method for controlling an optical head intended for use in an individual observation system

Abstract

The invention relates to a method for controlling (100) an optical head intended for use in a system for observing an individual located inside a vehicle's passenger compartment, said method (100) using a control unit arranged to supply said optical head with a power supply current, said method (100) comprising at least one iteration of the following steps: - measurement (102), by the control unit, of at least one characteristic of the power supply current; - analysis (104), by the control unit, of at least one characteristic by comparing at least one characteristic to a limit value; - shutdown (106), by the control unit, of the power supply current to the optical head when at least one characteristic exceeds the limit value. Figure for the abstract: Fig. 1

Description

Title of the invention: method for controlling an optical head intended to be used in a system for observing an individual Technical field of the invention

[0001] The present invention relates to a method for controlling an optical head intended to be used in a system for observing an individual located inside a vehicle passenger compartment.

[0002] It also relates to a control unit of an optical head and a control system. State of the art

[0003] Methods are known for controlling an optical head used to observe an individual in the passenger compartment of a vehicle. These methods are functional but pose various problems, in particular: - ease of implementation because these techniques can be based on image processing techniques which use algorithms to measure elements of interest; - time, linked to the problem of ease of implementation, because the processes often carry out operations which are very costly in terms of calculation time; - costs because the components used to carry out these operations can be specific and difficult to implement; - efficiency because the steps of these control processes are carried out by separate elements. The steps are therefore not centralized, which leads to a loss of implementation time and difficulty in implementation. Presentation of the invention

[0004] In this context, the present invention provides a method for controlling an optical head intended to be used in a system for observing an individual located inside a passenger compartment of a vehicle, said method using a control unit arranged to power said optical head with a supply current, said method comprising at least one iteration of the following steps: - measurement, by the control unit, of at least one characteristic of the supply current, preferably said characteristic relating to a duration of application of the supply current or to a duration during which the supply current is greater than a minimum value or to an intensity of the supply current; - analysis, by the control unit, of the at least one characteristic by comparison of the at least one characteristic with a limit value; - stopping, by the control unit, of a supply of the power supply current to the optical head when at least one characteristic is greater than the limit value.

[0005] Thus, according to the method according to the invention, the control of the optical head is directly based on a measurement and a comparison of the supply signal with a limit value. No other analysis technique is used, for example, no image processing is used for the control (of the illumination) of the optical head. The method is therefore very simple to implement, easy to implement and inexpensive in terms of computing time.

[0006] Furthermore, all the steps of the method are implemented by a single element, the control unit. The steps of the method according to the invention are therefore managed centrally, which allows the method to be more efficient, faster and more secure. Furthermore, since the optical head does not perform any control action, standard optical heads can be used, which limits the costs of these components.

[0007] According to one embodiment, the at least one characteristic relates to an application duration and the limit value is a first threshold, the stopping step being configured to be triggered when the at least one characteristic is greater than the first threshold.

[0008] Advantageously, the first threshold is less than or equal to 6 milliseconds.

[0009] In another embodiment, an additional characteristic, relating to an intensity of the supply current, is measured in the measuring step, the stopping step being configured to be triggered as soon as the at least one characteristic reaches the first threshold or as soon as the additional characteristic is greater than a second threshold.

[0010] Advantageously, the second threshold is less than or equal to 10 amps.

[0011] According to another embodiment, the at least one characteristic relates to an intensity of the supply current and the limit value is a second threshold, the stopping step being configured to trigger when the at least one characteristic is greater than the second threshold.

[0012] Advantageously, the second threshold is less than or equal to 10 amps.

[0013] In another embodiment, said vehicle comprises a starting system, said method comprising, prior to the measuring step, a step of engaging said optical head each time said starting system is powered up.

[0014] Advantageously, the method is repeated each time the starting system is powered up.

[0015] Preferably, the method comprises an additional stopping step each time the starting system of said vehicle is switched off.

[0016] The invention also proposes a control unit for an optical head intended to be used in a system for observing an individual located inside a vehicle passenger compartment, said control unit comprising: - a measuring module arranged to measure at least one characteristic of a supply current of said optical head, preferably said at least one characteristic relating to a duration of application of the supply current or to a duration during which the supply current is greater than a minimum value or to an intensity of the supply current; - an analysis module arranged to analyze the at least one characteristic by comparing the at least one characteristic to a limit value; - an on / off module arranged to stop a supply of the power supply current to the optical head when the at least one characteristic is greater than said limit value.

