Method for measuring optical technology or radiometric characteristic quantities and goniometric radiometer

Abstract

The present invention relates to a method and a goniometric radiometer for performing a direction-dependent measurement of at least one optical-technical or radiometric characteristic quantity of a light radiation source (2) installed in an object (1). The method comprises: arranging the object (1) on a turntable (3) which defines a first coordinate system, the object (1) being arranged on the turntable (3) such that the radiation center (2) of the light radiation source is spaced apart from the origin (O) of the first coordinate system; determining the position (relative position) of the radiation center of the light radiation source (2) relative to the origin (O) of the first coordinate system; performing a goniometric radiation measurement which includes rotation of the object (1) in the first coordinate system, wherein the object (1) rotates on the turntable (3) about the rotation axis (31) of the turntable (3); detecting the measurement quantity of the radiation source (2) in a direction-dependent manner by the goniometric radiation measurement; calculating the measurement quantity of a plurality of emission directions in a second coordinate system based on the values of the measurement quantity determined in the first coordinate system and detected in a direction-dependent manner and the relative position, in the second coordinate system, the radiation center of the optical radiation source being at the origin of the coordinate system, wherein the measurement quantity is equal to the characteristic quantity to be measured or the characteristic quantity to be measured is calculated from the measurement quantity.

Description

Technical Field

[0001] The present invention relates to a method and a goniometric radiometer for performing direction-related measurements of at least one optical-technical or radiometric characteristic quantity of a light radiation source mounted in an object. Background Art

[0002] Goniometric radiometers are generally used to measure the optical-technical or radiometric characteristic quantities of lamps and light emitters. These are mechanical-optical measurement systems by which the direction dependence of the quantities used to describe light radiation can be determined. For example, depending on the sensor or the measuring device head used, the luminous intensity distribution or the color distribution body of a light source can be determined. The light source or radiation source is arranged such that its optical center lies at the center of the goniometric radiometer and at the origin of the coordinate system of the spherical coordinate system. In this case, by rotating the light source or radiation source or by successively moving the sensor to different angles, goniometric measurements of the measured values of the optical-technical or radiometric characteristic quantities can be performed, that is, measurements in all directions.

[0003] The optical-technical or radiometric characteristic quantity of the source is obtained by evaluating each direction and / or by integrating the measurement results over a sub-region or the entire solid angle of the distribution body.

[0004] Optical-technical or radiometric characteristic quantities (such as luminous intensity) are direction-dependent quantities, the emission direction of which can generally be specified by two angles in the spherical coordinate system associated with the light source. It has become common to describe with a specific system of planes called the A-plane, B-plane, and C-plane. These planes are described in the document CIE No 70 (1987): "Measurement of the absolute luminous intensity distribution" (Central Bureau of the CIE, ISBN 3 900 734 054).

[0005] In practice, certain types of goniometric radiometers have proven effective, which are also defined in the CIE No.70 (1987) document. For goniometric radiometers of types 1.1 to 1.3, the light source rotates during the measurement, while the sensor is stationary. In type 3 goniometric radiometers, the radiation source rotates about an axis, and the sensor moves along a straight line parallel to the axis of rotation. In this case, the optical center or radiation center of the light source or radiation source lies at the center of the goniometric radiometer.

[0006] There has been an increasing interest in detecting the optical-technical or radiometric characteristic quantities of lamps and light emitters in the state in which they are used (i.e., the installed state). An important application here is the measurement of the lighting quality and / or the optical-technical signal function of vehicle headlamps in the installed state. This type of test is different from the conventional tests of vehicle optical-technical components (headlamps, light emitters) because it also detects the effects and tolerances caused by the installation of these components on the vehicle. These effects are mainly caused by

[0007] - Deviations from the specified installation position, such as tolerances due to vehicle body manufacturing;

[0008] - Deviation of the vehicle from the horizontal plane, for example caused by chassis tolerances, in particular the immersion distance of the springs, which is caused by the influence of the load (number of occupants, driving fuel, i.e., full or empty fuel tank) or the air pressure in the tires;

[0009] - Quality of the headlamp installation at the end of vehicle manufacturing. SUMMARY OF THE INVENTION

[0010] The object of the present invention is to provide a method and a goniometric radiometer for performing direction-related measurements of at least one optical-technical or radiometric characteristic quantity of a light radiation source, which allows the detection of the characteristic quantity of the radiation source in the installed state of the radiation source.

[0011] According to the present invention, this object is achieved by a method having the features of claim 1, a method having the features of claim 20, and a goniometric radiometer having the features of claim 21. Further improvements of the present invention are described in the dependent claims.

[0012] Thus, a first aspect of the present invention provides a method for performing direction-related measurements of at least one optical-technical or radiometric characteristic quantity of a light radiation source installed in an object, the method comprising the following steps (not necessarily implemented in the given order).

[0013] The object is arranged on a turntable having a rotation axis, wherein the rotation axis of the turntable defines a first coordinate system. Exemplarily, the origin thereof is formed by the intersection of the surface of the turntable and the rotation axis and its spatial axes coincide with the rotation axis. The object is arranged on the turntable in such a way that the radiation center of the light radiation source is spaced apart from the origin of the first coordinate system. Exemplarily, if the object is a vehicle, the entire vehicle is arranged on the turntable, and the radiation center of the headlamp is not on the axis of the turntable.

[0014] A goniometric radiation measurement is performed, which includes the rotation of the object about the axis, wherein the goniometric radiation measurement is performed in the first coordinate system, and the object on the turntable rotates about the rotation axis of the turntable starting from the starting position, and the rotation axis of the turntable constitutes the axis of the goniometric radiation measurement. In this case, it can be arranged in such a way that the rotation axis of the turntable extends in the vertical direction, but this is not mandatory.

[0015] In goniometric radiation measurement, for a plurality of emission directions or measurement angles, a direction-related detection of a measured quantity of a radiation source is performed, wherein the emission directions defined in a first coordinate system respectively match the measured values of the measured quantity. For example, each emission direction defined in the first coordinate system matches the value of the measured quantity detected by a sensor. The goniometric radiation measurement is performed in the first coordinate system.

[0016] Furthermore, the position of the radiation center of the light radiation source (exemplarily, in an initial position) is determined relative to the origin of the first coordinate system. This can be done before the goniometric radiation measurement begins. Now it is stipulated that for a plurality of emission directions, the measured quantity is calculated in a second coordinate system, in which the radiation center of the light radiation source is located at the origin of the coordinate system. This is based on the values and relative positions of the measured quantity measured direction-related in the first coordinate system (i.e., the position of the radiation center of the light radiation source relative to the origin of the first coordinate system). The spatial distribution of the measured quantity is thus converted from the distribution measured in the first coordinate system to the spatial distribution in the case where the radiation center of the light radiation source is in the central position.

[0017] The measured quantity can be a characteristic quantity to be measured, or the characteristic quantity to be measured is calculated from the measured quantity. For example, if the measured quantity is the illuminance measured by a sensor, the luminous intensity of the radiation source can be derived therefrom as the characteristic quantity to be measured. According to an embodiment of claim 9, this is done by correcting the distance and the angle of incidence relative to the sensor.

[0018] The method implemented can provide information about the spatial distribution of the characteristic quantity of the radiation source, even though the radiation source is not located at the origin of the coordinate system in which the goniometric radiation measurement is performed.

[0019] Therefore, the present invention is based on the idea that instead of positioning the characteristic quantity to be detected or the function to be tested at the axis center of the goniometer, the goniometric radiation measurement is first performed by an eccentric positioning of the radiation source. By knowing the eccentric position of the radiation source on the turntable, the corresponding measurement angles in the system of the test object or in the system of the radiation source can be calculated. This conversion is based on the coordinate transformation between the respective coordinate systems.

[0020] In other words, the present invention stipulates that the light distribution or the distribution of the characteristic quantity of the radiation source is determined by two coupled coordinate systems. The movement takes place in the first coordinate system, while the light distribution or the distribution of the characteristic quantity to be measured is calculated in the second coordinate system.

