Object detection method, corresponding electronic device and computer program product

Abstract

The invention relates to a method implemented in an electronic device, the method comprising: Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first area of a scene monitored by said sensors, said first area being at least partially located in the measurement field of said first sensor; Updating an indicator of occupancy of said first area on the basis of said obtained first data; Updating a measurement frequency of at least one second sensor of said plurality of sensors on the basis of a variation in said indicator of occupancy of said first area in a time window. The invention also relates to a corresponding system, electronic device, computer program product and medium.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Object detection method, electronic device and corresponding computer program product

[0003] 1. Technical field

[0004] This application relates to the field of automatic object detection. By object, we mean various physical objects, such as living beings or inert objects. These objects can, for example, be mobile.

[0005] The present application relates in particular to a method for the automatic, or at least partially automatic, detection of at least one object, as well as a corresponding electronic device, computer program product and medium.

[0006] 2. State of the art

[0007] Automatic object detection is a growing technique, used in many fields. For example, home automation often implements automatic motion detection to turn on a light when a person enters a room, or to automatically open a door when an individual approaches. We can also mention video surveillance solutions. These make it possible to identify objects, monitor their condition and / or track their comings and goings, regardless of the type of object concerned. Thus, it can be a static object to be monitored (for example, a static object whose malfunction would result in a change in its appearance (vibrations, appearance of smoke, etc.) that needs to be detected, or a mobile object, such as a vehicle, a living being, a wave, etc.). However, video surveillance solutions can be expensive and complex to implement.For example, they may require the installation of a wired network infrastructure, equipment power supply, analysis processing and image identification.

[0008] In addition, video-based solutions require compliance with various European laws, including the General Data Protection Regulation (GDPR), which limits the retention and use of "personal" data, and privacy laws. Compliance with these regulations can impose significant constraints from a technical point of view, both in terms of processing times (which must, for example, be less than a retention period for certain data) and the nature of the data processed and the processing carried out, which can limit the applications of these solutions, particularly for professional uses, which often require complex processing.

[0009] The present application aims to propose improvements to at least some of the disadvantages of the state of the art.

[0010] 3. Statement of the invention

[0011] The present application aims to improve the situation using a method implemented at least partially in an electronic device and comprising: obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor; updating a measurement frequency of at least one second sensor of said plurality of sensors as a function of a variation in an occupancy of said first zone over a time window.

[0012] In certain embodiments, the method comprises an update of an occupancy indicator of said first zone as a function of said first data obtained and said updating of said measurement frequency of at least one second sensor of said plurality of sensors is a function of a variation of said occupancy indicator of said first zone over a time window.

[0013] In some embodiments, said first sensor is a distance sensor and said first data comprises at least one indication of distance relative to said first sensor, said at least one first physical element.

[0014] In some embodiments, the sensors of said plurality of sensors are distance sensors.

[0015] In at least one embodiment, said first sensor comprises one of said at least one second sensor.

[0016] In at least one embodiment, said updating of said measurement frequency of said at least one second sensor comprises an increase, respectively a decrease, in the measurement frequency of said first sensor when said occupancy indicator of said first zone is representative of an increase, respectively a decrease, in the occupancy of said first zone.

[0017] In at least one embodiment, said updating of said measurement frequency of said at least one second sensor takes into account the energy consumed by all of said plurality of sensors over said time window.

[0018] In at least one embodiment, a sensor other than said first sensor is one of said at least one second sensor.

[0019] In at least one embodiment, said updating of said measurement frequency of said at least one second sensor comprises a decrease, respectively an increase, in the measurement frequency of said at least one other sensor of said plurality of sensors, when said occupancy indicator of said first zone is representative of an increase, respectively a decrease, in the occupancy of said first zone.

[0020] In at least one embodiment, said other sensor is selected, from said plurality of sensors, based on occupancy indicators of the areas monitored by said plurality of sensors, obtained from the measurements of said plurality of sensors.

[0021] In at least one embodiment, the method comprises:

[0022] Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor;

[0023] An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

[0024] In at least one embodiment, the method comprises an update of an occupancy indicator of said first zone as a function of said first data obtained and said updating of said measurement frequency of at least said first sensor is a function of a variation of said occupancy indicator of said first zone over a time window. In at least one embodiment, said first sensor is a distance sensor and said first data comprises at least one distance indication relative to said first sensor, of said at least one first physical element.

[0025] In at least one embodiment, said updating of said measurement frequency of said at least one first sensor comprises an increase, respectively a decrease, of the measurement frequency of said first sensor during an increase, respectively a decrease, of the occupancy of said first zone.

[0026] In at least one embodiment, the method comprises updating a measurement frequency of at least one second sensor of said plurality of sensors, other than said first sensor, as a function of a variation in an occupancy of said first zone over a time window.

[0027] In at least one embodiment, said updating of said measurement frequency of said at least one second sensor comprises a decrease, respectively an increase, in the measurement frequency of said at least one second sensor of said plurality of sensors, during an increase, respectively a decrease, in the occupancy of said first zone. In at least one embodiment, said updating of said measurement frequency of said at least one first and / or second sensor takes into account the energy consumed by all of said plurality of sensors over said time window.

[0028] In at least one embodiment, said second sensor is selected, from among said plurality of sensors, based on occupancy indicators of the areas monitored by said plurality of sensors obtained from the measurements of said plurality of sensors.

[0029] In at least one embodiment, the measurement fields of said plurality of sensors are disjoint.

[0030] In at least one embodiment, at least two sensors of said plurality of sensors have identical measurement directions (i.e. parallel measurement field axes).

[0031] In at least one embodiment, at least two sensors of said plurality of sensors have different measurement directions (non-parallel measurement field axes). In at least one embodiment, the measurement directions of at least two sensors of said plurality of sensors are located in the same acquisition plane (in other words in the same measurement plane). In at least one embodiment, said at least two sensors are aligned and said acquisition plane is defined by an alignment of said at least two sensors and by said measurement directions.

[0032] In at least one embodiment, said acquisition plane is a plane perpendicular to a main direction of movement of object(s) of said scene to be monitored.

[0033] In at least one embodiment, the method comprises a reconstruction of at least one 3D shape from the data obtained from the sensors and relating to the elements measured in said acquisition plane at different measurement times.

[0034] In at least one embodiment, at least two sensors of said plurality of sensors are integrated into a single support coupled to said device.

[0035] In at least one embodiment, said support is orientable.

[0036] In at least one embodiment, said support is breakable.

[0037] In at least one embodiment, said support can be mechanically and / or electronically assembled with another support of at least one sensor of said plurality of sensors. The characteristics, presented in isolation in the present application in connection with certain embodiments of the method of the present application, can be combined with each other according to other embodiments of the present method.

[0038] According to another aspect, the present application also relates to an electronic device suitable for implementing the method of the present application in any of its embodiments. For example, the present application thus relates to an electronic device comprising at least one processor configured for: obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor updating a measurement frequency of at least one second sensor of said plurality of sensors as a function of a variation in an occupancy of said first zone over a time window.

