Method and gonioradiometer for the direction-dependent measurement of at least one illumination or emission characteristic variable of a light source attached to an object

Abstract

A method and gonioradiometer for direction-dependent measurement of at least one photometric or radiometric characteristic of an optical radiation source. The radiation direction of the photometric or radiometric characteristic is described using a system of planes (A, B, C), whose planes intersect at a line of intersection passing through the radiation center of the radiation source. The radiation direction of the photometric or radiometric characteristic is also described using radiation angles (α, β, γ) that specify the radiation direction (α, β, γ) in the plane of consideration. The sensor or the radiation source is attached to a robot with multiple joints. The robot is configured to rotate precisely around only one of the multiple axes during the measurement process. During the measurement process, measurements are obtained for different radiation angles (α, β, γ) in the plane of consideration in the system of planes (A, B, C), or for different surfaces at the radiation angles (α, β, γ) under consideration.

Description

Technical Field

[0001] The present invention relates to a method and a goniophotometer for the direction-dependent measurement of at least one illumination or radiation characteristic of a light source attached to an object.

[0002] Conventionally, goniophotometers have been used for the measurement of illumination and the characteristics of the radiation of lamps and lights. A goniophotometer is a mechanical optical measurement system that can determine the direction dependence of the quantities used to describe the radiation of light. For example, depending on the sensor used or the head of the measuring instrument, the photometric distribution or color distribution of the light source may be determined. The light source or radiation source is arranged such that its optical center becomes the center of the goniophotometer and the origin of the spherical coordinate system. In this case, the measured values of the illumination or radiation characteristics can be measured angularly, that is, for all directions, by rotating the light source or radiation source or by continuously moving the sensor over different angular ranges. By evaluating for individual directions and / or by integrating the measurement results over a partial range or the entire solid angle of the distribution, the illumination or radiation characteristics of the light source are obtained.

[0003] The illumination or radiation characteristic, for example the luminous intensity, is a quantity that depends on the direction, and its radiation direction is generally specified by two angles in the spherical coordinate system associated with the light source. The description by specific plane systems called the A-plane system, B-plane system, and C-plane system has become widespread. These plane systems are described in "Measurement of Absolute Photometric Distribution", CIE Document No. 70 (1987), CIE Central Bureau, ISBN 3900734054.

[0004] Similarly, certain types of goniophotometers defined in CIE document No. 70 (1987) have been proven to be actually successful. In types 1.1 to 1.3 goniophotometers, when the sensor is in a stable position, the light source rotates during measurement. In type 3 goniophotometers, the radiation source rotates about an axis, and the sensor moves along a straight line extending parallel to the rotation axis. In this case, the light source or radiation source is arranged such that its optical center of gravity or radiation center of gravity becomes the center of the goniophotometer.

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is an increasing interest in recording the lighting and radiation characteristics of lamps and lights in the state encountered during use, that is, in the mounted state. In this case, one of the important applications is the measurement of the quality of the headlamp lighting and / or the light-emitting signal function of a vehicle in the mounted state. Such tests are different from the conventional tests on the light-emitting components (headlamps, lights) of a vehicle in that the effects and tolerances caused by the mounting of these components on the vehicle are also recorded. The said effects are particularly due to the following. - Deviations from the intended mounting position, for example due to tolerances associated with the manufacture of the body. - Displacements from the horizontal of the vehicle, for example caused by tolerances in the chassis, particularly the depth of insertion of the springs, and by the influence of the load (number of passengers, fuel, i.e., the tank is full or empty) or the air pressure of the tires. - And the quality of the headlamp adjustment at the end of vehicle manufacture.

[0006] The object of the present invention is to provide a method and a goniophotometer for the direction-dependent measurement of at least one illumination or emission characteristic of a light radiation source. Thereby, it is possible to record the characteristics of the radiation source in the mounting state where the state of the radiation source is the mounting state. According to the present invention, the above object is achieved by a method having the characteristics in claim 1, a method having the characteristics in claim 20, and a goniophotometer having the characteristics in claim 21. The configuration of the present invention is specified in the dependent claims.

Means for Solving the Problem

[0007] Accordingly, a first aspect of the present invention relates to a method for direction-dependent measurement of at least one illumination or emission characteristic of a light radiation source attached to an object, the method including the following steps (not necessarily executed in a specific order).

[0008] The object is placed on a turntable having a rotation axis, and the rotation axis of the turntable defines a first coordinate system. The origin of the first coordinate system is formed, for example, by the intersection of the surface of the turntable having the rotation axis and the spatial axis that coincides with the rotation axis. In this case, the object is placed on the turntable such that the radiation center of gravity of the light radiation source is separated from the origin of the first coordinate system. Thus, when the object is, for example, a vehicle, the entire vehicle is placed on the turntable, and the radiation center of gravity of the headlamp is not located on the axis of the turntable. A goniometric measurement including the rotation of the object about a certain axis is performed. The goniometric measurement is performed in the first coordinate system, and the object on the turntable is rotated about the rotation axis of the turntable starting from the initial position, and the rotation axis of the turntable constitutes the axis of the goniometric measurement. In this case, the rotation axis of the turntable may extend in the vertical direction, but this is not essential. During the goniometric measurement, a direction-dependent recording of the measured quantity of the radiation source is performed for a number of radiation directions or a number of measurement angles. For each radiation direction defined in the first coordinate system, a measured value of the measured quantity is assigned. For example, for each radiation direction defined in the first coordinate system, a value of the measured quantity recorded by the sensor is assigned respectively. In this case, the goniometric measurement is performed in the first coordinate system. Further, the position of the radiation center of gravity of the light radiation source is determined, for example, at the initial position with respect to the origin of the first coordinate system. This can be done before starting the goniometric measurement. Here, it is intended to calculate the measured quantity for a number of radiation directions in a second coordinate system where the radiation center of gravity of the light radiation source is at the origin of the coordinate system. This is performed based on the measured value of the measured quantity recorded direction-dependently in the first coordinate system and the relative position (i.e., the position of the radiation center of gravity of the light radiation source with respect to the origin of the first coordinate system). Thus, the spatial distribution of the measured quantity is converted from the distribution measured in the first coordinate system to a spatial distribution centered on the radiation center of gravity of the light radiation source. The measured quantity may already be a characteristic quantity to be measured, or the characteristic quantity to be measured may be calculated from the measured quantity.

[0009] For example, when the measured quantity is the illuminance measured by a sensor, the luminous intensity of the radiation source as the feature quantity to be measured can be derived therefrom. This is performed by correction regarding the incident distance and incident angle with respect to the sensor according to the configuration described in claim 9.

[0010] By the method executed above, even if the radiation source is not located at the origin of the coordinate system in which goniometric measurement is performed, it is possible to provide information regarding the spatial distribution of the feature quantity of the radiation source.

[0011] Therefore, the present invention is based on the concept of performing goniometric measurement with the radiation source initially displaced from the center without placing the feature quantity to be recorded or the function to be tested at the center of the axis of the goniometer.

[0012] By knowing the arrangement of the radiation source displaced from the center on the turntable, each measurement angle can be calculated within the system of the object to be tested or the radiation source. This conversion is performed based on the coordinate conversion between each coordinate system. In other words, the present invention proposes that the light distribution or feature quantity distribution of the radiation source is determined by two combined coordinate systems. The goniometric measurement with the radiation source displaced from the center is performed in the first coordinate system, and the distribution of light or the distribution of the feature quantity to be measured is calculated in the second coordinate system.

[0013] In this case, the selection of the two combined coordinate systems is made 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. That is, there exists a function that performs a unique mathematical calculation for converting from one coordinate system to the other, and there also exists a unique inverse function for returning from the second coordinate system to the first coordinate system.