[0021] The selection of the two coupled coordinate systems is such that the relationship between the angle (D / S) of the first coordinate system and the angle (H / V) of the second coordinate system is bijective, i.e., there is a one-to-one (eineindeutig) mathematical calculation function for converting from one coordinate system to the other, and a one-to-one (eindeutig) inverse function for converting back from the second coordinate system to the first coordinate system.

[0022] The advantage of the present invention is that even if the radiation source is not at the origin of the radiation measurement, the characteristic quantity to be measured of the radiation source in the installed state can be detected direction-dependently and can be evaluated quantitatively. This enables the measurement to also take into account the effects and tolerances caused by installing the radiation source in an object (e.g., a vehicle).

[0023] As already mentioned, one embodiment of the present invention provides that the object involved is an automobile or a vehicle. It is placed entirely on the turntable. In this case, various built-in radiation sources, such as signal lights like the left headlight, right headlight, turn signal, etc., can be measured in sequence. Of course, the headlight can be measured in various operating modes such as low beam, high beam, and parking light. However, by way of example, the present invention can also be implemented on a spatially extended assembly that is arranged on the turntable and includes eccentrically mounted radiation sources.

[0024] According to one embodiment of the present invention, the axis of rotation of the turntable extends in the vertical direction. This thus enables the weight of the object to be evenly distributed on the turntable. However, in principle, it is also conceivable that the turntable is oriented in space with a certain inclination such that its axis of rotation forms an angle with the vertical direction.

[0025] Of course, it is not possible to detect the characteristic quantity for every emission direction because there are infinitely many emission directions. Instead, a specific grid of emission directions is detected, where each grid represents a specific spatial angle, i.e., a specific part of the total spatial angle. To define the emission directions according to such a grid, it is only necessary to rotate the turntable stepwise, where the rotational positions taken by the turntable each correspond to an emission direction. Alternatively, the turntable rotates continuously, where the measured values are detected at specific time points or at defined angles, and then each measured value corresponds to a specific emission direction.

[0026] One embodiment of the present invention provides that in addition to the rotation of the object on the turntable, the goniometric radiation measurement also includes detecting the characteristic quantity along a straight line according to the position along the straight line. In this embodiment, the goniometric radiometer is a type 3 goniometric radiometer, where the radiation source (which is on the turntable and eccentric there) rotates about an axis and the sensor moves along a straight line.

[0027] In one embodiment, a sensor is used for goniometric radiation measurement, which sensor moves along a straight line and detects measured values of the emitted radiation for predetermined positions on this straight line. The sensor preferably moves on a vertical line extending parallel to the axis of rotation of the turntable, such that the measured quantity is detected along the vertical line, which in combination with the rotation results in an orthogonal grid. In principle, however, the sensor can move along any straight line in space. As an alternative to a single sensor, a plurality of sensors arranged along a straight line can also be provided, such that movement of the sensor is not required.

[0028] The advantage of selecting a type 3 goniometer is that the object or vehicle does not have to be tilted about the horizontal axis. Due to this tilting, forces are generated in the vehicle suspension due to gravity, which in turn affect the orientation of the vehicle relative to the imaginary horizontal plane in relation to the construction. In order to be able to measure the optical-technical functions when mounted on a vehicle in a conventional manner, i.e., without using two coupled coordinate systems, the light source to be measured (low beam, turn signal, etc.) must be moved to the center of the axis of rotation, and after it has been fixedly mounted on the vehicle, the entire vehicle must be moved laterally and then fixed again. In addition to the mechanical challenges, this also results in a greater space requirement, so the dimensions of the laboratory must be many times larger.

[0029] Therefore, according to this aspect of the invention, without affecting the accuracy, the invention proposes to position the vehicle arbitrarily on the rotating device and then precisely measure the position of the optical function to be measured relative to the axis of rotation.

[0030] The height of the turntable on which the object or vehicle is located represents the street height, and all optical-technical measured quantities are referenced to this height in further evaluation to determine the lighting situation caused by the vehicle on the street.

[0031] One embodiment provides that, as the measured quantity, the illuminance is measured and the luminous intensity of the radiation source as the characteristic quantity to be measured is calculated from this illuminance using the following formula:

[0032]

[0033] Where:

[0034] I is the luminous intensity,

[0035] E is the measured illuminance,

[0036] d is the distance between the light source and the sensor, and

[0037] (H, V) is the angle at which the sensor fixedly oriented parallel to the X-axis is illuminated, i.e.,

[0038] H corresponds to the azimuth angle φ, and

[0039] V corresponds to 90° minus the polar angle θ in the usual representation of spherical coordinates.

[0040] For example, in order to calculate the luminous intensity from the measured illuminance, the distance d between the light source and the sensor as well as the angles H and V must be known. The formula assumes that the sensor is oriented parallel to the X-axis (H = 0). This distance correction takes into account that the sensor surface of the sensor or photometer is exposed to a reduced luminous intensity when the light falls at an angle, as well as the distance between the radiation source and the sensor.

[0041] One variant embodiment provides that, in addition to the rotation of the object on the turntable and the detection of characteristic quantities along a straight line depending on the position along this line, the goniometric radiometry includes the detection of characteristic quantities along a second straight line depending on the position along this second straight line, wherein the first straight line and the second straight line are parallel and arranged at different distances from the origin of the first coordinate system. The two lines or linear axes are preferably arranged at different distances, for example at 25 m and 5 m without limiting generality. With such an arrangement, the headlamp and signal functions can be optimally measured during the setup of the vehicle.

[0042] It is pointed out here that the radiation center of the radiation source can basically be defined in different ways. For example, it can be the center of the incandescent filament. Another way is to define the radiation center of the radiation source as the geometric focus of the radiation beam passing through the closed glass plate (Abschlussscheibe) that separates the radiation source from the environment. Exemplarily, the closed glass plate is the headlamp glass from which the light beam emerges. The radiation center defined in this way is usually identified by the manufacturer by means of a marking in the closed glass plate.

[0043] Another embodiment of the invention provides that the calculation of the direction-related characteristic quantities in the second coordinate system is carried out based on the direction-related detected values of the measured quantities in the first coordinate system, which is achieved by mapping the coordinates of the measured values detected in the first coordinate system to the corresponding coordinates in the second coordinate system. Basically, any coordinate system can be used, such as the Cartesian coordinate system, the cylindrical coordinate system, and the spherical coordinate system. Exemplarily, in the spherical coordinate system, each emission direction is defined by the azimuth angle and the polar angle.

[0044] The variant embodiment with a turntable and a linear axis provides that the first coordinate system is the cylindrical coordinate system, the coordinates of the values detected in the first coordinate system are converted in a first step to another cylindrical coordinate system with the radiation center of the radiation source at its origin, and in a second step to the spherical coordinate system with the radiation center of the radiation source at its origin, where the spherical coordinate system is the second coordinate system. Thus, the conversion to the spherical coordinate system with the radiation center of the radiation source as the origin takes place through an intermediate calculation of the coordinates in the intermediate coordinate system. However, this is only an exemplary embodiment. In principle, a direct conversion between the first coordinate system and the second coordinate system can also be carried out. Any suitable mathematical method can be used here.

[0045] The above-described variant embodiment provides that for each emission direction, the position of the sensor in the first coordinate system is calculated from the rotation angle D of the turntable and the height S of the sensor, and therefrom the azimuth angle H and elevation angle V of the sensor position in the second coordinate system are calculated, and the values of the measurement parameters measured by the considered sensor are matched to the emission direction defined by the azimuth angle and elevation angle. The corresponding measured values are also corrected with respect to the distance and the angle of incidence relative to the sensor in order to obtain characteristic quantities from the measured quantities, in particular to calculate the luminous intensity from the illuminance.

[0046] According to another embodiment, the goniometric radiometric measurement is not carried out according to type 3 but using a camera. Here it is provided that, in addition to the rotation of the object on the turntable, the goniometric radiometric measurement also includes detecting the measured quantity by means of a stationary camera, where the radiation emitted by the radiation source is reflected on the reflection measurement wall in a diffuse, non-directional manner, and the brightness distribution on the measurement wall is detected by the camera for at least two positions of the turntable. The brightness distribution detected by the camera is converted into a brightness distribution in the second coordinate system by means of a coordinate transformation. The brightness distribution represents the measured quantity.