[0017] The control unit according to the invention thus makes it possible to centrally manage the control of the optical head. The control unit therefore has advantages similar to those developed for the method according to the invention.

[0018] Furthermore, according to this solution, the control module is no longer positioned in the optical head, which makes it possible to considerably reduce the volume of the optical head. As a result, the optical head is more easily integrated into vehicles and adaptable to the vehicle's usage and layout requirements.

[0019] Then, the different modules of the control unit carry out operations that are simple to implement. As a result, the control unit uses few components and these components are standard components. The arrangement of the control unit is also easier to implement.

[0020] In one embodiment, the on / off module comprises a switch comprising two operating states, a closed state and an open state, said switch being arranged to switch to the open state after receiving a stop command from the analysis module to stop the supply of the power supply current to the optical head.

[0021] In another embodiment, the vehicle comprises a starting system, the start / stop module being arranged to start the supply of the power supply current to the optical head each time said starting system is switched on and to stop the supply of the power supply current each time said starting system is switched off.

[0022] In another embodiment, the measurement module comprises a conversion module configured to convert said supply current into an electrical voltage and a digitization module configured to digitize said electrical voltage, said digitized electrical voltage being transmitted to the analysis module.

[0023] According to another aspect of the invention, there is provided a control system comprising: - an optical head comprising a light source, preferably pulsed; - a control unit for said optical head according to the invention.

[0024] The system according to the invention is therefore more compact than the systems of the state of the art because the modules participating in the control of the optical head are all positioned at the level of the control unit (computing unit) of the system. Thus, the optical head is very compact and can be modulated to the needs of the individual and the vehicle. In addition, a standard optical head can be used in the system according to the invention, which limits the costs for this component.

[0025] The system is also easy to implement, because the operations performed by the various components are easy to arrange and use standard components.

[0026] According to one embodiment, the light source is a pulsed source.

[0027] Preferably, the light source is an infrared source.

[0028] In another embodiment, the optical head comprises a sensor arranged to acquire at least one image of said individual when said individual is illuminated by said light source.

[0029] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. Detailed description of the invention

[0030] The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented. The invention is not limited to the embodiments illustrated in the drawings. Consequently, it should be understood that, when the characteristics mentioned in the claims are followed by reference signs, these signs are included solely for the purpose of improving the intelligibility of the claims and in no way limit the scope of the claims.

[0031] In the attached drawings:

[0032] [Fig. 1] is a schematic representation of a first embodiment of a method according to the invention;

[0033] [Fig.2] is a schematic representation of a second embodiment of a method according to the invention when a starting system of a vehicle is powered up;

[0034] [Fig.3] is a schematic representation of the second embodiment of the method according to the invention when the starting system of a vehicle is switched off;

[0035] [Fig.4] is a schematic representation of a new iteration of the second embodiment of the method according to the invention when the starting system of a vehicle is powered up again;

[0036] [Fig.5] is a schematic representation of a first embodiment of a control unit according to the invention;

[0037] [Fig.6] is a schematic representation of a second embodiment of a control unit according to the invention;

[0038] [Fig.7] is a schematic representation of a system according to the invention;

[0039] [Fig.8] is a schematic representation of a power signal measured by a measuring unit belonging to a control unit according to the invention;

[0040] [Fig.9] is a schematic representation of an example of a light signal emitted by a light source of an optical head belonging to a system according to the invention.

[0041] [Fig. 1] illustrates a first example of embodiment of a method according to the present disclosure.

[0042] In particular, [Fig.l] illustrates a method 100 for controlling an optical head intended to be used in a system for observing an individual located inside a vehicle passenger compartment. The method 100 uses a control unit arranged to power the optical head with a supply current.

[0043] By supply current is meant a current necessary for the operation of the optical head. This supply current is preferably supplied to the optical head to power it in order to operate said optical head. Since the supply current relates to an electrical signal, the supply current can be defined by parameters defining the signal of the supply current. These parameters can relate to a time, an intensity. In this example, the optical head comprises a light source arranged to illuminate the individual. The supply current therefore also serves to power the light source of the optical head.

[0044] The method 100 comprises a step 102 of measuring, by the control unit, at least one characteristic of the supply current.