[0014] The present invention is related to the advantage that even if the radiation source is not at the origin of the radiation measurement, the feature quantity to be measured of the mounted radiation source can be recorded depending on the direction and can be accurately and quantitatively evaluated. This enables measurement considering the influence and tolerance due to the attachment of the radiation source to an object such as a vehicle.

[0015] As already mentioned, according to one configuration of the present invention, the object to be observed is an automobile or a vehicle. The entire automobile or vehicle is placed on a turntable. In this case, different attached radiation sources, for example, left headlamp light, right headlamp light, can be continuously measured in the same way as signal lamps, for example, direction indicator lamps. Naturally, the light of the headlamp can be measured for various operating modes such as low beam, high beam, parking light, etc. However, the present invention can also be carried out for spatially extended components that are arranged on the turntable and attached off-center with a radiation source.

[0016] According to one configuration of the present invention, the rotation axis of the turntable extends in the vertical direction. This is recommended for the simple reason that the weight of the object can be evenly distributed on the turntable. However, in principle, it can also be considered in the same way that the turntable is arranged with a certain inclination in space such that the rotation axis of the turntable forms an angle with respect to the vertical direction.

[0017] Naturally, since there are an infinite number of radiation directions, it is not possible to record the characteristic quantities for each radiation direction. Instead, a specific grid of radiation directions is recorded, and each of the specific grids represents a specific solid angle, that is, a specific part of the total solid angle. To define the radiation directions according to such a grid, it is sufficient for the turntable to be rotated stepwise and the rotation settings of the turntable to correspond to the radiation directions respectively. Alternatively, the turntable rotates continuously, and at specific instants or defined angles, the measured values corresponding to the specific radiation directions are recorded respectively.

[0018] According to one configuration of the present invention, in addition to the rotation of an object on a turntable, the gonioradiometric measurement includes recording a feature along a straight line as a function of the position along the straight line. In the above configuration, the gonioradiometer is a type 3 gonioradiometer, the radiation source is rotated about an axis (offset from the center of the turntable on the turntable), and the sensor is moved along a straight line.

[0019] Therefore, according to one configuration, for this purpose, a sensor that moves along a straight line and acquires a measurement value of the radiation emitted at a specified position on the straight line is used for gonioradiometric measurement. In this case, the sensor is preferably arranged on a vertical line extending parallel to the rotation axis of the turntable. In that case, the recording of the measured quantity is performed along a vertically extending line, and as a result, in combination with the rotation, an orthogonal grid is included. However, in principle, the sensor can move on a line extending arbitrarily in space. Alternatively, instead of one sensor, it is also possible to provide a plurality of sensors arranged along the straight line, thereby eliminating the need for the movement of the sensor.

[0020] The selection of this type 3 gonimeter has the advantage that there is no need to tilt the object or vehicle around a horizontal axis. If such a tilt occurs, the force applied to the vehicle's suspension is generated by gravity, and the said force affects the orientation related to the vehicle's design from a virtual horizontal direction.

[0021] Conventionally, in order to be able to measure the lighting function with this type of gonimeter attached to a vehicle, that is, without using two coupled coordinate systems, the light source to be measured (low beam, direction indicator signal, etc.) is placed at the center of the rotation axis, and after firmly attaching it to the vehicle, the entire vehicle needs to be moved laterally and fixed again. In addition to mechanical problems, this also requires even larger space requirements, so the dimensions of the measurement room also need to be even larger.

[0022] Therefore, according to this aspect of the present invention, the present invention proposes to arbitrarily position a vehicle on a rotating device without impairing the accuracy, and then accurately measure the position of a light-emitting function that is a measurement object with respect to the rotation axis.

[0023] The plane of the turntable on which the object or vehicle is placed represents the plane of the road, and all lighting measurement quantities are associated with this plane in further evaluation, enabling the lighting situation generated by the vehicle on the road lane to be confirmed.

[0024] According to an alternative embodiment, illuminance is measured as the measurement quantity, and luminous intensity as a characteristic quantity to be measured of the radiation source is calculated from the illuminance using the following formula.

Equation

[0025] Therefore, to calculate the luminous intensity from the measured illuminance, for example, it is necessary to know the distance d between the light source and the sensor, and the angles H and V. The above formula assumes that the sensor is oriented parallel to the X-axis (H = 0). In the above distance correction, not only the distance between the radiation source and the sensor but also the fact that the intensity of the light received by the sensor surface or the photometer of the sensor decreases when oblique light is incident is considered.

[0026] According to an alternative embodiment, for this purpose, in addition to the rotation of the object on the turntable and the recording of the feature quantity along the straight line as a function of the position along the straight line, the gonioradiometric measurement includes the recording of the feature quantity along the second straight line as a function of the position along the second straight line. The first straight line and the second straight line extend parallel to each other and are arranged at different distances from the origin of the first coordinate system. In this case, it is preferable that the two lines, or straight axes, are arranged at different distances, for example, at 25 m and 5 m, without limitation in terms of generality. With such a configuration, not only the headlamp but also the signal function can be optimally measured in the installation on the vehicle.

[0027] It should be pointed out that the radiation center of gravity of the radiation source can in principle be defined in various ways. For example, the radiation center of gravity of the radiation source may be the midpoint of the coiled filament that emits light. Another possible method is to define the radiation center of gravity of the radiation source as the geometric center of gravity of the radiation beam passing through the closing plate that separates the radiation source from the surroundings. The closing plate is, for example, the lens of the headlamp from which the light beam is emitted. In this case, the radiation center of gravity defined in this way is generally indicated by the mark in the closing plate on the manufacturer's side.

[0028] According to another configuration of the present invention, the calculation of the feature quantity depending on the direction in the second coordinate system from the value of the measured quantity recorded depending on the direction in the first coordinate system is performed by corresponding the coordinates of the measured values recorded in the first coordinate system to the corresponding coordinates in the second coordinate system.

[0029] In principle, in this case, any desired coordinate system such as a Cartesian coordinate system, a cylindrical coordinate system, a spherical coordinate system, etc. can be used. For example, in the spherical coordinate system, each radiation direction is defined by an azimuth angle and a polar angle.

[0030] According to an alternative embodiment having a rotating table and a linear axis, the first coordinate system is a cylindrical coordinate system, and the coordinates of the values recorded in the first coordinate system are, in a first step, converted into another cylindrical coordinate system in which the radiation center of gravity of the radiation source is located at the origin, and in a second step, converted into a spherical coordinate system in which the radiation center of gravity of the radiation source is located at the origin. The spherical coordinate system becomes the second coordinate system.

[0031] Therefore, the conversion to the spherical coordinate system with the radiation center of gravity of the radiation source as the origin is performed by performing intermediate calculations of the coordinates in the intermediate coordinate system. However, this is only one embodiment. In principle, a direct conversion may be performed between the first coordinate system and the second coordinate system. In this case, any appropriate mathematical method can be used.

[0032] According to the above alternative embodiment, for each radiation direction, the position of the sensor in the first coordinate system is calculated from, on the one hand, the rotation angle D of the rotating plate and, on the other hand, the height S of the sensor. The azimuth angle H and the elevation angle V of the sensor position in the second coordinate system are calculated therefrom, and the value of the measured quantity measured by the sensor in question is assigned to this radiation direction defined by the azimuth angle and the elevation angle. In addition, in this case, in order to obtain a characteristic quantity from the measured quantity, in particular to calculate luminous intensity from illuminance, each measured value is corrected by the incident distance and the incident angle with respect to the sensor.

[0033] According to another configuration, the goniometric measurement is performed not by a type 3 goniometer, but instead by using a camera. In this case, in addition to the rotation of the object on the turntable, the goniometric measurement includes the recording of the measured quantity by a statically arranged camera, the radiation emitted from the radiation source reflected by the diffuse reflection type measurement wall, i.e., the non-directional reflection, and the recording of the non-directional reflection by the camera as the luminance distribution on the measurement wall in at least two settings of the turntable. In this case, the luminance distribution recorded by the camera is converted into the luminance distribution in the second coordinate system using coordinate transformation. The luminance distribution in this case constitutes the measured quantity.

