EP4287778A1 - Lighting control system, method and device for controlling at least one light source - Google Patents

Abstract

This method of controlling at least one controllable light source (L) is implemented by a control device (P). It comprises steps of: - reception (P40), from at least one brightness sensor (C), of a message (msg) comprising information (r, g, b) representative of a color of a light captured by said at least one sensor; - checking (P60) if the color of the light captured by said at least brightness sensor (C) is in a range (P_COL) of colors of preference associated with said at least one sensor (C); and when this is not the case: - sending (P70) to at least one controllable light source (L), at least one control command (comm(r_Q, g<sub >Q</sub>,b_Q)) with parameters (r_Q,g_Q,b<sub>Q</sub >) of color to modify a color emitted by said light source according to said parameters (r_Q, g_Q, b_Q) so as to that the light detected by said at least one brightness sensor (C) is included in or approaches the range of colors preferably associated with this brightness sensor (C).

Description

Background of the invention

The present invention relates to the field of lighting control, in particular but not limited to a domestic environment.

• l'allumage ou l'extinction automatique d'une ampoule en fonction de la détection d'une présence dans une pièce ;
• l'ajustement par l'utilisateur de la lumière émise par une ampoule dans un spectre de couleurs, par exemple 16 millions de couleurs différentes.

The use of remotely controllable bulbs has become widespread in recent years and allows in particular:

• the automatic switching on or off of a bulb depending on the detection of a presence in a room;
• the user's adjustment of the light emitted by a bulb into a spectrum of colors, for example 16 million different colors.

Systems also allow the adjustment of light diffused by a bulb or by a smartphone screen depending on the time of day and/or geolocation.

But these solutions do not make it possible to control the light actually perceived by the user.

1. [1] A.J. Metz, S.D. Klein, F. Scholkmann, et al. Continuous coloured light altered human brain haemodynamics and oxygénation assessed by systemic physiology augmented functional near-infrared spectroscopy. In Nature Scientific Reports 7, 2017 .
2. [2] G. Hoffmann, V. Gufler, A. Griesmacher, C. Bartenbach, M. Canazei, S. Staggl, W. Schobersberger. Effects of variable lighting intensities and colour températures on sulphatoxymelatonin and subjective mood in an experimental office workplace. In Applied Ergonomics, vol. 39 issue 6, 2008 .

However, it has been shown to have a significant impact on human physiology, particularly in studies:

1. [1] Metz AJ, Klein SD, Scholkmann F, et al. Continuous colored light altered human brain haemodynamics and oxygenation assessed by systemic physiology augmented functional near-infrared spectroscopy. In Nature Scientific Reports 7, 2017 .
2. [2] G. Hoffmann, V. Gufler, A. Griesmacher, C. Bartenbach, M. Canazei, S. Staggl, W. Schobersberger. Effects of variable lighting intensities and color temperatures on sulphatoxymelatonin and subjective mood in an experimental office workplace. In Applied Ergonomics, vol. 39 issue 6, 2008 .

The invention aims to improve existing solutions.

Object and summary of the invention

• réception, en provenance d'au moins un capteur de luminosité, d'un message comportant des informations représentatives d'une couleur d'une lumière captée par ledit au moins un capteur ;
• vérification si la couleur de la lumière captée par ledit au moins capteur de luminosité est dans une plage de couleurs de préférence associée audit au moins un capteur ; et lorsque ce n'est pas le cas :
• envoi à au moins une source lumineuse pilotable, d'au moins une commande de pilotage comportant des paramètres de couleur pour modifier une couleur émise par ladite au moins une source lumineuse selon lesdits paramètres de sorte à ce que la lumière détectée par ledit au moins un capteur de luminosité soit comprise ou se rapproche de la plage de couleurs de préférence associée à ce capteur de luminosité.

Thus, and according to a first aspect, the invention relates to a method of controlling at least one controllable light source implemented by a control device, said method comprising steps of:

• reception, from at least one brightness sensor, of a message comprising information representative of a color of light captured by said at least one sensor;
• checking whether the color of the light captured by said at least one brightness sensor is in a range of colors preferably associated with said at least one sensor; and when this is not the case:
• sending to at least one controllable light source, at least one control command comprising color parameters to modify a color emitted by said at least one light source according to said parameters so that the light detected by said at least one brightness sensor is included in or approaches the range of colors preferably associated with this brightness sensor.

• un module de communication configuré pour recevoir, en provenance d'au moins un capteur de luminosité, un message comportant des informations représentatives d'une couleur d'une lumière captée par ledit au moins un capteur ;
• un contrôleur configuré pour vérifier si la couleur de la lumière captée par ledit au moins capteur de luminosité est dans une plage de couleurs de préférence associée audit au moins un capteur ; et lorsque ce n'est pas le cas pour contrôler ledit module de communication pour qu'il envoie à au moins une source lumineuse pilotable, au moins une commande de pilotage comportant des paramètres de couleur pour modifier une couleur émise par ladite au moins une source lumineuse selon lesdits paramètres de sorte à ce que la lumière détectée par ledit au moins un capteur de luminosité soit comprise ou se rapproche de la plage de couleurs de préférence associée à ce capteur de luminosité.

