EP4064792A1 - Headlight provided with improved dynamic lighting - Google Patents

Abstract

A lamp, for example a headlamp, comprising- a light source (231);- a power module (230) for generating a power supply for the light source (231) from information or a control signal;- a control module (220) for adjusting the power generated by said light source; said control module (220) comprising:a light sensor (120) for sensing light from the environment of the holder of the lamp, the control module (220) being configured to generate the information or the control signal based on the information generated by the light sensor (110),characterized in that the control module (220) further comprises:an accelerometer (110) configured to provide at regular intervals data representative of an acceleration of the headlamp following at least a horizontal axis and a vertical axis;wherein said control module (220) comprises a circuit (221, 222, 223) configured to store and process accelerometry data in order to select a profile of physical activity selected from a set of predetermined physical activity profiles stored in a memory (223);wherein the control module (220) includes a LUT look-up table stored in said memory (223) providing the at least one value or parameter serving to generate information or the light power control signal;wherein the selected physical activity profile serves as an entry pointer in said LUT table;wherein the value or parameter read in the LUT lookup table is used in conjunction with the information generated by the light sensor to determine the light output control information or signal.

Description

Technical area

The present invention relates to the field of headlamps equipped with so-called Reactive Lighting technology, and in particular a headlamp comprising an accelerometric sensor.

State of the art

The applicant of the present patent application has marketed a portable lamp, of the headlamp type, equipped with so-called reactive or dynamic lighting, the operating principle of which is illustrated in the figure 1 . This headlamp has an electronic circuit equipped with a sensor that analyzes the external brightness to instantly deliver an adjusted lighting power and an optimal beam shape for the situation.

This type of lamp has proven to be particularly suitable for committed and intensive sports because it relieves the user of the manual mode adjustments that would be necessary to switch between different beam power thresholds.

Thanks to this reactive lighting technique ( Reactive Lighting ), the user has his hands free and his mind completely focused on his activity, whatever the lighting situation considered.

Thus, in proximity lighting , the user can thus observe or examine an object at a short distance (reading a map, making a tie-up knot or setting up a tent for example) and the lamp can protect a very wide and low-power light beam, automatically set to a minimum threshold value thanks to this dynamic lighting technique. The lighting automatically adapts to the distance of the object.

On the contrary, in a situation of movement , for example when the user engages in walking and/or running, the beam becomes mixed: wide at the level of the feet and focused to see at a few meters and anticipate the relief .

In addition, when in a situation of distant vision, the user raises his head to see far away - for example to look for a beacon during a run or even a relay attached to a wall, the power of illumination increases dramatically and the beam becomes focused to best assist the lamp user.

Finally, we note that the reactive or dynamic lighting technology ( Reactive Lighting ) has proved to be particularly economical in use and makes it possible to advantageously increase the autonomy of the batteries since its implementation, under the control of a calculator, aims to optimize battery consumption, offering greater autonomy for your lamp.

As we can see, this reactive or dynamic lighting technology is undeniably a significant advance in the field of headlamps, and more generally of portable lighting, in particular in that it allows the lighting to be constantly adapted. to lighting conditions.

However, practitioners have identified drawbacks in certain very specific situations.

In fact, in so-called trail or running activities, the presence of many reflective surfaces on shoes, technical clothing and signs cause pumping phenomena at the level of the projected light, thus degrading the quality of the lighting and revealing an area of discomfort for the user.

When the latter is cycling with his headlamp, or even other very dynamic activities (ski touring or other), the minimum level of light may in practice prove to be insufficient to guarantee safe lighting when crossing with a luminous or natural obstacle (car headlights, tree branch, etc.). The previously noted discomfort zone may then turn out to be a danger zone.

Such are the defects and disadvantages which the present invention aims to remedy.

Summary of the invention

The aim of the present invention is to propose a significant improvement to dynamic lighting technology by making it possible to take into consideration specific lighting situations requiring additional lighting.

Another object of the present invention consists in proposing a headlamp provided with the light regulation of the reactive or dynamic type having an improved adjustment of the light power.

It is another object of the present invention to provide a headlamp improved by the addition of an accelerometer which refines the reactive or dynamic regulation mechanism used by the lamp.

• une source lumineuse ;
• un module de puissance pour l'alimentation de la source lumineuse à partir d'une information ou un signal de commande;
• un module de commande pour le réglage de la puissance générée par la source lumineuse, comportant :
  un capteur de lumière permettant de capter la lumière de l'environnement du porteur de la lampe, le module de commande étant configuré pour générer l'information ou le signal de commande en fonction de l'information générée par le capteur de lumière.

The invention achieves these aims by means of a lamp, such as a headlamp, comprising

• a light source;
• a power module for powering the light source from information or a control signal;
• a control module for adjusting the power generated by the light source, comprising:
  a light sensor making it possible to capture the light from the environment of the holder of the lamp, the control module being configured to generate the information or the control signal according to the information generated by the light sensor.

The control module further comprises an accelerometer configured to supply at regular intervals data representative of an acceleration of the headlamp along at least one horizontal axis and one vertical axis; and wherein the control module includes circuitry configured to store and process accelerometry data to select a chosen physical activity profile from a set of predetermined physical activity profiles stored in a memory.

The selected physical activity profile is then used as an input pointer to read a correspondence table LUT stored in an internal memory of the lamp, and which provides at least one value or one parameter serving to generate information or the signal control fixing the light output. Thus, the value or parameter read from the lookup table LUT is used in conjunction with the information generated by the light sensor to determine the light output control information or signal.

Preferably, the set of predetermined accelerometer profiles includes profiles representative of walking, running and cycling.

