Method for displaying a light animation on the lighting system of a motor vehicle

Abstract

The invention relates to a method for displaying a light animation on a light system (1) implemented by a graphics engine (MG1, MG2, MG3) equipped with a description library (D2i,j) of light sub-animations, comprising the following steps: (E1) providing the graphics engine with a description (D1) of at least one element (21, 22, 12) of the light system; (E0) receiving a display command (Zi) of a light animation (Ai) on the element; (E2) retrieving, upon receipt of said command, a set of descriptions (D2i,j) of light sub-animations realizing said light animation; (E3, E4, E5, E6, E7) determining by the graphics engine a sequence of control instructions (bk) of said element from the description of each light sub-animation of said element; (E9) control of the element by means of the control instruction sequence to display said light animation. Figure to be published with the abbreviation: Fig. 1

Description

Title of the invention: Method for displaying a light animation on a lighting system of a motor vehicle

[0001] Technical field,

[0002] The invention relates to the technical field of automotive lighting and / or automotive signaling. More particularly, the invention relates to the field of displaying a light animation on a lighting system of a motor vehicle.

[0003] State of the art,

[0004] In the field of lighting the interior of motor vehicles or of signaling of motor vehicles, lighting systems now comprise sufficient light sources to enable light animations to be displayed thereon. It is thus, for example, known to display on a rear light of a motor vehicle a light animation consisting of a movement of an arrow making it possible to indicate to a road user a direction that the vehicle will take or to display on a light strip inside a vehicle a scrolling light signal making it possible to indicate to the driver the direction of a danger on the road.

[0005] In this type of system, each light animation is determined beforehand as a function of the number and position of each of the light sources of the lighting system; the light animation is stored in a memory of the lighting system in the form of a sequence of control instructions for each of these sources. When a light animation is launched, a control system is responsible for determining a sequence of control instructions for the light sources making it possible to display the light animation on the lighting system of the motor vehicle.

[0006] In other words, this type of system is particularly rigid and does not allow animations to be generated dynamically. In addition, for any new animation that one wishes to generate, it is necessary to calculate beforehand, on a computer, an entire sequence of control instructions, then to store it in the memory of the device in order to test and verify it, and to modify it if necessary until arriving at a sequence of instructions considered satisfactory. It is therefore not possible to test, generate and update animations simply and quickly. Finally, each animation is particularly dependent on the structure of the lighting system, and in particular on the technologies used and the spatial distribution of the light sources. Any evolution of the design of a lighting system therefore involves recalculating the animations and it is not easy to reuse a previously generated animation for a lighting system.

[0007] In this context, application FR3096435 has devised a method in which a simple description of a light animation is provided to a graphics engine, which then determines, for a given structure of a light system, a rendering of this light animation and in which a control of the light system can then control the sources of the light system from this rendering.

[0008] Since the graphics engine can be embedded in a vehicle computer and in a computer equipped with a vehicle simulation environment, it is thus possible to implement a light animation in a virtual representation of the light device without having to physically implement it in the light device itself. Therefore, the animation can be tested and validated easily and simply, regardless of the design of the light device for which it is intended. Subsequently, only the description of the animation must be provided to the embedded graphics engine so that it can generate a rendering for the design of the vehicle's light device. Therefore, this description can be used for different designs and can be easily updated.

[0009] While this solution does indeed meet the various needs mentioned above, it has a major drawback. Indeed, in the case of displaying a complex animation requiring several objects or in the case of displaying several simultaneous animations, the size of the RAM and / or buffer memory required by the graphics engine can be particularly large. Indeed, in the automotive sector, it is not possible to dynamically allocate memory space to a computer. Exceeding this memory space could compromise essential or vital functions of the vehicle, and would therefore lead to a major risk for the safety of the vehicle's occupants. In this context, it is therefore necessary to size the size of the memory accessible by the graphics engine with respect to the most complex cases, which therefore generates problems of space and cost.

[0010] There is thus a need for a method for displaying a light animation on a lighting system of a motor vehicle, which makes it possible to easily and simply test, validate and update a light animation regardless of the design of the lighting system for which it is intended and which does not require significant dimensioning of a RAM and / or a buffer memory for calculating the control instructions of the lighting system.

[0011] The invention therefore falls within this context and seeks to resolve all of the aforementioned drawbacks.

[0012] Presentation of the invention.

[0013] The invention thus relates to a method for displaying a light animation on a lighting system of a motor vehicle comprising a controller and a plurality of light sources selectively controllable by the controller, the method being implemented by a graphics engine equipped with a memory in which a library for describing light sub-animations is stored, comprising the following steps: a. step of providing the graphics engine with a description of at least one element of the lighting system defining the number and position of the light sources of this element; b. step of receiving by the graphics engine a command to display a first light animation on the element of the light system; c. step of recovery by the graphics engine, upon receipt of said display command, of a first set of descriptions of light sub-animations stored in said memory and making it possible to produce said first light animation together; d. step of determining by the graphics engine a sequence of instructions for controlling the light sources of said element to display said first light animation, the sequence of control instructions being determined from the description of each light sub-animation of the first set, and as a function of the description of said element; e. step of controlling by said controller, the light sources of the element of the lighting system by means of the sequence of control instructions to display said first light animation on the lighting system.

[0014] In the invention, the step of providing a description of an element of the lighting system to the graphics engine makes it possible to know the exact location of the available light sources, in particular their spatial distribution, and to associate with each of them an identifier, in particular a digital index making it possible to individually control said light source.

[0015] It is further understood that the graphics engine is equipped with a library of light sub-animations that can be combined with each other to form a large number of complex light animations. The graphics engine can thus receive a display command specifying one or more light sub-animations to be produced in order to display a light animation on an element of the light system.

[0016] Thus, following the reception of this command to display a first light animation, the graphics engine can thus recover a first set of one or more descriptions of light sub-animations making it possible to generate this first light animation. This decomposition thus makes it possible to limit the working memory space of the graphics engine. In addition, the step of determining the instruction sequence by the graphics engine is thus limited to the rendering of these light sub-animations, and therefore of the first light animation, for the available light sources, and not to all of these sub-animations. The graphics engine can then transmit said sequence of instructions to the controller to individually control each of the light sources and to assign to it the photometric characteristics necessary to correctly render said light animation. It is therefore understood that the advantages of the solution of the previous application FR3096435 are thus preserved, each light sub-animation being able to be tested, validated and updated easily, without depending on the design or the technology choice of a lighting system, and that the invention also makes it possible to avoid excessive dimensioning of the RAM and / or the buffer memory of the graphics engine.