Correlatively, the invention also relates to a control device comprising:

• a communication module configured to receive, from at least one brightness sensor, a message comprising information representative of a color of light captured by said at least one sensor;
• a controller configured to check whether the color of the light captured by said at least one brightness sensor is in a color range preferably associated with said at least one sensor; and when this is not the case to control said communication module so that it sends to at least one controllable light source, at least one control command comprising color parameters to modify a color emitted by said at least one source light according to said parameters so that the light detected by said at least one brightness sensor is included in or approaches the range of colors preferably associated with this brightness sensor.

The invention also relates to a lighting control system comprising at least one control device as mentioned above, at least one brightness sensor and at least one controllable light source.

• « source lumineuse pilotable », une source lumineuse configurée pour pouvoir recevoir une commande et pour émettre une couleur définie par cette commande ;
• « dispositif de pilotage », tout dispositif configuré pour pouvoir envoyer une commande à une source lumineuse pilotable pour modifier la couleur émise par cette source lumineuse ; et
• « capteur de luminosité », tout capteur de luminosité configuré pour capter les couleurs de la lumière qu'il reçoit ;
• « plage de couleurs de préférence associée à un capteur », une plage de couleurs dans laquelle on souhaite que se trouve la couleur de la lumière captée par ce capteur.

In this document, we will call:

• “controllable light source”, a light source configured to be able to receive a command and to emit a color defined by this command;
• “control device”, any device configured to be able to send a command to a controllable light source to modify the color emitted by this light source; And
• “brightness sensor” means any brightness sensor configured to capture the colors of the light it receives;
• “range of colors preferably associated with a sensor”, a range of colors in which we want the color of the light captured by this sensor to be located.

The particular embodiments and advantages of the control method presented below apply in the same way to the control device and the lighting control system.

Thus, and in general, the invention can be implemented in a room to adjust the light emitted by one or more light sources so that the color of the light captured by sensors installed in different locations conforms to or tends towards a range of colors preferably associated with each of these sensors.

The invention provides dynamic adjustment to counteract variations in light that may occur in the environment of the lighting control system. For example, when the system is implemented in a room, the control method can vary the color of the light emitted by one or more light sources when the light varies in the room. room (opening or closing of a curtain or shutter, weather change, lighting broadcast by a television, etc.).

Advantageously, the sensors can be placed in different locations and associated with preference ranges of different colors. For example, in a living room with a kitchen area and a reading area, a sensor installed in the kitchen area can be associated with a relatively cold color range and a sensor installed in the reading corner can be associated with a relatively warm color range. Of course, the sensors placed in different locations can be associated with preferably identical color ranges.

In one embodiment, the parameters of the control command are determined by a gradient descent.

This embodiment of the invention makes it possible to gradually change the lighting of the controllable light sources towards their preferred color ranges.

For the implementation of the invention, the sensors can produce color information in any format and the color parameters sent to the light sources to control them can be in any format. These formats may be the same or different.

• les messages reçus des capteurs de luminosité comportent les composantes rouge, verte et bleue des couleurs captées par ces capteurs ; et
• les commandes de pilotage envoyées aux sources lumineuses comportent les composantes rouge, verte et bleue des couleurs à émettre par ces sources.

In one embodiment of the invention, this format is identical and conforms to the RGB format. So :

• the messages received from the brightness sensors include the red, green and blue components of the colors captured by these sensors; And
• the control commands sent to the light sources include the red, green and blue components of the colors to be emitted by these sources.

In one embodiment, the information received representative of the color captured by said at least one brightness sensor is in a first format, and the control method further comprises a step of converting said information into a second color format, said gradient descent being implemented in a color space conforming to this second color format.

For example, in one embodiment, said information representative of a color captured by said at least one brightness sensor is in RGB format and converted to HSV format.

Indeed, it was advantageously determined by the inventors that the HSV format allowed a spatial representation of colors more suited to the implementation of gradient descent than the RGB format.

In one embodiment, the control method comprises, upon receipt of an activation signal coming from said controllable light source, sending a control command to this controllable light source so that it emits light with a default color, for example white at 6000K. This embodiment makes it possible to initialize the sources controllable light fixtures with neutral light before this is dynamically adjusted in accordance with the preferred color ranges.

In one embodiment, said verification step takes into account an average of the color of the light captured by said at least brightness sensor over a period of time, for example over one minute. This embodiment avoids adjusting the light emitted by the controllable light sources too frequently, for example in reaction to a flash of light produced by a television screen.