Preferably, the power of the light beam set by the control unit varies between a low threshold and a high threshold, and the low threshold is set by a value which is extracted directly from the LUT look-up table from the automatically selected profile. .

Preferably, the processing of the accelerometer data allowing the selection of the predetermined profile uses a statistical processing method based on a calculation of the variance of the accelerometer data along the two horizontal axes and along the vertical axis.

In a particular embodiment, the data extracted from the LUT table make it possible to define a minimum light power threshold and a specific geometry of the light beam chosen between a wide beam, a pointed beam and/or both.

Preferably, the light is a headlamp configured to process accelerometer data to detect a user's fall in addition to their physical activity, and configured to communicate with a mobile phone for the purpose of transmitting a message of alert.

In a particular embodiment, in the event of a fall, the control module is configured to control a light alert sequence aimed at calling for help.

Description of the drawings

• La figure 1 illustre le schéma de principe de l'éclairage dynamique ou réactif.
• La figure 2 représente un mode de réalisation d'une lampe frontale conforme à la présente invention, qui incorpore un capteur de luminosité ainsi qu'un capteur accélérométrique pour fixer les seuils d'éclairage réactif ou dynamique.
• Les figures 3a à 3c illustrent les chronogrammes typiques, sur les trois axes x, y et z, des signaux accélérométriques pour trois activités physiques considérées:
  marche à pied, bicyclette et course à pied (jogging).
• Les figures 4a, 4b et 4c illustrent plus particulièrement les accélérations suivant chacun des axes xx', yy' et zz' et ce pour chacune des trois activités physiques considérées dans un mode de réalisation.
• La figure 5 illustre un mode de réalisation d'un procédé de régulation de puissance d'éclairage conforme à la présente invention.
• La figure 6 illustre le réglage du seuil minimum d'éclairage dyanmique en fonction de l'activité physique détectée.
• La figure 7 illustre un procédé de traitement du signal et de détermination du profil de mouvement du capteur d'accélération 3D
• Les figures 8A, 8B, 8C et 8D illustrent respectivement les signaux utiles du triplet (S1 _u (t, µ), S2 _u (t,µ), S3 _u (t,µ)) pour différents profils de mouvements µ0,µ1,µ2 et µ3 du capteur d'accélération 3D 110.

Other characteristics, object and advantages of the invention will appear on reading the description and the drawings below, given solely by way of non-limiting examples. On the attached drawings:

• The figure 1 illustrates the block diagram of dynamic or reactive lighting.
• The figure 2 shows an embodiment of a headlamp according to the present invention, which incorporates a luminosity sensor as well as an accelerometric sensor to set the reactive or dynamic lighting thresholds.
• The figures 3a to 3c illustrate the typical chronograms, on the three axes x, y and z, of the accelerometer signals for three physical activities considered:
  walking, cycling and running (jogging).
• The figures 4a, 4b and 4c illustrate more particularly the accelerations along each of the axes xx', yy' and zz' and this for each of the three physical activities considered in one embodiment.
• The figure 5 illustrates an embodiment of a lighting power control method according to the present invention.
• The figure 6 illustrates the adjustment of the minimum dynamic lighting threshold according to the physical activity detected.
• The figure 7 illustrates a method for processing the signal and determining the motion profile of the 3D acceleration sensor
• The figures 8A, 8B, 8C and 8D illustrate respectively the useful signals of the triplet ( S 1 _u ( t, µ ), S 2 _u ( t, µ ) , S 3 _u ( t, µ )) for different motion profiles µ 0, µ 1, µ 2 and µ 3 of the 3D acceleration sensor 110.

Description of preferred embodiments

We now describe how it is possible to significantly improve a headlamp equipped with a reactive or dynamic lighting system, such as marketed in the “RL” lamps of the company PETZL, for example the headlamps marketed under the called NAO ^™ , or SWIFT RL ^™ , and which include an automatic mechanism for regulating the power generated based on information produced by a luminosity sensor.

Thanks to the present invention, the mechanism for regulating the light power is arranged so as to integrate, in addition to the information emanating from the luminosity sensor, other additional information generated by an accelerometric sensor supplying acceleration signals on one or more X1, Y1 or Z1 axis.

A specific algorithm, which will be described in detail below, makes it possible to set lighting thresholds generated by the light power regulation system, and in particular a minimum lighting threshold.

I. General architecture

The figure 2 illustrates the general architecture of an embodiment of a lamp 100 - assumed to be frontal - comprising a reactive or dynamic light intensity regulation system based on a sensor 120 making it possible to measure the ambient luminosity and/or part of the flux reflected by the illumination of the headlamp.

The lamp 100 also comprises an accelerometric sensor, and preferably a three-dimensional (3D) acceleration sensor 110 making it possible to generate accelerometric information along at least one axis and preferably three axes X1, Y1, Z1 particularly illustrated in the figure 8 , the axes X1 and Z1 being horizontal and the axis Y1 being vertical.

More specifically, the lamp 100 comprises a power module 210 associated with a control module 220 and a lighting unit 230 comprising at least one light-emitting diode LED and, optionally, a transmitter-receiver module 240 coupled to the control module and a battery module 250 also coupled to control module 220.

In the example of the picture 2 , the lighting unit 230 comprises a single LED diode 231 equipped with its power supply circuit 232 connected to the power module 210. Clearly, several diodes could be envisaged for obtaining a high luminosity beam. In general, the LED diode(s) can be associated with its own focal optics 233 making it possible to ensure collimation of the light beam generated.

In a specific embodiment, the current supply to the diode LEDs 231 via the circuit 232, is performed by the power module under the control of information or a control signal generated by the control module 220 via a link which may take the form of a conductor or a set of conductors constituting a bus. The figure shows more particularly the particular example of a conductor 225.

