409 Light box 500 Test system with fixed cameras K1 to K8, fixed spectrometer S and a calibration light source L that can be moved on an xy rail system Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 35 501-508 fixed positions 1 to 8 510 Light source L or calibration light source or reference light source 701 Travel path of the calibration light source L 800 Set of test images 801 R-image or test image in red 802 G-image or test image in green 803 B-image or test image in blue 811 Camera image 812 Image area of ​​the LED in the camera image 813 Adjustment region for the “camera-to-spectrometer” adjustment.

Claims

Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 1 PATENT CLAIMS 1. Method (100) for determining an image of a first color space (R, G, B) of a test camera (K) onto a second color space (X, Y, Z) of a spectrometer (S) for testing a vehicle component (P) in the second color space (X, Y, Z), the method (100) comprising the following steps: controlling (101) an arrangement of a plurality of light sources to generate a set of predefined color spectra; detecting (102) the set of predefined color spectra with a spectrometer (S) in the second color space (X, Y, Z); detecting (103) the set of predefined color spectra with the test camera (K) in the first color space (R, G, B); Determining (104) a mapping of the first color space to the second color space based on the detected sets of predefined color spectra in the second color space (X, Y, Z) and in the first color space (R, G, B);and applying (105) the image to the inspection camera (K) for inspecting the vehicle component (P) in the second color space (X, Y, Z).

2. The method (100) according to claim 1, wherein the first color space is a color space of a 3-channel color image camera for generating three color channels (R, G, B); and wherein the second color space is a standard viewer color space (X, Y, Z).

3. The method (100) according to claim 1 or 2, comprising: positioning the arrangement of the plurality of light sources (405) at a predetermined distance from the inspection camera (K, 402);wherein the predetermined distance to the inspection camera (K, 402) corresponds to a distance to the vehicle component (P, 401) to be inspected by the inspection camera (K).

4. The method (100) according to any one of the preceding claims, wherein the arrangement of the plurality of light sources (405) is housed in an integrating sphere (I, 404) having a light exit surface (L, 406) from which light exits according to the set of predefined color spectra generated by the light sources. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 2 5. The method according to claim 4, wherein the integrating sphere (I, 404) and the spectrometer (S, 403) are accommodated in a light box (409); and wherein the spectrometer (S, 403) is calibrated with the integrating sphere (I, 404) and the light exit surface (L) of the integrating sphere (I, 404).

6. The method according to claim 5, wherein the light box (409) comprises a light source driver module (T, 407) for controlling the arrangement of the plurality of light sources (405); and wherein the generation of the set of predefined color spectra takes place based on control of the light source driver module (T, 407) with a control computer (PC, 408).

7. The method (100) according to any one of the preceding claims, wherein the mapping of the first color space to the second color space is represented by a transformation matrix ^^. 8.The method (100) of claim 7, wherein the detected set of predefined color spectra in the second color space (X, Y, Z) is represented by a spectrometer matrix ^^; wherein the detected set of predefined color spectra in the first color space (R, G, B) is represented by a camera matrix ^^; and wherein the transformation matrix ^^ is determined via the matrix relationship ^^ ൌ ൫^^T ⋅ ^^൯ ⋅൫^^T ⋅ ^^൯ି^.

9. Test system (400, 500) for determining a mapping of a first color space (R, G, B) of a test camera (K) onto a second color space (X, Y, Z) of a spectrometer (S) for testing a vehicle component (P) in the second color space (X, Y, Z), wherein the test system (200) comprises: an arrangement of a plurality of light sources, which is designed to generate a set of predefined color spectra; a spectrometer (S) which is designed to detect the set of predefined color spectra in the second color space (X, Y, Z);. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 3 a test camera (K) configured to capture the set of predefined color spectra in the first color space (R, G, B); and a control computer (PC) configured to determine a mapping of the first color space to the second color space based on the captured sets of predefined color spectra in the second color space (X, Y, Z) and in the first color space (R, G, B); and to apply the mapping to the test camera (K) for testing the vehicle component (P) in the second color space (X, Y, Z).

10. The method (100) according to claim 1, wherein the test camera (K, 402) is a first test camera (K1) of a plurality of test cameras (K1, K2, K3, K4, K5, K6, K7, K8); and wherein the arrangement of the plurality of light sources is a reference light source (L, 510). 11.The method (100) according to claim 10, comprising: arranging the reference light source (L, 510) in a first position (Pos1, 501), wherein in the first position (501) of the reference light source (L, 510), the first inspection camera (K1) and the spectrometer (S, 403) receive light from a light exit surface of the reference light source (L, 510).