In one embodiment, the control method comprises a step of emitting an alarm if a power of the light received by said at least one sensor is less than a threshold. This embodiment makes it possible to inform a user that a light sensor is obstructed by an obstacle for example.

In a particular embodiment, the different stages of the control method are determined by computer program instructions or are implemented by a silicon chip which comprises transistors adapted to constitute logic gates of non-programmable hardwired logic.

Consequently, the invention also relates to a computer program on an information medium, this program being capable of being implemented in a controller computer, this program comprising instructions adapted to the implementation of the steps of a control method as described above.

This program may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable shape.

The invention also relates to an information medium readable by a computer, and comprising instructions for a computer program as mentioned above. The information carrier can be any entity or device capable of storing the program. For example, the medium may include a storage means, such as a ROM, a non-volatile memory of the flash type or even a magnetic recording means, for example a hard disk. On the other hand, the information carrier may be a transmissible medium such as an electrical or optical signal, which may be carried via an electrical or optical cable, by radio or by other means. The program according to the invention can in particular be downloaded onto an Internet type network. Alternatively, the information carrier may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in executing the method in question.

Brief description of the designs:

• [Fig. 1] La figure 1 représente un système de contrôle d'éclairage conforme à un mode particulier de réalisation de l'invention;
• [Fig. 2] La figure 2 représente, sous forme d'ordinogramme, des étapes d'un procédé de contrôle d'éclairage conforme à l'invention;
• [Fig. 3] La figure 3 représente un point dans un espace de couleurs correspondant au format HSV;
• [Fig. 4] La figure 4 illustre notamment une zone représentative d'une plage de couleurs de préférence associée à un capteur de luminosité;
• [Fig. 5] La figure 5 illustre un changement de la couleur de la lumière détectée par un capteur de luminosité;
• [Fig. 6] La figure 6 illustre une descente de gradient pouvant être mise en oeuvre dans un mode particulier de réalisation;
• [Fig. 7] La figure 7 représente une source lumineuse pilotable ;
• [Fig. 8] La figure 8 représente un capteur de luminosité ;
• [Fig. 9] La figure 9 représente un dispositif de pilotage ; et
• [Fig. 10] La figure 10 représente une architecture matérielle d'un ordinateur.

Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate examples of embodiment devoid of any limiting character. In the figures:

• [ Fig. 1 ] There figure 1 represents a lighting control system according to a particular embodiment of the invention;
• [ Fig. 2 ] There figure 2 represents, in flowchart form, steps of a lighting control method according to the invention;
• [ Fig. 3 ] There Figure 3 represents a point in a color space corresponding to HSV format;
• [ Fig. 4 ] There figure 4 illustrates in particular a zone representative of a range of colors preferably associated with a brightness sensor;
• [ Fig. 5 ] There figure 5 illustrates a change in the color of light detected by a brightness sensor;
• [ Fig. 6 ] There Figure 6 illustrates a gradient descent that can be implemented in a particular embodiment;
• [ Fig. 7 ] There Figure 7 represents a controllable light source;
• [ Fig. 8 ] There figure 8 represents a brightness sensor;
• [ Fig. 9 ] There Figure 9 represents a control device; And
• [ Fig. 10 ] There Figure 10 represents a hardware architecture of a computer.

Appendix 1 details a method for converting a color in RGB format, into a color in HSV format.

Appendix 2 details a method for converting a HSV format color into an RGB format color.

Description of embodiments

There figure 1 represents a lighting control system S conforming to a particular mode of implementation of the invention, this system S comprising N _C brightness sensors C ( _NC ≥ 1), N _L controllable light sources L, ( _NL ≥ 1), and at least one control device P. In this example, the system S is placed in a room which includes, in addition to the controllable light sources, a first light source constituted by a window F and a second light source constituted by a television TV.

There figure 2 represents the main steps implemented by the different elements in L, C, P of the system S in a particular embodiment of the invention.

In the embodiment described here, when a controllable light source L is turned on, for example by means of a switch or a remote control, it sends, during a step L10, an activation signal SIG _ON . This SIG _ON activation signal is received by the control device P during a step P10.

In the embodiment described here, when the control device P receives an activation signal SIG _ON coming from a controllable light source L, it sends to this controllable light source L, during a step P20, a comm command ( DEF ) so that it emits light with a default color, for example a white of 6000 K (Kelvins). This command is received by the controllable light source L during a step L20.

In the embodiment described here, during a step C30 implemented iteratively, for example every minute, at least one brightness sensor C captures a light and measures information representative of the color of this light.

In the embodiment described here, the brightness sensors C are RGB sensors configured to measure the red, green and blue components of the light that they detect.

In the embodiment described here, a brightness sensor C sends, during a step C40, an msg message ( r,g,b ) comprising the red, green and blue components of the light detected by this sensor to the device piloting P. This msg message ( r , g , b ) is received by the control device P during a step P40.