The power module 210 specifically comprises all the components that are conventionally encountered in an LED lighting lamp for the production of a high intensity light beam, and in general based on Pulse Width Modulation PWM ( or Pulse Width Modulation in Anglo-Saxon literature), well known to a person skilled in the art and similar to that encountered in class D audio circuits. This PWM modulation is controlled by means of the control signal 225 generated by the control module 220. In general, it will be noted that the term " signal " mentioned above refers to an electrical quantity - current or voltage - making it possible to cause the control of the power module, and in particular the PWM modulation used to supply the LED diode 231 with current. This is only a particular embodiment, it being understood that it will be possible to substitute for the "control signal 225 " any "control information", for example logic information stored in a register and transmitted as has been said by any suitable means to the power module 210 in order to control the emission power of the light beam. The control signal can therefore be transmitted on different media depending on whether it is a signal or information. These supports can be a bus-type communication line coupling the control module and the power module or a simple electronic circuit for transferring a control voltage or current. In a particular embodiment, it is even possible to envisage the two control and power modules being integrated into a single module or integrated circuit.

A person skilled in the art will therefore easily understand that when one refers to a "control signal 225 ", one encompasses indiscriminately the realizations using an electrical control quantity - current or voltage - as well as the realizations in which the control is carried out by means of logic information transmitted within the power circuit. For this reason, reference will be made hereinafter indistinctly to signal or control information .

In general, the components that make up the power module 210 - switches and circuits - are well known to a person skilled in the art and the description will be deliberately lightened in this regard for the sake of conciseness. Of Likewise, the reader will be referred to general works dealing with the various aspects of PWM (or PWM) modulation.

Coming back to the figure 2 , it can be seen that the control module 220 comprises a processor 221 as well as volatile memories 222 of the RAM type and non-volatile (flash, EEPROM) 223 as well as one or more input/output circuits 224. The memories RAM and non-volatile are for storing data and firmware or firmware instructions. Furthermore, the non-volatile memory 223 is also used to store data representative of physical activity profiles which will be used jointly with the accelerometer data provided by the accelerometric sensor 110 as will be described later.

The headlamp also comprises a battery module 250 having a controller 252 and a battery 251 for example of the Ion-Lithium type.

In general, the control module 220 can access each of the other modules present in the lamp, and in particular the power module 210, the battery module 250, the two brightness 120 and accelerometer 110 sensors as well as , if applicable, to the communication module 240 allowing two-way (upward-downward) wireless communication with a smart phone 300 or any other wireless communication device.

The access of the control module 220 to the various components of the headlamp may take various forms, either by means of specific circuits and/or conductors or a set of conductors forming a bus. By way of illustration, the link 225 is represented in the figure 2 in the form of a conductor while a real data/address/command bus 226 is used for the exchange of information between the control module 220, the battery module 250 and the transmitter/receiver module 240. It However, this is only a particular embodiment, it being understood that a person skilled in the art may carry out various modifications and/or adaptations if necessary to take account of the requirements specific to the application envisaged.

By accessing the various modules making up the headlamp, the control module 220 can both read and collect information contained in each of these modules and/or conversely, transfer information, data and/or commands thereto, such as this will come out more clearly in the remainder of the presentation.

This is how the control module 220 can send the power module a control signal as represented by the signal transmitted on the link 225 and, more generally, can read the current value of the supply current of the diode 231 transiting via conductors 232 (via circuits and/or buses not shown in the figure).

Similarly, the control module 220 can access the battery module 250 via the bus 226 to read there either the different voltage values (depending on the charge or discharge cycle in progress) at the terminals thereof and/or the value the intensity delivered in order to be able to calculate a state of charge (SOC or State Of Charge in the Anglo-Saxon literature).

II. Communication module 240

The control module 220 comprises a communication module 240 allows a two-way wireless link with a mobile information processing system or mobile telephone 300. In a preferred embodiment, the transmitter as well as the receiver will be compatible with the Bluetooth standard, preferably with the Bluetooth 4.0 Low energy standard. In another embodiment, the WIFI or IEEE802.11 standard will be adopted instead. The module 240 includes a baseband unit (not shown) coupled to a wireless receiver and transmitter, making it possible to organize an uplink communication channel (uplink- Uplink ) to the mobile telephone 300 and, in the opposite direction , a downlink communication channel to this same phone. To this end, the communication module 240 may be required to perform various processing operations, in series or in parallel, on the digital representation of the signal received and to transmit, and in particular, operations of filtering, statistical calculation, demodulation, channel coding/decoding to make the communication robust to noise, etc. Such operations are well known in the field of signal processing, in particular when it comes to isolating a particular component of a signal, likely to carry digital information, and it does not it will not be necessary here to weigh down the exposition of the description.

Once detected, these packets are forwarded to processor 221 within control module 220.

The processor 221 is therefore responsible for interpreting the packets received as well as for formatting the packets for transmission according to a format specific to the standard used. Thus in the case of the Bluetooth Low Energy standard, these packets will have a structure around the standardized Generic Attribute Profile (GATT) which will not be detailed here. Depending on the interpretation of the data bits included in the packets received, the processor will reconstruct any information or commands received on the downlink from the mobile information processing system 300. Having interpreted this information or commands, the processor 221 will then relay or convert this information or command to the module concerned. Thus in the basic embodiment, the processor 221 identifies commands to the attention of the power module 210 in order to modify the light intensity and in reaction to this identification is capable of generating command information on the conductor 225 to destination of the power module 210 so that the latter proceeds to modify the light intensity generated by the lighting unit 230.

Further, processor 221 may also identify read requests from associated mobile information processing system 300 to cause the headlamp to send certain parameters to telephone 300 on the uplink.