[0034] Such a measuring device is basically based on a goniometric measuring device as described in WO 2016 / 116300 A1.

[0035] According to said alternative embodiment, in order to be able to record the entire angular range with a single luminance image, goniometric measurement only requires the rotation movement of the vehicle and the measurement wall measurement system by said camera. The luminance distribution measured on the wall by the camera is then converted into the luminous intensity distribution of the headlamp using coordinate transformation.

[0036] In this case, the luminance distribution represented on the measurement wall in the setting of the object on the turntable already defines a relatively large solid angle. That is, two-dimensional measurement values for a number of radial directions are recorded by the objective lens of the camera within the solid angle defined by the measurement wall. If the measurement wall is high enough to completely image the vertical distribution of the radiation source in the far field, the polar angle dependence of the feature to be measured may already be determined by the representation or luminance distribution on the measurement wall.

[0037] By rotating the turntable, other solid angles with other azimuth angles are displayed on the measurement wall. Depending on the width of the measurement wall, the luminance distribution is recorded for at least two settings of the turntable (otherwise, goniometric measurement is not performed). The overall light distribution is composed by connecting individual solid angle grids.

[0038] The combined coordinate system is also used in the alternative embodiment with a camera. That is, the conversion of the wall coordinates, where the luminance camera checks the measurement values, to spherical coordinates in the reference system with respect to the headlamp changes with the rotation of the headlamp in space. If the coordinates of the headlamp are known as a function of the angle of the rotating device, it is again possible to find a bijective mapping that calculates the light distribution in the reference system of the test object from the angle of the rotating device and the height of the headlamp. Then, a plurality of partial angular ranges can be combined to form the overall angular distribution.

[0039] The advantages of the above method are that by combining the rotation of the vehicle and the measurements with the camera, data can be acquired faster than the speed possible by sequential grid measurements based on sensors or photometers, and there are no requirements simultaneously required for the position of the headlamp on the rotating plate. The position of the headlamp on the rotating plate only needs to be determined accurately.

[0040] According to one configuration, the measurement wall is arranged at a distance in the far field of the light distribution of the radiation source, that is, a distance at which the radiation source can be regarded as approximately a point light source. For example, the initial position of the measurement wall is at a distance of 25 m from the radiation source.

[0041] According to another configuration, the light of the radiation source further directly irradiates another sensor, and the signal recorded by the sensor is used for the calibration of the camera. Since the measurement uncertainty of the camera measurement is significantly larger than the measurement uncertainty of the sensor measurement (usually by a photometer), the data acquired by the camera may be corrected point by point using the sensor. The above-mentioned another sensor may be a sensor arranged in front of or laterally adjacent to the measurement wall. Moreover, it is also possible to arrange the sensor behind the measurement wall and irradiate the sensor through the opening of the measurement wall.

[0042] The advantages of the correction by using an additional sensor are that in addition to reducing the measurement uncertainty, it is also realized by the sensor or photometer that the measured values are traceable, and the combination of the wall camera for measurement does not need to be absolutely calibrated.

[0043] According to another configuration of the present invention, in addition to the rotation of the object on the turntable, the goniometric measurement includes the inclination of the turntable or the object around an axis perpendicular to the rotation axis, the rotation of the object on the turntable about a number of inclination angles, and the recording of the measured quantity for each combination of the rotation angle and the inclination angle. The measured quantity is recorded based on the goniometric measurement on the spherical surface around the radiation center of the radiation source.

[0044] In particular, the object is further inclined with respect to the horizontal axis (by tilting the turntable or the object). In this case, a static sensor for acquiring the measured value of the emitted radiation may be used for gonioradiometric measurement for each combination of the rotation angle and the tilt angle.

[0045] Whichever of the tilt angle of the turntable or the tilt angle of the vehicle body (when the object in which the radiation source is installed is a vehicle) is recorded, the angle at which the turntable or the object is tilted is, in this case, recorded using an appropriate measurement system.

[0046] In the above arrangement, in the case of gonioradiometric measurement, there is an advantage that it is not necessary to move the sensor on the linear axis to measure the elevation angle in the combined coordinate system. Instead, the elevation angle can be measured in the combined coordinate system by tilting the vehicle forward or backward. In this way, the photometer can be configured to be fixed, which is advantageous, for example, when the ceiling height is limited.

[0047] However, in this alternative embodiment, it is necessary to record and correct the disadvantages described when introducing the tilt of the vehicle on the chassis. This is done, for example, using cameras attached to the left and right of the vehicle, measuring the marked points attached to the vehicle body by the cameras, and thus recording the actual tilt angle of the vehicle with respect to the horizontal neutral position without being affected by the chassis, such as spring compression or tire air pressure, which may impair the vertical angle.

[0048] In this exemplary embodiment, the measurement is performed by combining the rotation of the platform on which the tilted vehicle is installed and the tilt, and the headlamp is made to move on an arc tilted by the tilt angle around the midpoint of the device that causes the rotation. However, in this case, the arrangement used for the measurement is described by the combination of the origin on the spherical surface and the spherical coordinate system.

[0049] According to an alternative embodiment, for this purpose, the calculation of the measurement quantity that depends on the direction in the second coordinate system from the value of the measurement quantity recorded depending on the direction in the first coordinate system is performed by making the coordinates of the value recorded in the first coordinate system correspond to the corresponding coordinates in the second coordinate system. The second coordinate system is a spherical coordinate system, and its origin moves on the spherical surface.

[0050] According to a second aspect of the invention, the invention relates to a method for measuring at least one illumination or radiation feature quantity that depends on the direction of a light radiation source attached to an object, the method comprising the following steps. - Place the object on or on the surface of a holding element, the holding element being intended and configured to rotate the object around a first axis and around a second axis perpendicular to the first axis, and the object is placed on the surface of the holding element such that the radiation center of gravity of the light radiation source is outside the origin of the first coordinate system formed by the first axis and the second axis. - Determine the position (relative position) of the radiation center of gravity of the light radiation source with respect to the origin of the first coordinate system. - Perform a goniometric measurement including rotation of the object around two axes in the first coordinate system. - Record the measurement quantity of the radiation source depending on the direction by goniometric measurements for a plurality of radiation directions, and assign a measurement value of the measurement quantity to each radiation direction defined in the first coordinate system. - Calculate the measurement quantity that depends on the direction for a plurality of radiation directions in the second coordinate system where the radiation center of gravity of the light radiation source is located at the coordinate origin from the value of the measurement quantity recorded depending on the direction confirmed in the first coordinate system and at the relative position. - Here, the measurement quantity is the same as the feature quantity to be measured, or the feature quantity to be measured is calculated from the measurement quantity.

[0051] Here, the radiation center of gravity of the radiation source is also located outside the origin of the coordinate system in which the measurement is performed, and subsequent conversion into a second coordinate system is then carried out. However, this method is different from the method according to claim 1 in that the object is not placed on a turntable, but instead the object is rotated about two axes according to a conventional gonioradiometric measurement using a type 1 gonioradiometer. In this case, the object is arbitrarily placed in space and is held, for example, by a robot as a holding element capable of rotating the object about a plurality of axes.