[0017] In an alternative or cumulative embodiment of the invention, the lighting system may be a virtual lighting system, in particular generated via a computer simulation environment of a motor vehicle and in particular of a passenger compartment of a motor vehicle. Advantageously, the method for displaying a lighting animation makes it possible to simulate the final rendering of a lighting animation on such a virtual lighting system so that the result can be tested and validated prior to its deployment on the real lighting system of a motor vehicle.

[0018] In an alternative or cumulative embodiment of the invention, the lighting system may be a lighting system of a motor vehicle, and in particular a lighting system arranged inside a passenger compartment of a motor vehicle and / or outside a motor vehicle.

[0019] Definitions

[0020] In the present invention, the term "graphics engine" means one or more electronic components capable of manipulating digital data, in particular an electronic control unit, a central processing unit or a processor which can be embedded in a desktop or laptop computer, a digital tablet or even in a motor vehicle, and capable of communicating with memory storage systems and / or electronic systems, in particular via cables or a wireless link, such as headlights of a motor vehicle.

[0021] In the case where the graphics engine is embedded in a motor vehicle, it is possible to provide either a single graphics engine for the entire lighting system or a plurality of graphics engines, each associated with a group of light sources of the lighting system and thus implementing the steps of the method for this group of light sources. Where appropriate, the lighting system may comprise a central controller capable of controlling each of these graphics engines.

[0022] In the present invention, the term "light source" means any light source, possibly associated with an electro-optical element, capable of being activated, deactivated and / or selectively controlled to emit an elementary light beam whose light intensity is controllable. It may in particular be a light-emitting semiconductor chip, a light-emitting element of a monolithic pixelated light-emitting diode, a portion of a light converter element excitable by a light source or a light source associated with a liquid crystal or a micro-mirror.

[0023] In the present invention, the term "display of a light animation on a light system" means an evolution of the state of at least one light source of this light device over a given time range. Said state may in particular be characterized by a set of photometric characteristics of the light emitted by said at least one light source, in particular the color, the emission intensity, the emission frequency or even the polarization of said emitted light.

[0024] The display of a light animation may for example comprise a modification of the color and / or the intensity of the light emitted by all or part of the light sources of the light system and / or the emission of light, momentary and / or repeated, by all or part of the light sources of the light system to materialize the display and possibly the transformation of one or more objects, for example of their shape, their position, their color and / or their opacity, on all or part of the light system and / or to cause a change in a light ambiance, for example of its color and / or its intensity, generated by the light system.According to the invention, a light animation may be displayed only on a part of the light sources of the light system or on all of them and / or separate light animations may be displayed on the same set of light sources or on different parts of the light sources of the light system.

[0025] In the present invention, the term "element of the lighting system" means a predetermined set of light sources. Said element of the lighting system may in particular be a flat and / or curved screen or a strip of light sources or an external signaling device, of any shape and dimensions. The light sources of said element may be distributed in a one-dimensional manner, in particular aligned along a line, a curve and / or an arc parameterized in space; or in a two-dimensional manner or even in a three-dimensional manner.

[0026] For example, an element of the lighting system may refer to the entire set of light sources of the lighting system or only to a sub-part of said light sources. For example, two distinct elements of the system light sources may include one or more common light sources.

[0027] In the present invention, the term “sequence of instructions for controlling light sources of an element” means a temporal sequence of control instructions, each control instruction comprising a set of information, in particular in the form of a sequence of bits, comprising for each light source of said element at least one elementary instruction from: a. a light intensity instruction of the light source, b. a light source color instruction or gray level, in particular in the form of a color code such as RGB (Red, Green, Blue) or HSV (Hue, Saturation, Value); c. a time range for switching on the light source.

[0028] If desired, each of said information may be associated with an identifier of the light source for which it is intended, such as a set of spatial coordinates and / or an index of a pixel. Alternatively, said information may be stored in a table whose ordering of the boxes corresponds to the spatial arrangement of the light sources of said element.

[0029] Embodiments

[0030] In one embodiment of the invention, the description of said element comprises a description of a model of said element comprising a spatial distribution of light sources of said element and a description of an arrangement of said model in a spatial reference frame.

[0031] Advantageously, the spatial reference system makes it possible to locate, by means of coordinates, the location of each light source of said element by matching said coordinates of a point of the model to those of the corresponding light source. Said spatial reference system may in particular be a two-dimensional or three-dimensional reference system, not necessarily Euclidean, and may in particular use curvilinear coordinates to locate a point on a curved surface or along a one-dimensional curve in space.

[0032] It is understood that the description of the model makes it possible to describe the distribution of the light sources independently of a spatial reference frame, so that the same description of a model can be used in the case where two elements of the lighting system are structurally identical but are positioned at different locations in the motor vehicle, which makes it possible to further limit the memory space required for the rendering carried out by the graphics engine. This is particularly the case if the dashboard of the motor vehicle has two identical right and left screens or if the passenger compartment of the vehicle has two light strips arranged symmetrically on the doors.

[0033] For example, in the case of a one-dimensional distribution, such as a band, a spatial distribution of light sources of said element may comprise only a number of light sources and a pitch separating two adjacent light sources. Alternatively, in the case of a two-dimensional distribution, such as a screen, a spatial distribution of light sources of said element may comprise only a number of light sources per column and per row and a vertical and / or horizontal pitch separating two adjacent light sources of the same column and / or the same row. As a further variant, a spatial distribution of light sources of said element may comprise, may comprise, for each light source, its position relative to an original light source.

[0034] Preferably, the arrangement of the model may include information making it possible to describe the position of the element in the spatial reference frame and possibly information making it possible to describe an enlargement or reduction factor of the model and / or an angle of rotation of said model.

[0035] Advantageously, a library of model descriptions and layout descriptions is stored in the memory and accessible by the graphics engine from said memory. Where appropriate, the graphics engine selects in advance from said memory the model and layout descriptions making it possible to describe the different elements of the lighting system from identifiers of these descriptions stored in said memory. Alternatively, the identifiers of said descriptions may be selected in advance and manually by a user.

[0036] Advantageously, each description of a light sub-animation stored in said memory of the graphics engine is independent of the number of light sources of the element of the light system and of the position of these light sources.