These requests can thus be a request for the state of charge of the battery or the value of the current light power. In this case, the processor 221 will retrieve the necessary information directly from the module concerned and after performing any additional calculations on this information to obtain the final required information (in the case of the state of charge for example as seen above), will format a corresponding data packet for transmission by transceiver module 240.

It is clear that the picture 2 describes a basic embodiment, and that many other embodiments are possible and within the reach of a person skilled in the art. For example, in a more sophisticated mode, other modules could be added within the headlamp and these modules will also be coupled to the processor 221 via the bus 226 for example. These modules can then also exchange uplink or downlink data or commands with the associated mobile information processing system 300 which can then communicate with the headlamp and transmit various configuration commands to it by means of a dedicated application. running on smart phone. This dedicated application then makes it possible to coordinate the various functionalities of the headlamp by offering in particular a user-friendly interface by means of which the latter can either enter operating parameters, or come directly to control the headlamp or select different options to the features offered.

III. Dynamic or reactive lighting control

The control module 220 of the headlamp 100 implements a dynamic or reactive lighting technique. This technique consists of replacing the well-known manual adjustment modes - based on various pre-adjusted light power values such as low, medium or high, with a more automatic technique making it possible to leave the adjustment of the light power to the control module 220 and more specifically to a regulation algorithm executed by the processor 221 under the control of a regulation firmware stored in non-volatile memory 223.

According to the principle of dynamic or reactive lighting, the processor 221 adjusts the light power according to the value of the ambient luminosity measured by the sensor 120, for example by selecting a value chosen from a set of N predefined threshold values . Such a mechanism of regulation is therefore similar to an adjustment mechanism by discrete steps within a finite set of power values, allowing the control module 220 to control the headlamp by passing successively from one adjustment value to another value chosen from the set of predetermined values.

With a set of three predetermined adjustment values, corresponding to three powers, for example " low ", " medium " or " high ", the reactive or dynamic brightness mechanism therefore allows automatic adjustment of the headlamp to the correct value at within the N predetermined values.

In the same way, the geometry of the light beam can be adjusted automatically by the selection, via the control module 220, of a diffusion mode chosen from a set of several predetermined modes: for example wide, narrow, or both in same time.

Such dynamic or reactive regulation, by discrete steps, turns out to be simple and inexpensive to implement and allows automatic switching between predefined threshold values.

However, a person skilled in the art may consider a more sophisticated regulation mechanism based on a true servo-control integrating the value of the luminosity within a feedback loop which may or may not be linear, in order to fix the power of the light beam generated by the module 230. In this regard, error correction mechanisms could be conveniently integrated within the feedback loop, in particular a proportional (P), proportional-integral (PI) correction, or even Proportional Integral Differential (PID) etc..., used with suitable parameters.

Whatever the type of light regulation envisaged, by discrete steps or by means of a linear or non-linear servo-control, the regulation of the dynamic or reactive lighting could be advantageously improved by introducing an exploitation of the accelerometer data µx , µy and µz generated by the three-dimensional accelerometric sensor 110, as will now be described.

IV. Collaboration of the accelerometer 110 with the dynamic light regulation mechanism

The three-dimensional accelerometer module 110 provides accelerometer signals µx, µy and µz along three trigonometric axes X1, Y1 and Z1. As depicted in the figure 8 , the axes X1 and Z1 are horizontal while the axis Y1 is a vertical axis and, moreover, the axes X1 and Y1 are arranged in a sagittal plane relative to the user.

The picture 3a illustrates typical timing diagrams of the signals µx, µy and µz for a walking physical activity.

The figure 3b illustrates typical timing diagrams of the same µx, µy and µz signals for a bicycle physical activity.

Finally, the figure 3c illustrates typical timing diagrams of µx, µy, and µz signals for running physical activity.

The figure 4a illustrates more particularly the profile of the acceleration µx, while the figures 4b and 4c illustrate the profiles of the accelerations µy and µz, respectively.

As can be seen in these figures, the profiles of these accelerations µx, µy and µz are very characteristic and are clearly distinguished according to the three physical activities considered: Walking; bicycle or bicycle; running or jogging.

In order to significantly improve the reactive or dynamic regulation mechanism, the headlamp control module 100 is configured to come and execute a method for detecting a physical activity profile, detected within a set of N predetermined profiles.

In this respect, the control module 220 is configured in such a way that the non-volatile memory 223 comprises a memory zone in which is stored data representative of several physical activity profiles, and preferably the data representative of the activities " walking ", " running " and " cycling ". Furthermore, the non-volatile memory 223 also comprises a zone intended for the storage of a micro-program allowing the processing of the accelerometer data µx, µy and µz generated on the fly by the 3D accelerometric module 110. This algorithm goes, as it will be detailed later in relation to the figure 5 , comparing the data µx, µy and µz generated in real time with data stored in memory 223 which are characteristic of the predetermined profiles (walking, cycling, running) stored in the memory. The algorithm aims to reconcile, at regular intervals, the accelerometer data with a determined profile so as to bring the signals generated by the accelerometer into the predefined physical activity category, i.e. that corresponding to the different profiles stored in the memory of the headlamp.

The figure 5 illustrates a light regulation method in accordance with the present invention, based jointly on the detection of the ambient luminosity of the exploitation of accelerometer data.

In a step 510, the method generates at regular intervals, for example every 20 milliseconds, a set of accelerometer data µx, µy and µz supplied by the 3D accelerometer module 110. Optionally, the method may be limited to only part of the accelerometer data, for example the single datum µy along the vertical direction Y1.

In a step 520, the method performs the storage of the data µx, µy and µz within the random access memory RAM 222.