[0045] By characteristic is meant a parameter of the supply current. For example, the characteristic of the supply current may relate to a duration of application of the supply current or to a duration during which the supply current is greater than a minimum value and / or to an intensity of the supply current. The minimum value may relate to a residual supply current. For example, the minimum value may be 0.5 amperes. Thus, the duration of application of the supply current may be proportional to the duration during which the individual is illuminated by the optical head. For example, the duration of application of the current corresponds to a pulse duration of the light source of the optical head. or to a duration during which the individual is illuminated by the optical head. In this case, the signal representing the supply current is not zero and is preferably in the form of a square wave at a high state. The intensity of the supply current is preferably proportional to the light intensity emitted by the optical head, preferably by the light source of the optical head. Thus, the higher the intensity of the supply current, the higher the light emission power of the optical head, preferably the light source of the optical head. The light signal emitted by the optical head is therefore higher. In another embodiment, the at least one characteristic relates to a light power.

[0046] The method 100 further comprises a step 104 of analysis, by the control unit, of the at least one characteristic by comparing the at least one characteristic to a limit value. Thus, at least one characteristic of the supply current is extracted in order to be compared to the limit value.

[0047] The method 100 then comprises a step 106 of stopping, by the control unit, a supply of the supply current to the optical head when the at least one characteristic is greater than the limit value. Thus, if the at least one characteristic is greater than the limit value, then the supply of the optical head is stopped. No supply current is supplied to the optical head. Otherwise, the supply of the optical head is maintained. For example, the stopping of the supply of the supply current to the optical head is initiated by the control unit which issues a stop command to stop the supply of the optical head.

[0048] The method 100 thus describes a method for controlling the optical head making it possible to control the operation of the optical head in order to guarantee safety conditions for the individual observed by the optical head. Indeed, according to the method according to the invention, the stopping or continuity of the power supply to the optical head is based on a comparison of at least one parameter of the power supply current with the limit value. No expensive computational technique, for example image processing techniques, is used by the method 100. The method 100 is therefore easy to implement.

[0049] In a first embodiment, the measuring step 102 is configured to measure the characteristic relating to the duration of application of the supply current or a duration during which the supply current is greater than a minimum value of the supply current. According to this exemplary embodiment, the limit value is associated with a first threshold. Thus, when the characteristic relating to the chosen duration reaches the first threshold, for example becomes greater than the first threshold, then the stopping step 106 is triggered. The supply of the optical head by the control unit is thus stopped.

[0050] Such a feature makes it possible to limit the quantity of radiation emitted by the optical head, for example infrared radiation, in particular in the event of the presence of an individual nearby. With the method 100, prolonged illumination of the individual by the optical head is limited, which makes it possible to ensure the comfort of the individual and also to ensure a level of protection from the light rays. For example, the first threshold can be chosen in a range between 0.1 milliseconds (ms) and 6 milliseconds. Preferably, the first threshold is set at 6 milliseconds. Such a threshold makes it possible to guarantee both a better level of comfort, for example visual comfort, and also a better level of safety, for example a high level of visual safety. Comfort and safety are therefore improved.

[0051] In a second embodiment, the measuring step 102 is configured to measure the characteristic relating to an intensity of the supply current. According to this exemplary embodiment, the limit value is associated with a second threshold. Thus, when the characteristic relating to the supply current reaches the second threshold, then the stopping step 106 is triggered. The supply of the optical head by the control unit is stopped.

[0052] Such a configuration makes it possible to imitate the light intensity emitted by the optical head and which can be received by the individual, for example infrared radiation. For example, the second threshold can be chosen in a range between 0.1 milliampere (mA) and 10 amperes (A). Preferably, the second threshold is set at 10 amperes. Such a threshold makes it possible to guarantee better comfort and also better safety.

[0053] In a third embodiment, the measuring step 102 is configured to measure the at least one characteristic relating to the duration of application of the supply current or a duration during which the supply current is greater than a minimum value of the supply current and an additional characteristic relating to the intensity of the supply current. Thus, in this embodiment, two characteristics of the supply current are measured, preferably simultaneously, by the control unit. The two parameters are the duration of application of the supply current or duration during which the supply current is greater than a minimum value of the supply current as well as the intensity of the supply current.In this embodiment, the additional characteristic is compared to the second threshold (threshold identical to the second embodiment) while the characteristic relating to the duration is compared to the first threshold (threshold identical to the first embodiment). In this embodiment, the stopping step 106 is triggered when one of the two characteristics measured in the measuring step 102 reaches its respective threshold, i.e. as soon as the first threshold or the second threshold is reached.