[0052] A further aspect of the invention relates to a gonioradiometer for direction-dependently measuring at least one illumination or radiation characteristic of a light radiation source attached to an object, said gonioradiometer comprising the following configuration. - A turntable having a rotation axis, wherein the rotation axis of the turntable defines a first coordinate system, and the origin of the first coordinate system is formed by the intersection of the surface of the turntable having the rotation axis and the spatial axis that coincides with the rotation axis, and the turntable is intended to receive the object such that the radiation center of gravity of the light radiation source is separated from the origin of the first coordinate system. - At least one sensor configured and intended to measure a measured quantity. - Here, the turntable and the at least one sensor are configured to perform a gonioradiometric measurement, said gonioradiometric measurement including the rotation of the object about the rotation axis of the turntable in the first coordinate system, the measured quantity recorded by gonioradiometric measurements for a number of radiation directions, and the radiation direction defined in the first coordinate system to which each measured value of the measured quantity is assigned. - A calculation unit for calculating the measured quantity in a number of radiation directions in a second coordinate system in which the radiation center of gravity of the light radiation source is located at the origin of the coordinate system from the position of the radiation center of gravity of the light radiation source with respect to the origin of the first coordinate system and the value recorded depending on the direction of the measured quantity confirmed in the first coordinate system. - If the measured quantity is not yet the characteristic quantity to be measured, the calculation unit is further configured to calculate the characteristic quantity to be measured from the measured quantity.

[0053] Using such a goniometer, it is possible to execute the method according to claim 1. In particular, the goniometer may form a type 3 goniometer in which at least one sensor records the measured quantity along a straight line as a function of the position in the height direction along the straight line.

[0054] Using the goniometer according to the invention, in particular, the quality of the headlamp illumination or the light signal function of a vehicle can be evaluated in the mounted state. Such tests differ from conventional tests on vehicle lighting components (headlamps, lights) in that the effects and tolerances due to the mounting of these components on the vehicle are also recorded.

[0055] In some configurations of the present invention, the goniometer is intended and configured to execute a variation of the method specified in claims 2 to 18.

[0056] According to an alternative embodiment, the goniometer further includes the following. - A reflection measurement wall that performs diffuse reflection of reflecting the light emitted from the radiation source. - A camera that is arranged statically and immovably and has a two-dimensional sensor chip, and pixels of the sensor chip form at least one sensor. - The camera is arranged and configured to record the light reflected by the measurement wall for at least two settings of the turntable. The reflected light is imaged on the sensor chip of the camera, and the reflected light is recorded by the camera as the luminance distribution on the measurement wall. - The calculation unit is configured to convert the luminance distribution recorded by the camera into a luminance distribution in a second coordinate system by coordinate transformation.

[0057] According to another alternative embodiment, it is as follows. - At least one sensor includes a static sensor. - The turntable is configured to tilt an object placed on the turntable about an axis perpendicular to the axis of rotation in addition to rotation about the axis of rotation, or the object is disposed so as to be tiltable about such an axis. - During goniometric measurement, the turntable or the object and at least one sensor cooperate such that the object is rotated on the turntable during goniometric measurement with respect to the static sensor that records a characteristic quantity to be measured for each of a number of tilt angles and combinations of rotation angles and tilt angles.

[0058] It should be noted that the terms referred to below are defined as follows within the scope of the present disclosure.

[0059] The terms lighting and photometry may also include the term radiometry as long as characteristic quantities related to infrared (IR) or ultraviolet (UV) are measured. The term sensor includes all embodiments for measuring optical radiation (ultraviolet, visible, and infrared) in the wavelength range from 100 nm (UV-C) to 1 mm (IR-C). According to an exemplary embodiment, the sensor is provided as a photometer. The terms goniophotometer and goniometer are used synonymously when the light distribution of a lighting fixture is recorded by some sensor (photometry or radiometry). When referring to a goniometer, it always means all embodiments regardless of which sensor is used. The term vehicle includes all types of vehicles, particularly for transportation on roads, railways, in water, or in the air.

[0060] The following exemplary embodiments generally relate to a road vehicle (automobile) for transporting people individually. The term lighting fixture may include, in addition to headlamps for illuminating a road lane and signal devices of a vehicle, road lighting fixtures.

[0061] The present invention will be described in more detail below with reference to the diagrams of the drawings using some exemplary embodiments.

Brief Description of the Drawings

[0062]

Figure 1

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Figure 10

Modes for Carrying Out the Invention

[0063] Regarding the general background of the present invention, first refer to FIG. 10. FIG. 10 represents a spherical coordinate system with the expressions of the definitions of angles phi φ and theta θ. When there is a radiation source at the origin of such a spherical coordinate system, the illumination or radiation characteristics of the radiation source can be measured angularly, that is, omnidirectionally, by the rotation of the radiation source or the continuous movement of the sensor within the angular ranges of -180° ≤ φ ≤ 180° and -180° ≤ θ ≤ 180°. Therefore, the radiation direction can be defined by two angles φ and θ.

[0064] Generally, for a number of i of the radiation directions, or pairs of angles φ i , θ i specific luminous intensities, or other illumination or radiation characteristics of the radiation source are respectively assigned. The specific luminous intensity, or other illumination or radiation characteristics of the radiation source are measured by a sensor on the spherical surface or a partial region on the spherical surface, or are derived from the measured values recorded by performing goniometric measurements with the sensor.

[0065] In this way, the spatial distribution of the luminous intensity or the measured characteristics that define the radiation source is determined. Accurately determining the spatial distribution or accurately complying with the predetermined spatial values of the characteristics in question is very important, for example, in the case of vehicle headlamps.

[0066] In the measurement of vehicle headlamps, the headlamps (left and right respectively) can be first measured separately as individual objects using a conventional goniometer, and then the light distributions of the individual headlamps can be superimposed to simulate the light distribution on the road. Many elements are ignored in such component measurements by the goniometer, and in particular, the mounting state on the vehicle is not considered.

[0067] Figure 1 shows a first exemplary embodiment of a goniometer according to the present invention. The goniometer includes a turntable 3 that can rotate around a rotation axis 31. The turntable 3 is arranged on a platform 35. However, this is intended to be understood as merely an example. Alternatively, it is also possible to provide other means that can photometrically record the radiation belonging to the angular range below the plane of the turntable 3, for example, arranging the turntable 3 at a higher intermediate level.

[0068] At least in the area of the vehicle, the turntable 3 has a plane 32 that defines a first coordinate system together with the rotation axis 31. The origin of the first coordinate system is formed by the intersection of the surface 32 of the turntable 3 having the rotation axis 31 and the spatial axis (z-axis) that coincides with the rotation axis 31. In this case, the rotation axis 31 extends vertically.

[0069] A vehicle 1 is arranged on the turntable. The vehicle 1 typically has two front headlamps 2, and each front headlamp 2 is goniometrically measured with respect to its illumination or radiation characteristics. In this case, the vehicle 1 is arranged substantially centrally on the turntable 3 such that the headlamps 2 are spaced apart from the origin of the first coordinate system and the rotation axis 31 formed as described above.

[0070] To perform goniometric measurements, a vertically extending mast 40 is further provided, which can move the sensor 4 vertically between positions S in different height directions. The mast 40 extends starting from the floor surface at a level lower than the plane of the turntable 3 so as to be able to record the radiation emitted downward by the front headlamp 2.

[0071] Furthermore, a measurement wall 5 is shown, which diffusely reflects the emitted headlamp light. In the exemplary embodiments in question, the measurement wall 5 can be used for the visualization of the headlamp orientation and the visual check of the illuminance distribution generated by the headlamp, but is not relevant for the goniometric measurements performed. Let the shortest distance between the rotation axis 31 and the measurement wall 5 be r.

[0072] Both the mast 40 provided with the sensor 4 and the measurement wall 5 are located in the far field of the headlamps of the vehicle 1, and for example a distance of 25 m is selected.

[0073] The goniometer provided by the illustrated structure is a type 3 goniometer, and the rotation around the rotation axis, here the rotation axis 31 of the turntable 3, is combined with the movement of a sensor, here the sensor 4, along a vertical straight line. In this case, the measurement is carried out by the sensor 4 moving vertically for a specific rotation angle setting of the turntable 3 while acquiring a number of measured values corresponding to positions S in different height directions. The above is repeated for a number of rotation angle settings of the turntable 3. Alternatively, the turntable 3 moves to different turntable settings at a given height direction position S of the sensor 4, and this is repeated for different height direction positions S. During the measurement, only one radiation source is activated at a time, and in the exemplary embodiment, it is the left headlamp.