Then, in a step 530, the accelerometer data µx, µy and µz undergo digital processing making it possible to select a physical activity profile within a set of N predetermined profiles stored in memory not -volatile 223. Several methods can be used to carry out the selection or detection of the physical activity profile and will be described in more detail in section V of the present description.

In a step 540, the method uses the profile selected in step 530 as an input pointer to access a look-up table (LUT -Look-up table ) in which are stored values and parameters specific to the regulation mechanism dynamic or reactive applied by the control module 220 of the headlamp 100, and allowing the generation of the information or the control signal 225 transmitted to the power module 210.

In a particular embodiment, the parameters read in the correspondence table LUT correspond to threshold values loaded into registers used by the reactive or dynamic regulation algorithm.

More specifically, the parameters are reduced to a threshold value corresponding to a minimum of lighting considered by the dynamic regulation algorithm.

Alternatively, in the case where the dynamic regulation algorithm uses a set of distinct registers in which are stored threshold values corresponding to various brightnesses, the reading of the correspondence table makes it possible to provide these threshold values. Thus, according to the accelerometric data µx, µy and µz, are defined the minimum value of the luminosity, but possibly also the maximum value of the light power.

As will be understood, a person skilled in the art will be able to conceive various variants in the use of the values extracted from the correspondence table. It should be noted that these values may be used to set more general parameters than thresholds, and in particular variables used in automatic linear or non-linear regulation mechanisms, for example parameters or integral, or proportional-integral etc. correction variables, in order to more finely adapt the reactive or dynamic regulation mechanism to the physical activity profile detected.

Then in a step 550, the method reads the LUT table and extracts the parameter(s) stored therein and, in the case of the preferred embodiment which is particularly economical to implement, the method extracts the minimum threshold value that should be applied to the reactive or dynamic light regulation mechanism.

In a step 560, the reactive or dynamic light regulation mechanism is executed by using the value(s) extracted from the LUT table so as to precisely adapt this regulation, and if necessary the feedback loop. reaction coming to fix the light power generated by the headlamp to adapt it to the physical activity identified in step 530. Thus the control information or the control signal transmitted via the conductor 225 is generated from the value or values extracted from the LUT, together with the information provided by the light sensor 120.

In the preferred embodiment based on the reading of a single minimum threshold value within the LUT table, the dynamic or reactive regulation is therefore applied so as to ensure, in all cases, a minimum light power corresponding to the threshold value extracted from the LUT table.

It should be noted that various variants may be envisaged by a person skilled in the art and in particular variants relating to the adjustment of the geometry of the beam. Indeed, the LUT table may conveniently include, in addition to the minimum threshold value mentioned above, one or more additional parameters making it possible to fix the geometry of the beam, and in particular the fact of using a wide or narrow collimation, or even a combination both. Provision could even advantageously be made to extract from the LUT table the proportions of distribution of the light power over the three wide, mixed and pointed beams as a function of the physical activity detected.

Then, in a step 570, the method loops to step 510 to read and process new accelerometer data µx, µy and µz.

As can be seen, the reactive or dynamic light regulation mechanism is advantageously enriched by the contribution of accelerometer data obtained on the fly from the accelerometer 110, and which the control module 220 processes to bring the processed data closer to a predetermined physical activity profile stored in the non-volatile memory 223 which, once identified, makes it possible to consult the LUT table so as to extract the most appropriate parameters and adjustment values for the light regulation.

In this way, it is possible to advantageously cooperate the use of the ambient luminosity captured by the sensor 120 with the raw accelerometric data µx, µy and µz generated directly by the 3D accelerometric sensor 110.

The figure 6 illustrates the effect of the process which has just been described in which it is seen that the low level threshold set without the contribution of accelerometry data remains at the same level whatever the activity considered, for example walking (part left of the figure), running (middle part of the figure) and cycling or mountain biking (right part of the figure). If this low level does not pose any difficulty for a walking-type activity, we observe on the other hand that this same low level presents a zone of discomfort for a running activity and even becomes a danger zone for a mountain biking-type activity. .

As just described, the process described in figure 5 makes it possible to mount the low level threshold, to adapt it to a first higher level for a running activity and to mount it to an even higher second level for a mountain biking type activity, so that the user does not is never in the discomfort zone represented in the middle part of the figure 6 and even less in the danger zone of the right part of this same figure.

It can therefore be seen in the end that the method allows finer adaptation of the light power determined according to a reactive or dynamic regulation method, which takes account of the profile of physical activity considered.

It should be noted that a set of three activity profiles has been described but that the invention could conveniently be used for a higher number of profiles (climbing, alpine skiing, Nordic skiing, etc.).

V. Physical activity detection method

• .- un premier accéléromètre élémentaire, configuré pour mesurer l'évolution d'une première composante d'accélération µx, longitudinale, de la lampe suivant un premier axe (X1) sensiblement parallèle à la direction du mouvement de la lampe,
• .- un deuxième accéléromètre élémentaire, configuré pour mesurer l'évolution d'une deuxième composante d'accélération µy, verticale, de la lampe suivant un deuxième axe (Y1) sensiblement parallèle à la direction verticale terrestre locale,
• .- un troisième accéléromètre élémentaire, configuré pour mesurer l'évolution d'une troisième composante d'accélération µz, latérale, suivant un troisième axe (Z1) perpendiculaire aux premier et deuxième axes.

The detection of physical activity is based on a 3D three-dimensional acceleration sensor 110 which comprises three elementary accelerometers:

• .- a first elementary accelerometer, configured to measure the evolution of a first component of acceleration µx, longitudinal, of the lamp along a first axis (X1) substantially parallel to the direction of movement of the lamp,
• .- a second elementary accelerometer, configured to measure the evolution of a second component of acceleration µy, vertical, of the lamp along a second axis (Y1) substantially parallel to the local terrestrial vertical direction,
• .- a third elementary accelerometer, configured to measure the evolution of a third component of acceleration µz, lateral, along a third axis (Z1) perpendicular to the first and second axes.