[0054] Thus, according to this example, as soon as one of the characteristics reaches its threshold, the power supply to the optical head is stopped. Such a characteristic makes it possible to further improve the safety and comfort of the individual because two parameters are measured simultaneously. As soon as one of the stopping conditions is achieved, the control unit stops powering the optical head with the power supply current.

[0055] In one embodiment of the method 100, the steps of measurement 102, analysis 104 and stopping 106 can be repeated several times. Thus, it is possible to restart the method 100.

[0056] Of course, although only one individual is mentioned in the method 100, the method 100 is also a method of controlling an optical head intended to be used in a system for observing several individuals located inside a passenger compartment of a vehicle.

[0057] Figures 2, 3, 4 illustrate a second example of a method 200 according to the present disclosure.

[0058] The method 200 comprises all the steps of the method 100, thus only the differences with the method 100 illustrated in [Fig.l] will be described.

[0059] The method 200 further comprises a switching-on step 202 carried out before the measurement step 102. The switching-on step 202 makes it possible to activate the optical head. The optical head is thus powered. The switching-on step 202 is activated each time the starting system is switched on. In the method 200, switching on is noted ON-O while switching off is noted OFF-0. Switching on ON-0 may, for example, correspond to switching on the vehicle battery by switching on the key in the vehicle's dashboard.

[0060] By starting system is meant the system which is activated by the activation means of the vehicle, such as a key or a vehicle activation button. Activation corresponds to switching on the starting system. Conversely, deactivation corresponds to switching off the starting system, for example by removing the vehicle key from the dashboard. The starting system comprises at least one battery which is arranged to power the various systems of the vehicle, for example a traction or propulsion system, the air conditioning system, etc. Thus, the starting system is arranged to activate or deactivate the vehicle, in particular the various systems which belong to said vehicle.

[0061] For example, switching on the starting system corresponds to powering the vehicle battery, for example by activating the vehicle key in the dashboard. Powering the battery thus causes power to be supplied to the control unit and therefore the power supply to the optical head to be switched on.

[0062] Of course, the present method 100 can be implemented on different types of vehicles, whether they are thermal, hybrid, electric or operating on hydrogen.

[0063] In [Fig.2], when the vehicle starting system is powered, the method 200 begins a first iteration, noted ni, of the method 200.

[0064] In the example of [Fig. 3], the start system is powered down, for example, by disabling the start system activation key or button. In this case, the method 200 includes an additional shutdown step 204 that automatically shuts down the power supply to the optical head. For example, turning off the start system cuts off a power supply to the control unit, which automatically cuts off the power supply to the optical head.

[0065] In the example of [Fig.4], the starting system is powered again, there is a power-up of the starting system, which makes it possible to power the control unit. The method 200 begins a new iteration, noted n2, of the method 200 illustrated in [Fig.4].

[0066] In an embodiment of the method 200 illustrated in [Fig.4], the stopping of the optical head may have been caused by the performance of the stopping step 106. Thus, a “resetting” or “activation” of the starting system, for example the vehicle battery, makes it possible to start a new iteration of the method 200 after a cutoff of the power supply to the optical head by the stopping step.

[0067] In another embodiment of the method 200 illustrated in [Fig. 4], the stopping of the optical head may have been caused by the stopping of the vehicle or the stopping of the vehicle's power supply. Thus, a "rearming" or "restarting or starting" of the starting system, for example by a power supply from the battery or when starting the starting system, makes it possible to start a new iteration of the method 200 after a cutoff of the power supply to the optical head by the additional stopping step 204.

[0068] Thus, the steps of the method 200 can be carried out after different types of stopping of the power supply to the optical head. The activation of the method 200 is therefore easy to implement and inexpensive because it is linked to common actions, for example via an activation of the vehicle key in the vehicle dashboard.

[0069] Figures 5, 6 each illustrate an exemplary embodiment of a control unit 10 according to the present disclosure. For the sake of clarity, the optical head is illustrated in [Fig.5] by the reference 20 but it should be noted that the optical head 20 is not part of the control unit 10.

[0070] The control unit 10 of [Fig.5] comprises a measurement module 11, an analysis module 12, an on / off module 13.

[0071] In the example illustrated in [Fig.5], the control unit 10 is arranged to implement all the steps of the method 100 or 200.