[0074] 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 partial range of this wavelength range. For example, the sensor is a photometer. The sensor 1 may be provided to perform partial or total filtering, and by being so provided, the sensitivity of the sensor becomes the same as the normal eye sensitivity curve. For example, the sensor 4 transmits a luminance value as an output value.

[0075] Sensor 4 moves along mast 40 to a position S in the height direction having a vertical distance from each other corresponding to an angular dimension of, for example, 0.05°, 0.1°, 0.15° or 0.2°. However, this is for the purpose of being understood as merely an example.

[0076] On the other hand, in the gonioradiometric measurement performed in this way, a procedure is adopted in which recordings dependent on the direction of the feature quantity to be measured for the radiation source (headlamp) are made for a number of radiation directions in the first coordinate system. Therefore, the spatial distribution of the illuminance or other feature quantity confirmed by the measurement does not provide information on the spatial distribution of the feature quantity in question regarding the radiation source.

[0077] In order to confirm the spatial distribution of the feature quantity in question regarding the radiation source, on the one hand, while considering the position of the radiation center of gravity of the light radiation source with respect to the origin of the first coordinate system, and on the other hand, while considering the value of the feature quantity recorded depending on the direction in the first coordinate system, the feature quantity in question is transformed into a second coordinate system in which the radiation center of gravity of the light radiation source is located at the origin of the coordinate system.

[0078] For the sake of simplicity, it should be noted that in the following description of the drawings, the terms "measurement quantity" and "feature quantity" are used synonymously. Here, the measurement quantity is the measured value measured by the sensor. The feature quantity may be the same as the measurement quantity or may be derived from the measurement quantity. For example, when the measurement quantity is illuminance, considering the fact that the luminous intensity of the light received by the sensor surface or the photometer of the sensor decreases when light is incident obliquely, and further considering the distance correction taking into account the distance between the radiation source and the sensor, the luminous intensity is calculated as the feature quantity of the radiation source from the illuminance.

[0079] The accurate determination of the position of the radiation center of gravity of the light radiation source with respect to the origin of the first coordinate system can be carried out, for example, by a tactile measurement system that extracts a specific mark on the vehicle and calculates the relative position therefrom. Such a tactile measurement system is manufactured and sold, for example, by Hexagon Metrology under the name "ROMER ABSOLUTE ARM". It should be further mentioned here that the radiation center of gravity of the headlamp attached to the vehicle is usually already indicated by the manufacturer by a mark attached in the closure plate of the headlamp and indicates the geometric center of gravity of the radiation beam emerging through the closure plate. For example, the accurate position of the radiation center of gravity with respect to the origin of the first coordinate system can be accurately recorded in this way.

[0080] The conversion of the feature quantities for a number of radiation directions to the corresponding values in the second coordinate system is performed by association or coordinate transformation. In this regard, an alternative embodiment will be described below with reference to FIGS. 2 to 5.

[0081] Record the recorded values of the first coordinate system, which is a cylindrical coordinate system. In the first step, convert the recorded values to another cylindrical coordinate system different from the cylindrical coordinate system in which the radiation center of gravity of the radiation source is at the origin. And in the second step, taking into account the distance, convert them to yet another spherical coordinate system. In this way, the above-mentioned coordinate transformation is performed. The radiation center of gravity of the radiation source is located at the origin of the coordinate system after conversion in the second step, and the spherical coordinate system after conversion in the second step is the desired second coordinate system.

[0082] Figures 2 and 5 show the above-mentioned procedure. Figure 2 shows a cylindrical coordinate system in which the origin moves on an arc. The locus of the cylindrical coordinate system moving with the origin is denoted by T. The locus D corresponds to the movement of the headlamp that is a problem of the vehicle 1 on the turntable 3. In this case, the turntable 3 or the headlamp is rotated by an angle D from the initial setting A1. In the display of Figure 2, the headlamp is rotated so as to be in the setting A2. Figure 2 shows the conventional parameters of the cylindrical coordinate system. The height S in this case indicates the position of the sensor 4 in the height direction according to Figure 1. In the cylindrical coordinate system, let the plane distance from the headlamp to the sensor 4 be p.

[0083] It should be noted that the cylindrical coordinate system of Figure 2 constitutes the aforementioned intermediate coordinate system. The measured values are first recorded in a first coordinate system that passes through the origin O and rotates around the rotation axis 31. The first coordinate system is also a cylindrical coordinate system.

[0084] The problem here is to convert the measured values in the first step into an intermediate coordinate system with parameters φ, p, and S (p and S are also measurable) based on the rotation angle D, and in the second step, from the parameters φ, p, and S, in the spherical coordinate system, calculate the parameter H indicating the azimuth angle and the parameter V indicating the elevation angle (defined as 90° minus the polar angle θ) according to the expression on the right side of Figure 5. Therefore, the determined spatial distribution of the characteristic quantity to be recorded is then recorded in relation to the spherical coordinate system in which the radiation center of the radiation source is located at the coordinate origin.

[0085] Therefore, before the local elevation angle V = 90° - θ of the object system of the headlamp is calculated from the height S and the local radius p, each rotation angle D has an accompanying local cylindrical coordinate system in which the local azimuth angle φ (H in the plane A, α system) is determined. Then, distance correction is performed according to the desired characteristic quantity, for example, luminous intensity.

[0086] Gonioradiometric calculations are performed, for example, by a calculation unit 6 schematically shown in FIG. 1, in order to calculate feature quantities for a number of radial directions in a second coordinate system. The calculation unit 6 records the rotation angle of the turntable 3 and the height S of the sensor 4, and has information about a predetermined distance in the measurement system. The measured values measured by the sensor 4 are also sent to the calculation unit 6. At the same time, the calculation unit can provide control commands, for example, to rotate the turntable 3 by a specific angle D or to move the sensor 4 to a specific height S.

[0087] The calculations will be described in detail below using FIGS. 3 and 4 as examples. FIG. 4 is an enlarged view of the left sub-region of FIG. 3.

[0088] [Arrangement for measurement] The arrangement for measurement in FIGS. 3 and 4 is 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 towards the screen, the positive Y-axis in the sense of positive rotation points upwards in the plane of the drawing (standardly, i.e., the light comes from the left), and the Z-axis points upwards outside the plane of the page. The headlamp 2 in the initial position A1 is located on a reference line F at a constant distance a from the center of rotation. However, their positions within the space of the headlamps 2 must be determined during the measurement operation in order to find the neutral position of the vehicle 1 from the measurement operation. The lateral distance of the headlamp from the center plane of the vehicle 1 is b, and the center plane of the vehicle 1 extends along the X-axis within the range of manufacturing tolerances and positioning accuracy.

[0089] The calculations are performed by applying a two-dimensional rotation matrix and analytic geometry in the said plane. As a basic consideration, a rotation of the point P(x, y) by D at R 2 is necessary. [Number] All the important points are rotated in the (x, y) plane from the neutral position, and the corresponding vectors suspended from the headlamp 2 as the radiation source are then calculated.

[0090] The measurement and the calculation of the feature quantity are subsequently carried out for both headlamps of the vehicle 1. That is, when one headlamp 2 is being measured, the other headlamp is turned off or covered, and vice versa. In an exemplary embodiment, consider the left headlamp 2.

[0091] [Calculation of H and p from D] First, from the rotation angle D, the azimuth angle φ (or H) and the local distance p in the local cylindrical coordinate system should be determined. Here, the local radius p is the distance between the headlamp 2 and the reference point of the position of the sensor 4 on the plane in question.