The X1 and Y1 axes are placed in a sagittal plane relative to the user.

Each elementary accelerometer is configured to provide a time series of elementary acceleration values along their corresponding axis. The first time series, supplied by the first elementary accelerometer, forms a first elementary raw signal, designated by S 1 _b ( t,µ ), which varies according to time t and the motion profile µ of the 3D acceleration sensor by relative to the local terrestrial reference. The second time series, provided by the second elementary accelerometer, forms a second elementary raw signal, denoted by S 2 _b ( t,µ ), which varies as a function of time t and of the motion profile µ of the 3D acceleration sensor relative to the local terrestrial reference. The third time series, supplied by the third elementary accelerometer, forms a third elementary raw signal, denoted by S 3 _b ( t,µ ) , which varies as a function of time t and of the motion profile µ of the 3D acceleration sensor by relative to the local terrestrial reference. The movement profile µ of the 3D acceleration sensor is for example that of a walker, designated by µ 1, that of a cyclist, designated by µ 2, or that of a runner, designated by µ 3. As illustrated in particular in the figures 8a to 8d .

The control module 220 comprises a digital electronic circuit - which could advantageously be produced by means of the processor 221 associated with its memory or by means of any other specialized digital signal processor (DSP ) and which is configured to process only one or at least two of the raw signals S 1 _b ( t, µ ), S 2 _b ( t, µ ), S 3 _b ( t, µ ) supplied by the 3D acceleration sensor according to a method 700 or algorithm of signal processing and determination of the movement profile of the 3D acceleration sensor illustrated in the figure 7 , and finally allowing the detection of the physical activity useful to the method of the figure 5 .

The 700 process of the figure 7 includes an initial optional filtering step 710, followed by a feature extraction step 720, then a decision step 730 by thresholding.

In the initial step 710 of the processing method 700, designated as the " filtering step ", one or more of the raw signals S 1 _b ( t,µ ), S 2 _b ( t,µ ), S 3 _b ( t , µ ) are respectively filtered into new signals, called useful signals and denoted by S 1 _u ( t,µ ) , S 2 _u ( t,µ ) , S 3 _u ( t,µ ), in which the useful information is still present but where the harmful information, called "noise" (here electronic noise from the 3D acceleration sensor), is either suppressed or weakened. The global information contained in the signal therefore has a certain degree of specialization at this level. In the case where the initial filtering step 710 is omitted, the raw signals S 1 _b ( t,µ ), S 2 _b ( t,µ ), S 3 _b ( t,µ ) are respectively identical to the useful signals S 1 _u ( t,µ ), S 2 _u ( t,µ ), S 3 _u ( t,µ )

Following the Figures 8A, 8B, 8C and 8D the useful signals of the triplet ( S 1 _u ( t,µ ), S 2 _u ( t,µ ) , S 3 _u ( t,µ )) are illustrated respectively for different motion profiles µ 0, µ 1, µ 2 and µ 3 of the 3D acceleration sensor 110.

Following the Figure 8A , the useful signals S 1 _u ( t,µ 0), S 2 _u ( t,µ 0) and S 3 _u ( t,µ 0), respectively illustrated on a first curve 802, a second curve 804, a third curve 806, are typically those of a 3D acceleration sensor having the form 808 of a reference movement profile µ 0 , corresponding to a movement of low amplitude or almost zero of the 3D acceleration sensor.

Following the Figure 8B , the useful signals S 1 _u ( t,µ 1), S 2 _u ( t,µ 1) and S 3 _u ( t,µ 1), respectively illustrated on a fourth curve 822, a fifth curve 824 and a sixth curve 826 are typically those of a 3D acceleration sensor having the form 828 of a motion profile μ 1 of a walker.

Following the Figure 8C , the useful signals S 1 _u ( t,µ 2) , S 2 _u ( t,µ 2) and S 3 _u ( t,µ 2), respectively illustrated on a seventh curve 842, an eighth curve 844 and a ninth curve 846 are typically those of a 3D acceleration sensor having the form 848 of a movement profile μ 2 of a cyclist (in English “biking”).

Following the Figure 8D , the useful signals S 1 _u ( t,µ 3) , S 2 _u ( t,µ 3) and S 3 _u ( t,µ 3), illustrated respectively on a tenth curve 862, an eleventh curve 864 and a twelfth curve 866 are typically those of a 3D acceleration sensor having the form 868 of a motion profile µ 3 of a runner (in English “jogging”).

The object of the feature extraction step 720 is to extract from at least one of the useful signals S 1 _u ( t,µ ), S 2 _u ( t,µ ), S 3 _u ( t,µ ) a finite set of several parameters, if possible independent, representative of the observed phenomenon, and allowing it to be described.

The extraction of characteristics implemented in step 720 allows in other words the passage of a useful vector or scalar signal to data. The difference between these two types is important: a signal can be seen as a set of points for which each point has a high degree of dependence (deterministic or statistical) with its neighbors. Data represent a set of points where this notion of neighborhood is less important. In reality, the transition from signal to data most often takes place in several stages. The intermediate entities then carry either the name of signal, estimator, or data. The main goal of feature extraction is to obtain, from the useful signal, mutually independent data that exhaustively represent the phenomenon to be interpreted.