[0072] According to this example, the control unit 10 can be a computing unit, a micro controller, a controller, a computer, or any other electronic device configured to carry out instructions.

[0073] The measuring module 11 is arranged to measure at least one characteristic of the supply current 40 of the optical head 20. The measuring module 11 can be any sensor or measuring circuit which is arranged to measure an electric current.

[0074] The analysis module 12 is arranged to analyze the at least one characteristic of the supply current 40 by comparing the at least one characteristic to a limit value. For example, the analysis module 12 may be a processor of the control unit 10, for example a microprocessor.

[0075] The on / off module 13 is arranged to stop a supply of the supply current 40 to the optical head 20 when the at least one characteristic is greater than the limit value. The on / off module 13 is preferably a means for controlling the supply of the optical head 20.

[0076] The measurement 11, analysis 12 and on / off 13 modules are connected by wired connection means (not shown in this figure), for example by electrical connections. Furthermore, in this example, the control unit 10 is connected to the optical head 20 by an electrical connection 30. The electrical connection 30 is, by way of example, a conductive means, for example an electrical wire, arranged to supply the supply current 40 to the optical head 20.

[0077] In the example illustrated in [Fig.4], the supply current 40 flows from the control unit 10 to the optical head 20. The optical head 20 is therefore supplied by the control unit 10.

[0078] Following the example of [Fig.5], an electrical circuit is formed between the optical head 20 and the control unit 10. Thus, the on / off module 13 can be a means which allows the closing or opening of the circuit formed by the control unit 10 and the optical head 20. By way of example, the on / off module 13 can be a switch or a controlled switch.

[0079] [Fig.6] illustrates another embodiment of the control unit 10.

[0080] The control unit 10 illustrated in [Fig.6] comprises all the elements of the control unit command 10 illustrated in [Fig.5], so only the differences between these figures will be described. The supply current 40 is, for example, an analog signal.

[0081] In this example, the on / off module 13 is a smart switch. A smart switch is understood to mean a switch that is active, i.e. it is configured and arranged to perform actions other than closing or opening an electrical circuit. In the case illustrated in [Fig.6], the on / off module is configured to send the supply current to the measurement module 11.

[0082] The on / off module 13 comprises a passive switch 1311. The switch 1311 comprises two states, an opening state causing the opening of the electrical circuit formed by the control unit 10 and the optical head 20 and a closing state closing the electrical circuit formed by the control unit 10 and the optical head 20. In the example illustrated in [Fig.6], the control unit 10 (and here precisely the analysis module 12) is arranged to send a stop command 15 or an opening command 15 to the on / off module 13 following the comparison step 104. Depending on this command 15, the on / off module 13 opens or closes the switch 1311. Thus, if the condition of the analysis step 104 is reached, the control unit 10 (here, the analysis module 12) sends the stop command 15 to the switch 1311, which goes into the opening state.Otherwise, either when the closing command 15 is transmitted to the on / off module 13, the switch 1311 retains its closed state if it is already closed or goes into the closed state if the switch 1311 was previously in its open state. The supply current 40 can flow from the control unit 10 to the optical head 20.

[0083] The measurement module 11 illustrated in [Fig.6] comprises a conversion module 1111. The conversion module 1111 is configured to convert the supply current 40 into an electrical voltage. The properties of the supply current, in particular the characteristics of the supply current 40, are preserved during the current-voltage conversion. The voltage at the output of the conversion module thus comprises characteristics similar to those of the supply current 40. The measurement module 11 illustrated in [Fig.6] also comprises a digitization module 1113. The digitization module 1113 is configured to digitize said electrical voltage, analog voltage, into a digital value 14 representing a voltage, digital value 14 which is then transmitted to the analysis module 12. The digital value 14 is for example coded on 12 bits. By way of example, the digitization module 1113 is an analog-digital converter.