[0092] The arrangement is as follows. Angle of the turntable D As an example, 20.00° Distance from the reference line F to the center of rotation (= position of the headlamp) a Measured As an example, 2.750 m Distance from the reference line F to the screen d As an example, 25.000 m Distance from the center of rotation О to the screen r = d + a As an example, 27.750 m Position of the side headlamp b (Measured) Distance from the center of rotation О to the headlamp c c 2 = a 2 + b 2

[0093] The parameters of the operating headlamp are as follows. Coordinates of the operating headlamp with H = 0

Number

Number

Number

[0094] The parameters of the position of the photometer are as follows. Lateral distance of the photometer to the optical axis (x), determined from spatial geometry u XY-direction distance of the photometer from the center (y)

Number

Number

Number

[0095] The measurement distance is as follows. Vector

Number

Number

Number

Number

Number

[0096] Starting from such an arrangement and parameters, the azimuth angle φ (or H) and the local radius p in the local cylindrical coordinate system can be calculated as follows. During the rotation by D only,

Number

Number

Number

Number

Number

Number

Number

Number

Number

Number

Number

Number

Number

[0097] Conversely, D can also be determined from H by the same method. This is practically important, for example, when it is intended to approach a specific angle H.

[0098] In the next step, according to Figure 5 (right figure), the spherical coordinates H and V of the spherical coordinate system are determined. In this case, the azimuth angle H is the same as the azimuth angle in the local cylindrical coordinate system.

Number

Number

Number

Number

[0099] Finally, the radius R in the spherical coordinate system can also be calculated, for example, from V and S.

Number

[0100] Therefore, the spatial distribution of the characteristic quantity to be measured, for example, the luminous intensity, can be specified in a spherical coordinate system in which the radiation center of the radiation source is located at the center of the spherical coordinate system. Further, distance correction may be performed. Analyzing the equation in more detail, it can be seen that there is a bijective mapping within the defined or problematic angular range.

[0101] FIG. 6 shows another exemplary embodiment based on the exemplary embodiment of FIG. 1. In this case, a second mast 41 having a second sensor 4 is provided, and the second sensor 4 is also displaceable vertically along the mast 41 so as to be at different height positions. In this case, the second mast 41 is arranged closer to the turntable 3 than the first mast 40, for example, at a distance of 5 m, while the distance to the first mast is 25 m. Similar to FIG. 1, the configuration according to FIG. 6 includes a calculation unit, which is not shown separately.

[0102] Such an arrangement enables the goniometric measurement of a plurality of radiation sources simultaneously, and the sensors 4 arranged nearby are preferably used for measuring signal lights such as direction indicator lights on a vehicle. In the case of signal lights, since the far field already exists at a distance of 5 m, a larger apex angle can be measured at the same ceiling height.

[0103] FIG. 7 is a schematic exemplary embodiment in which the vehicle 1 arranged on the turntable 3 is rotated so as to be in at least two rotational positions for goniometric measurement, and the light reflected by the measurement wall 5 is recorded by a statically arranged camera 7.

[0104] In this case, the camera 7 is equipped with a two-dimensional sensor chip. In this case, the pixels of the sensor chip can be regarded as sensors in the context of the present invention. In this case, each pixel of the two-dimensional sensor chip is assigned to a wall element of the measurement wall 5. The sensor chip is, for example, a two-dimensional CCD sensor or a CMOS sensor. The camera 7 has an optical system that directs incident light onto the sensor chip.

[0105] The measurement wall 5 is configured to perform diffuse reflection, i.e., non-directional reflection, which uniformly diffuses the incident radiation in all directions. In particular, in order to minimize the influence on the spectrum of the reflection, the measurement wall 5 is gray or white. Therefore, the measurement wall 5 does not constitute a mirror that performs directional reflection satisfying the law of reflection.

[0106] The camera 7 is arranged and configured to record the light reflected by the measurement wall 5, and the reflected light is imaged on the sensor chip of the camera 7. The reflected light is recorded as a luminance distribution on the measurement wall 5 by the camera 7 for at least two settings of the turntable 3. The assigned calculation unit 6 (only schematically shown) is configured to convert the luminance distribution recorded by the camera 7 into a luminance distribution in a second coordinate system using coordinate transformation.

[0107] In this case, the calculation unit 6 performs goniometric calculations. The calculation unit 6 records the rotation angle D of the turntable 3 and the measurement data of the camera 7. At the same time, the calculation unit can provide, for example, control commands for rotating the turntable 3 by a specific angle.

[0108] The light source 2 generates a light distribution 9 on the measurement wall 5, and this light distribution 9 corresponds to the typical light distribution of an automobile headlamp in the illustrated exemplary embodiment. The light distribution 9 is recorded by the sensor chip of the camera 7 for each pivoting movement about the axis 31. The measurement wall 5 is located in the far field of the light distribution of the light source attached to the vehicle. For example, it is located 25 m from the headlamp or the light source.

[0109] Accordingly, in this exemplary embodiment, instead of the linearly moving photometer according to the exemplary embodiment of FIG. 1, a photometrically corrected camera measurement wall system is used, and the camera is distinguished in that it measures the reflected luminance of the luminance or illuminance by the lighting system of the vehicle on the measurement wall. All that is required in this case is the rotational movement of the vehicle and a wall measurement system by camera measurement that can record the entire angular range in a single luminance image.

[0110] The luminance distribution measured on the wall by the camera is then converted into the photometric distribution of the headlamp using coordinate transformation. In this case too, a combined coordinate system is used. That is, the conversion from the wall coordinates where the luminance camera confirms the measured value to the spherical coordinates in the reference system of the headlamp changes according to the rotation of the headlamp in space. If the coordinates of the headlamp are known as a function of the angle of the rotating device, it becomes possible again to find a bijective mapping that can calculate the light distribution in the reference system of the test object from the angle of the rotating device and the height of the headlamp. Then, most of the partial angular ranges can be combined to form the overall angular distribution.

[0111] The advantage of the above method is that by combining the rotation of the vehicle and the measurement of the camera, data can be acquired more quickly than the speed possible in the sequential grid measurement by the photometer.

[0112] However, the measurable width of the measurement by the indirect measurement by the camera 7 is small compared to the direct measurement by the photometer. This is related to the fact that when using the camera 7, the suppression of scattered light in both the measurement space and the objective lens is limited. Therefore, a brightness difference exceeding 100:1 can be achieved only at a high cost. Considering this, it may be possible to provide a facility for re-measuring the characteristic points of the light distribution using a firmly attached sensor 8 having a higher measurable width. Such a further sensor 8 is schematically shown in FIG. 7.

[0113] According to an alternative embodiment, for this purpose, an opening (not shown) is formed in the measurement wall 5, for example on the optical axis of the radiation source, through which the light emitted from the radiation source passes and which is detected by an additional sensor. In this case, the additional sensor is arranged either behind the measurement wall 5 or on-axis in the opening. Ideally, the sensor surface is part of the measurement wall and exhibits a similar reflection or scattering behavior with respect to the incident light. Alternatively, such a sensor 8 is arranged in front of or next to the measurement wall 5 while being arranged in a far field. It is also possible for such a sensor 8 to be movable and thus to be able to adopt a number of positions in front of the measurement wall 5.

[0114] With such a sensor 8, the entire range of the light distribution covered by the measurement wall can be accurately calibrated. Since the position of such an additional sensor 8 is known, for the angular determination of characteristic points of the light distribution, it is only necessary to use the combination of the measurement wall 5 and the camera 7. This is related to the advantage that the measured values are traceable because it is not necessary to calibrate the combination of the measurement wall 5 and the camera 7 absolutely and it can be calibrated during the measurement by a photometer.

[0115] As already mentioned, the camera 7 records the solid angle defined by the measurement wall 5 for each rotation setting of the turntable 3. By connecting the individual solid angles with different rotation settings of the turntable 3, the entire light distribution can be synthesized over a larger solid angle range in question, particularly in a coordinate system in which the radiation source or the headlamp is located at the origin of coordinates. The corresponding projection is shown in FIG. 8.