[0037] Advantageously still, each description of a light sub-animation may comprise at least one object and a transformation of said object during a period of time of said object. Preferably, the description of each sub-animation may comprise a description of an object comprising at least its shape and its position in a spatial reference frame, in particular the same spatial reference frame as that of the description of said element, and a description of a transformation of at least one characteristic of said object comprising at least start and end values ​​of said characteristic and a duration of said transformation. For example, the objects are described by a set of geometric shapes, for example straight line segments or polygons, defined by their vertices.Each control instruction can thus be determined by evaluating a view, also called a "frame" in English, of the sub-animation, that is to say of the object at a given instant of the transformation it undergoes. This view being a vector representation of the sub-animation, it is not limited to a given resolution, unlike a matrix representation, so . that it is therefore independent of the structure and the choice of technology of the element of the lighting system. Each successive evaluation of a view of the sub-animation, as the transformation undergone by the object evolves from its starting value to its end value and during the said duration of the transformation, thus makes it possible to obtain a new instruction for controlling the light sources of the lighting element and thus to sequentially display the sub-animation on this lighting element.

[0038] If desired, it may be provided that each description of a sub-animation includes a single description of an object and at least one description of a transformation of a characteristic of said object.

[0039] In the case where said first set comprises at least two descriptions of light sub-animations to be displayed, simultaneously and / or sequentially, on the element of the light system to form the first light animation, it may be provided that each description is associated with at least one priority index and / or at least one opacity coefficient. Where appropriate, the sequence of control instructions may be determined by the graphics engine from the description, the priority index and / or the opacity coefficient of each light sub-animation, and as a function of the description of said element. Indeed, it is for example possible to combine these sub-animations to give a superposition effect to the first animation. For example, the value of the priority index makes it possible to establish an order in which the different objects of the same animation must be displayed, in particular to produce visual effects of variable depth.Each higher-order sub-animation is thus assigned at least one opacity coefficient to determine whether lower-order sub-animations can show through this higher-order sub-animation.

[0040] In one embodiment of the invention, all of the descriptions of the light sub-animations are stored in said memory of the graphics engine in the form of a data tree, said data tree comprising a first sub-tree encoding a plurality of descriptions of objects each comprising one or more characteristics of said object, and a second sub-tree encoding a plurality of descriptions of a transformation of at least one characteristic of an object. Where appropriate, the step of retrieval by the graphics engine of said first set comprises the retrieval, for each sub-animation of the first set, of a description of an object in the first sub-tree and of a description of a transformation of at least one characteristic of said object in the second sub-tree.

[0041] In other words, the data tree structure makes it possible to describe in a simple, exhaustive and compact manner all of the information necessary for the construction of the set of descriptions of light sub-animations. in doing so, each sub-animation is described in full using the object(s) constituting said sub-animation and their respective graphic characteristics, in particular the size and color of said objects, and all of the transformations applying to at least one of the graphic characteristics of one of said objects.

[0042] If desired, the step of recovering the descriptions of an object and a transformation may be preceded by a step of decompressing the data tree.

[0043] In one embodiment of the invention, for each description of an object stored in said first sub-tree, said description comprises a value of at least one characteristic of the object chosen from at least the following characteristics: a. number of vertices of said object; b. position of the vertices of said object.

[0044] It may possibly be envisaged that said description also includes at least one property-type characteristic, the value of which can be fixed or modified using a sub-animation, chosen from the following characteristics: a. overall color of the object; b. color of each of the vertices of the object; c. overall opacity coefficient of the object; d. opacity coefficient of each of the vertices of the object; e. priority index.

[0045] In one embodiment of the invention, for each description of a transformation of at least one characteristic of an object stored in said second sub-tree, said description comprises at least a starting value of said characteristic, an end value of said characteristic, a duration of said transformation and a transition profile of said characteristic from its starting value to its end value. Said transformation may thus indifferently be a transition of the type moving the object to another position, rotation, change of color, change of opacity, modification of the number and / or position of one or more, or even all of the vertices, or even a combination of one or more of these transitions. Where appropriate, the transition profile may be a continuous or discontinuous function, such as for example a linear or quadratic or inverse or even identity function.

[0046] It will be noted that one can thus associate with the set of vertices a global, or unique, color of the object or associate with each vertex a color, the set of colors then forming a color map of the object allowing, by interpolation, to define color variations of the object. In a manner equivalent to the color, one can associate with the set of vertices a global, or unique, opacity coefficient, of the object or associate an opacity coefficient with each vertex, the set of coefficients then forming an opacity map of the object allowing, by interpolation, to define variations in opacity of the object.

[0047] By proceeding in this way, it is possible to specify for a given object the temporal and spatial evolution of at least one characteristic; the data tree thus contains all the information necessary for the execution of a light animation including in the case where several objects are present.

[0048] In one embodiment of the invention, the descriptions of the sub-animations stored in the memory are defined in the same spatial reference frame; each instruction of said sequence of control instructions is determined sequentially from the reception of said command, for each instruction of said sequence of instructions and for each light source of the element of the light system, the graphics engine determines: a. from said description of said element, the position of said light source in said spatial reference frame; b. for each light sub-animation of the first set, a value of said light sub-animation at said determined position and at a given time; c. a value of the first light animation at said position determined from the determined value of each light sub-animation of the first set; said instruction being determined from said determined value of the first light animation.

[0049] In other words, to calculate an instruction, the graphics engine samples a view at a given time of each sub-animation with respect to the position of the light sources in the spatial reference frame, it being understood that only the values ​​of the pixels of each sub-animation corresponding to the positions of the sources are determined. These values ​​may be grayscale values ​​or color values. The views being determined in the same spatial reference frame, and in particular the same spatial reference frame as that of the description of said element, the graphics engine can then perform a coherent superposition of the sub-animations in order to determine the final rendering of the animation to be displayed on the element of the light system, and therefore to determine an instruction.These different steps are thus renewed periodically, each sub-animation being re-evaluated and sampled at a later time to obtain a new instruction in the sequence of instructions until reaching the end of the light animation. It can be conceived that the graphics engine determines each value of each light sub-animation through the same thread executed by a processor, or through several parallel threads, for example. executed by a multi-core processor. Where appropriate, for each light source in the light system element, the graphics engine may, for example, determine all the values ​​of the light sub-animations at the determined position of this light source in the same thread of execution associated with this light source, or in a thread of execution associated with a set of light sources including this light source.