[0084] In this example, the control unit 10 is powered by a supply current 50 coming from the battery of the vehicle's starting system. The control unit 10 of [Fig. 6] optionally comprises a protection module 16. The protection module 16 serves as an interface between the supply current 50 coming from the battery of the vehicle's starting system and the control unit 10. According to this example, the supply current 50 coming from the battery of the vehicle's starting system is sent to the on / off module 13. The power supply of the control unit 10 is used to trigger the method 100 or 200 for controlling the operation of the optical head 20. Furthermore, in this example, the protection module 16 is connected to the on / off module 13 of the control unit 10. Thus, when the control unit 10 is powered by the battery of the vehicle starting system, the on / off module 13 is arranged to start the supply of the supply current 40 to the optical head, for example by switching the switch 1311 to its closed state. The switching step 202 is therefore carried out. The supply of the supply current 40 to the optical head 20 is started each time the starting system is switched on. Conversely, the on / off module 13 is arranged to stop the supply of the supply current 40 each time said starting system is switched off, i.e. when the control unit 10 is no longer powered by the battery of the starting system. When the vehicle starting system is stopped by the additional stopping step 204, the control unit 10 is no longer powered by the supply current 50.The switch can maintain its closed state or switch to its open state since no supply current 40 flows between the control unit 10 and the optical head 20.

[0085] [Fig.7] illustrates an embodiment of a system according to the invention.

[0086] The system 700 illustrated in [Fig.7] comprises the control unit 10 illustrated in figures 5 or 6 and the optical head 20. The optical head 20 comprises at least one light source 21, in particular one in this example.

[0087] In this example, the light source 21 is a pulsed source. The emission duration can be adjustable or fixed. Thus, the light source can adapt to different needs and situations. The pulse duration of the light source is preferably adjusted by the supply current 40, in particular by the duration of application of the supply current 40. Preferably, the light source 21 is an infrared source, comprising, for example, an emission spectrum between 750 and 1000 nanometers. The emission spectrum of the light source is therefore in the infrared, which avoids disturbing the individual when he is driving because this wavelength range is not seen by the individual's eye. For example, the infrared source emits a wavelength at 850 nanometers. The safety and comfort of the individual are therefore further improved.For example, the light source 21 is an LED or a Vertical Cavity Surface Emitting Laser (VCSEL).

[0088] The example system 700 illustrated in [Fig.7] optionally comprises a sensor 22. The sensor 22 is arranged to acquire at least one image of the individual when said individual is illuminated by said light source 21. The sensor may be a camera, for example a system for acquiring a three-dimensional image with a time-of-flight sensor, or a camera. The sensor 22 is preferably an infrared sensor.

[0089] In the example illustrated in [Fig.7], no supply current 40 flows between the control unit and the optical head 20. The switch 1311 of the on / off module stop 13 is in its open state. The circuit formed by the control unit and the optical head 20 is open.

[0090] [Fig.8] illustrates an example of variation in the supply current 40 recorded by the measuring unit 11 and [Fig.9] illustrates a variation in the light signal 24 emitted by the optical head 20.

[0091] In the variation of [Fig.8], the first threshold 801 and the second threshold 802 are illustrated. For example, the first threshold 801 is set at 6 milliseconds while the second threshold is set at 4.5 amperes (A).

[0092] According to the example of [Fig.8], the supply current 40 has a square wave variation with a high state and a low state 805. The low state is, for example, 0.5 amperes. The low state 805 is preferably greater than or equal to the minimum value which in this example is 0.5 amperes. In the example of [Fig.8], the low state 805 relates to an intensity greater than zero amperes and is equal to a minimum value depending on a residual current. The residual current is, for example, caused by an intrinsic electrical consumption of the optical head 20 when not illuminated. The low state 805 corresponds to a residual noise of the supply current 40. The variation of the supply current 40 comprises a first high state 803 and a second high state 804. According to the example illustrated, as soon as the supply current 40 passes to the high state 803, 804, the control of the duration by the first threshold 801 is triggered.For example, the first threshold 801 is activated as soon as the supply current 40 has an increase greater than 50% of the value of the low state 805, i.e. 50% of the minimum value. For example, a clock of the control unit 10 (preferably of the analysis module 12) configured at the first threshold 801 can be activated. The high states 803, 804 and low 805 are predefined upstream, at the stage of design and / or assembly of the optical head 20 on the dashboard of the vehicle. On leaving the factory, the duration in the high state and the value (in intensity) of this high state are no longer likely to vary or be modified, in particular for safety reasons. In fact, these elements are configured so that they cannot be modified by unqualified persons, for example by the owner of the vehicle or an external operator (to the designer of the optical head) who would be required to intervene on the vehicle in the event of an accident or breakdown.The same applies to the minimum value and / or the percentage of the limit value allowing the time control to be triggered by the first threshold 801. Thus, the time slot relating to the first high state 803 lasts less time and is less than the time slot relating to the second high state 804.