[0116] According to another alternative and exemplary embodiment, the turntable 3 in FIG. 1 can be further tilted around an axis perpendicular to the rotation axis 31, for example, around the Y axis. Therefore, the turntable 3 itself generates the movement of the radiation source during the measurement process around the first axis 31 and around a second axis perpendicular to the first axis 31. In this case, of course, not all spatial directions of the sphere can be recorded goniometrically. Only the forward-facing solid angle can be recorded goniometrically. However, this is sufficient for the application of measuring the illuminance of the headlamp. Alternatively, the vehicle on the turntable can also be tilted around the horizontal axis, for example, by raising the front or rear part, and as a result, the same effect as tilting the turntable is achieved.

[0117] In this configuration, for goniometric measurement, it is sufficient to use only a static sensor that acquires the measured value of the emitted radiation, which is the same as the feature quantity to be determined for each combination of the rotation angle and the tilt angle, or can derive the feature quantity to be obtained from the static sensor. The use of a static sensor is particularly advantageous when the ceiling height is limited. The tilt of the vehicle body corresponding to the tilt of the turntable may be immediately recorded by a separate measurement system.

[0118] Such an arrangement has the advantage that it is not necessary to move the photometer on the linear axis to adjust the height angle in the combined cylindrical coordinate system. Instead, it can be adjusted by tilting the vehicle forward or backward. However, the aforementioned disadvantages due to the tilt of the vehicle on the chassis need to be recorded and corrected. This is done, for example, by using cameras installed on the left and right sides of the vehicle, measuring the marked points on the vehicle body, and recording the actual tilt angle of the vehicle with respect to the horizontal neutral position without being affected by the chassis, such as the compression of the spring or the air pressure of the tires that may impair the vertical angle.

[0119] The measurement is performed, as in FIG. 1, by rotating the platform 3 on which the tilting vehicle 1 is placed so that the headlamp moves along an arc centered on the midpoint of the rotating device. Such measurements can be repeated for different tilting angles.

[0120] In this exemplary embodiment, the arrangement used for the measurement is described by a spherical coordinate system, and the origin of the spherical coordinate system moves on the sphere. This is because, due to the tilting of the vehicle 1 about two mutually perpendicular axes on the turntable, measurement values on the sphere corresponding to the internal spherical coordinate system of FIG. 9 that constitutes the first coordinate system can be obtained. The corresponding measurement values confirmed for various radial directions need to be converted to the coordinates of a second, external coordinate system in which the radiation center of gravity of the radiation source is at the coordinate origin. The conversion is performed by coordinate transformation between two coupled spherical coordinate systems, and the absolute value described by the first equation is further corrected by the law of distance and the angle of incidence with respect to the photometer.

[0121] According to the described invention, it becomes possible to objectively evaluate the lighting device of a vehicle in a mounted state in a laboratory in a metrological manner. The advantage compared to methods performed outdoors and / or during driving is that the influence of the road (reflection, dry or wet state) and the influence of residual luminance or the atmosphere can be eliminated. On the other hand, the described invention enables the light-emitting function, which has already been pre-assembled as a large component, to be arranged off-center on a goniometer and the measurement results to be converted to the reference system of the device under test by a bijective, i.e., uniquely reversible, association.

[0122] The method according to the invention using an off-center arranged radiation source (providing the light-emitting function to be evaluated) enables the recording of the characteristic quantity to be determined in a coordinate system in which the radiation center of gravity of the radiation source is located at the coordinate origin, even if the radiation source is arranged off-center.

[0123] One of the advantages of this method is that it is not necessary to change the position of the vehicle and move the radiation source to be tested to the coordinate origin of the goniometer. Thereby, while the advantage in space is obtained, on the other hand, it is guaranteed that the vehicle to be tested is placed at a predetermined location, or, when the rotary table is further combined with a rotary test tool, it is in a predetermined running state.

[0124] The above-mentioned conversion of the coordinate system using a radiation source arranged with its center shifted, in principle, even for a measurement arrangement in which a component having a radiation source arranged to shift the center within the component is goniometrically measured in another way without using the turntable shown in FIG. 1, it should be pointed out that it can be performed for any goniometric measurement. As the above-mentioned another method, for example, there is one using a robot to rotate the component around two axes orthogonal to each other.

[0125] It should be understood that the present invention is not limited to the above embodiments, and various changes and improvements are possible without departing from the gist of the present invention described above. It should be further pointed out that, unless mutually exclusive, any of the described features can be used individually or in combination with any other feature. The present disclosure extends to all combinations and sub-combinations of one or more of the features described herein and includes these. As long as a range is defined, all values within these ranges and all sub-ranges included within the ranges are included.

Claims

1. A method for measuring at least one illumination or radiation characteristic quantity of a light radiation source (2) attached to an object (1), which depends on direction, comprising: placing 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 the intersection of the surface (32) of the turntable (3) having the rotation axis (31) and the spatial axis of the first coordinate system that coincides with the rotation axis (31); placing the object (1) on the turntable (3) such that the radiation center of gravity of the light radiation source (2) is separated from the origin (O) of the first coordinate system; determining the position of the radiation center of gravity of the light radiation source (2) with respect to the origin (O) of the first coordinate system as a relative position; performing a gonioradiometric measurement including rotation of the object (1) about an axis, wherein the gonioradiometric measurement is performed in the first coordinate system, the object (1) on the turntable (3) is rotated from an initial position (A1) around the rotation axis (31) of the turntable (3), and the rotation axis (31) of the turntable (3) constitutes the vertical axis of the gonioradiometric measurement; recording the measured quantity of the radiation source depending on direction by the gonioradiometric measurement for a plurality of radiation directions, and assigning a measured value of the measured quantity to each radiation direction defined in the first coordinate system; calculating the measured quantity for a plurality of radiation directions in a second coordinate system in which the radiation center of gravity of the light radiation source (2) is at the origin of the coordinate system, from the measured values confirmed in the first coordinate system and recorded depending on direction, and the relative position; wherein the measured quantity is the same as the characteristic quantity to be measured, or the characteristic quantity to be measured is calculated from the measured quantity; A measurement method.

2. wherein the object (1) is an automobile or a part; the radiation source (2) is attached to the automobile or the part; and the automobile or the part is placed on the turntable (3) in such a way that the radiation center of gravity of the light radiation source (2) is separated from the origin (O) of the first coordinate system, the measurement method according to claim 1.

3. rotating the turntable (3) step by step the measurement method according to claim 1 or 2.

4. While recording the measured values at a predetermined angle, continuously rotate the turntable (3). The measuring method according to claim 1 or 2, characterized in that.

5. The geometric centroid of the radiation beam passing through the closing plate that separates the radiation source (2) from the surroundings is defined as the radiation centroid of the radiation source (2). The measuring method according to any one of claims 1 to 4, characterized in that.

6. The calculation of the measured quantity depending on the direction in the second coordinate system from the value of the measured quantity recorded depending on the direction in the first coordinate system is performed by associating the coordinates of the value recorded in the first coordinate system with the corresponding coordinates of the second coordinate system. The measuring method according to any one of claims 1 to 5, characterized in that.

7. In addition to the rotation of the object (1) on the turntable (3), The goniometric measurement includes recording the measured quantity as a function of the position (S) along the straight line using one or more sensors (4) along the straight line. The measuring method according to any one of claims 1 to 6, characterized in that.

8. A sensor (4) that moves along the straight line and acquires a measured value of the radiation emitted at a predetermined position (S) on the straight line is Used for the goniometric measurement. The measuring method according to claim 7, characterized in that.