[0039] The present application also relates, for example, to an electronic device comprising at least one processor configured to:

[0040] Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor;

[0041] An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window. The present application also relates to a computer program comprising instructions for implementing the various embodiments of the above method, when the computer program is executed by a processor and a recording medium readable by an electronic device and on which a computer program is recorded.

[0042] For example, the present application thus relates to a computer program comprising instructions for implementing, when the computer program is executed by a processor of an electronic device, a method comprising: obtaining first data from at least one first sensor of a plurality of distance sensors, said first data comprising at least one indication of distance relative to said first sensor, of at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor; updating a measurement frequency of at least one second sensor of said plurality of sensors as a function of a variation in an occupancy of said first zone over a time window.

[0043] The present application also relates, for example, to a computer program comprising instructions for implementing, when the computer program is executed by a processor of an electronic device, a method comprising:

[0044] Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor;

[0045] An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

[0046] For example, the present application also relates to a recording medium readable by a processor of an electronic device and on which is recorded a computer program comprising instructions for implementing, when the computer program is executed by the processor, a method comprising: obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor updating a measurement frequency of at least one second sensor of said plurality of sensors as a function of a variation in an occupancy of said first zone over a time window.For example, the present application also relates to a recording medium readable by a processor of an electronic device and on which is recorded a computer program comprising instructions for implementing, when the computer program is executed by the processor, a method comprising:

[0047] Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor;

[0048] An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

[0049] The above-mentioned program may use any programming language, and may 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 form.

[0050] The recording (or information) media mentioned in the present application may be any entity or device capable of storing the program. For example, a medium may comprise a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a magnetic recording means. Such a storage means may for example be a hard disk, a flash memory, etc.

[0051] On the other hand, an information carrier may be a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means. A program according to the invention may in particular be downloaded from a network such as the Internet. Alternatively, an information carrier may be an integrated circuit in which a program is incorporated; in the present application, the circuit is adapted to execute or to be used in the execution of any of the embodiments of the method which is the subject of the present patent application.

[0052] Generally speaking, by obtaining an element, we mean in the present application for example a reception of this element from a communication network, an acquisition of this element (via for example user interface elements or sensors), a creation of this element by various processing means such as by copying, encoding, decoding, transformation etc. and / or an access of this element from a local or remote storage medium accessible to at least one device implementing, at least partially, this obtaining.

[0053] 4. Brief description of the drawings

[0054] Other characteristics and advantages of the invention will appear more clearly on reading the following description of particular embodiments, given as simple illustrative and non-limiting examples, and the appended drawings, among which: [Fig 1] presents a simplified view of a system, cited as an example, in which at least certain embodiments of the method of the present application can be implemented,

[0055] [Fig 2] presents an example of implantation, on a support, of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of at least certain embodiments of the method of the present application,

[0056] [Fig 3] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of at least certain embodiments of the method of the present application,

[0057] [Fig 4] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of certain embodiments of the method of the present application,

[0058] [Fig 5] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of certain embodiments of the method of the present application,

[0059] [Fig 6] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of certain embodiments of the method of the present application,

[0060] [Fig 7] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of certain embodiments of the method of the present application,

[0061] [Fig 8] presents an example of positioning of sensors adapted to be coupled with the device 100 of FIG. 1 for the implementation of certain embodiments of the method of the present application,

[0062] [Fig 9] shows an overview of the method of processing the present application, in some of its embodiments.

[0063] [Fig 10] shows an example of delimitation of zones in a monitored scene, for the implementation of certain embodiments of the method of the present application,

[0064] 5. Description of embodiments

[0065] The present application proposes a solution for detecting movements and / or presence based on data from a plurality of sensors, each monitoring a portion (fixed for example) of a scene to be monitored. This may involve, for example, detecting the passage of a mobile object in the monitored scene.

[0066] According to the embodiments, the plurality of sensors may be a homogeneous or heterogeneous plurality of sensors. For example, the sensors may implement different technologies. Thus, in certain embodiments, at least one sensor of this plurality of sensors (for example all) may be a sensor not using the results of a video capture, such as a sensor measuring a distance between this sensor and a distant part (or element) (a wall, a door, a floor, a person, an animal, a moving object, etc.), facing each other for example. According to the embodiments, the sensor may for example implement different types of laser technology (visible or non-visible, audible or not, etc.) to measure this distance (by emitting a laser beam). It may also be an infrared (IR) technology in certain embodiments. Such sensors are referred to in the remainder of the application as a “distance sensor”.These sensors measure their distance from the reflection points of their capture field and thus make it possible to detect a new presence or movement of an object due to the changes in distance that it induces in their capture field. This may be, for example, the new presence of an inert object or that of an animated object. An example of a distance sensor is the VI53I1 sensor from the company STMicro ©. Of course, other sensors can be used without departing from the scope of this application.

[0067] In some embodiments, the characteristics of at least some of the sensors (of the same or different natures) may differ, for example in terms of detection distance or measurement (or capture) field (or FoV for "Field of View" according to English terminology). Thus, some sensors may operate over short distances (a few millimeters to a few tens of centimeters), others over medium distances (a few tens of centimeters to a few meters (for example 2 to 4 meters)) or long distances (a few meters to a few tens or a few hundred meters). These sensors may also have a perfectly focused detection radius (0° measurement field angle), very focused (a few degrees), or less focused (several degrees to a few tens of degrees).

[0068] In such embodiments, at least some of the sensors of the plurality of sensors can operate independently of one another. In such embodiments, a failure (damage or wear for example) of one of these independent sensors will therefore have no (or little) impact on the operation of another of these independent sensors. Therefore, if for example these sensors each monitor an area of ​​a scene to be monitored, in its entirety, by the plurality of sensors, the potential impact of the failure on the capture of the scene will be limited to the portion (of the scene) monitored by the defective sensor.

[0069] The solution of the invention can therefore be shown, at least in certain embodiments, to be more resilient than certain capture systems based on a single sensor scanning the space around it due to its own mobility or the mobility of a reflector (such as a LIDAR type sensor (for "light detection and ranging" or "laser imaging detection and ranging" according to English terminology).

[0070] For the sake of simplicity, it will be considered in the remainder of the application that all the sensors of the plurality of sensors operate independently of each other, with their own data capture (i.e. measurement or acquisition) frequency. The capture frequencies may differ depending on the sensors of the plurality of sensors. Such embodiments may allow, for example, unlike certain capture systems based on a single sensor scanning the space around it at a constant frequency, to vary the data capture frequency according to the areas of the scene to be monitored. For example, it may be possible to monitor certain critical areas more (more frequently) than certain less critical areas.Such embodiments can, for example, help to improve responsiveness to these critical areas (for example, areas in the immediate vicinity of a cash dispenser), and / or help to limit the energy expended by the capture, by monitoring less critical areas (for example, areas further away from this cash dispenser) with a lower frequency.