In general, the useful signals studied here can be characterized by elementary estimators which are the moments of these signals: the mean (moment of order 1), and the pseudo-standard deviation (moment of order 2) are the better known and more widely used. For example, an estimator can be a function of one or more moments of the same useful signal.

dans laquelle :

• .-Nech désigne le nombre total d'instants d'échantillonnage équiréparties dans la fenêtre d'échantillonnage courante,
• .- mS2 désigne la moyenne statistique du signal utile S2 calculée dans la fenêtre d'échantillonnage courante calculée à partir des mesures de signal utile S2 aux mêmes instants d'échantillonnage tk.

According to a first embodiment, the useful signal S 2 _u ( t,µ ) which measures the evolution of the second component of vertical acceleration of the lamp can characterize on its own the movement profile of the lamp from its moment of order 2, that is to say its variance. According to the first embodiment, the estimator making it possible to characterize the movement profile of the lamp is written over a current and sliding sampling window of predetermined duration T _is by the following equation: $$\mathit{<figure-callout\; id="2"\; label="East\; S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">East\; </figure-callout>}\left(S\right)\left(2\right)\left(\mathit{\mu }\right)={\displaystyle \sum _{k=1\mathit{in\; <figure-callout\; id="2"\; label="Nech\; S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">Nech</figure-callout>}}}{\left(S\right)}^{}{\left(2\left(\mathit{tk},\mathit{\mu }\right)-\mathit{<figure-callout\; id="2"\; label="mS"\; filenames="imgf0004.png"\; state="\{\{state\}\}">mS</figure-callout>}2\right)}^2/\mathit{Nech}$$

in which :

• .-Nech designates the total number of equally distributed sampling instants in the current sampling window,
• .- mS2 designates the statistical mean of the useful signal S2 calculated in the current sampling window calculated from the measurements of useful signal S2 at the same sampling instants tk.

Here the elementary estimator considered Est(S2) is the statistical variance of the useful signal S 2 _u ( t,µ ) .

Then, in the decision step 730 by thresholding, the type of displacement profile of the lamp is determined by thresholding on the East estimator ( S 2)( μ ).

These elementary estimators taken in isolation may not always be sufficient to provide a good description of a complex problem. In order to systematically choose estimators that are consistent and useful for the interpretation of a signal, more sophisticated analysis methods may prove to be useful.

For complex problems, efficient feature extraction is very often reduced by statisticians to determining the dimension of the problem. This dimension is given by the minimal number of parameters allowing to represent the problem in an exhaustive way. These parameters are then called problem variables. By definition these variables are variables are independent of each other, this decreases the dimension of the problem by 1. In practice, for complex problems, it is very difficult to construct the vector of variables. In fact, it is rare for the estimators that we know how to extract from a signal to be totally independent of each other. Moreover, the construction of these estimators requires a “perfect” mathematical model of the problem (in the sense of physics), which is not always possible. A certain number of analysis methods make it possible to extract, to construct a vector of parameters from any vector. These methods are grouped under the generic term factor analysis.

• .- l'analyse en composantes principales,
• .- l'analyse factorielle des correspondances,
• .- l'analyse factorielle des correspondantes multiples
• .- l'analyse factorielle discriminante,
• .- la régression linéaire,
• .- la classification par k-moyennes (en anglais k-means),
• .- la caractérisation par géométrie fractale.

Factor analysis proceeds from a geometric reasoning on the data. We consider the signal as a “cloud of points” in an N-dimensional space, and we seek to determine the geometric characteristics of this cloud: main axes (eigenvectors), spreading, form factors, etc. , the approach is to calculate the eigenvectors of the point cloud, then to change space, so as to express the coordinates of the points of the cloud, as well as all the relations known on these points, in the space of the eigenvectors . Among the statistical methods of factor analysis are:

• .- principal component analysis,
• .- factorial analysis of correspondences,
• .- factorial analysis of multiple correspondents
• .- discriminant factor analysis,
• .- linear regression,
• .- the classification by k-means (in English k-means),
• .- characterization by fractal geometry.

dans laquelle les paramètres a, b, c sont déterminés par apprentissage sur le signaux utiles d'apprentissages {S1 _u (t,µ0), S2 _u (t,µ0), S3 _u (t,µ0), {S1 _u (t,µ1), S2 _u (t,µ1), S3 _u (t,µ1), {S1 _u (t,µ2),S2 _u (t,µ2)t,),S3 _u (t,µ2), et {S1 _u (t,µ3),S2 _u (t,µ3) et S3 _u (t,µ3).For example, according to a second embodiment, the dimension of the problem of estimating the displacement profile of the lamp is considered equal to 3. The three elementary variables are formed by the respective statistical variances Est(S1)(µ), Est (S2)(µ), Est(S3)(µ), useful signals S 1 _u ( t,µ ), S 2 _u ( t,µ ), S 3 _u ( t,µ ) . A scalar estimator denoted Est(S1,S2,S3)(µ) of the useful vector signal ( S 1 _u ( t,µ ) , S 2 _u ( t,µ ) , S 3 _u ( t,µ )) is determined as a linear combination of the statistical variances Est(S1)(µ), Est(S2)(µ), Est(S3)(µ) according to the equation: $$\mathit{<figure-callout\; id="1"\; label="East\; S"\; filenames="imgf0004.png,imgf0007.png"\; state="\{\{state\}\}">East\; </figure-callout>}\left(S\right)\left(1,\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">S</figure-callout>}2,\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">S</figure-callout>}3\right)\left(\mathit{\mu }\right)=\mathrm{has}\ast \mathit{<figure-callout\; id="1"\; label="East\; S"\; filenames="imgf0004.png,imgf0007.png"\; state="\{\{state\}\}">East\; </figure-callout>}\left(S\right)\left(1\right)\left(\mathit{\mu }\right)+b\ast \mathit{<figure-callout\; id="2"\; label="East\; S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">East\; </figure-callout>}\left(S\right)\left(2\right)\left(\mathit{\mu }\right)+\mathrm{vs}<figure-callout\; id="3"\; label="\ast \; East\; S"\; filenames="imgf0004.png"\; state="\{\{state\}\}">\ast </figure-callout>\mathit{East}\left(S\right)\left(3\right)\left(\mathit{\mu }\right)$$