9. Measure the illuminance as the measured quantity, The luminous intensity as the characteristic quantity to be measured of the radiation source (2) is calculated from the illuminance by the following formula 【Number 1】 Here,[[]] I is the luminous intensity,[[]] E is the measured illuminance,[[]] d is the distance between the light source and the sensor,[[]] (H, V) is the angle at which the sensor directed exactly parallel to the X-axis is irradiated, that is,[[]] H corresponds to the azimuth angle φ,[[]] V corresponds to the value obtained by subtracting the polar angle θ from 90° Calculate with The measuring method according to claim 7 or 8, characterized in that.

10. The first coordinate system is a cylindrical coordinate system,[[]] The coordinates of the value recorded in the first coordinate system are converted in the first step to another cylindrical coordinate system in which the radiation centroid of the radiation source (2) is at the origin of the coordinate system,[[]] The coordinates of the value recorded in the first coordinate system are converted in the second step to a spherical coordinate system in which the radiation centroid of the radiation source (2) is at the origin of the coordinate system,[[]] The spherical coordinate system is the second coordinate system. The measuring method according to any one of claims 7 to 9, characterized in that.

11. For each radiation direction, the azimuth angle (H) and elevation angle (V) of the position (P) of the sensor in the second coordinate system are calculated from the rotation angle (D) of the rotating plate (3) and the height (S) of the sensor (4) in the first coordinate system, the value of the measurement quantity in question measured by the sensor (4) is assigned to a specific radiation direction specified by the azimuth angle (H) and elevation angle (V), and is corrected by the incident distance and incident angle to the sensor (4) in order to obtain the characteristic quantity from the measurement quantity, The measurement method according to claim 10, characterized in that.

12. The rotation axis (31) of the turntable (3) extends in the vertical direction, The straight line (40) along which the measurement quantity is recorded also extends in the vertical direction. The measurement method according to any one of claims 7 to 11, characterized in that.

13. In addition to the rotation of the object (1) on the turntable (3) and the recording of the measurement quantity along the straight line (40) as a function of the position along the straight line (40), the goniometric measurement includes the recording of the measurement quantity along the second straight line (41) as a function of the position along the second straight line (41) when the first line (40) and the second line (41) extend in parallel and are arranged at different distances from the origin (O) of the first coordinate system, The measurement method according to any one of claims 7 to 12, characterized in that.

14. In addition to the rotation of the object (1) on the turntable (3), the goniometric measurement is characterized by including the recording of the measurement quantity by a statically arranged camera (7), where, the radiation emitted from the radiation source (2) is diffusely reflected by the reflection measurement wall (5) and is recorded by the camera (7) as the luminance distribution on the measurement wall at least in two settings of the turntable (3), the luminance distribution recorded by the camera (7) is converted into the luminance distribution in the second coordinate system by coordinate transformation, and the luminance distribution constitutes the measurement quantity, The measurement method according to any one of claims 1 to 6, characterized in that.

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

16. Additionally, an additional sensor (8) is directly irradiated, The method according to claim 14 or 15, characterized in that the signal recorded by the sensor (8) is used for the calibration of the camera (7).

17. In addition to the rotation of the object (1) on the turntable (3), the goniometric measurement includes an inclination around an axis perpendicular to the axis of rotation (31) of the turntable (3) or the object (1), the object (1) is rotated with respect to a number of inclination angles, and the measured quantity is recorded for each combination of rotation angle and inclination angle, the measured quantity is recorded based on a goniometric measurement (2) on the spherical surface around the radiation center of gravity of the radiation source, The measurement method according to any one of claims 1 to 6, characterized in that.

18. In the goniometric measurement, a static sensor for acquiring a measured value of the emitted radiation is used for each combination of rotation angle and inclination angle The measurement method according to claim 17, characterized in that.

19. The calculation of the measured quantity that depends on the direction in the second coordinate system from the value of the measured quantity recorded depending on the direction in the first coordinate system is performed by a correspondence that converts the coordinates of the value recorded in the first coordinate system into the corresponding coordinates in the second coordinate system, the second coordinate system is a spherical coordinate system, and the origin of the second coordinate system moves on the spherical surface, The measurement method according to claim 17 or 18, characterized in that.

20. A method for measuring at least one illumination or radiation feature quantity of a light radiation source (2) attached to an object (1) that depends on the direction, The object (1) is arranged on or on the surface of a holding element that is intended and configured to rotate the object (1) around a first axis and a second axis perpendicular to the first axis, the object (1) is arranged on the surface of the holding element such that the radiation center of gravity 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 gravity of the light radiation source (2) relative to the origin (O) of the first coordinate system as a relative position, performing a goniometric measurement including the rotation of the object (1) around the two axes in the first coordinate system The measured quantity of the radiation source (2) is recorded as being direction-dependent by means of goniometric measurements for a plurality of radial directions, and a measured value of the measured quantity is assigned to each of the radial directions defined in the first coordinate system. From the measured values of the measured quantity recorded as being direction-dependent and the relative positions, as ascertained in the first coordinate system, direction-dependent measured quantities are calculated for a plurality of radial directions in a second coordinate system in which the radiation center of gravity of the light radiation source (2) is at the coordinate origin. The measured quantity is the same as the characteristic quantity to be measured, or the characteristic quantity to be measured is calculated from the measured quantity. Measuring method.

21. A goniometer for measuring at least one illumination or radiation characteristic quantity of a light radiation source (2) attached to an object (1) as being direction-dependent, 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 of the turntable (3) having the rotation axis (31) and the spatial axis of the first coordinate system that coincides with the rotation axis (31), and the turntable (3) is intended to receive the object (1) such that the radiation center of gravity of the light radiation source (2) is remote from the origin (О) of the first coordinate system, at least one sensor (4) configured and intended to measure the measured quantity of the radiation source (2), wherein the turntable (3) and the at least one sensor are configured to perform a goniometric measurement including rotation of the object (1) about the rotation axis (31) of the turntable (3) in the first coordinate system, the measured quantity being recorded as being direction-dependent by means of goniometric measurements for a plurality of radial directions, and a measured value of the measured quantity being assigned to each of the radial directions defined in the first coordinate system, including a calculation unit (6) intended and configured to calculate the measured quantity for a plurality of radial directions in a second coordinate system in which the radiation center of gravity of the light radiation source (2) is located at the origin of the coordinate system, from the position of the radiation center of gravity of the light radiation source (2) relative to the origin of the first coordinate system and the values recorded as being direction-dependent of the measured quantity ascertained in the first coordinate system. The calculation unit (6) is further intended and configured to calculate the quantity to be measured from the measured quantity if the measured quantity is not a characteristic quantity to be measured yet. Goniometer. **Claim 22** The goniometer forms a type 3 goniometer, The at least one sensor records the measured quantity along the straight line as a function of the position (S) in the height direction along the straight line. The goniometer according to claim 21, characterized in that. **Claim 23** The goniometer, A reflection measurement wall (5) that performs diffuse reflection and reflects the light emitted from the radiation source (2); A camera (7) that is arranged statically and immovably and has a two-dimensional sensor chip in which pixels of the sensor chip form at least one sensor, where The camera (7) is arranged and configured to record the light reflected by the measurement wall (5) for at least two settings of the turntable (3), the reflected light is imaged on the sensor chip of the camera (7), and the reflected light is recorded by the camera (7) as a luminance distribution on the measurement wall (5). The calculation unit (6) is configured to convert the luminance distribution recorded by the camera (7) into a luminance distribution in the second coordinate system by coordinate transformation. The goniometer according to claim 21, characterized in that. **Claim 24** The at least one sensor includes a static sensor, The turntable (3) is configured to tilt the object (1) arranged on the turntable (3) around an axis perpendicular to the rotation axis (31) in addition to rotation around the rotation axis (31), or the object (1) is arranged to be tiltable around an axis perpendicular to the rotation axis (31). The turntable (3) or the object (1), and the at least one sensor cooperate during the goniometric measurement such that the object (1) is rotated during the goniometric measurement for a number of tilt angles, and the static sensor records the measured quantity for each combination of rotation angle and tilt angle. The goniometer according to claim 21, characterized in that.

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