[0047] This measuring device is basically based on a goniometric radiometric measuring device as described in WO 2016 / 116300 A1.

[0048] According to this variant embodiment, only the rotational movement of the vehicle and the camera-measurement wall measurement system are required for the goniometric radiometric measurement in order to be able to detect the entire angular range in a single brightness image. Then a coordinate transformation is used to convert the brightness distribution measured by the camera on the wall into the luminous intensity distribution of the headlight.

[0049] Here, with the object arranged on the turntable, the brightness distribution presented on the measurement wall already defines a large solid angle, that is to say, two-dimensional measured values for the individual emission directions are detected through the objective lens of the camera within the solid angle delimited by the measurement wall. If the measurement wall is high enough such that the vertical distribution of the far-field radiation source can be completely depicted, then, based on the presentation or brightness distribution on the measurement wall, the dependence of the characteristic quantity to be measured on the polar angle can be determined. By rotating the turntable, other solid angles for other azimuth angles are presented on the measurement wall. Depending on the width of the measurement wall, the brightness distribution at at least two positions of the turntable is detected (otherwise it is not a goniometric radiometric measurement), where the entire light distribution consists of the arrangement of the individual solid angle meshes.

[0050] The coupled coordinate system is also used in a variant embodiment with a camera, i.e., the transformation from wall coordinates (where the luminance camera determines the measured values) to spherical coordinates in the headlamp reference system changes as the headlamp rotates in space. If the coordinates of the headlamp are known to depend on the angle of the rotation device, a bijective mapping can again be found, using which the light distribution in the reference system of the detected object can be calculated from the angle of the rotation device and the height of the headlamp.

[0051] Then several sub - angle ranges can be combined into a total angle distribution. The advantage of this method is that, compared to sequential grid measurements based on sensors or photometers, data can be obtained faster by combining vehicle rotation and camera measurements, and there is no requirement for the position of the headlamp on the turntable - it only needs to be accurately determined.

[0052] One embodiment stipulates that the measurement wall is arranged in the far - field of the light distribution of the radiation source, that is, at a distance where the radiation source can be approximated as a point source. For example, the measurement wall is 25 m away from the radiation source in its starting position.

[0053] Another embodiment stipulates that the light of the radiation source also directly irradiates another sensor and the signal detected by this sensor is used to calibrate the camera. Since the measurement uncertainty of camera measurements is much greater than that of sensor measurements (usually using a photometer), the data obtained by the camera can be selectively corrected using the sensor. The other sensor can be a sensor arranged in front of or on the side of the measurement wall. The sensor can also be arranged behind the measurement wall and be irradiated through an opening in the measurement wall.

[0054] The advantages of using another sensor for correction, in addition to reducing measurement uncertainty, are that the traceability of the measured values is achieved through the sensor or photometer, and the measurement wall - camera combination does not have to be absolutely calibrated.

[0055] Another embodiment of the present invention stipulates that, in addition to the rotation of the object on the turntable, the goniometric radiometric measurement also stipulates that the turntable or the object is tilted about an axis perpendicular to the rotation axis, where the object rotates on the turntable at a plurality of tilt angles, and the measured quantity is detected for each combination of the rotation angle and the tilt angle, and the measured quantity is detected based on goniometric radiometric measurement on the spherical surface around the radiation center of the radiation source. In particular, the object is also tilted about the horizontal axis (by tilting the turntable or the object). It can be stipulated that a position - fixed sensor is used for goniometric radiometric measurement, and this sensor records the measured values of the emitted radiation for each combination of the rotation angle and the tilt angle.

[0056] In this case, a suitable measurement system is used to detect the angle of tilt of the turntable or the object, where (if the object on which the radiation source is mounted is a vehicle) the tilt angle of the turntable or the tilt angle of the vehicle body is detected.

[0057] The advantage of this arrangement is that there is no need to move the sensor along the linear axis to measure the elevation angle in the coupled coordinate system for goniometric radiation measurement. Instead, it can be accomplished by tilting the vehicle forward or backward. Thus, the photometer can be designed to be fixed, which is advantageous, for example, when the room height is limited. However, for this variant embodiment, it is necessary to detect and correct the initially mentioned drawback of the vehicle tilting towards the chassis. Exemplarily, this can be done by cameras attached to the left and right sides of the vehicle, which measure the marked points on the vehicle body and thus detect the actual tilt angle of the vehicle relative to the horizontal zero position, so that chassis effects such as spring deflection or tire pressure do not distort the vertical angle.

[0058] In this exemplary embodiment, the measurement is carried out by the rotation of the platform on which the tilted vehicle is placed and in combination with the tilt, such that the headlight moves around the center point of the rotating device on an arc tilted by the tilt angle. However, the current measurement geometry is described by a coupled spherical coordinate system with the origin on the sphere.

[0059] One variant embodiment stipulates that the direction-related measurement quantity in the second coordinate system is calculated based on the direction-related detected value of the measurement quantity in the first coordinate system, which is carried out by mapping the coordinates of the value detected in the first coordinate system to the corresponding coordinates in the second coordinate system, where the second coordinate system is a spherical coordinate system with the origin moving on the sphere.

[0060] According to a second aspect of the present invention, the present invention relates to a method for direction-related measurement of at least one optical-technical or radiometric characteristic quantity of a light radiation source installed in an object, which comprises the following steps:

[0061] - Arranging the object at or on a holding element, which is provided and designed to rotate the object around a first axis and a second axis perpendicular to the first axis, wherein the object is arranged on the holding element such that the radiation center of the light radiation source is located outside the origin of the first coordinate system formed by the first axis and the second axis,

[0062] - Determining the position (relative position) of the radiation center of the light radiation source relative to the origin of the first coordinate system,

[0063] - Performing goniometric radiation measurement, which includes the rotation of the object around two axes, wherein the goniometric radiation measurement is carried out in the first coordinate system,

[0064] - Direction-related detection of the measurement quantity of the radiation source by means of goniometric radiation measurement of a plurality of emission directions, wherein the emission directions defined in the first coordinate system respectively match the measured values of the measurement quantity,

[0065] - Based on the values of the direction-related measurement quantities determined in the first coordinate system and the relative position detected in relation to the direction, calculate the measurement quantities for a plurality of emission directions in the second coordinate system, where the radiation center of the light radiation source is located at the origin of the coordinate system in the second coordinate system.

[0066] - Wherein the measurement quantity is equal to the characteristic quantity to be measured, or the characteristic quantity to be measured is calculated based on the measurement quantity.

[0067] The difference between this method and the method according to claim 1 is that the object is not arranged on a turntable but rotates around two axes, corresponding to classical goniometric radiation measurement using a goniometric radiometer of type 1. Although here the radiation center of the radiation source is located outside the origin of the coordinate system where the measurement is performed, and then a conversion to the second coordinate system is carried out. The object is arranged anywhere in space and is held by a robotic arm serving as a holding element, and the holding element can rotate the object around multiple axes.

[0068] Another aspect of the present invention relates to a goniometric radiometer for performing direction-related measurements of at least one optical-technical or radiometric characteristic quantity of a light radiation source installed in an object, wherein the goniometric radiometer comprises:

[0069] - A turntable having a rotation axis, wherein the rotation axis of the turntable defines a first coordinate system, the origin of which is formed by the intersection of the surface of the turntable and the rotation axis, and whose spatial axis coincides with the rotation axis, and wherein the turntable is arranged to carry the object such that the radiation center of the light radiation source is spaced apart from the origin of the first coordinate system.

[0070] - At least one sensor designed to measure the measurement quantity.

[0071] - Wherein the turntable and the at least one sensor are designed to perform goniometric radiation measurement in the first coordinate system, which includes the rotation of the object around the rotation axis of the turntable, wherein, by means of goniometric radiation measurement for a plurality of emission directions, the measurement quantity is detected in relation to the direction, and wherein the emission directions defined in the first coordinate system respectively match the measured values of the measurement quantity.

[0072] - A calculation unit for calculating the measurement quantity for a plurality of emission directions in the second coordinate system, where the radiation center of the optical radiation source is located at the origin of the coordinate system, and this calculation is carried out based on the position of the radiation center of the optical radiation source relative to the origin of the first coordinate system and based on the direction-related detection values of the measurement quantity determined in the first reference system.