[0050] It will be noted that in the case where two sub-animations overlap at the same pixel, the graphics engine can advantageously use the priority indices of the sub-animations and the opacity coefficients to determine the rendering of the animation at this pixel. For example, said value of the light animation can be determined from the determined value of each light sub-animation and weighted using the priority index and / or the opacity coefficient of this light sub-animation.

[0051] It should be noted that the instruction can be formed by the set of values ​​of the light animation determined for each of the light sources of the element of the light system, each value then forming an elementary instruction of a light source. Alternatively, these values ​​can be transformed by the graphics engine, for example by means of gamma correction type operations, in order to obtain elementary instructions of the light sources.

[0052] In one embodiment of the invention, cumulative or alternative, the method comprises: a. subsequent to receiving the command to display the first light animation, receiving by the graphics engine a command to display a second light animation; b. upon receipt of said command to display the second light animation; the recovery by the graphics engine from said memory of a second set of descriptions of light sub-animations making it possible to produce said second light animation together; c. determining by the graphics engine a sequence of instructions for controlling the light sources of said element to display said first light animation and said second light animation, the sequence of control instructions being determined from the description of each light sub-animation of the first set, from the description of each light sub-animation of the second set, and according to the description of said element.

[0053] By doing so, the graphics engine is capable of generating consistent light source control instructions for any number of animations, including for two light animations that are offset in time and / or have different distinct execution times, due to the reception of distinct display commands. Indeed, it may be necessary to start, at any time, the display of a second light animation simultaneously with the first light animation currently being displayed. Such a situation arises, for example, during the sudden appearance of a road hazard or a technical fault. In this case, it may be necessary to display a light animation informing an occupant of the vehicle of the hazard and / or the technical fault. This light animation may then be superimposed on a first light animation currently being executed, in particular by being displayed with priority over said first animation. It should be noted that in this case, the graphics engine renders the light animations in the same spatial reference frame but in separate time frames specific to each light animation.

[0054] Similar to sub-animations, it is possible to combine light animations with a superposition or depth effect, by associating each animation with a priority index and a depth coefficient.

[0055] In one embodiment of the invention, for each instruction of said sequence of instructions and for each light source of the element of the light system, the graphics engine determines: a. from said description of said element, the position of said light source in said spatial reference frame, b. for each light sub-animation of the first set and of the second set, a value of said light sub-animation at said determined position; c. a value of the first light animation at said position determined from the determined value of each light sub-animation of the first set and a value of the second light animation at said position determined from the determined value of each light sub-animation of the second set; said instruction being determined from said determined values ​​of the first and second light animations.

[0056] In one embodiment of the invention, for each instruction of said sequence of instructions, the graphics engine increments a progress time of each light sub-animation of the first and second sets of sub-animations, the step of determining the value of each light sub-animation of the first and second sub-sets at said determined position being carried out according to said progress time of this sub-animation.

[0057] Preferably, the advancement time of a set of sub-animations, or of each sub-animation of a set of sub-animations is initialized following the receiving the command to display the light animation corresponding to this set. Following the incrementation of the progress time, for each instruction, the graphics engine then proceeds to sample a view at said progress time of each sub-animation, determines a rendering of each animation from the samplings of the sub-animations of the corresponding set, then composes into a global rendering from these renderings. These steps of incrementation, sampling and calculation of renderings are thus renewed periodically to generate new instructions until the progress time of a sub-animation exceeds the duration of the transformation(s) of this sub-animation. Once this duration is exceeded, this sub-animation is then no longer taken into account in the calculation of renderings by the graphics engine.

[0058] It should be noted that according to this characteristic, the temporal evolution of the sub-animations of each light animation is processed independently of the other light animations. Therefore, the speed of each sub-animation can be controlled independently of the other sub-animations. If desired, the advancement time of each light sub-animation may be different for each of said sub-animations, in particular be a multiple, integer or not, of a unit of time, in particular 1 ms.

[0059] In one embodiment of the invention, the method comprises a step of providing the graphics engine with an image or a sequence of images intended to be displayed simultaneously on the lighting system with said lighting animation, said image or sequence of images being associated with at least one priority index and / or at least one opacity coefficient; and the sequence of instructions for controlling the light sources of said element to display said lighting animation is determined by the graphics engine from the description, the priority index and / or the opacity coefficient of each lighting sub-animation, and from said image or sequence of images, its priority index and / or its opacity coefficient. It is thus possible, in addition to the dynamic display of lighting animations on the lighting system, to simultaneously display images, for example stored in the memory of the graphics engine or in another memory of the motor vehicle.

[0060] It may advantageously be provided that the plurality of light sources forms at least two groups of light sources each defining an element of the light system, the light sources being selectively controllable by a controller; and that the light system comprises a plurality of graphics engines each associated with an element of the light system and a master controller capable of controlling each of the graphics engines; the master controller and the graphics engines each comprising a clock.

[0061] Where appropriate, the method then comprises the following steps: a. step of providing each graphics engine with a description of the element of the associated lighting system, defining the number and position of the light sources of this element; b. step of providing each graphics engine with a description of at least one light sub-animation to be displayed on the element of the associated light system, all of the sub-animations forming a light animation; c. step of supplying, by the master controller, a clock signal generated by its clock, to each of the graphics engines; d. step of calculating, by each graphics engine, a time offset between a clock signal generated by its clock and the clock signal provided by the master controller; e. step of determining, by each graphics engine, a sequence of instructions for controlling the light sources of the element of the associated lighting system, each instruction being determined from the description of said associated element, the description of the light sub-animation provided to this graphics engine and a progress time of said light sub-animation determined from said time offset; f. step of controlling, by the controller, the light sources of each element of the lighting system by means of the sequence of control instructions determined by the associated graphics engine to display said light sub-animation on this element

[0062] It is thus understood that each graphics engine implements the same steps of the method according to the invention, as described previously, the instructions being determined according to its own clock frequency, each instruction being for example generated for each period, or multiple of periods, of clock. However, it is possible that the clock frequency differs significantly from one graphics engine to another, under the influence of an external parameter such as the temperature or even manufacturing tolerances of the graphics engines. These offsets then lead to a desynchronization of the sequences of instructions generated by the graphics engines, so that an unpleasant effect can be visible when displaying a light animation on several elements of the same light system.The above-mentioned characteristics thus allow each microcontroller to estimate the time offset of its clock with respect to the same reference clock signal, then to generate instructions which compensate for this estimated offset.