In the embodiment described here, the message msg further includes a power W of the light received by the brightness sensor C and if this power is less than a threshold TH, the control device P emits an alarm (step P100) .

In the embodiment described here, when the control device P receives a message comprising red, green and blue components of the color of the light (first format within the meaning of the invention), it converts, during a step P50, these components in another color format (second format within the meaning of the invention).

This conversion is optional. It is particularly advantageous when the second color format allows a spatial representation of the colors more adapted to the implementation of gradient descent than the first color format.

Firstly, the HSV format allows color information and brightness information to be separated: unlike the RGB format, the HSV format allows color information (Hue, Saturation) and color information to be processed independently. brightness (Value).

Thus, exploiting the HSV format to implement gradient descent in a chromaticity plane (i.e. a hue-saturation plane) is particularly suited to controlling the color of a light source. During the gradient descent in such a chromaticity plane (hue-saturation), only the color emitted by the light source will be modified and the brightness remains unchanged.

Furthermore, the HSV format is based on the perception of colors by the human eye: it is directly based on the perception of colors by the human eye, which is not the case with the RGB format.

• la superposition de deux sources lumineuses de couleurs respectives P1 et P2, et
• une unique source lumineuse de couleur correspondant à la moyenne (i.e. le barycentre) de P1 et P2.

Let us assume two colors defined in the HSV format and represented by two points P1 and P2 in a chromaticity plane. In this case, the human eye will perceive the same way:

• the superposition of two light sources of respective colors P1 and P2, and
• a single color light source corresponding to the average (ie the barycenter) of P1 and P2.

Conversely, this property is not respected for two colors defined in the RGB format. The use of the HSV format during a transition between two given colors is adapted to the color perception by the human eye: during such a transition, a user perceives fewer color variations if the HSV format than if the RGB format is used.

In the embodiment described here, the red, green and blue components of the color of the light are converted into components ( h,s,v ) of the HSV format (hue-saturation-value, hue-saturation-luminance in French) according to a method detailed below in Appendix 1.

There Figure 3 represents in the form of a cross, a point in a color space corresponding to the HSV format.

In such a color space, and in a known manner, pure hues are represented on the edge of the space. For the same color tone, the saturation (representing the distance from white) is lower as we get closer to the outside of the space.

When the lighting control system S includes several brightness sensors L , the control device P potentially receives from each of these sensors a message comprising the red, green and blue components of the color of the light captured by this sensor. It obtains, by conversion, the components of each of these colors in HSV format.

In the embodiment described here, during a step P60, the control device P checks whether the color of the light captured by a brightness sensor C is in a range P _COL of colors preferably associated with this sensor C .

For this purpose, in the embodiment described here, the control device P includes a database BD _P in which a range of preferred colors is associated with each brightness sensor C.

In one embodiment, the preferred color range associated with a sensor may be a function of variable parameters, for example the time, the time of year, a user detected near the sensor, a context of use (domestic application, workspace, etc.).

• un point L1 représentant la couleur de la lumière émise par la source lumineuse pilotable L1 ;
• un point L2 représentant la couleur de la lumière émise par la source lumineuse pilotable L2 ;
• un point C1 représentant la couleur de la lumière détectée par le capteur de luminosité C1 ; et
• une zone Z représentative de la plage P_COL de couleurs de préférence associée au capteur de luminosité C1.

There figure 4 illustrates, in a color space corresponding to the HSV format, for a system S comprising a brightness sensor C1 and two controllable light sources L1 and L2:

• a point L1 representing the color of the light emitted by the controllable light source L1;
• a point L2 representing the color of the light emitted by the controllable light source L2;
• a point C1 representing the color of the light detected by the brightness sensor C1; And
• a zone Z representative of the color range P _COL preferably associated with the brightness sensor C1.

In the example of the figure 4 , the color of the light detected by the brightness sensor C1 is not included in the range of colors preferably associated with the brightness sensor C1, so that the test result of step P60 is negative.

In one embodiment of the invention, during the test P60, the control device P does not consider the color of the light captured instantly by a brightness sensor but averages the color of the light captured over a period of time .

In the embodiment described here, when the control device P determines that the color of the light detected by at least one brightness sensor C is not included in the range of colors preferably associated with this brightness sensor C ( result of the test of step P60 negative), during a step P70 detailed below, the control device P sends at least one comm command ( r _Q , g _Q , b _Q ) to at least one light source controllable L to modify the color emitted by this light source so that the light detected by this brightness sensor ( C ) is included in or approaches the range of colors preferably associated with this brightness sensor ( C ).

Based on the example of the figure 4 , there figure 5 illustrates the changes in the colors emitted by the controllable light sources L1 and L2, the impact on the color of the light detected by the brightness sensor C1, and the fact that this color is then included in the P _COL range of preferred colors associated with the C1 light sensor. Under these conditions, the test result of step P60 is positive.