[0073] - Wherein the calculation unit is further designed to calculate the characteristic quantity to be measured based on the measurement quantity, provided that the measurement quantity is not yet the characteristic quantity to be measured.

[0074] Using such a goniometric radiometer, the method according to claim 1 can be implemented. In particular, the goniometric radiometer can be a type 3 goniometric radiometer, in which at least one sensor detects a measured quantity along a straight line according to the height position along the straight line.

[0075] In particular, with the goniometric radiometer according to the invention, the lighting quality or the optical signal function of the vehicle headlamps can be evaluated in the installed state. This test is different from the conventional tests of the vehicle's optical components (headlamps, vehicle lights) because the effects and tolerances caused by the installation of these components on the vehicle are also detected.

[0076] In an embodiment of the invention, the goniometric radiometer is arranged and designed to implement the method variants given in claims 2 - 18.

[0077] One variant embodiment provides that the goniometric radiometer further has:

[0078] - a measurement wall with diffusive reflectivity, which reflects the light emitted by the radiation source,

[0079] - a camera arranged in a position - fixed and immovable manner, which has a two - dimensional sensor chip, wherein the pixels of the sensor chip form at least one sensor,

[0080] - wherein the camera is arranged and designed such that it detects the light reflected on the measurement wall for at least two positions of the turntable, wherein the reflected light is imaged on the sensor chip of the camera, and wherein the reflected light is detected by the camera as the brightness distribution on the measurement wall,

[0081] - wherein the computing unit is designed to convert the brightness distribution detected by the camera into a brightness distribution in a second coordinate system using coordinate transformation.

[0082] Another embodiment provides that

[0083] - at least one sensor includes a fixed sensor,

[0084] - the turntable is designed such that in addition to rotating about the rotation axis, the object arranged thereon is tilted about an axis perpendicular to the rotation axis, or the object is arranged to be tiltable about this axis,

[0085] - wherein the turntable or the object and at least one sensor cooperate in the goniometric measurement such that the object rotates on the turntable at a plurality of tilt angles in the goniometric measurement, and the position - fixed sensor detects the characteristic quantity to be measured for each combination of the rotation angle and the tilt angle.

[0086] It should be noted that for the purpose of this disclosure, the terms mentioned below are defined as follows.

[0087] The terms optical technology (lichttechnisch) and photometry (photometrisch) may also include the term radiometry (radiometrisch), provided that characteristic quantities of infrared (IR) or ultraviolet (UV) light are measured.

[0088] The term sensor includes all embodiments for measuring optical radiation (ultraviolet, visible, and infrared light) in the wavelength range from 100 nm (UV-C) to 1 mm (IR-C). According to an exemplary embodiment, the sensor is designed as a photometer.

[0089] When detecting the light distribution of an optical technology device using any sensor (photometer or radiometer), the terms goniophotometer and goniometer can be used interchangeably. When talking about a goniometer, all embodiments are always involved, regardless of which sensor is used.

[0090] The term vehicle can include all types of vehicles, particularly vehicles for road, rail, water, or air transportation. The following exemplary embodiments generally relate to passenger cars (PKWs).

[0091] In addition to headlights for illuminating the road or signaling devices in a vehicle, the term optical technology device can also include optical technology devices for traffic routes. Description of the Drawings

[0092] The present invention will be explained in more detail below with reference to several exemplary embodiments using the accompanying drawings.

[0093] Figure 1 The basic structure of a goniometer is shown, where, for goniometric radiation measurement, the object arranged on the turntable rotates, the radiation source is eccentrically mounted in the object, and the sensor moves vertically along the rod;

[0094] Figure 2 A cylindrical coordinate system is schematically shown, whose origin moves on a circular arc.

[0095] Figure 3 Schematically shown according to Figure 1 the measurement geometry of the goniometer.

[0096] Figure 4 Schematically shown Figure 3 an enlarged view of the turntable and the object in the measurement geometry;

[0097] Figure 5 Schematically shown is the coordinate mapping from a cylindrical coordinate system whose origin moves on a circular arc to a spherical coordinate system whose origin moves on a circular arc.

[0098] Figure 6 Shows Figure 1A variant of the goniometric radiometer, in which two vertical rods with sensors that can move thereon are provided at different distances from the turntable;

[0099] Figure 7 Another exemplary embodiment of the goniometric radiometer is shown. In addition to the rotating turntable, the goniometric radiometer further includes a reflection measurement wall and a camera;

[0100] Figure 8 A spherical coordinate system is schematically shown, the origin of which moves on an arc and is mapped on the projection wall.

[0101] Figure 9 A spherical coordinate system is schematically shown, the origin of which moves on the spherical surface.

[0102] Figure 10 A schematic diagram of the spherical coordinate system is shown. Detailed implementation

[0103] For the general background of the present invention, first refer to Figure 10 . Figure 10 Represents a spherical coordinate system, which shows the definitions of the angles Phi φ and Theta θ. If the radiation source is at the origin of this spherical coordinate system, the optical technical characteristic quantities and radiometric characteristic quantities of the radiation source can be measured goniometrically for all directions successively within the angular ranges of -180° ≤ φ ≤ 180° and 0 ≤ θ ≤ 180° by rotating the radiation source or moving the sensor. Thus, the emission direction can be defined by two angles φ and θ.

[0104] Generally, through goniometric radiometry, for a plurality of emission directions i or angle pairs φ i , θ i Specific luminous intensities of the radiation source, or other optical technical characteristic quantities or radiometric characteristic quantities, are respectively matched. This characteristic quantity is measured on the spherical surface or a sub-region of the spherical surface by means of a sensor, or is derived from the measurement values detected by the sensor. In this way, the spatial distribution of the luminous intensity or the measured characteristic quantity is determined, which defines the radiation source. For a vehicle headlamp, for example, it is extremely important to accurately determine the spatial distribution of the characteristic quantity involved or to accurately comply with the preset spatial values of the characteristic quantity involved.

[0105] When measuring a vehicle headlamp, the headlamp (left or right) can first be measured separately as a single object using a conventional goniometric radiometer, and then the light distributions of the individual headlamps are superimposed to simulate the light distribution on the road. This component measurement using a goniometer ignores many factors, especially the installation state of the headlamp on the vehicle.

[0106] Figure 1Shows a first exemplary embodiment of a goniometric radiometer according to the present invention. The goniometric radiometer includes a turntable 3 that can rotate about a rotation axis 31. The turntable 3 is located on a base 35. However, this should only be understood as an example. Alternatively, other measures can be provided such that the angular range radiating downward from the plane of the turntable 3 can be detected optically, for example, by arranging the turntable 3 in a higher mezzanine.

[0107] At least in the area where the vehicle is located, the turntable 3 has a flat surface 32, which together with the rotation axis 31 defines a first coordinate system. The origin of the first coordinate system is formed by the intersection of the surface 32 of the turntable 3 and the rotation axis 31, and its spatial axis (z-axis) coincides with the rotation axis 31. Here, the rotation axis 31 extends vertically.

[0108] The vehicle 1 is arranged on the turntable. It usually has two headlights 2, and goniometric radiometric measurements are performed on each headlight in terms of optical or radiometric characteristic quantities. In this case, the vehicle 1 is basically arranged at the center of the turntable 3, such that the headlights 2 are spaced apart from the origin of the first coordinate system formed as described and the rotation axis 31.

[0109] To perform goniometric radiometric measurements, a vertically extending rod 40 is also provided, on which the sensor 4 can move vertically at different height positions S. The rod 40 extends from a bottom surface that is lower relative to the plane of the turntable 3, so that the radiation emitted downward by the headlights 2 can also be detected.

[0110] A measurement wall 5 is also shown, which diffusely reflects the emitted headlight rays. In the exemplary embodiment involved, the measurement wall 5 has nothing to do with the goniometric radiometric measurements to be performed, but can be used for the visualization of the headlight orientation and the visual inspection of the lighting distribution generated by the headlights. The shortest distance between the rotation axis 31 and the measurement wall 5 is denoted by r.