[0071] In some embodiments, at least one sensor of the plurality of sensors (for example, one, several or all) may have an adjustable capture frequency. Such an embodiment may make possible dynamic adaptation to events occurring in the monitored scene (or, more generally, dynamic adaptation to the capture situation of the monitored scene). Thus, the invention may allow in some embodiments a characterization, in terms of occupation (presence and / or movement) of at least one zone (or portion) of the monitored scene. For example, it may be a quantification (relative to the other zones or in absolute terms) of an occupancy of the zone. This quantification may be translated by an occupancy identifier calculated for example dynamically, and representative of an occupancy frequency of a zone or an occupancy density of a zone.Such quantification can help identify areas that are more / less frequently occupied, and / or have the highest occupancy density (when a sensor has multiple capture points in the same area). Depending on the embodiments, the occupancy identifier may relate to a current occupancy of an area or to an occupancy of the area over a period of time (such as a reference period, such as a duration of a few seconds, a few minutes or a few hours depending on the embodiments).Adjusting (or adjusting) the capture frequency of at least one sensor of the plurality of sensors may increase the capture frequency of certain sensor(s) corresponding to frequently and / or densely occupied areas (such as the most frequently and / or densely occupied areas), and reduce the capture frequency of sensor(s) monitoring areas where very little activity occurs (such as unoccupied or very lightly occupied areas and / or the least frequently and / or densely occupied areas). It may also involve maintaining the frequency of certain sensors and varying (increasing or reducing) the frequency of other sensors.

[0072] Note that the term “reduce” includes a drop in frequency or even a software and / or hardware standby or shutdown of certain sensors.

[0073] In some embodiments, it may be possible to reduce the acquisition frequency of all the sensors (or some of these sensors) when no movement (i.e. change in measured distance) has been detected for a certain time (or alternatively little movement), and to dynamically increase the acquisition frequency of all or some of the plurality of sensors when a movement (or a presence) is detected in one or more zones monitored by the plurality of sensors. This may involve, for example, increasing the acquisition frequency of at least one distance sensor that has detected a presence or movement in its measurement field, (or even all the distance sensors that have detected a presence or movement in their measurement field). For example, the frequency of a sensor may be increased when the measured distances vary, and be slowed down when the measured distances are unchanged.This involves changing the frequency of a sensor while an object passes by (for example, for a few seconds or a few minutes).

[0074] The present application thus proposes a dynamic adjustment of the capture frequencies depending for example on the presences and / or movements detected in the monitored scene, unlike certain solutions of the prior art, such as those based on a single sensor whose measurement field varies. The measurement frequency of such a sensor will in fact be the same (i.e. identical) across the entire monitored scene.

[0075] The present application is now described in more detail in connection with Figure 1. Figure 1 illustrates a system comprising at least one electronic device 100 adapted to implement the principles of the present application and of which Figure 1 shows the simplified structure. Depending on the embodiments, the electronic device 100 may be a server, and / or a terminal (such as a laptop, a smartphone, or a tablet).

[0076] The device 100 may comprise at least one memory M 110. The device 100 may in particular comprise a buffer memory, a volatile memory, for example of the RAM type (for “Random Access Memory” according to English terminology), and / or a non-volatile memory (for example of the ROM type (for “Read Only Memory” according to English terminology). The device 100 may also comprise a processing unit UT 120, equipped for example with at least one processor P 122, and controlled by a computer program PG 112 stored in memory M 1 10. On initialization, the code instructions of the computer program PG are for example loaded into a RAM memory before being executed by the at least one processor P 122.The at least one processor P 122 of the processing unit UT 120 can in particular implement, individually or collectively, any one of the embodiments of the method of the present application (described in particular in relation to FIG. 3), according to the instructions of the computer program PG.

[0077] According to the embodiments, the at least one computer program PG may be a single program, executed on a single processor of the device 100 or comprise several programs, duplicated at least partially and / or distributed to execute on several processors of said device.

[0078] The device may also comprise, or be coupled to, at least one I / O input / output module 130, such as a communication module, allowing for example the device 100 to communicate, via wired (Ethernet, USB (for Universal Serial Bus according to English terminology) or USB-, ....) or wireless (Wifi, etc.) communication interfaces of the device 100, with one or more other devices 150, 160 of at least one communication network. This communication network may be a communication network to which the device 100 belongs and / or a network interconnected (directly or indirectly) with such a communication network to which the device 100 belongs; It may be a local area network or LAN (Local Area Network) according to English terminology, and / or a wide area network, or WAN (Wide Area Network) according to English terminology.For example, the device may belong to a corporate or home LAN network and be interconnected with a WAN network such as the internet, or cellular, GSM - Global System for Mobile Communications, UMTS - Universal Mobile Telecommunications System, Wifi - Wireless, etc.).

[0079] An “other” device with which the device 100 is capable of communicating may be, for example, a terminal, a server, for example an application server, a storage device, a management and / or network interconnection device. It may also be a sensor 150 allowing the device 100 to acquire information on a portion of a physical environment, also called a “scene to be monitored”, and in particular information relating to the presence and / or movements of various objects in the portion of the physical environment.

[0080] One or more sensors may also be integrated into the device 100.

[0081] In some embodiments, one or more sensors may be mounted on a support coupled (e.g., removably) to the device, for example via connections, which may or may not be magnetic as defined in the applicant's patent FR3118524. In the detailed embodiments, the device is thus coupled to several sensors, such as distance sensors as discussed above.

[0082] By "coupled" (or coupling) is meant here an adaptation of the device to obtain information from these sensors, whether via a data bus internal to the device (in the case of a sensor integrated into the device) or via communication means of the device and / or at least one communication network in the case of a sensor external to the device, as illustrated in figure 1.

[0083] In some embodiments, the device may also have the ability to act on the operation of at least one of these sensors. For example, the device may have the ability to put a sensor into operation and / or into standby mode and / or to dynamically configure it (during its operation for example). In particular, the device may also have the ability to modify the capture frequency (i.e. measurement) of at least certain sensors during their operation.

[0084] Mentioned above are embodiments where sensors are mounted on a removable support that can be attached to the device 100. In other embodiments, at least one sensor can be mounted on a support (for example remote) comprising, similarly to the device 100, at least one memory (including a RAM memory), at least one processing unit equipped with at least one processor (microcontroller) and controlled by a computer program stored in memory and at least one input / output module, such as a communication module, allowing in particular the support to communicate, via wired or wireless communication interfaces, on the one hand with the device 100 and on the other hand with at least some of the sensors and / or (optionally) with at least one other support on which at least one sensor of the plurality of sensors is mounted.

[0085] In some embodiments, the medium may serve as a relay between the sensors and the device 100, the at least one PG program executing on the device 100. In other embodiments, the at least one PG program may be distributed between the device 100 and at least one medium as described above. The device 100 may, for example, communicate via a CAN bus with a sensor medium.

[0086] The sensors may include means of wired or wireless communication with the device 100 or with a microcontroller of the support on which they are mounted and / or with which they interact (for example an I2C type communication bus (for Inter-integrated circuit according to English terminology).