[0093] The first and second slots of the supply current 40 are lower than the second threshold 802. However, in the slot relating to the second high state 804, the supply current 40 is emitted for more than 6 milliseconds. The supply current 40 thus reaches the first threshold 801. The supply current 40 is therefore cut off by the stop step 106. The supply current goes to 0 amperes. The optical head 20 is no longer powered by the control unit 10. Thus, following this example, the first threshold 801 is the first to have been reached and causes the power supply to the optical head 20 to stop even if the second threshold 802 has not been reached.

[0094] The variation of the light signal 24 in [Fig. 9] emitted by the optical head 20 has a variation similar to that of the supply current 40 of the optical head 20. Thus, when the supply current 40 is cut off, the light signal 24 emitted by the optical head 20 is cut off. In the case illustrated in [Fig. 9], the light signal 24 emitted by the optical head 20 comprises a first pulse 901 equal to the duration of application of the supply current 40 of the first high state 803 of the supply current and a second pulse numbered 902 of duration equal to the first threshold 801. When the light source 21 does not emit light and is not cut off following the stopping step 106, the light signal comprises a low level 905 proportional to the low level 805 of the supply current 40.

[0095] Of course, the present invention is in no way limited to the embodiments described and shown, but those skilled in the art will be able to provide any variant in accordance with the invention.

Claims

Claims

1. A method (100, 200) for controlling an optical head (20) intended to be used in a system for observing an individual located inside a passenger compartment of a vehicle, said method (100, 200) using a control unit (10) arranged to supply said optical head (20) with a supply current (40), said method (100, 200) comprising at least one iteration of the following steps: - measurement (102), by the control unit (10), of at least one characteristic of the supply current (40); - analysis (104), by the control unit (10), of the at least one characteristic by comparing the at least one characteristic with a limit value; - stopping (106), by the control unit (10), of a supply of the supply current to the optical head (20) when the at least one characteristic is greater than the limit value, characterized in that the at least one characteristic relates to an intensity of the supply current (40).

2. Control method (100, 200) according to claim 1, characterized in that the limit value is a threshold (802) less than or equal to 10 amperes.

3. Control method (100, 200) according to any one of the preceding claims, characterized in that said vehicle comprises a starting system, said method comprising, prior to the measuring step (102), a step of engaging (202) said optical head (20) each time said starting system is powered up.

4. Control method (100, 200) according to the preceding claim, characterized in that said method (100, 200) is repeated each time the starting system is powered up.

5. Control unit (10) of an optical head (20) intended to be used in a system for observing an individual located inside a passenger compartment of a vehicle, said control unit (10) comprising: - a measurement module (11) arranged to measure at least one characteristic relating to an intensity of a supply current (40) of said optical head (20); - an analysis module (12) arranged to analyze the at least one characteristic by comparing the at least one characteristic with a limit value; - an on / off module (13) arranged to stop a supply of the supply current (40) to the optical head (20) when the at least one characteristic is greater than said limit value.

6. Control unit (10) according to claim 5, characterized in that the on / off module (13) comprises a switch (1311) comprising two operating states, a closed state and an open state, said switch (1311) being arranged to switch to the open state after receiving a stop command from the analysis module (12) to stop the supply of the supply current (40) to the optical head (20).

7. Control unit (10) according to any one of claims 5 to 6, characterized in that said vehicle comprises a starting system, the start / stop module (13) being arranged to start the supply of the supply current (40) to the optical head (20) each time said starting system is switched on and to stop the supply of the supply current (40) each time said starting system is switched off.

8. Control unit (10) according to any one of claims 5 to 7, characterized in that the measurement module (11) comprises a conversion module (1111) configured to convert said supply current (40) into an electrical voltage and a digitization module (1113) configured to digitize said electrical voltage, said digitized electrical voltage (14) being transmitted to the analysis module (12).

9. Control system (700) comprising: - an optical head (20) comprising a light source (21); - a control unit (10) of said optical head (20) according to any one of claims 5 to 8.

10. Control system (700) according to claim 9, characterized in that the light source (21) is a pulsed source.

11. Control system (700) according to any one of claims 9 to 10, characterized in that the light source (21) is an infrared source.

12. Control system (700) according to any one of claims 9 to 11, characterized in that the optical head (20) comprises a sensor (22) arranged to acquire at least one image of said individual when said individual is illuminated by said light source (21).

Images