[0111] The rod 40 with the sensor 4 and the measurement wall 5 are both located in the far field of the headlights of the vehicle 1, where, for example, a distance of 25 m is selected as the distance.

[0112] The goniometric radiometer provided by the shown configuration is a type 3 goniometric radiometer, in which the rotation about the rotation axis (here referring to the rotation axis 31 of the turntable 3) is combined with the movement of the sensor (here referring to the sensor 4) along a vertical straight line. The measurement is performed in such a way that for a specific rotational angle position of the turntable 3, the sensor 4 moves vertically, and a plurality of measurement values corresponding to the respective height positions S are recorded. The above operation is repeated for a plurality of rotational angle positions of the turntable 3. Alternatively, when a height position S of the sensor 4 is given, the turntable 3 is moved to different turntable setting positions, and the above operation is repeated for different height positions S.

[0113] During a measurement process, only one radiation source is activated at a time, which is the left headlight in the exemplary embodiment shown.

[0114] In principle, the sensor 4 can be any sensor suitable for measuring optical radiation in the wavelength range from 100 nm to 1 μm or a sub-range of this wavelength range. For example, it is a photometer. It can be stipulated that the sensor 1 performs partial filtering or full filtering such that the sensitivity of the sensor coincides with the sensitivity curve of a normal eye. For example, the sensor 4 provides a luminance value as the output value.

[0115] For example, the sensor 4 moves along the rod 40 to height positions S, the vertical distances between which correspond to angles of 0.05°, 0.1°, 0.15° or 0.2°. However, this should only be understood as an example.

[0116] However, in the goniometric radiation measurement carried out in this way, the procedure is as follows: the direction-related detection of the characteristic quantity to be measured of the radiation source (headlight) is carried out in a plurality of emission directions of the first coordinate system. Therefore, the spatial distribution of the illuminance or other characteristic quantity determined by the measurement does not provide information about the spatial distribution of the said characteristic quantity of the radiation source.

[0117] In order to determine the spatial distribution of the said characteristic quantity of the radiation source, on the one hand, taking into account the position of the radiation center of the light radiation source relative to the origin of the first coordinate system, and on the other hand, taking into account the values of the characteristic quantity detected directionally in the first coordinate system, the characteristic quantity involved is transformed into a second coordinate system in which the radiation center of the light radiation source is located at the origin of the coordinate system.

[0118] It should be noted that in the following description of the drawings, for simplicity, the terms "measurement quantity" and "characteristic quantity" are used as synonyms. The measurement quantity is the measured value measured by the sensor. The characteristic quantity can be the same as the measurement quantity or can be derived from the measurement quantity. For example, if the measurement quantity is illuminance, the luminous intensity as the characteristic quantity of the radiation source can be calculated from the illuminance by distance correction, where the distance correction takes into account the fact that the light intensity received by the surface of the sensor or photometer decreases when the light is obliquely incident, and also further takes into account the distance between the radiation source and the sensor.

[0119] Exemplarily, the exact position of the radiation center of the light radiation source relative to the origin of the first coordinate system can be determined using a tactile measurement system that probes specific markings on the vehicle and thereby calculates the relative position. Exemplarily, such a tactile measurement system is manufactured and sold by Flexagon Metrology under the name "ROMER ABSOLUTE ARM". It should also be noted here that the radiation center of the headlight installed in the vehicle is usually indicated by the manufacturer by a marking that is integrated into the closed glass plate of the headlight and indicates the geometric center of the radiation beam emerging from the closed glass plate. Exemplarily, in this way, the exact position of the radiation center relative to the origin of the first coordinate system can be accurately detected.

[0120] The characteristic quantities of multiple radiation directions are converted into corresponding values in the second coordinate system by mapping or coordinate transformation. For this purpose, reference Figures 2 - 5 , a variant embodiment is described below, in which such a coordinate transformation occurs, that is, the detected values are detected in the first coordinate system that is a cylindrical coordinate system. The first step is to transform the detected values to another cylindrical coordinate system, where the radiation center of the radiation source is located at the origin of this cylindrical coordinate system, and the second step is to transform the detected values to a spherical coordinate system (while taking into account the distance problem), where the radiation center of the radiation source is located at the origin of this spherical coordinate system, and the spherical coordinate system is the desired second coordinate system.

[0121] Figure 2 and Figure 5 illustrate this process. Figure 2 shows a cylindrical coordinate system whose origin moves on an arc. The trajectory of the cylindrical coordinate system moving with the origin is denoted by T. The trajectory D corresponds to the movement of the headlight of the vehicle 1 on the turntable 3. The turntable 3 or the headlight rotates by an angle D from the starting position A1. In Figure 2 's illustration, the headlight has rotated to the position A2. Figure 2 shows the common parameters of the cylindrical coordinate system. The height S represents the height position of the sensor 4 according to Figure 1 . The planar distance from the headlight to the sensor 4 is denoted by p in the cylindrical coordinate system.

[0122] It should be noted that Figure 2 's cylindrical coordinate system represents the aforementioned intermediate coordinate system. The measured values are first recorded in the first coordinate system that passes through the origin O and rotates around the rotation axis 31, where the first coordinate system is also a cylindrical coordinate system. Now the problem is to transform the measured values in the first step to the intermediate coordinate system with parameters φ, p, and S (where p and S can also be measured) based on the rotation angle D, and then calculate the parameters H and V from the parameters φ, p, and S in the second step, where, according to Figure 5The illustration on the right side, where parameter H is the azimuth angle and parameter V is the elevation angle in the spherical coordinate system (defined as 90° minus the polar angle θ). Thus, the spatial distribution to be determined of the characteristic quantity to be detected is detected with respect to the spherical coordinate system in which the radiation center of the radiation source is located at the coordinate origin.

[0123] Therefore, each rotation angle D is associated with a local cylindrical coordinate system. For this local cylindrical coordinate system, the local azimuth angle φ (corresponding to H in the plane system A, α) is determined, and then the local elevation angle V = 90° - θ in the headlight object system is calculated based on the height S and the local radius p, and then distance correction is performed according to the desired characteristic quantity (e.g., luminous intensity).

[0124] Exemplarily, the goniometric radiation calculation is performed by Figure 1 the calculation unit 6 schematically shown in, for calculating the characteristic quantity of a plurality of emission directions in the second coordinate system. The calculation unit 6 detects the rotation angle of the turntable 3, the height S of the sensor 4, and determines the preset distance in the measurement system. The measured values measured by the sensor 4 are also fed to the calculation unit 6. At the same time, the calculation unit can provide control instructions, such as rotating the turntable 3 by a specific angle D or moving the sensor 4 to a specific height S.

[0125] The following takes Figure 3 and Figure 4 as examples to illustrate this calculation in detail, where Figure 4 is Figure 3 an enlarged view of the left sub-region.

[0126] Measuring geometry

[0127] Figure 3 and Figure 4 The measurement geometries in are as follows. The origin O = (0, 0) of the coordinate system is the intersection of the axis 31 of the turntable 3 and the surface 32 of the turntable 3. The angle between the turntable 3 and the X-axis is equal to D. The X-axis points to the right side of the screen, and in the positive rotation direction (canonically, i.e., the light comes from the left), the positive direction of the Y-axis points upward in the drawing plane, and the Z-axis points upward from the paper plane.

[0128] The headlamps 2 are located at the starting position A1 on the reference line F, at a fixed distance a from the rotation center. However, their positions in space must be determined during the measurement operation in order to thereby find the zero position of the vehicle 1. The lateral distance from the headlamps to the center plane of the vehicle 1 is b, where the center plane of the vehicle 1 extends along the X-axis within the manufacturing tolerances and positioning accuracies.

[0129] Calculations are performed using a two-dimensional rotation matrix and analytic geometry in the plane. For basic considerations, a point P(x, y) in 2 needs to be rotated by D:

[0130]

[0131] All important points are rotated out of the zero position in the (x, y) plane, and the corresponding vectors are then calculated and attached to the headlamp 2 acting as a radiation source.

[0132] Characteristic quantity measurement and calculation are continuously performed on the two headlamps of the vehicle 1. That is to say, when one headlamp 2 is measured, the other headlamp is turned off or covered, and vice versa. In this embodiment, the left headlamp 2 is considered.