[0063] Advantageously, each graphics engine, for each instruction of said sequence of instructions and for each light source of the element of the associated light system: a. increments the progress time of the description of the light sub-animation provided to this graphics engine using a time step determined from said time offset; b. determines, from said description of said associated element, the position of said light source in said spatial reference frame; c. determines a value of said light sub-animation at said determined position and at said advancement time of this sub-animation, said instruction being determined from said determined value of this light sub-animation

[0064] Preferably, the steps of incrementing the advancement time, determining the position of the light source and determining the value of the light sub-animation are repeated until the advancement time exceeds the duration of the transformation of said sub-animation. In other words, the graphics engine can thus adapt the number of views of a sub-animation that it evaluates to proceed with a rendering of this sub-animation, with regard to the duration specified in the description of this sub-animation. However, each evaluated view can give rise to a new control instruction, so that the number of evaluated views directly impacts the actual display duration of the sub-animation on the element of the light system. It is thus possible to modulate the display duration of each sub-animation so that the sub-animations are displayed synchronously.

[0065] Advantageously, the graphics engine increases the time step if the period of the clock signal generated by its clock is greater than the period of the clock signal provided by the master controller and decreases the time step if the period of the clock signal generated by its clock is less than the period of the clock signal provided by the master controller. In other words, the time step is increased if the clock of the graphics engine is slower than that of the master controller and it is decreased if the clock of the graphics engine is faster than that of the master controller.

[0066] For example, the graphics engine may modify the time step using a factor determined from the ratio between the period of the clock signal provided by the controller and the period of the clock signal generated by its clock.

[0067] In one embodiment of the invention, the step of determining by the graphics engine a sequence of instructions for controlling the light sources of said element to display said first light animation comprises the generation of a sequence of control instructions each associated with one of the light sources of said element, the ordering of said sequence of instructions corresponding to the arrangement of the light sources of said element with respect to the motor vehicle.

[0068] Therefore, said sequence of instructions for controlling the light sources defines unambiguously sequences of instructions for each of the light sources according to its position in the spatial reference. Thus, the image constructed by all the light sources makes it possible to generate a global image consistent with the light animation resulting from the different light animation display commands received by said graphics engine.

[0069] Preferably, when the controller of the lighting system receives a control instruction determined by the graphics engine, it successively controls the light sources of the element of the lighting system according to this control instruction. For example, for each control instruction, in the case where each light source of the element of the lighting system comprises three light-emitting chips of red, green and blue color respectively, the controller will be able to generate for each selected light source, three PWM (Pulse Width Modulation) modulated signals whose duty cycles are determined according to the instruction contained in the control instruction associated with this light source and provides these signals to said light source.

[0070] The invention also relates to a computer program comprising a program code which is designed to implement the method according to the invention.

[0071] The invention also relates to a data medium on which the computer program according to the invention is recorded.

[0072] Brief description of the figures,

[0073] The present invention is now described using examples which are solely illustrative and in no way limitative of the scope of the invention, and from the attached illustrations, in which:

[0074] [Fig-1] represents, schematically and partially, a luminous system of a motor vehicle for implementing a method according to one embodiment of the invention;

[0075] [Fig.2] represents, schematically and partially, a method of displaying a light animation on the light system of [Fig.l] according to one embodiment of the invention;

[0076] [Fig.3] represents, schematically and partially, a data tree in which a plurality of descriptions of light sub-animations are stored for the implementation of the method of [Fig.2];

[0077] [Fig.4] represents, schematically and partially, an example of implementation of the method of [Fig.2] for displaying a light animation on the light system of [Fig.l];

[0078] [Fig.5] represents, schematically and partially, a time graph describing a sequence of light animations displayed on the light system of [Fig.l] using the method of [Fig.2];

[0079] [Fig.6] represents, schematically and partially, a time graph representing a sequence of light animations displayed on the light system of [Fig.l]; and

[0080] [Fig.7] represents, schematically and partially, a time graph re showing a sequence of light animations displayed on the light system of [Fig.l] using the method of [Fig.2].

[0081] In the following description, elements that are identical, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0082] Description of the embodiments,

[0083] [Fig.l] shows a lighting system 1 of a motor vehicle for implementing a method of displaying one or more light animations according to an embodiment of the invention.

[0084] In the example described, the lighting system 1 is a system for lighting the passenger compartment of the motor vehicle, comprising a central strip 21 of light sources arranged at a dashboard of the vehicle as well as a right strip 22 and a left strip 23 of light sources arranged symmetrically at the right and left doors of the vehicle. Each of the strips 21, 22 and 23 comprises a matrix of light sources of the light-emitting diode type, distributed in rows and columns. Furthermore, the strips 22 and 23 are symmetrically identical. Each of the strips thus forms an element of the lighting system 1.

[0085] This example is given as a non-limiting example, and other types of lighting systems may be designed without departing from the scope of the present invention. In particular, the number of elements of the lighting system, their arrangement with respect to the motor vehicle, whether interior or exterior, the number of light sources of each element, their spatial distribution, their dimensions, the type of light that they are capable of emitting as well as the technology of these light sources may be varied without departing from the scope of the present invention. Each element may indifferently be a device of an interior lighting system of the motor vehicle, a road lighting device or a signaling device of the motor vehicle.

[0086] Each element 21 to 23 of the lighting system 1 is associated with a graphics engine MGi to MG3, intended to generate instructions for controlling the light sources of this element, and a controller Pi to P3, intended to control the light sources of this element from the instructions generated by the associated graphics engine.

[0087] Each graphics engine includes a memory (not shown), in which a library of descriptions of light sub-animations and a library of descriptions of light system elements are stored.

[0088] The lighting system 1 also comprises a master controller BCM capable of controlling each of the graphics engines and transmitting data frames to them via an on-board data communication network.

[0089] [Fig.2] shows a method of displaying a light animation on the system 1 according to an embodiment of the invention.

[0090] It should be noted that the lighting system 1 may be a real lighting system of a motor vehicle or a virtual lighting system, simulated through a simulation environment of the motor vehicle, in order to test and validate lighting animations before deploying them on a real vehicle. The description of the method which follows can thus be applied indifferently to a real lighting system or to a simulated lighting system.

[0091] For the sake of brevity, the method will be described with respect to the graphics engine MGi, the controller Pi and the element 21 only, it being understood that the same method is implemented by the other graphics engines, controllers and elements.