In reference to the Figure 6 , we detail below a gradient descent making it possible to implement step P70 mentioned above, in one embodiment. This gradient descent makes it possible to gradually change the lighting of a controllable light source so that brightness sensors (two in the example below) detect light whose color corresponds to the preferred color ranges associated with this sensor. .

• r_S ,g_S ,b_S les composantes rouge, verte et bleue de la lumière émise par la source lumineuse et h_S ,s_S ,v_S les composantes HSV de cette lumière (obtenues par conversion selon l'Annexe 1)
• r1 _M ,g1 _M ,b1 _M les composantes rouge, verte et bleue de la lumière (mesurée) captée par le capteur C1 et h1 _M ,s1 _M ,v1 _M les composantes HSV de cette lumière (obtenues par conversion selon l'Annexe 1) ;
• h1 _T ,s1 _T ,v1 _T les composantes HSV d'une lumière de la plage de préférence associée au capteur C1 (par exemple le barycentre de cette plage) et r1 _T ,g1 _T ,b1 _T les composantes rouge, verte et bleue de cette lumière (obtenues par conversion selon la méthode exposée à l'Annexe 2) ;
• r2_M ,g2 _M ,b2 _M les composantes rouge, verte et bleue de la lumière (mesurée) captée par le capteur C2 et h2 _M ,s2 _M ,v2 _M les composantes HSV de cette lumière (obtenues par conversion selon l'Annexe 1) ;
• h2 _T ,s2 _T ,v2 _T les composantes HSV d'une lumière de la plage de préférence associée au capteur C2 (par exemple le barycentre de cette plage) et r2 _T ,g2 _T ,b2 _T les composantes rouge, verte et bleue de cette lumière (obtenues par conversion selon la méthode exposée à l'Annexe 2).

We note, using the notations in Appendices 1 and 2:

• r _S , g _S , b _S the red, green and blue components of the light emitted by the light source and h _S , s _S , v _S the HSV components of this light (obtained by conversion according to Annex 1)
• r 1 _M , g 1 _M , b 1 _M the red, green and blue components of the light (measured) captured by the sensor C1 and h 1 _M , s 1 _M , v 1 _M the HSV components of this light (obtained by conversion according to Annex 1);
• h 1 _T , s 1 _T , v1 _T the HSV components of a light in the range preferably associated with the sensor C1 (for example the barycenter of this range) and r 1 _T , g 1 _T , b 1 _T the red components , green and blue of this light (obtained by conversion according to the method set out in Appendix 2);
• r2 _M , g 2 _M , b 2 _M the red, green and blue components of the light (measured) captured by the sensor C2 and h 2 _M , s 2 _M , v 2 _M the HSV components of this light (obtained by conversion according to Annex 1);
• h 2 _T , s 2 _T , v 2 _T the HSV components of a light of the range preferably associated with the sensor C2 (for example the barycenter of this range) and r 2 _T , g 2 _T , b 2 _T the components red, green and blue of this light (obtained by conversion according to the method set out in Appendix 2).

During a substep P71, the control device P calculates for each sensor CX the vector VX = ( hX _T - hX _M , sX _T - sX _M , vX _T - vX _M ) .

During a substep P72, the control device P sums the vectors VX to obtain a single vector Z. In this example, with two sensors C1 and C2: $$Z=V1+V2=\left(h{1}_T+h{2}_T-h{1}_M-h{2}_M,s{1}_T+s{2}_T-s{1}_M-s{2}_M,v{1}_T+v{2}_T-v{1}_M-v{2}_T\right)$$

During a substep P73, the control device P determines whether the norm of the vector Z is less than a threshold ε, below which it is considered that the algorithm has converged towards a local minimum.

If the norm of the vector Z is greater than or equal to the threshold ε, during a sub-step P74, the control device P calculates a point Q = ( h _Q , s _Q , v _Q ) = ( µ.Z + ( h _S , s _S , v _S )) obtained by displacement according to the sense and direction of the vector Z from the point ( h _s , s _s , v _s ) corresponding to the emission of the light source where µ is a parameter control of the evolution speed between 0 and 1.

Those skilled in the art will understand that the convergence of the algorithm cannot be guaranteed given that the level of impact of the light emitted by a light source on the values captured by the sensors is not known a priori, and that the environment other than controllable light sources also has an impact (natural lighting, etc.). Furthermore, when multiple sensors are used, it may be physically impossible to satisfy them all at the same time, even with multiple sources. On the other hand, for values of µ, we can guarantee that this algorithm does not diverge and we will therefore remain “around” the preferred color ranges, without necessarily being able to reach them to within ε.

In one embodiment of the invention, the controllable light sources ( L ) are configured to be controlled by commands comprising color parameters in RGB format and during a sub-step P75, the control device P converts, according to the method set out in Appendix 2, the HSV coordinates of this point Q in red, green and blue coordinates ( r _Q , g _Q , b _Q )

During a sub-step, P76, the control device P sends a comm command ( r _Q , g _Q , b _Q ) to the controllable light source so that it emits light with these red, green and blue.