[0133] Calculating H and p from D

[0134] First, the azimuth angle φ (or H) and the local radius p in the local cylindrical coordinate system are determined according to the rotation angle D, where the local radius p is the distance between the headlamp 2 and the base point of the position of the sensor 4 in the plane involved.

[0135] The geometry is as follows:

[0136]

[0137]

[0138] The parameters of the activated headlamp are as follows:

[0139] The photometer position parameters are as follows:

[0140] The measurement distances are as follows:

[0141]

[0142] The vanishing point or the optical axis of the activated headlamp is also rotated. In the non-rotating state (D = 0), the headlamp is aligned

[0143] Based on such geometry and parameters, the azimuth angle φ (or H) and the local radius p in the local cylindrical coordinate system can be calculated as follows.

[0144] When rotated by D, is rotated to Mathematically, this is done using the same matrix as :

[0145]

[0146] Vector from the activated headlamp to the new vanishing point

[0147]

[0148] Having an angle h with respect to the optical axis c . h c Is the same as D.

[0149]

[0150] Therefore, the angle of the headlight with respect to the photometer is

[0151]

[0152] Thus, H in the local cylindrical coordinate system ( Figure 2 ) is determined.

[0153] The local radius p is equal to:

[0154]

[0155] Or

[0156]

[0157] The local radius p does not necessarily need to be calculated because, by definition, it is consistent with d in the measurement geometry involved and is thus 25 m in the example involved.

[0158] Similarly, D can in turn be determined from H. This is important in practice, for example, when intending to approach a specific angle H.

[0159] The next step is to determine the spherical coordinates H and V in the spherical coordinate system according to Figure 5 the right figure.

[0160] The azimuth angle H is the same as in the local cylindrical coordinate system:

[0161]

[0162] The angle V is obtained from the relationship between S and V using p and D:

[0163] S = p tan V

[0164] And

[0165]

[0166] And

[0167] If D and S are given, V can be determined relatively easily.

[0168] Finally, the radius R in spherical coordinates can also be calculated from V and S, for example:

[0169]

[0170] The spatial distribution of the characteristic quantity to be measured (e.g. luminous intensity) can thus be given in a spherical coordinate system, at the center of which the radiation center of the radiation source is located. In addition, a distance correction can be performed. Further analysis of the equations shows that there is a bijective mapping in the definitions or angle ranges involved.

[0171] Figure 6 Shown based on Figure 1 Another exemplary embodiment of the exemplary embodiment in . In this case, a second rod 41 with a second sensor 4 is also provided, and the sensor can also be moved to different height positions in the vertical direction along the rod 41. Here, the second rod 41 is arranged closer to the turntable 3 than the first rod 40, for example, 5m away, while the turntable 3 is 25m away from the first rod 40. Figure 1 Likewise, according to Figure 6 The arrangement includes a computing unit, although it is not shown separately.

[0172] This arrangement allows simultaneous goniometry of multiple radiation sources, for example, the closer sensors 4 are used to optimally measure signal lights on vehicles, such as turn signals. For signal lights, the far field already exists at a distance of 5m, so a larger vertical angle can be measured at the same room height.

[0173] Figure 7 An exemplary embodiment is shown in which, for angular radiometric measurement, a vehicle 1 arranged on a turntable 3 is rotated into at least two rotational positions and the light reflected on a measuring wall 5 is detected by a schematically shown stationary camera 7 .

[0174] In this case, the camera 7 comprises a two-dimensional sensor chip, wherein the pixels of the sensor chip can be understood as sensors within the meaning of the present invention. Here, each pixel of the two-dimensional sensor chip matches a wall unit of the measuring wall 5. Exemplarily, the sensor chip is a two-dimensional CCD sensor or a CMOS sensor. The camera 7 has an optical device that guides the incident light onto the sensor chip.

[0175] The measuring wall 5 is designed in such a way that it reflects the incident radiation uniformly in all directions by diffuse reflection, without directional reflection. In particular, it is grey or white in order to minimize the spectral influence of the reflection. Therefore, the measuring wall 5 is not a mirror with directional reflection that satisfies the law of reflection.

[0176] The camera 7 is arranged and designed to detect the light reflected on the measurement wall 5, wherein the reflected light is imaged onto the sensor chip of the camera 7. For at least two positions of the turntable 3, the reflected light is detected by the camera 7 as the brightness distribution on the measurement wall 5. The associated calculation unit 6, only schematically shown, is designed to convert the brightness distribution recorded by the camera 7 into a brightness distribution in a second coordinate system by means of a coordinate transformation.

[0177] The calculation unit 6 performs a goniometric radiation calculation. It records the rotation angle D of the turntable 3 and the measurement data from the camera 7. At the same time, the calculation unit can provide control commands, such as rotating the turntable 3 by a specific angle.

[0178] The radiation source 2 generates a light distribution 9 on the measurement wall 5, which corresponds to the typical light distribution of a vehicle headlamp in the shown exemplary embodiment. For each pivoting movement around the axis 31, the light distribution 9 is detected by the sensor chip of the camera 7. The measurement wall 5 is in the far field of the light distribution of the radiation source mounted in the vehicle. For example, it is located 5 m away from the headlamp or the radiation source 2.

[0179] This exemplary embodiment is characterized in that, instead of the linearly moving photometer according to the Figure 1 exemplary embodiment therein, a photometrically corrected camera-measurement wall system is used, and the camera measures the reflected brightness of the luminance or illuminance caused by the vehicle lighting system on the measurement wall. In this case, only the steering movement of the vehicle and the camera-measurement wall measurement system are required to detect the entire angular range in a single brightness image. Then, the brightness distribution measured by the camera on the wall is converted into the luminous intensity distribution of the headlamp by means of a coordinate transformation.

[0180] A coupled coordinate system is also used here, that is, the conversion from wall coordinates to spherical coordinates in the headlamp reference system changes with the rotation of the headlamp in space, where the luminance camera determines the measured values in wall coordinates. If the coordinates of the headlamp are known to depend on the angle of the rotating device, a bijective mapping can be found again, using which the light distribution in the detection object reference system can be calculated based on the angle of the rotating device and the height of the headlamp.

[0181] Then, multiple partial angular ranges can be combined to form an overall angular distribution. The advantage of this method is that, compared with the sequential grid measurement based on a photometer, data can be obtained faster by combining vehicle rotation and camera measurement.

[0182] However, compared with the direct measurement using a photometer, the dynamic range measured in the case of indirect measurement using the camera 7 is smaller. This is because when using the camera 7, the suppression of scattered light is limited both in the measurement space and in the objective lens. Therefore, a great deal of effort is required to achieve a contrast ratio of more than 100:1. Taking this into account, a sensor 8 with a fixed arrangement having a higher dynamic range can be provided to calibrate the prominent points of the light distribution. Such an additional sensor 8 is schematically shown in Figure 7 . For this purpose, according to an alternative embodiment, an opening (not shown) is formed in the measurement wall 5 (e.g., on the optical axis of the radiation source), and the light emitted by the radiation source passes through this opening and is detected by this additional sensor. In this case, the additional sensor on the axis is either located behind the measurement wall 5 or at the opening. Ideally, the sensor surface is part of the measurement wall and has similar reflection or scattering characteristics with respect to the incident light. Alternatively, such a sensor 8 is arranged in front of or beside the measurement wall 5, where the sensor is in the far field. It can also be provided that such a sensor 8 can be moved, so that multiple positions in front of the measurement wall 5 can be adopted.

[0183] Such a sensor 8 can be used to accurately calibrate the entire light distribution area detected by the measurement wall. Since the position of this additional sensor 8 is known, the combination of the measurement wall 5 and the camera 7 only needs to be used to determine the angle of the prominent points of the light distribution. This is associated with the advantage of the traceability of the measured values, because the combination of the measurement wall 5 and the camera 7 does not have to be absolutely calibrated, but can be calibrated with a photometer during the measurement.

[0184] As described above, the camera 7 detects the solid angle defined by the measurement wall 5 for each rotational position of the turntable 3. By stringing together the individual solid angles at different rotational positions of the turntable 3, the entire light distribution within the larger solid angle range involved can be integrated, especially in a coordinate system where the radiation source or the headlamp is located at the origin of coordinates. The corresponding projection is shown by Figure 8 .