[0087] In certain embodiments, a sensor support(s) may comprise assembly means (mechanical and / or electronic) with another sensor support(s). It will be noted that according to the embodiments, in the case of an assembly of supports, each assembled support may be equipped with a microcontroller, or only some of the assembled supports (the sensors of a support without a microcontroller then communicating directly with the device 100 or with a microcontroller of another support with which it is assembled (via an I2C bus for example).

[0088] It is noted that the physical environment on which the sensors feed information back to the device 100 may be distinct from the device 100's own environment. For example, in some embodiments, the device and at least some of the sensors may be located in different locations. Similarly, the physical environment of the sensors may differ depending on the sensors. In particular, the device 100 may obtain information from several groups of sensors each located in a different physical environment. For example, the device 100 may obtain information from several groups of several sensors each located in a different room of the same home or the same business.

[0089] It is noted that the positioning of the sensors within the same environment may vary according to the embodiments as illustrated by figures 2 to 8 by the present application. The I / O input / output modules 130 may in particular allow the device to send data to a third-party device, such as data originating at least partially from at least one sensor 150 coupled to the device 100 (or data resulting from the processing of such data) or to receive data and / or an update of a code to be executed by the processor P 122 of the device 100). The I / O input / output modules may comprise at least one module for interfacing with a user of the device (also called more simply in this application “user interface”).

[0090] By user interface of the device, we mean for example an interface integrated into the device 100, or a part of a third-party device coupled to this device by wired or wireless communication means. For example, it may be a secondary screen of the device or a set of speakers connected by wireless technology to the device.

[0091] A user interface may in particular be a user interface, called an “output” user interface, adapted to a rendering (or to the control of a rendering) of an output element of a computer application used by the device 100, for example an application running at least partially on the device 100 or an “online” application running at least partially remotely, for example on a server. Examples of output user interfaces of the device include one or more screens, in particular at least one graphic screen (touch screen for example, 2D or 3D and / or holographic), one or more speakers, a connected headset, light-emitting diodes (LEDs) (or LED for “Light-Emitting Diode” according to the English terminology), a vibration generator. A graphic screen may for example allow a rendering of a 3D reconstruction as mentioned below

[0092] By rendering, we mean here a restitution (or “output” according to English terminology) on at least one user interface, in any form, for example including textual, audio and / or graphic, light, vibrational components etc. or a combination of such components.

[0093] Furthermore, a user interface may be a so-called “input” user interface, adapted to acquiring a command from a user of the device 100. This may in particular be an action to be performed in connection with a returned item, and / or a command to be transmitted to a computer application used by the device 100, for example an application running at least partially on the device 100 or an “online” application running at least partially remotely, for example on a remote server.Examples of user input interface of the device 100 include a sensor (for example a sensor adapted to detect a gesture or a mimic of a user or an administrator of the device (and thus capable of detecting gestures comparable to commands), an audio and / or video acquisition means (microphone, camera (webcam) for example), a keyboard, a mouse, mechanical or electromechanical actuators (buttons, joysticks, etc.) As illustrated in FIG. 1, the device 100 may further comprise at least one module 140 for supplying energy to the different modules of the device. The energy may come from batteries, or come from the mains, and / or from ambient energy (such as solar energy for example).In the case of ambient energy, the module may comprise or be coupled to at least one element for capturing ambient energy, and comprise at least one element for transforming this ambient energy into energy capable of being consumed by the modules of the device 100 (such as electrical energy for example), as well as possibly an energy storage module before its consumption.

[0094] In some embodiments, the module 140 may power the device and the elements to which it is coupled (sensors, support, etc.). In other embodiments, separate modules may power the device 100, at least some of the sensors and / or their possible support.

[0095] The different modules of the device can communicate with each other, depending on the embodiments, synchronously or asynchronously.

[0096] Said at least one microprocessor of the device 100 may in particular be adapted for: obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor; updating a measurement frequency of at least one second sensor of said plurality of sensors as a function of a variation in an occupancy of said first zone over a time window.

[0097] In certain embodiments, said at least one microprocessor of the device 100 may in particular be adapted for updating an occupancy indicator of said first zone as a function of said first data obtained, and an update of a measurement frequency of at least one second sensor of said plurality of sensors may take into account a variation of said occupancy indicator of said first zone over a time window.

[0098] In certain embodiments, said at least one microprocessor of the device 100 may in particular be adapted to:

[0099] Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor;

[0100] An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

[0101] Some of the above input-output modules are optional and may therefore be absent from the device 200 in certain embodiments. In particular, if the present application is sometimes detailed in connection with a device 100 communicating with at least one other device (for example a supervision server, and / or a distance sensor external to the device, and / or a support equipped with such a sensor) the method can also be implemented locally by the device 100, when at least some of the sensors of the system 100 are integrated into the device. On the contrary, in some of its embodiments, the modules described above can be distributed between at least two devices (some modules possibly being present on several devices (identical or different modules but with similar functionalities) as on the device 100 and a physical support of at least one distance sensor as mentioned above).

[0102] The term "module" or the term "component" or "element" of the device is understood here to mean a hardware element, in particular wired, or a software element, or a combination of at least one hardware element and at least one software element. The method according to the invention can therefore be implemented in various ways, in particular in wired form and / or in software form.

[0103] Figure 9 illustrates certain embodiments of the method 900 of the present application. The method 900 may for example be implemented by the electronic device 100 illustrated in Figure 1. According to Figure 9, the method 900 may comprise a configuration 910 of the device 100. This configuration 910 may in particular comprise obtaining at least one piece of contextual information from the device such as topographical information relating to the scene to be monitored and / or to the physical environment in which the scene is located. This may be information relating to the dimensions of the scene to be monitored, to the location in the scene of points of passage of objects such as a door, etc. It may also be a designation in the monitored scene of at least one point of passage and / or at least one area considered critical (sensitive) with respect to the monitoring.Such topographical information may for example be obtained by read access to a data structure such as a configuration file, or such as a database, local or remote. Such topographical information may be obtained, according to another example, via a human-machine interface and / or via certain sensors, already installed, of the plurality of sensors or via sensors other than the plurality of sensors, such as an inclinometer or an accelerometer. This configuration 910 and / or this obtaining of topographical information may be optional in certain embodiments.

[0104] As illustrated in Figure 9, the method 900 may comprise a positioning 920 of at least one sensor in the physical environment of the scene to be monitored. This positioning may be optional in certain embodiments, at least for certain sensor(s). The positioning of at least one sensor may comprise its “physical” installation and / or its orientation, the installation as well as the orientation being able to be optional in certain embodiments. For example, certain sensors may have already been positioned during a previous implementation of the method that is the subject of the present application, and / or already be present in the physical environment of the scene to be monitored before any implementation of the method. Thus, at least one sensor may have been integrated into an infrastructure element of the physical environment of the scene to be monitored (door frame, false ceiling, beam, slab, sleepers, gantry, floor, covering of a traffic lane).Additionally, some sensors (or the bracket they are mounted on) may be fixed in orientation.