In another embodiment of the invention, the controllable light sources ( L ) are configured to be controlled by commands comprising color parameters in HSV format. Conversion step P75 is not executed and during step P70, the control device sends to the controllable light source ( L ), a comm command ( h _Q , s _Q , v _Q ) whose parameters are the components of the color corresponding to the point ( Q ) in HSV format as determined in step P74.

The comm command is received by the light source during a step L70 and the light source emits a color according to the parameters of this command. The light then captured by the brightness sensors is then included in or approximates the color ranges preferably associated with these sensors.

1. 1/ A la sous-étape P72, le dispositif de pilotage somme les vecteurs CX pour obtenir un vecteur unique Z pondéré par des poids wY respectivement associés aux sources SY, tous initialisés à 1.
   Dans notre exemple : $$Z=\left(\begin{array}{l}w1.\left(h{1}_T-h{1}_M\right)+w2.\left(h{2}_T-h{2}_M\right),w1.\left(s{1}_T-s{1}_M\right)+w2.\left(s{2}_T-s{2}_M\right),w1.\left(v{1}_T-v{1}_M\right)\\ +w2.\left(v{2}_T-v{2}_M\right)\end{array}\right)$$
   
2. 2/ Au cours de la sous-étape P74, pour chaque source SY, le dispositif de pilotage P calcule un point QY = (h_QY ,s_QY ,v_QY ) = (µ.Z + (h_SY,s_SY,v_SY )) obtenu par déplacement selon le sens et la direction du vecteur Z depuis le point (h_SY ,s _SY ,v_SY ) correspondant à l'émission de la source lumineuse SY où µ est un paramètre de contrôle de la vitesse d'évolution compris entre 0 et 1.
3. 3/ Au cours de la sous-étape P75, le dispositif de pilotage P convertit, pour chaque source SY, les coordonnées HSV du point QY en coordonnées rouge, verte et bleue (r_QY, g_QY, b_QY )
4. 4/ Au cours de la sous-étape P76, le dispositif de pilotage P envoie, à chaque source SY, une commande comm(r_QY , g_QY,b_QY ) pour que celle-ci émette une lumière avec ces composantes rouge, verte et bleue.
5. 5/ Le dispositif de pilotage détermine, pour chaque capteur CX, la différence WX entre la couleur mesurée par ce capteur avant et après pilotage des sources LY. Il ajuste le poids wY associé à chaque source SY à partir de ces différences WX et d'une fonction prédéfinie f.

When the system includes several light sources SY (for example two sources S1, S2):

1. 1/ In substep P72, the control device sums the vectors CX to obtain a single vector Z weighted by weights wY respectively associated with the sources SY, all initialized to 1.
   In our example: $$Z=\left(\begin{array}{l}w1.\left(h{1}_T-h{1}_M\right)+w2.\left(h{2}_T-h{2}_M\right),w1.\left(s{1}_T-s{1}_M\right)+w2.\left(s{2}_T-s{2}_M\right),w1.\left(v{1}_T-v{1}_M\right)\\ +w2.\left(v{2}_T-v{2}_M\right)\end{array}\right)$$
   
2. 2/ During substep P74, for each source SY, the control device P calculates a point QY = ( h _QY , s _QY , v _QY ) = (µ. Z + ( h _SY ,s _SY ,v _SY )) obtained by displacement in the direction and direction of the vector Z from the point ( h _SY , s _SY , v _SY ) corresponding to the emission of the light source SY where µ is a parameter for controlling the speed of evolution between 0 and 1.
3. 3/ During substep P75, the control device P converts, for each source SY, the HSV coordinates of the point QY into red, green and blue coordinates ( r _QY , g _QY , b _QY )
4. 4/ During substep P76, the control device P sends, to each source SY, a comm command ( r _QY , g _QY , b _QY ) so that it emits light with these red, green components and blue.
5. 5/ The control device determines, for each CX sensor, the difference WX between the color measured by this sensor before and after control of the LY sources. It adjusts the weight wY associated with each source SY from these differences WX and a predefined function f.

For example, the function f can be defined by: wY' = wY + tanh ( WX ), where wY' represents the adjusted weight, and tanh the hyperbolic tangent function, or other similar sigmoid function making it possible to bound the evolution factor of the weight (for example at +1/-1 max with tanh). Limiting the weight change factor to a precise interval makes it possible to avoid discrepancies in values.

There Figure 7 represents a controllable light source L. It includes in particular a communication module COM _L and a controller CTR _L. This controller is configured to implement steps L10 to L70 described with reference to the figure 2 . The source in particular receives commands from the control device via its communication means and the controller modifies the color of the light emitted by the source based on the parameters of this command.