[0092] In a step E0, the graphics engine MGi receives a command Zi to display a light animation A; on the element 21.

[0093] In a step El, the graphics engine MGi retrieves, in its memory, a description DI of the element 21 and in a step E2, the graphics engine MGi retrieves, in its memory, a set of descriptions D2ij of light sub-animations making it possible to carry out together the light animation A;.

[0094] The descriptions DI of element 21 and D2LJ of each light sub-animation may for example be retrieved using identifiers of element 21 and the sub-animations contained in the command Zj. According to the command Zi5 the set of sub-animation descriptions may include one or more descriptions D2;j.

[0095] The library of element descriptions may, for example, include a sub-library of element model descriptions, i.e., different spatial distributions of light sources independent of any spatial reference frame, and a sub-library of model arrangement descriptions, i.e., information making it possible to position a model, whatever its type, in a given spatial reference frame.

[0096] It is thus understood that the combination of a description of an element model and a description of a model arrangement, recovered at the end of step E1, thus allows the graphics engine MGi to know the position of each of the light sources of the element 21 in the spatial reference frame of the motor vehicle.

[0097] The use of these two libraries allows a single graphics engine to flexibly manage a large number of different types of elements, without increasing the RAM or buffer space it needs. It is also noted that these libraries are particularly advantageous in the context of elements 22 and 23, which are similar metrics, and can therefore be described by the same model but with different arrangements.

[0098] Similarly, the library of light sub-animation descriptions comprises a sub-library of object descriptions, in the same spatial reference as that used for the model arrangement descriptions, and a sub-library of transformation descriptions of at least one characteristic of an object.

[0099] In other words, each description D2;j of a light sub-animation recovered by the graphics engine MGi can be described by a combination of a single description Oj of an object from the sub-library of object descriptions and at least one description Tj of a transformation of a characteristic of this object from the sub-library of transformation descriptions.

[0100] It will be noted that, in the example described, an object is described, in its description Oj, by means of the number of its vertices and their positions. Furthermore, each object has properties such as a global color, a global opacity coefficient and a priority index, the values ​​of which are not fixed in the description which is stored and which define modifiable characteristics of the object by a sub-animation. The global color and / or the global opacity coefficient can be replaced by a color and / or opacity map defining a color and / or an opacity coefficient for each of the vertices. An object can thus be a geometric shape, a symbol, a pictogram, or even an entire background, or even a combination of several of these elements.

[0101] Furthermore, a transformation of a characteristic of an object is described, in its description Tj, by a starting value, an arrival value, a transformation duration and a transition profile. A transformation could thus be a change in color, opacity, position or shape of an object.

[0102] In other words, it is possible to evaluate a view, or "frame", of a light sub-animation at a given instant by applying the or each characteristic transformation, defined by the description Tj, to this characteristic of the object, as defined by the description Oj, up to this given instant. The value of this characteristic at this given instant can be obtained by interpolation, using the starting values, the arrival values, the transformation duration, the transition profile and this given instant. The representation of the object being vectorial, it is not limited to a particular resolution, so that the sub-animation is independent of the choice of structure or technology of the element 21.

[0103] The library of descriptions of light sub-animations can be stored in the memory of the graphics engine MGi in the form of a data tree A. As shown in [Fig.3], this data tree comprises a first sub-tree O encoding a plurality of descriptions of objects Oi to On; each of the descriptions comprising several characteristics Ci to Cm. The data tree also includes a second subtree T encoding a plurality of descriptions Ti to Tp of a transformation of a characteristic of an object. The library of element descriptions can also be stored in the memory of the MGi graphics engine in the form of a data tree.

[0104] At the end of steps E1 and E2, once the description Di and all the descriptions D2ij have been retrieved, the graphics engine MGi initializes a progress time for each of the corresponding light sub-animations.

[0105] In a step E3, for each sub-animation, the progress time of this sub-animation is incremented by a time step Afj, specific to this sub-animation. The steps for determining this time step Afj will be described later. This progress time is then compared to the duration 0j of the sub-animation, as defined in the description D2; j of this sub-animation.

[0106] If the progress time ty is greater than the duration 0j of the sub-animation, this sub-animation is then no longer taken into account for the subsequent steps.

[0107] Otherwise, in a step E4, the graphics engine MGi estimates the position pk of each light source of the element 21 in the spatial reference frame. It should be noted that, in the case where the element 21 is not concerned by the command Zi, none of the light sources is necessary for the display of the light animation Ai so that steps El to E9 are not implemented.

[0108] It will be noted that the positions pk may be one or more coordinates in the spatial reference frame of description D1, depending on whether the light sources of the element 21 are distributed in a one-dimensional, two-dimensional or three-dimensional manner. These coordinates may be determined by positioning the model of the element 21, as defined in description D1, in the spatial reference frame defined in the arrangement of the model of description D1, and possibly by applying transformations to this model, such as rotation, symmetry and / or a change of scale, if such transformations are defined in the arrangement of the model of description D1.

[0109] Then, in a step E5, for each description D2;j of a light sub-animation and for each position pk thus determined, the graphics engine MGi determines a value v^ of this light sub-animation at this position pk and at the advancement time f j. As described previously, the value of each of the characteristics of the object concerned by this sub-animation at this advancement time can be obtained by interpolation, so that a view of the sub-animation at this advancement time can be evaluated and the color and / or the gray level of a portion of the view of this sub-animation, at a given position and for this advancement time, can be determined. However, only the values ​​of the view at pk positions are required to display the light sub-animation on element 21. The MGi graphics engine then samples this view using the pk positions.

[0110] In a step E6, for each position pk, the graphics engine MGi determines a value ai>k of the light animation A; at this position pk using all the values ​​v^ of the light sub-animations determined at the end of step E5.

[0111] In this context, as previously explained, each description Oj of an object comprises an opacity coefficient aP defining the transparency of the object, and a priority index zj5 defining the plane in which the object appears. This opacity coefficient Oj and this priority index Zj are thus used in step E6 to be able to compose the sub-animations between them according to an alpha composition by superimposing them according to their priority indices sorted in decreasing order, each sub-animation letting the sub-animations placed below show through more or less according to its opacity coefficient.

[0112] More precisely, each value aijk of the light animation A; at a position pk can be obtained by summing the values ​​Vijjk of the light sub-animations, each value Vijjk of a light sub-animation being weighted by a coefficient determined from the opacity coefficient Oj and the priority index Zj of this light sub-animation.