[0105] The positioning of a sensor can be implemented at least partially automatically in certain embodiments. It can, for example, take into account positioning rules, positioning data from the sensors themselves and / or other data, known to the device (obtained for example during configuration), such as data relating to the physical space where the sensors will be installed (ceiling height, height of a door, size of a room, etc.) or data acquired by other sensors, such as an inclinometer or an accelerometer.

[0106] It is noted that the positioning of the sensors within the same physical environment may vary depending on the embodiments. For example, in certain embodiments, several sensors 150 among the sensors coupled to the device 100 may be positioned linearly, relative to each other. At least some of the sensors of the plurality of sensors may for example be arranged so that the main capture directions (or measurement directions) of the sensors are located in the same plane (thus forming a virtual wall (or virtual curtain). This plane is defined for example by the sensors and the longitudinal axes of their measurement fields. For example, the longitudinal axes of the sensors may be parallel to each other.As mentioned above, certain sensors may in particular be installed on the same physical support 200 (such as a printed circuit) forming what will sometimes subsequently be called a “sensor strip”, as illustrated in FIG. 2. As a simple non-limiting example, such a strip may have a length of the order of 20 to 40 cm (for example 30 cm), the sensors being for example spaced a few centimeters apart (such as 1 to 3 cm). The support may be assemblable, and / or divisible and / or disassemblable (i.e. separable into at least two supports of a smaller size than the “assembled” support), in certain embodiments, so as to allow its length to be adapted to the desired positioning of the support. For example, a pre-cut 210 (of various shapes depending on the embodiments) may be arranged between at least two sensors of the support (for example between each sensor).

[0107] In some embodiments, the sensor support may be orientable. Such an embodiment may help to position the sensors of the support (and therefore their capture field) at a particular angle (relative to the ground for example). Depending on the embodiments, the support may be orientable manually or by motorization. In particular, its orientation may be controllable remotely (by the device 100 or via a remote control).

[0108] In certain embodiments, the sensor support may comprise means for assembly (directly or via a connector) with another support, for example to define more complex shapes of series of sensors (such as right-angled shapes, such as "L"; "E" or "U" shapes, or assemblies with a 45° angle) or to create groups of sensors (such as bars) of larger size (total length and / or width).

[0109] Depending on the implementations of the invention, the positioning of the sensors may vary. For example, a group of sensors (such as a sensor bar) may be positioned near a point or passageway (indoors or outdoors) in a scene to be monitored. The sensors may in particular be positioned high up, with a capture field towards the ground, so as to form a virtual detection “wall” (or curtain) in the passageway (ideally, of the same width as the passageway). An object crossing the scene will in all likelihood use the passageway, thus crossing the “virtual wall”. In an implementation in an interior space (such as a home, a store or a business), certain sensors may for example be positioned on the ceiling.As an example, Figures 3 and 4 illustrate respectively the positioning of a sensor strip on the ceiling, above a door (Figure 3) or in a corridor (Figure 4) forming a vertical detection wall (perpendicular to the floor). In such an implementation mode, the passage of an object through the detection wall results in a "top view" of this object. In this example, the passage area is entirely (or almost entirely) covered by the measurement (or detection) fields of the sensors. Figures 5 and 6 illustrate respectively the positioning of a sensor strip on the ceiling, near a door (Figure 5) or in a corridor (Figure 6), forming a detection wall inclined relative to the floor (for example at 45° relative to the floor).In such an implementation mode, the passage of an object through the detection wall results in a “low-angle view” of the object (for example a head-to-toe view in the case of a person) via the plurality of sensors. Different (and notably more complex) positionings of the sensors can be implemented depending on the embodiments (depending for example on the application cases, and the physical characteristics (dimensions, shape, etc.) of the location where the sensors are installed), and / or the type of objects whose detection is expected. For example, in certain embodiments, at least some of the sensors can be positioned in a vertical plane (for example on a wall near a passage area) or on the ground. Some sensors of the plurality of sensors can for example be positioned on a first wall and other sensors on a second wall etc. These examples are of course not limiting.For example, in certain embodiments where the expected objects are people, the point cloud corresponding to a person passing under an inclined detection wall (or curtain) (low angle) may sometimes be more representative of this person for a user of the device, than a point cloud corresponding to the passage of this same person under a vertical detection wall (view from above or below). For example, the rendering of a point cloud associated with the inclined detection wall may sometimes help a user more easily to recognize a person than the rendering of a point cloud associated with the vertical detection wall.

[0110] Depending on the embodiments and the sensors used (and their technology), the relative positioning of the sensors may vary. For example, in some embodiments, the plurality of sensors may consist of identical, equidistant sensors (e.g., forming the points of an equilateral triangle), or sensors (e.g., of different characteristics) whose distance from each other may vary depending on the sensors.

[0111] In some embodiments, the plurality of sensors may be partitioned into several groups of sensors of distinct alignment and / or orientation (for example into two groups positioned along two distinct parallel lines) so as to form two different detection (curtain) walls, parallel or with different orientations. Thus, Figures 7 and 8 respectively illustrate the positioning of two sensor strips on the ceiling (parallel to each other for example). In the example of Figure 7, one of the strips is positioned above a door and the second strip is positioned near the door. In the example of Figure 8, the two strips are located in a corridor. In the example of Figure 7 as in that of Figure 8, the two strips form two detection walls, one vertical and the other inclined relative to the ground.

[0112] Such embodiments can make it possible to obtain several series of measurements (one series of measurements per group of sensors), corresponding to different capture angles, which can then be correlated during data analysis or help in the reconstruction of 3D shapes (see below).

[0113] In some embodiments, some sensors may be positioned so as to give thickness to the “virtual detection wall”. For example, sensors may be arranged perpendicular to a row of sensors forming a virtual wall perpendicular to a point / place of passage (so as to obtain a comb shape). According to another example, sensors may be arranged in a staggered pattern, the portion of the monitored scene located between the capture fields of the two sensors (or at their periphery) being located in the measurement field of another sensor. For example, at least two rows of sensors may be positioned in a staggered pattern. These may be parallel or non-parallel rows and of identical or different sizes. Such a staggered arrangement may limit the distance between the sensors and therefore help to make the monitoring of the scene in question more reliable and to obtain more precise detection.For example, if sensors are arranged perpendicular to a direction of travel (e.g. on the ceiling and pointing towards the floor), a staggered arrangement can help achieve higher resolution detection, and therefore help improve passage detection in the direction of travel.

[0114] In certain embodiments, the positioning 920 of the sensors may take into account a usual direction of movement of objects in said scene to be monitored. A usual direction of movement is also called main direction of movement or majority direction of movement in the present application. It may be obtained by accessing a history of movement detection in the monitored scene or via input from a user of the device or access to a configuration file. For example, if the monitored scene is a door of a building, the movements of people using this door to enter and exit the building will a priori statistically be in a direction perpendicular to this door.