in which the parameters a, b, c are determined by learning on the useful learning signals { S 1 _u ( t, µ 0), S 2 _u ( t, µ 0), S 3 _u ( t, µ 0) , { S 1 _u ( t,µ 1), S 2 _u ( t,µ 1) , S 3 _u ( t,µ 1), { S 1 _u ( t,µ 2) ,S 2 _u ( t,µ 2) t,),S 3 _u ( t,µ 2), and { S 1 _u ( t , µ 3), S 2 _u ( t,µ 3) and S 3 _u ( t,µ 3).

Then, in the decision step 308 by thresholding, the type of displacement profile of the lamp is determined by thresholding on the scalar estimator East ( S 1 , S 2, S 3)( μ ).

It should be noted that these more complex embodiments, resorting to the combination of several variables, make the detection method more robust, in particular with regard to a possible rotation of the user's head with respect to one of the axes.

VI. Additional improvements and advantages of the invention

In a preferred embodiment, the physical activity profile identified by the control module 220 is transmitted by the wireless link to the mobile telephone 300 so that the latter can inform, at any time, of the activity physical activity detected automatically according to the above technique to, if necessary, allow the user to come and correct the detection and allow adaptive learning of the method for detecting physical activity.

Furthermore, in a particular embodiment, the headlamp is configured to read accelerometer data µx, µy and µz on the fly to determine the fall of the user and, in this case, to trigger a procedure of emergency. In particular, the procedure may be based on the sending of an alert signal to the mobile telephone so as to initiate the generation of an emergency message, of the SMS or e-mail type.

Alternatively, or cumulatively, the alert procedure will include the activation of the lamp for the generation of an alert light sequence, such as for example a MORSE coding of the well-known sequence S.O.S.

Any other alert procedure may be envisaged once the control module 220 of the headlamp has detected the fall of the user.

Finally, it is useful to note that the invention is not limited to headlamps alone and may be used applied to a hand lamp.

Claims (11)

Lamp (100) comprising - a light source (231) comprising one or more LED-type diodes; - a power module (230) for generating a current supply to said light source (231), said power module being controlled by information or a control signal; - a control module (220) for adjusting the light intensity generated by said light source; said control module (220) comprising: a light sensor (120) for sensing light from the environment of the lamp holder, said control module (220) being configured to generate said information or said control signal according to the information generated by the sensor of light (110), characterized in that said control module (220) further comprises: an accelerometer (110) configured to supply at regular intervals data representative of an acceleration of the headlamp along at least one horizontal axis and one vertical axis; wherein said control module (220) includes circuitry (221, 222, 223) configured to digitally store and process data representative of said acceleration and to select a selected physical activity profile from a set of physical activities stored in a memory (223); wherein said control module (220) comprises a LUT look-up table stored in said memory (223) providing at least one control setting value or parameter for generating said information or said control signal; wherein the physical activity profile selected by said circuit (221, 222, 223) serves as an entry pointer into said LUT; wherein the value or parameter read from said LUT is used in conjunction with information generated by the light sensor to determine said information or said control signal. Lamp according to Claim 1 , characterized in that the said accelerometer (110) generates accelerometer data along two horizontal axes X1, Z1 and along a vertical axis Y1; and
wherein the set of predetermined accelerometry profiles include profiles representative of walking, running and bicycling. Lamp according to Claim 1 , characterized in that the power of the light beam adjusted by the control unit (220) varies between a low threshold and a high threshold, the low threshold being fixed by a value extracted directly from the said LUT table. Lamp according to Claim 1 , characterized in that the said circuit (221, 222, 223) configured to store and process data representative of the said acceleration uses a digital and statistical processing method based on the measurement of the variance of the vertical acceleration component µy of the headlamp. Lamp according to Claim 4 , characterized in that the said circuit (221, 222, 223) configured to store and process data representative of the said acceleration uses a digital and statistical processing method based on the measurement of the variance of two acceleration components. of the headlamp. Lamp according to Claim 1 , characterized in that the data extracted from the LUT table make it possible to define a minimum light power threshold and a specific geometry of the light beam chosen between a wide beam, a pointed beam and/or both. A lamp according to claim 1 characterized in that said lamp is a headlamp and said control circuit (220) is configured to process accelerometer data to detect a user's fall. Lamp according to Claim 6, in which the said control module transmits the user's fall information in order to generate an electronic alert transmitted to the mobile telephone. Lamp according to Claim 7, in which the control module is configured to control a light alert sequence aimed at calling for help. A light regulation method for a headlamp as defined in one of the preceding claims, comprising the steps: - generating (510) at regular intervals a set of accelerometer data µx, µy and µy provided by said accelerometer; - storing (520) said data µx, µy and µy within a random access memory (222); - performing digital processing (530) on said accelerometer data µx, µy and µy in order to select a physical activity profile from a set of N predefined profiles stored in non-volatile memory (223); - using (540) the selected profile as an input pointer to access a LUT correspondence table in which are stored values and parameters specific to the mechanism allowing the generation of said information or of said control signal used to adjust the light power ; - reading the LUT table (550) and extracting the parameter(s) or values stored therein; - determining said control information or said control signal from the value or values extracted from the LUT, together with the information provided by said light sensor (120); - return to the first step to read and process new accelerometer data. Method according to Claim 9 , characterized in that the reading of the LUT correspondence table provides a value defining the minimum power generated by the headlamp.

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