[0185] Another alternative exemplary embodiment provides that Figure 1 the turntable 3 can also be tilted about an axis perpendicular to the rotational axis 31, for example, about the Y axis. Thus, the turntable 3 itself realizes the movement of the radiation source around the first axis 31 and the second axis perpendicular to the first axis 31 during the measurement process. In this case, of course, not all spatial directions of the sphere can be detected by goniometric radiation measurement, but only the forward-oriented solid angles can be. However, this is sufficient for applications measuring headlamp illumination.

[0186] Optionally, the vehicle can also be tilted about a transverse axis on the turntable, for example by raising the front or the rear, which achieves the same effect as tilting the turntable.

[0187] In this embodiment, for goniometric radiation measurement, it is sufficient to use a sensor with a fixed position, which records the measured values of the radiation emitted in combinations of various rotation angles and tilt angles, and this measured value is equal to the characteristic quantity to be determined, or the characteristic quantity to be determined is derived from this measured value. Using a sensor with a fixed position is advantageous, especially when the room height is limited.

[0188] It can be provided that the vehicle body tilt, which corresponds to the turntable tilt, is detected instantaneously with a suitable measuring system.

[0189] The advantage of this arrangement is that now the photometer no longer needs to move on a linear axis to adjust the elevation angle in the coupled cylindrical coordinate system, but can be done by tilting the vehicle forward or backward. However, the above-mentioned drawback of the vehicle tilting towards the chassis must be detected and corrected. For example, this can be done by cameras mounted on the left and right sides of the vehicle, which measure the marked points attached to the vehicle body, thereby detecting the true tilt angle of the vehicle relative to the horizontal zero position, independent of the vehicle chassis, for example, spring deflection or tire pressure can distort the vertical angle.

[0190] As Figure 1 shown, the measurement is carried out by rotating the platform 3 on which the tilted vehicle 1 is placed, such that the headlight moves on an arc around the center point of the rotating device. This measurement can be repeated for different tilt angles.

[0191] In this exemplary embodiment, the measurement geometry is described by a spherical coordinate system, the origin of which moves on the sphere. This is because the vehicle 1 tilts about two mutually perpendicular axes on the turntable, resulting in measured values on the sphere corresponding to Figure 9 the inner spherical coordinate system, which represents the first coordinate system. Now the corresponding measured values determined for different emission directions must be converted into the coordinates of an external second coordinate system, where the radiation center of the radiation source is located at the origin of the coordinates of the second coordinate system. The conversion is carried out by a coordinate transformation between two coupled spherical coordinate systems, where, as described in the first equation, the absolute value is also modified by the distance law and the angle of incidence relative to the photometer.

[0192] The described invention enables an objective metrological evaluation of the lighting equipment of a vehicle in the installed state in the laboratory. Compared with the methods carried out outdoors and / or during driving (gewonnen), the advantage is that the influence of the road (reflection, dry or wet conditions) as well as the influence of residual brightness or atmospheric effects can be excluded. On the other hand, the described invention enables a large pre-assembled optical functional component to be eccentrically positioned on a goniometer and the measurement results to be converted into the reference system of the test object by a bijective, i.e., one-to-one reversible (ein-eindeutig umkehrbar) mapping.

[0193] The method according to the invention with an eccentrically arranged radiation source (which provides the optical function to be evaluated) enables the characteristic quantity to be determined to be detected in a coordinate system in which the radiation center of the radiation source is located at the origin of coordinates, although the radiation source is eccentrically arranged. One of the advantages of this method is that it is not necessary to move the radiation source to be measured to the origin of coordinates of the goniometer by moving the vehicle. On the one hand, this brings a spatial advantage, and on the other hand, it ensures that the vehicle to be measured is in a defined position, or if the turntable is additionally combined with a roller test bench, it ensures defined driving conditions.

[0194] It should be noted that in the case of an eccentrically arranged radiation source, the transformation of the described coordinate system can in principle be carried out in any situation of goniometric radiation measurement, even in a measurement arrangement without using a turntable according to Figure 1 and for goniometric radiation measurement of a component with an eccentrically arranged radiation source in a different way, for example by rotating the component around two axes arranged perpendicular to each other (e.g., with the aid of a robot).

[0195] It should be understood that the present invention is not limited to the above embodiments and various modifications and improvements can be made without departing from the concept described herein. It should also be noted that any of the described features can be used alone or in combination with any other feature, provided that they are not mutually exclusive. The present disclosure extends to and includes all combinations and sub-combinations of one or more of the features described herein. If ranges are defined, they include all values within these ranges and all sub-ranges falling within a range.

Claims

1. A method for direction - related measurement of at least one optical - technical or radiometric characteristic quantity of a light radiation source (2) installed in an object (1), wherein, The method includes: - arranging the object (1) on a turntable (3) having a rotation axis (31), wherein the rotation axis (31) of the turntable (3) defines a first coordinate system, and the origin (O) of the first coordinate system is formed by the intersection of the surface (32) of the turntable (3) and the rotation axis (31), and its spatial axis coincides with the rotation axis (31); - wherein the object (1) is arranged on the turntable (3) in such a way that the radiation center of the light radiation source (2) is spaced apart from the origin (O) of the first coordinate system; - determining the position of the radiation center of the light radiation source (2) relative to the origin (O) of the first coordinate system as a relative position; - performing angular radiation measurement, which is carried out in the first coordinate system and includes rotation of the object (1) about an axis. The object (1) rotates around the rotation axis (31) of the turntable (3) starting from an initial position (A1) on the turntable (3), and the rotation axis (31) of the turntable (3) constitutes the axis of the angular radiation measurement. For a plurality of emission directions, direction-related detection of the measured quantity of the light radiation source (2) is carried out, wherein the emission directions defined in the first coordinate system respectively match the measured values of the measured quantity; - calculating the measured quantity for a plurality of emission directions in a second coordinate system according to the values of the measured quantity determined in the first coordinate system and detected in a direction-related manner and the relative position. In the second coordinate system, the radiation center of the light radiation source (2) is located at the origin of the coordinate system; - wherein the measured quantity is equal to the characteristic quantity to be measured, or the characteristic quantity to be measured is calculated from the measured quantity.

2. The method according to claim 1, characterized in that, The object (1) is an automobile or a component, wherein the light radiation source (2) is installed in the automobile or the component, and the automobile or the component is installed on the turntable (3) in such a way that the radiation center of the light radiation source (2) is spaced apart from the origin (O) of the first coordinate system.

3. The method according to claim 1 or 2, characterized in that, The turntable (3) rotates step by step.

4. The method according to claim 1 or 2, characterized in that, The turntable (3) rotates continuously while detecting measured values at defined angles.

5. The method according to claim 1 or 2, characterized in that, The geometric center of the radiation beam is defined as the radiation center of the light radiation source (2), and the radiation beam passes through a closed glass plate that separates the light radiation source (2) from the environment.

6. The method according to claim 1 or 2, characterized in that, The direction-related measured quantity in the second coordinate system is calculated according to the direction-related detected values of the measured quantity in the first coordinate system, which is achieved by mapping the coordinates of the values detected in the first coordinate system to the corresponding coordinates in the second coordinate system.

7. The method according to claim 1 above, characterized in that, In addition to the rotation of the object (1) on the turntable (3), the angular radiation measurement further includes detecting the measured quantity by means of one or more sensors (4) along a straight line according to the position along the straight line.

8. The method according to claim 7, characterized in that, Angular radiation measurements are carried out using the said sensor (4), which moves along the said straight line and records measurement values of the emitted radiation for defined positions on the said straight line.

9. The method according to claim 7 or 8, characterized in that, The illuminance is measured as the said measurement quantity, and the luminous intensity is calculated from the said illuminance as the said characteristic quantity to be measured of the said light radiation source (2), and the calculation is carried out using the following formula: where, I is the luminous intensity, E is the measured illuminance, d is the distance between the light radiation source and the sensor, and H corresponds to the azimuth angle φ, and V is equal to 90° minus the polar angle θ.