[0115] At least some of the sensors may be aligned perpendicular to the main direction of movement of the monitored scene. For example, as discussed in connection with Figures 3 to 6, at least some of the sensors may be aligned and / or oriented such that the virtual wall is perpendicular to the main direction of movement of the monitored scene (i.e., in other words, with an alignment and an acquisition direction forming a plane perpendicular to the direction of movement) or such that the virtual wall is “tilted” relative to the main direction of movement of the monitored scene.

[0116] Alternatively to the examples discussed above, the sensors may be positioned in any two-dimensional or three-dimensional shape, such as a cube, a half-sphere, or a pyramid. Such embodiments may help to achieve a 3D (rather than 2D as in the case of a virtual wall) sensing “space.” For example, 360-degree sensing may be implemented in some embodiments.

[0117] Thanks for example to the positioning of sensors on three-dimensional shapes, or as mentioned above, by the use of several groups of sensors of different location and / or orientation, or of different combinations of sensor bars, certain embodiments of the present application can for example be adapted to presence detection in several directions at the same time (such as simultaneous monitoring of several access doors to a scene).

[0118] The positioning of the sensors can in particular be adapted to detect the direction of movement of the detected objects. Thus, several groups of sensors (for example 2 parallel bars), perpendicular to the main direction of movement of the objects to be detected, will detect the passage of the same object at different times, which can make it possible (using the timestamps of the measurements) to detect a direction of movement of this object. Alternatively, a 3D reconstruction (see below) over a time window can be used.

[0119] The positioning of the sensors may finally include a coupling (not illustrated), wired or wireless, of the sensors to the device 100 (as detailed in connection with figure 1).

[0120] The sensors of the plurality of sensors may for example be chosen and positioned so that their capture fields are distinct (or even disjoint). For example, in certain embodiments, at least some of the sensors may have a detection radius sufficiently focused to limit the overlaps between their own capture field and the capture fields of neighboring sensors. According to another example, the sensors may be spaced from each other taking into account the width of their capture fields (FoV for Field of View in English), so as again to avoid overlaps.

[0121] Using sensors with distinct (and in particular disjoint) capture fields makes it possible to virtually delimit different zones in the monitored scene, depending on the capture fields of the sensors. An area of ​​the scene is thus associated with a subset of the plurality of sensors corresponding to the sensors whose capture field covers, at least partially, the area. For example, in certain embodiments where the capture fields are disjoint, the scene can be virtually divided into zones each associated with a sensor of the plurality of sensors.

[0122] It will be noted that in certain embodiments, the sensors can be positioned so as to monitor only a portion of the physical environment, i.e. to exclude from the scene monitored by the different detection fields at least one same area of ​​the physical environment (such as an office for example).

[0123] In some embodiments, the method may comprise an association 930 with at least one sensor of a criticality index, depending on the criticality of the area that it monitors. The criticality of an area may for example depend on the nature of the passageway (an emergency exit for example).

[0124] According to the embodiments, the criticality of an area can be defined prior to the execution of the method of the present application (by configuration for example) or dynamically, taking into account for example parameters such as the occupancy index of the area (therefore the frequency and / or density of passage in the area). The areas of highest traffic can thus be identified dynamically over time as critical areas. These critical areas can vary depending on the time and the day (for example depending on the hour or time of day).

[0125] As illustrated in FIG. 9, the method 900 may comprise a parameterization 940 of at least one sensor coupled to the device (for example of each sensor coupled to the device 100). For example, the method may comprise a parameterization 942 of the capture frequency of at least one sensor. The capture frequency may be chosen according to the types of objects whose presence and / or movement are to be detected. For example, it may be adapted to the detection of a person walking in the monitored scene.

[0126] In some embodiments, the same capture frequency may be assigned to several sensors (for example, all of the sensors in the plurality of sensors may be configured with an identical frequency). In some embodiments, the sensors in the plurality of sensors may be configured with different frequencies depending on the sensors. For example, in the case of a row of sensors (for example, a strip of sensors), when the relative positioning of the sensors in the row is known to the device, the sensors located at the ends of the row may be configured by default at a higher (respectively lower) capture frequency than that of the sensors located between these “end” sensors.

[0127] The setting of the capture frequency of a sensor may also take into account in certain embodiments a criticality of the area monitored by the sensor. For example, when certain areas of the scene are considered more critical than others, the sensors monitoring these “more critical” areas may be set to a higher capture frequency than the sensors monitoring less critical areas.

[0128] Optionally, the configuration of the sensors may also include, in certain embodiments, a time synchronization 944 of at least some of the sensors, so as, for example, to simultaneously (or almost simultaneously) carry out at least one measurement following this synchronization. This time synchronization may, for example, be carried out at the start of the device and / or for several sensors of the plurality of sensors operating at the same capture frequency (and monitoring, for example, the same area).

[0129] The configuration of the sensor(s) may include sending (via the device's communication means) to the sensor concerned a command to adjust its measurement and / or synchronization frequency (optionally). Sending a command may be followed by receiving a message from the sensor confirming that this command has been taken into account and / or obtaining the current frequency of the sensor (at the device's request or at the sensor's initiative) to verify that the command has been taken into account).

[0130] As illustrated in FIG. 9, the method 900 may comprise obtaining 950 data from at least one of the sensors of the plurality of sensors. This data may comprise, for example, at least one indication of a distance between the sensor at the origin of this data and a physical element present in the measurement field of this sensor. This may be, for example, a physical element facing the sensor (such as the wall facing the sensor in the absence of occupation of the area monitored by the sensor).

[0131] According to the embodiments, the data can be sent by the sensors at the initiative of the sensors themselves (for example during each measurement) and / or at the request of the device 100. An input / output module of the device can for example be listening on at least one communication channel to receive data from one or more sensors. This can be, according to the embodiments, a channel dedicated to a sensor or a channel shared by several sensors. The designation of the communication channel (or communication channels) on which to listen can be carried out during the configuration 910 of the device.

[0132] Obtaining the distance data may be implemented multiple times (e.g., recurrently). Thus, in some embodiments, data from all of the plurality of sensors may be obtained (and processed according to the method of the present application) several tens to several hundred times per second.

[0133] It is noted that in certain embodiments, the measurement frequency of a sensor and the frequency of information feedback from this sensor to the device 100 may be different. Thus, depending on the embodiments, the sensors (or their support) may transmit to the device 100 all the measured distances, or only send back to the device 100 variations in distance (above a threshold value for example), or only the measured distances less than a first value (such as a first value

[0134] ("lower threshold") of the order of a few centimeters or a few tens of centimeters), or alternatively that the measured distances greater than a second value (upper threshold), or between a first and a second value. The first and / or second threshold value can be defined by configuration for example. Such embodiments make it possible to filter the distance data captured by each sensor before processing them

[0135] Alternatively, filtering before processing the distances received from the sensors can be performed by the device 100 (or a sensor support).