[0113] [Fig.4] represents an example of implementation of steps E4 to E6 for two light sub-animations D2i and D22 evaluated at a given time t. As shown, light sub-animation D2i has an opacity coefficient ai of 1, meaning that it is completely opaque, while light sub-animation D22 has an opacity coefficient a2 of 0, meaning that it is completely transparent. Furthermore, light sub-animation D2i has a priority index Zi of 1 and light sub-animation D22 has a priority index z2 of 0, meaning that light sub-animation D2i is located above D22.

[0114] It will be noted that, despite the opacity of the sub-animation D2B, the values ​​of vi>1Jt which are zero, due to the absence of an object at their position pk, have been assigned an opacity coefficient of 0 so as to allow the values ​​vij2>k of the sub-animation D22 located below to show through.

[0115] It should be noted that the steps which have just been described are implemented for the display of a given light animation A;, following the reception of the instruction Z i. It is however possible that another light animation, or even several other light animations, is being displayed on the element 21. The operations of steps E3 to E6 as previously described can thus be implemented for other light sub-animations described by another set D2; j of sub- light animations, retrieved by the MGi graphics engine following the reception of a Zr instruction for the display of another light animation Ar, the implementation of these steps thus allowing the graphics engine to obtain values ​​ai >k of the light animation Ar at the pk positions.

[0116] Thus, in a step E7, the graphics engine MGi thus composes all the light animations A; in progress, in a similar manner to step E6, namely by an alpha composition.

[0117] For these purposes, the graphics engine MGi assigns to each light animation A; being executed an opacity coefficient and a priority index. For example, an opacity coefficient and a priority index can be assigned to a light animation A;, following receipt of the corresponding command Z; and in particular as a function of information contained in this command.

[0118] The graphics engine MGi can thus determine control instructions bk for each of the positions pk, using all the values ​​aijk of the light animations A; determined at the end of step E6. These control instructions bk are intensity and / or color instructions which are advantageously organized in a table transmitted to the controller Pi. It should be noted that the position of a control instruction bk in the table corresponds to the position pk of the light source within the element 21.

[0119] In a step not shown, the graphics engine MG1 will be able to carry out a gamma correction of each of the control instructions bk.

[0120] Steps E3 to E7 are thus repeated sequentially, for each light sub-animation of each light animation Ai, until the advance time hj of this sub-animation becomes greater than the duration 0j of this sub-animation. As indicated previously, this sub-animation is then no longer taken into account for the calculation of the following control instructions bk.

[0121] All of these cycles thus make it possible to obtain a sequence of control instructions for the display of the light animations A;. Once all of the sub-animations of a light animation A; have been executed, the animation A; is considered to be finished and is no longer taken into account for the calculation of the following control instructions bk.

[0122] Each control instruction bk thus allows the controller Pi to control the light source of the element 21 corresponding to the position pk so that it emits, or not, an elementary light beam whose intensity and / or color depends on this control instruction bk.

[0123] For these purposes, in a step E8, the controller PI can for example generate, for each light source of the element 21, one or more pulse width modulated signals, or PWM, whose duty cycles rk are determined as a function of the control instruction bkassociated with the position pk of this light source, depending on whether this instruction defines a gray level or a color

[0124] In a step E9, the light sources of the element 21 are controlled by means of PWM signals, so that all of the elementary beams emitted by the light sources of the element 21 materialize all of the light sub-animations of the animations Ai, at the advance times f j.

[0125] [Fig.5] thus shows a time graph representing different control instructions bk generated sequentially by the graphics engines MGi, MG2 and MG3 for the display of two light animations Ai and A2 on the elements 21, 22 and 23 of the light system 1.

[0126] The light animation Ai corresponding to a change in color of an ambient light emitted by the elements 21, 22 and 23, all of the light sources of these elements thus participating in this light animation Ab. The light animation A2 corresponds to the display of arrows moving from the center of the element 21 towards the end of the element 22, in order to signal to an occupant of the vehicle an event located on the right side of the vehicle. The command Z2, supplied to each graphics engine and causing the display of the animation A2 may for example result from the detection, by one or more sensors of the vehicle, of said event.

[0127] Each graphics engine MGi, MG2 and MG3 comprises a clock for sequencing the calculation of the control instructions bk. Each clock thus generates a clock signal having a period Ac and each control instruction being generated after the same cycle of periods Ac.

[0128] In the ideal example of [Fig.5], the periods Ac of the clocks are identical, so that the control instructions bk are generated by the graphics engines MGi, MG2 and MG3 synchronously.

[0129] However, it is common for the clock periods of two graphics engines to differ. In the example shown in [Fig.6], the period ACi of the graphics engine MGi is longer than the period AC2 of the graphics engine MG2.

[0130] As a result, the control instructions bk are generated by the graphics engine MGi more slowly than those generated by the graphics engine MG2I1, and as a result, the duration of the light animation A2 as displayed is shorter for the element 22 than for the element 21. Therefore, the occupant of the vehicle may observe that the scrolling speed of the arrow of the animation A2 is faster when it is displayed on the element 22 than when it is displayed on the element 21, which may be annoying.

[0131] In order to overcome this drawback, in a step E10, the master controller BCM, which is also equipped with a clock, transmits to all the graphics engines MGi, MG2 and MG3 of the lighting system 1 a data frame containing its clock signal. with its Ac period.

[0132] In a step Eli, each graphics engine compares the period of its clock signal with that of the master controller. In the example of [Fig.7], the period ACi of the graphics engine MGi is identical to the period Ac of the master controller BCM, while the period ACi of the graphics engine MG2 is shorter.

[0133] In step El 1, in the event of variation between these periods, each graphics engine thus calculates the ratio between the period Ac of the master controller BCM and its own period and determines a value of the time step Atjj used to increment the advancement time hj from this offset. More precisely, this time step Afj will be increased if the ratio is less than 1 and will be decreased if the ratio is greater than 1.

[0134] In the example of [Fig.7], the time step At2 used by the MGi graphics engine is therefore greater than the time step At'2 used by the MG2 graphics engine.