There figure 8 represents a brightness sensor C. It includes a COM _C communication module, a CTR _C controller and a CAP light color sensor itself. This controller is configured to implement steps C10 to C40 described with reference to the figure 2 . In particular, the CAP sensor is configured to deliver to the CRT _P controller the color of the light that it receives at a given instant, for example the red, green and blue components of the light. The CTR _P controller controls the COM _P communication module so that it sends the color components to the P control device.

• un module de communication COM_P,
• un contrôleur CTR_P,
• un module de conversion CONV configuré pour convertir des composantes RGB en composantes HSV, et inversement,
• et une base de données BD_P qui associe une plage de couleurs de préférence à chaque capteur de luminosité C.

There Figure 9 represents a control device P. It comprises:

• a COM _P communication module,
• a CTR _P controller,
• a CONV conversion module configured to convert RGB components into HSV components, and vice versa,
• and a database BD _P which associates a range of colors preferably with each brightness sensor C.

The CTR _P controller is configured to implement steps P10 to P70 described with reference to the figure 2 . In particular, this controller determines, by gradient descent, the commands to be sent to the light sources so that the colors of the lights detected by the sensors correspond to or approach the preference ranges associated with these sensors.

The COM _C , COM _L , COM _P communication modules are configured to allow the brightness sensors, the controllable light sources and the control device to communicate with each other, for example using the Bluetooth or Wifi protocol.

A controllable light source L , a brightness sensor C and a control device P can have the hardware architecture of a computer represented in Figure 10 and may in particular include a processor 10, a read only memory 11, a RAM 12 and a rewritable non-volatile memory 13.

For a brightness sensor C , the read only memory 11 can constitute a recording medium conforming to an embodiment of the invention, readable by the processor 10, and on which is recorded a computer program PROG _L configured to implement implements steps C10 to C40 described with reference to the figure 2 when executed by processor 10.

For the controllable light source L , the read only memory 11 can constitute a recording medium conforming to an embodiment of the invention, readable by the processor 10, and on which is recorded a computer program PROG _L configured to implement implements steps L10 to L70 described with reference to the figure 2 when executed by processor 10.

For a control device P , the read only memory 11 can constitute a recording medium conforming to an embodiment of the invention, readable by the processor 10, and on which is recorded a computer program PROG _P configured to implement implements steps P10 to P70 described with reference to the figure 2 when executed by the processor 10. The rewritable non-volatile memory 13 may include the database BD _C.

Annex 1

This appendix describes how to convert a color point represented by its components R (red), G (green) and B (blue) into HSV (hue-saturation-value, hue-saturation-luminance in French).

$$h\in \left[\mathrm{0,360}\right[$$

$$\max =\max \left(r,g,b\right),\min =\min \left(r,g,b\right)$$

$$h=\{\begin{array}{c}0\mathit{si}\max =\mathit{min}\\ \left(60°\times \frac{g-b}{\max -\mathit{min}}+360°\right)\mathit{mod}360°\mathit{si}\max =r\\ \left(60°\times \frac{b-r}{\max -\mathit{min}}+120°\right)\mathit{si}\max =g\\ \left(60°\times \frac{r-g}{\max -\mathit{min}}+240°\right)\mathit{si}\max =b\end{array}$$

$$s=\{\begin{array}{c}0\mathit{si}\max =0\\ 1-\frac{\mathit{min}}{\max }\mathit{sinon}\end{array}$$

$$v=\mathit{max}$$

We assume here that each of the components R, G, B is an integer in {0, ..., 255}; in the following formulas, we use RGB values between 0 and 1 (by dividing each of the components by 255). $$r,g,b,s,v\in \left[0.1\right]$$

$$h\in \left[0.360\right[$$

$$\max =\max \left(r,g,b\right),\min =\min \left(r,g,b\right)$$

$$h=\{\begin{array}{c}0\mathit{if}\max =\mathit{min}\\ \left(60°\times \frac{g-b}{\max -\mathit{min}}+360°\right)\mathit{mod}360°\mathit{if}\max =r\\ \left(60°\times \frac{b-r}{\max -\mathit{min}}+120°\right)\mathit{if}\max =g\\ \left(60°\times \frac{r-g}{\max -\mathit{min}}+240°\right)\mathit{if}\max =b\end{array}$$

$$s=\{\begin{array}{c}0\mathit{if}\max =0\\ 1-\frac{\mathit{min}}{\max }\mathit{Otherwise}\end{array}$$

$$v=\mathit{max}$$

Appendix 2

$$h\in \left[\mathrm{0,360}\right[$$

$$h_i=\lfloor \frac{h}{60}\rfloor \mathit{mod}6$$

$$f=\frac{h}{60}-h_i$$

$$l=v\times \left(1-s\right)$$

$$m=v\times \left(1-f\times s\right)$$

$$n=v\times \left(1-\left(1-f\right)\times s\right)$$

$$\left(r,g,b\right)=\{\begin{array}{c}\left(v,n,l\right)\mathit{si}{h}_i=0\\ \left(m,v,l\right)\mathit{si}{h}_i=1\\ \left(l,v,n\right)\mathit{si}{h}_i=2\\ \left(l,m,v\right)\mathit{si}{h}_i=3\\ \left(n,l,v\right)\mathit{si}{h}_i=4\\ \left(v,l,m\right)\mathit{si}{h}_i=5\end{array}$$