[0136] When the data from the sensors do not vary over time (or vary very little), this means that no activity (or movement) (or very little activity and / or movement) is detected by the sensors in their measurement field. On the contrary, in the case where distance data vary for at least one of the sensors, this means that the portion of the scene monitored in the measurement field of the sensor concerned and for which a distance measurement has varied is at least partially "occupied".

[0137] As illustrated in FIG. 9, the method 900 may comprise a calculation 960 of the value of an occupancy indicator of at least one zone of the monitored scene located in the capture field of the sensor taking into account the data obtained 950.

[0138] When the calculation reveals a change in the value of this indicator, compared to a previously calculated value (and stored by the device for example), the method may comprise on the one hand a storage (optional in certain embodiments) of the new value of the indicator, in association with an identifier of the zone concerned and / or of the sensor(s) of the zone concerned, and on the other hand an adjustment 970 of the frequency of at least one sensor. The adjustment may be carried out optionally. For example, it may or may not be carried out depending on the variation or the value of the occupancy index for at least one monitored zone. Thus, the frequency of at least one of the sensors of the zone concerned may be updated.More precisely, the adjustment may for example correspond to an increase, respectively a decrease, in the frequency of capture of a sensor when the occupancy indicator of the zone associated with this sensor is representative of an increase, respectively a decrease, in the occupancy of this zone (or vice versa).

[0139] In some embodiments, the capture frequency of at least one other sensor monitoring at least partially an area other than the area concerned can be updated. This other sensor can be chosen in some embodiments taking into account the occupancy index of this “other” area. It can be for example a sensor of an area whose occupancy index has a low current value. In some embodiments, this other sensor can be selected taking into account statistical data (such as a probability of occupancy of areas) or a history of occupancy of the areas. This statistical data or this history can be obtained by the device during its configuration 910 or dynamically during its operation.

[0140] As discussed above, frequency adjustment can allow the device to dynamically adapt the data capture made by the sensors to the events occurring in the monitored scene. Thus, sensors monitoring a commonly busy area may have, at a time t, a much faster capture frequency than those of some sensors monitoring commonly less busy areas.

[0141] Note that frequency adjustment can cause sensors on the same support (bar) to vary differently.

[0142] This situation is illustrated in Figure 10 where the monitored scene is a corridor. The sensors 150 of the zones 1010 very close to the walls or central zones will, for example, have lower capture frequencies than those of the sensors of the zones 1012 located in the usual circulation axes of people likely to cross paths.

[0143] The adjustment 970 of the capture frequency of a sensor can be implemented, in a similar manner to what was described for the parameterization 940 of the sensor(s) detailed above (and carried out for example “initially” when launching the method of the present application). Thus the adjustment can comprise sending a frequency modification command to a sensor, receiving confirmation that the command has been taken into account and / or obtaining the new current frequency of the sensor, after sending the command to verify that it has been taken into account.

[0144] As indicated above, depending on the embodiments, the adjustment may take into account the value of the occupancy index and / or its variation. For example, the frequency adjustment may be based on a correspondence table associating a particular capture frequency with a range of values ​​of the occupancy indicator. The adjusted frequency of the sensor(s) concerned is then that corresponding, in this correspondence table, to the calculated value of the indicator.

[0145] The adjustment may, according to another example, be proportional to the variation in the value of the indicator. In another embodiment, the adjustment may take into account the frequency of variation of the distances measured by at least one sensor. The greater this variation, the more frequented the area monitored by this sensor is.

[0146] In another embodiment, the adjustment may take into account a “group” score relating to one or more sensors (for example, to the sensors of the same support). A group score may, for example, be calculated from “unit” scores of the sensors concerned. For example, each sensor may be associated with a (unit) “score” of frequency relative and / or representative of the frequency of variation of the distances measured by this sensor. Such a group score may help to adjust (if necessary) the frequency of the sensors of the group concerned. For example, it may involve adjusting the frequency of several sensors to the same value or to different values ​​(according to a rule relating to the group, for example, a function of the relative positions of the sensors of the group).

[0147] The calculation 960 of the occupancy indicator and the adjustment 970 can be carried out multiple times, for example regularly, with a constant calculation (and adjustment) time “step”. It can also be a variable step (or time window) in certain embodiments (the size of the next time window varying for example according to the current variation of the occupancy indicator value).

[0148] In some embodiments, the capture (i.e. measurement) frequency of a sensor may be adjusted independently of those of the other sensors. However, the more the measurement frequency increases, the more the energy dissipated by the device increases. Also, in some embodiments, the adjustment of the measurement frequency of a first sensor may be compensated by an adjustment of the measurement frequency of at least one second sensor, other than this first sensor, so as to limit the overall energy consumed by the device.

[0149] For example, when the occupancy indicator of a first zone is representative of an increase, respectively a decrease, in the occupancy of the first zone compared to the previous calculation, the method may comprise both an increase, respectively a decrease, in the measurement frequency of the sensor concerned and a decrease, respectively an increase, in the measurement frequency of at least one other sensor of said plurality of sensors. According to the embodiments, this other sensor may be chosen (i.e. selected) by the device 100 randomly, and / or according to its configuration, and / or according to the positioning of the sensors coupled to the device, and / or according to the current values ​​of the occupancy indices of the different monitoring zones and / or past values ​​of these indices.

[0150] As illustrated in FIG. 9, the method 900 may comprise, in parallel or sequentially with the frequency adjustments 970 of the sensors, a processing 980 following the presence detection such as a generation of an alert following a detection of a movement or a presence, a counting of moving objects and / or a reconstruction of at least one 2D or 3D shape from the data obtained from the sensors at different measurement times.

[0151] For example, an alert may be generated in the event of a deviation from a detection history. For example, an alert may be generated upon detection of an unusual influx of traffic or, in embodiments where the method allows the detection of a direction of passage, of an unusual influx of passages in a direction other than the majority direction of passage according to the detection history (such as in the event of a fire for example). The 2D or 3D reconstruction may for example be carried out by one or more specific module(s) of the device 100, receiving the distance data obtained from the sensors (for example all the data obtained from the sensors over a time window or only the data obtained differing from the data obtained during a previous measurement) and positioning in a 2D (x, z) or 3D (x, y, z) reference frame the points corresponding to the different distance data received.

[0152] In such an embodiment, the method may comprise rendering the obtained 2D or 3D shape on a screen coupled to the device (for recognition or identification for example), storing the obtained 2D or 3D shape in a file local to the device and / or sending the 2D or 3D shape to another device via the communication means of the device 100.

[0153] The 2D or 3D reconstruction can take into account, in certain embodiments, only the last n measurement points received by a sensor (and obtained during the last measurement or the last k measurements made by this sensor) (with n and k natural integers not harmed), for example by progressively removing the points whose measurement was made outside the time window considered (for example the sliding time window corresponding to the last k measurements). The 3D reconstruction can also make it possible to obtain several temporally consecutive point clouds, thus creating a 3D shape. This 3D shape can be ephemeral for an observer. It will in fact appear then disappear progressively depending on the sliding time window considered.