12. The method (100) according to claim 11, comprising: representing the acquired set of predefined color spectra in the second color space (X, Y, Z) of the spectrometer (S) by a spectrometer matrix ^^. Pos1 with respect to the first position (Pos1, 501) of the reference light source (L, 510); displaying the captured set of predefined color spectra in the first color space (R, G, B) of the first test camera (K1) by a first camera matrix ^^ K1 with respect to the first position (Pos1, 501) of the reference light source (L, 510); and determining the transformation matrix ^^ K1of the first test camera (K1) in relation to the first position (Pos1, 501) of the reference light source (L, 510) via the matrix relationship 13. The method (100) according to claim 12, comprising: arranging the reference light source (L, 510) in a second position (Pos2, 502), wherein in the second position (502) of the reference light source (L, 510) a second inspection camera Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 4 (K2) of the plurality of inspection cameras (K1, K2, K3, K4, K5, K6, K7, K8) and the spectrometer (S, 403) receive light from a light exit surface of the reference light source (L, 510).

14. The method (100) according to claim 13, comprising: displaying the acquired set of predefined color spectra in the first color space (R, G, B) of the second inspection camera (K2) by a second camera matrix ^^ K2 with respect to the second position (Pos2, 502) of the reference light source (L); and determining the transformation matrix ^^ K2the second test camera (K2) with respect to the second position (Pos2, 502) of the reference light source (L, 510) via the matrix relationship 15. The method (100) according to claim 14, comprising: arranging the reference light source (L, 510) in further positions (Pos3-Pos8, 503-508), wherein in the further positions (503-508) of the reference light source (L, 510), a further test camera (K3, K4, K5, K6, K7, K8) of the plurality of test cameras (K1, K2, K3, K4, K5, K6, K7, K8) and the spectrometer (S, 403) receive light from a light exit surface of the reference light source (L, 510); and determining the respective transformation matrices ^^ Ki the other test cameras (K i ) in relation to the respective further positions (Pos3, Pos4, Pos5, Pos6, Pos7, Pos8) of the reference light source (L) via the respective matrix relationship ^^K^^ ൌ ^^^ TPos1 ⋅ ^^K^^^ ⋅ 16. The method (100) according to claim 15, comprising: after arranging the reference light source (L, 510) in the further positions (Pos3, Pos4, Pos5, Pos6, Pos7, Pos8), arranging the reference light source (L, 510) in the first position (Pos1, 501); and representing the acquired set of predefined color spectra in the second color space (X, Y, Z) of the spectrometer (S) by a control spectrometer matrix ^^Pos1,Control with respect to the first position (Pos1, 501) of the reference light source (L, 510).

17. The method (100) according to claim 16, comprising: displaying an error if a deviation of the control spectrometer matrix ^^Pos1,Control from the spectrometer matrix ^^ Pos1 exceeds a threshold. Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 5 18. The method (100) according to claim 1, wherein the arrangement of the plurality of light sources, the spectrometer (S), and the inspection camera (K) are integrated in a testing station and are arranged in a fixed position relative to one another in the testing station.

19. The method (100) according to claim 18, wherein a measuring point (813) of the spectrometer (S) lies in an image area (811) of the inspection camera (K).

20. The method (100) according to claim 19, wherein the plurality of light sources comprises a first light source for generating light of a first color (R), a second light source for generating light of a second color (G), and a third light source for generating light of a third color (B); and wherein the inspection camera (K) is a 3-channel color image camera for generating three color channels (R, G, B). 21.Method (100) according to claim 20, comprising: switching on the first light source to generate light of the first color (R); capturing a 3-channel color image in the first color space of the inspection camera (K) and a spectroradiometer measurement in the second color space (X, Y, Z) of the spectrometer (S) with the first light source switched on; generating a camera value (^^. rot , ^^ rot , ^^ rot ) for each of the three color channels (R, G, B) of the 3-channel color camera in the first color space (R, G, B) for the first light source; and generating a spectroradiometer value (^^ rot , ^^ rot , ^^ rot ) of the corresponding color channel (R, G, B) of the 3-channel color camera in the second color space (X, Y, Z) for the first light source.

22. The method (100) according to claim 21, wherein generating the camera value (^^ rot , ^^ rot , ^^ rot) for each of the three color channels (R, G, B) comprises: averaging pixels of the image area of ​​the test camera (K) which lie within the measuring point (813) of the spectrometer (S). Lisa Dräxlmaier GmbH 07.02.2025 1722023-WO-PCT 6 23. The method (100) according to claim 22, comprising: after switching on the first light source, successively switching on the second light source to generate light of the second color (G) and the third light source to generate light of the third color (B); and correspondingly capturing 3-channel color images ^^ grün , ^^ grün , ^^ grün , ^^ blau , ^^ blau , ^^ blau and spectroradiometer measurements ^^ grün , ^^ grün , ^^ grün, ^^ blau , ^^ ^^^^^^^^ , ^^ ^^^^^^^^ for the second light source and the third light source.

24. The method (100) of claim 23, comprising: determining a spectrometer matrix ^^ RGB-LED1 and a camera matrix ^^ RGB-LED1for the first light source based on the acquired 3-channel color images and the acquired spectroradiometer measurements using the following relationships:

25. The method (100) of claim 24, comprising: determining the mapping of the first color space to the second color space for the first light source via a transformation matrix ^^ RGB-LED1 for the first light source via the matrix relationship

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