10. The method according to claim 7 or 8, characterized in that, The said first coordinate system is a cylindrical coordinate system. In the first step, the coordinates of the detected values in the said first coordinate system are transformed to another cylindrical coordinate system with the radiation center of the said light radiation source (2) located at its origin, and in the second step, they are transformed to a spherical coordinate system with the radiation center of the said light radiation source (2) at the origin of the said spherical coordinate system, where the said spherical coordinate system is the said second coordinate system.

11. The method according to claim 10, characterized in that, For each emission direction, the azimuth angle (H) and elevation angle (V) of the position (P) of the said sensor in the said second coordinate system are calculated from the rotation angle (D) of the said turntable (3) in the said first coordinate system and the height position (S) of the said sensor (4) along the said straight line, and the value of the said measurement quantity measured by the said involved sensor (4) is matched to the emission direction defined by the said azimuth angle (H) and the said elevation angle (V), where the value of the said measurement quantity is corrected by the distance and the angle of incidence relative to the said sensor (4) in order to obtain the said characteristic quantity from the said measurement quantity.

12. The method according to any one of claims 7 or 8, characterized in that, The rotation axis (31) of the said turntable (3) extends vertically, and the said straight line (40) extends vertically, and the said measurement quantity is detected along the said straight line (40).

13. The method according to claim 7 or 8, characterized in that, In addition to the rotation of the said object (1) on the said turntable (3) and the detection of the said measurement quantity along the said straight line (40) according to the position along the said straight line (40), the said angular radiation measurement also includes the detection of the said measurement quantity along a second straight line (41) according to the position along the said second straight line (41), where the said straight line (40) and the said second straight line (41) extend parallel to each other and are arranged at different distances relative to the origin (O) of the said first coordinate system.

14. The method according to claim 1, characterized in that, In addition to the rotation of the said object (1) on the said turntable (3), the said angular radiation measurement also includes the detection of the said measurement quantity by means of a position-fixed camera (7), where for at least two positions of the said turntable (3), the radiation emitted by the said light radiation source (2) is reflected in a diffuse manner on a reflective measurement wall (5) and detected by the said camera (7) as a brightness distribution on the said measurement wall, and the brightness distribution detected by the said camera (7) is transformed into a brightness distribution in the said second coordinate system by means of a coordinate transformation, where the said brightness distribution is the said measurement quantity.

15. The method according to claim 14, characterized in that, The said measurement wall (5) is arranged in the far field of the light distribution of the said light radiation source (2).

16. The method according to claim 14 or 15, characterized in that, Another sensor (8) is directly irradiated and the signal detected by the said another sensor (8) is used to calibrate the camera (7).

17. The method according to claim 1, characterized in that, In addition to the rotation of the object (1) on the turntable (3), the goniometric radiometric measurement further includes tilting of the turntable (3) or the object (1) about an axis perpendicular to the rotation axis (31), wherein the object (1) is rotated at a plurality of tilt angles, and the measured quantity is detected for each combination of the rotation angle and the tilt angle.

18. The method according to claim 17, characterized in that, A position-fixed sensor is used for the goniometric radiometric measurement, and the position-fixed sensor records the measured values of the emitted radiation for each combination of the rotation angle and the tilt angle.

19. The method according to claim 17 or 18, characterized in that, The calculation of the direction-dependent measured quantity in the second coordinate system from the values of the direction-dependent measured quantity detected in the first coordinate system is achieved by mapping the coordinates of the values detected in the first coordinate system onto the corresponding coordinates in the second coordinate system, wherein the second coordinate system is a spherical coordinate system with the origin moving on the sphere.

20. A method for performing a direction-dependent measurement of at least one optical-technical or radiometric characteristic quantity of a light radiation source (2) installed in an object (1), wherein, The method includes: - arranging the object (1) at or on a holding element, the holding element being provided and designed to rotate the object (1) about a first axis and a second axis perpendicular to the first axis, wherein the object (1) is arranged at the holding element such that the radiation center of the light radiation source (2) is located outside the origin (O) of the first coordinate system formed by the first axis and the second axis, - determining the position of the radiation center of the light radiation source (2) relative to the origin (O) of the first coordinate system as a relative position, - performing a goniometric radiometric measurement, which includes the rotation of the object (1) about the two axes, wherein the goniometric radiometric measurement is performed in the first coordinate system, wherein for a plurality of emission directions, the direction-dependent detection of the measured quantity of the light radiation source (2) is performed, and wherein the emission directions defined in the first coordinate system respectively match the measured values of the measured quantity, - calculating the measured quantity for a plurality of emission directions in a second coordinate system based on the values of the direction-dependent measured quantity detected in the first coordinate system and the relative position, in the second coordinate system, the radiation center of the light radiation source (2) is located at the coordinate origin, - wherein the measured quantity is equal to the characteristic quantity to be measured, or the characteristic quantity to be measured is calculated from the measured quantity.

21. A goniometric radiometer for performing a direction-dependent measurement of at least one optical-technical or radiometric characteristic quantity of a light radiation source (2) installed in an object (1), wherein, The goniometric radiometer includes: - a turntable (3) having a rotation axis (31), wherein the rotation axis (31) of the turntable (3) defines a first coordinate system, the origin (O) of the first coordinate system is formed by the intersection of the surface of the turntable (3) and the rotation axis (31), and the spatial axis of the first coordinate system coincides with the rotation axis (31), and wherein the turntable (3) is arranged to carry the object (1) such that the radiation center of the light radiation source (2) is spaced apart from the origin (O) of the first coordinate system, - at least one sensor (4), the sensor being designed and arranged to measure the measured quantity of the light radiation source (2). - wherein the turntable (3) and the at least one sensor are designed to perform goniometric radiation measurement in the first coordinate system, the goniometric radiation measurement including the rotation of the object (1) about the rotation axis (31) of the turntable (3), wherein, for a plurality of emission directions, the measurement quantity is detected direction-dependently, and wherein the emission directions defined in the first coordinate system respectively match the measured values of the measurement quantity, - a calculation unit (6), which is arranged and designed to calculate the measurement quantity for a plurality of emission directions in a second coordinate system, in which the radiation center of the light radiation source (2) is located at the origin of the coordinate system, and this calculation is performed based on the position of the radiation center of the light radiation source (2) relative to the origin of the first coordinate system and based on the values of the measurement quantity detected direction-dependently in the first coordinate system. - wherein the calculation unit (6) is further arranged and designed to calculate the characteristic quantity to be measured based on the measurement quantity, provided that the measurement quantity is not yet the characteristic quantity to be measured.

22. The goniometric radiometer according to claim 21, characterized in that, The goniometric radiometer is a goniometric radiometer of type 3, wherein the at least one sensor detects the measurement quantity along a straight line according to the height position (S) along the straight line.

23. The goniometric radiometer according to claim 21, characterized in that, The goniometric radiometer further comprises: - a measurement wall (5) having a diffusely reflecting reflectivity, which reflects the light emitted by the light radiation source (2), - a camera (7) arranged in a position-fixed manner, which has a two-dimensional sensor chip, wherein the pixels of the sensor chip form the at least one sensor, - wherein the camera (7) is arranged and designed such that the camera detects the light reflected on the measurement wall (5) for at least two positions of the turntable (3), wherein the reflected light is imaged on the sensor chip of the camera (7), and wherein the reflected light is detected by the camera (7) as the brightness distribution on the measurement wall (5), - wherein the calculation unit (6) is designed to convert the brightness distribution detected by the camera (7) into a brightness distribution in the second coordinate system by means of a coordinate transformation.

24. The goniometric radiometer according to claim 21, characterized in that - the at least one sensor comprises a position-fixed sensor, - the turntable (3) is designed such that in addition to rotating about the rotation axis (31), the object (1) arranged thereon is tilted about an axis perpendicular to the rotation axis (31), or the object (1) is arranged to be tiltable about the axis perpendicular to the rotation axis, - wherein the turntable (3) or the object (1) and the at least one sensor cooperate in the goniometric radiation measurement such that the object (1) rotates at a plurality of tilt angles in the goniometric radiation measurement, and the position-fixed sensor detects the measurement quantity for each combination of the rotation angle and the tilt angle.

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