[0154] This application may find applications in many fields, for example in the field of security, logistics, assistance in maintaining elderly people at home, and / or the supervision of industrial environments and / or sensitive environments. This may involve monitoring the movements of various objects (people, animals, vehicles, etc.). For example, the method of this application may be applied to monitoring the entries and / or exits of objects from a monitored scene.

[0155] In some embodiments, shape recognition performed on detected objects may help verify the presence or absence of certain features on an object (e.g., whether a person is wearing a helmet in a specific area).

[0156] At least some embodiments of the present application may make it possible to obtain a system and / or a device that is relatively economical in terms of energy cost and / or processing cost. Thus, lowering the capture frequencies of at least some sensors may help, on the one hand, to limit the energy consumption of the system and, on the other hand, to limit the processing carried out by the device 100 and the sensors. In particular, in certain embodiments, where in the absence of presence detection by a sensor, the corresponding capture frequency is reduced, the total energy consumption of the system will decrease in the absence of activity in the monitored scene. Such embodiments may help to lower (or at least limit) the overall consumption of the system, in particular during prolonged periods of absence of activity in the monitored scene.They can therefore help to achieve very low energy consumption, for systems intended to detect exceptional situations (theft or falling of objects for example) having a low probability of occurrence. This can make it possible, for example, to power the system with ambient energy (solar, heat, etc.), without the need for a wired energy source. Such power supply by ambient energy sources is, conversely, difficult to envisage, for example, with prior art systems with a constant capture frequency, or based on high-speed rotation (very energy-consuming) of a sensor or a reflector. The present application can thus help to offer new detection possibilities in situations where power supply via wired means is difficult, or even impossible (for example, in the open air, for rapid installation in a street (to count people in a demonstration, for example, etc.).

[0157] In at least some of its embodiments, for example when all of the sensors used are distance sensors, the method of the present application is also suitable for preserving the anonymity of individuals and more generally for complying with personal data protection rules (such as the General Data Protection Regulation (GDPR) in Europe).

[0158] Examples of implementation have been presented above where certain sensors could be of fixed position and / or orientation, the coverage of the scene by the sensors being achieved by the combination of the measurement fields (i.e. the detection fields) of the sensors. In a variant, at least one of the sensors can be mounted on a support whose position can vary dynamically. For example, in certain embodiments, one or more sensors can be mounted on a rotating support. The rotation can be controlled for example by the device 100. It can be an intermittent rotation (to change the position of the sensors following the occurrence of certain events (for tracking purposes for example) or a continuous rotation (the speed of which can be adjusted for example via the device 100) “scanning” the monitored scene.Such an embodiment may for example be adapted to the detection of a stationary object (such as a person facing equipment such as an ATM or a cash dispenser).

Claims

CLAIMS 1. Method implemented in an electronic device, comprising: Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor; An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

2. Method according to claim 1, wherein the method comprises an update of an occupancy indicator of said first zone as a function of said first data obtained and said updating of said measurement frequency of at least said first sensor is a function of a variation of said occupancy indicator of said first zone over a time window.

3. Method according to claim 1 or 2 wherein said first sensor is a distance sensor and wherein said first data comprises at least one indication of distance relative to said first sensor, of said at least one first physical element.

4. Method according to one of claims 1 to 3, wherein said updating of said measurement frequency of said at least one first sensor comprises an increase, respectively a decrease, of the measurement frequency of said first sensor during an increase, respectively a decrease, of the occupancy of said first zone.

5. Method according to one of claims 1 to 4, wherein the method comprises updating a measurement frequency of at least one second sensor of said plurality of sensors, other than said first sensor, as a function of a variation in an occupancy of said first zone over a time window.

6. Method according to claim 5, wherein said updating of said measurement frequency of said at least one second sensor comprises a decrease, respectively an increase, of the measurement frequency of said at least one second sensor of said plurality of sensors, during an increase, respectively a decrease, of the occupancy of said first zone.

7. Method according to claim 5 or 6, wherein said updating of said measurement frequency of said at least one first and / or second sensor takes into account the energy consumed by all of said plurality of sensors over said time window.

8. Method according to one of claims 5 to 7, wherein said second sensor is selected, from said plurality of sensors, according to occupancy indicators of the areas monitored by said plurality of sensors obtained from the measurements of said plurality of sensors.

9. Method according to one of claims 1 to 8, the longitudinal axes of said measurement fields of at least two sensors of said plurality of sensors are located in the same acquisition plane.

10. Method according to one of claims 1 to 9, where at least two sensors of said plurality of sensors are integrated into the same support coupled to said device.

11. The method of claim 10, wherein said support is breakable.

12. Method according to one of claims 1 to 11, where the method comprises a reconstruction of at least one 3D shape from the data obtained from the sensors and relating to the elements measured in said acquisition plane at different measurement times.

13. Electronic device comprising at least one processor configured to: Obtaining first data from at least one first sensor of a plurality of sensors, said first data comprising at least one indication relating to at least one first physical element present in at least one first zone of a scene monitored by said sensors, said first zone being at least partially located in the measurement field of said first sensor; An update of a measurement frequency of at least said first sensor, among said plurality of sensors, as a function of a variation in an occupancy of said first zone over a time window.

14. Electronic device according to claim 13 where the longitudinal axes of said measurement fields of at least two sensors of said plurality of sensors are located in the same acquisition plane.

15. Electronic device according to one of claims 13 or 14, wherein at least two sensors of said plurality of sensors are integrated into the same support coupled to said device.

16. Electronic device according to claim 15, wherein said support is breakable.

17. Electronic device according to claim 15 or 16, wherein said support is orientable.

18. Electronic device according to one of claims 15 to 17, wherein said support is mechanically and / or electronically assemblable with another support of at least one sensor of said plurality of sensors.

19. Electronic device according to one of claims 13 to 18, wherein the measurement fields of said plurality of sensors are disjoint.

20. Electronic device according to one of claims 13 to 19, wherein at least two sensors of said plurality of sensors have identical measurement directions.

21. Electronic device according to one of claims 13 to 20, wherein at least two sensors of said plurality of sensors have different measurement directions.

22. Electronic device according to one of claims 13 to 21, where the measurement directions of at least two sensors of said plurality of sensors are located in the same acquisition plane.

23. Electronic device according to claim 22, wherein said at least two sensors are aligned and said acquisition plane is defined by an alignment of said at least two sensors and by said measurement directions.

24. Electronic device according to one of claims 13 to 23, wherein said acquisition plane is a plane perpendicular to a main direction of movement of an object of said scene to be monitored.

25. Computer program product comprising instructions for implementing, when said computer program is executed by a processor of an electronic device, a method according to one of claims 1 to 12.

26. Recording medium readable by a processor of an electronic device and on which is recorded a computer program comprising instructions for implementing, when the computer program is executed by the processor, a method according to one of claims 1 to 12.

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