[0135] It can thus be seen that the number of cycles of steps E3 to E7 necessary for the progress time of animation A2 to be greater than the duration of this animation is greater for the graphics engine MG2 than for the graphics engine MGi. Consequently, the actual display time of animation A2 on element 22 is extended and the effect observed by the occupant in the example of [Fig.6] disappears in the example of [Fig.7],

[0136] The preceding description clearly explains how the invention makes it possible to achieve the objectives it has set itself, and in particular by proposing a method for displaying a light animation on a light system which makes it possible to test and validate this light animation, independently of the structure, design or technological choices of the light system, and which does not require significant dimensioning of a RAM and / or a buffer memory for calculating the control instructions of the light system.

[0137] In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically effective combination of these means.

Claims

Claims

1. Method for displaying a light animation on a light system (1) of a motor vehicle comprising a controller (Pb P2, P3) and a plurality of light sources selectively controllable by the controller, the method being implemented by a graphics engine (MGi, MG2, MG3) equipped with a memory in which is stored a description library (D2ij) of light sub-animations, comprising the following steps: a. step (El) of providing the graphics engine with a description (Dl) of at least one element (21, 22, 23) of the lighting system defining the number and position of the light sources of this element; b. step (EO) of reception by the graphics engine of a display command (¾) of a first light animation (A;) on the element of the light system; c. step (E2) of recovery by the graphics engine, upon receipt of said display command, of a first set of descriptions (D2jj) of light sub-animations stored in said memory and making it possible to produce said first light animation together; d. step (E3, E4, E5, E6, E7) of determining by the graphics engine a sequence of control instructions (bk) of the light sources of said element to display said first light animation, the sequence of control instructions being determined from the description of each light sub-animation of the first set, and as a function of the description of said element; e. step (E9) of controlling, by said controller, the light sources of the element of the lighting system by means of the sequence of control instructions to display said first light animation on the lighting system.

2. Method according to the preceding claim, in which the description (Dl) of said element (21, 22, 23) comprises a description of a model of said element comprising a spatial distribution of light sources of said element and a description of an arrangement of said model in a spatial reference frame.

3. Method according to one of the preceding claims, in which the set of descriptions (D2jj) of the light sub-animations is stored in said memory of the graphics engine (MGi, MG2, MG3) in the form of a data tree (A), said data tree comprises a first sub-tree (0) encoding a plurality of descriptions (Ob On ) of objects each comprising one or more characteristics (Cb Cm) of said object, and a second sub-tree encoding a plurality of descriptions (Ti, Tp) of a transformation of at least one characteristic of an object; characterized in that the step of retrieval (E2) by the graphics engine of said first set comprises the retrieval, for each sub-animation of the first set, of a description (Oj ) of an object in the first sub-tree and of a description of a transformation (Tj) of at least one characteristic of said object in the second sub-tree.

4. Method according to the preceding claim, characterized in that, for each description (Oi, On) of an object stored in said first sub-tree (0), said description comprises a value of at least one characteristic (Cl, Cm) of the object chosen from at least the following characteristics: a. number of vertices of said object; b. position of the vertices of said object.

5. Method according to the preceding claim, characterized in that, for each description of a transformation (Tb Tp) of at least one characteristic (Cl, Cm) of an object stored in said second sub-tree (T), said description comprises at least one starting value of said characteristic, one end value of said characteristic, a duration of said transformation and a transition profile of said characteristic from its starting value to its end value.

6. Method according to one of the preceding claims, in which the descriptions of the sub-animations stored in the memory are defined in the same spatial reference frame, characterized in that each instruction (bk) of said sequence of control instructions is determined sequentially from the reception of said command (¾) and in that, for each instruction of said sequence of instructions and for each light source of the element (21, 22, 23) of the light system (1), the graphics engine (MGi, MG2, MG3) determines: a. (E4) from said description (Dl) of said element, the position (pk) of said light source in said spatial reference frame; b. (E5) for each light sub-animation of the first set (D2jj), a value (Vij>k) of said light sub-animation at said determined position and at a given time (fj); c. (E6) a value (ai>k) of the first light animation (A;) at said position determined from the determined value of each light sub-animation of the first set; said instruction being determined from said determined value of the first light animation.

7. Method according to one of the preceding claims, the method comprising: a. (EO) subsequently to the reception of the display command (Z;) of the first light animation (Ai), the reception by the graphics engine (MGi, MG2, MG3) of a display command of a second light animation; b. (E2) upon receipt of said command to display the second light animation; the recovery by the graphics engine from said memory of a second set of descriptions (D2;j) of light sub-animations making it possible to produce said second light animation together; c. (E3, E4, E5, E6, E7) the determination by the graphics engine of a sequence of control instructions (bk) of the light sources of said element to display said first light animation and said second light animation, the sequence of control instructions being determined from the description of each light sub-animation of the first set, from the description of each light sub-animation of the second set, and as a function of the description (Dl) of said element (21, 22, 23).

8. A method according to claim 7 in combination with claim 6, characterized in that, for each instruction (bk) of said sequence of instructions and for each light source of the element (21, 22, 23) of the light system, the graphics engine (MGi, MG2, MG3) determines: a. (E4) from said description (Dl) of said element, the position (pk) of said light source in said spatial reference frame, b. (E5) for each light sub-animation of the first set (D2ij) and of the second set, a value (v^) of said light sub-animation at said determined position; c. (E6) a value (ai>k) of the first light animation at said position determined from the determined value of each light sub-animation of the first set and a value of the second light animation at said position determined from the determined value of each light sub-animation of the second set; said instruction being determined from said determined values ​​of the first and second light animations.

9. Method according to the preceding claim, characterized in that, for each instruction (bk) of said sequence of instructions, the graphics engine (MGi, MG2, MG3) increments a progress time (hj) of each light sub-animation of the first (D2ij) and of the second sets of sub-animations, the step (E5) of determining the value (Vij>k) of each light sub-animation of the first and of the second sub-sets at said determined position (pk) being carried out according to said progress time of this sub-animation.

10. Method according to one of the preceding claims, characterized in that the step of determining (E3, E4, E5, E6, E7) by the graphics engine (MGi, MG2, MG3) a sequence of control instructions (bk) of the light sources of said element (21, 22, 23) to display said first light animation (A,) comprises the generation of a sequence of control instructions (bk) each associated with one of the light sources of said element, the ordering of said sequence of instructions corresponding to the arrangement of the light sources said element with respect to the motor vehicle.

11. A computer program comprising program code which is designed to implement the method according to one of claims 1 to 10.

12. Data carrier on which the computer program according to claim 11 is recorded.

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