This appendix describes how to convert a color point defined by its HSV components (hue-saturation-value, hue-saturation-luminance in French) into R (red), G (green) and B (blue) components. $$r,g,b,s,v\in \left[0.1\right]$$

$$h\in \left[0.360\right[$$

$$h_i=\lfloor \frac{h}{60}\rfloor \mathit{mod}6$$

$$f=\frac{h}{60}-h_i$$

$$L=v\times \left(1-s\right)$$

$$m=v\times \left(1-f\times s\right)$$

$$\mathrm{not}=v\times \left(1-\left(1-f\right)\times s\right)$$

$$\left(r,g,b\right)=\{\begin{array}{c}\left(v,\mathrm{not},L\right)\mathit{if}{h}_i=0\\ \left(m,v,L\right)\mathit{if}{h}_i=1\\ \left(L,v,\mathrm{not}\right)\mathit{if}{h}_i=2\\ \left(L,m,v\right)\mathit{if}{h}_i=3\\ \left(\mathrm{not},L,v\right)\mathit{if}{h}_i=4\\ \left(v,L,m\right)\mathit{if}{h}_i=5\end{array}$$

Claims (11)

Method for controlling at least one controllable light source ( L ) implemented by a control device ( P ), said method comprising steps of: - reception (P40), from at least one brightness sensor ( C ), of a message ( msg ) comprising information ( r,g,b ) representative of a color of light captured by said at minus one sensor; - verification (P60) if the color of the light captured by said at least one brightness sensor ( C ) is in a range ( P _COL ) of colors preferably associated with said at least one sensor ( C ); and when this is not the case: - sending (P70) to at least one controllable light source ( L ), at least one control command ( comm ( r _Q , g _Q , b _Q )) comprising parameters ( r _Q , g _Q , b _Q ) of color to modify a color emitted by said at least one light source according to said parameters ( r _Q , g _Q , b _Q ) so that the light detected by said at least one brightness sensor ( C ) is included or is approximates the preferred color range associated with this brightness sensor ( C ). Control method according to claim 1 in which said verification (P60) takes into account an average of the color of the light captured by said at least brightness sensor (C) over a period of time. Control method according to claim 1 or 2 in which said parameters ( r _Q , g _Q , b _Q ) of said control command ( comm ) are determined (P75) by a gradient descent. Control method according to any one of claims 1 to 3, in which said received information (P40) representative of the color captured by said at least one brightness sensor (C) is in a first format, said method comprising in one step (P50) for converting said information into a second color format, said gradient descent being implemented in a color space conforming to this second color format. Control method according to claim 4 in which said information representative of a color captured by said at least one brightness sensor is in RGB format and converted (P50) to HSV format. Control method according to any one of claims 1 to 5 comprising; upon reception (P10) of an activation signal coming from said light source controllable ( L ), sending (P20) to this controllable light source ( L ) a control command ( eomm ( DEF )) so that it emits light with a default color. Control method according to any one of claims 1 to 6 further comprising a step (P100) of emitting an alarm if a power ( W ) of the light received by said at least one sensor is less than a threshold ( TH ) . Control device ( P ) comprising: - a communication module ( COM _P ) configured to receive, from at least one brightness sensor ( C ), a message ( msg ) comprising information ( r,g,b ) representative of a color of a light captured by said at least one sensor; - a controller ( CTR _P ) configured to check whether the color of the light captured by said at least one brightness sensor ( C ) is in a range ( P _COL ) of colors preferably associated with said at least one sensor ( C ); and when this is not the case to control said communication module ( COM _P ) so that it sends (P70) to at least one controllable light source ( L ), at least one control command ( comm ( r _Q , g _Q ,b _Q )) comprising color parameters ( r _Q ,g _Q ,b _Q ) for modifying a color emitted by said at least one light source according to said parameters ( r _Q ,g _Q ,b _Q ) so as to that the light detected by said at least one brightness sensor ( C ) is included in or approaches the range of colors preferably associated with this brightness sensor ( C ). Lighting control system ( S ) comprising at least one control device ( P ) according to claim 8, at least one brightness sensor ( C ) and at least one controllable light source ( L ). Computer program ( PG _P ) comprising instructions for executing the steps of the control method according to any one of claims 1 to 7 when said program is executed by a computer. Computer-readable recording medium on which a computer program ( PG _P ) is recorded comprising instructions for executing the steps of the control method according to any one of claims 1 to 7.

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